Formulation of Dipyridamole Sustained Release Tablet Using Floating System

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Lenny Mauilida Valentina

2011-06-01

Full Text Available Dipyridamole is a drug for prevention of postoperative thromboembolic complication of heart valve replacement and long term therapy of angina pectoris will be well absorbed in stomach. To maintain therapeutic plasma concentration in long time and to increase bioavalaibility is needed a sustained release dosage form having the long residence time in the stomach. The objective of this research was to make floating sustained release tablet of dipyridamole conforming to the requirement that was set up by dipyridamol therapeutic concentration. Tablets were made by wet granulation method using aquadest as a liquid binder, HPMC K4M, Ac-di-sol, Avicel PH 102, talk, and Mg stearat. Dissolution assay was carried out using type 2 release tester at rotation speed of 50 rpm in medium 900 mL HCl 0.1 N at 37 ± 0.5 °C for 8 hours. The formulation containing of 50 mg dipirydamole, HPMC K4M (30%, Ac-di-sol (20%, Avicel PH 102 (37%, talk (2%, and Mg stearat (1% released 59.61 ± 6.73% and 89.34 ± 5.87% of dipyridamole respectively after 4 and 8 hours that conformed to the requirement.

Risk-benefit of dipyridamole loading thallium-201 myocardial scintigraphy

International Nuclear Information System (INIS)

Ueshima, Kenji; Ogiu, Naonori; Musha, Takehiko; Moriai, Naoki; Miyakawa, Tomohisa; Nakai, Kenji; Hiramori, Katsuhiko

1995-01-01

This study assessed the accuracy of dipyridamole-stressed thallium-201 scintigraphy in the detection of myocardial ischemia, as well as the associated complications and their background factors. Fifty consecutive patients (33 men and 17 women; a mean age of 67 years) unable to undergo exercise thallium imaging were examined. R waves on resting ECG, the occurrence of ischemic changes on exercise ECG, asynergy on left ventriculography and dobutamine-stressed two-dimensional echocardiography, uptake of FEG on PET, and coronary angiographic findings were comprehensively assessed to determine the accuracy of the present scintigraphy. The sensitivity, specificity, accuracy, positive predictive value, and negative predictive value were 60.4%, 94.2%, 89.7%, 83.0%, and 82.9%, respectively. These findings yielded satisfactory detectability of dipyridamole-stressed thallium-201 scintigraphy for myocardial ischemia. The present scintigraphy had a high sensitivity and specificity for the left anterior descending artery; however, it had a high specificity but low sensitivity for the other arteries. A majority of complications during the scintigraphy was transient, mild decrease in blood pressure, which was found especially when ischemia was present in the left circumflex artery and chest pain occurred during dipyridamole stress. Dipyridamole stress is considered to be contraindicated for patients with unstable angina. (N.K.)

Ecg changes after dipyridamole infusion in patients undergoing myocardial perfusion imaging

International Nuclear Information System (INIS)

Taherpour, M.; Zakavi, R.; Ariana, K.

2002-01-01

Dipyridamole is used as the main pharmacological stress agent in patient referred for myocardial perfusion imaging. This vasodilator agent makes difference between normal and abnormal coronary perfusion. Some authors believe that post-Dipyridamole Ecg changes have low sensitivity and relatively high specificity for ischemic detection. This study tries to evaluate this issue. All patients who referred to nuclear medicine department for Myocardial Perfusion Imaging and were not suitable for treadmill E T T, and had no L BBB pattern in basal Ecg were included in the study. Basal and post Dipyridamole Ecg were interpreted with a cardiologist after infusion of 142 u g/kg/min of Dipyridamole and all changes as well as basal Ecg abnormalities were recorded. Also Q Tc were calculated in all Ecg records: M P Is were interpreted by a nuclear medicine specialist and summed stress and rest scores were determined. Two hundred patients including 89 female (44.5%) and 111 male (55.5%) with a mean age of 55.2 years and age range of 30-85 years were studied. Mean basal and post Dipyridamole heart rates were 72.2/min and 84.8/min and mean basal and post Dipyridamole Qt Cs were 419.6 msec and 435.7 msec respectively. New Ecg changes were noted in 22.5% of cases and consisted of 1% T-wave flattening, 1% T-wave inversion, 16.5% St depression and 4% Pseudo normalization. Horizontal pattern was the main type of St segment depression (83.%) among new S T changes. Mean St depression severity was 0.8 mm with a range of 0.5-2 mm. New St depression was noted in lateral leads (Excluding high lateral) in 62.5% of new S T changes. M P I was interpreted normal in 4% of cases and showed some degrees of ischemia in 42% of the cases. The mean post Dipyridamole heart rate increment, was 11.2/ min patients with abnormal scintigraphy (infarct and/or ischemia) compared to 14.5/ min in normal cases. (P=0.009). Also Qt c increment in patients with ischemia was significantly more than patients with simple

Dipyridamole may induce migraine in patients with migraine without aura

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Kruuse, C; Lassen, L H; Iversen, Helle Klingenberg

2006-01-01

Dipyridamole inhibits phosphodiesterase 5 (PDE5) and adenosine re-uptake. The most prominent side-effect is headache. We examined the migraine-generating effects of dipyridamole as well as the cerebral blood velocity response in a single-blind study, including 10 patients with migraine without aura...... repeatedly. Headache was induced in all migraine patients and in eight of 10 healthy subjects (P = 0.47) with no significant difference in headache intensity (P = 0.53). However, five patients but only one healthy subject experienced the symptoms of migraine without aura, according to ICHD-2 criteria, within....... Thus, dipyridamole induces symptoms of migraine and an initial decrease in V(mca) in migraine patients, but not significantly more than in healthy subjects. This relatively low frequency of migraine induction, compared with nitric oxide donors and sildenafil, is probably due to the less specific action...

Self-microemulsifying drug delivery system for improved oral bioavailability of dipyridamole: preparation and evaluation.

Science.gov (United States)

Guo, Feng; Zhong, Haijun; He, Jing; Xie, Baogang; Liu, Fen; Xu, Helin; Liu, Minmin; Xu, Chunlian

2011-07-01

Dipyridamole shows poor and variable bioavailability after oral administration due to pHdependent solubility, low biomembrane permeability as well as being a substrate of P-glycoprotein. In order to improve the oral absorption of dipyridamole, a self-microemulsifying drug delivery system (SMEDDS) for dipyridamole was prepared and evaluated in vitro and in vivo. The optimum formulation was 18% oleic acid, 12% Labrafac lipophile WL 1349, 42% Solutol HS 15 and 28% isopropyl alcohol. It was found that the performance of self-microemulsification with the combination of oleic acid and Labrafac lipophile WL 1349 increased compared with just one oil. The results obtained from an in vitro dissolution assay indicated that dipyridamole in SMEDDS dissolved rapidly and completely in pH 6.8 aqueous media, while the commercial drug tablet was less soluble. An oral bioavailability study in rats showed that dipyridamole in the SMEDDS formulation had a 2.06-fold increased absorption compared with the simple drug suspension. It was evident that SMEDDS may be an effective approach to improve the oral absorption for drugs having pH-dependent solubility.

Persistent chest pain following oral dipyridamole for thallium 201 myocardial imaging

International Nuclear Information System (INIS)

Kwai, A.H.; Jacobson, A.F.; McIntyre, K.M.; Williams, W.H.; Tow, D.E.

1990-01-01

A patient was admitted to the hospital with acute chest pain. After acute myocardial infarction was ruled out, he underwent a stress thallium 201 scintigraphy using oral dipyridamole and developed persistent angina with sedimentation time segement elevation. This complication has not been reported previously. It is recommended that appropriate intervention be available if severe ischemia develops following administration of dipyridamole for diagnostic imaging. (orig.)

The clinical value of chest pain during thallium-201 scintigraphy with dipyridamole

International Nuclear Information System (INIS)

Takeishi, Yasuchika; Tono-oka, Ichiro; Meguro, Mitsuhiko; Hoshi, Hikaru; Yamaguchi, Yoshiko; Masakane, Ikuto; Tsuiki, Kai; Yasui, Shoji

1990-01-01

Sixty patients with suspected coronary artery disease underwent both dipyridamole-loaded thallium-201 scintigraphy and cardiac catheterization. Thirty four patients (57%) developed chest pain during dipyridamole stress testing (the pain group), and the other 26 did not (the no-pain group). Regarding sex, age, history of myocardial infarction, and the presence of coronary artery disease, there was no difference between the pain and no-pain groups. The pain group had significantly increased pulse rate and rate-pressure-product, as compared with the no-pain group. ST depression was more frequently observed in the pain group than the no-pain group. There was no significant difference in the angiographic involvement and the severity of coronary artery disease between the two groups. Nor was there significant difference in dipyridamole-loaded scintigraphic findings, such as defect size, and the extent and degree of decreased washout. However, for patients without a history of myocardial infarction, the pain group had a farther decreased washout than the no-pain group. Chest pain associated with iv injection of dipyridamole may have implications for the occurrence of serious ischemia. (N.K.)

Value of dipyridamole stress 201Tl myocardial SPECT in detecting dysfunction of coronary microcirculation

International Nuclear Information System (INIS)

Lou Ying; Jiang Jinqi; Xie Wenhui; Yuan Fang; Wang Tong; Yang Yiqing

2012-01-01

Objective: To evaluate the value of dipyridamole stress 201 Tl myocardial SPECT in detecting dysfunction of coronary microcirculation. Methods: Forty-eight patients diagnosed with cardiac syndrome X underwent dipyridamole stress 201 Tl myocardial SPECT. Dipyridamole (0.56 mg/kg) was intravenously injected over 4 min followed by 201 Tl (111 MBq) injection at 2 min after dipyridamole administration. Image was acquired at 10 min and 240 min post-injection and co-analyzed by over two experienced doctors in nuclear medicine after three-dimensional reconstruction. The patients with 'reverse redistribution' underwent repeated dipyridamole stress 201 Tl SPECT after medical therapy for 2 weeks. The clinical symptoms and results of the treadmill exercise test pre-and post-therapy were compared. Results: Forty two patients (42/48, 87.50%) showed segmental defects: 'reverse redistribution' on delayed (240 min) 201 Tl images. After medical treatment, 36 cases of the 42 'reverse redistribution' patients had improvement in both clinical symptoms and treadmill exercise test. Post-treatment 201 Tl imaging showed improvement in 45/49 (91.84%) defect segments. Six of the 42 patients had no improvement in clinical symptoms and/or treadmill exercise test. Post-treatment 201 Tl imaging showed no improvement in all the 7 defect segments on the first scan. Conclusion: Dipyridamole stress 201 Tl myocardial SPECT may be valuable in evaluation of impaired coronary microcirculation associated with cardiac syndrome X. (authors)

The incidence of serious hemodynamic changes in physically-limited patients following oral dipyridamole challenge before thallium-201 scintigraphy

International Nuclear Information System (INIS)

Kahn, D.; Argenyi, E.A.; Berbaum, K.; Rezai, K.

1990-01-01

Dipyridamole has liberalized referrals for stress TI-201 chloride (thallium) studies at the Iowa City Veterans Administration Medical Center. Seventy-five percent of referrals now receive dipyridamole and, unlike patients who tolerate conventional exercise testing, these patients are often quite debilitated. Therefore, the hemodynamic consequences of dipyridamole were reviewed in 120 consecutive, physically-limited patients referred for thallium scintigraphy following an average oral dose of 5.4 mg/kg. Each patient's blood pressure was measured every 5 minutes for 1 hour after dipyridamole and compared with several clinical factors to determine if blood pressure change was predictable. In all patients, blood pressure changed from 136 +/- 21/83 +/- 15 (mean +/- 1 SD) to 117 +/- 25/72 +/- 15 following dipyridamole administration. One hundred nine of the 120 patients had a blood pressure decline from 137 +/- 21/82 +/- 12 to 113 +/- 21/70 +/- 13. Of the 109, 43% (N = 47) had a systolic blood pressure decline greater than 20 mmHg, 16% (n = 18) greater than 40 mmHg, and 13% (n = 14) greater than 50 mmHg. Thirteen percent (n = 14) required emergent reversal of the dipyridamole with aminophylline. Significant hypotension is relatively common but generally unpredictable after oral dipyridamole. Therefore, patient eligibility criteria should be carefully considered; strict hemodynamic monitoring must be routine in the usual patient undergoing thallium scintigraphy after oral dipyridamole challenge

Intrinsic washout rates of thallium-201 in normal and ischemic myocardium after dipyridamole-induced vasodilation

International Nuclear Information System (INIS)

Beller, G.A.; Holzgrefe, H.H.; Watson, D.D.

1985-01-01

Infusion of dipyridamole has been suggested as an alternative to exercise stress for myocardial perfusion imaging for detection of ischemia, but the mechanism and significance of thallium-201 ( 201 Tl) redistribution after administration of dipyridamole are uncertain. If disparate intrinsic cellular efflux rates of 201 Tl from normal and relatively underperfused myocardium in response to dipyridamole-induced vasodilation were observed, this could explain delayed 201 Tl redistribution. We investigated the effect of an intravenous infusion of 0.15 mg/kg dipyridamole on the intrinsic myocardial washout rate of 201 Tl as measured with a gamma-detector probe after intracoronary injection (50 muCi) of the radionuclide in open-chested anesthetized dogs. In six normal dogs the t 1/2 for intrinsic 201 Tl washout from the myocardium was 89 +/- 11 min (SE) at control conditions and became more rapid at 59 +/- 10 min (p . .0001) after dipyridamole. This corresponded to a significant increase in microsphere-determined epicardial (0.95 +/- 0.11 to 2.23 +/- 0.46 ml/min/g; p . .01) and endocardial (0.86 +/- 0.10 to 1.53 +/- 0.27; p . .029) flows. In 12 dogs with a critical coronary stenosis, the 201 Tl intrinsic washout rate slowed from 70 +/- 5 to 104 +/- 6 min (p . .0001) after production of the stenosis and slowed even further to 169 +/- 21 min (p . .003) after dipyridamole

Intravenous dipyridamole thallium-201 SPECT imaging in patients with left bundle branch block

International Nuclear Information System (INIS)

Rockett, J.F.; Wood, W.C.; Moinuddin, M.; Loveless, V.; Parrish, B.

1990-01-01

Tl-201 exercise imaging in patients with left bundle branch block (LBBB) has proven to be indeterminate for significant left anterior descending (LAD) coronary artery stenosis because of the presence of immediate septal perfusion defects with redistribution on delayed images in almost all cases. Tl-201 redistribution occurs regardless of the presence or absence of LAD stenosis. Nineteen patients having LBBB were evaluated with dipyridamole Tl-201 SPECT. Fourteen of these subjects had normal dipyridamole Tl-201 SPECT imaging. Three patients had normal coronary angiograms. None of the remaining 11 patients with normal dipyridamole Tl-201 SPECT images was found to have clinical coronary artery disease in a 5-11 month follow-up period. Five patients had abnormal septal perfusion. Four underwent coronary angiography. One had a significant LAD stenosis. The single patient with septal redistribution who refused to undergo coronary angiography died shortly thereafter of clinical coronary artery disease. This preliminary work suggests that dipyridamole Tl-201 SPECT may be more useful for excluding LAD stenosis in patients with LBBB than Tl-201 exercise imaging

Platelet adhesion studies on dipyridamole coated polyurethane surfaces

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Aldenhoff Y. B.J.

2003-06-01

Full Text Available Surface modification of polyurethanes (PUs by covalent attachment of dipyridamole (Persantinregistered is known to reduce adherence of blood platelets upon exposure to human platelet rich plasma (PRP. This effect was investigated in further detail. First platelet adhesion under static conditions was studied with four different biomaterial surfaces: untreated PU, PU immobilised with conjugate molecule 1, PU immobilised with conjugate molecule 2, and PU immobilised with conjugate molecule 3. In PU immobilised with 1 dipyridamole is directly linked to the surface, in PU immobilised with 2 there is a short hydrophilic spacer chain in between the surface and the dipyridamole, while conjugate molecule 3 is merely the spacer chain. Scanning electron microscopy (SEM was used to characterise platelet adhesion from human PRP under static conditions, and fluorescence imaging microscopy was used to study platelet adhesion from whole blood under flow. SEM experiments encompassed both density measurements and analysis of the morphology of adherent platelets. In the static experiments the surface immobilised with 2 showed the lowest platelet adherence. No difference between the three modified surfaces emerged from the flow experiments. The surfaces were also incubated with washed blood platelets and labeled with Oregon-Green Annexin V. No capture of Oregon-Green Annexin V was seen, implying that the adhered platelets did not expose any phosphatidyl serine at their exteriour surface.

Brain SPECT using dipyridamole for evaluation of vascular reserve

International Nuclear Information System (INIS)

Kim, Su Zy; Park, Chan Hee; Yoon, Soo Hwan; Pai, Moon Sun; Yoon, Suk Nam; Cho, Kyung Kee

1997-01-01

Baseline and stress brain SPECT studies using CO 2 inhalation, acetazolamide (Diamox R ) and adenosine administrations have been used in the evaluation of cerebral vascular reserve. Recently dipyridamole (Persantine R ) which is one of the pharmacologic myocardial perfusion SPECT agents as a potent vasodilator is suggested as another cerebral vasodilator. IV Diamox R is not available in Korea. Therefore, the purpose of our study was to evaluate dipyridamole in stress brain SPECT in patients with Moya Moya disease. Eight patients with angiographically proven Moya Moya disease were studied. Their ages ranged from 7 to 62 year old. There were 4 males and 4 females. Each patient had a baseline and persantine brain SPECT studies with 1 to 3 days' interval. Dipyridamole was given intravenously at a dose of 0.56 mg/kg over 4 minutes while watching vital signs such as blood pressure, heart rate, and electrocardiogram. Three minutes after the completion of the infusion, 99mTc-ECD (0.2 mCi/Ib body weight) was injected. Brain SPECT was performed 30 minutes later using a tripple head gamma camera equipped with LEHR collimators. A total of 128 projections with an acquisition time of 30 second per projection was obtained and reconstructed by filtered back projections without attenuation correction. The difference between the baseline and persantine studies was analysed by visual and semiquantitavely. During the infusion of persantine, heart rate, blood pressure and side effects such as headache, chest discomfort were similar to the persantine myocardial SPECT studies. Five of eight patients showed a significant decrease in rCBF on persantine brain SPECT in comparison to the baseline study. The remaining three revealed no significant change in rCBF. Our study suggests that the dipyridamole stress brain SPECT is feasible and useful in assessing cerebral blood flow reserve. However we need to evaluate more number of patients in the future

Thallium-201 myocardial imaging during pharmacologic coronary vasodilation: comparison of oral and intravenous administration of dipyridamole

International Nuclear Information System (INIS)

Taillefer, R.; Lette, J.; Phaneuf, D.C.; Leveille, J.; Lemire, F.; Essiambre, R.

1986-01-01

Although the diagnostic utility of thallium-201 myocardial imaging after dipyridamole infusion is well established, the intravenous form of the drug is not yet commercially available in North America. Fifty patients referred for coronary angiography were prospectively studied. Within a 2 week period, each patient underwent cardiac catheterization and thallium-201 myocardial imaging after both oral and intravenous dipyridamole administration. For the oral protocol, patients were randomly assigned to treatment with either 200 or 400 mg of dipyridamole in tablet form. Coronary artery stenoses of 70% or greater were considered significant. For the 25 patients who received a 200 mg oral dose of dipyridamole, the scintigraphic study showed perfusion defects in 65% of patients with significant coronary artery disease after the oral dose and in 85% of patients after the intravenous dose. For the 25 patients who received a 400 mg oral dose, the sensitivity of the scintigram was 84% after the oral dose and 79% after the intravenous dose. Except for headache and nausea, side effects were less severe and less frequent with oral (either 200 or 400 mg) than with intravenous dipyridamole. Because of the delayed and variable absorption of dipyridamole tablets, the oral studies required a longer period of medical supervision (45 to 60 minutes), and aminophylline was empirically administered after completion of the first set of thallium-201 images. It is concluded from this study that thallium-201 myocardial imaging after coronary vasodilation with a 400 mg oral dose of dipyridamole is a safe, widely available and reliable alternative for the evaluation of coronary artery disease in patients unable to achieve an adequate exercise level on stress testing

Two-dimensional Doppler echocardiographic correlation of dipyridamole-thallium stress testing with isometric handgrip

International Nuclear Information System (INIS)

Whitfield, S.; Aurigemma, G.; Pape, L.; Leppo, J.

1991-01-01

To determine how frequently new wall-motion abnormalities that are indicative of ischemia accompany thallium redistribution, 47 consecutive patients underwent two-dimensional, echocardiography during routine dipyridamole-thallium stress testing. A secondary aim of the study was to determine whether the addition of isometric handgrip exercises to the standard dipyridamole imaging protocol increased the frequency of wall-motion abnormalities or thallium redistribution. Echocardiograms and thallium scans were independently interpreted, and wall-motion abnormalities that appeared with dipyridamole, handgrip exercise, or both were compared with results of thallium imaging. Five of 24 patients with thallium redistribution had new wall-motion abnormalities, and the extent (number of segments) of thallium redistribution in these five patients was significantly greater than in those who did not have well-motion abnormalities (p less than 0.03). The addition of isometric handgrip exercises to the imaging protocol did not distinguish between patients with and without new wall-motion abnormalities or thallium redistribution. Thus new wall-motion abnormalities infrequently accompany thallium redistribution in routine dipyridamole stress testing in spite of the addition of handgrip exercises, but when new wall-motion abnormalities are present, they are associated with a greater area of thallium redistribution

Myocordial perfusion SPECT with dipyridamole stress test in cardiac syndrome X

International Nuclear Information System (INIS)

Czepczynski, R.; Smolarek, I.; Sowinski, J.; Rogacka, D.; Kazmierczak, M.; Wysocki, H.

2006-01-01

Cardiac syndrome X defines patients with typical anginal chest pain, a positive exercise ECG stress test and angiographically normal coronary arteries. Aim of this study was to evaluate the role of myocardial perfusion SPECT with dipyridamole stress in the diagnosis of cardiac syndrome X. Patients, methods: 68 patients with syndrome X aged 32 to 60 years were subjected to myocardial imaging using 99m Tc-MIBI according to the two-days protocol: at rest and after dipyridamole infusion. Semiquantitative evaluation of the images was based on the assessment of 99m Tc-MIBI uptake in 17 myocardial segments using a 5-points scale (0 point - normal uptake, 4 points - no uptake). Scores obtained in each segment were summed up, constituting the summed rest score (SRS) and summed stress score (SSS). Results: mean SRS was 7.9 ± 4.8 and mean SSS was 7.2 ± 4.4 (non-significant difference). Individual comparison of SRS and SSS values revealed three patterns of scintigraphic images: (1) in 25 patients (36.8%), a paradoxical improvement of perfusion at stress images was found, (2) in 23 patients (33.8%), the myocardial perfusion deteriorated after dipyridamole, (3) in 20 patients (29.4%), no significant change of the myocordial perfusion between rest and stress images occurred. Conclusions: in cardiac syndrome X, myocardial SPECT with dipyridamole stress shows different patterns of myocardial perfusion that reflects heterogeneity of this pathology. (orig.)

Dipyridamole reduces penile apoptosis in a rat model of post-prostatectomy erectile dysfunction

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Omer Kutlu

Full Text Available ABSTRACT Purpose: Despite the nerve-sparing technique, many patients suffer from erectile dysfunction after radical prostatectomy (RP due to cavernous nerve injury. The aim of this study was to evaluate dipyridamole as a potential treatment agent of post-radical prostatectomy erectile dysfunction. Material and methods: A total of 18 male Sprague-Dawley rats were randomized into three experimental Groups (SHAM+DMSO, BCNI+DMSO and BCNI+DIP. An animal model of bilateral cavernous nerve crush injury (BCNI was established to mimic the partial nerve damage during nerve-sparing RP. After creating of BCNI, dimethyl sulphoxide (DMSO was administered transperitoneally as a vehicle to SHAM+DMSO and BCNI+DMSO Groups. BCNI+DIP Group received dipyiridamole (10mg/kg/day as a solution in DMSO for 15 days. Afterwards, rats were evaluated for in vivo erectile response to cavernous nerve stimulation. Penile tissues were also analyzed biochemically for transforming growth factor-β1 (TGF-β1 level. Penile corporal apoptosis was determined by TUNEL method. Results: Erectile response was decreased in rats with BCNI and there was no significant improvement with dipyridamole treatment. TGF-β1 levels were increased in rats with BCNI and decreased with dipyridamole treatment. Dipyridamole led to reduced penile apoptosis in rats with BCNI and there was no significant difference when compared to sham operated rats. Conclusions: Although fifteen-day dipyridamole treatment has failed to improve erectile function in rats with BCNI, the decline in both TGF-β1 levels and apoptotic indices with treatment may be helpful in protecting penile morphology after cavernous nerve injury.

Myocardial uptake and clearance of thallium-201 in normal subjects: comparison of dipyridamole-induced hyperemia with exercise stress

International Nuclear Information System (INIS)

Ruddy, T.D.; Gill, J.B.; Finkelstein, D.M.; Strauss, H.W.; McKusick, K.A.; Okada, R.D.; Boucher, C.A.

1987-01-01

Thallium-201 uptake and clearance after dipyridamole infusion may differ from that after exercise stress because the hemodynamic effects of these two interventions are different. In this study of normal volunteers, thallium kinetics after dipyridamole (n = 13) were determined from three serial image sets (early, intermediate and delayed) and from serial blood samples and compared with thallium kinetics after exercise (n = 15). Absolute myocardial thallium uptake was greater after dipyridamole compared with exercise (p less than 0.0001), although the relative myocardial distribution was similar. The myocardial clearance (%/h) of thallium was slower after dipyridamole than it was after exercise. Comparing dipyridamole and exercise, the differences in clearance were large from the early to the intermediate image (anterior, -11 +/- 17 versus 24 +/- 5, p = 0.0005; 50 degrees left anterior oblique, -7 +/- 11 versus 15 +/- 8, p = 0.004; 70 degrees left anterior oblique, 3 +/- 9 versus 21 +/- 6, p = 0.001). In contrast, the differences in clearance were small from the intermediate to the delayed image (anterior, 15 +/- 4 versus 20 +/- 2, p = 0.025; 50 degrees left anterior oblique, 15 +/- 4 versus 19 +/- 3, p = 0.13; 70 degrees left anterior oblique, 15 +/- 3 versus 18 +/- 2, p = 0.047). Thallium uptake and clearance in the liver, splanchnic region and spleen were greater after dipyridamole (p less than 0.001). Blood thallium levels were greater after dipyridamole (p less than 0.05) and cleared more slowly (p = 0.07). Thus, myocardial thallium-201 uptake and clearance after dipyridamole infusion differ from thallium kinetics after exercise. This difference is, in part, related to associated differences in extracardiac and blood kinetics. Diagnostic criteria for the detection of abnormal thallium-201 clearance must be specific for the type of intervention

Technetium-99m sestamibi myocardial tomography based on dipyridamole echocardiography testing in hypertensive patients with chest pain

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Schillaci, O. [Section of Nuclear Medicine, Department of Experimental Medicine and Pathology, University ``La Sapienza``, Rome (Italy); Moroni, C. [Department of Internal Medicine, University ``La Sapienza``, Rome (Italy); Scopinaro, F. [Section of Nuclear Medicine, Department of Experimental Medicine and Pathology, University ``La Sapienza``, Rome (Italy); Tavolaro, R. [Section of Nuclear Medicine, Department of Experimental Medicine and Pathology, University ``La Sapienza``, Rome (Italy); Danieli, R. [Section of Nuclear Medicine, Department of Experimental Medicine and Pathology, University ``La Sapienza``, Rome (Italy); Bossini, A. [Department of Internal Medicine, University ``La Sapienza``, Rome (Italy); Cassone, R. [Department of Internal Medicine, University ``La Sapienza``, Rome (Italy); Colella, A.C. [Section of Nuclear Medicine, Department of Experimental Medicine and Pathology, University ``La Sapienza``, Rome (Italy)

1997-07-01

The aim of this study was to evaluate the diagnostic capability of technetium-99m sestamibi tomography based on dipyridamole echocardiography testing in hypertensives with chest pain, and to compare the scintigraphic results with those of coronary angiography, exercise electrocardiography and dipyridamole echocardiography. Forty subjects with mild to moderate hypertension, chest pain and no previous myocardial infarction were submitted to {sup 99m}Tc-sestamibi tomography (at rest and after high-dose dipyridamole echocardiography) and to exercise electrocardiography testing. At coronary angiography 22 patients (group A) had significant epicardial coronary artery disease ({>=}70% stenosis of at least one major vessel) and 18 normal main coronary vessels (group B). Dipyridamole {sup 99m}Tc-sestamibi imaging was positive in 21/22 patients of group A and in 5/18 of group B. Dipyridamole echocardiography was positive in 18/22 patients of group A and in 5/18 of group B. Exercise electrocardiography was positive in 15/22 patients of group A and in 11/18 of group B. Four out of five subjects in group B with positive results in all the tests showed a slow run-off of angiographic contrast medium, probably due to small-vessel disease. Significant epicardial coronary artery disease in hypertensives with chest pain is unlikely when dipyridamole {sup 99m}Tc-sestamibi tomography is negative. When scintigraphy is positive, either epicardial coronary artery disease or a small-vessel disease condition is possible. The association of scintigraphy with dipyridamole echocardiography testing allows the assessment of contractile function and myocardial perfusion by a single pharmacological stress. (orig./AJ). With 3 figs., 2 tabs.

Coronary spasm induced by dipyridamole

International Nuclear Information System (INIS)

Wartski, M.; Caussin, C.; Lancelin, B.

2001-01-01

A 59 years old man was admitted at hospital for recurrent instable angina 1 month after coronary artery bypass surgery. Coronary artery disease started with a transmural antero-septo-apical myocardial infarction without thrombolysis and a percutaneous angioplasty with endo-prothesis on proximal left anterior descendant artery (LAD) is performed Because of recurrent rest angina and subacute stent thrombosis, a coronary artery bypass surgery (CABG) is performed with anastomosis of the left internal thoracic artery on LAD. The patient is admitted for recurrent rest angina one month after CABG. On ECG performed during chest pain, a ST-T segment elevation occurred on inferior leads. Coronary angiography showed no significant stenosis on endo-prothesis and no bypass graft dysfunction. Dipyridamole scintigraphy was realized. 2 minutes after the beginning of Dipyridamole infusion, a ST-T elevation occurred on inferior leads and two marked antero-septal and inferior defects were noticed on myocardial scintigraphy. Images at rest showed a clear improvement in the anterior wall and the inferior wall became normally perfused Patient was treated with anti-spastic drugs and a new coronarography with methyl-ergotamine test was performed inducing chest pain, ST-T elevation on inferior leads and tri-truncular coronary spasm. Patient's treatment was then modified with introduction of Nifedipine. The patient did not experienced new recurrent chest pain and remained totally asymptomatic few months later. (authors)

Usefulness of dipyridamole stress myocardial imaging in patients who have exercise limitations due to various orthopedic disorders

International Nuclear Information System (INIS)

Tagawa, Hirofumi; Ashihara, Toshiaki; Fukuyama, Takaya; Matsui, Kanji; Yamamoto, Sumiki; Yamamoto, Susumu

1994-01-01

To evaluate the presence of coronary artery disease in patients unable to exercise adequately because of chronic rheumatoid arthritis, osteoarthritis, hip bone fractures or disk herniation, we performed dipyridamole-stress thallium-201 myocardial imaging in thirty-three patients. Twelve of the 33 patients showed perfusion defect and redistribution by thallium imaging. Coronary angiography was performed in 9 patients out of these 12 dipyridamole-positive patients and significant coronary artery stenosis was detected in 7 of them (78%). Due to these results of dipyridamole-imaging and coronary angiograms, surgical intervention for the underlying bone or joint disorder was performed under cardioprotective strategy in 15 patients, in which no cardiovascular events occurred. Thus, dipyridamole-stress myocardial imaging is a satisfactory alternative to the exercise test for detecting coronary artery disease in patients with bone or joint disorders. (author)

High Performance Liquid Chromatographic Method for Determination of Dipyridamole in Human Plasma

Directory of Open Access Journals (Sweden)

DAVOOD BEIGI BAND ARAB ADI

1999-08-01

Full Text Available A simple, rapid and specific high-performance liquid chromatographic procedure is reported for"nquantitative determination of dipyridamole in human -plasma. The assay uses a reversed-phase"nhigh-performance liquid chromatographic (HPLC and UV detection at 280nm and has a limit"nof detection of approximately 5ng/mL. The mobile phase consists of MeOH-H20 (60:40"nadjusted to pH 3.3. Dipyridamole was extracted from plasma by back-extraction procedure, with"npropranolol as the internal standard. The reproducibility of the method is satisfactory

Is the antiproteinuric effect of dipyridamole hemodynamically mediated

NARCIS (Netherlands)

de Jong, P. E.; van der Meer, J.; van der Hem, G. K.; de Zeeuw, D.

1988-01-01

We studied the acute antiproteinuric and renal hemodynamic effect of dipyridamole 30–60 mg intravenously in 13 salt-depleted patients with the nephrotic syndrome of different etiology. Whereas mean arterial pressure did not change, a small fall in glomerular filtration rate with a concomitant fall

Myocardial 201Tl washout after combined dipyridamole submaximal exercise stress: Reference values from different patient groups

International Nuclear Information System (INIS)

Fridrich, L.

1989-01-01

Dipyridamole stress is favorable in patients unable to exercise maximally for 201 Tl myocardial scintigraphy. Aside from an analysis of uptake defects, proper washout analysis can be limited by heart rate variations when isolated dipyridamole stress is used. Heart rate standardized 201 Tl washout kinetics after a combined dipyridamole and submaximal exercise stress protocol (CDSE), feasible in elderly patients as well as in patients with peripheral artery disease, were therefore studied to investigate the 201 Tl washout after CDSE in differently defined patient groups: Group I comprised 19 patients with documented heart disease and angiographically excluded coronary artery disease (CAD); group II contained 17 patients with a very low likelihood of CAD determined by both normal exercise radionuclide ventriculography and normal 201 Tl uptake. Group III comprised 56 patients with a 50% pretest likelihood of CAD but normal 201 Tl uptake. Mean washout values were nearly identical in all groups. Despite similar uptake patterns, however, washout standardized by CDSE was significantly lower than the normal washout values after maximal treadmill exercise. Thus an obviously lower 201 Tl washout after CDSE than after maximal treadmill exercise must be considered if washout analysis criteria after dipyridamole are applied to evaluate ischemic heart disease. Nevertheless, heart rate elevation achieved by additional submaximal exercise stress seems necessary, adequate and clinically safe for standardisation of washout analysis in dipyridamole 201 Tl scintigraphy. (orig.)

Effects of dipyridamole-induced vasodilation on myocardial uptake and clearance kinetics of thallium-201

International Nuclear Information System (INIS)

Beller, G.A.; Holzgrefe, H.H.; Watson, D.D.

1983-01-01

Myocardial thallium-201 (201Tl) uptake and clearance after intravenous administration of dipyridamole (150 micrograms/kg) were determined in 12 open-chest anesthetized dogs with a partial coronary artery stenosis. 201Tl (1.5 mCi) was injected intravenously and myocardial biopsy specimens were obtained 10 min, 60 min, and 2 hr after injection. Serial changes in 201Tl activity in the normal zone and in the zone of partial stenosis were correlated with microsphere-determined regional blood flow and distal coronary pressure. Another nine dogs with equivalent stenosis not given dipyridamole before 201Tl served as controls. Data indicate that dipyridamole-induced vasodilation in the presence of a partial stenosis results in diminished uptake and delayed clearance compared with increased uptake and more rapid clearance in normally perfused myocardium producing an initial 201Tl defect with delayed redistribution

Dipyridamole-induced ST segment depression during thallium-201 imaging in patients with coronary artery disease: angiographic and hemodynamic determinants

International Nuclear Information System (INIS)

Chambers, C.E.; Brown, K.A.

1988-01-01

To examine the angiographic and hemodynamic determinants of dipyridamole-induced ST segment depression in patients with coronary artery disease, 41 patients with angiographically documented coronary disease who underwent dipyridamole-thallium-201 myocardial scintigraphy were studied. Dipyridamole-induced ST depression occurred in 14 (34%) of the 41 patients. Stepwise multivariate logistic regression was performed to compare the predictive value of angiographic findings (good coronary collateral vessels, jeopardized collateral vessels, multivessel disease), hemodynamic changes (changes in heart rate, systolic pressure, diastolic pressure and rate-pressure product), thallium-201 results (perfusion defect, thallium-201 redistribution) and demographic data (age, gender, medications). Only the presence of good coronary collateral vessels (p less than 0.02) and increases in rate-pressure product after dipyridamole infusion (p less than 0.02) were significant multivariate predictors of dipyridamole-induced ST depression. Good collateral vessels were more common in the group with ST depression (11 [79%] of 14) than they were in the group without ST depression (6 [22%] of 27; p less than 0.001). Rate-pressure product increased 2,835 +/- 1,648 beats/min.mm Hg in the group with ST depression compared with 1,179 +/- 1,417 beats/min.mm Hg in patients without ST depression (p less than 0.005). In conclusion, dipyridamole-induced ST segment depression in patients with coronary artery disease appears to be related to 1) the presence of good coronary collateral vessels, which may act by facilitating coronary steal, and 2) increases in rate-pressure product, reflecting increased myocardial oxygen demand. These observations may explain the lack of prognostic value of dipyridamole-induced ST segment depression described in previous reports

Patients with stable chronic obstructive pulmonary disease can safely undergo intravenous dipyridamole thallium-201 imaging.

Science.gov (United States)

Shaffer, J; Simbartl, L; Render, M L; Snow, E; Chaney, C; Nishiyama, H; Rauf, G C; Wexler, L F

1998-08-01

Patients with chronic obstructive pulmonary disease are usually excluded from intravenous dipyridamole thallium-201 testing. We developed a nurse-administered protocol to screen and pretreat patients so they could be safely tested. We prospectively screened patients referred for intravenous dipyridamole thallium testing and retrospectively reviewed a comparison group of patients who had undergone intravenous dipyridamole testing before our bronchospasm protocol. We studied 492 consecutive patients referred for intravenous dipyridamole thallium testing, separating those with complete data (n = 451) into two groups: group A (n = 72), patients assessed to be at risk for intravenous dipyridamole-induced bronchospasm who received our bronchospasm treatment protocol; and group B (n = 379), patients assessed to be free of risk, who did not receive our bronchospasm protocol. Group C (n = 89) was a retrospective comparison group of patients who had undergone intravenous dipyridamole testing before initiation of the protocol. Patients were considered at risk for an adverse event if any of the following were present: peak flow 400 ml after bronchodilator treatment, wheezing audible with stethoscope, history of chronic obstructive pulmonary disease or asthma or dyspnea on exertion at less than four blocks, or resting respiratory rate >18 breaths/min. The test was considered contraindicated if resting oxygen saturation was respiratory rate stethoscope but without marked respiratory distress), (2) marked events (severe bronchospasm or severe ischemia defined as wheezing audible with or without stethoscope, respiratory rate >20 breaths/min or increased by 10 from pretest evaluation, oxygen desaturation to respiratory rate with decreased mental status], respiratory arrest, chest pain, horizontal ST-segment depression > or =1 mm on the electrocardiogram in any lead, symptomatic hypotension), or (3) other intravenous dipyridamole-induced side effects (persistent headache, dizziness

Prognostic value of intravenous dipyridamole thallium imaging in patients with diabetes mellitus considered for renal transplantation

International Nuclear Information System (INIS)

Camp, A.D.; Garvin, P.J.; Hoff, J.; Marsh, J.; Byers, S.L.; Chaitman, B.R.

1990-01-01

Patients with diabetes and end-stage renal failure are known to have a high risk for cardiac morbidity and mortality associated with renal transplantation. The most efficient method to determine preoperative cardiac risk has not been established. To determine the effectiveness of intravenous dipyridamole thallium imaging in predicting cardiac events, 40 diabetic renal transplant candidates were studied preoperatively in a prospective trial. The study group consisted of 40 patients whose average age was 42 years (range 27 to 64); 34 (85%) were hypertensive and 21 (53%) were cigarette smokers. Cardiac history included chest pain in 6 patients and prior myocardial infarction in 3 patients. Dipyridamole thallium imaging showed reversible defects in 9 patients, fixed defects in 8 patients and normal scans in 23 patients. Dipyridamole thallium imaging was performed using 0.56 mg/kg of dipyridamole infused intravenously over 4 minutes. Cardiac events occurred only in patients with reversible thallium defects, of which there were 6. Of these 6 patients, 3 had cardiac events before transplantation and 3 had them in the early postoperative phase (within 6 weeks of surgery). Of 21 patients who underwent renal transplantation, 3 had cardiac events within 6 weeks of transplantation. The average duration of follow-up was 11 months (range 1 to 21). Thus, dipyridamole thallium imaging is an effective method of identifying renal transplant candidates likely to develop cardiac complications. Routine coronary angiography may not be necessary to screen all renal transplant candidates for coronary artery disease before surgery

Diagnostic value of exercise stress testing, dipyridamole stress-echocardiography and perfusion stress-scintigraphy for identification of coronary artery disease in women

International Nuclear Information System (INIS)

Debnath, S.; Tyrnovska-Kydreva, R.; Khalacheva, S.; Radoslavova, R.; Stoyanova, N.; Draganov, T.; Elenkova, A.; Garcheva, M.; Shejretova, E.

1995-01-01

To compare the value of exercise stress testing (EST), dipyridamole stress echocardiography and 99m Tc-methoxy-isobutyl-isonitrile (MIBI)-planer scintigraphy, 75 female patients with angina pectoris who underwent coronary angiography were studied. Significant (≥50% stenosis) coronary artery disease (CAD) was present in 38 of the patients. EST was performed in all of the patients but dipyridamole echocardiography and MIBI-planer scintigraphy - in 36 of them (22 with and 14 without CAD). Compared with dipyridamole echocardiography, EST and MIBI-planer scintigraphy had a significantly higher sensitivity (74% vs 45%, p<0.01 and 82% vs 45%, p<0.01, respectively). There was no significant difference in sensitivity between EST and MIBI-planer scintigraphy. Dipyridamole echocardiography and MIBI-planer scintigraphy showed a higher specificity than EST (93% vs 54%, p<0.01 and 93% vs 54%, p<0.01, respectively). Diagnostic accuracy of MIBI-planer scintigraphy was higher than that of dipyridamole echocardiography and EST (86% vs 64%, p<0.05 and 86 vs 64%, p<0.01, respectively). Thus, MIBI-planer scintigraphy appears to be superior to EST and dipyridamole echocardiography for the evaluation of CAD in symptomatic women. 20 refs., 2 tabs. (author)

Myocardial thallium scintigraphy after dipyridamole injection. Application to the diagnosis and evaluation of coronary disease

International Nuclear Information System (INIS)

Foult, J.M.; Weinmann, P.; Moretti, J.L.; Le Guludec, D.; Faraggi, M.

1992-01-01

Myocardial thallium scintigraphy performed after intravenous injection of dipyridamole is a non-invasive method to diagnose and evaluate coronary disease.It be used as an alternative to post-exercise scintigraphy, both methods having similar sensitivity and specificity. The dipyridamole test is contraindicated in patients with a history of bronchospasm and uncontrolled angina pectoris. Close clinical and electrocardiographic monitoring is required. The wide use of tomographic techniques has notably improved this examination

Dipyridamole-thallium-201 scintigraphy in the prediction of future cardiac events after acute myocardial infarction

International Nuclear Information System (INIS)

Leppo, J.A.; O'Brien, J.; Rothendler, J.A.; Getchell, J.D.; Lee, V.W.

1984-01-01

To evaluate the safety and usefulness of serial thallium scanning immediately after intravenous dipyridamole, we studied 51 patients recovering from acute myocardial infarction. Eight patients experienced angina during the procedure, but there were no serious complications. Patients were followed for a mean period of 19 months after hospital discharge. Eleven of 12 patients who died during follow-up or had another infarction had shown transient defects (redistribution) on their predischarge scan, as had 22 of the 24 patients who needed readmission for management of angina. Among all the other clinical or scintigraphic criteria tested, the presence of redistribution on the dipyridamole-thallium scan was the only significant predictor of these serious cardiac events. Twenty-six patients were also given a submaximal exercise test before discharge, of whom 13 subsequently had serious cardiac events. The exercise test had been positive in only 6 of these 13 patients, whereas the dipyridamole-thallium scan had shown a redistribution pattern in 12 (P less than 0.001). We conclude from this preliminary study that dipyridamole-thallium scintigraphy after myocardial infraction is relatively safe. It appears to be a more sensitive predictor of subsequent cardiac events than a submaximal exercise test and may therefore prove useful in evaluating patients after recovery from a myocardial infarction

Aspirin plus dipyridamole versus aspirin alone after cerebral ischaemia of arterial origin (ESPRIT): randomised controlled trial.

Science.gov (United States)

Halkes, P H A; van Gijn, J; Kappelle, L J; Koudstaal, P J; Algra, A

2006-05-20

Results of trials of aspirin and dipyridamole combined versus aspirin alone for the secondary prevention of vascular events after ischaemic stroke of presumed arterial origin are inconsistent. Our aim was to resolve this uncertainty. We did a randomised controlled trial in which we assigned patients to aspirin (30-325 mg daily) with (n=1363) or without (n=1376) dipyridamole (200 mg twice daily) within 6 months of a transient ischaemic attack or minor stroke of presumed arterial origin. Our primary outcome event was the composite of death from all vascular causes, non-fatal stroke, non-fatal myocardial infarction, or major bleeding complication, whichever happened first. Treatment was open, but auditing of outcome events was blinded. Primary analysis was by intention to treat. This study is registered as an International Standard Randomised Controlled Trial (number ISRCTN73824458) and with (NCT00161070). Mean follow-up was 3.5 years (SD 2.0). Median aspirin dose was 75 mg in both treatment groups (range 30-325); extended-release dipyridamole was used by 83% (n=1131) of patients on the combination regimen. Primary outcome events arose in 173 (13%) patients on aspirin and dipyridamole and in 216 (16%) on aspirin alone (hazard ratio 0.80, 95% CI 0.66-0.98; absolute risk reduction 1.0% per year, 95% CI 0.1-1.8). Addition of the ESPRIT data to the meta-analysis of previous trials resulted in an overall risk ratio for the composite of vascular death, stroke, or myocardial infarction of 0.82 (95% CI 0.74-0.91). Patients on aspirin and dipyridamole discontinued trial medication more often than those on aspirin alone (470 vs 184), mainly because of headache. The ESPRIT results, combined with the results of previous trials, provide sufficient evidence to prefer the combination regimen of aspirin plus dipyridamole over aspirin alone as antithrombotic therapy after cerebral ischaemia of arterial origin.

Interstitial adenosine concentration is increased by dipyridamole

International Nuclear Information System (INIS)

Gorman, M.W.; Wangler, R.D.; DeWitt, D.F.; Wang, C.Y.; Bassingthwaighte, J.B.; Sparks, H.V.

1986-01-01

The authors used the multiple indicator dilution technique to observe the capillary transport of adenosine (ADO) in isolated guinea pig hearts. Radiolabelled albumin, sucrose and ADO were injected on the arterial side and measured in venous samples collected during the following 20 seconds. Transport parameters calculated from these data include permeability-surface area products (PS) for transendothelial diffusion, endothelial cell (EC) uptake at the lumenal and ablumenal membranes, and EC metabolism. With simultaneous measurements of arterial and venous ADO concentrations and flow, the authors calculated the steady-state interstitial fluid (ISF) ADO concentration. Under control conditions the venous ADO concentration was 7.1 +/- 2.8 nM. The calculated ISF concentration depends on whether they assume the venous ADO comes from the ISF, or directly from ECs. These ISF concentrations are 25 +/- 12 nM and 9.8 +/- 4.0 nM, respectively. During dipyridamole infusion (10 uM) the EC transport parameters became nearly zero. Venous and ISF ADO concentrations increased to 33 +/- 8.9 nM and 169 +/- 42 nM, respectively. The authors conclude that the ISF ADO concentration is 1.5-4 fold higher than the venous concentration at rest, and the ISF concentration increases greatly with dipyridamole

Transient mitral regurgitation: An adjunctive sign of myocardial ischemia during dipyridamole-thallium imaging

International Nuclear Information System (INIS)

Lette, J.; Gagnon, A.; Lapointe, J.; Cerino, M.

1989-01-01

A patient developed transient exacerbation of a mitral insufficiency murmur and a reversible posterior wall perfusion defect during dipyridamole-thallium imaging. Coronary angiography showed significant stenoses of both the right and the circumflex coronary arteries that supply the posterior papillary muscle. Cardiac auscultation for transient mitral incompetence, a sign of reversible papillary muscle dysfunction, is a simple and practical adjunctive test for myocardial ischemia during dipyridamole-thallium imaging. It may confirm that an isolated reversible posterior wall myocardial perfusion defect is truly ischemic in nature as opposed to an artifact resulting from attenuation by the diaphragm

Radioprotection by dipyridamole in the aging mouse. Effects on lipid peroxidation in mouse liver, spleen and brain after whole-body X-ray irradiation

International Nuclear Information System (INIS)

Seino, Noritaka

1995-01-01

To investigate the radioprotective effect of dipyridamole in the aging mouse, the lipid peroxide content in aging mouse liver, spleen and brain irradiated by X-ray were measured both before and after injection of dipyridamole. The lipid peroxide content increased with aging from 2 months old to 16 months old in the mouse liver, spleen and brain. The content of lipid peroxide in the liver and spleen of the aging mouse was significantly increased in 7 days after whole-body irradiation with 8 Gy, but was unchanged in the brain. Dipyridamole, given before irradiation, significantly inhibited the increase of lipid peroxide after irradiation. These results suggest that dipyridamole may have radioprotective effects on aging mouse liver and spleen as well as on young mouse, and that inhibition of lipid peroxidation is a possible factor in the radioprotective effect of dipyridamole. (author)

Acute myocardial infarction associated with intravenous dipyridamole for rubidium-82 PET imaging

International Nuclear Information System (INIS)

Marwick, T.H.; Hollman, J.

1990-01-01

This report describes the occurrence of chest pain and electrocardiographic features of acute myocardial infarction following intravenous dipyridamole-handgrip stress. Myocardial perfusion imaging (Rb-82 PET) demonstrated a stress-induced perfusion defect. Following failure to respond to medical therapy, urgent cardiac catheterization demonstrated total occlusion of the left anterior descending coronary artery. The vessel was revascularized, with limitation of myocardial damage evidenced by failure to develop anterior Q waves and only modest elevation of cardiac enzyme levels. Complications of intravenous dipyridamole stress are rare, this case constituting the first major problem in over 500 such procedures at this institution. However, this experience demonstrates the importance of vigilant observation during the performance of this technique

Safety and diagnostic accuracy of dipyridamole-thallium imaging in the elderly

International Nuclear Information System (INIS)

Lam, J.Y.; Chaitman, B.R.; Glaenzer, M.; Byers, S.; Fite, J.; Shah, Y.; Goodgold, H.; Samuels, L.

1988-01-01

The noninvasive diagnosis of coronary artery disease in the elderly can occasionally be difficult. Intravenous dipyridamole-thallium imaging is a potentially useful diagnostic test to determine presence and severity of coronary disease; however, the safety of the procedure has not been determined in an older population. The side effect profile and frequency of severe ischemic responses after 0.56 mg/kg of intravenous dipyridamole were compared in 101 patients greater than or equal to 70 years old and 236 patients less than 70 years old. There were no side effects in 64% and 62% of patients greater than or equal to 70 and less than 70 years old, respectively (p = NS). Among the 337 patients tested, there were no complications of myocardial infarction or death. The most common cardiac side effect was chest pain, which occurred in 21 (21%) of the 101 patients aged greater than or equal to 70 years and in 64 (27%) of the 236 patients less than 70 years (p = NS). Aminophylline was required to reverse cardiac or noncardiac side effects in 15 (15%) and 36 (15%) of the patients greater than or equal to 70 and less than 70 years old, respectively (p = NS). A severe ischemic response occurred in 2% and 2.5% of patients greater than or equal to 70 and less than 70 years old, respectively (p = NS). The sensitivity of intravenous dipyridamole-thallium imaging for obstructive coronary artery disease was 86% (25 of 29) and 83% (68 of 82) in older and younger patients, respectively (p = NS); the specificity was 75% (6 of 8) and 70% (16 of 23), respectively (p = NS). Thus, intravenous dipyridamole-thallium imaging is a safe noninvasive method for assessment of older patients with obstructive coronary disease; its side effect profile and diagnostic accuracy are similar to those seen in younger patients. The technique is associated with severe ischemic responses in only a small minority of patients

Aspirin and extended-release dipyridamole versus clopidogrel for recurrent stroke

DEFF Research Database (Denmark)

Sacco, Ralph L; Diener, Hans-Christoph; Yusuf, Salim

2008-01-01

BACKGROUND: Recurrent stroke is a frequent, disabling event after ischemic stroke. This study compared the efficacy and safety of two antiplatelet regimens--aspirin plus extended-release dipyridamole (ASA-ERDP) versus clopidogrel. METHODS: In this double-blind, 2-by-2 factorial trial, we randomly...

Prognostic value of dipyridamole thallium scintigraphy for evaluation of ischemic heart disease

International Nuclear Information System (INIS)

Hendel, R.C.; Layden, J.J.; Leppo, J.A.

1990-01-01

Exercise testing alone or in combination with thallium scintigraphy has significant prognostic value. In contrast, dipyridamole thallium imaging is not dependent on patients achieving adequate levels of exercise, but no long-term prognostic studies have been reported. Accordingly, imaging results of 516 consecutive patients referred for dipyridamole thallium studies were correlated with subsequent cardiac events, death (n = 23) and myocardial infarction (n = 43) over a mean follow-up period of 21 months. Patients with a history of congestive heart failure, prior myocardial infarction, diabetes mellitus or abnormal scans were significantly more likely to have a cardiac event (p less than 0.03). With use of logistic regression analysis, an abnormal scan was an independent and significant predictor of subsequent myocardial infarction or cardiac death and increased the relative risk of any event more than threefold. The presence of redistribution on thallium scanning further increased the risk of a cardiac event. Survival analysis demonstrated a significant difference between patients with an abnormal or normal thallium scan over a 30 month period. In conclusion, dipyridamole thallium scintigraphy demonstrates prognostic value in a large unselected population and may be an adequate clinical alternative to physiologic exercise testing in the evaluation of coronary heart disease

Safety of intravenous dipyridamole thallium myocardial perfusion imaging: experience in 435 patients

International Nuclear Information System (INIS)

Dubrey, S.W.; Noble, M.I.M.; Jewkes, R.F.; Bomanji, J.B.

1993-01-01

Dipyridamole stress 201 T1 scintigraphy is widely used in the investigation of myocardial ischaemia. We report our experience of adverse effects observed during this diagnostic procedure. A prospective study was undertaken of 435 consecutive patients referred to two nuclear medicine departments for assessment of myocardial perfusion. Patients were monitored prior to and following the infusion of dipyridamole. All symptomatic, haemodynamic and electrocardiographic changes were documented. No deaths occurred in this series. Adverse events were observed in 174 (40%) patients. Of these, three patients experienced 'major' adverse events (0.6%) requiring hospitalization (myocardial infarction = 1; chest pain = 1; simple partial seizure = 1). 'Moderate' adverse events occurred in 39 (8.9%) patients and required intravenous aminophylline to reverse effects (ST segment abnormalities = 26; nausea = 7; headache = 3; chest pain = 2; bronchospasm = 1; protracted vomiting = 1; diarrhoea = 1). 'Minor' adverse events were experienced by 132 (30.3%) patients and did not require aminophylline. Sixty per cent of our patients experienced no ill effects from dipyridamole given as an exercise substitute in conjunction with 201 T1 imaging. The rest had symptoms which were mostly mild, although a few patients found the experience unpleasant. Only one patient experienced a life-threatening episode. (Author)

Additional diagnostic value of systolic dysfunction induced by dipyridamole stress cardiac magnetic resonance used in detecting coronary artery disease.

Science.gov (United States)

Husser, Oliver; Bodí, Vicente; Sanchís, Juan; Mainar, Luis; Núñez, Julio; López-Lereu, María P; Monmeneu, José V; Ruiz, Vicente; Rumiz, Eva; Moratal, David; Chorro, Francisco J; Llácer, Angel

2009-04-01

Dipyridamole stress perfusion cardiovascular magnetic resonance (CMR) is used to detect coronary artery disease (CAD). However, few data are available on the diagnostic value of the systolic dysfunction induced by dipyridamole. This study investigated whether the induction of systolic dysfunction supplements the diagnostic information provided by perfusion imaging in the detection of CAD. Overall, 166 patients underwent dipyridamole CMR and quantitative coronary angiography, with CAD being defined as a stenosis > or =70%. Systolic dysfunction at rest, systolic dysfunction with dipyridamole, induced systolic dysfunction, and stress first-pass perfussion deficit (PD) and delayed enhancement were quantified. In the multivariate analysis, PD (hazard ratio [HR]=1.6; 95% confidence interval [CI], 1.33-1.91;Pstatistic for predicting CAD (0.81 vs. 0.87; P=.02). Combining induced systolic dysfunction with perfusion imaging increases the diagnostic accuracy of detecting CAD and enables patients with severe ischemia and a high probability of CAD to be identified.

Changes of electrocardiogram and hemodynamics in response to dipyridamole: In vivo comparative analyses using anesthetized beagle dogs and microminipigs.

Science.gov (United States)

Ando, Kentaro; Takahara, Akira; Nakamura, Yuji; Wada, Takeshi; Chiba, Koki; Goto, Ai; Lubna, Nur Jaharat; Hagiwara-Nagasawa, Mihoko; Izumi-Nakaseko, Hiroko; Hoshiai, Kiyotaka; Akie, Yasuki; Naito, Atsuhiko T; Sugiyama, Atsushi

2018-02-01

Microminipigs are expected as a novel animal model for cardiovascular pharmacological experiments. Since inherent vulnerability of coronary circulation of microminipigs has not been characterized, we performed dipyridamole-stress test to both microminipigs and beagle dogs, and compared the results. Dipyridamole in doses of 0.056 and 0.56 mg/kg were intravenously infused over 10 min (n = 4 for each animal). Dipyridamole decreased the systolic/diastolic blood pressures and double product in dogs as well as in microminipigs; but it did not significantly alter the heart rate or the global balance between the myocardial oxygen demand and supply in either animal. While organic coronary arterial stenosis was not detected in either animal, dogs have well-developed epicardial intracoronary networks unlike microminipigs. Like in humans, dipyridamole did not affect the ST segment of microminipigs, whereas it substantially depressed that in dogs. The results indicate the onset of subendocardial ischemia by dipyridamole in dogs may be partly associated with their well-developed native coronary collateral channels. Microminipigs would be more useful to evaluate the drugs which may affect the coronary circulation in the pre-clinical study than dogs. Copyright © 2018 The Authors. Production and hosting by Elsevier B.V. All rights reserved.

Quantitative thallium-201 scintigraphy after dipyridamole infusion combined with low level exercise in healthy volunteers

International Nuclear Information System (INIS)

Laarman, G.J.; Niemeyer, M.G.; Ascoop, C.A.P.L.; Bruschke, A.V.G.; Wall, E.E. van der; Verzijlbergen, F.J.; Liam Go, T.

1989-01-01

To establish test specific normal limits for quantitative analysis of uptake and washout of 201 Tl after dipyridamole infusion combined with low level exercise, 20 healthy volunteers were studied with low likelihood of coronary artery disease (CAD) assessed by a stepwise probability analysis based on age, sex, symptoms, resting electrocardiogram, and exercise electrocardiography. Likelihood of CAD in these volunteers was calculated as ≤ 1%. After dipyridamole infusion combined with low level exercise, one volunteer complained of headache; no other side effects were observed. There were no chest pain complaints. Maximal hemodynamic changes were achieved during the 6th and 7th min of the test. No ST segment depression was recorded. Visual analysis of the 201 Tl scintigrams was normal in all volunteers. Mean regional washout at 4 h was 44.37%±2.11%. The regional washout in the 70 0 LAO view (46.65%±1.10%) was significantly higher than in the anterior and 30 0 LAO views (43.44%±1.50% and 43.02%±1.45%, respectively). Profiles of uptake and washout of 201 Tl were different after dipyridamole infusion combined with low level exercise as compared to maximal exercise. Thus, in quantitative analysis of 201 Tl scintigraphy after dipyridamole infusion in conjunction with low level exercise as applied in the present study, it is mandatory to use normal limits of uptake and washout of 201 Tl derived from healthy volunteers who underwent the same combined protocol. (orig.)

Effect of surfactants, gastric emptying, and dosage form on supersaturation of dipyridamole in an in vitro model simulating the stomach and duodenum.

Science.gov (United States)

Mitra, A; Fadda, H M

2014-08-04

The purpose of this study was to investigate the influence of gastric emptying patterns, surfactants, and dosage form on the supersaturation of a poorly soluble weakly basic drug, dipyridamole, using an in vitro model mimicking the dynamic environment of the upper gastrointestinal tract, and, furthermore, to evaluate the usefulness of this model in establishing correlations to in vivo bioavailability for drugs with solubility/dissolution limited absorption. A simulated stomach duodenum model comprising four compartments was used to assess supersaturation and precipitation kinetics as a function of time. It integrates physiologically relevant fluid volumes, fluid transfer rates, and pH changes of the upper GI tract. Monoexponential gastric emptying patterns simulating the fasted state were compared to linear gastric emptying patterns simulating the fed state. The effect of different surfactants commonly used in oral preparations, specifically, sodium lauryl sulfate (SLS), poloxamer-188, and polysorbate-80, on dipyridamole supersaturation was investigated while maintaining surface tension of the simulated gastric fluids at physiological levels and without obtaining artificial micellar solubilization of the drug. The supersaturation behavior of different dose strengths of dipyridamole was explored. Significant levels of dipyridamole supersaturation were observed in the duodenal compartment under all the different in vivo relevant conditions explored. Dipyridamole supersaturation ratios of up to 11-fold have been observed, and supersaturation has been maintained for up to 120 min. Lower duodenal concentrations of dipyridamole were observed under linear gastric emptying patterns compared to mononexponential gastric emptying. The mean duodenal area under concentration-time curves (AUC60min) for the dipyridamole concentration profile in the duodenal compartment is significantly different for all the surfactants explored (P stomach duodenum model can provide a reliable and

ECG-manifest and ECG-silent dipyridamole technetium-99m sestamibi SPET perfusion defects in patients with ischaemic heart disease

International Nuclear Information System (INIS)

Galli, M.; Marcassa, C.; Bosimini, E.; Zoccarato, O.; Comazzi, F.; Giannuzzi, P.

1997-01-01

To investigate the relationship between ECG changes and perfusion abnormalities, body surface maps were recorded during dipyridamole infusion in 55 subjects (11 normals and 44 patients with ischaemic heart disease) undergoing dipyridamole technetium-99m sestamibi single-photon emission tomography (SPET). All had a normal resting ECG. The extent and severity of the sestamibi defect were quantified. New negative areas in the isointegral maps and rest-dipyridamole map differences >2 SD from normal limits were considered abnormal. After dipyridamole in normals, neither perfusion defects nor ≥1 mm ST segment depression on 12-lead ECG nor new negative areas in isointegral maps occurred. In patients, dipyridamole induced new perfusion defects in 35 (80%) but ST segment depression in only 18 (41%, P<0.001). Of the 35 patients with perfusion defects, 17 (49%, group 1) showed ST segment depression, while the other 18 (51%, group 2) did not. Abnormal body surface maps were found in 100% of group 1 and 88% of group 2 patients (NS). In group 1, the provoked hypoperfusion was of greater extent (P=0.007) and severity (P=0.01) and the onset of map abnormalities was significantly earlier (P<0.001) than in group 2; time to map abnormalities was also significantly shorter than time to ST segment depression (P=0.01). In the 35 patients with complete scintigraphic, body map and angiographic data, the severity of reversible perfusion defect proved to be the strongest correlate of ST segment depression upon logistic regression analysis. Thus, sestamibi SPET abnormalities after dipyridamole are almost always associated with electrical changes on body surface maps, suggesting myocardial ischaemia as their cause. The much less common 12-lead ECG changes are slower to appear and reflect a more severe hypoperfusion. (orig./MG). With 5 figs., 4 tabs

Effects of dipyridamole and aminophylline on hemodynamics, regional myocardial blood flow and thallium-201 washout in the setting of a critical coronary stenosis

International Nuclear Information System (INIS)

Granato, J.E.; Watson, D.D.; Belardinelli, L.; Cannon, J.M.; Beller, G.A.

1990-01-01

Experiments were performed to characterize the interaction of intravenous dipyridamole and aminophylline on thallium-201 transport kinetics, regional myocardial blood flow and systemic hemodynamics in the presence of a critical coronary artery stenosis. In 12 dogs with a critical left anterior descending coronary artery stenosis, arterial pressure decreased from a mean value (+/- SEM) of 107 +/- 6 to 94 +/- 3 mm Hg and distal left anterior descending artery pressure decreased from 70 +/- 7 to 55 +/- 4 mm Hg after intravenous administration of dipyridamole. In the left anterior descending perfusion zone, the endocardial/epicardial flow ratio decreased from 0.70 to 0.36 and the intrinsic thallium washout rate was significantly prolonged. Intravenous aminophylline reversed the dipyridamole-induced systemic hypotension and transmural coronary steal and restored the thallium washout rate to baseline values. In six other dogs, aminophylline alone resulted in no alterations in systemic and coronary hemodynamics or regional myocardial blood flow. As expected, dipyridamole-induced vasodilation and coronary steal were prevented by aminophylline pretreatment. These data show that in a canine model of partial coronary stenosis, systemic hypotension, adverse regional flow effects and prolonged thallium-201 washout consequent to intravenously administered dipyridamole are promptly reversed by intravenous aminophylline administration. Aminophylline alone had no significant hemodynamic and coronary flow effects. This study provides further insight into the altered thallium kinetics occurring as a consequence of dipyridamole-induced vasodilation and suggests that the prompt reversal of symptoms and signs of ischemia with aminophylline in patients receiving intravenous dipyridamole for clinical imaging studies probably reflects the reversal of transmural coronary steal

In Vitro Dissolution of Fluconazole and Dipyridamole in Gastrointestinal Simulator (GIS), Predicting in Vivo Dissolution and Drug-Drug Interaction Caused by Acid-Reducing Agents.

Science.gov (United States)

Matsui, Kazuki; Tsume, Yasuhiro; Amidon, Gregory E; Amidon, Gordon L

2015-07-06

Weakly basic drugs typically exhibit pH-dependent solubility in the physiological pH range, displaying supersaturation or precipitation along the gastrointestinal tract. Additionally, their oral bioavailabilities may be affected by coadministration of acid-reducing agents that elevate gastric pH. The purpose of this study was to assess the feasibility of a multicompartmental in vitro dissolution apparatus, Gastrointestinal Simulator (GIS), in predicting in vivo dissolution of certain oral medications. In vitro dissolution studies of fluconazole, a BCS class I, and dipyridamole, a BCS class II weak bases (class IIb), were performed in the GIS as well as United States Pharmacopeia (USP) apparatus II and compared with the results of clinical drug-drug interaction (DDI) studies. In both USP apparatus II and GIS, fluconazole completely dissolved within 60 min regardless of pH, reflecting no DDI between fluconazole and acid-reducing agents in a clinical study. On the other hand, seven-fold and 15-fold higher concentrations of dipyridamole than saturation solubility were observed in the intestinal compartments in GIS with gastric pH 2.0. Precipitation of dipyridamole was also observed in the GIS, and the percentage of dipyridamole in solution was 45.2 ± 7.0%. In GIS with gastric pH 6.0, mimicking the coadministration of acid-reducing agents, the concentration of dipyridamole was equal to its saturation solubility, and the percentage of drug in solution was 9.3 ± 2.7%. These results are consistent with the clinical DDI study of dipyridamole with famotidine, which significantly reduced the Cmax and area under the curve. An In situ mouse infusion study combined with GIS revealed that high concentration of dipyridamole in the GIS enhanced oral drug absorption, which confirmed the supersaturation of dipyridamole. In conclusion, GIS was shown to be a useful apparatus to predict in vivo dissolution for BCS class IIb drugs.

Diagnostic value of transient dilatation of the left ventricle in negative dipyridamole-thallium imaging

International Nuclear Information System (INIS)

Seo, Hiromi; Doi, Y.L.; Yonezawa, Yoshihiro; Chikamori, Taishiro; Yamada, Mitsutoshi; Ozawa, Toshio

1994-01-01

To evaluate the diagnostic value of a transient dilatation of the left ventricle during dipyridamole-thallium imaging (DTI) for detecting significant coronary artery disease (CAD) in patients with negative DTI results, 81 consecutive patients were studied. Twenty one patients (26%) had CAD and 60 patients had normal coronary anatomy (NCA). The initial/delayed ratio of the left ventricular dimension, which was measured as the distance between the 2 peaks of a count profile curve on a 45deg left anterior oblique planar image, was defined as the dilatation ratio (DR) of the left ventricle. Patients with CAD had a higher incidence of chest pain after dipyridamole infusion (35 vs 13%; p 1.03) when it was greater than the mean +2 standard deviations of the DR in NCA patients. Seventy-six percent of CAD patients had an abnormal DR. A stepwise discriminant analysis revealed that an abnormal DR alone had the same ability to predict CAD (sensitivity 76%, specificity 98%, chi-square 80.9, p 1.03) is a highly specific marker for detecting CAD, even in patients with negative dipyridamole-thallium imaging. (author)

Noninvasive identification of left main and triple vessel coronary artery disease using dipyridamole thallium scintigraphy

International Nuclear Information System (INIS)

Chikamori, Taishiro; Doi, Yoshinori; Yonezawa, Yoshihiro; Yamada, Mitsutoshi; Seo, Hiromi; Kawai, Kazuya; Yabe, Toshikazu; Ozawa, Toshio

1993-01-01

The diagnostic value of dipyridamole thallium scintigraphy for the noninvasive identification of left main (LM) and triple vessel (TV) coronary artery disease (CAD) was evaluated in 615 consecutive patients with known or suspected CAD. One hundred thirty-nine patients had LM or TVCAD; the remaining 476 patients had limited CAD (double vessel CAD in 112, single vessel CAD in 235, insignificant lesions in 129). Patients with LM or TVCAD, compared to those with limited CAD, had a higher incidence of diffuse slow washout (58 vs 20%, p<0.0001), extensive fixed defects (21 vs 6%, p<0.0001) and extensive reversible defects (32 vs 8%, p<0.0001). During dipyridamole loading, the incidence of chest pain was higher (65 vs 41%, p<0.0001), and the magnitude of ST depression was greater (0.16±0.14 vs 0.04±0.07 mV, p<0.001) in patients with LM or TVCAD than in those with limited CAD. Stepwise discriminant analysis using scintigraphic imaging achieved a sensitivity of 69%, a specificity of 79%, and an accuracy of 77% for diagnosing patients with LM or TVCAD. After including clinical markers of ischemia during dipyridamole loading, multivariate analysis revealed an improved diagnosis with a sensitivity of 71%, a specificity of 85%, and an accuracy of 82%. These results clearly show the usefulness of scintigraphic imaging as well as the significance of careful assessment of clinical markers of ischemia during dipyridamole loading for the noninvasive identification of LM and TVCAD. (author)

Serial thallium-201 imaging after dipyridamole for coronary disease detection: quantitative analysis using myocardial clearance

International Nuclear Information System (INIS)

Okada, R.D.; Dai, Y.H.; Boucher, C.A.; Pohost, G.M.

1984-01-01

After dipyridamole, canine studies have demonstrated a slower rate of myocardial thallium-201 clearance from zones distal to a coronary artery stenosis compared to normal zones. To determine if criteria based on canine myocardial thallium-201 clearance rates could be applied clinically, 40 patients with and 26 patients without coronary artery disease (CAD) had serial thallium-201 images obtained for 2 to 5 hours after dipyridamole. Regions of interest were manually placed over six left ventricular segments in two projections for each of three imaging times. The myocardial thallium-201 clearance rate was calculated for each of the six segments and, using the clearance rate criterion found in canine studies, was considered abnormal if less than 6.5%/hr. Using this criterion alone, 22 of 26 patients (85%) without CAD had normal and 30 of 40 patients (75%) with CAD had abnormal myocardial thallium-201 clearance rates. A quantitative analysis of regional inhomogeneity in tracer distribution (normal was greater than or equal to 25% difference between segments) was negative in 24 of 26 patients (92%) without CAD and positive in 20 of 40 patients (50%) with CAD. When both clearance rate and regional inhomogeneity were considered, 21 of 26 patients (81%) without CAD had negative and 36 of 40 patients (90%) with CAD had positive results. Thus, post-dipyridamole myocardial clearance rate criteria derived from canine studies can be applied to clinical thallium imaging. Quantitative analysis of serial thallium-201 images after dipyridamole is optimized by using myocardial thallium-201 clearance rates. Such an approach is independent of regional inhomogeneities in tracer distribution

New Exercise-Dipyridamole Combined Test for Nuclear Cardiology in Insufficient Effort: Appropriate Diagnostic Sensitivity Keeping Exercise Prognosis

Energy Technology Data Exchange (ETDEWEB)

Cortinas, Inés Vidal, E-mail: invi@montevideo.com.uy; Beretta, Mario; Alonso, Omar; Mut, Fernando [Departamento de Medicina Nuclear do Hospital ‘Asociación Española’, Br. Artigas 1515, Montevideo (Uruguay)

2015-08-15

Myocardial perfusion scintigraphy (MPS) in patients not reaching 85% of the maximum predicted heart rate (MPHR) has reduced sensitivity. In an attempt to maintain diagnostic sensitivity without losing functional exercise data, a new exercise and dipyridamole combined protocol (EDCP) was developed. Our aim was to evaluate the feasibility and safety of this protocol and to compare its diagnostic sensitivity against standard exercise and dipyridamole protocols. In patients not reaching a sufficient exercise (SE) test and with no contraindications, 0.56 mg/kg of dipyridamole were IV administered over 1 minute simultaneously with exercise, followed by 99mTc-MIBI injection. Of 155 patients, 41 had MPS with EDCP, 47 had a SE test (≥ 85% MPHR) and 67 underwent the dipyridamole alone test (DIP). They all underwent coronary angiography within 3 months. The three stress methods for diagnosis of coronary lesions had their sensitivity compared. For stenosis ≥ 70%, EDCP yielded 97% sensitivity, SE 90% and DIP 95% (p = 0.43). For lesions ≥ 50%, the sensitivities were 94%, 88% and 95%, respectively (p = 0.35). Side effects of EDCP were present in only 12% of the patients, significantly less than with DIP (p < 0.001). The proposed combined protocol is a valid and safe method that yields adequate diagnostic sensitivity, keeping exercise prognostic information in patients unable to reach target heart rate, with fewer side effects than the DIP.

Predictive value of quantitative dipyridamole-thallium scintigraphy in assessing cardiovascular risk after vascular surgery in diabetes mellitus

International Nuclear Information System (INIS)

Lane, S.E.; Lewis, S.M.; Pippin, J.J.; Kosinski, E.J.; Campbell, D.; Nesto, R.W.; Hill, T.

1989-01-01

Cardiac complications represent a major risk to patients undergoing vascular surgery. Diabetic patients may be particularly prone to such complications due to the high incidence of concomitant coronary artery disease, the severity of which may be clinically unrecognized. Attempts to stratify groups by clinical criteria have been useful but lack the predictive value of currently used noninvasive techniques such as dipyridamole-thallium scintigraphy. One hundred one diabetic patients were evaluated with dipyridamole-thallium scintigraphy before undergoing vascular surgery. The incidence of thallium abnormalities was high (80%) and did not correlate with clinical markers of coronary disease. Even in a subgroup of patients with no overt clinical evidence of underlying heart disease, thallium abnormalities were present in 59%. Cardiovascular complications, however, occurred in only 11% of all patients. Statistically significant prediction of risk was not achieved with simple assessment of thallium results as normal or abnormal. Quantification of total number of reversible defects, as well as assessment of ischemia in the distribution of the left anterior descending coronary artery was required for optimum predictive accuracy. The prevalence of dipyridamole-thallium abnormalities in a diabetic population is much higher than that reported in nondiabetic patients and cannot be predicted by usual clinical indicators of heart disease. In addition, cardiovascular risk of vascular surgery can be optimally assessed by quantitative analysis of dipyridamole-thallium scintigraphy and identification of high- and low-risk subgroups

Dipyridamole-thallium scanning in patients undergoing vascular surgery. Optimizing preoperative evaluation of cardiac risk

International Nuclear Information System (INIS)

Eagle, K.A.; Singer, D.E.; Brewster, D.C.; Darling, R.C.; Mulley, A.G.; Boucher, C.A.

1987-01-01

Dipyridamole-thallium imaging has been suggested as a method of preoperatively assessing cardiac risk in patients undergoing major surgery. To define more clearly its proper role in preoperative assessment, we prospectively evaluated 111 patients undergoing vascular surgery. In the first set of 61 patients, our data confirmed the value of preoperative dipyridamole-thallium scanning in identifying the patients who suffered postoperative ischemic events. Events occurred in eight of 18 patients with reversible defects on preoperative imaging, compared with no events in 43 patients with no thallium redistribution (confidence interval for the risk difference: 0.624, 0.256). The results also suggested that clinical factors might allow identification of a low-risk subset of patients. To test the hypothesis that patients with no evidence of congestive heart failure, angina, prior myocardial infarction, or diabetes do not require further preoperative testing, we evaluated an additional 50 patients having vascular procedures. None of the 23 without the clinical markers had untoward outcomes, while ten of 27 patients with one or more of these clinical markers suffered postoperative ischemic events (confidence interval for the risk difference: 0.592, 0.148). In the clinical high-risk subset, further risk stratification is achieved with dipyridamole-thallium scanning

Noninvasive identification of significant narrowing of the left main coronary artery by dipyridamole thallium scintigraphy

International Nuclear Information System (INIS)

Chikamori, T.; Doi, Y.L.; Yonezawa, Y.; Yamada, M.; Seo, H.; Ozawa, T.

1991-01-01

To evaluate the usefulness of dipyridamole thallium scintigraphy with low-level exercise for the identification of left main (LM) coronary artery disease (CAD), 466 consecutive patients with CAD were studied. Thirty-eight patients (8%) had LM stenosis (diameter narrowing greater than or equal to 50%). The LM scintigraphic pattern was present in 9 of 38 patients with LMCAD and 38 of 428 CAD patients without LMCAD (24 vs 9%; p less than 0.005). This pattern was present in 6 of 9 patients with LMCAD without right CAD and in only 3 of 29 patients with LM and right CAD (67 vs 10%; p = 0.0005). Patients with LMCAD had a higher incidence of premature cessation of low-level exercise (53 vs 21%; p less than 0.0001), chest pain (68 vs 48%; p less than 0.02), blood pressure decrease of greater than or equal to 20 mm Hg (44 vs 16%; p less than 0.002) and greater ST depression (0.17 ± 0.13 vs 0.06 ± 0.10 mV; p less than 0.001) during dipyridamole loading than patients without LMCAD. Stepwise discriminant analysis revealed that the LM scintigraphic pattern and markers of ischemia during dipyridamole loading best identified (p less than 0.0001) patients with LMCAD without right CAD (sensitivity 67%, specificity 91%), but this predictability is no better than the LM scintigraphic pattern alone. The combination of clinical markers of ischemia during dipyridamole loading and scintigraphic findings of diffuse slow washout, extensive fixed defects and the LM pattern best identified (p less than 0.0001) patients with LM and right CAD (sensitivity 72%, specificity 80%)

ESPRIT: is aspirin plus dipyridamole superior to aspirin alone in TIA or minor stroke patients?

Science.gov (United States)

Rouhl, R P W; Lodder, J

2008-11-01

Transient ischemic attack (TIA) or a (minor) ischemic stroke increases the risk of a recurrent stroke or death. Antiplatelet therapy with aspirin or clopidogrel is, in the absence of a potential cardiac embolic source, common practice to lower this risk. Until recently, adjuvant dipyridamole or low intensity oral anticoagulation were not generally prescribed in secondary prevention. In this article, we will summarize and discuss the published results of the European/Australasian Stroke Prevention in Reversible Ischemia Trial (ESPRIT). In this trial, treatments with anticoagulants, aspirin alone and the combination of aspirin plus dipyridamole were compared, in a multicenter, three-armed, randomized, open-label study in patients with TIA or minor stroke.

Usefulness of semiquantitative analysis of dipyridamole-thallium-201 redistribution for improving risk stratification before vascular surgery

International Nuclear Information System (INIS)

Levinson, J.R.; Boucher, C.A.; Coley, C.M.; Guiney, T.E.; Strauss, H.W.; Eagle, K.A.

1990-01-01

Preoperative dipyridamole-thallium-201 scanning is sensitive in identifying patients prone to ischemic cardiac complications after vascular surgery, but most patients with redistribution do not have an event after surgery. Therefore, its positive predictive value is limited. To determine which patients with thallium redistribution are at highest risk, dipyridamole-thallium-201 images were interpreted semiquantitatively. Sixty-two consecutive patients with redistribution on preoperative dipyridamole-thallium-201 planar imaging studies were identified. Each thallium scan was then analyzed independently by 2 observers for the number of myocardial segments out of 15, the number of thallium views out of 3 and the number of coronary artery territories with redistribution. Seventeen patients (27%) had postoperative ischemic events, including unstable angina pectoris, ischemic pulmonary edema, myocardial infarction and cardiac death. Thallium predictors of ischemic operative complications included thallium redistribution greater than or equal to 4 myocardial segments (p = 0.03), greater than or equal to 2 of the 3 planar views (p = 0.005) and greater than or equal to 2 coronary territories (p = 0.007). No patient with redistribution in only 1 view had an ischemic event (0 of 15). Thus, determining the extent of redistribution by dipyridamole-thallium-201 scanning improves risk stratification before vascular surgery. Patients with greater numbers of myocardial segments and greater numbers of coronary territories showing thallium-201 redistribution are at higher risk for ischemic cardiac complications. In contrast, when the extent of thallium redistribution is limited, there is a lower risk despite the presence of redistribution

New Exercise-Dipyridamole Combined Test for Nuclear Cardiology in Insufficient Effort: Appropriate Diagnostic Sensitivity Keeping Exercise Prognosis

Directory of Open Access Journals (Sweden)

Inés Vidal Cortinas

2015-08-01

Full Text Available AbstractBackground:Myocardial perfusion scintigraphy (MPS in patients not reaching 85% of the maximum predicted heart rate (MPHR has reduced sensitivity.Objectives:In an attempt to maintain diagnostic sensitivity without losing functional exercise data, a new exercise and dipyridamole combined protocol (EDCP was developed. Our aim was to evaluate the feasibility and safety of this protocol and to compare its diagnostic sensitivity against standard exercise and dipyridamole protocols.Methods:In patients not reaching a sufficient exercise (SE test and with no contraindications, 0.56 mg/kg of dipyridamole were IV administered over 1 minute simultaneously with exercise, followed by 99mTc-MIBI injection.Results:Of 155 patients, 41 had MPS with EDCP, 47 had a SE test (≥ 85% MPHR and 67 underwent the dipyridamole alone test (DIP. They all underwent coronary angiography within 3 months. The three stress methods for diagnosis of coronary lesions had their sensitivity compared. For stenosis ≥ 70%, EDCP yielded 97% sensitivity, SE 90% and DIP 95% (p = 0.43. For lesions ≥ 50%, the sensitivities were 94%, 88% and 95%, respectively (p = 0.35. Side effects of EDCP were present in only 12% of the patients, significantly less than with DIP (p < 0.001.Conclusions:The proposed combined protocol is a valid and safe method that yields adequate diagnostic sensitivity, keeping exercise prognostic information in patients unable to reach target heart rate, with fewer side effects than the DIP.

The safety of dipyridamole myocardial perfusion scintigraphy (MPS) in patients with end-stage chronic airways limitations (CAL)

International Nuclear Information System (INIS)

Roman, M.R.; Freeman, A.P.; Angelides, S.

2000-01-01

Full text: Dipyridamole MPS is a well-established investigative technique in the diagnosis and pre-operative risk stratification of patients with possible coronary artery disease. However, there remains a concern of its use in patients with end-stage chronic airways limitations (CAL). Lung volume reduction surgery (LVRS) is a recent therapeutic option for such patients. The options for non-invasive pre-operative cardiac assessment in such patients are limited. This study reviewed the safety of dipyridamole use in such a clinical setting. 20 patients (10M, 10F, mean age 64.8 yrs) were evaluated. None had any history of ischaemic heart disease. Dipyridamole was administered intravenously at a dose of 0.05 mg/kg. Six patients remained asymptomatic throughout the procedure, while none experienced any chest pain. Two patients experienced moderate dyspnoea, which was rapidly relieved with aminophylline (100mg IV) during the recovery phase of the study. Two others developed mild dyspnoea; one settled spontaneously, while the other responded promptly to aminophylline. Aminophylline was administered to nine other patients to reverse minor symptoms (headache, flushing sensation). One other patient developed marked hypotension (SBP fell >20mmHg) and bradycardia, but no ECG changes for myocardial ischaemia. He responded well to aminophylline. His myocardial perfusion scan demonstrated extensive reversible myocardial ischaemia. Although the population size was small, dipyridamole appears safe to use in patients with end-stage CAL. Copyright (2000) The Australian and New Zealand Society of Nuclear Medicine Inc

Reduction of indium-111 platelet deposition on Dacron vascular grafts in humans by aspirin plus dipyridamole

International Nuclear Information System (INIS)

Stratton, J.R.; Ritchie, J.L.

1986-01-01

Aspirin plus dipyridamole reduces platelet accumulation on short-term Dacron vascular grafts in man. To determine whether drug inhibition of platelet deposition is sustained on older grafts, we studied 18 men aged 41 to 87 years who had Dacron aortic bifurcation grafts in place a mean of 43.4 months (range 9.8 to 121.0) before and during short-term therapy with aspirin (325 mg tid) plus dipyridamole (75 mg tid). During both the baseline and drug studies, indium-111 ( 111 In) platelet deposition was quantitated by two techniques, standard planar imaging performed at 24, 48, and 72 hr after injection of platelets and single photon emission computed tomographic imaging performed at 24 and 72 hr after injection. All analyses were performed in a blinded fashion. On both the planar and tomographic images, platelet accumulation on the graft was quantitated by a graft/blood ratio that compared activity in the graft to simultaneously collected whole blood 111 In platelet activity. Aspirin plus dipyridamole reduced the tomographic graft/blood ratio at 24 hr (20.6 +/- 3.5 vs 17.3 +/- 2.5) (+/-SEM) and at 72 hr (29.0 +/- 4.8 vs 25.0 +/- 4.1) after injection of platelets (p = .02). Dacron vascular grafts. Similarly, the planar graft/blood ratio was reduced at 24 hr (2.7 +/- 0.5 vs 2.4 +/- 0.5), 48 hr (3.7 +/- 0.9 vs 3.1 +/- 0.7), and 72 hr (4.0 +/- 0.9 vs 3.6 +/- 0.8) (p = .04). We conclude that aspirin (325 mg tid) plus dipyridamole (75 mg tid) reduces platelet accumulation on long-term Dacron vascular grafts

The possible protective effects of dipyridamole on ischemic reperfusion injury of priapism

Directory of Open Access Journals (Sweden)

Ersagun Karaguzel

2016-02-01

Full Text Available ABSTRACT Purpose To investigate the protective effects against ischemia reperfusion injury of dipyridamole in a model of induced priapism in rats. Materials and Methods Twenty-four male Sprague-Dawley rats were divided into four groups, control, P/R, P/R+DMSO and P/R+D. 3ml blood specimens were collected from vena cava inferior in order to determine serum MDA, IMA, TAS, TOS and OSI values, and penile tissue was taken for histopathological examination in control group. Priapism was induced in P/R group. After 1h, priapism was concluded and 30 min reperfusion was performed. In P/R+DMSO group 1ml/kg DMSO was administered intraperitoneally 30 min before reperfusion, while in P/R+D group 10mg/kg dipyridamole was administered intraperitoneally 30 min before reperfusion. Blood and penis specimens were collected after the end of 30 min reperfusion period. Sinusoidal area (µm2, tears in tunica albuginea and injury parameters in sinusoidal endothelium of penis were investigated. Results Histopathological examination revealed no significant changes in term of sinusoidal area. A decrease in tears was observed in P/R+D group compared to P/R group (p0.05. There were no significant differences in MDA and IMA values between groups. A significant increase in TOS and OSI values was observed in P/R+D group compared to P/R group. A significant decrease in TAS levels was observed in P/R+D group compared to the P/R group. Conclusions The administration of dipyridamole before reperfusion in ischemic priapism model has a potential protective effect against histopathological injury of the penis.

Comparison of dipyridamole-echocardiography with dipyridamole-thallium scintigraphy for the diagnosis of myocardial ischemia

International Nuclear Information System (INIS)

Perin, E.C.; Moore, W.; Blume, M.; Hernandez, G.; Dhekne, R.; DeCastro, C.M.

1991-01-01

After an intravenous infusion of dipyridamole (0.56 mg/kg), the authors performed both echocardiography and thallium scintigraphy in 63 patients who were referred for known or suspected coronary artery disease. Of those patients, 25 returned for coronary arteriography within 1 month after the tests, thus forming the study group for this report. Sensitivity for detection of coronary artery disease, when analyzed region-by-region, was 80% for thallium scintigraphy and 57% for echocardiography, whereas specificity was 85% and 98%, respectively. When evaluating individual patients for the presence or absence of ischemia, they found a sensitivity of 95% for scintigraphy and 58% for echocardiography; corresponding specificities were 50% and 100%. By using arteriography as the gold standard for comparison, it appears that thallium scintigraphy has a significantly higher sensitivity but lower specificity for the detection of coronary artery disease than does echocardiography. Echocardiography may, however, be a useful adjunct to thallium scintigraphy in the evaluation of patients with coronary artery disease

Enhanced ex vivo inhibition of platelet function following addition of dipyridamole to aspirin after transient ischaemic attack or ischaemic stroke: first results from the TRinity AntiPlatelet responsiveness (TrAP) study.

LENUS (Irish Health Repository)

Tobin, William Oliver

2012-02-01

Ex vivo dipyridamole \\'non-responsiveness\\' has not been extensively studied in ischaemic cerebrovascular disease. Platelet surface marker expression, leucocyte-platelet complex formation and inhibition of platelet function at high shear stress as detected by the PFA-100(R) Collagen-Adenosine-diphosphate (C-ADP) and Collagen-Epinephrine cartridges was assessed in 52 patients within 4 weeks of transient ischaemic attack (TIA) or ischaemic stroke on aspirin, and then 14 d (14 d) and >90 d (90 d) after adding dipyridamole. A novel definition of \\'Dipyridamole non-responsiveness\\' was used. The median C-ADP closure time increased following addition of dipyridamole, remained elevated at 90 d (P <\\/= 0.03), and was unaffected by aspirin dose. 59% at 14 d and 56% at 90 d were \\'dipyridamole non-responders\\' on the PFA-100. The proportion of non-responders at 14 and 90 d was similar (P= 0.9). Compared with baseline (4.6%), median monocyte-platelet complexes increased at 14 d (5.0%, P= 0.03) and 90 d (4.9%, P= 0.04). Low C-ADP closure times were associated with increased monocyte-platelet complexes at 14 d (r= -0.32, P= 0.02) and 90 d (r= -0.33, P = 0.02). Monocyte-platelet complexes increased in the subgroup of dipyridamole non-responders on the PFA-100 (P<\\/= 0.045), but not in responders (P >\\/= 0.5), at 14 and 90 d versus baseline. Additional inhibition of platelet function has been detected with the PFA-100 when dipyridamole is added to aspirin. Elevated monocyte-platelet complexes may contribute to ex vivo dipyridamole non-responsiveness.

Diagnosis and prognosis of elderly patients with coronary artery disease. Assessment with dipyridamole thallium imaging

International Nuclear Information System (INIS)

Yamasaki, Fumiyasu; Takata, Jun; Seo, Hiromi; Chikamori, Taishiro; Yamada, Mitsutoshi; Yabe, Toshikazu; Doi, Yoshinori

1995-01-01

The diagnostic and prognostic value of dipyridamole perfusion scintigraphy was assessed in 147 patients with coronary artery disease aged 65 years and older. All patients underwent coronary angiography. Dipyridamole perfusion scintigraphy was performed safely in all patients. Multiple regression analysis showed that fixed defect and reversible defect were powerful detectors of coronary lesions, all patients with fixed disease and 94% of patients with only reversible defects had significant coronary lesion. Diffuse slow washout and ST depression were statistically significant for detection multivessel coronary lesions in patients with fixed disease, the sensitivity and specificity of diffuse slow washout and/or ST depression for detecting multivessel coronary lesions were 85% and 74%, respectively. Cox survival analysis identified diffuse slow washout as the best predictor of future cardiac events among the scintigraphic variables. Univariate analysis showed the best predictors were age (≥70), diffuse slow washout, and severe coronary lesions. Multivariate analysis showed diffuse slow washout and severe coronary lesions were the best predictors. Dividing the patients by age (≥70) showed that age and diffuse slow washout were good predictors. Scintigraphic and angiographic parameters found diffuse slow washout was the only good predictor. Dipyridamole perfusion scintigraphy is useful for the noninvasive detection of significant coronary artery disease in the elderly, and for predicting future cardiac events with similar predictability to angiographic findings. (S.Y.)

Dose titration to reduce dipyridamole-related headache.

Science.gov (United States)

Chang, Yeu-Jhy; Ryu, Shan-Jin; Lee, Tsong-Hai

2006-01-01

Combination of low-dose aspirin and modified-release dipyridamole (ASA+MR-DP) provides a significantly increased benefit in stroke prevention over aspirin alone. However, headaches were reported in more patients receiving dipyridamole-containing agents than in those receiving placebo. We undertook a randomized, double-blind, placebo-controlled trial to evaluate which dosing regimens of ASA+MR-DP have better tolerance. This trial randomized 146 patients with a history of ischemic cerebrovascular disease into three groups: placebo (days 1-28), reduced dose (placebo on days 1-4, ASA+MR-DP once daily before bed during days 5-14, and b.i.d. on days 15-28), and regular dose (placebo on days 1-4, and ASA+MR-DP b.i.d. on days 5-28). Using Chinese diary card, headache was assessed as mean cumulated headache (Sigma frequency x intensity/occurrence days x study days) over the study period, and was graded 0-4 according to Cancer Therapy Evaluation Program, Common Toxicity Criteria, Version 2.0. Intent-to-treat patients after randomization was 46 in placebo group, 45, reduced dose, and 49, regular dose. Among commonly reported adverse effects, headache of any grade occurred significantly more in the regular dose group (38.8%), as compared to the other two groups (p < 0.05). Mean cumulated headache was higher (p < 0.05) in the regular dose group than in the reduced group during days 5-14. Of 27 patients who dropped out, 15 (55.6%) were due to headache, which was substantially more in regular dose (8, 53.3%), though the difference was statistically insignificant. Initial reduced dose treatment with ASA+MR-DP may cause fewer headaches than regular dosing, and seems better tolerated by those susceptible to phosphodiesterase inhibitor-induced headache. Copyright 2006 S. Karger AG, Basel.

Significance of increased lung thallium-201 activity on serial cardiac images after dipyridamole treatment in coronary heart disease

International Nuclear Information System (INIS)

Okada, R.D.; Dai, Y.H.; Boucher, C.A.; Pohost, G.M.

1984-01-01

Increased lung thallium-201 (Tl-201) activity occurs in patients with severe coronary artery disease (CAD) on initial postexercise images. To determine the significance of assessing lung Tl-201 on serial imaging after dipyridamole therapy, initial and delayed (2 to 3 hours) Tl-201 imaging was performed in 40 patients with CAD and 26 normal control subjects. Lung Tl-201 activity was quantitated as a percentage of maximal myocardial activity for each imaging time (lung Tl-201 index). The mean initial lung Tl-201 activity was 42 +/- 2% (+/- standard error of the mean) in 26 control subjects, 56 +/- 2% in 25 patients with 2- or 3-vessel CAD (p less than 0.001) and 53 +/- 2% in 15 patients with 1-vessel CAD (p less than 0.005 compared with control subjects) (difference not significant between 1-vessel and multivessel CAD). Dipyridamole lung Tl-201 activity decreased relative to the myocardium from initial to delayed images (p less than 0.001) in patients with CAD but not in control subjects. When a dipyridamole lung Tl-201 index of 58% (mean +/- 2 standard deviations for control subjects) was chosen as the upper limit of normal, 14 of 40 of the CAD patients (35%) had abnormal values and all control patients had values within normal limits. These 14 patients with CAD and abnormal initial lung Tl-201 indexes had rest ejection fractions that were not significantly different from those in patients with CAD, and normal initial dipyridamole lung Tl-201 index (58 +/- 4% and 63 +/- 2%, respectively)

Prevalence and correlates of increased lung/heart ratio of thallium-201 during dipyridamole stress imaging for suspected coronary artery disease

International Nuclear Information System (INIS)

Villanueva, F.S.; Kaul, S.; Smith, W.H.; Watson, D.D.; Varma, S.K.; Beller, G.A.

1990-01-01

There is little information concerning the prevalence and clinical correlates of increased pulmonary thallium-201 uptake during dipyridamole thallium-201 stress imaging. Accordingly, the clinical characteristics and quantitative thallium-201 findings were correlated with quantitative lung/heart thallium-201 ratio in 87 patients undergoing dipyridamole thallium-201 stress testing. Nineteen patients (22%) had an elevated ratio (greater than 0.51). These patients were more likely to have had an infarction, to be taking beta blockers, and have a lower rate-pressure product after dipyridamole administration than those with a normal ratio (p less than 0.03). An elevated ratio was associated with a greater likelihood of initial, redistribution and persistent defects, as well as left ventricular cavity dilatation on thallium-201 imaging (p less than 0.05). In addition, the number of myocardial segments demonstrating initial, redistribution and persistent defects was also greater in patients with increased ratios (p less than 0.03). Multivariate analysis demonstrated that the presence of redistribution and left ventricular cavity dilatation were the most significant correlates of lung/heart thallium-201 ratio. It is concluded that the prevalence of increased lung/heart thallium-201 ratio with dipyridamole thallium-201 stress imaging is similar to that seen with exercise stress imaging. As with exercise thallium-201 imaging, increased pulmonary thallium-201 uptake may be a marker of functionally more significant coronary artery disease

Myocardial scintigraphy with 16 123I hexadecene-9 oic acid. Study of the influence of isoproterenol, propranolol, dipyridamole and isoptine

International Nuclear Information System (INIS)

Comet, M.; Wolf, J.E.; Pilichowski, P.; Busquet, G.; Dubois, F.; Mathieu, J.P.; Pernin, C.; Riche, F.; Vidal, M.

1983-01-01

After I.V. injection of 123 I hexadecene-9 oic acid to dogs, the decreasing part of the myocardial activity curve is fitted with an exponential which period is calculated. Tacking the anesthetized dogs as his own reference, we study the influence of isoproterenol, propranolol, dipyridamole and isoptine on value of the period. None of the drugs modify significatively the period. Nevertheless, propranolol and isoptine and to a lesser extent dipyridamole have a tendancy to increase the value of the period [fr

Myocardial rest iodine-123-β-methyl-iodophenyl-pentadecanoic acid scintigraphy compared with dipyridamole stress thallium-201 scintigraphy in unstable angina

International Nuclear Information System (INIS)

Misumi, Ikuo; Kimura, Yoshihiro; Hokamura, Youichi; Yamabe, Hiroshige; Ueno, Kazuhiro

1998-01-01

Twelve patients with stable angina and 12 patients with unstable angina underwent rest iodine-123-β-methyl-iodophenyl-pentadecanoic acid (BMIPP), dipyridamole stress thallium scintigraphy and delayed thallium scintigraphy. In stable angina, sensitivity for detecting ischemic segments was higher in dipyridamole thallium (74%) than rest BMIPP (48%) images (p<0.05), but there was no significant difference between the 2 images in unstable angina. In unstable angina, the incidence of segments with higher defect scores on BMIPP images than on delayed thallium images and the opposite pattern was 27 and 5 (p<0.01). In stable angina, there was no difference. The mean defect score on BMIPP (6.3±5.6) was higher than that on delayed thallium scintigraphy (2.9±2.7) and it was almost the same as on the initial dipyridamole stress test (6.5±5.2). In conclusion, BMIPP scintigraphy is safer and may be as useful in detecting myocardial ischemia in patients with unstable angina as thallium scintigraphy. (author)

Dipyridamole Body Surface Potential Mapping: Noninvasive Differentiation of Syndrome X from Coronary Artery Disease

Czech Academy of Sciences Publication Activity Database

Boudík, F.; Anger, Z.; Aschermann, M.; Vojáček, J.; Tomečková, Marie

2002-01-01

Roč. 35, č. 3 (2002), s. 181-191 ISSN 0022-0736 R&D Projects: GA MZd IZ4038 Keywords : body surface potential mapping * dipyridamole * coronary artery disease * syndrome X Subject RIV: BD - Theory of Information Impact factor: 0.599, year: 2002

Relationship between regional myocardial blood flow and thallium-201 distribution in the presence of coronary artery stenosis and dipyridamole-induced vasodilation

International Nuclear Information System (INIS)

Mays, A.E. Jr.; Cobb, F.R.

1984-01-01

This study assesses the relationship between the distribution of thallium-201 and myocardial blood flow during coronary vasodilation induced by intravenous dipyridamole in canine models of partial and complete coronary artery stenosis. 10 dogs were chronically instrumented with catheters in the left atrium and aorta and with a balloon occluder and electromagnetic flow probe on the proximal left circumflex coronary artery. Regional myocardial blood flow was measured during control conditions with radioisotope-labeled microspheres, and the phasic reactive hyperemic response to a 20-s transient occlusion was then recorded. Dipyridamole was then infused intravenously until phasic coronary blood flow increased to match peak hyperemic values. The left circumflex coronary artery was either partially occluded to reduce phasic blood flow to control values (group 1) or it was completely occluded (group 2), and thallium-201 and a second microsphere label were injected. 5 min later, the animals were sacrificed, the left ventricle was sectioned into 1-2-g samples, and thallium-201 activity and regional myocardial blood flow were measured. Curvilinear regression analyses between thallium-201 localization and myocardial blood flow during dipyridamole infusion demonstrated a slightly better fit to a second- as compared with a first-order model, indicating a slight roll-off of thallium activity as myocardial blood flow increases. During the dipyridamole infusion, the increases in phasic blood flow, the distributions of regional myocardial blood flow, and the relationships between thallium-201 localization and regional blood flow were comparable to values previously observed in exercising dogs with similar occlusions. These data provide basic validation that supports the use of intravenous dipyridamole and thallium-201 as an alternative to exercise stress and thallium-201 for evaluating the effects of coronary occlusive lesions on the distribution of regional myocardial blood flow

Significance of dipyridamole-induced transient dilation of the left ventricle during thallium-201 scintigraphy in suspected coronary artery disease

International Nuclear Information System (INIS)

Chouraqui, P.; Rodrigues, E.A.; Berman, D.S.; Maddahi, J.

1990-01-01

The occurrence and significance of transient dilation of the left ventricle during dipyridamole stress-redistribution thallium-201 scintigraphy was studied in 73 patients who underwent both dipyridamole thallium-201 study and coronary angiography. Transient dilation ratio was calculated from planar anterior images by dividing the computer-derived left ventricular area on the initial image by that of the 4-hour image. In 11 patients with normal coronary arteriograms or less than 50% coronary stenosis, the transient dilation ratio was 0.98 +/- 0.046. An abnormal transient dilation ratio was defined as greater than or equal to 1.12, representing greater than or equal to 3 standard deviations above the mean normal value. When the 15 patients with an abnormal ratio were compared with the 58 with a normal ratio, the former group had a significantly higher frequency of 3 critical (greater than or equal to 90%) coronary stenoses (33 vs 5%), higher prevalence of collaterals (67 vs 24%), more extensive myocardial reversible defects by planar (71 vs 10%) or by single-photon emission computed tomography (87.5 vs 35%) imaging and a higher incidence of dipyridamole-induced anginal chest pain (53 vs 22%). No significant difference between the 2 groups was noted with respect to age, gender, prior myocardial infarction, single or double critical coronary stenosis, dipyridamole-induced ischemic electrocardiographic response and increased lung uptake. An abnormal transient dilation ratio of greater than or equal to 1.12 was a specific marker of multivessel (87%) or 3-vessel (85%) critical coronary artery disease

The safety of dipyridamole in patients undergoing myocardial perfusion scintigraphy prior to lung volume reduction surgery

International Nuclear Information System (INIS)

Roman, M.R.; Angelides, S.; Parker, M.K.; Silva, I. da; Freeman, A.P.

2001-01-01

Patients with end-stage chronic obstructive pulmonary disease (COPD) undergoing lung volume reduction surgery (LVRS) are at high risk of peri-operative cardiac complications, and myocardial perfusion scintigraphy (MPS) is commonly used for risk stratification. This study prospectively assessed the safety of dipyridamole in these patients and compared the incidence of side-effects (particularly dyspnoea) with that in patients undergoing dipyridamole MPS prior to elective non-cardiothoracic surgery. Fifty patients were enrolled: 25 in the LVRS cohort (13 males, 12 females), with a mean age of 65 years and a mean FEV 1 of 0.79 l, and 25 (with no history of asthma or COPD) in the control cohort (14 males, 11 females), with a mean age of 66 years. Fourteen patients (56%) in each group developed side-effects. Dyspnoea was reported by five patients (20%) in the LVRS and two patients (8%) in the control cohort (P=NS). One patient in each cohort developed severe hypotension and bradycardia. Eight (32%) other patients developed minor side-effects in the LVRS cohort compared with 11 (44%) in the control group. All side-effects responded promptly to intravenous aminophylline. In summary, there was a statistically non-significant increase in the incidence of dyspnoea in patients with end-stage COPD and all side-effects responded to aminophylline. Thus, dipyridamole can be used safely in these patients. (orig.)

Myocardial scintigraphy with 16 /sup 123/I hexadecene-9 oic acid. Study of the influence of isoproterenol, propranolol, dipyridamole and isoptine

Energy Technology Data Exchange (ETDEWEB)

Comet, M.; Wolf, J.E.; Pilichowski, P.; Busquet, G.; Dubois, F.; Mathieu, J.P.; Pernin, C.; Riche, F.; Vidal, M. ( Grenoble Universite, 38 - (France))

1983-01-01

After I.V. injection of /sup 123/I hexadecene-9 oic acid to dogs, the decreasing part of the myocardial activity curve is fitted with an exponential which period is calculated. Taking the anesthetized dog as reference, we study the influence of isoproterenol, propranolol, dipyridamole and isoptine on value of the period. None of the drugs modify significantly the period. Nevertheless, propranolol and isoptine and to a lesser extent dipyridamole have a tendancy to increase the value of the period.

Synergism between dipyridamole and cisplatin in human breast cancer cells in vitro

Directory of Open Access Journals (Sweden)

Janice R. Perussi

2003-05-01

Full Text Available Cisplatin is very effective in the treatment of metastatic breast cancer. However, the development of cellular resistance is a serious problem in cisplatin chemotherapy. In the present work, the effects of dipyridamole (DPM on the cellular accumulation and cytotoxicity of cisplatin was studied in cisplatinsensitive (MDA/S and cisplatinresistant (MDA/R human breast cancer cells. In the presence of 30 µM DPM, the IC50 of cisplatin was reduced by 39% for both cell lines. Combination index analysis revealed that cisplatin and dipyridamole interact synergistically in MDA/R cells. In the MDA/S cells, the cellular accumulation of cisplatin increased by 57 ± 8% in the presence of 30 µM DPM. In the MDA/R cells, the cellular accumulation of cisplatin remained the same with or without 30 µM DPM. The results suggest that the enhancement of cisplatin cytotoxicity by DPM in MDA/S cells may be related to a DPM-induced increase in cisplatin accumulation, but the enhanced cytotoxicity in MDA/R cells employs a mechanism that does not involve an increase in the cellular accumulation of cisplatin.

In vivo quantitation of platelet deposition on human peripheral arterial bypass grafts using indium-111-labeled platelets. Effect of dipyridamole and aspirin

International Nuclear Information System (INIS)

Pumphrey, C.W.; Chesebro, J.H.; Dewanjee, M.K.; Wahner, H.W.; Hollier, L.H.; Pairolero, P.C.; Fuster, V.

1983-01-01

Indium-111-labeled autologous platelets, injected 48 hours after operation, were used to evaluate the thrombogenicity of prosthetic material and the effect of platelet inhibitor therapy in vivo. Dacron double-velour (Microvel) aortofemoral artery bifurcation grafts were placed in 16 patients and unilateral polytetrafluoroethylene femoropopliteal grafts were placed in 10 patients. Half the patients in each group received platelet inhibitors before operation (dipyridamole, 100 mg 4 times a day) and after operation (dipyridamole, 75 mg, and acetylsalicylic acid, 325 mg 3 times a day); the rest of the patients served as control subjects. Five-minute scintigrams of the graft region were taken with a gamma camera interfaced with a computer 48, 72, and 96 hours after injection of the labeled platelets. Platelet deposition was estimated from the radioactivities of the grafts and expressed as counts per 100 pixels per microcurie injected. Dipyridamole and aspirin therapy significantly reduced the number of platelets deposited on Dacron grafts and prevented platelet accumulation over 3 days. With the small amount of platelet deposition on polytetrafluoroethylene femoropopliteal artery grafts even in control patients, platelet inhibitor therapy had no demonstrable effect on platelet deposition on these grafts. It is concluded that (1) platelet deposition on vascular grafts in vivo can be quantitated by noninvasive methods, and (2) dipyridamole and aspirin therapy reduced platelet deposition on Dacron aortofemoral artery grafts

Nuclear Scan Strategy and Outcomes in Chest Pain Patients Value of Stress Testing with Dipyridamole or Adenosine

International Nuclear Information System (INIS)

Conti, Alberto; Mariannini, Yuri; Canuti, Erica; Petrova, Tetyana; Innocenti, Francesca; Zanobetti, Maurizio; Gallini, Chiara; Costanzo, Egidio

2014-01-01

To update the prognostic value of scan strategy with pharmacological stress agent in chest pain (CP) patients presenting with normal electrocardiography (ECG) and troponin. Two consecutive nonrandomized series of patients with CP and negative first-line workup inclusive of serial ECG, serial troponin, and echocardiography underwent myocardial perfusion imaging single photon emission computed tomography (SPECT) in the emergency department. Of 170 patients enrolled, 52 patients underwent dipyridamole-SPECT and 118 adenosine-SPECT. Patients with perfusion defects underwent angiography, whereas the remaining patients were discharged and followed-up. Primary endpoint was the composite of nonfatal myocardial infarction, unstable angina, revascularization, and cardiovascular death at follow-up or the presence of coronary stenosis > 50% at angiography. At multivariate analysis, the presence of perfusion defects or hypertension was independent predictor of the primary endpoint. Sensitivity and negative predictive value were higher in patients subjected to adenosine-SPECT (95% and 99%, respectively) versus dipyridamole-SPECT (56% and 89%; yield 70% and 11%, respectively; P < 0.03). Of note, sensitivity, negative, and positive predictive values were high in patients with hypertension (100%, 93%, and 60%, respectively) or nonischemic echocardiography alterations (100%, 100%, and 100%, respectively). In CP patients, presenting with normal ECG and troponin, adenosine-SPECT adds incremental prognostic values to dipyridamole-SPECT. Costly scan strategy is more appropriate and avoids unnecessary angiograms in patients with hypertension or nonischemic echocardiography alterations

Diagnostic value for coronary artery disease of ST depression and chest pain during dipyridamole loading

International Nuclear Information System (INIS)

Yonezawa, Yoshihiro; Doi, Yoshinori; Aono, Tadashi; Odawara, Hiroaki; Chikamori, Taishiro; Yamada, Mitsutoshi; Takata, Jun; Ozawa, Toshio; Hamashige, Naohisa.

1991-01-01

The diagnostic significance of both ST depression and chest pain during dipyridamole loading was assessed in 437 patients with coronary artery disease (CRD) who have received dipyridamole-loading thallium-201 myocardial scintigraphy and coronary arteriography. ST depression and chest pain were induced in 35% and 42%, respectively. ST depression occurred in 23% for one vessel disease, 55% for two-vessel disease, 67% for three-vessel disease, and 11% for non-significant disease. In the absence of myocardial infarction, it occurred in as many as 78% for two-vessel disease and 94% for three-vessel disease. ST depression had a sensitivity of 51% and a specificity of 89%. Chest pain had a lower specificity (77%), whereas the sensitivity remained the same (51%). In 42 (31%) of 134 patients with ST depression, coronary revascularization was necessary in the early stage. With a median follow up of 29 months, 3 patients (2%) died of cardiac events, and 12 (9%) had nonfatal cardiac complications. There was a significant correlation between reversible defects (RD) on myocardial scintigrams and ST depression; RD were seen in 81% of ST depression cases, and ST depression occurred in 51% of 210 RD cases. The more diseased vessels, the more frequently ST depression occurred in accordance with RD on myocardial scintigrams. Both ST depression and chest pain during dipyridamole loading tended to be associated with myocardial ischemia, suggesting the diagnostic value in CRD patients with limited exercise loading. RD on myocardial scintigrams was considered attributable to coronary steal phenomenon for multi-vessel disease and to the difference in the relative increase of the coronary flow for single vessel disease. (N.K.)

Applying preoperative dipyridamole thallium-201 scintigraphy for preventing cardiac mortality and complications for patients with secondary hyperparathyroidism undergoing parathyroidectomy

Directory of Open Access Journals (Sweden)

Shih-min Yin

2018-05-01

Full Text Available Summary: Background: To evaluate the value of preoperative dipyridamole thallium-201 scintigraphy for reducing cardiovascular complication in secondary hyperparathyroidism (SHPTH patients. Methods: Thallium scintigraphy was arranged for all dialysis patients who underwent parathyroidectomy from Jan 2011 to July 2015. Management of defects on thallium scintigraphy included cardiac catheterization and ultrasonography. Analysis includes 30-day mortality, morbidity and the predicting factors for thallium scintigraphy defect. Results: Of 249 patients with SHPTH, 19 (7.6% had defects on thallium scintigraphy, 15 (88% of whom had coronary artery disease on angiography. History of acute coronary syndrome (ACS, p < 0.001, diabetes mellitus (DM, p = 0.03, male sex (p = 0.03, and higher body mass index (BMI, p = 0.001 were significant predictors of positive thallium scintigraphy results. History of ACS was the most significant predictor after adjustment in the multivariate logistic analysis (odds ratio, 22.56; 95% confidence interval, 7.02–72.53. All the patients survived the 30-day postoperative period, with minimal cardiovascular morbidity. Conclusion: Preoperative dipyridamole thallium-201 scintigraphy is useful for SHPTH patients to minimized surgical mortality and morbidity. Keywords: Secondary hyperparathyroidism, Dialysis, Coronary artery disease (CAD, Dipyridamole thallium-201 scintigraphy

Dipyridamole 201T1 myocardial perfusion tomography and bull's--eye analysis for quantitative evaluation of CAD

International Nuclear Information System (INIS)

Jiang Maosong; Tang Xi

1992-01-01

To assess the ability of quantitative analysis of dipyridamole 201 T1 tomography for detecting and localizing coronary artery disease (CAD), 55 patients with angiographically proved CAD ( = 50% stenosis) were studied. All patients underwent dipyridamole 201 T1 myocardial perfusion tomography and coronary arteriography. The overall sensitivity for detection of CAD by Bull's-eye analysis was 89% (50 patients) and 92% (51 patients) with visual analysis. The sensitivity for detecting individual vessel involvement with the Bull'-eye analysis was 88% for LAD. 81% for RCA and 67% for LCX. With visual analysis, the results were 88%, 83% and 58% respectively. The overall rate of detection was 87% in lesions greater than or equal to 75% stenosis vs 59% in those under 75% stenosis (P 201 T1 tomography using Bull's-eye display is a highly accurate reproducible technique for the detection of patients with CAD and the localization of individual coronary vessel, and it offers the potential to quantify the percentage of the abnormally perfused myocardium

Head-to-head comparison of dipyridamole, dobutamine and pacing stress echocardiography for the detection of myocardial ischemia in an animal model of coronary artery stenosis

Directory of Open Access Journals (Sweden)

A. Schmidt

2001-07-01

Full Text Available To compare the sensitivity of dipyridamole, dobutamine and pacing stress echocardiography for the detection of myocardial ischemia we produced a physiologically significant stenosis in the left circumflex artery of 14 open-chest dogs (range: 50 to 89% reduction in luminal diameter. In each study, dobutamine (5 to 40 µg kg-1 min-1 in 3-min stages and pacing (20 bpm increments, each 2 min, up to 260 bpm were performed randomly, and then followed by dipyridamole (up to 0.84 mg/kg over 10 min. The positivity of stress echocardiography tests was quantitatively determined by a significant (P<0.05 reduction of or failure to increase absolute and percent systolic wall thickening in the stenotic artery supplied wall, as compared to the opposite wall (areas related to the left anterior descending artery. Systolic and diastolic frozen images were analyzed off-line by two blinded observers in the control and stress conditions. The results showed that 1 the sensitivity of dobutamine, dipyridamole and pacing stress tests was 57, 57 and 36%, respectively; 2 in animals with positive tests, the mean percent change of wall thickening in left ventricular ischemic segments was larger in the pacing (-19 ± 11% and dipyridamole (-18 ± 16% tests as compared to dobutamine (-9 ± 6% (P = 0.05, but a similar mean reduction of wall thickening was observed when this variable was normalized to a control left ventricular segment (area related to the left anterior descending artery (pacing: -16 ± 7%; dipyridamole: -25 ± 16%; dobutamine: -26 ± 10%; not significant, and 3 a significant correlation was observed between magnitude of coronary stenosis and left ventricular segmental dysfunction induced by ischemia in dogs submitted to positive stress tests. We conclude that the dobutamine and dipyridamole stress tests showed identical sensitivities for the detection of myocardial ischemia in this one-vessel disease animal model with a wide range of left circumflex artery

Dipyridamole thallium-201 single-photon emission tomography in aortic stenosis: gender differences

International Nuclear Information System (INIS)

Rask, L.P.; Karp, K.H.; Eriksson, N.P.; Mooe, T.

1995-01-01

This study was undertaken to establish the gender-specific normal limits of thallium-201 distribution in patients with aortic stenosis and to apply these normal limits in a larger group of patients with aortic stenosis to obtain the sensitivity and specificity for coexisting CAD. A low-dose dipyridamole protocol was used (0.56 mg/kg during 4 min). Thallium was injected 2 min later and tomographic imaging was performed. Following image reconstruction a basal, a mid-ventricular and an apical short-axis slice were selected. The highest activity in each 6 segment was normalised to the maximal activity of each slice. The normal uptake for patients with aortic stenosis was obtained from ten men and ten women with aortic stenosis and a normal coronary angiography. Eighty-nine patients were prospectively evaluated. An area reduction of at least 75% in a coronary artery was considered to be a significant coronary lesion and was found in 57 (64%) patients. With gender-specific curves (-2.5 SD) sensitivity for detecting CAD was 100% and specificity was 75% in men, while sensitivity was 61% and specificity 64% in women. It is concluded that the gender-specific normal distribution of 201 Tl uptake in patients with aortic stenosis, using dipyridamole SPET, yields a high sensitivity and specificity for coronary artery lesions in men but a lower sensitivity and specificity in women with aortic stenosis. (orig./MG)

Myocardial viability in cases with persistent perfusion defects on the dipyridamole thallium-201 scintigram. A comparative study with autopsy findings

International Nuclear Information System (INIS)

Nakayama, Masafumi; Mashima, Saburo; Ohkawa, Shin-ichiro; Tanno, Munehiko; Yamada, Hideo.

1996-01-01

The aim of this study was to assess the incidence of myocardial infarction among persistent perfusion defects in dipyridamole-stress thallium scintigraphy by inspecting autopsied hearts and to evaluate whether the regional thallium activity of a scintigraphic defect can predict the presence of infarction. Autopsied hearts were compared with dipyridamole myocardial scintigrams undertaken during life in 27 patients (mean age 85±8 years). The time interval from stress testing until death was 428±351 days. Regional thallium uptake of delayed perfusion defect was calculated on the short axis images. The grade of regional myocardial fibrosis in autopsy specimens was also quantified to correlate with the corresponding regional thallium uptake. In 6 of 15 (40%) regions with persistent defects on the scintigram, myocardial infarction was not found at autopsy. Regional thallium-201 uptake of delayed defects < 50% diagnosed infarction with a sensitivity of 82% and a specificity of 80%. A linear correlation (r=-0.67) was observed between percent thallium-201 uptake and the degree of myocardial fibrosis. In conclusion, perfusion defects at 4-hour imaging in dipyridamole-stress testing may overestimate the presence of myocardial infarction and regional thallium-201 activity is helpful in distinguishing between defects with and without infarction. (author)

Serial thallium-201 myocardial imaging after dipyridamole infusion: diagnostic utility in detecting coronary stenoses and relationship to regional wall motion

International Nuclear Information System (INIS)

Leppo, J.; Boucher, C.A.; Okada, R.D.; Newell, J.B.; Strauss, H.W.; Pohost, G.M.

1982-01-01

After a 4-minute i.v. dipyridamole infusion, 0.14 mg/kg/min, serial thallium-201 scans were obtained in 60 patients undergoing cardia catheterization. Forty patients had significant (greater than or equal to50% stenosis) coronary artery disease (CAD), and 20 patients had normal coronary arteries or trivial lesions. The images were graded qualitatively for thallium activity by three observers. Sensitivity was 93% (37 of 40) and specificity was 80% (16 of 20). The sensitivity and specificity of the thallium-201 study were not affected by the extent of CAD, the presence of Q waves, or propranolol therapy. Twenty-seven of 37 patients who had initial defects (73%) had complete thallium redistribution of one or more defects. Patient-by-patient anlaysis using a regression model of all patients showed that the fate of a segmental thallium defect predicted abnormal wall motion by angiography better than ECG Q waves. The presence of propranolol therapy or collaterals did not significantly affect the thallium redistribution results. It is concluded that qualitative interpretation by multiple observers of thallium images after dipyridamole infusion is a highly sensitive and specific test for CAD. After dipyridamole, as with exercise stress, the extent of thallium redistribution is related to the degree of myocardial wall motion abnormality

Comparison of early exercise treadmill test and oral dipyridamole thallium-201 tomography for the identification of jeopardized myocardium in patients receiving thrombolytic therapy for acute Q-wave myocardial infarction

International Nuclear Information System (INIS)

Jain, A.; Hicks, R.R.; Frantz, D.M.; Myers, G.H.; Rowe, M.W.

1990-01-01

Thrombolytic therapy has become the treatment of choice for patients with acute myocardial infarction. Researchers are not yet able to identify patients with salvage of myocardium who are at risk for recurrent coronary events. Thus, a prospective trial was performed in 46 patients with myocardial infarction (28 anterior and 18 inferior) who received thrombolytic therapy to determine if early thallium tomography (4.7 days) using oral dipyridamole would identify more patients with residual ischemia than early symptom-limited exercise treadmill tests (5.5 days). There were no complications during the exercise treadmill tests or oral dipyridamole thallium tomography. Mean duration of exercise was 11 +/- 3 minutes and the peak heart rate was 126 beats/min. Thirteen patients had positive test results. After oral dipyridamole all patients had abnormal thallium uptake on the early images. Positive scans with partial filling in of the initial perfusion defects were evident in 34 patients. Angina developed in 13 patients and was easily reversed with intravenous aminophylline. Both symptom-limited exercise treadmill tests and thallium tomography using oral dipyridamole were safely performed early after myocardial infarction in patients receiving thrombolytic therapy. Thallium tomography identified more patients with residual ischemia than exercise treadmill tests (74 vs 28%). Further studies are required to determine whether the results of thallium tomography after oral dipyridamole can be used to optimize patient management and eliminate the need for coronary angiography in some patients

Low-dose and high-dose acetylsalicylic acid, with and without dipyridamole: a review of clinical trial results

NARCIS (Netherlands)

Tijssen, J. G.

1998-01-01

Publication of the results of the second European Stroke Prevention Study (ESPS-2) provided the incentive for an update of the meta-analyses of aspirin and dipyridamole in the secondary prevention of stroke. After review of published randomized trials of prolonged treatment with aspirin,

Dipyridamole stress myocardial perfusion by computed tomography in patients with left bundle branch block

OpenAIRE

Cabeda, Est?van Vieira; Falc?o, Andr?a Maria Gomes; Soares Jr., Jos?; Rochitte, Carlos Eduardo; Nomura, C?sar Higa; ?vila, Luiz Francisco Rodrigues; Parga, Jos? Rodrigues

2015-01-01

Abstract Background: Functional tests have limited accuracy for identifying myocardial ischemia in patients with left bundle branch block (LBBB). Objective: To assess the diagnostic accuracy of dipyridamole-stress myocardial computed tomography perfusion (CTP) by 320-detector CT in patients with LBBB using invasive quantitative coronary angiography (QCA) (stenosis ≥ 70%) as reference; to investigate the advantage of adding CTP to coronary computed tomography angiography (CTA) and comp...

Comparison of dobutamine-stress magnetic resonance imaging and dipyridamole-Tl-201-SPECT as alternative strategies for the detection of coronary artery disease in patients not suitable for stress-echocardiography

International Nuclear Information System (INIS)

Schmidt, M.; Theissen, P.; Voth, E.; Schicha, H.; Jochims, M.; Baer, F.M.; Crnac, J.; Schneider, C.A.; Erdmann, E.

2001-01-01

Aim: During the past decade stress-echocardiography has gained increasing popularity for detection of myocardial ischemia in patients with coronary artery disease. However, about 10% to 15% of the patients submitted for stress-echocardiography do not have an adequate acoustic window. The purpose of this study was to compare high-dose dobutamine-stress magnetic resonance imaging (dobutamine-MRI) with dipyridamole-Tl-201-SPECT (dipyridamole-SPECT) as alternative strategies for detection of myocardial ischemia in patients with inadequate image quality by stress-echocardiography. Patients and Methods: Of 296 patients which were consecutively submitted to stress-echo-cardiography 45 patients (15%) had two or more segments that could not be evaluated according to the 16-segment-model of the American Society of Echocardiography. They underwent dobutamine-MRI and dipyridamole-SPECT studies, which were evaluated using a 28-segment modell. Myocardial segments were attributed to perfusion territories of the coronary arteries. The results of ischemia detection were compared to the results of coronary angiography (stenosis ≥50%). Results: In comparison to coronary angiography dobutamine-MRI yielded a sensitivity of 87%, a specificity of 86%, a positive predictive value of 93%, a negative predictive value of 75% and a diagnostic accuracy of 86%. For dipyridamole-SPECT results were 90%, 86%, 93%, 80% and 89%, respectively. These values were not significantly different. Conclusions: In patients not suitable for stress-echocardiography, both dobutamine-MRI and dipyridamole-SPECT are reliable strategies for detection of myocardial ischemia. Selection is dependent on the patient criteria, technical considerations, local logistics and experience of the observer. (orig.) [de

Antiplatelet therapy with aspirin, clopidogrel, and dipyridamole versus clopidogrel alone or aspirin and dipyridamole in patients with acute cerebral ischaemia (TARDIS)

DEFF Research Database (Denmark)

Bath, Philip M; Woodhouse, Lisa J; Appleton, Jason P

2018-01-01

, and dipyridamole) with that of guideline-based antiplatelet therapy. METHODS: We did an international, prospective, randomised, open-label, blinded-endpoint trial in adult participants with ischaemic stroke or transient ischaemic attack (TIA) within 48 h of onset. Participants were assigned in a 1:1 ratio using...... was stratified by country and index event, and minimised with prognostic baseline factors, medication use, time to randomisation, stroke-related factors, and thrombolysis. The ordinal primary outcome was the combined incidence and severity of any recurrent stroke (ischaemic or haemorrhagic; assessed using...... therapy group, 1540 in the guideline antiplatelet therapy group) were recruited from 106 hospitals in four countries between April 7, 2009, and March 18, 2016. The trial was stopped early on the recommendation of the data monitoring committee. The incidence and severity of recurrent stroke or TIA did...

Determination of cardiac risk by dipyridamole-thallium imaging before peripheral vascular surgery

International Nuclear Information System (INIS)

Boucher, C.A.; Brewster, D.C.; Darling, R.C.; Okada, R.D.; Strauss, H.W.; Pohost, G.M.

1985-01-01

To evaluate the severity of coronary artery disease in patients with severe peripheral vascular disease requiring surgery, preoperative dipyridamole-thallium imaging was performed in 54 stable patients with suspected coronary artery disease. Of the 54 patients, 48 had peripheral vascular surgery as scheduled without coronary angiography, of whom 8 (17 per cent) had postoperative cardiac ischemic events. The occurrence of these eight cardiac events could not have been predicted preoperatively by any clinical factors but did correlate with the presence of thallium redistribution. Eight of 16 patients with thallium redistribution had cardiac events, whereas there were no such events in 32 patients whose thallium scan either was normal or showed only persistent defects (P less than 0.0001). Six other patients also had thallium redistribution but underwent coronary angiography before vascular surgery. All had severe multivessel coronary artery disease, and four underwent coronary bypass surgery followed by uncomplicated peripheral vascular surgery. These data suggest that patients without thallium redistribution are at a low risk for postoperative ischemic events and may proceed to have vascular surgery. Patients with redistribution have a high incidence of postoperative ischemic events and should be considered for preoperative coronary angiography and myocardial revascularization in an effort to avoid postoperative myocardial ischemia and to improve survival. Dipyridamole-thallium imaging is superior to clinical assessment and is safer and less expensive than coronary angiography for the determination of cardiac risk

Dipyridamole thallium-201 single-photon emission tomography in aortic stenosis: gender differences

Energy Technology Data Exchange (ETDEWEB)

Rask, L P [Dept. of Clinical Physiology, Univ. Hospital of Northern Sweden, Umeaa (Sweden); [Dept. of Cardiology, Univ. Hospital of Northern Sweden, Umeaa (Sweden); Karp, K H [Dept. of Clinical Physiology, Univ. Hospital of Northern Sweden, Umeaa (Sweden); Eriksson, N P [Dept. of Radiology, Univ. Hospital of Northern Sweden, Umeaa (Spain); [Dept. of Cardiology, Univ. Hospital of Northern Sweden, Umeaa (Sweden); Mooe, T [Dept. of Cardiology, Univ. Hospital of Northern Sweden, Umeaa (Sweden)

1995-10-01

This study was undertaken to establish the gender-specific normal limits of thallium-201 distribution in patients with aortic stenosis and to apply these normal limits in a larger group of patients with aortic stenosis to obtain the sensitivity and specificity for coexisting CAD. A low-dose dipyridamole protocol was used (0.56 mg/kg during 4 min). Thallium was injected 2 min later and tomographic imaging was performed. Following image reconstruction a basal, a mid-ventricular and an apical short-axis slice were selected. The highest activity in each 6 segment was normalised to the maximal activity of each slice. The normal uptake for patients with aortic stenosis was obtained from ten men and ten women with aortic stenosis and a normal coronary angiography. Eighty-nine patients were prospectively evaluated. An area reduction of at least 75% in a coronary artery was considered to be a significant coronary lesion and was found in 57 (64%) patients. With gender-specific curves (-2.5 SD) sensitivity for detecting CAD was 100% and specificity was 75% in men, while sensitivity was 61% and specificity 64% in women. It is concluded that the gender-specific normal distribution of {sup 201}Tl uptake in patients with aortic stenosis, using dipyridamole SPET, yields a high sensitivity and specificity for coronary artery lesions in men but a lower sensitivity and specificity in women with aortic stenosis. (orig./MG)

Identification of the ENT1 antagonists dipyridamole and dilazep as amplifiers of oncolytic herpes simplex virus-1 replication.

Science.gov (United States)

Passer, Brent J; Cheema, Tooba; Zhou, Bingsen; Wakimoto, Hiroaki; Zaupa, Cecile; Razmjoo, Mani; Sarte, Jason; Wu, Shulin; Wu, Chin-lee; Noah, James W; Li, Qianjun; Buolamwini, John K; Yen, Yun; Rabkin, Samuel D; Martuza, Robert L

2010-05-15

Oncolytic herpes simplex virus-1 (oHSV) vectors selectively replicate in tumor cells, where they kill through oncolysis while sparing normal cells. One of the drawbacks of oHSV vectors is their limited replication and spread to neighboring cancer cells. Here, we report the outcome of a high-throughput chemical library screen to identify small-molecule compounds that augment the replication of oHSV G47Delta. Of the 2,640-screened bioactives, 6 compounds were identified and subsequently validated for enhanced G47Delta replication. Two of these compounds, dipyridamole and dilazep, interfered with nucleotide metabolism by potently and directly inhibiting the equilibrative nucleoside transporter-1 (ENT1). Replicative amplification promoted by dipyridamole and dilazep were dependent on HSV mutations in ICP6, the large subunit of ribonucleotide reductase. Our results indicate that ENT1 antagonists augment oHSV replication in tumor cells by increasing cellular ribonucleoside activity. (c)2010 AACR.

Bone regeneration in critical bone defects using three-dimensionally printed β-tricalcium phosphate/hydroxyapatite scaffolds is enhanced by coating scaffolds with either dipyridamole or BMP-2.

Science.gov (United States)

Ishack, Stephanie; Mediero, Aranzazu; Wilder, Tuere; Ricci, John L; Cronstein, Bruce N

2017-02-01

Bone defects resulting from trauma or infection need timely and effective treatments to restore damaged bone. Using specialized three-dimensional (3D) printing technology we have created custom 3D scaffolds of hydroxyapatite (HA)/beta-tri-calcium phosphate (β-TCP) to promote bone repair. To further enhance bone regeneration we have coated the scaffolds with dipyridamole, an agent that increases local adenosine levels by blocking cellular uptake of adenosine. Nearly 15% HA:85% β-TCP scaffolds were designed using Robocad software, fabricated using a 3D Robocasting system, and sintered at 1100°C for 4 h. Scaffolds were coated with BMP-2 (200 ng mL -1 ), dypiridamole 100 µM or saline and implanted in C57B6 and adenosine A2A receptor knockout (A2AKO) mice with 3 mm cranial critical bone defects for 2-8 weeks. Dipyridamole release from scaffold was assayed spectrophotometrically. MicroCT and histological analysis were performed. Micro-computed tomography (microCT) showed significant bone formation and remodeling in HA/β-TCP-dipyridamole and HA/β-TCP-BMP-2 scaffolds when compared to scaffolds immersed in vehicle at 2, 4, and 8 weeks (n = 5 per group; p ≤ 0.05, p ≤ 0.05, and p ≤ 0.01, respectively). Histological analysis showed increased bone formation and a trend toward increased remodeling in HA/β-TCP- dipyridamole and HA/β-TCP-BMP-2 scaffolds. Coating scaffolds with dipyridamole did not enhance bone regeneration in A2AKO mice. In conclusion, scaffolds printed with HA/β-TCP promote bone regeneration in critical bone defects and coating these scaffolds with agents that stimulate A2A receptors and growth factors can further enhance bone regeneration. These coated scaffolds may be very useful for treating critical bone defects due to trauma, infection or other causes. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 366-375, 2017. © 2015 Wiley Periodicals, Inc.

Diagnostic Value of Myocardial Perfusion SPECT with Dipyridamole in a Female Population

International Nuclear Information System (INIS)

Perez-Iruela, Juan; Pastor, Purificacion; Lumbreras, Luis; Martin, Ana M.; Ruiz, Francisco J.; Posadas, A.; Puentes, Carmen

2009-01-01

Background: Exercise stress scintigraphy is a safe procedure widely used for the diagnosis of ischemic heart disease. Pharmacologic stress testing is an important alternative. The delayed presentation of ischemic heart disease in women, together with a lower diagnostic accuracy of exercise stress testing in this population, has generated interest in the potential benefits provided by myocardial perfusion imaging tests. Objective: To determine the diagnostic value of myocardial perfusion images with 99m Tc-tetrofosmin in a one day protocol after a pharmacologic stress with dipyridamole in a female population, and the relation with the coronary territories using coronary angiography as a reference technique. Material and Methods: In total, 149 clinical charts of women with suspected ischemic heart disease undergoing myocardial perfusion imaging tests and coronary angiography were retrospectively analyzed. Results: Sensitivity and specificity were 94% (93.47%-94.53%) and 82% (80.94%-83.06%), respectively. Values of sensitivity and specificity according to coronary territories were 71.62% (70.88%-72.36%) and 76% (75.27%-76.73%) for the left anterior descending (LAD) artery, 69.09% (68.11%-70.07%) and 76.84% (76.26%-77.42%) for the left circumflex (LCx) coronary artery, and 87.23% (86.11%-88.36%) and 74.51% (73.97%-75.05%) for the right coronary artery (RCA), respectively. Conclusion: Myocardial perfusion scintigraphy with 99m Tc-tetrofosmin and dipyridamole using a one day stress-rest protocol has high sensitivity and specificity for the diagnosis of ischemic heart disease in women. (authors) [es

Prolonged Atrioventricular Block and Ventricular Standstill Following Adenosine Triphosphate Injection in a Patient Taking Dipyridamole and Antiarrhythmic Agents: A Case Report

Directory of Open Access Journals (Sweden)

Kotaro Oe, MD

2009-01-01

Full Text Available An 83-year-old woman was admitted to our hospital because of palpitation. She had hypertension and paroxysmal atrial fibrillation, treated with digoxin and cibenzoline, and took dipyridamole for microalbuminuria. Before admission, she had taken pilsicainide pills in addition. On admission, electrocardiogram showed regular tachycardia with mildly prolonged QRS width. For the purpose of terminating tachycardia, 10 mg of adenosine triphosphate (ATP was rapidly injected. About 20 sec later, atrioventricular block and ventricular standstill occurred. She presented loss of consciousness and convulsion, and chest compression was performed. About 30 sec later, the QRS complex reappeared, and she became alert. Serum concentration of digoxin, cibenzoline and pilsicainide was within therapeutic level, respectively. We should be cautious in using ATP for a patient taking dipyridamole and antiarrhythmic agents.

Prevention of one-year vein-graft occlusion after aortocoronary-bypass surgery: a comparison of low-dose aspirin, low-dose aspirin plus dipyridamole, and oral anticoagulants. The CABADAS Research Group of the Interuniversity Cardiology Institute of The Netherlands

NARCIS (Netherlands)

van der Meer, J.; Hillege, H. L.; Kootstra, G. J.; Ascoop, C. A.; Mulder, B. J.; Pfisterer, M.; van Gilst, W. H.; Lie, K. I.

1993-01-01

Aspirin, alone or in combination with dipyridamole, is known to prevent occlusion of aortocoronary vein grafts. The benefit of dipyridamole in addition to aspirin remains controversial, and the efficacy and safety of oral anticoagulants for prevention of vein-graft occlusion have not been

Dipyridamole thallium imaging for detecting cardiac involvement in patients with systemic sclerosis (scleroderma)

Energy Technology Data Exchange (ETDEWEB)

Ishida, Yoshio; Matsubara, Noboru; Tani, Akihiro; Morozumi, Takakazu; Hori, Masatsugu; Kitabatake, Akira; Kamada, Takenobu; Kimura, Kazufumi; Kozuka, Takahiro (Osaka Univ. (Japan). Faculty of Medicine)

1990-02-01

Dipyridamole thallium-201 imaging was carried out in 21 patients with progressive systemic sclerosis (PSS) to assess its value in detecting impaired myocardium and coronary microcirculation associated with PSS. Depending upon the degree of cardiac function, the patients were classified as having either ejection fraction of 50% or more (Group I, n=17) or less than 50% (Group II, n=4). In Group I, four patients had transient defect in which perfusion defects were seen on early images but not seen on delayed images; three had reverse redistribution in which defects were not seen on early images but seen on delayed images; and three had persistent defects which were seen on both early and delayed images. A decreased washout of thallium-201 was seen in 9 patients. In an analysis of both perfusion defects and washout rate, 13 patients (76%) in Group I were found to have abnormal findings. This suggests that disturbed coronary microcirculation or impaired myocardium may frequently develop even when EF is normal. All of the patients categorized as having a decreased cardiac function (Group II) had perfusion defect, suggesting the presence of myocardial fibrosis. In PSS, deterioration of cardiac function seemed to be associated with progression of myocardial fibrosis. Dipyridamole thallium imaging may be a sensitive method for detecting cardiac lesions in PSS. It also has the potential for detecting decreased coronary flow reserve or slightly impaired myocardium even without decreased EF. (N.K.).

Prognostic value of intravenous dipyridamole thallium scintigraphy after an acute myocardial ischemic event

International Nuclear Information System (INIS)

Younis, L.T.; Byers, S.; Shaw, L.; Barth, G.; Goodgold, H.; Chaitman, B.R.

1989-01-01

Seventy-seven patients recovering from an acute coronary event were studied by intravenous dipyridamole thallium scintigraphy to evaluate the prognostic value and safety of the test in this patient subset. Forty-four patients (58%) had unstable angina and 33 (42%) had an acute myocardial infarction. One death occurred within 24 hours of testing. Sixty-eight patients were followed for an average of 12 months; 25, 31 and 23% had a fixed, reversible or combined thallium defect on their predischarge thallium scan. During follow-up, 10 patients died or had a nonfatal myocardial infarction; in each case, a reversible or combined myocardial thallium defect was present. Univariate analysis of 17 clinical, scintigraphic and angiographic variables showed that a reversible thallium defect and the angiographically determined extent of coronary artery disease were predictors of future cardiac events. The extent of coronary disease and global left ventricular ejection fraction were predictors of subsequent reinfarction or death. Logistic regression analyses revealed that a reversible thallium defect (p less than 0.001) and the extent of coronary disease (p less than 0.009) were the only significant predictors of a cardiac event. When death or reinfarction were the outcome variables, the extent of coronary disease (p less than 0.02) and left ventricular ejection fraction (p less than 0.06) were the only variables selected. Thus, intravenous dipyridamole thallium scintigraphy after an acute coronary ischemic syndrome is a useful and relatively safe noninvasive test to predict subsequent cardiac events

Aspirin plus dipyridamole has the highest surface under the cumulative ranking curves (SUCRA) values in terms of mortality, intracranial hemorrhage, and adverse event rate among 7 drug therapies in the treatment of cerebral infarction.

Science.gov (United States)

Zhang, Jian-Jun; Liu, Xin

2018-03-01

The standardization for the clinical use of drug therapy for cerebral infarction (CI) has not yet determined in some aspects. In this paper, we discussed the efficacies of different drug therapies (aspirin, aspirin plus dipyridamole, aspirin plus clopidogrel, aspirin plus warfarin, cilostazol, warfarin, and ticlopidine) for CI. We searched databases of PubMed and Cochrane Library from the inception to April, 2017, randomized controlled trials (RCTs) met the inclusion and exclusion criteria were enrolled in this study. The network meta-analysis integrated evidences of direct and indirect comparisons to assess odd ratios (OR) and surface under the cumulative ranking curves (SUCRA) value. Thirteen eligible RCTs including 7 drug therapies were included into this network meta-analysis. The network meta-analysis results showed that CI patients who received aspirin plus dipyridamole presented lower mortality when compared with those received aspirin plus clopidogrel (OR = 0.46, 95% CI = 0.18-0.99), indicating aspirin plus dipyridamole therapy had better efficacy for CI. As for intracranial hemorrhage (ICH), stroke recurrence, and adverse event (AE) rate, there were no significant differences of efficacy among 7 drug therapies. Besides, SUCRA values demonstrated that in the 7 drug therapies, aspirin plus dipyridamole therapy was more effective than others (mortality: 80.67%; ICH: 76.6%; AE rate: 90.2%). Our findings revealed that aspirin plus dipyridamole therapy might be the optimum one for patients with CI, which could help to improve the survival of CI patients.

Biphasic 201thallium scintgraphy after dipyridamole in mitral valve diseases

International Nuclear Information System (INIS)

Schmoliner, R.; Dudczak, R.; Kronik, G.; Moesslacher, H.; Kletter, K.; Frischauf, H.

1980-01-01

The results of biphasic 201 thallium scintigraphy after dipyridamole i.v. could neither prove nor exclude the presence of small focal lesions in the myocardium of 17 patients with mitral valve diseases. The frequent finding of a decrease in activity in the anterolateral myocardium is probably due to a relative increase in activity in the region of the inferior wall with superimposed areas of the papillary muscle and right ventricular myocardium. If the right ventricle is visualized in stress- or redistribution images, an increase in mean pulmonary artery pressure can be accepted. According to Cohen's criteria, a grade 2 or 3 virtually proves the existence of pulmonary hypertension, a grade 1 makes this finding rather probable. The possibility of pulmonary hypertension can not be excluded if the right ventricular myocardium is not visualized. (orig.) [de

Analytical Method Development and Validation for the Quantification of Acetone and Isopropyl Alcohol in the Tartaric Acid Base Pellets of Dipyridamole Modified Release Capsules by Using Headspace Gas Chromatographic Technique

Directory of Open Access Journals (Sweden)

Sriram Valavala

2018-01-01

Full Text Available A simple, sensitive, accurate, robust headspace gas chromatographic method was developed for the quantitative determination of acetone and isopropyl alcohol in tartaric acid-based pellets of dipyridamole modified release capsules. The residual solvents acetone and isopropyl alcohol were used in the manufacturing process of the tartaric acid-based pellets of dipyridamole modified release capsules by considering the solubility of the dipyridamole and excipients in the different manufacturing stages. The method was developed and optimized by using fused silica DB-624 (30 m × 0.32 mm × 1.8 µm column with the flame ionization detector. The method validation was carried out with regard to the guidelines for validation of analytical procedures Q2 demanded by the International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use (ICH. All the validation characteristics were meeting the acceptance criteria. Hence, the developed and validated method can be applied for the intended routine analysis.

Myocardial perfusion assessment at rest and after dipyridamole: MR signal intensity characteristics of reversible and persistent hypoperfusion

International Nuclear Information System (INIS)

Wintersperger, B.J.; Penzkofer, H.V.; Huber, A.; Meininger, M.; Scheidler, J.; Reiser, M.; Knez, A.; Haberl, R.; Kerner, M.; Knesewitsch, P.

2000-01-01

Methods: Sixteen patients with CAD underwent MR myocardial perfusion assessment at rest and after dipyridamole-induced hyperemia. Qualitative parameters (SI increase, SI upslope) of the SI time-curves were evaluated and characteristics of normal, reversible and persistent hypoperfused myocardium as assessed by 99m TC-SestaMIBI SPECT were compared. Results: Compared with the rest values, normal myocardium showed a significant increase of the SI upslope during hyperemia (P [de

Is dipyridamole test equivalent to exercise testing for the performing of myocardial tomo-scintigraphy? preliminary results of a systematic comparative analysis in patients having documented episodes of myocardial ischemia

International Nuclear Information System (INIS)

David, N.; Quiri, N.; Hassan, N.; Arsena, T.; Py, M.; Olivier, P.; Karcher, G.; Bertrand, A.; Houriez, P.; Grentzinger, A.; Angioi, M.; Danchin, N.; Juilliere, Y.

1997-01-01

Dipyridamole test is generally used rather than exercise testing when myocardial tomo-scintigraphy (MTS) is performed with patients unable to perform a maximal exercise test. However, this choice has never been validated by a systematic comparative analysis of the results provided by these two stress techniques with patients having a documented myocardial ischemia. We have included 20 patients who had a known coronary artery disease, for whom exercise test was positive at the time of an exercise MTS-TI201 performed in our department and who underwent an additional MTS-TI201 after intravenous administration of 0,56 mg/kg of dipyridamole and low-level exercise testing (40 W). The extent of perfusion abnormalities, observed after dipyvirdamole, was not significantly different from that evidenced at exercise, even in the analysis restricted to the eight patients who had a sub-maximal test (<80 % of predicted maximal heart rate) at the time of exercise-MTS (% of left ventricle: 17 ± 13 vs 15 ± 8). By contrast, there were important individual variations: a difference in defect-extent (≥ 10 % of left ventricle) was observed between the two tests for 11 patients (55 %), the largest defect being that observed at exercise in six cases, and after dipyridamole in five cases. With patients having exercise myocardial ischemia, the MTS obtained after dipyridamole are frequently very different from those performed after exercise, and the criterion of a low maximal heart rate doses not imply an underestimation of the perfusion abnormalities observed at exercise. (authors)

The usefulness of dipyridamole thallium-201 single photon emission computed tomography for predicting perioperative cardiac events in patients undergoing non-cardiac vascular surgery

International Nuclear Information System (INIS)

Chen, Tao; Kuwabara, Yasuo; Tsutsui, Hiroyuki; Sasaki, Masayuki; Nakagawa, Makoto; Koga, Hirofumi; Kaneko, Kouichirou; Komori, Kimihiro; Masuda, Kouji

2002-01-01

The aim of this study was to evaluate the usefulness of dipyridamole Tl-201 myocardium single photon emission computed tomography ( 201 Tl-SPECT) for predicting perioperative cardiac events in patients with arteriosclerosis obliterans (ASO) and abdominal aortic aneurysm (AAA) undergoing non-cardiac vascular surgery. Preoperative dipyridamole 201 Tl-SPECT imaging in association with clinical risk assessment was performed in 224 consecutive patients (97 ASO and 127 AAA). The patients were classified into three groups, including low-risk (n=173, 77%), intermediate-risk (n=39, 18%), and high-risk (n=12, 5%) groups according to the clinical risk stratification. The prevalence of reversible Tl-201 defect was significantly higher in the high-risk group than that in the low-risk group (83% vs. 14%, p 201 Tl-SPECT was the only variable to predict perioperative cardiac events by a stepwise logistic regression analysis (odds ratio 7.0, 95% confidence interval 1.7-28.0, p=0.007). It was also a significant predictor of perioperative cardiac events in a subgroup of low risk patients (odds ratio 11.6, 95% confidence interval 2.3-57.4, p=0.004). The sensitivity and specificity of the reversible defect for predicting perioperative cardiac events were 55.6% and 84.8% in all operated patients, and 57.1% and 89.7% in low risk patients, respectively. The preoperative dipyridamole 201 Tl-SPECT was useful for predicting perioperative cardiac events in patients with vascular diseases, even in patients identified as having a low risk based on the clinical risk assessment. (author)

Prognostic utility of intravenous dipyridamole thallium-201 imaging and exercise testing after an acute infarction

International Nuclear Information System (INIS)

Leppo, J.A.

1984-01-01

To define the prognosis in asymptomatic survivors of acute infarcts (MI), coronary vasodilation was induced with I.V. dipyridamole, followed by Thallium-201 (T1) imaging in 26 patients just prior to discharge. All patients (pts) also had a modified exercise treadmill (MET) test. During the imaging protocol, 10 (39%) pts experienced transient adverse effects and 12 (46%) pts had either angina or ST depression with MET. During a mean follow-up of 17 months, 13 (50%) pts had a cardiac event defined as readmission for control of angina, MI or death. In the 13 pts having cardiac events, 4 (31%) had ST depression and 2 (15%) had angina during MET, but 12 (92%) demonstrated T1 redistribution (RD) as determined by at least 1 segment/scan having a transient defect. A logistic regression analysis using several exercise, scintigraphic and general clinical parameters, showed that the presence of T1 RD was the only significant (p <0.001) predictor for future cardiac events. The predicted probability for events in pts with T1 RD was 80 +- 10% (SD) and was 9 +- 9% in those without T1 RD. The mean number of defects per scan was similar in pts with and without cardiac events, but compared to persistent defects, transient ones are associated with potentially ischemic myocardium. Although the pt population is relatively small, dipyridamole T1 imaging after MI appears to be safe and has demonstrated prognostic value. It also offers an alternative and/or addition to exercise testing in the predischarge evaluation after acute MI

Effect of various antithrombotic regimens (aspirin, aspirin plus dipyridamole, anticoagulants) on the functional status of patients and grafts one year after coronary artery bypass grafting

NARCIS (Netherlands)

Mulder, B. J.; van der Doef, R. M.; van der Wall, E. E.; Tijssen, J. G.; Piek, J. J.; van der Meer, J.; Dunning, A. J.

1994-01-01

From 1987 until 1991 a large prospective randomized multicentre study was performed in The Netherlands, Germany and Switzerland entitled CABADAS (Prevention of Coronary Artery Bypass graft occlusion by Aspirin, Dipyridamole, and Acenocoumarol/Phenprocoumon Study). The aim of CABADAS was to evaluate

Effects of low dose aspirin (50 mg/day), low dose aspirin plus dipyridamole, and oral anticoagulant agents after internal mammary artery bypass grafting: patency and clinical outcome at 1 year. CABADAS Research Group of the Interuniversity Cardiology Institute of The Netherlands. Prevention of Coronary Artery Bypass Graft Occlusion by Aspirin, Dipyridamole and Acenocoumarol/Phenprocoumon Study

NARCIS (Netherlands)

van der Meer, J.; Brutel de la Rivière, A.; van Gilst, W. H.; Hillege, H. L.; Pfisterer, M.; Kootstra, G. J.; Dunselman, P. H.; Mulder, B. J.; Lie, K. I.

1994-01-01

This study was performed to compare the efficacy and safety of aspirin, aspirin plus dipyridamole, and oral anticoagulant agents in the prevention of internal mammary artery graft occlusion. Antithrombotic drugs increase vein graft patency after coronary artery bypass surgery. Their benefit after

The significance of a dipyridamole induced [sup 99m]Tc-MIBI perfusion abnormality on single photon emission tomography: A quantiative validation with labelled water and positron emission tomography

Energy Technology Data Exchange (ETDEWEB)

Rechavia, E.; Galassi, A.R.; Araujo, L.I.; Halson, P.; Lammertsma, A.; Jones, T.; Lavender, J.P.; Maseri, A. (Royal Postgraduate Medical School, London (United Kingdom). Nuclear Medicine Dept. Medical Research Council, London (United Kingdom). Cyclotron Unit Medical Research Council, London (United Kingdom). Cardiovascular Unit)

1992-12-01

To relate [sup 99m]Tc-MIBI uptake to regional myocardial blood flow (rMBF), [sup 99m]Tc-MIBI SPET and H[sub 2] [sup 15]O PET scans were obtained at rest and after dipyridamole infusion in six patients with single vessel coronary artery disease. [sup 99m]Tc-MIBI-H[sub 2] [sup 15]O data sets were created for each segment perfused by the stenotic vessel and for a normal reference area, assigning regions on the SPET tomograms to comparable regions on the PET by similar transaxial image reconstructions. All patients demonstrated post-dipyridamole [sup 99m]Tc-MIBI perfusion defects in the territories supplied by the stenotic arteries; Resting rMBF in these regions was slightly lower than that in the normal areas. A 43% [+-] 14% reduction in [sup 99m]Tc-MIBI activity in the area at risk was coupled with on average a 60% [+-] 9% reduction in post-dipyridamole rMBF compared with control regions. Thus, SPET assessment of [sup 99m]Tc-MIBI uptake tends to underestimate the perfusion contrast between areas with normal and areas with low coronary vasodilatory reserve when compared to PET. However, these findings may still not affect the clinical usefulness of [sup 99m]Tc-MIBI and more extensive studies are required to confirm these results in the clinical environment (orig./MG).

Dipyridamole plus aspirin versus aspirin alone in the secondary prevention after TIA or stroke: a meta-analysis by risk

OpenAIRE

Halkes, P.H.A.; Gray, Laura J.; Bath, Philip M.W.; Diener, Hans-Christoph; Guiraud-Chaumeil, B.

2008-01-01

Objectives: Our aim was to study the effect of combination therapy with aspirin and dipyridamole (A+D) over aspirin alone (ASA) in secondary prevention after transient \\ud ischemic attack or minor stroke of presumed arterial origin and to perform subgroup analyses to identify patients that might benefit most from secondary prevention with A+D.\\ud Data sources: The previously published meta-analysis of individual patient data was updated with data from ESPRIT (N=2,739); trials without data on ...

Prognostic importance of silent myocardial ischemia detected by intravenous dipyridamole thallium myocardial imaging in asymptomatic patients with coronary artery disease

International Nuclear Information System (INIS)

Younis, L.T.; Byers, S.; Shaw, L.; Barth, G.; Goodgold, H.; Chaitman, B.R.

1989-01-01

One hundred seven asymptomatic patients who underwent intravenous dipyridamole thallium imaging were evaluated to determine prognostic indicators of subsequent cardiac events over an average follow-up period of 14 +/- 10 months. Univariate analysis of 18 clinical, scintigraphic and angiographic variables revealed that a reversible thallium defect, a combined fixed and reversible thallium defect, number of segmental thallium defects and extent of coronary artery disease were significant predictors of subsequent cardiac events. Of the 13 patients who died or had a nonfatal infarction, 12 had a reversible thallium defect. Stepwise logistic regression analysis selected a reversible thallium defect as the only significant predictor of cardiac events. When death or myocardial infarction was the outcome variable, a combined fixed and reversible thallium defect was the only predictor of outcome. In patients without previous myocardial infarction, the cardiac event rate was significantly greater in those with an abnormal versus normal thallium scan (55% versus 12%, p less than 0.001). Thus, intravenous dipyridamole thallium scintigraphy is a useful noninvasive test to risk stratify asymptomatic patients with coronary artery disease. A reversible thallium defect most likely indicates silent myocardial ischemia in a sizable fraction of patients in this clinical subset and is associated with an unfavorable prognosis

Dipyridamole thallium imaging may not be a reliable screening test for coronary artery disease in patients undergoing vascular surgery

International Nuclear Information System (INIS)

Marwick, T.H.; Underwood, D.A.

1990-01-01

Dipyridamole thallium imaging has been proposed for cardiac risk stratification in patients undergoing peripheral vascular surgery. The purpose of this study was to define the benefit of this investigation in routine preoperative evaluation of these patients. The outcome of 86 patients undergoing vascular surgery procedures was examined in light of preoperative clinical assessment and dipyridamole SPECT thallium imaging (DST). Fifty-one patients (59%) were considered at high risk on clinical grounds, and 22 patients (26%) had perfusion defects. Ten patients suffered a perioperative coronary event, including unstable angina, myocardial infarction, or cardiac death. Seven of the patients with such events were among the 51 clinically high-risk subjects (14%). Three perioperative events occurred in the group of 19 patients with positive DST images who underwent surgery (16%), but the DST test failed to identify 7 patients who suffered coronary events. The frequency of abnormal thallium imaging was similar to the prevalence of angiographically significant coronary disease reported previously at this center, but considerably less than the rate of abnormal thallium imaging in past studies of vascular surgery patients. The application of the test to a low to moderate risk population is probably responsible for its lower predictive accuracy for coronary events. DST is not an ideal routine noninvasive technique for risk stratification in patients undergoing vascular surgery

Reverse redistribution in dipyridamole-loading thallium-201 images using single photon emission computed tomography

International Nuclear Information System (INIS)

Mori, Kiyoo; Masuda, Masanosuke; Bunko, Hisashi.

1986-01-01

Dipyridamole was infused intravenously at a rate of 0.142 mg/kg per min for four min, and a stress image was obtained 10 min after the injection of two mCi 201 Tl. The myocardial image of Tl was analyzed by single photon emission computed tomography and its washout rate was calculated by the segmental ROI method. Myocardial function and the motion of the left ventricular wall were analyzed by 99m Tc-RBC-gated cardiac pool imaging. Reverse redistribution was noted in 27 (21.6 %) of 125 consecutive Tl dipyridamole and redistribution myocardial imaging studies. The stress image demonstrated normal perfusion (group 1) and reduced perfusion (group 2) of Tl. Group 1 consisted of 17 patients with diabetes mellitus, supraventricular arrhythmias, hypertension, and others. Group 2 consisted of 10 patients with subendocardial infarction, diabetes mellitus, and hypertension, and others. The percentage prevalence of reverse redistribution among patients with supraventricular arrhythmia was 62.5 % (five of eight patients), with subendocardial infarction 60.0 % (three of five), with hypertension 42.8 % (six of 14), and with diabetes mellitus 40.0 % (eight of 20), while in those with transmyocardial infarction and angina pectoris no reverse redistribution percentage was found. The washout rate of Tl in normal perfusion areas was 44.0 ± 12.8 %, the reverse redistribution of group 1 was 47.4 ± 12.8 %, and of group 2 was 51.2 ± 8.2 %. The washout rate of the reverse redistribution of group 2 was significantly greater than that of the normal areas. In gated cardiac pool imaging, patients in group 2 had significantly larger areas showing abnormal contraction of the left ventricular wall and significantly lower ejection fraction than did group 1. In the electrocardiogram ST segment depression was noted more frequently in group 2 than group 1. No Q wave was present in the corresponding reverse redistribution area. (J.P.N.)

The clinical impact of perfusion scintigraphy with dipyridamole

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Schechtmann, N.; Dae, M.; Lanzer, P.; Sajardo, L.; Faulkner, D.; Botvinick, E.

1984-01-01

In order to assess their clinical impact, the authors analyzed perfusion scintigrams (PS) with dipyridamole (D) and the resultant clinical management in 41 consecutive patients (PTS). Population mean age was 67, with 22 males and represented 14% of those having PS. Fifteen PTS had rest chest pain of unknown cause and 26 PTS had pain typical or suggestive of angina but couldn't undergo dynamic stress due to claudication, arthritis, amputation, stroke, recent surgery or other disability. Four PTS were studies for surgical clearance, 3 following angiography to assess coronary pathophysiology and 9 had prior negative or equivocal stress PS at suboptimal levels. Among 18 PTS with reversible scintigraphic abnormalities, 10 underwent subsequent catheterization, with successful CABG in 7, PTCA in 1, aggressive medical treatment of ischemia in 11, and 2 had noncoronary surgery delayed. One PT with associated extensive fixed abnormalities underwent CABG and died late in heart failure. Among 23 PTS without significant scintigraphic reversibility, 8 with normal studies were discharged, 3 went on to uncomplicated noncardiac surgery and 11 PTS, 9 with dilated cardiomyopathy, were managed without therapeutic change. D infusion was uncomplicated and related findings on PS correlated well with coronary angiography, where available in 19 of 20 PTS. PS with D: 1) is safe; 2) correlates closely with coronary anatomy; and 3) adds unique, important pathophysiologic information to clinical evaluation and impacts strongly on the management of a large number of PTS with known or suspected coronary disease

The usefulness of dipyridamole thallium-201 single photon emission computed tomography for predicting perioperative cardiac events in patients undergoing non-cardiac vascular surgery

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Chen Tao; Huang Gang

2004-01-01

The aim of this study was to evaluate the usefulness of dipyridamole Tl-201 myocardium single photon emission computed tomography (201Tl-SPECT) for predicting perioperative cardiac events in patients with arteriosclerosis obliterans (ASO) and abdominal aortic aneurysm (AAA) undergoing non-cardiac vascular surgery. Methods: Preoperative dipyridamole 201Tl-SPECT imaging in association with clinical risk assessment was performed in 224 consecutive patients (97 ASO and 127 AAA). Results: The patients were classified into three groups, including low-risk (n=173, 77%), intermediate-risk (n=39, 18%), and high-risk (n=12, 5%) groups according to the clinical risk stratification. The prevalence of reversible Tl-201 defect was significantly higher in the high-risk group than that in the low-risk group (83% vs. 14%, p<0.001). In 180 patients who underwent vascular surgery, 9 patients (5.0%) had perioperative cardiac events, including heart failure (n=l), unstable angina (n=2), and other cardiac events such as arrhythmias (n=6). The clinical variables including the clinical risk stratification did not significantly correlate with the perioperative cardiac events. In contrast, the reversible defect on 201Tl-SPECT was the only variable to predict perioperative cardiac events by a stepwise logistic regression analysis (odds ratio 7.0, 95% confidence interval l.7-28.0, p=0.007). It was also a significant predictor of perioperative cardiac events in a subgroup of low risk patients (odds ratio 11.6, 95% confidence interval 2.3-57.4, p=0.004). The sensitivity and specificity of the reversible defect for predicting perioperative cardiac events were 55.6% and 84.8% in all operated patients, and 57.1% and 89.7% in low risk patients, respectively. Conclusions: The preoperative dipyridamole 201Tl-SPECT was useful for predicting perioperative cardiac events in patients with vascular diseases, even in patients identified as having a low risk based on the clinical risk assessment. (authors)

The impact of supersaturation level for oral absorption of BCS class IIb drugs, dipyridamole and ketoconazole, using in vivo predictive dissolution system: Gastrointestinal Simulator (GIS).

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Tsume, Yasuhiro; Matsui, Kazuki; Searls, Amanda L; Takeuchi, Susumu; Amidon, Gregory E; Sun, Duxin; Amidon, Gordon L

2017-05-01

The development of formulations and the assessment of oral drug absorption for Biopharmaceutical Classification System (BCS) class IIb drugs is often a difficult issue due to the potential for supersaturation and precipitation in the gastrointestinal (GI) tract. The physiological environment in the GI tract largely influences in vivo drug dissolution rates of those drugs. Thus, those physiological factors should be incorporated into the in vitro system to better assess in vivo performance of BCS class IIb drugs. In order to predict oral bioperformance, an in vitro dissolution system with multiple compartments incorporating physiologically relevant factors would be expected to more accurately predict in vivo phenomena than a one-compartment dissolution system like USP Apparatus 2 because, for example, the pH change occurring in the human GI tract can be better replicated in a multi-compartmental platform. The Gastrointestinal Simulator (GIS) consists of three compartments, the gastric, duodenal and jejunal chambers, and is a practical in vitro dissolution apparatus to predict in vivo dissolution for oral dosage forms. This system can demonstrate supersaturation and precipitation and, therefore, has the potential to predict in vivo bioperformance of oral dosage forms where this phenomenon may occur. In this report, in vitro studies were performed with dipyridamole and ketoconazole to evaluate the precipitation rates and the relationship between the supersaturation levels and oral absorption of BCS class II weak base drugs. To evaluate the impact of observed supersaturation levels on oral absorption, a study utilizing the GIS in combination with mouse intestinal infusion was conducted. Supersaturation levels observed in the GIS enhanced dipyridamole and ketoconazole absorption in mouse, and a good correlation between their supersaturation levels and their concentration in plasma was observed. The GIS, therefore, appears to represent in vivo dissolution phenomena and

Serum caffeine levels after 24 hours of caffeine abstention: observations on clinical patients undergoing myocardial perfusion imaging with dipyridamole or adenosine

International Nuclear Information System (INIS)

Jacobson, A.F.; Cerqueira, M.D.; Raisys, V.; Shattuc, S.

1994-01-01

Although caffeine attenuates the vasodilatation produced by dipyridamole and adenosine, and is therefore contraindicated when these agents are used for myocardial perfusion scintigraphy, caffeine levels in clinical patients undergoing standard imaging protocols have not been studied. Eighty-six patients undergoing clinically indicated intravenous dipyridamole (n=75) or adenosine (n=11) thallium-201 myocardial perfusion scintigraphy, all of whom reported abstention from products containing caffeine for 24 h, were studied prospectively. Blood samples were drawn prior to initiation of the pharmacologic infusion, and serum caffeine levels were determined using an enzyme immunoassay technique. Results of these determinations were correlated with maximum pulse and blood pressure changes measured during and immediately after the stressor infusion, and thallium imaging findings. Detectable caffeine levels were found in 34 patients (40%), ranging from 0.1 to 5.0 mg/l. There was no significant difference in mean systolic blood pressure decrease or mean pulse increase between patients with caffeine levels > 1.0 mg/l (20.4 ± 18.2 mmHg, 11.0 ± 8.9 BPM; n=5) and those with lower (0.1 to 0.9 mg/l) (15.4 ± 9.5 mmHg, 14.4 ± 8.2 BPM; n=29) or no detectable caffeine levels (18.0 ± 11.5 mmHg, 16.6 ± 10.1 BPM; n=52). Redistribution on thallium imaging was also identified with a similar frequency in these three groups (2/5, 40%; 8/29, 28%; 22/52, 42% respectively). (orig.)

Serum caffeine levels after 24 hours of caffeine abstention: observations on clinical patients undergoing myocardial perfusion imaging with dipyridamole or adenosine

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Jacobson, A.F. (Nuclear Medicine Section, Dept. of Veterans Affairs Medical Center, Seattle, WA (United States) Univ. of Washington, Seattle, WA (United States)); Cerqueira, M.D. (Nuclear Medicine Section, Dept. of Veterans Affairs Medical Center, Seattle, WA (United States) Univ. of Washington, Seattle, WA (United States)); Raisys, V. (Dept. of Lab. Medicine, Harborview Medical Center, Seattle, WA (United States) Univ. of Washington, Seattle, WA (United States)); Shattuc, S. (Univ. of Washington, Seattle, WA (United States))

1994-01-01

Although caffeine attenuates the vasodilatation produced by dipyridamole and adenosine, and is therefore contraindicated when these agents are used for myocardial perfusion scintigraphy, caffeine levels in clinical patients undergoing standard imaging protocols have not been studied. Eighty-six patients undergoing clinically indicated intravenous dipyridamole (n=75) or adenosine (n=11) thallium-201 myocardial perfusion scintigraphy, all of whom reported abstention from products containing caffeine for 24 h, were studied prospectively. Blood samples were drawn prior to initiation of the pharmacologic infusion, and serum caffeine levels were determined using an enzyme immunoassay technique. Results of these determinations were correlated with maximum pulse and blood pressure changes measured during and immediately after the stressor infusion, and thallium imaging findings. Detectable caffeine levels were found in 34 patients (40%), ranging from 0.1 to 5.0 mg/l. There was no significant difference in mean systolic blood pressure decrease or mean pulse increase between patients with caffeine levels > 1.0 mg/l (20.4 [+-] 18.2 mmHg, 11.0 [+-] 8.9 BPM; n=5) and those with lower (0.1 to 0.9 mg/l) (15.4 [+-] 9.5 mmHg, 14.4 [+-] 8.2 BPM; n=29) or no detectable caffeine levels (18.0 [+-] 11.5 mmHg, 16.6 [+-] 10.1 BPM; n=52). Redistribution on thallium imaging was also identified with a similar frequency in these three groups (2/5, 40%; 8/29, 28%; 22/52, 42% respectively). (orig.)

201Tl in myocardial diagnosis: studies on the influence of dipyridamole, dobutamine ergometer exercise and background subtraction on the 201Tl myocadial scintiscam

International Nuclear Information System (INIS)

Seiderer, M.

1979-01-01

Changes in 201 Tl myocardial scintiscans upon administration of dipyridamole or dobutamine and upon ergometer exercise relative to scintiscans at rest were investigated as well as the influence of myocardial background subtraction on scintiscan quality and information. A total of 90 201 Tl examinations were carried out in 59 patients. 18 patients had no myocardial disease, 30 patients had a coronary disease, 5 patients suffered from cardiomyopathy and 6 from left ventricular hypertrophy. The findings are discussed in detail. (orig.) [de

Contrast agents provide a faster learning curve in dipyridamole stress echocardiography.

Science.gov (United States)

Zamorano, Jose; Sánchez, Violeta; Moreno, Raúl; Almería, Carlos; Rodrigo, Jose; Serra, Viviana; Azcona, Luis; Aubele, Adalia; Mataix, Luis; Sánchez-Harguindey, Luis

2002-12-01

Interobserver variability is an important limitation of the stress echocardiography and depends on the echocardiographer training. Our aim was to evaluate if the use of contrast agents during dipyridamole stress echocardiography would improve the agreement between an experienced and a non-experienced observer in stress echo and therefore if contrast would affect the learning period of dypyridamole stress echo. Two independent observers without knowledge of any patient data interpreted all stress studies. One observer was an experienced one and the other had experience in echocardiography but not in stress echo. Two observers analysed 87 non-selected and consecutive studies. Out of the 87 studies, 46 were performed without contrast administration, whereas i.v. contrast (2.5 g Levovist by two bolus at rest and at peak stress) was administered in 41. In all cases, second harmonic imaging and stress digitalisation pack was used. The agreement between observers showed a kappa index of 0.58 and 0.83 without and with contrast administration, respectively. The use of contrast agents provides a better agreement in the evaluation of stress echo between an experienced and a non-experienced observer in stress echo. Adding routinely contrast agents could probably reduce the number of exams required for the necessary learning curve in stress echocardiography.

Comparison of Diagnostic Accuracy for Detecting coronary Artery Disease of Dipyridamole 99mTc-MIBI Myocardial SPECT and It's Defect Map between Men and Women

International Nuclear Information System (INIS)

Lee, Dong Soo; Oh, Byung Hee; Chung, June Key; Lee, Myoung Mook; Park, Young Bae; Lee, Myung Chul; Seo, Jung Don; Lee, Young Woo; Koh, Chang Soon

1993-01-01

To evaluate the usefulness and differences in diagnosing coronary artery disease (CAD) between men and women of intravenous dipyridamole 99m Tc-MIBI myocardial SPECT, we obtained 99m Tc-MIBI myocardial SPECT and compared with the findings of coronary angiographies. Ninety eight male and 37 female patients who underwent dipyridamole 99m Tc- MIBI myocardial imaging within one month of cardiac catheterization were studied. Scans were considered abnormal if perfusion defect was detected and the defect size was more than 12% for left anterior descending artery (LAD) and circumflex(LCX) and 8% for right coronary artery (RCA) territories. Lesions ≥ 50% luminal diameter narrowing were considered significant CAD. Overall sensitivity for detection of CAD was 94.3% in men and 96.4% in women; specificity was 70% in men and 52.6% in women (P=not significant, ns). Vessel-matched sensitivity was 75.3% in men and 72.7% in women (P=ns); specificity was 84.6% in men and 67.9% in women (P 99m Tc-MIBI myocardial SPECT is a safe, noninvasive test for evaluation of CAD. There was no gender difference to detect CAD, but more false-positive rate in women especially in the territory of LAD.

Comparison of the myocardial blood flow response to regadenoson and dipyridamole: a quantitative analysis in patients referred for clinical 82Rb myocardial perfusion PET

International Nuclear Information System (INIS)

Goudarzi, Behnaz; Fukushima, Kenji; Bravo, Paco; Merrill, Jennifer; Bengel, Frank M.

2011-01-01

Regadenoson is a novel selective A 2A adenosine receptor agonist, which is administered as an intravenous bolus at a fixed dose. It is currently not clear if the absolute flow increase in response to this fixed dose is a function of distribution volume in individual patients or if it is generally comparable to the previous standard agents dipyridamole or adenosine, which are dosed based on weight. We used quantitative analysis of clinical 82 Rb PET/CT studies to obtain further insights. A total of 104 subjects with normal clinical rest/stress 82 Rb perfusion PET/CT were included in a retrospective analysis. To rule out confounding factors, none had evidence of prior cardiac disease, ischaemia or infarction, cardiomyopathy, diabetes with insulin use, calcium score >400, renal disease or other significant systemic disease. A group of 52 patients stressed with regadenoson were compared with a group of 52 patients stressed with dipyridamole before regadenoson became available. The groups were matched for clinical characteristics, risk factors and baseline haemodynamics. Myocardial blood flow (MBF) and myocardial flow reserve (MFR) were quantified using a previously validated retention model, after resampling of dynamic studies from list-mode 82 Rb datasets. At rest, heart rate, blood pressure and MBF were comparable between the groups. Regadenoson resulted in a significantly higher heart rate (34 ± 14 vs. 23 ± 10 beats per minute increase from baseline; p < 0.01) and rate-pressure product. Patients in the regadenoson group reported less severe symptoms and required less aminophylline. Stress MBF and MFR were not different between the groups (2.2 ± 0.6 vs. 2.1 ± 0.6 ml/min/g, p = 0.39, and 2.9 ± 0.8 vs. 2.8 ± 0.7, p = 0.31, respectively). In the regadenoson group, there was no correlation between stress flow or MFR and body weight or BMI. Despite its administration at a fixed dose, regadenoson results in an absolute increase in MBF which is comparable to that

Dipyridamole-thallium tests are predictive of severe cardiac arrhythmias in patients with left ventricular hypertrophy

International Nuclear Information System (INIS)

Saragoca, M.A.; Canziani, M.E.; Gil, M.A.; Castiglioni, M.L.; Cassiolato, J.L.; Barbieri, A.; Lima, V.C.; Draibe, S.A.; Martinez, E.E.

1991-01-01

In a population of patients with chronic renal failure (CRF) and a high prevalence of left ventricular hypertrophy (LVH) undergoing chronic hemodialysis, the authors investigated the association between the results of dipyridamole-thallium tests (DTTs) and the occurrence of ventricular arrhythmias. They observed a positive significant association between positive DTTs and the occurrence of severe forms of ventricular arrhythmias. A significant association was also observed between the presence of severe LVH and the occurrence of severe ventricular arrhythmias. However, no association was found between the presence of LVH and the positivity of the DTT. As most of their patients with positive DTTs had unimpaired coronary circulations, they conclude that positive DTTs, although falsely indicative of impaired myocardial blood supply, does have an important clinical relevance, indicating increased risk of morbidity (and, possibly, mortality) due to ventricular arrhythmias in a population of CRF patients submitted to chronic renal function replacement program

Comparison of the myocardial blood flow response to regadenoson and dipyridamole: a quantitative analysis in patients referred for clinical {sup 82}Rb myocardial perfusion PET

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Goudarzi, Behnaz; Fukushima, Kenji; Bravo, Paco; Merrill, Jennifer [Johns Hopkins University, Division of Nuclear Medicine, Russell H Morgan Department of Radiology, Baltimore, MD (United States); Bengel, Frank M. [Johns Hopkins University, Division of Nuclear Medicine, Russell H Morgan Department of Radiology, Baltimore, MD (United States); Hannover Medical School, Department of Nuclear Medicine, Hannover (Germany)

2011-10-15

Regadenoson is a novel selective A{sub 2A} adenosine receptor agonist, which is administered as an intravenous bolus at a fixed dose. It is currently not clear if the absolute flow increase in response to this fixed dose is a function of distribution volume in individual patients or if it is generally comparable to the previous standard agents dipyridamole or adenosine, which are dosed based on weight. We used quantitative analysis of clinical {sup 82}Rb PET/CT studies to obtain further insights. A total of 104 subjects with normal clinical rest/stress {sup 82}Rb perfusion PET/CT were included in a retrospective analysis. To rule out confounding factors, none had evidence of prior cardiac disease, ischaemia or infarction, cardiomyopathy, diabetes with insulin use, calcium score >400, renal disease or other significant systemic disease. A group of 52 patients stressed with regadenoson were compared with a group of 52 patients stressed with dipyridamole before regadenoson became available. The groups were matched for clinical characteristics, risk factors and baseline haemodynamics. Myocardial blood flow (MBF) and myocardial flow reserve (MFR) were quantified using a previously validated retention model, after resampling of dynamic studies from list-mode {sup 82}Rb datasets. At rest, heart rate, blood pressure and MBF were comparable between the groups. Regadenoson resulted in a significantly higher heart rate (34 {+-} 14 vs. 23 {+-} 10 beats per minute increase from baseline; p < 0.01) and rate-pressure product. Patients in the regadenoson group reported less severe symptoms and required less aminophylline. Stress MBF and MFR were not different between the groups (2.2 {+-} 0.6 vs. 2.1 {+-} 0.6 ml/min/g, p = 0.39, and 2.9 {+-} 0.8 vs. 2.8 {+-} 0.7, p = 0.31, respectively). In the regadenoson group, there was no correlation between stress flow or MFR and body weight or BMI. Despite its administration at a fixed dose, regadenoson results in an absolute increase in MBF

Assessment of ischemic heart disease by dipyridamole stress electrocardiographic gated myocardial single photon emission computed tomography with technetium-99m tetrofosmin

International Nuclear Information System (INIS)

Kanna, Masahiko; Mitani, Isao; Nakamaru, Masashi; Shibuya, Ken; Takeda, Kazuyoshi; Asahina, Shigeru; Kitamura, Yutaka; Higuma, Kikuhiko; Ishii, Masao

1998-01-01

Simultaneous assessment of stress perfusion and rest function is possible with gated single photon emission computed tomography (SPECT) using stress injected technetium-99m ( 99m Tc) tetrofosmin (TF). The feasibility of dipyridamole stress electrocardiographic gated myocardial SPECT (GSPECT) with TF was examined as an alternative to conventional stress/rest imaging. Fifty-one patients underwent stress GSPECT. 740 MBq of TF was administered 3 min after dipyridamole infusion. GSPECT acquisition was performed one hour after the injection. Additional rest SPECT was performed on another day only in patients with abnormal perfusion on stress images. Perfusion and thickening were analyzed visually on 17 segments of the left ventricle. Percentage of wall thickening (%WT) was also calculated in 17 segments of the polar map. Thirty-two of 51 patients (63%) had normal stress perfusion and normal rest thickening. Nineteen of 51 patients (37%) had abnormal perfusion on stress images. Among 157 abnormal perfusion segments of the 19 patients, 139 segments (89%) had thickening and the rest (11%) had no thickening. %WT was higher in the reversible segments with or without thickening. There was better agreement for the identification of normal segments and the presence of reversibility between stress GSPECT and the conventional stress/rest study in patients without previous myocardial infarction than in those with previous myocardial infarction (89% vs 79%). These results suggest that stress GSPECT may substitute for conventional stress/rest perfusion study in patients without previous myocardial infarction, allowing shorter examination time and lower cost. However, stress GSPECT does not replace the need for rest perfusion study in patients with previous myocardial infarction, because of underestimation of viability, but %WT may eliminate this underestimation. (author)

Comparison of coronary angiography and early oral dipyridamole thallium-201 scintigraphy in patients receiving thrombolytic therapy for acute myocardial infarction

International Nuclear Information System (INIS)

Jain, A.; Hicks, R.R.; Myers, G.H.; McCarthy, J.J.; Perry, J.R.; Adams, K.F.

1990-01-01

We evaluated 50 consecutive patients who received thrombolytic therapy for acute myocardial infarction using thallium-201 single photon emission computed tomography in combination with oral dipyridamole to assess the frequency of residual myocardial ischemia. Thallium studies were performed early after myocardial infarction at a mean of 4.6 days. The time from the onset of chest pain to the administration of thrombolytic therapy was 2.6 hours (range 0.5 to 5.5). Q wave myocardial infarction was evident in 46 patients; four patients had a non-Q wave infarction (anterior infarction in 31 patients and inferior infarction in 19 patients). The serum mean peak creatinine kinase was 1503 IU/L (range 127 to 6500). Coronary angiography was performed in all patients at a mean of 3.1 days (range 2 to 10) and revealed the infarct-related vessel to be patent in 36 patients (72%). The ejection fraction was 48% (range 26% to 67%). After dipyridamole administration, 13 patients (26%) developed angina that was easily reversed with the administration of intravenous aminophylline. Systolic blood pressure decreased from 122 to 115 mm Hg (p less than 0.05) and the heart rate increased from 76 to 85 beats/min (p less than 0.05). None of the patients had significant hypotension, arrhythmias, or evidence of infarct extension. Perfusion abnormalities were present on the initial thallium images in 48 patients. Redistribution suggestive of ischemia was present in 36 patients (72%). Ischemia confined to the vascular distribution of the infarct vessel was evident in 22 patients. Seven patients had ischemia in the infarct zone as well as in a remote myocardial segment. Thus 29 patients (58%) had ischemia in the distribution of the infarct vessel. Ischemia in the infarct zone was evident in 19 of 36 patients with open infarct vessels and in 10 of 14 patients with occluded infarct vessels

Dipyridamole thallium-201 single-photon emission computed tomography for prediction of perioperative cardiac events in patients with arteriosclerosis obliterans undergoing vascular surgery

International Nuclear Information System (INIS)

Ziyang, Huang; Komori, Sadayoshi; Sawanobori, Takao

1998-01-01

The aim of the study was to determine whether or not dipyridamole thallium-201 single-photon emission computed tomography ( 201 Tl-SPECT) has significant additive value for predicting perioperative cardiac events in patients with arteriosclerosis obliterans (ASO) undergoing vascular surgery. Routine preoperative 201 Tl-SPECT was performed in 106 consecutive patients with ASO (age 68±8.9 years; 91 men and 15 women). The frequency of reversible defects in a clinical high-risk group (n=44) was significantly higher than in a low-risk group (n=62; 55% vs 24%, p 201 Tl-SPECT data to clinical risk-stratified patients with ASO allows better prediction of perioperative cardiac events. (author)

Noninvasive detection of coronary artery disease by dipyridamole-loading 201thallium myocardial scintigraphy

International Nuclear Information System (INIS)

Hamashige, Naohisa; Doi, Yoshinori; Yonezawa, Yoshihiro; Odawara, Hiroaki; Ozawa, Toshio; Akagi, Naoki; Yoshida, Shoji; Maeda, Tomoho

1986-01-01

Fifty patients with suspected coronary artery disease (CAD) were given i.v. infusion of 0.568 mg/kg of dipyridamole (DP) for 4 min in the supine position, and were loaded by stepping. Myocardial DP scanning (DP scintigraphy) was then performed with i.v. injection of 3 mCi of Tl-201 chloride. Findings were compared with those of coronary angiography and treadmill ECG. DP scintigraphy had higher sensitivity (90 %) and specificity (95 %) than treadmill ECG (76 % and 67 %) in diagnosing a ≥ 75 % coronary stenosis. Twenty nine patients had significant CAD: Reversible defects were associated with chest pain in 79 %, and with ST depression in 76 %. Not only relative differences in blood flow between the normal and diseased sites but also ischemia was suggested to be responsible for these defects. Increased rate pressure product by DP scintigraphy was slight (34 %) compared with that by treadmill ECG (105 %), suggesting a strong involvement of redistribution of coronary blood flow in the occurrence of ischemia. Increased myocardial oxygen consumption due to stepping was considered as the cause of ischemia as well, because the incidence of chest pain and ST depression was higher than previously reported. Chest pain and ST depression improved by i.v. injection of aminophylline. (Namekawa, K.)

Withholding or Continuing Beta-Blocker Treatment Before Dipyridamole Myocardial Perfusion Imaging for the Diagnosis of Coronary Artery Disease? a Randomized Clinical Trial

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Babak Fallahi

2013-01-01

Full Text Available Although it has been shown that acute beta-blocker administration may reduce the presence or severity of myocardial perfusion defects with dipyridamole stress, little information is available about the potential effect of chronic beta-blocker treatment on the sensitivity of dipyridamole myocardial perfusion imaging (DMPI.Methods As a randomized clinical trial, one hundred twenty patients (103 male and 17 female with angiographically confirmed CAD who were on long-term beta blocker therapy ([greater than or equal to]3 months enrolled in a randomized clinical trial study. The patients were allocated into two groups: Group A (n=60 in whom the beta-blocker agent was discontinued for 72h before DMPI and Group B (n=60 without discontinuation of beta-blockers prior to DMPI.ResultsNo significant difference was noted between the groups concerning age, sex, type of the injected radiotracer and number of involved coronary vessels. The mean rank of total perfusion scores for whole myocardium (irrespective of reversibility or irreversibility in group B was not significantly different from that of group A, (65.75 vs. 55.25, P=0.096. Regarding the only irreversible perfusion defects, the mean rank of perfusion score in group B was higher than that of group A for whole myocardium (72 vs. 49, P=0.0001; however, no difference was noted between two groups for only reversible perfusion defects (61.0 vs. 60.0, P=0.898. The overall sensitivity of DMPI for the diagnosis of CAD in group A (91.7% was not statistically different from group B (90%.ConclusionBeta-blocker withholding before DMPI did not generally affect the sensitivity of the test for the diagnostic purposes in our study. Thus, beta-blocker withdrawal for just the purpose of diagnostic imaging is not mandatory particularly when medication discontinuation may cause the patients to face increased risk of heart events.

Clinical assessment of first pass radionuclide ventriculography after dipyridamole infusion in patients with coronary artery disease

International Nuclear Information System (INIS)

Kanaya, Tohru; Tono-oka, Ichiro; Satoh, Satoshi; Yamaguchi, Yoshiko; Hoshi, Hikaru; Ikeda, Kozue; Tsuiki, Kai; Yasui, Shoji; Komatani, Akio

1986-01-01

First pass radionuclide ventriculography (RNV) was performed after dipyridamole (D) infusion in 33 patients with coronary artery disease (CAD) and 15 normal volunteers. RNV findings after D infusion were compared with those of conventional exercise RNV and body surface ECG mapping (MAP). For patients with multiple vessel disease, left ventricular ejection fraction (LVEF) was significantly lower after D infusion than at rest. Wall motion abnormality (WMA) sites induced by D infusion were well coincident with those induced by exercise. Pressure rate product at exercise was significantly higher than that after D infusion, suggesting the different mechanism of the occurrence of WMA after D infusion and at exercise. The incidence of ischemic reaction tended to be higher after D infusion than at exercise in 25 patients with CAD. There was negative correlation between ST depression on MAP after D infusion and LVEF on RNV after D infusion. This RNV after D infusion can be used as a supplement tool to conventional exercise RNV in the evaluation of the degree of coronary artery lesions and preserved left ventricular function. (Namekawa, K.)

Controlled release profiles of dipyridamole from biodegradable microspheres on the base of poly(3-hydroxybutyrate.

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2007-12-01

Full Text Available Novel biodegradable microspheres on the base of poly(3-hydroxybutyrate (PHB designed for controlled release of antithrombotic drug, namely dipyridamole (DPD, have been kinetically studied. The profiles of release from the microspheres with different diameters 4, 9, 63, and 92 µm present the progression of nonlinear and linear stages. Diffusionkinetic equation describing both linear (PHB hydrolysis and nonlinear (diffusion stages of the DPD release profiles from the spherical subjects has been written down as the sum of two terms: desorption from the homogeneous sphere in accordance with diffusion mechanism and the zero-order release. In contrast to the diffusivity dependence on microsphere size, the constant characteristics (k of linearity are scarcely affected by the diameter of PHB microparticles. The view of the kinetic profiles as well as the low rate of DPD release are in satisfactory agreement with kinetics of weight loss measured in vitro for the PHB films. Taking into account kinetic results, we suppose that the degradation of both films and PHB microspheres is responsible for the linear stage of DPD release profiles. In the nearest future, combination of biodegradable PHB and DPD as a representative of proliferation cell inhibitors will give possibility to elaborate the novel injectable therapeutic system for a local, long-term, antiproliferative action.

Predictors of abnormal heart rate response to dipyridamole in patients undergoing myocardial perfusion SPECT

International Nuclear Information System (INIS)

De Souza Leao Lima, R.; Machado, L.; Azevedo, A.B.; De Lorenzo, A.

2011-01-01

The objective of this study was to identify predictors of abnormal HR response to dipyridamole (DIP) in patients undergoing myocardial perfusion SPECT (MPS). Patients with a reduced heart rate (HR) response to DIP have higher cardiac mortality, but the mechanism is unknown. We studied 432 patients who underwent dual-isotope gated MPS. DIP (0.56 mg/kg) was infused over 4 min, and Tc-99m tetrofosmin was injected 3 min after the end of the infusion. MPS was semiquantitatively interpreted. Left ventricular ejection fraction (LVEF) and volumes were automatically calculated. The population was categorized into quartiles according to HR ratio, and characteristics in each quartile were compared. Logistic regression analysis was performed to identify predictors of abnormal HR response, using the lowest quartile as the independent variable. Patients with abnormal HR response were more frequently without chest pain, with a history of chronic renal failure and taking digoxin. Baseline HR was higher and had fewer symptoms during stress. The stress and rest perfusion defects were greater, but reversibility was not; in addition, LVEF was lower. Multivariable logistic regression analysis demonstrated that the independent predictors of abnormal HR response were baseline HR and low LVEF. LV dysfunction is an independent predictor of abnormal HR response to DIP, and the association between low LVEF and low HR ratio may explain the link between abnormal HR ratio and increased mortality. (author)

Comparison of oral and intravenous routes of administration of dipyridamole for thallium imaging of type I diabetics with end-stage renal disease

International Nuclear Information System (INIS)

Boudreau, R.J.; Stony, J.T.; du Cret, R.P.; Kuni, C.C.; Wang, Y.; Wilson, R.F.; Schwartz, J.F.; Castaneda-Zuniga, W.R.

1989-01-01

The authors have frequently seen myocardial infarction after renal transplantation in patient with type I diabetes, and treadmill T1-201 testing in these patients have been inadequate. The authors evaluated dipyridamole (DP) as a substitute for treadmill stress. Because intravenous DP was not approved in the United States at the time of the study, the oral formulation wax used for some patients. The authors have prospectively evaluated 80 uremic diabetics (40 received oral T1-201; 40 received intravenous T1-201). Angiogram and scan observers were blinded. There was not difference in the accuracy of the two routes of administration. Pooling the data gave a sensitivity of 86% and a specificity of 79%. However, their disease prevalence was high (52%), which precluded the use of any screening test. The authors now have recommended angiography for these patients

Usefulness of 201Tl myocardial scintigraphy after dipyridamole infusion in patients with atherosclerotic vascular disease

International Nuclear Information System (INIS)

Toyama, Takuji; Nishimura, Tsunehiko; Uehara, Toshiisa

1992-01-01

To determine the utility for detecting ischemic heart disease (IHD), dipyridamole thallium myocardial images (DIP-Tl) have been performed in 103 patients with atherosclerotic vascular disease who can't exercise fully. Of the 103 patients, there were 36 patients with arteriosclerosis obliterans (ASO), 31 patients with aneurysm of the abdominal aorta (AAA), 24 patients with aneurysm of the thoracic aorta (TAA) and 12 patients with dissecting aortic aneurysm (DAA). Clinical evidence of IHD was found in 20 patients with ASO, 10 with AAA, 7 with TAA and 4 with DAA. Positive evidence of DIP-Tl was identified in 66% of 41 patients who had clinical evidence of IHD, and particularly in the patients with AAA (80%) and ASO (65%). On the other hand, in the patients without clinical evidence of IHD, positive evidence of DIP-Tl was identified in 19% of 62 patients and particularly in the patients with AAA (39%). In all patients, the percentage of the positive DIP-Tl ratio was 38%. And, when the 38% patients of the positive DIP-Tl were added to the patients of the negative DIP-Tl who had clinical evidence of IHD, almost half patients (51%) were considered to be complicated with IHD. This study suggests that the atherosclerotic vascular disease is highly complicated with IHD and DIP-Tl is useful to detect IHD. (author)

Technetium 99m SESTAMIBI myocardial perfusion imaging: Comparison between treadmill, dipyridamole and trans-oesophageal atrial pacing 'stress' tests in normal subjects

International Nuclear Information System (INIS)

Primeau, M.; Taillefer, R.; Lambert, R.; Essiambre, R.; Honos, G.

1991-01-01

The purpose of this study was to determine the blood clearance, myocardial uptake and heart/lung and heart/liver ratios of technetium 99m methoxyisobutylisonitrile ( 99m Tc-SESTAMIBI) following 3 different types of cardiac stimulation in normal subjects: Treadmill stress (STRESS), intravenous administration of dipyridamole (DIP) and trans-oesophageal atrial pacing (TAP). Ten normal volunteers were submitted to 3 injections of 99m Tc-SESTAMIBI (10 mCi/70 kg, separated by an interval of 7 days) following STRESS (standard Bruce protocol), DIP (0.142 mg/kg.min during 4 min) and TAP procedures. Blood samples were collected from 1 to 60 min after each 99m Tc-SESTAMIBI injection. Planar imaging was performed at 5, 30 and 60 min. Blood retention (percentage of injected dose at 1 min) was 56%±4%, 24%±4% and 38%±6% for STRESS, DIP and TAP, respectively (P 99m Tc-SESTAMIBI. (orig.)

Dipyridamole induced directory disfunction of infarcted vessel, and estimation of patients with acute myocardial infarction and successful PTCA

International Nuclear Information System (INIS)

Hashimoto, Yasunori; Yamabe, Hiroshi; Kim, Sushik; Yano, Takashi; Fujita, Hideki; Kakimoto, Tetsuya; Namura, Hiroyuki; Maeda, Kazumi; Yokoyama, Mitsuhiro

1993-01-01

The purpose of this study was to determine whether transient disturbance of vascular dilation in the peripheral coronary vessels in patients with myocardial infarction in whom coronary recanalization was successfully attained in the acute stage. The subjects were 6 patients with acute myocardial infarction in whom recanalization was successfully attained without a significant coronary stenosis by emergency percutaneous transluminal coronary angioplasty (PTCA). Dipyridamole-loaded thallium-201 myocardial scintigraphy was undertaken during the acute stage (an average of 5 days after PTCA) and during convalescent stage (an average 24 days after PTCA). Defect was seen in the infarcted areas on early images during the acute stage in all 6 patients, and Tl uptake in the infarcted areas was improved during the convalescent stage in 2 of the 6 patients. In these two patients, fill-in phenomenon was seen in the infarcted area during acute stage when images were acquired after re-injection of Tl-201. These findings suggested that transient disturbance of vascular dilation may occur in the peripheral coronary artery vessels in the infarcted area where recanalization was successfully attained in patients with acute myocardial infarction. (N.K.)

The relationship between chest pain during thallium-201 scintigraphy with dipyridamole and myocardial ischemia

International Nuclear Information System (INIS)

Takeishi, Yasuchika; Tono-oka, Ichiro; Meguro, Mitsuhiko; Hoshi, Hikaru; Masakane, Ikuto; Ikeda, Kozue; Tsuiki, Kai; Yasui, Shoji

1991-01-01

Dipyridamole thallium-201 scintigraphy (DP-Tl) and coronary angiography were studied on 74 patients with suspected coronary artery disease. We compared the clinical features, hemodynamic responses, angiographic results and scintigraphic findings of patients who had chest pain during DP-Tl testing ('chest pain' group) with those of patients who did not have chest pain ('no pain' group). Thirty eight (51%) of the 74 patients developed chest pain. Heart rate and rate pressure product during DP infusion of 'chest pain' group were greater than those of the 'no pain' group (p<0.05). Ischemic ST depression was more frequently observed among 'chest pain' patients (p<0.01). There were no differences in angiographic severity of coronary artery disease between 'chest pain' and 'no pain' group. Also, we could find no differences in extent and severity scores of perfusion defects and washout abnormalities between the two groups. However, when patients with myocardial infarction were excluded, the 'chest pain' group had significantly greater extent and severity scores of washout abnormalities than the 'no pain' group (extent score: 38±8 vs 18±5, p<0.05, severity score: 55±15 vs 18±7, p<0.01). Our study indicated that in patients without myocardial infarction, patients with 'chest pain' had more severe ischemia than 'no pain' patients. But in patients with myocardial infarction, myocardial ischemia not accompanied by chest pain might be as severe as that with chest pain. The presence or absence of myocardial infarction might have great influence on results regarding the relation of chest pain to myocardial ischemia. (author)

Left ventricular function in response to dipyridamole stress: head-to-head comparison between {sup 82}Rubidium PET and {sup 99m}Tc-sestamibi SPECT ECG-gated myocardial perfusion imaging

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Giorgi, Maria Clementina; Meneghetti, Jose Claudio; Soares, Jose; Izaki, Marisa; Falcao, Andrea; Imada, Rodrigo; Chalela, William; Oliveira, Marco Antonio de; Nomura, Cesar [Department of Radiology and Nuclear Medicine and Molecular Imaging Service - Heart Institute of the University of Sao Paulo Medical School, Sao Paulo (Brazil); Verberne, Hein J. [University of Amsterdam, Department of Nuclear Medicine, Academic Medical Center, P.O. Box 22700, Amsterdam (Netherlands)

2017-05-15

Myocardial perfusion imaging (MPI) with {sup 99m}Tc-sestamibi (sestamibi) SPECT and rubidium-82 ({sup 82}Rb) PET both allow for combined assessment of perfusion and left ventricular (LV) function. We sought to compare parameters of LV function obtained with both methods using a single dipyridamole stress dose. A group of 221 consecutive patients (65.2 ± 10.4 years, 52.9% male) underwent consecutive sestamibi and {sup 82}Rb MPI after a single dipyridamole stress dose. Sestamibi and {sup 82}Rb summed rest (SRS), stress (SSS) and difference (SDS) scores, and LV end-diastolic (EDV) and end-systolic (ESV) volumes and left ventricular ejection fraction (LVEF) were compared. Bland-Altman analysis showed that with increasing ESV and EDV the difference between the two perfusion tracers increased both at rest and post-stress. The mean difference in EDV and ESV between the two perfusion tracers at rest could both be independently explained by the {sup 82}Rb SDS and the sestamibi SRS. The combined models explained approximately 30% of the variation in these volumes between the two perfusion tracers (R{sup 2} = 0.261, p = 0.005; R{sup 2} = 0.296, p < 0.001, for EDV and ESV respectively). However, the mean difference in LVEF between sestamibi and {sup 82}Rb showed no significant trend post-stress (R{sup 2} = 0.001, p = 0.70) and only a modest linear increase with increasing LVEF values at rest (R{sup 2} = 0.032, p = 0.009). Differences in left ventricular volumes between sestamibi and {sup 82}Rb MPI increase with increasing volumes. However, these differences did only marginally affect LVEF between sestamibi and {sup 82}Rb. In clinical practice these results should be taken into account when comparing functional derived parameters between sestamibi and {sup 82}Rb MPI. (orig.)

Semiquantitative SPECT myocardial perfusion with dipyridamole in patients unable to exercise. Event rate during 4 years of follow up

International Nuclear Information System (INIS)

Balestrini, V.R.; Arja, V.J.; Sandrin, A.L.; Calvo, G.R.; Gomez Bosh, Z.; Quiroga, W.; Balestrini, C.E.; Joekes, S.

2002-01-01

The increasingly numbers of patients (P) that can't reach an adequate level of exercise in order to evaluate CAD, lead us to use pharmacological and technical tools available for this subgroup of P. Aim: evaluate the prognostic significance of myocardial perfusion SPECT imaging with pharmacological stress in P without LBBB, unable to exercise. Material and Methods: 209 P were included. Mean age: 65 years old (39-88), male 66%. Clinical: Pre test likelihood 8: 28%; SDS 0 and SRS 0: 31.7%; SDS 0 + SRS >=1: 21%; SDS >=1: 47.3%. III) Follow up: 13 patients were early re-vascularized induced by SPECT study results, 10 patients get lost and 186 were follow up by a mean 1086 days. Cumulative events rate: 1st year SCE 9.7%, HCE 1.6%; 2nd year SCE 14%, HCE 4.3%; 3rd year SCE 17.7%, HCE 5.4%; 4th year SCE 21%, HCE 5,4%. Scintigraphic indices and events rate relationship are presented. Conclusion: There was a relationship between scintigraphic indices and hard cardiac events. The semiquantitative myocardial perfusion with dipyridamole stress was a safe test and useful to discriminate groups of P with different risk of events

Tomographic thallium-201 myocardial perfusion scintigrams after maximal coronary artery vasodilation with intravenous dipyridamole: comparison of qualitative and quantitative approaches

International Nuclear Information System (INIS)

Francisco, D.A.; Collins, S.M.; Go, R.T.; Ehrhardt, J.C.; Van Kirk, O.C.; Marcus, M.L.

1982-01-01

Eighty-six patients had thallium-201 ( 201 Tl) myocardial perfusion scintigrams after intense coronary artery dilation with i.v. dipyridamole. Tomographic and planar 201 Tl scintigrams were obtained in each patient. Tomographic scintigrams were interpreted using quantitative or visual criteria; planar scintigrams were assessed using visual criteria only. When visual criteria were used, interobserver variability was 40% for tomographic scintigrams and 44% for planar scintigrams. In the 24 patients with normal or nonsignificant CAD, quantitative analysis of the tomograms (range approach) indicated that one of 24 (4%) had a positive image (specificity 96%%); in contrast, when visual criteria were used to interpret the tomographic or planar 201 Tl scintigrams, eight of 24 (33%) had positive scintigrams (specificity 67%). In the 51 abnormal patients, the sensitivity of detecting CAD was 46 of 51 (90%) for tomographic scintigrams interpreted quantitatively, 39 of 51 (76%) for tomographic scintigrams interpreted visually and 41 of 51 (80%) for planar scintigrams assessed visually. The tomographic imaging procedure (quantitative interpretation) also demonstrated a high sensitivity (89%) and specificity (100%) in 28 patients (10 normal and 18 CAD), with a clinical diagnosis of unstable angina pectoris. Overall, the predictive accuracy of an abnormal scintigram with quantitative tomographic imaging (98%) was significantly better (p<0.05) than either qualitative planar or pinhole imaging

Analysis of structure of hyperfine poly(3-hydroxybutyrate) fibers (PHB) for controlled drug delivery

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Olkhov, A. A.; Kosenko, R. Yu; Markin, V. S.; Zykova, A. K.; Pantyukhov, P. V.; Karpova, S. G.; Iordanskii, A. L.

2017-12-01

Hyperfine fibers based on biodegradable poly (3-hydroxybutyrate) with encapsulated drug substance (dipyridamol) were obtained by using electrospinning method. Addition of dipyridamol has a significant effect on geometrical shape and structure of microfibers as well as total porosity of fibrous material. Observation of fibers using scanning electron microscopy (SEM) method showed that without or at lower dipyridamol content (<3%) fibers consisted of interleaved ellipsoid and cylindrical fragments. At higher dipyridamol content (3-5%) anomalous ellipsoid structures did not practically form, and fiber’s shape became cylindrical. The totality of morphological and structural characteristics determined the rate of dipyridamol diffusive transports. The simplified model of drug desorption from fibrous matrix was presented. In current work it was showed that the rate-limiting stage of transport was the diffusion of dipyridamol in the bulk of cylindrical fibers.

Optimization of perfusion studies using Atropine

International Nuclear Information System (INIS)

Alvarado, A.N.; Valle, V.M.; Montoya, M.J.; Eskenazi, E.S.; Montiel, M.L.; Cueto, C.C.

2002-01-01

The studies of myocardial perfusion require an adequate stress; exercise or pharmacological. Every day, more pharmacological studies are performed, specially in some group of patients (women, AMI, etc). There some drugs that are used for this purpose, as adenosine and dobutamine. However, their cost and the lack of availability and infrastructure in our country do not allow there routinely use. We performed dipyridamol as a pharmacological stress, however in some patients there is a doubt regarding if the pharmacological effect was adequate. Atropine is a drug that is frequently used for different purpose and it is well know its tachycardic response. We present and alternative technique, using dipyridamol-atropine as a protocol of stress perfusion study. Our goal was to correlate the standard dipyridamol -thallium perfusion study and the dipyridamol -atropine-perfusion in patients with chronic coronary disease. We evaluated 6 patients (5 males) with stable angina and chronic coronary disease. A standard dipyridamol-thallium study was performed in all of them. Dipyridamole was administered intravenously at a rate of 0.14 mg/kg/min over 6 min for a total of 0.84 mg/kg body weight. Blood pressure, heart rate, EKG and symptoms were monitored before, during and after the pharmacological infusion. Two minutes after the infusion was completed, the radiotracer was injected intravenously. In the next 6 months, without any modification of the clinical situation (symptoms and therapy) a new dipyridamol study was performed, using 1 mg of atropine after the administration of dipyridamol. There were no differences in the collateral effects and we observed and average increase of 30% in the heart rate in relation with the study using dipyridamol alone. The addition of atropine to the standard dipyridamol perfusion study is safe, cheaper and improved the detection of perfusion defects in patients with coronary artery disease

Comparison of myocardial blood flow induced by adenosine triphosphate and dipyridamole in patients with coronary artery disease

International Nuclear Information System (INIS)

Mamede, M.; Tadamura, Eiji; Hosokawa, Ryohei

2005-01-01

Myocardial perfusion imaging with adenosine triphosphate (ATP) has been used increasingly to diagnose coronary artery disease (CAD) and assess risk for this disease. This study compared absolute myocardial blood flow (MBF) and myocardial flow reserve index (MFR) with ATP and dipyridamole (DIP) in patients with CAD. MBF was quantified by 15 O-H 2 O PET in 21 patients with CAD (17 male, 4 female), aged 55 to 81 years. MBF was measured at rest, during intravenous injection of ATP (0.16 mg/kg/min), and again after DIP infusion (0.56 mg/kg). Regions of interest were drawn in nonischemic and ischemic segments based on findings from thallium-201 ( 201 Tl) scintigraphy and coronary angiography (CAG). Absolute MBF values and indexes of MFR were calculated in nonischemic and ischemic segments. Intravenous injection of ATP and DIP significantly increased MBF in nonischemic (2.4±0.9 and 2.1±0.8 ml/g/min, respectively; p<0.01, for both) and in ischemic segments (1.3±0.4 and 1.5±0.4 ml/g/min, respectively; p<0.01, for both). There was a significant difference in MBF values between ATP and DIP in nonischemic segments (p<0.05), which was not observed in ischemic segments. In nonischemic segments, ATP produced higher MFR than DIP (2.1±0.8 and 1.8±0.7, respectively; p<0.05), while no significant difference was observed in ischemic segments (1.5±0.6 and 1.7±0.3, respectively). ATP produced a greater hyperemia than DIP between the ischemic and nonischemic myocardium in patients with CAD. ATP is as effective as DIP for the diagnosis of CAD. (author)

High-dose cisplatin with dipyridamole in advanced non-small cell lung cancer. A Grupo Oncológico Cooperativo del Sur study.

Science.gov (United States)

Vallejo, C T; Rabinovich, M G; Perez, J E; Rodriguez, R; Machiavelli, M R; Leone, B A; Romero, A D; Lacava, J A; Cuevas, M A; Langhi, M J

1995-06-01

From March 1991 to October 1992, 41 patients with advanced non-small cell lung cancer (NSCLC) (20 stage IIIB and 21 stage IV) received a regimen consisting of cisplatin (CP) 100 mg/m2 i.v. days 1 and 8, and dipyridamole (DPD) 100 mg p.o. 75 minutes before CP, and then at hours 6, 12, and 18 as first-line chemotherapy. Cycles were repeated every 28 days for a total of 3. Median age was 56 years (range: 40-70). All patients had a performance status 0 to 1 and a weight loss < or = 10%. Squamous-cell carcinoma was diagnosed in 19 patients; adenocarcinoma in 16, and large-cell carcinoma in 6. A total of 37 patients were fully evaluable for response, whereas 39 were assessable for toxicity. No complete responses were observed: 5 patients (14%) achieved partial response; 23 patients (62%) showed no change, and progressive disease was observed in 9 (24%). The median time to treatment failure was 4 months, whereas median survival was 8 months. The average dose intensity received at the end of the third course of therapy was 46 mg/m2/week. There were no drug-related deaths. Toxicity was mild to moderate, with a high incidence of ototoxicity (54%) and emesis (67%). In conclusion, these results failed to demonstrate any significant advantage from a high-dose CP regimen modulated by DPD in patients with advanced NSCLC.

The study of myocardial ischemic quality with weighted-subtraction-bull's-eye analysis

International Nuclear Information System (INIS)

Chen Wuduan; Tian Jiahe; Hou Qingtian

1993-01-01

Weighted-Subtraction-Bull's-eye analysis was studied in 33 normal subjects and 58 patients with coronary artery disease after dipyridamole 99m Tc-MIBI myocardial SPECT imaging. Two kinds of Bull's-eye were produced: (1) subtract rest from 1.2 times dipyridamole from 1.2 times rest Bull's-eye; (2) subtract dipyridamole Bull's-eye. The results showed that the weighted-subtraction-Bull's-eye could clearly displayed the location and puality of ischemic myocardium. And also 74% segments showed so called combined ischemic i.e the blood perfusion reduced, increased and sustained simultaneously after dipyridamole. Therefore weighted-subtraction-Bull's-eye analysis had provided a new method for determination of the quality of ischemia

Radioprotective efficacy of dipyridamole and AMP combination in fractionated radiation regimen, and its dependence on the time of administration of the drugs prior to irradiation

International Nuclear Information System (INIS)

Hofer, M.; Pospisil, M.; Netikova, J.; Hola, J.; Znojil, V.; Vacha, J.

1995-01-01

The authors have recently demonstrated that a combined administration of dipyridamole and adenosine monophosphate to mice induces radioprotective effects in terms of postirradiation hematopoietic recovery in animals irradiated with a single dose. The aim of the present experiments was to investigate the radioprotective ability of the drug combination under conditions of fractionated radiation. It was shown that administration of the drugs either 15 or 60 min before each of the five daily 3-Gy doses of gamma radiation enhances hematopoietic recovery and survival of mice exposed to an additional 'top-up' dose of 3.5 Gy. Furthermore, it was ascertained that administration of the drugs 60 min prior to irradiation is more effective than administration of the drugs 15 min prior to irradiation. Due to the evidence that administration of the drugs 15 min prior to irradiation protects the organism mainly via mechanisms of systemic hypoxia while the pretreatment 60 min before irradiation avoids the role of hypoxia and mainly induces cell proliferation effects, the present results suggest a more protective role of mechanisms stimulating hematopoiesis under conditions of fractionated radiation. The data may provide a basis for more rational use of radioprotection in fractionated radiation techniques. (author) 1 tab., 1 fig., 25 refs

Effect of preoperative antiplatelet drugs on vascular prostacyclin synthesis.

Science.gov (United States)

Karwande, S V; Weksler, B B; Gay, W A; Subramanian, V A

1987-03-01

Patients undergoing aortocoronary bypass using autogenous saphenous veins were randomly divided into three comparable groups. Group 1 (n = 10) acted as a control, Group 2 (n = 14) received 80 mg of aspirin at midnight before the operation, and Group 3 (n = 12) received 80 mg of aspirin and 75 mg of dipyridamole at midnight and an additional 75-mg dose of dipyridamole at 6 AM. The purpose was to determine which regimen would maximally inhibit platelet function without depressing vascular prostacyclin synthesis. Serum thromboxane A2, saphenous vein wall and aortic wall prostacyclin, platelet aggregation, and bleeding time were measured in all patients. None was restarted on a regimen of aspirin or dipyridamole postoperatively. Aspirin alone and in combination with dipyridamole significantly inhibited thromboxane A2 and platelet aggregation in all treated patients but spared venous prostacyclin synthesis. Aortic prostacyclin synthesis was partially inhibited in both treated groups. Chest tube drainage was comparable in all three groups. These results indicate that the combination of aspirin and dipyridamole offers no measurable advantage over aspirin alone in the perioperative period.

Physiological assessment of sensitivity of noninvasive testing for coronary artery disease

International Nuclear Information System (INIS)

Simonetti, I.; Rezai, K.; Rossen, J.D.; Winniford, M.D.; Talman, C.L.; Hollenberg, M.; Kirchner, P.T.; Marcus, M.L.

1991-01-01

The sensitivity of three noninvasive tests for coronary artery disease was assessed by means of quantitative indexes of disease severity in three different groups of patients. The overall population consisted of 110 subjects with limited coronary artery disease and no myocardial infarction. Planar dipyridamole- 201 Tl scintigraphy was evaluated in 31 patients, computer-assisted exercise treadmill in 28, and high-dose dipyridamole echocardiography testing in 51. Sensitivity was assessed by rigorous gold standards to define disease severity, such as measurement of minimum cross-sectional area and percent area of stenosis, by quantitative computerized coronary angiography (Brown/Dodge method). On the basis of the results of previous studies, the presence of physiologically significant coronary artery disease was indicated by a stenotic minimum cross-sectional area (MCSA) of less than 2.0 mm 2 or a greater than 75% area of stenosis. With MCSA as the gold standard, dipyridamole- 201 Tl scintigraphy, computerized exercise treadmill, and dipyridamole echocardiography testing showed sensitivities of 52%, 54%, and 61%, respectively, in the three different patient cohorts enrolled. With percent area of stenosis as the gold standard, the sensitivity figures obtained for dipyridamole- 201 Tl, computerized exercise treadmill, and dipyridamole echocardiography testing were 64%, 54%, and 69%, respectively. For each of the three tests, sensitivity increased with increasing lesion severity. Sensitivity was also better in patients with left anterior descending coronary (LAD) disease when compared with patients with left circumflex or right coronary artery disease. Results of these studies demonstrate that in patients with limited coronary artery disease none of the tests evaluated is definitely superior in sensitivity

Preparation and in vitro-in vivo evaluation of none gastric resident dipyridamole (DIP) sustained-release pellets with enhanced bioavailability.

Science.gov (United States)

Xu, Lishuang; Luo, Yanfei; Feng, Jia; Xu, Ming; Tao, Xiaoguang; He, Haibing; Tang, Xing

2012-01-17

The objective of this study was to develop none gastric resident sustained-release pellets loaded with dipyridamole with a high bioavailability. Two different kinds of core pellets, one containing citric acid as a pH-modifier (CAP) and, the other without pH-modifier (NCAP) were prepared by extrusion-spheronization and then coated with mixtures of enteric soluble and insoluble polymers (referred to as CAP(1) and NCAP(1)) or insoluble polymer alone (referred to as CAP(2) and NCAP(2)). The relative bioavailability of the sustained-release pellets was studied in fasted beagle dogs after oral administration using a commercially available immediate release tablet (IRT) as a reference. The in vitro release, in vivo absorption and in vitro-in vivo correlation were also evaluated. Results revealed that the plasma drug concentrations after administration of CAP(2), NCAP(1) and NCAP(2) were undetectable, indicating that the drug release was almost zero from the preparations throughout the gastro-intestinal tract. The C(max), T(max) and AUC((0→24)) of CAP(1) were 0.78 ± 0.23 (μg/ml), 3.80 ± 0.30 (h), and 6.74 ± 0.47 (μg/mlh), respectively. While the corresponding values were 2.23 ± 0.32 (μg/ml), 3.00 ± 0.44 (h) and 9.42 ± 0.69 (μg/mlh) for IRT. The relative bioavailability of CAP(1) was 71.55% compared with IRT. By combined incorporation of a pH-modifier into the core of pellets to modify the inner micro-environment and employing mixtures of enteric soluble and insoluble polymers as a retarding layer, drugs with high solubility in stomach and limited solubility in small intestine, such as DIP, could be successfully formulated as sustained release preparations with no pH-dependence in drug release and enhanced bioavailability. Copyright © 2011 Elsevier B.V. All rights reserved.

Pharmacological radionuclide ventriculography for detection of myocardial contractile reserve in patients after myocardial infarction: head-to-head comparison of low dose dobutamine and low dose dypiridamole

International Nuclear Information System (INIS)

Petrasinovic, Z.; Ostojic, M.; Beleslin, B.; Stojkovic, S.; Nedeljkovic, M.; Stankovic, G.; Dikic, A.; Pavlovic, S.; Sobic, D.

2002-01-01

Background. Low dose pharmacological stress echocardiography with either dobutamine or dipyridamole infusion has been proposed for recognition of myocardial viability. However, dependence on adequate acoustic window, observer experience, and the mild degree of wall motion changes make the viability assessment by stress echocardiography especially bothersome. The objective of the study was to evaluate the ability of low dose dobutamine and low dose dipyridamole radionuclide ventriculography to detect contractile reserve in patients after myocardial infarction and functional recovery after coronary angioplasty. Methods. The study group consisted of 20 consecutive patients (52±10 years, 17 male) with previous myocardial infarction and resting regional dyssynergy, in whom diagnostic cardiac catheterization revealed significant one-vessel coronary artery stenosis suitable for angioplasty. Each patient underwent equilibrium 99m-Tc radionuclide ventriculography which was performed at rest and during low dose dipyridamole (0.28 mg/kg over 2 minutes) and low dose dobutamine infusion (up to 10 mcg/kg/min). Left ventricular global and regional ejection fractions were determined. Increase of regional ejection fraction for >5% (inferoapical and posterolateral regions) or >10% (anteroseptal regions) during low dose dobutamine and dipyridamole in infarcted regions, as well as in the follow up period, was considered as index of contractile reserve. After 8 weeks of successful angioplasty, resting radionuclide ventriculography was repeated in all patients in order to identify functional recovery of the infarct zone. Results. Out of the 180 analyzed segments (20x9), 90 regional ejection fractions have shown depressed contractility. The mean of the regional ejection fractions showing depressed contractility increased from the resting value of 34±12% to 42±14% in the follow-up period (p=0.06). Of the 90 with baseline dyssynergy, 46 were responders during low-dose dobutamine (51

Stress magnetic resonance imaging in coronary artery disease. 11

International Nuclear Information System (INIS)

Pennell, D.J.; Underwood, S.R.

1991-01-01

The feasibility of MRI of wall motion and cardiovascular haemodynamics has been investigated during pharmacological stress with dipyridamole and dobutamine as pharmacological stressors. The authors conclude that dobutamine is preferable to dipyridamole for inducing myocardial ischemia during imaging. (H.W.). 74 refs.; 8 figs.; 5 tabs

Reverse 201Tl myocardial redistribution induced by coronary artery spasm

International Nuclear Information System (INIS)

Xiang Dingcheng; Yin Jilin; Gong Zhihua; Xie Zhenhong; Zhang Jinhe; Wen Yanfei; Yi Shaodong

2010-01-01

Objective: To investigate the mechanism of reverse redistribution (RR) on dipyridamole 201 Tl myocardial perfusion studies in the patients with coronary artery spasm. Methods: Twenty-six patients with coronary artery spasm and presented as RR on dipyridamole 201 Tl myocardial perfusion studies were enlisted as RR group, while other 16 patients with no coronary artery stenosis nor RR were enlisted as control group. Dipyridamole test was repeated during coronary angiography. Corrected thrombolysis in myocardial infarction (TIMI) frame count (CTFC) and TIMI myocardial perfusion grade (TMPG) were measured at RR related and non-RR related coronary arteries before and after dipyridamole infusion respectively. All of the data were analyzed by Student's t-test or χ 2 -test and correlation analysis. Results: Coronary artery angiography showed slower blood flow and lower myocardial perfusion in RR related vessels when compared with non-RR related vessels in RR group, but there was no significant difference among the main coronary arteries in control group. The perfusion defects of RR area at rest were positively related to slower blood velocity at corresponding coronary arteries (r = 0.79, t =10.18, P 0.05). Conclusion: RR is related to the decreased blood flow and myocardial perfusion induced by coronary artery spasm at rest, which may be improved by stress test such as intravenous dipyridamole infusion. (authors)

Clinical evaluation of iterative reconstruction (ordered-subset expectation maximization) in dynamic positron emission tomography: quantitative effects on kinetic modeling with N-13 ammonia in healthy subjects

DEFF Research Database (Denmark)

Hove, Jens Dahlgaard; Rasmussen, R.; Freiberg, J.

2008-01-01

emission tomography (PET) studies from 20 normal volunteers at rest and during dipyridamole stimulation were analyzed. Image data were reconstructed with either FBP or OSEM. FBP- and OSEM-derived input functions and tissue curves were compared together with the myocardial blood flow and spillover values...... and OSEM flow values were observed with a flow underestimation of 45% (rest/dipyridamole) in the septum and of 5% (rest) and 15% (dipyridamole) in the lateral myocardial wall. CONCLUSIONS: OSEM reconstruction of myocardial perfusion images with N-13 ammonia and PET produces high-quality images for visual...... interpretation. However, compared with FBP, OSEM is associated with substantial underestimation of perfusion on quantitative imaging. Our findings indicate that OSEM should be used with precaution in clinical PET studies Udgivelsesdato: 2008/7...

Clinical evaluation of iterative reconstruction (ordered-subset expectation maximization) in dynamic positron emission tomography: quantitative effects on kinetic modeling with N-13 ammonia in healthy subjects

DEFF Research Database (Denmark)

Hove, Jens D; Rasmussen, Rune; Freiberg, Jacob

2008-01-01

BACKGROUND: The purpose of this study was to investigate the quantitative properties of ordered-subset expectation maximization (OSEM) on kinetic modeling with nitrogen 13 ammonia compared with filtered backprojection (FBP) in healthy subjects. METHODS AND RESULTS: Cardiac N-13 ammonia positron...... emission tomography (PET) studies from 20 normal volunteers at rest and during dipyridamole stimulation were analyzed. Image data were reconstructed with either FBP or OSEM. FBP- and OSEM-derived input functions and tissue curves were compared together with the myocardial blood flow and spillover values...... and OSEM flow values were observed with a flow underestimation of 45% (rest/dipyridamole) in the septum and of 5% (rest) and 15% (dipyridamole) in the lateral myocardial wall. CONCLUSIONS: OSEM reconstruction of myocardial perfusion images with N-13 ammonia and PET produces high-quality images for visual...

Evaluation of coronary blood flow reserve by 13N-NH3 positron emission computed tomography (PET) with dipyridamole in the treatment of hypertension with the ACE inhibitor (Cilazapril)

International Nuclear Information System (INIS)

Masuda, Daisuke; Nohara, Ryuji; Tamaki, Nagara

2000-01-01

The purpose of this study was to evaluate the effect of treatment with an angiotensin-converting enzyme (ACE) inhibitor (Cilazapril) for early hypertensive patients in terms of coronary blood flow reserve evaluated by 13 NH 3 -positron emission tomography (PET). Before and after 12 weeks of ACE inhibitor treatment, 13 NH 3 -PET with dipyridamole provocation test was performed, and definite myocardial perfusion and coronary flow reserve (CFR) were calculated. Compared to our normal subjects previously reported (2.61±0.74), average coronary flow reserve was decreased (1.70±0.64 in hypertensive patients), and improved after treatment (1.77±0.52), but not significantly. Of 12 patients, five (42%) showed improved coronary flow reserve from 1.34 to 1.99 without a significant change in the resting flow. Only one patient (8%) showed deterioration after the ACE inhibitor treatment. The coronary vascular resistance (CVR) after ACE inhibitor treatment of the patients with CFR <2.0 decreased significantly compared with those with CFR ≥2.0 (p<0.03). These results indicate that hypertensive patients at the early stage show decreased coronary flow reserve despite having normal resting flow. Treatment with an ACE inhibitor (Cilazapril) for 12 weeks improved coronary flow reserve in 42% of our patients. The CVR of the patients with CFR <2.0 showed improvement compared to those with CFR ≥2.0. This result indicates that an ACE inhibitor (e.g., Cilazapril) should be one of the choices for improving CFR if hypertensive patients in early stage show signs of ischemia or diastolic dysfunction, which may be one of the sequels of reserve restriction. (author)

Antiplatelet therapy for recurrent stroke prevention: newer perspectives based on (MATCH), (CHARISMA), and (ESPRIT).

Science.gov (United States)

Gorelick, Philip B

2008-01-01

Antiplatelet therapy is an important component of our armamentarium for recurrent stroke prevention. Aspirin is a safe and effective antiplatelet drug for recurrent stroke prevention, however, it has been challenged recently by the thienopyridine derivative, clopidogrel, and the combination agent, aspirin plus extended release dipyridamole. In this review, we discuss recent studies of thienopyridine derivatives and aspirin plus extended-release dipyridamole in stroke prevention and evidence-based guidelines for the administration of these agents in practice for recurrent stroke prevention.

Dipyridamole stress myocardial perfusion by computed tomography in patients with left bundle branch block; Perfusao miocardica de estresse com dipiridamol por tomografia computadorizada em pacientes com bloqueio de ramo esquerdo

Energy Technology Data Exchange (ETDEWEB)

Cabeda, Estevan Vieira; Rochitte, Carlos Eduardo; Nomura, Cesar Higa; Parga, Jose Rodrigues; Avila, Luiz Francisco Rodrigues; Falcao, Andrea Maria Gomes; Soares Junior, Jose [Instituto do Coracao (InCor), Universidade de Sao Paulo (USP), Sao Paulo, SP (Brazil)

2015-12-15

Background: Functional tests have limited accuracy for identifying myocardial ischemia in patients with left bundle branch block (LBBB). Objective: To assess the diagnostic accuracy of dipyridamole-stress myocardial computed tomography perfusion (CTP) by 320-detector CT in patients with LBBB using invasive quantitative coronary angiography (QCA) (stenosis ≥ 70%) as reference; to investigate the advantage of adding CTP to coronary computed tomography angiography (CTA) and compare the results with those of single photon emission computed tomography (SPECT) myocardial perfusion scintigraphy. Methods: Thirty patients with LBBB who had undergone SPECT for the investigation of coronary artery disease were referred for stress tomography. Independent examiners performed per-patient and per-coronary territory assessments. All patients gave written informed consent to participate in the study that was approved by the institution's ethics committee. Results: The patients' mean age was 62 ± 10 years. The mean dose of radiation for the tomography protocol was 9.3 ± 4.6 mSv. With regard to CTP, the per-patient values for sensitivity, specificity, positive and negative predictive values, and accuracy were 86%, 81%, 80%, 87%, and 83%, respectively (p = 0.001). The per-territory values were 63%, 86%, 65%, 84%, and 79%, respectively (p < 0.001). In both analyses, the addition of CTP to CTA achieved higher diagnostic accuracy for detecting myocardial ischemia than SPECT (p < 0.001). Conclusion: The use of the stress tomography protocol is feasible and has good diagnostic accuracy for assessing myocardial ischemia in patients with LBBB. (author)

Prediction of improvement of myocardial wall motion after coronary artery bypass surgery using rest Tl-201/dipyridamole stress gated Tc-99m-MIBI/24 hour delay Tl-201 SPECT

International Nuclear Information System (INIS)

Lee, Dong Soo; Lee, Won Woo; Yeo, Jeong Yeo; Kim, Seok Ki; Kim, Ki Bong; Chung, June Key; Lee, Myung Chul

1998-01-01

Using rest Tl-201/ dipyridamole stress gated Tc-99m-MIBI/24 hour delay Tl-201 SPECT, we investigated the predictive values of the markers of the stress-rest reversibility (Rev), Tl-201 rest perfusion (Rest), Tl-201 24 hour redistribution (Del) and Tc-99m-MIBI gated systolic thickening (Thk) for wall motion improvement after coronary artery bypass surgery. In 39 patients (M:F=34:5, age 58±8), preoperative and postoperative (3 months) SPECT were compared. 24 hour delayed SPECT was done in 16 patients having perfusion defects at rest. Perfusion or wall motion was scored from 0 to 3 (0: normal to 3: defect or dyskinesia). Wall motion was abnormal in 142 segments among 585 segments of 99 artery territories which were surgically revascularized. After bypass surgery, ejection fraction increased from 37.8±9.0% to 45.5±12.3% in 22 patients who had decreased ejectin fraction preoperatively. Wall motion improved in 103 (72.5%) segments among 142 dysfunctional segments. Positive predictive values (PPV) of Rev, Rest, Del, and Thk were 83%, 76%, 43%, and 69% respectively. Negative predictive values (NPV) of Rev, Rest, Del, and Thk were 48%, 44%, 58%, and 21%, respectively. Rest/gated stress/delay SPECT had PPV of 74% and NPV of 46%. Through univariate logistic regression analysis revealed Rev( p=0.0008) and Rest (p=0.024) as significant predictors, stepwise multivariate test found Rev as the only good predictor (p=0.0008). Among independent predictors obtained by rest Tl-201/stress gated Tc-99m-MIBI/delayed Tl-201 myocardial SPECT for wall motion improvement after bypass surgery, stress-rest reversibility was the single most useful predictor

Effect of {beta}{sub 1} adrenergic receptor blockade on myocardial blood flow and vasodilatory capacity

Energy Technology Data Exchange (ETDEWEB)

Boettcher, M.; Czernin, J.; Sun, K. [Univ. of California, Los Angeles, CA (United States)] [and others

1997-03-01

The {beta}{sub 1} receptor blockade reduces cardiac work and may thereby lower myocardial blood flow (MBF) at rest. The effect of {beta}{sub 1} receptor blockade on hyperemic MBF is unknown. To evaluate the effect of selective {beta}{sub 1} receptor blockade on MBF at rest and during dipyridamole induced hyperemia, 10 healthy volunteers (8 men, 2 women, mean age 24 {+-} 5 yr) were studied using {sup 13}N-ammonia PET (two-compartment model) under control conditions and again during metoprolol (50 mg orally 12 hr and 1 hr before the study). The resting rate pressure product (6628 {+-} 504 versus 5225 {+-} 807) and heart rate (63 {+-} 6-54 {plus_minus} 5 bpm) declined during metoprolol (p < 0.05). Similarly, heart rate and rate pressure product declined from the baseline dipyridamole study to dipyridamole plus metoprolol (p < 0.05). Resting MBF declined in proportion to cardiac work by approximately 20% from 0.61 {+-} 0.09-0.51 {+-} 0.10 ml/g/min (p < 0.05). In contrast, hyperemic MBF increased when metoprolol was added to dipyridamole (1.86 {plus_minus} 0.27 {+-} 0.45 ml/g/min; p<0.05). The decrease in resting MBF together with the increase in hyperemic MBF resulted in a significant increase in the myocardial flow reserve during metoprolol (3.14 {+-} 0.80-4.61 {+-} 0.68; p<0.01). The {beta}{sub 1} receptor blockade increases coronary vasodilatory capacity and myocardial flow reserve. However, the mechanisms accounting for this finding remain uncertain. 32 refs., 2 figs., 2 tabs.

Reduced coronary flow and resistance reserve in primary scleroderma myocardial disease

International Nuclear Information System (INIS)

Nitenberg, A.; Foult, J.M.; Kahan, A.; Perennec, J.; Devaux, J.Y.; Menkes, C.J.; Amor, B.

1986-01-01

The maximum coronary vasodilator capacity after intravenous dipyridamole (0.14 mg X kg-1 X min-1 X 4 minutes) was studied in seven patients with primary scleroderma myocardial disease and compared to that of seven control subjects. Hemodynamic data and left ventricular angiographic data were not different in the two groups. The coronary flow reserve was evaluated by the dipyridamole/basal coronary sinus blood flow ratio (D/B CSBF) and the coronary resistance reserve by the dipyridamole/basal coronary resistance ratio (D/B CR). Coronary reserve was greatly impaired in the group with primary scleroderma myocardial disease: D/B CSBF was lower than in the control group (2.54 +/- 1.37 vs 4.01 +/- 0.56, respectively; p less than 0.05) and D/B CR was higher than in the control group (0.47 +/- 0.25 vs 0.23 +/- 0.04, respectively; p less than 0.05). Such a decreased coronary flow and resistance reserve in patients with primary scleroderma myocardial disease was not explained by an alteration of left ventricular function. It may be an important contributing factor in the pathogenesis of primary scleroderma myocardial disease

Reduction of myocardial blood flow reserve in idiopathic dilated cardiomyopathy without overt heart failure and its relation with functional indices: an echo-Doppler and positron emission tomography study.

Science.gov (United States)

Morales, Maria-Aurora; Neglia, Danilo; L'Abbate, Antonio

2008-08-01

Myocardial blood flow during pharmacological vasodilatation is depressed in patients with idiopathic dilated cardiomyopathy even the in absence of overt heart failure; the extent of myocardial blood flow abnormalities is not predictable by left ventricular ejection fraction (LVEF) and diastolic dimensions. To assess whether myocardial blood flow impairment in idiopathic dilated cardiomyopathy without overt heart failure can be related to Doppler-derived dP/dt and to echocardiographically determined left ventricular end systolic stress - which is linked to myocardial blood flow reserve in advanced disease. Twenty-six patients, New York Heart Association Class I-II, (LVEF 37.4 +/- 1.4%, left ventricular diastolic dimensions 62.6 +/- 0.9 mm) underwent resting/dipyridamole [13N]NH3 flow positron emission tomography and an ultrasonic study. Regional myocardial blood flow values (ml/min per g) were computed from positron emission tomography data in 13 left ventricular (LV) myocardial regions and averaged to provide mean myocardial blood flow and myocardial blood flow reserve, defined as dipyridamole/resting mean myocardial blood flow ratio. Resting myocardial blood flow was 0.686 +/- 0.045, dipyridamole myocardial blood flow 1.39 +/- 0.15 and myocardial blood flow reserve 2.12 +/- 0.2, lower than in controls (P < 0.01). The ratio dP/dt was directly related to dipyridamole myocardial blood flow and myocardial blood flow reserve (r = 0.552 and 0.703, P < 0.005 and P < 0.0001); no relation was found between myocardial blood flow and LVEF left ventricular diastolic dimensions, and left ventricular end systolic stress. In idiopathic dilated cardiomyopathy patients without overt heart failure, the extent of myocardial blood flow reserve impairment is related to dP/dt but not to more classical indices of left ventricular function.

Longitudinal assessment of thrombin generation potential in response to alteration of antiplatelet therapy after TIA or ischaemic stroke.

LENUS (Irish Health Repository)

Tobin, W O

2013-02-01

The impact of changing antiplatelet therapy on thrombin generation potential in patients with ischaemic cerebrovascular disease (CVD) is unclear. We assessed patients within 4 weeks of TIA or ischaemic stroke (baseline), and then 14 days (14d) and >90 days (90d) after altering antiplatelet therapy. Thrombin generation was assessed in platelet poor plasma. Ninety-one patients were recruited. Twenty-four were initially assessed on no antiplatelet therapy, and then after 14d (N = 23) and 90d (N = 8) on aspirin monotherapy; 52 were assessed on aspirin monotherapy, and after 14 and 90 days on aspirin and dipyridamole combination therapy; 21 patients were assessed on aspirin and after 14 days (N = 21) and 90 days (N = 19) on clopidogrel. Peak thrombin generation and endogenous thrombin potential were reduced at 14 and 90 days (p ≤ 0.04) in the overall cohort. We assessed the impact of individual antiplatelet regimens on thrombin generation parameters to investigate the cause of this effect. Lag time and time-to-peak thrombin generation were unchanged at 14 days, but reduced 90 days after commencing aspirin (p ≤ 0.009). Lag time, peak thrombin generation and endogenous thrombin potential were reduced at both 14 and 90 days after adding dipyridamole to aspirin (p ≤ 0.01). Lag time was reduced 14 days after changing from aspirin to clopidogrel (p = 0.045), but this effect was not maintained at 90 days (p = 0.2). This pilot study did not show any consistent effects of commencing aspirin, or of changing from aspirin to clopidogrel on thrombin generation potential during follow-up. The addition of dipyridamole to aspirin led to a persistent reduction in peak and total thrombin generation ex vivo, and illustrates the diverse, potentially beneficial, newly recognised \\'anti-coagulant\\' effects of dipyridamole in ischaemic CVD.

New developments in secondary stroke prevention: impact of the European/Australasian Stroke Prevention in Reversible Ischemia Trial (ESPRIT) on clinical management.

Science.gov (United States)

Lutsep, Helmi L

2007-01-01

Secondary stroke prevention is an important goal of poststroke patient treatment. Various pharmacologic approaches have been advocated, but the relative efficacy and safety of these regimens has remained the subject of much debate. Recently released data from the European/Australasian Stroke Prevention in Reversible Ischemia Trial (ESPRIT) indicated that combination therapy with aspirin and extended-release dipyridamole was more effective than aspirin monotherapy, and probably more effective than anticoagulants, for the prevention of cerebrovascular events after a stroke or transient ischemic attack. When viewed in light of results of earlier trials, these findings confirmed that combination aspirin plus extended-release dipyridamole therapy improved outcomes in these patients and is a recommended option for poststroke patient treatment.

Aspirin and Extended-Release Dipyridamole

Science.gov (United States)

... Mobic), nabumetone (Relafen), naproxen (Aleve, Naprosyn), oxaprozin (Daypro), piroxicam (Feldene), rofecoxib (Vioxx) (no longer available in the ... Mobic), nabumetone (Relafen), naproxen (Aleve, Naprosyn), oxaprozin (Daypro), piroxicam (Feldene), sulindac (Clinoril), and tolmetin (Tolectin); phenytoin (Dilantin); ...

Metabolic intervention in surgical patients. An assessment of the effect of somatostatin, ranitidine, naloxone, diclophenac, dipyridamole, or salbutamol infusion on energy and protein kinetics in surgical patients using stable and radioisotopes

International Nuclear Information System (INIS)

Shaw, J.H.; Wolfe, R.R.

1988-01-01

We have assessed the effect of a variety of forms of metabolic intervention on both energy and protein metabolism in 44 severely ill surgical patients. The patients were studied either in the basal state or while receiving total parenteral nutrition (TPN), and the metabolic effects were assessed using the primed-constant infusion of a combination of stable isotopes and radioisotopes. Somatostatin infusion, either in the basal state or in the TPN, did not change glucose kinetics, but there was a significant decrease in the rate of net protein catabolism (NPC). In the basal studies the rate of NPC decreased from 3.4 +/- 0.7 g/kg/d to 2.9 +/- 0.7 g/kg/d (p less than 0.002), while in the TPN patients the corresponding values were 1.48 +/- 0.61 g/kg/d and 1.10 +/- 0.50 g/kg/d, respectively (p less than 0.005). Histamine type 2 blockade with ranitidine did not significantly alter glucose kinetics, but in both the TPN patients and in the basal state ranitidine was associated with a significant decrease in the rate of NPC. In the basal state rate of NPC was 2.44 +/- 0.53 g/kg/d and during ranitidine infusion the value was 2.08 +/- 0.42 g/kg/d (p less than 0.04). Naloxone infusion did not alter glucose kinetics, but there was a significant decrease in the rate of NPC from a basal value of 2.6 +/- 0.6 g/kg/d to 2.3 +/- 0.5 g/kg/d (p less than 0.04). The infusion of the prostaglandin antagonists diclofenac or dipyridamole resulted in increases in the plasma insulin level, and as a result glucose turnover decreased in both groups. In the diclofenac group the rate of glucose turnover decreased from 14.4 +/- 1.7 mumol/kg/min to 12.6 +/- 1.3 mumol/kg/min (p less than 0.02). Neither prostaglandin antagonist resulted in any significant change in the rate of NPC

The role of cGMP hydrolysing phosphodiesterases 1 and 5 in cerebral artery dilatation

DEFF Research Database (Denmark)

Kruuse, Christina; Rybalkin, S D; Khurana, T S

2001-01-01

The aim was to investigate the presence and activity of cGMP hydrolysing phosphodiesterases in guinea pig basilar arteries and the effect of selective and non-selective phosphodiesterase inhibitors on cerebral artery dilatation involving the nitric oxide (NO)-guanosine cyclic 3'5-monophosphate (cGMP...... a close relation to the nitric oxide-cGMP pathway. The responses to zaprinast and dipyridamole, however, were not only moderately affected, but also restored by sodium nitroprusside (0.1 microM) pretreatment. At high concentrations, the dilatory effects of zaprinast and dipyridamole were partly caused...... by cGMP-independent mechanisms. Targeting the phosphodiesterases present in cerebral arteries, with selective inhibitors or activators of phosphodiesterase, may be a possible new way of treating cerebrovascular disease....

Myocardial Blood Volume Is Associated with Myocardial Oxygen Consumption: An Experimental Study with CMR in a Canine Model

Science.gov (United States)

McCommis, Kyle S.; Zhang, Haosen; Goldstein, Thomas A.; Misselwitz, Bernd; Abendschein, Dana R.; Gropler, Robert J.; Zheng, Jie

2009-01-01

OBJECTIVES To evaluate the feasibility of cardiovascular MR (CMR) to determine regional myocardial perfusion and O2 metabolism, and assess the role of myocardial blood volume (MBV) on oxygen supply. BACKGROUND Coronary artery disease presents as an imbalance of myocardial oxygen supply and demand. We have developed relevant CMR methods to determine the relationship of myocardial blood flow (MBF) and MBV to oxygen consumption (MVO2) during pharmacologic hyperemia. METHODS Twenty-one mongrel dogs were studied with varying stenosis severities imposed on the proximal left anterior descending (LAD) coronary artery. MBF and MBV were determined by CMR first-pass perfusion, while the oxygen extraction fraction (OEF) and MVO2 were determined by the myocardial Blood-Oxygen-Level-Dependent (BOLD) effect and Fick’s law, respectively. MR imaging was performed at rest, and during either dipyridamole-induced vasodilation or dobutamine-induced hyperemia. Regional differences in myocardial perfusion and oxygenation were then evaluated. RESULTS Dipyridamole and dobutamine both led to 145–200% increases in MBF and 50–80% increases in MBV in normal perfused myocardium. As expected, MVO2 increased more significantly with dobutamine (~175%) than dipyridamole (~40%). Coronary stenosis resulted in an attenuation of MBF, MBV, and MVO2 in both the LAD-subtended stenosis region and the left circumflex subtended remote region. Liner regression analysis showed that MBV reserve appears to be more correlated with MVO2 reserve during dobutamine stress than MBF reserve, particularly in the stenotic regions. Conversely, MBF reserve appears to be more correlated with MVO2 reserve during dipyridamole, although neither of these differences was significant. CONCLUSIONS Noninvasive evaluation of both myocardial perfusion and oxygenation by CMR facilitates direct monitoring of regional myocardial ischemia and provides a valuable tool for better understanding microvascular pathophysiology. These

Respiratory gating in cardiac PET

DEFF Research Database (Denmark)

Lassen, Martin Lyngby; Rasmussen, Thomas; Christensen, Thomas E

2017-01-01

BACKGROUND: Respiratory motion due to breathing during cardiac positron emission tomography (PET) results in spatial blurring and erroneous tracer quantification. Respiratory gating might represent a solution by dividing the PET coincidence dataset into smaller respiratory phase subsets. The aim...... of our study was to compare the resulting imaging quality by the use of a time-based respiratory gating system in two groups administered either adenosine or dipyridamole as the pharmacological stress agent. METHODS AND RESULTS: Forty-eight patients were randomized to adenosine or dipyridamole cardiac...... stress (82)RB-PET. Respiratory rates and depths were measured by a respiratory gating system in addition to registering actual respiratory rates. Patients undergoing adenosine stress showed a decrease in measured respiratory rate from initial to later scan phase measurements [12.4 (±5.7) vs 5.6 (±4...

Comparison of antiplatelet regimens in secondary stroke prevention

DEFF Research Database (Denmark)

Christiansen, Christine Benn; Pallisgaard, Jannik; Gerds, Thomas Alexander

2015-01-01

BACKGROUND: In patients with ischemic stroke of non-cardioembolic origin, acetylsalicylic acid, clopidogrel, or a combination of acetylsalicylic acid and dipyridamole are recommended for the prevention of a recurrent stroke. The purpose of this study was to examine the risk of bleeding or recurrent...... stroke associated with these three treatments. METHODS: Patients who were discharged with first-time ischemic stroke from 2007-2010, with no history of atrial fibrillation were identified from Danish nationwide registries. Hazard ratios (HRs) and 1-year risks of recurrent ischemic stroke and bleeding...... were calculated for each antiplatelet regimen. RESULTS: Among patients discharged after first-time ischemic stroke, 3043 patients were treated with acetylsalicylic acid, 12,295 with a combination of acetylsalicylic acid and dipyridamole, and 3885 with clopidogrel. Adjusted HRs for clopidogrel versus...

Noninvasive Diagnostic Technique in Stenotic Coronary Atherosclerosis

Directory of Open Access Journals (Sweden)

A. Yu. Vasilyev

2005-01-01

Full Text Available Objective: to determine the sensitivity and specificity of combined stress echocardiography (EchoCG using dipyri-damole and dobutamine in diagnosing and defining the extent of stenotic coronary lesions in coronary heart disease (CHD in a group of critically ill patients who are unable to perform a physical exercise.Materials and methods: the study included 57 male patients with suspected acute coronary syndrome who underwent stress EchoCG using dipyridamole in high doses in combination with dobutamine, as well as coronary angiography.Results: stress EchoCG could bring up to the diagnostic criteria in all the patients, of whom 9 patients were found at coronary angiography to have no coronary lesion, 34 and 14 patients had one- and many-vessel lesions, respectively. The sensitivity and specificity of combined stress EchoCG were significantly higher than those of EchoCG used in the diagnosis of CHD.Conclusion: stress EchoCG using dipyridamole in combination with dobutamine is a highly informative safe noninvasive technique for diagnosing CHD, its helps to identify patients with atypical acute coronary syndrome and to form a group of patients to be subject to urgent coronarography and angiosurgical intervention. The pattern of segmental contractile disorders at the height of exercise during combined stress Echo-CG makes it possible to define the site of stenotic coronary atherosclerosis with 97.3% sensitivity and to diagnose many-vessel lesion with 100% sensitivity and 100%specificity.

Technetium-99m sestamibi single-photon emission tomography detects subclinical myocardial perfusion abnormalities in patients with systemic lupus erythematosus

Energy Technology Data Exchange (ETDEWEB)

Schillaci, O. [Nuclear Medicine, University of l`Aquila (Italy); Lagana, B.; Gentile, R.; Tubani, L.; Baratta, L. [Department of Clinical Medicine, University ``La Sapienza``, Rome (Italy); Danieli, R.; Scopinaro, F. [Section of Nuclear Medicine, Department of Experimental Medicine and Pathology, University ``La Sapienza``, Rome (Italy)

1999-07-01

In patients with systemic lupus erythematosus, involvement of the cardiovascular system is the third leading cause of death. However, although autopsy studies have demonstrated a high incidence of abnormalities in both the myocardium and coronary vessels, clinical manifestations have been reported in only a small percentage of cases. The aim of this study was to evaluate myocardial perfusion in asymptomatic lupus patients using technetium-99m sestamibi single-photon emission tomography (SPET). Twenty-eight patients without overt cardiac involvement and risk factors were studied with {sup 99m}Tc-sestamibi SPET at rest and after dipyridamole infusion. Perfusion abnormalities were detected in 18 cases: six had persistent defects, three had reversible defects, seven had both persistent and reversible defects, and two showed rest defects which normalized on dipyridamole images (``reverse redistribution pattern``). Coronary angiography was performed in eight patients with positive {sup 99m}Tc-sestamibi SPET, and showed normal epicardial vessels in all the cases. These results indicate that {sup 99m}Tc-sestamibi SPET reveals a high prevalence (18 out of 28 patients in this study, i.e. 64%) of myocardial perfusion abnormalities in asymptomatic lupus patients, probably due to the primary immunological damage of this autoimmune disease. In conclusion, rest/dipyridamole {sup 99m}Tc-sestamibi SPET can be a useful non-invasive method to identify subclinical myocardial involvement in systemic lupus erythematosus, and patients potentially at risk of later cardiac events. (orig.) With 2 figs., 2 tabs., 21 refs.

Turnover of adenosine in plasma of human and dog blood

International Nuclear Information System (INIS)

Moeser, G.H.S.; Schrader, J.; Deussen, A.

1989-01-01

To determine half-life and turnover of plasma adenosine, heparinized blood from healthy volunteers was incubated with radiolabeled adenosine in the physiological concentration range of 0.1-1 microM. Plasma levels of adenosine in vitro were 82 +/- 14 nM and were similar to those determined immediately after blood collection with a ''stopping solution.'' Dipyridamole (83 microM) and erythro-9(2-hydroxynon-3yl)-adenine (EHNA) (8 microM) did not measurably alter basal adenosine levels but completely blocked the uptake of added adenosine. Inhibition of ecto-5'-nucleotidase with 100 microM alpha, beta-methyleneadenosine 5'-diphosphate (AOPCP) reduced plasma adenosine to 22 +/- 6 nM. For the determination of adenosine turnover, the decrease in specific radioactivity of added [ 3 H]adenosine was measured using a dipyridamole-containing stopping solution. Without altering basal adenosine levels, the half-life was estimated to be 0.6 s. Similar experiments were carried out with washed erythrocytes or in the presence of AOPCP, yielding half-lives of 0.7 and 0.9 s, respectively. When the initial adenosine concentration was 1 microM, its specific activity decreased by only 11% within 5 s, whereas total plasma adenosine exponentially decreased with a half-life of 1.5 s. Venous plasma concentrations were measured after relief of a 3-min forearm ischemia. Changes in plasma adenosine did not correlate well with changes in blood flow but were augmented in the presence of dipyridamole

Effect of streptozotocin-induced diabetes on myocardial blood flow reserve assessed by myocardial contrast echocardiography in rats

Directory of Open Access Journals (Sweden)

Weytjens Caroline

2008-09-01

Full Text Available Abstract The role of structural and functional abnormalities of small vessels in diabetes cardiomyopathy remains unclear. Myocardial contrast echocardiography allows the quantification of myocardial blood flow at rest and during dipyridamole infusion. The aim of the study was to determine the myocardial blood flow reserve in normal rats compared with Streptozotocin-induced diabetic rats using contrast echocardiography. Methods We prospectively studied 40 Wistar rats. Diabetes was induced by intravenous streptozotocin in 20 rats. All rats underwent baseline and stress (dipyridamole: 20 mg/kg high power intermittent imaging in short axis view under anaesthesia baseline and after six months. Myocardial blood flow was determined and compared at rest and after dipyridamole in both populations. The myocardial blood flow reserve was calculated and compared in the 2 groups. Parameters of left ventricular function were determined from the M-mode tracings and histological examination was performed in all rats at the end of the study. Results At six months, myocardial blood flow reserve was significantly lower in diabetic rats compared to controls (3.09 ± 0.98 vs. 1.28 ± 0.67 ml min-1 g-1; p Conclusion In this animal study, diabetes induced a functional alteration of the coronary microcirculation, as demonstrated by contrast echocardiography, a decrease in capillary density and of the cardiac systolic function. These findings may offer new insights into the underlying mechanisms of diabetes cardiomyopathy.

Technetium-99m sestamibi single-photon emission tomography detects subclinical myocardial perfusion abnormalities in patients with systemic lupus erythematosus

International Nuclear Information System (INIS)

Schillaci, O.; Lagana, B.; Gentile, R.; Tubani, L.; Baratta, L.; Danieli, R.; Scopinaro, F.

1999-01-01

In patients with systemic lupus erythematosus, involvement of the cardiovascular system is the third leading cause of death. However, although autopsy studies have demonstrated a high incidence of abnormalities in both the myocardium and coronary vessels, clinical manifestations have been reported in only a small percentage of cases. The aim of this study was to evaluate myocardial perfusion in asymptomatic lupus patients using technetium-99m sestamibi single-photon emission tomography (SPET). Twenty-eight patients without overt cardiac involvement and risk factors were studied with 99m Tc-sestamibi SPET at rest and after dipyridamole infusion. Perfusion abnormalities were detected in 18 cases: six had persistent defects, three had reversible defects, seven had both persistent and reversible defects, and two showed rest defects which normalized on dipyridamole images (''reverse redistribution pattern''). Coronary angiography was performed in eight patients with positive 99m Tc-sestamibi SPET, and showed normal epicardial vessels in all the cases. These results indicate that 99m Tc-sestamibi SPET reveals a high prevalence (18 out of 28 patients in this study, i.e. 64%) of myocardial perfusion abnormalities in asymptomatic lupus patients, probably due to the primary immunological damage of this autoimmune disease. In conclusion, rest/dipyridamole 99m Tc-sestamibi SPET can be a useful non-invasive method to identify subclinical myocardial involvement in systemic lupus erythematosus, and patients potentially at risk of later cardiac events. (orig.)

Reproducibility of quantitative planar thallium-201 scintigraphy: quantitative criteria for reversibility of myocardial perfusion defects

International Nuclear Information System (INIS)

Sigal, S.L.; Soufer, R.; Fetterman, R.C.; Mattera, J.A.; Wackers, F.J.

1991-01-01

Fifty-two paired stress/delayed planar 201 TI studies (27 exercise studies, 25 dipyridamole studies) were processed twice by seven technologists to assess inter- and intraobserver variability. The reproducibility was inversely related to the size of 201 Tl perfusion abnormalities. Intraobserver variability was not different between exercise and dipyridamole studies for lesions of similar size. Based upon intraobserver variability, objective quantitative criteria for reversibility of perfusion abnormalities were defined. These objective criteria were tested prospectively in a separate group of 35 201 Tl studies and compared with the subjective interpretation of quantitative circumferential profiles. Overall, exact agreement existed in 78% of images (kappa statistic k = 0.66). We conclude that quantification of planar 201 Tl scans is highly reproducible, with acceptable inter- and intraobserver variability. Objective criteria for lesion reversibility correlated well with analysis by experienced observers

Update on antiplatelet agents, including MATCH, CHARISMA, and ESPRIT.

Science.gov (United States)

Skliut, Maryna; Jamieson, Dara G

2008-02-01

Despite recent advances in the acute treatment of stroke, prevention and risk factor modification remain the mainstays of management for patients with ischemic stroke and transient ischemic attack. The majority of noncardioembolic ischemic strokes are atherothrombotic, presumed to be associated with the activation and aggregation of platelets. Antiplatelet medications have been shown to be effective in the secondary prevention of stroke of presumed arterial origin, both as monotherapy and in combination. Among combination of antiplatelet agents, aspirin plus extended-release dipyridamole has demonstrated statistically significant additive benefit over monotherapy with each agent. Clopidogrel plus aspirin does not prevent recurrent ischemic stroke over each component individually, and the combination increases the risk of hemorrhagic side effects. This article reviews the most recent studies on antiplatelet medications, including the combination of aspirin and clopidogrel or extended-release dipyridamole, and discusses some of the controversies that still exist with the use of antiplatelet agents.

Tomographic myocardial perfusion scintigraphy in children with Kawasaki disease

International Nuclear Information System (INIS)

Spielmann, R.P.; Nienaber, C.A.; Hausdorf, G.; Montz, R.

1987-01-01

Myocardial infarction and stenotic coronary lesions are serious late complications in children with Kawasaki disease. For the noninvasive assessment of myocardial perfusion, dipyridamole-redistribution 201 Tl emission computed tomography (ECT) was performed in seven children (age 2 8/12-8 7/12 yr) 3-20 mo after the acute stage of the disease. In all patients, coronary aneurysms had been demonstrated by cross-sectional echocardiography. The scintigrams of six children showed no significant regional reduction of myocardial thallium uptake. These children had remained asymptomatic since the acute stage of Kawasaki disease. Persistent and transient thallium defects were present in one child with documented myocardial infarction. For this patient, obstruction of corresponding coronary vessels was confirmed by contrast angiography. It is suggested, that 201 Tl ECT after dipyridamole-induced vasodilation may be used as a safe alternative to invasive coronary angiography for follow-up investigations in patients with Kawasaki disease

Effects of antithrombotic drugs in patients with left ventricular thrombi: assessment with indium-111 platelet imaging and two-dimensional echocardiography

International Nuclear Information System (INIS)

Stratton, J.R.; Ritchie, J.L.

1984-01-01

Patients with left ventricular thrombi not caused by recent myocardial infarction were prospectively studied by indium-111 platelet imaging and two-dimensional echocardiography to determine the reproducibility of these techniques and the short-term effects of sulfinpyrazone (200 mg four times daily), aspirin (325 mg three times daily) plus dipyridamole (75 mg three times daily), and full-dose warfarin. At baseline, all patients underwent indium-111 platelet imaging and echocardiography, and the results were positive for thrombus. In six patients on no antithrombotic drug therapy, repeat platelet scans and echocardiographic studies at 6.0 +/- 3.3 weeks remained positive and were unchanged. In seven patients studied on sulfinpyrazone, three platelet scans became negative, two became equivocal, and two were unchanged; the presence and size of thrombus was constant by echocardiography in all seven patients. Of the six patients studied on aspirin plus dipyridamole, one platelet scan became negative, those of three became equivocal, and two were unchanged; all echocardiographic findings remained positive, but one patient had decreased thrombus size. Among four warfarin-treated patients, three had resolution of platelet deposition and one was unchanged; by echocardiography, thrombus resolved in one patient, was decreased in size in one, and was unchanged in two. We conclude that, in the absence of antithrombotic drug therapy, platelet imaging and echocardiographic findings are stable in patients with left ventricular thrombi not caused by recent myocardial infarction. Sulfinpyrazone, aspirin plus dipyridamole, and warfarin all interrupt platelet deposition in some patients with chronic left ventricular thrombi

High fat diet-induced glucose intolerance impairs myocardial function, but not myocardial perfusion during hyperaemia: a pilot study

Directory of Open Access Journals (Sweden)

van den Brom Charissa E

2012-06-01

Full Text Available Abstract Background Glucose intolerance is a major health problem and is associated with increased risk of progression to type 2 diabetes mellitus and cardiovascular disease. However, whether glucose intolerance is related to impaired myocardial perfusion is not known. The purpose of the present study was to study the effect of diet-induced glucose intolerance on myocardial function and perfusion during baseline and pharmacological induced hyperaemia. Methods Male Wistar rats were randomly exposed to a high fat diet (HFD or control diet (CD (n = 8 per group. After 4 weeks, rats underwent an oral glucose tolerance test. Subsequently, rats underwent (contrast echocardiography to determine myocardial function and perfusion during baseline and dipyridamole-induced hyperaemia (20 mg/kg for 10 min. Results Four weeks of HFD feeding resulted in glucose intolerance compared to CD-feeding. Contractile function as represented by fractional shortening was not altered in HFD-fed rats compared to CD-fed rats under baseline conditions. However, dipyridamole increased fractional shortening in CD-fed rats, but not in HFD-fed rats. Basal myocardial perfusion, as measured by estimate of perfusion, was similar in CD- and HFD-fed rats, whereas dipyridamole increased estimate of perfusion in CD-fed rats, but not in HFD-fed rats. However, flow reserve was not different between CD- and HFD-fed rats. Conclusions Diet-induced glucose intolerance is associated with impaired myocardial function during conditions of hyperaemia, but myocardial perfusion is maintained. These findings may result in new insights into the effect of glucose intolerance on myocardial function and perfusion during hyperaemia.

CLSM as quantitative method to determine the size of drug crystals in a solid dispersion

NARCIS (Netherlands)

de Waard, Hans; Hessels, Martin J T; Boon, Maarten; Sjollema, Klaas A; Hinrichs, Wouter L J; Eissens, Anko C; Frijlink, Henderik W

2011-01-01

PURPOSE: To test whether confocal laser scanning microscopy (CLSM) can be used as an analytical tool to determine the drug crystal size in a powder mixture or a crystalline solid dispersion. METHODS: Crystals of the autofluorescent drug dipyridamole were incorporated in a matrix of crystalline

Capillary transfer constant of Gd-DTPA in the myocardium at rest and during vasodilation assessed by MRI

DEFF Research Database (Denmark)

Fritz-Hansen, T; Rostrup, Egill; Søndergaard, Lise

1998-01-01

The purpose of this study was to determine whether the capillary transfer constant (Ki) of gadolinium-DTPA was sensitive to perfusion changes and whether ischemic regions in the myocardium could be identified using the modified Kety formula. Ki was measured at rest and during dipyridamole...

Noninvasive assessment of coronary collaterals in man by PET perfusion imaging

International Nuclear Information System (INIS)

Demer, L.L.; Gould, K.L.; Goldstein, R.A.; Kirkeeide, R.L.

1990-01-01

At present, coronary collateralization cannot be identified or assessed noninvasively in patients. In animal studies, coronary collaterals are associated with coronary steal, defined as a regional fall in perfusion during coronary arteriolar vasodilation. To determine the effect of coronary arteriolar vasodilation on collateral bed perfusion in man, myocardial perfusion imaging was performed before and after pharmacologic coronary vasodilation in patients with coronary artery disease (CAD). Regional myocardial activity of 82 Rb or 13 N ammonia was measured by positron emission tomography (PET) at rest and with intravenous dipyridamole/handgrip stress in 28 patients with angiographic collaterals and in 25 control patients with similar CAD severity by quantitative arteriography. Regional myocardial activity decreased after dipyridamole, indicating coronary steal, in 25 of 28 patients with angiographic collaterals and in only 4 of 25 control patients without angiographic collaterals. These findings suggest that developed collaterals are associated with myocardial steal in patients with CAD, allowing potential use of PET for non-invasive identification of coronary collateralization

Potassium-38, a 7.6 minute half-lived radionuclide for assessment of myocardial function

International Nuclear Information System (INIS)

Chandra, R.; McDonald, J.M.; Reiman, R.E.; Tilbury, R.S.

1979-01-01

Potassium-38 in isotonic saline solution has been used to study the effect of cardio-active drugs, dipyridamole, propanolol and digoxin on the potassium uptake in the myocardium of dogs. The 38 KCl without added carrier was injected intravenously at about 0, 1, 2, and 3 hours after administration of the drug and the dog was scanned with a rectilinear scanner from 10 to 25 minutes after injection. THe counts/sec/mCi corrected for decay were computed for a fixed number of scan elements and compared with controls. Dipyridamole produced a 50 to 80% increase in potassium uptake at 1 hour which returned to normal at 3 hours, Digoxin produced a 10 to 30% increase, and propanolol produced a 25% decrease at 1 to 2 hours. Results are compared with studies of Hamilton using Tl-201. Our results demonstrate that measurements of K-38 uptake can be made at hourly intervals to study the effects of cardio-active drugs

Noninvasive radioisotopic technique for detection of platelet deposition in mitral valve prostheses and quantitation of visceral microembolism in dogs

International Nuclear Information System (INIS)

Dewanjee, M.K.; Fuster, V.; Rao, S.A.; Forshaw, P.L.; Kaye, M.P.

1983-01-01

A noninvasive technique has been developed in the dog model for imaging, with a gamma camera, the platelet deposition on Bjoerk-Shiley mitral valve prostheses early postoperatively. At 25 hours after implantation of the prosthesis and 24 hours after intravenous administration of 400 to 500 microCi of platelets labeled with indium-111, the platelet deposition in the sewing ring and perivalvular cardiac tissue can be clearly delineated in a scintiphotograph. An in vitro technique was also developed for quantitation of visceral microemboli in brain, lungs, kidneys, and other tissues. Biodistribution of the labeled platelets was quantitated, and the tissue/blood radioactivity ratio was determined in 22 dogs in four groups: unoperated normal dogs, sham-operated dogs, prosthesis-implanted dogs, and prosthesis-implanted dogs treated with dipyridamole before and aspirin and dipyridamole immediately after operation. Fifteen to 20% of total platelets were consumed as a consequence of the surgical procedure. On quantitation, we found that platelet deposition on the components of the prostheses was significantly reduced in prosthesis-implanted animals treated with dipyridamole and aspirin when compared with prosthesis-implanted, untreated dogs. All prosthesis-implanted animals considered together had a twofold to fourfold increase in tissue/blood radioactivity ratio in comparison with unoperated and sham-operated animals, an indication that the viscera work as filters and trap platelet microemboli that are presumably produced in the region of the mitral valve prostheses. In the dog model, indium-111-labeled platelets thus provide a sensitive marker for noninvasive imaging of platelet deposition on mechanical mitral valve prostheses, in vitro evaluation of platelet microembolism in viscera, in vitro quantitation of surgical consumption of platelets, and evaluation of platelet-inhibitor drugs

Syzygium cumini is more effective in preventing the increase of erythrocytic ADA activity than phenolic compounds under hyperglycemic conditions in vitro.

Science.gov (United States)

De Bona, Karine S; Bonfanti, Gabriela; Bitencourt, Paula E R; Cargnelutti, Lariane O; da Silva, Priscila S; da Silva, Thainan P; Zanette, Régis A; Pigatto, Aline S; Moretto, Maria B

2014-06-01

Syzygium cumini (S. cumini) is a plant known for its antidiabetic properties. The aim of this study was to evaluate the effect of Sc aqueous leaf extract (ASc) on adenosine deaminase (ADA) activity in erythrocytes (RBCs) exposed to high glucose concentrations (30 mM) in vitro. We also investigated the effects of the main phenolic compounds found in ASc (gallic acid, rutin, and chlorogenic acid) and the effects of insulin, caffeine, and dipyridamole, which are substances involved in the adenosine metabolism, on ADA activity in vitro. Blood samples were obtained from healthy volunteers and a suspension of RBCs was used for the determination of ADA activity. The results showed that: (1) the effect of ASc on ADA activity was more significant than the combination of phenolic compounds; (2) insulin, caffeine, or dipyridamole prevented high glucose increase of ADA activity at doses as low as 50 μU/mL, 25 μM, and 1 μM, respectively; (3) the inhibitory effect caused by ASc on erythrocyte ADA activity remained practically the same after the combination of the extract with insulin or caffeine; (4) when RBCs were exposed to ASc plus dipyridamole, this chemical attenuated the effect of ASc on ADA activity, suggesting an antagonism or a competition with ASc by the same site of action. Therefore, ASc was more effective in preventing the increase in ADA activity than phenolic compounds, suggesting that ASc may collaborate to improve endothelial dysfunction, antioxidant, anti-inflammatory, and antithrombotic properties of adenosine by affecting its metabolism. The results of this study help to provide evidence of the empirically supported benefits of the use of S. cumini in diabetes.

Assessment of coronary flow reserve by sestamibi imaging in patients with typical chest pain and normal coronary arteries

International Nuclear Information System (INIS)

Storto, Giovanni; Sorrentino, Anna R.; Pellegrino, Teresa; Liuzzi, Raffaele; Cuocolo, Alberto; Petretta, Mario

2007-01-01

We assessed coronary flow reserve (CFR) by sestamibi imaging in patients with typical chest pain, positive exercise stress test and normal coronary vessels. Thirty-five patients with typical chest pain and normal angiogram and 12 control subjects with atypical chest pain underwent dipyridamole/rest 99m Tc-sestamibi imaging. Myocardial blood flow (MBF) was estimated by measuring first transit counts in the pulmonary artery and myocardial counts from SPECT images. Estimated CFR was expressed as the ratio of stress to rest MBF. Rest MBF and CFR were corrected for rate-pressure product (RPP) and expressed as normalised MBF (MBF n ) and normalised CFR (CFR n ). Coronary vascular resistances (CVR) were calculated as the ratio between mean arterial pressure and estimated MBF. At rest, estimated MBF and MBF n were lower in controls than in patients (0.98 ± 0.4 vs 1.30 ± 0.3 counts/pixel/s and 1.14 ± 0.5 vs 1.64 ± 0.6 counts/pixel/s, respectively, both p n was still higher in controls than in patients (2.1 ± 0.5 vs 1.29 ± 0.5, p < 0.0001). At baseline, CVR values were lower (p < 0.01) in patients than in controls. Dipyridamole-induced changes in CVR were greater (p < 0.0001) in controls (-63%) than in patients (-35%). In the overall study population, a significant correlation between dipyridamole-induced changes in CVR and CFR was observed (r = -0.88, p < 0.0001). SPECT might represent a useful non-invasive method for assessing coronary vascular function in patients with angina and a normal coronary angiogram. (orig.)

Effect of the glucagon-like peptide-1 analogue liraglutide on coronary microvascular function in patients with type 2 diabetes – a randomized, single-blinded, cross-over pilot study

DEFF Research Database (Denmark)

Faber, Rebekka; Zander, Mette; Pena, Adam

2015-01-01

dipyridamole induced stress. Peripheral microvascular endothelial function was assessed by Endo-PAT2000®. Interventions were compared by two-sample t-test after ensuring no carry over effect. RESULTS: A total of 24 patients were included. Twenty patients completed the study (15 male; mean age 57 ± 9; mean BMI...

Validation of [1-11C]acetate as a tracer for noninvasive assessment of oxidative metabolism with positron emission tomography in normal, ischemic, postischemic, and hyperemic canine myocardium

International Nuclear Information System (INIS)

Armbrecht, J.J.; Buxton, D.B.; Schelbert, H.R.

1990-01-01

Extraction and clearance kinetics of [1-11C]acetate were examined in 65 experiments in 30 open-chest dogs. Twenty-nine studies were performed at control, 13 during ischemia, eight after reperfusion, 13 during dipyridamole-induced hyperemia, and two during alteration of cardiac workload. [1-11C]acetate was injected directly into the left anterior descending coronary artery, and myocardial tissue-time activity curves were recorded with a gamma probe. The single-pass extraction fraction averaged 64.2 +/- 9.7% in control, 65.3 +/- 9.1% in ischemia, 70.0 +/- 4.4% in reperfusion, and 46.5 +/- 7.4% in dipyridamole-induced hyperemia groups. 11C clearance was biexponential in all cases. The rate constant k1 for the first rapid clearance phase correlated closely with myocardial oxygen consumption (r = 0.94) in control, ischemia, reperfusion, and dipyridamole-induced hyperemia groups. Monoexponential fitting of only the first linear part of the clearance curve yielded the rate constant kmono, which also correlated with myocardial oxygen consumption (r = 0.96). Arterial lactate concentrations and the amount of free fatty acid oxygen equivalents consumed by the myocardium were shown to have a small but statistically significant impact on the relation between [1-11C]acetate clearance rate constants and myocardial oxygen consumption. The fraction of 14CO2 activity contributing to overall 14C activity leaving the myocardium after simultaneous injection of [1-14C]acetate (n = 24) was relatively high in all cases , indicating that externally measured 11C clearance corresponds to CO2 production and thus to tricarboxylic acid cycle activity. In conclusion, the results validate the use of [1-11C]acetate as a tracer of oxidative myocardial metabolism for use with positron emission tomography

Determinants of the response of left ventricular ejection fraction to vasodilator stress in electrocardiographically gated {sup 82}rubidium myocardial perfusion PET

Energy Technology Data Exchange (ETDEWEB)

Brown, Tracy L.Y.; Merrill, Jennifer; Bengel, Frank M. [Johns Hopkins University, Department of Radiology and Radiological Sciences, Division of Nuclear Medicine, Baltimore, MD (United States); Volokh, Lana [GE Healthcare, Haifa (Israel)

2008-02-15

Myocardial perfusion imaging with {sup 82}Rb PET allows for ECG-gated studies to be obtained early after radiotracer injection, capturing ventricular function close to peak pharmacologic action of dipyridamole. This is different from gated SPECT and may potentially provide additional diagnostic information. We sought to identify potential correlates of the PET-derived ejection fraction response to vasodilator stress. One hundred ten consecutive patients undergoing {sup 82}Rb PET myocardial perfusion imaging during evaluation for coronary artery disease were included. Using a GE Discovery STRx PET-CT scanner, ECG-gated images (eight bins) were obtained at rest and 4 min after dipyridamole infusion, 90 s after infusion of 1,480-2,220 MBq of {sup 82}Rb. Summed rest, stress, and difference scores (SRS, SSS, and SDS) were determined using a five-point scoring system and 20-segment model. Ejection fraction was calculated using automated QGS software. Significant reversibility (SDS {>=} 4) was found in 23 patients (21%). Mean LVEF in all patients was 47 {+-} 13% at rest and 53 {+-} 13% during dipyridamole. LVEF increased in 89 patients, and decreased in 17 patients during vasodilation. The change in LVEF was inversely correlated with SDS (r = -0.26; p = 0.007). Additionally, it was inversely correlated with resting LVEF (r = -0.20; p = 0.03) and SSS (r = -0.25; p = 0.009). No significant correlations were observed with SRS, heart rate, blood pressure, age, hypertension, hypercholesterolemia, or pretest likelihood of disease. At multivariate regression analysis, SDS was an independent predictor of the change in LVEF. Gated {sup 82}Rb PET during pharmacologic stress allows for assessment of the functional response to vasodilation. The magnitude of LVEF increase is determined by stress perfusion/reversible perfusion defects. Functional response to hyperemia may thus be incorporated in future evaluations of diagnostic and prognostic algorithms based on {sup 82}Rb PET. (orig.)

Prevalence of Ex Vivo High On-treatment Platelet Reactivity on Antiplatelet Therapy after Transient Ischemic Attack or Ischemic Stroke on the PFA-100(®) and VerifyNow(®).

LENUS (Irish Health Repository)

Kinsella, Justin A

2012-09-12

BACKGROUND: The prevalence of ex vivo high on-treatment platelet reactivity (HTPR) to commonly prescribed antiplatelet regimens after transient ischemic attack (TIA) or ischemic stroke is uncertain. METHODS: Platelet function inhibition was simultaneously assessed with modified light transmission aggregometry (VerifyNow; Accumetrics Inc, San Diego, CA) and with a moderately high shear stress platelet function analyzer (PFA-100; Siemens Medical Solutions USA, Inc, Malvern, PA) in a pilot, cross-sectional study of TIA or ischemic stroke patients. Patients were assessed on aspirin-dipyridamole combination therapy (n = 51) or clopidogrel monotherapy (n = 25). RESULTS: On the VerifyNow, HTPR on aspirin was identified in 4 of 51 patients (8%) on aspirin-dipyridamole combination therapy (≥550 aspirin reaction units on the aspirin cartridge). Eleven of 25 (44%) patients had HTPR on clopidogrel (≥194 P2Y12 reaction units on the P2Y12 cartridge). On the PFA-100, 21 of 51 patients (41%) on aspirin-dipyridamole combination therapy had HTPR on the collagen-epinephrine (C-EPI) cartridge. Twenty-three of 25 patients (92%) on clopidogrel had HTPR on the collagen-adenosine diphosphate (C-ADP) cartridge. The proportion of patients with antiplatelet HTPR was lower on the VerifyNow than PFA-100 in patients on both regimens (P < .001). CONCLUSIONS: The prevalence of ex vivo antiplatelet HTPR after TIA or ischemic stroke is markedly influenced by the method used to assess platelet reactivity. The PFA-100 C-ADP cartridge is not sensitive at detecting the antiplatelet effects of clopidogrel ex vivo. Larger prospective studies with the VerifyNow and with the PFA-100 C-EPI and recently released Innovance PFA P2Y cartridges (Siemens Medical Solutions USA, Inc) in addition to newer tests of platelet function are warranted to assess whether platelet function monitoring predicts clinical outcome in ischemic cerebrovascular disease.

Granulocyte colony-stimulating factor and drugs elevating extracellular adenosine synergize to enhance haematopoietic reconstitution in irradiated mice

Energy Technology Data Exchange (ETDEWEB)

Pospisil, M.; Hofer, M.; Netikova, J.; Hola, J.; Vacek, A. [Academy of Sciences of the Czech Republic, Inst. of Biophysics, Brno (Czech Republic); Znojil, V.; Vacha, J. [Masaryk Univ., Medical Faculty, Brno (Czech Republic)

1998-03-01

The activation of adenosine receptors has recently been demonstrated to stimulate haematopoiesis. In the present study, we investigated the ability of drugs elevating extracellular adenosine to influence curative effects of granulocyte colony-stimulating factor (G-CSF) in mice exposed to a sublethal dose of 4 Gy of {sup 60}Co radiation. Elevation of extracellular adenosine in mice was induced by the combined administration of dipyridamole, a drug inhibiting the cellular uptake of adenosine, and adenosine monophosphate (AMP), an adenosine prodrug. The effects of dipyridamole plus AMP, and G-CSF, administered either alone or in combination, were evaluated. The drugs were injected to mice in a 4-d treatment regimen starting on d 3 after irradiation and the haematopoietic response was evaluated on d 7, 10, 14, 18 and 24 after irradiation. While the effects of G-CSF on the late maturation stages of blood cells, appearing shortly after the completion of the treatment, were not influenced by dipyridamole plus AMP, positive effects of the combination therapy occurred in the post-irradiation recovery phase which is dependent on the repopulation of haematopoietic stem cells. This was indicated by the significant elevation of counts of granulocyte-macrophage progenitor cells (GM-CFC) and granulocytic cells in the bone marrow (d 14), of GM-CFC (d 14), granulocytic and erythroid cells (d 14 and 18) in the spleen, and of neutrophils (d 18), monocytes (d 14 and 18) and platelets (d 18) in the peripheral blood. These effects suggest that the repopulation potential of the combination therapy lies in a common multi-lineage cell population. The results of this study implicate the promising possibility to enhance the curative effects of G-CSF under conditions of myelosuppressive state induced by radiation exposure. (au) 43 refs.

Granulocyte colony-stimulating factor and drugs elevating extracellular adenosine synergize to enhance haematopoietic reconstitution in irradiated mice

International Nuclear Information System (INIS)

Pospisil, M.; Hofer, M.; Netikova, J.; Hola, J.; Vacek, A.; Znojil, V.; Vacha, J.

1998-01-01

The activation of adenosine receptors has recently been demonstrated to stimulate haematopoiesis. In the present study, we investigated the ability of drugs elevating extracellular adenosine to influence curative effects of granulocyte colony-stimulating factor (G-CSF) in mice exposed to a sublethal dose of 4 Gy of 60 Co radiation. Elevation of extracellular adenosine in mice was induced by the combined administration of dipyridamole, a drug inhibiting the cellular uptake of adenosine, and adenosine monophosphate (AMP), an adenosine prodrug. The effects of dipyridamole plus AMP, and G-CSF, administered either alone or in combination, were evaluated. The drugs were injected to mice in a 4-d treatment regimen starting on d 3 after irradiation and the haematopoietic response was evaluated on d 7, 10, 14, 18 and 24 after irradiation. While the effects of G-CSF on the late maturation stages of blood cells, appearing shortly after the completion of the treatment, were not influenced by dipyridamole plus AMP, positive effects of the combination therapy occurred in the post-irradiation recovery phase which is dependent on the repopulation of haematopoietic stem cells. This was indicated by the significant elevation of counts of granulocyte-macrophage progenitor cells (GM-CFC) and granulocytic cells in the bone marrow (d 14), of GM-CFC (d 14), granulocytic and erythroid cells (d 14 and 18) in the spleen, and of neutrophils (d 18), monocytes (d 14 and 18) and platelets (d 18) in the peripheral blood. These effects suggest that the repopulation potential of the combination therapy lies in a common multi-lineage cell population. The results of this study implicate the promising possibility to enhance the curative effects of G-CSF under conditions of myelosuppressive state induced by radiation exposure. (au)

Membranoproliferative glomerulonephritis. A prospective clinical trial of platelet-inhibitor therapy

International Nuclear Information System (INIS)

Donadio, J.V. Jr.; Anderson, C.F.; Mitchell, J.C.; Holley, K.E.; Ilstrup, D.M.; Fuster, V.; Chesebro, J.H.

1984-01-01

Forty patients with Type I membranoproliferative glomerulonephritis were treated for one year with dipyridamole, 225 mg per day, and aspirin, 975 mg per day, in a prospective, randomized, double-blind, placebo-controlled study. At the base line, the half-life of 51 Cr-labeled platelets was reduced in 12 of 17 patients. The platelet half-life became longer and renal function stabilized in the treated group, as compared with the placebo group, suggesting a relation between platelet consumption and the glomerulopathy. The glomerular filtration rate, determined by iothalamate clearance, was better maintained in the treated group (average decrease, 1.3 ml per minute per 1.73 m 2 of body-surface area per 12 months) than in the placebo group (average decrease, 19.6). Fewer patients in the treated group than in the placebo group had progression to end-stage renal disease (3 of 21 after 62 months as compared with 9 of 19 after 33 months). The data suggest that dipyridamole and aspirin slowed the deterioration of renal function and the development of end-stage renal disease

Complications during pharmacological stress echocardiography: a video-case series

Directory of Open Access Journals (Sweden)

Bigi Riccardo

2005-09-01

Full Text Available Abstract Background Stress echocardiography is a cost-effective tool for the modern noninvasive diagnosis of coronary artery disease. Several physical and pharmacological stresses are used in combination with echocardiographic imaging, usually exercise, dobutamine and dipyridamole. The safety of a stress is (or should be a major determinant in the choice of testing. Although large scale single center experiences and multicenter trial information are available for both dobutamine and dipyridamole stress echo testing, complications or side effects still can occur even in the most experienced laboratories with the most skilled operators. Case presentation We decided to present a case collection of severe complications during pharmacological stress echo testing, including a ventricular tachycardia, cardiogenic shock, transient ischemic attack, torsade de pointe, fatal ventricular fibrillation, and free wall rupture. Conclusion We believe that, in this field, every past complication described is a future complication avoided; what happens in your lab is more true of what you read in journals; and Good Clinical Practice is not "not having complications", but to describe the complications you had.

Myocardial scintigraphy with 201Tl in combination with pharmacological tests in the diagnosis of coronary heart diseases

International Nuclear Information System (INIS)

Tokareva, E.A.; Sergienko, V.B.; Sidorenko, B.A.

1989-01-01

The paper presents the results from examination of 67 patients with coronary heart disease verified by a bicycle ergometric tests, 48 underwent 201 Tl myocardial scintigraphy along with a dipyridamole test, 19, the scintigraphy in combination with an isoproterenol test. The feasibilities of employing the procedures in the diagnosis of coronary heart disease were compared by statistic analysis

Elevation of extracellular adenosine mobilizes haematopoietic progenitor cells and granulocytes into peripheral blood and enhances the mobilizing effects of granulocyte colony-stimulating factor

Czech Academy of Sciences Publication Activity Database

Hofer, Michal; Weiterová, Lenka; Vacek, Antonín; Znojil, V.; Pospíšil, Milan; Vácha, J.

2003-01-01

Roč. 71, č. 3 (2003), s. 204-210 ISSN 0902-4441 R&D Projects: GA ČR GA305/02/0423; GA AV ČR IBS5004009; GA AV ČR KSK5011112 Institutional research plan: CEZ:AV0Z5004920 Keywords : extracellular adenosine * dipyridamole * adenosine monophosphate Subject RIV: BO - Biophysics Impact factor: 1.714, year: 2003

The value of regional wall motion abnormalities on gated mycardiac perfusion imaging in perfusion imaging in predicting angiographic stenoses of coronary artery

International Nuclear Information System (INIS)

Yao Lixin; Liu Binbin

2007-01-01

Objective: To determine the possible level of angiographic stenoses of coronary artery at which reversible regional wall motion abnormalities (RWMA) are present on 99m Tc-sestamibi ( 99m Tc-MIBI)-gated myocardial perfusion imaging (MPI). Methods: ninty patients undergoing coronary angiography MPI within two weeks were recruited. A five grades and nine segments marking system was introduced to assess the RWMA and thickening of left ventricles. Results: The sensitivity of reversible RWMA for detecting ≥75% angiographic stenoses was 64%,with a specificity of 95% and positive predictive value of 97%. The presence of reversible RWMA was able to stratify patients with severe angiographic stenoses of 75% or more from those less than 75% with high positive predictive value. A good correlation was noted between the presence of reversible RWMA and the coronary artery jeopardy score. Multivariate analysis showed that the post-stress RWMA and reversible RWMA scores and positive dipyridamole-stress exercise electrocardiogram(ECG) were significant predictors of angiographic severity. Conclusions: Reversible RWMA, as shown by dipyridamole stress 99m Tc-MIBI MPI, is a significant predictor of angiographic disease with very high specificity and adds incremental value to MPI for the assessment of angiographic severity. (authors)

Pharmacologic intervention as an alternative to exercise stress

International Nuclear Information System (INIS)

Gould, K.L.

1987-01-01

Although thallium exercise imaging has served an important role in clinical cardiology, it is significantly limited by suboptimal sensitivity and specificity, particularly in asymptomatic man. The increasing recognition of silent myocardial ischemia, the significant prevalence of coronary artery disease in asymptomatic middle age men, and the frequent occurrence of myocardial infarction without preceding symptoms in 60% of cases emphasizes the need for a more definitive, noninvasive diagnostic test for the presence of coronary artery disease suitable for screening in asymptomatic or symptomatic patients. Intravenous dipyridamole combined with handgrip stress provides a potent stimulus for purposes of diagnostic perfusion imaging. Although planar and single photon emission computed tomography (SPECT) imaging also have played an important role, these techniques are seriously hindered by their inability to quantitate radiotracer uptake or image modest differences in maximum relative flow caused by coronary artery stenosis. Accordingly, the combination of dipyridamole-handgrip stress with positron imaging of myocardial perfusion has become a powerful diagnostic tool suitable for routine clinical use. With the availability of generator-produced rubidium-82, dedicated clinically oriented positron cameras, the routine application of positron imaging to clinical cardiology has become feasible. 75 references

Imaging diagnosis of portal vein thrombosis following splenectomy in 23 patients with hepatocellular carcinoma

International Nuclear Information System (INIS)

Yamashita, Kohsuke; Takayasu, Kenichi; Muramatsu, Yukio; Moriyama, Noriyuki; Yamada, Tatsuya; Makuuchi, Masatoshi; Hasegawa, Hiroshi

1988-01-01

During the past two years, the postoperative development of portal vein thrombosis (PVT) following splenectomy with simultaneous or subsequent hepatectomy for hepatocellular carcinoma was detected in 3 of 23 patients (13 %) utilizing ultrasound and/or computed tomography. These 3 patients were clinically asymptomatic. Two of these patients were treated medically with urokinase, and aspirin or dipyridamole, with documented resolution of the PVT by ultrasound. (author)

Myocardial perfusion with multi-detector computed tomography: quantitative evaluation

International Nuclear Information System (INIS)

Carrascosa, Patricia M.; Vallejos, J.; Capunay, Carlos M.; Deviggiano, A.; Carrascosa, Jorge M.

2007-01-01

The objective of this work is to evaluate the skill of multidetector computer tomography, to quantify the different patterns of intensification during the evaluation of the myocardial perfusion. 45 patients were studied with suspicion of cardiovascular disease. Multi-detector computed tomography was utilized on patients at rest and in effort with pharmacological stress, after the administration of dipyridamole. Also they were evaluated using nuclear medicine [es

[No role for oral anticoagulants (target INR: 2.0-3.0) after transient ischaemic attack or cerebral infarction of arterial origin; the 'European/Australasian stroke prevention in reversible ischaemia trial' (ESPRIT)].

Science.gov (United States)

De Schryver, E L L M; Halkes, P H A

2008-02-23

The 'European/Australasian stroke prevention in reversible ischaemia trial' (ESPRIT) aimed to determine whether oral anticoagulation of moderate intensity (target international normalised ratio (INR): 2.0-3.0) is more effective than acetylsalicylic acid in preventing future vascular events in patients with transient ischaemic attack (TIA) or minor stroke of arterial origin. International, multicentre randomised clinical trial. Patients were randomised within 6 months of TIA or minor stroke of arterial origin to oral anticoagulants (target INR: 2.0-3.0; n = 536) or acetylsalicylic acid (30-325 mg daily; n = 532). The primary endpoint was a composite of vascular death, non-fatal stroke, non-fatal myocardial infarction or major bleeding complications. In a post hoc analysis, the efficacy of anticoagulants was compared with that of the combination of acetylsalicylic acid and dipyridamole (200 mg twice daily), a third arm of ESPRIT. Treatment was unblinded, but auditing of endpoints was blinded. Data were analysed on an intent-to-treat basis. The comparison of anticoagulants and acetylsalicylic acid was stopped prematurely because the combination of acetylsalicylic acid and dipyridamole was found to be more effective than acetylsalicylic acid alone. The mean duration of follow-up was 4.6 years (SD: 2.2). The mean INR was 2.57 (SD: 0.86; nearly 70% of the time within target range). The primary endpoint occurred in 99 patients (19%) in the anticoagulation group and 98 patients (18%) in the acetylsalicylic acid group (hazard ratio: 1.02; 95% CI: 0.77-1.35). The hazard ratio was 0.73 (95% CI: 0.52-1.01) for ischaemic events and 2.56 (95% CI: 1.48-4.43) for major bleeding complications. The hazard ratio for the primary outcome event comparing anticoagulants with the combination of acetylsalicylic acid and dipyridamole was 1.31 (95% CI: 0.98-1.75). Oral anticoagulants (target INR: 2.0-3.0) were not more effective than acetylsalicylic acid in the secondary prevention of

Assessment of coronary flow reserve by sestamibi imaging in patients with typical chest pain and normal coronary arteries

Energy Technology Data Exchange (ETDEWEB)

Storto, Giovanni; Sorrentino, Anna R.; Pellegrino, Teresa; Liuzzi, Raffaele; Cuocolo, Alberto [University Federico II, Department of Biomorphological and Functional Sciences, Institute of Biostructures and Bioimages of the National Council of Research, Naples (Italy); Petretta, Mario [University Federico II, Department of Internal Medicine, Cardiovascular and Immunological Sciences, Naples (Italy)

2007-08-15

We assessed coronary flow reserve (CFR) by sestamibi imaging in patients with typical chest pain, positive exercise stress test and normal coronary vessels. Thirty-five patients with typical chest pain and normal angiogram and 12 control subjects with atypical chest pain underwent dipyridamole/rest {sup 99m}Tc-sestamibi imaging. Myocardial blood flow (MBF) was estimated by measuring first transit counts in the pulmonary artery and myocardial counts from SPECT images. Estimated CFR was expressed as the ratio of stress to rest MBF. Rest MBF and CFR were corrected for rate-pressure product (RPP) and expressed as normalised MBF (MBF{sub n}) and normalised CFR (CFR{sub n}). Coronary vascular resistances (CVR) were calculated as the ratio between mean arterial pressure and estimated MBF. At rest, estimated MBF and MBF{sub n} were lower in controls than in patients (0.98 {+-} 0.4 vs 1.30 {+-} 0.3 counts/pixel/s and 1.14 {+-} 0.5 vs 1.64 {+-} 0.6 counts/pixel/s, respectively, both p < 0.02). Stress MBF was not different between controls and patients (2.34 {+-} 0.8 vs 2.01 {+-} 0.7 counts/pixel/s, p=NS). Estimated CFR was 2.40 {+-} 0.3 in controls and 1.54 {+-} 0.3 in patients (p < 0.0001). After correction for the RPP, CFR{sub n} was still higher in controls than in patients (2.1 {+-} 0.5 vs 1.29 {+-} 0.5, p < 0.0001). At baseline, CVR values were lower (p < 0.01) in patients than in controls. Dipyridamole-induced changes in CVR were greater (p < 0.0001) in controls (-63%) than in patients (-35%). In the overall study population, a significant correlation between dipyridamole-induced changes in CVR and CFR was observed (r = -0.88, p < 0.0001). SPECT might represent a useful non-invasive method for assessing coronary vascular function in patients with angina and a normal coronary angiogram. (orig.)

Recombinant Amphiphilic Protein Micelles for Drug Delivery

OpenAIRE

Kim, Wookhyun; Xiao, Jiantao; Chaikof, Elliot L.

2011-01-01

Amphiphilic block polypeptides can self-assemble into a range of nanostructures in solution, including micelles and vesicles. Our group has recently described the capacity of recombinant amphiphilic diblock copolypeptides to form highly stable micelles. In this report, we demonstrate the utility of protein nanoparticles to serve as a vehicle for controlled drug delivery. Drug-loaded micelles were produced by encapsulating dipyridamole as a model hydrophobic drug with anti-inflammatory activit...

Myocardium repair with stem cell therapy

International Nuclear Information System (INIS)

Peix, Amalia; Hidalgo, Jose; Dorticos, Elvira; Llerena, Lorenzo; Paredes, Angel; Torres, Maritza; Macias, Consuelo; Del Valle, Lazaro; Cabrera, Lazaro O; Carrillo, Regla; Mena, Eric; Fernandez, Yoel

2006-01-01

With the aim of assessing the efficacy of bone marrow-derived stem cells transplantation in patients with myocardial infarction and severe chronic heart failure through nuclear cardiology techniques, 15 revascularized patients were studied: nine (Group I) received autologous bone marrow-derived stem cells. The other six were controls (Group II). All underwent a clinical evaluation, radionuclide ventriculography, and gated-SPECT myocardial perfusion scintigraphy (MIBI-technetium99m, two-day protocol: dipyridamole - rest), before and three months after the procedure. At three months there was a clinical improvement in 89% of patients from Group I. The left ventricular ejection fraction increased: from 32±9% to 44±13% (p=0.03; Group I) and from 38±2% to 48±14% (p NS; Group II). The peak filling rate improved from 120±11 to 196±45 EDV/sec (p=0.03; Group I). The dipyridamole summed score diminished significantly only in Group I (from 35±5 to 23±14; p=0.02). The perfusion improvement was related to the implantation site in 60% of cases. We conclude that the bone marrow-derived stem cells transplantation is effective in patients with severe chronic heart failure of ischemic origin (au)

Evaluating the prevalence of silent coronary artery disease in asymptomatic patients with spinal cord injury

International Nuclear Information System (INIS)

Lee, Chee-Siong; Lu, Ye-Hsu; Lee, Shuo-Tsan; Lin, Ching-Cheng; Ding, Hueisch-Jy

2006-01-01

To evaluate the prevalence of coronary artery disease (CAD) in patients with spinal cord injury (SCI), 47 clinically asymptomatic SCI patients received thallium-201 myocardial perfusion single photon emission computed tomography (Tl-201 SPECT) after dipyridamole administration for the diagnosis of CAD. There were 4 groups as follows; group 1: 13 patients with quadriplegia and complete SCI, group 2: 11 patients with quadriplegia and incomplete SCI, group 3: 11 patients with paraplegia and complete SCI, and group 4: 12 patients with paraplegia and incomplete SCI. There were no significant differences in sex distribution, ages, SCI duration, or CAD risk factors among the SCI patients in the 4 groups. All Tl-201 SPECT images were interpreted by the agreement of 2 experienced nuclear medicine physicians without prior knowledge of the patients' histories. A total of 30 of 47 (63.8%) SCI patients had abnormal Tl-201 SPECT findings. Among the 4 groups of SCI patients, those in groups 1 and 4 had the significantly highest and lowest prevalences of abnormal Tl-201 SPECT findings, respectively. We concluded that combined quadriplegia and complete SCI is an important CAD risk factor in SCI patients based on the objective evidence of intravenous dipyridamole cardiac stress testing with Tl-201 SPECT. (author)

ESPRIT study design and outcomes--a critical appraisal.

Science.gov (United States)

Einhäupl, Karl

2007-02-01

Evidence is needed to guide therapeutic decisions on patients who had ischaemic cerebral events. The recently published European/Australasian Stroke Prevention in Reversible Ischaemia Trial (ESPRIT), an open-label randomised controlled study, compared long-term treatment of patients randomised to aspirin 30-325 mg daily with (n = 1363) or without (n = 1376) dipyridamole 200 mg twice daily. The study found the combination to be superior to aspirin alone (13% vs. 16% events in a composite endpoint of vascular death, non-fatal stroke, non-fatal myocardial infarction, or major bleeding; hazard ratio 0.8; 95% confidence interval 0.66-0.98). In the interpretation of the results, criticism has been raised related to the study design (open-label, change during the study), the study conduct (half of the aspirin patients underdosed, 33% drop-out rate in the combination group, missing information on potential confounders such as protective concomitant medication), and the outcomes (lack of differences in the efficacy outcomes between the intent-to-treat and the on-treatment populations, lack of differences in minor bleedings between treatment groups, borderline statistical significance of primary study endpoint). Further studies are needed to determine the place of aspirin/dipyridamole combinations in the secondary prevention of stroke.

Indium-111 platelet imaging for detection of platelet deposition in abdominal aneurysms and prosthetic arterial grafts

International Nuclear Information System (INIS)

Ritchie, J.L.; Stratton, J.R.; Thiele, B.; Haminton, G.W.; Warrick, L.N.; Huang, T.W.; Harker, L.A.

1981-01-01

Thirty-four platelet imaging studies were performed in 23 patients to determine whether platelet deposition could be detected in patients with vascular aneurysms (18 patients) or in patients in whom Dacron prosthetic grafts had been placed (5 patients). In patients in whom abnormal platelet deposition was detected, the effect of administration of platelet-active drugs on platelet deposition was examined. Of the 18 patients with an aneurysm, 12 had equivocally positive studies on initial imaging and 2 had equivocally positive images. Of five patients with Dacron arterial grafts in place, four had diffuse platelet deposition in the grafts; the fifth patient had a platelet deposition only in a pseudoaneurysm. Eight patients with an abdominal aneurysm and positive or equivocally positive baseline images were restudied during platelet-active drug therapy either with aspirin plus dipyridamole (seven patients) or with sulfinpyrazone (four patients). No patient studied during treatment with aspirin plus dipyridamole had detectably decreased platelet deposition compared with baseline determinations. In contrast, two of four patients studied while receiving sulfinpyrazone showed decreased platelet deposition. Thus, platelet imaging may be of value for studying platelet physiology in vivo and for assessing platelet-active drugs and the thrombogenicity of prosthetic graft materials in human beings

The use of coronary vasodilators in myocardial imaging with 43K

International Nuclear Information System (INIS)

Markov, A.K.; Smith, R.O.; Oglethorpe, N.C.; Lehan, P.H.; Hellems, H.K.

1980-01-01

As an alternative procedure to the exercise stress test used in myocardial scanning, vasoactive drugs were employed to elicit deficits in blood flow to myocardial regions supplied by stenotic arteries. The data were collected from 35 dogs, some of which had partial stenosis on either major branch of the left coronary artery, and others which had Ameroid constrictor implants. The effects of lidoflazine, dipyridamole, and nitroglycerin on coronary hemodynamics and myocardial dispersion of 43 K in animals with partial stenosis were evaluated in ten acute experiments. In the pilot studies, four rapid serial rectilinear control scans from 43 K (750 μCi) were reported; dipyridamole, lidoflazine, or nitroglycerin were then administered intravenously. When the selected drug reached a peak vasodilatative effect, a second equal bolus of 43 K was given and four additional scans recorded. The control scans from dogs with partial stenosis or an Ameroid constrictor showed homogeneous distribution of the myocardial 43 K. When drugs were used, the region supplied by compromised circulation became apparent because of lower counts when compared to the normally perfused ones. Coronary vasodilators, as opposed to postexercise in myocardial imaging, have a lesser effect on cardiac dynamics, peripheral hemodynamics, and also double the 43 K uptake in normally perfused myocardium. (orig.) [de

Antitrombotisk behandling ved iskaemisk apopleksi og transitorisk cerebral iskaemi

DEFF Research Database (Denmark)

Overgaard, Karsten; Poulsen, Tina Svenstrup; Husted, Steen E

2007-01-01

In acute ischemic stroke and transient ischemic attack (TIA), aspirin is recommended to all patients (except immediately following thrombolysis). Heparin and anticoagulant therapy using vitamin K antagonists should be avoided in the acute phase. Secondary preventive antithrombotic treatment...... includes anticoagulation in patients with cardioembolic stroke and antiplatelet agents aspirin possibly combined with dipyridamole or clopidogrel alone in patients with non-cardioembolic stroke. Other individual risks may modify this treatment regimen. Udgivelsesdato: 2007-Oct-1...

Platelet aggregation inhibitors in primary and secondary prevention of ischemic stroke

Directory of Open Access Journals (Sweden)

von der Schulenburg, Johann-Matthias

2006-04-01

Full Text Available Background: The ischaemic stroke (IS is one of the most frequent cause of death in Germany. Besides of non-drug many drug-based interventions are used in primary or secondary prevention of IS, among them the thrombocyte aggregation inhibitors (TAI. Objectives: The evaluation addresses the questions on medical efficacy and cost-effectiveness of the TAI administration in the prevention of IS as compared to the management of risk factors alone as well as to the use of anticoagulant drugs. Methods: The literature search for articles published after 1997 was conducted in December 2003 in the most important medical and economic databases. The medical analysis was performed on the basis of the most up-to date meta-analyses of randomised controlled trials (RCT as well as of new published RCT. The data from the studies for stroke, bleeding complications as well as for the combined endpoint "severe vascular events" (SVE: death or stroke or myocardial infarction were summarised in meta-analyses.In order to include grey literature contact has been taken up with the pharmaceutical manufacturers of TAI. Results are presented in a descriptive way. Results: The medical analysis included data from 184 RCT (vs. placebo and from 22 RCT (vs. anticoagulant drugs. The absolute reduction of IS (4.8% vs. 6.6%; p<0,00001 and SVE (10.0% vs. 12.4%; p<0,00001 were definitely higher than the absolute increase of bleeding complications (1.6% vs. 0.9%; p<0,00001, but relatively similar to this absolute increase in a subpopulation with a low risk for SVE. With regard to the stroke prevention, evidence of efficacy could be yielded for acetylsalicil acid (ASA, dipyridamole, cilostazol, ridogrel and the combination ASA with dipyridamole. ASA is less effective than anticoagulants in the prevention of ischaemic stroke in atrial fibrillation, however, it causes fewer bleeding complications.Low dosed ASA can be considered cost-effective in secondary prevention of ischemic stroke

Medium intensity oral anticoagulants versus aspirin after cerebral ischaemia of arterial origin (ESPRIT): a randomised controlled trial.

Science.gov (United States)

Halkes, P H A; van Gijn, J; Kappelle, L J; Koudstaal, P J; Algra, A

2007-02-01

Oral anticoagulants are better than aspirin for secondary prevention after myocardial infarction and after cerebral ischaemia in combination with non-rheumatic atrial fibrillation. The European/Australasian Stroke Prevention in Reversible Ischaemia Trial (ESPRIT) aimed to determine whether oral anticoagulation with medium intensity is more effective than aspirin in preventing future vascular events in patients with transient ischaemic attack or minor stroke of presumed arterial origin. In this international, multicentre trial, patients were randomly assigned within 6 months after a transient ischaemic attack or minor stroke of presumed arterial origin either anticoagulants (target INR range 2.0-3.0; n=536) or aspirin (30-325 mg daily; n=532). The primary outcome was the composite of death from all vascular causes, non-fatal stroke, non-fatal myocardial infarction, or major bleeding complication, whichever occurred first. In a post hoc analysis anticoagulants were compared with the combination of aspirin and dipyridamole (200 mg twice daily). Treatment was open, but auditing of outcome events was blinded. Primary analysis was by intention to treat. This study is registered as an International Standard Randomised Controlled Trial (number ISRCTN73824458) and with ClinicalTrials.gov (NCT00161070). The anticoagulants versus aspirin comparison of ESPRIT was prematurely ended because ESPRIT reported previously that the combination of aspirin and dipyridamole was more effective than aspirin alone. Mean follow-up was 4.6 years (SD 2.2). The mean achieved INR was 2.57 (SD 0.86). A primary outcome event occurred in 99 (19%) patients on anticoagulants and in 98 (18%) patients on aspirin (hazard ratio [HR] 1.02, 95% CI 0.77-1.35). The HR for ischaemic events was 0.73 (0.52-1.01) and for major bleeding complications 2.56 (1.48-4.43). The HR for the primary outcome event comparing anticoagulants with the combination treatment of aspirin and dipyridamole was 1.31 (0.98-1.75). Oral

Noninvasive detection and assessment of coronary artery disease by dipyridamloe thallium-201 imaging

International Nuclear Information System (INIS)

Jiang Maosong

1988-01-01

Dipyridamole (DP) thallium-201 perfusion scintigraphy was performed in 73 patients. IV DP (0.56 mg/kg) infused over 4 min. resulted in an increases in mean HR from 74 +- 12 bpm to a peak of 86 +- 12 bpm (p 201 Tl scintigraphy appears highly sensitive for the diagnosis of coronary artery highly sensitive for the diagnosis of coronary artery disease and provides a useful alternative test for patients who are unable to perform maximal exercise

Thallium-201 is comparable to technetium-99m-sestamibi for estimating cardiac function in patients with abnormal myocardial perfusion imaging

Directory of Open Access Journals (Sweden)

Ming-Che Wu

2015-11-01

Full Text Available We analyzed the left-ventricular functional data obtained by cardiac-gated single-photon emission computed tomography myocardial perfusion imaging (MPI with thallium-201 (Tl-201 and technetium-99m-sestamibi (MIBI protocols in different groups of patients, and compared the data between Tl-201 and MIBI. Two hundred and seventy-two patients undergoing dipyridamole stress/redistribution Tl-201 MPI and 563 patients undergoing 1-day rest/dipyridamole stress MIBI MPI were included. Higher mean stress ejection fraction (EF, rest EF, and change in EF (ΔEF were noticed in the normal MPI groups by both Tl-201 and MIBI protocols. Higher mean EF was observed in the females with normal MPI results despite their higher mean age. Comparisons between the Tl-201 and MIBI groups suggested a significant difference in all functional parameters, except for the rest end diastolic volume/end systolic volume and ΔEF between groups with negative MPI results. For the positive MPI groups, there was no significant difference in all parameters, except for the change in end diastolic volume and change in end systolic volume after stress between both protocols. The Tl-201 provides comparable left-ventricular functional data to MIBI cardiac-gated single-photon emission computed tomography in patients with positive MPI results, and may therefore be undertaken routinely for incremental functional information that is especially valuable to this patient group.

Evaluation of the light scattering and the turbidity microtiter plate-based methods for the detection of the excipient-mediated drug precipitation inhibition.

Science.gov (United States)

Petruševska, Marija; Urleb, Uroš; Peternel, Luka

2013-11-01

The excipient-mediated precipitation inhibition is classically determined by the quantification of the dissolved compound in the solution. In this study, two alternative approaches were evaluated, one is the light scattering (nephelometer) and other is the turbidity (plate reader) microtiter plate-based methods which are based on the quantification of the compound precipitate. Following the optimization of the nephelometer settings (beam focus, laser gain) and the experimental conditions, the screening of 23 excipients on the precipitation inhibition of poorly soluble fenofibrate and dipyridamole was performed. The light scattering method resulted in excellent correlation (r>0.91) between the calculated precipitation inhibitor parameters (PIPs) and the precipitation inhibition index (PI(classical)) obtained by the classical approach for fenofibrate and dipyridamole. Among the evaluated PIPs AUC100 (nephelometer) resulted in only four false positives and lack of false negatives. In the case of the turbidity-based method a good correlation of the PI(classical) was obtained for the PIP maximal optical density (OD(max), r=0.91), however, only for fenofibrate. In the case of the OD(max) (plate reader) five false positives and two false negatives were identified. In conclusion, the light scattering-based method outperformed the turbidity-based one and could be reliably used for identification of novel precipitation inhibitors. Copyright © 2013 Elsevier B.V. All rights reserved.

Roles of myocardial blood volume and flow in coronary artery disease: an experimental MRI study at rest and during hyperemia

International Nuclear Information System (INIS)

McCommis, Kyle S.; Goldstein, Thomas A.; Pilgram, Thomas; Abendschein, Dana R.; Misselwitz, Bernd; Gropler, Robert J.; Zheng, Jie

2010-01-01

To validate fast perfusion mapping techniques in a setting of coronary artery stenosis, and to further assess the relationship of absolute myocardial blood volume (MBV) and blood flow (MBF) to global myocardial oxygen demand. A group of 27 mongrel dogs were divided into 10 controls and 17 with acute coronary stenosis. On 1.5-T MRI, first-pass perfusion imaging with a bolus injection of a blood-pool contrast agent was performed to determine myocardial perfusion both at rest and during either dipyridamole-induced vasodilation or dobutamine-induced stress. Regional values of MBF and MBV were quantified by using a fast mapping technique. Color microspheres and 99m Tc-labeled red blood cells were injected to obtain respective gold standards. Microsphere-measured MBF and 99m Tc-measured MBV reference values correlated well with the MR results. Given the same changes in MBF, changes in MBV are twofold greater with dobutamine than with dipyridamole. Under dobutamine stress, MBV shows better association with total myocardial oxygen demand than MBF. Coronary stenosis progressively reduced this association in the presence of increased stenosis severity. MR first-pass perfusion can rapidly estimate regional MBF and MBV. Absolute quantification of MBV may add additional information on stenosis severity and myocardial viability compared with standard qualitative clinical evaluations of myocardial perfusion. (orig.)

Roles of myocardial blood volume and flow in coronary artery disease: an experimental MRI study at rest and during hyperemia

Science.gov (United States)

McCommis, Kyle S.; Goldstein, Thomas A.; Abendschein, Dana R.; Misselwitz, Bernd; Pilgram, Thomas; Gropler, Robert J.

2010-01-01

Objective To validate fast perfusion mapping techniques in a setting of coronary artery stenosis, and to further assess the relationship of absolute myocardial blood volume (MBV) and blood flow (MBF) to global myocardial oxygen demand. Methods A group of 27 mongrel dogs were divided into 10 controls and 17 with acute coronary stenosis. On 1.5-T MRI, first-pass perfusion imaging with a bolus injection of a blood-pool contrast agent was performed to determine myocardial perfusion both at rest and during either dipyridamole-induced vasodilation or dobutamine-induced stress. Regional values of MBF and MBV were quantified by using a fast mapping technique. Color microspheres and 99mTc-labeled red blood cells were injected to obtain respective gold standards. Results Microsphere-measured MBF and 99mTc-measured MBV reference values correlated well with the MR results. Given the same changes in MBF, changes in MBV are twofold greater with dobutamine than with dipyridamole. Under dobutamine stress, MBV shows better association with total myocardial oxygen demand than MBF. Coronary stenosis progressively reduced this association in the presence of increased stenosis severity. Conclusions MR first-pass perfusion can rapidly estimate regional MBF and MBV. Absolute quantification of MBV may add additional information on stenosis severity and myocardial viability compared with standard qualitative clinical evaluations of myocardial perfusion. PMID:20182731

Myocardial perfusion scintigraphy with exercise and pharmacological stress

Energy Technology Data Exchange (ETDEWEB)

Sundram, F X [General Hospital of Singapore, Dept. of Nuclear Medicine (Senegal)

1996-12-31

Cardiac studies including myocardial perfusion scintigraphy was begun in the Singapore General Hospital, nuclear medicine department in 1983. From a few patients per year using planar imaging, we have in 1994 studied 1500 patients for myocardial perfusion, using mainly SPECT (single-photon emission computerised tomography) and radionuclides such as Thallium-201, Technetium-99m sestamibi and Tc-99m tetrofosmin. Patients have been stressed using treadmill exercise or pharmacological agents; we have used dipyridamole, and dobutamine for pharmacological stress but have no experience with intravenous adenosine.

Myocardial perfusion scintigraphy with exercise and pharmacological stress

International Nuclear Information System (INIS)

Sundram, F.X.

1995-01-01

Cardiac studies including myocardial perfusion scintigraphy was begun in the Singapore General Hospital, nuclear medicine department in 1983. From a few patients per year using planar imaging, we have in 1994 studied 1500 patients for myocardial perfusion, using mainly SPECT (single-photon emission computerised tomography) and radionuclides such as Thallium-201, Technetium-99m sestamibi and Tc-99m tetrofosmin. Patients have been stressed using treadmill exercise or pharmacological agents; we have used dipyridamole, and dobutamine for pharmacological stress but have no experience with intravenous adenosine

Effect of pre-analytical handling on haematological variables in minipigs

DEFF Research Database (Denmark)

Olsen, A K; Bladbjerg, E-M; Jensen, A L

2001-01-01

Pre-analytical handling may be an important determinant of haematological variables, if analysis is delayed. We investigated the effect of anticoagulants, i.e. tripotassium ethylenediamine-tetraacetic acid (EDTA) and citric acid, theophylline, adenosine, dipyridamole (CTAD), storage time (0.5, 1......, the samples must be stored in a refrigerator until analysis. Our studies underline that time delay before analysis of haematological variables can cause increased variation, and should therefore be limited as far as possible in order to reduce the number of animals needed to make reliable conclusions...

Surgery of abdominal aortic aneurysm associated with coronary artery disease. Simultaneous or two staged operation

International Nuclear Information System (INIS)

Tanaka, Hiroyuki; Narisawa, Takashi; Mori, Takanobu; Masuda, Mikio; Kishi, Daijirou; Suzuki, Takashi; Takaba, Toshihiro

2003-01-01

Coronary artery disease (CAD) was evaluated by noninvasive examination in abdominal aortic aneurysm (AAA) patients. A simultaneous operation or a 2-staged operation was performed depending on the seriousness of the condition when both diseases were combined. A total of 36 patients underwent elective repair of AAA between 1996 and 2001. Coronary angiography (CAG) was performed only in patients with suspected CAD by dipyridamole myocardial scintigraphy. Significant CAD was found in 8 patients. Simultaneous operation was performed in 4 patients, and off-pump coronary artery bypass grafting (OPCAB) was performed in all cases of simultaneous operation. In 4 patients receiving 2-staged operations, 1 standard coronary artery bypass grafting (CABG), 1 OPCAB and 2 percutaneous transluminal coronary angioplasties (PTCA) were performed prior to AAA surgery. Twenty-eight patients underwent only AAA operation. Though there were no incidents of perioperative myocardial infarction or cardiac related deaths in this group, 2 patients died due to other causes (hemorrhage and duodenal perforation). In the 8 patients associated with CAD, 1 patient died of myonephrotic metabolic syndrome (MNMS) after simultaneous operation. The other 7 patients revived their social function soon of the discharge. Dipyridamole cardiac scintigraphy was considered to be an effective examination for evaluation of CAD in AAA patients. There was no need to perform CAG in all AAA patients. The policy of choosing simultaneous operation or 2-staged operation according to the seriousness of the 2 diseases seemed to be appropriate. (author)

Prevention of cardiac complications in peripheral vascular surgery

International Nuclear Information System (INIS)

Cutler, B.S.

1986-01-01

The prevalence of severe coronary artery disease in peripheral vascular patients exceeds 50 per cent. Complications of coronary artery disease are the most common causes of mortality following peripheral vascular operations. To reduce the incidence of cardiac complications, it is first necessary to identify patients at risk through screening tests. Screening methods in current use include risk factor analysis, exercise testing, routine coronary angiography, and dipyridamole thallium-201 scintigraphy. The risk factor approach has the advantage of being widely applicable since it makes use of historical, physical, and electrocardiographic findings that are already familiar to surgeons and anesthesiologists. It is also inexpensive. However, it may overlook the patient who has no symptoms of coronary artery disease, possibly as a result of the sedentary lifestyle imposed by complications of peripheral vascular disease. The electrocardiographically monitored stress test will identify the asymptomatic patient with occult coronary disease and is helpful in predicting operative risk. However, a meaningful test is dependent on the patient's ability to exercise--an activity that is frequently limited by claudication, amputation, or arthritis. Exercise testing also suffers from a lack of sensitivity and specificity when compared with coronary arteriography. Routine preoperative coronary angiography overcomes the exercise limitation of treadmill testing but is not widely applicable as a screening test for reasons of cost and inherent risk. Dipyridamole thallium-201 scanning, on the other hand, is safe and of relatively low cost and does not require exercise

A stability-study of expired ampoules manufactured more than 40 years ago.

Science.gov (United States)

Zilker, Markus; Sörgel, Fritz; Holzgrabe, Ulrike

2018-02-20

Pharmaceutical manufacturers have to study the stability of drug products before marketing according to ICH guideline Q1A(R2); data of those investigations aim to set expiry dates. The expiry date on the container of a remedy assures the physician and the patient a stability of the drug in its formulation i.e. within a specification of 95-105%. Only few studies show that shelf-lives of pharmaceutical products are often longer than expiration dates. The objective of the study presented here was determining the content of nine expired ampoules manufactured in the last century and identifying the impurity profile by means of HPLC-UV and HPLC-MS, respectively. The ampoules are part of the "PEAK-collection" of long expired finished pharmaceutical products at IBMP, Nürnberg-Heroldsberg, and consists among others of epinephrine (Suprarenin and Adrenalin in Oil), etilefrine (Effortil ® ), synephrine (Sympatol ® ), caffeine and procaine (Impletol), caffeine and sodium salicylate (Caffeinum Salicylicum), dipyridamole (Persantin ® ), furosemide (Lasix ® ), and metamizole (Novalgin ® ). For chromatographic investigations methods of the European Pharmacopoeia for related substances were used; for determining the content, they were validated for linearity, precision, and accuracy. The results were compared to current reference ampoules. Five out of nine ampoules were still within the specified content limits. In Suprarenin and Adrenalin in Oil, both containing epinephrine, Impletol (procaine), and Persantin ® (dipyridamole) contents were decreased to 70%, 74%, 79%, and 86%, respectively, and therefore out of specification. Copyright © 2017 Elsevier B.V. All rights reserved.

Myocardial ischemia in Kawasaki disease

International Nuclear Information System (INIS)

Fukuda, Tsuyoshi

1993-01-01

The detection of myocardial ischemia is essential for evaluation of patients with Kawasaki disease, especially who have had coronary artery lesions. To evaluate the clinical efficacy of Tl-201 single photon emission computed tomography (SPECT) after dipyridamole infusion (maximum dose 0.70 mg/kg) for detecting myocardial ischemia, 44 patients with Kawasaki disease aged 7.7±4.8 years at the study and 10 age matched controls were observed. In the Kawasaki disease group, significant coronary artery stenosis was observed in 14, coronary aneurysm without stenosis in 18, the regression of the coronary aneurysms in 2 and without coronary lesions in 10 patients. In 24 of 44 patients, treadmill exercise stress test was also performed at the same period. Myocardial ischemic changes were observed in 11 patients, all combined with significant coronary artery stenosis. The sensitivity of SPECT for detection of overall coronary stenosis was 79%, coronary that of treadmill exercise test was only 33% (p<0.001). Furthermore, among the patients having significant coronary stenosis, the severity score was significantly elevated in patients who had electrocardiographic abnormal Q wave compared to those without abnormal Q wave (51.0±38.8 versus 20.0±12.1, p<0.05). These data suggest that the pharmacological stress scintigraphy using dipyridamole injection provides not only the accurate detection but quantitative evaluation of myocardial ischemia in these patients. This noninvasive technique may become one of the most useful index for detection and follow-up of myocardial ischemia in Kawasaki disease. (author)

SPECT Myocardial Blood Flow Quantitation Concludes Equivocal Myocardial Perfusion SPECT Studies to Increase Diagnostic Benefits.

Science.gov (United States)

Chen, Lung-Ching; Lin, Chih-Yuan; Chen, Ing-Jou; Ku, Chi-Tai; Chen, Yen-Kung; Hsu, Bailing

2016-01-01

Recently, myocardial blood flow quantitation with dynamic SPECT/CT has been reported to enhance the detection of coronary artery disease in human. This advance has created important clinical applications to coronary artery disease diagnosis and management for areas where myocardial perfusion PET tracers are not available. We present 2 clinical cases that undergone a combined test of 1-day rest/dipyridamole-stress dynamic SPECT and ECG-gated myocardial perfusion SPECT scans using an integrated imaging protocol and demonstrate that flow parameters are capable to conclude equivocal myocardial perfusion SPECT studies, therefore increasing diagnostic benefits to add value in making clinical decisions.

Transthoracic Doppler echocardiography compared with positron emission tomography for assessment of coronary microvascular dysfunction

DEFF Research Database (Denmark)

Michelsen, Marie Mide; Mygind, Naja Dam; Pena, Adam

2017-01-01

stenosis at invasive coronary angiography, TTDE CFVR by dipyridamole induced stress and MBFR by rubidium-82 PET with adenosine was successfully measured in 107 subjects. Repeatability of TTDE CFVR was assessed in 10 symptomatic women and in 10 healthy individuals. RESULTS: MBFR was systematically higher...... by time-interval between examinations. Results were similar when adjusting for rate pressure product or focusing on perfusion of the left anterior descending artery region. Limits of agreement (CI) for repeated CFVR in 10 healthy individuals and in 10 women with angina was 0.44 (0.21;0.68) and 0.48 (0...

Biphasic thallium 201 SPECT-imaging for the noninvasive diagnosis of myocardial perfusion abnormalities in a child with Kawasaki disease--a case report

International Nuclear Information System (INIS)

Hausdorf, G.; Nienaber, C.A.; Spielman, R.P.

1988-01-01

The mucocutaneous lymph node syndrome (Kawasaki disease) is of increasing importance for the pediatric cardiologist, for coronary aneurysms with the potential of thrombosis and subsequent stenosis can develop in the course of the disease. The authors report a 2 1/2-year-old female child in whom, fourteen months after the acute phase of Kawasaki disease, myocardial infarction occurred. Biphasic thallium 201 SPECT-imaging using dipyridamole depicted anterior wall ischemia and inferolateral infarction. This case demonstrates that noninvasive vasodilation-redistribution thallium 201 SPECT-imaging has the potential to predict reversible myocardial perfusion defects and myocardial necrosis, even in small infants with Kawasaki disease

Comparaison de différentes associations d'anticoagulants sur les numérations plaquettaires et la formation d'agrégats chez le chat

OpenAIRE

Charru, Pauline

2011-01-01

Chez le chat, l'hémogramme est un examen complémentaire parfois difficile à interpréter aux vues des nombreuses difficultés d'ordre pré-analytique et analytique potentielle. Parmi elles, on retiendra la forte tendance des plaquettes à s'agréger in vitro, surtout sur EDTA-dépendante, une nouvelle molécule antiagrégante a montré son intérêt : le CTAD (Citrate, Théophylline, Adénosine et Dipyridamole). Dans notre étude, l'utilisation de l'association EDTA et CTAD chez 46 chats sains, en éliminan...

Estimation of coronary flow reserve by sestamibi imaging in patients with mild hypertension and normal coronary arteries

International Nuclear Information System (INIS)

Storto, G.; Gallicchio, R.; Maddalena, F.; Pellegrino, T.; Petretta, M.; Fiumara, G.; Cuocolo, A.

2015-01-01

Patients with hypertension may exhibit abnormal vasodilator capacity during pharmacological vasodilatation. We assessed coronary flow reserve (CFR) by sestamibi imaging in hypertensive patients with normal coronary vessels. Twenty-five patients with untreated mild essential hypertension and normal coronary vessels and 10 control subjects underwent dipyridamole-rest Tc-99m sestamibi imaging. Myocardial blood flow (MBF) was estimated by measuring first transit counts in pulmonary artery and myocardial counts from tomograhic images. CFR was expressed as the ratio of stress to rest MBF. Coronary vascular resistances (CVR) were computed as the ratio between mean arterial pressure and MBF. Estimated MBF at rest was not different in patients and controls (1.11±0.59 vs. 1.14±0.28 counts/pixel/s; P=0.87). Conversely, stress MBF was lower in patients than in controls (1.55±0.47 vs. 2.68±0.53 counts/pixel/s; P<0.001). Thus, CFR was reduced in patients compared to controls (1.61±0.58 vs. 2.43±0.62; P<0.001). Rest and stress CVR values were higher in patients (P<0.001), while stress-induced changes in CVR were not different (P=0.08) between patients (-51%) and controls (-62%). In the overall study population, a significant relation between CFR and stress-induced changes in CVR was observed (r=-0.86; P<0.001). Sestamibi imaging may detect impaired coronary vascular function in response to dipyridamole in patients with untreated mild essential hypertension and normal coronary arteries. A mild increase in arterial blood pressure does not affect baseline MBF, but impairs coronary reserve due to the amplified resting coronary resistances.

Chronotropic response to vasodilator-stress in patients submitted to myocardial perfusion imaging: impact on the accuracy in detecting coronary stenosis

International Nuclear Information System (INIS)

Gimelli, Alessia; Coceani, Michele; Quaranta, Angela; Emdin, Michele; Liga, Riccardo; Marzullo, Paolo

2015-01-01

A lower heart rate response (HRR) during vasodilator MPI has been shown to have a relevant adverse prognostic impact. We sought to evaluate the interaction among individual HRR to vasodilator stress and myocardial perfusion imaging (MPI) accuracy in patients with suspected ischemic heart disease (IHD). One hundred and sixty-five consecutive patients were submitted to vasodilator-stress MPI on a cardiac camera equipped with cadmium-zinc-thelluride detectors and coronary angiography. A coronary stenosis >70 % was considered significant. In every patient, the summed difference score (SDS) was computed from MPI images. Patients were categorized according to the tertiles of the distribution of individual HRR during dipyridamole: ''Group 1'' (HRR < 8 bpm; lowest tertile); ''Group 2'' (8 ≤ HRR ≤ 12 bpm; middle tertile); ''Group 3'' (HRR >12 bpm; highest tertile). Significant coronary artery disease (CAD) was present in 102 (62 %) patients. In the overall population, MPI showed a significant accuracy (AUC: 0.81, 95 % CI 0.74-0.86; p < 0.001) in unmasking the presence of significant coronary stenosis. Interestingly, in patients with a blunted HRR during dipyridamole (''Group 1'') MPI showed a significantly lower sensitivity (68 %) in detecting CAD than in those with a higher HRR (''Group 3'') (91 %, p = 0.007), despite a preserved specificity (76 % vs 77 %, P=NS). Similarly, the correlation among CAD extent and post-stress LV functional stunning was limited to ''Group 3'' patients, while it disappeared in those with blunted HRR. In patients with suspected IHD, MPI sensitivity is strongly influenced by the magnitude of patient heart rate increase to the pharmacologic stressor, suggesting an interaction among blunted HRR and lower accuracy in unmasking CAD. (orig.)

Pressure-volume Relationship in the Stress-echocardiography Laboratory: Does (Left Ventricular End-diastolic) Size Matter?

Science.gov (United States)

Bombardini, Tonino; Mulieri, Louis A; Salvadori, Stefano; Costantino, Marco Fabio; Scali, Maria Chiara; Marzilli, Mario; Picano, Eugenio

2017-02-01

The variation between rest and peak stress end-systolic pressure-volume relation is an afterload-independent index of left ventricular contractility. Whether and to what extent it depends on end-diastolic volume remains unclear. The aim of this study was to assess the dependence of the delta rest-stress end-systolic pressure-volume relation on end-diastolic volume in patients with negative stress echo and all ranges of resting left ventricular function. We analyzed interpretable data obtained in 891 patients (593 men, age 63 ± 12 years) with ejection fraction 47% ± 12%: 338 were normal or near-normal or hypertensive; 229 patients had coronary artery disease; and 324 patients had ischemic or nonischemic dilated cardiomyopathy. They were studied with exercise (n = 172), dipyridamole (n = 482) or dobutamine (n = 237) stress echocardiography. The end-systolic pressure-volume relation was evaluated at rest and peak stress from raw measurement of systolic arterial pressure by cuff sphygmomanometer and end-systolic volume by biplane Simpson rule 2-dimensional echocardiography. Absolute values of delta rest-stress end-systolic pressure-volume relation were higher for exercise and dobutamine than for dipyridamole. In the overall population, an inverse relationship between end-systolic pressure-volume relation and end-diastolic volume was present at rest (r 2 = 0.69, P stress (r 2 = 0.56, P stress end-systolic pressure-volume relation was considered (r 2 = 0.13). Left ventricular end-diastolic volume does not affect the rest-stress changes in end-systolic pressure-volume relation in either normal or abnormal left ventricles during physical or pharmacological stress. Copyright © 2016 Sociedad Española de Cardiología. Published by Elsevier España, S.L.U. All rights reserved.

Quantitative analysis of 99Tcm-MIBI myocardial perfusion images before and after intracoronary stenting

International Nuclear Information System (INIS)

Liu Liangfu; Wang Tie; Yin Chuangui; Hu Dayi; Liu Jian; Li Xinhua; Zhang Shourong; Jia Sanqing

2001-01-01

Objective: Assessing the value of 99 Tc m -MIBI myocardial perfusion imaging (SPECT) in selection of patients for stenting, and in evaluation of the therapeutic effects of the procedure and its value for following-up of the patients with coronary artery stents. Methods: Rest and dipyridamole stress SPECT were performed in 51 patients with coronary artery diseases and coronary artery stents one week before procedure, one week and half a year (21 cases) after procedure. The location, degree and area of blood flow deficit were quantitatively analyzed. Results: Before the procedure, 50 patients showed blood flow deficit degree >80% (the lower the percentage, the more the blood flow deficit degree), blood flow deficit area 80%, 8 (16%) patients who had been with blood flow deficit area 70% before the procedure, 10 (20%) of them one week after procedure were without any severe blood flow deficit. Their acute myocardial infarctions were significantly improved. Pre-procedure, at rest, the blood flow deficit degree was 38.05%, at one week after procedure became 57.40%, it was improved by 19.35%. The patients with blood flow deficit area of 70.75% at rest before the procedure, showed a deficit area of 55.91% one week after the procedure. Compared to pre-procedure readings, the significant improvement (P 0.05) in blood flow deficit degree and area between rest and dipyridamole stress SPECT before or one week, half a year after procedure. Conclusions: The blood flow deficit degree or area measured by SPECT were improved one week and half a year after procedure. SPECT is valuable in selection of patients for the procedure and in evaluation of the effect of the therapy and it is very useful during follow-up of the patients with intracoronary stents

Relationship Between Adenosine - Induced ST Segment Depression During 99mTc-MIBI Scintigraphy and The Severity of Coronary Artery Disease

International Nuclear Information System (INIS)

Cho, Jung Ah; Choi, Jung Il; Kwak, Dong Suk

1994-01-01

Pharmacologic coronary vasodilation in conjunction with myocardial perfusion scintigraphy has become an alternative to dynamic exercise test for the diagnosis and risk stratification of coronary artery disease, especially in patients who are unable to perform adequate exercise. Dipyridamole and adenosine have been used for pharmacologic stress testing with myocardial perfusion imaging. Adenosine is a potent, coronary vasodilator with rapid onset of action, short half life, near maximal coronary vasodilation and less serious side effects. ST segment depression has been reported in about 7-15% of patients with coronary artery disease receiving dipyridamole in conjunction with myocardial perfusion imaging. The exact cause and clinical significance are not known. In order to evaluate the relationship between adenosine-induced ST segment depression during 99m Tc-MIBI myocardial perfusion scintigraphy and the severity of coronary artery disease, we performed 99m -MIBI imaging after intravenous infusion of adenosine in 120 patients with suspected coronary artery disease. Of the 120 patients, 28 also performed coronary angiography. There were 24 patients with ST segment depression during 99m Tc-MIIBI scintigraphy and 96 patients without ST segment depression. Adenosine was infused intravenously at a dose of 0.14 mg/kg per minute for 6 minutes and 99 MmTc-MIB1 was injected at 3 minute. We then compared the hemodynamic changes, side effects, scintigraphic and angiographic findings. Heart rate increased 90 ± 19 beats/minute in the group with ST depression compared with 80 ±16 beats/minute in the group without ST depression(p 9m Tc-MIBI images were abnormal in 23(96%) patients with ST segment depression and 66(69%) patients without ST segment depression(p 99m Tc-MIBI myocardial perfusion scintigraphy with intravenous adenosine is related to the severity of coronary artery disease.

Chronotropic response to vasodilator-stress in patients submitted to myocardial perfusion imaging: impact on the accuracy in detecting coronary stenosis

Energy Technology Data Exchange (ETDEWEB)

Gimelli, Alessia; Coceani, Michele; Quaranta, Angela; Emdin, Michele [Fondazione Toscana Gabriele Monasterio, Pisa (Italy); Liga, Riccardo [University Hospital of Pisa, Cardio-Thoracic and Vascular Department, Pisa (Italy); Marzullo, Paolo [Fondazione Toscana Gabriele Monasterio, Pisa (Italy); CNR, Institute of Clinical Physiology, Pisa (Italy)

2015-11-15

A lower heart rate response (HRR) during vasodilator MPI has been shown to have a relevant adverse prognostic impact. We sought to evaluate the interaction among individual HRR to vasodilator stress and myocardial perfusion imaging (MPI) accuracy in patients with suspected ischemic heart disease (IHD). One hundred and sixty-five consecutive patients were submitted to vasodilator-stress MPI on a cardiac camera equipped with cadmium-zinc-thelluride detectors and coronary angiography. A coronary stenosis >70 % was considered significant. In every patient, the summed difference score (SDS) was computed from MPI images. Patients were categorized according to the tertiles of the distribution of individual HRR during dipyridamole: ''Group 1'' (HRR < 8 bpm; lowest tertile); ''Group 2'' (8 ≤ HRR ≤ 12 bpm; middle tertile); ''Group 3'' (HRR >12 bpm; highest tertile). Significant coronary artery disease (CAD) was present in 102 (62 %) patients. In the overall population, MPI showed a significant accuracy (AUC: 0.81, 95 % CI 0.74-0.86; p < 0.001) in unmasking the presence of significant coronary stenosis. Interestingly, in patients with a blunted HRR during dipyridamole (''Group 1'') MPI showed a significantly lower sensitivity (68 %) in detecting CAD than in those with a higher HRR (''Group 3'') (91 %, p = 0.007), despite a preserved specificity (76 % vs 77 %, P=NS). Similarly, the correlation among CAD extent and post-stress LV functional stunning was limited to ''Group 3'' patients, while it disappeared in those with blunted HRR. In patients with suspected IHD, MPI sensitivity is strongly influenced by the magnitude of patient heart rate increase to the pharmacologic stressor, suggesting an interaction among blunted HRR and lower accuracy in unmasking CAD. (orig.)

The role of pharmacological stress Tc-99m sestamibi myocardial perfusion imaging in an Australian population

International Nuclear Information System (INIS)

Howarth, D.M.; Booker, J.A.; Tan, T.S.K.; Bellamy, G.R.; Hardy, D.B.; Howarth, G.C.

2003-01-01

This observational study was performed in order to assess the exercise-related incremental diagnostic accuracy of Tc-99m sestamibi myocardial perfusion imaging (MPI) in a hospital-based Australian population, and to assess the relative roles of exercise and pharmacological stress in myocardial perfusion imaging (MPI). Two hundred and eight adult patients who had both Tc-99m sestamibi myocardial perfusion imaging and coronary angiography within a median time of 16 weeks were studied. The diagnostic end-point was coronary artery lesions of ≥50% and >70% stenosis detected on angiography. Using receiver operating characteristic curve analysis, the overall diagnostic accuracy was calculated, as well as the comparative accuracies in patients who undertook various levels of exercise stress testing (n=130) and those who received pharmacological (dipyridamole) stress testing (n=78). The overall respective diagnostic accuracy of Tc-99m sestamibi MPI for the diagnosis of coronary artery disease (>70% stenosis) was 81% and 76% when using the diagnostic criterion of ≥50% stenosis. On direct comparison of perfusion defects with angiographic stenoses, the respective sensitivity and specificity for the detection of >70% stenosis in each coronary artery territory was 73% and 79%. Pharmacological MPI showed a significantly greater sensitivity for the detection of localised stenoses compared to the overall group who had exercise MPI performed. Consequently, exercise stress MPI showed significantly more false negative lesions compared to dipyridamole stress imaging (p<0.003). However, a large proportion of patients were unable to perform to adequate exercise levels in this patient sample. We conclude that Tc-99m sestamibi myocardial perfusion imaging is an accurate non-invasive test for the diagnosis of coronary artery disease. Where any doubt exists as to the patient's ability to achieve exercise levels at or above 85% of the predicted value for age and gender, pharmacological

Decreased coronary reserve in patients with hypertrophic cardiomyopathy

International Nuclear Information System (INIS)

Yamaguchi, Ryutaro

1987-01-01

To assess coronary flow reserve in patients with hypertrophic cardiomyopathy (HCM), split dose thallium-201 dipyridamole (DP) myocardial scintigraphy was performed. Subjects included 30 HCM patients with asymmetric septal hypertrophy and normal coronary angiogram, 10 hypertensive patients with left ventricular hypertrophy (posterior wall thickness ≥ 15 mm) and 13 healthy controls. Coronary reserve index (CRI) was calculated as a ratio of myocardial thallium uptake after dipyridamole (0.5 mg/kg) to the baseline value. HCM patients showed a significantly lower CRI (177 %) as compared with controls (281 %) or hypertensive patients (214 %), and 17 of them had abnormally decreased CRI below the normal range (mean-2SD of controls). These HCM patients with abnormal CRI showed significantly more frequent family histrory of HCM (71 vs 31 %), and a greater degree of systolic narrowing of the septal perforator as compared with those normal CRI. Maximal work loads were significantly lower (82 vs 106 watts) in those with abnormal CRI, 31 % developed ST depression at 80 watts. However, patients with abnormal CRI did not differ from those with normal CRI in septal and posterior wall thickness, left ventricular end-diastolic pressure, and in the degree of systolic narrowing of the left anterior descending artery. In the segmental CRI analysis, 13 HCM patients showed abnormal CRI in the septal and/or apical segments, while 8 patients presented diffuse CRI decrease, including the non-hypertrophied posterior segment. These findings indicate that 57 % of HCM patients have impaired coronary vasodilatory reserve, which may not only be a consequence of left ventricular hypertrophy, elevated left ventricular end-diastolic pressure, and systolic narrowing of the coronary artery, but may be related to small vessel coronary disease. (J.P.N.)

Magnetic Resonance Imaging Measurement of Left Ventricular Blood Flow and Coronary Flow Reserve in Patients with Chronic Heart Failure due to Coronary Artery Disease

International Nuclear Information System (INIS)

Aras, A.; Anik, Y.; Demirci, A.; Balci, N.C.; Kozdag, G.; Ural, D.; Komsuogl u, B.

2007-01-01

Background: Coronary sinus flow reflects global cardiac perfusion and has been used for the assessment of myocardial flow reserve, which is reduced in chronic heart failure (CHF). Coronary flow reserve (CFR) can be measured by using phase-contrast (PC) velocity-encoded cine (VEC) magnetic resonance imaging (MRI). Purpose: To quantify and compare global left ventricular (LV) perfusion and CFR in patients with CHF and in a healthy control group by measuring coronary sinus flow with PC VEC MRI, and to correlate this with global LV perfusion, segmental first-pass perfusion, and viability in the same patients. Material and Methods: Cardiac MRI was performed in 20 patients with CHF of ischemic origin and in a control group of healthy subjects (n 11) at rest and after pharmacological stress induced by i.v. dipyridamole. The MRI protocol included cine MRI, VEC MRI, first-pass perfusion, and delayed contrast-enhanced MRI for viability. Global LV perfusion was quantified by measuring coronary sinus flow on VEC MRI at rest in all subjects. CFR was determined as the ratio of global LV perfusion before and after pharmacologic stress. Results: At rest, global LV perfusion was not significantly different in patients with CHF and the control group. After administration of dipyridamole, global LV perfusion and CFR were significantly lower in patients with CHF compared to the control group (P<0.001). An inverse correlation was observed between CFR and the number of infarcted and/or ischemic segments (P = 0.083, P 0.037). Conclusion: A combined cardiac MRI protocol including function and perfusion techniques together with VEC MRI can be used to evaluate global LV perfusion and CFR in patients with CHF. Global LV perfusion and CFR measurements may have potential in the monitoring of CHF. Impaired CFR may contribute to progressive decline in LV function in patients with CHF

Magnetic Resonance Imaging Measurement of Left Ventricular Blood Flow and Coronary Flow Reserve in Patients with Chronic Heart Failure due to Coronary Artery Disease

Energy Technology Data Exchange (ETDEWEB)

Aras, A.; Anik, Y.; Demirci, A.; Balci, N.C.; Kozdag, G.; Ural, D.; Komsuoglu, B. (Radiology Dept. and Cardiology Dept., Kocaeli Univ. School of Medicine, Kocaeli (Turkey))

2007-11-15

Background: Coronary sinus flow reflects global cardiac perfusion and has been used for the assessment of myocardial flow reserve, which is reduced in chronic heart failure (CHF). Coronary flow reserve (CFR) can be measured by using phase-contrast (PC) velocity-encoded cine (VEC) magnetic resonance imaging (MRI). Purpose: To quantify and compare global left ventricular (LV) perfusion and CFR in patients with CHF and in a healthy control group by measuring coronary sinus flow with PC VEC MRI, and to correlate this with global LV perfusion, segmental first-pass perfusion, and viability in the same patients. Material and Methods: Cardiac MRI was performed in 20 patients with CHF of ischemic origin and in a control group of healthy subjects (n 11) at rest and after pharmacological stress induced by i.v. dipyridamole. The MRI protocol included cine MRI, VEC MRI, first-pass perfusion, and delayed contrast-enhanced MRI for viability. Global LV perfusion was quantified by measuring coronary sinus flow on VEC MRI at rest in all subjects. CFR was determined as the ratio of global LV perfusion before and after pharmacologic stress. Results: At rest, global LV perfusion was not significantly different in patients with CHF and the control group. After administration of dipyridamole, global LV perfusion and CFR were significantly lower in patients with CHF compared to the control group (P<0.001). An inverse correlation was observed between CFR and the number of infarcted and/or ischemic segments (P = 0.083, P = 0.037). Conclusion: A combined cardiac MRI protocol including function and perfusion techniques together with VEC MRI can be used to evaluate global LV perfusion and CFR in patients with CHF. Global LV perfusion and CFR measurements may have potential in the monitoring of CHF. Impaired CFR may contribute to progressive decline in LV function in patients with CHF

The clinician's guide to diagnostic imaging: Cost effective pathways

International Nuclear Information System (INIS)

Grossman, Z.D.; Chew, F.S.; Ellis, D.A.; Brigham, S.C.

1987-01-01

This book presents logical, step-by-step imaging sequences for 47 medical, surgical, and pediatric problems. Topics considered include breast cancer screening, acute spinal trauma, search for primary cancer of unknown origin, acute anuria, blunt chest trauma, new onset seizures, and spinal cord compression from metastases. Other chapters have been rewritten to enhance the clarity of presentation and to incorporate new techniques such as magnetic resonance imaging, dipyridamole stress testing, and single photon emission computed tomography. The book highlights the expanding role of CT in evaluation of thoracic and abdominal problems, the emergence of magnetic resonance imaging as a vital diagnostic tool for the central nervous system, and the clinical utility of many newly developed radiopharmaceuticals

The influence of four different anticoagulants on dynamic light scattering of platelets.

Science.gov (United States)

Raczat, T; Kraemer, L; Gall, C; Weiss, D R; Eckstein, R; Ringwald, J

2014-08-01

For testing of dynamic light scattering of platelets with ThromboLUX (TLX) in platelet-rich plasma (PRP) derived from venous whole blood (vWB), anticoagulation is needed. We compared TLX score in PRPs containing citrate, ethylene-diamine-tetraacetic-acid (EDTA), citrate-phosphate-dextrose-adenine (CPDA) or citrate-theophylline-adenosine-dipyridamole. Initial and late TLX scores were measured after 30-120 min or four to six hours, respectively. Compared with citrate, mean differences in initial TLX score were only significant for CPDA. Also, mean differences between initial and late TLX scores were only significant for CPDA. TLX failed to detect EDTA-induced platelet alterations. The clinical relevance of TLX needs further studies. © 2014 International Society of Blood Transfusion.

Comparison of exercise and pharmacologic stress in myocardium perfusion imaging for CHD

International Nuclear Information System (INIS)

Li Zebo; Zheng Kangni; Cheng Xiaorui; Liu Hui; Cheng Yihai

1995-01-01

In order to provide a proper stress test, exercise, dipyridamole and ATP stress were compared. Three modalities were compared with respect to the detecting rate, methodology, hemodynamic and side effects. There are no significant differences in their ability of detecting coronary heart disease (CHD) (P>0.05). Exercise stress causes an increase in heart rate, blood pressure and myocardium oxygen consumption. Pharmacologic stress cause a slight increase in heart rate, but a decrease in blood pressure (P<0.01). Exercise stress is a basic method with good image quality, but it needs a special equipment. Pharmacologic stress is an easier, cheaper and safer method, particularly useful for patients unable to perform exercise test

Dipyridamole-thallium-201 tomography documenting improved myocardial perfusion with therapy in Kawasaki disease

International Nuclear Information System (INIS)

Nienaber, C.A.; Spielmann, R.P.; Hausdorf, G.

1988-01-01

Thallium-201 tomographic perfusion studies after pharmacologic vasodilation were performed in seven children (aged 2 years 8 months to 8 years 7 months), 3 to 20 months after the acute stage of the disease. In all patients coronary aneurysms were seen on cross-sectional echocardiograms. The scintigrams of six children showed no significant regional reduction of myocardial thallium-201 uptake. These children had remained asymptomatic in the follow-up period after the acute inflammatory stage of Kawasaki disease. Persistent and transient thallium defects were present in one child with acute posterolateral myocardial infarction; obstruction of two coronary vessels supplying the defect zones was confirmed by contrast angiography. After 8 months of treatment a follow-up nuclear scan showed marked reduction in the size of the defect and almost complete abolishment of the ischemic reaction. Thus tomographic thallium-201 perfusion scintigraphy in conjunction with vasodilation stress is useful to assess myocardial perfusion in children with Kawasaki disease and demonstrates marked improvement in regional perfusion after adequate medical therapy

In vivo labelling in several rat tissues of 'peripheral type' benzodiazepine binding sites

Energy Technology Data Exchange (ETDEWEB)

Benavides, J.; Guilloux, F.; Rufat, P.; Uzan, A.; Renault, C.; Dubroeucq, M.C.; Gueremy, C.; Le Fur, G. (Pharmuka Laboratoires, 92 - Gennevilliers (France))

1984-03-16

'Peripheral type' benzodiazepine binding sites in several rat tissues were labelled by intravenous injection of (/sup 3/H)PK 11195 and (/sup 3/H)RO5-4864. Binding was saturable in all tissues studied and regional distribution paralleled the in vitro binding. A similar potency order of displacing compounds was found in vivo and in vitro PK 11195 > PK 11211 > RO5-4864 > diazepam > dipyridamole > clonazepam. These results demonstrate the feasibility of using this technique to examine the effects of pharmacological manipulation on the binding sites in their native state. However, some properties (broader maximum during time course, higher percentage of particulate binding in the brain and independence of temperature) make (/sup 3/H)PK 11195 the most suitable ligand for this kind of studies.

Critical myocardial perfusion in hypertrophic cardiomyopathy demonstrated with thallium-201 SPECT with a quantitative bullseye map

International Nuclear Information System (INIS)

Hunter, G.J.

1990-01-01

PURPOSE: A particular problem in hypertrophic cardiomyopathy (HCM) is the need to distinguish between true and apparent ischemia in otherwise normal areas of muscle when these are compared with adjacent hypertrophic muscle. The authors of this paper studied patients with proved HCM to define patterns of perfusion. T1-201 single photon emission CT (SPECT) was performed in 83 HCM patients immediately after stress (dipyridamole, 0.5 mg/kg) and 3 hours later for the redistribution image. The data were analyzed by a normalized quantitative analysis using a local bulls-eye technique. In all patients, the pattern of tracer distribution was different from expected uptake in a normal population. By virtue of the increased microcirculation to hypertrophied muscle, adjacent normal muscle appeared relatively ischemic

Clinical application of bull's eye map in 201Tl myocardial tomography for the diagnosis of coronary artery disease

International Nuclear Information System (INIS)

Liu Yongchang

1991-01-01

Bull's eye map in thallium-201 myocardial tomography was performed in 50 patients, and compared with planar imaging. In 27 rest imaging, 6 AMI were abnormal both in plannar and bull's eye images, in 10 OMI, planar abnormal in 6 and doubtful in 4, while bull's eye abnormal in 8 and doubtful in 2; in 11 angina, planar abnormal in 2, doubtful in 5 and normal in 4; but bull's eye abnormal in 5, doubtful abnormal in 4 and normal in 2. In 3 cases of dipyridamole imaging 2 angina were positive, 1 hypertension was negetive, while bull's eye map were all positive. It was demonstrated that bull's eye map gives a direct and clean view and also easy for the anatomical localization of the hypoperfused area

Myocardial perfusion scintigraphy in Germany in 2009: utilization and state of the practice

Energy Technology Data Exchange (ETDEWEB)

Lindner, Oliver; Burchert, Wolfgang [University Hospital of the Ruhr University Bochum, Institute of Radiology, Nuclear Medicine and Molecular Imaging, Heart and Diabetes Centre North Rhine-Westphalia, Bad Oeynhausen (Germany); Bengel, Frank M. [Hanover University School of Medicine, Department of Nuclear Medicine, Hannover (Germany); Zimmermann, Rainer [Klinikum Pforzheim GmbH, Cardiology Department, Pforzheim (Germany); Dahl, Juergen vom [Kliniken Maria Hilf GmbH, Cardiology Department, Moenchengladbach (Germany); Schaefers, Michael [Westfaelische Wilhelms Universitaet Muenster, European Institute of Molecular Imaging, Muenster (Germany)

2011-08-15

Since 2006, the working group Cardiovascular Nuclear Medicine of the German Society of Nuclear Medicine, in cooperation with the working group Nuclear Cardiology of the German Cardiac Society, has been surveying the utilization and technical realization of myocardial perfusion scintigraphy (MPS) in Germany. This paper presents the results of the reporting year 2009. A total of 291 centres participated in the inquiry, including 179 private practices (PP), 86 hospitals (HO) and 26 university hospitals (UH). MPS of 98,103 patients were reported. The MPS numbers per million population (pmp) were estimated at 2,360; 76% of the MPS were performed in PP, 17% in HO and 7% in UH. The ratio of MPS to coronary angiography to revascularization was 0.5 to 2.3 to 1. Data from 134 centres which participated in the surveys from 2005 to 2009 showed a decrease in MPS utilization of 2.2%. Nearly half of the MPS were requested by ambulatory care cardiologists. Of all MPS studies, 89% were conducted with {sup 99m}Tc perfusion tracers. Ergometry was the preferred stress test (69%). Adenosine was used in 16%, adenosine + exercise in 7%, dipyridamole in 3%, dipyridamole + exercise in 5% and dobutamine in <1%. Gated single proton emission computed tomography (SPECT) acquisition was performed in 56% of all rest MPS and in 56% of all stress MPS. Both rest and stress MPS were ECG gated in 41%. Only 33% of the centres always performed a quantification of the perfusion studies, whereas 51% did not apply any quantification; 4% of the MPS studies were corrected for attenuation, and 17 centres used transmission sources of 12 CT-based systems. A scan activity of 2,380 MPS pmp is in the upper third of the European range. The ratios to coronary angiography and to revascularization suggest that angiography dominates diagnosis and management of coronary artery disease (CAD). The clinical and technical realizations reveal that the predominant goals of further trainings to optimize MPS are in the field

Age- and gender-specific differences in left ventricular cardiac function and volumes determined by gated SPET

International Nuclear Information System (INIS)

Bondt, P. de; Wiele, C. van de; Winter, F. de; Dierckx, R.A.; Sutter, J. de; Backer, G. de

2001-01-01

The aim of this study was to determine normative volumetric data and ejection fraction values derived from gated myocardial single-photon emission tomography (SPET) using the commercially available software algorithm QGS (quantitative gated SPET). From a prospective database of 876 consecutive patients who were referred for a 2-day stress-rest technetium-99m tetrofosmin (925 MBq) gated SPET study, 102 patients (43 men, 59 women) with a low (<10%) pre-test likelihood of coronary disease were included (mean age 57.6 years). For stress imaging, a bicycle protocol was used in 79 of the patients and a dipyridamole protocol in 23. Left ventricular ejection fraction (LVEF) and end-diastolic and -systolic volumes (EDV and ESV) were calculated by QGS. EDV and ESV were corrected for body surface area, indicated by EDVi and ESVi. To allow comparison with previous reports using other imaging modalities, men and women were divided into three age groups (<45 years, ≥45 years but <65 years and ≥65 years). Men showed significantly higher EDVi and ESVi values throughout and lower LVEF values when compared with women in the subgroup ≥65 years (P<0.05, ANOVA). Significant negative and positive correlations were found between age and EDVi and ESVi values for both women and men and between LVEF and age in women (Pearson P≤0.01). LVEF values at bicycle stress were significantly higher than at rest (P=0.000, paired t test), which was the result of a significant decrease in ESV (P=0.003), a phenomenon which did not occur following dipyridamole stress (P=0.409). The data presented suggest that LVEF and EDVi and ESVi as assessed by QGS are strongly gender-specific. Although the physiological significance of these results is uncertain and needs further study, these findings demonstrate that the evaluation of cardiac function and volumes of patients by means of QGS should consider age- and gender-matched normative values. (orig.)

Optimization of flow reserve measurement using SPECT technology to evaluate the determinants of coronary microvascular dysfunction in diabetes

Energy Technology Data Exchange (ETDEWEB)

Marini, Cecilia [CNR Institute of Bioimages and Molecular Physiology, Milan, Section of Genoa (Italy); Bezante, GianPaolo; Modonesi, Elisa; Rollando, Daniela; Balbi, Manrico; Brunelli, Claudio [University of Genoa, Department of Internal Medicine, Cardiology, Genoa (Italy); Gandolfo, Patrizia; Morbelli, Silvia D.; Armonino, Riccardo [University of Genoa, Department of Internal Medicine, Nuclear Medicine, Genoa (Italy); DePascale, Angelo; Maggi, Davide; Albertelli, Manuela; Cordera, Renzo [University of Genoa, Department of Endocrinological Metabolic Sciences, Diabetology, Genoa (Italy); Sambuceti, Gianmario [University of Genoa, Department of Internal Medicine, Nuclear Medicine, Genoa (Italy); Advanced Biotechnology Center, Genoa (Italy)

2010-02-15

The aim of this study was to validate a new method to measure regional myocardial perfusion reserve (MPR) with technetium-labelled tracers in patients with type 2 diabetes mellitus (DM2). A total of 40 consecutive DM2 patients without history of coronary artery disease (CAD) and 7 control subjects were recruited. Dipyridamole myocardial blood flow index (MBF) was assessed by measuring first transit counts in the pulmonary artery and myocardial count rate from gated SPECT images using {sup 99m}Tc-labelled tracers. The corresponding MBF index was estimated 2 h later according to the same procedure. Regional myocardial perfusion reserve (MPR) was defined as the ratio between dipyridamole and baseline MBF using a 17-segment left ventricular (LV) model. Coronary flow reserve (CFR) was estimated by transthoracic contrast echo Doppler monitoring of flow velocity in the left anterior descending coronary artery (LAD) during the same session. Estimated MPR was higher in control subjects than in patients (3.36 {+-} 0.66 vs 1.91 {+-} 0.61, respectively, p < 0.01). In patients, LAD CFR and LAD MPR were 2.01 {+-} 0.78 vs 1.93 {+-} 0.63, respectively (p = ns). The agreement between the two techniques was documented by their close correlation (r = 0.92, p < 0.001) and confirmed by the Bland-Altman analysis. Reversible perfusion defects occurred in 13 patients (32%) who showed similar MPR values as the remaining 27 (2.10 {+-} 0.71 vs 1.83 {+-} 0.71, respectively, p = ns). Finally, MPR was closely correlated with age (r = -0.50, p < 0.01) and time elapsed from the diagnosis of DM2 (r = -0.51, p < 0.01). LV regional MPR can be accurately estimated with the broadly available single photon technology. Application of this method to DM2 patients documents the presence of a microvascular dysfunction homogeneously distributed throughout the LV walls and most frequently not associated with reversible perfusion defects. (orig.)

Variability and reproducibility of rubidium-82 kinetic parameters in the myocardium of the anesthetized canine

International Nuclear Information System (INIS)

Coxson, P.G.; Brennan, K.M.; Huesman, R.H.

1995-01-01

Kinetic analysis of 82 Rb (I) dynamic PET data produces quantitative measures which could be used to evaluate ischemic heart disease. These measures have the potential to generate objective comparisons of different patients or the same patient at different times. To achieve this potential, it is essential to determine the variability and reproducibility of the kinetic parameters. A total of 48 I dynamic PET datasets were acquired from two pure bred beagles. Each animal underwent eight I PET studies with essentially the same protocol for three successive weeks. Data were acquired with the Donner 600-Crystal Positron Tomograph (PET600). In each week, single-slice dynamic I PET datasets were collected with the animal at rest at three different gantry positions separated by 5 mm. Additional dataset were collected after dipyridamole infusion and after administration of aminophylline to induce a return to rest. A two-compartment kinetic model with correction for myocardial vasculature and spillover from the left ventricular blood pool was used to analyze the dynamic datasets. Model parameters for uptake (k 1 ), washout (k 2 ) and vascular fraction (f v ) were estimated in 11-14 myocardial regions of interest (ROIs) using a weighted least-squares criterion. Statistical fluctuation due to the PET acquisition process was minimized by using a relatively high I dose (about 30 mCi) to take advantage of the high count rate capacity of the PET600. The variation in mean k 1 , where the mean is taken over the myocardial ROIs was 10%-20% (Dog 1) and 15%-50% (Dog 2) among the rest studies conducted on the same data. Similar variation was evident in comparing studies in the same animal for different weeks. Spatial and temporal variation in estimates of the uptake rate (k 1 ) of I in the resting myocardium of the anesthetized canine are small in relation to the functional increase in k 1 , following dipyridamole stress. 17 refs., 14 figs

Radiation exposure for medical staff performing quantitative coronary perfusion PET with 13N-ammonia

DEFF Research Database (Denmark)

Kristoffersen, Ulrik Sloth; Borgwardt, Henrik Gutte; Skovgaard, Dorthe Charlotte

2009-01-01

with dipyridamole) and eight examinations consisted of three PET scans (additionally a scan after cold pressor testing). The two nuclear technologists and the physician attending the examinations were equipped with an electronic dosemeter over the chest and thermoluminescent dosimetry chips on the right index...... finger and wrist. RESULTS: The highest mean equivalent dose per examination for a staff member was 453 microSv (417-490 microSv) to the right index finger, 138 microSv (127-149 microSv) to the right wrist and 13 +/- 0.8 microSv to the chest. CONCLUSIONS: Myocardial perfusion PET with (13)N......-ammonia exposes the staff to radiation doses that are comparable to doses from (18)F-fluoro-deoxy-glucose scans and the annual doses are well within the recommended upper limits for radiation workers....

Safety and efficacy of intensive vs. guideline antiplatelet therapy in high-risk patients with recent ischemic stroke or transient ischemic attack

DEFF Research Database (Denmark)

Christensen, Hanne Krarup

2015-01-01

RATIONALE: The risk of recurrence following a stroke or transient ischemic attack is high, especially immediately after the event. HYPOTHESIS: Because two antiplatelet agents are superior to one in patients with non-cardioembolic events, more intensive treatment might be even more effective. SAMPLE...... SIZE ESTIMATES: The sample size of 4100 patients will allow a shift to less recurrence, and less severe recurrence, to be detected (odds ratio 0·68) with 90% power at 5% significance. METHODS AND DESIGN: Triple Antiplatelets for Reducing Dependency after Ischaemic Stroke (ISRCTN47823388) is comparing...... the safety and efficacy of intensive (combined aspirin, clopidogrel, and dipyridamole) vs. guideline antiplatelet therapy, both given for one-month. This international collaborative parallel-group prospective randomized open-label blinded-end-point phase III trial plans to recruit 4100 patients with acute...

Variability of insulin-stimulated myocardial glucose uptake in healthy elderly subjects

DEFF Research Database (Denmark)

Kofoed, Klaus F; Hove, Jens D; Freiberg, Jacob

2002-01-01

The aim of this study was to assess regional and global variability of insulin-stimulated myocardial glucose uptake in healthy elderly subjects and to evaluate potentially responsible factors. Twenty men with a mean age of 64 years, no history of cardiovascular disease, and normal blood pressure...... rest and hyperaemic blood flow during dipyridamole infusion were measured with nitrogen-13 ammonia and positron emission tomography in 16 left ventricular myocardial segments. Intra-individual and inter-individual variability of insulin-stimulated myocardial glucose uptake [relative dispersion...... = (standard deviation/mean)] was 13% and 29% respectively. Although inter-individual variability of glucose uptake and blood flow at rest was of the same magnitude, no correlation was found between these measures. Regional and global insulin-stimulated myocardial glucose uptake correlated linearly with whole...

Evaluation in dogs of a new double-dose technique for imaging changes in myocardial perfusion

International Nuclear Information System (INIS)

Rothendler, J.A.; Okada, R.D.; Strauss, H.W.; Chesler, D.A.; Pohost, G.M.

1984-01-01

Assessment of myocardial perfusion with thallium immediately before and after an intervention that alters blood flow has been difficult due to presence of residual activity from the first tracer dose at the time of the second imaging. In a canine model the authors investigated a technique using two separate thallium injections during an intervention and after its reversal. Images were obtained after each injection, and a difference image was obtained by subtracting the first from the second image to correct for tracer persisting from the first injection. Interventions on coronary blood flow included: transient occlusion, subcritical stenosis with dipyridamole infusion, and permanent occlusion. The first images showed defects corresponding to the occlusion or stenosis, while the ''difference'' images correlated with myocardial perfusion at the time of the second injection

Effects of drugs on platelet function.

Science.gov (United States)

Morse, E E

1977-01-01

Numerous drugs and chemicals affect the function of human blood platelets. The mechanism of action of some medications is partly understood. Aspirin is the most frequently involved drug. It appears to interfere with the platelet release reaction by acetylation of a platelet membrane protein which may be involved in the synthesis of prostaglandins. Other anti-inflammatory drugs, including indomethacin, phenylbutazone, ibuprophen (Motrin) and clonixin, also interfere with the release reaction but have a shorter acting course than aspirin. Some drugs stimulate adenylcyclase (gliclazide) or block phosphodiesterase, (dipyridamole, caffeine) both of which actions lead to an increase in adenosine cyclic 3':5' monophosphate (cAMP) and decrease aggregation by adenosine diphosphate (ADP). These interactions should be known to clinical scientists since patients using these medicaments may manifest abnormal platelet function tests in the laboratory and mild hemorrhagic syndromes in the clinic.

The reduction of radiation damage to the spinal cord by post-irradiation administration of vasoactive drugs

International Nuclear Information System (INIS)

Hornsey, S.; Myers, R.; Jenkinson, T.

1990-01-01

Radiation induced white matter necrosis in the rat spinal cord is preceded by changes in permeability of the blood brain-barrier, reduced blood flow, and infarction so that the necrosis is an ischemic necrosis. Attempts have been made to modify this developing pathology by the administration of drugs post-irradiation but just prior to the changes in vascular permeability. Verapamyl, a calcium channel blocker, had no effect on the development of ataxia. Dipyridamole, a drug which increases blood flow and reduces thrombosis, delayed and reduced the onset of ataxia. A low iron diet and desferrioxamine which reduces reperfusion injury also delayed and reduced ataxia. These results support the thesis that vascular changes are an important pathway in the development of radiation necrosis and that reperfusion injury is an important factor in the development and exacerbation of radiation damage to the spinal cord

Molecular imaging of alkylguanine-DNA alkyltransferase: further evaluation of radioiodinated derivatives of O {sup 6}-benzylguanine

Energy Technology Data Exchange (ETDEWEB)

Shankar, Sriram [Department of Radiology, Duke University Medical Center, Durham, NC 27710 (United States); Zalutsky, Michael R. [Department of Radiology, Duke University Medical Center, Durham, NC 27710 (United States); Friedman, Henry [Department of Surgery, Duke University Medical Center, Durham, NC 27710 (United States); Department of Pediatrics, Duke University Medical Center, Durham, NC 27710 (United States); Vaidyanathan, Ganesan [Department of Radiology, Duke University Medical Center, Durham, NC 27710 (United States)]. E-mail: ganesan.v@duke.edu

2006-04-15

Purpose: An inverse correlation has been established between tumor levels of the DNA repair protein alkylguanine-DNA alkyltransferase (AGT) and a positive outcome after alkylator chemotherapy. Quantitative imaging of AGT could provide important information for patient-specific cancer treatment. Several radiolabeled analogues of O {sup 6}-benzylguanine (BG), a potent AGT inactivator, have been developed and shown to be capable of labeling pure AGT protein. Herein, two of these analogues - O {sup 6}-3-[*I]iodobenzylguanine ([*I]IBG) and O {sup 6}-3-[*I]iodobenzyl-2'-deoxyguanosine ([*I]IBdG) - were further evaluated in two murine xenograft models. (AcO){sub 2}-[{sup 131}I]IBdG, a peracetylated derivative of IBdG, also was investigated as an alternative agent. Methods: Several biodistribution studies of radioiodinated IBG and IBdG were performed in TE-671 human rhabdomyosarcoma and DAOY human medulloblastoma murine xenograft models. Mice were treated with BG or its nucleoside analogue dBG to deplete the tumor AGT content. The effect of unlabeled IBG and that of 7,8-benzoflavone (BF), an inhibitor of the cytochrome P-450 isozyme CYP1A2, on the tumor uptake of the tracers was determined. The uptake of (AcO){sub 2}-[{sup 131}I]IBdG along with that of [{sup 125}I]IBdG in DAOY cells in vitro was determined in the presence and absence of a nucleoside transporter inhibitor, dipyridamole. Results: Pretreatment of mice either with BG or dBG failed to reduce tumor levels of [*I]IBG or [*I]IBdG even though such treatments completely depleted tumor AGT content. Treatment of mice with BF increased tumor uptake of [{sup 125}I]IBG by 56%; however, differentiation of tumors with and without AGT still was not possible. (AcO){sub 2}-[{sup 131}I]IBdG, a peracetylated derivative of IBdG, had a higher uptake in vitro in DAOY tumor cells. However, its uptake, like that of [{sup 125}I]IBdG, was blocked by dipyridamole. Conclusions: Taken together, these results suggest that labeled

[The study of anticoagulants selection in platelet-rich plasma preparation].

Science.gov (United States)

Hua, Lei; Lai, Gui; Zhenjun, Liu; Guie, Ma

2015-07-01

To investigate the effect of the anticoagulants on PRP quality, so as to clarify the appropriate anticoagulant used in PRP production. The microstructure change of platelets collected via heparin, citrate, acid citrate dextrose (ACD) and citrate-theophylline-adenosine-dipyridamole ( CTAD) was observed by TEM following time course. The extent of spontaneous activation of platelets in four groups was detected by measuring sP-selectin in plasma. The TGF-β1 release amount of activated PRP of four groups was measured. CTAD is superior to other anticoagulants in maintaining the integrity of platelet structures for a long time and preventing platelet spontaneous activation. ACD slightly surpassed heparin and citrate in above two aspects. ACD-PRP and CTAD-PRP released significantly more TGF-β1 compared with heparin and citrate. The PRP quality and biological effects were strongly associated with the type of Anticoagulants. ACD and CTAD are optimal anticoagulants in PRP production for they can maintain platelet viability at a high level.

Effects of isradipine and other calcium antagonists on arteriovenous-shunt flow in anesthetized rabbits and cats

International Nuclear Information System (INIS)

Hof, R.P.

1989-01-01

The effects of vasodilators on arteriovenous (AV)-shunt flow was investigated in anesthetized cats and rabbits, using the tracer microsphere method. In cats, the calcium antagonist isradipine reduced AV-shunt flow; verapamil showed a similar tendency and nicardipine was without effect. Dihydralazine strongly increased, but nitroglycerin and dipyridamole decreased AV-shunt flow. In rabbits, the effects of isradipine and verapamil were similar to those seen in cats. Sodium nitroprusside had no effect, whereas prazosin, minoxidil, and the potassium-channel activator cromakalim increased AV-shunt flow. The contrasting effects of drugs sharing the same mechanism of action suggest that target-tissue selectivity is more important than the mechanism of action. An increase of AV-shunt flow is unlikely to be beneficial but could be associated with a number of undesirable side effects. It might negatively affect migraine sufferers and, if AV-shunt dilatation shows no tolerance development, it represents an unnecessary hemodynamic burden for the heart

Single photon emission computed tomography of technetium-99m tetrofosmin myocardial perfusion imaging in patients with systemic lupus erythematosus-A preliminary report

International Nuclear Information System (INIS)

Lin, Jen-Jhy; Hsu, Hsiu-Bao; Sun, Shung-Shung; Kao, Chia-Hung; Ho, Shung-Tai

2003-01-01

The purpose of this study was to evaluate the utility of single-photon emission computed tomography (SPECT) of technetium-99m tetrofosmin (Tc-99m TF) myocardial perfusion imaging to detect myocardial involvement in patients with systemic lupus erythematosus (SLE). Three groups of subjects-group 1: 25 SLE female patients with non-specific cardiac symptoms and signs, group 2: 25 female SLE patients without any cardiac symptoms and signs, and group 3: 25 female healthy controls-were evaluated by comparing rest and dipyridamole-stress Tc-99m TF myocardial perfusion SPECT. Tc-99m TF myocardial perfusion SPECT revealed perfusion defects in 88% and 40% of the cases in groups 1 and 2, respectively. However, no cases in group 3 demonstrated myocardial perfusion defects. Tc-99m TF myocardial perfusion SPECT is a useful noninvasive imaging modality to detect cardiac involvement in SLE patients with or without cardiac symptoms and signs. (author)

Micro-scale prediction method for API-solubility in polymeric matrices and process model for forming amorphous solid dispersion by hot-melt extrusion.

Science.gov (United States)

Bochmann, Esther S; Neumann, Dirk; Gryczke, Andreas; Wagner, Karl G

2016-10-01

A new predictive micro-scale solubility and process model for amorphous solid dispersions (ASDs) by hot-melt extrusion (HME) is presented. It is based on DSC measurements consisting of an annealing step and a subsequent analysis of the glass transition temperature (Tg). The application of a complex mathematical model (BCKV-equation) to describe the dependency of Tg on the active pharmaceutical ingredient (API)/polymer ratio, enables the prediction of API solubility at ambient conditions (25°C). Furthermore, estimation of the minimal processing temperature for forming ASDs during HME trials could be defined and was additionally confirmed by X-ray powder diffraction data. The suitability of the DSC method was confirmed with melt rheological trials (small amplitude oscillatory system). As an example, ball milled physical mixtures of dipyridamole, indomethacin, itraconazole and nifedipine in poly(vinylpyrrolidone-co-vinylacetate) (copovidone) and polyvinyl caprolactam-polyvinyl acetate-polyethylene glycol graft copolymer (Soluplus®) were used. Copyright © 2016 Elsevier B.V. All rights reserved.

A comparison of adenine and some derivatives on pig isolated tracheal muscle.

Science.gov (United States)

Bach-Dieterle, Y.; Holden, W. E.; Junod, A. F.

1983-01-01

We studied the muscle relaxation induced by adenine and several adenine derivatives in strips of tracheal smooth muscle from pigs; in addition their metabolism by the tissue was examined. Adenine relaxed tissue which was contracted by carbachol, histamine, or KCl. Adenine's potency was similar to that of adenosine and ATP (threshold about 4 X 10(-5)M). In tissues with carbachol-induced tone, the adenine effect differed from adenosine and ATP by being slower in onset and in 'washout' time. Furthermore, neither dipyridamole nor theophylline modified the response to adenine. The relationship was examined between pharmacological effects and the metabolism of [3H]-adenosine and [3H]-adenine. Both substrates were taken up by the tissue and converted to nucleotides, but relaxation correlated with nucleotide accumulation only in the case of [3H]-adenine. We conclude that the site and mechanism of adenine-induced relaxation is different from that of adenosine and ATP in porcine tracheal muscle. PMID:6571222

Radio-chromatographic determination of plasmatic adenosine deaminase (A.D.); Determination radiochromatographique de l'adenosine deaminase (A.D.)

Energy Technology Data Exchange (ETDEWEB)

Chivot, J J; Depernet, D; Caen, J [Commissariat a l' Energie Atomique, Bruyeres-le-Chatel (France). Centre d' Etudes

1970-07-01

We were able, by using a radio-chromatographic method, to measure an adenosine deaminase activity in normal human heparinized platelet-poor plasma, which can degrade 0.016 {mu}M adenosine. This activity suppressed by heating 56 C for 30 minutes is inhibited by high concentrations of urea and is proportional to the amount of plasma, source of enzyme, in the systems. (authors) [French] Nous avons pu, en utilisant une methode radiochromatographique, mesurer une activite adenosine deaminasique dans le plasma humain pauvre en plaquettes heparine qui peut degrader 0,016 {mu}M d'adenosine. Cette activite qui est supprimee par chauffage a 56 degres pendant 30 minutes, est reduite par conservation a -20 C pendant une semaine, est inhibee par d'importantes concentrations d'uree et ne l'est pas, ni par le dipyridamol, ni par le pHMB. Cette activite est proportionnelle a la quantite de plasma, source d'enzyme, mise dans les differents systemes reactifs. (auteur)

Study of Nicorandil stress perfusion MRI in diagnosing ischemic heart disease

International Nuclear Information System (INIS)

Tateishi, Toshiki; Iwai, Mitsuhiro; Takeda, Soji; Hayashi, Ryuji

2006-01-01

The excellent spatial resolution of myocardial stress perfusion magnetic resonance imaging is effective for the diagnosis of ischemic heart disease. When dipyridamole or adenosine triphosphate is used as a pharmacological stress in cardiac MRI, non-magnetic instruments are required for infusion of these drugs in a MRI room. We attempted to use nicorandil as a pharmacological stressor. Nicorandil exhibited KATP channel opening and nitrate effects, and could be infused without any special instruments. Based on the coronary artery stenosis assessed by coronary angiography, according to the criteria of the American Heart Association (AHA), the sensitivity, specificity and diagnostic accuracy of nicorandil perfusion MRI for the detection of coronary artery stenosis was 85%, 57% and 74.3%, respectively. No major side effects were observed, except for mild hypotension (mean 10 mmHg) after infusion of the drug. It was concluded that myocardial perfusion MRI examination using nicorandil could be performed non-invasively and safely for the evaluation of coronary vessel disease in patients. (author)

Warfarin-induced toxic epidermal necrolysis in combination therapy of Henoch-Schönlein purpura nephritis: a case report.

Science.gov (United States)

Kasahara, Katsuaki; Gotoh, Yoshimitsu; Kuroyanagi, Yoshiyuki; Nagano, China

2017-07-14

Toxic epidermal necrolysis (TEN) is a rare life-threatening condition almost exclusively attributed to drugs. The main etiologic factors for TEN are sulphonamides, anticonvulsants, and antibiotics; however, there are no published reports of warfarin causing TEN. We present the case of a 3-year-old patient who developed TEN while receiving treatment for Henoch-Schönlein purpura nephritis (HSPN). With multiple-drug therapy comprising prednisolone, mizoribine, dipyridamole, and warfarin, it is difficult to detect which drug is the causative agent. While in most cases, diagnosis of the causative drug is based on clinical history without a lymphocyte transformation test (LTT), we performed the test three times and identified the causative drug as warfarin at the late phase. We continued HSPN treatment without warfarin, and results showed good renal function without life-threatening complications. To our knowledge, this is the first report about TEN caused by warfarin. Repeated LTTs could be useful for identifying TEN-causative drugs even in the late phase.

Management of single-ventricle patients with Berlin Heart EXCOR Ventricular Assist Device: single-center experience.

Science.gov (United States)

Mackling, Tracey; Shah, Tejas; Dimas, Vivian; Guleserian, Kristine; Sharma, Mahesh; Forbess, Joseph; Ardura, Monica; Gross-Toalson, Jami; Lee, Ying; Journeycake, Janna; Barnes, Aliessa

2012-06-01

There are minimal data regarding chronic management of single-ventricle ventricular assist device (VAD) patients. This study aims to describe our center's multidisciplinary team management of single-ventricle patients supported long term with the Berlin Heart EXCOR Pediatric VAD. Patient #1 was a 4-year-old with double-outlet right ventricle with aortic atresia, L-looped ventricles, and heart block who developed heart failure 1 year after Fontan. She initially required extracorporeal membrane oxygenation support and was transitioned to Berlin Heart systemic VAD. She was supported for 363 days (cardiac intensive care unit [CICU] 335 days, floor 28 days). The postoperative course was complicated by intermittent infection including methicillin-resistant Staphylococcus aureus, intermittent hepatic and renal insufficiencies, and transient antithrombin, protein C, and protein S deficiencies resulting in multiple thrombi. She had a total of five pump changes over 10 months. Long-term medical management included anticoagulation with enoxaparin, platelet inhibition with aspirin and dipyridamole, and antibiotic prophylaxis using trimethoprim/sulfamethoxazole. She developed sepsis of unknown etiology and subsequently died from multiorgan failure. Patient #2 was a 4-year-old with hypoplastic left heart syndrome who developed heart failure 2 years after bidirectional Glenn shunt. At systemic VAD implantation, he was intubated with renal insufficiency. Post-VAD implantation, his renal insufficiency resolved, and he was successfully extubated to daytime nasal cannula and biphasic positive airway pressure at night. He was supported for 270 days (CICU 143 days, floor 127 days). The pump was upsized to a 50-mL pump in May 2011 for increased central venous pressures (29 mm Hg). Long-term medical management included anticoagulation with warfarin and single-agent platelet inhibition using dipyridamole due to aspirin resistance. He developed increased work of breathing requiring

Detection of myocardial stunning with gated SPECT and its relationship with location, extension and severity of perfusion defects induced by exercise or pharmacologic stress

International Nuclear Information System (INIS)

Mut, F.; Beretta, M.; Vidal, I.; Rener, A.; Alonso, O.

2002-01-01

Aim: To investigate the relationship between transient ventricular dysfunction detected by gated SPECT with the location, extension and severity of ischemic areas in patients with reversible perfusion defects. Material and Methods: We retrospectively studied 83 patients (61±11 yrs., 61 men, 27 with previous MI) submitted for coronary artery disease (CAD) evaluation with 99mTc-MIBI gated SPECT using a 2-day protocol whose perfusion imaging pattern had been reported positive for myocardial ischemia. Stress test was exercise in 54 cases, dipyridamole in 28 and dobutamine in 1. Previous work from our group demonstrated up to 12% change in LVEF from rest to post-stress in a population with low likelihood of CAD and a normal perfusion pattern. Thus, according to % variation of left ventricular ejection fraction (LVEF) from rest to post-stress we further divided the population into 2 subgroups, (A) with less than 12% change in LVEF (n=56) and (B) with more than 12% negative variation (n=27). For evaluation of perfusion, a simplified 7-segment division of the myocardium was used and a combined ischemic score was obtained by multiplying the number of segments with reversible defects by the 1-4 assigned severity score. Results: There was no significant difference between the two groups regarding age, gender, stress result (clinical or ECG), number of fixed perfusion defects or rest LVEF. Dipyridamole test was more frequent among patients of group B. Post-stress LVEF was 49±14% for group A and 41±15% for group B, p=0.0125. Combined ischemic score was 6.82±6.5 vs. 11.96±12 respectively, p=0.014. In patients of group A, defects corresponding to the right coronary territory were more frequent, while the left descending artery territory was more commonly affected in group B patients, however this was not statistically significant. Left circumflex territory was equally affected in both groups. Conclusion: Transient ventricular dysfunction after a stress test can be

The clinician's guide to diagnostic imaging: Cost-effective pathways. Second edition

International Nuclear Information System (INIS)

Grossman, Z.D.; Chew, F.S.; Ellis, D.A.; Brigham, S.C.

1987-01-01

The authors developed a cost-effective approach to imaging studies, based on initial selection of an exam that best addresses the specific clinical problem and obviates the need for additional diagnostic tests. Tightly reasoned arguments compare available imaging options with respect to diagnostic yield, feasibility, risk, and cost. To aid the clinician in making cost comparisons, each paper of the Second Edition lists the dollar cost of relevant imaging studies. The Second Edition has been thoroughly revised to reflect the important advances in diagnostic imaging of the past three years, highlighting CT's expanding role in thoracic and abdominal problems, magnetic resonance imaging as a spectacular diagnostic tool for the central nervous system, and the clinical application of many newly-developed radiopharmaceuticals. New chapters cover breast cancer screening, acute spinal trauma, search for primary cancer of unknown origin, acute anuria, blunt chest trauma, new onset seizures, and spinal cord compression from metastases. Other papers have been rewritten for greater clarity and to incorporate new techniques, like dipyridamole stress testing. A glossary and an introduction define and explain the capabilities and limitations of current techniques

Evaluation of the functionality of biodegradable polymeric platforms for drug delivery systems

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Gioti, M., E-mail: mgiot@physics.auth.gr; Karagkiozaki, V.; Basgiouraki, A.; Karagiannidis, P.G.; Logothetidis, S.

2013-09-15

We present the development of a drug-loaded triple-layer platform consisting of thin film biodegradable polymers, in a properly designed form for the desired gradual degradation. Poly(DL-lactide-co-glycolide) (PLGA (65:35), PLGA (75:25)) and polycaprolactone (PCL) were grown by spin coating technique, to synthesize the platforms with the order PCL/PLGA (75:25)/PLGA (65:35) that determine their degradation rates. The outer PLGA (65:35) layer was loaded with dipyridamole, an antiplatelet drug. Spectroscopic ellipsometry (SE) in the Vis-far UV range was used to determine the nanostructure, as well as the content of the incorporated drug in the as-grown platforms. In situ and real-time SE measurements were carried out using a liquid cell for the dynamic evaluation of the fibrinogen and albumin protein adsorption processes. Atomic force microscopy studies justified the SE results concerning the nanopores formation in the polymeric platforms, and the dominant adsorption mechanisms of the proteins, which were defined by the drug incorporation in the platforms.

Quantitative myocardial thallium single-photon emission computed tomography in normal women: demonstration of age-related differences

International Nuclear Information System (INIS)

Cohen, M.; Touzery, C.; Cottin, Y.; Benoit, T.; Athis, P. d'; Roy, S.; Louis, P.; Wolf, J.E.; Rigo, P.; Brunotte, F.

1996-01-01

The aim of this study is the development of a database of normal women for quantitative analysis of exercise and reinjection myocardial single-photon emission computed tomography (SPET). We studied 101 subjects (40 males and 61 females) with less than 5% likelihood of coronary artery disease. All patients underwent stress and rest thallium-201 myocardial SPET. Myocardial stress was induced by bicycle exercise test (n=51), dipyridamole infusion (n=27) or a combined test (n=23). Multivariate ANOVA showed that the type of stress did not influence the percentage of thallium uptake for each region. Significant differences between men and women were found for the percentage of uptake in the inferior and the anterior wall. The most original finding of this study is the correlation between age and thallium uptake in the three regions of the anterior wall, showing an increase in measured thallium uptake with age for women. Consequently, two groups of women, those under and those over 55 years old, were separated, with a significantly lower tracer uptake in the anterior wall in the younger age group. (orig./MG)

Myocardial perfusion scintigraphy with technetium 99m-MIBI in the diagnosis of coronary artery disease in women

International Nuclear Information System (INIS)

Peix, C. Amalia; Chacon, Deylis; Llerena, Lorenzo; Torres, Maritza; Garcia, Ernesto Javier; Cabrera, Lazaro Omar

2006-01-01

The results of technetium 99 m - methoxy-isobutyl-isonitrile scintigraphy in a one-day protocol: rest - physical or combined stress bicycle plus endovenoous dipyridamole were compared with those of coronary angiography in 20 women referred for the evaluation of pre cordial pain and of the usefulness of myocardial perfusion scintigraphy. The uptake of the radio drug under stress and at rest varied from 93 + - 9 to 94 + - 7 % in the 204 segments with normal uptake under stress, from 67 He articulates it analyzes the reasons or utility of the employment of the radioactive iodine in the diagnosis and treatment of the thyroid affections + - 9 to 75 + - 17 % in the 89 with moderate reduction, and from 33 + - 9 to 64 + - 28 % in the 27 with severe reduction. The qualitative and quantitative uptake analyses coincided in 18 patients. The perfusion scintigraphy and the angiography agreed in 70 % of the patients. It was concluded that the myocardial perfusion scintigraphy with technetium 99 -MIBI contributes to the diagnosis of the coronary artery disease in women

Nuclear cardiology: Myocardial perfusion and function

International Nuclear Information System (INIS)

Seldin, D.W.

1991-01-01

Myocardial perfusion studies continue to be a major focus of research, with new investigations of the relationship of exercise-redistribution thallium imaging to diagnosis, prognosis, and case management. The redistribution phenomenon, which seemed to be fairly well understood a few years ago, is now recognized to be much more complex than originally thought, and various strategies have been proposed to clarify the meaning of persistent defects. Pharmacologic intervention with dipyridamole and adenosine has become available as an alternative to exercise, and comparisons with exercise imaging and catheterization results have been described. Thallium itself is no longer the sole single-photon perfusion radiopharmaceutical; two new technetium agents are now widely available. In addition to perfusion studies, advances in the study of ventricular function have been made, including reports of studies performed in conjunction with technetium perfusion studies, new insights into cardiac physiology, and the prognostic and case-management information that function studies provide. Finally, work has continued with monoclonal antibodies for the identification of areas of myocyte necrosis. 41 references

Severe glomerulonephritis complicated by coagulopathy: treatment with anticoaguland and immunosuppresive drugs.

Science.gov (United States)

Robson, A M; Cole, B R; Kienstra, R A; Kissane, J M; Alkjaersig, N; Fletcher, A P

1977-06-01

Serial determinations, using plasma fibrinogen gel chromatography as well as standard methodology, demonstrated that six children with severe glomerulonephritis, characterized on renal biopsy by glomerular necrosis and crescent formation, had persistent evidence of intravascular coagulation. Based on these observations, therapy with anticoagulants and azathicoagulants and azathioprine was instituted for one year; treatment with anticoagulants was continued for a second year. Anticoagulant therapy was initiated with heparin, followed by oral anticoagulation with phenindione and dipyridamole. In contrast to our earlier experience with similar patients, each of the present patients improved. Urinalyses returned to normal and glomerular filtration rates to near normal values in all patients at the end of the treatment period and have remained so for up to 3.9 years since treatment has been completed. Post-treatment biopsies showed remarkable improvement, with virtually no glomerulosclerosis even in patients who had had a high incidence of glomerular crescents before treatment. It is suggested that the therapeutic regimen favorably influenced the natural history of disease and that plasma fibrinogen chromatographic findings may be helpful in selecting patients likely to benefit from the use of anticoagulant therapy.

Incremental value of contrast myocardial perfusion to detect intermediate versus severe coronary artery stenosis during stress-echocardiography

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Ugo Fabrizio

2010-05-01

Full Text Available Abstract Background We aimed to compare the incremental value of contrast myocardial perfusion imaging (MPI for the detection of intermediate versus severe coronary artery stenosis during dipyridamole-atropine echocardiography (DASE. Wall motion (WM assessment during stress-echocardiography demonstrates suboptimal sensitivity to detect coronary artery disease (CAD, particularly in patients with isolated intermediate (50%-70% coronary stenosis. Methods We performed DASE with MPI in 150 patients with a suspected chest pain syndrome who were given clinical indication to coronary angiography. Results and discussion When CAD was defined as the presence of a ≥50% stenosis, the addition of MPI increased sensitivity (+30% and decreased specificity (-14%, with a final increase in total diagnostic accuracy (+16%, p Conclusions The addition of MPI on top of WM analysis during DASE increases the diagnostic sensitivity to detect obstructive CAD, whatever its definition (≥50% or > 70% stenosis, but it is mainly driven by the sensitivity increase in the intermediate group (50%-70% stenosis. The total diagnostic accuracy increased only when defining CAD as ≥50% stenosis, since in patients with severe stenosis (> 70% the decrease in specificity is not counterbalanced by the minor sensitivity increase.

Extraction and myocardial distribution of IPBDA potentials of lipophylic cations for use as thallium substitutes

International Nuclear Information System (INIS)

Rigo, P.; Woo, D.V.; Tanaka, T.; Wong, D.F.; Dannals, R.; Wagner, H.N. Jr.; Becker, L.C.

1984-01-01

Potassium analogs have been used for several years as clinical indicators of myocardial blood flow, but the value of thallium is limited by its long half life and low energy photons. We have tested 4-iodiphenylbenzyldimethylammonium (IPBDA) a radio-iodinated cation as a potential thallium substitute in a series of 7 mongrel dogs. First pass myocardial and systemic extraction were determined using the double tracer technique, with technetium albumin as reference. Tissue iodine 125 IPBDA distributions were compared to microspheres under a variety of pathophysiological conditions (control, myocardial infarction, coronary artery stenosis, Dipyridamole infusion). First pass extraction averaged 73% in normal controls (3 determinations), 66.1% in dogs with LAD occlusion (4 determination) and 40.1% in dogs receiving persantine (with or without coronary stenosis or occlusion) (5 determinations). Tissue microspheres and IPBDA distribution correlated in each dog (r=.75, to .85) but the relationship was not linear, IPBDA underestimating myocardial blood flow at high flow. Iodinated IPBDA is a potential thallium substitute due to the better physical characteristics of iodine 123. It shares however the biological limitations of potassium and analogs: a variable extraction and a non linear relation to flow. (Author)

Comparison of exercise and pharmacological stress gated SPECT in detecting transient left ventricular dysfunction

International Nuclear Information System (INIS)

Demir, Hakan; Tan, Yusuf Z.; Isgoren, Serkan; Gorur, Gozde D.; Kozdag, Guliz; Ural, Ertan; Berk, Fatma

2008-01-01

Transient left ventricular contractile dysfunction (TLVD) is observed owing to post-exercise stunning in patients with coronary artery disease (CAD). Pharmacological stimulation differs from exercise stress because it does not cause demand ischemia. The aim of this study was to determine whether TLVD could also be seen after pharmacological stress (dipyridamole). Of the patients in whom gated single-photon emission computed tomography (GSPECT) was performed in our institution from January 2004 to April 2007, 439 subjects with known or suspected CAD were included in the study. GSPECT was performed for all patients following exercise (group I, n=220) or pharmacological stress (group II, n=219) according to a 2-day (stress-rest) protocol after injection of Tc-99m methoxyisobutyl-isonitrile (MIBI). Stress, rest, and difference (stress-rest value) left ventricular ejection fractions (SLVEF, RLVEF, and DLVEF) and transient ischemic dilatation (TID) ratio were derived automatically. Summed stress score, summed rest score, and summed difference score (SDS) for myocardial perfusion were calculated using a 20-segment model and a five-point scoring system. An SDS >3 was considered as ischemic. On the basis of the perfusion findings, patients were subdivided into a normal (group A, n=216) and ischemia group (group B, n=223). DLVEF and perfusion scores of all groups were compared. Relationships between DLVEF and perfusion, and between TID ratio and DLVEF were also evaluated. Stress-induced ischemia was observed in 223 of 439 patients (50.8%). In group A, the difference between stress and rest LVEF values was not significant (P=0.670 and P=0.200 for groups IA and IIA, respectively). However, LVEF was significantly decreased after stress compared with rest values for group B (P<0.0001 for groups IB and IIB). TLVD (≤-5% for DLVEF) was observed in 20 of 216 (9%) and 81 of 223 subjects (36%) in patients in groups A and B, respectively (P<0.0001). In group I, we found TLVD in 46 of

The influence of lactate and dipyridamole on myocardial fatty acid metabolism in man, traced with 123I-17-iodoheptadecanoic acid

International Nuclear Information System (INIS)

Duwel, C.M.B.; Visser, F.C.; Eenige, M.J. van; Roos, J.P.; Westera, G.

1990-01-01

Changes in myocardial metabolism can be detected externally by registration of time-activity curves after administration of radioiodinated fatty acids. In this scintigraphic study the influence of lactate on fatty acid metabolism was investigated in the normal human myocardium, traced with 123 I-17-iodoheptadecanoic acid ( 123 I-17-HDA). In patients (paired, n=7) lactate loading decreased the uptake of 123 I-17-HDA significantly from 27 (control:22-36) to 20 counts/min/pixel (16-31; p 123 I-17-HDA scintigraphy of the heart. (orig.) [de

The relaxant effect induced by Allium sativum L. bulb aqueous extract on rat isolated trachea

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Fehri, Badreddine; Ahmed, Mueen K.K.; Aiache, Jean-Marc

2011-01-01

Background: Garlic plays an important role in complementary and alternative medicine. Most people believe in and use herbal products even when they have not been as thoroughly researched as garlic. Garlic is also known for its beneficial effects on the cardiovascular system. Materials and Methods: The relaxant effect of Allium sativum L. bulb aqueous extract (ASBAE) containing 0.06%-0.10% of allicin was studied on isolated smooth muscle of trachea of rats precontracted using acetylcholine (10−5 M). Results: It was found that ASBAE induced a dose-dependent relaxation with recorded EC 50 values of 71.87 ± 5.90 µg/mL (n = 7). Pretreatments with mepyramine (10−7 M), methysergide (10−7 M), caffeine (10−6 M), theophylline (10−6 M), nifedipine (10−6 M), and dipyridamole (10−6 M) did not alter ASBAE concentration-response curves. In turn, concentration-response curves to ASBAE were significantly shifted toward right in the presence of aspirin (3.10−3 M), indomethacin (10−6 M), prazosin (10−6 M), and propranolol (10−7 M). Conclusion: It is suggested that the recorded relaxation results are due to the release of prostaglandins E 1 and E 2 consecutively to α- and β-adrenoreceptor stimulation. PMID:21472073

Studies on the interaction of lidocaine with plasma proteins

International Nuclear Information System (INIS)

Adotey, J.

1985-01-01

This study sought to quantitate lidocaine's interaction with alpha-1-acid glycoprotein (AAG), human serum albumin (HSA), and AAG in the presence of HSA, and to determine the extent of displacement of lidocaine from its binding site(s) by selected cardiovascular drugs (dipyridamole, disopyramide and quinidine). Since the limited experimental work reported in this area has involved the use of a single lidocaine concentration, this study involved the evaluation of a range of lidocaine concentrations. Lidocaine interaction with plasma proteins (AAG and HSA) was studied at 37 0 C using an isothermal equilibrium dialysis system and 14 C-lidocaine HCl. A dialysis membrane (M.W. cutoff 12,000 to 14,000) separated the two chambers of each dialysis cell. The extent of 14 C-lidocaine dialysis was studied with respect to both drug and protein concentrations. Aliquots of each chamber of each of the cells were subjected to liquid scintillation counting (LSC) analyses for 14 C-lidocaine. The ratio of bound to free (R/F) lidocaine was evaluated as a function of AAG concentration from the LSC data. Scatchard and/or Rosenthal analyses were employed to evaluate n and k values where appropriate. Linear and multiple linear regression analyses of the data were appropriately performed

Interventional vascular radiology

International Nuclear Information System (INIS)

Yune, H.Y.

1984-01-01

The papers published during this past year in the area of interventional vascular radiology presented some useful modifications and further experiences both in the area of thromboembolic therapy and in dilation and thrombolysis, but no new techniques. As an introductory subject, an excellent monograph reviewing the current spectrum of pharmacoangiography was presented in Radiographics. Although the presented material is primarily in diagnostic application of various pharmacologic agents used today to facilitate demonstration of certain diagnostic criteria of various disease processes, both vasodilatory and vasoconstrictive reaction to these agents are widely used in various therapeutic vascular procedures. This monograph should be reviewed by every angiographer whether or not he or she performs interventional procedures, and it would be very convenient to have this table available in the angiography suite. In a related subject, Bookstein and co-workers have written an excellent review concerning pharmacologic manipulations of various blood coagulative parameters during angiography. Understanding the proper method of manipulation of the bloodclotting factors during angiography, and especially during interventional angiography, is extremely important. Particularly, the method of manipulating the coagulation with the use of heparin and protamine and modification of the platelet activity by using aspirin and dipyridamole are succinctly reviewed. The systemic and selective thrombolytic activities of streptokianse are also discussed

Transient coronary vasodilatory impairment after direct PTCA in acute myocardial infarction

International Nuclear Information System (INIS)

Yamabe, Hiroshi; Kim, Susik; Hashimoto, Yasunori; Fujita, Hideki; Yano, Takashi; Iwahashi, Masanori; Maeda, Kazumi; Yokoyama, Mitsuhiro

1995-01-01

To determine whether transient impairment in coronary artery reserve may occur after acute percutaneous transluminal coronary angioplasty (PTCA) and may be related with myocardial stunning in acute myocardial infarction (MI), 14 paients were examined by dipyridamole (dip) thallium-201 scintigraphy. Of these patients, 13 patients had recanalization after PTCA and one had spontaneous recanalization. Eight and 6 patients were classified as the 'fill-in phenomenon' and as no 'fill-in phenomenon', respectively, on reinjection thallium-201 images after delayed imaging. In the group of 'fill-in phenomenon', thallium uptake was significantly increased both on early images in chronic MI and on reinjection images, as compared with that on early images in acute MI. In the group of 'no fill-in phenomenon', on the contrary, thallium uptake was significantly decreased. An increase of thallium-201 uptake from early images in acute MI to reinjection images was positively correlated with changes in thallium-201 uptake on early images from acute to chronic MI. There was a positive correlation between the arteriographic improvement of wall motion abnormality in the infart zones and % thallium-201 uptake. These data indicate that transient functional impairment may occur not only in the myocardium but also in coronary fine vessels in MI patients successfully treated with direct PTCA. (N.K.)

The review of myocardial positron emission computed tomography and positron imaging by gamma camera

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Ohtake, Tohru [Tokyo Univ. (Japan). Faculty of Medicine

1998-04-01

To measure myocardial blood flow, Nitrogen-13 ammonia, Oxygen-15 water, Rubidium-82 and et al. are used. Each has merit and demerit. By measuring myocardial coronary flow reserve, the decrease of flow reserve during dipyridamole in patients with hypercholesterolemia or diabetes mellitus without significant coronary stenosis was observed. The possibility of early detection of atherosclerosis was showed. As to myocardial metabolism, glucose metabolism is measured by Fluorine-18 fluorodeoxyglucose (FDG), and it is considered as useful for the evaluation of myocardial viability. We are using FDG to evaluate insulin resistance during insulin clamp in patients with diabetes mellitus by measuring glucose utilization rate of myocardium and skeletal muscle. FFA metabolism has been measured by {sup 11}C-palmitate, but absolute quantification has not been performed. Recently the method for absolute quantification was reported, and new radiopharmaceutical {sup 18}F-FTHA was reported. Oxygen metabolism has been estimated by {sup 11}C-acetate. Myocardial viability, cardiac efficiency was evaluated by oxygen metabolism. As to receptor or sympathetic nerve end, cardiac insufficiency or cardiac transplantation was evaluated. Imaging of positron emitting radiopharmaceutical by gamma camera has been performed. Collimator method is clinically useful for cardiac imaging of viability study. (author). 54 refs.

Time-course of myocardial perfusion and fatty acid metabolism after coronary reperfusion

International Nuclear Information System (INIS)

Sochor, H.; Pachinger, O.; Ogris, E.; Probst, P.; Kaindl, F.

1985-01-01

To investigate the relationship and time-course of myocardial perfusion and behaviour of fatty acid uptake and clearance following reperfusion, the authors studied 19 patients after successful intracoronary thrombolysis with Tl-201 and I-123 hepta-decanoic acid (HDA) and planar imaging. Pts were studied acute (A: 48 hours), early (E:6-8 days) and late (L:6-12 months). %-defect size and relative tracer uptake were determined for both markers as well as t1/2 of the early clearance phase for HDA. Late Tl was done as stress test study after dipyridamole infusion. As in a previous report acute HDA uptake-defects were larger than Tl (38 +- 10% vs 24 +- 9%, p<0.05) suggesting a larger area of metabolic impairment than outlined by perfusion. HDA and Tl uptake at A correlated significantly (p<0.01, r=0.86) but HDA uptake was 19% lower than Tl and not different at E and L. Tl stress studies exhibited in 74% reversible ischemia in the area of ''metabolic recovery''. The authors conclude that early after reperfusion uptake of HDA is frequently impaired despite improved perfusion suggesting metabolic derangement showing a slow recovery over time. A multiple tracer approach including metabolic markers may improve the characterization of reperfused myocardium

Coronary flow reserve/diastolic function relationship in angina-suffering patients with normal coronary angiography.

Science.gov (United States)

Anchisi, Chiara; Marti, Giuliano; Bellacosa, Ilaria; Mary, David; Vacca, Giovanni; Marino, Paolo; Grossini, Elena

2017-05-01

Coronary blood flow and diastolic function are well known to interfere with each other through mechanical and metabolic mechanisms. We aimed to assess the relationship between coronary flow reserve (CFR) and diastolic dysfunction in patients suffering from angina but with normal coronary angiography. In 16 patients with chest pain and angiographically normal coronary arteries, CFR was measured using transthoracic echo-Doppler by inducing hyperemia through dipyridamole infusion. Diastolic function (E/A, deceleration time, isovolumetric relaxation time [IVRT], propagation velocity [Vp]) and left ventricular mass were evaluated by means of two-dimensional transthoracic echocardiography. The patients were initially divided into two groups on the grounds of CFR only (ACFR: altered CFR, n = 9; NACFR: unaltered CFR, n = 7). Thereafter they were divided into four groups on the grounds of CFR and diastolic function (NN: normal; AA: altered CFR/diastole; AN: altered CFR/normal diastole; NA: normal CFR/altered diastole). Most of the subjects were scheduled in AA (n = 8) or NA (n = 5) groups, which were taken into consideration for further analysis. Patients were not different regarding various risk factors. ACFR and AA patients were older with normal body weight in comparison with NACFR and NA patients (P relationship between altered CFR and diastole.

Elevation of extracellular adenosine enhances haemopoiesis-stimulating effects of G-CSF in normal and gamma-irradiated mice

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Hofer, M.; Pospisil, M.; Netikiva, J.; Hola, J. [Institute of Biophysics, Academy of Sciences of the Czech Republic (Czech Republic)

1997-03-01

Effects of combined treatment with drugs elevating extracellular adenosine (dipyridamole /DP/, inhibiting the extracellular uptake of adenosine, and adenosine monophosphate /AMP/, an adenosine pro-drug), and G-CSF (granulocyte colony-stimulating factor) on haemopoiesis of normal and gamma-irradiated mice were ascertained. The agents were administered alone or in combination in a 4-day regimen. In normal, unirradiated animals, the haematological endpoints were determined 24 hours after the completion of the treatment. It was shown that the effects of G-CSF, i.e., increases in peripheral blood neutrophils, granulocyte-macrophage progenitor cells (GM-CFC) and morphologically recognizable granulocyte cells in femoral marrow and a decrease in the marrow erythroid cells, can be enhanced by the combination of DP plus AMP administrated 30 minutes before G-CSF. Furthermore, it was found that the stimulatory action of DP plus AMP was expressed particularly at lower doses of G-CSF (1.5, 3, and 4.5 {mu}g/d). In experiments with irradiated mice, when the 4-day therapeutic regimen was applied on days 3 to 6 following irradiation with the dose of 4 Gy, analogical stimulation of granulopoiesis was observed in the recovery phase on days 14 and 18 after irradiation. As example, see Fig. 1 for counts of granulocyte cells in femoral bone marrow. (authors)

Elevation of extracellular adenosine enhances haemopoiesis-stimulating effects of G-CSF in normal and gamma-irradiated mice

International Nuclear Information System (INIS)

Hofer, M.; Pospisil, M.; Netikiva, J.; Hola, J.

1997-01-01

Effects of combined treatment with drugs elevating extracellular adenosine (dipyridamole /DP/, inhibiting the extracellular uptake of adenosine, and adenosine monophosphate /AMP/, an adenosine pro-drug), and G-CSF (granulocyte colony-stimulating factor) on haemopoiesis of normal and gamma-irradiated mice were ascertained. The agents were administered alone or in combination in a 4-day regimen. In normal, unirradiated animals, the haematological endpoints were determined 24 hours after the completion of the treatment. It was shown that the effects of G-CSF, i.e., increases in peripheral blood neutrophils, granulocyte-macrophage progenitor cells (GM-CFC) and morphologically recognizable granulocyte cells in femoral marrow and a decrease in the marrow erythroid cells, can be enhanced by the combination of DP plus AMP administrated 30 minutes before G-CSF. Furthermore, it was found that the stimulatory action of DP plus AMP was expressed particularly at lower doses of G-CSF (1.5, 3, and 4.5 μg/d). In experiments with irradiated mice, when the 4-day therapeutic regimen was applied on days 3 to 6 following irradiation with the dose of 4 Gy, analogical stimulation of granulopoiesis was observed in the recovery phase on days 14 and 18 after irradiation. As example, see Fig. 1 for counts of granulocyte cells in femoral bone marrow. (authors)

Prognostic value of technetium-99m-labeled single-photon emission computerized tomography in the follow-up of patients after their first myocardial revascularization surgery

Directory of Open Access Journals (Sweden)

Márcia Maria Sales dos Santos

2003-01-01

Full Text Available OBJECTIVE: To assess the prognostic value of Technetium-99m-labeled single-photon emission computerized tomography (SPECT in the follow-up of patients who had undergone their first myocardial revascularization. METHODS: We carried out a retrospective study of 280 revascularized patients undergoing myocardial scintigraphy under stress (exercise or pharmacological stress with dipyridamole and at rest according to a 2-day protocol. A set of clinical, stress electrocardiographic and scintigraphic variables was assessed. Cardiac events were classified as "major" (death, infarction, unstable angina and "any" (major event or coronary angioplasty or new myocardial revascularization surgery. RESULTS: Thirty-six major events occurred as follows: 3 deaths, 11 infarctions, and 22 unstable anginas. In regard to any event, 22 angioplasties and 7 new surgeries occurred in addition to major events, resulting a total of 65 events. The sensitivity of scintigraphy in prognosticating a major event or any event was, respectively, 55% and 58%, showing a negative predictive value of 90% and 83%, respectively. Diabetes mellitus, inconclusive stress electrocardiography, and a scintigraphic visualization of left ventricular enlargement were significant variables for the occurrence of a major event. On multivariate analysis, abnormal myocardial scintigraphy was a predictor of any event. CONCLUSION: Myocardial perfusion tomography with Technetium-99m may be used to identify high-risk patients after their first myocardial revascularization surgery.

Cardiac risk assessment before carotid endarterectomy

International Nuclear Information System (INIS)

Rabee, Hussein M.M.

2000-01-01

Preoperative cardiac assessment is an essential step to identify the patients at risk, optimize any dysfunction, anticipate perioperative and postoperative problems and plan special management. Carotid endarterectomy (CEA) has become one of the most commonly performed vascular procedures in Western countries. The awareness of the potential beneficial role and hazards of CEA is not proportionate to the magnitude of this problem in our countries, not only among patients, but also among the medical disciplines. This report is a retrospective analysis of the prevalence of coronary artery diseases among 442 patients who were referred to the Division of Vascular Surgery at the King Khalid University Hospital in Riyadh, Saudi Arabia with suspicion of carotid artery disease. Eighty-two patients proved to have significant carotid artery stenosis and had thorough preoperative cardiac assessment by senior cardiologist. All cases had clinical assessment and ECG, 66 cases had echocardiogram examination, 44 had Dipyridamole Thallium-scan and 12 had coronary angiogram. Sixty-eight patients underwent 76 carotid endarterectomy. Four of them had MI and only one case died during preoperative period. This study shows that cardiac screening studies have a potential role in the candidates for carotid surgery in influencing the decision to operate and intensify of perioperative monitoring and care. We believe that the teamwork should involve vascular surgeons, cardiologist and anesthetist to manage such critical patients properly. (author)

Serial assessment of left ventricular function in various patient groups with Tl-201 gated myocardial perfusion SPECT

International Nuclear Information System (INIS)

Wei Lingge; Kadoya, Masumi; Momose, Mitsuhiro; Kurozumi, Masahiro; Matsushita, Tsuyoshi; Yamada, Akira

2007-01-01

The present study was performed to assess stress-related left ventricular (LV) function variations in various patient groups and to determine if they were affected by sex or the type of stress experienced. We used thallium (Tl)-201 gated myocardial perfusion single-photon emission computed tomography (SPECT) for the analysis. A total of 270 patients were examined by electrocardiography-gated myocardial perfusion SPECT imaging to assess LV function. After injection of Tl-201 at a dose of 111 MBq at peak stress, SPECT scans were acquired at 10 min (after stress) and 3 h (rest) after injection on a three-headed camera. In the normal perfusion group, the mean LV ejection fraction (LVEF) was significantly higher, and both the end-diastolic volume index (EDVI) and end-systolic volume index (ESVI) were significantly lower in women than in men (P<0.05). Poststress stunning occurred in 29 of 98 patients (30.0%) in the ischemia group and in 42 of 90 patients (46.7%) in the fixed group. There was a significant difference in poststress stunning between bicycle ergometer stress and dipyridamole stress (P<0.05). In patients with normal perfusion, LVEF, EDVI, and ESVI determined by gated Tl-201 SPECT should be corrected for sex. In addition, the influence of the type of stress should be considered when assessing stress-related LV function variations. (author)

Angiogenesis PET Tracer Uptake (68Ga-NODAGA-E[(cRGDyK]2 in Induced Myocardial Infarction in Minipigs

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Thomas Rasmussen

2016-06-01

Full Text Available Angiogenesis is part of the healing process following an ischemic injury and is vital for the post-ischemic repair of the myocardium. Therefore, it is of particular interest to be able to noninvasively monitor angiogenesis. This might, not only permit risk stratification of patients following myocardial infarction, but could also facilitate development and improvement of new therapies directed towards stimulation of the angiogenic response. During angiogenesis endothelial cells must adhere to one another to form new microvessels. αvβ3 integrin has been found to be highly expressed in activated endothelial cells and has been identified as a critical modulator of angiogenesis. 68Ga-NODAGA-E[c(RGDyK]2 (RGD has recently been developed by us as an angiogenesis positron-emission-tomography (PET ligand targeted towards αvβ3 integrin. In the present study, we induced myocardial infarction in Göttingen minipigs. Successful infarction was documented by 82Rubidium-dipyridamole stress PET and computed tomography. RGD uptake was demonstrated in the infarcted myocardium one week and one month after induction of infarction by RGD-PET. In conclusion, we demonstrated angiogenesis by noninvasive imaging using RGD-PET in minipigs hearts, which resemble human hearts. The perspectives are very intriguing and might permit the evaluation of new treatment strategies targeted towards increasing the angiogenetic response, e.g., stem-cell treatment.

Homology modeling, docking studies and molecular dynamic simulations using graphical processing unit architecture to probe the type-11 phosphodiesterase catalytic site: a computational approach for the rational design of selective inhibitors.

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Cichero, Elena; D'Ursi, Pasqualina; Moscatelli, Marco; Bruno, Olga; Orro, Alessandro; Rotolo, Chiara; Milanesi, Luciano; Fossa, Paola

2013-12-01

Phosphodiesterase 11 (PDE11) is the latest isoform of the PDEs family to be identified, acting on both cyclic adenosine monophosphate and cyclic guanosine monophosphate. The initial reports of PDE11 found evidence for PDE11 expression in skeletal muscle, prostate, testis, and salivary glands; however, the tissue distribution of PDE11 still remains a topic of active study and some controversy. Given the sequence similarity between PDE11 and PDE5, several PDE5 inhibitors have been shown to cross-react with PDE11. Accordingly, many non-selective inhibitors, such as IBMX, zaprinast, sildenafil, and dipyridamole, have been documented to inhibit PDE11. Only recently, a series of dihydrothieno[3,2-d]pyrimidin-4(3H)-one derivatives proved to be selective toward the PDE11 isoform. In the absence of experimental data about PDE11 X-ray structures, we found interesting to gain a better understanding of the enzyme-inhibitor interactions using in silico simulations. In this work, we describe a computational approach based on homology modeling, docking, and molecular dynamics simulation to derive a predictive 3D model of PDE11. Using a Graphical Processing Unit architecture, it is possible to perform long simulations, find stable interactions involved in the complex, and finally to suggest guideline for the identification and synthesis of potent and selective inhibitors. © 2013 John Wiley & Sons A/S.

Clinical characteristics in patients showing ischemic electrocardiographic changes during adenosine triphosphate loading single-photon emission computed tomography

International Nuclear Information System (INIS)

Ohtaki, Yuka; Chikamori, Taishiro; Hida, Satoshi; Tanaka, Hirokazu; Igarashi, Yuko; Hatano, Tsuguhisa; Usui, Yasuhiro; Miyagi, Manabu; Yamashina, Akira

2010-01-01

Although ischemic electrocardiographic (ECG) changes during dipyridamole or adenosine infusion have been reported as a marker for severe coronary artery disease (CAD), few studies have focused on ST-segment changes with adenosine triphosphate (ATP)-loading myocardial single-photon emission computed tomography (SPECT). Between January 2003 and August 2008, 4650 consecutive patients underwent ATP-loading SPECT. After 1412 patients with left bundle branch block, pacemaker rhythm, or previous coronary revascularization were excluded, 16 out of 3238 patients (0.5%) showed ischemic ST-segment depression during ATP-loading myocardial SPECT. They were aged 67±11 years; 10 were men and 6 women. Of these patients, 8 demonstrated perfusion abnormalities, whereas the remaining 8 showed normal myocardial perfusion imaging. In 6 of the 8 patients with abnormal SPECT, coronary angiography was performed, revealing left main trunk disease in 1 patient, 3-vessel disease in 4, 1-vessel disease with proximal left ascending artery occlusion in 1, and an insignificant lesion in 1. By contrast, no major cardiac event was observed in the 8 patients with normal SPECT during follow-up for an average of 2 years. The prevalence of ischemic ST-segment changes during ATP loading is very rare. However, this finding should be taken into account since almost half of the patients, particularly those with perfusion abnormalities, may have severe CAD which requires coronary revascularization. (author)

Myocardial perfusion scintigraphy 2006 in Germany. Results of the query and current status

International Nuclear Information System (INIS)

Lindner, O.; Burchert, W.; Bengel, F.M.; Zimmermann, R.; Dahl, J. vom; Schaefer, W.; Schober, O.; Kluge, R.; Schaefers, M.

2008-01-01

Aim: this second survey was to deliver further information on myocardial perfusion scintigraphy (MPS) in Germany in 2006. Method: 351 questionnaires were evaluated: 207 private practices (PP), 117 hospitals (HO), 27 from university hospitals (UH). Results: MPS of 106 331 patients were reported, 85% were investigated with 99m Tc-perfusion tracers. 74% [2005 = 72%] were performed in PP, 17% [2005 = 15%] in HO and 9% [2005 = 13%] in UH. PP, which participated in 2005 and 2006, demonstrated an increase by 3,9% (HO 0%, UH -13,0%). The type of stress was pharmacological in 27% [2005 = 22%]; 54% adenosine (of these 29% with exercise), 37% dipyridamole (of these 56% with exercise), and 9% dobutamine. Gated SPECT was performed in 42% [2005 = 36%] of all rest- and in 39% [2005 32%] of all stress MPS. An attenuation correction was used by 69 [2005 = 78] institutions. 40% of all MPS were performed in patients suspected to have CAD. 24% of all institutions reported changes in the use of MPS by competing methods. Conclusion: there is a small increase of MPS between 2005 and 2006 despite competing methods. Gated SPECT has experienced more acceptance. Suspicion of CAD is an important indication of MPS. In order to tap the full potential of MPS a gated SPECT should be performed routinely. (orig.)

The comparison of nitroglycerin interventional dual-isotope myocardium perfusion imaging and 201Tl re-injection imaging to detect viable myocardium

International Nuclear Information System (INIS)

Gao Zhou; Shi yu; Chen Hongyan; Jia Shaowei

2002-01-01

Objective: Employing the differences in physical properties of 99m Tc-MIBI and 201 Tl, the authors discuss the contrast result of nitroglycerin interventional dual-isotope myocardium perfusion imaging and 201 Tl re-injection imaging to detect viable myocardium so that authors can enhance the image quality and shorten the examination time. Method: 34 OMI patients took the 99m Tc-MIBI and 201 Tl dual-isotope myocardium perfusion imaging and 201 Tl re-injection imaging respectively in two weeks. During the peak of normal dipyridamole stress i.v. 201 Tl 100 MBq was given and myocardium imaging was taken 15 min later. The dual-isotope group was given nitroglycerin 1mg under the tongue. Five min later, i.v. 99m Tc-MIBI 1110 mBq was given. In 201 Tl re-injection group i.v. 201 Tl 40 MBq was given 4 hour later and were imaged. Among the 34 OMI patients, 19 patients undertook another 99m Tc-MIBI static imaging. Results: There are no obvious differences between nitroglycerin interventional dual-isotope myocardium perfusion imaging and 201 Tl re-injection imaging in detection rate of viable myocardium, χ 2 =0.823, p>0.25. But they have great difference in perfusion changed sectional myocardium absorb rate, t=2.73, p 2 =27.867, p 201 Tl re-injection imaging

Iliac artery mural thrombus formation. Effect of antiplatelet therapy on 111In-platelet deposition in baboons

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Hanson, S.R.; Paxton, L.D.; Harker, L.A.

1986-01-01

To measure the rate, extent, and time course of arterial mural thrombus formation in vivo and to assess the effects of antiplatelet therapy in that setting, we have studied autologous 111 In-platelet deposition induced by experimental iliac artery aneurysms in baboons. Scintillation camera imaging analyses were performed at 1, 24, 48, and 72 hours after implantation of the device. Correction for tissue attenuation was determined by using a small, comparably located 111 In source implanted at the time of surgery. In five animals, 111 In-platelet activity accumulated progressively after device implantation, reaching a maximum after the third day. Repeat image analysis carried out 2 weeks after the surgical procedure also showed progressive accumulation of 111 In-platelets over 3 days but at markedly reduced amounts as compared with the initial study. In five additional animals, treatment with a combination of aspirin and dipyridamole begun 1 hour after surgical implantation reduced 111 In-platelet deposition to negligible levels by the third day. Although platelet survival time was shortened and platelet turnover was reciprocally increased in all operated animals, platelet survival and turnover were not affected by antiplatelet therapy. We conclude that, in contrast to platelet survival and turnover measurements, 111 In-platelet imaging is a reliable and sensitive method for localizing and quantifying focal arterial thrombi and for assessing the effects of antiplatelet therapy

PHARMACOTHERAPY ANALYSIS OF ACUTE ST-ELEVATION MYOCARDIAL INFARCTION IN HOSPITALS OF VARIOUS TYPES

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R. M. Magdeev

2011-01-01

Full Text Available Aim. To evaluate pharmacotherapy of ST-elevation myocardial infarction (STEMI in cardiology departments of Saratov hospitals of various types. Material and methods. The retrospective pharmacoepidemiological study was carried out with involved of 424 hospital charts of STEMI patients, discharged during the year from the cardiology department of Saratov municipal hospital (MH; n=216 and emergency cardiology department of Saratov clinical hospital (CH; n=208. Results. The real practice in the audited hospitals are not fully consistent with current guidelines for the STEMI patients management. The relationship between guidelines compliance and hospital type is clearly seen. Doctors in MH in comparison with them in CH more often prescribed respiratory analeptics (13.4% vs 5.3% , respectively, metabolic drugs (63.4% vs 37.5%, respectively and rarer used beta-blockers (50% vs 88.9%, respectively and thrombolytic therapy (3.7% vs 51%, respectively. In MH dipyridamole was used in 9.6% of patients as an alternative to the acetylsalicylic acid, and clopidogrel was not prescribed. At the same hospital clotting time was determined for monitoring of heparin therapy. Statins were rare used in both hospitals (26% in MH vs 40% in CH. Conclusion. The real clinical practice of STEMI patients management in Saratov hospitals are not completely consistent with current clinical guidelines. There are differences in STEMI patients therapy depending on hospital type.

Design of tablets for the delayed and complete release of poorly water-soluble weak base drugs using SBE7M-β-CD as a solubilizing agent.

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Rao, Venkatramana M; Zannou, Erika A; Stella, Valentino J

2011-04-01

The challenge of designing a delayed-release oral dosage form is significantly increased when the drug substance is poorly water soluble. This manuscript describes the design and characterization of a novel controlled-release film-coated tablet for the pH-triggered delayed and complete release of poorly water-soluble weak base drugs. Delivery of weak bases is specifically highlighted with the use of dipyridamole and prazosin as model compounds. Tailored delayed release is achieved with a combination of an insoluble but semipermeable polymer and an enteric polymer, such as cellulose acetate and hydroxypropyl cellulose phthalate, respectively, as coatings. The extent of the time lag prior to complete release depends on the film-coating composition and thickness. Complete release is achieved by the addition of a cyclodextrin, namely SBE7M-β-CD with or without a pH modifier added to the tablet core to ensure complete solubilization and release of the drug substance. The film-coating properties allow the complex formation/solubilization to occur in situ. Additionally, the drug release rate can be modulated on the basis of the cyclodextrin to drug molar ratio. This approach offers a platform technology for delayed release of potent but poorly soluble drugs and the release can be modulated by adjusting the film-coating composition and thickness and/or the cyclodextrin and pH modifier, if necessary. Copyright © 2010 Wiley-Liss, Inc.

Reproducibility of an automatic quantitation of regional myocardial wall motion and systolic thickening on gated Tc-99m-MIBI myocardial SPECT

International Nuclear Information System (INIS)

Paeng, Jin Chul; Lee, Dong Soo; Cheon, Gi Jeong; Kim, Yu Kyeong; Chung, June Key; Lee, Myung Chul

2000-01-01

The aim of this study is to investigate the reproducibility of the quantitative assessment of segmental wall motion and systolic thickening provided by an automatic quantitation algorithm. Tc-99m-MIBI gated myocardial SPECT with dipyridamole stress was performed in 31 patients with known or suspected coronary artery disease (4 with single, 6 with two, 11 with triple vessel disease; ejection fraction 51±14%) twice consecutively in the same position. Myocardium was divided into 20 segments. Segmental wall motion and systolic thickening were calculated and expressed in mm and % increase respectively, using AutoQUANT TM software. The reproducibility of this quantitative measurement of wall motion and thickening was tested. Correlations between repeated measurements on consecutive gated SPECT were excellent for wall motion (r=0.95) and systolic thickening (r=0.88). On Bland-Altman analysis, two standard deviation was 2 mm for repeated measurement of segmental wall motion, and 20% for that of systolic thickening. The weighted kappa values of repeated measurements were 0.807 for wall motion and 0.708 for systolic thickening. Sex, perfusion, or segmental location had no influence on reproducibility. Segmental wall motion and systolic thickening quantified using AutoQUANT TM software on gated myocardial SPECT offers good reproducibility and is significantly different when the change is more than 2 mm for wall motion and more than 20% for systolic thickening

Radionuclide methods of identifying patients who may require coronary artery bypass surgery

International Nuclear Information System (INIS)

Beller, G.A.; Gibson, R.S.; Watson, D.D.

1985-01-01

Myocardial thallium-201 ( 201 Tl) scintigraphy or radionuclide angiography performed in conjunction with exercise stress testing can provide clinically useful information regarding the functional significance of underlying coronary artery stenoses in patients with known or suspected coronary artery disease. Knowledge of type, location, and extent of myocardial 201 Tl perfusion abnormalities or the severity of exercise-induced global and regional dysfunction has prognostic value. Risk stratification can be undertaken with either radionuclide technique by consideration of the magnitude of the ischemic response and may assist in the selection of patients for coronary artery bypass graft surgery (CABG). In patients with coronary artery disease, delayed 201 Tl redistribution observed on exercise or dipyridamole 201 Tl scintigraphy, particularly when present in multiple vascular regions and associated with increased lung 201 Tl uptake, has been shown to be predictive of an adverse outcome, whereas patients with chest pain and a normal exercise 201 Tl scintigram have a good prognosis with medical treatment. Similarly, a marked fall in the radionuclide ejection fraction from rest to exercise has been found to correlate with high-risk anatomic disease. Another important application of radionuclide imaging in patients being considered for CABG (particularly those with a depressed resting left ventricular ejection fraction) is the determination of myocardial viability and potential for improved blood flow and enhanced regional function after revascularization. 69 references

Significance of Tl-201 redistribution on infarcted region assessed by coronary sinus flow and lactate metabolism

International Nuclear Information System (INIS)

Mori, Takao; Yamabe, Hiroshi; Suda, Kenichirou; Ohnishi, Masataka; Shiotani, Hideyuki; Kurimoto, Yasuyuki; Kobayashi, Katsuya; Maeda, Kazumi; Fukuzaki, Hisashi

1987-01-01

To clarify the significance of Tl-201 redistribution on infarcted regions, coronary sinus and great cardiac vein flow response and lactate metabolism assessed by Webster catheter on 14 infarcted regions after dipyridamole administration were compared with Tl-201 redistribution phenomenon. The regional coronary flow response and lactate extraction ratio in 11 regions with Tl-201 redistribution were lower than those in 3 regions without Tl-201 redistribution. Only 5 regions in 11 with Tl-201 redistribution showed lactate production. The coronary flow response in 5 regions with lactate production was not different from those in 6 without lactate production (1.16 ± 0.89 vs. 1.47 ± 0.67; n.s.). The degree of Tl-201 redistribution assessed by relative activity was not different between regions with and without lactate production. The left ventricular end-diastolic pressure elevated in 5 regions with lactate production (17.8 ± 5.4 mmHg to 29.6 ± 4.9 mmHg; p < 0.05), but didn't in 6 regions without lactate production. Five regions with lactate production contained 4 hypokinetic regions, on the other hand 6 regions without lactate production contained only 3 hypokinetic regions. In conclusion, Tl-201 redistribution on infarcted region revealed not only ischemia but also decreased coronary flow response without lactate production and/or left ventricular dysfunction. (author)

PLLA-PHB fiber membranes obtained by solvent-free electrospinning for short-time drug delivery.

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Cao, K; Liu, Y; Olkhov, A A; Siracusa, V; Iordanskii, A L

2018-02-01

Fibers of poly(L-lactic acid) (PLLA)/polyhydroxybutyrate (PHB) with different concentrations of the drug dipyridamole (DPD) were prepared using solvent-free melt electrospinning to obtain a polymeric drug delivery system. The electrospun fibers were morphologically, structurally, thermally, and dynamically characterized. Crazes that resemble lotus root crevices were interestingly observed in the 7:3 PLLA/PHB fibers with 1% DPD. The crystallinity of PLLA slightly decreased as PHB was incorporated, and the addition of DPD significantly reduced the melting temperature of the composite. The interactions between PLLA and PHB mainly occurred at a proportion of 7:3, and drug encapsulation in the fibers was verified. The kinetic profiles of drug release demonstrated the predominant multiple patterns involving a diffusional stage in the short-term mode of release and kinetic process related to the hydrolysis of the biopolymers. Furthermore, the dynamic behavior of the polymer molecules was evaluated based on the segmental mobility using probe electron spin resonance spectroscopy. The segmental mobility in the amorphous fraction of PLLA decreased with increasing PLLA content. The 9:1 PLLA/PHB system was more resistant to polymer hydrolysis than to the 7:3 system and the rate of diffusion transport was approximately two times higher for the 7:3 PLLA/PHB fibers than for the 9:1 PLLA/PHB fibers.

Improvement of Hyperemic Myocardial Oxygen Extraction Fraction Estimation By A Diffusion Prepared Sequence

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McCommis, Kyle S.; Koktzoglou, Ioannis; Zhang, Haosen; Goldstein, Thomas A.; Northrup, Benjamin E.; Li, Debiao; Gropler, Robert J.; Zheng, Jie

2010-01-01

Myocardial oxygen extraction fraction (OEF) during hyperemia can be estimated using a double-inversion-recovery (DIR) prepared T2-weighted black-blood sequence. Severe irregular ECG-triggering due to elevated heart rate and/or arrhythmias may render it difficult to adequately suppress the flowing left ventricle blood signal and thus potentially cause errors in the estimates of myocardial OEF. Thus, the goal of this study was to evaluate another black-blood technique, a diffusion-weighted (DW)-prepared TSE sequence for its ability to determine regional myocardial OEF during hyperemia. Control dogs and dogs with acute coronary artery stenosis were imaged with both the DIR- and DW-prepared TSE sequences at rest and during either dipyridamole or dobutamine hyperemia. Validation of MRI OEF estimates was performed using blood sampling from the artery and coronary sinus in control dogs. The two methods showed comparable correlations with blood sampling results (R2 = 0.9). Similar OEF estimations for all dogs were observed except for the group of dogs with severe coronary stenosis during dobutamine stress. In these dogs, the DW method provided more physiologically reasonable OEF (hyperemic OEF = 0.75 ± 0.08 vs resting OEF of 0.6) than the DIR method (hyperemic OEF = 0.56 ± 0.10). DW-preparation may be a valuable alternative for more accurate oxygenation measurements during irregular ECG-triggering. PMID:20512871

Treatment of catastrophic antiphospholipid syndrome with defibrotide, a proposed vascular endothelial cell modulator.

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Burcoglu-O'Ral, Arsinur; Erkan, Doruk; Asherson, Ronald

2002-09-01

To define at the molecular level the vascular endothelial cell (VEC) injury characteristics of catastrophic antiphospholipid syndrome (CAPS) and to report successful therapeutic use of a VEC modulator, defibrotide. We describe a 55-year-old man with primary APS with an intractable prothrombotic state (CAPS) resistant to combined therapy with heparin, warfarin, aspirin, and dipyridamole. Treatment with defibrotide was conducted in the context of an investigational phase II protocol where the dose was regulated and individualized by disease/patient-specific molecular and clinical markers. The patient entered complete remission with defibrotide treatment. During treatment, dose dependent pharmacological actions of defibrotide and key stress markers for VEC injury were identified. Evidence of defibrotide's polypharmacology included downregulation of cytokines, notably tumor necrosis factor-alpha, as the earliest effect, cellular differentiation of VEC, possibly with direct regulatory effect over cellular genes, and the reversal of platelet consumption and prothrombotic state. Von Willebrand antigen levels were used as the sole marker to guide therapy. This case demonstrates effective remission of CAPS with defibrotide treatment. In contrast to theories that CAPS is triggered by ischemic and thrombotic tissue damage, these data present VEC injury as the primary and representative lesion of CAPS. The pathogenesis may involve concurrent impairment of different VEC functions. Achieving remission may require a polypharmacologic approach, represented here by use of defibrotide.

Blood flow, flow reserve, and glucose utilization in viable and nonviable myocardium in patients with ischemic cardiomyopathy.

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Zhang, Xiaoli; Schindler, Thomas H; Prior, John O; Sayre, James; Dahlbom, Magnus; Huang, Sung-Cheng; Schelbert, Heinrich R

2013-04-01

The aim of the study was to determine whether glucose uptake in viable myocardium of ischemic cardiomyopathy patients depends on rest myocardial blood flow (MBF) and the residual myocardial flow reserve (MFR). Thirty-six patients with ischemic cardiomyopathy (left ventricular ejection fraction 25 ± 10 %) were studied with (13)N-ammonia and (18)F-fluorodeoxyglucose (FDG) positron emission tomography (PET). Twenty age-matched normals served as controls. Regional MBF was determined at rest and during dipyridamole hyperemia and regional FDG extraction was estimated from regional FDG to (13)N-ammonia activity ratios. Rest MBF was reduced in viable (0.42 ± 0.18 ml/min per g) and nonviable regions (0.32 ± 0.09 ml/min per g) relative to remote regions (0.68 ± 0.23 ml/min per g, p MFRs did not differ significantly (p > 0.05). Compared to MFR in remote myocardium, MFRs in viable regions were similar (1.39 ± 0.56 vs 1.70 ± 0.45, p > 0.05) but were significantly lower in nonviable regions (1.23 ± 0.43, p MFRs (r =-0.424, p MFRs in viable myocardium are associated with increasing glucose extraction that likely reflects a metabolic adaptation of remodeling hibernating myocytes.

Preparation and investigation of novel gastro-floating tablets with 3D extrusion-based printing.

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Li, Qijun; Guan, Xiaoying; Cui, Mengsuo; Zhu, Zhihong; Chen, Kai; Wen, Haoyang; Jia, Danyang; Hou, Jian; Xu, Wenting; Yang, Xinggang; Pan, Weisan

2018-01-15

Three dimensional (3D) extrusion-based printing is a paste-based rapid prototyping process, which is capable of building complex 3D structures. The aim of this study was to explore the feasibility of 3D extrusion-based printing as a pharmaceutical manufacture technique for the fabrication of gastro-floating tablets. Novel low-density lattice internal structure gastro-floating tablets of dipyridamole were developed to prolong the gastric residence time in order to improve drug release rate and consequently, improve bioavailability and therapeutic efficacy. Excipients commonly employed in the pharmaceutical study could be efficiently applied in the room temperature 3D extrusion-based printing process. The tablets were designed with three kinds of infill percentage and prepared by hydroxypropyl methylcellulose (HPMC K4M) and hydroxypropyl methylcellulose (HPMC E15) as hydrophilic matrices and microcrystalline cellulose (MCC PH101) as extrusion molding agent. In vitro evaluation of the 3D printed gastro-floating tablets was performed by determining mechanical properties, content uniformity, and weight variation. Furthermore, re-floating ability, floating duration time, and drug release behavior were also evaluated. Dissolution profiles revealed the relationship between infill percentage and drug release behavior. The results of this study revealed the potential of 3D extrusion-based printing to fabricate gastro-floating tablets with more than 8h floating process with traditional pharmaceutical excipients and lattice internal structure design. Copyright © 2017. Published by Elsevier B.V.

Angiographically demonstrated coronary collaterals predict residual viable myocardium in patients with chronic myocardial infarction. A regional metabolic study

International Nuclear Information System (INIS)

Fukai, Masumi; Ii, Masaaki; Nakakoji, Takahiro

2000-01-01

Angiographical demonstration of coronary collateral circulation may suggest the presence of residual viable myocardium. The development of coronary collaterals was judged according to Rentrop's classification in 37 patients with old anteroseptal myocardial infarction and 13 control patients with chest pain syndrome. The subjects with myocardial infarction were divided into 2 groups: 17 patients with the main branch of the left coronary artery clearly identified by collateral blood flow from the contralateral coronary artery [Coll (+) group, male/female 10/7, mean age 56.6 years] and 20 patients with obscure coronary trunk [Coll (-) group, male/female 16/4, mean age 54.9 years]. Thallium-201 myocardial scintigraphy and examination of local myocardial metabolism were carried out by measuring the flux of lactic acid under dipyridamole infusion load. Coronary stenosis of 99% or total occlusion was found in only 5 of 20 patients (25%) in the Coll (-) group but in 16 of 17 patients (94%) in the Coll (+) group (p<0.001). Redistribution of myocardial scintigraphy was found in 11 of 15 patients (73%) in the Coll (+) group, but only 3 of 18 patients (17%) in the Coll (-) group (p<0.01). The myocardial lactic acid extraction rate was -13.2±17.0% in the Coll (+) group, but 9.1±13.2% in the Coll (-) group (p<0.001). These results suggest that coronary collateral may contribute to minimizing the infarct area and to prediction of the presence of viable myocardium. (author)

Detection of human collateral circulation by vasodilation-thallium-201 tomography

International Nuclear Information System (INIS)

Nienaber, C.A.; Salge, D.; Spielmann, R.P.; Montz, R.; Bleifeld, W.

1990-01-01

Coronary arteriolar vasodilation may provoke redistribution of flow to collateral-dependent jeopardized myocardium. To assess the physiologic significance of collaterals, 80 consecutive post-infarction patients (age 58 +/- 8 years) underwent vasodilation-redistribution thallium-201 tomographic imaging after administration of 0.56 mg of intravenous dipyridamole/kg body weight. Circumferential profile analysis of thallium-201 uptake and redistribution in representative left ventricular tomograms provided quantitative assessment of transient and fixed defects and separation between periinfarctional and distant inducible hypoperfusion. Tomographic perfusion data were correlated to wall motion and collateral circulation between distinct anatomic perfusion territories. Patients were grouped according to presence (59%) or absence (41%) of angiographically visible collateral channels to jeopardized myocardium. In the presence of collaterals, distant reversible defects were larger than in absence of collaterals (p less than 0.05); the extent of combined periinfarctional and distant redistribution was also larger in collateralized patients (p less than 0.025), whereas the size of the persistent perfusion defect was similar in both groups. By prospective analysis the tomographic perfusion pattern of combined periinfarctional and distant redistribution revealed a sensitivity of 85% and a specificity of 78% for the detection of significant collateral circulation in this group of patients. Thus, using the exhausted flow reserve as a diagnostic tool, vasodilation-thallium-201 tomography has the potential to identify and quantitate collateralized myocardium in post-infarction patients and may guide diagnostic and therapeutic decision-making

Response of left ventricular ejection fraction to recovery from general anesthesia: measurement by gated radionuclide angiography

International Nuclear Information System (INIS)

Coriat, P.; Mundler, O.; Bousseau, D.; Fauchet, M.; Rous, A.C.; Echter, E.; Viars, P.

1986-01-01

To test the hypothesis that, after anesthesia for noncardiac surgical procedures, the increased cardiac work during recovery induces wall motion and ejection fraction (EF) abnormalities in patients with mild angina pectoris, gated radionuclide angiography was performed in patients undergoing simple cholecystectomy under narcotic-relaxant general anesthesia. The ejection fraction was determined during anesthesia at the end of surgery, and then determined 3 min and 3 hr after extubation. A new angiography was performed 24 hr later, and a myocardial scintigraphy (Thallium 201) was performed during infusion of the coronary vasodilator, dipyridamole. In the first part of the investigation, eight patients without coronary artery disease (CAD) (group 1) and 20 patients with mild angina (group 2) were studied. In the second part of the study, seven patients (group 3) with mild angina pectoris received an intravenous infusion of 0.4 microgram X kg-1 X min-1 of nitroglycerin started before surgery and gradually decreased 4 hr after extubation. In group 1, EF remained unchanged at recovery. In contrast in group 2, EF responded abnormally to recovery: EF decreased from 55% during anesthesia to 45% 3 min after extubation (P less than 0.001). Patients in group 3, who received intravenous nitroglycerin, showed no change of EF at recovery. This study demonstrates that recovery from general anesthesia causes abnormalities in left ventricular function in patients suffering from CAD. These abnormalities are prevented by prophylactic intravenous nitroglycerin

Identification of ischemic and hibernating myocardium: feasibility of post-exercise F-18 deoxyglucose positron emission tomography

International Nuclear Information System (INIS)

Marwick, T.H.; MacIntyre, W.J.; Salcedo, E.E.; Go, R.T.; Saha, G.; Beachler, A.

1991-01-01

The identification of ischemic and hibernating myocardium facilitates the selection of patients most likely to benefit from revascularization. This study examined the feasibility of metabolic imaging, using post-exercise F-18 deoxyglucose positron emission tomography (FDG-PET) for the diagnosis of both ischemia and hibernation in 27 patients with known coronary anatomy. Normal post-exercise FDG uptake was defined in each patient by reference to normal resting perfusion and normal coronary supply. Abnormal elevation of FDG (ischemia or hibernation) was compared in 13 myocardial segments in each patient, with the results of dipyridamole stress perfusion imaging performed by rubidium-82 positron emission tomography (Rb-PET). Myocardial ischemia was diagnosed by either FDG-PET or Rb-PET in 34 segments subtended by significant local coronary stenoses. Increased FDG uptake was present in 32/34 (94%) and a reversible perfusion defect was identified by Rb-PET in 22/34 (65%, p less than .01). In 3 patients, ischemia was identified by metabolic imaging alone. In 16 patients with previous myocardial infarction, perfusion defects were present at rest in 89 regions, 30 of which (34%) demonstrated increased FDG uptake, consistent with the presence of hibernation. Increased post-exercise FDG uptake appears to be a sensitive indicator of ischemia and myocardial hibernation. Increased post-exercise FDG uptake, appears to be a sensitive indicator of ischemia and myocardial hibernation. This test may be useful in selecting post-infarction patients for revascularization

Clinical and experimental analysis of 201thallium uptake of the heart

International Nuclear Information System (INIS)

Strauer, B.E.; Buell, U.; Buerger, S.; Klinikum Grosshadern, Muenchen

1978-01-01

Studies were carried out in order to determine the factors influencing myocardial 201 Tl uptake. A total of 158 patients was examined with regard to both 201 Tl uptake and the assessment of left ventricular and coronary function. Moreover, 42 animal experiments were performed. The results demonstrate that: 1) 201 Tl uptake in the normal and hypertrophied human heart is linearly correlated with the muscle mass of the left ventricle (LVMM); 2) 201 Tl uptake is enhanced in the inner layer and is decreased in the outer layer of the left ventricular wall. The 201 Tl uptake of the right ventricle is 40% lower in comparison to the left ventricle; 3) the basic correlation between 201 Tl uptake and LVMM is influenced by alterations of both myocardial flow and myocardial oxygen consumption; and 4) inotropic interventions (isoproterenol, calcium, norepinephrine) as well as coronary dilatation (dipyridamole) may considerably augment 201 Tl uptake in accordance with changes in myocardial oxygen consumption and/or myocardial flow. It is concluded that myocardial 201 Tl uptake is determined by multiple factors. The major determinants have been shown to include muscle mass, myocardial flow and myocardial oxygen consumption. The clinical data obtained from patient groups with normal ventricular function, with coronary artery disease, with left ventricular wall motion abnormalities and with different degree of left ventricular hypertrophy are correlated with quantitated myocardial 201 Tl uptake. (orig./MG) [de

Myocardial perfusion scintigraphy in Germany. Results of the 2005 query and current status

International Nuclear Information System (INIS)

Lindner, O.; Burchert, W.; Bengel, F.M.; Zimmermann, R.; Dahl, J. vom; Schaefer, W.; Buell, U.; Schober, O.; Schwaiger, M.; Kluge, R.; Schaefers, M.

2007-01-01

The working group Cardiovascular Nuclear Medicine of the German Society of Nuclear Medicine (DGN), in cooperation with the working group Nuclear Cardiology of the German Cardiac Society (DGK), decided to conduct a national survey on myocardial perfusion scintigraphy (MPS). Method: a questionnaire to evaluate MPS for the year 2005 was sent. Results: 346 completed questionnaires had been returned (213 private practices, 99 hospitals and 33 university hospitals). MPS of 112 707 patients were reported with 110 747 stress and 95 878 rest studies. The majority (> 75%) was performed with 99m Tc-MIBI or tetrofosmin. 201 Tl stress-redistribution was used in 22 637 patients (20%). The types of stress were exercise in 78%, vasodilation with adenosine or dipyridamol in 21% and dobutamine in 1%. 99.97% of all MPS were SPECT studies. Gated SPECT was performed in 36% of the stress and in 32% of the rest studies. An attenuation correction was used in 21%. 29 institutions (8%) performed gated SPECT (stress and rest) and attenuation correction. 47% of all MPS were requested by ambulatory care cardiologists, 17% by internists, 12% by primary care physicians, 21% by hospital departments and 2% by others. Conclusion: in Germany, MPS is predominantly performed with 99m Tc-perfusion agents. The common type of stress is ergometry. Gated SPECT and attenuation correction do not yet represent standards of MPS practice in Germany, which indicates some potential of optimization. (orig.)

Prognostic Value of Normal Perfusion but Impaired Left Ventricular Function in the Diabetic Heart on Quantitative Gated Myocardial Perfusion SPECT

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Jeong, Hwanjeong; Choi, Sehun; Han, Yeonhee [Research Institute of Chonbuk National Univ. Medical School and Hospitial, Jeonju (Korea, Republic of); Lee, Dong Soo; Lee, Hoyoung; Chung, Junekey [Seoul National Univ., Seoul (Korea, Republic of)

2013-09-15

This study aimed at identifying the predictive parameters on quantitative gated myocardial perfusion single-photon emission computed tomography (QG-SPECT) in diabetic patients with normal perfusion but impaired function. Methods Among the 533 consecutive diabetic patients, 379 patients with normal perfusion on rest Tl-201/dipyridamole-stress Tc-{sup 99m} sestamibi Gated SPECT were enrolled. Patients were grouped into those with normal post-stress left ventricular function (Group I) and those with impaired function (EF <50 or impaired regional wall motion, Group II). We investigated cardiac events and cause of death by chart review and telephone interview. Survival analysis and Cox proportional hazard model analysis were performed. Between the Group I and II, cardiac events as well as chest pain symptoms, smoking, diabetic complications were significantly different (P<0.05). On survival analysis, event free survival rate in Group II was significantly lower than in Group I (P=0.016). In univariate Cox proportional hazard analysis on overall cardiac event, Group (II over I), diabetic nephropathy, summed motion score (SMS), summed systolic thickening score (STS), numbers of abnormal segmental wall motion and systolic thickening predicted more cardiac events (P<0.05). Multivariate analysis showed that STS was the only independent predictor cardiac event. The functional parameter, especially summed systolic thickening score on QG-SPECT had prognostic values, despite normal perfusion, in predicting cardiac events in diabetic patients, and QG-SPECT provides clinically useful risk stratification in diabetic patients with normal perfusion.

A polychromatic turbidity microplate assay to distinguish discovery stage drug molecules with beneficial precipitation properties.

Science.gov (United States)

Morrison, John; Nophsker, Michelle; Elzinga, Paul; Donoso, Maria; Park, Hyunsoo; Haskell, Roy

2017-10-05

A material sparing microplate screening assay was developed to evaluate and compare the precipitation of discovery stage drug molecules as a function of time, concentration and media composition. Polychromatic turbidity time course profiles were collected for cinnarizine, probucol, dipyridamole as well as BMS-932481, and compared with turbidity profiles of monodisperse particle size standards. Precipitation for select sample conditions were further characterized at several time points by size, morphology, amount and form via laser diffraction, microscopy, size based particle counting and X-ray diffraction respectively. Wavelength dependent turbidity was found indicative of nanoprecipitate, while wavelength independent turbidity was consistent with larger microprecipitate formation. A transition from wavelength dependent to wavelength independent turbidity occurred for nanoparticle to microparticle growth, and a decrease in wavelength independent turbidity correlated with continued growth in size of microparticles. Other sudden changes in turbidity signal over time such as rapid fluctuation, a decrease in slope or a sharp inversion were correlated with very large or aggregated macro-precipitates exceeding 100μm in diameter, a change in the rate of precipitate formation or an amorphous to crystalline form conversion respectively. The assay provides an effective method to efficiently monitor and screen the precipitation fates of drug molecules, even during the early stages of discovery with limited amounts of available material. This capability highlights molecules with beneficial precipitation properties that are able to generate and maintain solubility enabling amorphous or nanoparticle precipitates. Copyright © 2017 Elsevier B.V. All rights reserved.

The diagnosis accuracy and safety of 99Tcm-MIBI myocardial perfusion imaging-a retrospective multicenter study

International Nuclear Information System (INIS)

Wang Rongfu; Qiu Yanli; Wang Liqin

2012-01-01

Objective: To evaluate the diagnostic accuracy and safety of 99 Tc m -MIBI MPI by retrospectively analyzing data from this multicenter study. Methods: Participating centers included six hospitals: Peking University First Hospital, Beijing Fuwai Hospital of Chinese Academy of Medical Science and Peking Union Medical College, Anzhen Hospital of Capital Medical University, Beijing Hospital of Health Ministry, Beijing Tongren Hospital of Capital Medical University and Peking University People's Hospital. According to the inclusion and exclusion criteria, 500 subjects (335 male, 165 female, mean age (60.1 ±11.1) years) who underwent MPI between April 1998 and April 2006 were enrolled. All subjects were investigated with stress/rest MPI and CAG within 1 month. Stress test was performed with bicycle ergometry or with intravenous dipyridamole, adenosine or ATP. Perfusion defects on MPI were allocated to corresponding coronary arteries. During the stress and imaging period,any discomfort or symptoms were recorded. Coronary stenosis with ≥ 50% luminal narrowing was considered significant in CAG and taken as the gold standard. 99 Tc m -MIBI MPI results for the number of stenosed vessels, stenotic severity and coronary artery allocation were compared using χ 2 test. Results: There were 280 subjects that underwent exercise stress tests and the remaining 220 received pharmacological stress tests (117 adenosine, 32 dipyridamole, 71 ATP). Two hundred and forty-nine patients had significant coronary stenosis and 251 had normal CAG. Out of the 249 patients with positive CAG results, 101 had one-vessel, 66 had two-vessel and 82 had three-vessel disease. Significant stenosis of the LAD was present in 205 patients, 144 had RCA stenosis and 130 had stenosis of the LCX. The sensitivity,specificity, accuracy, positive predictive and negative predictive values of MPI for detection of coronary artery disease were 65.1% (162/249), 81.3% (204/251), 73.2% (366/500), 77.5% (162

Inhibition of synaptically evoked cortical acetylcholine release by adenosine: an in vivo microdialysis study in the rat.

Science.gov (United States)

Materi, L M; Rasmusson, D D; Semba, K

2000-01-01

The release of cortical acetylcholine from the intracortical axonal terminals of cholinergic basal forebrain neurons is closely associated with electroencephalographic activity. One factor which may act to reduce cortical acetylcholine release and promote sleep is adenosine. Using in vivo microdialysis, we examined the effect of adenosine and selective adenosine receptor agonists and antagonists on cortical acetylcholine release evoked by electrical stimulation of the pedunculopontine tegmental nucleus in urethane anesthetized rats. All drugs were administered locally within the cortex by reverse dialysis. None of the drugs tested altered basal release of acetylcholine in the cortex. Adenosine significantly reduced evoked cortical acetylcholine efflux in a concentration-dependent manner. This was mimicked by the adenosine A(1) receptor selective agonist N(6)-cyclopentyladenosine and blocked by the selective A(1) receptor antagonist 8-cyclopentyl-1,3-dipropylxanthine (DPCPX). The A(2A) receptor agonist 2-[p-(2-carboxyethyl)-phenethylamino]-5'-N-ethylcarboxamidoadenosi ne hydrochloride (CGS 21680) did not alter evoked cortical acetylcholine release even in the presence of DPCPX. Administered alone, neither DPCPX nor the non-selective adenosine receptor antagonist caffeine affected evoked cortical acetylcholine efflux. Simultaneous delivery of the adenosine uptake inhibitors dipyridamole and S-(4-nitrobenzyl)-6-thioinosine significantly reduced evoked cortical acetylcholine release, and this effect was blocked by the simultaneous administration of caffeine. These data indicate that activation of the A(1) adenosine receptor inhibits acetylcholine release in the cortex in vivo while the A(2A) receptor does not influence acetylcholine efflux. Such inhibition of cortical acetylcholine release by adenosine may contribute to an increased propensity to sleep during prolonged wakefulness.

Diagnostic value of myocardial perfusion SPECT in the prediction of restenosis after coronary artery bypass graft surgery

International Nuclear Information System (INIS)

Paeng, J. C.; Lee, D. S.; Kang, W. J.; Kim, K. B.; Chung, J. K.; Lee, M. C.

2002-01-01

Myocardial SPECT has been reported to be sensitive in the detection of restenosis after revascularization. However, the diagnostic value is not well established in bypass graft surgery (CABG), due to significant influences of characteristics of graft vessels and the time interval between CABG and the SPECT. In this study, we evaluated the diagnostic value of myocardial SPECT for the restenosis after CABG. A total of 160 patients with coronary artery disease (M:F=118:42, 60±8 yr) who had undergone CABG were included. Rest T1-201/ dipyridamole stress Tc-99m-MIBI SPECT was performed 3 months (103±16 days) after CABG. Segmental perfusion was quantified using a 20-segment model, and segments of reversible perfusion defect (REV) were defined. Follow-up coronary angiography was performed 1 year (397±104 days) after CABG. The segments of REV were compared between arterial and venous graft groups. And the diagnostic power of 3-month SPECT was evaluated for the prediction of restenosis. On the 3-month SPECT, 620 segments showed REV. The segments of REV were 37% of artery-grafted segments and 36% of vein-grafted segments (p=n.s.). On 1-year coronary angiography, 113 graft vessels (28%) showed restenosis. The overall sensitivity and specificity of REV on 3-month SPECT for the prediction of restenosis were 46% and 67%, respectively, but 52% and 68%, in artery-graft group. REV detected on 3-month SPECT has a predictive value, especially, high specificity for the prediction of restenosis after CABG, which was more definite in artery-graft group

Short-term effects of an anti-inflammatory treatment on clinical parameters and serum levels of C-reactive protein and proinflammatory cytokines in subjects with periodontitis.

Science.gov (United States)

Renvert, Stefan; Lindahl, Christel; Roos-Jansåker, Ann-Marie; Lessem, Jan

2009-06-01

Periodontal disease is the most common multifactorial disease, afflicting a very large proportion of the adult population. Periodontal disease secondarily causes increases in the serum levels of C-reactive protein (CRP) and other markers of inflammation. An increased level of CRP reflects an increased risk for cardiovascular disease. The aim of the current randomized clinical trial was to evaluate the short-term effect of a combination of dipyridamole and prednisolone (CRx-102) on the levels of high-sensitivity (hs)-CRP, proinflammatory markers in blood, and clinical signs of periodontal disease. Fifty-seven patients with >/=10 pockets with probing depths >/=5 mm were randomized into two groups in this masked single-center placebo-controlled study: CRx-102 (n = 28) and placebo (n = 29). hs-CRP levels, inflammatory markers (interleukin [IL]-6, -1beta, -8, and -12, tumor necrosis factor-alpha, and interferon-gamma [IFN-gamma]), bleeding on probing (BOP), and changes in probing depths were evaluated. The subjects received mechanical non-surgical therapy after 42 days, and the study was completed after 49 days. At day 42, the differences in the hs-CRP, IFN-gamma, and IL-6 levels between the two groups were statistically significant (P <0.05), whereas no difference was found for the other inflammatory markers. There was no change in probing depth or BOP between the two groups. The administration of CRx-102 resulted in significant decreases in hs-CRP, IFN-gamma, and IL-6, but it did not significantly change BOP or probing depths.

Hypoxia activates a Ca2+-permeable cation conductance sensitive to carbon monoxide and to GsMTx-4 in human and mouse sickle erythrocytes.

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Vandorpe, David H; Xu, Chang; Shmukler, Boris E; Otterbein, Leo E; Trudel, Marie; Sachs, Frederick; Gottlieb, Philip A; Brugnara, Carlo; Alper, Seth L

2010-01-15

Deoxygenation of sickle erythrocytes activates a cation permeability of unknown molecular identity (Psickle), leading to elevated intracellular [Ca(2+)] ([Ca(2+)](i)) and subsequent activation of K(Ca) 3.1. The resulting erythrocyte volume decrease elevates intracellular hemoglobin S (HbSS) concentration, accelerates deoxygenation-induced HbSS polymerization, and increases the likelihood of cell sickling. Deoxygenation-induced currents sharing some properties of Psickle have been recorded from sickle erythrocytes in whole cell configuration. We now show by cell-attached and nystatin-permeabilized patch clamp recording from sickle erythrocytes of mouse and human that deoxygenation reversibly activates a Ca(2+)- and cation-permeable conductance sensitive to inhibition by Grammastola spatulata mechanotoxin-4 (GsMTx-4; 1 microM), dipyridamole (100 microM), DIDS (100 microM), and carbon monoxide (25 ppm pretreatment). Deoxygenation also elevates sickle erythrocyte [Ca(2+)](i), in a manner similarly inhibited by GsMTx-4 and by carbon monoxide. Normal human and mouse erythrocytes do not exhibit these responses to deoxygenation. Deoxygenation-induced elevation of [Ca(2+)](i) in mouse sickle erythrocytes did not require KCa3.1 activity. The electrophysiological and fluorimetric data provide compelling evidence in sickle erythrocytes of mouse and human for a deoxygenation-induced, reversible, Ca(2+)-permeable cation conductance blocked by inhibition of HbSS polymerization and by an inhibitor of strctch-activated cation channels. This cation permeability pathway is likely an important source of intracellular Ca(2+) for pathologic activation of KCa3.1 in sickle erythrocytes. Blockade of this pathway represents a novel therapeutic approach for treatment of sickle disease.

Hypoxia activates a Ca2+-permeable cation conductance sensitive to carbon monoxide and to GsMTx-4 in human and mouse sickle erythrocytes.

Directory of Open Access Journals (Sweden)

David H Vandorpe

2010-01-01

Full Text Available Deoxygenation of sickle erythrocytes activates a cation permeability of unknown molecular identity (Psickle, leading to elevated intracellular [Ca(2+] ([Ca(2+](i and subsequent activation of K(Ca 3.1. The resulting erythrocyte volume decrease elevates intracellular hemoglobin S (HbSS concentration, accelerates deoxygenation-induced HbSS polymerization, and increases the likelihood of cell sickling. Deoxygenation-induced currents sharing some properties of Psickle have been recorded from sickle erythrocytes in whole cell configuration.We now show by cell-attached and nystatin-permeabilized patch clamp recording from sickle erythrocytes of mouse and human that deoxygenation reversibly activates a Ca(2+- and cation-permeable conductance sensitive to inhibition by Grammastola spatulata mechanotoxin-4 (GsMTx-4; 1 microM, dipyridamole (100 microM, DIDS (100 microM, and carbon monoxide (25 ppm pretreatment. Deoxygenation also elevates sickle erythrocyte [Ca(2+](i, in a manner similarly inhibited by GsMTx-4 and by carbon monoxide. Normal human and mouse erythrocytes do not exhibit these responses to deoxygenation. Deoxygenation-induced elevation of [Ca(2+](i in mouse sickle erythrocytes did not require KCa3.1 activity.The electrophysiological and fluorimetric data provide compelling evidence in sickle erythrocytes of mouse and human for a deoxygenation-induced, reversible, Ca(2+-permeable cation conductance blocked by inhibition of HbSS polymerization and by an inhibitor of strctch-activated cation channels. This cation permeability pathway is likely an important source of intracellular Ca(2+ for pathologic activation of KCa3.1 in sickle erythrocytes. Blockade of this pathway represents a novel therapeutic approach for treatment of sickle disease.

Relations among impaired coronary flow reserve, left ventricular hypertrophy and thallium perfusion defects in hypertensive patients without obstructive coronary artery disease

International Nuclear Information System (INIS)

Houghton, J.L.; Frank, M.J.; Carr, A.A.; von Dohlen, T.W.; Prisant, L.M.

1990-01-01

Invasive Doppler catheter-derived coronary flow reserve, echocardiographic measurements of left ventricular hypertrophy and intravenous dipyridamole-limited stress thallium-201 scintigraphy were compared in 48 patients (40 were hypertensive or diabetic) with clinical ischemic heart disease and no or minor coronary artery disease. Abnormal vasodilator reserve (ratio less than 3:1) occurred in 50% of the study group and markedly abnormal reserve (less than or equal to 2:1) occurred in 27%. Coronary vasodilator reserve was significantly lower (2.2 +/- 0.8 versus 3.5 +/- 1.3, p = 0.003) and indexed left ventricular mass significantly higher (152.6 +/- 42.2 versus 113.6 +/- 24.0 g, p = 0.0007) in patients with a positive (n = 11) versus a negative (n = 32) thallium perfusion scan. Coronary flow reserve was linearly related in coronary basal flow velocity as follows: y = -0.17x + 4.59; r = -0.57; p = 0.00002. The decrement in flow reserve was not linearly related to the degree of left ventricular hypertrophy. Abnormal vasodilator reserve subsets found in hypertensive patients were defined on the basis of basal flow velocity, indexed left ventricular mass and clinical factors. In this series, diabetes did not cause a detectable additional decrement in flow reserve above that found with hypertension alone. These findings demonstrate that thallium perfusion defects are associated with depressed coronary vasodilator reserve in hypertensive patients without obstructive coronary artery disease. Left ventricular hypertrophy by indexed mass criteria is predictive of which hypertensive patients are likely to have thallium defects

Ventricular distension and diastolic coronary blood flow in the anaesthetized dog.

Science.gov (United States)

Gattullo, D; Linden, R J; Losano, G; Pagliaro, P; Westerhof, N

1993-01-01

There appears to be no agreement as to whether or not an increase in diastolic left ventricular pressure and/or volume can cause a decrease in diastolic coronary blood flow. We investigated the problem in the anaesthetized dog using a flaccid freely distensible latex balloon inserted into the left ventricle with the animal on extracorporeal circulation and the coronary perfusion pressure constant at about 45 mm Hg. Maximal vasodilatation and suppression of autoregulation in coronary vasculature was obtained by the intracoronary infusion of dipyridamole (10-40 mg/h). Ventricular volume was changed in steps of 10 ml from 10 to 70 ml and back to 10 ml, whilst recording coronary blood flow and left ventricular pressure in the left circumflex coronary artery. Over a range of ventricular volumes from 20 to 50 ml and a concomitant rise in diastolic ventricular pressure to about 20 mm Hg there was no change in the diastolic coronary flow. Only when the ventricular volume was more than two times the control value (i.e. exceeded 50 ml) and left ventricular pressure was more than 20 mm Hg, was there a decrease in coronary flow. During the return of the volume to the control level there was a fall in diastolic flow and ventricular contractility with respect to the values obtained when the volume was increased; these two effects were transient lasting less than 10 min. It was not considered that any of the three models of the coronary circulation, waterfall, intramyocardial pump or varying elastance model could explain our results.(ABSTRACT TRUNCATED AT 250 WORDS)

Injuries to the vascular endothelium: vascular wall and endothelial dysfunction.

Science.gov (United States)

Fisher, Mark

2008-01-01

Vascular endothelial injury has multiple elements, and this article focuses on ischemia-related processes that have particular relevance to ischemic stroke. Distinctions between necrotic and apoptotic cell death provide a basic science context in which to better understand the significance of classical core and penumbra concepts of acute stroke, with apoptotic processes particularly prominent in the penumbra. The mitochondria are understood to serve as a reservoir of proteins that mediate apoptosis. Oxidative stress pathways generating reactive oxygen species (ROS) are prominent in endothelial injury, both ischemic and nonischemic, with prominent roles of enzyme- and nonenzymemediated pathways; mitochondria once again have a critical role, particularly in the nonenzymatic pathways generating ROS. Inflammation also contributes to vascular endothelial injury, and endothelial cells have the capacity to rapidly increase expression of inflammatory mediators following ischemic challenge; this leads to enhanced leukocyte-endothelial interactions mediated by selectins and adhesion molecules. Preconditioning consists of a minor version of an injurious event, which in turn may protect vascular endothelium from injury following a more substantial event. Presence of the blood-brain barrier creates unique responses to endothelial injury, with permeability changes due to impairment of endothelial-matrix interactions compounding altered vasomotor tone and tissue perfusion mediated by nitric oxide. Pharmacological protection against vascular endothelial injury can be provided by several of the phosphodiesterases (cilostazol and dipyridamole), along with statins. Optimal clinical responses for protection of brain vascular endothelium may use preconditioning as a model, and will likely require combined protection against apoptosis, ROS, and inflammation.

Measurement of plasma adenosine concentration: methodological and physiological considerations

International Nuclear Information System (INIS)

Gewirtz, H.; Brown, P.; Most, A.S.

1987-01-01

This study tested the hypothesis that measurements of plasma adenosine concentration made on samples of blood obtained in dipyridamole and EHNA (i.e., stopping solution) may be falsely elevated as a result of ongoing in vitro production and accumulation of adenosine during sample processing. Studies were performed with samples of anticoagulated blood obtained from anesthesized domestic swine. Adenosine concentration of ultra filtrated plasma was determined by HPLC. The following parameters were evaluated: (i) rate of clearance of [ 3 H]adenosine added to plasma, (ii) endogenous adenosine concentration of matched blood samples obtained in stopping solution alone, stopping solution plus EDTA, and perchloric acid (PCA), (iii) plasma and erythrocyte endogenous adenosine concentration in nonhemolyzed samples, and (iv) plasma adenosine concentration of samples hemolyzed in the presence of stopping solution alone or stopping solution plus EDTA. We observed that (i) greater than or equal to 95% of [ 3 H]adenosine added to plasma is removed from it by formed elements of the blood in less than 20 s, (ii) plasma adenosine concentration of samples obtained in stopping solution alone is generally 10-fold greater than that of matched samples obtained in stopping solution plus EDTA, (iii) deliberate mechanical hemolysis of blood samples obtained in stopping solution alone resulted in substantial augmentation of plasma adenosine levels in comparison with matched nonhemolyzed specimens--addition of EDTA to stopping solution prevented this, and (iv) adenosine content of blood samples obtained in PCA agreed closely with the sum of plasma and erythrocyte adenosine content of samples obtained in stopping solution plus EDTA

Comparison between fragmented QRS and Q waves in myocardial scar detection using myocardial perfusion single photon emission computed tomography.

Science.gov (United States)

Dabbagh Kakhki, Vahid Reza; Ayati, Narjess; Zakavi, Seyed Rasoul; Sadeghi, Ramin; Tayyebi, Mohammad; Shariati, Farzaneh

2015-01-01

Accurate diagnosis of myocardial infarction (MI) is of paramount importance in patient management, which necessitates the development of efficient and accurate diagnostic methods. Q wave is not present in all patients with MI, and its prevalence is declining. Recently, fragmented QRS (fQRS) complex has been introduced as a marker of prior MI. To investigate diagnostic value of fQRS compared to Q wave. We included 500 consecutive patients with known or suspected coronary artery disease who underwent two days of gated myocardial perfusion imaging using dipyridamole pharmacologic stress. Electrocardiogram (ECG) was evaluated to detect fQRS as well as Q-wave. Finally, subjects were compared in terms of ventricular perfusion and function indices. A total of 207 men and 269 women with mean age of 57.06 ± 12 years were studied. ECG analysis showed that 14.3% of the patients had both fQRS and Q waves, 30.7% had fQRS, and 3.8% had Q waves. Fixed myocardial perfusion defect was noted in 22.3% of patients according to MPIs. Sensitivity, specificity, and positive and negative predictive values for myocardial scar detection were 78%, 65%, 39%, and 91%, respectively, for fQRS and 61%, 94%, 76%, and 89%, respectively, for Q wave. Although fQRS had lower specificity compared to Q wave in the detection of myocardial scar, due to higher sensitivity and negative predictive value can be an invaluable diagnostic index. There is also an incremental value for fQRS in association with Q-wave in myocardial scar assessment.

The difference in association between aspirin use and other thrombocyte aggregation inhibitors and survival in patients with colorectal cancer.

Science.gov (United States)

Frouws, M A; Rademaker, E; Bastiaannet, E; van Herk-Sukel, M P P; Lemmens, V E; Van de Velde, C J H; Portielje, J E A; Liefers, G J

2017-05-01

Several studies have suggested that the association between aspirin and improved cancer survival is mediated through the mechanism of aspirin as thrombocyte aggregation inhibitors (TAI). The aim of this study was to provide epidemiological evidence for this mechanism assessing the association between overall survival and the use of aspirin and non-aspirin TAI in patients with colorectal cancer. In this observational study, data from the Netherlands Comprehensive Cancer Organisation were linked to PHARMO Database Network. Patients using aspirin or aspirin in combination with non-aspirin TAI (dual users) were selected and compared with non-users. The association between overall survival and the use of (non-)aspirin TAI was analysed using Cox regression models with the use of (non-)aspirin TAI as a time-varying covariate. In total, 9196 patients were identified with colorectal cancer and 1766 patients used TAI after diagnosis. Non-aspirin TAI were mostly clopidogrel and dipyridamole. Aspirin use was associated with a significant increased overall survival and hazard ratio (HR) 0.41 (95% confidence interval [CI] 0.37-0.47), and the use of non-aspirin TAI was not associated with survival of HR 0.92 (95% CI 0.70-1.22). Dual users did not have an improved overall survival when compared with patients using solely aspirin. Aspirin use after diagnosis of colorectal cancer was associated with significantly lower mortality rates and this effect remained significant after adjusting for potential confounders. No additional survival benefit was observed in patients using both aspirin and another TAI. Copyright © 2017 Elsevier Ltd. All rights reserved.

Prediction of wall motion improvement after coronary revascularization in patients with postmyocardial infarction. Diagnostic value of dobutamine stress echocardiography and myocardial contrast echocardiography

International Nuclear Information System (INIS)

Waku, Sachiko; Ohkubo, Tomoyuki; Takada, Kiyoshi; Ishihara, Tadashi; Ohsawa, Nakaaki; Adachi, Itaru; Narabayashi, Isamu

1997-01-01

The diagnostic value of dobutamine stress echocardiography, myocardial contrast echocardiography and dipyridamole stress thallium-201 single photon emission computed tomography (SPECT) for predicting recovery of wall motion abnormality after revascularization was evaluated in 13 patients with postmyocardial infarction. Seventeen segments showed severe wall motion abnormalities before revascularization. Nine segments which had relatively good Tl uptake on delayed SPECT images despite severely abnormal wall motion were opacified during myocardial contrast echocardiography, and showed improved wall motion after revascularization. In contrast, three segments which had poor Tl uptake and severely abnormal wall motion were not opacified during myocardial contrast echocardiography, and showed no improvement in wall motion during dobutamine stress echocardiography and after revascularization. The following three findings were assumed to be signs of myocardial viability: good Tl uptake on delayed SPECT images, improved wall motion by dobutamine stress echocardiography, and positive opacification of the myocardium by myocardiai contrast echocardiography. Myocardial contrast echocardiography had the highest sensitivity (100%) and negative predictive value (100%). Delayed SPECT images had the highest specificity (100%) and positive predictive value (100%). Dobutamine stress echocardiography had a sensitivity of 83.0%, specificity of 80.0%, positive predictive value of 90.9%, and negative predictive value of 66.7%, respectively. Myocardial contrast echocardiography showed the lowest specificity (60.0%). The techniques of dobutamine stress echocardiography and SPECT, though noninvasive, may underestimate wall motion improvement after revascularization. Further examination by myocardial contrast echocardiography is recommended to assess myocardial viability for determining the indications for coronary revascularization in spite of its invasiveness. (author)

Pharmacological Activity and Clinical Use of PDRN

Science.gov (United States)

Squadrito, Francesco; Bitto, Alessandra; Irrera, Natasha; Pizzino, Gabriele; Pallio, Giovanni; Minutoli, Letteria; Altavilla, Domenica

2017-01-01

PDRN is a proprietary and registered drug that possesses several activities: tissue repairing, anti-ischemic, and anti-inflammatory. These therapeutic properties suggest its use in regenerative medicine and in diabetic foot ulcers. PDRN holds a mixture of deoxyribonucleotides with molecular weights ranging between 50 and 1,500 KDa, it is derived from a controlled purification and sterilization process of Oncorhynchus mykiss (Salmon Trout) or Oncorhynchus keta (Chum Salmon) sperm DNA. The procedure guarantees the absence of active protein and peptides that may cause immune reactions. In vitro and in vivo experiments have suggested that PDRN most relevant mechanism of action is the engagement of adenosine A2A receptors. Besides engaging the A2A receptor, PDRN offers nucleosides and nucleotides for the so called “salvage pathway.” The binding to adenosine A2A receptors is a unique property of PDRN and seems to be linked to DNA origin, molecular weight and manufacturing process. In this context, PDRN represents a new advancement in the pharmacotherapy. In fact adenosine and dipyridamole are non-selective activators of adenosine receptors and they may cause unwanted side effects; while regadenoson, the only other A2A receptor agonist available, has been approved by the FDA as a pharmacological stress agent in myocardial perfusion imaging. Finally, defibrotide, another drug composed by a mixture of oligonucleotides, has different molecular weight, a DNA of different origin and does not share the same wound healing stimulating effects of PDRN. The present review analyses the more relevant experimental and clinical evidences carried out to characterize PDRN therapeutic effects. PMID:28491036

Optimally Repeatable Kinetic Model Variant for Myocardial Blood Flow Measurements with 82Rb PET

Directory of Open Access Journals (Sweden)

Adrian F. Ocneanu

2017-01-01

Full Text Available Purpose. Myocardial blood flow (MBF quantification with Rb82 positron emission tomography (PET is gaining clinical adoption, but improvements in precision are desired. This study aims to identify analysis variants producing the most repeatable MBF measures. Methods. 12 volunteers underwent same-day test-retest rest and dipyridamole stress imaging with dynamic Rb82 PET, from which MBF was quantified using 1-tissue-compartment kinetic model variants: (1 blood-pool versus uptake region sampled input function (Blood/Uptake-ROI, (2 dual spillover correction (SOC-On/Off, (3 right blood correction (RBC-On/Off, (4 arterial blood transit delay (Delay-On/Off, and (5 distribution volume (DV constraint (Global/Regional-DV. Repeatability of MBF, stress/rest myocardial flow reserve (MFR, and stress/rest MBF difference (ΔMBF was assessed using nonparametric reproducibility coefficients (RPCnp = 1.45 × interquartile range. Results. MBF using SOC-On, RVBC-Off, Blood-ROI, Global-DV, and Delay-Off was most repeatable for combined rest and stress: RPCnp = 0.21 mL/min/g (15.8%. Corresponding MFR and ΔMBF RPCnp were 0.42 (20.2% and 0.24 mL/min/g (23.5%. MBF repeatability improved with SOC-On at stress (p<0.001 and tended to improve with RBC-Off at both rest and stress (p<0.08. DV and ROI did not significantly influence repeatability. The Delay-On model was overdetermined and did not reliably converge. Conclusion. MBF and MFR test-retest repeatability were the best with dual spillover correction, left atrium blood input function, and global DV.

Suppressive effect of AMP-activated protein kinase on the epithelial-mesenchymal transition in retinal pigment epithelial cells.

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Ryo Matoba

Full Text Available The epithelial-mesenchymal transition (EMT in retinal pigment epithelial (RPE cells plays a central role in the development of proliferative vitreoretinopathy (PVR. The purpose of this study was to investigate the effect of AMP-activated protein kinase (AMPK, a key regulator of energy homeostasis, on the EMT in RPE cells. In this study, EMT-associated formation of cellular aggregates was induced by co-stimulation of cultured ARPE-19 cells with tumor necrosis factor (TNF-α (10 ng/ml and transforming growth factor (TGF-β2 (5 ng/ml. 5-Aminoimidazole-4-carboxamide-1-β-D-ribofuranoside (AICAR, a potent activator of AMPK, significantly suppressed TNF-α and TGF-β2-induced cellular aggregate formation (p < 0.01. Dipyridamole almost completely reversed the suppressive effect of AICAR, whereas 5'-amino-5'-deoxyadenosine restored aggregate formation by approximately 50%. AICAR suppressed the downregulation of E-cadherin and the upregulation of fibronectin and α-smooth muscle actin by TNF-α and TGF-β2. The levels of matrix metalloproteinase (MMP-2, MMP-9, interleukin-6, and vascular endothelial growth factor were significantly decreased by AICAR. Activation of the mitogen-activated protein kinase and mammalian target of rapamycin pathways, but not the Smad pathway, was inhibited by AICAR. These findings indicate that AICAR suppresses the EMT in RPE cells at least partially via activation of AMPK. AMPK is a potential target molecule for the prevention and treatment of PVR, so AICAR may be a promising candidate for PVR therapy.

Assessment of coronary artery disease with nicorandil stress magnetic resonance imaging

International Nuclear Information System (INIS)

Kawase, Yoshio; Nichimoto, Masaki; Hato, Katsunori; Okajima, Kazue; Yoshikawa, Junichi

2004-01-01

Although dipyridamole and adenosine have been used as vasodilator agents, we believe they are inadequate for vasodilator perfusion magnetic resonance imaging, due to adverse effects (flushing, warmth, headaches, and arrhythmia). Nicorandil, a potassium channel opener, has been reported to increase coronary blood flow and it was associated with fewer adverse effects than adenosine or dipiridamole. We set out to investigate whether the coronary artery stenosis could be assessed by nicorandil stress perfusion magnetic resonance imaging. First-pass contrast-enhanced magnetic resonance images of the left ventricle acquired from 50 patients at rest and during intravenous administration of nicorandil using multi-slice turbo field echo with multi shot echo-planar-imaging. Coronary angiography was performed within 1 week. There was no adverse effects during nicorandil stress in any patients. The overall sensitivity and specificity of magnetic resonance imaging in identifying patients with significant stenosis of at least one coronary artery were 93.9% (31 of 33 patients) and 94.1% (16 of 17 patients), respectively. The sensitivity of magnetic resonance imaging for detecting significant stenosis in the left anterior descending artery was 87.5%; the sensitivity in the left circumflex artery was 80%; the sensitivity in the right coronary artery was 92.3%. Similar sensitivities were observed for all 3 vascular regions, indicating that all myocardial segments were visualized with similar image quality. The present study shows that nicorandil stress perfusion magnetic resonance imaging is a safe, feasible technique for assessing coronary artery stenosis severity in a totally-noninvasive manner. (authors)

Cyanotic Congenital Heart Disease The Coronary Arterial Circulation

Science.gov (United States)

Perloff, Joseph K

2012-01-01

Background: The coronary circulation in cyanotic congenital heart disease (CCHD) includes the extramural coronary arteries, basal coronary blood flow, flow reserve, the coronary microcirculation, and coronary atherogenesis. Methods: Coronary arteriograms were analyzed in 59 adults with CCHD. Dilated extramural coronaries were examined histologically in six patients. Basal coronary blood flow was determined with N-13 positron emission tomography in 14 patients and in 10 controls. Hyperemic flow was induced by intravenous dipyridamole pharmacologic stress. Immunostaining against SM alpha-actin permitted microcirculatory morphometric analysis. Non-fasting total cholesterols were retrieved in 279 patients divided into four groups: Group A---143 cyanotic unoperated, Group B---47 rendered acyanotic by reparative surgery, Group C---41 acyanotic unoperated, Group D---48 acyanotic before and after operation. Results: Extramural coronary arteries were mildly or moderately dilated to ectatic in 49/59 angiograms. Histologic examination disclosed loss of medial smooth muscle, increased medial collagen, and duplication of internal elastic lamina. Basal coronary flow was appreciably increased. Hyperemic flow was comparable to controls. Remodeling of the microcirculation was based upon coronary arteriolar length, volume and surface densities. Coronary atherosclerosis was absent in both the arteriograms and the necropsy specimens. Conclusions: Extramural coronary arteries in CCHD dilate in response to endothelial vasodilator substances supplemented by mural attenuation caused by medial abnormalities. Basal coronary flow was appreciably increased, but hyperemic flow was normal. Remodeling of the microcirculation was responsible for preservation of flow reserve. The coronaries were atheroma-free because of the salutory effects of hypocholesterolemia, hypoxemia, upregulated nitric oxide, low platelet counts, and hyperbilirubinrmia. PMID:22845810

Numerical simulation of hot-melt extrusion processes for amorphous solid dispersions using model-based melt viscosity.

Science.gov (United States)

Bochmann, Esther S; Steffens, Kristina E; Gryczke, Andreas; Wagner, Karl G

2018-03-01

Simulation of HME processes is a valuable tool for increased process understanding and ease of scale-up. However, the experimental determination of all required input parameters is tedious, namely the melt rheology of the amorphous solid dispersion (ASD) in question. Hence, a procedure to simplify the application of hot-melt extrusion (HME) simulation for forming amorphous solid dispersions (ASD) is presented. The commercial 1D simulation software Ludovic ® was used to conduct (i) simulations using a full experimental data set of all input variables including melt rheology and (ii) simulations using model-based melt viscosity data based on the ASDs glass transition and the physical properties of polymeric matrix only. Both types of HME computation were further compared to experimental HME results. Variation in physical properties (e.g. heat capacity, density) and several process characteristics of HME (residence time distribution, energy consumption) among the simulations and experiments were evaluated. The model-based melt viscosity was calculated by using the glass transition temperature (T g ) of the investigated blend and the melt viscosity of the polymeric matrix by means of a T g -viscosity correlation. The results of measured melt viscosity and model-based melt viscosity were similar with only few exceptions, leading to similar HME simulation outcomes. At the end, the experimental effort prior to HME simulation could be minimized and the procedure enables a good starting point for rational development of ASDs by means of HME. As model excipients, Vinylpyrrolidone-vinyl acetate copolymer (COP) in combination with various APIs (carbamazepine, dipyridamole, indomethacin, and ibuprofen) or polyethylene glycol (PEG 1500) as plasticizer were used to form the ASDs. Copyright © 2017 Elsevier B.V. All rights reserved.

Activation of adenosine receptors and inhibition of cyclooxygenases: two recent pharmacological approaches to modulation of radiation suppressed hematopoiesis

International Nuclear Information System (INIS)

Hofer, M.; Pospisil, M.; Vacek, A.; Hola, J.; Weiterova, L.; Streitova, D.; Znojil, V.

2008-01-01

Searching for drugs conforming to requirements for protection and/or treatment of radiation-induced damage belongs to the most important tasks of current radiobiology. In the Laboratory of Experimental Hematology, Institute of Biophysics, v.v.i., Academy of Sciences of the Czech Republic, Brno, Czech Republic, two original approaches for stimulation of radiation-suppressed hematopoiesis have been tested in recent years, namely activation of adenosine receptors and inhibition of cyclooxygenases. Non-selective activation of adenosine receptors, induced by combined administration of dipyridamole, a drug preventing adenosine uptake and supporting thus its extracellular receptor-mediated action, and adenosine monophosphate, an adenosine prodrug, has been found to stimulate hematopoiesis when the drugs were given either pre- or post-irradiation. When synthetic adenosine receptor agonists selective for individual adenosine receptor subtypes were tested, stimulatory effects in myelosuppressed mice have been found after administration of IB-MECA, a selective adenosine A3 receptor agonist. Non-selective cyclooxygenase inhibitors, inhibiting both cyclooxygenase-1 (COX-1) and cyclooxygenase-2 (COX-2), indomethacin, diclofenac, or flurbiprofen, have been observed to act positively on radiation-perturbed hematopoiesis in sublethally irradiated mice. However, their undesirable gastrointestinal side effects have been found to negatively influence survival of lethally irradiated animals. Recently tested selective COX-2 inhibitor meloxicam, preserving protective action of COX-1-synthesized prostaglandins in the gastrointestinal tissues, has been observed to retain the hematopoiesis-stimulating effects of non-selective cyclooxygenase inhibitors and to improve the survival of animals exposed to lethal radiation doses. These findings bear evidence for the possibility to use selective adenosine A3 receptor agonists and selective COX-2 inhibitors in human practice for treatment of

A Lower Temperature FDM 3D Printing for the Manufacture of Patient-Specific Immediate Release Tablets.

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Okwuosa, Tochukwu C; Stefaniak, Dominika; Arafat, Basel; Isreb, Abdullah; Wan, Ka-Wai; Alhnan, Mohamed A

2016-11-01

The fabrication of ready-to-use immediate release tablets via 3D printing provides a powerful tool to on-demand individualization of dosage form. This work aims to adapt a widely used pharmaceutical grade polymer, polyvinylpyrrolidone (PVP), for instant on-demand production of immediate release tablets via FDM 3D printing. Dipyridamole or theophylline loaded filaments were produced via processing a physical mixture of API (10%) and PVP in the presence of plasticizer through hot-melt extrusion (HME). Computer software was utilized to design a caplet-shaped tablet. The surface morphology of the printed tablet was assessed using scanning electron microscopy (SEM). The physical form of the drugs and its integrity following an FDM 3D printing were assessed using x-ray powder diffractometry (XRPD), thermal analysis and HPLC. In vitro drug release studies for all 3D printed tablets were conducted in a USP II dissolution apparatus. Bridging 3D printing process with HME in the presence of a thermostable filler, talc, enabled the fabrication of immediate release tablets at temperatures as low as 110°C. The integrity of two model drugs was maintained following HME and FDM 3D printing. XRPD indicated that a portion of the loaded theophylline remained crystalline in the tablet. The fabricated tablets demonstrated excellent mechanical properties, acceptable in-batch variability and an immediate in vitro release pattern. Combining the advantages of PVP as an impeding polymer with FDM 3D printing at low temperatures, this approach holds a potential in expanding the spectrum of drugs that could be used in FDM 3D printing for on demand manufacturing of individualised dosage forms.

Significance of abnormal myocardial perfusion scintigraphy in young adult patients with SLE

International Nuclear Information System (INIS)

Zakavi, S.R.; Kakhki, V.R.D.; Sadeghi, R.; Jokar, M.H.; Khazaei, G.

2009-01-01

Detection of subclinical coronary artery disease (CAD) is a potential challenge in patients with systemic lupus erythematosus (SLE) and it is suggested that myocardial perfusion single photon emission computerized tomography (SPECT) is more sensitive than exercise test in this setting. However, the significance of perfusion abnormalities in SLE patients is not well known. In this study, we evaluated the prognostic significance of myocardial perfusion defects in patients with SLE. Patients with proven diagnosis of SLE admitted to the hospital due to noncardiac problems with no history of CAD were studied. All patients underwent 99m Tc-methoxyisobutylisonitrile (MIBI) myocardial perfusion scan using dipyridamole as pharmacological stress. All patients were followed up by reviewing patients file in lupus clinic and any minor or major cardiac events were recorded. Eighteen female and two male patients with mean age of 28.2±12.05 years were included. Six patients had mild reversible perfusion defects with mean summed difference score of 2.5±1.0. Pattern of reverse redistribution (reverse fill-in) was noted in three patients. Eleven patients had normal myocardial perfusion. Hypokinesia was noted in three patients on gated images. One patient with abnormal perfusion died 21 days after imaging due to on-cardiac cause. Nineteen patients were followed for a mean time of 39.2±16.0 months. No major or minor cardiac events were noted during follow-up. Three patients (one with abnormal perfusion) had at least one readmission during follow-up period. Our study showed that myocardial perfusion abnormalities are fairly frequent in SLE patients but the defects are generally mild and do not advocate an adverse prognosis. (author)

Epigenetics and Vasculitis: a Comprehensive Review.

Science.gov (United States)

Renauer, Paul; Coit, Patrick; Sawalha, Amr H

2016-06-01

Vasculitides represent a group of relatively rare systemic inflammatory diseases of the blood vessels. Despite recent progress in understanding the genetic basis and the underlying pathogenic mechanisms in vasculitis, the etiology and pathogenesis of vasculitis remain incompletely understood. Epigenetic dysregulation plays an important role in immune-mediated diseases, and the contribution of epigenetic aberrancies in vasculitis is increasingly being recognized. Histone modifications in the PR3 and MPO gene loci might be mechanistically involved in the pathogenesis of anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis. Similarly, other studies revealed important epigenetic contribution to other vasculitides, including Kawasaki disease and IgA vasculitis. More recently, genome-wide epigenomic studies have been performed in several vasculitides. A recent genome-wide DNA methylation study uncovered an important role for epigenetic remodeling of cytoskeleton-related genes in the pathogenesis of Behçet's disease and suggested that reversal of some of these DNA methylation changes associates with disease remission. Genome-wide DNA methylation profiling characterized the inflammatory response in temporal artery tissue from patients with giant cell arteritis and showed increased activation of calcineurin/nuclear factor of activated T cells (NFAT) signaling, prompting the suggestion that a specific calcineurin/NFAT inhibitor that is well tolerated and with the added beneficial anti-platelet activity, such as dipyridamole, might be of therapeutic potential in giant cell arteritis. While epigenetic studies in systemic vasculitis are still in their infancy, currently available data clearly indicate that investigating the epigenetic mechanisms underlying these diseases will help to better understand the pathogenesis of vasculitis and provide novel targets for the development of disease biomarkers and new therapies.

Myocardial perfusion scintigraphy 2007 in Germany. Results of the query and current status

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Lindner, O. [Inst. fuer Radiologie, Nuklearmedizin und Molekulare Bildgebung, Herz- und Diabeteszentrum NRW, Bad Oeynhausen (Germany); Burchert, W. [Inst. fuer Radiologie, Nuklearmedizin und Molekulare Bildgebung, Herz- und Diabeteszentrum NRW, Bad Oeynhausen (Germany); Arbeitsgemeinschaft Kardiovaskulaere Nuklearmedizin der Deutschen Gesellschaft fuer Nuklearmedizin (Germany); Bengel, F.M. [Cardiovascular Nuclear Medicine, Johns Hopkins Medical Institutions, Baltimore (United States); Arbeitsgruppe Nuklearkardiologische Diagnostik der Deutschen Gesellschaft fuer Kardiologie (Germany); Zimmermann, R. [Arbeitsgruppe Nuklearkardiologische Diagnostik der Deutschen Gesellschaft fuer Kardiologie (Germany); Medizinische Klinik, Klinikum Pforzheim GmbH, Pforzheim (Germany); Dahl, J. vom [Klinik fuer Kardiologie, Kliniken Maria Hilf GmbH, Moenchengladbach (Germany); Schaefer, W. [Klinik fuer Nuklearmedizin, Universitaetsklinikum Aachen (Germany); Schober, O. [Klinik und Poliklinik fuer Nuklearmedizin, Universitaetsklinikum Muenster UKM (Germany); Schaefers, M. [Arbeitsgemeinschaft Kardiovaskulaere Nuklearmedizin der Deutschen Gesellschaft fuer Nuklearmedizin (Germany); Klinik und Poliklinik fuer Nuklearmedizin, Universitaetsklinikum Muenster UKM (Germany)

2009-07-01

Aim: This third survey of the working group Cardiovascular Nuclear Medicine of the German Society of Nuclear Medicine in cooperation with the working group Nuclear Cardiology of the German Cardiac Society was to deliver information on the procedures and in particular on the development of myocardial perfusion scintigraphy (MPS) from 2005 to 2007. Method: 370 questionnaires (222 private practices (PP), 117 hospitals (HO), 31 university hospitals (UH)) were evaluated. Results: MPS of 114,374 patients were reported, 83% were investigated with {sup 99m}Tc-perfusion tracers. 76% [2006=74%] were performed in PP, 15% [2006=17%] in HO and 9% [2006=9%] in UH. Diabetics represented 21% of all MPS patients in 2007. Data of 215 institutions which participated all from 2005 to 2007 showed an increase in MPS of 2.3% (PP +6.8%, HO -4.5%, UH -18.2%). The type of stress was pharmacological in 27% [2006 = 27%]; 67% adenosine (of these 25% with exercise), 31% dipyridamole (of these 55% with exercise), and 2% dobutamine. Gated SPECT was performed in 47% [2006 = 42%] of all rest and in 44% [2006 = 39%] of all stress MPS. 61% [2006 = 83%] of all institutions did not apply perfusion scores. 20% [2006 = 24%] of the institutions reported changes in the use of MPS by competing methods. Conclusion: There is a small increase of MPS between 2005 and 2007 despite competing methods. Gated SPECT has experienced more acceptance, but is still underrepresented. As compared to the European average and general standards of MPS a considerable backlog accounts to pharmacological stress tests, gated SPECT and perfusion scores. (orig.)

Baseline characteristics of the 3096 patients recruited into the 'Triple Antiplatelets for Reducing Dependency after Ischemic Stroke' trial.

Science.gov (United States)

Bath, Philip Mw; Appleton, Jason P; Beridze, Maia; Christensen, Hanne; Dineen, Robert A; Duley, Lelia; England, Timothy J; Heptinstall, Stan; James, Marilyn; Krishnan, Kailash; Markus, Hugh S; Pocock, Stuart; Ranta, Annemarei; Robinson, Thompson G; Flaherty, Katie; Scutt, Polly; Venables, Graham S; Woodhouse, Lisa J; Sprigg, Nikola

2017-07-01

Background The risk of recurrence following ischemic stroke or transient ischemic attack is highest immediately after the event. Antiplatelet agents are effective in reducing the risk of recurrence and two agents are superior to one in the early phase after ictus. Design The triple antiplatelets for reducing dependency after ischemic stroke trial was an international multicenter prospective randomized open-label blinded-endpoint trial that assessed the safety and efficacy of short-term intensive antiplatelet therapy with three agents (combined aspirin, clopidogrel and dipyridamole) as compared with guideline treatment in acute ischemic stroke or transient ischemic attack. The primary outcome was stroke recurrence and its severity, measured using the modified Rankin Scale at 90 days. Secondary outcomes included recurrent vascular events, functional measures (cognition, disability, mood, quality of life), and safety (bleeding, death, serious adverse events). Data are number (%) or mean (standard deviation, SD). Results Recruitment ran from April 2009 to March 2016; 3096 patients were recruited from 106 sites in four countries (Denmark 1.6%, Georgia 2.7%, New Zealand 0.2%, UK 95.4%). Randomization characteristics included: age 69.0 (10.1) years; male 1945 (62.8%); time onset to randomization 29.4 (11.9) h; stroke severity (National Institutes for Health Stroke Scale) 2.8 (3.6); blood pressure 143.5 (18.2)/79.5 (11.4) mmHg; IS 2143 (69.2%), transient ischemic attack 953 (30.8%). Conclusion Triple antiplatelets for reducing dependency after ischemic stroke was a large trial of intensive/triple antiplatelet therapy in acute ischemic stroke and transient ischemic attack, and included participants from four predominantly Caucasian countries who were representative of patients in many western stroke services.

Scintigraphy with Tc99m-MIBI to annual prediction the evolution of women referred for evaluation of precordial pain

International Nuclear Information System (INIS)

Peix, Amalia; Chacon, Deylis; Ponce, Felizardo; Lopez, Adlin; Cabrera, Omar; Maltas, Ana Ma.; Carrillo, Regla

2002-01-01

In order to evaluate the capacity of myocardial perfusion scintigraphy with Tc99m-MIBI to predict the evolution of women referred for evaluation of precordial pain, the rates of cardiovascular events at one year were studied in a group of patients with normal scintigraphy (group 1: 17 patients) and in another with reversible perfusion defects (group 2: 17 patients). The one-day protocol was applied for scintigraphy with Tc99m-MIBI (rest/stress) with combined stress (ergometrin bicycle plus 0.28 mg/Ig of dipyridamole) in those cases where it was necessary. A quantitative and qualitative analysis of the regional uptake was made. Patients from group 1 were younger than those from group 2 (average age: 49 vs 55, respectively, p = 0.04) and they had less hypercholesterolemia (112 % vs 59 %, respectively, p = 0.01). The rates of appearance of cardiovascular events at one year were calculated for patients from group 2 by using the Kaplan-Meier's method. The rates of appearance of clinical events (myocardial infarction and unstable angina) and of revascularization procedures (percutaneous transluminal coronary angioplasty and aortocoronary bypass surgery) were 0.24 in both cases. Only a patient from group 1 presented varying angina at 5 months. No deaths were reported in any of the groups. 94 % of the patients with normal perfusion scintigraphy were free of events after a one-year follow-up, whereas only 53 % of those with reversible perfusion defects showed a similar behavior. It was concluded that myocardial perfusion scintigraphy with Tc99m-MIBI is a useful tool to predict the evolution of women referred for evaluation of precordial pain at one year

Single-photon emission computed tomography for the assessment of ventricular perfusion and function

International Nuclear Information System (INIS)

Gonzalez, Patricio; Dussaillant, Gaston; Gutierrez, Daniela; Berrocal, Isabel; Alay, Rita; Otarola, Sonia

2013-01-01

Background: Single-photon emission computed tomography (SPECT) can be used as a non-invasive tool for the assessment of coronary perfusion. Aim: To assess ventricular perfusion and function by SPECT in patients with single vessel coronary artery disease. Material and Methods: Among patients with indications for a coronary artery angiography, those with significant lesions in one vessel, were selected for the study. Within 24 hours, cardiac SPECT examinations on basal conditions and after high doses of dipyridamole, were performed. SPECT data from 38 patients with a low probability of coronary artery disease was used for comparisons. Results:Ten patients aged 61 ± 8 years (seven men) were studied. Visual analysis of SPECT revealed signs suggestive of ischemia in eight patients. The remaining two patients did not have perfusion disturbances. SPECT detected eight of ten abnormal vessels reported in the coronary artery angiography. There were two false negative results Summed stress, summed rest and summed difference scores were 9.78 ± 6.51, 3.22 ± 5.07 and 6.33 ± 4.97, respectively. The ejection fractions under stress and at rest were 53 ± 11.7% and 61 ± 15.7% respectively (p ≤ 0.01). The figures for the control group were 69.1 ± 13.5% and 75.2 ± 12.04% respectively (significantly different from patients). Two patients had a summed motion score above 14.9. Likewise, two patients had a summed thickening score above 10.9. Conclusions: SPECT detected 80% of coronary lesions found during coronary artery angiography. Visual analysis of perfusion is highly reliable for diagnosis. Quantitative parameters must be considered only as reference parameters

Myocardial perfusion scintigraphy 2007 in Germany. Results of the query and current status

International Nuclear Information System (INIS)

Lindner, O.; Burchert, W.; Bengel, F.M.; Zimmermann, R.; Dahl, J. vom; Schaefer, W.; Schober, O.; Schaefers, M.

2009-01-01

Aim: This third survey of the working group Cardiovascular Nuclear Medicine of the German Society of Nuclear Medicine in cooperation with the working group Nuclear Cardiology of the German Cardiac Society was to deliver information on the procedures and in particular on the development of myocardial perfusion scintigraphy (MPS) from 2005 to 2007. Method: 370 questionnaires (222 private practices (PP), 117 hospitals (HO), 31 university hospitals (UH)) were evaluated. Results: MPS of 114,374 patients were reported, 83% were investigated with 99m Tc-perfusion tracers. 76% [2006=74%] were performed in PP, 15% [2006=17%] in HO and 9% [2006=9%] in UH. Diabetics represented 21% of all MPS patients in 2007. Data of 215 institutions which participated all from 2005 to 2007 showed an increase in MPS of 2.3% (PP +6.8%, HO -4.5%, UH -18.2%). The type of stress was pharmacological in 27% [2006 = 27%]; 67% adenosine (of these 25% with exercise), 31% dipyridamole (of these 55% with exercise), and 2% dobutamine. Gated SPECT was performed in 47% [2006 = 42%] of all rest and in 44% [2006 = 39%] of all stress MPS. 61% [2006 = 83%] of all institutions did not apply perfusion scores. 20% [2006 = 24%] of the institutions reported changes in the use of MPS by competing methods. Conclusion: There is a small increase of MPS between 2005 and 2007 despite competing methods. Gated SPECT has experienced more acceptance, but is still underrepresented. As compared to the European average and general standards of MPS a considerable backlog accounts to pharmacological stress tests, gated SPECT and perfusion scores. (orig.)

Stress perfusion magnetic resonance imaging to detect coronary artery lesions in children.

Science.gov (United States)

Vijarnsorn, Chodchanok; Noga, Michelle; Schantz, Daryl; Pepelassis, Dion; Tham, Edythe B

2017-05-01

Stress perfusion cardiovascular magnetic resonance (CMR) is used widely in adult ischemic heart disease, but data in children is limited. We sought to evaluate feasibility, accuracy and prognostic value of stress CMR in children with suspected coronary artery disease (CAD). Stress CMR was reviewed from two pediatric centers over 5 years using a standard pharmacologic protocol. Wall motion abnormalities, perfusion deficits and late enhancement were correlated with coronary angiogram (CAG) when available, and clinical status at 1 year follow-up for major adverse cardiovascular events (MACE; coronary revascularization, non-fatal myocardial infarction and death due to CAD) was recorded. Sixty-four stress perfusion CMR studies in 48 children (10.9 ± 4.8 years) using adenosine; 59 (92%) and dipyridamole; 5 (8%), were reviewed. Indications were Kawasaki disease (39%), post arterial switch operation (12.5%), post heart transplantation (12.5%), post anomalous coronary artery repair (11%), chest pain (11%), suspected myocarditis or CAD (3%), post coronary revascularization (3%), and others (8%). Twenty-six studies were performed under sedation. Of all studies performed, 66% showed no evidence of ischemia or infarction, 28% had perfusion deficits and 6% had late gadolinium enhancement (LGE) without perfusion deficit. Compared to CAG, the positive predictive value (PPV) of stress CMR was 80% with negative predictive value (NPV) of 88%. At 1 year clinical follow-up, the PPV and NPV of stress CMR to predict MACE were 78 and 98%. Stress-perfusion CMR, in combination with LGE and wall motion-analysis is a feasible and an accurate method of diagnosing CAD in children. In difficult cases, it also helps guide clinical intervention by complementing conventional CAG with functional information.

Value of myocardial perfusion SPECT in pediatric population

International Nuclear Information System (INIS)

Massardo, T.; Coll, C.; Prat, H.; Gonzalez, P.; Doggenweiller, P.; Castillo, M.E.; Solis, A.

2002-01-01

Isotopic myocardial perfusion studies are less frequently used in children than in adults and their indications are also different. Our goal was to analyze retrospectively the experience with stress perfusion myocardial SPECT in pediatric population. Method: Since 1998 to 2001, ten studies were performed to 5 girls and 3 boys. Their mean age was 7±3 years ranging from 1-11. Three of them presented abnormal coronary arteries pre and post surgical intervention with or without coil; three had Kawasaki disease with coronary aneurysms and the other two, congenital cardiopathies (Cantrell pentalogy and great vessel transposition,both with posterior left ventricular hypokinesia post surgery). Stress was obtained using dipyridamole infusion (0.56 mg/kg) in 6 cases and treadmill exercise using Bruce protocol in 4. All those tests were well tolerated. Sestamibi Tc99m was selected in 80% of the cases and Tl 201 in the rest. Only 2 small children required anesthesia during SPECT acquisition. Results: Stress EKG did not demonstrated ischemia in any case. Coronary angiography was performed only in 50% of the patients, it was concordant with SPECT features in all, two of those patients presented transient perfusion defects (one Kawasaki and one abnormal coronary artery with a fistulae).The repaired pentalogy presented ischemia and septal infarction; in that patient echocardiographic hipokinesia was concordant with fixed hypoperfusion. One case with abnormal coronary plus mitral regurgitation (without isotopic ischemia) was submitted to embolization posteriorly, obtaining motion improvement. Clinical outcome was concordant with the presence or absence of isotopic ischemia in the rest of the patients. Conclusion: SPECT myocardial perfusion was helpful in the therapeutic approach and in prediction of outcome in children

Noninvasive quantification of regional myocardial perfusion with rubidium-82 and positron emission tomography. Exploration of a mathematical model

International Nuclear Information System (INIS)

Herrero, P.; Markham, J.; Shelton, M.E.; Weinheimer, C.J.; Bergmann, S.R.

1990-01-01

Positron emission tomography (PET) centers without cyclotrons use generator-produced rubidium-82 (82Rb) for assessment of myocardial perfusion. The aim of the present study was to determine whether myocardial blood flow could be assessed quantitatively with 82Rb and PET. Because the myocardial extraction fraction of 82Rb varies inversely and nonlinearly with flow and cannot be measured conveniently with PET, we used an experimentally derived mathematical function defining the relation between single-pass extraction fraction of 82Rb and flow to obviate the necessity of measuring the extraction fraction directly. Myocardial blood flow in absolute terms (ml/g/min) was estimated from dynamic PET scans after intravenous administration of 82Rb in intact dogs and compared with flows measured with radiolabeled microspheres. In 36 comparisons in 13 dogs studied at rest, or after coronary occlusion, reperfusion, or after coronary hyperemia induced with intravenous dipyridamole, over the flow range from 0.2 to 2.0 ml/g/min, estimates of perfusion with rubidium correlated well with flows measured concomitantly with microspheres, although there was a slight underestimation of flow with rubidium (flow by 82Rb = 0.92 x flow by microspheres-0.021, r = 0.83). In general, estimates of flow in ischemic regions were less reliable than estimates for regions with normal flow. Thus, although the relation between myocardial extraction and retention of 82Rb and flow can vary under a variety of physiological and pathophysiological conditions, this study demonstrates the ability to obtain quantitative estimates of myocardial blood flow with 82Rb and PET under carefully defined conditions without measuring the extraction fraction directly

Oxidative stress/reactive metabolite gene expression signature in rat liver detects idiosyncratic hepatotoxicants

Energy Technology Data Exchange (ETDEWEB)

Leone, Angelique; Nie, Alex; Brandon Parker, J.; Sawant, Sharmilee; Piechta, Leigh-Anne; Kelley, Michael F., E-mail: mkelley2@its.jnj.com; Mark Kao, L.; Jim Proctor, S.; Verheyen, Geert; Johnson, Mark D.; Lord, Peter G.; McMillian, Michael K.

2014-03-15

Previously we reported a gene expression signature in rat liver for detecting a specific type of oxidative stress (OS) related to reactive metabolites (RM). High doses of the drugs disulfiram, ethinyl estradiol and nimesulide were used with another dozen paradigm OS/RM compounds, and three other drugs flutamide, phenacetin and sulindac were identified by this signature. In a second study, antiepileptic drugs were compared for covalent binding and their effects on OS/RM; felbamate, carbamazepine, and phenobarbital produced robust OS/RM gene expression. In the present study, liver RNA samples from drug-treated rats from more recent experiments were examined for statistical fit to the OS/RM signature. Of all 97 drugs examined, in addition to the nine drugs noted above, 19 more were identified as OS/RM-producing compounds—chlorpromazine, clozapine, cyproterone acetate, dantrolene, dipyridamole, glibenclamide, isoniazid, ketoconazole, methapyrilene, naltrexone, nifedipine, sulfamethoxazole, tamoxifen, coumarin, ritonavir, amitriptyline, valproic acid, enalapril, and chloramphenicol. Importantly, all of the OS/RM drugs listed above have been linked to idiosyncratic hepatotoxicity, excepting chloramphenicol, which does not have a package label for hepatotoxicity, but does have a black box warning for idiosyncratic bone marrow suppression. Most of these drugs are not acutely toxic in the rat. The OS/RM signature should be useful to avoid idiosyncratic hepatotoxicity of drug candidates. - Highlights: • 28 of 97 drugs gave a positive OS/RM gene expression signature in rat liver. • The specificity of the signature for human idiosyncratic hepatotoxicants was 98%. • The sensitivity of the signature for human idiosyncratic hepatotoxicants was 75%. • The signature can help eliminate hepatotoxicants from drug development.

Pharmacological Activity and Clinical Use of PDRN

Directory of Open Access Journals (Sweden)

Francesco Squadrito

2017-04-01

Full Text Available PDRN is a proprietary and registered drug that possesses several activities: tissue repairing, anti-ischemic, and anti-inflammatory. These therapeutic properties suggest its use in regenerative medicine and in diabetic foot ulcers. PDRN holds a mixture of deoxyribonucleotides with molecular weights ranging between 50 and 1,500 KDa, it is derived from a controlled purification and sterilization process of Oncorhynchus mykiss (Salmon Trout or Oncorhynchus keta (Chum Salmon sperm DNA. The procedure guarantees the absence of active protein and peptides that may cause immune reactions. In vitro and in vivo experiments have suggested that PDRN most relevant mechanism of action is the engagement of adenosine A2A receptors. Besides engaging the A2A receptor, PDRN offers nucleosides and nucleotides for the so called “salvage pathway.” The binding to adenosine A2A receptors is a unique property of PDRN and seems to be linked to DNA origin, molecular weight and manufacturing process. In this context, PDRN represents a new advancement in the pharmacotherapy. In fact adenosine and dipyridamole are non-selective activators of adenosine receptors and they may cause unwanted side effects; while regadenoson, the only other A2A receptor agonist available, has been approved by the FDA as a pharmacological stress agent in myocardial perfusion imaging. Finally, defibrotide, another drug composed by a mixture of oligonucleotides, has different molecular weight, a DNA of different origin and does not share the same wound healing stimulating effects of PDRN. The present review analyses the more relevant experimental and clinical evidences carried out to characterize PDRN therapeutic effects.

Stress cine MRI for detection of coronary artery disease

International Nuclear Information System (INIS)

Sommer, T.; Hofer, U.; Schild, H.

2002-01-01

Stress testing is the cornerstone in the diagnosis of patients with suspected coronary artery disease (CAD). Stress echocardiography has become a well-established modality for the detection of ischemia-induced wall motion abnormalities. However, display and reliable interpretation of stress echocardiography studies are user-dependent, the test reproducibility is low, and 10 to 15% of patients yield suboptimal or non-diagnostic images. Due to its high spatial and contrast resolution, MRI is known to permit an accurate determination of left ventricular function and wall thickness at rest. Early stress MRI studies provided promising results with respect to the detection of CAD. However, the clinical impact was limited due to long imaging time and problematic patient monitoring in the MRI environment. Recent technical improvements - namely ultrafast MR image acquisition - led to a significant reduction of imaging time and improved patient safety. Stress can be induced by physical exercise or pharmacologically by administration of a beta 1 -agonist (dobutamine) or vasodilatator (dipyridamole and adenosine). The best developed and most promising stress MRI technique is a high-dose dobutamine/atropine stress protocol (10, 20, 30, 40 μg/kg/min; optionally 0.25-mg fractions of atropine up to maximal dose 1 mg). Severe complications (myocardial infarction, ventricular fibrillation and sustained tachycardia, cardiogenic shock) may be expected in 0.25% of patients. Currently, data of three high-dose dobutamine stress MRI studies are available, revealing a good sensitivity (83 - 87%) and specificity (83 - 86%) in the assessment of CAD. The direct comparison between echocardiography and MRI for the detection of stress-induced wall motion abnormalities yielded better results for dobutamine-MRI in terms of sensitivity (86.2% vs. 74.3%; p [de

Stress-induced myocardial ischemia is associated with early post-stress left ventricular mechanical dyssynchrony as assessed by phase analysis of {sup 201}Tl gated SPECT myocardial perfusion imaging

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Chen, Chien-Cheng; Shen, Thau-Yun [Show Chwan Memorial Hospital, Department of Cardiology, Changhua (China); Chang, Ming-Che [Changhua Christian Hospital, Department of Nuclear Medicine, Changhua (China); Hung, Guang-Uei [Chang Bing Show Chwan Memorial Hospital, Department of Nuclear Medicine, Changhua (China); China Medical University, Department of Biomedical Imaging and Radiological Science, Taichung (China); Chen, Wan-Chen [Chang Bing Show Chwan Memorial Hospital, Department of Nuclear Medicine, Changhua (China); Kao, Chia-Hung [China Medical University, Department of Biomedical Imaging and Radiological Science, Taichung (China); Chen, Ji [Emory University School of Medicine, Department of Radiology and Imaging Sciences, Atlanta, GA (United States)

2012-12-15

In {sup 201}Tl SPECT myocardial perfusion imaging (MPI) data are acquired shortly after the stress injection to assess early post-stress left ventricle (LV) function. The purpose of this study was to use {sup 201}Tl SPECT MPI to investigate whether stress-induced myocardial ischemia is associated with LV mechanical dyssynchrony. Enrolled in the study were 75 patients who were referred for dipyridamole stress and rest {sup 201}Tl gated SPECT MPI. The early post-stress scan was started 5 min after injection, and followed by the rest scan 4 h later. The patients were divided into three groups: ischemia group (N = 25, summed stress score, SSS, {>=}5, summed rest score, SRS, <5), infarct group (N = 16, SSS {>=}5, SRS {>=}5) and normal group (N = 34, SSS <5, SRS <5). LV dyssynchrony parameters were calculated by phase analysis, and compared between the stress and rest images. In the ischemia group, LV dyssynchrony was significantly larger during stress than during rest. On the contrary, LV dyssynchrony during stress was significantly smaller than during rest in the normal and infarct groups. LV dyssynchrony during rest was significantly larger in the infarct group than in the normal and ischemia groups. There were no significant differences in LV dyssynchrony during rest between the normal and ischemia groups. Stress-induced myocardial ischemia caused dyssynchronous contraction in the ischemic region, leading to a deterioration in LV synchrony. Normal myocardium had more synchronous contraction during stress. The different dyssynchrony pattern between ischemic and normal myocardium early post-stress may aid the diagnosis of coronary artery disease using {sup 201}Tl gated SPECT MPI. (orig.)

Postoperative Functional Outcome After Off-Pump Versus On-Pump Coronary Artery Bypass Grafting Using Gated Myocardial SPECT: A Comparison by Propensity Score Analysis

International Nuclear Information System (INIS)

Lee, Jong Jin; Paeng, Jin Chul; Lee, Dong Soo; Kim, Ki Bong; Chung, June Key; Lee, Myung Chul; Kang, Won Jun

2010-01-01

We evaluated the short-term and mid-term differences in perfusion and function after off-pump and on-pump coronary artery bypass grafting (CABG) using gated myocardial single photon emission computed tomography. A total of 70 patients with coronary artery disease who underwent CABG were included based on the propensity score matching results from 165 patients. Thirty-five patients underwent off-pump and 35 patients on-pump CABG. Rest 201 TI/dipyridamole stress 99m Tc-methoxyisobutylisonitrile gated single photon emission computed thermographs were performed preoperatively and postoperatively at short-term (103±23 days after surgery) and mid-term follow-up (502±111 days after surgery). Changes in left ventricular ejection fraction, end systolic volume, stress and rest segmental perfusion, and segmental wall thickening were compared between the two groups. The segments with preoperative rest 201 T1 uptake under 60% of maximum uptake were included in the segmental analysis. Left ventricular ejection fraction (P=0.001) and end systolic volume (P=0.008) showed significant improvement in both groups. There were no significant short-term and mid-term differences between the two groups in terms of left ventricular ejection fraction (P=0.309) and end systolic volume (P=0.938). Likewise, segmental rest (P=0.178) and stress perfusion (P=0.071), and systolic wall thickening (P=0.241) showed significant improvement in both groups with similar time courses. Off-pump CABG resulted in significant improvements in left ventricular ejection fraction, end systolic volume, and regional myocardial perfusion and function that are comparable to on-pump CABG at short-term and mid-term. Gated myocardial SPECT successfully revealed that off-pump CABG is as good as on-pump CABG from the viewpoint of myocardial perfusion and function.

Role of quantitative myocardial positron emission tomography for risk stratification in patients with hypertrophic cardiomyopathy: a 2016 reappraisal

Energy Technology Data Exchange (ETDEWEB)

Castagnoli, Helga; Passeri, Alessandro; Berti, Valentina; Sciagra, Roberto [University of Florence, Department of Experimental and Clinical Biomedical Sciences - Nuclear Medicine Unit, Firenze (Italy); Ferrantini, Cecilia; Coppini, Raffaele; Baldini, Katia; Cecchi, Franco; Olivotto, Iacopo [Careggi University Hospital, Referral Center for Myocardial Diseases and Genetic Diagnostics Unit, Florence (Italy)

2016-12-15

Myocardial blood flow <1.1 mL/min/g following dipyridamole (Dip-MBF) assessed by positron emission tomography (PET) was identified in 2003 as an important outcome predictor in hypertrophic cardiomyopathy (HCM), based on scans performed in the 90s. However, such extreme Dip-MBF impairment is rarely observed in contemporary cohorts. We, therefore, reassessed the Dip-MBF threshold defining high-risk HCM patients. Dip-MBF was measured using {sup 13}N-ammonia in 100 HCM consecutive patients, prospectively enrolled and followed for 4.0 ± 2.2 years. Outcome was assessed based on tertiles of Dip-MBF. The study end-point was a combination of cardiovascular death, progression to severe functional limitation, cardioembolic stroke, life-threatening ventricular arrhythmias. Global Dip-MBF was 1.95 ± 0.85, ranging from 0.7 to 5.9 mL/min/g. Dip-MBF tertile cut-off values were: 0.73 to 1.53 mL/min/g (lowest), 1.54 to 2.13 mL/min/g (middle), and 2.14 to 5.89 mL/min/g (highest). During follow-up, lowest tertile Dip-MBF was associated with sevenfold independent risk of unfavorable outcome compared to the other two tertiles. Dip-MBF 1.35 mL/min/g was identified as the best threshold for outcome prediction. Regional perfusion analysis showed that all cardiac deaths (n = 4) occurred in patients in the lowest tertile of lateral wall Dip-MBF (≤1.72 mL/min/g); septal Dip-MBF was not predictive. Dip-MBF confirms its role as potent predictor of outcome in HCM. However, the threshold for prediction in a contemporary cohort is higher than that reported in earlier studies. Dip-MBF impairment in the lateral wall, possibly reflecting diffuse disease extending to non-hypertrophic regions, is a sensitive predictor of mortality in HCM. (orig.)

On demand manufacturing of patient-specific liquid capsules via co-ordinated 3D printing and liquid dispensing.

Science.gov (United States)

Okwuosa, Tochukwu C; Soares, Cindy; Gollwitzer, Verena; Habashy, Rober; Timmins, Peter; Alhnan, Mohamed A

2018-06-15

A method for the production of liquid capsules with the potential of modifying drug dose and release is presented. For the first time, the co-ordinated use of fused deposition modelling (FDM), 3D printing and liquid dispensing to fabricate individualised dosage form on demand in a fully automated fashion has been demonstrated. Polymethacrylate shells (Eudragit EPO and RL) for immediate and extended release were fabricated using FDM 3D printing and simultaneously filled using a computer-controlled liquid dispenser loaded with model drug solution (theophylline) or suspension (dipyridamole). The impact of printing modes: simultaneous shell printing and filling (single-phase) or sequential 3D printing of shell bottom, filling and shell cap (multi-phase), nozzle size, syringe volume, and shell structure has been reported. The use of shell thickness of 1.6 mm, and concentric architecture allowed successful containment of liquid core whilst maintaining the release properties of the 3D printed liquid capsule. The linear relationship between the theoretical and the actual volumes from the dispenser reflected its potential for accurate dosing (R 2  = 0.9985). Modifying the shell thickness of Eudragit RL capsule allowed a controlled extended drug release without the need for formulation change. Owing to its low cost and versatility, this approach can be adapted to wide spectrum of liquid formulations such as small and large molecule solutions and obviate the need for compatibility with the high temperature of FDM 3D printing process. In a clinical setting, health care staff will be able to instantly manufacture in small volumes liquid capsules with individualised dose contents and release pattern in response to specific patient's needs. Copyright © 2018 Elsevier B.V. All rights reserved.

Influence of the prevalence of coronary artery disease in patients with normal myocardial perfusion SPECT imaging. Cooperative study in South America

International Nuclear Information System (INIS)

Balestrini, V.R.; Arja, V.J.; Sandrin, A.L.; Sala, J.P.; Joekes, S.; Bier, G.; Precoma, D.; Yamada, A.

2002-01-01

An important feature of myocardial perfusion imaging is the ability to predict prognosis and identify high- and low-risk patients for coronary events. According to Bayes' theorem, the significance of test's results, relates not only the sensitivity and specificity of a test but also the prevalence of disease in the population under study. Aim: evaluate the relationship between pretest likelihood (PTL) and coronary events (CE) in patients with normal myocardial perfusion SPECT imaging during a long period of time. Material and Methods: The population included 709 patients (411 men and 298 women, mean age 58 years old) who underwent stress/rest myocardial perfusion SPECT imaging at nuclear cardiology laboratories in Argentina and Brazil, with scintigraphic images interpreted as normal. Analyzed variables: clinical, EKG and stress test. Perfusion agents: Tc-99m-tetrofosmin: 36.5%, Tc99m-sestamibi 5.8% and Tl-201 57.7%. Mean follow up: 919 days. CE: soft (unstable angina and need for revascularization) and hard (AMI and cardiac death). Results: Stress test: exercise stress test 72.2%, dipyridamole 25%, adenosine 1.7%, dobutamine 1.1%. PTL [ 9' (M/F): 59/11% (p 78%] 31 vs. 50%. Conclusions: 1) There was a relationship between PTL, events rate and time to event. 2) We found a low hard events rate (0.85%). 3) The results in this group of patients with normal myocardial perfusion SPECT imaging may suggest a guarantee period of low risk of coronary events between 2-3 years. 4) In spite of there is a low event rate in total population with normal myocardial perfusion imaging, patients with highest prevalence of coronary artery disease have more statistical probabilities of coronary events and therefore they have to be watched closely

Coupling of UDP-glucuronosyltransferases and multidrug resistance-associated proteins is responsible for the intestinal disposition and poor bioavailability of emodin

International Nuclear Information System (INIS)

Liu, Wei; Feng, Qian; Li, Ye; Ye, Ling; Hu, Ming; Liu, Zhongqiu

2012-01-01

Emodin is a poorly bioavailable but promising plant-derived anticancer drug candidate. The low oral bioavailability of emodin is due to its extensive glucuronidation in the intestine and liver. Caco-2 cell culture model was used to investigate the interplay between UDP-glucuronosyltransferases (UGTs) and efflux transporters in the intestinal disposition of emodin. Bidirectional transport assays of emodin at different concentrations were performed in the Caco-2 monolayers with or without multidrug resistance-associated protein (MRP) and breast cancer resistance protein (BCRP) efflux transporter chemical inhibitors. The bidirectional permeability of emodin and its glucuronide in the Caco-2 monolayers was determined. Emodin was rapidly metabolized to emodin glucuronide in Caco-2 cells. LTC4, a potent inhibitor of MRP2, decreased the efflux of emodin glucuronide and also substantially increased the intracellular glucuronide level in the basolateral-to-apical (B–A) direction. MK-571, chemical inhibitor of MRP2, MRP3, and MRP4, significantly reduced the efflux of glucuronide in the apical-to-basolateral (A–B) and B–A directions in a dose-dependent manner. However, dipyridamole, a BCRP chemical inhibitor demonstrated no effect on formation and efflux of emodin glucuronide in Caco-2 cells. In conclusion, UGT is a main metabolic pathway for emodin in the intestine, and the MRP family is composed of major efflux transporters responsible for the excretion of emodin glucuronide in the intestine. The coupling of UGTs and MRP efflux transporters causes the extensive metabolism, excretion, and low bioavailability of emodin. -- Highlights: ► Glucuronidation is the main reason for the poor oral bioavailability of emodin. ► Efflux transporters are involved in the excretion of emodin glucuronide. ► The intestine is the main organ for metabolism of emodin.

Gated-SPECT myocardial scintigraphy in left bundle branch block: A study in patients with and without coronary artery disease

International Nuclear Information System (INIS)

Falcao, A.M.; Moffa, P.J.; Chalela, W.A.; Soares, J.; Oliveira, C.G.; Kreling, J.C.; Ferreira, B.A.; Uchida, A.H.; Meneghetti, J.C.

2002-01-01

Introduction: Myocardial perfusion scintigraphy (MPS) is a non-invasive method helpful for evaluating coronary heart disease. In left bundle branch block (LBBB), the myocardial scintigraphy frequently reveals septal abnormalities in the absence of coronary artery disease (CAD) and gives rise to 'false-positive' results in patients (pts) with suspected CAD. The purpose of this study was to assess the diagnostic role of ECG-gated SPECT in pts with complete LBBB, with and without known CAD. Methods. This study included 46 pts, 29 women (63%), with mean age 63.8 ± 11.6yr, divided into two groups: Group 1 (n=21 pts) with LBBB and CAD angiographically confirmed and Group 2 (n=25 pts) with LBBB and normal coronangiography. All pts underwent MPS at rest and two stress tests - dipyridamole (DIP) and treadmill exercise test (ET) with Bruce protocol. Myocardial perfusion, wall motility and wall thickening were analyzed qualitatively by consensus of two observers in anterior, septal, inferior, lateral and apical myocardial segments. Scores were attributed to: perfusion as normal, reversible or fixed defects; motility as normal, hypokinesia, akinesia or dyskinesia and thickening if present or absent. The left ventricle ejection fraction (LVEF) was automatically calculated from the ECG-gated SPECT. Results: The comparative analysis between groups 1 and 2 for both stresses (DIP and ET) for the parameters analyzed in the myocardial segments are presented: LVEF at rest, ET and DIP show statistically significant differences between groups 1 and 2 (p<0.0001). Conclusion: In the anterior and septal segments, only septal thickening was capable of differentiating between LBBB with and without CAD, independent of the kind of stress. In the other segments there was no influence of disturbance conduction for the perfusion analysis

Benefits and Risks of Antithrombotic Therapy in Essential Thrombocythemia: A Systematic Review.

Science.gov (United States)

Chu, Derek K; Hillis, Christopher M; Leong, Darryl P; Anand, Sonia S; Siegal, Deborah M

2017-08-01

Patients with essential thrombocythemia (ET) are at high risk for both thrombosis and hemorrhage. To evaluate the risks and benefits of antithrombotic therapy in adults with ET. Multiple databases, including MEDLINE, EMBASE, and the Cochrane Central Register of Controlled Trials, through 4 March 2017. Randomized and observational studies of antiplatelet or anticoagulant therapy, published in any language and reporting thrombotic or hemorrhagic events. Two reviewers independently extracted data, assessed risk of bias, and graded certainty of evidence. No relevant randomized trials were identified. Twenty-four observational studies (18 comparative and 6 single-group) involving 6153 patients followed for 31 711 patient-years were reviewed; most were deemed to have high risk of bias. Most patients receiving antiplatelet therapy (3613 of 4527 [80%]) received low-dose aspirin (50 to 150 mg/d); 914 (20%) received high-dose aspirin (300 to 600 mg/d), dipyridamole, or other agents. Overall, findings were inconsistent and imprecise. The reported incidence rates of thrombosis, any bleeding, and major bleeding without antiplatelet therapy ranged from 5 to 110 (median, 20), from 3 to 39 (median, 8), and from 2 to 53 (median, 6) cases per 1000 patient-years, respectively. The reported relative risks for thrombosis, any bleeding, and major bleeding with antiplatelet therapy compared with none ranged from 0.26 to 3.48 (median, 0.74), from 0.48 to 11.04 (median, 1.95), and from 0.48 to 5.17 (median, 1.30), respectively. Certainty of evidence was rated low or very low for all outcomes. No randomized trials, no extractable data on anticoagulants, lack of uniform bleeding definitions, and systematic reporting of outcomes. Available evidence about the risk-benefit ratio of antiplatelet therapy in adults with ET is highly uncertain. Regional Medical Associates. (PROSPERO: CRD42015027051).

Role of redistribution and 24 hour reinjection images to assess myocardial viability in patients with acute myocardial infarction

International Nuclear Information System (INIS)

Yoon, Seok Nam; Pai, Moon Sun; Park, Chan H.; Yoon, Myung Ho; Choi, Byung Il

1998-01-01

We evaluated the importance of redistribution and 24 hour reinjection images in Tl-201 SPECT assessment of myocardial viability after acute myocardial infarction (AMI). We performed dipyridamole stress-4 hour redistribution-24 hour reinjection Tl-201 SPECT in 43 patients with recent AMI (4-16 days). The myocardium was divided into 16 segments and perfusion grade was measured visually with 4 point score from 0 to 3 (absent uptake to normal uptake). A perfusion defect with stress score 2 was considered moderate. A defect was considered severe if the stress score was 0 or 1 (absent uptake or severe perfusion decrease). Moderate defect on stress image were considered viable and and segments with severe defect were considered viable if they showed improvement of 1 score or more on redistribution or reinjection images. We compared the results of viability assessment in stress-redistribution and stress-reinjection images. On visual analysis, 344 of 688 segments (50%) had abnormal perfusion. Fify two (15%) had moderate perfusion defects and 292 (85%) had severe perfusion defects on stress image. Of 292 severe stress defects, 53 were irreversible on redistribution and reversible on reinjection images, and 15 were reverseble on redistribution and irreversible on reinjection images. Two hundred twenty four of 292 segments (76.7%) showed concordant results on stress-redistribution and stress- reinjection images. Therefore 24 hour reinjection image changed viability status from necrotic to viable in 53 segments of 292 severe stress defect (18%). However, myocardial viability was underestimated in only 5% (15/292) of severe defects by 24 hour reinjection. The 24 hour reinjection imaging is useful in the assessment of myocardial viability. It is more sensitive than 4 hour redistribution imaging. However, both redistribution and reinjection images are needed since they complement each other

Role of quantitative myocardial positron emission tomography for risk stratification in patients with hypertrophic cardiomyopathy: a 2016 reappraisal

International Nuclear Information System (INIS)

Castagnoli, Helga; Passeri, Alessandro; Berti, Valentina; Sciagra, Roberto; Ferrantini, Cecilia; Coppini, Raffaele; Baldini, Katia; Cecchi, Franco; Olivotto, Iacopo

2016-01-01

Myocardial blood flow <1.1 mL/min/g following dipyridamole (Dip-MBF) assessed by positron emission tomography (PET) was identified in 2003 as an important outcome predictor in hypertrophic cardiomyopathy (HCM), based on scans performed in the 90s. However, such extreme Dip-MBF impairment is rarely observed in contemporary cohorts. We, therefore, reassessed the Dip-MBF threshold defining high-risk HCM patients. Dip-MBF was measured using "1"3N-ammonia in 100 HCM consecutive patients, prospectively enrolled and followed for 4.0 ± 2.2 years. Outcome was assessed based on tertiles of Dip-MBF. The study end-point was a combination of cardiovascular death, progression to severe functional limitation, cardioembolic stroke, life-threatening ventricular arrhythmias. Global Dip-MBF was 1.95 ± 0.85, ranging from 0.7 to 5.9 mL/min/g. Dip-MBF tertile cut-off values were: 0.73 to 1.53 mL/min/g (lowest), 1.54 to 2.13 mL/min/g (middle), and 2.14 to 5.89 mL/min/g (highest). During follow-up, lowest tertile Dip-MBF was associated with sevenfold independent risk of unfavorable outcome compared to the other two tertiles. Dip-MBF 1.35 mL/min/g was identified as the best threshold for outcome prediction. Regional perfusion analysis showed that all cardiac deaths (n = 4) occurred in patients in the lowest tertile of lateral wall Dip-MBF (≤1.72 mL/min/g); septal Dip-MBF was not predictive. Dip-MBF confirms its role as potent predictor of outcome in HCM. However, the threshold for prediction in a contemporary cohort is higher than that reported in earlier studies. Dip-MBF impairment in the lateral wall, possibly reflecting diffuse disease extending to non-hypertrophic regions, is a sensitive predictor of mortality in HCM. (orig.)

A quantitative index of regional blood flow in canine myocardium derived noninvasively with N-13 ammonia and dynamic positron emission tomography

Energy Technology Data Exchange (ETDEWEB)

Nienaber, C.A.; Ratib, O.; Gambhir, S.S.; Krivokapich, J.; Huang, S.C.; Phelps, M.E.; Schelbert, H.R. (Univ. of California, Los Angeles School of Medicine (USA))

1991-01-01

To derive a quantitative index of regional myocardial blood flow, the arterial input function of the flow tracer N-13 ammonia and the regional myocardial N-13 activity concentrations were noninvasively determined in 29 experiments in eight dogs. N-13 ammonia was administered intravenously and cross-sectional images were acquired dynamically using an ECAT III positron emission tomograph with an effective in-plane resolution of 13.46 mm full-width half-maximum. Time-activity curves were derived from the serial images by assigning regions of interest to the left ventricular myocardium and left ventricular blood pool. Tracer net extractions were estimated from the myocardial time-activity concentrations at various times after tracer injection and the integral of the arterial input function. Myocardial blood flow was altered by intravenous dipyridamole, morphine, propranolol and partial or complete occlusion of the left anterior descending coronary artery, and ranged from 9 to 860 ml/min per 100 g. Estimates of tracer net extractions were most accurate when determined from the myocardial N-13 activity concentrations at 60 s divided by the integral of the arterial input function to that time. These estimates correlated with regional myocardial blood flows determined independently by the microsphere technique by y = x (1 - 0.64(e-114/x); SEE = 22.9; r = 0.94). First pass extraction fractions of N-13 ammonia determined noninvasively with this approach declined with higher flows in a nonlinear fashion and were similar to those determined invasively by direct intracoronary N-13 ammonia injections. The findings indicate that an accurate index of regional myocardial blood flow can be obtained noninvasively by high temporal sampling of arterial and myocardial tracer activity concentrations with positron emission tomography.

Myocardial Perfusion SPECT 2015 in Germany

Science.gov (United States)

Burchert, Wolfgang; Schäfer, Wolfgang; Hacker, Marcus

2016-01-01

Summary Aim The working group Cardiovascular Nuclear Medicine of the German Society of Nuclear Medicine presents the results of the 7th survey of myocardial perfusion SPECT (MPS) of the reporting year 2015. Method 268 questionnaires (173 practices [PR], 67 hospitals [HO], 28 university hospitals [UH]) were evaluated. Results of the last survey from 2012 are set in squared brackets. Results MPS of 121 939 [105 941] patients were reported. 98 % [95 %] of all MPS were performed with Tc-99m radiopharmaceuticals and 2 % [5 %] with Tl-201. 78 % [79 %] of all patients were studied in PR, 14 % [15 %] in HO, and 8 % [6 %] in UH. A pharmacological stress test was performed in 43 % [39 %] (22 % [24 %] adenosine, 20 % [9 %] regadenoson, 1% [6 %] dipyridamole or dobutamine). Attenuation correction was applied in 25 % [2009: 10 %] of MPS. Gated SPECT was performed in 78 % [70 %] of all rest MPS, in 80 % [73 %] of all stress and in 76 % [67 %] of all stress and rest MPS. 53 % [33 %] of all nuclear medicine departments performed MPS scoring by default, whereas 24 % [41 %] did not apply any quantification. 31 % [26 %] of all departments noticed an increase in their counted MPS and 29 % [29 %] no changes. Data from 89 departments which participated in all surveys showed an increase in MPS count of 11.1 % (PR: 12.2 %, HO: 4.8 %, UH: 18.4 %). 70 % [60 %] of the MPS were requested by ambulatory care cardiologists. Conclusion The 2015 MPS survey reveals a high-grade adherence of routine MPS practice to current guidelines. The positive trend in MPS performance and number of MPS already observed in 2012 continues. Educational training remains necessary in the field of SPECT scoring. PMID:27909712

Noninvasive assessment of coronary stenoses by myocardial imaging during pharmacologic coronary vasodilation. VI. Detection of coronary artery disease in human beings with intravenous N-13 ammonia and positron computed tomography

International Nuclear Information System (INIS)

Schelbert, H.R.; Wisenberg, G.; Phelps, M.E.; Gould, K.L.; Henze, E.; Hoffman, E.J.; Gomes, A.; Kuhl, D.E.

1982-01-01

The possibility of detecting mild coronary stenoses with positron computed tomography and nitrogen (N-13) ammonia administered during pharmacologic coronary vasodilation was previously demonstrated in chronically instrumented dogs. The feasibility of using this technique in human beings and its sensitivity in determining the degree and extent of coronary artery disease were examined in 13 young normal healthy volunteers and 32 patients with angiographically documented coronary artery disease. N-13 ammonia was administered intravenously and its distribution in the left ventricular myocardium recorded at rest and during dipyridamole-induced coronary hyperemia. In the 13 volunteers, N-13 activity was homogeneous at rest and during hyperemia, whereas 31 of the 32 patients had regional defects on the hyperemic images not present during rest. All six patients with double, all 10 with triple and 15 of 16 patients with single vessel disease (97 percent) were correctly identified with the technique. Two vessel involvement was correctly identified in five of the six patients with double vessel disease and three vessel disease in six of 10 patients. Of all 58 coronary stenoses, 52 (90 percent) were correctly identified. In a subgroup of 11 patients, the technique was compared with exercise thallium-201 planar images, which were abnormal in 10 (91 percent) whereas N-13 images were abnormal in all 11. Of the 19 stenosed coronary arteries in this subgroup, 11 (58 percent) were correctly identified with thallium-201 and 17 (89 percent) with tomography (p less than 0.01). It is concluded that cross-sectional imaging of the myocardial distribution of N-13 ammonia administered during pharmacologic coronary vasodilation is a highly sensitive and accurate means for noninvasive detection of coronary stenoses in human beings and for estimating the extent of coronary artery disease

Diagnosis, management and prevention of ischemic stroke for non-neurologists

Directory of Open Access Journals (Sweden)

Kavian Ghandehari

2011-07-01

Full Text Available Background: Stroke is the third common cause of disability and death. Diagnosis of stroke is based on its clinical manifestations and/or observation of infarct in the neuroimaging. Standard battery of diagnostic investigations and classification criteria is required for detection of stroke etiology. Materials and Method: This review article deals with the diagnosis and management of brain infarction particularly in our country and is provided for non-neurologists. Using online scientific search engines and in some parts referring to laboratory archives constituted base of this review article.Results: Acute stroke management is almost similar in its various etiologies. Neuroprotective drugs have little value in acute stroke management. At present time, a few Iranian medical centers have infrastructure of thrombolysis therapy. Prevention of stroke is based on the detection and control of its risk factors. Aspirin, 80 mg per day is the most common drug for stroke prevention. Co-administration of aspirin 80 mg/d and Dipyridamole 200-400 mg/d increases the preventive effects of aspirin. Clopidogrel 75 mg/d is the stroke preventive drug of choice in patients with peptic ulcer and coronary artery disease. Co-administration of aspirin and clopidogrel is more effective in stroke prevention but has more hemorrhagic complications. Using warfarin for stroke prevention is suggested only in patients who have facilities for repetitive coagulation tests. Carotid endarterectomy is indicated in symptomatic patients with more than 70% stenosis of extracranial internal carotid artery, if performed only by vascular surgeons experienced in carotid surgery.Conclusion: Many stroke patients are managed by general practitioners and non-neurologists, e.g. internists, cardiologists and neurosurgeons. This review article provides continuous medical education according to Iranian medical curriculum

Clinical application of cardiac SPECT

International Nuclear Information System (INIS)

Nishimura, Shigeyuki

1999-01-01

Single-photon emission computed tomography (SPECT) has replaced planar imaging techniques for myocardial scintigraphy. Thallium-201 was the dominant agent employed for myocardial perfusion imaging. Today new technetium-99m labelled radionuclides have been used as excellent alternatives to 201 Tl for detection of coronary artery disease, prognostification, and even assessment of myocardial viability. Pharmacologic stress imaging using either dipyridamole, adenosine or dobutamine is a substitute for exercise stress. Accurate determination of myocardial viability is vitally important for clinical decision making for patients with LV dysfunction who will most benefit from revascularization. Stunned and hibernated myocardium may result in profound regional LTV dysfunction in absence of necrosis. The various approach such as stress-redistribution-reinjection imaging, rest-redistribution imaging and stress-redistribution-24 hours delayed imaging has been utilized to assess myocardial viability with 201 Tl. Quantitative assessment of 99m Tc MIBI uptake reflect the degree of viability. 123 I-Metaiodobenzylguanidine (MIBG), an analog of norepinephrine, has been used for scintigraphic assessment of regional cardiac adrenergic innervation. Cardiac sympathetic denervation, assessed by 123 I-MIBG, due to ischemia in non-Q myocardial infarction and unstable angina has been shown. Quantitative cardiac MIBG scintigram was shown to have prognostic value in patients with severe congestive heart failure. 23 I-BMIPP (ρ-methyl-iodophenyl pentadecanoic acid) has been used to assess myocardial fatty acid utilization. BMIPP has the memory function of ischemia in unstable angina, since decreased BMIPP uptake persists several days after ischemic episode. Nuclear cardiology in Japan has experienced an expansion in the techniques including use of new radionuclides, 99m Tc perfusion agents, 123 I-MIBG and 23 I-BMIPP and in associated clinical application to the various cardiac diseases

Quantification of Regional Myocardial Oxygenation by Magnetic Resonance Imaging: Validation with Positron Emission Tomography

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McCommis, Kyle S.; Goldstein, Thomas A.; Abendschein, Dana R.; Herrero, Pilar; Misselwitz, Bernd; Gropler, Robert J.; Zheng, Jie

2011-01-01

Background A comprehensive evaluation of myocardial ischemia requires measures of both oxygen supply and demand. Positron emission tomography (PET) is currently the gold standard for such evaluations, but its use is limited due to its ionizing radiation, limited availability, and high cost. A cardiac magnetic resonance imaging (MRI) method was developed for assessing myocardial oxygenation. The purpose of this study was to evaluate and validate this technique compared to PET during pharmacologic stress in a canine model of coronary artery stenosis. Methods and Results Twenty-one beagles and small mongrel dogs without coronary artery stenosis (controls), or with moderate to severe acute coronary artery stenosis underwent MRI and PET imaging at rest and during dipyridamole vasodilation or dobutamine stress to induce a wide range of changes in cardiac perfusion and oxygenation. MRI first-pass perfusion imaging was performed to quantify myocardial blood flow (MBF) and volume (MBV). The MRI blood-oxygen-level-dependent (BOLD) technique was used to determine the myocardial oxygen extraction fraction (OEF) during pharmacologic hyperemia. Myocardial oxygen consumption (MVO2) was determined by Fick’s law. In the same dogs, 15O-water and 11C-acetate were used to measure MBF and MVO2, respectively, by PET. Regional assessments were performed for both MR and PET. MRI data correlated nicely with PET values for MBF (R2 = 0.79, P < 0.001), MVO2 (R2 = 0.74, P < 0.001), and OEF (R2 = 0.66, P < 0.01). Conclusions Cardiac MRI methods may provide an alternative to radionuclide imaging in settings of myocardial ischemia. Our newly developed quantitative MRI oxygenation imaging technique may be a valuable non-invasive tool to directly evaluate myocardial energetics and efficiency. PMID:19933371

On the role of subtype selective adenosine receptor agonists during proliferation and osteogenic differentiation of human primary bone marrow stromal cells.

Science.gov (United States)

Costa, M Adelina; Barbosa, A; Neto, E; Sá-e-Sousa, A; Freitas, R; Neves, J M; Magalhães-Cardoso, T; Ferreirinha, F; Correia-de-Sá, P

2011-05-01

Purines are important modulators of bone cell biology. ATP is metabolized into adenosine by human primary osteoblast cells (HPOC); due to very low activity of adenosine deaminase, the nucleoside is the end product of the ecto-nucleotidase cascade. We, therefore, investigated the expression and function of adenosine receptor subtypes (A(1) , A(2A) , A(2B) , and A(3) ) during proliferation and osteogenic differentiation of HPOC. Adenosine A(1) (CPA), A(2A) (CGS21680C), A(2B) (NECA), and A(3) (2-Cl-IB-MECA) receptor agonists concentration-dependently increased HPOC proliferation. Agonist-induced HPOC proliferation was prevented by their selective antagonists, DPCPX, SCH442416, PSB603, and MRS1191. CPA and NECA facilitated osteogenic differentiation measured by increases in alkaline phosphatase (ALP) activity. This contrasts with the effect of CGS21680C which delayed HPOC differentiation; 2-Cl-IB-MECA was devoid of effect. Blockade of the A(2B) receptor with PSB603 prevented osteogenic differentiation by NECA. In the presence of the A(1) antagonist, DPCPX, CPA reduced ALP activity at 21 and 28 days in culture. At the same time points, blockade of A(2A) receptors with SCH442416 transformed the inhibitory effect of CGS21680C into facilitation. Inhibition of adenosine uptake with dipyridamole caused a net increase in osteogenic differentiation. The presence of all subtypes of adenosine receptors on HPOC was confirmed by immunocytochemistry. Data show that adenosine is an important regulator of osteogenic cell differentiation through the activation of subtype-specific receptors. The most abundant A(2B) receptor seems to have a consistent role in cell differentiation, which may be balanced through the relative strengths of A(1) or A(2A) receptors determining whether osteoblasts are driven into proliferation or differentiation. Copyright © 2010 Wiley-Liss, Inc.

Coupling of UDP-glucuronosyltransferases and multidrug resistance-associated proteins is responsible for the intestinal disposition and poor bioavailability of emodin

Energy Technology Data Exchange (ETDEWEB)

Liu, Wei; Feng, Qian; Li, Ye; Ye, Ling [Department of Pharmaceutics, School of Pharmaceutical Sciences, Southern Medical University, Guangzhou, Guangdong (China); Hu, Ming, E-mail: mhu@uh.edu [Department of Pharmaceutics, School of Pharmaceutical Sciences, Southern Medical University, Guangzhou, Guangdong (China); Department of Pharmacological and Pharmaceutical Sciences, College of Pharmacy, University of Houston, 1441 Moursund Street, Houston, TX 77030 (United States); Liu, Zhongqiu, E-mail: liuzq@smu.edu.cn [Department of Pharmaceutics, School of Pharmaceutical Sciences, Southern Medical University, Guangzhou, Guangdong (China)

2012-12-15

Emodin is a poorly bioavailable but promising plant-derived anticancer drug candidate. The low oral bioavailability of emodin is due to its extensive glucuronidation in the intestine and liver. Caco-2 cell culture model was used to investigate the interplay between UDP-glucuronosyltransferases (UGTs) and efflux transporters in the intestinal disposition of emodin. Bidirectional transport assays of emodin at different concentrations were performed in the Caco-2 monolayers with or without multidrug resistance-associated protein (MRP) and breast cancer resistance protein (BCRP) efflux transporter chemical inhibitors. The bidirectional permeability of emodin and its glucuronide in the Caco-2 monolayers was determined. Emodin was rapidly metabolized to emodin glucuronide in Caco-2 cells. LTC4, a potent inhibitor of MRP2, decreased the efflux of emodin glucuronide and also substantially increased the intracellular glucuronide level in the basolateral-to-apical (B–A) direction. MK-571, chemical inhibitor of MRP2, MRP3, and MRP4, significantly reduced the efflux of glucuronide in the apical-to-basolateral (A–B) and B–A directions in a dose-dependent manner. However, dipyridamole, a BCRP chemical inhibitor demonstrated no effect on formation and efflux of emodin glucuronide in Caco-2 cells. In conclusion, UGT is a main metabolic pathway for emodin in the intestine, and the MRP family is composed of major efflux transporters responsible for the excretion of emodin glucuronide in the intestine. The coupling of UGTs and MRP efflux transporters causes the extensive metabolism, excretion, and low bioavailability of emodin. -- Highlights: ► Glucuronidation is the main reason for the poor oral bioavailability of emodin. ► Efflux transporters are involved in the excretion of emodin glucuronide. ► The intestine is the main organ for metabolism of emodin.

Myocardial perfusion scintigraphy with technetium99m-MIBI in the diagnosis of coronary artery disease in women

International Nuclear Information System (INIS)

Peix, A.T.; Chacon, D.; Ponce, F.; Torres, M.; Llerena, L.; Lopez, A.; Cabrera, O.; Maltas, A.M.; Carrillo, R.

2002-01-01

Aim: To assess the value of myocardial perfusion scintigraphy for coronary artery disease (CAD) in women, we compared the results of a technetium99m-methoxy-isobutyl-isonitrile ( 99m Tc-MIBI) scintigraphy with those of a coronary angiography in a group of women referred for evaluation of chest pain. Material and Methods: Twenty women, 15 of them postmenopausal, were included. A 99m Tc-MIBI myocardial scintigraphy with one-day protocol (rest-stress) was performed. When needed, a combined stress (ergometric plus dipyridamole) was used. Both qualitative and quantitative regional uptake analysis was done. In patients with normal coronary arteries and positive myocardial scintigraphies, measurements were made of serum cholesterol and triglycerides (CHOD-PAD enzymatic colorimetric test), and lipoprotein(a) -Lp(a)- (BioSCREEN Lp(a) method). Results: Change in regional uptake (stress/rest) was as follows: during stress 99m Tc-MIBI, 116 segments had normal uptake (from 93±9% to 94±7%), 52 had moderately reduced uptake (from 67±9% to 75±17%), and 12 had severely reduced uptake (from 33±9% to 64±28%). Qualitative and quantitative analysis coincided in 18 cases. The two non-coincident cases were patients in whom qualitative analysis and coronary angiography were normal, but on quantitative analysis it appeared a reversible defect in one case and a 'reverse redistribution' pattern in the other. Breast attenuation defects were detected in four cases. Myocardial scintigraphy and coronary angiography coincided in 70% cases (figure). The remainder 30% was constituted by patients with positive scintigraphy and normal coronary arteries; among these cases, the 71% were postmenopausal and had systolic hypertension, chest pain at rest, positive ergometric test and hypercholesterolemia (table). Conclusion: We concluded that 99m Tc-MIBI myocardial scintigraphy can help in the CAD diagnosis in postmenopausal women

[Myocardial microcirculation in humans--new approaches using MRI].

Science.gov (United States)

Wacker, Christian M; Bauer, Wolfgang R

2003-03-01

of this autoregulatory response so far. Our laboratory recently developed different techniques for the assessment of myocardial perfusion, regional myocardial blood volume, and capillary recruitment. These techniques are based on theoretical and physiologic considerations and work mainly without CA. In this article, feasibility and reproducibility of these approaches are shown in volunteers and patients. MR exams were performed on a 1.5-T whole body scanner (SIEMENS Vision) and a 2-T system (BRUKER Tomikon). Stress examinations were done repeatedly under pharmacologically induced stress (dipyridamole or adenosine, infusion rate: 0.56 mg/kg body weight over 4 min via an antecubital vein). Heart rate and blood pressure were continuously monitored during stress exams. T1 Spin labeling used in this work is based on T1 measurements after global and slice-selective spin preparation using a fast ECG-gated saturation recovery FLASH sequence. Due to the inflow of unsaturated proton spins, T1 in tissue is shortened after slice-selective preparation case compared to global saturation. We showed that, assuming a two compartment model with fast proton exchange between the compartments, the absolute perfusion P (in [ml/g/min]) can be calculated as P = lambda/T1(blood) ([T1(global)/T1(selective)] - 1), where the blood tissue partition coefficient lambda represents the quotient of water content of capillary blood and perfused tissue, which is approximately 0.9 ml/g in myocardial tissue. T1(blood) is the longitudinal relaxation time T1 of the arterial blood, measured in the left ventricle (LV). T1(global) and T1(selective) are the myocardial T1 calculated after the respective spin preparation. Perfusion reserve is evaluated as the quotient of perfusion under adenosine-induced stress and perfusion at rest. In volunteers quantitative perfusion was determined as 2.5 +/- 0.7 ml/g/min (rest), perfusion reserve was about 2.0. Absolute perfusion decreased to 1.6 +/- 0.6 ml/g/min under

Comparison of 99mTc-MIBI Myocardial Uptake at Rest with Reinjection and 24-hour after Reinjection Images of 201T1

International Nuclear Information System (INIS)

Bom, Hee Seung; Kim, Ji Yeul; Park, Joo Hyung; Ahn, Young Keun; Jeong, Myung Ho; Cho, Jeong Gwan; Park, Jong Choon; Kang, Jung Chaee

1992-01-01

Clinical role of 99m Tc-MIBI myocardial scintigraphy in the diagnosis of coronary artery disease (CAD) is now well accepted, however, the role of it in the identification of viable myocardium in patients with chronic CAD has not yet been clarified. To determine the usefulness of rest-injected 99m Tc-MIBI scan as a marker of myocardial viability, the regional uptake of this agent at rest was compared with that of '2 01 T1 on reinjection and 24 hours after reinjection images. Subject patients were 13 chronic CAD patients who showed irreversible perfusion defect(s) on standard pharmacologic (dipyridamole) stress-redistribution images. Immediately after the redistribution images were obtained, 37 MBq thallium was injected at rest, and images were reacquired at 10 minutes and 24 hours after reinjection. After then 740 MBq 99m Tc-MIBI was injected, and 1 hour later rest MIBI myocardial imaging was performed. Five sets of images (stress, redistribution, reinjection, delayed images of thallium, and rest image of MIBI) were then analyzed qualitatively and quantitatively. Left ventricle was arbitrarily divided into 9 segments (apex, basal and apical portions of anterior, septal, inferior, and lateral walls). Seven patients and 30 regions showed a fixed perfusion defect on the stress-redistribution images. Among 30 regions, 15 showed positive uptakes and 6 showed negative uptakes on both 201 T1 reinjection/delayed images and 99m Tc-MIBI rest images. Five regions showed only thallium uptake and were regarded as viable clinically. Of four regions which showed only 99m Tc-MIBI uptake, two were regarded as viable, while the other two were regarded as a nonviable scar tissue clinically. In conclusion, 201 T1 reinjection technique was more reliable in the identification of viable myocardium. However, the role of 99m Tc-MIBI in identification of viable myocardium was still remained to be clarified because 2 of 9 regions showed only 99m Tc-MIBI uptake and were regarded as viable

Fluorescence Polarization Screening Assays for Small Molecule Allosteric Modulators of ABL Kinase Function.

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Grover, Prerna; Shi, Haibin; Baumgartner, Matthew; Camacho, Carlos J; Smithgall, Thomas E

2015-01-01

The ABL protein-tyrosine kinase regulates intracellular signaling pathways controlling diverse cellular processes and contributes to several forms of cancer. The kinase activity of ABL is repressed by intramolecular interactions involving its regulatory Ncap, SH3 and SH2 domains. Small molecules that allosterically regulate ABL kinase activity through its non-catalytic domains may represent selective probes of ABL function. Here we report a screening assay for chemical modulators of ABL kinase activity that target the regulatory interaction of the SH3 domain with the SH2-kinase linker. This fluorescence polarization (FP) assay is based on a purified recombinant ABL protein consisting of the N-cap, SH3 and SH2 domains plus the SH2-kinase linker (N32L protein) and a short fluorescein-labeled probe peptide that binds to the SH3 domain. In assay development experiments, we found that the probe peptide binds to the recombinant ABL N32L protein in vitro, producing a robust FP signal that can be competed with an excess of unlabeled peptide. The FP signal is not observed with control N32L proteins bearing either an inactivating mutation in the SH3 domain or enhanced SH3:linker interaction. A pilot screen of 1200 FDA-approved drugs identified four compounds that specifically reduced the FP signal by at least three standard deviations from the untreated controls. Secondary assays showed that one of these hit compounds, the antithrombotic drug dipyridamole, enhances ABL kinase activity in vitro to a greater extent than the previously described ABL agonist, DPH. Docking studies predicted that this compound binds to a pocket formed at the interface of the SH3 domain and the linker, suggesting that it activates ABL by disrupting this regulatory interaction. These results show that screening assays based on the non-catalytic domains of ABL can identify allosteric small molecule regulators of kinase function, providing a new approach to selective drug discovery for this important

Stress/Rest Tc-99m-MIBI SPECT in Comparison with Rest/Stress Rubidium - 82 PET

International Nuclear Information System (INIS)

Lee, D. S.; Kamg, K. W.; Lee, K. H.; Jeong, J. M.; Kwark, C. E.; Chung, J. K.; Lee, M.C.; Seo, J. D.; Koh, C. S.

1995-01-01

We compared stress/rest myocardial Tc-99m-MIBI tomographic image findings with rest/stress rubidium-82 tomographic images. In 23 patients with coronary artery disease (12 of them received bypass grafts before) and 6 normal subjects, rest rubidium PET study was performed, rubidium-82 and Tc-99m-MIBI were injected simultaneously to each patient after dipyridamole stress for rubidium PET and MIBI SPECT; and rest MIBI SPECT was performed 4 hours thereafter. We scored segmental decrease of rubidium, or MIBI uptakes into 5 grades for 29 segments from 3 short-axis, vertical and horizontal slices. Scores were summed for each major arterial territory. When more score than two grade-2's or one grade-3 was considered as the cue for significant stenosis for major arterial territories, 67% of 46 stenosed arteries were found with MIBI studies and 78% of them by rubidium studies. Fourteen among 28 grafted arterial territories of 12 post-CABG patients were found normal with both rubidium and MIBI. Segmental scores were concordant between rubidium and MIBI in 72% of 709-stress segments and in 80% of 825 rest segments. Stress rubidium segmental scores were less than stress MIBI scores in 9%, so were rest rubidium scores. Stress rubidium scores were more than stress MIBI scores in 20% of segments, and rest rubidium segmental scores were more than rest MIBI scores in 11%. Rank correlations (Spearman's rho's more than 0.7(stress) and 0.5(rest), slopes (MIBI/rubidium) around 0.7(stress) and 0.9(rest) suggested deeper and wider defects in stress with rubidium. Slope over 1 (MIBI/rubidium) with LAD segmental scores at rest and 7 territories which had much larger score with MIBI revealed exaggeration of rest defects with rest MIBI in same-day stress/rest study. Difference scores (stress-rest for each territory) suggesting ischemia were larger with rubidium (slope of MIBI/rubidium around 0.45). As has been implied by animal or separate-day- human studies, these segmental analyses with

Concomitant intake of alcohol may increase the absorption of poorly soluble drugs.

Science.gov (United States)

Fagerberg, Jonas H; Sjögren, Erik; Bergström, Christel A S

2015-01-25

Ethanol can increase the solubility of poorly soluble and hence present a higher drug concentration in the gastrointestinal tract. This may produce a faster and more effective absorption resulting in variable and/or high drug plasma concentrations, both of which can lead to adverse drug reactions. In this work we therefore studied the solubility and absorption effects of nine diverse compounds when ethanol was present. The apparent solubility was measured using the μDiss Profiler Plus (pION, MA) in four media representing gastric conditions with and without ethanol. The solubility results were combined with in-house data on solubility in intestinal fluids (with and without ethanol) and pharmacokinetic parameters extracted from the literature and used as input in compartmental absorption simulations using the software GI-Sim. Apparent solubility increased more than 7-fold for non-ionized compounds in simulated gastric fluid containing 20% ethanol. Compounds with weak base functions (cinnarizine, dipyridamole and terfenadine) were completely ionized at the studied gastric pH and their solubility was therefore unaffected by ethanol. Compounds with low solubility in intestinal media and a pronounced solubility increase due to ethanol in the upper gastric compartments showed an increased absorption in the simulations. The rate of absorption of the acidic compounds indomethacin and indoprofen was slightly increased but the extent of absorption was unaffected as the complete doses were readily absorbed even without ethanol. This was likely due to a high apparent solubility in the intestinal compartment where the weak acids are ionized. The absorption of the studied non-ionizable compounds increased when ethanol was present in the gastric and intestinal media. These results indicate that concomitant intake of alcohol may significantly increase the solubility and hence, the plasma concentration for non-ionizable, lipophilic compounds with the potential of adverse drug

Usefulness of {sup 201}Tl myocardial perfusion SPECT in prediction of left ventricular remodeling following an acute myocardial infarction

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Yoon, Seok Nam; Park, C. H.; Hwang, Kyung Hoon [Ajou Univ. College of Medicine, Suwon (Korea, Republic of)

2000-02-01

We investigated the role of myocardial perfusion SPECT in prediction of ventricular dilatation and the role of revascularization including thrombolytic therapy and PTCA in prevention of ventricular dilatation after an acute myocardial linfarction (AMI). We performed dipyridamole stress, 4 hour redistribution, and 24 hour reinjection Tl-201 SPECT in 6 patients with AMI two to nine days after attack. Perfusion and wall motion abnormalities were quantified by perfusion index(PI) and wall motion index (WMI). Left ventricular ejection fraction (LVEF), WMI and ventricular volume were measured within 1 week of AMI and after average of 6 months. According to serial changes of left ventricular end-diastolic volume (LVEDV), patients were divided into two groups. We compared WMI, PI and LVEF between the two groups. Relationships among degree of volume, stress-rest PI, WMI, CKMB,Q wave, LVEF and revascularization were analysed using multivariate analysis. Only initial rest perfusion index was significantly different between the two groups (p<0.05). While initial LVEF, stress PI, CKMB, trial of revascularization procedure, presence of Q wave and WMI were not significantly different between the two groups. Eight of 16 patients (50%) showed LV dilatation on follow-up echocardiography. Three of 3 patients (100%) who did not undergo revascualrization procedure documented LV dilatation. And only 5 (38%) of the remaining 13 patients who underwent revascularization revealed LV dilatation. There was no difference in infarct location between the two groups. By multivariate linear regression analysis in patients only undergoing revascularization, rest perfusion index was the only significant factor. Myocardial perfusion SPECT performed prior to revascularization was useful in prediction of LV dilatation after an AMI. Rest perfusion index on myocardial perfusion plays as a significant predictor of left ventricular dilatation after AMI. And revascularization appears to be a valuable

Prognostic value of myocardial perfusion SPECT imaging in elderly patients without history of coronary artery disease and low prevalence of them

International Nuclear Information System (INIS)

Arja, V.J.; Balestrini, V.R.; Sandrin, A.L.; Conci, E.C.; Serra, C.M.; Joekes, S.

2002-01-01

Elderly patients without history of coronary artery disease are difficult to characterized because the clinical symptoms are often atypical, occult or absent. On the other hand, these patients frequently cannot achieve adequate level of exercise during stress testing and this limitation can compromise the diagnostic and prognostic ability of the test. Generally the prognostic value of myocardial perfusion SPECT is well established for a general population but not for elderly patients. Aim: This study assessed the prognostic value of Tc99m-sestamibi SPECT in a group of patients older than 65 years with low prevalence of coronary artery disease. Material and Methods: Population: 161 consecutive patients older than 65 years without history of coronary artery disease and low prevalence of them were studied with Tc99m-sestamibi SPECT perfusion imaging. Mean age 71 years old (65-87), male 55%, mean pretest likelihood 11%. Risk factors: diabetes 17%, high blood pressure 74%, high cholesterol 45%, smokers 88%. Stress test: bicycle exercise 39% and dipyridamole 61%. Myocardial perfusion SPECT: semiquantitative analysis to evaluate perfusion defects with a 14-segments model and 4-point scoring system for uptake reduction. Scintigraphic indices: SSS (sum of the stress scores), SRS (sum of the rest scores) and SDS (SSS-SRS). Follow up: cardiac events: hard (acute myocardial infarction and cardiac death) and soft (need for PTCA/CABG and angina). Results: Mean follow up: 508 days. Events rate: hard 0.6% (1 acute myocardial infarction), soft 5.6%. Univariate analysis identified sex (p=0.017) and SDS (p=0.009) as cardiac events predictors. Complete or reduced (independent variables which predicted events) logistic regression analysis correctly predicted the absence of events but did not predict the presence of events. Conclusion: In this elderly population with a low clinical risk where the stress test is a suboptimal method of study for coronary artery disease, semiquantitative

Myocardial perfusion SPECT 2015 in Germany. Results of the 7th survey.

Science.gov (United States)

Lindner, Oliver; Burchert, Wolfgang; Schäfer, Wolfgang; Hacker, Marcus

2017-02-14

The working group Cardiovascular Nuclear Medicine of the German Society of Nuclear Medicine presents the results of the 7th survey of myocardial perfusion SPECT (MPS) of the reporting year 2015. 268 questionnaires (173 practices [PR], 67 hospitals [HO], 28 university hospitals [UH]) were evaluated. Results of the last survey from 2012 are set in squared brackets. MPS of 121 939 [105 941] patients were reported. 98 % [95 %] of all MPS were performed with Tc-99m radiopharmaceuticals and 2 % [5 %] with Tl-201. 78 % [79 %] of all patients were studied in PR, 14 % [15 %] in HO, and 8 % [6 %] in UH. A pharmacological stress test was performed in 43 % [39 %] (22 % [24 %] adenosine, 20 % [9 %] regadenoson, 1 % [6 %] dipyridamole or dobutamine). Attenuation correction was applied in 25 % [2009: 10 %] of MPS. Gated SPECT was performed in 78 % [70 %] of all rest MPS, in 80 % [73 %] of all stress and in 76 % [67 %] of all stress and rest MPS. 53 % [33 %] of all nuclear medicine departments performed MPS scoring by default, whereas 24 % [41 %] did not apply any quantification. 31 % [26 %] of all departments noticed an increase in their counted MPS and 29 % [29 %] no changes. Data from 89 departments which participated in all surveys showed an increase in MPS count of 11.1 % (PR: 12.2 %, HO: 4.8 %, UH: 18.4 %). 70 % [60 %] of the MPS were requested by ambulatory care cardiologists. The 2015 MPS survey reveals a high-grade adherence of routine MPS practice to current guidelines. The positive trend in MPS performance and number of MPS already observed in 2012 continues. Educational training remains necessary in the field of SPECT scoring.

A comparative study between TL-201 SPECT myocardial perfusion scintigraphy and dobutamine stress echocardiography in the detection of coronary artery disease at the Philippine Heart Center

International Nuclear Information System (INIS)

Ogbac, R.V.; Martinez, A.O.; Obaldo, J.M.; Monzon, O.P.; Torres, J.F.; Rondilla, L.W.S.; Yap, J.S.; Flores, V.B.; Santos, R.J.; Jara, R.D.

1996-01-01

Although thallium-201 SPECT myocardial perfusion scintigraphy (MPS) has shown considerable accuracy for the detection of coronary artery disease (CAD), dobutamine stress echocardiography (DSE), a relatively new method for the detection of CAD had been recently utilized at the Philippine Heart Center. To assess its diagnostic worth versus that of thallium-201 spect myocardial scintigraphy (MPS), we studied 18 patients who underwent both procedures. Coronary angiography (CA) was used as the gold standard. MPS was performed with maximal treadmill exercise or with dipyridamole (0.568 mg/kg over 4 minutes) and Tl-201 was injected at peak stress. DSE was performed by infusing dobutamine at an increment of 5 μg/kg/min up to a maximum of 40. Atropine (0.01%) was added when 85% of maximum predicted heart rate is not achieved. Significant stenosis (>70%) was found in 16 out of 18 patients by CA. The sensitivity for the presence of CAD was 88% (14/16) and 69% (11/16) for MPS and DSE respectively. Specificity was 100% (2/2) for both. PPV was 100% for both while NPV was 50% and 29% for MPS and DSE respectively. Diagnostic accuracies were 89% and 72% for MPS and DSE respectively (P>0.05). Sensitivity for detecting left anterior descending artery (LAD) lesion was 71% 64% for MPS and DSE respectively; specificity was 75% and 100% respectively. For the left circumplex artery (LCX) lesion, both MPS and DSE had a sensitivity of 62% and specificity of 60%. Likewise for the right coronary artery (RCA) lesion, both had a sensitivity of 66% and specificity of 50%. Diagnostic accuracies were equal for both tests at 72% for LAD; 61% for LCX; and 61% for RCA. Kappa tests for association shows ρ values of >0.05 for overall and individual CAD detection suggesting no significant difference between MPS and DSE. Although there is a trend showing better detection of CAD with MPS, this particular study shows that both tests are comparable with regards to detection of the presence of CAD and of

A semi-quantitative translational pharmacology analysis to understand the relationship between in vitro ENT1 inhibition and the clinical incidence of dyspnoea and bronchospasm

International Nuclear Information System (INIS)

Rosenbrier Ribeiro, Lyn; Ian Storer, R.

2017-01-01

Adenosine contributes to the pathophysiology of respiratory disease, and adenosine challenge leads to bronchospasm and dyspnoea in patients. The equilibrative nucleoside transporter 1 (ENT1) terminates the action of adenosine by removal from the extracellular environment. Therefore, it is proposed that inhibition of ENT1 in respiratory disease patients leads to increased adenosine concentrations, triggering bronchospasm and dyspnoea. This study aims to assess the translation of in vitro ENT1 inhibition to the clinical incidence of bronchospasm and dyspnoea in respiratory disease, cardiovascular disease and healthy volunteer populations. Four marketed drugs with ENT1 activity were assessed; dipyridamole, ticagrelor, draflazine, cilostazol. For each patient population, the relationship between in vitro ENT1 [ 3 H]-NBTI binding affinity (K i ) and [ 3 H]-adenosine uptake (IC 50 ) to the incidence of: (1) bronchospasm/severe dyspnoea; (2) tolerated dyspnoea and; (3) no adverse effects, was evaluated. A high degree of ENT1 inhibition (≥ 13.3x K i , ≥ 4x IC 50 ) associated with increased incidence of bronchospasm/severe dyspnoea for patients with respiratory disease only, whereas a lower degree of ENT1 inhibition (≥ 0.1x K i , ≥ 0.05x IC 50 ) associated with a tolerable level of dyspnoea in both respiratory and cardiovascular disease patients. ENT1 inhibition had no effect in healthy volunteers. Furthermore, physicochemical properties correlative with ENT1 binding were assessed using a set of 1625 diverse molecules. Binding to ENT1 was relatively promiscuous (22% compounds K i < 1 μM) especially for neutral or basic molecules, and greater incidence tracked with higher lipophilicity (clogP > 5). This study rationalises inclusion of an assessment of ENT1 activity during early safety profiling for programs targeting respiratory disorders. - Highlights: • ENT1 inhibition causes bronchospasm and severe dyspnoea in respiratory patients. • Neutral or basic

Myocardial blood flow assessment with {sup 82}rubidium-PET imaging in patients with left bundle branch block

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Falcao, Andrea; Chalela, William; Giorgi, Maria Clementina; Imada, Rodrigo; Soares Junior, Jose; Do Val, Renata; Oliveira, Marco Antonio; Izaki, Marisa; Kalil Filho, Roberto; Meneghetti, Jose C., E-mail: andrea.falcao@incor.usp.br [Universidade de Sao Paulo (InCor/USP), Sao Paulo, SP (Brazil). Hospital das Clinicas. Instituto do Coracao

2015-11-15

Objectives: Perfusion abnormalities are frequently seen in Single Photon Emission Computed Tomography (SPECT) when a left bundle branch block is present. A few studies have shown decreased coronary flow reserve in the left anterior descending territory, regardless of the presence of coronary artery disease. Objective: we sought to investigate rubidium-82 ({sup 82}Rb) positron emission tomography imaging in the assessment of myocardial blood flow and coronary flow reserve in patients with left bundle branch block. Methods: thirty-eight patients with left bundle branch block (GI), median age 63.5 years, 22 (58%) female, 12 with coronary artery disease (≥70%; GI-A) and 26 with no evidence of significant coronary artery disease (GI-B), underwent rest-dipyridamole stress {sup 82}Rb-positron emission tomography with absolute quantitative flow measurements using Cedars-Sinai software (mL/min/g). The relative myocardial perfusion and left ventricular ejection fraction were assessed in 17 segments. These parameters were compared with those obtained from 30 patients with normal {sup 82}Rb-positron emission tomography studies and without left bundle branch block (GII). Results: stress myocardial blood flow and coronary flow reserve were significantly lower in GI than in GII (p>0.05). The comparison of coronary flow reserve between GI-A and GI-B showed that it was different from the global coronary flow reserve (p<0.05) and the stress flow was significantly lower in the anterior than in the septal wall for both groups. Perfusion abnormalities were more prevalent in GI-A (p=0.06) and the left ventricular ejection fraction was not different between GI-A and GI-B, whereas it was lower in GI than in GII (p<0.001). Conclusion: the data confirm that patients with left bundle branch block had decreased myocardial blood flow and coronary flow reserve and coronary flow reserve assessed by {sup 82}Rb-positron emission tomography imaging may be useful in identifying coronary artery

Utility of the premature cocked in SPECT of myocardial perfusion with technetium and artery-dilators. Inherent problems and analysis of local preliminary experience

International Nuclear Information System (INIS)

Gutierrez, Daniela; Massardo, Teresa; Jaimovich, Rodrigo; Anzoategui, Wilfredo; Guzman, Alfonso; Lavados, Hugo; Alliende, Isabel

2007-01-01

Using myocardial perfusion studies, severe coronary artery disease (CAD) with left ventricular dysfunction could be observed through transient cavity dilation and radiopharmaceutical lung uptake increase, described initially with stress 201 Tl. Dipyridamole (DIP) induced ischemia also can diminish systolic function. Delayed post stress left ventricular ejection fraction (FEVI) may not be able to detect this phenomena, depending on the acquisition timing. There are diverse reports and results in this issue. Goal: Evaluate the correlation between left ventricular parameters and ischemia presence in early gated DIP tomography in patients referred for CAD evaluation along to review the new protocol difficulties.Methods: From 158 patients evaluated initially, 31% presenting extra-cardiac activity were excluded due to interference with automatic edge detection. The analyzed group included 109 subjects between 33 and 91 years, mean age 64.3 ± 11.7; 52% women. Thirty of them were known CAD patients; 18 with myocardial infarction and 31 with ischemia in perfusion images. 99m Tc-Sestamibi SPECT was carried out during the 60 min post DIP infusion, using 1 day protocol. Cedars QGS QPS Programs were used to measure LVEF and left ventricular volumes. Diastolic transient ischemic dilation (TID) calculation was performed as well as lung/heart index (LHR). Results: The mean time lapse between DIP injection and acquisition was 27 min (range: 18-43 min). There was not significant difference between DIP and rest LVEF (66.55±17.33% vs 67.58±18.41%) LVEF delta was 1.03±6.72%. There was not correlation observed between measured functional parameters and presence of ischemia, infarction or known CAD. There was clear difference in left ventricular volumes in patients with and without CAD and known myocardial infarction. Conclusion: Nor association between LHR, LVEF delta or TID and ischemia was demonstrated in early post DIP SPECT acquisition using Sestamibi. In addition, significant

Prognosis for medically treated elderly patients with coronary artery disease. Analysis by the cox model

International Nuclear Information System (INIS)

Furuno, Takashi; Yamasaki, Fumiyasu; Yabe, Toshikazu; Matsumura, Yoshihisa; Kitaoka, Hiroaki; Doi, Yoshinori

1997-01-01

The prognostic importance of age among well-known prognostic factors such as extent of coronary artery lesions, cardiac function, and myocardial ischemia was evaluated in 147 elderly patients with coronary artery disease aged 65 years or older who underwent dipyridamole perfusion scintigraphy and coronary angiography. After excluding 32 patients who initially underwent percutaneous transluminal coronary angioplasty (PTCA) or coronary artery bypass grafting (CABG), 115 patients who were initially treated medically were analysed by the Cox model for cardiac events during a mean follow-up period of 29±22 months. Among the 114 patients who were available for follow-up, nine patients (7.9%) had cardiac events, including five cardiac deaths and four non-fatal cardiac events (requiring PTCA or CABG). When the 114 patients were divided into three age-groups; 53 patients aged 65-69 years, 42 aged 70-74 years and 19 aged 75 years or older, the incidence of cardiac death was highest in those aged 75 years or older. Univariate analysis showed that age of 70 years or older (hazards ratio 15.15, p=0.004), scintigraphic diffuse slow washout (hazards ratio 8.77, p=0.002), and triple-vessel or left main trunk disease (hazards ratio 6.36, p=0.05) were important prognostic factors. Multivariate analysis showed that scintigraphic diffuse slow washout (hazards ratio 6.33, p=0.05), and triple-vessel or left main trunk disease (hazards ratio 11.94 p=0.05) were statistically significant as independent prognostic factors. However, when age of 70 years or older was included in the analysis, it showed higher hazards ratio (21.21, p=0.03) than that of scintigraphic diffuse slow washout (7.36) or triple-vessel or left main trunk disease (5.30). Age of 70 years or older may be a significant prognostic factor in elderly patients with coronary artery disease which has an equivalent importance to the extent of coronary lesions. (author)

Myocardial blood flow and left ventricular functional reserve in hypertrophic cardiomyopathy: a {sup 13}NH{sub 3} gated PET study

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Sciagra, Roberto; Calabretta, Raffaella; Passeri, Alessandro; Castello, Angelo; Pupi, Alberto [University of Florence, Nuclear Medicine Unit, Department of Experimental and Clinical Biomedical Sciences ' ' Mario Serio' ' , Florence (Italy); Cipollini, Fabrizio [University of Florence, Department of Statistics, Florence (Italy); Cecchi, Franco; Olivotto, Iacopo [Careggi University Hospital, Referral Centre for Myocardial Diseases, Florence (Italy)

2017-05-15

Ischemia in hypertrophic cardiomyopathy (HCM) is caused by coronary microvascular dysfunction (CMD), which is detected by measuring myocardial blood flow (MBF) with PET. Whether CMD may be associated with ischemic left ventricular (LV) dysfunction is unclear. We therefore assessed LV ejection fraction (EF) reserve in HCM patients undergoing dipyridamole (Dip) PET. Resting and stress {sup 13}NH{sub 3} dynamic as well as gated PET were performed in 34 HCM patients. Segmental MBF and transmural perfusion gradient (TPG = subendocardial / subepicardial MBF) were assessed. LVEF reserve was considered abnormal if Dip LVEF decreased more than 5 units as compared to rest. Eighteen patients had preserved (group A) and 16 abnormal LVEF reserve (group B; range -7 to -32). Group B patients had greater wall thickness than group A, but resting volumes, LVEF, resting and Dip MBF, and myocardial flow reserve were similar. Group B had slightly higher summed stress score and summed difference score in visual analysis than group A, and a significantly higher summed stress wall motion score. In group B, resting TPG was slightly lower (1.31 ± 0.29 vs. 1.37 ± 0.34, p <0.05), and further decreased after Dip, whilst in group A it increased (B = 1.20 ± 0.39, p < 0.0001 vs. rest and vs. A = 1.40 ± 0.43). The number of segments per patient with TPG <1 was higher than in group A (p < 0.001) and was a significant predictor of impaired LVEF reserve (OR 1.86, p < 0.02), together with wall thickness (OR 1.3, p < 0.02). Abnormal LVEF response is common in HCM patients following Dip, and is related to abnormal TPG, suggesting that subendocardial ischemia might occur under Dip and cause transient LV dysfunction. Although in vivo this effect may be hindered by the adrenergic drive associated with effort, these findings may have relevance in understanding exercise limitation and heart failure symptoms in HCM. (orig.)

Quantitation of myocardial blood flow and myocardial flow reserve with 99mTc-sestamibi dynamic SPECT/CT to enhance detection of coronary artery disease

International Nuclear Information System (INIS)

Hsu, Bailing; Chen, Fu-Chung; Chen, Chien-Cheng; Wu, Tao-Cheng; Huang, Wen-Sheng; Hou, Po-Nien; Hung, Guang-Uei

2014-01-01

Conventional dual-head single photon emission computed tomography (SPECT)/CT systems capable of fast dynamic SPECT (DySPECT) imaging have a potential for flow quantitation. This study introduced a new method to quantify myocardial blood flow (MBF) and myocardial flow reserve (MFR) with DySPECT scan and evaluated the diagnostic performance of detecting coronary artery disease (CAD) compared with perfusion using invasive coronary angiography (CAG) as the reference standard. This study included 21 patients with suspected or known CAD who had received DySPECT, ECG-gated SPECT (GSPECT), and CAG (13 with ≥50 % stenosis in any vessel; non-CAD group: 8 with patent arteries or 99m Tc-sestamibi (MIBI) tracer at rest or dipyridamole-stress stages. DySPECT images were reconstructed with full physical corrections and converted to the physical unit of becquerels per milliliter. Stress MBF (SMBF), rest MBF (RMBF), and MFR were quantified by a one-tissue compartment flow model using time-activity curves derived from DySPECT images. Perfusion images were processed for GSPECT scan and interpreted to obtain summed stress score (SSS) and summed difference score (SDS). Receiver-operating characteristic (ROC) analyses were conducted to evaluate the diagnostic performance of flow and perfusion. Using the criteria of ≥50 % stenosis as positive CAD, areas under the ROC curve (AUCs) of flow assessment were overall significantly greater than those of perfusion. For patient-based analysis, AUCs for MFR, SMBF, SSS, and SDS were 0.91 ± 0.07, 0.86 ± 0.09, 0.64 ± 0.12, and 0.59 ± 0.13. For vessel-based analysis, AUCs for MFR, SMBF, SSS, and SDS were 0.81 ± 0.05, 0.76 ± 0.06, 0.62 ± 0.07, and 0.56 ± 0.08, respectively. The preliminary data suggest that MBF quantitation with a conventional SPECT/CT system and the flow quantitation method is a clinically effective approach to enhance CAD detection. (orig.)

Myocardial blood flow assessment with 82rubidium-PET imaging in patients with left bundle branch block

International Nuclear Information System (INIS)

Falcao, Andrea; Chalela, William; Giorgi, Maria Clementina; Imada, Rodrigo; Soares Junior, Jose; Do Val, Renata; Oliveira, Marco Antonio; Izaki, Marisa; Kalil Filho, Roberto; Meneghetti, Jose C.

2015-01-01

Objectives: Perfusion abnormalities are frequently seen in Single Photon Emission Computed Tomography (SPECT) when a left bundle branch block is present. A few studies have shown decreased coronary flow reserve in the left anterior descending territory, regardless of the presence of coronary artery disease. Objective: we sought to investigate rubidium-82 ( 82 Rb) positron emission tomography imaging in the assessment of myocardial blood flow and coronary flow reserve in patients with left bundle branch block. Methods: thirty-eight patients with left bundle branch block (GI), median age 63.5 years, 22 (58%) female, 12 with coronary artery disease (≥70%; GI-A) and 26 with no evidence of significant coronary artery disease (GI-B), underwent rest-dipyridamole stress 82 Rb-positron emission tomography with absolute quantitative flow measurements using Cedars-Sinai software (mL/min/g). The relative myocardial perfusion and left ventricular ejection fraction were assessed in 17 segments. These parameters were compared with those obtained from 30 patients with normal 82 Rb-positron emission tomography studies and without left bundle branch block (GII). Results: stress myocardial blood flow and coronary flow reserve were significantly lower in GI than in GII (p>0.05). The comparison of coronary flow reserve between GI-A and GI-B showed that it was different from the global coronary flow reserve (p<0.05) and the stress flow was significantly lower in the anterior than in the septal wall for both groups. Perfusion abnormalities were more prevalent in GI-A (p=0.06) and the left ventricular ejection fraction was not different between GI-A and GI-B, whereas it was lower in GI than in GII (p<0.001). Conclusion: the data confirm that patients with left bundle branch block had decreased myocardial blood flow and coronary flow reserve and coronary flow reserve assessed by 82 Rb-positron emission tomography imaging may be useful in identifying coronary artery disease in patients

Comparison of exercise and pharmacological stress gated SPECT in detecting transient left ventricular dysfunction.

Science.gov (United States)

Demir, Hakan; Tan, Yusuf Z; Isgoren, Serkan; Gorur, Gozde D; Kozdag, Guliz; Ural, Ertan; Berk, Fatma

2008-06-01

Transient left ventricular contractile dysfunction (TLVD) is observed owing to post-exercise stunning in patients with coronary artery disease (CAD). Pharmacological stimulation differs from exercise stress because it does not cause demand ischemia. The aim of this study was to determine whether TLVD could also be seen after pharmacological stress (dipyridamole). Of the patients in whom gated single-photon emission computed tomography (GSPECT) was performed in our institution from January 2004 to April 2007, 439 subjects with known or suspected CAD were included in the study. GSPECT was performed for all patients following exercise (group I, n = 220) or pharmacological stress (group II, n = 219) according to a 2-day (stress-rest) protocol after injection of Tc-99m methoxyisobutyl-isonitrile (MIBI). Stress, rest, and difference (stress-rest value) left ventricular ejection fractions (SLVEF, RLVEF, and DLVEF) and transient ischemic dilatation (TID) ratio were derived automatically. Summed stress score, summed rest score, and summed difference score (SDS) for myocardial perfusion were calculated using a 20-segment model and a five-point scoring system. An SDS > 3 was considered as ischemic. On the basis of the perfusion findings, patients were subdivided into a normal (group A, n = 216) and ischemia group (group B, n = 223). DLVEF and perfusion scores of all groups were compared. Relationships between DLVEF and perfusion, and between TID ratio and DLVEF were also evaluated. Stress-induced ischemia was observed in 223 of 439 patients (50.8%). In group A, the difference between stress and rest LVEF values was not significant (P = 0.670 and P = 0.200 for groups IA and IIA, respectively). However, LVEF was significantly decreased after stress compared with rest values for group B (P good correlations between TID ratios and DLVEF values in four subgroups (r = -0.55, r = -0.62, r = -0.59, and r = -0.41; for groups IA, IB, IIA, and IIB, respectively, P stress was observed

Role of adenosine A2A receptor signaling in the nicotine-evoked attenuation of reflex cardiac sympathetic control

International Nuclear Information System (INIS)

El-Mas, Mahmoud M.; El-gowilly, Sahar M.; Fouda, Mohamed A.; Saad, Evan I.

2011-01-01

Baroreflex dysfunction contributes to increased cardiovascular risk in cigarette smokers. Given the importance of adenosinergic pathways in baroreflex control, the hypothesis was tested that defective central adenosinergic modulation of cardiac autonomic activity mediates the nicotine-baroreflex interaction. Baroreflex curves relating changes in heart rate (HR) to increases or decreases in blood pressure (BP) evoked by i.v. doses (1-16 μg/kg) of phenylephrine (PE) and sodium nitroprusside (SNP), respectively, were constructed in conscious rats; slopes of the curves were taken as measures of baroreflex sensitivity (BRS). Nicotine (25 and 100 μg/kg i.v.) dose-dependently reduced BRS SNP in contrast to no effect on BRS PE . BRS SNP was also attenuated after intracisternal (i.c.) administration of nicotine. Similar reductions in BRS SNP were observed in rats pretreated with atropine or propranolol. The combined treatment with nicotine and atropine produced additive inhibitory effects on BRS, an effect that was not demonstrated upon concurrent exposure to nicotine and propranolol. BRS SNP was reduced in preparations treated with i.c. 8-phenyltheophylline (8-PT, nonselective adenosine receptor antagonist), 8-(3-Chlorostyryl) caffeine (CSC, A 2A antagonist), or VUF5574 (A 3 antagonist). In contrast, BRS SNP was preserved after blockade of A 1 (DPCPX) or A 2B (alloxazine) receptors or inhibition of adenosine uptake by dipyridamole. CSC or 8-PT abrogated the BRS SNP depressant effect of nicotine whereas other adenosinergic antagonists were without effect. Together, nicotine preferentially impairs reflex tachycardia via disruption of adenosine A 2A receptor-mediated facilitation of reflex cardiac sympathoexcitation. Clinically, the attenuation by nicotine of compensatory sympathoexcitation may be detrimental in conditions such as hypothalamic defense response, posture changes, and ventricular rhythms. - Research highlights: → The role of central adenosinergic sites in

Fluorescence Polarization Screening Assays for Small Molecule Allosteric Modulators of ABL Kinase Function.

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Prerna Grover

Full Text Available The ABL protein-tyrosine kinase regulates intracellular signaling pathways controlling diverse cellular processes and contributes to several forms of cancer. The kinase activity of ABL is repressed by intramolecular interactions involving its regulatory Ncap, SH3 and SH2 domains. Small molecules that allosterically regulate ABL kinase activity through its non-catalytic domains may represent selective probes of ABL function. Here we report a screening assay for chemical modulators of ABL kinase activity that target the regulatory interaction of the SH3 domain with the SH2-kinase linker. This fluorescence polarization (FP assay is based on a purified recombinant ABL protein consisting of the N-cap, SH3 and SH2 domains plus the SH2-kinase linker (N32L protein and a short fluorescein-labeled probe peptide that binds to the SH3 domain. In assay development experiments, we found that the probe peptide binds to the recombinant ABL N32L protein in vitro, producing a robust FP signal that can be competed with an excess of unlabeled peptide. The FP signal is not observed with control N32L proteins bearing either an inactivating mutation in the SH3 domain or enhanced SH3:linker interaction. A pilot screen of 1200 FDA-approved drugs identified four compounds that specifically reduced the FP signal by at least three standard deviations from the untreated controls. Secondary assays showed that one of these hit compounds, the antithrombotic drug dipyridamole, enhances ABL kinase activity in vitro to a greater extent than the previously described ABL agonist, DPH. Docking studies predicted that this compound binds to a pocket formed at the interface of the SH3 domain and the linker, suggesting that it activates ABL by disrupting this regulatory interaction. These results show that screening assays based on the non-catalytic domains of ABL can identify allosteric small molecule regulators of kinase function, providing a new approach to selective drug discovery

Significant regional heterogeneity of coronary flow reserve in paediatric hypertrophic cardiomyopathy

International Nuclear Information System (INIS)

Tadamura, E.; Kudoh, T.; Kubo, S.; Konishi, J.; Motooka, M.; Nohara, R.; Matsumori, A.; Sasayama, S.; Matsuda, T.; Tamaki, N.

2000-01-01

Previous studies have indicated that cardiac events in young patients with hypertrophic cardiomyopathy (HCM) are related to ischaemia rather than to arrhythmia. We measured coronary flow reserve in paediatric HCM and compared the values with those in adult HCM. We studied 12 patients with HCM including six paediatric ( 20 years old: mean 62 years), and six healthy young adults (mean 29 years) as controls. Every patient underwent magnetic resonance imaging (MRI) for anatomical assessment. Myocardial blood flow at rest and after dipyridamole infusion was measured with dynamic nitrogen-13 ammonia positron emission tomography (PET). Partial volume effect was corrected for using the anatomical data obtained with MRI. In adult patients with HCM, coronary flow reserve in the hypertrophied septal region was not significantly different from that in the non-hypertrophied lateral wall (1.38±0.29 vs 1.77±0.39, respectively). In the paediatric patients, coronary flow reserve in the hypertrophied septal region was significantly lower than in the non-hypertrophied lateral wall (0.84±0.33 vs 2.74±0.90, respectively, P<0.01). In addition, coronary flow reserve in adult patients was lower than in control subjects both in the septal wall (1.38±0.29 vs 2.94±0.35, respectively, P<0.0001) and in the lateral wall (1.77±0.39 vs 2.85±0.69, respectively, P<0.05). In contrast, coronary flow reserve in paediatric patients was not significantly different from that in control subjects in the lateral wall (2.74±0.90 vs 2.85±0.69, respectively), while absolute reduction of myocardial blood flow was noted after pharmacological vasodilatation in the hypertrophied septal region. In conclusion, significant regional differences of coronary flow reserve were present in the paediatric patients with HCM. These results suggest that paediatric patients with HCM intrinsically have the potential to experience significant regional ischaemia even in the absence of coronary stenosis. (orig.)

The research on endothelial function in women and men at risk for cardiovascular disease (REWARD study: methodology

Directory of Open Access Journals (Sweden)

Lavoie Kim L

2011-08-01

Full Text Available Abstract Background Endothelial function has been shown to be a highly sensitive marker for the overall cardiovascular risk of an individual. Furthermore, there is evidence of important sex differences in endothelial function that may underlie the differential presentation of cardiovascular disease (CVD in women relative to men. As such, measuring endothelial function may have sex-specific prognostic value for the prediction of CVD events, thus improving risk stratification for the overall prediction of CVD in both men and women. The primary objective of this study is to assess the clinical utility of the forearm hyperaemic reactivity (FHR test (a proxy measure of endothelial function for the prediction of CVD events in men vs. women using a novel, noninvasive nuclear medicine -based approach. It is hypothesised that: 1 endothelial dysfunction will be a significant predictor of 5-year CVD events independent of baseline stress test results, clinical, demographic, and psychological variables in both men and women; and 2 endothelial dysfunction will be a better predictor of 5-year CVD events in women compared to men. Methods/Design A total of 1972 patients (812 men and 1160 women undergoing a dipyridamole stress testing were recruited. Medical history, CVD risk factors, health behaviours, psychological status, and gender identity were assessed via structured interview or self-report questionnaires at baseline. In addition, FHR was assessed, as well as levels of sex hormones via blood draw. Patients will be followed for 5 years to assess major CVD events (cardiac mortality, non-fatal MI, revascularization procedures, and cerebrovascular events. Discussion This is the first study to determine the extent and nature of any sex differences in the ability of endothelial function to predict CVD events. We believe the results of this study will provide data that will better inform the choice of diagnostic tests in men and women and bring the quality of

Comparison between exercise electrocardiogram and thallium 201 myocardial perfusion imaging during exercise, after dipyridamole and at rest, for the diagnosis of stable angina pectoris. 176 cases were studied with coronary angiography

International Nuclear Information System (INIS)

Machecourt, J.; Denis, B.; Comet, M.; Wolf, J.E.; Dimitriou, R.; Pellet, J.; Noel, P.M.

1981-01-01

The purpose of this study was to compare the diagnostic interest of the electrocardiogram stress test (EST) and the thallium myocardial imaging during exercise (TIE). For this, the cases of 176 patients with stable angina pectoris who underwent a coronary arteriogram were studied. These patients were divided into two groups: a first group of 113 patients without a previous history of myocardial infarction, nor a Q wave on their electrocardiogram and a second group of 63 patients with angina pectoris after a previous myocardial infarction. All patients underwent a combined EST and TIE. The sensitivity and the specificity of the EST and the TIE were studied, and the post-test risk after either a positive test or a negative test was calculated according to Bayes' theorem. In the first group 62 patients had a coronary stenosis and 51 had a normal arteriogram. The sensitivity of the TIE was higher than that of the EST: 80% versus 64%, p < 0.01. Even when the maximum effort was not reached during the EST, the TIE kept the same sensitivity. The diagnosis of angina pectoris cannot be absolutely established by the separate use of the TIE or the EST. However, their predictive value increases when both are correlated. Moreover, for female patients, the TIE is more specific than the EST because of the higher frequency of false positive or equivocal results of the EST in that population. (Auth.)

Quantitative relationship between coronary vasodilator reserve assessed by {sup 82}Rb PET imaging and coronary artery stenosis severity

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Anagnostopoulos, Constantinos [Brigham and Women' s Hospital, Division of Nuclear Medicine/PET, Boston, MA (United States); Royal Brompton Hospital, Department of Nuclear Medicine, London (United Kingdom); Brigham and Women' s Hospital, Harvard Medical School, London (United Kingdom); Almonacid, Alexandra; Popma, Jeffrey J. [Brigham and Women' s Hospital, Division of Cardiovascular Medicine, Department of Medicine, Boston, MA (United States); Brigham and Women' s Hospital, Harvard Medical School, London (United Kingdom); El Fakhri, Georges [Brigham and Women' s Hospital, Division of Nuclear Medicine/PET, Boston, MA (United States); Royal Brompton Hospital, Department of Cardiology, London (United Kingdom); Curillova, Zelmira; Dorbala, Sharmila; Di Carli, Marcelo F. [Brigham and Women' s Hospital, Division of Nuclear Medicine/PET, Boston, MA (United States); Brigham and Women' s Hospital, Cardiovascular Imaging, Department of Radiology, Boston, MA (United States); Brigham and Women' s Hospital, Division of Cardiovascular Medicine, Department of Medicine, Boston, MA (United States); Brigham and Women' s Hospital, Harvard Medical School, London (United Kingdom); Sitek, Arkadiusz [Brigham and Women' s Hospital, Division of Nuclear Medicine/PET, Boston, MA (United States); Brigham and Women' s Hospital, Harvard Medical School, London (United Kingdom); Roughton, Michael [Royal Brompton Hospital, Department of Cardiology, London (United Kingdom)

2008-09-15

The relationship between myocardial blood flow (MBF) and stenosis severity has been determined previously using cyclotron-produced radiotracers such as {sup 15}O-H{sub 2}O and {sup 13}N-ammonia. An attractive alternative to overcome the limitations related to the use of cyclotron might be to use the generator-produced {sup 82}Rb as a flow tracer. The current study was undertaken to investigate the relationship between MBF and coronary vasodilator reserve (CVR) as measured by {sup 82}Rb positron emission tomography (PET) and the percent diameter stenosis as defined by quantitative coronary arteriography. We prospectively evaluated 22 individuals: 15 patients (60 {+-} 11 years of age) with angiographically documented coronary artery disease (CAD) and seven age-matched (56 {+-} 9 years) asymptomatic individuals without risk factors for CAD. Dynamic {sup 82}Rb PET was performed at rest and after dipyridamole vasodilation. MBF, CVR and an index of 'minimal coronary resistance' (MCR) were assessed in each of the three main coronary territories. Rest and stress MBF in regions subtended by vessels with less than 50% diameter stenosis was similar to that of the individuals with no risk factors for CAD. As a result, CVR was also similar in the two groups (1.9, interquartile [IQ] range from 1.7 to 2.7 vs. 2.2, IQ range from 2 to 3.4 respectively, p=0.09). CVR successfully differentiated coronary lesions with stenosis severity 70% to 89% from those with 50% to 69% stenosis (1, IQ range from 1 to 1.3 vs. 1.7, IQ range from 1.4 to 2), respectively, p=0.001. In addition, hyperaemic MBF (r{sup 2}=0.74, p<0.001), CVR (r {sup 2}=0.69, p<0.001) and MCR (r{sup 2}=0.78, p<0.001) measurements were inversely and non-linearly correlated to the percent diameter stenosis on angiography. MBF and CVR are inversely and non-linearly correlated to stenosis severity. Quantitative {sup 82}Rb PET can be a clinically useful tool for an accurate functional assessment of CAD. (orig.)

A semi-quantitative translational pharmacology analysis to understand the relationship between in vitro ENT1 inhibition and the clinical incidence of dyspnoea and bronchospasm

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Rosenbrier Ribeiro, Lyn, E-mail: Lyn.Rosenbrierribeiro@AstraZeneca.com; Ian Storer, R.

2017-02-15

Adenosine contributes to the pathophysiology of respiratory disease, and adenosine challenge leads to bronchospasm and dyspnoea in patients. The equilibrative nucleoside transporter 1 (ENT1) terminates the action of adenosine by removal from the extracellular environment. Therefore, it is proposed that inhibition of ENT1 in respiratory disease patients leads to increased adenosine concentrations, triggering bronchospasm and dyspnoea. This study aims to assess the translation of in vitro ENT1 inhibition to the clinical incidence of bronchospasm and dyspnoea in respiratory disease, cardiovascular disease and healthy volunteer populations. Four marketed drugs with ENT1 activity were assessed; dipyridamole, ticagrelor, draflazine, cilostazol. For each patient population, the relationship between in vitro ENT1 [{sup 3}H]-NBTI binding affinity (K{sub i}) and [{sup 3}H]-adenosine uptake (IC{sub 50}) to the incidence of: (1) bronchospasm/severe dyspnoea; (2) tolerated dyspnoea and; (3) no adverse effects, was evaluated. A high degree of ENT1 inhibition (≥ 13.3x K{sub i}, ≥ 4x IC{sub 50}) associated with increased incidence of bronchospasm/severe dyspnoea for patients with respiratory disease only, whereas a lower degree of ENT1 inhibition (≥ 0.1x K{sub i}, ≥ 0.05x IC{sub 50}) associated with a tolerable level of dyspnoea in both respiratory and cardiovascular disease patients. ENT1 inhibition had no effect in healthy volunteers. Furthermore, physicochemical properties correlative with ENT1 binding were assessed using a set of 1625 diverse molecules. Binding to ENT1 was relatively promiscuous (22% compounds K{sub i} < 1 μM) especially for neutral or basic molecules, and greater incidence tracked with higher lipophilicity (clogP > 5). This study rationalises inclusion of an assessment of ENT1 activity during early safety profiling for programs targeting respiratory disorders. - Highlights: • ENT1 inhibition causes bronchospasm and severe dyspnoea in respiratory

Quantitation of myocardial blood flow and myocardial flow reserve with {sup 99m}Tc-sestamibi dynamic SPECT/CT to enhance detection of coronary artery disease

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Hsu, Bailing [University of Missouri-Columbia, Nuclear Science and Engineering Institute, Columbia, MO (United States); Chen, Fu-Chung; Chen, Chien-Cheng [Show Chwan Memorial Hospital, Section of Cardiology, Department of Internal Medicine, Changhua (China); Wu, Tao-Cheng [Taipei Veterans General Hospital, Section of Cardiology, Department of Internal Medicine, Taipei (China); Huang, Wen-Sheng [Changhua Christian Hospital, Department of Medical Research and Department of Nuclear Medicine, Changhua (China); Hou, Po-Nien [Chang Bing Show Chwan Memorial Hospital, Department of Nuclear Medicine, Lukong Town, Changhua Shien (China); Hung, Guang-Uei [Chang Bing Show Chwan Memorial Hospital, Department of Nuclear Medicine, Lukong Town, Changhua Shien (China); Central Taiwan University of Science and Technology, Department of Medical Imaging and Radiological Science, Taichung (China); China Medical University, Department of Biomedical Imaging and Radiological Science, Taichung (China)

2014-12-15

Conventional dual-head single photon emission computed tomography (SPECT)/CT systems capable of fast dynamic SPECT (DySPECT) imaging have a potential for flow quantitation. This study introduced a new method to quantify myocardial blood flow (MBF) and myocardial flow reserve (MFR) with DySPECT scan and evaluated the diagnostic performance of detecting coronary artery disease (CAD) compared with perfusion using invasive coronary angiography (CAG) as the reference standard. This study included 21 patients with suspected or known CAD who had received DySPECT, ECG-gated SPECT (GSPECT), and CAG (13 with ≥50 % stenosis in any vessel; non-CAD group: 8 with patent arteries or <50 % stenosis). DySPECT and GSPECT scans were performed on a widely used dual-head SPECT/CT scanner. The DySPECT imaging protocol utilized 12-min multiple back-and-forth gantry rotations during injections of {sup 99m}Tc-sestamibi (MIBI) tracer at rest or dipyridamole-stress stages. DySPECT images were reconstructed with full physical corrections and converted to the physical unit of becquerels per milliliter. Stress MBF (SMBF), rest MBF (RMBF), and MFR were quantified by a one-tissue compartment flow model using time-activity curves derived from DySPECT images. Perfusion images were processed for GSPECT scan and interpreted to obtain summed stress score (SSS) and summed difference score (SDS). Receiver-operating characteristic (ROC) analyses were conducted to evaluate the diagnostic performance of flow and perfusion. Using the criteria of ≥50 % stenosis as positive CAD, areas under the ROC curve (AUCs) of flow assessment were overall significantly greater than those of perfusion. For patient-based analysis, AUCs for MFR, SMBF, SSS, and SDS were 0.91 ± 0.07, 0.86 ± 0.09, 0.64 ± 0.12, and 0.59 ± 0.13. For vessel-based analysis, AUCs for MFR, SMBF, SSS, and SDS were 0.81 ± 0.05, 0.76 ± 0.06, 0.62 ± 0.07, and 0.56 ± 0.08, respectively. The preliminary data suggest that MBF quantitation with a

Nuclear cardiology in Iran in 2002

International Nuclear Information System (INIS)

Zakavi, S. R.

2004-01-01

Aim: few nuclear cardiology surveys, were published in the literature, mostly from developed countries. the aim of this study is to perform a nuclear cardiology survey in iran. This may lead to better decision making and programming. Methods and materials: a questionnaire was sent by mail or e- mail to all nuclear medicine centers in iran asking for details of nuclear cardiology practice in year 2002. Also ownership of the center were studied using telephone interviews. Results: from 79 nuclear medicine centers in Iran, 55 centers (69.6%) filled the questionnaire including 28 centers in Tehran and 27 centers in other cities. Among them, 27 centers were private clinics. There was 69 gamma cameras in these centers, 62.3 % with SPECT capabilities. it is estimated that we may have 100 gamma cameras in Iran. About 85.5 % of centers perform cardiac studies routinely. Tc-99m-MIBI is used in more than 85.7% of the studies and some centers do not use Tl-201. Pharmacological stress with infusion of Dipyridamole is used in 56.7% of the studies and treadmill is the main type of physical exercise (40.2%). SPECT technique was used in 93% of studies including 2.5% of gated SPECT. About 64.3% of centers used two day protocol for imaging.Our study showed that about 65594 cardiac studies were done in Iran each year with myocardial perfusion scan accounting for about 99.2% of the studies. Considering population of the country(about 65 millions) nuclear cardiology activity will be about 1.01 study/1000/year. For viability assessment, Tl-201 with rest redistribution technique is used in 10.7 % of cases while re-injection is used in 29.8% of cases and TNG augmented Tc-99m-MIBI injection at rest in 59.5%. Discussion: Activity of nuclear cardiology is about 15 studies/1000 population/year is USA and 2.2 studies/1000/year in Europe. Although it is not uniformly practiced in different countries of Europe, however the numbers indicate that nuclear cardiology is under utilized in Iran ( less

Assessment of the effect of revascularization early after CABG using ECG-gated perfusion single-photon emission tomography

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Kubo, Shigeto; Tadamura, Eiji; Kudoh, Takashi; Inubushi, Masayuki; Konishi, Junji; Ikeda, Tadashi; Koshiji, Takaaki; Nishimura, Kazunobu; Komeda, Masashi; Tamaki, Nagara

2001-01-01

When an arterial graft is used, reversible perfusion defects on single-photon emission tomography (SPET) perfusion images are occasionally observed early after coronary artery bypass graft surgery (CABG), owing to the restricted flow capacity. The purpose of this study was to determine whether the functional information obtained with electrocardiography (ECG)-gated perfusion SPET could be helpful in evaluating the effect of revascularization early after CABG. Twenty-three patients (18 men and 5 women, mean age 65±9 years) underwent stress/re-injection thallium-201 ECG-gated SPET before and 4 weeks after CABG (13 with exercise and 10 with dipyridamole). Patency of all grafts was confirmed by coronary angiography 1 month after CABG. Cardiac functional data including the left ventricular ejection fraction (LVEF) and the transient ischaemic dilatation (TID) ratio were analysed using a commercially available automated program. The conventional stress and re-injection tomograms were interpreted by means of a five-point scoring system in a nine-segment model. Stress-induced reversible 201 Tl perfusion defects were present in 64% of the myocardial segments bypassed by patent arterial grafts, in contrast to 42% of the myocardial segments bypassed by patent venous grafts (χ 2 =7.8, P=0.005). Of the 23 patients, 12 showed improvement in summed ischaemic scores (group 1), while 11 had no change or deterioration (group 2), although all grafts were patent on postoperative catheterization. The TID ratio improved in both group 1 and group 2 before and after CABG (1.14±0.13 vs 0.99±0.07, P=0.001 and 1.09±0.07 vs 0.94±0.05, P=0.002, respectively). However, LVEF did not significantly improve in group 1 or group 2 after CABG (42.5%±9.9% vs 47.5%±11.8%, and 52.1%±7.5% vs 53.1%±5.9%, respectively). Perfusion imaging or LVEF assessment is of limited value early after CABG. The TID ratio obtained with ECG-gated perfusion SPET may be a useful marker to evaluate the effect of

Antithrombotic Utilization Trends after Noncardioembolic Ischemic Stroke or TIA in the Setting of Large Antithrombotic Trials (2002–2009)

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Khan, Amir S.; Qureshi, Adnan I.

2015-01-01

Background and Purpose Several large trials published over the last decade have significantly altered recommended guidelines for therapy following a noncardioembolic ischemic stroke or transient ischemic attack (TIA). The impact of these studies on patient usage of alternative antithrombotic agents has hitherto not been evaluated. We examined the usage of these agents in the United States over the last decade, with regard to the publication of the Management of Atherothrombosis with Clopidogrel in High-Risk Patients (MATCH), European/Australasian Stroke Prevention in Reversible Ischaemia Trial (ESPRIT), and Prevention Regimen for Effectively Avoiding Second Strokes (PRoFESS) clinical trials, in order to test the hypothesis that resulting recommendations are reflected in usage trends. Methods Antithrombotic utilization was prospectively collected as part of the National Ambulatory Medical Care Survey (NAMCS) on a total of 53,608,351 patients in the United States between 2002 and 2009. Patients with a history of ischemic stroke or TIA were included. Patients were excluded if there was a prior history of subarachnoid or intracerebral hemorrhage, or if other indications for antithrombotic treatment were present, including deep venous thrombosis, pulmonary embolism, atrial fibrillation or flutter, mechanical cardiac valve replacement, congestive heart failure, coronary artery disease, peripheral arterial disease, and rheumatoid arthritis. Annual utilization of the following antithrombotic strategies was compared in 53,608,351 patients: 1) aspirin monotherapy, 2) clopidogrel monotherapy, 3) combined clopidogrel and aspirin, 4) combined extended-release dipyridamole (ERDP) and aspirin, and 5) warfarin. Annual utilization was compared before and after publication of MATCH, ESPRIT, and PRoFESS in 2004, 2006, and 2008, respectively. Trend analysis was performed with the Mantel–Haenszel test for trends. Sensitivity analysis of demographic and clinical characteristics

[Impact on the gait time cycle of ischemic stroke in the treatment with yin-yang respiratory reinforcing and reducing needling technique].

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Li, Qi; Tian, Fu-Ling; Liu, Guo-Rong; Zheng, De-Song; Chen, Jin-Ming; Ma, Shu-Riang; Cui, Jian-Mei; Wang, Hong-Bin; Li, Xue-Qing

2014-03-01

To compare the difference in the efficacy on gait time cycle of ischemic stroke between yin-yang respiratory reinforcing and reducing needling technique (yin-yang needling) and the conventional acupuncture. Sixty cases of ischemic stroke were randomized into a conventional acupuncture group and a yin-yang needling group, 30 cases in each one. The basic treatment (the control of blood pressure, blood sugar and blood lipid, the intravenous drops of ginkgo leaf extract and dipyridamole injection and vinpocetine injection) were applied in the two groups. Additionally, in the conventional acupuncture group, the acupoints of the Stomach Meridian of Foot-Yangming [Biguan (ST 31), Liangqiu (ST 34), Zusanli (ST 36), Shangjuxu (ST 37), Xiajuxu (ST 39), etc.] were selected and stimulated with the even needling technique. In the yin-yang needling group, the acupoints of yin meridians such as Zuwuli (LR 10), Xuehai (SP 10), Yinlingquan (SP 9) and Sanyinjiao (SP 6), etc. and the acupoints of yang meridians such as Biguan (ST 31), Liangqiu (ST 34) and Yanglingquan (GB 34), etc. were selected. The reducing manipulation of respiratory reinforcing and reducing technique was applied to the acupoints of yin meridians and the reinforcing manipulation was applied to the acupoints of yang meridians. The kinematics time parameters were determined and compared before and 4 weeks after treatment. After treatment, the differences in the gait cycle, the phase time of standing (%), the phase time of single support (%), the phase time of unilateral sway (%) on the affected (healthy) foot and phase time of double support (%) were significant as compared with those before treatment in the patients of the two groups (all P yin-yang needling group were improved much obviously after treatment as compared with those in the conventional acupuncture group. The differences in support phase time (%), single support phase time (%) and sway phase time (%) were significant between the affected limb and

Understanding the generation and maintenance of supersaturation during the dissolution of amorphous solid dispersions using modulated DSC and 1H NMR.

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Baghel, Shrawan; Cathcart, Helen; O'Reilly, Niall J

2018-01-30

In this study, the dissolution behaviour of dipyridamole (DPM) and cinnarizine (CNZ) spray-dried amorphous solid dispersions (ASDs) using polyvinyl pyrrolidone (PVP) and polyacrylic acid (PAA) as a carrier matrix were evaluated and compared. The drug concentrations achieved from the dissolution of PVP and PAA solid dispersions were significantly greater than the equilibrium solubility of crystalline DPM and CNZ in phosphate buffer pH 6.8 (PBS 6.8). The maximum drug concentration achieved by dissolution of PVP and PAA solid dispersions did not exceed the theoretically calculated apparent solubility of amorphous DPM and CNZ. However, the degree of supersaturation of DPM and CNZ increased considerably as the polymer weight fraction within the solid dispersion increased. In addition, the supersaturation profile of DPM and CNZ were studied in the presence and absence of the polymers. PAA was found to maintain a higher level of supersaturation compared to PVP. The enhanced drug solution concentration following dissolution of ASDs can be attributed to the reduced crystal growth rates of DPM and CNZ at an equivalent supersaturation. We have also shown that, for drugs having high crystallization tendency and weak drug-polymer interaction, the feasible way to increase dissolution might be increase the polymer weight fraction in the ASD. Solution 1 H NMR spectra were used to understand dissolution mechanism and to identify drug-polymer interaction. The change in electron densities of proton attached to different groups in DPM and CNZ suggested drug-polymer interaction in solution. The relative intensities of peak shift and nature of interaction between drug and polymer in different systems are different. These different effects suggest that DPM and CNZ interacts in a different way with PVP and PAA in solution which goes some way towards explaining the different polymeric effect, particularly in terms of inhibition of drug recrystallization and dissolution of DPM and CNZ ASDs

Reduced myocardial perfusion reserve in myocardium having coronary artery aneurysm of Kawasaki disease

International Nuclear Information System (INIS)

Yoon, S. N.; Lee, D. S.; Choi, J. Y.; Kil, H. R.; Jeong, Z. K.; Lee, M. C.; Ko, C. S.

1997-01-01

Kawasaki disease is a systemic vasculitis involving the coronary arteries at early childhood and cause coronary artery aneurysms and thrombotic occlusions. These coronary artery aneurysms were usually transformed later into stenotic or obstructive lesions, however, the majority of these aneurysms, even the giant ones, are known to be associated with normal epicardial coronary flow. Flow reserve is difficult to assess in aneurysmal arteries with echo or angiography. We performed this study to question if there are abnormalities in flow reserve in myocardial tissue with normal epicardial arterial flow on angiography in patients with Kawasaki disease, dipyridamole stress and rest Tc-99m-sestamibi SPECT were performed in 37 patients (28 boys, 9 girls, mean age 6.6 years). We compared SPECT findings with coronary angiography (CAG) findings in 21 patients who did both studies after finding abnormality on echocardiaography. On CAG, aneurysms were found in 26 arteries of 16 patients, i.e., 10 left main arteries, 6 left anterior descending arteries (LAD), 2 left circumflex arteries (LCX), and 8 right coronary arteries (RCA). Localized and segmental stenotic lesions were found in 11 arteries in 9 patients (LAD: 4, LCX: 1, RCA: 6). Eight of the 10 patients with aneurysms had no obvious stenosis. On stress-rest SPECT, 16(43%) out of 37 patients showed normal perfusion and the other 21(57%) showed reversible or persistent decrease. Among 11 stenotic artery territories, 3(27%) showed persistent and/or reversible perfusion defects. The other 8 were normal. Among 26 aneurysmal artery territories, 12 artery territories showe perfusion decrease. Three of the 5 patients with normal CAG showed persistent and/or transient perfusion defects. Among 14 artery territories with perfusion decrease in the 16 patients, 3(21%) could be localized to vascular territory having stenosis of supplying coronary arteries, 12(86%) were related to the coronary artery aneurysms. Two were not related to

Extracorporeal Shock Wave Therapy for Coronary Artery Disease: Relationship of Symptom Amelioration and Ischemia Improvement

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Youko Takakuwa

2018-01-01

Full Text Available Objective(s: The current management of coronary artery disease (CAD relies on three major therapeutic options, namely medication, percutaneous coronary intervention (PCI, and coronary artery bypass grafting (CABG. However, severe CAD that is not indicated for PCI or CABG still bears a poor prognosis due to the lack of effective treatments. In 2006, extracorporeal cardiac shock wave (SW therapy reported on human for the first time. This treatment resulted in better myocardial perfusion as evaluated by dipyridamole stress thallium scintigraphy, angina symptoms, and exercise tolerance. The aim of the present study was to investigate myocardial perfusion images and evaluate the relationship between the ischemia improvement and symptom amelioration by SW therapy. Methods: We treated ten patients (i.e., nine males and one female with cardiac SW therapy who had CAD but not indicated for PCI or CABG and aged 63–89 years old. After the SW therapy, all patients were followed up for three months to evaluate any amelioration of the myocardial ischemia based on symptoms, adenosine stress thallium scintigraphy, transthoracic echocardiography, and blood biochemical examinations. Results: The changes in various parameters were evaluated before and after cardiac SW therapy. The cardiac SW therapy resulted in a significant improvement in the symptoms as evaluated by the Canadian Cardiovascular Society [CCS] class score (P=0.016 and a tendency to improve in summed stress score (SSS (P=0.068. However, no significant improvement was observed in the summed rest score (SRS, summed difference score (SDS, left ventricular wall motion score index (LVWMSI, N-terminal pro-brain natriuretic, and troponin I. The difference of CCS class score (ΔCCS was significantly correlated with those of SSS (ΔSSS and SDS (ΔSDS (r=0.69, P=0.028 and r=0.70, P=0.025, respectively. There was no significant correlation between ΔCCS and other parameters. Furthermore, no significant

Recruitment of aged donor heart with pharmacological stress echo. A case report

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Bombardini Tonino

2006-01-01

Full Text Available Abstract Background The heart transplant is a treatment of the heart failure, which is not responding to medications, and its efficiency is already proved: unfortunately, organ donation is a limiting step of this life-saving procedure. To counteract heart donor shortage, we should screen aged potential donor hearts for initial cardiomyopathy and functionally significant coronary artery disease. Donors with a history of cardiac disease are generally excluded. Coronary angiography is recommended for most male donors older than 45 years and female donors older than 50 years to evaluate coronary artery stenoses. A simpler way to screen aged potential donor hearts for initial cardiomyopathy and functionally significant coronary artery disease should be stress echocardiography. Case report A marginal donor (A 57 year old woman meeting legal requirements for brain death underwent a transesophageal (TE Dipyridamole stress echo (6 minutes accelerated protocol to rule out moderate or severe heart and coronary artery disease. Wall motion was normal at baseline and at peak stress (WMSI = 1 at baseline and peak stress, without signs of stress inducible ischemia. The pressure/volume ratio was 9.6 mmHg/ml/m2 at baseline, increasing to 14 mmHg/ml/m2 at peak stress, demonstrating absence of latent myocardial dysfunction. The marginal donor heart was transplanted to a recipient "marginal" for co-morbidity ( a 63 year old man with multiple myeloma and cardiac amyloidosis , chronic severe heart failure, NYHA class IV. Postoperative treatment and early immunosuppressant regimen were performed according to standard protocols. The transplanted heart was assessed normal for dimensions and ventricular function at transthoracic (TT echocardiography on post-transplant day 7. Coronary artery disease was ruled out at coronary angiography one month after transplant; left ventriculography showed normal global and segmental LV function of the transplanted heart. Conclusion For

Theoretical and experimental investigation of drug-polymer interaction and miscibility and its impact on drug supersaturation in aqueous medium.

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Baghel, Shrawan; Cathcart, Helen; O'Reilly, Niall J

2016-10-01

Amorphous solid dispersions (ASDs) have the potential to offer higher apparent solubility and bioavailability of BCS class II drugs. Knowledge of the solid state drug-polymer solubility/miscibility and their mutual interaction are fundamental requirements for the effective design and development of such systems. To this end, we have carried out a comprehensive investigation of various ASD systems of dipyridamole and cinnarizine in polyvinylpyrrolidone (PVP) and polyacrylic acid (PAA) at different drug loadings. Theoretical and experimental examinations (by implementing binary and ternary Flory-Huggins (F-H) theory) related to drug-polymer interaction/miscibility including solubility parameter approach, melting point depression method, phase diagram, drug-polymer interaction in the presence of moisture and the effect of drug loading on interaction parameter were performed. The information obtained from this study was used to predict the stability of ASDs at different drug loadings and under different thermal and moisture conditions. Thermal and moisture sorption analysis not only provided the composition-dependent interaction parameter but also predicted the composition dependent miscibility. DPM-PVP, DPM-PAA and CNZ-PAA systems have shown molecular level mixing over the complete range of drug loading. For CNZ-PVP, the presence of a single Tg at lower drug loadings (10, 20 and 35%w/w) indicates the formation of solid solution. However, drug recrystallization was observed for samples with higher drug weight fractions (50 and 65%w/w). Finally, the role of polymer in maintaining drug supersaturation has also been explored. It has been found that drug-polymer combinations capable of hydrogen-bonding in the solution state (DPM-PVP, DPM-PAA and CNZ-PAA) are more effective in preventing drug crystallization compared to the drug-polymer systems without such interaction (CNZ-PVP). The DPM-PAA system outperformed all other ASDs in various stability conditions (dry-state, in

Regadenoson in the detection of coronary artery disease

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Christiane Buhr

2008-04-01

Full Text Available Christiane Buhr1, Mario Gössl2, Raimund Erbel1, Holger Eggebrecht11Department of Cardiology, West-German Heart Center Essen, University of Duisburg-Essen, Essen, Germany; 2Cardiovascular Diseases, Mayo Clinic College of Medicine, Rochester, MN 55905, USAAbstract: Myocardial perfusion studies use either physical exercise or pharmacologic vasodilator stress to induce maximum myocardial hyperemia. Adenosine and dipyridamole are the most commonly used agents to induce coronary arterial vasodilation for myocardial perfusion imaging. Both cause frequent undesirable side-effects. Because of its ultrashort half-life, adenosine must be administered by constant intravenous infusion during the examination. A key feature of an ideal A2A agonist for myocardial perfusion imaging studies would be an optimal level and duration of hyperemic response. Drugs with a longer half-time and more selective A2A adenosine receptor agonism, such as regadenoson, should theoretically result in a similar degree of coronary vasodilation with fewer or less severe side-effects than non-selective, ultrashort-lasting adenosine receptor stimulation. The available preclinical and clinical data suggest that regadenoson is a highly subtype-selective, potent, low-affinity A2A adenosine receptor agonist that holds promise for future use as a coronary vasodilator in myocardial perfusion imaging studies. Infusion of regadenoson achieves maximum coronary hyperemia that is equivalent to adenosine. After a single bolus infusion over 10 s, hyperemia is maintained significantly longer (approximately 2–5 min than with adenosine, which should facilitate radionuclide distribution for myocardial perfusion imaging studies. In comparison with the clinically competitive A2A adenosine receptor agonist binodenoson, regadenoson has a several-fold shorter duration of action, although the magnitude of hyperemic response is comparable between the two. The more rapid termination of action of regadenoson

Effects of Insulin Resistance on Myocardial Blood Flow and Arterial Peripheral Circulation in Patients with Polycystic Ovary Syndrome.

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Aldrighi, José M; Tsutsui, Jeane M; Kowastch, Ingrid; Ribeiro, Alessandra L; Scapinelli, Alessandro; Tamanaha, Sonia; Oliveira, Ricardo M; Mathias, Wilson

2015-08-01

Polycystic ovary syndrome (PCOS) is associated with increased risk for cardiovascular disease. We sought to evaluate the effects of insulin resistance (IR) on myocardial microcirculation and peripheral artery function in patients with PCOS. We studied 55 women (28 with PCOS without IR, 18 with PCOS and IR and 11 normal controls) who underwent laboratorial analysis, high-resolution vascular ultrasound and real time myocardial contrast echocardiography (RTMCE). Intima-media thickness (IMT) and brachial artery flow-mediated dilation (FMD) were evaluated by vascular ultrasound. The replenishment velocity (β), plateau of acoustic intensity (A) and myocardial blood flow reserve (MBFR) were determined by quantitative dipyridamole stress RTMCE. β reserve in group PCOS + IR was lower than control (2.34 ± 0.55 vs. 3.60 ± 0.6; P PCOS without IR (2.34 ± 0.55 vs. 3.17 ± 0.65; P PCOS without IR did not differ from those of control (4.59 ± 1.59 vs. 5.30 ± 1.64; P = 0.22) or from patients with PCOS + IR (4.59 ± 1.59 vs. 3.70 ± 1.47; P = 0.07). When comparing with control group, patients with PCOS + IR had lower MBFR (5.30 ± 1.64 vs. 3.70 ± 1.47; P = 0.01). No significant differences were found between control, PCOS without IR and PCOS + IR for FMD (0.18 ± 0.05, 0.15 ± 0.04 and 0.13 ± 0.07; P =NS) or IMT (0.48 ± 0.05, 0.47 ± 0.05 and 0.49 ± 0.07; P = NS). Women with PCOS and IR had depressed β and MBFR as demonstrated by quantitative RTMCE, but no alteration in endothelial dysfunction or IMT. PCOS without IR showed isolated depression in β reserve, probably an earlier marker of myocardial flow abnormality. © 2014, Wiley Periodicals, Inc.

ABC gene-ranking for prediction of drug-induced cholestasis in rats

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Yauheniya Cherkas

drugs that behaved very differently, and were distinct from both non-cholestatic and cholestatic drugs (ketoconazole, dipyridamole, cyproheptadine and aniline, and many postulated human cholestatic drugs that in rat showed no evidence of cholestasis (chlorpromazine, erythromycin, niacin, captopril, dapsone, rifampicin, glibenclamide, simvastatin, furosemide, tamoxifen, and sulfamethoxazole. Most of these latter drugs were noted previously by other groups as showing cholestasis only in humans. The results of this work suggest that the ABC procedure and similar statistical approaches can be instrumental in combining data to compare toxicants across toxicogenomics databases, extract similarities among responses and reduce unexplained data varation. Keywords: Cluster analysis, Cholestasis, Gene signature, Microarray, Prediction, Toxicogenomics

Criteria for definition of regional functional improvement on quantitative post-stress gated myocardial SPET after bypass surgery in patients with ischaemic cardiomyopathy

International Nuclear Information System (INIS)

Lee, Dong Soo; Cheon, Gi Jeong; Paeng, Jin Chul; Chung, June-Key; Lee, Myung Chul; Kim, Ki Bong

2002-01-01

Myocardial viability can be defined as functional improvement of dysfunctional myocardium after revascularization. The purpose of this study was to define the optimal criteria for definition of regional functional improvement after coronary artery bypass graft (CABG) surgery on quantitative gated single-photon emission tomography (SPET). Thirty-two patients (26 men, 6 women; age 56±13 years) with coronary artery disease (three-vessel disease, 17; two-vessel disease, 15; previous history of myocardial infarction, 9) and severe left ventricular dysfunction (LVEF≤35%) underwent CABG. Rest thallium-201/dipyridamole stress technetium-99m methoxyisobutylisonitrile gated myocardial SPET was performed before and 3 months after CABG. Global LV functional improvement was defined as either an improvement in LVEF of 10% (n=15) or an improvement in LVEF of 5% combined with a decrease in end-systolic volume of 10 ml (n=2) after CABG on quantitative gated SPET. Postoperative regional wall thickening improvement (ΔRWT), regional wall motion improvement (ΔRWM) and regional resting (ΔRP) and stress perfusion improvement (ΔRstrP) were used to determine global functional improvement by ROC curve analysis, and the optimal criteria for definition of viable regional dysfunctional myocardium were defined on the ROC curves. Correlations were verified by determining the number of improved myocardial regions and LVEF improvement. LVEF was improved from 25%±6% to 34%±11% after CABG. A total of 229 segments were dysfunctional (wall motion ≤2 mm, thickening ≤20%) before CABG. On ROC curve analysis using global functional improvement as an indicator of viability, the areas under the ROC curves (AUCs) of ΔRWT and ΔRWM were 0.717 and 0.620, respectively. The AUC of ΔRWT was significantly larger than that of ΔRWM (P=0.009) and the optimal cut-off value of ΔRWT was 15%. The AUCs of ΔRP and ΔRstrP were not significant. The correlation coefficients between summed ΔRWT and �

Surveillance study for creating the national clinical database relating to ECG-gated myocardial perfusion SPECT of asymptomatic ischemic heart disease in patients with type-2 diabetes mellitus. J-ACCESS 2 study design

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Kusuoka, Hideo; Yamasaki, Yoshimitsu; Izumi, Tohru; Kashiwagi, Atsunori; Kawamori, Ryuzo; Shimamoto, Kazuaki; Yamada, Nobuhiro; Nishimura, Tsunehiko

2008-01-01

Diabetes mellitus is an independent risk factor for acute myocardial infarction. Thus, a surveillance study was conducted as part of studies to create a national database related to electrocardiogram (ECG)-gated myocardial perfusion single-photon emission computed tomography (SPECT) of ischemic heart disease. Single-photon emission computed tomography was conducted in patients with type 2 diabetes mellitus and their prognoses will be followed for 3 years, stratified by patients' clinical background and SPECT findings. A total of 513 patients from 50 institutions were enrolled in this study, 297 of whom were men (age 66.2±0.4 years, mean±standard error of the mean (SEM)) and 261 women (age 67.8±0.5 years). They have a history of retinopathy (25.3%), neuropathy (19.9%), cerebrovascular disorder, chronic obstructive pulmonary disease, and photocoagulation. Major risk factors for present disease were hypertension (82.3%) and hyperlipidemia (79.7%). In 244 patients (129 men and 115 women), body mass index (BMI) was 25 or more. Fifty-two of them (10.1%) underwent coronary angiography; of these, 26 (50.0%) had no coronary artery lesions with 75% or more stenosis, and only 1 (1.9%) had a left main trunk with 50% or more stenosis. An overwhelming majority of patients (94.3%) underwent SPECT imaging by a 1-day stress-followed-by-rest procedure. Stress procedure was exercise in most (70.8%) patients, followed by dipyridamole infusion in 14.6%, adenosine infusion in 6.6%, and adenosine triphosphate infusion in 5.7%. Endpoint of stress examination was most often fatigue in lower limbs (40.7%), followed by completion of pharmacological stress protocol (28.7%), and achievement of target heart rate (26.3%). The largest number of patients (198, 38.6%) received 99m Tc-tetrofosmin at an initial dosage of 200-300 MBq (mean 331±3 MBq) followed by a second dosage of 700-800 MBq (mean 748±8 MBq). Among them, 491 (95.7%) received some kind of therapeutic drug: hypoglycemic drugs were

Myocardial stress perfusion magnetic resonance: initial experience in a pediatric and young adult population using regadenoson

International Nuclear Information System (INIS)

Noel, Cory V.; Krishnamurthy, Ramkumar; Krishnamurthy, Rajesh; Moffett, Brady

2017-01-01

Dipyridamole and adenosine are traditional pharmacological stressors for myocardial perfusion. Regadenoson, a selective adenosine A2A agonist, has a lower side effect profile with lower incidence of bronchospasm and bradycardia. There is a growing need for myocardial perfusion assessment within pediatrics. There is no report on the utility of regadenoson as a stress agent in children. To observe the safety and feasibility of regadenoson as a pharmacologic stressor for perfusion cardiac MR in a pilot cohort of pediatric patients weighing more than 40 kg who have congenital heart disease and pediatric acquired heart disease. We reviewed our initial experience with regadenoson stress cardiac MR in 31 pediatric patients 15.8 ± 1.7 years (range 12-22 years) with congenital heart disease and acquired heart disease. Mean patient weight was 60 ± 15 kg (range of 40-93 kg). All patients underwent cardiac MR because of concern for ischemia. The cohort included a heterogeneous group of patients at a pediatric institution with potential risk for ischemia. Subjects' heart rate and blood pressure were monitored and pharmacologic stress was induced by injection of 400 mcg of regadenoson. We evaluated their hemodynamic response and adverse effects using changes in vital signs and onset of symptoms. A pediatric cardiologist and radiologist qualitatively assessed myocardial perfusion and viability images. One child was unable to complete the stress perfusion portion of the examination, but did complete the remaining portion of the CMR. Resting heart rate was 72 ± 14 beats per minute (bpm) and rose to peak of 124 ± 17 bpm (95 ± 50% increase, P < 0.005) with regadenoson. Image quality was considered good or diagnostic in all cases. Three patients had irreversible perfusion defects. Four patients had reversible perfusion defects. Nine of the patients underwent cardiac catheterization with angiography and the findings showed excellent agreement. Regadenoson might be a safe and

RApid Primary care Initiation of Drug treatment for Transient Ischaemic Attack (RAPID−TIA): study protocol for a pilot randomised controlled trial

Science.gov (United States)

2013-01-01

Background People who have a transient ischaemic attack (TIA) or minor stroke are at high risk of a recurrent stroke, particularly in the first week after the event. Early initiation of secondary prevention drugs is associated with an 80% reduction in risk of stroke recurrence. This raises the question as to whether these drugs should be given before being seen by a specialist – that is, in primary care or in the emergency department. The aims of the RAPID-TIA pilot trial are to determine the feasibility of a randomised controlled trial, to analyse cost effectiveness and to ask: Should general practitioners and emergency doctors (primary care physicians) initiate secondary preventative measures in addition to aspirin in people they see with suspected TIA or minor stroke at the time of referral to a specialist? Methods/Design This is a pilot randomised controlled trial with a sub-study of accuracy of primary care physician diagnosis of TIA. In the pilot trial, we aim to recruit 100 patients from 30 general practices (including out-of-hours general practice centres) and 1 emergency department whom the primary care physician diagnoses with TIA or minor stroke and randomly assign them to usual care (that is, initiation of aspirin and referral to a TIA clinic) or usual care plus additional early initiation of secondary prevention drugs (a blood-pressure lowering protocol, simvastatin 40 mg and dipyridamole 200 mg m/r bd). The primary outcome of the main study will be the number of strokes at 90 days. The diagnostic accuracy sub-study will include these 100 patients and an additional 70 patients in whom the primary care physician thinks the diagnosis of TIA is possible, rather than probable. For the pilot trial, we will report recruitment rate, follow-up rate, a preliminary estimate of the primary event rate and occurrence of any adverse events. For the diagnostic study, we will calculate sensitivity and specificity of primary care physician diagnosis using the final

RApid Primary care Initiation of Drug treatment for Transient Ischaemic Attack (RAPID-TIA): study protocol for a pilot randomised controlled trial.

Science.gov (United States)

Edwards, Duncan; Fletcher, Kate; Deller, Rachel; McManus, Richard; Lasserson, Daniel; Giles, Matthew; Sims, Don; Norrie, John; McGuire, Graham; Cohn, Simon; Whittle, Fiona; Hobbs, Vikki; Weir, Christopher; Mant, Jonathan

2013-07-02

People who have a transient ischaemic attack (TIA) or minor stroke are at high risk of a recurrent stroke, particularly in the first week after the event. Early initiation of secondary prevention drugs is associated with an 80% reduction in risk of stroke recurrence. This raises the question as to whether these drugs should be given before being seen by a specialist--that is, in primary care or in the emergency department. The aims of the RAPID-TIA pilot trial are to determine the feasibility of a randomised controlled trial, to analyse cost effectiveness and to ask: Should general practitioners and emergency doctors (primary care physicians) initiate secondary preventative measures in addition to aspirin in people they see with suspected TIA or minor stroke at the time of referral to a specialist? This is a pilot randomised controlled trial with a sub-study of accuracy of primary care physician diagnosis of TIA. In the pilot trial, we aim to recruit 100 patients from 30 general practices (including out-of-hours general practice centres) and 1 emergency department whom the primary care physician diagnoses with TIA or minor stroke and randomly assign them to usual care (that is, initiation of aspirin and referral to a TIA clinic) or usual care plus additional early initiation of secondary prevention drugs (a blood-pressure lowering protocol, simvastatin 40 mg and dipyridamole 200 mg m/r bd). The primary outcome of the main study will be the number of strokes at 90 days. The diagnostic accuracy sub-study will include these 100 patients and an additional 70 patients in whom the primary care physician thinks the diagnosis of TIA is possible, rather than probable. For the pilot trial, we will report recruitment rate, follow-up rate, a preliminary estimate of the primary event rate and occurrence of any adverse events. For the diagnostic study, we will calculate sensitivity and specificity of primary care physician diagnosis using the final TIA clinic diagnosis as the

Long-Term Outcomes of Patent Foramen Ovale Closure or Medical Therapy after Stroke.

Science.gov (United States)

Saver, Jeffrey L; Carroll, John D; Thaler, David E; Smalling, Richard W; MacDonald, Lee A; Marks, David S; Tirschwell, David L

2017-09-14

Whether closure of a patent foramen ovale reduces the risk of recurrence of ischemic stroke in patients who have had a cryptogenic ischemic stroke is unknown. In a multicenter, randomized, open-label trial, with blinded adjudication of end-point events, we randomly assigned patients 18 to 60 years of age who had a patent foramen ovale (PFO) and had had a cryptogenic ischemic stroke to undergo closure of the PFO (PFO closure group) or to receive medical therapy alone (aspirin, warfarin, clopidogrel, or aspirin combined with extended-release dipyridamole; medical-therapy group). The primary efficacy end point was a composite of recurrent nonfatal ischemic stroke, fatal ischemic stroke, or early death after randomization. The results of the analysis of the primary outcome from the original trial period have been reported previously; the current analysis of data from the extended follow-up period was considered to be exploratory. We enrolled 980 patients (mean age, 45.9 years) at 69 sites. Patients were followed for a median of 5.9 years. Treatment exposure in the two groups was unequal (3141 patient-years in the PFO closure group vs. 2669 patient-years in the medical-therapy group), owing to a higher dropout rate in the medical-therapy group. In the intention-to-treat population, recurrent ischemic stroke occurred in 18 patients in the PFO closure group and in 28 patients in the medical-therapy group, resulting in rates of 0.58 events per 100 patient-years and 1.07 events per 100 patient-years, respectively (hazard ratio with PFO closure vs. medical therapy, 0.55; 95% confidence interval [CI], 0.31 to 0.999; P=0.046 by the log-rank test). Recurrent ischemic stroke of undetermined cause occurred in 10 patients in the PFO closure group and in 23 patients in the medical-therapy group (hazard ratio, 0.38; 95% CI, 0.18 to 0.79; P=0.007). Venous thromboembolism (which comprised events of pulmonary embolism and deep-vein thrombosis) was more common in the PFO closure group

Clinical value and severity of myocardial perfusion defects in asymptomatic diabetic patients with negative or weakly positive exercise treadmill test

International Nuclear Information System (INIS)

Zakavi, Seyed Rasoul; Taherpour, Mehdi; Moossavi, Zohreh; Sadeghi, Ramin; Kakhki, Vahidreza Dabbagh; Rokni, Haleh

2013-01-01

Although coronary artery disease (CAD) is the leading cause of death in type 2 diabetic patients, it is frequently asymptomatic. Myocardial perfusion imaging (MPI) is reported to show ischemia in a significant number of asymptomatic diabetic patients. We studied the prevalence and severity of myocardial perfusion defects in asymptomatic diabetic patients and its clinical impact. One hundred thirty consecutive asymptomatic patients, aged 35-65 years with type 2 diabetes mellitus and with no history of CAD and no cardiac symptoms were recruited in the study. Echocardiography, electrocardiography (ECG), routine laboratory tests and exercise treadmill test (ETT) were performed and patients with weakly positive or negative ETT underwent Dipyridamole MPI. Patients with positive ETT were referred to coronary angiography. Patients were followed for at least 17 months (mean 21.7 months) and any cardiac event was recorded. We studied 81 female and 49 male patients with mean age of 51.8 years. Negative, weakly positive and positive ETT result was noted in 74.3%, 15% and 10.7% respectively. 75% of patients with positive ETT had coronary artery disease in angiography. Gated myocardial perfusion SPECT was done in 106 patients. MPI showed reversible defect in 26.9% of the patients with a mean summed stress score of 3.3±1.8. Follow up completed in 112 patients and only one patient with abnormal MPI underwent coronary angiography followed by PTCA. No cardiac death, MI, UA or hospital admission occurred among our patients during follow up (17-26 months). Mean stress end diastolic volume (EDV) was significantly higher in patients with reversible defect compared to patients without reversible defect based on MPI findings (62.0±31.6 Vs 48.5±18.4 ml, P=0.04). Blood glucose and HbA1c were significantly higher in patients with ischemia compared to patients without ischemia (P<0.05). Meanwhile the ratio of TG to HDL was 6.06±3.2 in ischemic patients compared to 4.8±2.3 in normal

Feasibility and diagnostic accuracy of Ecg-gated SPECT myocardial perfusion imaging by a two-hour protocol: The Myofast study;Faisabilite et precision diagnostique d'un protocole de scintigraphie myocardique synchronisee a l'ECG en deux heures: l'etude Myofast

Energy Technology Data Exchange (ETDEWEB)

Dunet, V.; Costo, S.; Sabatier, R.; Grollier, G.; Bouvard, G.; Agostini, D. [CHU Cote-de-Nacre, Service de medecine nucleaire, 14 - Caen (France)

2010-04-15

Aim of the study: To assess the feasibility of early stress and rest myocardial perfusion and function study using a fast {sup 99m}Tc-tetrofosmin gated-SPECT protocol in patients with known coronary artery disease. Materials and methods: Forty-three patients (pts) (37 M, 6 F, mean age 63.8 +- 9.8 years) underwent a {sup 99m}Tc-Tetrofosmin gated-SPECT (Axis Picker-Philips) myocardial study and a coronary angiography (C.A.) within 3 months. Images were acquired (LEHR, eight bins, 40 sec per image) after injection of {sup 99m}Tc-tetrofosmin (200 to 380 MBq) early (15 min) post-stress (36 dipyridamole, two dobutamine and five ergo-metric stress), and at rest after {sup 99m}Tc-tetrofosmin reinjection (600 to 1150 MBq), in a total time not exceeding 2 hours. Processing was performed with Q.G.S. software using the 17-segment model. Pathological study was defined as a summed difference score (SDS) greater than or equal to 4 4, a fixed defect with summed rest score greater than or equal to 4 and/or L.V. dysfunction defined as myocardial stunning (variation between stress and rest L.V.E.F. greater than or equal to 4 5%), stress L.V.E.F. less than or equal to 45% or rest L.V.E.F. less than or equal to 40%. Results were compared with C.A., and stenosis greater than or equal to 4 50% was considered as significant. Results: For 100% the quality of SPECT imaging was good or excellent. For six patients gating was impossible because of arrhythmia. The overall sensitivity, specificity and accuracy were 95%, 50%, and 91%, respectively. The concordance between gated SPECT and C.A. was moderate (kappa = 0.45, S.E. = 0.15). Interestingly, early-gated acquisition permitted to underline left ventricular dysfunction in 11 cases (30%), of whom eight had poly vascular disease. Stunning was detected in six of 37 cases (16%), of whom six had poly vascular disease. Conclusion: A one-day two-hour {sup 99m}Tc-tetrofosmin gated-SPECT protocol to assess left ventricular perfusion and function is

Myocardial stress perfusion magnetic resonance: initial experience in a pediatric and young adult population using regadenoson

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Noel, Cory V. [Baylor College of Medicine, Department of Pediatric Cardiology, Houston, TX (United States); Texas Children' s Hospital, Department of Pediatric Cardiology, Houston, TX (United States); Krishnamurthy, Ramkumar; Krishnamurthy, Rajesh [Texas Children' s Hospital, Department of Radiology, Houston, TX (United States); Moffett, Brady [Texas Children' s Hospital, Department of Pharmacology, Houston, TX (United States)

2017-03-15

Dipyridamole and adenosine are traditional pharmacological stressors for myocardial perfusion. Regadenoson, a selective adenosine A2A agonist, has a lower side effect profile with lower incidence of bronchospasm and bradycardia. There is a growing need for myocardial perfusion assessment within pediatrics. There is no report on the utility of regadenoson as a stress agent in children. To observe the safety and feasibility of regadenoson as a pharmacologic stressor for perfusion cardiac MR in a pilot cohort of pediatric patients weighing more than 40 kg who have congenital heart disease and pediatric acquired heart disease. We reviewed our initial experience with regadenoson stress cardiac MR in 31 pediatric patients 15.8 ± 1.7 years (range 12-22 years) with congenital heart disease and acquired heart disease. Mean patient weight was 60 ± 15 kg (range of 40-93 kg). All patients underwent cardiac MR because of concern for ischemia. The cohort included a heterogeneous group of patients at a pediatric institution with potential risk for ischemia. Subjects' heart rate and blood pressure were monitored and pharmacologic stress was induced by injection of 400 mcg of regadenoson. We evaluated their hemodynamic response and adverse effects using changes in vital signs and onset of symptoms. A pediatric cardiologist and radiologist qualitatively assessed myocardial perfusion and viability images. One child was unable to complete the stress perfusion portion of the examination, but did complete the remaining portion of the CMR. Resting heart rate was 72 ± 14 beats per minute (bpm) and rose to peak of 124 ± 17 bpm (95 ± 50% increase, P < 0.005) with regadenoson. Image quality was considered good or diagnostic in all cases. Three patients had irreversible perfusion defects. Four patients had reversible perfusion defects. Nine of the patients underwent cardiac catheterization with angiography and the findings showed excellent agreement. Regadenoson might be a safe and

Effects of aspirin plus extended-release dipyridamole versus clopidogrel and telmisartan on disability and cognitive function after recurrent stroke in patients with ischaemic stroke in the Prevention Regimen for Effectively Avoiding Second Strokes (PRoFESS) trial

DEFF Research Database (Denmark)

Diener, Hans-Christoph; Sacco, Ralph L; Yusuf, Salim

2008-01-01

BACKGROUND: The treatment of ischaemic stroke with neuroprotective drugs has been unsuccessful, and whether these compounds can be used to reduce disability after recurrent stroke is unknown. The putative neuroprotective effects of antiplatelet compounds and the angiotensin II receptor antagonist...

Effects of gastric pH on oral drug absorption: In vitro assessment using a dissolution/permeation system reflecting the gastric dissolution process.

Science.gov (United States)

Kataoka, Makoto; Fukahori, Miho; Ikemura, Atsumi; Kubota, Ayaka; Higashino, Haruki; Sakuma, Shinji; Yamashita, Shinji

2016-04-01

The aim of the present study was to evaluate the effects of gastric pH on the oral absorption of poorly water-soluble drugs using an in vitro system. A dissolution/permeation system (D/P system) equipped with a Caco-2 cell monolayer was used as the in vitro system to evaluate oral drug absorption, while a small vessel filled with simulated gastric fluid (SGF) was used to reflect the gastric dissolution phase. After applying drugs in their solid forms to SGF, SGF solution containing a 1/100 clinical dose of each drug was mixed with the apical solution of the D/P system, which was changed to fasted state-simulated intestinal fluid. Dissolved and permeated amounts on applied amount of drugs were then monitored for 2h. Similar experiments were performed using the same drugs, but without the gastric phase. Oral absorption with or without the gastric phase was predicted in humans based on the amount of the drug that permeated in the D/P system, assuming that the system without the gastric phase reflected human absorption with an elevated gastric pH. The dissolved amounts of basic drugs with poor water solubility, namely albendazole, dipyridamole, and ketoconazole, in the apical solution and their permeation across a Caco-2 cell monolayer were significantly enhanced when the gastric dissolution process was reflected due to the physicochemical properties of basic drugs. These amounts resulted in the prediction of higher oral absorption with normal gastric pH than with high gastric pH. On the other hand, when diclofenac sodium, the salt form of an acidic drug, was applied to the D/P system with the gastric phase, its dissolved and permeated amounts were significantly lower than those without the gastric phase. However, the oral absorption of diclofenac was predicted to be complete (96-98%) irrespective of gastric pH because the permeated amounts of diclofenac under both conditions were sufficiently high to achieve complete absorption. These estimations of the effects of

Comparison of Hemodynamic Effects and Negative Predictive Value of Normal Adenosine Gated Myocardial Perfusion Scan With or Without Caffeine Abstinence

International Nuclear Information System (INIS)

Zaman, Maseeh uz; Fatima, Nosheen; Zaman, Areeba; Zaman, Unaiza; Tahseen, Rabia

2016-01-01

For vasodilator stress, myocardial perfusion imaging (MPI) with at least 12-h caffeine abstinence is recommended, as it attenuates cardiovascular hyperemic response of adenosine and dipyridamole. However, many published conflicting results have shown no significant effect upon perfusion abnormalities in MPI performed without caffeine abstinence. The aim of this study was to compare the hemodynamic changes and negative predictive value (NPV) of normal MPIs with adenosine stress performed with or without caffeine abstinence. This was a prospective study that accrued 50 patients from May 2013 till September 2013 and followed till November 2014. These patients had a normal adenosine-gated MPI (GMPI) with technetium-99m methoxy isobutyl isonitrile ( 99m Tc-MIBI) after 12-h caffeine abstinence (no-caffeine). Next day, all patients had a repeat adenosine stress within 60 min after ingestion of a cup of coffee (about 80 mg of caffeine) followed by no MPI in 30 patients due to concern about radiation dose (prior-caffeine adenosine—no MPI; group A). Twenty patients opted for a repeat MPI (prior-caffeine adenosine—MPI; group B). Adenosine-induced hemodynamic response and NPV of the normal MPI with no-caffeine and prior-caffeine protocols were compared. The mean age of the study cohort was 57 ± 9 years with a male-to-female ratio of 76:24% and mean body mass index (BMI) of 26.915 ± 4.121 kg/m 2 . Prevalence of hypertension, diabetes, dyslipidemia, and positive family history were 76%, 20%, 22%, and 17%, respectively. Comparison of group A with group B revealed no significant difference in demographic parameters, hemodynamic or electrocardiography (ECG) parameters, or left ventricular (LV) function parameters during adenosine intervention with prior-caffeine and no-caffeine protocols. During the follow-up, no fatal myocardial infarction (MI) was reported but 6 nonfatal MIs were reported based upon the history of short hospitalization for chest pain but without biochemical

Does current oral antiplatelet agent or subtherapeutic anticoagulation use have an effect on tissue-plasminogen-activator-mediated recanalization rate in patients with acute ischemic stroke?

Science.gov (United States)

Ibrahim, Mohamed M; Sebastian, Joseph; Hussain, Muhammad; Al-Hussain, Fawaz; Uchino, Ken; Molina, Carlos; Khan, Khurshid; Demchuk, Andrew M; Alexandrov, Andrei V; Saqqur, Maher

2010-01-01

Our goal is to assess if current antiplatelet (AP) use has an effect on recanalization rate and outcome in acute stroke patients. We conducted a retrospective analysis of acute stroke patients who received intravenous (IV) recombinant tissue plasminogen activator (rt-PA) and had transcranial Doppler examination within 3 h of symptom onset. The TCD findings were interpreted using the Thrombolysis in Brain Ischemia flow grading system as persistent arterial occlusion, reocclusion or complete recanalization. Complete recanalization was defined as established Thrombolysis in Brain Ischemia 4 or 5 within 2 h of IV rt-PA. The patients were divided based on their current use of AP agents. Comparisons were made between the different groups based on recanalziation rate, reocclusion and good long-term outcome (mRS ≤ 2) using χ(2) test. Multiple regression analysis was used to identify AP use as a predictor for recanalization and outcome including symptomatic intracranial hemorrhage after controlling for age, baseline NIHSS score, time to treatment, previous vascular event, hypertension and diabetes mellitus. Two hundred and eighty-four patients were included; 154 (54%) males, 130 (46%) females, with a mean age of 69.5 ± 13 years. The median baseline NIHSS score was 16 ± 5. The median time to TCD examination was 131 ± 38 min from symptom onset. The median time to IV rt-PA was 140 ± 34 min. One hundred eighty patients were not on AP prior to their stroke, 76 were on aspirin, 15 were on clopidogrel, 2 were on aspirin-dipyridamole combination, 2 were on both aspirin and clopidogrel, and 9 patients on subtherapeutic coumadin. In patients who were naïve to AP, 68/178 (38.2%) had complete recanalization, whereas in the AP group, 25/91 (28%) had complete recanalization. Patients on aspirin alone had a lower recanalization rate (16/72) as compared to those not on AP (22 vs. 39%) (p = 0.017), while those on clopidogrel had higher rates of complete recanalization (9/19, 60

Dependency of cardiac rubidium-82 imaging quantitative measures on age, gender, vascular territory, and software in a cardiovascular normal population.

Science.gov (United States)

Sunderland, John J; Pan, Xiao-Bo; Declerck, Jerome; Menda, Yusuf

2015-02-01

Recent technological improvements to PET imaging equipment combined with the availability of software optimized to calculate regional myocardial blood flow (MBF) and myocardial flow reserve (MFR) create a paradigm shifting opportunity to provide new clinically relevant quantitative information to cardiologists. However, clinical interpretation of the MBF and MFR is entirely dependent upon knowledge of MBF and MFR values in normal populations and subpopulations. This work reports Rb-82-based MBF and MFR measurements for a series of 49 verified cardiovascularly normal subjects as a preliminary baseline for future clinical studies. Forty-nine subjects (24F/25M, ages 41-69) with low probability for coronary artery disease and with normal exercise stress test were included. These subjects underwent rest/dipyridamole stress Rb-82 myocardial perfusion imaging using standard clinical techniques (40 mCi injection, 6-minute acquisition) using a Siemens Biograph 40 PET/CT scanner with high count rate detector option. List mode data was rehistogrammed into 26 dynamic frames (12 × 5 seconds, 6 × 10 seconds, 4 × 20 seconds, 4 × 40 seconds). Cardiac images were processed, and MBF and MFR calculated using Siemens syngo MBF, PMOD, and FlowQuant software using a single compartment Rb-82 model. Global myocardial blood flow under pharmacological stress for the 24 females as measured by PMOD, syngo MBF, and FlowQuant were 3.10 ± 0.72, 2.80 ± 0.66, and 2.60 ± 0.63 mL·minute(-1)·g(-1), and for the 25 males was 2.60 ± 0.84, 2.33 ± 0.75, 2.15 ± 0.62 mL·minute(-1)·g(-1), respectively. Rest flows for PMOD, syngo MBF, and FlowQuant averaged 1.32 ± 0.42, 1.20 ± 0.33, and 1.06 ± 0.38 mL·minute(-1)·g(-1) for the female subjects, and 1.12 ± 0.29, 0.90 ± 0.26, and 0.85 ± 0.24 mL·minute(-1)·g(-1) for the males. Myocardial flow reserves for PMOD, syngo MBF, and FlowQuant for the female normals were calculated to be 2.50 ± 0.80, 2.53 ± 0.67, 2.71 ± 0.90, and 2.50 ± 1.19, 2

Effects of aspirin plus extended-release dipyridamole versus clopidogrel and telmisartan on disability and cognitive function after recurrent stroke in patients with ischaemic stroke in the Prevention Regimen for Effectively Avoiding Second Strokes (PRoFESS) trial : a double-blind, active and placebo-controlled study

NARCIS (Netherlands)

Dienert, Hans-Christoph; Saccot, Ralph L.; Yusuft, Salim; Cotton, Daniel; Ounpuu, Stephanie; Lawton, William A.; Palesch, Yuko; Martin, Renee H.; Albers, Gregory W.; Bath, Philip; Bornstein, Natan; Chan, Bernard P. L.; Chen, Sien-Tsong; Cunha, Luis; Dahlof, Bjorn; De Keyser, Jacques; Donnan, Geoffrey A.; Estol, Conrado; Gorelick, Philip; Gu, Vivian; Hermansson, Karin; Hilbrich, Lutz; Kaste, Markku; Lu, Chuanzhen; Machnig, Thomas; Pais, Prem; Roberts, Robin; Skvortsova, Veronika; Teal, Philip; Toni, Danilo; VanderMaelen, Cam; Voigt, Thor; Weber, Michael; Yoon, Byung-Woo

2008-01-01

Background The treatment of ischaemic stroke with neuroprotective drugs has been unsuccessful, and whether these compounds can be used to reduce disability after recurrent stroke is unknown. The putative neuroprotective effects of antiplatelet compounds and the angiotensin II receptor antagonist

Effect of batroxobin combine with ginkgo-damole injection on hemodynamics, coagulation function, fibrinolytic function and related factors in patients with sudden deafness

Directory of Open Access Journals (Sweden)

Xiang Xu

2017-11-01

Full Text Available Objective: To study the effects of combined use of Batroxobin and Ginkgo Leaf Extract and Dipyridamole Injection on hemodynamics, coagulation function, fibrinolytic function and related factors in patients with sudden deafness. Methods: A total of 94 patients with sudden deafness in our hospital were selected, and divided them into control group and observation group randomly, 47 cases in each group. All patients were given 10BU batroxobin injection intravenous drip after admission every other day; And the patients of observation group were given intravenous drip of 30ml ginkgo-damole injection, 1 time a day. The hemodynamics, coagulation function, fibrinolytic function and related factors were detected and compared between the two groups before and after treatment. Results: Before treatment, there was no statistical difference in hemodynamics, coagulation function, fibrinolytic function and related factors between the two groups; After treatment, the levels of WBV and PV in the control group was (5.21±0.58 mPa/s and (1.78±0.32 mPa/s, and the observation group was (4.13±0.47 mPa/s and (1.31±0.26 mPa/s, compared with the same group before treatment, there were statistical difference, and there was also statistical difference between the two groups; The levels of PT, APTT, TT and PF was (19.22±3.98 s, (43.57±9.88 s, (15.64±3.27 s and (58.22±10.58 μg/L, and the observation group was (23.97±4.82 s, (52.49±10.38 s, (20.59±4.15 s and (41.03±8.46 μg/L, compared with the same group before treatment, there were statistical difference, and there was also statistical difference between the two groups; The levels of Fib, D-dimer and FDP was (4.52±0.93 g/L, (6.53±1.88 mg/L and (8.17±2.34 μg/mL, and the observation group was (3.13±0.75 g/L, (9.75±2.14 mg/L, (13.52±2.58 μg/ mL, compared with the same group before treatment, there were statistical difference, and there was also statistical difference between the two groups; The serum

Persistence of normal cardiac function and myocardial perfusion in irradiated long-term survivors of Hodgkin's disease

International Nuclear Information System (INIS)

Constine, L.S.; Schwartz, R.G.; Savage, D.E.; King, V.; Muhs, A.; Rubin, P.

1996-01-01

Purpose: The risk of myocardial infarction and cardiac dysfunction following mantle irradiation (RT) for Hodgkin's disease is controversial. The relative risk of fatal myocardial infarction is 2.8 in our Hodgkin's patients, similar to other reports. Sensitive evaluations of cardiac function and myocardial perfusion might be expected to reveal pre-clinical abnormalities of potential significance. We hypothesized the presence of pre-clinical cardiac toxicity and progressive deterioration of left ventricular performance and myocardial ischemia over time in long-term survivors of Hodgkin's disease. The data reported herein extend our previous study in patient number (n=50) and follow-up duration (mean 16.5 years). Materials and Methods: Equilibrium radionuclide angiocardiography (ERNA) was used to quantify left ventricular (LV) systolic and diastolic function with LV ejection fraction (LVEF) and peak filling rate (PFR), respectively. Quantitative myocardial perfusion scintigraphy (MPS) and ECG stress testing with exercise or dipyridamole were used to assess myocardial perfusion and electrical function. Patients at least 1.0 year after RT were eligible if ≤ 50 years old at RT and without known Hodgkin's or cardiac disease. Fifty patients, ages 10-46 years (mean 26.0) at RT, were tested 1.1 to 29.1 years (mean 9.1) after RT. Seventeen patients were tested 2 - 3 times separated by 0.5 - 6.5 years (mean 3.3). The mean central cardiac RT dose was 35.1 Gy (range 18.5 - 47.5) in daily 1.5-2.0 Gy fractions. Twelve patients were additionally irradiated to the left ventricle (LVRT), usually through partial transmission left lung shields (range 14.3-21.3 Gy). Results: No patient had symptomatic cardiac disease at the time of evaluation. The mean LVEF (first test, n = 50) was 60 ± 6% (range 42-73%) [normal ≥ 50%], and PFR (first test, n=44) was 3.43 ± 0.83 end diastolic volume per second (range 1.5-5.2 EDV/sec) [normal ≥ 2.54 EDV/sec] with 2 and 7 patients below normal

Preclinical pharmacological study of 99mTcN(NOET)2 and comparison with 201Tl in redistribution of ischemia myocardium

International Nuclear Information System (INIS)

Wang, J.C.; Zhang, J.B.; Wang, Q.; Mi, H.Z.; Wang, X.B.

2002-01-01

Aim: To study the biological properties of the myocardial imaging agent 99m TcN(NOET) 2 and compare with 201 Tl in redistribution of ischemia myocardium. Materials and Methods: To prepared the 99m TcN(NOET) 2 complex, the intermediate [ 99m TcN] 2+ and ligand NOET were synthesized. In the presence of reducer and the doner of N, the [ 99m Tc=N] 2+ could be synthesized at 100, then NOET was added, 99m TcN(NOET) 2 was formed at room temperature. 201 Tl was provided by the Department of Isotope, China Institute of Atomic Energy. Five dogs were from the Fu Wai experimental animal feeding center, two of them were made into ischemia myocardium models by ligating some coronary artery branches were demonstrated by X-ray coronary angiography, the extent of stenosis of those blood vessels was over 90%. Dynamic imaging of rest was performed respectively in three normal dogs after injecting a dose of 555MBq (15mCi) of 99m TcN(NOET) 2 complex up to two hours. The whole body imaging planar and tomography imaging was carried out respectively at fixed time intervals during two hours in order to obtain the time-activity curves of heart, lung and liver, in vivo biodistribution and quality analysis of myocardial images. Moreover, intravenous blood samples were collected at different times to gain the kinetics of blood clearance. Stress and redistribution imaging underwent in two dogs with ischemia myocardium. Dipyridamol was given intravenously at a dose of 0.6mg/Kg in 4 mins. Stress :9 9m TcN(NOET) 2 myocardial SPECT imaging was performed at 30, 70 and 110 min after injection of 99m TcN(NOET) 2 complex, stress 201 Tl myocardial SPECT imaging was carried out 10 min and redistribution imaging 4 hr after injection of 55.5MBq (1.5mCi) 201 Tl chloride. The tests of 99m TcN(NOET) 2 and 201 Tl were performed respectively in the same dog within 10 days, in order to obtain a comparison between two myocardial redistribution imaging. Results: Radiochemical purity of 99m TcN(NOET) 2 was 98.41%�

[Acute sensorineural hearing loss at the Otorhinolaryngology Department of the General Hospital in Subotica 1991-1996].

Science.gov (United States)

Rakić, N

1999-01-01

. This test was made after passing an acute attack of vertiginous symptoms. Control audiometry was made on the seventh and on the fourteenth day after admission. This therapy consisted of an infusion of physiologic solution (NaCl) 250 or 500 ml twice daily to which 300 mg xanthinol nicotinate ampulla, paracetam 1 g ampulla, dipyridamole 10 mg ampulla and C-vitamin 10% 500 mg ampulla were applied. The number of paracetam and xanthinol nicotinate ampullas was raised on the 14/day, and then it fell to the starting value. The therapy lasted 17 days. Patients were given multivitamine peroral therapy, tranquilizers and diet without coffee, smoking and allergenic food. The study included 53 patients, 27 (50.94%) female and 26 (49.06%) males (Graph 1). Their age (Graph 2) ranged between 16-71 years. The biggest group of patients was between 40-49 (39.62%) years of age. Distribution per year (Graph 3) shows that the incidence of the acute sensorineural hearing loss differs from the findings of other authors, especially in the period of 1991-1994, due to very few cases. Connection of this illness with seasons is shown in Graph 4. We had most cases during summer time (August, 16.98%). There is a mild rise in winter (December, 13.21%). The degree of the hearing loss in decibels is shown in the Graph 5. Most of the patients (75.47%) had mild or severely damaged hearing (40-85 dB). Period of the deafness before patients were admitted to the hospital, is shown in Graph 7. Most of them came in the first seven days after they experienced acute deafness (52.83%). Symptomatology of the persons with acute hearing loss is shown in Table 1. All of them had the feeling of deafness, and 50.94% also had tinnitus. Table 2 shows that only two patients had a pathologic finding (hypo function) on the vestibular caloric test. 57.14% of patients tested by this method showed a normal function of the vestibular apparatus. The recovery of he