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Sample records for coronary blood flow

  1. The Physics of Coronary Blood Flow

    CERN Document Server

    Zamir, M

    2005-01-01

    Coronary blood flow is blood flow to the heart for its own metabolic needs. In the most common form of heart disease there is a disruption in this flow because of obstructive disease in the vessels that carry the flow. The subject of coronary blood flow is therefore associated mostly with the pathophysiology of this disease, rarely with dynamics or physics. Yet, the system responsible for coronary blood flow, namely the "coronary circulation," is a highly sophisticated dynamical system in which the dynamics and physics of the flow are as important as the integrity of the conducting vessels. While an obstruction in the conducting vessels is a fairly obvious and clearly visible cause of disruption in coronary blood flow, any discord in the complex dynamics of the system can cause an equally grave, though less conspicuous, disruption in the flow. This book is devoted specifically to the dynamics and physics of coronary blood flow. While relevance to the clinical and pathophysiological issues is clearly maintaine...

  2. Left coronary arterial blood flow: Noninvasive detection by Doppler US

    International Nuclear Information System (INIS)

    Gramiak, R.; Holen, J.; Moss, A.J.; Gutierrez, O.H.; Picone, A.L.; Roe, S.A.

    1986-01-01

    Continuous wave (CW) and pulsed Doppler ultrasound studies with spectral analysis were used to detect the left coronary arterial blood flow in patients who were undergoing routine echocardiography. The pulmonary artery is a stable ultrasonic landmark from which detection of the blood flow can be effected. The left coronary artery can be distinguished by its blood flow toward the cardiac apex and by specific, functional flow features. Flow patterns vary among the left main, circumflex, and anterior descending arteries; patterns also vary with respiration cycles. In the present study, coronary arterial blood flow was detected in 58 of 70 patients (83%). Findings were validated by selectively injecting an agitated saline contrast medium into the left coronary artery and, in another study, by comparing human Doppler phasic flow waveforms with electromagnetic flowmeter recordings obtained in dogs

  3. The effect of blood cell count on coronary flow in patients with coronary slow flow phenomenon.

    Science.gov (United States)

    Soylu, Korhan; Gulel, Okan; Yucel, Huriye; Yuksel, Serkan; Aksan, Gokhan; Soylu, Ayşegül İdil; Demircan, Sabri; Yılmaz, Ozcan; Sahin, Mahmut

    2014-09-01

    The coronary slow flow phenomenon (CSFP) is a coronary artery disease with a benign course, but its pathological mechanisms are not yet fully understood.The purpose of this controlled study was to investigate the cellular content of blood in patients diagnosed with CSFP and the relationship of this with coronary flow rates. Selective coronary angiographies of 3368 patients were analyzed to assess Thrombolysis in Myocardial Infarction (TIMI) frame count (TFC) values. Seventy eight of them had CSFP, and their demographic and laboratory findings were compared with 61 patients with normal coronary flow. Patients' demographic characteristics were similar in both groups. Mean corrected TFC (cTFC) values were significantly elevated in CSFP patients (p<0.001). Furthermore, hematocrit and hemoglobin values, and eosinophil and basophil counts of the CSFP patients were significantly elevated compared to the values obtained in the control group (p=0.005, p=0.047, p=0.001 and p=0.002, respectively). The increase observed in hematocrit and eosinophil levels showed significant correlations with increased TFC values (r=0.288 and r=0.217, respectively). Significant changes have been observed in the cellular composition of blood in patients diagnosed with CSFP as compared to the patients with normal coronary blood flow. The increases in hematocrit levels and in the eosinophil and basophil counts may have direct or indirect effects on the rate of coronary blood flow.

  4. MR measurement of coronary arterial blood flow velocity. Evaluation of age, stenosis and drugs as factors affecting coronary blood flow

    International Nuclear Information System (INIS)

    Taoka, Yoshiaki; Harada, Masafumi; Nishitani, Hiromu; Yukinaka, Michiko; Nomura, Masahiro

    1998-01-01

    Coronary arterial blood flow velocity was measured using MRI. Two types of phase contrast methods were used for the measurements, one of which exhibited good resolving power whereas the other provided more distinct images acquired while the subject patients held their breath. Before measuring coronary arterial blood flow velocity, accuracy of the two phase contrast methods was evaluated using a phantom. The results obtained with both methods largely agreed with the values obtained using the phantom. Using both methods, the patterns of coronary arterial blood flow over one cardiac cycle were essentially identical. A peak was noted in late systole or in early diastole in the right coronary artery, whereas in the left coronary artery, a peak was noted somewhat later in diastole. In healthy volunteers, no significant difference in the maximal flow velocity in the coronary arteries was found from one age group to another. Among patients with coronary arterial stenosis, coronary arterial blood flow velocity central to the area of stenosis was lower than that observed in the healthy volunteers. Coronary arterial blood flow velocity was observed to decrease after administration of isosorbide dinitrate and increased following administration of nifedipine. (author)

  5. Coronary blood flow during cardiopulmonary resuscitation in swine

    International Nuclear Information System (INIS)

    Bellamy, R.F.; DeGuzman, L.R.; Pedersen, D.C.

    1984-01-01

    Recent papers have raised doubt as to the magnitude of coronary blood flow during closed-chest cardiopulmonary resuscitation. We will describe experiments that concern the methods of coronary flow measurement during cardiopulmonary resuscitation. Nine anesthetized swine were instrumented to allow simultaneous measurements of coronary blood flow by both electromagnetic cuff flow probes and by the radiomicrosphere technique. Cardiac arrest was caused by electrical fibrillation and closed-chest massage was performed by a Thumper (Dixie Medical Inc., Houston). The chest was compressed transversely at a rate of 66 strokes/min. Compression occupied one-half of the massage cycle. Three different Thumper piston strokes were studied: 1.5, 2, and 2.5 inches. Mean aortic pressure and total systemic blood flow measured by the radiomicrosphere technique increased as Thumper piston stroke was lengthened (mean +/- SD): 1.5 inch stroke, 23 +/- 4 mm Hg, 525 +/- 195 ml/min; 2 inch stroke, 33 +/- 5 mm Hg, 692 +/- 202 ml/min; 2.5 inch stroke, 40 +/- 6 mm Hg, 817 +/- 321 ml/min. Both methods of coronary flow measurement (electromagnetic [EMF] and radiomicrosphere [RMS]) gave similar results in technically successful preparations (data expressed as percent prearrest flow mean +/- 1 SD): 1.5 inch stroke, EMF 12 +/- 5%, RMS 16 +/- 5%; 2 inch stroke, EMF 30 +/- 6%, RMS 26 +/- 11%; 2.5 inch stroke, EMF 50 +/- 12%, RMS 40 +/- 20%. The phasic coronary flow signal during closed-chest compression indicated that all perfusion occurred during the relaxation phase of the massage cycle. We concluded that coronary blood flow is demonstrable during closed-chest massage, but that the magnitude is unlikely to be more than a fraction of normal

  6. Coronary blood flow and coronary stenosis correlations in ischemic heart patients

    International Nuclear Information System (INIS)

    Manukov, I.

    2003-01-01

    The aim of the study is the assessment of the methodology for the C-TIMI frame count by Gibson for easy and fast determination of the coronary blood flow during a selective coronary angiography. 75 patient have been studied with one-branch affection of the coronary arteries. The criteria for exclusion are: myocardial hypertrophy, valve lesions, myocardial infarction and dyslipidemia. Depending of the characteristics of the coronary stenotic changes, the patients have been divided into two groups: 1) Patients with 'ordinary' stenosis of the coronary artery and 2) Patients with 'complex' stenosis. The severity of the stenotic changes in percents is the same for the two groups - 78%±13% vs 81±12%, respectively. In the first group a pronounced correlation is observed between the severity of the coronary stenosis and the slowing of the coronary blood flow. The 'threshold' stenotic level is 89%. In the second group the lowest value of the coronary stenosis is 73% (p>0.01 vs group 1). No correlation is observed between the severity of the coronary stenosis and the slowing of the coronary blood flow. A conclusion is made that the Gibson method for the assessment of the blood flow is convenient for the daily practice not only for the assessment of the significance of the coronary changes, but also for fast analysis of the achieved reconstruction of the coronary arteries after angioplasty. Additional studies of the significance of the different signs of 'complexity' of the coronary stenosis for the slowing of the blood flow are necessary

  7. Inversion prepared coronary MR angiography: direct visualization of coronary blood flow

    International Nuclear Information System (INIS)

    Katoh, M.; Spuentrup, E.; Buecker, A.; Guenther, R.W.; Stuber, M.; Manning, W.J.; Botnar, R.M.

    2005-01-01

    Purpose: visualization of coronary blood flow by means of a slice-selective inversion pre-pulse in concert with bright-blood coronary MRA. Materials and methods: coronary magnetic resonance angiography (MRA) of the right coronary artery (RCA) was performed in eight healthy adult subjects on a 1.5 Tesla MR system (Gyroscan ACS-NT, Philips Medical Systems, Best, NL) using a free-breathing navigator-gated and cardiac-triggered 3D steady-state free-precession (SSFP) sequence with radial k-space sampling. Imaging was performed with and without a slice-selective inversion pre-pulse, which was positioned along the main axis of the coronary artery but perpendicular to the imaging volume. Objective image quality parameters such as SNR, CNR, maximal visible vessel length, and vessel border definition were analyzed. Results: in contrast to conventional bright-blood 3D coronary MRA, the selective inversion pre-pulse provided a direct measure of coronary blood flow. In addition, CNR between the RCA and right ventricular blood pool was increased and the vessels had a tendency towards better delineation. Blood SNR and CNR between right coronary blood and epicardial fat were comparable in both sequences. (orig.)

  8. The effects of fenoldopam on coronary conduit blood flow after coronary artery bypass graft surgery.

    LENUS (Irish Health Repository)

    Halpenny, M

    2012-02-03

    OBJECTIVE: To quantify the effects of fenoldopam, 0.1 microg\\/kg\\/min, on left internal mammary artery (LIMA) and saphenous vein blood flow after coronary anastomosis. DESIGN: Prospective, randomized, double-blind, placebo-controlled trial. SETTING: University teaching hospital, single institution. PARTICIPANTS: Thirty-one American Society of Anesthesiologists III patients undergoing elective coronary revascularization. INTERVENTIONS: A perivascular ultrasonic flow probe (Linton Instrumentation, Norfolk, UK) was placed around the LIMA and saphenous vein graft after coronary anastomosis. MEASUREMENTS AND MAIN RESULTS: Immediately before and at 5-minute intervals for 15 minutes after starting the infusion, blood flow was measured in the LIMA and one saphenous vein graft using a transit time ultrasonic flow probe. Heart rate, blood pressure, and central venous pressure were documented at these time points. Administration of fenoldopam, 0.1 microg\\/kg\\/min, did not alter heart rate or blood pressure. A small, nonsignificant increase in LIMA blood flow occurred during the 15-minute study period (30 +\\/- 12 to 35 +\\/- 10 mL\\/min) in patients who received fenoldopam. No significant changes occurred in the placebo group. CONCLUSIONS: The findings indicate that fenoldopam, 0.1 microg\\/kg\\/min, did not influence coronary conduit blood flow to a clinically significant extent. The small increase in LIMA blood flow may be of greater importance in high-risk patients or in the prevention of coronary arterial spasm.

  9. Inhibition of coronary blood flow by a vascular waterfall mechanism.

    Science.gov (United States)

    Downey, J M; Kirk, E S

    1975-06-01

    The mechanism whereby systole inhibits coronary blood flow was examined. A branch of the left coronary artery was maximally dilated with an adenosine infusion, and the pressure-flow relationship was obtained for beating and arrested states. The pressure-flow curve for the arrested state was shifted toward higher pressures and in the range of pressures above peak ventricular pressure was linear and parallel to that for the arrested state. Below this range the curve for the beating state converged toward that for the arrested state and was convex to the pressure axis. These results were compared with a model of the coronary vasculature that consisted of numerous parallel channels, each responding to local intramyocardial pressure by forming vascular waterfalls. When intramyocardial pressure in the model was assigned values from zero at the epicardium to peak ventricular pressure at the endocardium, pressure-flow curves similar to the experimental ones resulted. Thus, we conclude that systole inhibits coronary perfusion by the formation of vascular waterfalls and that the intramyocardial pressures responsible for this inhibition do not significantly exceed peak ventricular pressure.

  10. Quantitative imaging of coronary blood flow

    Directory of Open Access Journals (Sweden)

    Adam M. Alessio

    2010-04-01

    Radiology. In 1979, he established a National Simulation Resource Facility in Circulatory Mass Transport and Exchange and in 1997, he initiated the Human Physiome Projects. He is a member of the US National Academy of Engineering. His research is on quantitative integration of cellular and cardiovascular systems.Positron emission tomography (PET is a nuclear medicine imaging modality based on the administration of a positron-emitting radiotracer, the imaging of the distribution and kinetics of the tracer, and the interpretation of the physiological events and their meaning with respect to health and disease. PET imaging was introduced in the 1970s and numerous advances in radiotracers and detection systems have enabled this modality to address a wide variety of clinical tasks, such as the detection of cancer, staging of Alzheimer's disease, and assessment of coronary artery disease (CAD. This review provides a description of the logic and the logistics of the processes required for PET imaging and a discussion of its use in guiding the treatment of CAD. Finally, we outline prospects and limitations of nanoparticles as agents for PET imaging.

  11. Myocardial blood flow in patients with coronary disease while in active employment

    International Nuclear Information System (INIS)

    Kahn, P.; Heeger, H.; Aldor, E.; Hanuschkrankenhaus, Vienna

    1975-01-01

    In the course of coronary angiographies the blood flow of the right and the left coronary artery was determined by the 133 Xe lavage method in 89 patients with coronary heart disease. There was a statistically significant difference between the flow values of the LCA and RCA, while there was none between the blood flow values of blue- and white-collar workers suffering from coronary artery disease. Also a significantly better blood circulation of the right as well as of the left coronary artery was found in female employees in comparison to male employees. (orig.) [de

  12. Recruitable collateral blood flow index predicts coronary instent restenosis after percutaneous coronary intervention

    DEFF Research Database (Denmark)

    Jensen, Lisette Okkels; Thayssen, Per; Lassen, Jens Flensted

    2007-01-01

    AIMS: Collateral flow may influence long-term results after percutaneous coronary intervention (PCI) because of haemodynamic forces compete with the antegrade flow through the dilated lesion. The aim of the study was to assess the influence of recruitable collateral blood flow on restenosis...... in patients undergoing PCI with bare metal stents and using optimal antithrombotic treatment. METHODS AND RESULTS: In 95 patients, 95 de novo lesions were treated with PCI and a bare metal stent. Fractional flow reserve (FFR) at maximum hyperaemia induced by intravenous adenosine was determined. The pressure.......02-1.12, P = 0.016). CONCLUSION: Recruitable collateral blood flow measured during balloon inflation predicts angiographic instent restenosis in PCI patients treated with bare metal stents. Udgivelsesdato: 2007-Aug...

  13. Successful percutaneous coronary intervention significantly improves coronary sinus blood flow as assessed by transthoracic echocardiography.

    Science.gov (United States)

    Lyubarova, Radmila; Boden, William E; Fein, Steven A; Schulman-Marcus, Joshua; Torosoff, Mikhail

    2018-06-01

    Transthoracic echocardiography (TTE) has been used to assess coronary sinus blood flow (CSBF), which reflects total coronary arterial blood flow. Successful angioplasty is expected to improve coronary arterial blood flow. Changes in CSBF after percutaneous coronary intervention (PCI), as assessed by TTE, have not been systematically evaluated. TTE can be utilized to reflect increased CSBF after a successful, clinically indicated PCI. The study cohort included 31 patients (18 females, 62 ± 11 years old) referred for diagnostic cardiac catheterization for suspected coronary artery disease and possible PCI, when clinically indicated. All performed PCIs were successful, with good angiographic outcome. CSBF per cardiac cycle (mL/beat) was measured using transthoracic two-dimensional and Doppler flow imaging as the product of coronary sinus (CS) area and CS flow time-velocity integral. CSBF per minute (mL/min) was calculated as the product of heart rate and CSBF per cardiac cycle. In each patient, CSBF was assessed prospectively, before and after cardiac catheterization with and without clinically indicated PCI. Within- and between-group differences in CSBF before and after PCI were assessed using repeated measures analysis of variance. Technically adequate CSBF measurements were obtained in 24 patients (77%). In patients who did not undergo PCI, there was no significant change in CSBF (278.1 ± 344.1 versus 342.7 ± 248.5, p = 0.36). By contrast, among patients who underwent PCI, CSBF increased significantly (254.3 ± 194.7 versus 618.3 ± 358.5 mL/min, p < 0.01, p-interaction = 0.03). Other hemodynamic and echocardiographic parameters did not change significantly before and after cardiac catheterization in either treatment group. Transthoracic echocardiographic assessment can be employed to document CSBF changes after angioplasty. Future studies are needed to explore the clinical utility of this noninvasive metric.

  14. Regulation of Coronary Blood Flow in Health and Ischemic Heart Disease

    Science.gov (United States)

    Duncker, Dirk J.; Koller, Akos; Merkus, Daphne; Canty, John M.

    2018-01-01

    The major factors determining myocardial perfusion and oxygen delivery have been elucidated over the past several decades, and this knowledge has been incorporated into the management of patients with ischemic heart disease (IHD). The basic understanding of the fluid mechanical behavior of coronary stenoses has also been translated to the cardiac catheterization laboratory where measurements of coronary pressure distal to a stenosis and coronary flow are routinely obtained. However, the role of perturbations in coronary microvascular structure and function, due to myocardial hypertrophy or coronary microvascular dysfunction, in IHD is becoming increasingly recognized. Future studies should therefore be aimed at further improving our understanding of the integrated coronary microvascular mechanisms that control coronary blood flow, and of the underlying causes and mechanisms of coronary microvascular dysfunction. This knowledge will be essential to further improve the treatment of patients with IHD. PMID:25475073

  15. Novel monorail infusion catheter for volumetric coronary blood flow measurement in humans: in vitro validation.

    Science.gov (United States)

    van 't Veer, Marcel; Adjedj, Julien; Wijnbergen, Inge; Tóth, Gabor G; Rutten, Marcel C M; Barbato, Emanuele; van Nunen, Lokien X; Pijls, Nico H J; De Bruyne, Bernard

    2016-08-20

    The aim of this study is to validate a novel monorail infusion catheter for thermodilution-based quantitative coronary flow measurements. Based on the principles of thermodilution, volumetric coronary flow can be determined from the flow rate of a continuous saline infusion, the temperature of saline when it enters the coronary artery, and the temperature of the blood mixed with the saline in the distal part of the coronary artery. In an in vitro set-up of the systemic and coronary circulation at body temperature, coronary flow values were varied from 50-300 ml/min in steps of 50 ml/min. At each coronary flow value, thermodilution-based measurements were performed at infusion rates of 15, 20, and 30 ml/min. Temperatures and pressures were simultaneously measured with a pressure/temperature sensor-tipped guidewire. Agreement of the calculated flow and the measured flow as well as repeatability were assessed. A total of five catheters were tested, with a total of 180 measurements. A strong correlation (ρ=0.976, p<0.0001) and a difference of -6.5±15.5 ml/min were found between measured and calculated flow. The difference between two repeated measures was 0.2%±8.0%. This novel infusion catheter used in combination with a pressure/temperature sensor-tipped guidewire allows accurate and repeatable absolute coronary flow measurements. This opens a window to a better understanding of the coronary microcirculation.

  16. Influence of type of aortic valve prosthesis on coronary blood flow velocity.

    Science.gov (United States)

    Jelenc, Matija; Juvan, Katja Ažman; Medvešček, Nadja Tatjana Ružič; Geršak, Borut

    2013-02-01

    Severe aortic valve stenosis is associated with high resting and reduced hyperemic coronary blood flow. Coronary blood flow increases after aortic valve replacement (AVR); however, the increase depends on the type of prosthesis used. The present study investigates the influence of type of aortic valve prosthesis on coronary blood flow velocity. The blood flow velocity in the left anterior descending coronary artery (LAD) and the right coronary artery (RCA) was measured intraoperatively before and after AVR with a stentless bioprosthesis (Sorin Freedom Solo; n = 11) or a bileaflet mechanical prosthesis (St. Jude Medical Regent; n = 11). Measurements were made with an X-Plore epicardial Doppler probe (Medistim, Oslo, Norway) following induction of hyperemia with an adenosine infusion. Preoperative and postoperative echocardiography evaluations were used to assess valvular and ventricular function. Velocity time integrals (VTI) were measured from the Doppler signals and used to calculate the proportion of systolic VTI (SF), diastolic VTI (DF), and normalized systolic coronary blood flow velocities (NSF) and normalized diastolic coronary blood flow velocities (NDF). The systolic proportion of the LAD VTI increased after AVR with the St. Jude Medical Regent prosthesis, which produced higher LAD SF and NSF values than the Sorin Freedom Solo prosthesis (SF, 0.41 ± 0.09 versus 0.29 ± 0.13 [P = .04]; NSF, 0.88 ± 0.24 versus 0.55 ± 0.17 [P = .01]). No significant changes in the LAD velocity profile were noted after valve replacement with the Sorin Freedom Solo, despite a significant reduction in transvalvular gradient and an increase in the effective orifice area. AVR had no effect on the RCA flow velocity profile. The coronary flow velocity profile in the LAD was significantly influenced by the type of aortic valve prosthesis used. The differences in the LAD velocity profile probably reflect differences in valve design and the systolic transvalvular flow pattern.

  17. Role of adenosine in the regulation of coronary blood flow in swine at rest and during treadmill exercise

    NARCIS (Netherlands)

    D.J.G.M. Duncker (Dirk); R. Stubenitsky (René); P.D. Verdouw (Pieter)

    1998-01-01

    textabstractA pivotal role for adenosine in the regulation of coronary blood flow is still controversial. Consequently, we investigated its role in the regulation of coronary vasomotor tone in swine at rest and during graded treadmill exercise. During exercise,

  18. Moderate exercise training promotes adaptations in coronary blood flow and adenosine production in normotensive rats

    Science.gov (United States)

    Roque, Fernanda R.; Soci, Ursula Paula Renó; De Angelis, Katia; Coelho, Marcele A.; Furstenau, Cristina R.; Vassallo, Dalton V.; Irigoyen, Maria Claudia; Oliveira, Edilamar M.

    2011-01-01

    OBJECTIVES: Aerobic exercise training prevents cardiovascular risks. Regular exercise promotes functional and structural adaptations that are associated with several cardiovascular benefits. The aim of this study is to investigate the effects of swimming training on coronary blood flow, adenosine production and cardiac capillaries in normotensive rats. METHODS: Wistar rats were randomly divided into two groups: control (C) and trained (T). An exercise protocol was performed for 10 weeks and 60 min/day with a tail overload of 5% bodyweight. Coronary blood flow was quantified with a color microsphere technique, and cardiac capillaries were quantified using light microscopy. Adenine nucleotide hydrolysis was evaluated by enzymatic activity, and protein expression was evaluated by western blot. The results are presented as the means ± SEMs (p<0.05). RESULTS: Exercise training increased the coronary blood flow and the myocardial capillary-to-fiber ratio. Moreover, the circulating and cardiac extracellular adenine nucleotide hydrolysis was higher in the trained rats than in the sedentary rats due to the increased activity and protein expression of enzymes, such as E-NTPDase and 5′-nucleotidase. CONCLUSIONS: Swimming training increases coronary blood flow, number of cardiac capillaries, and adenine nucleotide hydrolysis. Increased adenosine production may be an important contributor to the enhanced coronary blood flow and angiogenesis that were observed in the exercise-trained rats; collectively, these results suggest improved myocardial perfusion. PMID:22189737

  19. Moderate exercise training promotes adaptations in coronary blood flow and adenosine production in normotensive rats

    Directory of Open Access Journals (Sweden)

    Fernanda R. Roque

    2011-01-01

    Full Text Available OBJECTIVES: Aerobic exercise training prevents cardiovascular risks. Regular exercise promotes functional and structural adaptations that are associated with several cardiovascular benefits. The aim of this study is to investigate the effects of swimming training on coronary blood flow, adenosine production and cardiac capillaries in normotensive rats. METHODS: Wistar rats were randomly divided into two groups: control (C and trained (T. An exercise protocol was performed for 10 weeks and 60 min/day with a tail overload of 5% bodyweight. Coronary blood flow was quantified with a color microsphere technique, and cardiac capillaries were quantified using light microscopy. Adenine nucleotide hydrolysis was evaluated by enzymatic activity, and protein expression was evaluated by western blot. The results are presented as the means ± SEMs (p<0.05. RESULTS: Exercise training increased the coronary blood flow and the myocardial capillary-to-fiber ratio. Moreover, the circulating and cardiac extracellular adenine nucleotide hydrolysis was higher in the trained rats than in the sedentary rats due to the increased activity and protein expression of enzymes, such as E-NTPDase and 59- nucleotidase. CONCLUSIONS: Swimming training increases coronary blood flow, number of cardiac capillaries, and adenine nucleotide hydrolysis. Increased adenosine production may be an important contributor to the enhanced coronary blood flow and angiogenesis that were observed in the exercise-trained rats; collectively, these results suggest improved myocardial perfusion.

  20. Effect of atrial systole on canine and porcine coronary blood flow.

    Science.gov (United States)

    Bellamy, R F

    1981-09-01

    A feature of phasic coronary flow patterns recorded in conscious chronically instrumented dogs is the atrial cove--a transient depression of arterial flow that occurs during atrial systole. The association between the hemodynamic effects of atrial systole and the atrial cove was studied in anesthetized dogs and pigs with complete heart block. Many atrial coves are available for study in these preparations because atrial activity continues unabated during the diastolic ventricular arrest that follows cessation of electrical pacing. The effect of atrial systole is to translate the pressure-flow relation found during diastole to a higher intercept pressure without change in slope. The increase in the intercept pressure equals the increase in intramyocardial pressure measured with microtransducers embedded in the left ventricular wall. The decrement in flow during the atrial cove is a direct function of the change in intramyocardial pressure and an inverse function of coronary vascular resistance. Each atrial systole is associated with a forward flow transient in the coronary veins, the peak of which occurs at the same instant as does the nadir of atrial flow. These data suggest that the coronary vessels are acting as collapsible tubes and that the waterfall model of the coronary circulation is applicable. The following sequence is proposed to account for the atrial cove. Atrial systole ejects a bolus of blood into the left ventricle increasing both ventricular cavity and intramyocardial pressures. The increase in intramyocardial pressure raises the back pressure opposing coronary flow, reducing the arterial perfusion pressure gradient and causing flow to fall.

  1. Computer Simulations of Coronary Blood Flow Through a Constriction

    Science.gov (United States)

    2014-03-01

    for clinical translation. Journal of the American College of Cardiology . 59(15): 1337–1349. Leimgruber, P., Roubin, G., Hollman, J., Cotsonis, G...the artery and increase blood flow. Generally a stent, or a mesh wire tube, is permanently inserted in order to scaffold open the artery wall...central regions of the channel, so the magnitude of the velocity has to be higher in the open area of the channel, overshooting the experimental results

  2. Coronary blood flow in the anesthetized American alligator (Alligator mississippiensis)

    NARCIS (Netherlands)

    Jensen, Bjarke; Elfwing, Magnus; Elsey, Ruth M.; Wang, Tobias; Crossley, Dane A.

    2016-01-01

    Coronary circulation of the heart evolved early within ectothermic vertebrates and became of vital importance to cardiac performance in some teleost fish, mammals and birds. In contrast, the role and function of the coronary circulation in ectothermic reptiles remains largely unknown. Here, we

  3. 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)

  4. Regional blood flow analysis and its relationship with arterial branch lengths and lumen volume in the coronary arterial tree

    International Nuclear Information System (INIS)

    Molloi, Sabee; Wong, Jerry T

    2007-01-01

    The limitations of visually assessing coronary artery disease are well known. These limitations are particularly important in intermediate coronary lesions (30-70% diameter stenosis) where it is difficult to determine whether a particular lesion is the cause of ischaemia. Therefore, a functional measure of stenosis severity is needed. The purpose of this study is to determine whether the expected maximum coronary blood flow in an arterial tree is predictable from its sum of arterial branch lengths or lumen volume. Using a computer model of a porcine coronary artery tree, an analysis of blood flow distribution was conducted through a network of millions of vessels that included the entire coronary artery tree down to the first capillary branch. The flow simulation results show that there is a linear relationship between coronary blood flow and the sum of its arterial branch lengths. This relationship holds over the entire arterial tree. The flow simulation results also indicate that there is a 3/4 er relation between coronary blood flow (Q) and the sum of its arterial lumen volume (V). Moreover, there is a linear relationship between normalized Q and normalized V raised to a power of 3/4 over the entire arterial tree. These results indicate that measured arterial branch lengths or lumen volumes can be used to predict the expected maximum blood flow in an arterial tree. This theoretical maximum blood flow, in conjunction with an angiographically measured blood flow, can potentially be used to calculate fractional flow reserve based entirely on angiographic data

  5. Coronary blood flow and coronary stenosis correlations in ischemic heart patients; Interventsionalni protseduri pod obrazen kontrol v usloviyata na dobolnichnata pomosht

    Energy Technology Data Exchange (ETDEWEB)

    Manukov, I [Plovdiv, (Bulgaria)

    2003-07-01

    The aim of the study is the assessment of the methodology for the C-TIMI frame count by Gibson for easy and fast determination of the coronary blood flow during a selective coronary angiography. 75 patient have been studied with one-branch affection of the coronary arteries. The criteria for exclusion are: myocardial hypertrophy, valve lesions, myocardial infarction and dyslipidemia. Depending of the characteristics of the coronary stenotic changes, the patients have been divided into two groups: 1) Patients with 'ordinary' stenosis of the coronary artery and 2) Patients with 'complex' stenosis. The severity of the stenotic changes in percents is the same for the two groups - 78%{+-}13% vs 81{+-}12%, respectively. In the first group a pronounced correlation is observed between the severity of the coronary stenosis and the slowing of the coronary blood flow. The 'threshold' stenotic level is 89%. In the second group the lowest value of the coronary stenosis is 73% (p>0.01 vs group 1). No correlation is observed between the severity of the coronary stenosis and the slowing of the coronary blood flow. A conclusion is made that the Gibson method for the assessment of the blood flow is convenient for the daily practice not only for the assessment of the significance of the coronary changes, but also for fast analysis of the achieved reconstruction of the coronary arteries after angioplasty. Additional studies of the significance of the different signs of 'complexity' of the coronary stenosis for the slowing of the blood flow are necessary.

  6. Effects of ranolazine on ischemic threshold, coronary sinus blood flow, and myocardial metabolism in coronary artery disease.

    Science.gov (United States)

    Bagger, J P; Bøtker, H E; Thomassen, A; Nielsen, T T

    1997-07-01

    Cytoprotection or metabolic modulation is a new principle in the treatment of angina pectoris. The effect of ranolazine (a cytoprotective drug) on ischemic threshold, coronary sinus blood flow, and myocardial metabolism was evaluated by means of two pacing sequences in nine male patients with coronary artery disease (CAD) and in eight male controls. Ranolazine was given as an intravenous bolus followed by continuous infusion; the mean total dose was 32.7 mg and 31.7 mg in patients and controls, respectively. Angina pectoris was relieved in two patients after ranolazine but pacing time to pain was unchanged in the remaining patients. Maximal ST depression was lower (p = 0.02), but pacing time to maximal and to 1-mm ST depression remained unchanged after the drug. Ranolazine had no overall influence on coronary sinus blood flow, cardiac oxygen consumption, blood pressure, and heart rate. Cardiac uptake of free fatty acids (FFA) was reduced (p = 0.01), and net uptakes of glucose (p = 0.07) and lactate (p = 0.06) tended to be lower after ranolazine in CAD patients and controls. Ranolazine had no direct influence on cardiac exchange of glutamate, alanine, and citrate or on the arterial concentration of any metabolite. In the present study ranolazine had minimal clinical effects. A decrease in myocardial FFA utilization, however, allows greater myocardial glucose oxidation, which may increase the energy production in relation to oxygen availability.

  7. Prognostic value of coronary blood flow velocity and myocardial perfusion in intermediate coronary Narrowings and multivessel disease

    NARCIS (Netherlands)

    Chamuleau, SAJ; Tio, RA; de Cock, CC; de Muinck, ED; Pijls, NHJ; van Eck-Smit, BLF; Koch, KT; Meuwissen, M; Dijkgraaf, MGW; Verberne, HJ; van Liebergen, RAM; Laarman, GJ; Tijssen, JGP; Piek, JJ; de Jong, A.

    2002-01-01

    OBJECTIVES This study aimed to investigate the roles of intracoronary derived coronary flow velocity reserve (CFVR) and myocardial perfusion scintigraphy (single photon emission computed tomography, or SPECT) for management of an intermediate lesion in patient, with multivessel coronary artery

  8. Progressive epicardial coronary blood flow reduction fails to produce ST-segment depression at normal heart rates.

    Science.gov (United States)

    de Chantal, Marilyn; Diodati, Jean G; Nasmith, James B; Amyot, Robert; LeBlanc, A Robert; Schampaert, Erick; Pharand, Chantal

    2006-12-01

    ST-segment depression is commonly seen in patients with acute coronary syndromes. Most authors have attributed it to transient reductions in coronary blood flow due to nonocclusive thrombus formation on a disrupted atherosclerotic plaque and dynamic focal vasospasm at the site of coronary artery stenosis. However, ST-segment depression was never reproduced in classic animal models of coronary stenosis without the presence of tachycardia. We hypothesized that ST-segment depression occurring during acute coronary syndromes is not entirely explained by changes in epicardial coronary artery resistance and thus evaluated the effect of a slow, progressive epicardial coronary artery occlusion on the ECG and regional myocardial blood flow in anesthetized pigs. Slow, progressive occlusion over 72 min (SD 27) of the left anterior descending coronary artery in 20 anesthetized pigs led to a 90% decrease in coronary blood flow and the development of ST-segment elevation associated with homogeneous and transmural myocardial blood flow reductions, confirmed by microspheres and myocardial contrast echocardiography. ST-segment depression was not observed in any ECG lead before the development of ST-segment elevation. At normal heart rates, progressive epicardial stenosis of a coronary artery results in myocardial ischemia associated with homogeneous, transmural reduction in regional myocardial blood flow and ST-segment elevation, without preceding ST-segment depression. Thus, in coronary syndromes with ST-segment depression and predominant subendocardial ischemia, factors other than mere increases in epicardial coronary resistance must be invoked to explain the heterogeneous parietal distribution of flow and associated ECG changes.

  9. Coronary and muscle blood flow during physical exercise in humans; heterogenic alliance.

    Science.gov (United States)

    Zoladz, Jerzy A; Majerczak, Joanna; Duda, Krzysztof; Chlopicki, Stefan

    2015-08-01

    In this review, we present the relation between power generation capabilities and pulmonary oxygen uptake during incremental cycling exercise in humans and the effect of exercise intensity on the oxygen cost of work. We also discuss the importance of oxygen delivery to the working muscles as a factor determining maximal oxygen uptake in humans. Subsequently, we outline the importance of coronary blood flow, myocardial oxygen uptake and myocardial metabolic stability for exercise tolerance. Finally, we describe mechanisms of endothelium-dependent regulation of coronary and skeletal muscle blood flow, dysregulation of which may impair exercise capacity and increase the cardiovascular risk of exercise. Copyright © 2015 Institute of Pharmacology, Polish Academy of Sciences. All rights reserved.

  10. Dopexamine increases internal mammary artery blood flow following coronary artery bypass grafting.

    LENUS (Irish Health Repository)

    Flynn, Michael J

    2012-02-03

    OBJECTIVE: Vasoactive agents and inotropes influence conduit-coronary blood flow following coronary artery bypass grafting (CABG). It was hypothesized that dopexamine hydrochloride, a dopamine A-1 (DA-1) and beta(2) agonist would increase conduit-coronary blood flow. A prospective randomized double blind clinical trial was carried out to test this hypothesis. DA-1 receptors have previously been localized to human left ventricle. METHODS: Twenty-six American Society of Anaesthesiology class 2-3 elective coronary artery bypass graft patients who did not require inotropic support on separation from cardiopulmonary bypass (CPB) were studied. According to a randomized allocation patients received either dopexamine (1 microg\\/kg per min) or placebo (saline) by intravenous infusion for 15 min. Immediately prior to and at 5,10 and 15 min of infusion, blood flow through the internal mammary and vein grafts (Transit time flow probes, Transonic Ltd.), heart rate, cardiac index, mean arterial pressure and pulmonary haemodynamics were noted. The data were analysed using multivariate analysis of variance. RESULTS: Low-dose dopexamine (1 microg\\/kg per min) caused a significant increase in mammary graft blood flow compared to placebo at 15 min of infusion (P=0.028, dopexamine group left internal mammary artery (LIMA) flow of 43.3+\\/-14.2 ml\\/min, placebo group LIMA flow at 26.1+\\/-16.3 ml\\/min). Dopexamine recipients demonstrated a non-significant trend to increased saphenous vein graft flow (P=0.059). Increased heart rate was the only haemodynamic change induced by dopexamine (P=0.004, dopexamine group at 85.2+\\/-9.6 beats\\/min and placebo group at 71.1+\\/-7.6 beats\\/min after 15 min of infusion). CONCLUSION: This study demonstrates that administration of dopexamine (1 microg\\/kg per min) was associated with a significant increase in internal mammary artery graft blood flow with mild increase in heart rate being the only haemodynamic change. Low-dose dopexamine may

  11. Increased myocardial infarct size because of reduced coronary collateral blood flow in beagles

    International Nuclear Information System (INIS)

    Uemura, N.; Knight, D.R.; Shen, Y.T.; Nejima, J.; Cohen, M.V.; Thomas, J.X. Jr.; Vatner, S.F.

    1989-01-01

    Effects of permanent left circumflex coronary artery occlusion (CAO) were examined in conscious purebred beagles and mongrel dogs, instrumented with miniature left ventricular (LV) pressure gauges, wall thickness gauges in the ischemic zone, catheters in left atrium and aorta, and snares around the left circumflex coronary artery. Blood flow was measured using the radioactive microsphere technique before CAO and at 5 min, 1, 3, and 24 h after CAO. Although CAO reduced myocardial blood flow similarly in beagles and mongrels, significantly less (P less than 0.05) recovery of myocardial blood flow was observed over the following 24-h period in beagles. Infarct size, as determined by triphenyltetrazolium chloride and expressed as percentage of area at risk, was larger (P less than 0.05) in beagles (62.0 ± 5.1%) than mongrels (42.5 ± 4.2%). Thus beagles do not tolerate ischemia as well as mongrel dogs and possess fewer functional coronary collaterals resulting in larger infarcts after CAO

  12. Improved evaluation of the coronary collateral circulation measuring the regional blood flow with 133Xe

    International Nuclear Information System (INIS)

    Franz, N.; Strangfeld, D.; Romaniuk, P.; Heublein, B.

    1988-01-01

    In 40 patients with angina pectoris catheter diagnostic measurements of the myocardial flow were carried out after intracoronary application of 133 Xe at rest and after oral application of Curantyl in order to obtain a better evaluation of coronary collaterals. The results show relations between angiographically detected coronary collaterals and the reduced coronary reserve. A quantitative measurement of collaterals from the angiogram facilitates a more precise evaluation of the relation between coronary sclerosis and myocardial flow. (author)

  13. Iodophenylpentadecanoic acid-myocardial blood flow relationship during maximal exercise with coronary occlusion

    Energy Technology Data Exchange (ETDEWEB)

    Caldwell, J.H.; Martin, G.V.; Link, J.M.; Krohn, K.A.; Bassingthwaighte, J.B. (Seattle VA Medical Center, WA (USA))

    1990-01-01

    Imaging {sup 123}I-labeled iodophenylpentadecanoic acid (IPPA) uptake and clearance from the myocardium following exercise has been advocated as a means of detecting myocardial ischemia because fatty acid deposition is enhanced and clearance prolonged in regions of low flow. However, normal regional myocardial blood flows are markedly heterogeneous, and it is not known how this heterogeneity affects regional metabolism or substrate uptake and thus image interpretation. In five instrumented dogs running at near maximal workload on a treadmill, {sup 131}I-labeled IPPA and 15-micron 46Sc microspheres were injected into the left atrium after 30 sec of circumflex coronary artery occlusion. Microsphere and IPPA activity were determined in 250 mapped pieces of myocardium of approximately 400 mg. Myocardial blood flows (from microspheres) ranged from 0.05 to 7.6 ml/min/g. Deposition of IPPA was proportional to regional flows (r = 0.83) with an average retention of 25%. The mean endocardial-epicardial ratio for IPPA (0.90 {plus minus} 0.43) was similar to that for microspheres (0.94 {plus minus} 0.47; p = 0.08). Thus, initial IPPA deposition during treadmill exercise increases in proportion to regional myocardial blood flow over a range of flows from very low to five times normal.

  14. Iodophenylpentadecanoic acid-myocardial blood flow relationship during maximal exercise with coronary occlusion

    International Nuclear Information System (INIS)

    Caldwell, J.H.; Martin, G.V.; Link, J.M.; Krohn, K.A.; Bassingthwaighte, J.B.

    1990-01-01

    Imaging 123 I-labeled iodophenylpentadecanoic acid (IPPA) uptake and clearance from the myocardium following exercise has been advocated as a means of detecting myocardial ischemia because fatty acid deposition is enhanced and clearance prolonged in regions of low flow. However, normal regional myocardial blood flows are markedly heterogeneous, and it is not known how this heterogeneity affects regional metabolism or substrate uptake and thus image interpretation. In five instrumented dogs running at near maximal workload on a treadmill, 131 I-labeled IPPA and 15-micron 46Sc microspheres were injected into the left atrium after 30 sec of circumflex coronary artery occlusion. Microsphere and IPPA activity were determined in 250 mapped pieces of myocardium of approximately 400 mg. Myocardial blood flows (from microspheres) ranged from 0.05 to 7.6 ml/min/g. Deposition of IPPA was proportional to regional flows (r = 0.83) with an average retention of 25%. The mean endocardial-epicardial ratio for IPPA (0.90 ± 0.43) was similar to that for microspheres (0.94 ± 0.47; p = 0.08). Thus, initial IPPA deposition during treadmill exercise increases in proportion to regional myocardial blood flow over a range of flows from very low to five times normal

  15. Iodophenylpentadecanoic acid-myocardial blood flow relationship during maximal exercise with coronary occlusion.

    Science.gov (United States)

    Caldwell, J H; Martin, G V; Link, J M; Krohn, K A; Bassingthwaighte, J B

    1990-01-01

    Imaging 123I-labeled iodophenylpentadecanoic acid (IPPA) uptake and clearance from the myocardium following exercise has been advocated as a means of detecting myocardial ischemia because fatty acid deposition is enhanced and clearance prolonged in regions of low flow. However, normal regional myocardial blood flows are markedly heterogeneous, and it is not known how this heterogeneity affects regional metabolism or substrate uptake and thus image interpretation. In five instrumented dogs running at near maximal workload on a treadmill, 131I-labeled IPPA and 15-micron 46Sc microspheres were injected into the left atrium after 30 sec of circumflex coronary artery occlusion. Microsphere and IPPA activity were determined in 250 mapped pieces of myocardium of approximately 400 mg. Myocardial blood flows (from microspheres) ranged from 0.05 to 7.6 ml/min/g. Deposition of IPPA was proportional to regional flows (r = 0.83) with an average retention of 25%. The mean endocardial-epicardial ratio for IPPA (0.90 +/- 0.43) was similar to that for microspheres (0.94 +/- 0.47; p = 0.08). Thus, initial IPPA deposition during treadmill exercise increases in proportion to regional myocardial blood flow over a range of flows from very low to five times normal.

  16. Novel monorail infusion catheter for volumetric coronary blood flow measurement in humans: in vitro validation

    NARCIS (Netherlands)

    van 't Veer, M.; Adjedj, J.; Wijnbergen, I.; Tóth, G.G.; Rutten, M.C.M.; Barbato, E.; van Nunen, L.X.; Pijls, N.H.J.; de Bruyne, B.

    2016-01-01

    AIMS: The aim of this study is to validate a novel monorail infusion catheter for thermodilution-based quantitative coronary flow measurements. METHODS AND RESULTS: Based on the principles of thermodilution, volumetric coronary flow can be determined from the flow rate of a continuous saline

  17. Patient Specific Multiscale Simulations of Blood Flow in Coronary Artery Bypass Surgery

    Science.gov (United States)

    Bangalore Ramachandra, Abhay; Sankaran, Sethuraman; Kahn, Andrew M.; Marsden, Alison L.

    2013-11-01

    Coronary artery bypass surgery is performed to revascularize blocked coronary arteries in roughly 400,000 patients per year in the US.While arterial grafts offer superior patency, vein grafts are used in more than 70% of procedures, as most patients require multiple grafts. Vein graft failure (approx. 50% within 10 years) remains a major clinical issue. Mounting evidence suggests that hemodynamics plays a key role as a mechano-biological stimulus contributing to graft failure. However, quantifying relevant hemodynamic quantities (e.g. wall shear stress) invivo is not possible directly using clinical imaging techniques. We numerically compute graft hemodynamics in a cohort of 3-D patient specific models using a stabilized finite element method. The 3D flow domain is coupled to a 0D lumped parameter circulatory model. Boundary conditions are tuned to match patient specific blood pressures, stroke volumes & heart rates. Results reproduce clinically observed coronary flow waveforms. We quantify differences in multiple hemodynamic quantities between arterial & venous grafts & discuss possible correlations between graft hemodynamics & clinically observed graft failure.Such correlations will provide further insight into mechanisms of graft failure and may lead to improved clinical outcomes.

  18. Effects of coil closure of patent ductus arteriosus on left anterior descending coronary artery blood flow using transthoracic Doppler echocardiography.

    Science.gov (United States)

    Harada, Kenji; Toyono, Manotomo; Tamura, Masamichi

    2004-06-01

    Transthoracic Doppler echocardiography provides noninvasive measurements of coronary blood flow in the left anterior descending coronary artery (LAD). This method has the potential to show the effects of acute changes in loading conditions on blood flow. Coil closure of patent ductus arteriosus (PDA) is a model of acute changes in blood pressure and left ventricular (LV) preload that influences coronary blood flow. We applied this technique to assess the coronary blood flow changes for patients with PDA before and immediately after PDA coil closure. We examined 9 patients (1.8 +/- 1.1 years) with simple PDA and 8 age-matched healthy children. LV dimensions and LV mass were measured. Maximum peak flow velocity and flow volume in the LAD were measured. Pulmonary to systemic flow ratios (Qp/Qs) were obtained by cardiac catheterization. After PDA coil closure, LV end-diastolic dimension decreased, and systolic and diastolic blood pressures increased significantly. The maximum peak flow velocity, LAD flow volume, and the ratio of LAD flow volume to LV mass increased significantly. The changes in maximum peak flow velocity and the ratio of LAD flow volume to LV mass (F/M) correlated positively with the changes in diastolic pressure and Qp/Qs. In 5 patients who had Qp/Qs > 1.5, the mean F/M was significantly lower compared with control subjects, but they increased to normal values after coil closure of PDA. PDA coil closure increases diastolic pressure and decreases Qp/Qs, resulting in improvement of myocardial perfusion. These findings provide new insights into the relationship between cardiac function and coronary circulation in pediatric patients with heart diseases associated with PDA.

  19. A mathematical model of coronary blood flow control: simulation of patient-specific three-dimensional hemodynamics during exercise

    Science.gov (United States)

    Lau, Kevin D.; Asrress, Kaleab N.; Redwood, Simon R.; Figueroa, C. Alberto

    2016-01-01

    This work presents a mathematical model of the metabolic feedback and adrenergic feedforward control of coronary blood flow that occur during variations in the cardiac workload. It is based on the physiological observations that coronary blood flow closely follows myocardial oxygen demand, that myocardial oxygen debts are repaid, and that control oscillations occur when the system is perturbed and so are phenomenological in nature. Using clinical data, we demonstrate that the model can provide patient-specific estimates of coronary blood flow changes between rest and exercise, requiring only the patient's heart rate and peak aortic pressure as input. The model can be used in zero-dimensional lumped parameter network studies or as a boundary condition for three-dimensional multidomain Navier-Stokes blood flow simulations. For the first time, this model provides feedback control of the coronary vascular resistance, which can be used to enhance the physiological accuracy of any hemodynamic simulation, which includes both a heart model and coronary arteries. This has particular relevance to patient-specific simulation for which heart rate and aortic pressure recordings are available. In addition to providing a simulation tool, under our assumptions, the derivation of our model shows that β-feedforward control of the coronary microvascular resistance is a mathematical necessity and that the metabolic feedback control must be dependent on two error signals: the historical myocardial oxygen debt, and the instantaneous myocardial oxygen deficit. PMID:26945076

  20. A mathematical model of coronary blood flow control: simulation of patient-specific three-dimensional hemodynamics during exercise.

    Science.gov (United States)

    Arthurs, Christopher J; Lau, Kevin D; Asrress, Kaleab N; Redwood, Simon R; Figueroa, C Alberto

    2016-05-01

    This work presents a mathematical model of the metabolic feedback and adrenergic feedforward control of coronary blood flow that occur during variations in the cardiac workload. It is based on the physiological observations that coronary blood flow closely follows myocardial oxygen demand, that myocardial oxygen debts are repaid, and that control oscillations occur when the system is perturbed and so are phenomenological in nature. Using clinical data, we demonstrate that the model can provide patient-specific estimates of coronary blood flow changes between rest and exercise, requiring only the patient's heart rate and peak aortic pressure as input. The model can be used in zero-dimensional lumped parameter network studies or as a boundary condition for three-dimensional multidomain Navier-Stokes blood flow simulations. For the first time, this model provides feedback control of the coronary vascular resistance, which can be used to enhance the physiological accuracy of any hemodynamic simulation, which includes both a heart model and coronary arteries. This has particular relevance to patient-specific simulation for which heart rate and aortic pressure recordings are available. In addition to providing a simulation tool, under our assumptions, the derivation of our model shows that β-feedforward control of the coronary microvascular resistance is a mathematical necessity and that the metabolic feedback control must be dependent on two error signals: the historical myocardial oxygen debt, and the instantaneous myocardial oxygen deficit. Copyright © 2016 the American Physiological Society.

  1. Catheter-Based Measurements of Absolute Coronary Blood Flow and Microvascular Resistance: Feasibility, Safety, and Reproducibility in Humans.

    Science.gov (United States)

    Xaplanteris, Panagiotis; Fournier, Stephane; Keulards, Daniëlle C J; Adjedj, Julien; Ciccarelli, Giovanni; Milkas, Anastasios; Pellicano, Mariano; Van't Veer, Marcel; Barbato, Emanuele; Pijls, Nico H J; De Bruyne, Bernard

    2018-03-01

    The principle of continuous thermodilution can be used to calculate absolute coronary blood flow and microvascular resistance (R). The aim of the study is to explore the safety, feasibility, and reproducibility of coronary blood flow and R measurements as measured by continuous thermodilution in humans. Absolute coronary flow and R can be calculated by thermodilution by infusing saline at room temperature through a dedicated monorail catheter. The temperature of saline as it enters the vessel, the temperature of blood and saline mixed in the distal part of the vessel, and the distal coronary pressure were measured by a pressure/temperature sensor-tipped guidewire. The feasibility and safety of the method were tested in 135 patients who were referred for coronary angiography. No significant adverse events were observed; in 11 (8.1%) patients, bradycardia and concomitant atrioventricular block appeared transiently and were reversed immediately on interruption of the infusion. The reproducibility of measurements was tested in a subgroup of 80 patients (129 arteries). Duplicate measurements had a strong correlation both for coronary blood flow (ρ=0.841, P <0.001; intraclass correlation coefficient=0.89, P <0.001) and R (ρ=0.780, P <0.001; intraclass correlation coefficient=0.89, P <0.001). In Bland-Altman plots, there was no significant bias or asymmetry. Absolute coronary blood flow (in L/min) and R (in mm Hg/L/min or Wood units) can be safely and reproducibly measured with continuous thermodilution. This approach constitutes a new opportunity for the study of the coronary microcirculation. © 2018 American Heart Association, Inc.

  2. Changes in myocardial blood flow and S-T segment elevation following coronary artery occlusion in dogs

    International Nuclear Information System (INIS)

    Smith, H.J.; Singh, B.N.; Norris, R.M.; John, M.B.; Hurley, P.J.

    1975-01-01

    The relationship between regional blood flow and epicardial S-T segment elevation was studied in 26 open-chest anesthetized dogs with left anterior coronary artery ligations. Changes in myocardial blood flow, measured with 15 +- 5 μ (diameter) microspheres labeled with 141 Ce, 85 Sr, and 169 Yb, were correlated with summated S-T segment elevations 15 minutes, 1 hour, and 2 hours after coronary artery occlusion. In normal areas, myocardial blood flow was 113 +- 5 ml/min 100 g -1 and summated S-T segment elevation was 0.3 +- 0.2 mv. Fifteen minutes after coronary artery occlusion in 26 dogs, S-T segment elevation was 5.7 +- 0.7 mv over the center of the infarct and myocardial blood flow was 10 +- 1 ml/min 100 g -1 ; over the border zone, myocardial blood flow was 63 +- 4 ml/min 100 g -1 and S-T segment elevation was 3.1 +- 0.1 mv. One third of the areas with a myocardial blood flow of 10 ml/min 100 g -1 or less had no S-T segment elevation. In the center and border zones of the infarct in 9 dogs, myocardial blood flow increased from 11 +- 2 and 67 +- 8 ml/min 100 g -1 15 minutes after occlusion to 20 +- 4 and 84 +- 12 ml/min 100 g -1 , respectively, 2 hours after coronary artery occlusion. These increases were not associated with a significant reduction in summated S-T segment elevation. The results do not suggest a simple quantitative relationship between epicardial S-T segment elevation and myocardial blood flow following acute coronary artery occlusion

  3. Continuous determination of regional myocardial blood flow with intracoronary krypton-81m in coronary artery disease

    International Nuclear Information System (INIS)

    Remme, W.J.; Krauss, X.H.; van Hoogenhuyze, D.C.; Cox, P.H.; Storm, C.J.; Kruyssen, D.A.

    1985-01-01

    Pacing-induced changes in regional coronary flow were studied continuously with krypton-81m by intracoronary infusion in 25 patients: 21 with 50% or greater diameter narrowing of 1 or more left coronary arteries (group I) and 4 with less than 50% diameter reduction of a left coronary artery (group II). No changes occurred in group II. In group I, krypton-81m perfusion decreased progressively in all areas with more than 70% diameter narrowing, with a simultaneous increase in normal regions. At the end of pacing during angina, krypton-81m perfusion was reduced to 81 +/- 4% of control in areas with 71 to 90% diameter reduction (n = 8) and to 69 +/- 6% in areas with more than 90% diameter narrowing (n = 15). In contrast, in regions with 50 to 70% diameter reduction changes were variable (decrease in 4 regions, increase in 2 and an unchanged distribution in 1 region). Krypton-81m perfusion decreased early, before general signs of ischemia in areas with more than 90% diameter reduction, whereas this decrease occurred later in regions with 71 to 90% diameter narrowing, concurrently with ST-segment changes but before anginal pain. Although all signs of ischemia had disappeared between 2 and 5 minutes after pacing, changes in krypton-81m distribution persisted in most areas for 5 to 15 minutes after pacing. It is concluded that the functional significance of coronary arterial narrowing can be assessed with a continuous intracoronary infusion of krypton-81m. Changes in regional distribution persisted after cessation of pacing-induced ischemia, indicating an ongoing decrease in regional myocardial blood flow

  4. Effect of intra-aortic balloon pump on coronary blood flow during different balloon cycles support: A computer study.

    Science.gov (United States)

    Aye, Thin Pa Pa; Htet, Zwe Lin; Singhavilai, Thamvarit; Naiyanetr, Phornphop

    2015-01-01

    Intra-aortic balloon pump (IABP) has been used in clinical treatment as a mechanical circulatory support device for patients with heart failure. A computer model is used to study the effect on coronary blood flow (CBF) with different balloon cycles under both normal and pathological conditions. The model of cardiovascular and IABP is developed by using MATLAB SIMULINK. The effect on coronary blood flow has been studied under both normal and pathological conditions using different balloon cycles (balloon off; 1:4; 1:2; 1:1). A pathological heart is implemented by reducing the left ventricular contractility. The result of this study shows that the rate of balloon cycles is related to the level of coronary blood flow.

  5. Virtual Resting Pd/Pa From Coronary Angiography and Blood Flow Modelling: Diagnostic Performance Against Fractional Flow Reserve.

    Science.gov (United States)

    Papafaklis, Michail I; Muramatsu, Takashi; Ishibashi, Yuki; Bourantas, Christos V; Fotiadis, Dimitrios I; Brilakis, Emmanouil S; Garcia-Garcia, Héctor M; Escaned, Javier; Serruys, Patrick W; Michalis, Lampros K

    2018-03-01

    Fractional flow reserve (FFR) has been established as a useful diagnostic tool. The distal coronary pressure to aortic pressure (Pd/Pa) ratio at rest is a simpler physiologic index but also requires the use of the pressure wire, whereas recently proposed virtual functional indices derived from coronary imaging require complex blood flow modelling and/or are time-consuming. Our aim was to test the diagnostic performance of virtual resting Pd/Pa using routine angiographic images and a simple flow model. Three-dimensional quantitative coronary angiography (3D-QCA) was performed in 139 vessels (120 patients) with intermediate lesions assessed by FFR. The resting Pd/Pa for each lesion was assessed by computational fluid dynamics. The discriminatory power of virtual resting Pd/Pa against FFR (reference: ≤0.80) was high (area under the receiver operator characteristic curve [AUC]: 90.5% [95% CI: 85.4-95.6%]). Diagnostic accuracy, sensitivity and specificity for the optimal virtual resting Pd/Pa cut-off (≤0.94) were 84.9%, 90.4% and 81.6%, respectively. Virtual resting Pd/Pa demonstrated superior performance (pvirtual resting Pd/Pa and FFR (r=0.69, pVirtual resting Pd/Pa using routine angiographic data and a simple flow model provides fast functional assessment of coronary lesions without requiring the pressure-wire and hyperaemia induction. The high diagnostic performance of virtual resting Pd/Pa for predicting FFR shows promise for using this simple/fast virtual index in clinical practice. Copyright © 2017 Australian and New Zealand Society of Cardiac and Thoracic Surgeons (ANZSCTS) and the Cardiac Society of Australia and New Zealand (CSANZ). Published by Elsevier B.V. All rights reserved.

  6. Relationship between segmental thallium-201 uptake and regional myocardial blood flow in patients with coronary artery disease

    International Nuclear Information System (INIS)

    Nichols, A.B.; Weiss, M.B.; Sciacca, R.R.; Cannon, P.J.; Blood, D.K.

    1983-01-01

    The relationship between the spatial distribution of thallium-201 in myocardial perfusion scintigrams and the distribution of left ventricular regional myocardial blood flow was examined in 25 patients undergoing coronary arteriography. Thallium-201 myocardial scintigrams were obtained after symptom-limited exercise and after a 4 hr delay. Regional myocardial blood flow was measured by the xenon-133 clearance method in patients at rest and during rapid atrial pacing to a double product comparable with that achieved during exercise stress testing. Patterns of regional thallium-201 activity and regional myocardial blood flow, recorded in similar left anterior oblique projections, were compared for left ventricular segments supplied by the left anterior descending (LAD) and left circumflex (CIRC) arteries. In 11 patients without significant lesions of the left coronary artery (group 1), thallium-201 was homogeneously distributed in the LAD and CIRC distributions in scintigrams taken during peak exercise; these scintigrams correspond to homogeneous regional myocardial blood flow in the LAD and CIRC regions during pacing-induced stress. In 14 patients with significant lesions of the left coronary artery (group 2), ratios of regional thallium-201 activity in the LAD and CIRC distributions of exercise scintigrams correlated well (r . .84) with ratios of regional myocardial blood flow measured during rapid pacing. Background subtraction altered the relationship between relative thallium-201 uptake and regional myocardial blood flow, causing overestimation of the magnitude of flow reduction on exercise scintigrams

  7. Change in coronary blood flow after percutaneous coronary intervention in relation to baseline lesion physiology: results of the JUSTIFY-PCI study.

    Science.gov (United States)

    Nijjer, Sukhjinder S; Petraco, Ricardo; van de Hoef, Tim P; Sen, Sayan; van Lavieren, Martijn A; Foale, Rodney A; Meuwissen, Martijn; Broyd, Christopher; Echavarria-Pinto, Mauro; Al-Lamee, Rasha; Foin, Nicolas; Sethi, Amarjit; Malik, Iqbal S; Mikhail, Ghada W; Hughes, Alun D; Mayet, Jamil; Francis, Darrel P; Di Mario, Carlo; Escaned, Javier; Piek, Jan J; Davies, Justin E

    2015-06-01

    Percutaneous coronary intervention (PCI) aims to increase coronary blood flow by relieving epicardial obstruction. However, no study has objectively confirmed this and assessed changes in flow over different phases of the cardiac cycle. We quantified the change in resting and hyperemic flow velocity after PCI in stenoses defined physiologically by fractional flow reserve and other parameters. Seventy-five stenoses (67 patients) underwent paired flow velocity assessment before and after PCI. Flow velocity was measured over the whole cardiac cycle and the wave-free period. Mean fractional flow reserve was 0.68±0.02. Pre-PCI, hyperemic flow velocity is diminished in stenoses classed as physiologically significant compared with those classed nonsignificant (PPCI, resting flow velocity over the wave-free period increased little (5.6±1.6 cm/s) and significantly less than hyperemic flow velocity (21.2±3 cm/s; P0.80 had a significantly smaller gain (Δ4.6±2.3 cm/s; PPCI physiology is strongly associated with post-PCI increase in hyperemic coronary flow velocity. Hyperemic flow velocity increases 6-fold more when stenoses classed as physiologically significant undergo PCI than when nonsignificant stenoses are treated. Resting flow velocity measured over the wave-free period changes at least 4-fold less than hyperemic flow velocity after PCI. © 2015 American Heart Association, Inc.

  8. Change in Coronary Blood Flow After Percutaneous Coronary Intervention in Relation to Baseline Lesion Physiology Results of the JUSTIFY-PCI Study

    Science.gov (United States)

    Nijjer, Sukhjinder S.; Petraco, Ricardo; van de Hoef, Tim P.; Sen, Sayan; van Lavieren, Martijn A.; Foale, Rodney A.; Meuwissen, Martijn; Broyd, Christopher; Echavarria-Pinto, Mauro; Al-Lamee, Rasha; Foin, Nicolas; Sethi, Amarjit; Malik, Iqbal S.; Mikhail, Ghada W.; Hughes, Alun D.; Mayet, Jamil; Francis, Darrel P.; Di Mario, Carlo; Escaned, Javier; Piek, Jan J.; Davies, Justin E.

    2016-01-01

    Background Percutaneous coronary intervention (PCI) aims to increase coronary blood flow by relieving epicardial obstruction. However, no study has objectively confirmed this and assessed changes in flow over different phases of the cardiac cycle. We quantified the change in resting and hyperemic flow velocity after PCI in stenoses defined physiologically by fractional flow reserve and other parameters. Methods and Results Seventy-five stenoses (67 patients) underwent paired flow velocity assessment before and after PCI. Flow velocity was measured over the whole cardiac cycle and the wave-free period. Mean fractional flow reserve was 0.68±0.02. Pre-PCI, hyperemic flow velocity is diminished in stenoses classed as physiologically significant compared with those classed nonsignificant (PPCI, resting flow velocity over the wave-free period increased little (5.6±1.6 cm/s) and significantly less than hyperemic flow velocity (21.2±3 cm/s; P0.80 had a significantly smaller gain (Δ4.6±2.3 cm/s; PPCI physiology is strongly associated with post-PCI increase in hyperemic coronary flow velocity. Hyperemic flow velocity increases 6-fold more when stenoses classed as physiologically significant undergo PCI than when nonsignificant stenoses are treated. Resting flow velocity measured over the wave-free period changes at least 4-fold less than hyperemic flow velocity after PCI. PMID:26025217

  9. Myocardial blood flow reserve is impaired in patients with aortic valve calcification and unobstructed epicardial coronary arteries.

    Science.gov (United States)

    Nel, Karen; Nam, Michael C Y; Anstey, Chris; Boos, Christopher J; Carlton, Edward; Senior, Roxy; Kaski, Juan Carlos; Khattab, Ahmed; Shamley, Delva; Byrne, Christopher D; Stanton, Tony; Greaves, Kim

    2017-12-01

    Although calcific aortic valve disease (CAVD) is associated with coronary atherosclerosis, it is not known whether early CAVD is associated with coronary microcirculatory dysfunction (CMD). We sought to investigate the relationship between myocardial blood flow reserve (MBFR) - a measure of CMD, and early CAVD in the absence of obstructive epicardial coronary artery disease. We also determined whether this relationship was independent of coronary artery disease (CAD) and hs-CRP, a marker of systemic inflammation. 183 patients with chest pain and unobstructed coronary arteries were studied. Aortic valve calcification score (AVCS), coronary total plaque length (TPL), and coronary calcium score were quantified from multislice CT. MBFR was assessed using vasodilator myocardial contrast echocardiography. Hs-CRP was measured from venous blood using a particle-enhanced immunoassay. Mean (±SD) participant age was 59.8 (9.6) years. Mean AVCS was 68 (258) AU, TPL was 15.6 (22.2) mm, and median coronary calcification score was 43.5AU. Mean MBFR was 2.20 (0.52). Mean hs-CRP was 2.52 (3.86) mg/l. Multivariable linear regression modelling incorporating demographics, coronary plaque characteristics, MBFR, and inflammatory markers, demonstrated that age (β=0.05, 95% CI: 0.02, 0.08, P=0.007), hs-CRP (β=0.09, CI: 0.02, 0.16, P=0.010) and diabetes (β=1.03, CI: 0.08, 1.98, P=0.033), were positively associated with AVCS. MBFR (β=-0.87, CI: -1.44, -0.30, P=0.003), BMI (β=-0.11, CI: -0.21, -0.01, P=0.033), and LDL (β=-0.32, CI: -0.61, -0.03, P=0.029) were negatively associated with AVCS. TPL and coronary calcium score were not independently associated with AVCS when included in the regression model. Coronary microvascular function as determined by measurement of myocardial blood flow reserve is independently associated with early CAVD. This effect is independent of the presence of coronary artery disease and also systemic inflammation. Copyright © 2017 Elsevier B.V. All rights

  10. Measurement of the blood flow rate and velocity in coronary artery stenosis using intracoronary frequency domain optical coherence tomography: Validation against fractional flow reserve.

    Science.gov (United States)

    Zafar, Haroon; Sharif, Faisal; Leahy, Martin J

    2014-12-01

    The main objective of this study was to assess the blood flow rate and velocity in coronary artery stenosis using intracoronary frequency domain optical coherence tomography (FD-OCT). A correlation between fractional flow reserve (FFR) and FD-OCT derived blood flow velocity is also included in this study. A total of 20 coronary stenoses in 15 patients were assessed consecutively by quantitative coronary angiography (QCA), FFR and FD-OCT. A percutaneous coronary intervention (PCI) optimization system was used in this study which combines wireless FFR measurement and FD-OCT imaging in one platform. Stenoses were labelled severe if FFR ≤ 0.8. Blood flow rate and velocity in each stenosis segment were derived from the volumetric analysis of the FD-OCT pull back images. The FFR value was ≤ 0.80 in 5 stenoses (25%). The mean blood flow rate in severe coronary stenosis ( n  = 5) was 2.54 ± 0.55 ml/s as compared to 4.81 ± 1.95 ml/s in stenosis with FFR > 0.8 ( n  = 15). A good and significant correlation between FFR and FD-OCT blood flow velocity in coronary artery stenosis ( r  = 0.74, p  < 0.001) was found. The assessment of stenosis severity using FD-OCT derived blood flow rate and velocity has the ability to overcome many limitations of QCA and intravascular ultrasound (IVUS).

  11. Beta-1 vs. beta-2 adrenergic control of coronary blood flow during isometric handgrip exercise in humans.

    Science.gov (United States)

    Maman, Stephan R; Vargas, Alvaro F; Ahmad, Tariq Ali; Miller, Amanda J; Gao, Zhaohui; Leuenberger, Urs A; Proctor, David N; Muller, Matthew D

    2017-08-01

    During exercise, β-adrenergic receptors are activated throughout the body. In healthy humans, the net effect of β-adrenergic stimulation is an increase in coronary blood flow. However, the role of vascular β1 vs. β2 receptors in coronary exercise hyperemia is not clear. In this study, we simultaneously measured noninvasive indexes of myocardial oxygen supply (i.e., blood velocity in the left anterior descending coronary artery; Doppler echocardiography) and demand [i.e., rate pressure product (RPP) = heart rate × systolic blood pressure) and tested the hypothesis that β1 blockade with esmolol improves coronary exercise hyperemia compared with nonselective β-blockade with propranolol. Eight healthy young men received intravenous infusions of esmolol, propranolol, and saline on three separate days in a single-blind, randomized, crossover design. During each infusion, subjects performed isometric handgrip exercise until fatigue. Blood pressure, heart rate, and coronary blood velocity (CBV) were measured continuously, and RPP was calculated. Changes in parameters from baseline were compared with paired t -tests. Esmolol (Δ = 3296 ± 1204) and propranolol (Δ = 2997 ± 699) caused similar reductions in peak RPP compared with saline (Δ = 5384 ± 1865). In support of our hypothesis, ΔCBV with esmolol was significantly greater than with propranolol (7.3 ± 2.4 vs. 4.5 ± 1.6 cm/s; P = 0.002). This effect was also evident when normalizing ΔCBV to ΔRPP. In summary, not only does selective β1 blockade reduce myocardial oxygen demand during exercise, but it also unveils β2-receptor-mediated coronary exercise hyperemia. NEW & NOTEWORTHY In this study, we evaluated the role of vascular β1 vs. β2 receptors in coronary exercise hyperemia in a single-blind, randomized, crossover study in healthy men. In response to isometric handgrip exercise, blood flow velocity in the left anterior descending coronary artery was significantly greater with esmolol compared with

  12. 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

  13. Coronary blood flow and thallium 201 uptake in rejecting rat heart transplantations

    International Nuclear Information System (INIS)

    Bergsland, J.; Hwang, K.; Driscoll, R.; Carr, E.A.; Wright, J.R.; Curran-Everett, D.C.; Carroll, M.; Krasney, E.; Krasney, J.A.

    1989-01-01

    The effects of rejection on coronary flow (CAF) in heart allografts are unclear, although previous evidence with cardiac imaging agents indicates impaired flow during advanced rejection. The purpose of this study was to measure CAF in heterotopically placed heart grafts. Lewis rats (LEW) received grafts from either syngeneic Lewis rats (LEW/LEW group) or allogeneic ACI rats (ACI/LEW group). CAF was measured in both the transplanted and native hearts with radiolabeled microspheres. Rejection was measured histologically (grades 0 [absent] to 4+ [severe]). In addition systemic blood pressure and cardiac outputs of the native hearts were determined with microspheres. Different animals were studied during relatively early (4 days) and late (6 days) rejection. Among the 4-day animals a cyclosporine-treated group was included (ACI/LEW CyA). In 6-day rats CAF in allografts was lower (0.56 +/- .06 ml/gm/min) compared with syngeneic grafts (1.72 +/- 0.4 ml/gm/min) (p less than 0.05). The CAF in the native hearts did not differ significantly but was higher than in the grafts in both groups. Heart rates were reduced in allografts (p less than 0.05). It is interesting that arterial pressure and cardiac output were significantly lower in animals bearing allogeneic than syngeneic grafts. In rats studied at 4 days graft CAF was lower than in the native heart in both the LEW/LEW and ACI/LEW groups, but there was no significant difference in behavior between groups. The same was true for a cyclosporine-treated group. Graft heart rates were similar in all 4-day rats

  14. Complete blood cell count components and coronary slow-flow phenomenon

    Directory of Open Access Journals (Sweden)

    Arjmand N

    2016-12-01

    Full Text Available Nasim Arjmand, Mohammad Reza Dehghani Department of Cardiology, Seyyed-al-Shohada Heart Center, Urmia University of Medical Sciences, Urmia, IranDespite the implementation of preventive strategies, ischemic heart disease and stroke remain the main causes of mortality and morbidity worldwide.1,2 Of the cardiovascular diseases, coronary slow-flow phenomenon (CSFP, with a prevalence rate of 1%–7% among patients undergoing diagnostic coronary angiography, has been found to be associated with cardiovascular events, including cardiac arrhythmia and acute coronary syndrome.3–5 However, the potential mechanisms involved in the pathogenesis of CSFP remain unknown. Microvascular and endothelial dysfunctions, inflammation, diffuse atherosclerosis, and increased platelet aggregability have been reported to be the main possible etiologies for CSFP.6,7View original paper by Atlas and colleagues.

  15. Differential effects of androgens on coronary blood flow regulation and arteriolar diameter in intact and castrated swine

    Directory of Open Access Journals (Sweden)

    O’Connor Erin K

    2012-05-01

    Full Text Available Abstract Background Low endogenous testosterone levels have been shown to be a risk factor for the development of cardiovascular disease and cardiovascular benefits associated with testosterone replacement therapy are being advocated; however, the effects of endogenous testosterone levels on acute coronary vasomotor responses to androgen administration are not clear. The objective of this study was to compare the effects of acute androgen administration on in vivo coronary conductance and in vitro coronary microvascular diameter in intact and castrated male swine. Methods Pigs received intracoronary infusions of physiologic levels (1–100 nM of testosterone, the metabolite 5α-dihydrotestosterone, and the epimer epitestosterone while left anterior descending coronary blood flow and mean arterial pressure were continuously monitored. Following sacrifice, coronary arterioles were isolated, cannulated, and exposed to physiologic concentrations (1–100 nM of testosterone, 5α-dihydrotestosterone, and epitestosterone. To evaluate effects of the androgen receptor on acute androgen dilation responses, real-time PCR and immunohistochemistry for androgen receptor were performed on conduit and resistance coronary vessels. Results In vivo, testosterone and 5α-dihydrotestosterone produced greater increases in coronary conductance in the intact compared to the castrated males. In vitro, percent maximal dilation of microvessels was similar between intact and castrated males for testosterone and 5α-dihydrotestosterone. In both studies epitestosterone produced significant increases in conductance and microvessel diameter from baseline in the intact males. Androgen receptor mRNA expression and immunohistochemical staining were similar in intact and castrated males. Conclusions Acute coronary vascular responses to exogenous androgen administration are increased by endogenous testosterone, an effect unrelated to changes in androgen receptor expression.

  16. Quantitative relationship between coronary artery calcium and myocardial blood flow by hybrid rubidium-82 PET/CT imaging in patients with suspected coronary artery disease.

    Science.gov (United States)

    Assante, Roberta; Zampella, Emilia; Arumugam, Parthiban; Acampa, Wanda; Imbriaco, Massimo; Tout, Deborah; Petretta, Mario; Tonge, Christine; Cuocolo, Alberto

    2017-04-01

    We assessed the relationship between coronary artery calcium (CAC) score, myocardial blood flow (MBF) and coronary flow reserve (CFR) in patients undergoing hybrid 82 Rb positron emission tomography (PET)/computed tomography (CT) imaging for suspected CAD. We also evaluated if CAC score is able to predict a reduced CFR independently from conventional coronary risk factors. A total of 637 (mean age 58 ± 13 years) consecutive patients were studied. CAC score was measured according to the Agatston method and patients were categorized into 4 groups (0, 0.01-99.9, 100-399.9, and ≥400). Baseline and hyperemic MBF were automatically quantified. CFR was calculated as the ratio of hyperemic to baseline MBF and it was considered reduced when <2. Global CAC score showed a significant inverse correlation with hyperemic MBF and CFR (both P < .001), while no correlation between CAC score and baseline MBF was found. At multivariable logistic regression analysis age, diabetes and CAC score were independently associated with reduced CFR (all P < .001). The addition of CAC score to clinical data increased the global chi-square value for predicting reduced CFR from 81.01 to 91.13 (P < .01). Continuous net reclassification improvement, obtained by adding CAC score to clinical data, was 0.36. CAC score provides incremental information about coronary vascular function over established CAD risk factors in patients with suspected CAD and it might be helpful for identifying those with a reduced CFR.

  17. 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.)

  18. 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

  19. 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

  20. 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

  1. Myocardial blood flow quantification for evaluation of coronary artery disease by positron emission tomography, cardiac magnetic resonance imaging, and computed tomography.

    Science.gov (United States)

    Waller, Alfonso H; Blankstein, Ron; Kwong, Raymond Y; Di Carli, Marcelo F

    2014-05-01

    The noninvasive detection of the presence and functional significance of coronary artery stenosis is important in the diagnosis, risk assessment, and management of patients with known or suspected coronary artery disease. Quantitative assessment of myocardial perfusion can provide an objective and reproducible estimate of myocardial ischemia and risk prediction. Positron emission tomography, cardiac magnetic resonance, and cardiac computed tomography perfusion are modalities capable of measuring myocardial blood flow and coronary flow reserve. In this review, we will discuss the technical aspects of quantitative myocardial perfusion imaging with positron emission tomography, cardiac magnetic resonance imaging, and computed tomography, and its emerging clinical applications.

  2. Impact of Admission Blood Glucose on Coronary Collateral Flow in Patients with ST-Elevation Myocardial Infarction.

    Science.gov (United States)

    Kurmus, Ozge; Aslan, Turgay; Ekici, Berkay; Baglan Uzunget, Sezen; Karaarslan, Sukru; Tanindi, Asli; Erkan, Aycan Fahri; Akgul Ercan, Ebru; Kervancıoglu, Celal

    2018-01-01

    In patients with acute myocardial infarction, glucose metabolism is altered and acute hyperglycemia on admission is common regardless of diabetes status. The development of coronary collateral is heterogeneous among individuals with coronary artery disease. In this study, we aimed to investigate whether glucose value on admission is associated with collateral flow in ST-elevation myocardial infarction (STEMI) patients. We retrospectively evaluated 190 consecutive patients with a diagnosis of first STEMI within 12 hours of onset of chest pain. Coronary collateral development was graded according to Rentrop classification. Rentrop 0-1 was graded as poor collateral development, and Rentrop 2-3 was graded as good collateral development. Admission glucose was measured and compared between two groups. Mean admission glucose level was 173.0 ± 80.1 mg/dl in study population. Forty-five (23.7%) patients had good collateral development, and 145 (76.3%) patients had poor collateral development. There were no statistically significant differences in demographic characteristics between two groups. Three-vessel disease was more common in patients with good collateral development ( p =0.026). Mean admission glucose level was higher in patients with poor collateral than good collateral (180.6 ± 84.9 mg/dl versus 148.7 ± 56.6 mg/dl, resp., p =0.008). In univariate analysis, higher admission glucose was associated with poor collateral development, but multivariate logistic regression analysis revealed a borderline result (odds ratio 0.994, 95% CI 0.989-1.000, p =0.049). Our results suggest that elevated glucose on admission may have a role in the attenuation of coronary collateral blood flow in acute myocardial infarction. Further studies are needed to validate our results.

  3. Assessment of myocardial blood flow and coronary flow reserve with positron emission tomography in ischemic heart disease: current state and future directions.

    Science.gov (United States)

    Al Badarin, Firas; Aljizeeri, Ahmed; Almasoudi, Fatimah; Al-Mallah, Mouaz H

    2017-07-01

    Positron emission tomography (PET) is a versatile imaging technology that allows assessment of myocardial perfusion, both at a spatially relative scale and also in absolute terms, thereby enabling noninvasive evaluation of myocardial blood flow (MBF) and coronary flow reserve (CFR). Assessment of MBF using FDA-approved PET isotopes, such as 82 Rb and 13 N-ammonia, has been well validated, and several software packages are currently available, thereby allowing for MBF evaluation to be incorporated into routine workflow in contemporary nuclear laboratories. Incremental diagnostic and prognostic information provided with the knowledge of MBF has the potential for widespread applications. Improving the ability to identify the true burden of obstructive epicardial coronary stenoses and allowing for noninvasive assessment of coronary micro circulatory function can be achieved with MBF assessment. On the other hand, attenuated CFR has been shown to predict adverse cardiovascular prognosis in a variety of clinical settings and patient subgroups. With expanding applications of MBF, this tool promises to provide unique insight into the integrity of the entire coronary vascular bed beyond what is currently available with relative perfusion assessment. This review intends to provide an in-depth discussion of technical and clinical aspects of MBF assessment with PET as it relates to patients with ischemic heart disease.

  4. Integration of Quantitative Positron Emission Tomography Absolute Myocardial Blood Flow Measurements in the Clinical Management of Coronary Artery Disease.

    Science.gov (United States)

    Gewirtz, Henry; Dilsizian, Vasken

    2016-05-31

    In the >40 years since planar myocardial imaging with(43)K-potassium was introduced into clinical research and management of patients with coronary artery disease (CAD), diagnosis and treatment have undergone profound scientific and technological changes. One such innovation is the current state-of-the-art hardware and software for positron emission tomography myocardial perfusion imaging, which has advanced it from a strictly research-oriented modality to a clinically valuable tool. This review traces the evolving role of quantitative positron emission tomography measurements of myocardial blood flow in the evaluation and management of patients with CAD. It presents methodology, currently or soon to be available, that offers a paradigm shift in CAD management. Heretofore, radionuclide myocardial perfusion imaging has been primarily qualitative or at best semiquantitative in nature, assessing regional perfusion in relative terms. Thus, unlike so many facets of modern cardiovascular practice and CAD management, which depend, for example, on absolute values of key parameters such as arterial and left ventricular pressures, serum lipoprotein, and other biomarker levels, the absolute levels of rest and maximal myocardial blood flow have yet to be incorporated into routine clinical practice even in most positron emission tomography centers where the potential to do so exists. Accordingly, this review focuses on potential value added for improving clinical CAD practice by measuring the absolute level of rest and maximal myocardial blood flow. Physiological principles and imaging fundamentals necessary to understand how positron emission tomography makes robust, quantitative measurements of myocardial blood flow possible are highlighted. © 2016 American Heart Association, Inc.

  5. 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

  6. Distinct alterations in sublingual microcirculatory blood flow and hemoglobin oxygenation in on-pump and off-pump coronary artery bypass graft surgery

    NARCIS (Netherlands)

    Atasever, Bektaş; Boer, Christa; Goedhart, Peter; Biervliet, Jules; Seyffert, Jan; Speekenbrink, Ron; Schwarte, Lothar; de Mol, Bas; Ince, Can

    2011-01-01

    The authors hypothesized that cardiopulmonary bypass (CPB) (on-pump) is associated with more severe changes in the microcirculatory blood flow and tissue oxygenation as compared with off-pump coronary artery bypass surgery. An observational study. A university hospital and teaching hospital.

  7. Influence of model boundary conditions on blood flow patterns in a patient specific stenotic right coronary artery.

    Science.gov (United States)

    Liu, Biyue; Zheng, Jie; Bach, Richard; Tang, Dalin

    2015-01-01

    In literature, the effect of the inflow boundary condition was investigated by examining the impact of the waveform and the shape of the spatial profile of the inlet velocity on the cardiac hemodynamics. However, not much work has been reported on comparing the effect of the different combinations of the inlet/outlet boundary conditions on the quantification of the pressure field and flow distribution patterns in stenotic right coronary arteries. Non-Newtonian models were used to simulate blood flow in a patient-specific stenotic right coronary artery and investigate the influence of different boundary conditions on the phasic variation and the spatial distribution patterns of blood flow. The 3D geometry of a diseased artery segment was reconstructed from a series of IVUS slices. Five different combinations of the inlet and the outlet boundary conditions were tested and compared. The temporal distribution patterns and the magnitudes of the velocity, the wall shear stress (WSS), the pressure, the pressure drop (PD), and the spatial gradient of wall pressure (WPG) were different when boundary conditions were imposed using different pressure/velocity combinations at inlet/outlet. The maximum velocity magnitude in a cardiac cycle at the center of the inlet from models with imposed inlet pressure conditions was about 29% lower than that from models using fully developed inlet velocity data. Due to the fact that models with imposed pressure conditions led to blunt velocity profile, the maximum wall shear stress at inlet in a cardiac cycle from models with imposed inlet pressure conditions was about 29% higher than that from models with imposed inlet velocity boundary conditions. When the inlet boundary was imposed by a velocity waveform, the models with different outlet boundary conditions resulted in different temporal distribution patterns and magnitudes of the phasic variation of pressure. On the other hand, the type of different boundary conditions imposed at the

  8. Effects of respiratory alkalosis and acidosis on myocardial blood flow and metabolism in patients with coronary artery disease.

    Science.gov (United States)

    Kazmaier, S; Weyland, A; Buhre, W; Stephan, H; Rieke, H; Filoda, K; Sonntag, H

    1998-10-01

    Variation of the arterial carbon dioxide partial pressure (PaCO2) is not uncommon in anesthetic practice. However, little is known about the myocardial consequences of respiratory alkalosis and acidosis, particularly in patients with coronary artery disease. The aim of the current study was to investigate the effects of variation in PaCO2 on myocardial blood flow (MBF), metabolism, and systemic hemodynamics in patients before elective coronary artery bypass graft surgery. In 10 male anesthetized patients, measurements of MBF, myocardial contractility, metabolism, and systemic hemodynamics were made in a randomized sequence at PaCO2 levels of 30, 40, and 50 mmHg, respectively. The MBF was measured using the Kety-Schmidt technique with argon as a tracer. End-diastolic left ventricular pressure and the maximal increase of left ventricular pressure were assessed using a manometer-tipped catheter. The cardiac index significantly changed with varying PaCO2 levels (hypocapnia, - 9%; hypercapnia, 13%). This reaction was associated with inverse changes in systemic vascular resistance index levels. The MBF significantly increased by 15% during hypercapnia, whereas no change was found during hypocapnia. Myocardial oxygen and glucose uptake and the maximal increase of left ventricular pressure were not affected by varying PaCO2 levels. In anesthetized patients with coronary artery disease, short-term variations in PaCO2 have significant effects on MBF but do not influence global myocardial oxygen and glucose uptake. Changes in systemic hemodynamics associated with respiratory alkalosis and acidosis are caused by changes in systemic vascular resistance rather than by alterations in myocardial contractility.

  9. Absolute coronary blood flow measurement and microvascular resistance in ST-elevation myocardial infarction in the acute and subacute phase

    Energy Technology Data Exchange (ETDEWEB)

    Wijnbergen, Inge; Veer, Marcel van ' t [Department of Cardiology, Catharina Hospital, Eindhoven (Netherlands); Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven (Netherlands); Lammers, Jeroen; Ubachs, Joey [Department of Cardiology, Catharina Hospital, Eindhoven (Netherlands); Pijls, Nico H.J., E-mail: nico.pijls@cze.nl [Department of Cardiology, Catharina Hospital, Eindhoven (Netherlands); Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven (Netherlands)

    2016-03-15

    Background/Purpose: In a number of patients with acute myocardial infarction (AMI), myocardial hypoperfusion, known as the no-reflow phenomenon, persists after primary percutaneous intervention (PPCI). The aim of this study was to evaluate the feasibility and safety of a new quantitative method of measuring absolute blood flow and resistance within the perfusion bed of an infarct-related artery. Furthermore, we sought to study no-reflow by correlating these measurements to the index of microvascular resistance (IMR) and the area at risk (AR) as determined by cardiac magnetic resonance imaging (CMR). Methods: Measurements of absolute flow and myocardial resistance were performed in 20 patients with ST-segment elevation myocardial infarction (STEMI), first immediately following PPCI and then again after 3–5 days. These measurements used the technique of thermodilution during a continuous infusion of saline. Flow was expressed in ml/min per gram of tissue within the area at risk. Results: The average time needed for measurement of absolute flow, resistance and IMR was 20 min, and all measurements could be performed without complication. A higher flow supplying the AR correlated with a lower IMR in the acute phase. Absolute flow increased from 3.14 to 3.68 ml/min/g (p = 0.25) and absolute resistance decreased from 1317 to 1099 dyne.sec.cm-5/g (p = 0.40) between the first day and fifth day after STEMI. Conclusions: Measurement of absolute flow and microvascular resistance is safe and feasible in STEMI patients and may allow for a better understanding of microvascular (dys)function in the early phase of AMI. - Highlights: • We measured absolute coronary blood flow and microvascular resistance in STEMI patients in the acute phase and in the subacute phase, using the technique of thermodilution with low grade intracoronary continuous infusion of saline. • These measurements are safe and feasible during PPCI in STEMI patients. • In STEMI patients, absolute flow

  10. 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)

  11. The effect of blood pressure on non-invasive fractional flow reserve derived from coronary computed tomography angiography

    Energy Technology Data Exchange (ETDEWEB)

    Kurata, Akira [Ehime University Graduate School of Medicine, Department of Radiology, Toon, Ehime (Japan); Erasmus University Medical Center, Department of Radiology, Rotterdam (Netherlands); Coenen, Adriaan; Lubbers, Marisa M.; Nieman, Koen [Erasmus University Medical Center, Department of Radiology, Rotterdam (Netherlands); Erasmus University Medical Center, Departmenet of Cardiology, Rotterdam (Netherlands); Kido, Teruhito; Mochizuki, Teruhito [Ehime University Graduate School of Medicine, Department of Radiology, Toon, Ehime (Japan); Kido, Tomoyuki [Matsuyama Saiseikai Hospital, Department of Radiology, Matsuyama, Ehime (Japan); Yamashita, Natsumi [Clinical Research Center, National Hospital Organization Shikoku Cancer Center, Division of Clinical Biostatistics, Section of Cancer Prevention and Epidemiology, Matsuyama, Ehime (Japan); Watanabe, Kouki [Matsuyama Saiseikai Hospital, Department of Cardiology, Matsuyama, Ehime (Japan); Krestin, Gabriel P. [Erasmus University Medical Center, Department of Radiology, Rotterdam (Netherlands)

    2017-04-15

    The aim of this study is to assess the effect of blood pressure (BP) on coronary computed tomography angiography (CTA) derived computational fractional flow reserve (CTA-FFR). Twenty-one patients who underwent coronary CTA and invasive FFR were retrospectively identified. Ischemia was defined as invasive FFR ≤0.80. Using a work-in-progress computational fluid dynamics algorithm, CTA-FFR was computed with BP measured before CTA, and simulated BPs of 60/50, 90/60, 110/70, 130/80, 150/90, and 180/100 mmHg respectively. Correlation between CTA-FFR and invasive FFR was assessed using Pearson test. The repeated measuring test was used for multiple comparisons of CTA-FFR values by simulated BP inputs. Twenty-nine vessels (14 with invasive FFR ≤0.80) were assessed. The average CTA-FFR for measured BP (134 ± 20/73 ± 12 mmHg) was 0.77 ± 0.12. Correlation between CTA-FFR by measured BP and invasive FFR was good (r = 0.735, P < 0.001). For simulated BPs of 60/50, 90/60, 110/70, 130/80, 150/90, and 180/100 mmHg, the CTA-FFR increased: 0.69 ± 0.13, 0.73 ± 0.12, 0.75 ± 0.12, 0.77 ± 0.11, 0.79 ± 0.11, and 0.81 ± 0.10 respectively (P < 0.05). Measurement of the BP just before CTA is preferred for accurate CTA-FFR simulation. BP variations in the common range slightly affect CTA-FFR. However, inaccurate BP assumptions differing from the patient-specific BP could cause misinterpretation of borderline significant lesions. (orig.)

  12. The effect of blood pressure on non-invasive fractional flow reserve derived from coronary computed tomography angiography

    International Nuclear Information System (INIS)

    Kurata, Akira; Coenen, Adriaan; Lubbers, Marisa M.; Nieman, Koen; Kido, Teruhito; Mochizuki, Teruhito; Kido, Tomoyuki; Yamashita, Natsumi; Watanabe, Kouki; Krestin, Gabriel P.

    2017-01-01

    The aim of this study is to assess the effect of blood pressure (BP) on coronary computed tomography angiography (CTA) derived computational fractional flow reserve (CTA-FFR). Twenty-one patients who underwent coronary CTA and invasive FFR were retrospectively identified. Ischemia was defined as invasive FFR ≤0.80. Using a work-in-progress computational fluid dynamics algorithm, CTA-FFR was computed with BP measured before CTA, and simulated BPs of 60/50, 90/60, 110/70, 130/80, 150/90, and 180/100 mmHg respectively. Correlation between CTA-FFR and invasive FFR was assessed using Pearson test. The repeated measuring test was used for multiple comparisons of CTA-FFR values by simulated BP inputs. Twenty-nine vessels (14 with invasive FFR ≤0.80) were assessed. The average CTA-FFR for measured BP (134 ± 20/73 ± 12 mmHg) was 0.77 ± 0.12. Correlation between CTA-FFR by measured BP and invasive FFR was good (r = 0.735, P < 0.001). For simulated BPs of 60/50, 90/60, 110/70, 130/80, 150/90, and 180/100 mmHg, the CTA-FFR increased: 0.69 ± 0.13, 0.73 ± 0.12, 0.75 ± 0.12, 0.77 ± 0.11, 0.79 ± 0.11, and 0.81 ± 0.10 respectively (P < 0.05). Measurement of the BP just before CTA is preferred for accurate CTA-FFR simulation. BP variations in the common range slightly affect CTA-FFR. However, inaccurate BP assumptions differing from the patient-specific BP could cause misinterpretation of borderline significant lesions. (orig.)

  13. Coronary plaque quantification and fractional flow reserve by coronary computed tomography angiography identify ischaemia-causing lesions

    DEFF Research Database (Denmark)

    Gaur, Sara; Øvrehus, Kristian Altern; Dey, Damini

    2016-01-01

    AIMS: Coronary plaque characteristics are associated with ischaemia. Differences in plaque volumes and composition may explain the discordance between coronary stenosis severity and ischaemia. We evaluated the association between coronary stenosis severity, plaque characteristics, coronary computed...... tomography angiography (CTA)-derived fractional flow reserve (FFRCT), and lesion-specific ischaemia identified by FFR in a substudy of the NXT trial (Analysis of Coronary Blood Flow Using CT Angiography: Next Steps). METHODS AND RESULTS: Coronary CTA stenosis, plaque volumes, FFRCT, and FFR were assessed...

  14. Coronary risk factors and myocardial blood flow in patients evaluated for coronary artery disease: a quantitative [15O]H2O PET/CT study

    International Nuclear Information System (INIS)

    Danad, Ibrahim; Appelman, Yolande E.; Haan, Stefan de; Allaart, Cornelis P.; Rossum, Albert C. van; Knaapen, Paul; Raijmakers, Pieter G.; Harms, Hendrik J.; Hoekstra, Otto S.; Lammertsma, Adriaan A.; Lubberink, Mark; Oever, Mijntje L.P. van den; Kuijk, Cornelis van

    2012-01-01

    There has been increasing interest in quantitative myocardial blood flow (MBF) imaging over the last years and it is expected to become a routinely used technique in clinical practice. Positron emission tomography (PET) using [ 15 O]H 2 O is the established gold standard for quantification of MBF in vivo. A fundamental issue when performing quantitative MBF imaging is to define the limits of MBF in a clinically suitable population. The aims of the present study were to determine the limits of MBF and to determine the relationship among coronary artery disease (CAD) risk factors, gender and MBF in a predominantly symptomatic patient cohort without significant CAD. A total of 128 patients (mean age 54 ± 10 years, 50 men) with a low to intermediate pretest likelihood of CAD were referred for noninvasive evaluation of CAD using a hybrid PET/computed tomography (PET/CT) scanner. MBF was quantified with [ 15 O]H 2 O at rest and during adenosine-induced hyperaemia. Obstructive CAD was excluded in these patients by means of invasive or CT-based coronary angiography. Global average baseline MBF values were 0.91 ± 0.34 and 1.09 ± 0.30 ml.min -1 .g -1 (range 0.54-2.35 and 0.59-2.75 ml.min -1 .g -1 ) in men and women, respectively (p -1 .g -1 in men and women, respectively; p = 0.08). Global average hyperaemic MBF values were 3.44 ± 1.20 ml.min -1 .g -1 in the whole study population, and 2.90 ± 0.85 and 3.78 ± 1.27 ml.min -1 .g -1 (range 1.52-5.22 and 1.72-8.15 ml.min -1 .g -1 ) in men and women, respectively (p < 0.001). Multivariate analysis identified male gender, age and body mass index as having an independently negative impact on hyperaemic MBF. Gender, age and body mass index substantially influence reference values and should be corrected for when interpreting hyperaemic MBF values. (orig.)

  15. Rubidium-82 PET-CT for quantitative assessment of myocardial blood flow: validation in a canine model of coronary artery stenosis

    Energy Technology Data Exchange (ETDEWEB)

    Lautamaeki, Riikka; Higuchi, Takahiro; Merrill, Jennifer; Voicu, Corina; Bengel, Frank M. [Johns Hopkins Medical Institutions, Department of Radiology, Division of Nuclear Medicine, Baltimore, MD (United States); George, Richard T.; Kitagawa, Kakuya; DiPaula, Anthony; Lima, Joao A.C. [Johns Hopkins Medical Institutions, Department of Medicine, Division of Cardiology, Baltimore, MD (United States); Nekolla, Stephan G. [Technischen Universitaet Muenchen, Nuklearmedizinische Klinik und Poliklinik, Klinikum rechts der Isar, Munich (Germany); Lardo, Albert C. [Johns Hopkins Medical Institutions, Department of Medicine, Division of Cardiology, Baltimore, MD (United States); Johns Hopkins Medical Institutions, Department of Biomedical Engineering, Baltimore, MD (United States)

    2009-04-15

    Absolute quantification of myocardial blood flow expands the diagnostic potential of PET for assessment of coronary artery disease. {sup 82}Rb has significantly contributed to increasing utilization of PET; however, clinical studies are still mostly analysed qualitatively. The aim of this study was to reevaluate the feasibility of {sup 82}Rb for flow quantification, using hybrid PET-CT in an animal model of coronary stenosis. Nine dogs were prepared with experimental coronary artery stenosis. Dynamic PET was performed for 8 min after {sup 82}Rb(1480-1850 MBq) injection during adenosine-induced vasodilation. Microspheres were injected simultaneously for reference flow measurements. CT angiography was used to determine the myocardial regions related to the stenotic vessel. Two methods for flow calculation were employed: a two-compartment model including a spill-over term, and a simplified retention index. The two-compartment model data were in good agreement with microsphere flow (y=0.84x+0.20; r=0.92, p<0.0001), although there was variability in the physiological flow range <3 ml/g per minute (y=0.54x+0.53; r=0.53, p=0.042). Results from the retention index also correlated well with microsphere flow (y=0.47x+0.52; r=0.75, p=0.0004). Error increased with higher flow, but the correlation was good in the physiological range (y=0.62x+0.29; r=0.84, p=0.0001). Using current state-of-the-art PET-CT systems, quantification of myocardial blood flow is feasible with {sup 82}Rb. A simplified approach based on tracer retention is practicable in the physiological flow range. These results encourage further testing of the robustness and usefulness in the clinical context of cardiac hybrid imaging. (orig.)

  16. Rubidium-82 PET-CT for quantitative assessment of myocardial blood flow: validation in a canine model of coronary artery stenosis

    International Nuclear Information System (INIS)

    Lautamaeki, Riikka; Higuchi, Takahiro; Merrill, Jennifer; Voicu, Corina; Bengel, Frank M.; George, Richard T.; Kitagawa, Kakuya; DiPaula, Anthony; Lima, Joao A.C.; Nekolla, Stephan G.; Lardo, Albert C.

    2009-01-01

    Absolute quantification of myocardial blood flow expands the diagnostic potential of PET for assessment of coronary artery disease. 82 Rb has significantly contributed to increasing utilization of PET; however, clinical studies are still mostly analysed qualitatively. The aim of this study was to reevaluate the feasibility of 82 Rb for flow quantification, using hybrid PET-CT in an animal model of coronary stenosis. Nine dogs were prepared with experimental coronary artery stenosis. Dynamic PET was performed for 8 min after 82 Rb(1480-1850 MBq) injection during adenosine-induced vasodilation. Microspheres were injected simultaneously for reference flow measurements. CT angiography was used to determine the myocardial regions related to the stenotic vessel. Two methods for flow calculation were employed: a two-compartment model including a spill-over term, and a simplified retention index. The two-compartment model data were in good agreement with microsphere flow (y=0.84x+0.20; r=0.92, p 82 Rb. A simplified approach based on tracer retention is practicable in the physiological flow range. These results encourage further testing of the robustness and usefulness in the clinical context of cardiac hybrid imaging. (orig.)

  17. Quantitation of myocardial blood flow and myocardial flow reserve with {sup 99m}Tc-sestamibi dynamic SPECT/CT to enhance detection of coronary artery disease

    Energy Technology Data Exchange (ETDEWEB)

    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

  18. 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.)

  19. Elevated admission microalbuminuria predicts poor myocardial blood flow and 6-month mortality in ST-segment elevation myocardial infarction patients undergoing primary percutaneous coronary intervention.

    Science.gov (United States)

    Chen, Jia Wei; Wang, Yong Liang; Li, Hong Wei

    2012-04-01

    Microalbuminuria (MA) is considered a major risk factor predisposing to cardiovascular morbidity and mortality. Outcomes after percutaneous coronary intervention (PCI) for patients with acute myocardial infarction (AMI) complicated by MA have been well described. However, data regarding admission MA and coronary and myocardial flow are scant. The aims of this study were to evaluate the effects of admission MA on coronary blood flow and prognosis in ST-segment elevation myocardial infarction (STEMI) patients undergoing primary PCI. Did elevated admission microalbuminuria predict poor myocardial blood flow and 6-month mortality in ST-segment elevation myocardial infarction patients undergoing primary percutaneous coronary intervention? A total of 247 patients undergoing primary PCI for STEMI within 12 hours after symptom onset were studied. Patients were divided into 2 groups according to admission urinary albumin extraction rate (UAER): (1) an MA group (UAER 20-200 µg/min), and (2) a normoalbuminuria (NA) group (UAER < 20 µg/min). Microalbuminuria was observed in 108 patients. Univariate analyses showed statistical differences between the NA and MA groups in serum creatine level, plasma glucose level, and peak creatine kinase level on presentation. Thrombolysis In Myocardial Infarction (TIMI) flow grades (TFGs) 0-2 in the MA group were more frequent (9.4% vs 21.2%, P < 0.05) than in the NA group, and corrected TIMI frame count was higher (23.9 ± 18.5 vs 29.8 ± 23.5, P < 0.05). Admission MA was an independent predictor of poor myocardial perfusion (adjusted relative risk: 3.14, 95% confidence interval: 0.99-6.78) and a higher rate of 6-month mortality in STEMI patients undergoing primary PCI (adjusted relative risk: 1.58, 95% confidence interval: 0.74-3.39). Admission MA levels are associated with impaired myocardial flow and poor prognosis in STEMI patients undergoing primary PCI. © 2012 Wiley Periodicals, Inc.

  20. Effect of loading-dose ticagrelor on coronary blood flow, left ventricular remodeling and myocardial enzyme spectrum in patients with acute myocardial infarction after interventional therapy

    Directory of Open Access Journals (Sweden)

    Xiao-Rui Xie

    2016-12-01

    Full Text Available Objective: To study the effect of loading-dose ticagrelor on coronary blood flow, left ventricular remodeling and myocardial enzyme spectrum in patients with acute myocardial infarction after interventional therapy. Methods: A total of 86 patients with acute myocardial infarction who received emergency PCI in our hospital between May 2013 and May 2016 were selected and randomly divided into two groups, ticagrelor group received perioperative ticagrelor therapy and clopidogrel group received perioperative clopidogrel therapy. After PCI, coronary blood flow reperfusion was evaluated, serum myocardial remodeling indexes and myocardial enzymes were determined, and cardiac color Doppler ultrasonography was conducted to determine the cardiac function indexes. Results: TIMI grading and TMPG grading of ticagrelor group after PCI were significantly higher than those of clopidogrel group; serum MMP9, BNP, CITP, PICP, PIIINP, CK, CK-MB, cTnI and cTnT content of ticagrelor group 24h after operation were significantly lower than those of clopidogrel group; LVEDD, LVSED and LVMI of ticagrelor group 2 weeks after operation were significantly lower than those of clopidogrel group while LVEF was significantly higher than that of clopidogrel group. Conclusion: Peri-PCI loading-dose ticagrelor can improve coronary blood perfusion and reduce ventricular remodeling and myocardial injury in patients with acute myocardial infarction.

  1. Fractional flow reserve versus angiography for guiding percutaneous coronary intervention

    DEFF Research Database (Denmark)

    Tonino, Pim A L; De Bruyne, Bernard; Pijls, Nico H J

    2009-01-01

    of maximal blood flow in a stenotic artery to normal maximal flow), in addition to angiography, improves outcomes. METHODS: In 20 medical centers in the United States and Europe, we randomly assigned 1005 patients with multivessel coronary artery disease to undergo PCI with implantation of drug......BACKGROUND: In patients with multivessel coronary artery disease who are undergoing percutaneous coronary intervention (PCI), coronary angiography is the standard method for guiding the placement of the stent. It is unclear whether routine measurement of fractional flow reserve (FFR; the ratio...

  2. Flow regulation in coronary vascular tree: a model study.

    Directory of Open Access Journals (Sweden)

    Xinzhou Xie

    Full Text Available Coronary blood flow can always be matched to the metabolic demand of the myocardium due to the regulation of vasoactive segments. Myocardial compressive forces play an important role in determining coronary blood flow but its impact on flow regulation is still unknown. The purpose of this study was to develop a coronary specified flow regulation model, which can integrate myocardial compressive forces and other identified regulation factors, to further investigate the coronary blood flow regulation behavior.A theoretical coronary flow regulation model including the myogenic, shear-dependent and metabolic responses was developed. Myocardial compressive forces were included in the modified wall tension model. Shear-dependent response was estimated by using the experimental data from coronary circulation. Capillary density and basal oxygen consumption were specified to corresponding to those in coronary circulation. Zero flow pressure was also modeled by using a simplified capillary model.Pressure-flow relations predicted by the proposed model are consistent with previous experimental data. The predicted diameter changes in small arteries are in good agreement with experiment observations in adenosine infusion and inhibition of NO synthesis conditions. Results demonstrate that the myocardial compressive forces acting on the vessel wall would extend the auto-regulatory range by decreasing the myogenic tone at the given perfusion pressure.Myocardial compressive forces had great impact on coronary auto-regulation effect. The proposed model was proved to be consistent with experiment observations and can be employed to investigate the coronary blood flow regulation effect in physiological and pathophysiological conditions.

  3. Determination of myocardial blood flow by videodensitometry

    International Nuclear Information System (INIS)

    Erikson, U.; Helmius, G.; Hennig, K.; Johansson, L.; Enghoff, E.; Ruhn, G.

    1981-01-01

    Videodensitometry has hitherto been used as a tool for measuring regional blood flow in the kidneys and lungs by means of the well known Stewart Hamilton curve (wash-out) technique. This preliminary report suggests the possibility of using this method to measure coronary blood flow. Thirty-six patients, 29 of whom had angina pectoris, underwent videodensitometry in connection with coronary angiography. (orig.) [de

  4. Digital radiographic assessment of coronary flow reserve

    International Nuclear Information System (INIS)

    Vogel, R.A.

    1985-01-01

    A method for measuring relative changes in regional blood flow using digital radiographic enhancement of selective coronary arteriography. Coronary flow reserve is measured in individual arterial distributions using the washin ratio of contrast appearance time under baseline and hyperemic conditions. Information is quantitatively presented in functional (parametric) image format. These images, termed contrast medium appearance pictures (CMAP), depict the transit of contrast through the arterial, myocardial and early venous stages. This process can be divided into three general phases: data acquisition, CMAP formation and CMAP analysis. The technique has evolved over its development period from a cine film-based technology which required substantial processing time to a real-time digital radiographic technique

  5. Altered coronary endothelial function in young smokers detected by magnetic resonance assessment of myocardial blood flow during the cold pressor test.

    Science.gov (United States)

    Ichikawa, Yasutaka; Kitagawa, Kakuya; Kato, Shingo; Dohi, Kaoru; Hirano, Tadanori; Ito, Masaaki; Sakuma, Hajime

    2014-06-01

    Endothelial dysfunction is a key element in early atherogenesis. The purposes of this study were to evaluate the feasibility of magnetic resonance (MR) assessment of altered myocardial blood flow (MBF) in response to the cold pressor test (CPT) and to determine if coronary endothelial dysfunction in young smokers can be detected with this noninvasive approach. Fourteen healthy non-smokers (31 ± 6 years) and 12 smokers (34 ± 8 years) were studied. Breath-hold phase-contrast cine MR imaging (PC-MRI) of the coronary sinus (CS) were obtained at rest and during the CPT. MBF was measured as CS flow divided by left ventricle mass and the rate pressure product. In non-smokers, MBF was 0.88 ± 0.19 ml/min/g at rest and significantly increased to 1.13 ± 0.26 ml/min/g during the CPT (P = 0.0001). In smokers, MBF was 0.94 ± 0.26 ml/min/g at rest and 0.96 ± 0.30 ml/min/g during the CPT (P = 0.73). ΔMBF (MBF during the CPT-MBF at rest) was significantly reduced in smokers compared with non-smokers (0.02 ± 0.20 vs. 0.26 ± 0.18 ml/min/g, P = 0.005). The intra-class correlation coefficient between measurements by two observers was 0.90 for ΔMBF. A significant reduction in MBF response to CPT was demonstrated in young smokers with PC-MRI at 1.5 T. This noninvasive method has great potential for assessment of coronary endothelial function.

  6. 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)

  7. Fast virtual functional assessment of intermediate coronary lesions using routine angiographic data and blood flow simulation in humans: comparison with pressure wire - fractional flow reserve.

    Science.gov (United States)

    Papafaklis, Michail I; Muramatsu, Takashi; Ishibashi, Yuki; Lakkas, Lampros S; Nakatani, Shimpei; Bourantas, Christos V; Ligthart, Jurgen; Onuma, Yoshinobu; Echavarria-Pinto, Mauro; Tsirka, Georgia; Kotsia, Anna; Nikas, Dimitrios N; Mogabgab, Owen; van Geuns, Robert-Jan; Naka, Katerina K; Fotiadis, Dimitrios I; Brilakis, Emmanouil S; Garcia-Garcia, Héctor M; Escaned, Javier; Zijlstra, Felix; Michalis, Lampros K; Serruys, Patrick W

    2014-09-01

    To develop a simplified approach of virtual functional assessment of coronary stenosis from routine angiographic data and test it against fractional flow reserve using a pressure wire (wire-FFR). Three-dimensional quantitative coronary angiography (3D-QCA) was performed in 139 vessels (120 patients) with intermediate lesions assessed by wire-FFR (reference standard: ≤0.80). The 3D-QCA models were processed with computational fluid dynamics (CFD) to calculate the lesion-specific pressure gradient (ΔP) and construct the ΔP-flow curve, from which the virtual functional assessment index (vFAI) was derived. The discriminatory power of vFAI for ischaemia- producing lesions was high (area under the receiver operator characteristic curve [AUC]: 92% [95% CI: 86-96%]). Diagnostic accuracy, sensitivity and specificity for the optimal vFAI cut-point (≤0.82) were 88%, 90% and 86%, respectively. Virtual-FAI demonstrated superior discrimination against 3D-QCA-derived % area stenosis (AUC: 78% [95% CI: 70- 84%]; p<0.0001 compared to vFAI). There was a close correlation (r=0.78, p<0.0001) and agreement of vFAI compared to wire-FFR (mean difference: -0.0039±0.085, p=0.59). We developed a fast and simple CFD-powered virtual haemodynamic assessment model using only routine angiography and without requiring any invasive physiology measurements/hyperaemia induction. Virtual-FAI showed a high diagnostic performance and incremental value to QCA for predicting wire-FFR; this "less invasive" approach could have important implications for patient management and cost.

  8. Correlation between coronary computed tomographic angiography and fractional flow reserve

    DEFF Research Database (Denmark)

    Kristensen, Thomas Skaarup; Engstrøm, Thomas; Kelbæk, Henning

    2010-01-01

    Coronary CT angiography (CCTA) has become an important modality to evaluate the presence of coronary artery disease. Coronary artery stenosis of intermediate severity remains a therapeutic dilemma. Measurement of fractional flow reserve (FFR) during coronary angiography is the most established...

  9. Role of Coronary Myogenic Response in Pressure-Flow Autoregulation in Swine: A Meta-Analysis With Coronary Flow Modeling

    Science.gov (United States)

    Dick, Gregory M.; Namani, Ravi; Patel, Bhavesh; Kassab, Ghassan S.

    2018-01-01

    Myogenic responses (pressure-dependent contractions) of coronary arterioles play a role in autoregulation (relatively constant flow vs. pressure). Publications on myogenic reactivity in swine coronaries vary in caliber, analysis, and degree of responsiveness. Further, data on myogenic responses and autoregulation in swine have not been completely compiled, compared, and modeled. Thus, it has been difficult to understand these physiological phenomena. Our purpose was to: (a) analyze myogenic data with standard criteria; (b) assign results to diameter categories defined by morphometry; and (c) use our novel multiscale flow model to determine the extent to which ex vivo myogenic reactivity can explain autoregulation in vivo. When myogenic responses from the literature are an input for our model, the predicted coronary autoregulation approaches in vivo observations. More complete and appropriate data are now available to investigate the regulation of coronary blood flow in swine, a highly relevant model for human physiology and disease. PMID:29875686

  10. Role of Coronary Myogenic Response in Pressure-Flow Autoregulation in Swine: A Meta-Analysis With Coronary Flow Modeling

    Directory of Open Access Journals (Sweden)

    Gregory M. Dick

    2018-05-01

    Full Text Available Myogenic responses (pressure-dependent contractions of coronary arterioles play a role in autoregulation (relatively constant flow vs. pressure. Publications on myogenic reactivity in swine coronaries vary in caliber, analysis, and degree of responsiveness. Further, data on myogenic responses and autoregulation in swine have not been completely compiled, compared, and modeled. Thus, it has been difficult to understand these physiological phenomena. Our purpose was to: (a analyze myogenic data with standard criteria; (b assign results to diameter categories defined by morphometry; and (c use our novel multiscale flow model to determine the extent to which ex vivo myogenic reactivity can explain autoregulation in vivo. When myogenic responses from the literature are an input for our model, the predicted coronary autoregulation approaches in vivo observations. More complete and appropriate data are now available to investigate the regulation of coronary blood flow in swine, a highly relevant model for human physiology and disease.

  11. The relationship between fractional flow reserve, platelet reactivity and platelet leukocyte complexes in stable coronary artery disease

    NARCIS (Netherlands)

    Sels, J.W.E.M.; Rutten, B.; Holten, van T.C.; Hillaert, M.A.K.; Waltenberger, J.; Pijls, N.H.J.; Pasterkamp, G.; Groot, de P.G.; Roest, M.

    2013-01-01

    Background: The presence of stenoses that significantly impair blood flow and cause myocardial ischemia negatively affects prognosis of patients with stable coronary artery disease. Altered platelet reactivity has been associated with impaired prognosis of stable coronary artery disease. Platelets

  12. Measurement of aortic blood flow by magnetic resonance below and above the origin of the coronary arteries in postmenopausal hormone replacement therapy

    DEFF Research Database (Denmark)

    Sørensen, Morten Beck; Fritz-Hansen, Thomas; Jensen, Henrik Halvor

    2004-01-01

    PURPOSE: Principal blood flow measures might be assessable by velocity-encoded cine magnetic resonance (VENC MR) of aortic blood flow. The feasibility of using VENC MR for clinical research was tested in a contemporary and controversial human model: the effects of 17beta-estradiol (E) and cyclic...

  13. Microsphere estimates of blood flow: Methodological considerations

    International Nuclear Information System (INIS)

    von Ritter, C.; Hinder, R.A.; Womack, W.; Bauerfeind, P.; Fimmel, C.J.; Kvietys, P.R.; Granger, D.N.; Blum, A.L.

    1988-01-01

    The microsphere technique is a standard method for measuring blood flow in experimental animals. Sporadic reports have appeared outlining the limitations of this method. In this study the authors have systematically assessed the effect of blood withdrawals for reference sampling, microsphere numbers, and anesthesia on blood flow estimates using radioactive microspheres in dogs. Experiments were performed on 18 conscious and 12 anesthetized dogs. Four blood flow estimates were performed over 120 min using 1 x 10 6 microspheres each time. The effects of excessive numbers of microspheres pentobarbital sodium anesthesia, and replacement of volume loss for reference samples with dextran 70 were assessed. In both conscious and anesthetized dogs a progressive decrease in gastric mucosal blood flow and cardiac output was observed over 120 min. This was also observed in the pancreas in conscious dogs. The major factor responsible for these changes was the volume loss due to the reference sample withdrawals. Replacement of the withdrawn blood with dextran 70 led to stable blood flows to all organs. The injection of excessive numbers of microspheres did not modify hemodynamics to a greater extent than did the injection of 4 million microspheres. Anesthesia exerted no influence on blood flow other than raising coronary flow. The authors conclude that although blood flow to the gastric mucosa and the pancreas is sensitive to the minor hemodynamic changes associated with the microsphere technique, replacement of volume loss for reference samples ensures stable blood flow to all organs over a 120-min period

  14. Relationship between elevated serum gamma-glutamyltransferase activity and slow coronary flow

    DEFF Research Database (Denmark)

    Sen, Nihat; Ozlü, Mehmet F; Basar, Nurcan

    2009-01-01

    OBJECTIVES: We evaluated the relationship between coronary blood flow and serum gamma-glutamyltransferase (GGT) activity in patients with slow coronary flow (SCF). STUDY DESIGN: The study included 90 patients (47 men, 43 women; mean age 50.8+/-9.4 years) with SCF and 88 patients (45 men, 43 women...

  15. Coronary Computed Tomography Angiography Derived Fractional Flow Reserve and Plaque Stress

    DEFF Research Database (Denmark)

    Nørgaard, Bjarne Linde; Leipsic, Jonathon; Koo, Bon-Kwon

    2016-01-01

    Fractional flow reserve (FFR) measured during invasive coronary angiography is an independent prognosticator in patients with coronary artery disease and the gold standard for decision making in coronary revascularization. The integration of computational fluid dynamics and quantitative anatomic...... and physiologic modeling now enables simulation of patient-specific hemodynamic parameters including blood velocity, pressure, pressure gradients, and FFR from standard acquired coronary computed tomography (CT) datasets. In this review article, we describe the potential impact on clinical practice...... and the science behind noninvasive coronary computed tomography (CT) angiography derived fractional flow reserve (FFRCT) as well as future applications of this technology in treatment planning and quantifying forces on atherosclerotic plaques....

  16. Role of endothelial function in coronary slow-flow phenomenon with angiographically normal coronaries

    Directory of Open Access Journals (Sweden)

    Srikanth Nathani

    2016-01-01

    Conclusion: Coronary slow flow phenomenon is a marker of atherosclerosis (as documented by carotid intima media thickness and our study has also shown that endothelial function is significantly impaired in patients with coronary slow flow (as documented by impaired endothelial dependent vasodilatation than that of patients with normal epicardial coronaries with normal flow.

  17. Orthogonal Views of Coronary Vessels: A Method for Imaging the Delivery of Blood Cardioplegia Using Transesophageal Echocardiography.

    Science.gov (United States)

    Maracaja Neto, Luiz F; Modak, Raj; Schonberger, Robert B

    2017-04-01

    Coronary blood flow can be disrupted during cardiac interventions such as mitral valve surgeries, left atrial appendage ligation, transcatheter aortic valve implantation, and aortic procedures involving reimplantation of coronary buttons. Although difficult to accomplish, coronary imaging using transesophageal echocardiography can be performed by the use of orthogonal imaging with the ability for real-time tilt for angle adjustment. The technique described herein allows imaging of the right coronary artery, left main coronary artery bifurcation, left anterior descending, and circumflex coronary arteries. The imaging is facilitated by acquisition during the delivery of blood cardioplegia. Coronary sinus and great cardiac vein imaging also can be obtained during the delivery of retrograde cardioplegia. Although further studies are needed, this imaging technique may prove useful in procedures where coronary flow disruption is suspected or as an additional parameter to confirm delivery of cardioplegia.

  18. Effect of couple stresses on hydromagnetic flow of blood through a ...

    African Journals Online (AJOL)

    The function of the coronary network is to supply blood to the heart; however, in cases of Coronary Artery Disease, the geometry has great influence on the nature of the blood flow and the overall performance of the heart. In this paper, the unsteady non-Newtonian flow of blood under couple stresses and a uniform external ...

  19. Evaluation of Blood Hemodynamics in Vascular Grafts after Total Arterial Coronary Revascularization

    Directory of Open Access Journals (Sweden)

    Ahmad Ali Amirghofran

    2016-07-01

    Full Text Available Arterial grafting has increasingly been advocated for the treatment of coronary artery disease in an attempt to improve the long-term results. In the quest to perform routine total arterial revascularization, composite Y graft methods are gaining popularity. The aim of our study was to evaluate whether blood flow in the left internal thoracic artery can provide sufficient perfusion to the entire cardiac muscle per se. Twenty patients with severe coronary artery stenosis who underwent complete arterial coronary revascularization using a composite graft entered our study. Blood flow in thoracic trunk was evaluated in three phases: cross-clamp on, cross-clamp off, and after weaning the patient from cardiopulmonary bypass. Mean arterial blood pressure in the thoracic trunk in these various positions was 62.7±3.7. left internal thora cic artery can provide sufficient blood flow to the cardiac muscles for both rest and exercise conditions.

  20. Relationship between platelet-to-lymphocyte ratio and coronary slow flow.

    Science.gov (United States)

    Oylumlu, Muhammed; Doğan, Adnan; Oylumlu, Mustafa; Yıldız, Abdülkadir; Yüksel, Murat; Kayan, Fethullah; Kilit, Celal; Amasyalı, Basri

    2015-05-01

    The coronary slow flow phenomenon (CSFP), which is characterized by delayed distal vessel opacification in the absence of significant epicardial coronary disease, is an angiographic finding. The aim of this study is to investigate the association between platelet-to-lymphocyte ratio (PLR) and coronary blood flow rate. This is a retrospective observational study. It was based on two medical centers. A total of 197 patients undergoing coronary angiography were included in the study, 95 of whom were patients with coronary slow flow without stenosis in coronary angiography and 102 of whom had normal coronary arteries and normal flow. The PLR was higher in the coronary slow flow group compared with the control groups (p=0.001). In the correlation analysis, PLR showed a significant correlation with left anterior descending (LAD) artery thrombolysis in myocardial infarction (TIMI) frame count. After multiple logistic regression, high levels of PLR were independently associated with coronary slow flow, together with hemoglobin. PLR was higher in patients with CSFP, and we also showed that PLR was significantly and independently associated with CSFP.

  1. Forward coronary flow normally seen in systole is the result of both forward and concealed back flow

    NARCIS (Netherlands)

    Spaan, J. A.; Breuls, N. P.; Laird, J. D.

    1981-01-01

    Normally systolic coronary blood flow is almost entirely forward. As perfusion pressure was lowered through the autoregulatory range in open-chest dogs, net systolic back flow appeared at approximately 70 mm Hg. Imposing a series resistance (Rs), which impedes both forward and back flow, abolished

  2. 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.

  3. Myocardial flow reserve is influenced by both coronary artery stenosis severity and coronary risk factors in patients with suspected coronary artery disease

    International Nuclear Information System (INIS)

    Tsukamoto, Takahiro; Naya, Masanao; Tsutsui, Hiroyuki; Morita, Koichi; Katoh, Chietsugu; Inubushi, Masayuki; Kuge, Yuji; Tamaki, Nagara

    2006-01-01

    Myocardial flow reserve (MFR) measurement has an important role in assessing the functional severity of coronary artery stenosis. However, a discrepancy between the anatomical severity of coronary artery stenosis and MFR is often observed. Such a discrepancy may be explained by coronary risk factors. In this study, we aimed to investigate the influence of coronary artery stenosis severity and risk factors on MFR. Seventy-four patients suspected to have coronary artery disease and seven age-matched healthy volunteers were enrolled. Myocardial blood flow (MBF) and MFR were measured using 15 O-labelled water PET. Regional MFR was calculated in regions with significant coronary artery stenosis (stenotic regions) and in regions without significant stenosis (remote regions). The contributions of coronary artery stenosis severity and coronary risk factors were assessed using univariate and multivariate analyses. In stenotic regions, MFR correlated inversely with coronary artery stenosis severity (r=-0.50, p<0.01). Univariate analysis did not show any significant difference in MFR between the patients with and the patients without each risk factor. In remote regions, however, MFR was significantly decreased in the diabetes and smoking groups (each p<0.05). By multivariate analysis, diabetes and smoking were independent predictors of MFR (each p<0.05). In the group with more than one risk factor, MFR was significantly lower (2.78±0.79) than in the other group (3.40±1.22, p<0.05). MFR is influenced not only by coronary stenosis severity but also by coronary risk factors. In particular, the influence of risk factors should be considered in regions without severe coronary stenosis. (orig.)

  4. Quantitative relationship between coronary calcium content and coronary flow reserve as assessed by integrated PET/CT imaging

    Energy Technology Data Exchange (ETDEWEB)

    Curillova, Zelmira [Brigham and Women' s Hospital, Division of Nuclear Medicine and Molecular Imaging, Department of Radiology, Boston, MA (United States); VA Boston Healthcare System, Division of Cardiology, Department of Medicine, West Roxbury, MA (United States); Yaman, Bettina F.; Sitek, Arkadius; El Fakhri, Georges [Brigham and Women' s Hospital, Division of Nuclear Medicine and Molecular Imaging, Department of Radiology, Boston, MA (United States); Dorbala, Sharmila [Brigham and Women' s Hospital, Division of Nuclear Medicine and Molecular Imaging, Department of Radiology, Boston, MA (United States); Brigham and Women' s Hospital, Noninvasive Cardiovascular Imaging Program, Departments of Medicine (Cardiology) and Radiology, Boston, MA (United States); Kwong, Raymond Y. [Harvard Medical School, Division of Cardiovascular Medicine, Department of Medicine, Brigham and Women' s Hospital, Boston, MA (United States); Brigham and Women' s Hospital, Noninvasive Cardiovascular Imaging Program, Departments of Medicine (Cardiology) and Radiology, Boston, MA (United States); Anagnostopoulos, Constantinos [Brigham and Women' s Hospital, Division of Nuclear Medicine and Molecular Imaging, Department of Radiology, Boston, MA (United States); Royal Brompton Hospital, Department of Nuclear Medicine, London (United Kingdom); Di Carli, Marcelo F. [Brigham and Women' s Hospital, Division of Nuclear Medicine and Molecular Imaging, Department of Radiology, Boston, MA (United States); Harvard Medical School, Division of Cardiovascular Medicine, Department of Medicine, Brigham and Women' s Hospital, Boston, MA (United States); Brigham and Women' s Hospital, Noninvasive Cardiovascular Imaging Program, Departments of Medicine (Cardiology) and Radiology, Boston, MA (United States); Brigham and Women' s Hospital, Division of Nuclear Medicine and Molecular Imaging, Boston, MA (United States)

    2009-10-15

    To evaluate the relationship between coronary artery calcium (CAC) and coronary vasodilator function. We evaluated 136 patients without known coronary artery disease (CAD) undergoing vasodilator stress {sup 82}Rb PET/CT and CAC scoring who showed normal myocardial perfusion. The CAC score, resting and hyperemic myocardial blood flow (MBF), coronary flow reserve (CFR) and coronary vascular resistance were analyzed. Global and regional CAC scores showed significant but weak inverse correlations with hyperemic MBF (r=-0.31 and r=-0.26, p{<=}0.0002 respectively) and CFR (r=-0.28 and r=-0.2, p{<=}0.001 respectively). With increasing CAC score, there was a modest stepwise decline in CFR on a per-patient basis (1.8{+-}0.5 vs 1.7{+-}0.5 vs 1.5{+-}0.4, p=0.048, with total CAC=0, 1-400 and >400, respectively) and on a per-vessel basis. In multivariable modeling only body mass index and CAC score were predictive of CFR. In patients with an intermediate likelihood of, but without overt, CAD, there is a statistically significant but weak inverse correlation between CAC content and coronary vasodilator function. The strength of this association weakens after adjusting CAC scores for age, gender and coronary risk factors. This suggests that CAC and coronary vasodilator function provide biologically different information regarding atherosclerosis. (orig.)

  5. Quantitative relationship between coronary calcium content and coronary flow reserve as assessed by integrated PET/CT imaging

    International Nuclear Information System (INIS)

    Curillova, Zelmira; Yaman, Bettina F.; Sitek, Arkadius; El Fakhri, Georges; Dorbala, Sharmila; Kwong, Raymond Y.; Anagnostopoulos, Constantinos; Di Carli, Marcelo F.

    2009-01-01

    To evaluate the relationship between coronary artery calcium (CAC) and coronary vasodilator function. We evaluated 136 patients without known coronary artery disease (CAD) undergoing vasodilator stress 82 Rb PET/CT and CAC scoring who showed normal myocardial perfusion. The CAC score, resting and hyperemic myocardial blood flow (MBF), coronary flow reserve (CFR) and coronary vascular resistance were analyzed. Global and regional CAC scores showed significant but weak inverse correlations with hyperemic MBF (r=-0.31 and r=-0.26, p≤0.0002 respectively) and CFR (r=-0.28 and r=-0.2, p≤0.001 respectively). With increasing CAC score, there was a modest stepwise decline in CFR on a per-patient basis (1.8±0.5 vs 1.7±0.5 vs 1.5±0.4, p=0.048, with total CAC=0, 1-400 and >400, respectively) and on a per-vessel basis. In multivariable modeling only body mass index and CAC score were predictive of CFR. In patients with an intermediate likelihood of, but without overt, CAD, there is a statistically significant but weak inverse correlation between CAC content and coronary vasodilator function. The strength of this association weakens after adjusting CAC scores for age, gender and coronary risk factors. This suggests that CAC and coronary vasodilator function provide biologically different information regarding atherosclerosis. (orig.)

  6. Coronary CT Angiography Derived Fractional Flow Reserve

    DEFF Research Database (Denmark)

    Nørgaard, Bjarne Linde; Jensen, Jesper Møller; Blanke, Philipp

    2017-01-01

    Purpose of Review: To summarize the scientific basis of CT derived fractional flow reserve (FFRCT) and present an updated review on the evidence from clinical trials and real-world observational data Recent Findings: In prospective multicenter studies of patients with stable coronary artery disea...... of patients with stable CAD. The optimal FFRCT testing interpretation strategy, as well as the relative cost-efficiency of FFRCT against standard noninvasive functional testing, need further investigation....

  7. Evaluating ocular blood flow

    Directory of Open Access Journals (Sweden)

    Jyotsna Maram

    2017-01-01

    Full Text Available Studies have shown that vascular impairment plays an important role in the etiology and pathogenesis of various ocular diseases including glaucoma, age-related macular degeneration, diabetic retinopathy, and retinal venous occlusive disease. Thus, qualitative and quantitative assessment of ocular blood flow (BF is a topic of interest for early disease detection, diagnosis, and management. Owing to the rapid improvement in technology, there are several invasive and noninvasive techniques available for evaluating ocular BF, with each of these techniques having their own limitations and advantages. This article reviews these important techniques, with a particular focus on Doppler Fourier domain optical coherence tomography (OCT and OCT-angiography.

  8. Arterial bending angle and wall morphology correlate with slow coronary flow: Determination with multidetector CT coronary angiography

    International Nuclear Information System (INIS)

    Kantarci, Mecit; Guendogdu, Fuat; Doganay, Selim; Duran, Cihan; Kalkan, M. Emin; Sagsoz, M. Erdem; Kucuk, Osman; Karakaya, Afak; Kucuk, Ahmet; Akguen, Metin

    2011-01-01

    Background and purpose: The purpose of this study was to assess angulations and vessel wall morphology that could lead to bending head loss in the RCA and LMCA arteries of patients with slow coronary flow (SCF) evaluated by MDCT coronary angiography. Methods: The study involved 51 patients (45 males, mean age: 59.6 years) who were diagnosed with SCF by coronary angiography. Diagnosis of SCF was based on thrombolysis in myocardial infarction (TIMI) frame count. Fifty-one patients with absence of slow flow were selected as the control group. The angulations of the main coronary arteries with the aorta were measured from the axial images obtained through MDCT coronary angiography, and the findings were recorded. In addition, the coronary artery walls of these patients were evaluated. For statistical analysis, SPSS for Windows 10.0 (SPSS Inc., Chicago, IL) was used. For comparisons of the angles, either independent samples t test or the Mann-Whitney U test was used where appropriate. Results: The results of the study indicated that 38 patients had SCF in the LAD. Comparisons of patients with SCF with the controls revealed that in the patients with SCF, the mean angle of the LMCA with the aorta (40.9 ± 20.5 o ) was statistically significantly smaller than the mean angle of the LMCA with the aorta in the control cases (71.8 ± 11 o ). In 12 patients, slow flow was detected in the RCA. Those with slow flow in the RCA had significantly smaller angles (mean: 33.2 ± 20.4 o ) than the other cases (mean: 78.9 ± 10.7 o ). Conclusion: A small angle of origin of the main coronary arteries from the aorta, measured on MDCT examinations is correlated with slow blood flow in those vessels, as calculated by the TIMI frame count in catheter coronary angiography.

  9. Arterial bending angle and wall morphology correlate with slow coronary flow: Determination with multidetector CT coronary angiography

    Energy Technology Data Exchange (ETDEWEB)

    Kantarci, Mecit, E-mail: akkanrad@hotmail.com [Department of Radiology, Medical Faculty, Atatuerk University, Erzurum (Turkey); Guendogdu, Fuat [Department of Cardiology, Medical Faculty, Atatuerk University, Erzurum (Turkey); Doganay, Selim [Department of Radiology, Medical Faculty, Erciyes University, Kayseri (Turkey); Duran, Cihan [Department of Radiology, Bilim University, Florence Nightingale Hospital, Istanbul (Turkey); Kalkan, M. Emin [Department of Cardiology, Medical Faculty, Atatuerk University, Erzurum (Turkey); Sagsoz, M. Erdem [Department of Radiology, Medical Faculty, Atatuerk University, Erzurum (Turkey); Kucuk, Osman [Department of Electronic Engineering, Engineering Faculty, Atatuerk University, Erzurum (Turkey); Karakaya, Afak [Department of Radiology, Medical Faculty, Atatuerk University, Erzurum (Turkey); Kucuk, Ahmet [Department of Mathematics, Science Faculty, Atatuerk University, Erzurum (Turkey); Akguen, Metin [Department of Chest, Medical Faculty, Atatuerk University, Erzurum (Turkey)

    2011-01-15

    Background and purpose: The purpose of this study was to assess angulations and vessel wall morphology that could lead to bending head loss in the RCA and LMCA arteries of patients with slow coronary flow (SCF) evaluated by MDCT coronary angiography. Methods: The study involved 51 patients (45 males, mean age: 59.6 years) who were diagnosed with SCF by coronary angiography. Diagnosis of SCF was based on thrombolysis in myocardial infarction (TIMI) frame count. Fifty-one patients with absence of slow flow were selected as the control group. The angulations of the main coronary arteries with the aorta were measured from the axial images obtained through MDCT coronary angiography, and the findings were recorded. In addition, the coronary artery walls of these patients were evaluated. For statistical analysis, SPSS for Windows 10.0 (SPSS Inc., Chicago, IL) was used. For comparisons of the angles, either independent samples t test or the Mann-Whitney U test was used where appropriate. Results: The results of the study indicated that 38 patients had SCF in the LAD. Comparisons of patients with SCF with the controls revealed that in the patients with SCF, the mean angle of the LMCA with the aorta (40.9 {+-} 20.5{sup o}) was statistically significantly smaller than the mean angle of the LMCA with the aorta in the control cases (71.8 {+-} 11{sup o}). In 12 patients, slow flow was detected in the RCA. Those with slow flow in the RCA had significantly smaller angles (mean: 33.2 {+-} 20.4{sup o}) than the other cases (mean: 78.9 {+-} 10.7{sup o}). Conclusion: A small angle of origin of the main coronary arteries from the aorta, measured on MDCT examinations is correlated with slow blood flow in those vessels, as calculated by the TIMI frame count in catheter coronary angiography.

  10. Studies on asymptomatic cerebral ischemia in coronary heart disease with special reference to evaluation of postural changes in cerebral blood flow with {sup 99m}Tc-ECD brain SPECT

    Energy Technology Data Exchange (ETDEWEB)

    Sinozaki, Hideko [Teikyo Univ., Tokyo (Japan). Faculty of Medicine

    2001-03-01

    Postural changes in cerebral blood flow in patients with coronary heart disease (CHD) were evaluated with SPECT to detect asymptomaic cerebral ischemia (ACI). {sup 99m}Tc-ECD was used as a tracer. We developed a new analysis system for the processing of multiple images, making it possible to avoid the spatial shift in ROIs in different positions. The severity of ACI was classified into 3 groups based on SPECT findings in the supine position: group 1 without any abnormalities in cerebral perfusion, group 2 with a single perfusion defect, and group 3 with a number of perfusion defects. No cerebral siteobserved in any group showed a significant difference between the supine and upright positions in cerebral perfusion. Each group in each position, however, revealed a consistent perfusion pattern characterized by a significant decrease in perfusion in the occipital, temporal and frontal lobes. Moreover, the decrease in the latter two sites was significantly greater than in the former site. Concerning clinical profiles, hypertension and the thickness of the intima and media complex (TIMC) of the common carotid artery significantly correlated with the severity of ACI. Furthermore, in multiple regression analysis, only TIMC was identified as a significant determinant of ACI. In conclusion, cerebral blood flow determined with {sup 99m}Tc-ECD SPECT could accurately detect ACI in patients with CHD. (author)

  11. Fractional flow reserve-guided percutaneous coronary intervention: where to after FAME 2?

    Directory of Open Access Journals (Sweden)

    van de Hoef TP

    2015-12-01

    Full Text Available Tim P van de Hoef,1 Martijn Meuwissen,2 Jan J Piek1 1AMC Heartcentre, Academic Medical Center, University of Amsterdam, Amsterdam, 2Amphia Hospital, Breda, the Netherlands Abstract: Fractional flow reserve (FFR is a well-validated clinical coronary physiological parameter derived from the measurement of coronary pressures and has drastically changed revascularization decision-making in clinical practice. Nonetheless, it is important to realize that FFR is a coronary pressure-derived estimate of coronary blood flow impairment. It is thereby not the same as direct measures of coronary flow impairment that determine the occurrence of signs and symptoms of myocardial ischemia. This consideration is important, since the FAME 2 study documented a limited discriminatory power of FFR to identify stenoses that require revascularization to prevent adverse events. The physiological difference between FFR and direct measures of coronary flow impairment may well explain the findings in FAME 2. This review aims to address the physiological background of FFR, its ambiguities, and its consequences for the application of FFR in clinical practice, as well as to reinterpret the diagnostic and prognostic characteristics of FFR in the light of the recent FAME 2 trial outcomes. Keywords: fractional flow reserve, coronary flow, stable ischemic heart disease

  12. 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.

  13. Regional blood flow studies with radioisotopes

    International Nuclear Information System (INIS)

    Holman, B.L.; McNiel, B.J.; Adelstein, S.J.

    1975-01-01

    The methodological approaches to blood flow analysis include (1) diffusible indicator methods, (2) clearance techniques and (3) nondiffusible indicator methods. In each case, accurate measurements of blood flow can be obtained by developing mathematical models which relate the time-dependent observation derived from following the fate of a radiotracer as a function of time to the physiological process itself. Application of these models to biological systems involves constraints and necessitates compromises which may affect the validity of the measurements. Nevertheless, when these techniques are carefully applied and adequately validated, they have provided critical physiological information about such organ systems as the brain and kidney and promise to provide diagnostic information in patients with suspected coronary and peripheral vascular disease

  14. Impaired blood rheology is associated with endothelial dysfunction in patients with coronary risk factors.

    Science.gov (United States)

    Yagi, Hideki; Sumino, Hiroyuki; Aoki, Tomoyuki; Tsunekawa, Katsuhiko; Araki, Osamu; Kimura, Takao; Nara, Makoto; Ogiwara, Takayuki; Murakami, Masami

    2016-01-01

    To investigate the relationship between blood rheology and endothelial function in patients with coronary risk factors, brachial arterial flow-mediated vasodilatation (FMD), an index of endothelial function and blood passage time (BPT), an index of blood rheology, and fasting blood cell count, glucose metabolism, and plasma fibrinogen, lipid, C-reactive protein, and whole blood viscosity levels were measured in 95 patients with coronary risk factors and 37 healthy controls. Brachial arterial FMD after reactive hyperemia was assessed by ultrasonography. BPT was assessed using the microchannel method. In healthy controls, BPT significantly correlated with FMD (r = - 0.325, p index (BMI; r = 0.530, p measurement of blood rheology using the microchannel method may be useful in evaluating brachial arterial endothelial function as a marker of atherosclerosis in these patients.

  15. Prediction of coronary artery bypass graft flow

    International Nuclear Information System (INIS)

    Tamiya, Eiji; Hada, Yoshiyuki; Asano, Ken-ichi; Iio, Masahiro.

    1991-01-01

    To predict the coronary artery bypass graft (CABG) flow based on the time density curve (TDC) obtained from the digital subtraction aortograms (DSA), we developed a pulsatile CABG model (perfusion pressure 60,130 mmHg, pulse rate 53,126/min, cardiac output 3-7 l/min, diameter of the graft 2.1∼6.0 mm). After positioning the regions of interest (ROI), we injected contrast medium(5∼40 ml/sec, 5∼40 ml) into the outlet conduit. Concerning the TDCs, we calculated appearance time (Ta), peak densities (Dp), peak time (Tp), disappearance time (Td), integral of TDC, ΔTp (difference of Tp between two ROI) and ΔTa (difference of Ta between two ROI). Perfusion pressure, graft flow and output curve were similar to those of patients with CABG. Ta, Tp, Td, and ΔTp were affected by both the injection rate and the volume of the contrast medium; while Dp and the TDC integral were only affected by the latter parameter. Under the same conditions of contrast medium injection, the TDC depended strongly on graft flow, diameter of the graft, output and pulse rate. 21.6+0.92π·d 2 /4·Δ1/ΔTp·60 provided the most accurate estimation of CABG flow (r=0.865, p<0.01). We conclude that densitometric analysis of DSA may be useful in the prediction of CABG flow. (author)

  16. CT Determination of Fractional Flow Reserve in Coronary Lesions

    Directory of Open Access Journals (Sweden)

    Mester András

    2016-12-01

    Full Text Available Invasively determined fractional flow reserve (FFR represents the gold-standard method for the functional evaluation of coronary lesions. Coronary computed tomography angiography (CCTA provides characterization of the coronary anatomy, with important morphological information on the atherosclerotic plaques, but does not offer a hemodynamic evaluation of coronary artery lesions. CT evaluation of FFR (FFRCT is a new noninvasive diagnostic method, which provides anatomical and functional assessment of the whole coronary tree, based on computational techniques, with no more radiation or hyperemic agent administration compared with routine CCTA. Recent studies demonstrated the safety and accuracy of FFRCT and its therapeutic use and cost benefits in real-world clinical use.

  17. Biochemical characterization of blood plasma of coronary artery ...

    Indian Academy of Sciences (India)

    This study aimed to investigate the biochemical profile of blood plasma of patients with coronary artery disease (CAD) and angiographically normal subjects (controls) to determine biomarkers for their differentiation. In this double blind study, 5 mL venous blood was drawn before angiography from CAD patients (n=60) and ...

  18. Restoration of myocardial blood flow following percutaneous coronary balloon dilatation and stent implantation: Assessment with qualitative and quantitative contrast-enhanced magnetic resonance imaging

    International Nuclear Information System (INIS)

    Sensky, P.R.; Samani, N.J.; Horsfield, M.A.; Cherryman, G.R.

    2002-01-01

    AIM: To examine the serial use of magnetic resonance imaging (MRI) to evaluate regional myocardial perfusion changes following percutaneous coronary angioplasty and stent implantation (PTCA). MATERIALS AND METHODS: Six patients with single vessel coronary artery disease (CAD) underwent contrast-enhanced first pass MRI immediately prior to (visit A) and within 7 days after (visit B) PTCA. Three sequential short axis slices were obtained after gadodiamide (Gd) bolus (0.025 mmol/kg -1 ) at rest and during adenosine. Each short axis was divided radially into eight regions of interest (ROIs). ROIs were anatomically assigned to a coronary artery territory (CAT). Stress and rest qualitative and quantitative (unidirectional extraction fraction constant (K i ); index of myocardial perfusion reserve (MPRI) = stressK i / restK i ) perfusion parameters were determined for ROI supplied by remote and stenosed/stented vessels for each visit. RESULTS: In stented ROIs the number of ROIs demonstrating normal perfusion, as opposed to reversible perfusion deficits, increased. Qualitative perfusion assessment in remote CATs was unchanged. MPRI in stenotic CATs was lower than in remote CATs at visit A (P < 0.001). Following PTCA, MPRI increased in stented CATs (P < 0.001) but was unchanged in remote CATs. CONCLUSION: Restoration of myocardial perfusion following PTCA can be delineated with qualitative and quantitative perfusion MRI. Although at present the investigation is technically complex and not perfectly sensitive or specific, MRI has the potential to be a valuable tool for patient follow-up and evaluation of revascularization strategy efficacy. Sensky, P.R. et al. (2002)

  19. Myocardial blood flow during induced aortic hypertension in dogs

    International Nuclear Information System (INIS)

    Thai, B.N.; Levesque, M.J.; Nerem, R.M.

    1986-01-01

    Myocardial blood flow was measured in anesthetized dogs during control conditions and under conditions where the aortic pressure was increased due to aortic constriction or during infusion. Blood flow was measured using the radioactive microsphere technique. Radioactive microspheres (15 m Ce-141, Sr-85, and Sc-46) were injected under control, aortic constriction and arterenol infusion in four dogs and under control conditions in two others. All microsphere injections were performed under stabilized conditions. It was found that coronary blood flow rose by 80% during aortic constriction and by 158% during arterenol infusion (P < 0.05). This increase in blood flow was not uniform throughout the heart, and higher increases were observed in the middle and apex regions of the left ventricle. Furthermore, under hypertension the increase in blood flow in LAD (left anterior descending) perfused territories was slightly higher than that in CFX (left circumflex) perfused territories

  20. Distribution of ABO Blood Groups and Coronary Artery Calcium.

    Science.gov (United States)

    Wang, Yao; Zhou, Bing-Yang; Zhu, Cheng-Gang; Guo, Yuan-Lin; Wu, Na-Qiong; Qing, Ping; Gao, Ying; Liu, Geng; Dong, Qian; Li, Jian-Jun

    2017-06-01

    ABO blood groups have been confirmed to be associated with cardiovascular diseases such as coronary artery disease. However, whether ABO blood group is correlated with coronary artery calcium (CAC) is still unknown. 301 patients with coronary artery calcium score (CACS) assessed by computed tomography were consecutively enrolled and divided into two groups: with calcium group (CACS>0, n=104) and without calcium group (CACS=0, n=197). Distribution of ABO blood groups was evaluated between the two groups. The percentage of A blood type was significantly higher (p=0.008) and O blood type was significantly lower (p=0.037) in the calcium group. Univariate regression analysis showed that age, total cholesterol, low density lipoprotein cholesterol, high-sensitivity C-reactive protein, A blood type were positively correlated with CAC, and O blood type was inversely associated with CAC. Multivariate regression analysis showed that A blood type was independently associated with CAC (odds ratio: 2.217, 95% confidence interval: 1.260-3.900, p=0.006) even after further adjustment for variables that were clearly different between the two groups. Our data has suggested for the first time that A blood type was an independent risk marker for CAC. Copyright © 2016 Australian and New Zealand Society of Cardiac and Thoracic Surgeons (ANZSCTS) and the Cardiac Society of Australia and New Zealand (CSANZ). Published by Elsevier B.V. All rights reserved.

  1. Dependence of intramyocardial pressure and coronary flow on ventricular loading and contractility: a model study.

    Science.gov (United States)

    Bovendeerd, Peter H M; Borsje, Petra; Arts, Theo; van De Vosse, Frans N

    2006-12-01

    The phasic coronary arterial inflow during the normal cardiac cycle has been explained with simple (waterfall, intramyocardial pump) models, emphasizing the role of ventricular pressure. To explain changes in isovolumic and low afterload beats, these models were extended with the effect of three-dimensional wall stress, nonlinear characteristics of the coronary bed, and extravascular fluid exchange. With the associated increase in the number of model parameters, a detailed parameter sensitivity analysis has become difficult. Therefore we investigated the primary relations between ventricular pressure and volume, wall stress, intramyocardial pressure and coronary blood flow, with a mathematical model with a limited number of parameters. The model replicates several experimental observations: the phasic character of coronary inflow is virtually independent of maximum ventricular pressure, the amplitude of the coronary flow signal varies about proportionally with cardiac contractility, and intramyocardial pressure in the ventricular wall may exceed ventricular pressure. A parameter sensitivity analysis shows that the normalized amplitude of coronary inflow is mainly determined by contractility, reflected in ventricular pressure and, at low ventricular volumes, radial wall stress. Normalized flow amplitude is less sensitive to myocardial coronary compliance and resistance, and to the relation between active fiber stress, time, and sarcomere shortening velocity.

  2. 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

  3. An angiographic technique for coronary fractional flow reserve measurement: in vivo validation.

    Science.gov (United States)

    Takarada, Shigeho; Zhang, Zhang; Molloi, Sabee

    2013-03-01

    Fractional flow reserve (FFR) is an important prognostic determinant in a clinical setting. However, its measurement currently requires the use of invasive pressure wire, while an angiographic technique based on first-pass distribution analysis and scaling laws can be used to measure FFR using only image data. Eight anesthetized swine were instrumented with flow probe on the proximal segment of the left anterior descending (LAD) coronary arteries. Volumetric blood flow from the flow probe (Qp), coronary pressure (Pa) and right atrium pressure (Pv) were continuously recorded. Flow probe-based FFR (FFRq) was measured from the ratio of flow with and without stenosis. To determine the angiography-based FFR (FFRa), the ratio of blood flow in the presence of a stenosis (QS) to theoretically normal blood flow (QN) was calculated. A region of interest in the LAD arterial bed was drawn to generate time-density curves using angiographic images. QS was measured using a time-density curve and the assumption that blood was momentarily replaced with contrast agent during the injection. QN was estimated from the total coronary arterial volume using scaling laws. Pressure-wire measurements of FFR (FFRp), which was calculated from the ratio of distal coronary pressure (Pd) divided by proximal pressure (Pa), were continuously obtained during the study. A total of 54 measurements of FFRa, FFRp, and FFRq were taken. FFRa showed a good correlation with FFRq (FFRa = 0.97 FFRq +0.06, r(2) = 0.80, p < 0.001), although FFRp overestimated the FFRq (FFRp = 0.657 FFRq + 0.313, r(2) = 0.710, p < 0.0001). Additionally, the Bland-Altman analysis showed a close agreement between FFRa and FFRq. This angiographic technique to measure FFR can potentially be used to evaluate both anatomical and physiological assessments of a coronary stenosis during routine diagnostic cardiac catheterization that requires no pressure wires.

  4. Coronary flow velocity reserve by echocardiography

    DEFF Research Database (Denmark)

    Olsen, Rasmus Huan; Pedersen, Lene Rørholm; Snoer, Martin

    2016-01-01

    BACKGROUND: Coronary flow velocity reserve (CFVR) measured by transthoracic Doppler echocardiography of the LAD is used to assess microvascular function but validation studies in clinical settings are lacking. We aimed to assess feasibility, reproducibility and agreement with myocardial flow...... performed within a week (1-week) and for all scans regardless of time gap (total) and to account for scar tissue for patients with and without previous myocardial infarction (MI). RESULTS: Eighty-six patients with median BMI 30.9 (IQR 29.4-32.9) kg × m(-2) and CFVR 2.29 (1.90-2.63) were included. CFVR...... was feasible in 83 (97 %) using a contrast agent in 14 %. For reproducibility overall (n = 21) limits of agreement (LOA) were (-0.75;0.71), within-subjects coefficient of variation (CV) 11 %, and reliability 0.84. For reproducibility within 1-week (n = 13) LOA were (-0.33;0.25), within-subjects CV 5...

  5. Effect of sildenafil citrate (Viagra) on coronary flow in normal subjects.

    Science.gov (United States)

    Ishikura, Fuminobu; Beppu, Shintaro; Ueda, Hiroaki; Nehra, Ajay; Khandheria, Bijoy K

    2008-01-01

    The purpose of this study was to evaluate the effect of sildenafil citrate (Viagra) on coronary function in normal subjects. The study assessed mean blood pressure, left anterior descending coronary artery (LAD) flow, and echocardiographic variables before and 30 and 60 minutes after taking 50 mg of sildenafil citrate. The mean velocity of LAD flow was assessed with Doppler flow imaging. The study subjects were 6 healthy male volunteers (mean age 37 years). The mean velocity of LAD flow increased 60 minutes after taking sildenafil citrate, but there were no other changes. Two volunteers felt mild flashing and one had mild headache during the study. Sildenafil citrate caused vasodilatation in a normal coronary artery without systemic pressure drops. These results suggest that the agent itself did not have negative effects on the heart in normal subjects.

  6. Fractional flow reserve-guided management in stable coronary disease and acute myocardial infarction: recent developments

    Science.gov (United States)

    Berry, Colin; Corcoran, David; Hennigan, Barry; Watkins, Stuart; Layland, Jamie; Oldroyd, Keith G.

    2015-01-01

    Coronary artery disease (CAD) is a leading global cause of morbidity and mortality, and improvements in the diagnosis and treatment of CAD can reduce the health and economic burden of this condition. Fractional flow reserve (FFR) is an evidence-based diagnostic test of the physiological significance of a coronary artery stenosis. Fractional flow reserve is a pressure-derived index of the maximal achievable myocardial blood flow in the presence of an epicardial coronary stenosis as a ratio to maximum achievable flow if that artery were normal. When compared with standard angiography-guided management, FFR disclosure is impactful on the decision for revascularization and clinical outcomes. In this article, we review recent developments with FFR in patients with stable CAD and recent myocardial infarction. Specifically, we review novel developments in our understanding of CAD pathophysiology, diagnostic applications, prognostic studies, clinical trials, and clinical guidelines. PMID:26038588

  7. Evaluation of Coronary Artery Stenosis by Quantitative Flow Ratio During Invasive Coronary Angiography

    DEFF Research Database (Denmark)

    Westra, Jelmer; Tu, Shengxian; Winther, Simon

    2018-01-01

    BACKGROUND: Quantitative flow ratio (QFR) is a novel diagnostic modality for functional testing of coronary artery stenosis without the use of pressure wires and induction of hyperemia. QFR is based on computation of standard invasive coronary angiographic imaging. The purpose of WIFI II (Wire...... patients with suspected coronary artery disease on coronary computed tomographic angiography for diagnostic invasive coronary angiography. Fractional flow reserve (FFR) was measured in all segments with 30% to 90% diameter stenosis. Blinded observers calculated QFR (Medis Medical Imaging bv......, The Netherlands) for comparison with FFR. FFR was measured in 292 lesions from 191 patients. Ten (5%) and 9 patients (5%) were excluded because of FFR and angiographic core laboratory criteria, respectively. QFR was successfully computed in 240 out of 255 lesions (94%) with a mean diameter stenosis of 50...

  8. Quantification of disturbed coronary flow by disturbed vorticity index and relation with fractional flow reserve

    DEFF Research Database (Denmark)

    Chu, Miao; von Birgelen, Clemens; Li, Yingguang

    2018-01-01

    BACKGROUND AND AIMS: The relation between FFR and local coronary flow patterns is incompletely understood. We aimed at developing a novel hemodynamic index to quantify disturbed coronary flow, and to investigate its relationship with lesion-associated pressure-drop, and fractional flow reserve (F...

  9. New blood flow radiopharmaceutical

    International Nuclear Information System (INIS)

    Sargent, T. III; Shulgin, A.T.; Mathis, C.A.; Budinger, T.F.

    1983-01-01

    Our program for research into the causes of mental disorders such as schizophrenia, manic depressive illness and senile dementia has led us to the development of a new radiopharmaceutical agent, IDNNA (4-iodo-2,5-dimethoxy-N,N-dimethylamphetamine). A series of some 15 different 131 I labeled molecules with various substitutions on the amine were synthesized and tested, and the uptake of the 131 I labeled conpounds in rats was measured. The dimethyl amine (IDNNA) had the best brain uptake and brain/blood ratio. When injected into a dog and scanned with a whole-body scanner, the uptake in the brain could be clearly seen and quantified. Plasma sampling at the same time showed that the maximum brain/blood ratio of 8.7 occurred at 8 min after injection, and the concentration in brain remained high for at least 15 min. Labeling is achieved by reacting 131 ICl and the precursor, 2,5-dimethoxy-N,N-dimethyl amphetamine, in glacial acetic acid; the reaction is complete in less than one minute

  10. Estrogen-induced improvement in coronary flow responses during atrial pacing in relation to endothelin-1 levels in postmenopausal women without coronary disease

    Directory of Open Access Journals (Sweden)

    Ioannis Kallikazaros

    2008-06-01

    Full Text Available Ioannis Kallikazaros, Costas Tsioufis, Panagiotis Zambaras, Ioannis Skiadas, Marina Toutouza, Dimitrios Tousoulis, Christodoulos Stefanadis, Pavlos ToutouzasCardiology Department and University Cardiology Clinic, Hippokration Hospital of Athens, GreeceBackground: The cardioprotective role of hormonal replacement therapy remains in doubt, but interest is increasing in the vascular effects of estrogens especially in coronary circulation.Methods: Coronary blood flow (CBF was measured in 24 postmenopausal women (age 55 ± 3 years, whose coronary arteries appeared angiographically normal, during incremental atrial pacing (AP before and 20 minutes after intracoronary administration of either 75 ng/mL 17-β estradiol (treated group, n = 18 or 0.9% saline (controls, n = 6.Results: Before estrogen, no differences in the coronary vasomotor responses at AP between the two groups (p = NS could be detected. After estrogen, in the treated group, at the peak of the second AP, the coronary artery diameter decreased by 0.17 mm (p < 0.005 while the CBF increased by 61 mL/min (p < 0.05. These changes differed significantly from thoseobserved at the peak of first AP (p < 0.001 for both cases. In contrast, in the control group no such changes were observed. The endothelin-1 (ET-1 levels in the coronary sinus were significantly reduced after estrogen infusion, which was negatively correlated with the degree of coronary artery constriction (r = −0.40, p = 0.03 and positively correlated with the increase in CBF (r = 0.54, p = 0.01.Conclusions: In postmenopausal women without coronary artery disease, the intracoronary estrogen infusion mediates a greater increase in CBF and is positively correlated with the reduction of the coronary sinus ET-1 levels at the peak of AP.Keywords: estrogens, coronary blood flow, endothelin-1, coronary interventions

  11. Evaluation of plasma eosinophil count and mean platelet volume in patients with coronary slow flow

    Directory of Open Access Journals (Sweden)

    Mehmet Demir

    2014-01-01

    Full Text Available OBJECTIVE: The pathophysiology of coronary slow flow has not been clearly defined, although multiple abnormalities including arteritis, endothelial dysfunction, and atherothrombosis, have been reported. It is known that eosinophils play an important role in inflammation, endothelial dysfunction, and thrombosis. We aimed to compare the eosinophil counts of coronary slow flow patients versus healthy controls. METHODS: This study included 50 coronary slow flow patients (19 males, mean age 65.6±13.7 years and 30 healthy controls (10 males, mean age 57.86±11.6 years. These participants were evaluated using concurrent routine biochemical tests as well as neutrophil, lymphocyte, and eosinophil counts and mean platelet volume (MPV, which were obtained from the whole blood count. These parameters were compared between groups. RESULTS: The baseline characteristics of the study groups were comparable. The coronary slow flow patients had a higher mean platelet volume and eosinophil count than the control group (8.38±0.86 vs 6.28±1.6 fL and 0.31±0.42 vs 0.09±0.05; p<0.001 and 0.008, respectively. CONCLUSION: Our study demonstrated a relationship between eosinophil count and MPV in patients with coronary slow flow.

  12. Adenosine-induced coronary flow reserve in Watanabe heritable hyperlipidemic rabbits

    Energy Technology Data Exchange (ETDEWEB)

    Shimada, Kazuhiro; Yoshida, Katsuya [Chiba Univ. (Japan). School of Medicine; Tadokoro, Hiroyuki [and others

    2000-12-01

    The Watanabe heritable hyperlipidemic (WHHL) rabbit develops coronary atherosclerosis and hypercholesterolemia because of a genetic deficiency of low-density lipoprotein receptors and is therefore a good animal model for studying the relationships of coronary atherosclerosis, hypercholesterolemia and coronary flow reserve. The aim of the present study was to assess myocardial perfusion at baseline and during adenosine infusion (0.2 mg{center_dot}kg{sup -1}{center_dot}min{sup -1}) in 8 WHHL rabbits (13.8{+-}0.5 months) with {sup 13}N-ammonia, small-animal positron emission tomography (PET) and colored microspheres. Results were compared with those from 6 age-matched Japanese white rabbits. Plaque distribution was also examined in the extramural coronary arteries. All 8 WHHL rabbits had coronary plaques, with 6 showing multiple plaques. Mean global myocardial blood flow (ml{center_dot}min{sup -1}{center_dot}g{sup -1}) did not differ significantly between control and WHHL groups both at baseline (3.67{+-}0.72 vs 4.26{+-}1.12 ml{center_dot}min{sup -1}{center_dot}g{sup -1}, p=NS) and with adenosine (7.92{+-}2.00 vs 9.27{+-}2.91 ml{center_dot}min{sup -1}{center_dot}g{sup -1}, p=NS), nor did coronary flow reserve (2.16{+-}0.37 vs 2.18{+-}0.41, p=NS). None showed evidence of regional perfusion abnormalities by visual and semiquantitative analyses of PET images. It was concluded that WHHL rabbits preserve adenosine-induced coronary flow reserve despite coronary atherosclerosis and hypercholesterolemia, suggesting that a compensatory mechanism develops in this animal model. (author)

  13. Adenosine-induced coronary flow reserve in Watanabe heritable hyperlipidemic rabbits

    International Nuclear Information System (INIS)

    Shimada, Kazuhiro; Yoshida, Katsuya; Tadokoro, Hiroyuki

    2000-01-01

    The Watanabe heritable hyperlipidemic (WHHL) rabbit develops coronary atherosclerosis and hypercholesterolemia because of a genetic deficiency of low-density lipoprotein receptors and is therefore a good animal model for studying the relationships of coronary atherosclerosis, hypercholesterolemia and coronary flow reserve. The aim of the present study was to assess myocardial perfusion at baseline and during adenosine infusion (0.2 mg·kg -1 ·min -1 ) in 8 WHHL rabbits (13.8±0.5 months) with 13 N-ammonia, small-animal positron emission tomography (PET) and colored microspheres. Results were compared with those from 6 age-matched Japanese white rabbits. Plaque distribution was also examined in the extramural coronary arteries. All 8 WHHL rabbits had coronary plaques, with 6 showing multiple plaques. Mean global myocardial blood flow (ml·min -1 ·g -1 ) did not differ significantly between control and WHHL groups both at baseline (3.67±0.72 vs 4.26±1.12 ml·min -1 ·g -1 , p=NS) and with adenosine (7.92±2.00 vs 9.27±2.91 ml·min -1 ·g -1 , p=NS), nor did coronary flow reserve (2.16±0.37 vs 2.18±0.41, p=NS). None showed evidence of regional perfusion abnormalities by visual and semiquantitative analyses of PET images. It was concluded that WHHL rabbits preserve adenosine-induced coronary flow reserve despite coronary atherosclerosis and hypercholesterolemia, suggesting that a compensatory mechanism develops in this animal model. (author)

  14. Regulation of pulpal blood flow

    International Nuclear Information System (INIS)

    Kim, S.

    1985-01-01

    The regulation of blood flow of the dental pulp was investigated in dogs and rats anesthetized with sodium pentobarbital. Pulpal blood flow was altered by variations of local and systemic hemodynamics. Macrocirculatory blood flow (ml/min/100 g) in the dental pulp was measured with both the 133 Xe washout and the 15-microns radioisotope-labeled microsphere injection methods on the canine teeth of dogs, to provide a comparison of the two methods in the same tooth. Microcirculatory studies were conducted in the rat incisor tooth with microscopic determination of the vascular pattern, RBC velocity, and intravascular volumetric flow distribution. Pulpal resistance vessels have alpha- and beta-adrenergic receptors. Activation of alpha-receptors by intra-arterial injection of norepinephrine (NE) caused both a reduction in macrocirculatory Qp in dogs and decreases in arteriolar and venular diameters and intravascular volumetric flow (Qi) in rats. These responses were blocked by the alpha-antagonist PBZ. Activation of beta-receptors by intra-arterial injection of isoproterenal (ISO) caused a paradoxical reduction of Qp in dogs. In rats, ISO caused a transient increase in arteriolar Qi followed by a flow reduction; arteriolar dilation was accompanied by venular constriction. These macrocirculatory and microcirculatory responses to ISO were blocked by the alpha-antagonist propranolol

  15. The association of ABO blood groups with extent of coronary atherosclerosis in Croatian patients suffering from chronic coronary artery disease.

    Science.gov (United States)

    Karabuva, Svjetlana; Carević, Vedran; Radić, Mislav; Fabijanić, Damir

    2013-01-01

    The aim of study was to: 1) examine the relationship between ABO blood groups and extent of coronary atherosclerosis in patients with chronic coronary artery disease (CAD), 2) compare ABO blood groups distribution in CAD patients and general population, 3) examine possible differences in traditional risk factors frequency in CAD patients with different ABO blood groups. In the 646 chronic CAD patients (72.4% males) coronary angiograms were scored by quantitative assessment using multiple angiographic scoring system, Traditional risk factors were self reported or measured by standard methods. ABO blood distribution of patients was compared with group of 651 healthy blood donors (74.6% males). Among all ABO blood group patients there was no significant difference between the extent of coronary atherosclerosis with regard to all the three scoring systems: number of affected coronary arteries (P = 0.857), Gensini score (P = 0.818), and number of segments narrowed > 50% (P = 0.781). There was no significant difference in ABO blood group distribution between CAD patients and healthy blood donors. Among CAD patients, men with blood group AB were significantly younger than their pairs with non-AB blood groups (P = 0.008). Among CAD patients with AB blood group, males groups (P = 0.003). No association between ABO blood groups and the extent of coronary atherosclerosis in Croatian CAD patients is observed. Observation that AB blood group might possibly identify Croatian males at risk to develop the premature CAD has to be tested in larger cohort of patients.

  16. Functional assessment of sequential coronary artery fistula and coronary artery stenosis with fractional flow reserve and stress adenosine myocardial perfusion imaging

    Directory of Open Access Journals (Sweden)

    Kuan Leong Yew

    2015-10-01

    Full Text Available Coronary artery fistula is an abnormal connection between one coronary artery to another coronary artery or cardiac chambers. The coronary artery fistula may cause significant shunting of blood and cause “pseudo-stenosis” or “steal phenomenon”. This will also accentuate pre-existing mild-moderate de novo coronary lesions with resultant greater pressure gradient difference across the lesions. Thus, fractional flow reserve can be a useful tool to guide intervention decision on the coronary artery fistula. There are very few published reports regarding the use of FFR to assess coronary artery fistula. In fact, there is no outcome data regarding the deferment of coronary artery fistula intervention when the FFR is not physiologically significant. This case highlighted the use of FFR to evaluate the functional significance of coronary fistula in the setting of ischemia evaluation and it was proven to be safe to defer intervention with good 3 year clinical outcome. Stress adenosine myocardial perfusion imaging correlated with the FFR result.

  17. Association of Indicators of Dehydration and Haemoconcentration with the Coronary Slow Flow Phenomenon

    Directory of Open Access Journals (Sweden)

    Suzan Hatipoğlu

    2010-08-01

    Full Text Available Objectives: The coronary slow flow phenomenon (CSFP, characterized by decreased distal progression of dye to coronary arteries, is a distinct angiographic phenomenon and little is known about its pathophysiology. Although several hypotheses have been suggested, the underlying mechanism of CSFP has not been well established yet.The aim of this study was to determine the roles of indicators of dehydration and haemoconcentration in CSFP which have blood flow abnormality effects. Methods: The study consisted of 33 patients with CSFP (group 1, and 31 normal subjects as control group (group 2 detected by coronary angiography. CSFP was diagnosed by the TIMI frame count method. Serum electrolytes, osmolarity and haematological parameters were measured. Results: Compared with control subjects, patient with CSFP had increased levels of calculated osmolarity, tonicity, sodium, glucose and blood urea nitrogen (BUN. Significant differences were also observed in the haematocrit, haemoglobin concentration, and calculated osmolarity but not in total cholesterol and albumin. Conclusions: The results of the present study indicate that the markers of haemoconcentration and dehydration are significantly associated with CSFP. The markers may be important in the coronary blood flow anomaly.

  18. An Outflow Boundary Condition Model for Noninvasive Prediction of Fractional Flow Reserve in Diseased Coronary Arteries.

    Science.gov (United States)

    Fayssal, Iyad A; Moukalled, Fadl; Alam, Samir; Isma'eel, Hussain

    2018-04-01

    This paper reports on a new boundary condition formulation to model the total coronary myocardial flow and resistance characteristics of the myocardial vascular bed for any specific patient when considered for noninvasive diagnosis of ischemia. The developed boundary condition model gives an implicit representation of the downstream truncated coronary bed. Further, it is based on incorporating patient-specific physiological parameters that can be noninvasively extracted to account for blood flow demand to the myocardium at rest and hyperemic conditions. The model is coupled to a steady three-dimensional (3D) collocated pressure-based finite volume flow solver and used to characterize the "functional significance" of a patient diseased coronary artery segment without the need for predicting the hemodynamics of the entire arterial system. Predictions generated with this boundary condition provide a deep understanding of the inherent challenges behind noninvasive image-based diagnostic techniques when applied to human diseased coronary arteries. The overall numerical method and formulated boundary condition model are validated via two computational-based procedures and benchmarked with available measured data. The newly developed boundary condition is used via a designed computational methodology to (a) confirm the need for incorporating patient-specific physiological parameters when modeling the downstream coronary resistance, (b) explain the discrepancies presented in the literature between measured and computed fractional flow reserve (FFRCT), and (c) discuss the current limitations and future challenges in shifting to noninvasive assessment of ischemia.

  19. Diastolic coronary artery pressure-flow velocity relationships in conscious man.

    Science.gov (United States)

    Dole, W P; Richards, K L; Hartley, C J; Alexander, G M; Campbell, A B; Bishop, V S

    1984-09-01

    We characterised the diastolic pressure-flow velocity relationship in the normal left coronary artery of conscious man before and after vasodilatation with angiographic contrast medium. Phasic coronary artery pressure and flow velocity were measured in ten patients during individual diastoles (0.5 to 1.0 s) using a 20 MHz catheter-tipped, pulsed Doppler transducer. All pressure-flow velocity curves were linear over the diastolic pressure range of 110 +/- 15 (SD) mmHg to 71 +/- 7 mmHg (r = 0.97 +/- 0.01). In the basal state, values for slope and extrapolated zero flow pressure intercept averaged 0.35 +/- 0.12 cm X s-1 X mmHg-1 and 51.7 +/- 8.6 mmHg, respectively. Vasodilatation resulted in a 2.5 +/- 0.5 fold increase in mean flow velocity. The diastolic pressure-flow velocity relationship obtained during peak vasodilatation compared to that during basal conditions was characterised by a steeper slope (0.80 +/- 0.48 cm X s-1 X mmHg-1, p less than 0.001) and lower extrapolated zero flow pressure intercept (37.9 +/- 9.8 mmHg, p less than 0.05). Mean right atrial pressure for the group averaged 4.4 +/- 1.7 mmHg, while left ventricular end-diastolic pressure averaged 8.7 +/- 2.8 mmHg. These observations in man are similar to data reported in the canine coronary circulation which are consistent with a vascular waterfall model of diastolic flow regulation. In this model, coronary blood flow may be regulated by changes in diastolic zero flow pressure as well as in coronary resistance.

  20. Pseudonormalization of transmitral flow pattern during exercise thallium-201 imaging in patients with coronary artery disease

    International Nuclear Information System (INIS)

    Shiota, Takahiro; Sakamoto, Tsuguya; Takenaka, Katsu; Amano, Keiko; Amano, Wataru; Igarashi, Tsutomu; Otake, Takeshi; Sugimoto, Tsuneaki

    1993-01-01

    This study was undertaken to assess the usefulness of Doppler parameters and transmitral blood velocity for detecting abnormalities of left ventricular diastolic function during low-level exercise thallium-201 imaging. The study population consisted of 16 thallium perfusion defect patients with coronary artery disease (mean 61±8 years) and 21 age-matched control subjects (mean 55±5 years) without any thallium perfusion defect. Of the 16 thallium perfusion defect patients, 12 were examined by coronary arteriography, of whom single vessel coronary artery disease was seen in 2 and multivessel coronary artery disease in 10. Patients with mitral regurgitant murmurs were excluded from the study. Peak mitral blood flow velocity was measured in early diastole (E) and during atrial systole (A) and the A/E ratio was calculated. The changes in blood pressure and heart rate after low-level exercise were not significantly different between control and thallium perfusion defect groups. The A/E ratio increased slightly in control subjects from 93±14% at baseline to 100±15% during low-level exercise (p<0.05), whereas in patients with thallium perfusion defect, it decreased significantly from 119±33% at baseline to 92±23% during low-level exercise (p<0.01). Thus pseudonormalization of the A/E ratio during low-level exercise may be valuable in the evaluation of patients with severe or multivessel coronary artery disease. (author)

  1. Role of Coronary Myogenic Response in Pressure-Flow Autoregulation in Swine: A Meta-Analysis With Coronary Flow Modeling

    OpenAIRE

    Gregory M. Dick; Ravi Namani; Bhavesh Patel; Ghassan S. Kassab

    2018-01-01

    Myogenic responses (pressure-dependent contractions) of coronary arterioles play a role in autoregulation (relatively constant flow vs. pressure). Publications on myogenic reactivity in swine coronaries vary in caliber, analysis, and degree of responsiveness. Further, data on myogenic responses and autoregulation in swine have not been completely compiled, compared, and modeled. Thus, it has been difficult to understand these physiological phenomena. Our purpose was to: (a) analyze myogenic d...

  2. 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.)

  3. Cerebral blood-flow tomography

    DEFF Research Database (Denmark)

    Lassen, N A; Henriksen, L; Holm, S

    1983-01-01

    . The Xe-133 flow maps are essentially based on the average Xe-133 concentration over the initial 2 min during and after an inhalation of the inert gas lasting 1 min. These maps agreed very well with the early IMP maps obtained over the initial 10 min following an i.v. bolus injection. The subsequent IMP......, and with low radiation exposure to patient and personnel. On the other hand, IMP gives an image of slightly higher resolution. It also introduces a new class of iodinated brain-seeking compounds allowing, perhaps, imaging of other functions more important than mere blood flow....

  4. Fractional flow reserve is not associated with inflammatory markers in patients with stable coronary artery disease.

    Directory of Open Access Journals (Sweden)

    Jan-Willem E M Sels

    Full Text Available BACKGROUND: Atherosclerosis is an inflammatory condition and increased blood levels of inflammatory biomarkers have been observed in acute coronary syndromes. In addition, high expression of inflammatory markers is associated with worse prognosis of coronary artery disease. The presence and extent of inducible ischemia in patients with stable angina has previously been shown to have strong prognostic value. We hypothesized that evidence of inducible myocardial ischemia by local lesions, as measured by fractional flow reserve (FFR, is associated with increased levels of blood based inflammatory biomarkers. METHODS: Whole blood samples of 89 patients with stable angina pectoris and 16 healthy controls were analyzed. The patients with stable angina pectoris underwent coronary angiography and FFR of all coronary lesions. We analyzed plasma levels of cytokines IL-6, IL-8 and TNF-α and membrane expression of Toll-like receptor 2 and 4, CD11b, CD62L and CD14 on monocytes and granulocytes as markers of inflammation. Furthermore, we quantified the severity of hemodynamically significant coronary artery disease by calculating Functional Syntax Score (FSS, an extension of the Syntax Score. RESULTS: For the majority of biomarkers, we observed lower levels in the healthy control group compared with patients with stable angina who underwent coronary catheterization. We found no difference for any of the selected biomarkers between patients with a positive FFR (≤ 0.75 and negative FFR (>0.80. We observed no relationship between the investigated biomarkers and FSS. CONCLUSION: The presence of local atherosclerotic lesions that result in inducible myocardial ischemia as measured by FFR in patients with stable coronary artery disease is not associated with increased plasma levels of IL-6, IL-8 and TNF-α or increased expression of TLR2 and TLR4, CD11b, CD62L and CD14 on circulating leukocytes.

  5. Dynamic interaction between myocardial contraction and coronary flow.

    Science.gov (United States)

    Beyar, R; Sideman, S

    1997-01-01

    Phasic coronary flow is determined by the dynamic interaction between central hemodynamics and myocardial and ventricular mechanics. Various models, including the waterfall, intramyocardial pump and myocardial structural models, have been proposed for the coronary circulation. Concepts such as intramyocardial pressure, local elastance and others have been proposed to help explain the coronary compression by the myocardium. Yet some questions remain unresolved, and a new model has recently been proposed, linking a muscle collagen fibrous model to a physiologically based coronary model, and accounting for transport of fluids across the capillaries and lymphatic flow between the interstitial space and the venous system. One of the unique features of this model is that the intramyocardial pressure (IMP) in the interstitial space is calculated from the balance of forces and fluid transport in the system, and is therefore dependent on the coronary pressure conditions, the myocardial function and the transport properties of the system. The model predicts a wide range of experimentally observed phenomena associated with coronary compression.

  6. 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.)

  7. Myocardial temperature variation: effect on regional function and coronary flow in dogs

    International Nuclear Information System (INIS)

    D'Ambra, M.N.; Magrassi, P.; Lowenstein, E.; Kyo, S.; Austen, W.G.; Buckley, M.J.; LaRaia, P.J.

    1987-01-01

    Incremental changes in the temperature (28-42.5 0 C) of the anterior left ventricular wall in a canine, working, beating right heart bypass preparation (constant preload, afterload, and heart rate) were produced to measure the effect of regional temperature on myocardial function and blood flow. Circumferential-axis segment lengths were measured with sonomicrometry in both the temperature-varied, left-anterior descending coronary artery (LAD)-supplied myocardium and the normothermic (38 0 C) circumflex-supplied myocardium. Fast thermistors (time constant 0 C), regional systolic shortening decreased 42.2 +/- 10% at 41 0 C and increased 23.3 +/- 6% at 31 0 C. There was no significant change in coronary blood flow or distribution at the three temperatures. Pressure-length areas varied inversely with myocardial temperature. These data demonstrate that there is a reversible inverse relationship between midwall T and ventricular function when heart rate, preload, and afterload are controlled

  8. Testicular blood flow in varicocele

    International Nuclear Information System (INIS)

    Iwamoto, Teruaki; Hirokawa, Makoto.

    1986-01-01

    Radioisotopic scrotal angiography was applied for study of testicular blood flow of patients with varicocele. Following iv. bolus injection of 10 ∼ 20 mCi of Tc human serum albumine, Tc RBC or Tc pertechnetate, time activity curve of radioactivity at corresponding bilateral areas of scrotum was simultaneously generated and compared. Eighty-four patients with overt varicocele (grade 2 and 3) at left side only, were selected for the present study and eight healthy young volunteers were studied as a control group. Three patterns of time activity curves were recognized. They are as follows. Type 1, where radioactivity was accumulated quickly in left side and then decreased gradually. Bilateral time activity curves were asymmetrical. Type 2, where time activity curves rose gradually and to a higher level at the left side than at the right side. Type 3, where bilateral time activity curves increased gradually, and symmetrically. All of the control group showed the same pattern as Type 3. Of the 84 patients examined, 34 patients showed Type 1, including 7 with grade 2 and 27 with grade 3. Twenty-four patients showed Type 2. consisting of 12 with grade 2 and 12 with grade 3. Twenty-six patients showed Type 3, consisting of 14 with grade 2 and 12 with grade 3. We presumed the following about testicular blood flow in varicocele: Type 1 pattern shows retrograde blood flow from the renal vein to the internal spermatic vein, Type 2 pattern shows poor venous return through the internal spermatic vein and Type 3 pattern shows good venous return though the presence of dilatated pampiniform plexus. (author)

  9. Coronary flow reserve in patients with diabetes mellitus and prediabetes.

    Science.gov (United States)

    Atar, Asli I; Altuner, Tugba Kayhan; Bozbas, Huseyin; Korkmaz, Mehmet E

    2012-07-01

    Abnormalities of coronary microcirculation have been reported in patients with diabetes mellitus (DM) even in the presence of normal coronary arteries. It is unknown when the microvascular effects on coronary arteries begin to appear in the DM disease course. Coronary flow reserve (CFR), determined by pharmacological stress transthoracic Doppler echocardiography, is a reliable indicator of coronary microvascular function. We sought to determine the coronary microvascular function of prediabetic patients compared to DM patients and normal population. Seventy-four subjects with normal coronary arteries were enrolled. DM and prediabetes were diagnosed according to American Diabetes Association criteria. All subjects had Doppler recordings of the left anterior descending artery with adenosine infusion at a rate of 0.014 mg/kg per minute. The demographical characteristics and laboratory findings of the three groups were similar (DM group: n = 25, mean age 62 ± 7 years, 19 females; prediabetic group: n = 25, mean age 64 ± 12 years, 21 females; control group: n = 24, mean age 63 ± 7 years, 15 females) except fasting glucose levels. CFR values of the three groups were significantly different (DM group: CFR = 1.75 ± 0.50; prediabetic group: CFR = 2.24 ± 0.43; control group: CFR = 2.38 ± 0.32, P < 0.001). CFR values of DM group were lower than those of prediabetic and control groups (DM vs. prediabetic: P < 0.001, DM vs. control: P < 0.001). However, CFR levels of prediabetic group were not different from those of the control group (P = 0.481). DM was an independent factor predictive of CFR < 2 (OR, 22.69; 95% CI, 6.47-79.51; P < 0.001). Coronary microvascular function seems to be normal in the prediabetic state, but dysfunction appears after DM becomes overt. © 2012, Wiley Periodicals, Inc.

  10. Three-dimensional magnetic resonance coronary angiography using a new blood pool contrast agent : Initial experience

    NARCIS (Netherlands)

    Bedaux, WLF; Hofman, MBM; Wielopolski, PA; de Cock, CC; Hoffmann, [No Value; Oudkerk, M; de Feyter, PJ; van Rossum, AC

    2002-01-01

    Objective: The aim of this feasibility study was to assess the effect of a new blood pool contrast agent on magnetic resonance coronary angiography (MRCA) in patients suspected of having coronary artery disease. Methods: Nine patients referred for diagnostic x-ray coronary, angiography in the

  11. Temperature distribution in atherosclerotic coronary arteries: influence of plaque geometry and flow (a numerical study)

    International Nuclear Information System (INIS)

    Have, A G ten; Gijsen, F J H; Wentzel, J J; Slager, C J; Steen, A F W van der

    2004-01-01

    Intravascular coronary thermography is a method that may detect vulnerable, atherosclerotic plaques and is currently evaluated in a clinical setting. Active macrophages or enzymatic heat releasing processes in vulnerable plaques may act as heat sources. To better understand the parameters of influence on thermographic measurements, numerical simulations have been performed on a model of a coronary artery segment containing a heat source. Heat source parameters and flow were varied to study their influence on temperatures at the lumen wall. Maximal temperature differences at the lumen wall increased when the source volume increased and they differ with the source geometry. The simulations showed that blood flow acts as a coolant to the lumen wall. Blood flow decreased maximal temperatures depending on the source geometry, source volume and the maximal flow velocity. Influence of flow was highest for circumferentially extended sources, up to a factor 3.7, and lowest for longitudinally extended sources, down to a factor 1.9. When cap thickness increased, maximal temperatures decreased and the influence of flow increased. This study shows that correct interpretation of intravascular thermographic measurements requires data on the flow and on the morphologic characteristics of the atherosclerotic plaque

  12. Analysis of digital subtraction coronary angiography for estimation of flow reserve in critical coronary stenosis

    International Nuclear Information System (INIS)

    Kohtoku, Shinya

    1988-01-01

    To examine the accuracy of digital subtraction angiographic assessment of coronary flow reserve in critical coronary stenosis, time-density curve was obtained from digital subtraction coronary angiograms for myocardial region of interest. Time to peak contrast(TPC) and time constant of the washout exponential curve(T) were measured in 14 patients with stable effort angina pectoris and critical one vessel lesion before and after percutaneous transluminal coronary angioplasty(PTCA). All patients had normal left ventricular ejection fraction (59 ± 7 %) and Tl 201 myocardial image at rest. The values of TPC and T were significantly shortened from 5.4 ± 1.3 to 4.5 ± 1.0 sec (p < 0.02) and from 10.9 ± 3.8 to 5.3 ± 1.3 sec(p < 0.001) after PTCA, respectively. However, in 9 of all patients TPC after PTCA showed approximately the same valued as those before PTCA. In 5 experimental dogs with critical circumflex stenosis, coronary flow(CF;Doppler flow meter) and systolic thickning of the posterior wall(by sonomicrometry) at rest were not different from control, however, contrast media-induced reactive hyperemia was markedly attenuated, accompanied with a significant of T (7.7 ± 4.5 vs 15.8 ± 10.9 sec, p < 0.01) and completely unchanged TPC (both 6.8 sec). With simultaneous tracing of CF and time-density curve, TPC and washout phase corresponded with contrast-induced transient CF reduction and hyperemic phase, respectively. We conclude that T might be more sensitive for estimation of CF is maintained almost normal, such as patients with stable effort angina pectoris having normal left ventricular wall motion at rest. (author)

  13. Cutaneous blood flow in psoriasis

    International Nuclear Information System (INIS)

    Klemp, P.; Staberg, B.

    1983-01-01

    The disappearance rate of 133 Xe was studied in 20 patients with psoriasis vulgaris, using an epicutaneous labeling technique in involved skin lesions or normal-appearing skin of the proximal extensor site of the forearm. Control experiments were performed in 10 normal subjects. Calculations of the cutaneous blood flow (CBF) in psoriatic skin lesions were performed using a tissue-to-blood partition coefficient for 133 Xe, lambda c,pso, of 1.2 ml/100 g/min. lambda c,pso was estimated after the relative content of water, lipids, and proteins had been analyzed in psoriatic skin biopsies of 6 patients with untreated psoriasis. The mean relative content of water was markedly reduced to 23.5 +/- 1.5% (SEM), and lipids and proteins were markedly increased to 2.5 +/- 0.7% and 74.0 +/- 2.2, respectively, compared to previously published data for normal skin (water 72.5%, lipids 1%, proteins 26.5%). Mean CBF in untreated psoriatic skin was 63.5 +/- 9.0 ml/100 g/min. This was significantly higher than the mean CBF in 10 normal subjects, 6.3 +/- 0.5 ml/100 g/min (p much less than 0.0001). Mean CBF in normal-appearing skin in patients with psoriasis was 11.0 +/- 1.3 ml/100 g/min. This was significantly higher than CBF in normal subjects (p less than 0.0002)

  14. Estimation of the flow resistances exerted in coronary arteries using a vessel length-based method.

    Science.gov (United States)

    Lee, Kyung Eun; Kwon, Soon-Sung; Ji, Yoon Cheol; Shin, Eun-Seok; Choi, Jin-Ho; Kim, Sung Joon; Shim, Eun Bo

    2016-08-01

    Flow resistances exerted in the coronary arteries are the key parameters for the image-based computer simulation of coronary hemodynamics. The resistances depend on the anatomical characteristics of the coronary system. A simple and reliable estimation of the resistances is a compulsory procedure to compute the fractional flow reserve (FFR) of stenosed coronary arteries, an important clinical index of coronary artery disease. The cardiac muscle volume reconstructed from computed tomography (CT) images has been used to assess the resistance of the feeding coronary artery (muscle volume-based method). In this study, we estimate the flow resistances exerted in coronary arteries by using a novel method. Based on a physiological observation that longer coronary arteries have more daughter branches feeding a larger mass of cardiac muscle, the method measures the vessel lengths from coronary angiogram or CT images (vessel length-based method) and predicts the coronary flow resistances. The underlying equations are derived from the physiological relation among flow rate, resistance, and vessel length. To validate the present estimation method, we calculate the coronary flow division over coronary major arteries for 50 patients using the vessel length-based method as well as the muscle volume-based one. These results are compared with the direct measurements in a clinical study. Further proving the usefulness of the present method, we compute the coronary FFR from the images of optical coherence tomography.

  15. Blood cell interactions and segregation in flow.

    Science.gov (United States)

    Munn, Lance L; Dupin, Michael M

    2008-04-01

    For more than a century, pioneering researchers have been using novel experimental and computational approaches to probe the mysteries of blood flow. Thanks to their efforts, we know that blood cells generally prefer to migrate to the axis of flow, that red and white cells segregate in flow, and that cell deformability and their tendency to reversibly aggregate contribute to the non-Newtonian nature of this unique fluid. All of these properties have beneficial physiological consequences, allowing blood to perform a variety of critical functions. Our current understanding of these unusual flow properties of blood have been made possible by the ingenuity and diligence of a number of researchers, including Harry Goldsmith, who developed novel technologies to visualize and quantify the flow of blood at the level of individual cells. Here we summarize efforts in our lab to continue this tradition and to further our understanding of how blood cells interact with each other and with the blood vessel wall.

  16. Coronary Flow Reserve Predicts Cardiopulmonary Fitness in Patients with Coronary Artery Disease Independently of Systolic and Diastolic Function

    DEFF Research Database (Denmark)

    Snoer, Martin; Olsen, Rasmus Huan; Monk-Hansen, Tea

    2014-01-01

    Aims Despite revascularization and optimal medical treatment, patients with coronary artery disease (CAD) have reduced exercise capacity. In the absence of coronary artery stenosis, coronary flow reserve (CFR) is a measure of coronary microvascular function, and a marker of future poor outcome...... in CAD patients. The aim of this study was to examine the relationship among CFR, systolic and diastolic function, peripheral vascular function, and cardiopulmonary fitness in CAD patients. Methods and Results Forty patients with median left ventricular ejection fraction (LVEF) 49 (interquartile 46....... Conclusions Coronary flow reserve measured noninvasively predicts cardiopulmonary fitness independently of resting systolic and diastolic function in CAD patients, indicating that cardiac output during maximal exercise is dependent on the ability of the coronary circulation to adapt to the higher metabolic...

  17. Blood flow and blood volume in a transplanted rat fibrosarcoma

    International Nuclear Information System (INIS)

    Tozer, G.M.; Morris, C.C.

    1990-01-01

    Blood flow measurements following i.v. infusion of iodi-antipyrine labelled with 14 C ( 14 C-IAP) and blood volume measurements following i.v. injection of 125 I human serum albumin and 51 Cr-labelled red blood cells were made in a transplanted rat fibrosarcoma for comparison with various normal tissues. The tumour-blood partition co-efficient for 14 C-IAP w as found to be 0.79 ± 0.07 which is similar to most of the normal tissues studied. The solubility of 14 C-IAP in plasma was found to be higher than that in whole blood. Blood flow to tumours 3 was found to be 17.9 ± 4.0 ml blood 100 g tissue -1 xmin -1 . These values were considered to be primarily measurements of nutritive flow. Blood in the tumours was found to occupy around 1% of the tissue space which was similar to that found for normal muscle and skin. There was no direct correlation between % blood volume and blood flow for the different tissues studied. Th haematocrit of blood contained in tumour tissue was calculated to be significantly lower than that of blood contained in the normal tissues. It was suspected that permeability of tumour blood vessel walls to 125 I-HSA could have accounted for this difference. (author). 41 refs.; 2 figs.; 3 tabs

  18. Regional cerebral blood flow in schizophrenia

    International Nuclear Information System (INIS)

    Mathew, R.J.; Duncan, G.C.; Weinman, M.L.; Barr, D.L.

    1982-01-01

    Regional cerebral blood flow (rCBF) was measured via xenon133 inhalation technique in 23 patients with schizophrenia and 18 age- and sex-matched controls. The mean blood flow to both hemispheres was found to be lower for the patients. The patients and their controls did not differ on interhemispheric differences in blood flow. There were no differences in rCBF between medicated and unmedicated, subchronic and chronic, and paranoid and nonparanoid patients. Hallucinations were associated with reduced blood flow to several postcentral regions

  19. Regional cerebral blood flow in schizophrenia

    Energy Technology Data Exchange (ETDEWEB)

    Mathew, R.J.; Duncan, G.C.; Weinman, M.L.; Barr, D.L.

    1982-10-01

    Regional cerebral blood flow (rCBF) was measured via xenon133 inhalation technique in 23 patients with schizophrenia and 18 age- and sex-matched controls. The mean blood flow to both hemispheres was found to be lower for the patients. The patients and their controls did not differ on interhemispheric differences in blood flow. There were no differences in rCBF between medicated and unmedicated, subchronic and chronic, and paranoid and nonparanoid patients. Hallucinations were associated with reduced blood flow to several postcentral regions.

  20. Cardiac output and regional blood flow following trauma

    International Nuclear Information System (INIS)

    Malik, A.B.; Loegering, D.J.; Saba, T.M.; Kaplan, J.E.

    1978-01-01

    The changes in cardiac output (2), regional blood blow (2r) and regional vascular resistance, and arterial pressure were studied in rats subjected to moderate (LD0) or severe (LD50) traumatic shock. 2 and 2r were determined using microspheres at 15, 60 and 180 min posttrauma. Arterial pressure decreased in both groups at 15 min and recovered by 3 h after sublethal (LD0) trauma, while arterial pressure did not return to control levels after LD50 trauma. 2 decreased in both groups at 15 min and returned to control only in the LD0 trauma group by 3 h. Cerebral, coronary, and hepatic arterial flows and resistances were maintained in both groups. Renal, intestinal, and splenic flows decreased and resistances were maintained in both groups. Renal, intestinal, and splenic flows decreased and resistances increased in both groups by 15 min and returned to control levels by 3 h only in the LD0 trauma group. Total hepatic and hepatic portal flows decreased at 60 min and returned to control levels at 3 h after LD0 trauma, while there was significant depression in these parameters 3 h after LD50 trauma. Therefore, sublethal and severe trauma resulted in early redistribution of flow favoring the coronary, cerebral, and hepatic arterial beds. However, renal, intestinal, splenic, and portal flows remained depressed only in severely traumatized rats, suggesting that continued hypofusion is a factor in the multiple organ failure and death following severe traumatic injury

  1. 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.)

  2. Three dimensional quantitative coronary angiography can detect reliably ischemic coronary lesions based on fractional flow reserve.

    Science.gov (United States)

    Chung, Woo-Young; Choi, Byoung-Joo; Lim, Seong-Hoon; Matsuo, Yoshiki; Lennon, Ryan J; Gulati, Rajiv; Sandhu, Gurpreet S; Holmes, David R; Rihal, Charanjit S; Lerman, Amir

    2015-06-01

    Conventional coronary angiography (CAG) has limitations in evaluating lesions producing ischemia. Three dimensional quantitative coronary angiography (3D-QCA) shows reconstructed images of CAG using computer based algorithm, the Cardio-op B system (Paieon Medical, Rosh Ha'ayin, Israel). The aim of this study was to evaluate whether 3D-QCA can reliably predict ischemia assessed by myocardial fractional flow reserve (FFR) < 0.80. 3D-QCA images were reconstructed from CAG which also were evaluated with FFR to assess ischemia. Minimal luminal diameter (MLD), percent diameter stenosis (%DS), minimal luminal area (MLA), and percent area stenosis (%AS) were obtained. The results of 3D-QCA and FFR were compared. A total of 266 patients was enrolled for the present study. FFR for all lesions ranged from 0.57 to 1.00 (0.85 ± 0.09). Measurement of MLD, %DS, MLA, and %AS all were significantly correlated with FFR (r = 0.569, 0609, 0.569, 0.670, respectively, all P < 0.001). In lesions with MLA < 4.0 mm(2), %AS of more than 65.5% had a 80% sensitivity and a 83% specificity to predict FFR < 0.80 (area under curve, AUC was 0.878). 3D-QCA can reliably predict coronary lesions producing ischemia and may be used to guide therapeutic approach for coronary artery disease.

  3. Prediction of postpercutaneous coronary intervention myocardial infarction: insights from intravascular imaging, coronary flow, and biomarker evaluation.

    Science.gov (United States)

    Hoole, Stephen P; Hernández-Sánchez, Jules; Brown, Adam J; Giblett, Joel P; Bennett, Martin R; West, Nick E J

    2018-05-01

    Percutaneous coronary intervention-induced myocardial infarction (PMI) has prognostic significance. Identifying patients at high risk for PMI is desirable as it may alter strategy and facilitate early preventative therapy. We therefore sought to establish whether preprocedural demographic, interventional (plaque characteristics and coronary microcirculatory function), and inflammatory, endothelial damage, and platelet-derived biomarker data could predict the risk of PMI. We performed target vessel pressure wire to assess fractional flow reserve, index of microcirculatory resistance (IMR) and coronary flow reserve, plaque characterization by virtual histology intravascular ultrasound, and assayed peripheral biomarkers before uncomplicated PCI in 88 patients. We then analyzed post-PCI cardiac troponin level to adjudicate PMI based on the third universal definition of myocardial infarction. Overall incidence of PMI was 27%. Women [10/15 (66%) vs. 14/73 (19%), PPMI. Preprocedural coronary flow reserve was lower in individuals with a subsequent PMI (1.8±1.2 vs. 2.1±1.3. P=0.03), and patients with higher pre-PCI IMR were more likely to sustain PMI [IMR>22: 10/23 (44%) vs. ≤22: 14/65 (22%), P=0.04], although neither was predictive after multivariate analysis. Plaque characterization by virtual histology intravascular ultrasound did not discriminate those at risk of PMI. However, peripheral venous interleukin (IL)-18 and IL-8 levels were independently negatively and positively associated with PMI, respectively. Women and those with low BMI, particularly when associated with high IL-8 and low IL-18 levels, appear to be at increased risk of PMI.

  4. Dynamics of blood flow: twenty years of achievement

    International Nuclear Information System (INIS)

    Rosendorff, C.

    1988-01-01

    The physiology of blood circulation has evolved from the descriptive phenomenology of William Harvey's time to an interdisciplinary science, involving elements of fluid dynamics, vessel wall mechanics, electrophysiology, cell biology, biochemistry and molecular biology. Most of these new developments have occured during the lifetime of the South African Medical Research Council. Highlights of the research undertaken by the Council regarding circulatory physiology are given. In the 1960s the use of xenon-133 to study the flow of blood to the brain resulted in the first systematic description of cerebral blood flow and its control by sympathetic nerves. During the 1970s this technique was refined and the use of radioactive microspheres for the measurement of tissue blood flow was developed. Research concerning the control of blood vessels in the kidney was also carried out, and this showed that the sympathetic nerves control renal blood flow by releasing a local hormone called renin. The renal release of renin was later recognised as being important in the control of blood pressure. Another development was the discovery that vascular sensitivity to noradrenaline was increased in certain types of liver diseases. An analysis of the blood of patients with obstructive jaundice showed that the substance responsible for this noradrenaline effect was a combination of cholesterol and lipo-protein. This led to the theory that excessive cholesterol in the blood may be dangerous. In the late 1970s a shift in research emphasis to coronary artery physiology occurred and the 1980s saw research move into the area of cell biology

  5. Relationship between coronary flow reserve evaluated by phase-contrast cine cardiovascular magnetic resonance and serum eicosapentaenoic acid

    Science.gov (United States)

    2013-01-01

    Background Long-term intake of long-chain n-3 polyunsaturated fatty acids (n-3 PUFAs), especially eicosapentaenoic acid (EPA) is associated with a low risk for cardiovascular disease. Phase-contrast cine cardiovascular magnetic resonance (PC cine CMR) can assess coronary flow reserve (CFR). The present study investigates the relationship between CFR evaluated by PC cine CMR and the serum EPA. Methods We studied 127 patients (male, 116 (91%); mean age, 72.2 ± 7.4 years) with known or suspected coronary artery disease (CAD). X-ray coronary angiography revealed no significant coronary arterial stenoses (defined as luminal diameter reduction ≥50% on quantitative coronary angiogram (QCA) analysis) in all study participants. Breath-hold PC cine CMR images of the coronary sinus (CS) were acquired to assess blood flow of the CS both at rest and during adenosine triphosphate (ATP) infusion. We calculated CFR as CS blood flow during ATP infusion divided by that at rest. Patients were allocated to groups according to whether they had high (n = 64, EPA ≥ 75.8 μg/mL) or low (n = 63, EPA  2.5, which is the previously reported lower limit of normal flow reserve without obstructive CAD. Multivariate analysis revealed that EPA is an independent predictor of CFR > 2.5 (odds ratio, 1.01; 95% confidence interval, 1.00 – 1.02, p = 0.008). Conclusions The serum EPA is significantly correlated with CFR in CAD patients without significant coronary artery stenosis. PMID:24359564

  6. Vascular structure determines pulmonary blood flow distribution

    Science.gov (United States)

    Hlastala, M. P.; Glenny, R. W.

    1999-01-01

    Scientific knowledge develops through the evolution of new concepts. This process is usually driven by new methodologies that provide observations not previously available. Understanding of pulmonary blood flow determinants advanced significantly in the 1960s and is now changing rapidly again, because of increased spatial resolution of regional pulmonary blood flow measurements.

  7. Regional myocardial blood flow distribution during intracoronary infusion of parathyroid hormone

    International Nuclear Information System (INIS)

    Crass, M.F. III; Lust, R.M.

    1986-01-01

    Although low doses of the biologically-active fragment of parathyroid hormone PTH-(1-34), have been shown to produce potent dilation of the coronary circulation specific regional and transmural (endo/epi) myocardial blood flow (MBF) responses to the hormone have not been described. Anesthetized open-chest mongrel dogs were instrumented to quantitate coronary blood flow and other cardiodynamic parameters. PTH-(1-34) was infused into the left circumflex artery (.008 nmol kg -1 min -1 ). Using the reference withdrawal method, radionuclide-labeled microspheres were injected before (basal flow), during (8 min after new steady-state flow), and after (restoration of basal flow) a 20 min infusion of PTH-(1-34). MFB increased from 76 +- 1.9 to 152 +- 3.5 ml min -1 100 g -1 (P < .001) during PTH-(1-34) infusion. No differences in endo/epi flow ratio or regional coronary blood flow within the left ventricle were detected. Thus, in anesthetized dogs, the increase in MBF observed secondary to the PTH-(1-34)-induced decrease in coronary resistance appeared to be uniform transmurally and regionally, and is probably not the result of a shunting or steal phenomenon

  8. Pressure-flow characteristics and nutritional capacity of coronary veins in dogs

    International Nuclear Information System (INIS)

    Cohen, M.V.; Matsuki, T.; Downey, J.M.

    1988-01-01

    To examine the hemodynamic interdependence of coronary arteries and veins, great cardiac vein (GCV) and left anterior descending (LAD) coronary artery flows of dogs were measured. Although they were not different under base-line conditions, 42.9 +/- 4.1 and 34.9 +/- 5.2 ml/min, respectively, LAD occlusion caused only a 56% decrease in GCV flow, whereas peak GCV flow during reactive hyperemia consistently underestimated peak LAD flow by nearly 40%. The measured hemodynamic data were very closely predicted by a simple model that assumed the presence of a low-resistance venous collateral anastomotic pathway between the GCV and veins outside the LAD territory. The resistance of the venous collaterals averaged 9.9 +/- 3.0% of LAD resistance. Therefore, GCV flow does not solely represent LAD collateral flow when the LAD is occluded, nor is it a reliable indicator of changes in LAD perfusion patterns. Nutritional myocardial perfusion assessed with 133 Xe washout decreased from 0.86 +/- 0.16 to 0.13 +/- 0.02 ml.min-1.g-1 after LAD occlusion, whereas retroperfusion of the GCV with arterial blood enhanced washout by 85% to 0.23 +/- 0.03 ml.min-1.g-1 (P less than 0.005). Retroperfusion was inefficient, however, since only 10% of the isotope injected into the GCV gained access to the myocardium

  9. Bone blood flow and metabolism in humans

    DEFF Research Database (Denmark)

    Heinonen, Ilkka; Kemppainen, Jukka; Kaskinoro, Kimmo

    2012-01-01

    Human bone blood flow and metabolism during physical exercise remains poorly characterised. In the present study we measured femoral bone blood flow and glucose uptake in young healthy subjects by positron emission tomography in three separate protocols. In six women, blood flow was measured...... in femoral bone at rest and during one leg intermittent isometric exercise with increasing exercise intensities. In nine men, blood flow in femur was determined at rest and during dynamic one leg exercise, and two other physiological perturbations: moderate systemic hypoxia (14 O(2) ) at rest and during...... exercise, and during intra-femoral infusion of high-dose adenosine. Bone glucose uptake was measured at rest and during dynamic one leg exercise in five men. The results indicate that isometric exercise increased femoral bone blood flow from rest (1.8 ± 0.6 ml/100g/min) to low intensity exercise (4.1 ± 1...

  10. Subcutaneous blood flow in psoriasis

    International Nuclear Information System (INIS)

    Klemp, P.

    1985-01-01

    The simultaneously recorded disappearance rates of 133 xe from subcutaneous adipose tissue in the crus were studied in 10 patients with psoriasis vulgaris using atraumatic labeling of the tissue in lesional skin (LS) areas and symmetrical, nonlesional skin (NLS) areas. Control experiments were performed bilaterally in 10 younger, healthy subjects. The subcutaneous washout rate constant was significantly higher in LS, 0.79 +/- 0.05 min-1 x 10(2) compared to the washout rate constant of NLS, 0.56 +/- 0.07 min-1. 10(2), or the washout rate constant in the normal subjects, 0.46 +/- 0.17 min-1 x 10(2). The mean washout rate constant in NLS was 25% higher than the mean washout rate constant in the normal subjects. The difference was, however, not statistically significant. Differences in the washout rate constants might be due to abnormal subcutaneous tissue-to-blood partition (lambda) in the LS--and therefore not reflecting the real differences in the subcutaneous blood flow (SBF). The lambda for 133 Xe was therefore measured--using a double isotope washout method ( 133 Xe and [ 131 I]antipyrine)--in symmetrical sites of the lateral crus in LS and NLS of 10 patients with psoriasis vulgaris and in 10 legs of normal subjects. In LS the lambda was 4.52 +/- 1.67 ml/g, which was not statistically different from that of NLS, 5.25 +/- 2.19 ml/g, nor from that of normal subcutaneous tissue, 4.98 +/- 1.04 ml/g. Calculations of the SBF using the obtained lambda values gave a significantly higher SBF in LS, 3.57 +/- 0.23 ml/100 g/min, compared to SBF in the NLS, 2.94 +/- 0.37 ml/100 g/min. There was no statistically significant difference between SBF in NLS and SBF in the normal subjects. The increased SBF in LS of psoriatics might be a secondary phenomenon to an increased heat loss in the lesional skin

  11. Coronary grafts flow and cardiac pacing modalities: how to improve perioperative myocardial perfusion.

    LENUS (Irish Health Repository)

    D'Ancona, Giuseppe

    2012-02-03

    OBJECTIVE: Aim of this study was to investigate modifications of coronary grafts flow during different pacing modalities after CABG. MATERIALS AND METHODS: Two separate prospective studies were conducted in patients undergoing CABG and requiring intraoperative epicardial pacing. In a first study (22 patients) coronary grafts flows were measured during dual chamber pacing (DDD) and during ventricular pacing (VVI). In a second study (10 patients) flows were measured during DDD pacing at different atrio-ventricular (A-V) delay periods. A-V delay was adjusted in 25 ms increments from 25 to 250 ms and flow measurements were performed for each A-V delay increment. A transit time flowmeter was used for the measurements. RESULTS: An average of 3.4 grafts\\/patient were performed. In the first study, average coronary graft flow was 47.4+\\/-20.8 ml\\/min during DDD pacing and 41.8+\\/-18.2 ml\\/min during VVI pacing (P = 0.0004). Furthermore average systolic pressure was 94.3+\\/-10.1 mmHg during DDD pacing and 89.6+\\/-12.2 mmHg during VVV pacing (P = 0.0007). No significant differences in diastolic pressure were recorded during the two different pacing modalities. In the second study, maximal flows were achieved during DDD pacing with an A-V delay of 175 ms (54+\\/-9.6 ml\\/min) and minimal flows were detected at 25 ms A-V delay (38.1+\\/-4.7 ml\\/min) (P=ns). No significant differences in systolic or diastolic blood pressure were noticed during the different A-V delays. CONCLUSION: Grafts flowmetry provides an extra tool to direct supportive measures such as cardiac pacing after CABG. DDD mode with A-V delay around 175 ms. should be preferred to allow for maximal myocardial perfusion via the grafts.

  12. Fractional flow reserve in acute coronary syndromes: A review

    Directory of Open Access Journals (Sweden)

    Nikunj R. Shah

    2014-12-01

    Full Text Available Fractional flow reserve (FFR assessment provides anatomical and physiological information that is often used to tailor treatment strategies in coronary artery disease. Whilst robust data validates FFR use in stable ischaemic heart disease, its use in acute coronary syndromes (ACS is less well investigated. We critically review the current data surrounding FFR use across the spectrum of ACS including culprit and non-culprit artery analysis. With adenosine being conventionally used to induce maximal hyperaemia during FFR assessment, co-existent clinical conditions may preclude its use during acute myocardial infarction. Therefore, we include a current review of instantaneous wave free ratio as a novel vasodilator independent method of assessing lesion severity as an alternative strategy to guide revascularisation in ACS.

  13. Gene expression patterns in peripheral blood correlate with the extent of coronary artery disease.

    Directory of Open Access Journals (Sweden)

    Peter R Sinnaeve

    Full Text Available Systemic and local inflammation plays a prominent role in the pathogenesis of atherosclerotic coronary artery disease, but the relationship of whole blood gene expression changes with coronary disease remains unclear. We have investigated whether gene expression patterns in peripheral blood correlate with the severity of coronary disease and whether these patterns correlate with the extent of atherosclerosis in the vascular wall. Patients were selected according to their coronary artery disease index (CADi, a validated angiographical measure of the extent of coronary atherosclerosis that correlates with outcome. RNA was extracted from blood of 120 patients with at least a stenosis greater than 50% (CADi > or = 23 and from 121 controls without evidence of coronary stenosis (CADi = 0. 160 individual genes were found to correlate with CADi (rho > 0.2, P<0.003. Prominent differential expression was observed especially in genes involved in cell growth, apoptosis and inflammation. Using these 160 genes, a partial least squares multivariate regression model resulted in a highly predictive model (r(2 = 0.776, P<0.0001. The expression pattern of these 160 genes in aortic tissue also predicted the severity of atherosclerosis in human aortas, showing that peripheral blood gene expression associated with coronary atherosclerosis mirrors gene expression changes in atherosclerotic arteries. In conclusion, the simultaneous expression pattern of 160 genes in whole blood correlates with the severity of coronary artery disease and mirrors expression changes in the atherosclerotic vascular wall.

  14. Blood Cell Interactions and Segregation in Flow

    OpenAIRE

    Munn, Lance L.; Dupin, Michael M.

    2008-01-01

    For more than a century, pioneering researchers have been using novel experimental and computational approaches to probe the mysteries of blood flow. Thanks to their efforts, we know that blood cells generally prefer to migrate to the axis of flow, that red and white cells segregate in flow, and that cell deformability and their tendency to reversibly aggregate contribute to the non-Newtonian nature of this unique fluid. All of these properties have beneficial physiological consequences, allo...

  15. Sequential topographical portrayal of myocardial blood flow

    Energy Technology Data Exchange (ETDEWEB)

    Richeson, J.F.; Waag, R.C.; Zwierzynski, D.; Schenk, E.A. (Univ. of Rochester School of Medicine and Dentistry, NY (USA))

    1989-08-01

    Methods to portray myocardial blood flow in a two-dimensional continuum are advantageous in that they allow blood flow history to be overlaid on histological or histochemical descriptions of the consequences of ischemia. We describe here autoradiographic methods that allow such portrayals at three separate times during the evolution of ischemic injury. A computer-based image-analysis system was used to derive such flow maps by taking advantage of the physical characteristics of radioactive isotopes.

  16. Relation of ABO Blood Groups to the Plaque Characteristic of Coronary Atherosclerosis.

    Science.gov (United States)

    Huang, Xingtao; Zou, Yongpeng; Li, Lulu; Chen, Shuyuan; Hou, Jingbo; Yu, Bo

    2017-01-01

    The ABO blood types related to morphological characteristics of atherosclerosis plaque are not clear. We aimed to evaluate the relationship between ABO blood groups and the coronary plaque characteristic. We retrospectively identified the target lesions in 392 acute coronary syndrome patients who underwent optical coherence tomography examination before stenting. Subjects were divided into different groups according to different blood types. The fibrous cap thickness was significantly thicker in O type compared with non-O type (0.075 ± 0.033 mm versus 0.061 ± 0.024, p blood type groups even between O type and non-O type group ( p > 0.05). The plaques of O type blood group were exhibited more stably compared with non-O type blood group. Moreover, the non-O type blood group have more serious coronary artery stenosis than O type blood group.

  17. Radioisotopic flow scanning for portal blood flow and portal hypertension

    International Nuclear Information System (INIS)

    Hesdorffer, C.S.; Bezwoda, W.R.; Danilewitz, M.D.; Esser, J.D.; Tobias, M.

    1987-01-01

    The use of a simple, noninvasive, isotope scanning technique for the determination of relative portal blood flow and detection of portal hypertension is described. Using this technique the presence of portal hypertension was demonstrated in seven of nine patients known to have elevated portal venous pressure. By contrast, esophageal varices were demonstrated in only five of these patients, illustrating the potential value of the method. Furthermore, this technique has been adapted to the study of portal blood flow in patients with myeloproliferative disorders with splenomegaly but without disturbances in hepatic architecture. Results demonstrate that the high relative splenic flow resulting from the presence of splenomegaly may in turn be associated with elevated relative portal blood flow and portal hypertension. The theoretic reasons for the development of flow-related portal hypertension and its relationship to splenic blood flow are discussed

  18. Blood flow autoregulation in pedicled flaps

    DEFF Research Database (Denmark)

    Bonde, Christian T; Holstein-Rathlou, Niels-Henrik; Elberg, Jens J

    2009-01-01

    was to evaluate if, and to what extent, a tissue flap could compensate a reduction in blood flow due to an acute constriction of the feed artery. Further, we wanted to examine the possible role of smooth muscle L-type calcium channels in the autoregulatory mechanism by pharmacological intervention with the L......, the flow in the pedicle was reduced and the flow was recorded. RESULTS: The flaps showed a strong autoregulatory response with complete compensation for flow reductions of up to 70-80%. Infusion of nimodipine caused a 28+/-10% increase in blood flow and removed the autoregulation. Papaverine caused...... a further increase in blood flow by 61+/-19%. The time control experiments proved that the experimental procedure was reproducible and stable over time. CONCLUSIONS: A tissue flap can nearly completely compensate for repeated flow reductions of up to 70-80%. This is due to a decrease in the peripheral...

  19. Quantitative blood flow analysis with digital techniques

    International Nuclear Information System (INIS)

    Forbes, G.

    1984-01-01

    The general principles of digital techniques in quantitating absolute blood flow during arteriography are described. Results are presented for a phantom constructed to correlate digitally calculated absolute flow with direct flow measurements. The clinical use of digital techniques in cerebrovascular angiography is briefly described. (U.K.)

  20. Coronary artery bypass grafting without cardiopulmonary bypass and without interruption of native coronary flow using a novel anastomosis site restraining device ("Octopus").

    Science.gov (United States)

    Borst, C; Jansen, E W; Tulleken, C A; Gründeman, P F; Mansvelt Beck, H J; van Dongen, J W; Hodde, K C; Bredée, J J

    1996-05-01

    This study assessed the feasibility of coronary artery bypass grafting on the beating heart without interruption of native coronary blood flow using a novel anastomosis site restraining device. Recently, an end-to-side bypass technique was described that does not require interruption of flow in the recipient artery. By means of a suction device ("Octopus"), in 31 pigs the epicardium was grasped and immobilized through an arm contraption fixed to the operating table. In the first 15 consecutive pigs (study I), the two-dimensional motion of an epicardial beacon was monitored. In 16 subsequent pigs (study II), an internal mammary artery was grafted under the microscope in two steps to a proximal coronary artery segment, without cardiopulmonary bypass. First, the internal mammary artery was sutured end-to-side to the outside of the coronary artery. Secondly, an orifice was punched in the partitioning coronary wall by an excimer laser catheter introduced through a temporary side-branch of the internal mammary artery. Study II: During 43 suction periods in four anastomosis areas, immobilization was achieved for 15 to 169 min (>30 h in total) in 13 open- and 9 closed-chest procedures without hemodynamic deterioration. The area circumscribed by the edges of the beacon trajectory (area in which the anastomosis is to be tracked) was reduced from 73.0 +/- 43.0 mm(2) (mean +/- SD) to 1.3 +/- 0.5 mm(2) (p<0.001) in the open-chest and to 0.2 +/- 0.2 mm(2) in the closed-chest procedure. At 6 weeks, no myocardial or coronary suction lesions were found. Study II: Nonocclusive anastomosis surgery required 25 +/- 3 min. No leakage, serious arrhythmias, graft closure or hemodynamic deterioration occurred during the procedure or for 2 h after ligating the coronary artery proximally. At 6 weeks, all seven grafts were patent. Coronary bypass on the beating heart without interruption of coronary flow is feasible. In both open- and in closed-chest procedures, the "Octopus" reduced

  1. Postradiation regional cerebral blood flow in primates

    International Nuclear Information System (INIS)

    Cockerham, L.G.; Cerveny, T.J.; Hampton, J.D.

    1986-01-01

    Early transient incapacitation (ETI) is the complete cessation of performance during the first 30 min after radiation exposure and performance decrement (PD) is a reduction in performance at the same time. Supralethal doses of radiation have been shown to produce a marked decrease in regional cerebral blood flow in primates concurrent with hypotension and a dramatic release of mast cell histamine. In an attempt to elucidate mechanisms underlying the radiation-induced ETI/PD phenomenon and the postradiation decrease in cerebral blood flow, primates were exposed to 100 Gy (1 Gy = 100 rads), whole-body, gamma radiation. Pontine and cortical blood flows were measured by hydrogen clearance, before and after radiation exposure. Systemic blood pressures were determined simultaneously. Systemic arterial histamine levels were determined preradiation and postradiation. Data obtained indicated that radiated animals showed a decrease in blood flow of 63% in the motor cortex and 51% in the pons by 10 min postradiation. Regional cerebral blood flow of radiated animals showed a slight recovery 20 min postradiation, followed by a fall to the 10 min nadir by 60 min postradiation. Immediately, postradiation systemic blood pressure fell 67% and remained at that level for the remainder of the experiment. Histamine levels in the radiated animals increased a hundredfold 2 min postradiation. This study indicates that regional cerebral blood flow decreases postradiation with the development of hypotension and may be associated temporally with the postradiation release of histamine

  2. THE ALGORITHM OF DETERMINATION OF EYE FUNDUS VESSELS BLOOD FLOW CHARACTERISTICS ON VIDEOSEQUENCE

    Directory of Open Access Journals (Sweden)

    O. V. Nedzvedz

    2018-01-01

    Full Text Available The method of determination of the dynamic characteristics like the vessel diameter change, the linear and volume blood velocities in the vessels of the eye fundus is considered. Such characteristics allow to determine blood flow changes in the microvasculature affecting the blood flow in the brain, kidneys and coronary vessels. Developed algorithm includes four stages: the video sequence stabilization, the vessels segmentation with the help of a neural network, the determination of the instantaneous velocity in the vessels based on the optical flow and the analysis of the results.

  3. Fractional flow reserve versus angiography for guiding percutaneous coronary intervention in patients with multivessel coronary artery disease: 2-year follow-up of the FAME (Fractional Flow Reserve Versus Angiography for Multivessel Evaluation) study

    DEFF Research Database (Denmark)

    Pijls, Nico H J; Fearon, William F; Tonino, Pim A L

    2010-01-01

    The purpose of this study was to investigate the 2-year outcome of percutaneous coronary intervention (PCI) guided by fractional flow reserve (FFR) in patients with multivessel coronary artery disease (CAD).......The purpose of this study was to investigate the 2-year outcome of percutaneous coronary intervention (PCI) guided by fractional flow reserve (FFR) in patients with multivessel coronary artery disease (CAD)....

  4. Coronary angiographic characteristics that influence fractional flow reserve.

    Science.gov (United States)

    Natsumeda, Makoto; Nakazawa, Gaku; Murakami, Tsutomu; Torii, Sho; Ijichi, Takeshi; Ohno, Yohei; Masuda, Naoki; Shinozaki, Norihiko; Ogata, Nobuhiko; Yoshimachi, Fuminobu; Ikari, Yuji

    2015-01-01

    Percutaneous coronary intervention (PCI) guided with fractional flow reserve (FFR) has been shown to improve clinical outcome. Although coronary angiography is the standard method for PCI guidance, the visual severity of stenosis is not always correlated with functional severity, suggesting that there are additional angiographic factors that affect functional ischemia. To evaluate angiographic predictors of positive FFR in stenotic lesions, angiographic characteristics of 260 consecutive patients (362 lesions) who underwent FFR testing from April 2009 to September 2012 were analyzed. A scoring system (STABLED score) using these predictors was developed and compared with quantitative coronary angiography (QCA). %Diameter stenosis >50% (OR, 8.43; P20 mm (OR, 5.40; P=0.0002), and distance from ostium <20 mm (OR, 1.94; P=0.028) were determined as independent predictors of positive FFR. Area under the ROC curve for probability of positive FFR using the STABLED score (Stenosis 2 points, TAndem lesion 1 point, Bifurcation 1 point, LEsion length 1 point, Distance from ostium 1 point) was 0.85, higher than that for QCA stenosis alone (0.76). STABLED score ≥3 had 72.3% sensitivity and 83.6% specificity for predicting positive FFR, and PPV was 76.7%. Specific angiographic features are applicable for predicting functional ischemia. STABLED score correlates well with FFR.

  5. Blood flow determinations utilizing digital densitometry

    International Nuclear Information System (INIS)

    Lois, F.; Mankovich, N.J.; Gomes, A.S.

    1987-01-01

    A method of obtaining relative and absolute blood flow measurements from digital densitometry was evaluated with a simulated vessel phantom and a hydrodynamic model. A digital vascular imaging system capable of acquisition in 512 2 and 1024 2 mode was used. Relative and absolute blood flow were measured using parameters derived from the densitometric curve. Since application of densitometric data to absolute flow measurements requires the vessel diameter, an algorithm for vessel size determination was created. Gray scale changes were demonstrated to be linearly related to contrast concentration. The variance of vessel size determination was significantly different in all combinations of 1024 2 and 512 2 imaging with 15 cm or 35 cm field size. The error in vessel size determination was significantly less using the larger 1024 2 matrix and the smaller 15 cm image intensifier field size, as shown by the smaller variance. In relative flow determinations, there was good correlation between the flow and four parameters of the densitometric curve with no significant differences between 512 2 and 1024 2 imaging. Absolute flow determinations had slightly lower correlation to actual flow but were not significantly different from relative flow determinations. Relative and absolute blood flow determinations can be performed adequately with either 512 2 or 1024 2 imaging. The increased accuracy in vessel size determination with 1024 2 imaging makes this high resolution system potentially perferable to determine absolute blood flow. (orig.)

  6. Fractional flow reserve derived from coronary CT angiography in stable coronary disease: a new standard in non-invasive testing?

    International Nuclear Information System (INIS)

    Noergaard, B.L.; Jensen, J.M.; Leipsic, J.

    2015-01-01

    Fractional flow reserve (FFR) measured during invasive coronary angiography is the gold standard for lesion-specific decisions on coronary revascularization in patients with stable coronary artery disease (CAD). Current guidelines recommend non-invasive functional or anatomic testing as a gatekeeper to the catheterization laboratory. However, the ''holy grail'' in non-invasive testing of CAD is to establish a single test that quantifies both coronary lesion severity and the associated ischemia. Most evidence to date of such a test is based on the addition of computational analysis of FFR to the anatomic information obtained from standard-acquired coronary CTA data sets at rest (FFR CT ). This review summarizes the clinical evidence for the use of FFR CT in stable CAD in context to the diagnostic performance of other non-invasive testing modalities. (orig.)

  7. Brachial blood flow under relative levels of blood flow restriction is decreased in a nonlinear fashion.

    Science.gov (United States)

    Mouser, J Grant; Ade, Carl J; Black, Christopher D; Bemben, Debra A; Bemben, Michael G

    2018-05-01

    Blood flow restriction (BFR), the application of external pressure to occlude venous return and restrict arterial inflow, has been shown to increase muscular size and strength when combined with low-load resistance exercise. BFR in the research setting uses a wide range of pressures, applying a pressure based upon an individual's systolic pressure or a percentage of occlusion pressure; not a directly determined reduction in blood flow. The relationship between relative pressure and blood flow has not been established. To measure blood flow in the arm under relative levels of BFR. Forty-five people (18-40 years old) participated. Arterial occlusion pressure in the right arm was measured using a 5-cm pneumatic cuff. Blood flow in the brachial artery was measured at rest and at pressures between 10% and 90% of occlusion using ultrasound. Blood flow decreased in a nonlinear, stepped fashion. Blood flow decreased at 10% of occlusion and remained constant until decreasing again at 40%, where it remained until 90% of occlusion. The decrease in brachial blood flow is not proportional to the applied relative pressure. The prescription of blood flow restriction should take into account the stimulus provided at each relative level of blood flow. © 2017 Scandinavian Society of Clinical Physiology and Nuclear Medicine. Published by John Wiley & Sons Ltd.

  8. Frequency encoding in renal blood flow regulation

    DEFF Research Database (Denmark)

    Marsh, D.J.; Sosnovtseva, Olga; Pavlov, A.N.

    2005-01-01

    With a model of renal blood flow regulation, we examined consequences of tubuloglomerular feedback (TGF) coupling to the myogenic mechanism via voltage-gated Ca channels. The model reproduces the characteristic oscillations of the two mechanisms and predicts frequency and amplitude modulation...... of the myogenic oscillation by TGF. Analysis by wavelet transforms of single-nephron blood flow confirms that both amplitude and frequency of the myogenic oscillation are modulated by TGF. We developed a double-wavelet transform technique to estimate modulation frequency. Median value of the ratio of modulation...... TGF cycle to the next. We used a blood pressure signal recorded by telemetry from a conscious rat as the input to the model. Blood pressure fluctuations induced variability in the modulation records similar to those found in the nephron blood flow results. Frequency and amplitude modulation can...

  9. Measurement of bone blood flow in sheep

    International Nuclear Information System (INIS)

    Rosenthal, M.S.; Lehner, C.E.; Pearson, D.W.; Kanikula, T.; Adler, G.; Venci, R.; Lanphier, E.H.; DeLuca, P.M. Jr.

    1984-01-01

    Bone blood flow in sheep tibia has been estimated via the measurement of the perfusion limited clearance of 41 Ar from the bone mineral matrix following fast neutron activation of 44 Ca. Tibia blood flows were estimated for the intact sheep, and after the installation of an intramedullary pressure tap to elevate bone marrow pressure by saline infusion. The results indicate that normal blood flow in the tibia is in the range of 1.1 to 3.7 ml/100ml-min in the intact animal and at normal marrow pressure. With an elevated intramedullary pressure of approximately 100 mmHg, the bone blood flow measured varied around 0.5 to 1.1 ml/100ml-min. 12 refs., 5 figs., 1 tab

  10. Peripheral Endothelial Function and Coronary Flow Velocity Reserve Are Not Associated in Women with Angina and No Obstructive Coronary Artery Disease

    DEFF Research Database (Denmark)

    Flintholm Raft, Kristoffer; Frestad, Daria; Michelsen, Marie Mide

    2017-01-01

    PURPOSE: We investigated whether impaired flow-mediated dilation (FMD) and plasma biomarkers reflecting endothelial dysfunction are associated with coronary microvascular dysfunction (CMD) in women with angina and no obstructive coronary artery disease (CAD). METHODS: Patients (n = 194) were rand...

  11. Analysis of serial coronary artery flow patterns early after primary angioplasty: new insights into the dynamics of the microcirculation.

    Science.gov (United States)

    Sharif, Dawod; Rofe, Guy; Sharif-Rasslan, Amal; Goldhammer, Ehud; Makhoul, Nabeel; Shefer, Arie; Hassan, Amin; Rauchfleisch, Shmuel; Rosenschein, Uri

    2008-06-01

    The temporal behavior of the coronary microcirculation in acute myocardial infarction may affect outcome. Diastolic deceleration time and early systolic flow reversal derived from coronary artery blood flow velocity patterns reflect microcirculatory function. To assess left anterior descending coronary artery flow velocity patterns using Doppler transthoracic echocardiography after primary percutaneous coronary intervention, in patients with anterior AMI. Patterns of flow velocity patterns of the LAD were obtained using transthoracic echocardiography-Doppler in 31 consecutive patients who presented with anterior AMI. Measurements were done at 6 hours, 36-48 hours, and 5 days after successful PPCI. Measurements of DDT and pressure half times (Pt%), as well as observation for ESFR were performed. In the first 2 days following PPCI, the average DDT (600 +/- 340 msec) was shorter than on day 5 (807 +/- 332 msec) (P 600 msec) and vice versa. On day 5 most DDTs became longer. Pt1/2 at 6 hours was not different than at day 2 (174 +/- 96 vs. 193 +/- 99 msec, P = NS) and became longer on day 5 (235 +/- 98 msec, P = 0.012). Bidirectional patterns were also observed in the ESFR in 6 patients (19%) at baseline, in 4 (13%) at 36 hours, and in 2 (6.5%) on day 5 after PPCI. Flow velocity patterns of the LAD after PPCI in AMI are dynamic and reflect unpredictable changes in microcirculation.

  12. Blood flow patterns underlie developmental heart defects.

    Science.gov (United States)

    Midgett, Madeline; Thornburg, Kent; Rugonyi, Sandra

    2017-03-01

    Although cardiac malformations at birth are typically associated with genetic anomalies, blood flow dynamics also play a crucial role in heart formation. However, the relationship between blood flow patterns in the early embryo and later cardiovascular malformation has not been determined. We used the chicken embryo model to quantify the extent to which anomalous blood flow patterns predict cardiac defects that resemble those in humans and found that restricting either the inflow to the heart or the outflow led to reproducible abnormalities with a dose-response type relationship between blood flow stimuli and the expression of cardiac phenotypes. Constricting the outflow tract by 10-35% led predominantly to ventricular septal defects, whereas constricting by 35-60% most often led to double outlet right ventricle. Ligation of the vitelline vein caused mostly pharyngeal arch artery malformations. We show that both cardiac inflow reduction and graded outflow constriction strongly influence the development of specific and persistent abnormal cardiac structure and function. Moreover, the hemodynamic-associated cardiac defects recapitulate those caused by genetic disorders. Thus our data demonstrate the importance of investigating embryonic blood flow conditions to understand the root causes of congenital heart disease as a prerequisite to future prevention and treatment. NEW & NOTEWORTHY Congenital heart defects result from genetic anomalies, teratogen exposure, and altered blood flow during embryonic development. We show here a novel "dose-response" type relationship between the level of blood flow alteration and manifestation of specific cardiac phenotypes. We speculate that abnormal blood flow may frequently underlie congenital heart defects. Copyright © 2017 the American Physiological Society.

  13. 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.

  14. Nutrient and nonnutrient renal blood flow

    International Nuclear Information System (INIS)

    Young, J.S.; Passmore, J.C.; Hartupee, D.A.; Baker, C.H.

    1990-01-01

    The role of prostaglandins in the distribution of total renal blood flow (TRBF) between nutrient and nonnutrient compartments was investigated in anesthetized mongrel dogs. Renal blood flow distribution was assessed by the xenon 133 freeze-dissection technique and by rubidium 86 extraction after ibuprofen treatment. Ibuprofen (13 mg/kg) significantly decreased TRBF by 16.3% +/- 1.2% (mean +/- SEM electromagnetic flow probe; p less than 0.005), but did not alter blood flows to the outer cortex (3.7 vs 4.3 ml/min per gram), the inner cortex (2.6 vs 2.7 ml/min per gram), and the other medulla (1.5 vs 1.5 ml/min per gram), which suggests a decrease in nonnutrient flow. In a separate group of animals the effect of reduced blood flow on the nutrient and nonnutrient components was determined by mechanically reducing renal arterial blood flow by 48%. Unlike the ibuprofen group, nutrient blood flows were proportionally reduced with the mechanical decrease in TRBF in the outer cortex (1.9 ml/min per gram, p less than 0.05), the inner cortex (1.4 ml/min per gram, p less than 0.05), and the outer medulla (0.8 ml/min per gram, p less than 0.01). These results indicate no shift between nutrient and nonnutrient compartments. Nutrient and nonnutrient renal blood flows of the left kidney were also determined by 86Rb extraction. After ibuprofen treatment, nonextracted 86Rb decreased to 12.1% from the control value of 15.6% (p less than 0.05). Mechanical reduction of TRBF did not significantly decrease the proportion of unextracted 86Rb (18.7%)

  15. Continuous infusion thermodilution for assessment of coronary flow: Theoretical background and in vitro validation

    NARCIS (Netherlands)

    Veer, van 't M.; Geven, M.C.F.; Rutten, M.C.M.; Horst, van der A.; Aarnoudse, W.H.; Pijls, N.H.J.; Vosse, van de F.N.

    2009-01-01

    Direct volumetric assessment of coronary flow during cardiac catheterization has not been available so far. In the current study continuous infusion thermodilution, a method based on continuous infusion of saline into a selective coronary artery is evaluated. Theoretically, volumetric flow can be

  16. Impact of top end anastomosis design on patency and flow stability in coronary artery bypass grafting.

    Science.gov (United States)

    Koyama, Sachi; Kitamura, Tadashi; Itatani, Keiichi; Yamamoto, Tadashi; Miyazaki, Shohei; Oka, Norihiko; Nakashima, Kouki; Horai, Tetsuya; Ono, Minoru; Miyaji, Kagami

    2016-05-01

    For coronary artery bypass grafting (CABG), free grafts such as a saphenous vein or radial artery are often used for grafts to the lateral and posterior walls. However, the relationship between top-end anastomosis design and long-term patency remains unknown. Because coronary artery blood flow is dominant during diastole, top-end anastomosis may work better if the graft is directed towards the apex, whereas the shortest graft pathway appears to be most efficient. Using computational fluid dynamic models, we evaluated the hemodynamic variables that were affected by the angle of the top-end anastomosis. We created three-dimensional geometries of the aortic root with coronary arteries that involved 75 % stenosis in the obtuse marginal and postero-lateral branches. Two bypass models under vasodilator administration were created: in a"Model A", the top-end anastomosis is parallel to the long axis of the ascending aorta and the graft passed over the conus directed towards the apex; in a "Model B", the top-end anastomosis is directed toward the shortest pathway, and form near the right angles to the long axis of the ascending aorta. Wall shear stress (WSS) and its fluctuation, an oscillatory shear index (OSI) were evaluated to predict fibrosis progression at the anastomosis site and graft flow. Graft flow was 197.3 ml/min and 207.3 ml/min in the "Model A" and "Model B", respectively. The minimal WSS value inside the graft with the "Model A" and "Model B" was 0.53 Pa and 4.09 Pa, respectively, and the OSI value was 0.46 and 0.04, respectively. The top-end anastomosis of a free graft should be directed vertically towards the aorta to achieve the shortest graft pathway to maintain a high graft flow rate and to avoid the risks of endothelial fibrosis and plaque progression over the long-term after CABG.

  17. Blood Transfusion and the Risk of Acute Kidney Injury Among Patients With Acute Coronary Syndrome Undergoing Percutaneous Coronary Intervention.

    Science.gov (United States)

    Karrowni, Wassef; Vora, Amit Navin; Dai, David; Wojdyla, Daniel; Dakik, Habib; Rao, Sunil V

    2016-09-01

    Acute kidney injury (AKI) complicating percutaneous coronary intervention (PCI) is associated with adverse clinical outcomes. To date, no studies have evaluated the association of blood transfusion with AKI in patients undergoing PCI. We used a retrospective cohort study of all patients with acute coronary syndrome undergoing PCI from CathPCI Registry (n=1 756 864). The primary outcome was AKI defined as the rise in serum creatinine post procedure ≥0.5 mg/dL or ≥25% above baseline values. AKI developed in 9.0% of study sample. Patients with AKI were older, more often women, and had high prevalence of comorbidities, including diabetes mellitus, hypertension, and advanced stages of chronic kidney disease at baseline. Blood transfusion was utilized in 2.2% of patients. In the overall sample, AKI developed in 35.1% of patients who received transfusion versus 8.4% of patients without transfusion (adjusted odds ratio, 4.87 [4.71-5.04]). In the subgroup of patients who sustained bleeding event and received transfusion, the rate of AKI was significantly increased across all preprocedure hemoglobin levels versus no blood transfusion. Similar findings were seen in the subgroup of patients with no bleeding event. Blood transfusion is strongly associated with AKI in patients with acute coronary syndrome undergoing PCI. Further investigation is needed to determine whether a restrictive blood transfusion strategy might improve PCI outcomes by reducing the risk of AKI. © 2016 American Heart Association, Inc.

  18. Continuous Perfusion of Saphenous Vein by Oxygenated Blood during Beating Coronary Surgery

    Directory of Open Access Journals (Sweden)

    Mohammad Hossein Mandegar

    2015-09-01

    Full Text Available Background: The saphenous vein remains the most commonly used conduit for coronary artery bypass surgery (CABG. However, the long-term success of surgical revascularization is largely limited by development of occlusion in vein grafts. Objectives: We sought to reduce graft ischemia by maintaining the blood flow into the harvested vein throughout surgery at lowest costs and without special devices. Patients and Methods: This study was conducted on three hundred patients aged 58.5 ± 8 years undergoing elective first-time off-pump CABG with saphenous veins. Results: In addition to preserving nutritional materials and oxygen, the veins harvested via this novel technique did not go into spasm and were not subjected to high-pressure distension, eventually resulting in minimal damage to the endothelium. Conclusions: This technique confers favorable myocardial function and protection in the presence of left ventricular dysfunction, especially in elderly patients.

  19. Blood pressure reactivity to psychological stress and coronary calcification in the Coronary Artery Risk Development in Young Adults Study.

    Science.gov (United States)

    Matthews, Karen A; Zhu, Sha; Tucker, Diane C; Whooley, Mary A

    2006-03-01

    A longstanding hypothesis is that individuals who exhibit large increases in blood pressure during psychological stress are at risk for atherosclerosis. We tested whether blood pressure changes during psychological stress predict subsequent coronary calcification (CaC) in young healthy adults. We evaluated 2816 healthy black and white women, 20 to 35 years of age, from the Coronary Artery Risk Development in Young Adults Study, who were not using medication for hypertension or diabetes in 1987-1988. Participants completed video game and star tracing tasks while their blood pressure was recorded. Thirteen years later (2000-2001), they completed computed tomography measures of CaC. Overall 9.3% (261 of 2816) had CaC present at follow-up. Each 10 mm Hg change in systolic blood pressure during the video game was associated with a 24% increased odds of having CaC at follow-up (unadjusted odds ratio, 1.24; 95% CI, 1.06 to 1.46; P=0.008). This association persisted after adjustment for age, race, sex, education, smoking, alcohol, family history of myocardial infarction, smoking, daily alcohol consumption, body mass index, and resting or baseline blood pressure (odds ratio, 1.31; 95% CI, 1.08 to 1.58; P=0.006). Blood pressure changes during the star tracing task were not associated with subsequent CaC. Blood pressure changes during a video game predicted the presence of CaC 13 years later. To our knowledge, this is the first study that reports blood pressure reactivity to a stressor being related to calcification in the coronary arteries. Blood pressure reactivity may provide useful prognostic information about future risk beyond standard risk factors.

  20. Insight of Human Stroke from blood flow and blood pressure

    Science.gov (United States)

    Chen, Zhi; Ivanov, Plamen Ch.; Hu, Kun; Stanley, H. Eugene

    2003-03-01

    Stroke is is one of the leading cause of death and disability in the world. It is well believed that stroke is caused by the disturbance of cerebrovascular autoregulation. We investigate the blood flow on the left and right middle cerebral artery and beat-to-beat blood pressure simultaneously measured from the finger, for both subjects with stroke and healthy subjects. Synchronization technique is used to distinguish the difference between these two groups.

  1. Myocardial blood flow assessment with {sup 82}rubidium-PET imaging in patients with left bundle branch block

    Energy Technology Data Exchange (ETDEWEB)

    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

  2. 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

  3. Relation of ABO blood groups to the severity of coronary atherosclerosis: an Gensini score assessment.

    Science.gov (United States)

    Gong, Ping; Luo, Song-Hui; Li, Xiao-Lin; Guo, Yuan-Lin; Zhu, Cheng-Gang; Xu, Rui-Xia; Li, Sha; Dong, Qian; Liu, Geng; Chen, Juan; Zeng, Rui-Xiang; Li, Jian-Jun

    2014-12-01

    Although the study on the relationship between ABO blood groups and coronary atherosclerosis has a long history, few data is available regarding ABO to severity of coronary atherosclerosis in a large cohort study. Therefore, the present study aimed to investigate the relation of the ABO blood groups to the severity of coronary atherosclerosis assessed by Gensini score (GS) in a large Chinese cohort undergoing coronary angiography. A total of 2919 consecutive patients undergoing coronary angiography were enrolled, and their baseline characteristics and ABO blood groups were collected. The GS was calculated as 1st tertile (0-10), 2nd tertile (11-36), 3rd tertile (>36) according to angiographic results. The relation of the ABO blood groups to GS was investigated. The frequency of blood group A was significantly higher in the upper GS tertiles (24.4% vs. 28.2% vs. 29.5%, p = 0.032). Multivariable linear regression analysis revealed that blood group A was independently associated with GS (β = 0.043, p = 0.017). Likewise, multivariable logistic regression analysis showed that group A remained significantly associated with mid-high GS (OR = 1.44, 95% CI 1.16-1.80, p = 0.001), and the group O was showed as a protective factor (OR = 0.77, 95% CI = 0.65-0.92, p = 0.004). In this large Chinese cohort study, the data indicated that there was an association between ABO blood groups and the severity of coronary atherosclerosis. Moreover, the blood group A was an independent risk factor for serious coronary atherosclerosis. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  4. Coronary oscillatory flow amplitude is more affected by perfusion pressure than ventricular pressure.

    Science.gov (United States)

    Krams, R; Sipkema, P; Westerhof, N

    1990-06-01

    In this study on the isolated, maximally vasodilated, blood-perfused cat heart we investigated the relation between left ventricular developed pressure (delta Piv) and coronary oscillatory flow amplitude (diastolic minus systolic flow, delta F) at different levels of constant perfusion pressure (Pp). We hypothesized that the effect of cardiac contraction on the phasic flow results from the changing elastic properties of cardiac muscle. The coronary vessel compartment can, as can the left ventricular lumen compartment, be described by a time-varying elastance. This concept predicts that the effect of left ventricular pressure on delta F is small, whereas the effect of Pp is considerable. Both the waterfall model and the intramyocardial pump model predict the inverse. The relation between delta Piv and delta F at a Pp of 10 kPa is delta F = (4.71 +/- 3.08).delta Piv + 337 +/- 75 (slope in ml.min-1.100 g-1.kPa-1 and intercept in ml.min-1.100 g-1; n = 7); the relation between (constant levels of) Pp and delta F at a constant delta Piv of 10 kPa is delta F = 51.Pp + 211 (slope in ml.min-1.100 g-1.kPa-1 and intercept in ml.min-1.100 g-1; n = 6). The differences in slope are best predicted by the time-varying elastance concept.

  5. Quantification of coronary flow reserve in patients with ischaemic and non-ischaemic cardiomyopathy and its association with clinical outcomes.

    Science.gov (United States)

    Majmudar, Maulik D; Murthy, Venkatesh L; Shah, Ravi V; Kolli, Swathy; Mousavi, Negareh; Foster, Courtney R; Hainer, Jon; Blankstein, Ron; Dorbala, Sharmila; Sitek, Arkadiusz; Stevenson, Lynne W; Mehra, Mandeep R; Di Carli, Marcelo F

    2015-08-01

    Patients with left ventricular systolic dysfunction frequently show abnormal coronary vascular function, even in the absence of overt coronary artery disease. Moreover, the severity of vascular dysfunction might be related to the aetiology of cardiomyopathy.We sought to determine the incremental value of assessing coronary vascular dysfunction among patients with ischaemic (ICM) and non-ischaemic (NICM) cardiomyopathy at risk for adverse cardiovascular outcomes. Coronary flow reserve (CFR, stress/rest myocardial blood flow) was quantified in 510 consecutive patients with rest left ventricular ejection fraction (LVEF) ≤45% referred for rest/stress myocardial perfusion PET imaging. The primary end point was a composite of major adverse cardiovascular events (MACE) including cardiac death, heart failure hospitalization, late revascularization, and aborted sudden cardiac death.Median follow-up was 8.2 months. Cox proportional hazards model was used to adjust for clinical variables. The annualized MACE rate was 26.3%. Patients in the lowest two tertiles of CFR (CFR ≤ 1.65) experienced higher MACE rates than those in the highest tertile (32.6 vs. 15.5% per year, respectively, P = 0.004), irrespective of aetiology of cardiomyopathy. Impaired coronary vascular function, as assessed by reduced CFR by PET imaging, is common in patients with both ischaemic and non-ischaemic cardiomyopathy and is associated with MACE. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2015. For permissions please email: journals.permissions@oup.com.

  6. No benefit of intraoperative whole blood sequestration and autotransfusion during coronary artery bypass grafting : results of a randomized clinical trial

    NARCIS (Netherlands)

    Ramnath, A N; Naber, H R; de Boer, A; Leusink, J A

    OBJECTIVES: In a randomized clinical trial of patients undergoing elective coronary artery bypass grafting, we evaluated the effect of intraoperative whole blood sequestration and autotransfusion on postoperative blood loss and the use of allogeneic blood products. METHODS: Male patients were

  7. Measurement of organ blood flow using tritiated water. II. Uterine blood flow in conscious pregnant ewes

    International Nuclear Information System (INIS)

    Brown, B.W.; Oddy, V.H.; Jones, A.W.

    1982-01-01

    Total uterine blood flow was measured with a tritiated water (TOH) diffusion method and with radioactive microspheres in six, conscious, pregnant ewes. With continuous infusion of TOH, equilibrium between the TOH concentration in utero-ovarian venous blood and arterial blood was attained within 50 min of the start of the infusion. The concentration of TOH in uterine and foetal tissue and in foetal blood water was the same as that in uterine venous water by 40 min; at this time, the concentration of TOH in the water of amniotic and allantoic fluids was 96% of that in uterine venous blood water. Estimates of total uterine blood flow obtained using TOH were highly correlated with those obtained with microspheres and the corresponding mean flow values obtained with the two techniques did not significantly differ. The percentage of the total uterine blood flow passing through arteriovenous anastomoses ranged from 1.4 to 3.3%

  8. Effects of neuropeptide Y on regulation of blood flow rate in canine myocardium

    DEFF Research Database (Denmark)

    Svendsen, Jesper Hastrup; Sheikh, S P; Jørgensen, J

    1990-01-01

    The effect of neuropeptide Y (NPY) on tension development was examined in isolated canine coronary arteries, and the effects on local myocardial blood flow rate were studied in open-chest anesthetized dogs by the local 133Xe washout technique. By immunohistochemistry, numerous NPY-like immunoreac......The effect of neuropeptide Y (NPY) on tension development was examined in isolated canine coronary arteries, and the effects on local myocardial blood flow rate were studied in open-chest anesthetized dogs by the local 133Xe washout technique. By immunohistochemistry, numerous NPY......+. In contrast, intracoronary NPY (0.01-10 micrograms) induced a considerable degree of vasoconstriction; the reduction of blood flow rate was dose related, with a maximum reduction to 52% of control values. The effect of intracoronary NPY (1 microgram) on maximally relaxed arterioles elicited by 30 s...... of ischemia was studied in separate experiments during reactive hyperemia. NPY induced a decrease in maximum blood flow during reactive hyperemia (166.6 vs. 214.6% of preocclusive blood flow rate, mean values; P = 0.05), an increase in the cumulative excess blood flow (61.0 vs. 35.3 ml/100 g; P = 0...

  9. Aortic blood flow subtraction: an alternative method for measuring total renal blood flow in conscious dogs

    DEFF Research Database (Denmark)

    Sandgaard, N C F; Andersen, J L; Holstein-Rathlou, N-H

    2002-01-01

    We have measured total renal blood flow (TRBF) as the difference between signals from ultrasound flow probes implanted around the aorta above and below the renal arteries. The repeatability of the method was investigated by repeated, continuous infusions of angiotensin II and endothelin-1 seven...... arterial blood pressure by 49% and decreased TRBF by 12%, providing an increase in renal vascular resistance of 69%. Dynamic analysis showed autoregulation of renal blood flow in the frequency range ... of TRBF by aortic blood flow subtraction is a practical and reliable method that allows direct comparison of excretory function and renal blood flow from two kidneys. The method also allows direct comparison between TRBF and flow in the caudal aorta....

  10. Relationship between coronary contrast-flow quantitative flow ratio and myocardial ischemia assessed by SPECT MPI

    Energy Technology Data Exchange (ETDEWEB)

    Smit, Jeff M.; Rosendael, Alexander R. van; Jukema, J.W.; Delgado, Victoria; Bax, Jeroen J.; Scholte, Arthur J. [Leiden University Medical Center, Department of Cardiology, Leiden (Netherlands); Koning, Gerhard [Medis Medical Imaging Systems B.V., Leiden (Netherlands); Dibbets-Schneider, Petra [Leiden University Medical Center, Department of Nuclear Medicine, Leiden (Netherlands); Mertens, Bart J. [Leiden University Medical Center, Department of Medical Statistics, Leiden (Netherlands); Reiber, Johan H.C. [Medis Medical Imaging Systems B.V., Leiden (Netherlands); Leiden University Medical Center, Department of Radiology, Leiden (Netherlands)

    2017-10-15

    A new method has been developed to calculate fractional flow reserve (FFR) from invasive coronary angiography, the so-called ''contrast-flow quantitative flow ratio (cQFR)''. Recently, cQFR was compared to invasive FFR in intermediate coronary lesions showing an overall diagnostic accuracy of 85%. The purpose of this study was to investigate the relationship between cQFR and myocardial ischemia assessed by single-photon emission computed tomography myocardial perfusion imaging (SPECT MPI). Patients who underwent SPECT MPI and coronary angiography within 3 months were included. The cQFR computation was performed offline, using dedicated software. The cQFR computation was based on 3-dimensional quantitative coronary angiography (QCA) and computational fluid dynamics. The standard 17-segment model was used to determine the vascular territories. Myocardial ischemia was defined as a summed difference score ≥2 in a vascular territory. A cQFR of ≤0.80 was considered abnormal. Two hundred and twenty-four coronary arteries were analysed in 85 patients. Overall accuracy of cQFR to detect ischemia on SPECT MPI was 90%. In multivariable analysis, cQFR was independently associated with ischemia on SPECT MPI (OR per 0.01 decrease of cQFR: 1.10; 95% CI 1.04-1.18, p = 0.002), whereas clinical and QCA parameters were not. Furthermore, cQFR showed incremental value for the detection of ischemia compared to clinical and QCA parameters (global chi square 48.7 to 62.6; p <0.001). A good relationship between cQFR and SPECT MPI was found. cQFR was independently associated with ischemia on SPECT MPI and showed incremental value to detect ischemia compared to clinical and QCA parameters. (orig.)

  11. Relationship Between Coronary Contrast-Flow Quantitative Flow Ratio and Myocardial Ischemia Assessed by SPECT MPI.

    Science.gov (United States)

    Smit, Jeff M; Koning, Gerhard; van Rosendael, Alexander R; Dibbets-Schneider, Petra; Mertens, Bart J; Jukema, J Wouter; Delgado, Victoria; Reiber, Johan H C; Bax, Jeroen J; Scholte, Arthur J

    2017-10-01

    A new method has been developed to calculate fractional flow reserve (FFR) from invasive coronary angiography, the so-called "contrast-flow quantitative flow ratio (cQFR)". Recently, cQFR was compared to invasive FFR in intermediate coronary lesions showing an overall diagnostic accuracy of 85%. The purpose of this study was to investigate the relationship between cQFR and myocardial ischemia assessed by single-photon emission computed tomography myocardial perfusion imaging (SPECT MPI). Patients who underwent SPECT MPI and coronary angiography within 3 months were included. The cQFR computation was performed offline, using dedicated software. The cQFR computation was based on 3-dimensional quantitative coronary angiography (QCA) and computational fluid dynamics. The standard 17-segment model was used to determine the vascular territories. Myocardial ischemia was defined as a summed difference score ≥2 in a vascular territory. A cQFR of ≤0.80 was considered abnormal. Two hundred and twenty-four coronary arteries were analysed in 85 patients. Overall accuracy of cQFR to detect ischemia on SPECT MPI was 90%. In multivariable analysis, cQFR was independently associated with ischemia on SPECT MPI (OR per 0.01 decrease of cQFR: 1.10; 95% CI 1.04-1.18, p = 0.002), whereas clinical and QCA parameters were not. Furthermore, cQFR showed incremental value for the detection of ischemia compared to clinical and QCA parameters (global chi square 48.7 to 62.6; p relationship between cQFR and SPECT MPI was found. cQFR was independently associated with ischemia on SPECT MPI and showed incremental value to detect ischemia compared to clinical and QCA parameters.

  12. Advanced 2-dimensional quantitative coronary angiographic analysis for prediction of fractional flow reserve in intermediate coronary stenoses.

    Science.gov (United States)

    Opolski, Maksymilian P; Pregowski, Jerzy; Kruk, Mariusz; Kepka, Cezary; Staruch, Adam D; Witkowski, Adam

    2014-07-01

    The widespread clinical application of coronary computed tomography angiography (CCTA) has resulted in increased referral patterns of patients with intermediate coronary stenoses to invasive coronary angiography. We evaluated the application of advanced quantitative coronary angiography (A-QCA) for predicting fractional flow reserve (FFR) in intermediate coronary lesions detected on CCTA. Fifty-six patients with 66 single intermediate coronary lesions (≥ 50% to 80% stenosis) on CCTA prospectively underwent coronary angiography and FFR. A-QCA including calculation of the Poiseuille-based index defined as the ratio of lesion length to the fourth power of the minimal lumen diameter (MLD) was performed. Significant stenosis was defined as FFR ≤ 0.80. The mean FFR was 0.86 ± 0.09, and 18 lesions (27%) were functionally significant. FFR correlated with lesion length (R=-0.303, P=0.013), MLD (R=0.527, P44%, and >69%, respectively (maximum negative predictive value of 94% for MLA, maximum positive predictive value of 58% for diameter stenosis). The Poiseuille-based index was the most accurate (C statistic 0.86, sensitivity 100%, specificity 71%, positive predictive value 56%, and negative predictive value 100%) predictor of FFR ≤ 0.80, but showed the lowest interobserver agreement (intraclass correlation coefficient 0.37). A-QCA might be used to rule out significant ischemia in intermediate stenoses detected by CCTA. The diagnostic application of the Poiseuille-based angiographic index is precluded by its high interobserver variability.

  13. Regional cerebral blood flow in schizophrenic patients

    International Nuclear Information System (INIS)

    Sagawa, Katsuo; Sibuya, Isoo; Oiji, Arata; Kawakatsu, Sinobu; Morinobu, Shigeru; Totsuka, Shiro; Kinoshita, Osami; Yazaki, Mitsuyasu.

    1990-01-01

    Seventy-six schizophrenic patients were examined by a Xe-133 inhalation method to determine regional cerebral blood flow. A decreased blood flow was observed in the frontal lobe, especially in the right inferior part. In a study on the relationship between disease subtypes and regional cerebral blood flow, negative symptoms were found more predominantly associated with dissolution type than delusion type. In the group of dissolution type, a decreased blood flow was observed in both the right inferior frontal lobe and the right upper hemisphere, in comparison to the group of delution type. Patients presenting with auditory hallucination had a significantly higher incidence of both negative and positive symptoms, as compared with those not presenting with it. In such patients, a significantly decreased blood flow was also seen in the left upper frontal lobe and the bilateral parietal lobe. Xe-133 inhalation method should assist in evaluating brain function in schizophrenic patients, thus leading to the likelihood of developing a new treatment modality. (N.K.)

  14. Coronary Flow Velocity Reserve Assessed by Transthoracic Doppler

    DEFF Research Database (Denmark)

    Michelsen, Marie M; Peña, Adam; Mygind, Naja D

    2016-01-01

    the feasibility and factors associated with the quality of CFVR obtained in a large prospective study of women suspected of having microvascular disease. METHODS: Women with angina-like chest pain and no obstructive coronary artery disease on coronary angiography (

  15. Fractional Flow Reserve-guided Percutaneous Coronary Intervention: Standing the Test of Time

    Directory of Open Access Journals (Sweden)

    Frederik M. Zimmermann, MD

    2016-05-01

    Full Text Available Percutaneous coronary intervention (PCI improves symptoms and prognosis in ischemia-inducing, functionally significant, coronary lesions. Use of fractional flow reserve allows physicians to investigate the ischemia-inducing potential of a specific lesion and can be used to guide coronary revascularization, especially in multivessel coronary artery disease. Fractional flow reserve-guided PCI has been extensively investigated. Results show that deferral of stenting in non-significant lesions is safe, whereas deferral of stenting in functionally significant lesions worsens outcome. FFR-guided PCI improves outcome in multivessel disease over angiography-guided PCI. Until recently, there was little known about the long-term outcome of FFR-guided revascularization and its validity in acute coronary syndromes. This review aims to address the new evidence regarding long-term appropriateness of FFR-guided PCI, the need for hyperemia to evaluate functional severity, and the use of FFR in acute coronary syndromes.

  16. In silico particle margination in blood flow

    OpenAIRE

    Müller, Kathrin

    2015-01-01

    A profound knowledge of margination, the migration of blood components to the vessel wall in blood flow, is required in order to understand the genesis of various diseases, as e.g., cardiovascular diseases or bleeding disorders. Margination of particles is a pre-condition for potential adhesion. Adhesion to the vessel wall is required for platelets, the protein von Willebrand factor (VWF), but also for drug and imaging agent carriers in order to perform their particular tasks. In the haemosta...

  17. The gated blood pool scan in the evaluation of coronary artery disease

    International Nuclear Information System (INIS)

    Anger, K.; Erbel, R.; Krebs, W.; Meyer, J.; Moeller, T.; Schweizer, P.; Yalkinoglu, O.; Technische Hochschule Aachen

    1983-01-01

    38 patients with clinically suspected coronary artery disease were studied by contrast ventriculography, 2-dimensional echocardiography and multiple gated blood pool imaging (MUGA) without stress. The results were compared with eath other and with the final diagnosis confirmed by coronary angiography. The left ventricular ejection fraction is evaluated nearly identically and with sufficient accuracy by both non-invasive methods, local motion abnormalities are on the other hand diagnosed in the best way by MUGA imaging in our own cases. (orig.) [de

  18. Electromechanical Model of Blood Flow in Vessels

    OpenAIRE

    Ivo Cap; Barbora Czippelova

    2008-01-01

    The present paper deals with some theoretical derivations connected with very efficient method of solution of hydrodynamic problems of blood flow in human cardiovascular system. The electromechanical analogy of liquid flow in a tube and electromagnetic wave propagating along an electric transmission line is discussed. We have derived a detailed circuit-like model of an elementary section of the elastic tube with viscose Newtonian liquid. The analogy harmonic current electrical cir...

  19. Electromechanical Model of Blood Flow in Vessels

    Directory of Open Access Journals (Sweden)

    Ivo Cap

    2008-01-01

    Full Text Available The present paper deals with some theoretical derivations connected with very efficient method of solution of hydrodynamic problems of blood flow in human cardiovascular system. The electromechanical analogy of liquid flow in a tube and electromagnetic wave propagating along an electric transmission line is discussed. We have derived a detailed circuit-like model of an elementary section of the elastic tube with viscose Newtonian liquid. The analogy harmonic current electrical circuit has been designed

  20. Cerebral blood flow response to functional activation

    DEFF Research Database (Denmark)

    Paulson, Olaf B; Hasselbalch, Steen G; Rostrup, Egill

    2010-01-01

    Cerebral blood flow (CBF) and cerebral metabolic rate are normally coupled, that is an increase in metabolic demand will lead to an increase in flow. However, during functional activation, CBF and glucose metabolism remain coupled as they increase in proportion, whereas oxygen metabolism only inc...... the cerebral tissue's increased demand for glucose supply during neural activation with recent evidence supporting a key function for astrocytes in rCBF regulation....

  1. Effect of decreased blood flow and ischemia on myocardial thallium clearance

    International Nuclear Information System (INIS)

    Okada, R.D.; Pohost, G.M.

    1984-01-01

    To determine the effect of reduced coronary blood flow on myocardial thallium-201 clearance over a range of flows, miniature radiation detectors were inserted into the left ventricular apex and positioned against the anterior and posterior endocardial walls in 21 dogs. Thallium was administered intravenously and myocardial tracer activity was monitored continuously for 1 hour in both walls. A balloon occluder was then partially inflated around the left anterior descending coronary artery in 19 dogs, producing a range of anterior wall blood flow reductions as assessed by the microsphere technique. Thallium activity was monitored continuously for 3 hours in both walls. Two dogs served as control animals and had no coronary artery occlusion at 1 hour. At the end of the 4 hour experiment, the dogs were sacrificed and the hearts counted in a well counter. The 19 dogs with coronary artery stenosis were divided into three groups (mild, moderate and severe flow reduction groups) on the basis of their poststenosis anterior/posterior wall regional myocardial blood flow ratios. The two control dogs had similar thallium clearances in the anterior and posterior left ventricular walls during the 3 hour period, as assessed by the radiation detectors, and by a final anterior/posterior wall thallium ratio near unity. All three groups of dogs with coronary stenosis had comparable fractional thallium clearances from the anterior and posterior walls before and after the balloon occluder inflation. The final anterior/posterior left ventricular wall thallium ratios were not significantly different than unity for all three groups of dogs

  2. Coronary flow response to remote ischemic preconditioning is preserved in old cardiac patients.

    Science.gov (United States)

    Santillo, Elpidio; Migale, Monica; Balestrini, Fabrizio; Postacchini, Demetrio; Bustacchini, Silvia; Lattanzio, Fabrizia; Antonelli-Incalzi, Raffaele

    2017-10-20

    The effect of remote ischemic preconditioning (RIPC) on coronary flow in elderly cardiac patients has not been investigated yet. Thus, we aimed to study the change of coronary flow subsequent to RIPC in old patients with heart diseases and to identify its main correlates. Ninety-five elderly patients (aged ≥ 65 years) accessing cardiac rehabilitation ward underwent transthoracic ultrasound evaluation of peak diastolic flow velocity of left anterior descending artery. Measurements of coronary flow velocity were performed on baseline and after an RIPC protocol (three cycles of 5 min ischemia of right arm alternating 5 min reperfusion). Differences between subjects with coronary flow velocity change over or equal the 75° percentile (high-responders) and subjects with a coronary flow velocity change under the 75° percentile (low-responders) were assessed. In enrolled elderly heart patients, coronary flow velocity significantly augmented from baseline after RIPC [0.23 m/s (0.18-0.28) vs 0.27 m/s (0.22-0.36); p < 0.001 by Wilcoxon test]. High-responders to RIPC were significantly younger and in better functional status than low-responders. Heart failure resulted as the main variable associated with impairment of RIPC responsiveness (R 2  = 0.202; p = 0.002)]. Our sample of old cardiac patients presented a significant median increment of coronary flow velocity after RIPC. The magnitude of the observed change of coronary flow velocity was comparable to that previously described in healthy subjects. The coronary response to RIPC was attenuated by heart failure. Further research should define whether such RIPC responsiveness is associated with cardioprotection and carries prognostic implications.

  3. MODELS OF MAJOR ADVERSE CARDIAC EVENT RISK USING RESULTS OF EXERCISE STRESS ECHOCARDIOGRAPHY WITH NONINVASIVE CORONARY ARTERY FLOW ASSESSMENT IN PATIENTS WITH ISCHEMIC HEART DISEASE

    Directory of Open Access Journals (Sweden)

    A. V. Zagatina

    2017-01-01

    Full Text Available Ultrasound non-invasive coronary artery imaging contributes to the diagnosis of ischemic heart disease (IHD in clinical practice. However, data of the prognostic value obtained from a complex analysis of contractility disorders and coronary blood flow parameters during exercise tests in the world literature are still not available. Aim. To develop risk models for adverse outcomes in patients with probable or definite IHD based on the results of a stress test with a noninvasive coronary blood flow study. Material and methods. Medical data of 689 patients with probable or definite IHD who underwent stress echocardiography with satisfactory visualization of the anterior interventricular artery (AIVA were included in the analysis. All patients had stress echocardiography on a horizontal bicycle ergometer. Registration of coronary blood flow in the middle third of the AIVA was performed at rest and at the peak of the load with calculation of the coronary reserve value. Further patient follow-up lasted 3 years. Models of further negative outcomes were developed on the basis of the stress echocardiography results and of coronary blood flow parameters. Results. Three models that take into account the factors associated with further mortality, mortality/myocardial infarction and sum of negative outcomes were developed in the study. These models divide a cohort of patients with probable or definite IHD into groups of low, medium and very high risks. Factors associated with the risk of death include: age >56 years, load power <100 W, breach of contractility in the blood supply zone of the circumflex artery initially and during exercise, the difference in blood flow velocities in the AIVA<10 cm/s, coronary reserve of AIVA<2. The risk model of death, taking into account these factors, suggests dividing patients into low-risk group if there are ≤2 factors (mortality 0.6% for 3 years, medium risk – from 2 to 4 factors (mortality 1.8%, high risk – ≥5

  4. Cerebral blood flow in acute mountain sickness

    DEFF Research Database (Denmark)

    Jensen, J B; Wright, Anne; Lassen, N A

    1990-01-01

    Changes in cerebral blood flow (CBF) were measured using the radioactive xenon technique and were related to the development of acute mountain sickness (AMS). In 12 subjects, ascending from 150 to 3,475 m, CBF was 24% increased at 24 h [45.1 to 55.9 initial slope index (ISI) units] and 4% increased...

  5. 3D flow study in a mildly stenotic coronary artery phantom using a whole volume PIV method.

    Science.gov (United States)

    Brunette, J; Mongrain, R; Laurier, J; Galaz, R; Tardif, J C

    2008-11-01

    Blood flow dynamics has an important role in atherosclerosis initiation, progression, plaque rupture and thrombosis eventually causing myocardial infarction. In particular, shear stress is involved in platelet activation, endothelium function and secondary flows have been proposed as possible variables in plaque erosion. In order to investigate these three-dimensional flow characteristics in the context of a mild stenotic coronary artery, a whole volume PIV method has been developed and applied to a scaled-up transparent phantom. Experimental three-dimensional velocity data was processed to estimate the 3D shear stress distributions and secondary flows within the flow volume. The results show that shear stress reaches values out of the normal and atheroprotective range at an early stage of the obstructive pathology and that important secondary flows are also initiated at an early stage of the disease. The results also support the concept of a vena contracta associated with the jet in the context of a coronary artery stenosis with the consequence of higher shear stresses in the post-stenotic region in the blood domain than at the vascular wall.

  6. Pulsatile spiral blood flow through arterial stenosis.

    Science.gov (United States)

    Linge, Fabian; Hye, Md Abdul; Paul, Manosh C

    2014-11-01

    Pulsatile spiral blood flow in a modelled three-dimensional arterial stenosis, with a 75% cross-sectional area reduction, is investigated by using numerical fluid dynamics. Two-equation k-ω model is used for the simulation of the transitional flow with Reynolds numbers 500 and 1000. It is found that the spiral component increases the static pressure in the vessel during the deceleration phase of the flow pulse. In addition, the spiral component reduces the turbulence intensity and wall shear stress found in the post-stenosis region of the vessel in the early stages of the flow pulse. Hence, the findings agree with the results of Stonebridge et al. (2004). In addition, the results of the effects of a spiral component on time-varying flow are presented and discussed along with the relevant pathological issues.

  7. Scaling of Myocardial Mass to Flow and Morphometry of Coronary Arteries

    OpenAIRE

    Choy, Jenny Susana; Kassab, Ghassan S.

    2008-01-01

    There is no doubt that scaling relations exist between myocardial mass and morphometry of coronary vasculature. The purpose of this study is to quantify several morphological (diameter, length, and volume) and functional (flow) parameters of the coronary arterial tree in relation to myocardial mass. Eight normal porcine hearts of 117-244 g (mean of 177.5±32.7) were used in this study. Various coronary sub-trees of the Left Anterior Descending (LAD), Right Coronary (RCA) and Left Circumflex (L...

  8. Fractional flow reserve versus angiography for guiding percutaneous coronary intervention in patients with multivessel coronary artery disease: 2-year follow-up of the FAME (Fractional Flow Reserve Versus Angiography for Multivessel Evaluation) study

    DEFF Research Database (Denmark)

    Pijls, Nico H J; Fearon, William F; Tonino, Pim A L

    2010-01-01

    The purpose of this study was to investigate the 2-year outcome of percutaneous coronary intervention (PCI) guided by fractional flow reserve (FFR) in patients with multivessel coronary artery disease (CAD)....

  9. Platelets and white blood cells in acute coronary syndromes

    NARCIS (Netherlands)

    Smit, Jaap Jan Johannes

    2008-01-01

    In this thesis, we have studied the role of leukocytes and platelets as methods to measure platelets aggregation, in the clinical management of presenting with acute coronary syndromes. We have tried to incidence and to identify predictors of adverse cardiac events with function tests or

  10. Comparative Study between Perfusion Changes and Positive Findings on Coronary Flow Reserve

    Directory of Open Access Journals (Sweden)

    Costantino Roberto Frack Costantini

    Full Text Available Abstract Background: Functional assessment of coronary artery obstruction is used in cardiology practice to correlate anatomic obstructions with flow decrease. Among such assessments, the study of the coronary fractional flow reserve (FFR has become the most widely used. Objective: To evaluate the correlation between FFR and findings of ischemia obtained by noninvasive methods including stress echocardiography and nuclear medicine and the presence of critical coronary artery obstruction. Methods: Retrospective study of cases treated with systematized and standardized procedures for coronary disease between March 2011 and August 2014. We included 96 patients with 107 critical coronary obstructions (> 50% in the coronary trunk and/or ≥ 70% in other segments estimated by quantitative coronary angiography (QCA and intracoronary ultrasound (ICUS. All cases presented ischemia in one of the noninvasive studies. Results: All 96 patients presented ischemia (100% in one of the functional tests. On FFR study with adenosine 140 g/kg/min, 52% of the cases had values ≤ 0.80. On correlation analysis for FFR ≤ 0.80, the evaluation of sensitivity, specificity, positive and negative predictive values, accuracy, and ROC curve in relation to the stenosis degree and length, and presence of ischemia, no significant values or strong correlation were observed. Conclusion: Coronary FFR using a cut-off value of 0.80 showed no correlation with noninvasive ischemia tests in patients with severe coronary artery obstructions on QCA and ICUS.

  11. Collision Based Blood Cell Distribution of the Blood Flow

    Science.gov (United States)

    Cinar, Yildirim

    2003-11-01

    Introduction: The goal of the study is the determination of the energy transferring process between colliding masses and the application of the results to the distribution of the cell, velocity and kinetic energy in arterial blood flow. Methods: Mathematical methods and models were used to explain the collision between two moving systems, and the distribution of linear momentum, rectilinear velocity, and kinetic energy in a collision. Results: According to decrease of mass of the second system, the velocity and momentum of constant mass of the first system are decreased, and linearly decreasing mass of the second system captures a larger amount of the kinetic energy and the rectilinear velocity of the collision system on a logarithmic scale. Discussion: The cause of concentration of blood cells at the center of blood flow an artery is not explained by Bernoulli principle alone but the kinetic energy and velocity distribution due to collision between the big mass of the arterial wall and the small mass of blood cells must be considered as well.

  12. Coronary diastolic pressure-flow relation and zero flow pressure explained on the basis of intramyocardial compliance

    NARCIS (Netherlands)

    Spaan, J. A.

    1985-01-01

    In the controversy about the mechanisms determining the high zero flow pressures and the further interpretation of coronary diastolic pressure flow relations, this paper takes a stand in favor of intramyocardial compliance as the primary cause of the high zero flow pressures. An attempt has been

  13. Ocular Blood Flow and Normal Tension Glaucoma

    Directory of Open Access Journals (Sweden)

    Ning Fan

    2015-01-01

    Full Text Available Normal tension glaucoma (NTG is known as a multifactorial optic neuropathy characterized by progressive retinal ganglion cell death and glaucomatous visual field loss, even though the intraocular pressure (IOP does not exceed the normal range. The pathophysiology of NTG remains largely undetermined. It is hypothesized that the abnormal ocular blood flow is involved in the pathogenesis of this disease. A number of evidences suggested that the vascular factors played a significant role in the development of NTG. In recent years, the new imaging techniques, fluorescein angiography, color Doppler imaging (CDI, magnetic resonance imaging (MRI, and laser speckle flowgraphy (LSFG, have been used to evaluate the ocular blood flow and blood vessels, and the impaired vascular autoregulation was found in patients with NTG. Previous studies showed that NTG was associated with a variety of systemic diseases, including migraine, Alzheimer’s disease, primary vascular dysregulation, and Flammer syndrome. The vascular factors were involved in these diseases. The mechanisms underlying the abnormal ocular blood flow in NTG are still not clear, but the risk factors for glaucomatous optic neuropathy likely included oxidative stress, vasospasm, and endothelial dysfunction.

  14. Cerebral blood flow changes in cluster headache

    International Nuclear Information System (INIS)

    Norris, J.W.; Hachinski, V.C.; Cooper, P.W.

    1976-01-01

    Serial cerebral blood flod studies performed by the intra-carotid 133 Xenon method were fortuitously determined during the course of a cluster headache in a 32 year old man. The initial study was performed about 10 min after the headache began and showed values at the upper limit of normal. Twenty min after the headache started a second procedure showed that the autoregulatory response on hyperventilation was normal. Ergotamine tartrate was given intra-muscularly 23 min after the headache began and there was partial relief. A third cerebral blood flow estimation showed abnormally high values. The probable reasons for this are discussed. (author)

  15. Patient-specific coronary blood supply territories for quantitative perfusion analysis

    Science.gov (United States)

    Zakkaroff, Constantine; Biglands, John D.; Greenwood, John P.; Plein, Sven; Boyle, Roger D.; Radjenovic, Aleksandra; Magee, Derek R.

    2018-01-01

    Abstract Myocardial perfusion imaging, coupled with quantitative perfusion analysis, provides an important diagnostic tool for the identification of ischaemic heart disease caused by coronary stenoses. The accurate mapping between coronary anatomy and under-perfused areas of the myocardium is important for diagnosis and treatment. However, in the absence of the actual coronary anatomy during the reporting of perfusion images, areas of ischaemia are allocated to a coronary territory based on a population-derived 17-segment (American Heart Association) AHA model of coronary blood supply. This work presents a solution for the fusion of 2D Magnetic Resonance (MR) myocardial perfusion images and 3D MR angiography data with the aim to improve the detection of ischaemic heart disease. The key contribution of this work is a novel method for the mediated spatiotemporal registration of perfusion and angiography data and a novel method for the calculation of patient-specific coronary supply territories. The registration method uses 4D cardiac MR cine series spanning the complete cardiac cycle in order to overcome the under-constrained nature of non-rigid slice-to-volume perfusion-to-angiography registration. This is achieved by separating out the deformable registration problem and solving it through phase-to-phase registration of the cine series. The use of patient-specific blood supply territories in quantitative perfusion analysis (instead of the population-based model of coronary blood supply) has the potential of increasing the accuracy of perfusion analysis. Quantitative perfusion analysis diagnostic accuracy evaluation with patient-specific territories against the AHA model demonstrates the value of the mediated spatiotemporal registration in the context of ischaemic heart disease diagnosis. PMID:29392098

  16. Cutaneous blood flow rate in areas with and without arteriovenous anastomoses during exercise

    DEFF Research Database (Denmark)

    Midttun, M.; Sejrsen, Per

    1998-01-01

    Arteriovenous anastomoses, capillaries, cutaneous bllod flow rate, exercise, finger blood flow, skin blood flow......Arteriovenous anastomoses, capillaries, cutaneous bllod flow rate, exercise, finger blood flow, skin blood flow...

  17. The relationship between fasting blood glucose variability and coronary artery collateral formation in type 2 diabetes patients with coronary artery disease.

    Science.gov (United States)

    Cheng, Gang; Mahmoudi, Hilda; Chokshi, Binna; Fernandez, Marlena; Kazemi, Vahid; Lamaa, Nader

    2017-09-01

    Coronary collaterals are an alternative source of blood supply to ischemic myocardium. Well-developed coronary collateral arteries in patients with coronary artery disease (CAD) limit the size of acute myocardial infarction and improves survival. The aim of this study was to investigate the relationship between glycemic variability and coronary collateral formation in patients with type 2 diabetes mellitus and CAD. Consecutive patients undergoing percutaneous coronary intervention or coronary artery bypass grafting procedures were studied. Multivariate logistic regression models were used to examine the association between coronary artery collateral formation graded by Rentrope classification and glycemic variability, measured by coefficient variation of fasting blood glucose. In our study, we retrospectively enrolled 300 patients, of whom 239 were diabetic (age: 70.1±11.9, 56% men) and 61 were nondiabetic (age: 71.5±11.5, 72% men). Diabetic patients were further stratified as follows: those with poor coronary collateral artery development (n=171, age: 69.7±12.4, 55% men) and those with good coronary collateral artery development (n=68, age 71.1±10.8, 59% men) according to the Rentrope classification. Our findings did not show association between glycemic variability and coronary collateral vessels development after controlling for potential confounders (odds ratio: 2.51; 95% confidence interval: 0.57-11.03; P=0.22). The culprit lesion (≥75% stenosis) in the left anterior descending artery and the right coronary artery was more frequent in the good collateral group compared with the poor collateral group (66 vs. 50%, P=0.02; 63 vs. 45%, P=0.01 respectively). Glycemic variability is not associated with coronary collateral artery formation in patients with type 2 diabetes mellitus and CAD.

  18. Blood-conservation techniques for coronary-artery bypass surgery at a private hospital.

    Science.gov (United States)

    Davies, M J; Picken, J; Buxton, B F; Fuller, J A

    1988-11-21

    The utilization of homologous blood and blood products was recorded in 100 consecutive patients who underwent primary coronary-artery bypass surgery. Nine patients underwent saphenous-vein grafts only, 55 patients underwent a single internal-mammary-artery graft that was supplemented by vein grafts and 36 patients underwent bilateral internal-mammary-artery grafts and vein grafts. All patients underwent normovolaemic haemodilution, and autologous blood was collected before bypass surgery. Residual blood was collected from the cardiopulmonary bypass machine and was washed and concentrated in a cell processor, and blood also was scavenged postoperatively from the mediastinal drainage tubes as methods to conserve blood. The mean (+/- SD) utilization of homologous blood was 1.3 +/- 1.5 units with 0.2 +/- 0.7 units of fresh-frozen plasma being used, and 0.8 +/- 2.1 units of platelets being used. The utilization of homologous blood was not different among the three different methods of coronary-artery bypass surgery, but patients who underwent bilateral internal-mammary-artery grafts suffered a greater postoperative loss of blood than did those patients who underwent saphenous-vein grafts or single internal-mammary-artery grafts. A comparison of patients who were taking aspirin or a non-steroidal anti-inflammatory drug preoperatively with those patients who were not showed no difference in the utilization of homologous blood but a statistically-significant difference was found in the loss of blood postoperatively.

  19. Determinants of pulmonary blood flow distribution.

    Science.gov (United States)

    Glenny, Robb W; Robertson, H Thomas

    2011-01-01

    The primary function of the pulmonary circulation is to deliver blood to the alveolar capillaries to exchange gases. Distributing blood over a vast surface area facilitates gas exchange, yet the pulmonary vascular tree must be constrained to fit within the thoracic cavity. In addition, pressures must remain low within the circulatory system to protect the thin alveolar capillary membranes that allow efficient gas exchange. The pulmonary circulation is engineered for these unique requirements and in turn these special attributes affect the spatial distribution of blood flow. As the largest organ in the body, the physical characteristics of the lung vary regionally, influencing the spatial distribution on large-, moderate-, and small-scale levels. © 2011 American Physiological Society.

  20. Regulation of bone blood flow in humans

    DEFF Research Database (Denmark)

    Heinonen, Ilkka; Boushel, Robert; Hellsten, Ylva

    2018-01-01

    of cyclooxygenase (COX) enzyme, thus prostaglandin (PG) synthesis on femoral bone marrow blood flow by positron emission tomography in healthy young men at rest and during one leg dynamic exercise. In an additional group of healthy men, the role of adenosine (ADO) in the regulation of BBF during exercise......The mechanisms that regulate bone blood flow (BBF) in humans are largely unknown. Animal studies suggest that nitric oxide (NO) could be involved and in the present study we investigated the effects of inhibition of nitric oxide synthase (NOS) alone and in combination with inhibition.......036), but did not affect BBF significantly during exercise (5.5±1.4 ml/100g/min, p=0.25). On the other hand, while combined NOS and COX inhibition did not cause any further reduction of blood flow at rest (0.6±0.2 ml/100g/min), the combined blockade reduced BBF during exercise by ~21%, to 5.0±1.8 ml/100g/min (p...

  1. Method of measuring blood flow by radiation

    International Nuclear Information System (INIS)

    Gildenberg, P.L.

    1977-01-01

    A method of measuring relative blood flow through at least a part of the body using penetrating radiation comprises transmitting a plurality of rays at an initial angle or initial mean angle through a planar slice of the body to define a first set of rays, transmitting a plurality of further sets of rays at angles or mean angles different from each other and from the initial angle or initial mean angle through the same planar slice of the body to define by the intersection of all such rays a two-dimensional matrix of elements of the body in the slice, measuring for each ray emerging from the body a number of over the period of time at least equal to a pulse interval representing the momentary sum of the transmissions or absorptions of the element of the body intersected by the ray, determining from the momentary signals momentary signals a difference signal representing the maximum difference between the momentary signals for each ray over the period of time, deriving sets of discrete difference signals corresponding to the sets of rays, the difference signals being indicative of the transmission or absorption of blood flowing through each element of the body in the matrix, and calculating from the difference signals resultant signals representing the transmissions or absorptions due to blood flow in the elements of the matrix. These resultant signals may be visually depicted on a cathode ray tube display, as a digital print-out, or as a photograph. 30 claims, 8 figures

  2. Regional cerebral blood flow in schizophrenia

    International Nuclear Information System (INIS)

    Kanoh, Masayuki

    1989-01-01

    Regional cerebral blood flow (rCBF) was measured at rest using the 133 Xe inhalation technique in 40 DSM-III-diagnosed schizophrenics (22 males, 18 females: mean age 35.0 years, range 20-49 years) and 31 age-and sex-matched normal controls (16 males, 15 females: mean age 34.3 years, range 21-49 years). The absolute value (AV) and the percent value (PV) of the rCBF in schizophrenics were compared with those in controls. Correlations between rCBF and the Brief Psychiatric Rating Scale (BPRS) scores or the performance of Wisconsin Card Sorting Test (WCST) were examined in schizophrenics. Schizophrenics showed significantly lower AVs in all brain regions examined and a significantly lower PV in the left superior frontal region than controls. The hyperfrontal rCBF distribution which was found in both hemispheres in controls, was absent in the left hemisphere in schizophrenics. In schizophrenics, superior frontal blood flows were significantly negatively correlated with the negative symptom scores of the BPRS but not with the total scores and the positive symptom scores of the BPRS. In schizophrenics, inferior frontal blood flows were significantly correlated with the number of sorting categories achieved. These results indicate that rCBF in schizophrenia is reduced in the whole brain and especially in the left superior frontal region. These findings suggest a frontal lobe dysfunction in schizophrenia. (author)

  3. Computational Analysis of Human Blood Flow

    Science.gov (United States)

    Panta, Yogendra; Marie, Hazel; Harvey, Mark

    2009-11-01

    Fluid flow modeling with commercially available computational fluid dynamics (CFD) software is widely used to visualize and predict physical phenomena related to various biological systems. In this presentation, a typical human aorta model was analyzed assuming the blood flow as laminar with complaint cardiac muscle wall boundaries. FLUENT, a commercially available finite volume software, coupled with Solidworks, a modeling software, was employed for the preprocessing, simulation and postprocessing of all the models.The analysis mainly consists of a fluid-dynamics analysis including a calculation of the velocity field and pressure distribution in the blood and a mechanical analysis of the deformation of the tissue and artery in terms of wall shear stress. A number of other models e.g. T branches, angle shaped were previously analyzed and compared their results for consistency for similar boundary conditions. The velocities, pressures and wall shear stress distributions achieved in all models were as expected given the similar boundary conditions. The three dimensional time dependent analysis of blood flow accounting the effect of body forces with a complaint boundary was also performed.

  4. Cerebral blood flow in Binswanger's disease

    International Nuclear Information System (INIS)

    Kawabata, Keita; Tachibana, Hisao; Sugita, Minoru

    1991-01-01

    Eight patients with a clinical diagnosis of Binswanger's disease (BD) were evaluated with I-123 IMP SPECT. The SPECT findings were compared with those in 7 other patients with Alzheimer's disease (AD) and 9 normal subjects. The ratios of I-123 IMP in the temporal cortex, thalamus, and basal ganglia to that in the cerebellum were lower in the BD group than the normal group. The BD group had a higher ratio of the occipital cortex/the cerebellum than the control group, suggesting a decreased blood flow in the cerebellum. When I-123 IMP ratio in various areas to that in the occipital cortex was examined, both the BD and AD groups seemed to have a decreased blood flow over the whole cerebrum. The BD group had a lower I-123 IMP uptake in the thalamus and basal ganglia, and the AD group had it in the parietal cortex, relative to the occipital cortex. Blood flow patterns for BD were found to be different from those for AD. This suggests the difference in areas responsible for etiology between BD and AD. (N.K.)

  5. Physiological importance of the coronary arterial blood supply to the rattlesnake heart

    DEFF Research Database (Denmark)

    Hagensen, Mette; Abe, Augusto S.; Falk, Erling

    2008-01-01

    Pa and 58.2±2.2 beats min-1, respectively, during activity and the ECG was not affected. This was not different from sham-operated snakes. Thus, while the outer compact layer of the rattlesnake heart clearly has an extensive coronary supply, rattlesnakes sustain a high blood pressure and heart rate during...

  6. Gender differences in regional cerebral blood flow

    International Nuclear Information System (INIS)

    Gur, R.E.; Gur, R.C.

    1990-01-01

    Gender differences have been noted in neurobehavioral studies. The 133xenon inhalation method for measuring regional cerebral blood flow (rCBF) can contribute to the understanding of the neural basis of gender differences in brain function. Few studies have examined gender differences in rCBF. In studies of normal subjects, women have higher rates of CBF than men, and this is related to age. Usually by the sixth decade men and women have similar flow rates. Fewer studies on rCBF in schizophrenia have examined sex differences. The pattern of higher flows for females maintains, but its correlates with gender differences in clinical as well as other parameters of brain function remain to be examined

  7. Nonlinear interactions in renal blood flow regulation

    DEFF Research Database (Denmark)

    Marsh, Donald J.; Sosnovtseva, Olga; Chon, Ki H.

    2005-01-01

    We have developed a model of tubuloglomerular feedback (TGF) and the myogenic mechanism in afferent arterioles to understand how the two mechanisms are coupled. This paper presents the model. The tubular model predicts pressure, flow, and NaCl concentration as functions of time and tubular length...... hydrostatic pressure, and plasma flow rate. The arteriolar model predicts fraction of open K channels, intracellular Ca concentration (Ca-i), potential difference, rate of actin - myosin cross bridge formation, force of contraction, and length of elastic elements, and was solved for two arteriolar segments...... resistance and glomerular capillary pressure. The model couples TGF input to voltage-gated Ca channels. It predicts autoregulation of GFR and renal blood flow, matches experimental measures of tubular pressure and macula densa NaCl concentration, and predicts TGF-induced oscillations and a faster smaller...

  8. Relationship between inter-arm blood pressure difference and severity of coronary atherosclerosis.

    Science.gov (United States)

    Park, Se-Jun; Son, Jung-Woo; Park, Sang-Min; Choi, Hyun-Hee; Hong, Kyung-Soon

    2017-08-01

    A greater inter-arm blood pressure difference (IABPD) is associated with atherosclerosis, but its association with coronary artery disease is unknown. We investigated the relationship between IABPD and coronary atherosclerosis. We retrospectively reviewed blood pressure (BP) data that was measured simultaneously in both arms of patients who underwent initial coronary angiography. Coronary atherosclerosis was assessed using the Gensini score, based on quantitative coronary angiography findings. To adjust for the effect of baseline BP, the percentages of systolic IABPD to higher mean BP (cIABPD sys ), diastolic IABPD to higher mean BP (cIABPD dia ), and mean IABPD to higher mean BP (cIABPD mean ) were calculated as BP-adjusted IABPDs. We examined the records of 816 patients (516 males, mean age: 65.5 ± 11.8 years). The mean Gensini score was 33.4 ± 30.4, and the median was 25. All cIAPBDs had positive correlations with the Gensini score (cIABPD sys : r = 0.208, p < 0.001; cIABPD dia : r = 0.123, p < 0.001; cIABPD mean : r = 0.120, p = 0.001). Multiple regression analysis indicated that cIABPD sys was associated with the Gensini score, independently of age, gender, smoking, diabetes, hypertension and dyslipidemia (B = 0.031, p < 0.001). The BP-adjusted IABPD parameters are related to the severity of coronary artery disease. Further studies should investigate the use of the IABPD to improve management of coronary atherosclerosis. Copyright © 2017. Published by Elsevier B.V.

  9. Regional cerebral blood flow in childhood headache

    International Nuclear Information System (INIS)

    Roach, E.S.; Stump, D.A.

    1989-01-01

    Regional cerebral blood flow (rCBF) was measured in 16 cranial regions in 23 children and adolescents with frequent headaches using the non-invasive Xenon-133 inhalation technique. Blood flow response to 5% carbon dioxide (CO2) was also determined in 21 patients, while response to 50% oxygen was measured in the two patients with hemoglobinopathy. Included were 10 patients with a clinical diagnosis of migraine, 4 with musculoskeletal headaches, and 3 with features of both types. Also studied were 2 patients with primary thrombocythemia, 2 patients with hemoglobinopathy and headaches, 1 patient with polycythemia, and 1 with headaches following trauma. With two exceptions, rCBF determinations were done during an asymptomatic period. Baseline rCBF values tended to be higher in these young patients than in young adults done in our laboratory. Localized reduction in the expected blood flow surge after CO2 inhalation, most often noted posteriorly, was seen in 8 of the 13 vascular headaches, but in none of the musculoskeletal headache group. Both patients with primary thrombocythemia had normal baseline flow values and altered responsiveness to CO2 similar to that seen in migraineurs; thus, the frequently reported headache and transient neurologic signs with primary thrombocythemia are probably not due to microvascular obstruction as previously suggested. These data support the concept of pediatric migraine as a disorder of vasomotor function and also add to our knowledge of normal rCBF values in younger patients. Demonstration of altered vasomotor reactivity to CO2 could prove helpful in children whose headache is atypical

  10. Simulation of blood flow in a small-diameter vascular graft model with a swirl (spiral) flow guider.

    Science.gov (United States)

    Zhang, ZhiGuo; Fan, YuBo; Deng, XiaoYan; Wang, GuiXue; Zhang, He; Guidoin, Robert

    2008-10-01

    Small-diameter vascular grafts are in large demand for coronary and peripheral bypass procedures, but present products still fail in long-term clinical application. In the present communication, a new type of small-diameter graft with a swirl flow guider was proposed to improve graft patency rate. Flow pattern in the graft was simulated numerically and compared with that in a conventional graft. The numerical results revealed that the swirl flow guider could indeed make the blood flow rotate in the new graft. The swirling flow distal to the flow guider significantly altered the flow pattern in the new graft and the velocity profiles were re-distributed. Due to the swirling flow, the blood velocity near the vessel wall and wall shear rate were greatly enhanced. We believe that the increased blood velocity near the wall and the wall shear rate can impede the occurrence of acute thrombus formation and intimal hyperplasia, hence can improve the graft patency rate for long-term clinical use.

  11. Feasibility and diagnostic power of transthoracic coronary Doppler for coronary flow velocity reserve in patients referred for myocardial perfusion imaging

    Directory of Open Access Journals (Sweden)

    Nylander Eva

    2008-03-01

    Full Text Available Abstract Background Myocardial perfusion imaging (MPI, using single photon emission computed tomography (SPECT is a validated method for detecting coronary artery disease. Transthoracic Doppler echocardiography (TTDE of flow at rest and during adenosine provocation has previously been evaluated in selected patient groups. We therefore wanted to compare the diagnostic ability of TTDE in the left anterior descending coronary artery (LAD to that of MPI in an unselected population of patients with chest pain referred for MPI. Our hypothesis was that TTDE with high accuracy would identify healthy individuals and exclude them from the need for further studies, enabling invasive investigations to be reserved for patients with a high probability of disease. Methods Sixty-nine patients, 44 men and 25 women, age 61 ± 10 years (range 35–82, with a clinical suspicion of stress induced myocardial ischemia, were investigated. TTDE was performed at rest and during adenosine stress for myocardial scintigraphy. Results We found that coronary flow velocity reserve (CFVR determined from diastolic measurements separated normal from abnormal MPI findings with statistical significance. TTDE identified coronary artery disease, defined from MPI, as reversible ischemia and/or permanent defect, with a sensitivity of 60% and a specificity of 79%. The positive predictive value was 43% and the negative predictive value was 88%. There was an overlap between groups which could be due to abnormal endothelial function in patients with normal myocardial perfusion having either hypertension or diabetes. Conclusion TTDE is an attractive non-invasive method to evaluate chest pain without the use of isotopes, but the diagnostic power is strongly dependent on the population investigated. Even in our heterogeneous clinical cardiac population, we found that CFVR>2 in the LAD excluded significant coronary artery disease detected by MPI.

  12. Glial and neuronal control of brain blood flow

    DEFF Research Database (Denmark)

    Attwell, David; Buchan, Alastair M; Charpak, Serge

    2010-01-01

    Blood flow in the brain is regulated by neurons and astrocytes. Knowledge of how these cells control blood flow is crucial for understanding how neural computation is powered, for interpreting functional imaging scans of brains, and for developing treatments for neurological disorders. It is now...... in our understanding of cerebral blood flow control have important implications for the development of new therapeutic approaches....

  13. Coronary flow reserve index corrected by exercise load using Tl-201 SPECT

    International Nuclear Information System (INIS)

    Kubota, Yasushi; Sugihara, Hiroki; Azuma, Akihiro

    1990-01-01

    For simple, non-invasive evaluation of coronary flow reserve during exercise, we investigated the coronary flow reserve index using the ratio of change of fractional distribution in the regional myocardium to oxygen demand. The subjects included 24 patients with effort angina pectoris and 11 normal volunteers. PTCA was peformed for 11 patients. Using the biological properties of Tl-201 single photon emission computed tomography (SPECT) was performed at submaximal exercise and at rest by two successive injections of Tl-201 within a short time interval (double dose method). The correlation between the fractional distribution in the myocardium (Δ-Fract) and the oxygen demand during exercise and at rest were evaluated. Δ-Fract correlated well with the rate of change of the pressure rate product (Δ-PRP), and Δ-Fract/Δ-PRP (CRI) was a good indicator of the coronary flow reserve index. CRI in the ischemic region correlated well with the percent area stenosis of the supplying coronary artery and improved with resolution of percent area stenosis of the target coronary artery after PTCA, but in some cases they were not above the normal range. CRI as obtained by exercise SPECT using the double dose method is useful for non-invasively estimating the coronary flow reserve during exercise, and it can be used for evaluating the effect before and after PTCA. (author)

  14. Improved assessment of functional severity of coronary artery stenosis by analysis of combined intracoronary pressure and flow velocity signals

    NARCIS (Netherlands)

    Nolte, F.

    2014-01-01

    Coronary artery disease (CAD) accounts for almost 2 million deaths per year within the EU. CAD is often characterized by focal narrowing of epicardial arteries, limiting coronary arterial flow and myocardial perfusion. Treatment of critical lesions by percutaneous coronary intervention (PCI) can be

  15. The effect of halothane on the distribution of cardiac output and organ blood flows in the hemorrhagic, hypotensive dog

    International Nuclear Information System (INIS)

    Ahlgren, I.; Aronsen, K.F.; Bjoerkman, I.

    1978-01-01

    Halothane was given to dogs which had been bled to an arterial mean blood pressure of 60 mmHg, and the circulatory effects were studied with the aid of the radioactive microsphere technique. The cardiac output and coronary blood flow were well maintained, whereas the arterial mean blood pressure was slightly, and the stroke volume markedly increased, indicating an improved heart function. The blood flows to the brain, lungs, liver and kidneys were well preserved throughout the anesthesia. The effect of retransfusing the withdrawn blood was also studied, and it resulted in an increased cardiac output, arterial mean blood pressure and increased blood flows to the heart, lungs, spleen, bowel and liver. (author)

  16. Model of the coronary circulation based on pressure dependence of coronary resistance and compliance

    NARCIS (Netherlands)

    Bruinsma, P.; Arts, T.; Dankelman, J.; Spaan, J. A.

    1988-01-01

    The effect of pressure-dependent changes in vascular volume, resistance and capacitance in the coronary micro-circulation, has been studied by a distributed mathematical model of the coronary micro-vasculature in the left ventricular wall. The model does not include regulation of coronary blood flow

  17. Regional cerebral blood flow in diabetic patients

    International Nuclear Information System (INIS)

    Nagamachi, Shigeki; Ono, Shinnichi; Nishikawa, Takushi

    1993-01-01

    N-isopropyl-p- 123 I-iodoamphetamine (IMP) was used to quantify the regional cerebral blood flow (r-CBF) in 11 diabetic patients (average age; 67.9 years) and 12 non-diabetic subjects (average age; 67.4 years), none of whom had (cerebrovascular disease (CVD) on CT studies. A reference sampling method by continuous arterial blood sampling was used to quantify r-CBF. There were no significant differences in physiological or laboratory data between diabetic and non-diabetic groups except for fasting plasma glucose and HbA 1c levels. The average of r-CBF in each region of cerebrum and cerebellum was significantly lower in diabetic group than that in the control group (p<0.01). These observations show that r-CBF of diabetic patients is reduced, even in the absence of findings of CVD on a CT study. (author)

  18. Coronary physiological assessment combining fractional flow reserve and index of microcirculatory resistance in patients undergoing elective percutaneous coronary intervention with grey zone fractional flow reserve.

    Science.gov (United States)

    Niida, Takayuki; Murai, Tadashi; Yonetsu, Taishi; Kanaji, Yoshihisa; Usui, Eisuke; Matsuda, Junji; Hoshino, Masahiro; Araki, Makoto; Yamaguchi, Masao; Hada, Masahiro; Ichijyo, Sadamitsu; Hamaya, Rikuta; Kanno, Yoshinori; Isobe, Mitsuaki; Kakuta, Tsunekazu

    2018-03-08

    The aim of this study is to investigate the association between fractional flow reserve (FFR) values and change in coronary physiological indices after elective percutaneous coronary intervention (PCI). Decision making for revascularization when FFR is 0.75-0.80 is controversial. A retrospective analysis was performed of 296 patients with stable angina pectoris who underwent physiological examinations before and after PCI. To investigate the differences of coronary flow improvement between territories with low-FFR (zone FFR (0.75-0.80), serial changes in physiological indices including mean transit time (Tmn), coronary flow reserve (CFR), and index of microcirculatory resistance (IMR) were compared between these two groups. Compared to low-FFR territories, grey-zone FFR territories showed significantly lower prevalence of Tmn shortening, CFR improvement, and decrease in IMR (Tmn shorting, 63.9% vs. 87.0%, P 51.3% vs. 63.3%, P = .040) and lower extent of their absolute changes (Tmn shorting, 0.06 (-0.03 to 0.16) vs. 0.22 (0.07-0.45), P zone FFR. Physiological assessment combining FFR and IMR may help identify patients who may benefit by PCI, particularly those in the grey zone. © 2018 Wiley Periodicals, Inc.

  19. Blood flow in healed and inflamed periodontal tissues of dogs

    Energy Technology Data Exchange (ETDEWEB)

    Hock, J.M.; Kim, S.

    1987-01-01

    The objectives of this study were to determine if increased blood flow associated with gingivitis would decrease following resolution of gingival inflammation in dogs with periodontitis; if increased blood flow in inflamed gingiva was associated with changes in the blood flow of alveolar bone, and if blood flow in gingiva and alveolar bone increased if periodontitis was reactivated by ligating teeth. Regional blood flow was measured in dogs with pre-existing periodontitis, using radioisotope-labelled, plastic microspheres. In the first experiment on 4 adult Beagle dogs, teeth in the left jaws were treated to resolve the periodontitis, while teeth in the right jaws were not treated. Gingival and bone blood flow were measured after 12 wk. Blood flow was significantly (p<0.05) lower in non-inflamed healed gingiva (32.1 +- 2.7 ml/min/100 g) than in inflamed gingiva (46.1 +- 5.3 ml/min/100 g). No differences in the blood flow of the alveolar bone underlying inflamed or non-inflamed gingiva were present. In the second experiment, the right mandibular teeth of 5 dogs were treated to resolve periodontitis while teeth in the other quadrants were ligated for 4, 10 or 12 wk. The duration of ligation did not alter blood flow. Gingival blood flow around ligated maxillary and mandibular teeth was comparable and approximately 54% higher than around non-ligated teeth (p<0.03). The difference in blood flow between gingiva with G.I.>1 and gingiva with G.I.<2 was significant (p<0.04). Blood flow in bone was not altered by changes in the inflammatory status of the overlying gingiva. The findings suggest that changes in blood flow associated with inflammation are reversible and that blood flow alveolar bone is regulated independently of gingival blood flow.

  20. Fractional Flow Reserve Assessment of a Significant Coronary Stenosis Masked by a Downstream Serial Lesion

    Directory of Open Access Journals (Sweden)

    Lawrence Yu-Min Liu

    2016-01-01

    Full Text Available Fractional flow reserve (FFR has been recognized as an effective tool to determine functional significance in intermediate coronary lesions and FFR-guided percutaneous coronary intervention (PCI improves clinical outcomes. However, hemodynamic interaction between serial stenoses within one coronary artery complicates the assessment of functional severity of each individual lesion. We present a case in which FFR measurement by intracoronary bolus injection of adenosine helps to make appropriate revascularization decision in serial stenoses when the procedures are performed systemically and properly.

  1. Role of blood flow and blood flow modifiers in clinical hyperthermia therapy

    International Nuclear Information System (INIS)

    Olch, A.J.

    1986-01-01

    A quantitative assessment of the effect of localized magnetic-loop hyperthermia on blood flow was performed on 12 patients (19 tumor studies) using the Xenon-133 clearance method. After it was discovered that blood flow in most of the tumors increased in response to needle injection, a physiologically based, one compartment model was developed that included both a hyperemic (transient) and a steady state component. In the tumors of six patients, increases in blood flow induced by heat were also observed. The same model was used to describe the measured clearance data for both types of hyperemic response. The ability of tumor vessels to respond dynamically to stress and the degree of response may be predictive of tumor heating efficiency and subsequent therapeutic response. Many tumors treated by hyperthermia, therefore, do not reach therapeutic temperatures (42 0 C). One explanation for this may be that some tumors react to thermal stress in a manner similar to normal tissues; i.e., they increase blood flow during hyperthermia in order to dissipate heat. Higher temperatures might be achieved in these heat-resistant tumors by administering vasoconstrictive agents in an effort to reduce blood flow. In the second part of this research study, the extent to which pharmacologic inhibition of local blood flow might allow higher temperatures to develop in normal muscles exposed to localized radiofrequency hyperthermia was determined. It was found that the local muscle temperature rise could be increased by at least 90% in dogs and rabbits with the use of a local vasoconstrictive drug

  2. The relationship between total arterial revascularization and blood transfusion following coronary artery bypass grafting.

    Science.gov (United States)

    Djordjevic, Jasmina; Ngaage, Dumbor L

    2015-05-01

    Blood transfusion adversely affects the outcome of coronary artery bypass grafting (CABG), yet blood transfusion after CABG is still common. Total arterial revascularisation (TAR) is increasingly used in current practice but its impact on postoperative blood transfusion is not known. We reviewed the cardiothoracic and blood bank databases and collected data for isolated primary CABG patients from July 2007 to June 2012, excluding patients who had a single graft (n = 148). Perioperative variables of TAR patients (n = 745) were compared with patients who had one or more venous grafts (SVG, n = 1,761) for first-time isolated CABG. The conduits used in TAR patients were predominantly left internal thoracic and radial arteries. Matched group comparison of TAR and SVG patients was performed. The association of TAR with blood transfusion was investigated using multivariate and matched analysis. Of 2,506 patients, the 745 (29.7 %) that had TAR were generally younger, with less complex coronary artery disease and less often diabetic. After correcting for these by 1:1 matching, the mean chest tube drainage and rates of blood transfusion remained significantly lower (p transfused in TAR patients. By multivariate analysis, TAR had an independent effect on reducing blood transfusion after CABG [odds ratio (OR) 0.67, 95 % confidence interval (CI) 0.47-0.97, p = .03]. TAR achieved predominantly with left internal thoracic and radial arteries substantially reduced blood transfusion rates after primary CABG. Further studies are warranted.

  3. Cerebral blood flow and metabolism during sleep

    DEFF Research Database (Denmark)

    Madsen, Peter Lund; Vorstrup, S

    1991-01-01

    A review of the current literature regarding sleep-induced changes in cerebral blood flow (CBF) and cerebral metabolic rate (CMR) is presented. Early investigations have led to the notion that dreamless sleep was characterized by global values of CBF and CMR practically at the level of wakefulness......, while rapid eye movement (REM) sleep (dream sleep) was a state characterized by a dramatically increased level of CBF and possibly also of CMR. However, recent investigations firmly contradict this notion. Investigations on CBF and CMR performed during non-REM sleep, taking the effect of different...... current state identify the physiological processes involved in sleep or the physiological role of sleep....

  4. Glial and neuronal control of brain blood flow

    DEFF Research Database (Denmark)

    Attwell, David; Buchan, Alastair M; Charpak, Serge

    2010-01-01

    Blood flow in the brain is regulated by neurons and astrocytes. Knowledge of how these cells control blood flow is crucial for understanding how neural computation is powered, for interpreting functional imaging scans of brains, and for developing treatments for neurological disorders. It is now...... recognized that neurotransmitter-mediated signalling has a key role in regulating cerebral blood flow, that much of this control is mediated by astrocytes, that oxygen modulates blood flow regulation, and that blood flow may be controlled by capillaries as well as by arterioles. These conceptual shifts...

  5. The effect of sympathectomy on bone blood flow in man

    International Nuclear Information System (INIS)

    Lahtinen, T.; Alhava, E.M.; Hyoedynmaa, S.; Hendolin, H.; Oksala, I.

    1982-01-01

    The effect of lumbar sympathectomy on bone blood flow was measured in seven patients with a Xe-133 washout method. On the third postoperative day there was a significant increase of blood flow in the proximal femur and a slight increase in the proximal tibia. Two months after the operation blood flow in the proximal part of the femur was no more significantly increased but in the proximal tibia there was a significant increase. The study suggests that the positive effect of sympathectomy on bone blood flow may be of value in cases where the increase of blood flow to peripheral bones is required

  6. Relationship between serum visfatin levels and coronary slow-flow phenomenon.

    Science.gov (United States)

    Cakmak, Huseyin Altug; Aslan, Serkan; Yalcin, Ahmet Arif; Akturk, Ibrahim Faruk; Yalcin, Burce; Uzun, Fatih; Ozturk, Derya; Erturk, Mehmet; Gul, Mehmet

    2015-09-01

    Increased levels of visfatin, a novel adipocytokine, are reported in atherosclerosis, obesity, and type 2 diabetes. The aim of the present study was to investigate the relationship between coronary slow flow (CSF) and visfatin in patients undergoing elective coronary angiography for suspected coronary artery disease. A total of 140 recruited participants (90 patients with CSF and 50 controls) were divided into two groups according to their coronary flow rates. Coronary flow was quantified by thrombolysis in myocardial infarction (TIMI) frame count (TFC). Serum visfatin levels were higher in the CSF group than in the control group (3.29 ± 1.11 vs. 2.70 ± 1.08 ng/ml, p = 0.003). A significant correlation was found between TFC and visfatin (r = 0.535, p < 0.001). The area under the receiver operating characteristic curve was 0.720 (95 % confidence interval, 0.622-0.817, p < 0.001) for visfatin in the diagnosis of CSF. If a cut-off value of 2.59 ng/ml was used, higher levels of visfatin could predict the presence of CSF with 78.9 % sensitivity and 64.0 % specificity. Visfatin levels might be a useful biomarker for predicting CSF in patients undergoing diagnostic coronary angiography.

  7. Blood flow in healed and inflamed periodontal tissues of dogs

    International Nuclear Information System (INIS)

    Hock, J.M.; Kim, S.

    1987-01-01

    The objectives of this study were to determine if increased blood flow associated with gingivitis would decrease following resolution of gingival inflammation in dogs with periodontitis; if increased blood flow in inflamed gingiva was associated with changes in the blood flow of alveolar bone, and if blood flow in gingiva and alveolar bone increased if periodontitis was reactivated by ligating teeth. Regional blood flow was measured in dogs with pre-existing periodontitis, using radioisotope-labelled, plastic microspheres. In the first experiment on 4 adult Beagle dogs, teeth in the left jaws were treated to resolve the periodontitis, while teeth in the right jaws were not treated. Gingival and bone blood flow were measured after 12 wk. Blood flow was significantly (p 1 and gingiva with G.I.<2 was significant (p<0.04). Blood flow in bone was not altered by changes in the inflammatory status of the overlying gingiva. The findings suggest that changes in blood flow associated with inflammation are reversible and that blood flow alveolar bone is regulated independently of gingival blood flow. (author)

  8. Creatine kinase and creatine kinase subunit-B in coronary sinus blood in pacing-induced angina pectoris

    DEFF Research Database (Denmark)

    Bagger, J P; Ingerslev, J; Heinsvig, E M

    1982-01-01

    In nine out of 10 patients with angiographic documented coronary artery disease, pacing-induced angina pectoris provoked myocardial production of lactate, whereas no significant release of either creatine kinase or creatine kinase subunit-B to coronary sinus and peripheral venous blood could...

  9. Regional cerebral blood flow in schizophrenics

    Energy Technology Data Exchange (ETDEWEB)

    Uchino, J.; Ohta, Y.; Nakane, Y.; Mori, H.; Hirota, N.; Yonekura, M.

    1987-01-01

    The present study on schizophrenics dealt with the relationship of regional cerebral blood flow (rCBF) to age, disease duration, and treatment length with chlorpromazine hydrochloride (CPZ). Regional cerebral blood flow in 28 cerebral regions of interest was measured by iv injection of /sup 133/X in 54 schizophrenic patients and 39 healthy volunteers. Neither age nor dosage of CPZ significantly influenced rCBF. All patients, including 11 treated for a short period of time (6 months or less), were characterized by having a decreased rCBF over the whole cerebrum. Thirty-four patients treated for a long period of time (2 years or more) had a varied rCBF distribution in the left hemisphere, with the most predominant feature being the decrease in rCBF in the frontal lobe (i.e., hypofrontality); however, there was no linear correlation between rCBF and disease duration. A decreased rCBE in the right occipital region was seen in patients with paranoid schizophrenia, suggesting that manifestations of symptoms may depend on disturbed regions. These results suggest that cerebral dysfunction in schizophrenic patients may not be restricted to the frontal lobe, but cover the whole cerebrum, and that nonuniform dysfunction in various regions of the cerebrum, including the frontal lobe, may be involved in manifestations of symptoms.

  10. Regional cerebral blood flow in schizophrenics

    International Nuclear Information System (INIS)

    Uchino, Jun; Ohta, Yasuyuki; Nakane, Yoshibumi; Mori, Hiroyuki; Hirota, Noriyoshi; Yonekura, Masahiro.

    1987-01-01

    The present study on schizophrenics dealt with the relationship of regional cerebral blood flow (rCBF) to age, disease duration, and treatment length with chlorpromazine hydrochloride (CPZ). Regional cerebral blood flow in 28 cerebral regions of interest was measured by iv injection of X-133 in 54 schizophrenic patients and 39 healthy volunteers. Neither age nor dosage of CPZ significantly influenced rCBF. All patients, including 11 treated for a short period of time (6 months or less), were characterized by having a decreased rCBF over the whole cerebrum. Thirty-four patients treated for a long period of time (2 years or more) had a varied rCBF distribution in the left hemisphere, with the most predominant feature being the decrease in rCBF in the frontal lobe (i.e., ''hypofrontality''); however, there was no linear correlation between rCBF and disease duration. A decreased rCBE in the right occipital region was seen in patients with paranoid schizophrenia, suggesting that manifestations of symptoms may depend on disturbed regions. These results suggest that cerebral dysfunction in schizophrenic patients may not be restricted to the frontal lobe, but cover the whole cerebrum, and that nonuniform dysfunction in various regions of the cerebrum, including the frontal lobe, may be involved in manifestations of symptoms. (Namekawa, K.)

  11. Regional blood flow in experimental myositis ossificans

    International Nuclear Information System (INIS)

    Hierton, C.

    1983-01-01

    In a recent model for heterotopic bone formation, muscular oedema, swelling and necrosis is seen in the quadriceps muscle of rabbit hind limbs immobilized for at least 2 weeks when, from the second week, the immobilized limb is subjected to dayly forcible mobilization lasting about 5 min. According to this model, heterotopic calcification develops gradually from the second week of forcible mobilization and is located in the vastus intermedius region. Between the fourth and fifth week of immobilization and forcible mobilization, heterotopic bone formation is seen in virtually all cases. The histological findings are similar to those in human ectopic bone formation. In the present investigation the labelled microsphere technique was used to study the regional blood flow effects in the early development of myositis ossificans with this model. The results are quite different from those reported by other investigators on immobilization alone and point to a causal relation between regional blood flow and forcible mobilization of the immobilized rabbit hind limp. Prostaglandins as mediators between the traumatic inflammation, a part of the circulatory effects observed and the induction of a new bone is suggested. (author)

  12. The Relationship Between the Gensini Score and Complete Blood Count Parameters in Coronary Artery Disease

    Directory of Open Access Journals (Sweden)

    Muhammet Raşit Sayın

    2012-08-01

    Full Text Available Introduction: The aim of this study was to evaluate the relationship between the extend andseverity of coronary artery disease (CAD determined by the Gensini score and complete bloodcount parameters (white blood cell, hemoglobin, platelet, mean platelet volume, lymphocyte,neutrophil.Patients and Methods: Ninety patients with CAD underwent coronary angiography (40 females,mean age 61 ± 1.2 years were included in this study. Patients with acute coronary syndrome andprior cardiovascular disease excluded from the study. The association between the extent andseverity of CAD, which were assessed by the Gensini score, and complete blood count parameterswas analyzed by a correlation analysis.Results: Coronary angiography revealed, 6 (6.7% patients had three, 16 (17.8% patients hadtwo, and 24 (26.7% patients had single-vessel disease; 44 (48.9% patients had non-criticalstenosis. The mean Gensini score was 19.1 ± 2.1. We found a relationship between white bloodcell and neutrophil counts and the Gensini score. There was no relationship between Gensiniscore and the mean platelet volume and other parameters.Conclusion: The present study supports the hypothesis that inflammation is one of the maincomponent in the pathogenesis of CAD.

  13. Posture changes and subfoveal choroidal blood flow.

    Science.gov (United States)

    Longo, Antonio; Geiser, Martial H; Riva, Charles E

    2004-02-01

    To evaluate the effect of posture change on subfoveal choroidal blood flow (ChBF) in normal volunteers. The pulsatile, nonpulsatile, and mean ChBF were measured with laser Doppler flowmetry in 11 healthy volunteers with a mean age of 32 +/- 13 (SD) years. The posture of the subjects was changed from standing (90 degrees ), to supine (-8 degrees ), and back to standing, with a mechanically driven table. During the whole experimental procedure, ChBF and heart rate (HR) were continuously recorded. After 30 seconds in standing position, the subjects were tilted to supine during approximately 30 seconds. They remained in this position for approximately 2 minutes, after which they were tilted back to the standing position (recovery), where they remained for another approximately 2 minutes. Systemic brachial artery blood pressure (BP) was measured in the baseline, supine, and recovery positions. This procedure was repeated to measure the intraocular pressure (IOP) at the different postures. Mean BP did not change significantly throughout the experimental procedure. As the body was tilted from standing to supine, HR decreased by 16% (P blood velocity. Based on previously reported experimental data that indicate that the ocular perfusion pressure increases less than predicted by purely hydrostatic considerations when the body is tilted from the standing to the supine position, the observed increase in ChBF suggests a passive response of the choroidal circulation to the posture change.

  14. Análise comparativa dos efeitos do diazepam, midazolam, propofol e etomidato na contratilidade miocárdica e no fluxo coronariano: estudo em corações isolados de ratos Effects of diazepam, midazolam, propofol and etomidate in myocardial contractility and coronary blood flow: comparative analysis in isolated rat's hearts

    Directory of Open Access Journals (Sweden)

    Carlos Geraldo Sobral de Medeiros

    2004-06-01

    Full Text Available OBJETIVO: Avaliar o efeito, na contratilidade miocárdica e no fluxo coronariano, de drogas comumente utilizadas na prática clínica (diazepam, midazolam, propofol e etomidato. MÉTODO: Foram estudados 50 corações isolados de ratos Wistar divididos em cinco grupos de dez, em preparação de Langendorff com líquido de perfusão de Krebs-Henseleit (K-H, mantendo-se constantes a pressão de perfusão (90 centímetros de água e a temperatura (37° + 0,5 graus Celsius. Com exceção do Grupo I (Controle, foram feitas infusões únicas, em um minuto, de diazepam (50 microgramas - Grupo II; midazolam (25 microgramas - Grupo III; propofol (25 e 50 microgramas - Grupo IV e etomidato (25 microgramas - Grupo V. Cada dose foi diluída e administrada em 0,1 mililitro de K-H, mantendo-se o fluxo e a pressão de perfusão coronarianos do sistema, durante sua infusão. Aferiu-se a freqüência cardíaca em batimentos por minuto (BPM, a tensão miocárdica em gramas (g, e o fluxo coronariano em mililitros por minuto (ml/min em 1, 3, 5, 10, 15, 20, 25 e 30 minutos; a contratilidade miocárdica foi avaliada pelo cálculo da primeira derivada tensão/tempo (dT/dtmax, naquelas marcas. RESULTADOS: A freqüência cardíaca apresentou variações nos Grupos I, III e IV. Em relação à tensão miocárdica, apenas o Grupo I não sofreu declínio; o fluxo coronariano, exceto no Grupo IV, apresentou variações para menos, ao longo do estudo; a contratilidade miocárdica decresceu em todos os grupos estudados, exceto no Grupo I. CONCLUSÃO: As drogas ensaiadas diminuíram a contratilidade miocárdica (p0,05.OBJECTIVE: The effects on myocardial contractility (dT/dtmax and coronary blood flow (CBF of common drugs used in clinical practice (diazepam, midazolam, propofol and etomidate were studied. METHOD: Fifty Wistar rat's hearts were divided into five groups of ten, and perfused by Langendorff method with Krebs-Henseleit solution (K-H, with the perfusion pressure

  15. Impact on early and late mortality after blood transfusion in coronary artery bypass graft surgery.

    Science.gov (United States)

    Santos, Antonio Alceu dos; Sousa, Alexandre Gonçalves; Thomé, Hugo Oliveira de Souza; Machado, Roberta Longo; Piotto, Raquel Ferrari

    2013-03-01

    To assess the 30-day and 1-year mortality associated to the red blood cell transfusion after coronary artery bypass grafting surgery. This procedure has been questioned by the international medical community, but it is still widely used in cardiac surgery. Therefore, it is needed more evidence of this medical practice in our country. We retrospectively analyzed 3,004 patients who underwent coronary artery bypass grafting surgery between June 2009 and July 2010. Patients were divided into two groups: non-transfused and transfused. The transfused group totaled 1,888 (63%) and non-transfused 1,116 (37%). There were 129 deaths in 30 days, with 108 (84%) in the transfused group and 21 (16%) in the non-transfused (Pconservation strategies should be encouraged to reduce blood products transfusions.

  16. Modeling microcirculatory blood flow: current state and future perspectives.

    Science.gov (United States)

    Gompper, Gerhard; Fedosov, Dmitry A

    2016-01-01

    Microvascular blood flow determines a number of important physiological processes of an organism in health and disease. Therefore, a detailed understanding of microvascular blood flow would significantly advance biophysical and biomedical research and its applications. Current developments in modeling of microcirculatory blood flow already allow to go beyond available experimental measurements and have a large potential to elucidate blood flow behavior in normal and diseased microvascular networks. There exist detailed models of blood flow on a single cell level as well as simplified models of the flow through microcirculatory networks, which are reviewed and discussed here. The combination of these models provides promising prospects for better understanding of blood flow behavior and transport properties locally as well as globally within large microvascular networks. © 2015 Wiley Periodicals, Inc.

  17. Association between blood cholesterol level with periodontal status of coronary heart disease patients

    Science.gov (United States)

    Valensia, Rosy; Masulili, Sri Lelyati C.; Lessang, Robert; Radi, Basuni

    2017-02-01

    Coronary heart disease (CHD) is an abnormal narrowing of heart arteries associated with local accumulation of lipids, in the form of cholesterol and triglycerides. Periodontal disease is a chronic inflammatory that suggests link to the development of CHD. In periodontitis have been reported changes in lipid profile, include increased of cholesterol levels of blood. Objective: to analyse correlation between blood cholesterol level with periodontal status of CHD and non CHD subjects. Methods: Periodontal status and blood cholesterol level of 60 CHD and 40 non CHD subjects was measured. Result: Blood cholesterol level in CHD subjects differs from non CHD subjects (p=0.032). Blood cholesterol level correlates with pocket depth (p=0.003) and clinical attachment loss (CAL) (p=0.000) in CHD subjects. Blood cholesterol level correlates with pocket depth (p=0.010) in non CHD subjects. There is no significant correlation between blood cholesterol level and bleeding on probing (BOP) in CHD subjects. There is no significant correlation between blood cholesterol level with BOP and CAL in non CHD subjects. Conclusion: Blood cholesterol level in control group is higher than CHD patients. Blood cholesterol level positively associated with pocket depth (r=0.375) and CAL (r=0.450) in CHD patients. Blood cholesterol level is positively associated with pocket depth (r=0.404) in control group.

  18. [Association between ABO blood groups and coronary heart disease in Chinese Guangxi Zhuang population].

    Science.gov (United States)

    Shi, Ying; Lin, Yingzhong; Liu, Hairun; Ji, Qingwei; Lu, Zhihong; Lu, Zhengde; Xu, Nengwen; Yuan, Jun; Liu, Ling

    2015-09-01

    To investigate this association between ABO blood groups and coronary heart disease (CHD) in the Chinese Guangxi Zhuang population. From August 2010 to April 2013, we performed a case-control study in a Chinese Zhuang population, which included 1 024 CHD cases and 1 024 age and gender-matched non-CHD controls. The ABO blood groups and biological variables were measured by standard laboratory procedures. The Gensini score was used to evaluate the severity of coronary artery stenosis. Compared to non-CHD control group, CHD group had higher levels of fasting blood glucose ((6.71 ± 6.72) mmol/L vs. (4.98 ± 1.55) mmol/L, P blood groups were associated with CHD risk in the Chinese Zhuang population. Compared with group O, the group B individuals had a higher risk of CHD (OR = 2.33, 95% CI 1.88-2.90, P group O subjects in the CHD group, and MACE at 1-year follow-up was similar between ABO blood groups of CHD individuals. ABO blood groups are associated with CHD risk in the Chinese Zhuang population.

  19. Blood omega-3 and trans fatty acids in middle-aged acute coronary syndrome patients.

    Science.gov (United States)

    Harris, William S; Reid, Kimberly J; Sands, Scott A; Spertus, John A

    2007-01-15

    We tested the hypothesis that lower blood omega-3 (omega-3) fatty acids (FAs) and/or higher trans FAs are associated with the risk of an acute coronary syndrome (ACS). Higher levels of omega-3 FA have been associated with decreased risk of sudden cardiac death. However, their association with ACS risk is unclear. Although higher self-reported intakes of trans FAs have been linked to increased coronary risk, the association between blood levels of trans FA and ACS risk is also unknown. We analyzed the FA composition of whole blood from 94 subjects with ACS and 94 age-, gender-, and race-matched controls. Omega-3 and trans FA associations with ACS were assessed using multivariable models after adjusting for smoking status, alcohol use, diabetes, body mass index, serum lipids, and history of myocardial infarction or revascularization. Subjects' mean age was 47 years, 54% were men, and 80% were Caucasian. Whole blood long-chain omega-3 FA (eicosapentaenoic acid [EPA] plus docosahexaenoic acid [DHA]) content was 29% lower in patients than in controls (1.7 +/- 0.9% vs 2.4 +/- 1.4%, p ACS, but higher blood trans FA content is not. Blood EPA + DHA may serve as a new, modifiable risk factor for ACS.

  20. Low cerebral blood flow in hypotensive perinatal distress

    DEFF Research Database (Denmark)

    Lou, H C; Lassen, N A; Friis-Hansen, B

    1977-01-01

    was used for the cerebral blood flow measurements. The study confirmed that perinatal distress may be associated with low arterial blood pressure, and it was shown that cerebral blood flow is very low, 20 ml/100 g/min or less, in hypotensive perinatal distress. It is concluded that cerebral ischaemia plays...... a crucial role in the development of perinatal hypoxic brain injury....

  1. Capillary pericytes regulate cerebral blood flow in health and disease

    DEFF Research Database (Denmark)

    Hall, Catherine N; Reynell, Clare; Gesslein, Bodil

    2014-01-01

    Increases in brain blood flow, evoked by neuronal activity, power neural computation and form the basis of BOLD (blood-oxygen-level-dependent) functional imaging. Whether blood flow is controlled solely by arteriole smooth muscle, or also by capillary pericytes, is controversial. We demonstrate t...

  2. Modified Beer-Lambert law for blood flow.

    Science.gov (United States)

    Baker, Wesley B; Parthasarathy, Ashwin B; Busch, David R; Mesquita, Rickson C; Greenberg, Joel H; Yodh, A G

    2014-11-01

    We develop and validate a Modified Beer-Lambert law for blood flow based on diffuse correlation spectroscopy (DCS) measurements. The new formulation enables blood flow monitoring from temporal intensity autocorrelation function data taken at single or multiple delay-times. Consequentially, the speed of the optical blood flow measurement can be substantially increased. The scheme facilitates blood flow monitoring of highly scattering tissues in geometries wherein light propagation is diffusive or non-diffusive, and it is particularly well-suited for utilization with pressure measurement paradigms that employ differential flow signals to reduce contributions of superficial tissues.

  3. Transthoracic Doppler echocardiography – noninvasive diagnostic window for coronary flow reserve assessment

    Directory of Open Access Journals (Sweden)

    Dimitrow Paweł

    2003-04-01

    Full Text Available Abstract This review focuses on transthoracic Doppler echocardiography as noninvasive method used to assess coronary flow reserve (CFR in a wide spectrum of clinical settings. Transthoracic Doppler echocardiography is rapidly gaining appreciation as popular tool to measure CFR both in stenosed and normal epicardial coronary arteries (predominantly in left anterior descending coronary artery. Post-stenotic CFR measurement is helpful in: functional assessment of moderate stenosis, detection of significant or critical stenosis, monitoring of restenosis after revascularization. In the absence of stenosis in the epicardial coronary artery, decreased CFR enable to detect impaired microvascular vasodilatation in: reperfused myocardial infarct, arterial hypertension with or without left ventricular hypertrophy, diabetes mellitus, hypercholesterolemia, syndrome X, hypertrophic cardiomyopathy. In these diseases, noninvasive transthoracic Doppler echocardiography allows for serial CFR evaluations to explore the effect of various pharmacological therapies.

  4. Fractional Flow Reserve Measurement by Coronary Computed Tomography Angiography: A Review with Future Directions

    Directory of Open Access Journals (Sweden)

    Asim Rizvi

    2016-12-01

    Full Text Available Invasive fractional flow reserve (FFR measurement is currently the gold standard for coronary intervention. FFR measurement by coronary computed tomography angiography (FFRCT is a novel and promising imaging technology that permits noninvasive assessment of physiologically significant coronary lesions. FFRCT is capable of combining the anatomic information provided by coronary computed tomography angiography with computational fluid dynamics to compute FFR. To date, several studies have reported the diagnostic performance of FFRCT compared with invasive FFR measurement as the reference standard. Further studies are now being implemented to determine the clinical feasibility and economic implications of FFRCT techniques. This article provides an overview and discusses the available evidence as well as potential future directions of FFRCT.

  5. Coronary Computed Tomographic Angiography-Derived Fractional Flow Reserve for Therapeutic Decision Making.

    Science.gov (United States)

    Tesche, Christian; Vliegenthart, Rozemarijn; Duguay, Taylor M; De Cecco, Carlo N; Albrecht, Moritz H; De Santis, Domenico; Langenbach, Marcel C; Varga-Szemes, Akos; Jacobs, Brian E; Jochheim, David; Baquet, Moritz; Bayer, Richard R; Litwin, Sheldon E; Hoffmann, Ellen; Steinberg, Daniel H; Schoepf, U Joseph

    2017-12-15

    This study investigated the performance of coronary computed tomography angiography (cCTA) with cCTA-derived fractional flow reserve (CT-FFR) compared with invasive coronary angiography (ICA) with fractional flow reserve (FFR) for therapeutic decision making in patients with suspected coronary artery disease (CAD). Seventy-four patients (62 ± 11 years, 62% men) with at least 1 coronary stenosis of ≥50% on clinically indicated dual-source cCTA, who had subsequently undergone ICA with FFR measurement, were retrospectively evaluated. CT-FFR values were computed using an on-site machine-learning algorithm to assess the functional significance of CAD. The therapeutic strategy (optimal medical therapy alone vs revascularization) and the appropriate revascularization procedure (percutaneous coronary intervention vs coronary artery bypass grafting) were selected using cCTA-CT-FFR. Thirty-six patients (49%) had a functionally significant CAD based on ICA-FFR. cCTA-CT-FFR correctly identified a functionally significant CAD and the need of revascularization in 35 of 36 patients (97%). When revascularization was deemed indicated, the same revascularization procedure (32 percutaneous coronary interventions and 3 coronary artery bypass grafting) was chosen in 35 of 35 patients (100%). Overall, identical management strategies were selected in 73 of the 74 patients (99%). cCTA-CT-FFR shows excellent performance to identify patients with and without the need for revascularization and to select the appropriate revascularization strategy. cCTA-CT-FFR as a noninvasive "one-stop shop" has the potential to change diagnostic workflows and to directly inform therapeutic decision making in patients with suspected CAD. Copyright © 2017 Elsevier Inc. All rights reserved.

  6. Computational model on pulsatile flow of blood through a tapered ...

    Indian Academy of Sciences (India)

    S PRIYADHARSHINI

    2017-11-02

    Nov 2, 2017 ... It is pertinent to note that the magnitudes of flow resistance are higher in the case of ... mathematical model on non-Newtonian flow of blood through a ..... The important predictions of the present investigation are enumerating the .... drug carriers for targeted drug delivery, reducing blood flow at the time of ...

  7. Small gliomas; Metabolism and blood flow

    Energy Technology Data Exchange (ETDEWEB)

    Tamura, Masaru; Shibasaki, Takashi; Horikoshi, Satoru; Ono, Nobuo; Zama, Akira; Kakegawa, Tohru; Ishiuchi, Shogo [Gunma Univ., Maebashi (Japan). School of Medicine

    1994-02-01

    Eight patients with small gliomas (6 low-grade and 2 high-grade) localized in a single gyrus or less than 2 cm diameter were investigated using positron tomography and single photon emission computed tomography. All three tumors examined demonstrated hypermetabolism of amino acids. High-grade gliomas demonstrated hypermetabolism of glucose and high blood flow, but normal or low oxygen metabolism. High-grade gliomas also showed accumulation of [sup 201]Tl chloride and high or low accumulation of [sup 123]I-isopropyl iodoamphetamine. These indications allow preoperative diagnosis of the malignancy of small gliomas, which is important because small gliomas with high-grade malignancy need more extensive removal and adjuvant therapy. (author).

  8. Cerebral blood flow in normal pressure hydrocephalus

    International Nuclear Information System (INIS)

    Mamo, H.L.; Meric, P.C.; Ponsin, J.C.; Rey, A.C.; Luft, A.G.; Seylaz, J.A.

    1987-01-01

    A xenon-133 method was used to measure cerebral blood flow (CBF) before and after cerebrospinal fluid (CSF) removal in patients with normal pressure hydrocephalus (NPH). Preliminary results suggested that shunting should be performed on patients whose CBF increased after CSF removal. There was a significant increase in CBF in patients with NPH, which was confirmed by the favorable outcome of 88% of patients shunted. The majority of patients with senile and presenile dementia showed a decrease or no change in CBF after CSF removal. It is suggested that although changes in CBF and clinical symptoms of NPH may have the same cause, i.e., changes in the cerebral intraparenchymal pressure, there is no simple direct relation between these two events. The mechanism underlying the loss of autoregulation observed in NPH is also discussed

  9. Cerebral blood flow variations in CNS lupus

    International Nuclear Information System (INIS)

    Kushner, M.J.; Tobin, M.; Fazekas, F.; Chawluk, J.; Jamieson, D.; Freundlich, B.; Grenell, S.; Freemen, L.; Reivich, M.

    1990-01-01

    We studied the patterns of cerebral blood flow (CBF), over time, in patients with systemic lupus erythematosus and varying neurologic manifestations including headache, stroke, psychosis, and encephalopathy. For 20 paired xenon-133 CBF measurements, CBF was normal during CNS remissions, regardless of the symptoms. CBF was significantly depressed during CNS exacerbations. The magnitude of change in CBF varied with the neurologic syndrome. CBF was least affected in patients with nonspecific symptoms such as headache or malaise, whereas patients with encephalopathy or psychosis exhibited the greatest reductions in CBF. In 1 patient with affective psychosis, without clinical or CT evidence of cerebral ischemia, serial SPECT studies showed resolution of multifocal cerebral perfusion defects which paralleled clinical recovery

  10. Quantitative measurement of the cerebral blood flow

    International Nuclear Information System (INIS)

    Houdart, R.; Mamo, H.; Meric, P.; Seylaz, J.

    1976-01-01

    The value of the cerebral blood flow measurement (CBF) is outlined, its limits are defined and some future prospects discussed. The xenon 133 brain clearance study is at present the most accurate quantitative method to evaluate the CBF in different regions of the brain simultaneously. The method and the progress it has led to in the physiological, physiopathological and therapeutic fields are described. The major disadvantage of the method is shown to be the need to puncture the internal carotid for each measurement. Prospects are discussed concerning methods derived from the same general principle but using a simpler, non-traumatic way to introduce the radio-tracer, either by breathing into the lungs or intraveinously [fr

  11. Effects of preoperative aspirin and clopidogrel therapy on perioperative blood loss and blood transfusion requirements in patients undergoing off-pump coronary artery bypass graft surgery.

    Science.gov (United States)

    Shim, Jae Kwang; Choi, Yong Seon; Oh, Young Jun; Bang, Sou Ouk; Yoo, Kyung Jong; Kwak, Young Lan

    2007-07-01

    Preoperative exposure to clopidogrel and aspirin significantly increases postoperative bleeding in patients undergoing on-pump coronary artery bypass graft surgery. Off-pump coronary bypass grafting has been proposed as an alternative technique to attenuate postoperative bleeding associated with clopidogrel. This study aimed to determine the effects of aspirin and clopidogrel therapy on perioperative blood loss and blood transfusion requirements in off-pump coronary artery bypass grafting. One hundred six patients scheduled for off-pump coronary artery bypass grafting were divided into three groups: aspirin and clopidogrel discontinued more than 6 days before surgery (group 1, n = 35), aspirin and clopidogrel continued until 3 to 5 days before surgery (group 2, n = 51), and both medications continued within 2 days of surgery (group 3, n = 20). Thromboelastographic tracings were analyzed before induction of anesthesia. Routine coagulation profiles were measured before and after surgery. A cell salvage device was used during surgery and salvaged blood was reinfused. Chest tube drainage and blood transfusion requirement were recorded postoperatively. Patient characteristics, operative data, and thromboelastographic tracings were similar among the groups. There were significant decreases in hematocrit level and platelet count and prolongation in prothrombin time postoperatively in all groups without any intergroup differences. The amounts of perioperative blood loss and blood transfusion required were all similar among the groups. Preoperative clopidogrel and aspirin exposure even within 2 days of surgery does not increase perioperative blood loss and blood transfusion requirements in patients undergoing elective off-pump coronary artery bypass grafting.

  12. Pooled comparison of regadenoson versus adenosine for measuring fractional flow reserve and coronary flow in the catheterization laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Stolker, Joshua M., E-mail: jstolker@yahoo.com [Mercy Heart and Vascular, 901 Patients First Drive, Washington, MO 63090 (United States); Saint Louis University, 3635 Vista Ave, St. Louis, MO 63110 (United States); Lim, Michael J., E-mail: limmj@slu.edu [Saint Louis University, 3635 Vista Ave, St. Louis, MO 63110 (United States); Shavelle, David M., E-mail: david.shavelle@med.usc.edu [University of Southern California, 1510 San Pablo St, Suite 322, Los Angeles, CA 90033 (United States); Morris, D. Lynn, E-mail: morrisdl@einstein.edu [Albert Einstein Medical Center, 5501 Old York Rd, Philadelphia, PA 19141 (United States); Angiolillo, Dominick J., E-mail: dominick.angiolillo@jax.ufl.edu [University of Florida Health-Jacksonville, 655 West 8th St, Jacksonville, FL 32209 (United States); Guzman, Luis A., E-mail: luis.guzman@jax.ufl.edu [University of Florida Health-Jacksonville, 655 West 8th St, Jacksonville, FL 32209 (United States); Kennedy, Kevin F., E-mail: kfkennedy@saint-lukes.org [Saint Luke' s Mid America Heart Institute, 4401 Wornall Road, Kansas City, MO 64111 (United States); Weber, Elizabeth, E-mail: eweber1@slu.edu [Saint Louis University, 3635 Vista Ave, St. Louis, MO 63110 (United States); Zareh, Meena, E-mail: meena.zareh@med.usc.edu [University of Southern California, 1510 San Pablo St, Suite 322, Los Angeles, CA 90033 (United States); Neumayr, Robert H., E-mail: robneumayr@gmail.com [Mercy Heart and Vascular, 901 Patients First Drive, Washington, MO 63090 (United States); Saint Louis University, 3635 Vista Ave, St. Louis, MO 63110 (United States); Zenni, Martin M., E-mail: martin.zenni@jax.ufl.edu [University of Florida Health-Jacksonville, 655 West 8th St, Jacksonville, FL 32209 (United States)

    2015-07-15

    Background: Adenosine is the gold standard for augmenting coronary flow during fractional flow reserve (FFR) testing of intermediate coronary stenoses. However, intravenous infusion is time-consuming and intracoronary injection is subject to variability. Regadenoson is a newer adenosine alternative administered as a single intravenous bolus during nuclear stress testing, but its efficacy and safety during FFR testing have been evaluated only in small, single-center studies. Methods: We pooled data from 5 academic hospitals, in which patients undergoing clinically-indicated FFR prospectively underwent comparison of intravenous adenosine infusion (140–175 mcg/kg/min) versus regadenoson bolus (400 mcg). Hemodynamics and symptoms with adenosine were recorded until maximal hyperemia occurred, and after returning to baseline hemodynamics, regadenoson was administered and monitoring was repeated. In a subset of patients with coronary flow data, average peak velocity (APV) at the distal flow sensor was recorded. Results: Of 149 patients enrolled, mean age was 59 ± 9 years, 76% were male, and 54% underwent testing of the left anterior descending artery. Mean adenosine-FFR and regadenoson-FFR were identical (0.82 ± 0.10) with excellent correlation of individual values (r = 0.96, p < 0.001) and no difference in patient-reported symptoms. Four patients (2.6%) had discrepancies between the 2 drugs for the clinical decision-making cutoff of FFR ≤ 0.80. Coronary flow responses to adenosine and regadenoson were similar (APV at maximal hyperemia 36 cm/s for both, p = 0.81). Conclusions: Regadenoson single-bolus administration has comparable FFR, symptoms, and coronary flow augmentation when compared with standard intravenous adenosine infusion. With its greater ease of administration, regadenoson may be a more “user-friendly” option for invasive ischemic testing.

  13. Impaired myocardial blood flow reserve in subjects with metabolic syndrome analyzed using positron emission tomography and N-13 labeled ammonia

    Energy Technology Data Exchange (ETDEWEB)

    Teragawa, Hiroki; Kihara, Yasuki [Hiroshima University Graduate School of Biomedical Sciences, Department of Cardiovascular Medicine, Hiroshima (Japan); Morita, Koichi; Tamaki, Nagara [Hokkaido University Graduate School of Medicine, Department of Nuclear Medicine, Sapporo (Japan); Shishido, Hiroki; Otsuka, Nobuaki; Hirokawa, Yutaka [Hiroshima Heiwa Clinic, Hiroshima (Japan); Chayama, Kazuaki [Hiroshima University Graduate School of Biomedical Sciences, Department of Molecular Science and Medicine, Hiroshima (Japan)

    2010-02-15

    Coronary vasomotor response might be impaired in metabolic syndrome (MS); however, the precise abnormality has not been elucidated. The aim of this study was to assess coronary-vasomotor response in MS subjects using N-13 labeled ammonia and positron emission tomography. Myocardial blood flow (MBF) was measured at rest and during adenosine infusion in MS subjects (n = 13, MS group) with no definite evidence of heart disease and in subjects without MS (n = 14, non-MS group). Coronary vascular resistance (CVR) was calculated by dividing the mean aortic blood pressure by MBF. Myocardial blood flow reserve (MFR) was calculated as the ratio of the MBF during adenosine infusion to that during rest. Blood chemical parameters were measured to evaluate their relationship with MFR. During adenosine infusion, MBF was lower (p = 0.0085) and CVR higher (p = 0.0128) in the MS group than in the non-MS group and MFR was significantly lower in the MS group than in the non-MS group (2.13 {+-} 0.99 vs. 3.38 {+-} 0.95, p = 0.0027). Multivariate analysis demonstrated that the homeostasis model assessment-insulin resistance (p < 0.05) and the presence of hypertension (p < 0.05) were independent determinants of MFR. The results indicate that MFR was impaired in MS subjects, suggesting that an abnormal coronary microvascular response occurred in these subjects. This abnormality may have been partially due to insulin resistance and hypertension. (orig.)

  14. Impaired myocardial blood flow reserve in subjects with metabolic syndrome analyzed using positron emission tomography and N-13 labeled ammonia

    International Nuclear Information System (INIS)

    Teragawa, Hiroki; Kihara, Yasuki; Morita, Koichi; Tamaki, Nagara; Shishido, Hiroki; Otsuka, Nobuaki; Hirokawa, Yutaka; Chayama, Kazuaki

    2010-01-01

    Coronary vasomotor response might be impaired in metabolic syndrome (MS); however, the precise abnormality has not been elucidated. The aim of this study was to assess coronary-vasomotor response in MS subjects using N-13 labeled ammonia and positron emission tomography. Myocardial blood flow (MBF) was measured at rest and during adenosine infusion in MS subjects (n = 13, MS group) with no definite evidence of heart disease and in subjects without MS (n = 14, non-MS group). Coronary vascular resistance (CVR) was calculated by dividing the mean aortic blood pressure by MBF. Myocardial blood flow reserve (MFR) was calculated as the ratio of the MBF during adenosine infusion to that during rest. Blood chemical parameters were measured to evaluate their relationship with MFR. During adenosine infusion, MBF was lower (p = 0.0085) and CVR higher (p = 0.0128) in the MS group than in the non-MS group and MFR was significantly lower in the MS group than in the non-MS group (2.13 ± 0.99 vs. 3.38 ± 0.95, p = 0.0027). Multivariate analysis demonstrated that the homeostasis model assessment-insulin resistance (p < 0.05) and the presence of hypertension (p < 0.05) were independent determinants of MFR. The results indicate that MFR was impaired in MS subjects, suggesting that an abnormal coronary microvascular response occurred in these subjects. This abnormality may have been partially due to insulin resistance and hypertension. (orig.)

  15. Cerebral blood flow simulations in realistic geometries

    Directory of Open Access Journals (Sweden)

    Szopos Marcela

    2012-04-01

    Full Text Available The aim of this work is to perform the computation of the blood flow in all the cerebral network, obtained from medical images as angiographies. We use free finite elements codes as FreeFEM++. We first test the code on analytical solutions in simplified geometries. Then, we study the influence of boundary conditions on the flow and we finally perform first computations on realistic meshes. L’objectif est ici de simuler l’écoulement sanguin dans tout le réseau cérébral (artériel et veineux obtenu à partir d’angiographies cérébrales 3D à l’aide de logiciels d’éléments finis libres, comme FreeFEM++. Nous menons d’abord une étude détaillée des résultats sur des solutions analytiques et l’influence des conditions limites à imposer dans des géométries simplifiées avant de travailler sur les maillages réalistes.

  16. Quantitative analysis of arterial flow properties for detection of non-calcified plaques in ECG-gated coronary CT angiography

    Science.gov (United States)

    Wei, Jun; Zhou, Chuan; Chan, Heang-Ping; Chughtai, Aamer; Agarwal, Prachi; Kuriakose, Jean; Hadjiiski, Lubomir; Patel, Smita; Kazerooni, Ella

    2015-03-01

    We are developing a computer-aided detection system to assist radiologists in detection of non-calcified plaques (NCPs) in coronary CT angiograms (cCTA). In this study, we performed quantitative analysis of arterial flow properties in each vessel branch and extracted flow information to differentiate the presence and absence of stenosis in a vessel segment. Under rest conditions, blood flow in a single vessel branch was assumed to follow Poiseuille's law. For a uniform pressure distribution, two quantitative flow features, the normalized arterial compliance per unit length (Cu) and the normalized volumetric flow (Q) along the vessel centerline, were calculated based on the parabolic Poiseuille solution. The flow features were evaluated for a two-class classification task to differentiate NCP candidates obtained by prescreening as true NCPs and false positives (FPs) in cCTA. For evaluation, a data set of 83 cCTA scans was retrospectively collected from 83 patient files with IRB approval. A total of 118 NCPs were identified by experienced cardiothoracic radiologists. The correlation between the two flow features was 0.32. The discriminatory ability of the flow features evaluated as the area under the ROC curve (AUC) was 0.65 for Cu and 0.63 for Q in comparison with AUCs of 0.56-0.69 from our previous luminal features. With stepwise LDA feature selection, volumetric flow (Q) was selected in addition to three other luminal features. With FROC analysis, the test results indicated a reduction of the FP rates to 3.14, 1.98, and 1.32 FPs/scan at sensitivities of 90%, 80%, and 70%, respectively. The study indicated that quantitative blood flow analysis has the potential to provide useful features for the detection of NCPs in cCTA.

  17. Renal blood flow in sepsis: a complex issue

    OpenAIRE

    Molitoris, Bruce A

    2005-01-01

    The clinical complexity of sepsis and the regional variability in renal blood flow present a difficult challenge for the clinician or investigator in understanding the role and clinical importance of reduced blood flow in the pathophysiology of sepsis-induced acute renal failure. Understanding the role of regional microvasculature flow and interactions between endothelium and white blood cells in the local delivery of oxygen and substrates is of critical importance. Therefore, measuring total...

  18. Regional cerebral blood flow in the patient with brain tumor

    International Nuclear Information System (INIS)

    Tsuchida, Shohei

    1993-01-01

    Regional cerebral blood flow (rCBF) was measured with xenon-enhanced CT (Xe-CT) in 21 cases of intracranial tumors (13 meningiomas, 5 gliomas, 3 metastatic brain tumors). Peritumoral edema was graded as mild, moderate or severe based on the extent of edema on CT and MRI. According to intratumoral blood flow distribution patterns, three patterns were classified as central type with relatively high blood flow at the center of the tumor, homogeneous type with an almost homogeneous blood flow distribution, and marginal type with relatively high blood flow at the periphery of the tumor. High grade astrocytoma and metastatic brain tumor showed marginal type blood flow and moderate or severe edema except in one case. Five meningiomas with severe peritumoral edema revealed marginal type blood flow and four with mild peritumoral edema showed central type blood flow, except for one case. No correlation was found between the extent of peritumoral edema and histological subtype, tumor size, location, duration of clinical history, vascularization on angiogram, and mean blood flow in the tumor. These results suggest that blood flow distribution patterns within the tumor may affect the extension of peritumoral edema. Pre- and postoperative rCBFs were evaluated with Xe-CT and IMP-SPECT in 7 cases, mean rCBF of peritumoral edema was 6.2 ml/100 g/min preoperatively, and discrepancy between rCBF on Xe-CT and that on IMP-SPECT was shown in the remote cortical region ipsilateral to the tumor. Postoperative rCBF revealed an improved blood flow in both adjacent and remote areas, suggesting that the decreased blood flow associated with brain tumors might be relieved after surgery. (author) 53 refs

  19. The effect of collateral flow and myocardial viability on the distribution of technetium-99m sestamibi in a closed-chest model of coronary occlusion and reperfusion

    International Nuclear Information System (INIS)

    Chareonthaitawee, P.; O'Connor, M.K.; Gibbons, R.J.; Christian, T.F.; Ritman, E.L.

    2000-01-01

    The objective of this study was to determine the effect of myocardial viability and the degree of collateral blood flow on the uptake and retention of 99m Tc-sestamibi by examining three animal models of coronary occlusion and reperfusion, each reflecting a different state of viability and collateral blood flow. Three closed-chest animal models were studied: canine (high collateral flow, preserved viability), porcine (low collateral flow, absent viability) and porcine with slowly occlusive coronary stents producing infarction and enhanced collateral blood flow (high collateral flow, absent viability). There were seven dogs, seven pigs and six pigs, respectively, in each animal model. Animals from all three models were subjected to a 40-min total left anterior descending artery (LAD) occlusion followed by 2 h of reperfusion. 99m Tc-sestamibi and radiolabelled microspheres were injected during LAD occlusion 10 min prior to reperfusion. Animals were sacrificed after 2 h of reperfusion flow. Ex situ heart slice imaging to determine risk area was followed by viability staining to determine infarct size. Slices were subsequently sectioned into equally sized radial segments and placed in a gamma well counter. Risk area as determined by ex situ 99m Tc-sestamibi imaging was not significantly different by model. Pathological infarct size differed significantly by model [canine = 1%±1% of the left ventricle (LV); porcine = 13%±8% LV; porcine with stent = 14%±7% LV; P=0.002]. Collateral blood flow by microspheres during occlusion tended to differ among models (overall P=0.08), with the canine and porcine with stent models having relatively high flow rates compared with the acute porcine model. 99m Tc-sestamibi activity correlated with microsphere blood flow in all three models, with r values for individual animals (n=20) ranging from 0.86 to 0.96 (all P 99m Tc-sestamibi uptake with myocardial blood flow. 99m Tc-sestamibi uptake overestimated blood flow to a greater extent

  20. Coronary Anomaly and Coronary Artery Fistula as Cause of Angina Pectoris with Literature Review

    Directory of Open Access Journals (Sweden)

    Jayanth Koneru

    2011-01-01

    Full Text Available Coronary artery fistulas are rare anomalies of the coronary arteries that may sometimes cause symptoms by shunting blood flow away from the myocardial capillary network. We report the case of a 46-year old lady which shows the right coronary cusp giving rise to left main coronary artery called anomalous origin of a coronary artery (AOCA, and also a fistula between the left coronary artery and pulmonary artery. We describe our diagnostic approach and review the literature on the epidemiology, pathophysiology, the diagnostic modalities, and treatment options.

  1. Assessment of hand blood flow: a modified technique

    International Nuclear Information System (INIS)

    Kirsh, J.C.; Tepperman, P.S.

    1985-01-01

    A blood flow artifact has been identified with the conventional bolus-injection technique in radionuclide studies of hand disorders. The artifact, consisting of increased blood flow on the injected side, was demonstrated in 22 of 25 subjects. Using a modified injection technique to allow time for local blood flow to return to the basal state, the artifact could be eliminated in 19 of 23 additional subjects. Use of this simple protocol should help avoid misinterpretation of blood flow asymmetry in the assessment of hand disorders

  2. Effect of fluocinolone acetonide cream on human skin blood flow

    International Nuclear Information System (INIS)

    Chimoskey, J.E.; Holloway, A. Jr.; Flanagan, W.J.

    1975-01-01

    Blood flow rate was measured in the forearm skin of human subjects exposed to ultraviolet irradiation. Blood flow was determined by the 133 Xe disappearance technique 18 hr after ultraviolet (UV) irradiation with a Westinghouse RS sunlamp held 10 inches from the skin for 10 min. Ultraviolet irradiation caused skin blood flow to increase. Application of fluocinolone acetonide cream, 0.025 percent, 4 times in the 16 hr following UV irradiation had no effect on either control skin blood flow or the UV-induced hyperemia

  3. Bone blood flow after spinal paralysis in the rat

    International Nuclear Information System (INIS)

    Takahashi, H.; Yamamuro, T.; Okumura, H.; Kasai, R.; Tada, K.

    1990-01-01

    The goal of this study was to investigate the acute and chronic effects of paralysis induced by spinal cord section or sciatic neurotomy on bone blood flow in the rat. Regional bone blood flow was measured in the early stage with the hydrogen washout technique and the change of whole bone blood flow was measured in the early and the late stages with the radioactive microsphere technique. Four to 6 h after cordotomy at the level of the 13th thoracic vertebra, the regional bone blood flow in the denervated tibia increased significantly (p less than 0.01). After hemicordotomy with rhizotomy at the same level, the regional bone blood flow in the denervated tibia increased significantly (p less than 0.05) 6 h postoperatively. The whole bone blood flow in the denervated tibia had also increased significantly (p less than 0.05) at 6 h and at 4 and 12 weeks postoperatively. After sciatic neurotomy, the regional and the whole bone blood flow in the paralytic tibia did not change significantly. The present study demonstrated that monoplegic paralysis caused an increase in bone blood flow in the denervated hind limb from a very early stage. It was suggested that the spinal nervous system contributed to the control of bone blood flow

  4. Impact of competitive flow on wall shear stress in coronary surgery: computational fluid dynamics of a LIMA-LAD model.

    Science.gov (United States)

    Nordgaard, Håvard; Swillens, Abigail; Nordhaug, Dag; Kirkeby-Garstad, Idar; Van Loo, Denis; Vitale, Nicola; Segers, Patrick; Haaverstad, Rune; Lovstakken, Lasse

    2010-12-01

    Competitive flow from native coronary vessels is considered a major factor in the failure of coronary bypass grafts. However, the pathophysiological effects are not fully understood. Low and oscillatory wall shear stress (WSS) is known to induce endothelial dysfunction and vascular disease, like atherosclerosis and intimal hyperplasia. The aim was to investigate the impact of competitive flow on WSS in mammary artery bypass grafts. Using computational fluid dynamics, WSS was calculated in a left internal mammary artery (LIMA) graft to the left anterior descending artery in a three-dimensional in vivo porcine coronary artery bypass graft model. The following conditions were investigated: high competitive flow (non-significant coronary lesion), partial competitive flow (significant coronary lesion), and no competitive flow (totally occluded coronary vessel). Time-averaged WSS of LIMA at high, partial, and no competitive flow were 0.3-0.6, 0.6-3.0, and 0.9-3.0 Pa, respectively. Further, oscillatory WSS quantified as the oscillatory shear index (OSI) ranged from (maximum OSI = 0.5 equals zero net WSS) 0.15 to 0.35, OSI similar to the no competitive flow condition. Graft flow is highly dependent on the degree of competitive flow. High competitive flow was found to produce unfavourable WSS consistent with endothelial dysfunction and subsequent graft narrowing and failure. Partial competitive flow, however, may be better tolerated as it was found to be similar to the ideal condition of no competitive flow.

  5. A novel patient-specific model to compute coronary fractional flow reserve.

    Science.gov (United States)

    Kwon, Soon-Sung; Chung, Eui-Chul; Park, Jin-Seo; Kim, Gook-Tae; Kim, Jun-Woo; Kim, Keun-Hong; Shin, Eun-Seok; Shim, Eun Bo

    2014-09-01

    The fractional flow reserve (FFR) is a widely used clinical index to evaluate the functional severity of coronary stenosis. A computer simulation method based on patients' computed tomography (CT) data is a plausible non-invasive approach for computing the FFR. This method can provide a detailed solution for the stenosed coronary hemodynamics by coupling computational fluid dynamics (CFD) with the lumped parameter model (LPM) of the cardiovascular system. In this work, we have implemented a simple computational method to compute the FFR. As this method uses only coronary arteries for the CFD model and includes only the LPM of the coronary vascular system, it provides simpler boundary conditions for the coronary geometry and is computationally more efficient than existing approaches. To test the efficacy of this method, we simulated a three-dimensional straight vessel using CFD coupled with the LPM. The computed results were compared with those of the LPM. To validate this method in terms of clinically realistic geometry, a patient-specific model of stenosed coronary arteries was constructed from CT images, and the computed FFR was compared with clinically measured results. We evaluated the effect of a model aorta on the computed FFR and compared this with a model without the aorta. Computationally, the model without the aorta was more efficient than that with the aorta, reducing the CPU time required for computing a cardiac cycle to 43.4%. Copyright © 2014. Published by Elsevier Ltd.

  6. 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)

  7. Repeatability of fractional flow reserve despite variations in systemic and coronary hemodynamics

    NARCIS (Netherlands)

    Johnson, N.P.; Johnson, D.T.; Kirkeeide, R.L.; Berry, C.; de Bruyne, B.; Fearon, W.F.; Oldroyd, K.G.; Pijls, N.H.J.; Gould, K. Lance

    2015-01-01

    Objectives This study classified and quantified the variation in fractional flow reserve (FFR) due to fluctuations in systemic and coronary hemodynamics during intravenous adenosine infusion. Background Although FFR has become a key invasive tool to guide treatment, questions remain regarding its

  8. Data adaptive estimation of transversal blood flow velocities

    DEFF Research Database (Denmark)

    Pirnia, E.; Jakobsson, A.; Gudmundson, E.

    2014-01-01

    the transversal blood flow. In this paper, we propose a novel data-adaptive blood flow estimator exploiting this modulation scheme. Using realistic Field II simulations, the proposed estimator is shown to achieve a notable performance improvement as compared to current state-of-the-art techniques.......The examination of blood flow inside the body may yield important information about vascular anomalies, such as possible indications of, for example, stenosis. Current Medical ultrasound systems suffer from only allowing for measuring the blood flow velocity along the direction of irradiation......, posing natural difficulties due to the complex behaviour of blood flow, and due to the natural orientation of most blood vessels. Recently, a transversal modulation scheme was introduced to induce also an oscillation along the transversal direction, thereby allowing for the measurement of also...

  9. Daily rhythm of cerebral blood flow velocity

    Directory of Open Access Journals (Sweden)

    Spielman Arthur J

    2005-03-01

    Full Text Available Abstract Background CBFV (cerebral blood flow velocity is lower in the morning than in the afternoon and evening. Two hypotheses have been proposed to explain the time of day changes in CBFV: 1 CBFV changes are due to sleep-associated processes or 2 time of day changes in CBFV are due to an endogenous circadian rhythm independent of sleep. The aim of this study was to examine CBFV over 30 hours of sustained wakefulness to determine whether CBFV exhibits fluctuations associated with time of day. Methods Eleven subjects underwent a modified constant routine protocol. CBFV from the middle cerebral artery was monitored by chronic recording of Transcranial Doppler (TCD ultrasonography. Other variables included core body temperature (CBT, end-tidal carbon dioxide (EtCO2, blood pressure, and heart rate. Salivary dim light melatonin onset (DLMO served as a measure of endogenous circadian phase position. Results A non-linear multiple regression, cosine fit analysis revealed that both the CBT and CBFV rhythm fit a 24 hour rhythm (R2 = 0.62 and R2 = 0.68, respectively. Circadian phase position of CBT occurred at 6:05 am while CBFV occurred at 12:02 pm, revealing a six hour, or 90 degree difference between these two rhythms (t = 4.9, df = 10, p Conclusion In conclusion, time of day variations in CBFV have an approximately 24 hour rhythm under constant conditions, suggesting regulation by a circadian oscillator. The 90 degree-phase angle difference between the CBT and CBFV rhythms may help explain previous findings of lower CBFV values in the morning. The phase difference occurs at a time period during which cognitive performance decrements have been observed and when both cardiovascular and cerebrovascular events occur more frequently. The mechanisms underlying this phase angle difference require further exploration.

  10. Fractional Flow Reserve Assessment of a Coronary Artery Fistula

    Directory of Open Access Journals (Sweden)

    Joseph Petit

    2015-01-01

    Full Text Available A 63 y/o male with a past medical history of hypertension, chronic obstructive pulmonary disease, and obesity was admitted to an outside hospital for an abdominal incisional hernia repair and cholecystectomy. Post-operatively he developed shortness of breath (SOB and multiple runs of paroxysmal atrial fibrillation. A CT scan was negative for pulmonary embolism, but showed a left anterior descending (LAD coronary artery to main pulmonary artery (MPA fistula. He was transferred to our facility for further management.

  11. Relationship between two blood stasis syndromes and inflammatory factors in patients with acute coronary syndrome.

    Science.gov (United States)

    Ma, Cai-Yun; Liu, Jing-Hua; Liu, Jian-Xun; Shi, Da-Zhuo; Xu, Zhen-Ye; Wang, Shao-Ping; Jia, Min; Zhao, Fu-Hai; Jiang, Yue-Rong; Ma, Qin; Peng, Hong-Yu; Lu, Yuan; Zheng, Ze; Ren, Feng-Xue

    2017-11-01

    To investigate the relationship between inflammatory factors and two Chinese medicine (CM) syndrome types of qi stagnation and blood stasis (QSBS) and qi deficiency and blood stasis (QDBS) in patients with acute coronary syndrome (ACS). Sixty subjects with ACS, whose pathogenesis changes belongs to qi disturbance blood stasis syndrome, were divided into 2 groups: 30 in the QSBS group and 30 in the QDBS group. The comparative analysis on them was carried out through comparing general information, coronary angiography and inflammatory factors including intracellular adhesion molecule-1 (ICAM-1), chitinase-3-like protein 1 (YKL-40) and lipoprotein-associated phospholipase A2 (Lp-PLA2). Compared with the QSBS group, Lp-PLA2 and YKL-40 levels in the QDBS group showed no-significant difference (P>0.05); ICAM-1 was significantly higher in the QDBS group than in the QSBS group in the pathological processes of qi disturbance and blood stasis syndrome of ACS (Psyndrome typing of QSBS and QDBS, which provides a research direction for standardization research of CM syndrome types.

  12. Cerebellar blood flow in methylmercury poisoning (Minamata disease)

    Energy Technology Data Exchange (ETDEWEB)

    Itoh, K.; Korogi, Y.; Tomiguchi, S.; Takahashi, M. [Dept. of Radiology, Kumamoto University School of Medicine (Japan); Okajima, T. [Dept. of Neurology, Johnan Hospital, Maihara, Johnan-mochi (Japan); Sato, H. [Dept. of Neurology, Minamata City General Hospital and Medical Centre (Japan)

    2001-04-01

    We looked at regional cerebellar blood flow in patients with Minamata disease (MD) using technetium-99 m ethyl cysteinate dimer (99m-Tc-ECD). We carried out single-photon emission computed tomography (SPECT) on 15 patients with MD (eight men, seven women, aged 51-78 years, mean 70.5 years) and 11 control subjects (eight men, three women, aged 62-80 years, mean 72.5 years). Regional blood flow was measured in the superior, middle, and inferior portions of the cerebellar hemispheres, and the frontal, temporal and occipital cerebral lobes. The degree of cerebellar atrophy was assessed on MRI. There were significant differences in regional blood flow in all parts of the cerebellum between patients and control, but no significant decrease was observed in the cerebrum. Blood flow was lower in the inferior cerebellum than in the other parts. Even in patients without cerebellar atrophy, flow was significantly decreased regional blood flow in the inferior part. (orig.)

  13. Cerebellar blood flow in methylmercury poisoning (Minamata disease)

    International Nuclear Information System (INIS)

    Itoh, K.; Korogi, Y.; Tomiguchi, S.; Takahashi, M.; Okajima, T.; Sato, H.

    2001-01-01

    We looked at regional cerebellar blood flow in patients with Minamata disease (MD) using technetium-99 m ethyl cysteinate dimer (99m-Tc-ECD). We carried out single-photon emission computed tomography (SPECT) on 15 patients with MD (eight men, seven women, aged 51-78 years, mean 70.5 years) and 11 control subjects (eight men, three women, aged 62-80 years, mean 72.5 years). Regional blood flow was measured in the superior, middle, and inferior portions of the cerebellar hemispheres, and the frontal, temporal and occipital cerebral lobes. The degree of cerebellar atrophy was assessed on MRI. There were significant differences in regional blood flow in all parts of the cerebellum between patients and control, but no significant decrease was observed in the cerebrum. Blood flow was lower in the inferior cerebellum than in the other parts. Even in patients without cerebellar atrophy, flow was significantly decreased regional blood flow in the inferior part. (orig.)

  14. Stress Perfusion Coronary Flow Reserve Versus Cardiac Magnetic Resonance for Known or Suspected CAD.

    Science.gov (United States)

    Kato, Shingo; Saito, Naka; Nakachi, Tatsuya; Fukui, Kazuki; Iwasawa, Tae; Taguri, Masataka; Kosuge, Masami; Kimura, Kazuo

    2017-08-15

    Phase-contrast (PC) cine magnetic resonance imaging (MRI) of the coronary sinus is a noninvasive method to quantify coronary flow reserve (CFR). This study sought to compare the prognostic value of CFR by cardiac magnetic resonance (CMR) and stress perfusion CMR to predict major adverse cardiac events (MACE). Participants included 276 patients with known coronary artery disease (CAD) and 400 with suspected CAD. CFR was calculated as myocardial blood flow during adenosine triphosphate infusion divided by myocardial blood flow at rest using PC cine MRI of the coronary sinus. During a median follow-up of 2.3 years, 47 patients (7%) experienced MACE. Impaired CFR (10% ischemia on stress perfusion CMR were significantly associated with MACE in patients with known CAD (hazard ratio [HR]: 5.17 and HR: 5.10, respectively) and suspected CAD (HR: 14.16 and HR: 6.50, respectively). The area under the curve for predicting MACE was 0.773 for CFR and 0.731 for stress perfusion CMR (p = 0.58) for patients with known CAD, and 0.885 for CFR and 0.776 for stress perfusion CMR (p = 0.059) in the group with suspected CAD. In patients with known CAD, sensitivity, specificity, and positive and negative predictive values to predict MACE were 64%, 91%, 38%, and 97%, respectively, for CFR, and 82%, 59%, 15%, and 97%, respectively, for stress perfusion CMR. In the suspected CAD group, these values were 65%, 99%, 80%, and 97%, respectively, for CFR, and 72%, 83%, 22%, and 98%, respectively, for stress perfusion CMR. The predictive values of CFR and stress perfusion CMR for MACE were comparable in patients with known CAD. In patients with suspected CAD, CFR showed higher HRs and areas under the curve than stress perfusion CMR, suggesting that CFR assessment by PC cine MRI might provide better risk stratification for patients with suspected CAD. Copyright © 2017 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

  15. The effect of partial portal decompression on portal blood flow and effective hepatic blood flow in man: a prospective study.

    Science.gov (United States)

    Rosemurgy, A S; McAllister, E W; Godellas, C V; Goode, S E; Albrink, M H; Fabri, P J

    1995-12-01

    With the advent of transjugular intrahepatic porta-systemic stent shunt and the wider application of the surgically placed small diameter prosthetic H-graft portacaval shunt (HGPCS), partial portal decompression in the treatment of portal hypertension has received increased attention. The clinical results supporting the use of partial portal decompression are its low incidence of variceal rehemorrhage due to decreased portal pressures and its low rate of hepatic failure, possibly due to maintenance of blood flow to the liver. Surprisingly, nothing is known about changes in portal hemodynamics and effective hepatic blood flow following partial portal decompression. To prospectively evaluate changes in portal hemodynamics and effective hepatic blood flow brought about by partial portal decompression, the following were determined in seven patients undergoing HGPCS: intraoperative pre- and postshunt portal vein pressures and portal vein-inferior vena cava pressure gradients, intraoperative pre- and postshunt portal vein flow, and pre- and postoperative effective hepatic blood flow. With HGPCS, portal vein pressures and portal vein-inferior vena cava pressure gradients decreased significantly, although portal pressures remained above normal. In contrast to the significant decreases in portal pressures, portal vein blood flow and effective hepatic blood flow do not decrease significantly. Changes in portal vein pressures and portal vein-inferior vena cava pressure gradients are great when compared to changes in portal vein flow and effective hepatic blood flow. Reduction of portal hypertension with concomitant maintenance of hepatic blood flow may explain why hepatic dysfunction is avoided following partial portal decompression.

  16. A study of coronary artery rotational motion with dense scale-space optical flow in intravascular ultrasound

    Energy Technology Data Exchange (ETDEWEB)

    Danilouchkine, M G; Mastik, F; Steen, A F W van der [Department of Biomedical Engineering, Erasmus Medical Center, Ee2302, PO Box 2040, 3000 CA, Rotterdam (Netherlands)], E-mail: m.danilouchkine@ErasmusMC.nl, E-mail: f.mastik@ErasmusMC.nl, E-mail: a.vandersteen@ErasmusMC.nl

    2009-03-21

    This paper describes a novel method for estimating tissue motion in two-dimensional intravascular ultrasound (IVUS) images of a coronary artery. It is based on the classical Lukas-Kanade (LK) algorithm for optical flow (OF). The OF vector field quantifies the amount of misalignment between two consecutive frames in a sequence of images. From the theoretical standpoint, two fundamental improvements are proposed in this paper. First, using a simplified representation of the vessel wall as a medium with randomly distributed scatterers, it was shown that the OF equation satisfies the integral brightness conservation law. Second, a scale-space embedding for the OF equation was derived under the assumption of spatial consistency in IVUS acquisitions. The spatial coherence is equivalent to a locally affine motion model. The latter effectively captures and appropriately describes a complex deformation pattern of the coronary vessel wall under the varying physiological conditions (i.e. pulsatile blood pressure). The accuracy of OF tracking was estimated on the tissue-mimicking phantoms subjected to the controlled amount of angular deviation. Moreover, the performance of the classical LK and proposed approach was compared using the simulated IVUS images with an atherosclerotic lesion. The experimental results showed robust and reliable performance of up to 5{sup 0} of rotation, which is within the plausible range of circumferential displacement of the coronary arteries. Subsequently, the algorithm was used to analyze vessel wall motion in 18 IVUS pullbacks from 16 patients. The in vivo experiments revealed that the motion of coronary arteries is primarily determined by the cardiac contraction.

  17. Regional cerebral blood flow in neuropediatrics

    International Nuclear Information System (INIS)

    Junik, R.

    2001-01-01

    Single photon emission computed tomography can effectively and non-invasively measure regional blood flow. Mostly used 99mTc-HMPAO is a safe brain imaging agent for pediatric applications. The radiation dose is acceptable. Knowledge of the normal rCBF pattern, including normal asymmetries and variations due to age, is necessary prerequisite for the evaluation and reporting of the results of 99mTc-HMPAO brain SPECT studies in clinical practice. The interpretation of he rCBF study in a child requires knowledge of normal brain maturation. The aim of the present review is to focus on the contribution to clinical developmental neurology of SPECT The clinical use of SPECT in developmental neurology are epilepsy, brain death, acute neurological loss including stroke, language disorders, cerebral palsy, high-risk neonates, hypertension due to renovascular disease, traumatic brain injury, migraine, anorexia nervosa, autism, Gilles de la Tourette syndrome, attention deficit disorder-hyperactivity, and monitoring therapy. Sedation is not routinely used, rather each child is evaluated. However, drug sedation is mandatory in some uncooperative children. (author)

  18. 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

  19. Blood flow velocity in migraine attacks - a transcranial Doppler study

    International Nuclear Information System (INIS)

    Zwetsloot, C.P.; Caekebeke, J.F.V.; Jansen, J.C.; Odink, J.; Ferrari, M.D.

    1991-01-01

    A pulsed Doppler device was used to measure blood flow velocities in the common carotid artery, the extracranial part of the internal carotid artery, the external carotid artery, the middle cerebral artery, and the anterior cerebral artery in 31 migraneurs without aura (n=27) and with aura (n=4), both during and ouside an attack. The aims were to compare blood flow velocity during and between migraine attacks and to study asymmetries of the blood flow velocity. Compared with blood flow velocity values obtained in the attack-free interval, blood flow velocity was lower during attacks without aura in both common carotid arteries, but not in the other extra- and intracranial vessels which were examined. However, during attacks of migraine with aura, blood flow velocity tended to be lower in all examined vessels. There were no asymmetries of the blood flow velocity. It is suggested that during migraine attacks without aura there is a dissociation in blood flow regulation in the common carotid and middle cerebral arteries. 20 refs., 2 tabs

  20. Subcutaneous blood flow during insulin-induced hypoglycaemia

    DEFF Research Database (Denmark)

    Hilsted, J; Madsbad, S; Sestoft, L

    1982-01-01

    Subcutaneous blood flow was measured preceding insulin-induced hypoglycaemia, at the onset of hypoglycaemic symptoms and 2 h later in juvenile diabetics with and without autonomic neuropathy and in normal males. In all groups subcutaneous blood flow decreased at the onset of hypoglycaemic symptom...

  1. Measurement of absolute bone blood flow by positron emission tomography

    Energy Technology Data Exchange (ETDEWEB)

    Nahmias, C.; Cockshott, W.P.; Garnett, E.S.; Belbeck, L.W.

    1986-03-01

    A method of measuring bone blood flow has been developed using /sup 18/F sodium fluoride and positron emission tomography. The blood flow levels are in line with those obtained experimentally from microsphere embolisation. This investigative method could be applied to elucidate a number of clinical questions involving bone perfusion.

  2. Modeling skin blood flow: a neuro-physiological approach

    NARCIS (Netherlands)

    Kingma, B.R.M.; Saris, W.H.M.; Frijns, A.J.H.; Steenhoven, van A.A.; Marken Lichtenbelt, van W.D.

    2010-01-01

    In humans skin blood flow (SBF) plays a major role in body heat loss. Therefore the accuracy of models ofhuman thermoregulation depends for a great deal on their ability to predict skin blood flow. Most SBFmodelsuse body temperatures directly for calculation of skin perfusion. However, humans do not

  3. Blood flow velocity in migraine attacks - a transcranial Doppler study

    Energy Technology Data Exchange (ETDEWEB)

    Zwetsloot, C.P.; Caekebeke, J.F.V.; Jansen, J.C.; Odink, J.; Ferrari, M.D. (Rijksuniversiteit Leiden (Netherlands))

    1991-05-01

    A pulsed Doppler device was used to measure blood flow velocities in the common carotid artery, the extracranial part of the internal carotid artery, the external carotid artery, the middle cerebral artery, and the anterior cerebral artery in 31 migraneurs without aura (n=27) and with aura (n=4), both during and ouside an attack. The aims were to compare blood flow velocity during and between migraine attacks and to study asymmetries of the blood flow velocity. Compared with blood flow velocity values obtained in the attack-free interval, blood flow velocity was lower during attacks without aura in both common carotid arteries, but not in the other extra- and intracranial vessels which were examined. However, during attacks of migraine with aura, blood flow velocity tended to be lower in all examined vessels. There were no asymmetries of the blood flow velocity. It is suggested that during migraine attacks without aura there is a dissociation in blood flow regulation in the common carotid and middle cerebral arteries. 20 refs., 2 tabs.

  4. Self-separation of blood plasma from whole blood during the capillary flow in microchannel

    Science.gov (United States)

    Nunna, Bharath Babu; Zhuang, Shiqiang; Lee, Eon Soo

    2017-11-01

    Self-separation of blood plasma from whole blood in microchannels is of great importance due to the enormous range of applications in healthcare and diagnostics. Blood is a multiphase complex fluid, composed of cells suspended in blood plasma. RBCs are the suspended particles whose shape changes during the flow of blood. The primary constituents of blood are erythrocytes or red blood cells (RBCs), leukocytes or white blood cells (WBCs), thrombocytes or platelets and blood plasma. The existence of RBCs in blood makes the blood a non-Newtonian fluid. The current study of separation of blood plasma from whole blood during self-driven flows in a single microchannel without bifurcation, by enhancing the capillary effects. The change in the capillary effect results in a change in contact angle which directly influences the capillary flow. The flow velocity directly influences the net force acting on the RBCs and influence the separation process. The experiments are performed on the PDMS microchannels with different contact angles by altering the surface characteristics using plasma treatment. The change in the separation length is studied during the capillary flow of blood in microchannel. Bharath Babu Nunna is a researcher in mechanical engineering and implementing the novel and innovative technologies in the biomedical devices to enhance the sensitivity of the disease diagnosis.

  5. Hyperemic stenosis resistance index for evaluation of functional coronary lesion severity

    NARCIS (Netherlands)

    Meuwissen, Martijn; Siebes, Maria; Chamuleau, Steven A. J.; van Eck-Smit, Berthe L. F.; Koch, Karel T.; de Winter, Robbert J.; Tijssen, Jan G. P.; Spaan, Jos A. E.; Piek, Jan J.

    2002-01-01

    Background-Both coronary blood flow velocity reserve (CFVR) and myocardial fractional flow reserve (FFR) are used to evaluate the hemodynamic severity of coronary lesions. However, discordant results between CFVR and FFR have been observed in 25%, to 30% of intermediate coronary lesions. An index of

  6. Our experience of blood flow measurements using radioactive tracers

    International Nuclear Information System (INIS)

    Danet, Bernard.

    1974-01-01

    A critical study of blood flow measuring methods is proposed. After a review of the various diffusible and non-diffusible radioactive tracers and the corresponding detector systems, the principles which allow to measure blood flow from the data so obtained, are studied. There is a different principle of flow measurement for each type of tracer. The theory of flow measurement using non-diffusible tracers (human serum albumin labelled with 131 I or sup(99m)Tc, 113 In-labelled siderophiline) and its application to cardiac flow measurement are described first. Then the theory of flow measurement using diffusible tracers ( 133 Xe, 85 Kr) and its application to measurement of blood flow through tissues (muscles and kidney particularly) are described. A personal experience of this various flow measurements is reported. The results obtained, the difficulties encountered and the improvments proposed are developed [fr

  7. Mammary blood flow regulation in the nursing rabbit

    International Nuclear Information System (INIS)

    Katz, M.; Creasy, R.K.

    1984-01-01

    Cardiac output and mammary blood flow distribution prior to and after suckling were studied in 10 nursing rabbits by means of radionuclide-labeled microspheres. Suckling was followed by a 5.8% rise in cardiac output and a 20.4% rise in mammary blood flow. Determinations of intraglandular blood flow distribution have shown that there was a 43% increase in blood flow to the glands suckled from as compared to a 22.7% rise to the contralateral untouched glands and a 4.9% rise in the remainder of untouched glands. The conclusion is that a local mechanism may be involved in the regulation of mammary blood flow in the nursing rabbit

  8. DOES TRANEXAMIC ACID REDUCE BLOOD LOSS IN OFF-PUMP CORONARY ARTERY BYPASS?

    Directory of Open Access Journals (Sweden)

    A. Mehr-Aein

    2006-09-01

    Full Text Available Tranexamic acid is now used on a routine basis for on-pump coronary artery bypass grafting (CABG. We assessed the hemostatic effects of tranexamic acid to decrease bleeding tendency and transfusion requirements in patients undergoing off-pump coronary artery bypass surgery (OPCAB. A total of 66 patients were enrolled to elective OPCAB in a double-blind, prospective randomized study. Of these, 33 patients received tranexamic acid (15 mg/kg before the infusion of heparin and 15 mg/kg after protamin infusion, and 33 patients received only saline. Preoperative hematologic variables, postoperative bleeding and allogeneic transfusions were considered. D-dimer plasma levels were also evaluated to monitor the activation of fibrinolysis. Postoperative bleeding was significantly lower in the tranexamic acid group compared with the control group (320 ± 38 mL vs. 480 ± 75 mL at 12 hour, P < 0.001. The tranexamic acid group had significantly lesser need for allogeneic blood products (0.46 units/patients vs. 0.94 units/patients, P < 0.001. They had also lower post-operative D-dimer plasma levels. No postoperative thrombotic complications were observed in either group. The defective hemostasis occurs even in the OPCABG. Tranexamic acid effectively reduces postoperative blood loss and the need for allogeneic blood products after OPCAB is decreased.

  9. Thermographic venous blood flow characterization with external cooling stimulation

    Science.gov (United States)

    Saxena, Ashish; Ng, E. Y. K.; Raman, Vignesh

    2018-05-01

    Experimental characterization of blood flow in a human forearm is done with the application of continuous external cooling based active thermography method. Qualitative and quantitative detection of the blood vessel in a thermal image is done, along with the evaluation of blood vessel diameter, blood flow direction, and velocity in the target blood vessel. Subtraction based image manipulation is performed to enhance the feature contrast of the thermal image acquired after the removal of external cooling. To demonstrate the effect of occlusion diseases (obstruction), an external cuff based occlusion is applied after the removal of cooling and its effect on the skin rewarming is studied. Using external cooling, a transit time method based blood flow velocity estimation is done. From the results obtained, it is evident that an external cooling based active thermography method can be used to develop a diagnosis tool for superficial blood vessel diseases.

  10. Quantitative myocardial blood flow with Rubidium-82 PET

    DEFF Research Database (Denmark)

    Hagemann, Christoffer E; Ghotbi, Adam A; Kjær, Andreas

    2015-01-01

    Positron emission tomography (PET) allows assessment of myocardial blood flow in absolute terms (ml/min/g). Quantification of myocardial blood flow (MBF) and myocardial flow reserve (MFR) extend the scope of conventional semi-quantitative myocardial perfusion imaging (MPI): e.g. in 1) identificat......Positron emission tomography (PET) allows assessment of myocardial blood flow in absolute terms (ml/min/g). Quantification of myocardial blood flow (MBF) and myocardial flow reserve (MFR) extend the scope of conventional semi-quantitative myocardial perfusion imaging (MPI): e.g. in 1...... global MFR and major adverse cardiovascular events (MACE), and together with new diagnostic possibilities from measuring the longitudinal myocardial perfusion gradient, cardiac (82)Rb PET faces a promising clinical future. This article reviews current evidence on quantitative (82)Rb PET's ability...

  11. Analysis of digital subtraction angiography for estimating flow reserve in critical coronary artery stenosis

    International Nuclear Information System (INIS)

    Kotoku, Shinya; Matsuzaki, Masunori; Otani, Nozomi

    1988-01-01

    To assess the accuracy of digital subtraction angiography in evaluating coronary flow reserve in cases with critical coronary artery stenosis, time-density curves were obtained from digital subtraction coronary angiograms in the myocardial region of interest. Time to peak contrast (TPC) and time constant of the washout exponential curve (T) were measured in 14 patients with stable effort angina pectoris and critical one vessel lesion before and after percutaneous transluminal coronary angioplasty (PTCA). All patients had normal left ventricular ejection fraction (59±7%) and 201 Tl myocardial images at rest. The values of TPC and T were significantly shortened from 5.4±1.3 to 4.5±1.0 sec (p<0.02) and from 10.9±3.8 to 5.3±1.3 sec (p<0.001) after PTCA, respectively. However, in 9 patients TPC values were approximately the same before and after PTCA. In five experimental dogs with critical circumflex coronary artery stenosis, coronary flow (CF; Doppler flowmeter) and systolic thickening of the posterior wall (by sonomicrometry) at rest did not differ from those of the controls. However, contrast media-induced reactive hyperemia was markedly attenuated, accompanied by a significant increase in T (7.7±4.5 vs 15.8±10.9 sec, p<0.01) and totally unchanged TPC (both 6.8 sec). With simultaneous tracings of CF and time-density curves, TPC and washout phases corresponded with contrast-induced transient CF reduction and hyperemic phases, respectively. We concluded that T may be more sensitive for estimating CF maintained nearly normal, e.g., in patients with stable effort angina pectoris having normal left ventricular wall motion at rest. (author)

  12. Impact of the Absolute Difference in Diastolic Blood Pressure Between Arms in Patients With Coronary Artery Disease

    OpenAIRE

    Hitaka, Yuka; Miura, Shin-ichiro; Koyoshi, Rie; Shiga, Yuhei; Miyase, Yuiko; Norimatsu, Kenji; Nakamura, Ayumi; Adachi, Sen; Kuwano, Takashi; Sugihara, Makoto; Ike, Amane; Nishikawa, Hiroaki; Saku, Keijiro

    2015-01-01

    Background We investigated the relationship between the severity and presence of coronary artery disease (CAD) and a difference in systolic and diastolic blood pressure (SBP and DBP) between arms or between lower limbs. Methods We enrolled 277 patients who underwent coronary angiography. We calculated the absolute (|right BP (rt. BP) - left BP (lt. BP)|) and relative (rt. BP - lt. BP) differences in SBP or DBP between arms or between lower limbs, and assessed the severity of CAD in terms of t...

  13. Physiological assessment of coronary lesion severity: fractional flow reserve versus nonhyperaemic indices.

    Science.gov (United States)

    Robertson, Keith E; Hennigan, Barry; Berry, Colin; Oldroyd, Keith G

    2015-08-01

    Coronary angiography alone cannot accurately identify the haemodynamic impact of a coronary artery stenosis. Current international guidelines for myocardial revascularization recommend that inducible ischaemia should be demonstrated before the consideration of percutaneous coronary intervention. Invasive physiological assessment of coronary stenosis severity has increasingly been utilized for this purpose and use of the best validated technique, fractional flow reserve (FFR), has been shown to improve clinical outcomes in patients with stable and unstable coronary artery disease. This has led to the use of FFR being recommended in international revascularization guidelines, despite which, clinical uptake has been limited. One potential reason for slow adoption has been the requirement for maximal hyperaemia at the time of FFR measurement, usually achieved by the administration of pharmacological vasodilators such as adenosine. In some healthcare systems, adenosine is expensive and, in addition, its use can be associated with significant, albeit transient, adverse effects that patients (and some operators) find uncomfortable. Consequently, several methods of nonhyperaemic lesion assessment and their potential role in decision making have been reported. In this review we will review and discuss the current evidence for hyperaemic and nonhyperaemic methods of lesion assessment. We will also look at hybrid strategies that utilize both hyperaemic and nonhyperaemic methods as a means of potentially maintaining diagnostic accuracy while minimizing the requirement for adenosine administration and discuss whether or not they represent viable clinical alternatives.

  14. Effects of exercise training on coronary transport capacity

    International Nuclear Information System (INIS)

    Laughlin, M.H.

    1985-01-01

    Coronary transport capacity was estimated in eight sedentary control and eight exercise-trained anesthetized dogs by determining the differences between base line and the highest coronary blood flow and permeability-surface area product (PS) obtained during maximal adenosine vasodilation with coronary perfusion pressure constant. The anterior descending branch of the left coronary artery was cannulated and pump- perfused under constant-pressure conditions (approximately equal to 100 Torr) while aortic, central venous, and coronary perfusion pressures, heart rate, electrocardiogram, and coronary flow were monitored. Myocardial extraction and PS of 51 Cr-labeled ethylenediaminetetraacetic acid were determined with the single-injection indicator-diffusion method. The efficacy of the 16 +/- 1 wk exercise training program was shown by significant increases in the succinate dehydrogenase activities of the gastrocnemius, gluteus medialis, and long head of triceps brachii muscles. There were no differences between control and trained dogs for either resting coronary blood flow or PS. During maximal vasodilation with adenosine, the trained dogs had significantly lower perfusion pressures with constant flow and, with constant-pressure vasodilation, greater coronary blood flow and PS. It is concluded that exercise training in dogs induces an increased coronary transport capacity that includes increases in coronary blood flow capacity (26% of control) and capillary diffusion capacity (82% of control)

  15. Blood flow behavior in microchannels: past, current and future trends

    OpenAIRE

    Lima, R.; Ishikawa, Takuji; Imai, Yohsuke; Yamaguchi, Takami

    2012-01-01

    Over the years, various experimental methods have been applied in an effort to understand the blood flow behavior in microcirculation. Most of our current knowledge in microcirculation is based on macroscopic flow phenomena such as Fahraeus effect and Fahraeus-Linqvist effect. The development of optical experimental techniques has contributed to obtain possible explanations on the way the blood flows through microvessels. Although the past results have been encouraging, detailed s...

  16. Noninvasive measurement of an index of renal blood flow

    International Nuclear Information System (INIS)

    Powers, T.A.; Rees, R.S.; Bowen, R.D.

    1983-01-01

    A new technique for the noninvasive measurement of an index of renal blood flow is described. The method utilizes ultrasound determined renal volume and radionuclide assessment of the mean transit time of a pertechnetate bolus through the kidneys. From this information a value for flow is calculated according to compartmental analysis principles. There is good correlation between renal blood flow estimated by this technique and that determined by microsphere injection

  17. Rat muscle blood flows during high-speed locomotion

    International Nuclear Information System (INIS)

    Armstrong, R.B.; Laughlin, M.H.

    1985-01-01

    We previously studied blood flow distribution within and among rat muscles as a function of speed from walking (15 m/min) through galloping (75 m/min) on a motor-driven treadmill. The results showed that muscle blood flows continued to increase as a function of speed through 75 m/min. The purpose of the present study was to have rats run up to maximal treadmill speeds to determine if blood flows in the muscles reach a plateau as a function of running speed over the animals normal range of locomotory speeds. Muscle blood flows were measured with radiolabeled microspheres at 1 min of running at 75, 90, and 105 m/min in male Sprague-Dawley rats. The data indicate that even at these relatively high treadmill speeds there was still no clear evidence of a plateau in blood flow in most of the hindlimb muscles. Flows in most muscles continued to increase as a function of speed. These observed patterns of blood flow vs. running speed may have resulted from the rigorous selection of rats that were capable of performing the high-intensity exercise and thus only be representative of a highly specific population of animals. On the other hand, the data could be interpreted to indicate that the cardiovascular potential during exercise is considerably higher in laboratory rats than has normally been assumed and that inadequate blood flow delivery to the muscles does not serve as a major limitation to their locomotory performance

  18. Linear relationship between in distribution of thallium-201 and blood flow in ischemic and nonischemic myocardium during exercise

    International Nuclear Information System (INIS)

    Nielsen, A.P.; Morris, K.G.; Murdock, R.; Bruno, F.P.; Cobb, F.R.

    1980-01-01

    The purpose of this study was to compare the myocardial distribution of thallium-201 and regional myocrdial blood flow during ischemia and the physiologic stress of exercise. Studies were carried out in six dogs with chronically implanted catheters in the atrium and aorta and a snare on the circumflex coronary artery distal to the first marginal branch. Regional myocardial blood flow was measured during quiet, resting conditions using 7 to 10 ] of radioisotope-labeled microspheres. Each dog was then exercised on a treadmill at speeds of 5 to 9 mph at a 5/sup o/ incline. (After 1 minute of exercise the cirumflex coronary artery was occluded and thallium-201 and a second label of microspheres were injected. Exercise was continued for 5 minutes. The dogs were then sacrificed and the left ventricle was sectioned into approximately 80 1-2-g samples to compare thallium-201 activity and regional myocardial blood flow. The maximum increase in blood flow ranged from 3.3 to 7.2 times resting control values. Each dog had myocardial samples in which blood flow was markedly reduced, to less than 0.10 ml/min/g. In each dog there was a close linear relationship between thallium-201 distribution and direct measurements of regional myocardial blood flow. Linear regression analyses demonstrated a correlation coefficient of 0.98 or greater in each dog. These data indicate that during the physiologic stress of exercise, the myocardial distribution of thallium activity is linearly related to regional myocardial blood flow in both the ischemic and nonischemic regions

  19. Effects of Red Blood Cell Aggregation on the Apparent Viscosity of Blood Flow in Tubes.

    Science.gov (United States)

    Hitt, Darren L.; Lowe, Mary L.

    1996-11-01

    In arterioles and venules (20-200μ diameter), the low shear rates enable red blood cells to form aggregate structures of varying sizes and morphology. The size and distribution of the aggregates affect the flow impedance within a microvascular network; this effect may be characterized by an "apparent viscosity". In this study, we measure the apparent viscosity of blood flow in 50μ glass tubes as a function of shear rate and red blood cell volume fraction (hematocrit); for a fixed tube geometry and an imposed flow rate, the viscosity is determined by measuring the pressure drop across the tube. To correlate the apparent viscosity with the size and spatial distribution of the aggregates in the flow, video images of the flow are recorded and analyzed using power spectral techniques. Pig blood and sheep blood are used as the models for aggregating and non-aggregating blood, respectively. Supported by NSF PFF Award CTS-9253633

  20. Blood glucose control for patients with acute coronary syndromes in Qatar.

    Science.gov (United States)

    Wilby, Kyle John; Elmekaty, Eman; Abdallah, Ibtihal; Habra, Masa; Al-Siyabi, Khalid

    2016-01-01

    Blood glucose is known to be elevated in patients presenting with acute coronary syndromes. However a gap in knowledge exists regarding effective management strategies once admitted to acute care units. It is also unknown what factors (if any) predict elevated glucose values during initial presentation. OBJECTIVES of the study were to characterize blood glucose control in patients admitted to the cardiac care unit (CCU) in Qatar and to determine predictive factors associated with high glucose levels (>10 mmol/l) on admission to the CCU. All data for this study were obtained from the CCU at Heart Hospital in Doha, Qatar. A retrospective chart review was completed for patients admitted to the CCU in Qatar from October 1st, 2012 to March 31st, 2013, of which 283 were included. Baseline characteristics (age, gender, nationality, medical history, smoking status, type of acute coronary syndrome), capillary and lab blood glucose measurements, and use of insulin were extracted. Time spent in glucose ranges of 10 mmol/1 was calculated manually. Univariate and multivariate logistic regression were performed to assess factors associated with high glucose on admission. The primary analysis was completed with capillary data and a sensitivity analysis was completed using laboratory data. Blood glucose values measured on admission and throughout length of stay in the CCU. Capillary blood glucose data showed majority of time was spent in the range of >10 mmol/l (41.95%), followed by 4-8 mmol/l (35.44%), then 8-10 mmol/l (21.45%), and finally 10 mmol/l on admission (p < 0.05) in a univariate analysis but only diabetes remained significant in a multivariate model (OR 23.3; 95% CI, 11.5-47.3). Diabetes predicts high glucose values on hospital admission for patients with ACS and patients are not being adequately controlled throughout CCU stay.

  1. Conventional blood conservation techniques in 500 consecutive coronary artery bypass operations.

    Science.gov (United States)

    Ovrum, E; Holen, E A; Abdelnoor, M; Oystese, R

    1991-09-01

    With use of a nonpharmacological, simple, and inexpensive program for blood conservation, 500 consecutive patients underwent elective coronary artery bypass grafting without need of homologous red cell transfusions in 493 (98.6%). At least one internal mammary artery was grafted in all but 1 patient, with supplemental saphenous vein grafts. Intraoperatively, autologous heparinized blood was removed before bypass and retransfused at the conclusion of extracorporeal circulation. The volume remaining in the oxygenator and tubing set was returned without cell processing or hemofiltration. Using the hard-shell cardiotomy reservoir from the heart-lung machine, autotransfusion of the shed mediastinal blood was continued hourly up to 18 hours after operation. The mean postoperative mediastinal blood loss was 643 +/- 354 mL, whereas 624 +/- 296 mL was autotransfused. Thirteen patients (2.6%) needed reexploration for bleeding, of whom 7 (7/500, 1.4%) received homologous blood. No other patients required red cell transfusions. In addition, 9 patients were given a mean of 2.6 units of fresh frozen plasma because of suspected coagulopathy. No platelets were transfused, and no cryoprecipitate therapy was undertaken. Thus, in total, 484 patients (96.8%) were not exposed to any homologous blood products during the hospital stay. At discharge, the mean hemoglobin concentration was 121 +/- 14 g/L (12.1 +/- 1.4 g/dL) and the hematocrit, 0.36 +/- 0.04. Postoperative complications were few. There was one in-hospital death (0.2%).

  2. [Clinical research of minimal extracorporeal circulation in perioperative blood conservation of coronary artery bypass graft].

    Science.gov (United States)

    Liu, Yan; Cui, Hu-jun; Tao, Liang; Chen, Xu-fa

    2011-04-01

    To analyze the clinical effect of minimal extracorporeal circulation (MECC) in blood conservation perioperatively coronary artery bypass graft (CABG). The data of 120 cases received simple CABG since August 2006 to October 2009 was analyzed retrospectively. All the patients were divided to three groups according to the mode of circulation support in-operation: MECC, conventional extracorporeal circulation (cECC) or off-pump, 40 cases in each group. Jostra MECC system with normal temperature was used in MECC group, and common membrane oxygenator with moderate hypo-temperature was used in cECC group. Collect the data of coagulation and the blood cytological examination perioperatively, the draining volume during the first 24 h after operation, and consumption of blood products perioperatively. Standard and logistic EuroSCORE were higher in MECC group than the others (P blood products in cECC group, but no difference among the three groups. MECC could reduce the ruin to blood cell and interfere to coagulation function during the conventional ECC procedure, decrease the postoperative draining volume and requirement of blood products.

  3. Spiral blood flow in aorta-renal bifurcation models.

    Science.gov (United States)

    Javadzadegan, Ashkan; Simmons, Anne; Barber, Tracie

    2016-01-01

    The presence of a spiral arterial blood flow pattern in humans has been widely accepted. It is believed that this spiral component of the blood flow alters arterial haemodynamics in both positive and negative ways. The purpose of this study was to determine the effect of spiral flow on haemodynamic changes in aorta-renal bifurcations. In this regard, a computational fluid dynamics analysis of pulsatile blood flow was performed in two idealised models of aorta-renal bifurcations with and without flow diverter. The results show that the spirality effect causes a substantial variation in blood velocity distribution, while causing only slight changes in fluid shear stress patterns. The dominant observed effect of spiral flow is on turbulent kinetic energy and flow recirculation zones. As spiral flow intensity increases, the rate of turbulent kinetic energy production decreases, reducing the region of potential damage to red blood cells and endothelial cells. Furthermore, the recirculation zones which form on the cranial sides of the aorta and renal artery shrink in size in the presence of spirality effect; this may lower the rate of atherosclerosis development and progression in the aorta-renal bifurcation. These results indicate that the spiral nature of blood flow has atheroprotective effects in renal arteries and should be taken into consideration in analyses of the aorta and renal arteries.

  4. Regional cerebral blood flow measurement in brain tumors

    International Nuclear Information System (INIS)

    Izunaga, Hiroshi; Hirota, Yoshihisa; Takahashi, Mutsumasa; Fuwa, Isao; Kodama, Takafumi; Matsukado, Yasuhiko

    1986-01-01

    The regional cerebral blood flow (CBF) was determined on seventeen patients with brain tumors. Ring type single photon emission CT (SPECT) was used following intravenous injection of 133 Xe. Case materials included eleven meningiomas and six malignant gliomas. Evaluation was performed with emphasis on the following points; 1. Correlation of the flow data within tumors to the angiographic tumor stains, 2. Influence of tumors on the cerebral blood flow of the normal brain tissue, 3. Correlation between degree of peripheral edema and the flow data of the affected hemispheres. There was significant correlation between flow data within tumors and angiographic tumor stains in meningiomas. Influence of tumors on cerebral blood flow of the normal tissue was greater in meningiomas than in gliomas. There was negative correlation between the degree of peripheral edema and the flow data of the affected hemisphere. It has been concluded that the measurement of CBF in brain tumors is a valuable method in evaluation of brain tumors. (author)

  5. Regional cerebral blood flow measurement in brain tumors

    Energy Technology Data Exchange (ETDEWEB)

    Izunaga, Hiroshi; Hirota, Yoshihisa; Takahashi, Mutsumasa; Fuwa, Isao; Kodama, Takafumi; Matsukado, Yasuhiko

    1986-10-01

    The regional cerebral blood flow (CBF) was determined on seventeen patients with brain tumors. Ring type single photon emission CT (SPECT) was used following intravenous injection of /sup 133/Xe. Case materials included eleven meningiomas and six malignant gliomas. Evaluation was performed with emphasis on the following points; 1. Correlation of the flow data within tumors to the angiographic tumor stains, 2. Influence of tumors on the cerebral blood flow of the normal brain tissue, 3. Correlation between degree of peripheral edema and the flow data of the affected hemispheres. There was significant correlation between flow data within tumors and angiographic tumor stains in meningiomas. Influence of tumors on cerebral blood flow of the normal tissue was greater in meningiomas than in gliomas. There was negative correlation between the degree of peripheral edema and the flow data of the affected hemisphere. It has been concluded that the measurement of CBF in brain tumors is a valuable method in evaluation of brain tumors.

  6. On the flow dependency of the electrical conductivity of blood

    NARCIS (Netherlands)

    Hoetink, AE; Faes, TJC; Visser, KR; Heethaar, RM

    Experiments presented in the literature show that the electrical conductivity of flowing blood depends on flow velocity. The aim of this study is to extend the Maxwell-Fricke theory, developed for a dilute suspension of ellipsoidal particles in an electrolyte, to explain this flow dependency of the

  7. Laser Doppler flowmetry for measurement of laminar capillary blood flow in the horse

    Science.gov (United States)

    Adair, Henry S., III

    1998-07-01

    Current methods for in vivo evaluation of digital hemodynamics in the horse include angiography, scintigraphy, Doppler ultrasound, electromagnetic flow and isolated extracorporeal pump perfused digit preparations. These techniques are either non-quantifiable, do not allow for continuous measurement, require destruction of the horse orare invasive, inducing non- physiologic variables. In vitro techniques have also been reported for the evaluation of the effects of vasoactive agents on the digital vessels. The in vitro techniques are non-physiologic and have evaluated the vasculature proximal to the coronary band. Lastly, many of these techniques require general anesthesia or euthanasia of the animal. Laser Doppler flowmetry is a non-invasive, continuous measure of capillary blood flow. Laser Doppler flowmetry has been used to measure capillary blood flow in many tissues. The principle of this method is to measure the Doppler shift, that is, the frequency change that light undergoes when reflected by moving objects, such as red blood cells. Laser Doppler flowmetry records a continuous measurement of the red cell motion in the outer layer of the tissue under study, with little or no influence on physiologic blood flow. This output value constitutes the flux of red cells and is reported as capillary perfusion units. No direct information concerning oxygen, nutrient or waste metabolite exchange in the surrounding tissue is obtained. The relationship between the flowmeter output signal and the flux of red blood cells is linear. The principles of laser Doppler flowmetry will be discussed and the technique for laminar capillary blood flow measurements will be presented.

  8. Flow and wall shear stress in end-to-side and side-to-side anastomosis of venous coronary artery bypass grafts

    Directory of Open Access Journals (Sweden)

    Poulikakos Dimos

    2007-09-01

    Full Text Available Abstract Purpose Coronary artery bypass graft (CABG surgery represents the standard treatment of advanced coronary artery disease. Two major types of anastomosis exist to connect the graft to the coronary artery, i.e., by using an end-to-side or a side-to-side anastomosis. There is still controversy because of the differences in the patency rates of the two types of anastomosis. The purpose of this paper is to non-invasively quantify hemodynamic parameters, such as mass flow and wall shear stress (WSS, in end-to-side and side-to-side anastomoses of patients with CABG using computational fluid dynamics (CFD. Methods One patient with saphenous CABG and end-to-side anastomosis and one patient with saphenous CABG and side-to-side anastomosis underwent 16-detector row computed tomography (CT. Geometric models of coronary arteries and bypasses were reconstructed for CFD analysis. Blood flow was considered pulsatile, laminar, incompressible and Newtonian. Peri-anastomotic mass flow and WSS were quantified and flow patterns visualized. Results CFD analysis based on in-vivo CT coronary angiography data was feasible in both patients. For both types of CABG, flow patterns were characterized by a retrograde flow into the native coronary artery. WSS variations were found in both anastomoses types, with highest WSS values at the heel and lowest WSS values at the floor of the end-to-side anastomosis. In contrast, the highest WSS values of the side-to-side anastomosis configuration were found in stenotic vessel segments and not in the close vicinity of the anastomosis. Flow stagnation zones were found in end-to-side but not in side-to-side anastomosis, the latter also demonstrating a smoother stream division throughout the cardiac cycle. Conclusion CFD analysis of venous CABG based on in-vivo CT datasets in patients was feasible producing qualitative and quantitative information on mass flow and WSS. Differences were found between the two types of anastomosis

  9. New noninvasive diagnosis of myocardial ischemia of the left circumflex coronary artery using coronary flow reserve measurement by transthoracic Doppler echocardiography. Comparison with thallium-201 single photon emission computed tomography

    International Nuclear Information System (INIS)

    Fujimoto, Kohei; Watanabe, Hiroyuki; Hozumi, Takeshi; Otsuka, Ryo; Hirata, Kumiko; Yamagishi, Hiroyuki; Yoshiyama, Minoru; Yoshikawa, Junichi

    2004-01-01

    The usefulness of coronary flow reserve measurement in the left circumflex coronary artery by transthoracic Doppler echocardiography to detect myocardial ischemia was compared with exercise thallium-201 single photon emission computed tomography (SPECT). Transthoracic Doppler echocardiography was performed in 110 patients with suspected coronary artery disease. Color Doppler signals of the left circumflex coronary artery flow in the apical four-chamber view were identified, and the velocities at rest and during hyperemia recorded for calculation of coronary flow reserve by the pulsed Doppler method. All patients underwent SPECT within 1 week of the transthoracic Doppler echocardiographic study. Coronary flow reserve in the left circumflex coronary artery was measured in 79 (72%) of 110 patients. SPECT revealed reversible perfusion defect in the left circumflex coronary artery territories in 12 of 69 patients excluding those with multivessel disease. Coronary flow reserve <2.0 had a sensitivity of 92% and specificity of 96% for reversible perfusion defect detected by SPECT. Noninvasive coronary flow reserve measurement in the left circumflex coronary artery by transthoracic Doppler echocardiography can estimate myocardial ischemia in the left ventricular lateral regions. (author)

  10. Regulation of Blood Flow in Contracting Skeletal Muscle in Aging

    DEFF Research Database (Denmark)

    Piil, Peter Bergmann

    Oxygen delivery to skeletal muscle is regulated precisely to match the oxygen demand; however, with aging the regulation of oxygen delivery during exercise is impaired. The present thesis investigated mechanisms underlying the age-related impairment in regulation of blood flow and oxygen delivery......GMP) was used as intervention, and skeletal muscle blood flow, oxygen delivery, and functional sympatholysis was examined. The two studies included 53 healthy, habitually active, male subjects. All subjects participated in an experimental day in which femoral arterial blood flow and blood pressure were assessed...... that improving sympatholytic capacity by training may be a slower process in older than in young men. In conclusion, this thesis provides new important knowledge related to the regulation of skeletal muscle blood flow in aging. Specifically, it demonstrates that changes in cGMP signaling is an underlying cause...

  11. Evaluation of nonradioactive, colored microspheres for measurement of regional myocardial blood flow in dogs

    International Nuclear Information System (INIS)

    Hale, S.L.; Alker, K.J.; Kloner, R.A.

    1988-01-01

    Measurement of regional myocardial blood flow (RMBF) is crucial in experimental studies of myocardial ischemia and reperfusion in dogs. The standard measurement technique uses radioactive microspheres; however, not all institutions are able to dispose of radioactive waste and therefore cannot make use of this method. We tested a new, nonradioactive microsphere, labeled with colors instead of nuclides. Simultaneous blood flow measurements with two nuclide-labeled and two colored microspheres were performed after coronary occlusion in dogs. Both techniques show a within-method correlation of r greater than 0.98. Duplicate variability for paired RMBF values in 80 samples was 8.7 +/- 0.1% when computed with radioactive microspheres and 13.2 +/- 1.8% when computed with colored microspheres. There was a good correlation in the measurement of RMBF between the radioactive- and colored-microsphere methods (r = 0.98). The best-fitting linear regression line was expressed by the formula: Colored-microsphere RMBF = 1.11 (radioactive-microsphere RMBF)-0.02. When measured by colored microspheres, RMBF was approximately 8% higher than when computed with radioactive microspheres for blood flow values of 0-2 ml/min/g. When blood flow was increased pharmacologically to levels of 2-7.5 ml/min/g, colored microspheres yielded blood flow values 39% higher than the values computed by radioactive microspheres. We conclude that the nonradioactive, colored-microsphere method correlates with the radioactive technique, but at high flows, it yields values greater than those obtained with radioactive microspheres

  12. Nasal mucosal blood flow after intranasal allergen challenge

    International Nuclear Information System (INIS)

    Holmberg, K.; Bake, B.; Pipkorn, U.

    1988-01-01

    The nasal mucosal blood flow in patients with allergic rhinitis was determined at nasal allergen challenges with the 133 Xenon washout method. Determinations were made in 12 subjects before and 15 minutes after challenge with diluent and increasing doses of allergen. The time course was followed in eight subjects by means of repeated measurements during 1 hour after a single allergen dose. Finally, the blood flow was measured after unilateral allergen challenge in the contralateral nasal cavity. A dose-dependent decrease in blood flow was found after nasal challenge with increasing doses of allergens, whereas challenge with diluent alone did not induce any changes. The highest allergen dose, which also induced pronounced nasal symptoms, resulted in a decrease in blood flow of 25% (p less than 0.001). The time-course study demonstrated a maximum decrease in blood flow 10 to 20 minutes after challenge and then a gradual return to baseline. Unilateral allergen challenge resulted in a decrease in blood flow in the contralateral, unchallenged nasal cavity, suggesting that part of the allergen-induced changes in blood flow were reflex mediated

  13. The role of blood flow in chronic duodenal ulcer

    Energy Technology Data Exchange (ETDEWEB)

    Gompertz, R.H.K.; Mathie, R.T.; Michalowski, A.S.; Spencer, J.; Baron, J.H.; Williamson, R.C.N.

    1996-01-01

    Changes in gastroduodenal blood flow have been implicated in the pathogenesis of duodenal ulcer. The authors have studied duodenal blood flow during the development of an acute to chronic duodenal ulcer by using the abscopal model, in which ulcers are generated as an indirect effect of lower mediastinal irradiation. Female CFLP mice were randomly allocated to one of three groups. Irradiated ``controls`` received 18 Gy 250 kV X-rays to the upper mediastinum. The lower mediastinum group received the same dose of irradiation, which has been shown to induce typical chronic duodenal ulcers in 45% of animals so treated. Animals were studied by means of radiolabelled microspheres 3 or 7 days later. Proximal duodenal blood flow specifically was reduced by 32% in the lower mediastinum group compared with irradiated controls at 7 days. There was no significant difference in blood flow to the stomach and to the distal duodenum. The decrease in proximal duodenal blood flow in the lower mediastinum group did not differ in the five animals that developed ulcer compared with the seven that did not. Although, there is an overall decrease in duodenal blood flow associated with chronic duodenal ulcer, reduced blood flow may not explain individual susceptibility to ulceration. 21 refs., 1 fig., 2 tabs.

  14. 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

  15. Increased bone marrow blood flow in polycythemia vera

    International Nuclear Information System (INIS)

    Lathinen, R.; Lathinen, T.; Hyoedynmaa, S.

    1983-01-01

    Bone marrow blood flow was measured in polycythemia vera, in compensatory and in relative polycythemia with a 133 Xe washout method. In the treated polycythemia vera bone marrow blood flow was significantly increased compared with the age-matched controls. The fraction of blood flow entering the bone and flowing through the hematopoietic marrow was markedly increased in both the untreated and the treated polycythemia vera. Although the number of observations in compensatory and relative polycythemia was small, the results suggest that bone marrow blood flow is not markedly increased in these diseases. The results also suggest that in older patients the simple 133 Xe method may support the diagnosis of polycythemia vera. (orig.)

  16. Increased bone marrow blood flow in polycythemia vera

    Energy Technology Data Exchange (ETDEWEB)

    Lathinen, R.; Lathinen, T.; Hyoedynmaa, S.

    1983-01-01

    Bone marrow blood flow was measured in polycythemia vera, in compensatory and in relative polycythemia with a /sup 133/Xe washout method. In the treated polycythemia vera bone marrow blood flow was significantly increased compared with the age-matched controls. The fraction of blood flow entering the bone and flowing through the hematopoietic marrow was markedly increased in both the untreated and the treated polycythemia vera. Although the number of observations in compensatory and relative polycythemia was small, the results suggest that bone marrow blood flow is not markedly increased in these diseases. The results also suggest that in older patients the simple /sup 133/Xe method may support the diagnosis of polycythemia vera.

  17. Associations between COX-2 polymorphisms, blood cholesterol and risk of acute coronary syndrome

    DEFF Research Database (Denmark)

    Vogel, Ulla Birgitte; Segel, Stine; Dethlefsen, Claus

    2010-01-01

    the enzyme levels of COX-2, were associated with risk of ACS and if alcohol intake, smoking, and use of NSAID would modify the associations. We also wanted to investigate associations with blood lipid levels. Methods: A case–cohort study including 1031 ACS cases and a sub-cohort of 1703 persons was nested......), such that variant allele carriers with low alcohol intake had the lowest lipid levels. No statistically significant associations were observed in females. Conclusion: This study suggests that genetically determined COX-2 levels are associated with risk of ACS and blood lipid levels among males. No consistent......Background: The use of specific COX-2 inhibitors in cancer prevention has been associated with higher risk of acute coronary syndrome (ACS) and myocardial infarction. The aim of this study was to investigate if the polymorphisms COX2 T8473C (rs5275), and COX2 A-1195G (rs689466), which modify...

  18. Experimental studies of renal blood flow by digitized functional angiography

    International Nuclear Information System (INIS)

    Buersch, J.H.; Ochs, C.; Hahne, H.J.; Heintzen, P.H.

    1985-01-01

    New techniques of digital image processing have been experimentally tested for the assessment of renal blood flow. The underlying principle in functional angiography is the extraction of flow parameters. Basically, density-time variations of the contrast medium are analayzed from to each picture element of a 256x256 matrix. The real-time acquisition rate of images was 25/sec. For the calculation of angiographic flow a PDP 11/40 computer was used to interactively perform a time dependent segmentation of the renal arteries and the aorta. Subsequently, volume flow was calculated in relative units for the specific vascular segments under study. 15 control angiograms were made in 5 animals with cardiac output ranging between 0.8 to 2.2l/min. Unilateral renal blood flow was calculated as 24+-3.4% of pre-renal aortic flow without systematic side differences. Reproducibility from repeated flow measurements showed an SD of +-1.8% of the individual pre-renal aortic flow. Renal flow was also measured in 3 animals with an experimentally created 50% flow reduction of the left kidney. Angiographic flow in the left renal artery dropped to 12+-2% of pre-renal flow. The present experimental data suggest that digital angiography has sufficient diagnostic capabilities for the detection of abnormal renal blood flow. The technique may serve as a useful diagnostic adjunct to conventional angiography and has the potential of assisting in the evaluation of renal vascular hypertension. (orig.) [de

  19. Structural alterations of the coronary arterial wall are associated with myocardial flow heterogeneity in type 2 diabetes mellitus

    International Nuclear Information System (INIS)

    Schindler, Thomas H.; Facta, Alvaro D.; Prior, John O.; Cadenas, Jerson; Zhang, Xiao-Li; Sayre, James; Goldin, Jonathan; Schelbert, Heinrich R.

    2009-01-01

    To determine the relationship between carotid intima-media thickness (IMT), coronary artery calcification (CAC), and myocardial blood flow (MBF) at rest and during vasomotor stress in type 2 diabetes mellitus (DM). In 68 individuals, carotid IMT was measured using high-resolution vascular ultrasound, while the presence of CAC was determined with electron beam tomography (EBT). Global and regional MBF was determined in milliliters per gram per minute with 13 N-ammonia and positron emission tomography (PET) at rest, during cold pressor testing (CPT), and during adenosine (ADO) stimulation. There was neither a relationship between carotid IMT and CAC (r = 0.10, p = 0.32) nor between carotid IMT and coronary circulatory function in response to CPT and during ADO (r = -0.18, p = 0.25 and r = 0.10, p = 0.54, respectively). In 33 individuals, EBT detected CAC with a mean Agatston-derived calcium score of 44 ± 18. There was a significant difference in regional MBFs between territories with and without CAC at rest and during ADO-stimulated hyperemia (0.69 ± 0.24 vs. 0.74 ± 0.23 and 1.82 ± 0.50 vs. 1.95 ± 0.51 ml/g/min; p ≤ 0.05, respectively) and also during CPT in DM but less pronounced (0.81 ± 0.24 vs. 0.83 ± 0.23 ml/g/min; p = ns). The increase in CAC was paralleled with a progressive regional decrease in resting as well as in CPT- and ADO-related MBFs (r = -0.36, p ≤ 0.014; r = -0.46, p ≤ 0.007; and r = -0.33, p ≤ 0.041, respectively). The absence of any correlation between carotid IMT and coronary circulatory function in type 2 DM suggests different features and stages of early atherosclerosis in the peripheral and coronary circulation. PET-measured MBF heterogeneity at rest and during vasomotor stress may reflect downstream fluid dynamic effects of coronary artery disease (CAD)-related early structural alterations of the arterial wall. (orig.)

  20. Relationship between blood viscosity and infarct size in patients with ST-segment elevation myocardial infarction undergoing primary percutaneous coronary intervention.

    Science.gov (United States)

    Cecchi, Emanuele; Liotta, Agatina Alessandriello; Gori, Anna Maria; Valente, Serafina; Giglioli, Cristina; Lazzeri, Chiara; Sofi, Francesco; Gensini, Gian Franco; Abbate, Rosanna; Mannini, Lucia

    2009-05-15

    Previous studies explored the association between hemorheological alterations and acute myocardial infarction, pointing out the role of hematological components on microvascular flow. The aim of this study was to evaluate the association between blood viscosity and infarct size, estimated by creatine kinase (CK) peak activity and cardiac Troponin I (cTnI) peak concentration in ST-segment elevation myocardial infarction (STEMI) patients after primary percutaneous coronary intervention (PCI). The study population included 197 patients with diagnosis of STEMI undergoing PCI. Hemorheological studies were performed by assessing whole blood viscosity (measured at shear rates of 0.512 s(-1) and 94.5 s(-1)) and plasma viscosity using the Rotational Viscosimeter LS 30 and erythrocyte deformability index by Myrenne filtrometer. Significant correlations between CK peak activity, cTnI peak concentration, left ventricular ejection fraction and hemorheological variables were observed. At linear regression analysis (adjusted for age, gender, traditional cardiovascular risk factors, renal dysfunction, timeliness of reperfusion, pre-PCI TIMI flow, infarct location, multivessel disease and previous coronary artery disease) leukocytes and whole blood viscosity at 0.512 s(-1) and 94.5 s(-1) were independently and positively associated with infarct size. These results demonstrate a significant and independent association between hemorheology and infarct size in STEMI patients after PCI suggesting that blood viscosity, in a condition of low flow, might worsen myocardial perfusion leading to an increased infarct size. The measurement of whole blood viscosity in STEMI patients could help to identify those who may benefit from new therapeutic strategies.

  1. Collateral sources of costal and crural diaphragmatic blood flow

    International Nuclear Information System (INIS)

    Lockhat, D.; Magder, S.; Roussos, C.

    1985-01-01

    We measured the contribution of aortic, internal mammary, and intercostal arteries to the blood flow to the costal and crural segments of the diaphragm and other respiratory muscles in seven dogs breathing against a fixed inspiratory elastic load. We used radiolabeled microspheres to measure the blood flow with control circulation, occlusion of the aorta distal to the left subclavian artery, combined occlusion of the aorta and both internal mammary arteries, and occlusion of internal mammary arteries alone. With occlusion of the aorta distal to the left subclavian artery, blood flow to the crural diaphragm decreased from 40.3 to 23.5 ml . min-1 X 100 g-1, whereas costal flow did not change significantly (from 41.7 to 38.1 ml . min-1 . 100 g-1). Blood flows to the sternomastoid and scalene muscles (above the occlusion) increased by 200 and 340%, respectively, whereas flows to the other respiratory muscles did not change significantly. Blood flows to organs above the occlusion either remained unchanged or increased, whereas flows to those below the occlusion all decreased. When the internal mammary artery was also occluded, flows to the crural segment decreased further to 12.1 and costal flow decreased to 20.4 ml X min-1 X 100 g-1. Internal mammary arterial occlusion alone in two dogs had no effect on diaphragmatic flow. In conclusion, intercostal collateral vessels are capable of supplying a significant proportion of blood flow to both segments of the diaphragm but the costal segment is better served than the crural segment

  2. Direct effects of smoking on the heart: silent ischemic disturbances of coronary flow

    International Nuclear Information System (INIS)

    Deanfield, J.E.; Shea, M.J.; Wilson, R.A.; Horlock, P.; de Landsheere, C.M.; Selwyn, A.P.

    1986-01-01

    Cigarette smoking is strongly associated with ischemic heart disease and acute coronary events. The effect of smoking a single cigarette on regional myocardial perfusion was studied in 13 chronic smokers with typical stable angina pectoris using positron emission tomography and rubidium-82 ( 82 Rb). Findings were compared with the effects of physical exercise. After exercise, 8 patients (61%) had angina, ST depression and abnormal regional myocardial perfusion. Uptake of 82 Rb increased from 49 +/- 8 to 60 +/- 7 in remote myocardium, but decreased from 46 +/- 3 to 37 +/- 5 in an ischemic area. The remaining 5 patients (39%) had homogeneous increases in 82 Rb uptake without angina or ST depression. After smoking, 6 of the 8 patients with positive exercise test responses had a decrease in 82 Rb uptake, from 47 +/- 3 to 35 +/- 6 in the same segment of myocardium affected during exercise. However, in contrast to exercise, the events during smoking were largely silent. The absolute decreases in regional 82 Rb uptake after smoking occurred at significantly lower levels of myocardial oxygen demand than after exercise. This suggests that an impairment of coronary blood supply is responsible. Thus, in smokers with coronary artery disease, each cigarette can cause profound silent disturbances of regional myocardial perfusion that are likely to occur frequently during daily life. Such repeated insults may represent an important mechanism linking smoking with coronary events

  3. Muscle blood flow at onset of dynamic exercise in humans.

    Science.gov (United States)

    Rådegran, G; Saltin, B

    1998-01-01

    To evaluate the temporal relationship between blood flow, blood pressure, and muscle contractions, we continuously measured femoral arterial inflow with ultrasound Doppler at onset of passive exercise and voluntary, one-legged, dynamic knee-extensor exercise in humans. Blood velocity and inflow increased (P dicrotic and diastolic blood pressure notches, respectively. Mechanical hindrance occurred (P dicrotic notch. The increase in blood flow (Q) was characterized by a one-component (approximately 15% of peak power output), two-component (approximately 40-70% of peak power output), or three-component exponential model (> or = 75% of peak power output), where Q(t) = Qpassive + delta Q1.[1 - e-(t - TD1/tau 1)]+ delta Q2.[1 - e-(t - TD2/tau 2)]+ delta Q3.[1 - e-(t - TD3/tau 3)]; Qpassive, the blood flow during passive leg movement, equals 1.17 +/- 0.11 l/min; TD is the onset latency; tau is the time constant; delta Q is the magnitude of blood flow rise; and subscripts 1-3 refer to the first, second, and third components of the exponential model, respectively. The time to reach 50% of the difference between passive and voluntary asymptotic blood flow was approximately 2.2-8.9 s. The blood flow leveled off after approximately 10-150 s, related to the power outputs. It is concluded that the elevation in blood flow with the first duty cycle(s) is due to muscle mechanical factors, but vasodilators initiate a more potent amplification within the second to fourth contraction.

  4. Local viscosity distribution in bifurcating microfluidic blood flows

    Science.gov (United States)

    Kaliviotis, E.; Sherwood, J. M.; Balabani, S.

    2018-03-01

    The red blood cell (RBC) aggregation phenomenon is majorly responsible for the non-Newtonian nature of blood, influencing the blood flow characteristics in the microvasculature. Of considerable interest is the behaviour of the fluid at the bifurcating regions. In vitro experiments, using microchannels, have shown that RBC aggregation, at certain flow conditions, affects the bluntness and skewness of the velocity profile, the local RBC concentration, and the cell-depleted layer at the channel walls. In addition, the developed RBC aggregates appear unevenly distributed in the outlets of these channels depending on their spatial distribution in the feeding branch, and on the flow conditions in the outlet branches. In the present work, constitutive equations of blood viscosity, from earlier work of the authors, are applied to flows in a T-type bifurcating microchannel to examine the local viscosity characteristics. Viscosity maps are derived for various flow distributions in the outlet branches of the channel, and the location of maximum viscosity magnitude is obtained. The viscosity does not appear significantly elevated in the branches of lower flow rate as would be expected on the basis of the low shear therein, and the maximum magnitude appears in the vicinity of the junction, and towards the side of the outlet branch with the higher flow rate. The study demonstrates that in the branches of lower flow rate, the local viscosity is also low, helping us to explain why the effects of physiological red blood cell aggregation have no adverse effects in terms of in vivo vascular resistance.

  5. Arterial secondary blood flow patterns visualized with vector flow ultrasound

    DEFF Research Database (Denmark)

    Pedersen, Mads Møller; Pihl, Michael Johannes; Hansen, Jens Munk

    2011-01-01

    This study presents the first quantification and visualisation of secondary flow patterns with vector flow ultrasound. The first commercial implementation of the vector flow method Transverse Oscillation was used to obtain in-vivo, 2D vector fields in real-time. The hypothesis of this study...... was that the rotational direction is constant within each artery. Three data sets of 10 seconds were obtained from three main arteries in healthy volunteers. For each data set the rotational flow patterns were identified during the diastole. Each data set contains a 2D vector field over time and with the vector angles...

  6. Low cerebral blood flow in hypotensive perinatal distress

    International Nuclear Information System (INIS)

    Lou, H.C.; Lassen, N.A.; Friis-Hansen, B.

    1977-01-01

    Hypoxic brain injury is the most important neurological problem in the neonatal period and accounts for more neurological deficits in children than any other lesion. The neurological deficits are notably mental retardation, epilepsy and cerebral palsy. The pathogenesis has hitherto been poorly understood. Arterial hypoxia has been taken as the obvious mechanism but this does not fully explain the patho-anatomical findings. In the present investigation we have examined the arterial blood pressure and the cerebral blood flow in eight infants a few hours after birth. The 133Xe clearance technique was used for the cerebral blood flow measurements. The study confirmed that perinatal distress may be associated with low arterial blood pressure, and it was shown that cerebral blood flow is very low, 20 ml/100 g/min or less, in hypotensive perinatal distress. It is concluded that cerebral ischaemia plays a crucial role in the development of perinatal hypoxic brain injury. (author)

  7. Aging, regional cerebral blood flow, and neuropsychological functioning

    International Nuclear Information System (INIS)

    MacInnes, W.D.; Golden, C.J.; Gillen, R.W.; Sawicki, R.F.; Quaife, M.; Uhl, H.S.; Greenhouse, A.J.

    1984-01-01

    Previous studies found changes in regional cerebral blood flow (rCBF) patterns related to both age and various cognitive tasks. However, no study has yet demonstrated a relationship between rCBF and performance on the Luria-Nebraska Neuropsychological Battery (LNNB) in an elderly group. Seventy-nine elderly volunteers (56-88 years old), both healthy and demented, underwent the 133 xenon inhalation rCBF procedure and were given the LNNB. The decrements in the gray-matter blood flow paralleled decrements in performance on the LNNB. Using partial correlations, a significant proportion of shared variance was observed between gray-matter blood flow and the LNNB scales. However, there was much less of a relationship between white-matter blood flow and performance on the LNNB. This study suggests that even within a restricted age sample rCBF is related in a global way to neuropsychological functioning

  8. Dynamic emission tomography of regional cerebral blood flow

    International Nuclear Information System (INIS)

    Lassen, N.A.

    1984-01-01

    The author reviews three tomographic methods for measuring the regional cerebral blood flow: single photon transmission tomography; dual photon emission tomography; and single photon emission tomography. The latter technique is discussed in detail. (Auth.)

  9. Qualitative Resting Coronary Pressure Wave Form Analysis to Predict Fractional Flow Reserve.

    Science.gov (United States)

    Matsumura, Mitsuaki; Maehara, Akiko; Johnson, Nils P; Fearon, William F; De Bruyne, Bernard; Oldroyd, Keith G; Pijls, Nico H J; Jenkins, Paul; Ali, Ziad A; Mintz, Gary S; Stone, Gregg W; Jeremias, Allen

    2018-03-27

    To evaluate the predictability of resting distal coronary pressure wave forms for fractional flow reserve (FFR). Resting coronary wave forms were qualitatively evaluated for the presence of (i) dicrotic notch; (ii) diastolic dipping; and (iii) ventricularization. In a development cohort (n=88) a scoring system was developed that was then applied to a validation cohort (n=428) using a multivariable linear regression model to predict FFR and receiver operating characteristics (ROC) to predict FFR ≤0.8. In the development cohort, all 3 qualitative parameters were independent predictors of FFR. However, in a multivariable linear regression model in the validation cohort, qualitative wave form analysis did not further improve the ability of resting distal coronary to aortic pressure ratio (Pd/Pa) (p=0.80) or instantaneous wave-free ratio (iFR) (p=0.26) to predict FFR. Using ROC, the area under the curve of resting Pd/Pa (0.86 versus 0.86, P=0.08) and iFR (0.86 versus 0.86, P=0.26) did not improve by adding qualitative analysis. Qualitative coronary wave form analysis showed moderate classification agreement in predicting FFR but did not add substantially to the resting pressure gradients Pd/Pa and iFR; however, when discrepancies between quantitative and qualitative analyses are observed, artifact or pressure drift should be considered.

  10. The effects of intraoperative autologous whole blood sequestration on the need for transfusion of allogenic blood and blood products in coronary bypass operations.

    Science.gov (United States)

    Canver, C C; Kroncke, G M; Nichols, R D; Murray, E L; Mentzer, R M

    1995-10-01

    We investigated the effect of intraoperative autologous blood sequestration (IABS), an old blood conservation method, on transfusion requirements for homologous packed red blood cells (PRBC), platelets, and fresh frozen plasma (FFP) for patients undergoing coronary bypass surgery. This non-randomized retrospective study involved 204 patients who underwent isolated primary coronary artery bypass grafting (CABG). In 140 patients (IABS Group), autologous heparinized whole blood was removed intraoperatively via aortic cannula before bypass and retransfused at the conclusion of extracorporeal circulation. In 64 control patients, no IABS was performed. Demographic characteristics and operative and perioperative variables for both groups were similar (p > 0.05). In 140 patients, the mean sequestered blood volume was 1430 ml (range = 700-2100 ml). The banked PRBC requirement during hospitalization was 1.91 units in the No IABS Group and 2.25 units for the IABS Group (p = 0.2957). The need for platelet transfusion was 3.06 units in the No IABS Group and 1.09 units in the IABS Group (p = 0.0003). In the No IABS Group, 1.31 units of FFP was transfused and in the IABS Group, 0.49 units was transfused (p = 0.0004). To identify possible confounding factors, we performed a multivariate Poisson regression analysis for the 22 patient variables by a forward stepwise procedure. Regression analysis indicated that IABS did not alter the need for PRBC transfusion (p = 0.6194) but adjusted differences did confirm that IABS was associated with decreased need for transfusion of platelets and FFP (p = 0.0001 and p = 0.0002, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

  11. EPA and DHA in blood cell membranes from acute coronary syndrome patients and controls.

    Science.gov (United States)

    Block, Robert C; Harris, William S; Reid, Kimberly J; Sands, Scott A; Spertus, John A

    2008-04-01

    Increased blood levels of the omega-3 fatty acids (FA) eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) have been inversely associated with risk for sudden cardiac death, but their relationship with acute coronary syndromes (ACS) is unclear. We hypothesized that the EPA+DHA content of blood cell membranes, as a percent of total FAs, is reduced in ACS patients relative to matched controls. We measured the content of EPA+DHA in 768 ACS patients and 768 age-, sex- and race-matched controls. The association with ACS case status of blood cell EPA+DHA [both by a 1 unit change and by category (low, or =8%)] was assessed using multivariate conditional logistic regression models adjusting for matching variables and smoking status, alcohol use, diabetes, body mass index, serum lipids, education, family history of coronary artery disease, personal histories of myocardial infarction and hypertension, and statin, aspirin, and other antiplatelet drug use. The combined groups had a mean age of 61+/-12 years, 66% were male, and 92% were Caucasian. The EPA+DHA content was 20% lower in cases than controls (3.4+/-1.6 vs. 4.25+/-2.0%, pACS event was 0.58 (95% CI 0.42-0.80), in the intermediate EPA+DHA group and was 0.31 (95% CI 0.14-0.67; p for trend ACS case status increased incrementally as the EPA+DHA content decreased suggesting that low EPA+DHA may be associated with increased risk for ACS.

  12. Effect of tropicamide on ocular blood flow in the rabbit

    International Nuclear Information System (INIS)

    Delgado, D.; Michel, P.; Jaanus, S.D.

    1982-01-01

    Intracardiac injection of 15 microspheres labeled with 85 Sr (strontium) and 141 Ce (cerium) were used to determine ocular blood flow in seven rabbits before and 25 min after bilateral application of tropicamide to the cornea. By using two different isotopes distinguishable under gammaspectrometry, each animal served as its own control. After administration of two drops of 1% tropicamide, no significant difference in blood flow between treated and untreated eyes was observed

  13. Chronic Stress Impairs Collateral Blood Flow Recovery in Aged Mice

    Science.gov (United States)

    2014-10-15

    of oxidative stress in atherosclerosis. American of Journal in Cardiology , 91, 7A–11A. 11. Balkaya, M., Prinz, V., Custodis, F., et al. (2011...femoral artery occlusion (Figs. 2 and 5). Fig. 2 Blood flow recovery measurement after FAL. Blood flow mea- sured for control ( open circle) and stressed...peripheral arterial disease. Journal General and International Medication, 18(6), 461–467. 5. Yan, L. L., Liu, K., Matthews, K. A., et al. (2003). Psychosocial

  14. Blood flow rate measurements with indicator techniques revisited

    DEFF Research Database (Denmark)

    Sejrsen, Per; Bülow, Jens

    2009-01-01

    In view of the emerging role, disturbances in regional blood flow rate seem to play in the pathogenesis of the metabolic syndrome; we review the concepts of the classical indicator dilution and washout techniques used for determinations of regional blood flow rate. Prerequisites, assumptions......, necessary precautions for the application of these experimental techniques are emphasized. Special attention has been carried out to elucidate the consequence of a choice of indicators having a large distribution volume in the tissues....

  15. Non-invasive pulmonary blood flow analysis and blood pressure mapping derived from 4D flow MRI

    Science.gov (United States)

    Delles, Michael; Rengier, Fabian; Azad, Yoo-Jin; Bodenstedt, Sebastian; von Tengg-Kobligk, Hendrik; Ley, Sebastian; Unterhinninghofen, Roland; Kauczor, Hans-Ulrich; Dillmann, Rüdiger

    2015-03-01

    In diagnostics and therapy control of cardiovascular diseases, detailed knowledge about the patient-specific behavior of blood flow and pressure can be essential. The only method capable of measuring complete time-resolved three-dimensional vector fields of the blood flow velocities is velocity-encoded magnetic resonance imaging (MRI), often denoted as 4D flow MRI. Furthermore, relative pressure maps can be computed from this data source, as presented by different groups in recent years. Hence, analysis of blood flow and pressure using 4D flow MRI can be a valuable technique in management of cardiovascular diseases. In order to perform these tasks, all necessary steps in the corresponding process chain can be carried out in our in-house developed software framework MEDIFRAME. In this article, we apply MEDIFRAME for a study of hemodynamics in the pulmonary arteries of five healthy volunteers. The study included measuring vector fields of blood flow velocities by phase-contrast MRI and subsequently computing relative blood pressure maps. We visualized blood flow by streamline depictions and computed characteristic values for the left and the right pulmonary artery (LPA and RPA). In all volunteers, we observed a lower amount of blood flow in the LPA compared to the RPA. Furthermore, we visualized blood pressure maps using volume rendering and generated graphs of pressure differences between the LPA, the RPA and the main pulmonary artery. In most volunteers, blood pressure was increased near to the bifurcation and in the proximal LPA, leading to higher average pressure values in the LPA compared to the RPA.

  16. Corticosteroid Reduces Blood Flow to Femoral Heads in Rabbits.

    Science.gov (United States)

    Hou, S.M.; Liu, T.K.; Kao, M.C.

    1994-12-01

    Avascular necrosis of the femoral head is one of the common problems in orthopedic practice in Taiwan. The subchondral bone loses its blood supply which weakens its biomechanical support. Steroid overuse is one of many possible etiologies in reducing blood flow to the femoral head. Laser Doppler velocimeter is a precise monitor of regional blood flow of bone which is expressed in perfusion units (PU). In the control group the rabbits were injected with normal saline and there were no statistical differences between blood flow to the right hip (39.26 +/- 5.64 PU) and left hip (38.58 +/- 4.35 PU). In group B a weekly injection of methylprednisolone into rabbits for 6 weeks demonstrated the reduction of blood flow of femoral head (24.74 +/- 3.13 PU) by the laser Doppler velocimeter. The flow decreased further (15.93 +/- 2.33 PU) by 12 weeks of steroid treatment. In group C after a weekly injection of steroid for 6 weeks the flow became 31.63 +/- 4.79 PU. The steroid was then discontinued for 3 weeks and the flow was 34.6 +/- 1.34 PU. In group D the blood flow was 25.89 +/- 4.01 PU after 6 weeks of steroid treatment and we stopped the steroid for 6 weeks, the blood flow became 29.86 +/- 2.59 PU. The merit of our experiment established a model of study in avascular necrosis of the femoral head in rabbits. Copyright 1994 S. Karger AG, Basel

  17. Establishing the diffuse correlation spectroscopy signal relationship with blood flow.

    Science.gov (United States)

    Boas, David A; Sakadžić, Sava; Selb, Juliette; Farzam, Parisa; Franceschini, Maria Angela; Carp, Stefan A

    2016-07-01

    Diffuse correlation spectroscopy (DCS) measurements of blood flow rely on the sensitivity of the temporal autocorrelation function of diffusively scattered light to red blood cell (RBC) mean square displacement (MSD). For RBCs flowing with convective velocity [Formula: see text], the autocorrelation is expected to decay exponentially with [Formula: see text], where [Formula: see text] is the delay time. RBCs also experience shear-induced diffusion with a diffusion coefficient [Formula: see text] and an MSD of [Formula: see text]. Surprisingly, experimental data primarily reflect diffusive behavior. To provide quantitative estimates of the relative contributions of convective and diffusive movements, we performed Monte Carlo simulations of light scattering through tissue of varying vessel densities. We assumed laminar vessel flow profiles and accounted for shear-induced diffusion effects. In agreement with experimental data, we found that diffusive motion dominates the correlation decay for typical DCS measurement parameters. Furthermore, our model offers a quantitative relationship between the RBC diffusion coefficient and absolute tissue blood flow. We thus offer, for the first time, theoretical support for the empirically accepted ability of the DCS blood flow index ([Formula: see text]) to quantify tissue perfusion. We find [Formula: see text] to be linearly proportional to blood flow, but with a proportionality modulated by the hemoglobin concentration and the average blood vessel diameter.

  18. The clinical use of the device for flowing blood irradiation

    International Nuclear Information System (INIS)

    Arutyunov, A.S.; Karasev, A.B.; Kovalev, O.I.; Pisarevskij, A.A.; Skobennikov, A.K.; Trofimov, V.I.; Khaskel'berg, N.G.

    1988-01-01

    The indications and possibilities of using the device for flowing extracorporeal ultraviolet radiation of blood are considered. The uniformity of the radiation of blood in the proposed device provides an annular gap of the quartz dish with the partition in the shape of a spiral. It makes it possible to expose a larger part of the blood content of an organism simultaneously making use of various perfused methods of its detoxication

  19. Quantitative assessment of limb blood flow using Tc-99m labeled red blood cells

    International Nuclear Information System (INIS)

    Itoh, Kazuo; Shougase, Takashi; Kawamura, Naoyuki; Tsukamoto, Eriko; Nakada, Kunihiro; Sakuma, Makoto; Furudate, Masayori

    1987-01-01

    A quantitative assessment of limb blood flow using a non-diffusible radioindicator, Tc-99m labeled red blood cells, was reported. This was an application of venous occlusion plethysmography using radionuclide which was originally proposed by M. Fukuoka et al. The peripheral blood flow (mean ± s.e.) of 30 legs in a normal control group was 1.87 ± 0.08 ml/100 ml/min. In heart diseases (46 legs), it was 1.49 ± 0.13 ml/100 ml/min. The limb blood flow between a control group and heart diseases was statistically significant (p < 0.01) in the t-test. The peripheral blood flow at rest between diseased legs and normal legs in occlusive arterial disorders was also statistically significant (p < 0.01) in a paired t-test. RAVOP was done after the completion of objective studies such as radionuclide angiography or ventriculography. Technique and calculation of a blood flow were very easy and simple. RAVOP study which was originally proposed by Fukuoka et al. was reappraised to be hopeful for quantitative measurement of limb blood flow as a non-invasive technique using Tc-99m labeled red blood cells. (author)

  20. Prognostic Value of Transthoracic Doppler Echocardiography Coronary Flow Velocity Reserve in Patients with Nonculprit Stenosis of Intermediate Severity Early after Primary Percutaneous Coronary Intervention.

    Science.gov (United States)

    Tesic, Milorad; Djordjevic-Dikic, Ana; Giga, Vojislav; Stepanovic, Jelena; Dobric, Milan; Jovanovic, Ivana; Petrovic, Marija; Mehmedbegovic, Zlatko; Milasinovic, Dejan; Dedovic, Vladimir; Zivkovic, Milorad; Juricic, Stefan; Orlic, Dejan; Stojkovic, Sinisa; Vukcevic, Vladan; Stankovic, Goran; Nedeljkovic, Milan; Ostojic, Miodrag; Beleslin, Branko

    2018-04-03

    Treatment of nonculprit coronary stenosis during primary percutaneous coronary intervention in patients with ST-segment elevation myocardial infarction may be beneficial, but the mode and timing of the intervention are still controversial. The aim of this study was to examine the significance and prognostic value of preserved coronary flow velocity reserve (CFVR) in patients with nonculprit intermediate stenosis early after primary percutaneous coronary intervention. Two hundred thirty patients with remaining intermediate (50%-70%) stenosis of non-infarct-related arteries, in whom CFVR was performed within 7 days after primary percutaneous coronary intervention, were prospectively enrolled. Twenty patients with reduced CFVR and positive results on stress echocardiography or impaired fractional flow reserve underwent revascularization and were not included in further analysis. The final study population of 210 patients (mean age, 58 ± 10 years; 162 men) was divided into two groups on the basis of CFVR: group 1, CFVR > 2 (n = 174), and group 2, CFVR ≤ 2 (n = 36). Cardiac death, nonfatal myocardial infarction, and revascularization of the evaluated vessel were considered adverse events. Mean follow-up duration was 47 ± 16 months. Mean CFVR for the whole group was 2.36 ± 0.40. There were six adverse events (3.4%) related to the nonculprit coronary artery in group 1, including one cardiac death, one ST-segment elevation myocardial infarction, and four revascularizations. In group 2, there were 30 adverse events (83.3%, P  2 of the intermediate nonculprit coronary lesion, deferral of revascularization is safe and associated with excellent long-term clinical outcomes. Copyright © 2018 American Society of Echocardiography. Published by Elsevier Inc. All rights reserved.

  1. Myocardial distribution of I131-labeled hexadecenoic acid in relation to the dog local coronary flow

    International Nuclear Information System (INIS)

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

    1981-01-01

    20 anesthetized and thoracotomized dogs are studied. The local myocardial blood flow is measured with sup(99m)Tc human albumin microspheres. The intramyocardial distribution of the 16-I(131)-9-hexadecenoic acid in relation to local blood flow is studied in basal conditions (7 dogs), after experimental infarction (6 dogs) and postischemic reactive hyperhemia (7 dogs). We conclude that during basal condition, after infarction but not during reactive hyperhemia, the distribution of the labeled fatty acid reflect the local variations of blood flow [fr

  2. Association of coronary ischemia estimated by fractional flow reserve and psychological characteristics of patients

    Directory of Open Access Journals (Sweden)

    Miodrag Jovan Sreckovic

    2017-05-01

    Full Text Available Introduction : Psychological characteristics of patients, depression, stress and anxiety are recognized as important confounding risk factors for ischemic heart disease. However, the impact of psychological characteristics on coronary ischemia and vice versa remain poorly understood. Aim: To demonstrate the interplay of psychological characteristics, depression, stress and anxiety with coronary ischemia estimated with fractional flow reserve (FFR. Material and methods : From 2014 to 2016, 147 patients who were planned for FFR measurement were included in this study. Psychological characteristics of patients were evaluated using the Depression, Anxiety and Stress Scale 21 items (DASS 21 self-report questionnaire. Results : Comparing the FFR ischemic vs. FFR non-ischemic groups, a significant difference was observed regarding results achieved for the depression, anxiety and stress scales. Multivariate logistic regression analysis was used to model the correlation between FFR and the DAS scale. It was clear, when controlling for previous myocardial infarction, that FFR was significant in all analyses. However, when the Canadian Cardiovascular Society grading of angina pectoris (CCS class was entered in the model, FFR was not a significant predictor of anxiety, but was significant in other analysis. Conclusions : Higher degrees of the psychological characteristics depression, stress and anxiety were observed in the group of patients with coronary ischemia, corresponding to lower fractional flow values.

  3. PIV-validated numerical modeling of pulsatile flows in distal coronary end-to-side anastomoses.

    Science.gov (United States)

    Xiong, F L; Chong, C K

    2007-01-01

    This study employed particle image velocimetry (PIV) to validate a numerical model in a complementary approach to quantify hemodynamic factors in distal coronary anastomoses and to gain more insights on their relationship with anastomotic geometry. Instantaneous flow fields and wall shear stresses (WSS) were obtained from PIV measurement in a modified life-size silastic anastomosis model adapted from a conventional geometry by incorporating a smooth graft-artery transition. The results were compared with those predicted by a concurrent numerical model. The numerical method was then used to calculate cycle-averaged WSS (WSS(cyc)) and spatial wall shear stress gradient (SWSSG), two critical hemodynamic factors in the pathogenesis of intimal thickening (IT), to compare the conventional and modified geometries. Excellent qualitative agreement and satisfactory quantitative agreement with averaged normalized error in WSS between 0.8% and 8.9% were achieved between the PIV experiment and numerical model. Compared to the conventional geometry, the modified geometry produces a more uniform WSS(cyc) distribution eliminating both high and low WSS(cyc) around the toe, critical in avoiding IT. Peak SWSSG on the artery floor of the modified model is less than one-half that in the conventional case, and high SWSSG at the toe is eliminated. The validated numerical model is useful for modeling unsteady coronary anastomotic flows and elucidating the significance of geometry regulated hemodynamics. The results suggest the clinical relevance of constructing smooth graft-artery transition in distal coronary anastomoses to improve their hemodynamic performance.

  4. Numerical analysis of blood flow in realistic arteries subjected to strong non-uniform magnetic fields

    International Nuclear Information System (INIS)

    Kenjeres, Sasa

    2008-01-01

    The paper reports on a comprehensive mathematical model for simulations of blood flow under the presence of strong non-uniform magnetic fields. The model consists of a set of Navier-Stokes equations accounting for the Lorentz and magnetisation forces, and a simplified set of Maxwell's equations (Biot-Savart/Ampere's law) for treating the imposed magnetic fields. The relevant hydrodynamic and electromagnetic properties of human blood were taken from the literature. The model is then validated for different test cases ranging from a simple cylindrical geometry to real-life right-coronary arteries in humans. The time-dependency of the wall-shear-stress for different stenosis growth rates and the effects of the imposed strong non-uniform magnetic fields on the blood flow pattern are presented and analysed. It is concluded that an imposed non-uniform magnetic field can create significant changes in the secondary flow patterns, thus making it possible to use this technique for optimisations of targeted drug delivery

  5. CHARACTERIZATION OF RENAL BLOOD FLOW REGULATION BASED ON WAVELET COEFFICIENTS

    DEFF Research Database (Denmark)

    Pavlov, A.N.; Pavlova, O.N.; Mosekilde, Erik

    2010-01-01

    The purpose of this study is to demonstrate the possibility of revealing new characteristic features of renal blood flow autoregulation in healthy and pathological states through the application of discrete wavelet transforms to experimental time series for normotensive and hypertensive rats....... A reduction in the variability of the wavelet coefficients in hypertension is observed at both the microscopic level of the blood flow in efferent arterioles of individual nephrons and at the macroscopic level of the blood pressure in the main arteries. The reduction is manifest in both of the main frequency...

  6. Abnormality in cerebellar blood flow in solo vertigo patients

    Energy Technology Data Exchange (ETDEWEB)

    Nagahori, Takeshi [Shakaihoken Takaoka Hospital, Toyama (Japan); Nishijima, Michiharu; Endo, Shunro; Takaku, Akira

    1997-03-01

    Little is known about the blood flow of the vertebrobasilar system as a cause of vertigo and dizziness. We used Xe-CT to study cerebellar blood flow in 53 patients who ranged in age from 35 to 85 years. The patients were divided into two groups. One of them was the vertigo group that comprised 28 patients with rotatory sensation, and the other, the non-vertigo group of 25 patients with a sensation other than rotation. At the stage of severe symptoms, there was decreased cerebellar blood flow in all patients of both, the vertigo and the non-vertigo groups, and a decrease in the bilateral cerebellar hemisphere was observed in five patients and in a unilateral hemisphere in three patients of the vertigo group. By comparison, in the non-vertigo group, unilateral decrease of cerebellar blood flow was observed in only one patient, and a bilateral decrease in five. At the stage of severe symptoms, the mean regional cerebellar blood flow was 40.5{+-}8.0 ml/100 g/min (n=16 sides) in the vertigo group and 45.3{+-}9.5 ml/100 g/min (n=12 sides) in the non-vertigo group. At the stage of moderate symptoms, blood flow image was normal in four of 14 vertigo patients and in seven of 12 non-vertigo patients. The mean regional blood flow was 47.8{+-}8.6 ml/100 g/min (n=28 sides) in the vertigo group and 47.1{+-}5.1 ml/100 g/min (n=24 sides) in the non-vertigo group. At the asymptomatic stage, a high proportion of normal blood flow images (nine of 16 vertigo patients and 10 of 10 non-vertigo patients) was observed. The mean regional cerebellar blood flow was 51.6{+-}10.7 ml/100 g/min (n=32 sides) in the vertigo group and 52.8{+-}8.5 ml/100 g/min (n=20 sides) in the non-vertigo group. This study demonstrates that a unilateral or bilateral decrease in blood flow of the vertebrobasilar system may cause vertigo and dizziness. It also shows that Xe-CT of the cerebellum may be a valuable examination modality for the diagnosis and treatment of vertigo and dizziness. (author)

  7. Abnormality in cerebellar blood flow in solo vertigo patients

    International Nuclear Information System (INIS)

    Nagahori, Takeshi; Nishijima, Michiharu; Endo, Shunro; Takaku, Akira

    1997-01-01

    Little is known about the blood flow of the vertebrobasilar system as a cause of vertigo and dizziness. We used Xe-CT to study cerebellar blood flow in 53 patients who ranged in age from 35 to 85 years. The patients were divided into two groups. One of them was the vertigo group that comprised 28 patients with rotatory sensation, and the other, the non-vertigo group of 25 patients with a sensation other than rotation. At the stage of severe symptoms, there was decreased cerebellar blood flow in all patients of both, the vertigo and the non-vertigo groups, and a decrease in the bilateral cerebellar hemisphere was observed in five patients and in a unilateral hemisphere in three patients of the vertigo group. By comparison, in the non-vertigo group, unilateral decrease of cerebellar blood flow was observed in only one patient, and a bilateral decrease in five. At the stage of severe symptoms, the mean regional cerebellar blood flow was 40.5±8.0 ml/100 g/min (n=16 sides) in the vertigo group and 45.3±9.5 ml/100 g/min (n=12 sides) in the non-vertigo group. At the stage of moderate symptoms, blood flow image was normal in four of 14 vertigo patients and in seven of 12 non-vertigo patients. The mean regional blood flow was 47.8±8.6 ml/100 g/min (n=28 sides) in the vertigo group and 47.1±5.1 ml/100 g/min (n=24 sides) in the non-vertigo group. At the asymptomatic stage, a high proportion of normal blood flow images (nine of 16 vertigo patients and 10 of 10 non-vertigo patients) was observed. The mean regional cerebellar blood flow was 51.6±10.7 ml/100 g/min (n=32 sides) in the vertigo group and 52.8±8.5 ml/100 g/min (n=20 sides) in the non-vertigo group. This study demonstrates that a unilateral or bilateral decrease in blood flow of the vertebrobasilar system may cause vertigo and dizziness. It also shows that Xe-CT of the cerebellum may be a valuable examination modality for the diagnosis and treatment of vertigo and dizziness. (author)

  8. Echocardiographic and hemodynamic determinants of right coronary artery flow reserve and phasic flow pattern in advanced non-ischemic cardiomyopathy

    Directory of Open Access Journals (Sweden)

    Mady Charles

    2007-09-01

    Full Text Available Abstract Background In patients with advanced non-ischemic cardiomyopathy (NIC, right-sided cardiac disturbances has prognostic implications. Right coronary artery (RCA flow pattern and flow reserve (CFR are not well known in this setting. The purpose of this study was to assess, in human advanced NIC, the RCA phasic flow pattern and CFR, also under right-sided cardiac disturbances, and compare with left coronary circulation. As well as to investigate any correlation between the cardiac structural, mechanical and hemodynamic parameters with RCA phasic flow pattern or CFR. Methods Twenty four patients with dilated severe NIC were evaluated non-invasively, even by echocardiography, and also by cardiac catheterization, inclusive with Swan-Ganz catheter. Intracoronary Doppler (Flowire data was obtained in RCA and left anterior descendent coronary artery (LAD before and after adenosine. Resting RCA phasic pattern (diastolic/systolic was compared between subgroups with and without pulmonary hypertension, and with and without right ventricular (RV dysfunction; and also with LAD. RCA-CFR was compared with LAD, as well as in those subgroups. Pearson's correlation analysis was accomplished among echocardiographic (including LV fractional shortening, mass index, end systolic wall stress more hemodynamic parameters with RCA phasic flow pattern or RCA-CFR. Results LV fractional shortening and end diastolic diameter were 15.3 ± 3.5 % and 69.4 ± 12.2 mm. Resting RCA phasic pattern had no difference comparing subgroups with vs. without pulmonary hypertension (1.45 vs. 1.29, p = NS either with vs. without RV dysfunction (1.47 vs. 1.23, p = NS; RCA vs. LAD was 1.35 vs. 2.85 (p Conclusion In patients with chronic advanced NIC, RCA phasic flow pattern has a mild diastolic predominance, less marked than in LAD, with no effects from pulmonary artery hypertension or RV dysfunction. There is no significant correlation between any cardiac mechanical-structural or

  9. The effect of ultrasound on arterial blood flow: 1. Steady fully developed flow

    International Nuclear Information System (INIS)

    Bestman, A.R.

    1990-12-01

    The paper models the effects of ultrasound heating of the tissues and the resultant perturbation on blood flow in the arteries and veins. It is assumed that the blood vessel is rigid and the undisturbed flow is fully developed. Acoustical perturbation on this Poiseuille flow, for the general three-dimensional flow with heat transfer in an infinitely long pipe is considered. Closed form analytical solutions are obtained to the problem. It is discovered that the effects of the ultrasound heating are concentrated at the walls of the blood vessels. (author). 4 refs

  10. Quantification of complex blood flow using real-time in vivo vector flow ultrasound

    DEFF Research Database (Denmark)

    Pedersen, Mads Møller; Pihl, Michael Johannes; Haugaard, Per

    2010-01-01

    A quantitative method for distinguishing complex from non-complex flow patterns in ultrasound is presented. A new commercial BK Medical ultrasound scanner uses the Transverse Oscillation vector flow technique for visualising flow patterns in real-time. In vivo vector flow data of the blood flow...... patterns of the common carotid artery and the carotid bulb were obtained simultaneously as the basis for quantifying complex flow. The carotid bifurcation of two healthy volunteers were scanned. The presence of complex flow patterns from eight cardiac cycles were evaluated by three experts in medical...... for automatic detection of complex flow patterns....

  11. Transplacental diffusion and blood flow of gravid bovine uterus

    International Nuclear Information System (INIS)

    Reynolds, L.P.; Ferrell, C.L.; Ford, S.P.

    1985-01-01

    Electromagnetic blood flow transducers and uterine arterial, uterine venous, umbilical venous, fetal femoral arterial, and fetal femoral venous catheters were implanted in 11 cows on day 161 +/- 4 of gestation. Antipyrine (0.66 M) plus NaCl (0.16 M) dissolved in deuterium oxide (D 2 O), or H 2 O, was infused at a constant rate into the fetal femoral vein catheter. Concentrations of antipyrine and D 2 O in uterine arterial and venous blood and antipyrine in fetal arterial and umbilical venous blood, as well as middle uterine arterial blood flow (electromagnetic transducer), were determined. Antipyrine and D 2 O gave similar estimates (steady-state diffusion method) of gravid uterine blood flow. In addition, the slope of the regression of D 2 O on antipyrine estimates was not different from one. Electromagnetic transducers gave estimates of uterine blood flow that were 32-42% of those obtained with steady-state diffusion but were correlated with estimates obtained by use of both antipyrine and D 2 O. The transplacental clearance rate of antipyrine was similar (per kg placenta) to that observed in ewes. It was suggested that the maternal and fetal microvasculatures of the bovine placenta could have a concurrent arrangement with vascular shunts or maldistribution of flows, as has been suggested for the ewe

  12. The effects of hypoxemia on myocardial blood flow during exercise.

    Science.gov (United States)

    Paridon, S M; Bricker, J T; Dreyer, W J; Reardon, M; Smith, E O; Porter, C B; Michael, L; Fisher, D J

    1989-03-01

    We evaluated the adequacy of regional and transmural blood flow during exercise and rapid pacing after 1 wk of hypoxemia. Seven mature mongrel dogs were made hypoxemic (mean O2 saturation = 72.4%) by anastomosis of left pulmonary artery to left atrial appendage. Catheters were placed in the left atrium, right atrium, pulmonary artery, and aorta. Atrial and ventricular pacing wires were placed. An aortic flow probe was placed to measure cardiac output. Ten nonshunted dogs, similarly instrumented, served as controls. Recovery time was approximately 1 wk. Cardiac output, mean aortic pressure, and oxygen saturation were measured at rest, with ventricular pacing, atrial pacing, and with treadmill exercise. Ventricular and atrial pace and exercise were at a heart rate of 200. Right ventricular free wall, left ventricular free wall, and septal blood flow were measured with radionuclide-labeled microspheres. Cardiac output, left atrial blood pressure, and aortic blood pressure were similar between the two groups of dogs in all testing states. Myocardial blood flow was significantly higher in the right and left ventricular free wall in the hypoxemic animals during resting and exercise testing states. Myocardial oxygen delivery was similar between the two groups of animals. Pacing resulted in an increase in myocardial blood flow in the control animals but not the hypoxemic animals.(ABSTRACT TRUNCATED AT 250 WORDS)

  13. Regional cerebral blood flow in focal cortical epilepsy

    DEFF Research Database (Denmark)

    Hougaard, Kristina Dupont; Oikawa, T; Sveinsdottir, E

    1976-01-01

    Regional cerebral blood flow (rCBF) was studied in ten patients with focal cortical epilepsy. The blood flow was measured by the intra-arterial injection of xenon 133 (133Xe), and the isotope clearance was recorded by a multidetector scintillation camera with 254 detectors. Three patients were....... This finding accords with earlier studies. All nine patients studied in the interictal phase showed, either spontaneously or during activation by intermittent light, focal flow increases in areas presumed to comprise the epileptic focus. These interictal hyperemic foci probably reflect subictal neuronal...

  14. Viscoelastic capillary flow: the case of whole blood

    Directory of Open Access Journals (Sweden)

    David Rabaud

    2016-07-01

    Full Text Available The dynamics of spontaneous capillary flow of Newtonian fluids is well-known and can be predicted by the Lucas-Washburn-Rideal (LWR law. However a wide variety of viscoelastic fluids such as alginate, xanthan and blood, does not exhibit the same Newtonian behavior.In this work we consider the Herschel-Bulkley (HB rheological model and Navier-Stokes equation to derive a generic expression that predicts the capillary flow of non-Newtonian fluids. The Herschel-Bulkley rheological model encompasses a wide variety of fluids, including the Power-law fluids (also called Ostwald fluids, the Bingham fluids and the Newtonian fluids. It will be shown that the proposed equation reduces to the Lucas-Washburn-Rideal law for Newtonian fluids and to the Weissenberg-Rabinowitsch-Mooney (WRM law for power-law fluids. Although HB model cannot reduce to Casson’s law, which is often used to model whole blood rheology, HB model can fit the whole blood rheology with the same accuracy.Our generalized expression for the capillary flow of non-Newtonian fluid was used to accurately fit capillary flow of whole blood. The capillary filling of a cylindrical microchannel by whole blood was monitored. The blood first exhibited a Newtonian behavior, then after 7 cm low shear stress and rouleaux formation made LWR fails to fit the data: the blood could not be considered as Newtonian anymore. This non-Newtonian behavior was successfully fit by the proposed equation.

  15. Age and gender related differences in aortic blood flow

    DEFF Research Database (Denmark)

    Traberg, Marie Sand; Pedersen, Mads Møller; Hemmsen, Martin Christian

    2012-01-01

    The abdominal aorta (AA) is predisposed to development of abdominal aneurysms (AAA), a focal dilatation of the artery with fatal consequences if left untreated. The blood flow patterns in the AA is thought to play an important role in the development of AAA. The purpose of this work is to investi......The abdominal aorta (AA) is predisposed to development of abdominal aneurysms (AAA), a focal dilatation of the artery with fatal consequences if left untreated. The blood flow patterns in the AA is thought to play an important role in the development of AAA. The purpose of this work...... is to investigate the blood flow pat- terns within a group of healthy volunteers (4 females, 7 males) aged 23 to 76 years to identify changes and differences related to age and gender. The healthy volunteers were categorized by gender (male/female) and age (below/above 35 years). Subject-specific flow and geometry...... to elderly. Thus, changes in blood flow patterns in the AA related to age and gender is observed. Further investigations are needed to determine the relation between changes in blood flow patterns and AAA development....

  16. 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.)

  17. Prediction of blood pressure and blood flow in stenosed renal arteries using CFD

    Science.gov (United States)

    Jhunjhunwala, Pooja; Padole, P. M.; Thombre, S. B.; Sane, Atul

    2018-04-01

    In the present work an attempt is made to develop a diagnostive tool for renal artery stenosis (RAS) which is inexpensive and in-vitro. To analyse the effects of increase in the degree of severity of stenosis on hypertension and blood flow, haemodynamic parameters are studied by performing numerical simulations. A total of 16 stenosed models with varying degree of stenosis severity from 0-97.11% are assessed numerically. Blood is modelled as a shear-thinning, non-Newtonian fluid using the Carreau model. Computational Fluid Dynamics (CFD) analysis is carried out to compute the values of flow parameters like maximum velocity and maximum pressure attained by blood due to stenosis under pulsatile flow. These values are further used to compute the increase in blood pressure and decrease in available blood flow to kidney. The computed available blood flow and secondary hypertension for varying extent of stenosis are mapped by curve fitting technique using MATLAB and a mathematical model is developed. Based on these mathematical models, a quantification tool is developed for tentative prediction of probable availability of blood flow to the kidney and severity of stenosis if secondary hypertension is known.

  18. Nephron blood flow dynamics measured by laser speckle contrast imaging

    DEFF Research Database (Denmark)

    von Holstein-Rathlou, Niels-Henrik; Sosnovtseva, Olga V; Pavlov, Alexey N

    2011-01-01

    Tubuloglomerular feedback (TGF) has an important role in autoregulation of renal blood flow and glomerular filtration rate (GFR). Because of the characteristics of signal transmission in the feedback loop, the TGF undergoes self-sustained oscillations in single-nephron blood flow, GFR, and tubular...... simultaneously. The interacting nephron fields are likely to be more extensive. We have turned to laser speckle contrast imaging to measure the blood flow dynamics of 50-100 nephrons simultaneously on the renal surface of anesthetized rats. We report the application of this method and describe analytic...... pressure and flow. Nephrons interact by exchanging electrical signals conducted electrotonically through cells of the vascular wall, leading to synchronization of the TGF-mediated oscillations. Experimental studies of these interactions have been limited to observations on two or at most three nephrons...

  19. Skeletal blood flow: implications for bone-scan interpretation

    International Nuclear Information System (INIS)

    Charkes, N.D.

    1980-01-01

    The dispersion of the skeleton throughout the body and its complex vascular anatomy require indirect methods for the measurement of skeletal blood flow. The results of one such method, compartmental analysis of skeletal tracer kinetics, are presented. The assumptions underlying the models were tested in animals and found to be in agreement with experimental observations. Based upon the models and the experimental results, inferences concerning bone-scan interpretation can be drawn: decreased cardiac output produces low-contrast (technically poor) scans; decreased skeletal flow produces photon-deficient lesions; increase of cardiac output or of generalized systemic blood flow is undetectable 1 to 2 h after dose; increased local skeletal blood flow results from disturbance of the bone microvasculature and can occur from neurologic (sympatholytic) disorders or in association with focal abnormalities that also incite the formation of reactive bone (e.g., metastasis, fracture, etc.). Mathematical solutions of tracer kinetic data thus become relevant to bone-scan interpretation

  20. Intrinsic regulation of blood flow in adipose tissue

    DEFF Research Database (Denmark)

    Henriksen, O; Nielsen, Steen Levin; Paaske, W

    1976-01-01

    Previous studies on intact human subcutaneous tissue have shown, that blood flow remains constant during minor changes in perfusion pressure. This so-called autoregulatory response has not been demonstrable in isolated preparations of adipose tissue. In the present study on isolated, denervated...... subcutaneous tissue in female rabbits only 2 of 12 expts. revealed an autoregulatory response during reduction in arterial perfusion pressure. Effluent blood flow from the tissue in the control state was 15.5 ml/100 g-min (S.D. 6.4, n = 12) corresponding to slight vasodilatation of the exposed tissue...... vasoconstriction with pronounced flow reduction. These two reactions may be important for local regulation of blood flow in subcutaneous tissue during orthostatic changes in arterial and venous pressure. It is concluded that the response in adipose tissue to changes in arterial pressure (autoregulation), venous...

  1. Supraorbital cutaneous blood flow rate during carotid endarterectomy

    DEFF Research Database (Denmark)

    Hove, Jens D; Rosenberg, Iben; Sejrsen, Per

    2006-01-01

    : The supraorbital cutaneous blood flow rate was measured by the application of heat to the skin and following the subsequent dissipation of the heat in seven patients undergoing carotid endarterectomy. At the same time, the oxygenation in the right and left frontal region was monitored by near-infrared spectroscopy......BACKGROUND: The supraorbital skin region is supplied by the supraorbital artery, which is a branch of the internal carotid artery. The supraorbital cutaneous blood flow rate may therefore be influenced by changes in the internal carotid artery flow during carotid endarterectomy. METHODS...... (NIRS). RESULTS: During cross-clamping of the carotid artery, the ipsilateral NIRS-determined frontal oxygenation tended to decrease [67 +/- 13% to 61 +/- 11% (P = 0.06); contralateral 68 +/- 11% to 66 +/- 8%] as did the supraorbital cutaneous blood flow rate from 56 +/- 23 to 44 +/- 7 ml 100 g(-1) min...

  2. Pulsatile blood flow, shear force, energy dissipation and Murray's Law

    Directory of Open Access Journals (Sweden)

    Bengtsson Hans-Uno

    2006-08-01

    Full Text Available Abstract Background Murray's Law states that, when a parent blood vessel branches into daughter vessels, the cube of the radius of the parent vessel is equal to the sum of the cubes of the radii of daughter blood vessels. Murray derived this law by defining a cost function that is the sum of the energy cost of the blood in a vessel and the energy cost of pumping blood through the vessel. The cost is minimized when vessel radii are consistent with Murray's Law. This law has also been derived from the hypothesis that the shear force of moving blood on the inner walls of vessels is constant throughout the vascular system. However, this derivation, like Murray's earlier derivation, is based on the assumption of constant blood flow. Methods To determine the implications of the constant shear force hypothesis and to extend Murray's energy cost minimization to the pulsatile arterial system, a model of pulsatile flow in an elastic tube is analyzed. A new and exact solution for flow velocity, blood flow rate and shear force is derived. Results For medium and small arteries with pulsatile flow, Murray's energy minimization leads to Murray's Law. Furthermore, the hypothesis that the maximum shear force during the cycle of pulsatile flow is constant throughout the arterial system implies that Murray's Law is approximately true. The approximation is good for all but the largest vessels (aorta and its major branches of the arterial system. Conclusion A cellular mechanism that senses shear force at the inner wall of a blood vessel and triggers remodeling that increases the circumference of the wall when a shear force threshold is exceeded would result in the observed scaling of vessel radii described by Murray's Law.

  3. Impact of pacing modality and biventricular pacing on cardiac output and coronary conduit flow in the post-cardiotomy patient.

    LENUS (Irish Health Repository)

    Healy, David G

    2012-02-03

    We have previously demonstrated the role of univentricular pacing modalities in influencing coronary conduit flow in the immediate post-operative period in the cardiac surgery patient. We wanted to determine the mechanism of this improved coronary conduit and, in addition, to explore the possible benefits with biventricular pacing. Sixteen patients undergoing first time elective coronary artery bypass grafting who required pacing following surgery were recruited. Comparison of cardiac output and coronary conduit flow was performed between VVI and DDD pacing with a single right ventricular lead and biventricular pacing lead placement. Cardiac output was measured using arterial pulse waveform analysis while conduit flow was measured using ultrasonic transit time methodology. Cardiac output was greatest with DDD pacing using right ventricular lead placement only [DDD-univentricular 5.42 l (0.7), DDD-biventricular 5.33 l (0.8), VVI-univentricular 4.71 l (0.8), VVI-biventricular 4.68 l (0.6)]. DDD-univentricular pacing was significantly better than VVI-univentricular (P=0.023) and VVI-biventricular pacing (P=0.001) but there was no significant advantage to DDD-biventricular pacing (P=0.45). In relation to coronary conduit flow, DDD pacing again had the highest flow [DDD-univentricular 55 ml\\/min (24), DDD-biventricular 52 ml\\/min (25), VVI-univentricular 47 ml\\/min (23), VVI-biventricular 50 ml\\/min (26)]. DDD-univentricular pacing was significantly better than VVI-univentricular (P=0.006) pacing but not significantly different to VVI-biventricular pacing (P=0.109) or DDD-biventricular pacing (P=0.171). Pacing with a DDD modality offers the optimal coronary conduit flow by maximising cardiac output. Biventricular lead placement offered no significant benefit to coronary conduit flow or cardiac output.

  4. Partitioning of red blood cell aggregates in bifurcating microscale flows

    Science.gov (United States)

    Kaliviotis, E.; Sherwood, J. M.; Balabani, S.

    2017-03-01

    Microvascular flows are often considered to be free of red blood cell aggregates, however, recent studies have demonstrated that aggregates are present throughout the microvasculature, affecting cell distribution and blood perfusion. This work reports on the spatial distribution of red blood cell aggregates in a T-shaped bifurcation on the scale of a large microvessel. Non-aggregating and aggregating human red blood cell suspensions were studied for a range of flow splits in the daughter branches of the bifurcation. Aggregate sizes were determined using image processing. The mean aggregate size was marginally increased in the daughter branches for a range of flow rates, mainly due to the lower shear conditions and the close cell and aggregate proximity therein. A counterintuitive decrease in the mean aggregate size was apparent in the lower flow rate branches. This was attributed to the existence of regions depleted by aggregates of certain sizes in the parent branch, and to the change in the exact flow split location in the T-junction with flow ratio. The findings of the present investigation may have significant implications for microvascular flows and may help explain why the effects of physiological RBC aggregation are not deleterious in terms of in vivo vascular resistance.

  5. Cerebral blood flow tomography with xenon-133

    DEFF Research Database (Denmark)

    Lassen, N A

    1985-01-01

    computed tomograph (SPECT) is required. Two brain-dedicated SPECT systems designed for this purpose are mentioned, and the method is described with special reference to the limitations inherent in the soft energy of the 133Xe primary photons. CBF tomography can be used for a multitude of clinical...... of other tracers for CBF tomography using SPECT is summarized with emphasis on the 99mTc chelates that freely pass the intact blood-brain barrier. The highly sensitive brain-dedicated SPECT systems described are a prerequisite for achieving high resolution tomograms with such tracers....

  6. The effect of ventricular assist devices on cerebral blood flow and blood pressure fractality

    International Nuclear Information System (INIS)

    Bellapart, Judith; Fraser, John F; Chan, Gregory S H; Tzeng, Yu-Chieh; Ainslie, Philip N; Dunster, Kimble R; Barnett, Adrian G; Boots, Rob

    2011-01-01

    Biological signals often exhibit self-similar or fractal scaling characteristics which may reflect intrinsic adaptability to their underlying physiological system. This study analysed fractal dynamics of cerebral blood flow in patients supported with ventricular assist devices (VAD) to ascertain if sustained modifications of blood pressure waveform affect cerebral blood flow fractality. Simultaneous recordings of arterial blood pressure and cerebral blood flow velocity using transcranial Doppler were obtained from five cardiogenic shock patients supported by VAD, five matched control patients and five healthy subjects. Computation of a fractal scaling exponent (α) at the low-frequency time scale by detrended fluctuation analysis showed that cerebral blood flow velocity exhibited 1/f fractal scaling in both patient groups (α = 0.95 ± 0.09 and 0.97 ± 0.12, respectively) as well as in the healthy subjects (α = 0.86 ± 0.07). In contrast, fluctuation in blood pressure was similar to non-fractal white noise in both patient groups (α = 0.53 ± 0.11 and 0.52 ± 0.09, respectively) but exhibited 1/f scaling in the healthy subjects (α = 0.87 ± 0.04, P < 0.05 compared with the patient groups). The preservation of fractality in cerebral blood flow of VAD patients suggests that normal cardiac pulsation and central perfusion pressure changes are not the integral sources of cerebral blood flow fractality and that intrinsic vascular properties such as cerebral autoregulation may be involved. However, there is a clear difference in the fractal scaling properties of arterial blood pressure between the cardiogenic shock patients and the healthy subjects

  7. SPECT myocardial blood flow quantitation toward clinical use: a comparative study with {sup 13}N-Ammonia PET myocardial blood flow quantitation

    Energy Technology Data Exchange (ETDEWEB)

    Hsu, Bailing [University of Missouri-Columbia, Nuclear Science and Engineering Institute, Columbia, Missouri (United States); Hu, Lien-Hsin; Yang, Bang-Hung; Ting, Chien-Hsin; Huang, Wen-Sheng [Taipei Veterans General Hospital, Department of Nuclear Medicine, Taipei (China); Chen, Lung-Ching [Shin Kong Wu-Ho Su Memorial Hospital, Division of Cardiology, Taipei (China); Chen, Yen-Kung [Shin Kong Wu-Ho Su Memorial Hospital, Department of Nuclear Medicine, Taipei (China); Hung, Guang-Uei [Chang Bing Show Chwan Memorial Hospital, Department of Nuclear Medicine, Changhua (China); Wu, Tao-Cheng [National Yang-Ming University, Cardiovascular Research Center, Taipei (China)

    2017-01-15

    The aim of this study was to evaluate the accuracy of myocardial blood flow (MBF) quantitation of {sup 99m}Tc-Sestamibi (MIBI) single photon emission computed tomography (SPECT) compared with {sup 13}N-Ammonia (NH3) position emission tomography (PET) on the same cohorts. Recent advances of SPECT technologies have been applied to develop MBF quantitation as a promising tool to diagnose coronary artery disease (CAD) for areas where PET MBF quantitation is not available. However, whether the SPECT approach can achieve the same level of accuracy as the PET approach for clinical use still needs further investigations. Twelve healthy volunteers (HVT) and 16 clinical patients with CAD received both MIBI SPECT and NH3 PET flow scans. Dynamic SPECT images acquired with high temporary resolution were fully corrected for physical factors and processed to quantify K1 using the standard compartmental modeling. Human MIBI tracer extraction fraction (EF) was determined by comparing MIBI K1 and NH3 flow on the HVT group and then used to convert flow values from K1 for all subjects. MIBI and NH3 flow values were systematically compared to validate the SPECT approach. The human MIBI EF was determined as [1.0-0.816*exp(-0.267/MBF)]. Global and regional MBF and myocardial flow reserve (MFR) of MIBI SPECT and NH3 PET were highly correlated for all subjects (global R{sup 2}: MBF = 0.92, MFR = 0.78; regional R{sup 2}: MBF ≥ 0.88, MFR ≥ 0.71). No significant differences for rest flow, stress flow, and MFR between these two approaches were observed (All p ≥ 0.088). Bland-Altman plots overall revealed small bias between MIBI SPECT and NH3 PET (global: ΔMBF = -0.03Lml/min/g, ΔMFR = 0.07; regional: ΔMBF = -0.07 - 0.06, ΔMFR = -0.02 - 0.22). Quantitation with SPECT technologies can be accurate to measure myocardial blood flow as PET quantitation while comprehensive imaging factors of SPECT to derive the variability between these two approaches were fully addressed and corrected

  8. SPECT myocardial blood flow quantitation toward clinical use: a comparative study with "1"3N-Ammonia PET myocardial blood flow quantitation

    International Nuclear Information System (INIS)

    Hsu, Bailing; Hu, Lien-Hsin; Yang, Bang-Hung; Ting, Chien-Hsin; Huang, Wen-Sheng; Chen, Lung-Ching; Chen, Yen-Kung; Hung, Guang-Uei; Wu, Tao-Cheng

    2017-01-01

    The aim of this study was to evaluate the accuracy of myocardial blood flow (MBF) quantitation of "9"9"mTc-Sestamibi (MIBI) single photon emission computed tomography (SPECT) compared with "1"3N-Ammonia (NH3) position emission tomography (PET) on the same cohorts. Recent advances of SPECT technologies have been applied to develop MBF quantitation as a promising tool to diagnose coronary artery disease (CAD) for areas where PET MBF quantitation is not available. However, whether the SPECT approach can achieve the same level of accuracy as the PET approach for clinical use still needs further investigations. Twelve healthy volunteers (HVT) and 16 clinical patients with CAD received both MIBI SPECT and NH3 PET flow scans. Dynamic SPECT images acquired with high temporary resolution were fully corrected for physical factors and processed to quantify K1 using the standard compartmental modeling. Human MIBI tracer extraction fraction (EF) was determined by comparing MIBI K1 and NH3 flow on the HVT group and then used to convert flow values from K1 for all subjects. MIBI and NH3 flow values were systematically compared to validate the SPECT approach. The human MIBI EF was determined as [1.0-0.816*exp(-0.267/MBF)]. Global and regional MBF and myocardial flow reserve (MFR) of MIBI SPECT and NH3 PET were highly correlated for all subjects (global R"2: MBF = 0.92, MFR = 0.78; regional R"2: MBF ≥ 0.88, MFR ≥ 0.71). No significant differences for rest flow, stress flow, and MFR between these two approaches were observed (All p ≥ 0.088). Bland-Altman plots overall revealed small bias between MIBI SPECT and NH3 PET (global: ΔMBF = -0.03Lml/min/g, ΔMFR = 0.07; regional: ΔMBF = -0.07 - 0.06, ΔMFR = -0.02 - 0.22). Quantitation with SPECT technologies can be accurate to measure myocardial blood flow as PET quantitation while comprehensive imaging factors of SPECT to derive the variability between these two approaches were fully addressed and corrected. (orig.)

  9. Cine-CT measurement of cortical renal blood flow

    International Nuclear Information System (INIS)

    Jaschke, W.R.; Gould, R.G.; Cogan, M.G.; Sievers, R.; Lipton, M.J.

    1987-01-01

    A modified indicator-dilution technique using radiographic contrast material and a cine-CT scanner was used to measure blood flow in the renal cortex of dogs. To validate this technique, CT measurements were correlated with simultaneous measurements of flow determined by radioactive microspheres. Measurements were taken during euvolemic conditions and after hemorrhage. Thirty-nine measurements were compared, covering a flow range from 1 to 7 ml min-1 g-1, and a good correlation was found between the cine-CT and microsphere results (r = 0.93; p less than 0.001). Additionally, cine-CT measurements were made of the mean transit time (MTT) of contrast material through the renal cortex, and the reciprocal of these MTT values was also well correlated to microsphere determined flow (r = 0.94; p less than 0.001). Thus, cine-CT appears to be a promising new technique for measuring renal blood flow

  10. Study of Coronary Flow Reserve with Intravenous Use of Microbubbles (Contrast Echocardiography and Adenosine: Protocol for Clinical Application in Patients Suspected of Having Coronary Heart Disease

    Directory of Open Access Journals (Sweden)

    Morcerf Fernando

    2002-01-01

    Full Text Available OBJECTIVE: To test the feasibility, safety and accuracy of the adenosine protocol in the study of myocardial perfusion with microbubbles contrast echocardiography. METHODS: 81 pts (64 male, 60+11 years were submitted to contrast echocardiography with PESDA (sonicated solution of albumin 20%-1ml, dextrose 5%-12ml and deca-fluorobutane gas-8ml to study the myocardial perfusion at rest and after bolus injection of adenosine (6 to 18mg and to coronary angiography within 1 month each other. For each patient 3 left ventricle perfusion beds were considered (total of 243 territories. 208 territories were analyzed and 35 territories were excluded. PESDA was continuously infused (1-2ml/min, titrated for best myocardial contrast. Triggered (1:1 second harmonic imaging was used. RESULTS: Coronary angiography showed 70 flow limiting (> 75% lesions and 138 no flow limiting lesions. At rest an obvious myocardium contrast enhancement was seen in at least 1 segment of a territory in all patients. After adenosine injection an unquestionable further increase in myocardial contrast was observed in 136 territories (99% related to no flow limiting lesions, lasting < 10 s, and a myocardial perfusion defect was detected in 68 territories (97% related to flow limiting lesions. It was observed only 4 false results. There were no serious complications. CONCLUSION: Myocardial perfusion study with PESDA and adenosine protocol is a practical, safe and accurate method to analyze the coronary flow reserve.

  11. Predicting bifurcation angle effect on blood flow in the microvasculature.

    Science.gov (United States)

    Yang, Jiho; Pak, Y Eugene; Lee, Tae-Rin

    2016-11-01

    Since blood viscosity is a basic parameter for understanding hemodynamics in human physiology, great amount of research has been done in order to accurately predict this highly non-Newtonian flow property. However, previous works lacked in consideration of hemodynamic changes induced by heterogeneous vessel networks. In this paper, the effect of bifurcation on hemodynamics in a microvasculature is quantitatively predicted. The flow resistance in a single bifurcation microvessel was calculated by combining a new simple mathematical model with 3-dimensional flow simulation for varying bifurcation angles under physiological flow conditions. Interestingly, the results indicate that flow resistance induced by vessel bifurcation holds a constant value of approximately 0.44 over the whole single bifurcation model below diameter of 60μm regardless of geometric parameters including bifurcation angle. Flow solutions computed from this new model showed substantial decrement in flow velocity relative to other mathematical models, which do not include vessel bifurcation effects, while pressure remained the same. Furthermore, when applying the bifurcation angle effect to the entire microvascular network, the simulation results gave better agreements with recent in vivo experimental measurements. This finding suggests a new paradigm in microvascular blood flow properties, that vessel bifurcation itself, regardless of its angle, holds considerable influence on blood viscosity, and this phenomenon will help to develop new predictive tools in microvascular research. Copyright © 2016 Elsevier Inc. All rights reserved.

  12. Radionuclide study on hepatic blood flow in Schistosomiasis Japonica

    Energy Technology Data Exchange (ETDEWEB)

    Okada, Junichi; Uchiyama, Guio; Hayakawa, Kazushige; Hayashi, Sanshin; Araki, Tsutomu; Arai, Takao; Iuchi, Masahiko

    1986-11-01

    Schistosomiasis Japonica is a regional disease found in elderly people who were living in once-endemic areas in Japan. Yamanashi was one of these areas until 1970, since when no newly infected patients were reported. The disease is characteristic of developing irreversible interstitial fibrosis of the liver, where parasites migrate and lay eggs. Portal hypertension, esophageal varices and hepatocellular carcinomas are the common features of the results. In order to estimate patient's hepatic blood flow, radionuclide angiography of the liver with the use of 10 - 15 millicuries of Tc-99m phytate were performed prior to the conventional multiview imaging. Twenty-two patients with schistosomiasis and twelve adults without evidence of liver disease were studied. A time-activity curve of the right lobe of the liver was generated by a computer, and the ratio of arterial blood flow to portal blood flow was calculated. As a result, a good correlation was found between the arterial to portal blood flow ratio and the grade of hepatic fibrosis verified by laparoscopic biopsy. The development of esophageal varices were likely to correlate well with the blood flow ratio rather than scores on the conventional static liver and spleen scintigram. The study was useful for evaluating patient's clinical stages and prognosis.

  13. Sex differences of human cortical blood flow and energy metabolism.

    Science.gov (United States)

    Aanerud, Joel; Borghammer, Per; Rodell, Anders; Jónsdottir, Kristjana Y; Gjedde, Albert

    2017-07-01

    Brain energy metabolism is held to reflect energy demanding processes in neuropil related to the density and activity of synapses. There is recent evidence that men have higher density of synapses in temporal cortex than women. One consequence of these differences would be different rates of cortical energy turnover and blood flow in men and women. To test the hypotheses that rates of oxygen consumption (CMRO 2 ) and cerebral blood flow are higher in men than in women in regions of cerebral cortex, and that the differences persist with aging, we used positron emission tomography to determine cerebral blood flow and cerebral metabolic rate of oxygen as functions of age in healthy volunteers of both sexes. Cerebral metabolic rate of oxygen did not change with age for either sex and there were no differences of mean values of cerebral metabolic rate of oxygen between men and women in cerebral cortex. Women had significant decreases of cerebral blood flow as function of age in frontal and parietal lobes. Young women had significantly higher cerebral blood flow than men in frontal and temporal lobes, but these differences had disappeared at age 65. The absent sex difference of cerebral energy turnover suggests that the known differences of synaptic density between the sexes are counteracted by opposite differences of individual synaptic activity.

  14. Radionuclide study on hepatic blood flow in Schistosomiasis Japonica

    International Nuclear Information System (INIS)

    Okada, Junichi; Uchiyama, Guio; Hayakawa, Kazushige; Hayashi, Sanshin; Araki, Tsutomu; Arai, Takao; Iuchi, Masahiko.

    1986-01-01

    Schistosomiasis Japonica is a regional disease found in elderly people who were living in once-endemic areas in Japan. Yamanashi was one of these areas until 1970, since when no newly infected patients were reported. The disease is characteristic of developing irreversible interstitial fibrosis of the liver, where parasites migrate and lay eggs. Portal hypertension, esophageal varices and hepatocellular carcinomas are the common features of the results. In order to estimate patient's hepatic blood flow, radionuclide angiography of the liver with the use of 10 - 15 millicuries of Tc-99m phytate were performed prior to the conventional multiview imaging. Twenty-two patients with schistosomiasis and twelve adults without evidence of liver disease were studied. A time-activity curve of the right lobe of the liver was generated by a computer, and the ratio of arterial blood flow to portal blood flow was calculated. As a result, a good correlation was found between the arterial to portal blood flow ratio and the grade of hepatic fibrosis verified by laparoscopic biopsy. The development of esophageal varices were likely to correlate well with the blood flow ratio rather than scores on the conventional static liver and spleen scintigram. The study was useful for evaluating patient's clinical stages and prognosis. (author)

  15. The influence of transcutaneous electrical neurostimulation (TENS) on human cerebral blood flow velocities

    NARCIS (Netherlands)

    ter Laan, Mark; van Dijk, J. Marc C.; Elting, Jan-Willem J.; Fidler, Vaclav; Staal, Michiel J.

    It has been shown that transcutaneous electrical neurostimulation (TENS) reduces sympathetic tone. Spinal cord stimulation (SCS) has proven qualities to improve coronary, peripheral, and cerebral blood circulation. Therefore, we postulate that TENS and SCS affect the autonomic nervous system in

  16. Impact of extracorporeal blood flow rate on blood pressure, pulse rate and cardiac output during haemodialysis

    DEFF Research Database (Denmark)

    Schytz, Philip Andreas; Mace, Maria Lerche; Soja, Anne Merete Boas

    2015-01-01

    BACKGROUND: If blood pressure (BP) falls during haemodialysis (HD) [intradialytic hypotension (IDH)] a common clinical practice is to reduce the extracorporeal blood flow rate (EBFR). Consequently the efficacy of the HD (Kt/V) is reduced. However, only very limited knowledge on the effect...

  17. Intraoperative coronary grafts flow measurement using the TTFM flowmeter: results from a domestic sample.

    Science.gov (United States)

    Succi, José Ernesto; Gerola, Luis Roberto; Succi, Guilherme de Menezes; Kim, Hyong Chun; Paredes, Jorge Edwin Morocho; Bufollo, Enio

    2012-01-01

    To evaluate intraoperative graft patency and identify grafts under risk of early occlusion. Fifty four patients were submitted to coronary artery bypass surgery and the graft flow was assessed by the Flowmeter (Medtronic Medistim), which utilizes the TTFM method. Three patients had left main disease and 48 had normal or mildly reduced left ventricular function. In hospital mortality was 3.7% (two patients), one for mesenteric thrombosis and one due to cardiogenic chock. Seventeen patients (34%) were submitted to off pump CABG. Arterial Graft flow measures ranged from 8 to 106 ml/min (average 31.14 ml/min), and venous grafts flow ranged from 9 to 149 ml/min (average 50.42 ml/min). Flowmeter use represents higher safety both for patients and surgeons. Even under legal aspects, the documentation provided by the device can avoid future questionings.

  18. Quantification of cerebral blood flow via Duplex sonography

    International Nuclear Information System (INIS)

    Vogl, G.; Pohl, P.; Willeit, J.; Aichner, F.

    1987-01-01

    An attempt was made to measure quantitatively the total cerebral blood flow by means of Duplex sonography. In a group of healthy young subjects a median value for total cerebral blood flow was obtained amounting to 469 ml/min ± 30%, repeat measurements yielded a maximum deviation of ± 11%. In three patients the values obtained after severe apoplectic insult due to occlusion of the internal carotid artery were definitely below the value of the group of healthy subjects, whereas the value for the total blood flow was in the upper range of normal values in a patient with occlusion of the a. cerebri media. Comparative measurements of the regional cerebral blood flow with xenon 13 yielded in those patients with occlusion of the internal carotid artery a markedly reduced mean flow and in the patient with occlusion of the a. cerebri media a less markedly reduced mean flow. Regionally reduced perfusion was seen in all the four patients in the range of the clinically and computer tomographically well-known ischaemia zone. Thanks to the simplicity of this sonographic examination method it could be a useful decision parameter in determining the indication for a reconstruction of the carotid artery, especially in asymptotic patients. (orig.) [de

  19. Measurement of regional hepatic blood flow by scintiphotosplenoportography

    Energy Technology Data Exchange (ETDEWEB)

    Kashiwagi, T; Kimura, K; Kamada, T; Abe, H [Osaka Univ. (Japan). Dept. of Radiology and Nuclear Medicine

    1978-08-01

    A new technique for estimating regional hepatic blood flow using the inert gas washout technique and scintillation camera following injection of /sup 133/Xe into the spleen is presented. This technique is easily, rapidly and repeatedly performed and permits the measurement of nutrient hepatic tissue blood flow. Measurement of regional hepatic blood flow in right and/or left lobes was performed in 28 patients. In all but one patient the right lobar flow value was equal to or greater than the left one. The right lobar flow was 86.20 +- 12.83 ml/100 gm/min in 3 patients without liver disease, 75.12 +- 14.54 ml/100 gm/min in 12 with chronic hepatitis and 51.24 +- 17.13 ml/100 gm/min in 11 with liver cirrhosis. This result suggests that hepatic tissue blood flow is significantly decreased in patients with liver cirrhosis. Scintillation camera images of initial xenon distribution in combination with monitor of washout curves over the liver also provide more information on the presence of extra- and intrahepatic shunts. Therefore, this technique appears to be clinically useful in evaluation of hemodynamic phenomena associated with liver diseases.

  20. 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.

  1. Neuromodulation therapy does not influence blood flow distribution or left-ventricular dynamics during acute myocardial ischemia.

    Science.gov (United States)

    Kingma, J G; Linderoth, B; Ardell, J L; Armour, J A; DeJongste, M J; Foreman, R D

    2001-08-13

    Electrical stimulation of the dorsal aspect of the upper thoracic spinal cord is used increasingly to treat patients with angina pectoris refractory to conventional therapeutic strategies. The purpose of this study was to determine whether spinal cord stimulation (SCS) in dogs affects regional myocardial blood flow and left-ventricular (LV) function before and during transient obstruction of the left anterior descending coronary artery (LAD). In anesthetized dogs, regional myocardial blood flow distribution was determined using radiolabeled microspheres and left-ventricular function was measured by impedance-derived pressure-volume loops. SCS was accomplished by stimulating the dorsal T1-T2 segments of the spinal cord using epidural bipolar electrodes at 90% of motor threshold (MT) (50 Hz, 0.2-ms duration). Effects of 5-min SCS were assessed under basal conditions and during 4-min occlusion of the LAD. SCS alone evoked no change in regional myocardial blood flow or cardiovascular indices. Transient LAD occlusion significantly diminished blood flow within ischemic, but not in non-ischemic myocardial tissue. Left ventricular pressure-volume loops were shifted rightward during LAD occlusion. Cardiac indices were altered similarly during LAD occlusion and concurrent SCS. SCS does not influence the distribution of blood flow within the non-ischemic or ischemic myocardium. Nor does it modify LV pressure-volume dynamics in the anesthetized experimental preparation.

  2. Assessing regional cerebral blood flow in depression using 320-slice computed tomography.

    Directory of Open Access Journals (Sweden)

    Yiming Wang

    Full Text Available While there is evidence that the development and course of major depressive disorder (MDD symptomatology is associated with vascular disease, and that there are changes in energy utilization in the disorder, the extent to which cerebral blood flow is changed in this condition is not clear. This study utilized a novel imaging technique previously used in coronary and stroke patients, 320-slice Computed-Tomography (CT, to assess regional cerebral blood flow (rCBF in those with MDD and examine the pattern of regional cerebral perfusion. Thirty nine participants with depressive symptoms (Hamilton Depression Rating Scale 24 (HAMD24 score > 20, and Self-Rating Depression Scale (SDS score > 53 and 41 healthy volunteers were studied. For all subjects, 3 ml of venous blood was collected to assess hematological parameters. Transcranial Doppler (TCD ultrasound was utilized to measure parameters of cerebral artery rCBFV and analyse the Pulsatility Index (PI. 16 subjects (8 =  MDD; 8 =  healthy also had rCBF measured in different cerebral artery regions using 320-slice CT. Differences among groups were analyzed using ANOVA and Pearson's tests were employed in our statistical analyses. Compared with the control group, whole blood viscosity (including high\\middle\\low shear rateand hematocrit (HCT were significantly increased in the MDD group. PI values in different cerebral artery regions and parameters of rCBFV in the cerebral arteries were decreased in depressive participants, and there was a positive relationship between rCBFV and the corresponding vascular rCBF in both gray and white matter. rCBF of the left gray matter was lower than that of the right in MDD. Major depression is characterized by a wide range of CBF impairments and prominent changes in gray matter blood flow. 320-slice CT appears to be a valid and promising tool for measuring rCBF, and could thus be employed in psychiatric settings for biomarker and treatment response purposes.

  3. Mini-cardiopulmonary bypass impact on blood conservation strategy in coronary artery bypass grafting.

    Science.gov (United States)

    Abdel Aal, Mohamed; ElNahal, Nezar; Bakir, Bakir Moustafa; Fouda, Mohamed

    2011-04-01

    Cardiopulmonary bypass (CPB) using a closed circuit system with minimal priming volume can be a solution to ameliorate adverse effects of CPB. We hypothesize that the use of mini-bypass in routine coronary artery bypass grafting (CABG) reduces homologous blood product use and postoperative bleeding. The study is designed to determine the differences in blood loss and transfusion requirements associated with a minimized CPB circuit vs. a standard bypass circuit. From February 2009 to August 2009, 80 patients were prospectively randomized to undergo elective CABG. Group A included 40 patients who had the minimized bypass circuit (Medtronic Resting Heart Circuit). Group B had an equal number of patients who had the standard CPB circuit (Stockert III, SEC.BM). Laboratory parameters for hemoglobin, hematocrit and platelet count were measured at baseline after initiation of CPB and after bypass. Blood usage was controlled by study-specific protocol (transfusion for hemoglobin platelets (1.95±2.95 units vs. 3.23±2.85), and postoperative drainage in 24 hours (531.62±220.12 ml vs. 729±294.9 ml, P<0.05). The hematocrit was 33±5% in group A, and 27±1% in group B. There was statistical differences seen in the mean hemoglobin level which was 10.19±0.65 g/dl in group A, and 9.4±0.68 g/dl in group B. There was statistical difference in the duration of ventilation, length of ICU stay. The requirement of inotropic support was lower in group A. The adoption of mini-bypass significantly reduces morbidity including donor blood usage and postoperative bleeding in routine CABG patients.

  4. ART-ML - a novel XML format for the biological procedures modeling and the representation of blood flow simulation.

    Science.gov (United States)

    Karvounis, E C; Tsakanikas, V D; Fotiou, E; Fotiadis, D I

    2010-01-01

    The paper proposes a novel Extensible Markup Language (XML) based format called ART-ML that aims at supporting the interoperability and the reuse of models of blood flow, mass transport and plaque formation, exported by ARTool. ARTool is a platform for the automatic processing of various image modalities of coronary and carotid arteries. The images and their content are fused to develop morphological models of the arteries in easy to handle 3D representations. The platform incorporates efficient algorithms which are able to perform blood flow simulation. In addition atherosclerotic plaque development is estimated taking into account morphological, flow and genetic factors. ART-ML provides a XML format that enables the representation and management of embedded models within the ARTool platform and the storage and interchange of well-defined information. This approach influences in the model creation, model exchange, model reuse and result evaluation.

  5. Regulation of the skeletal muscle blood flow in humans

    DEFF Research Database (Denmark)

    Mortensen, Stefan; Saltin, Bengt

    2014-01-01

    In humans, skeletal muscle blood flow is regulated by an interaction between several locally formed vasodilators including nitric oxide (NO) and prostaglandins. In plasma, ATP is a potent vasodilator that stimulates the formation of NO and prostaglandins and very importantly can offset local...... concentration does not increase during exercise. In the skeletal muscle interstitium, there is a marked increase in the concentration of ATP and adenosine and this increase is tightly coupled to the increase in blood flow. The sources of interstitial ATP and adenosine are thought to be skeletal muscle cells...... hyperaemia whereas the role of ATP remains uncertain due to lack of specific purinergic receptor blockers for human use. The purpose of this review is to address the interaction between vasodilator systems and to discuss the multiple proposed roles of ATP in human skeletal muscle blood flow regulation...

  6. A dynamic model of renal blood flow autoregulation

    DEFF Research Database (Denmark)

    Holstein-Rathlou, N H; Marsh, D J

    1994-01-01

    To test whether a mathematical model combining dynamic models of the tubuloglomerular feedback (TGF) mechanism and the myogenic mechanism was sufficient to explain dynamic autoregulation of renal blood flow, we compared model simulations with experimental data. To assess the dynamic characteristics...... of renal autoregulation, a broad band perturbation of the arterial pressure was employed in both the simulations and the experiments. Renal blood flow and tubular pressure were used as response variables in the comparison. To better approximate the situation in vivo where a large number of individual...... data, which shows a unimodal curve for the admittance phase. The ability of the model to reproduce the experimental data supports the hypothesis that dynamic autoregulation of renal blood flow is due to the combined action of TGF and the myogenic response....

  7. Noninvasive measurement of blood flow and extraction fraction

    Energy Technology Data Exchange (ETDEWEB)

    Peters, A.M.; Gunasekera, R.D.; Henderson, B.L.; Brown, J.; Lavender, J.P.; De Souza, M.; Ash, J.M.; Gilday, D.L.

    1987-10-01

    We describe the theory of a technique for the noninvasive measurement of organ blood flow which is based on the principle of fractionation of cardiac output and is applicable with any recirculating gamma emitting tracer. The technique effectively determines the count rate that would be recorded over the organ if the tracer behaved like radiolabelled microspheres and was completely trapped in the organ's vascular bed on first pass. After correction for organ depth, the estimated first pass activity plateau, expressed as a fraction of the injected dose is equal to the organ's fraction of the cardiac output (CO). By extending the theory, organ extraction fraction of extractable tracers or mean transit time of nonextractable tracers can be measured. The technique was applied to the measurement of renal blood flow in the native and transplanted kidney, splenic blood flow, the extraction fraction of DTPA by the kidney and of sulphur colloid by the spleen.

  8. Renal transplantant blood flow in patients with acute tubular necrosis

    Energy Technology Data Exchange (ETDEWEB)

    Huic, D; Crnkovic, S; Bubic-Filipi, L J; Grosev, D; Dodig, P; Porapat, M; Puretic, Z [Univ. Hospital Rebro, Zagreb (Croatia)

    1997-09-01

    The aim of this study was to investigate the quantity of renal transport blood flow in patients affected by acute tubular necrosis (ATN). During the four years period two hundred and thirty-three studies were performed using {sup 99m}Tc pertechnetate and {sup 131}I - OIH. Renal blood flow was calculated from the first-pass time activity curves generated over the kidney and aorta and expressed as a percentage of cardiac output (RBF/CO). Renal transplant blood flow is clearly diminished in ATN, similar as in acute rejection, and significantly related to the graft function, what means that RBF/CO value could potentially serve as a prognostic factor in the graft function recovery from ATN.

  9. Noninvasive measurement of blood flow and extraction fraction

    International Nuclear Information System (INIS)

    Peters, A.M.; Gunasekera, R.D.; Henderson, B.L.; Brown, J.; Lavender, J.P.; De Souza, M.; Ash, J.M.; Gilday, D.L.

    1987-01-01

    We describe the theory of a technique for the noninvasive measurement of organ blood flow which is based on the principle of fractionation of cardiac output and is applicable with any recirculating gamma emitting tracer. The technique effectively determines the count rate that would be recorded over the organ if the tracer behaved like radiolabelled microspheres and was completely trapped in the organ's vascular bed on first pass. After correction for organ depth, the estimated first pass activity plateau, expressed as a fraction of the injected dose is equal to the organ's fraction of the cardiac output (CO). By extending the theory, organ extraction fraction of extractable tracers or mean transit time of nonextractable tracers can be measured. The technique was applied to the measurement of renal blood flow in the native and transplanted kidney, splenic blood flow, the extraction fraction of DTPA by the kidney and of sulphur colloid by the spleen. (author)

  10. Reduced blood flow to contracting skeletal muscle in ageing humans

    DEFF Research Database (Denmark)

    Nyberg, Michael Permin; Hellsten, Ylva

    2016-01-01

    The ability to sustain a given absolute submaximal workload declines with advancing age likely due to a lower level of blood flow and O2 delivery to the exercising muscles. Given that physical inactivity mimics many of the physiological changes associated with ageing, separating the physiological...... consequences of ageing and physical inactivity can be challenging; yet, observations from cross-sectional and longitudinal studies on the effects of physical activity have provided some insight. Physical activity has the potential to offset the age-related decline in blood flow to contracting skeletal muscle...... the O2 demand of the active skeletal muscle of aged individuals during conditions where systemic blood flow is not limited by cardiac output seems to a large extent to be related to the level of physical activity. This article is protected by copyright. All rights reserved....

  11. A numerical study of blood flow using mixture theory.

    Science.gov (United States)

    Wu, Wei-Tao; Aubry, Nadine; Massoudi, Mehrdad; Kim, Jeongho; Antaki, James F

    2014-03-01

    In this paper, we consider the two dimensional flow of blood in a rectangular microfluidic channel. We use Mixture Theory to treat this problem as a two-component system: One component is the red blood cells (RBCs) modeled as a generalized Reiner-Rivlin type fluid, which considers the effects of volume fraction (hematocrit) and influence of shear rate upon viscosity. The other component, plasma, is assumed to behave as a linear viscous fluid. A CFD solver based on OpenFOAM ® was developed and employed to simulate a specific problem, namely blood flow in a two dimensional micro-channel, is studied. Finally to better understand this two-component flow system and the effects of the different parameters, the equations are made dimensionless and a parametric study is performed.

  12. Sex differences of human cortical blood flow and energy metabolism

    DEFF Research Database (Denmark)

    Aanerud, Joel; Borghammer, Per; Rodell, Anders

    2017-01-01

    cerebral blood flow and cerebral metabolic rate of oxygen as functions of age in healthy volunteers of both sexes. Cerebral metabolic rate of oxygen did not change with age for either sex and there were no differences of mean values of cerebral metabolic rate of oxygen between men and women in cerebral...... cortex. Women had significant decreases of cerebral blood flow as function of age in frontal and parietal lobes. Young women had significantly higher cerebral blood flow than men in frontal and temporal lobes, but these differences had disappeared at age 65. The absent sex difference of cerebral energy...... turnover suggests that the known differences of synaptic density between the sexes are counteracted by opposite differences of individual synaptic activity....

  13. Resting Pd/Pa and haemodynamic relevance of coronary stenosis as evaluated by fractional flow reserve.

    Science.gov (United States)

    De Luca, Giuseppe; Verdoia, Monica; Barbieri, Lucia; Marino, Paolo; Suryapranata, Harry

    2018-03-01

    Fractional flow reserve (FFR) currently represents the gold standard in the evaluation of the haemodynamic relevance of coronary stenoses. However, both intracoronary and intravenous adenosine may be tolerated poorly by some patients. Therefore, considerable interest had been focused in the last few years on new adenosine-free indexes to define the haemodynamic relevance of coronary stenoses. So far, few data have been reported on resting Pd/Pa and its correlation with FFR as evaluated with high-dose intracoronary adenosine administration, which is the aim of the current study. FFR was assessed in 120 patients with 137 intermediate lesions during cardiac catheterization by a pressure-recording guidewire (PrimeWire). FFR was calculated as the ratio of the distal coronary pressure to the aortic pressure at hyperaemia. Intracoronary doses of adenosine were administered up to 720 μg as intracoronary boli. Exclusion criteria were as follows: (a) allergy to adenosine; (b) baseline bradycardia (heart rate values and increased the percentage of patients showing an FFR less than 0.80. Resting Pd/Pa showed good accuracy in the identification of patients with significant FFR values (value in the prediction of a positive FFR value. A value up to 0.88 was associated with a 100% positive predictive value, whereas a value of at least 0.95 was associated with a 95% negative predictive value. This study showed that in intermediate lesions, resting Pd/Pa was related linearly to FFR. We identified 0.93 as the best cut-off value in the prediction of haemodynamically significant coronary stenosis as evaluated by FFR. However, cut-off values of 0.88 and 0.95 could provide the maximal predictive positive and negative values, suggesting the additional use of FFR only in patients with resting values within this range.

  14. A machine-learning approach for computation of fractional flow reserve from coronary computed tomography.

    Science.gov (United States)

    Itu, Lucian; Rapaka, Saikiran; Passerini, Tiziano; Georgescu, Bogdan; Schwemmer, Chris; Schoebinger, Max; Flohr, Thomas; Sharma, Puneet; Comaniciu, Dorin

    2016-07-01

    Fractional flow reserve (FFR) is a functional index quantifying the severity of coronary artery lesions and is clinically obtained using an invasive, catheter-based measurement. Recently, physics-based models have shown great promise in being able to noninvasively estimate FFR from patient-specific anatomical information, e.g., obtained from computed tomography scans of the heart and the coronary arteries. However, these models have high computational demand, limiting their clinical adoption. In this paper, we present a machine-learning-based model for predicting FFR as an alternative to physics-based approaches. The model is trained on a large database of synthetically generated coronary anatomies, where the target values are computed using the physics-based model. The trained model predicts FFR at each point along the centerline of the coronary tree, and its performance was assessed by comparing the predictions against physics-based computations and against invasively measured FFR for 87 patients and 125 lesions in total. Correlation between machine-learning and physics-based predictions was excellent (0.9994, P machine-learning algorithm with a sensitivity of 81.6%, a specificity of 83.9%, and an accuracy of 83.2%. The correlation was 0.729 (P assessment of FFR. Average execution time went down from 196.3 ± 78.5 s for the CFD model to ∼2.4 ± 0.44 s for the machine-learning model on a workstation with 3.4-GHz Intel i7 8-core processor. Copyright © 2016 the American Physiological Society.

  15. Radiolabeled microsphere measurements of alveolar bone blood flow in dogs

    International Nuclear Information System (INIS)

    Kaplan, M.L.; Jeffcoat, M.K.; Goldhaber, P.

    1978-01-01

    Radiolabeled microspheres were injected into the left cardiac ventricle in healthy adult dogs to quantify blood in maxillary and mandibular alveolar bone. Heart rate, arterial blood pressure and pulse contour were monitored throughout each experiment. Blood flow in maxillary alveolar bone was more than 30 % greater (p<.001) than in mandibular alveolar bone. Alveolar bone blood flow (mean +- S.D.) measured as ml/min per gram was 0.12 +- .02 in the maxilla compared to 0.09 +- .02 in the mandible. The cardiovascular parameters monitored were constant immediately prior to the injection of microspheres and remained unchanged during and following injection. It is possible that radiolabeled microspheres can be used to quantify the circulatory changes in alveolar bone during the development of destructive periodontal disease in dogs. (author)

  16. Evaluation of Tp-Te Interval and Tp-Te/QT Ratio in Patients with Coronary Slow Flow Tp-Te/QT Ratio and Coronary Slow Flow.

    Science.gov (United States)

    Tenekecioglu, Erhan; Karaagac, Kemal; Yontar, Osman Can; Agca, Fahriye Vatansever; Ozluk, Ozlem Arican; Tutuncu, Ahmet; Arslan, Burhan; Yilmaz, Mustafa

    2015-06-01

    Coronary slow flow (CSF) phenomenon is described by angiographically normal coronary arteries with delayed opacification of the distal vasculature. Several studies have suggested that the interval from the peak to the end of the electrocardiographic T wave (Tp-Te) may correspond to the transmural dispersion of the repolarization and that increased Tp-Te interval and Tp-Te/QT ratio are associated with malignant ventricular arrhythmias. The aim of this study was to evaluate the ventricular repolarization by using Tp-Te interval and Tp-Te/QT ratio in patients with CSF. This study included 50 CSF patients (40 male, mean age 48.6±12.5 years) and 40 control individuals (23 male, mean age 47.8±12.5 years). Tp-Te interval and Tp-Te/QT ratio were measured from the 12-lead electrocardiogram. These parameters were compared in groups. Baseline characteristics of the study groups were comparable. In electrocardiographic parameters analysis, QT and corrected QT were similar in CSF patients compared to the controls (357±35.2 vs 362±38.0 milliseconds and 419±25.8 vs 430±44.2 milliseconds, all p value >0.05). Tp-Te interval, Tp-Te/QT and Tp-Te/QTc ratio were significantly higher in CSF patients (85±13.7 vs 74±9.9 milliseconds and 0.24±0.03 vs 0.20±0.02 and 0.20±0.03 vs 0.17±0.02 all p value ratio are prolonged in patients with CSF.

  17. Effect of pregnancy on regional cerebral blood flow

    International Nuclear Information System (INIS)

    Nagamachi, Shigeki; Hoshi, Hiroaki; Jinnouchi, Seishi; Ohnishi, Takashi; Futami, Shigemi; Watanabe, Katsushi; Ikeda, Tomoaki; Mori, Norimasa

    1993-01-01

    Regional cerebral blood flow (r-CBF) of 10 pregnant women were quantified by 133 Xe SPECT study with inhalation method before and after artificial abortion. During pregnancy, value of r-CBF in each region except occipital lobe was significantly higher than that of the post abortion. Arterial blood gas was analyzed after SPECT procedure. P co2 concentration increased significantly after artificial abortion. Although its mechanism is unknown, our preliminary work demonstrates that r-CBF increased by pregnancy. (author)

  18. Numerical simulation of human blood flow in microvessels

    International Nuclear Information System (INIS)

    Attaullah; Chughtai, I.R.; Nadeem, M.

    2009-01-01

    In this research, steady state flow of human blood in vascular system has been studied. Computational fluid dynamics has been used to predict pressure drop in human arteriole, artery, capillary, venule and vein. Viscosity of human blood has been treated in different ways by employing Newtonian, Power law and Herschel-Bulkley models. It has been observed that the Herschel-Bulkley model predicts the pressure gradients in all diameters reasonably whereas Newtonian and Power laws have their limitations. (author)

  19. Renal blood flow and oxygenation drive nephron progenitor differentiation.

    Science.gov (United States)

    Rymer, Christopher; Paredes, Jose; Halt, Kimmo; Schaefer, Caitlin; Wiersch, John; Zhang, Guangfeng; Potoka, Douglas; Vainio, Seppo; Gittes, George K; Bates, Carlton M; Sims-Lucas, Sunder

    2014-08-01

    During kidney development, the vasculature develops via both angiogenesis (branching from major vessels) and vasculogenesis (de novo vessel formation). The formation and perfusion of renal blood vessels are vastly understudied. In the present study, we investigated the regulatory role of renal blood flow and O2 concentration on nephron progenitor differentiation during ontogeny. To elucidate the presence of blood flow, ultrasound-guided intracardiac microinjection was performed, and FITC-tagged tomato lectin was perfused through the embryo. Kidneys were costained for the vasculature, ureteric epithelium, nephron progenitors, and nephron structures. We also analyzed nephron differentiation in normoxia compared with hypoxia. At embryonic day 13.5 (E13.5), the major vascular branches were perfused; however, smaller-caliber peripheral vessels remained unperfused. By E15.5, peripheral vessels started to be perfused as well as glomeruli. While the interior kidney vessels were perfused, the peripheral vessels (nephrogenic zone) remained unperfused. Directly adjacent and internal to the nephrogenic zone, we found differentiated nephron structures surrounded and infiltrated by perfused vessels. Furthermore, we determined that at low O2 concentration, little nephron progenitor differentiation was observed; at higher O2 concentrations, more differentiation of the nephron progenitors was induced. The formation of the developing renal vessels occurs before the onset of blood flow. Furthermore, renal blood flow and oxygenation are critical for nephron progenitor differentiation. Copyright © 2014 the American Physiological Society.

  20. Relationship between insulin resistance and tissue blood flow in preeclampsia.

    Science.gov (United States)

    Anim-Nyame, Nick; Gamble, John; Sooranna, Suren R; Johnson, Mark R; Steer, Philip J

    2015-05-01

    Preeclampsia is characterized by generalized endothelial dysfunction and impaired maternal tissue perfusion, and insulin resistance is a prominent feature of this disease. The aim of this study was to test the hypothesis that insulin resistance in preeclampsia is related to the reduced resting tissue blood flow. We used venous occlusion plethysmography to compare the resting calf muscle blood flow (measured as QaU) in 20 nulliparous women with preeclampsia and 20 normal pregnant controls matched for maternal age, gestational age, parity and BMI during the third trimester. Fasting blood samples were obtained to measure the plasma concentrations of insulin and glucose, and to calculate the fasting insulin resistance index (FIRI), a measure of insulin resistance in both groups of women. Calf blood flow was significantly reduced in the preeclampsia group (1.93 ± 0.86 QaU), compared with normal pregnant controls (3.94 ± 1.1 QaU, P insulin concentrations and Insulin Resistance Index were significantly higher in preeclampsia compared with normal pregnancy (P insulin concentrations (r = -0.57, P = 0.008) and FIRI (r = -0.59, P = 0.006) in preeclampsia, but not in normal pregnancy. These findings support our hypothesis and raise the possibility that reduced tissue blood flow may a play a role in the increased insulin resistance seen in preeclampsia.

  1. Follicle vascularity coordinates corpus luteum blood flow and progesterone production.

    Science.gov (United States)

    de Tarso, S G S; Gastal, G D A; Bashir, S T; Gastal, M O; Apgar, G A; Gastal, E L

    2017-03-01

    Colour Doppler ultrasonography was used to compare the ability of preovulatory follicle (POF) blood flow and its dimensions to predict the size, blood flow and progesterone production capability of the subsequent corpus luteum (CL). Cows (n=30) were submitted to a synchronisation protocol. Follicles ≥7mm were measured and follicular wall blood flow evaluated every 12h for approximately 3.5 days until ovulation. After ovulation, cows were scanned daily for 8 days and similar parameters were evaluated for the CL. Blood samples were collected and plasma progesterone concentrations quantified. All parameters were positively correlated. Correlation values ranged from 0.26 to 0.74 on data normalised to ovulation and from 0.31 to 0.74 on data normalised to maximum values. Correlations between calculated ratios of both POF and CL in data normalised to ovulation and to maximum values ranged from moderate (0.57) to strong (0.87). Significant (Pprogesterone concentrations of the resultant CL. These findings indicate that follicle vascularity coordinates CL blood flow and progesterone production in synchronised beef cows.

  2. Uteroplacental blood flow during alkalosis in the sheep

    International Nuclear Information System (INIS)

    Buss, D.D.; Bisgard, G.E.; Rawlings, C.A.; Rankin, J.H.G.

    1975-01-01

    Uteroplacental blood flow was measured by the radioactive-microsphere technique in eight near-term pregnant ewes during a normal control period and during maternal metabolic alkalosis. All measurements were made on awake, unanesthetized animals. Alkalosis, defined for this study as an arterial pH of 7.60 or greater, was produced by the oral administration of sodium bicarbonate, 3 g/kg body wt. The rise in pH thus produced was unaccompanied by significant changes in systemic arterial blood pressure and cardiac output, while maternal arterial P/sub CO 2 / rose slightly from control levels. Cotyledonary blood flow declined from a control value of 1.177 ml/min to 1.025 ml/min during alkalosis. This decline of 13 percent in cotyledonary blood flow is significant (P less than 0.02). Blood flow to the remaining uterine tissue, or noncotyledonary uterus, did not change with alkalosis, being maintained at approximately 195 ml/min. It is concluded that maternal alkalosis, unaccompanied by major changes in P /sub CO 2 / and systemic arterial pressure, causes a small increase in the resistance of the uteroplacental circulation

  3. Inner ocular blood flow responses to an acute decrease in blood pressure in resting humans

    International Nuclear Information System (INIS)

    Ikemura, Tsukasa; Kashima, Hideaki; Yamaguchi, Yuji; Miyaji, Akane; Hayashi, Naoyuki

    2015-01-01

    Whether inner ocular vessels have an autoregulatory response to acute fluctuations in blood pressure is unclear. We tried to examine the validity of acute hypotension elicited by thigh-cuff release as to assess the dynamic autoregulation in the ocular circulation. Blood flow velocity in the superior nasal and inferior temporal retinal arterioles, and in the retinal and choroidal vasculature were measured with the aid of laser speckle flowgraphy before and immediately after an acute decrease in blood pressure in 20 healthy subjects. Acute hypotension was induced by a rapid release of bilateral thigh occlusion cuffs that had been inflated to 220 mmHg for 2 min. The ratio of the relative change in retinal and choroidal blood flow velocity to the relative change in mean arterial blood pressure (MAP) was calculated. Immediately after cuff release, the MAP and blood flows in the all ocular target vessels decreased significantly from the baseline values obtained before thigh-cuff release. The ratio of the relative change in inner ocular blood flow velocity to that in the MAP exceeded 1% / %mmHg. An explicit dynamic autoregulation in inner ocular vessels cannot be demonstrated in response to an acute hypotension induced by the thigh-cuff release technique. (paper)

  4. Influence of myocardial oxygen demand on the coronary vascular response to arterial blood gas changes in humans.

    Science.gov (United States)

    Vermeulen, Tyler Dennis; Boulet, Lindsey M; Stembridge, Mike; Williams, Alexandra Mackenzie; Anholm, James D; Subedi, Prajan; Gasho, Chris; Ainslie, Philip N; Feigl, Eric O; Foster, Glen Edward

    2018-03-30

    It remains unclear if the human coronary vasculature is inherently sensitive to changes in arterial PO 2 and PCO 2 or if coronary vascular responses are the result of concomitant increases in myocardial O 2 consumption/demand (MVO 2 ). We hypothesized that the coronary vascular response to PO 2 and PCO 2 would be attenuated in healthy men when MVO 2 was attenuated with β 1 -adrenergic receptor blockade. Healthy men (n=11; age: 25 {plus minus} 1 years) received intravenous esmolol (β 1 -adrenergic receptor antagonist) or volume-matched saline in a double-blind, randomized, crossover study, and were exposed to poikilocapnic hypoxia, isocapnic hypoxia, and hypercapnic hypoxia. Measurements made at baseline and following 5-min of steady state at each gas manipulation included left anterior descending coronary blood velocity (LAD V ; Doppler echocardiography), heart rate and arterial blood pressure. LAD V values at the end of each hypoxic condition were compared between esmolol and placebo. Rate pressure product (RPP) and left-ventricular mechanical energy (ME LV ) were calculated as indices of MVO 2 . All gas manipulations augmented RPP, ME LV , and LAD V but only RPP and ME LV were attenuated (4-18%) following β 1 -adrenergic receptor blockade (P<0.05). Despite attenuated RPP and MELV responses, β 1 -adrenergic receptor blockade did not attenuate the mean LADV vasodilatory response when compared to placebo during poikilocapnic hypoxia (29.4{plus minus}2.2 vs. 27.3{plus minus}1.6 cm/s) and isocapnic hypoxia (29.5{plus minus}1.5 vs. 30.3{plus minus}2.2 cm/s). Hypercapnic hypoxia elicited a feed-forward coronary dilation that was blocked by β 1 -adrenergic receptor blockade. These results indicate a direct influence of arterial PO 2 on coronary vascular regulation that is independent of MVO 2 .

  5. A feasability study of color flow doppler vectorization for automated blood flow monitoring.

    Science.gov (United States)

    Schorer, R; Badoual, A; Bastide, B; Vandebrouck, A; Licker, M; Sage, D

    2017-12-01

    An ongoing issue in vascular medicine is the measure of the blood flow. Catheterization remains the gold standard measurement method, although non-invasive techniques are an area of intense research. We hereby present a computational method for real-time measurement of the blood flow from color flow Doppler data, with a focus on simplicity and monitoring instead of diagnostics. We then analyze the performance of a proof-of-principle software implementation. We imagined a geometrical model geared towards blood flow computation from a color flow Doppler signal, and we developed a software implementation requiring only a standard diagnostic ultrasound device. Detection performance was evaluated by computing flow and its determinants (flow speed, vessel area, and ultrasound beam angle of incidence) on purposely designed synthetic and phantom-based arterial flow simulations. Flow was appropriately detected in all cases. Errors on synthetic images ranged from nonexistent to substantial depending on experimental conditions. Mean errors on measurements from our phantom flow simulation ranged from 1.2 to 40.2% for angle estimation, and from 3.2 to 25.3% for real-time flow estimation. This study is a proof of concept showing that accurate measurement can be done from automated color flow Doppler signal extraction, providing the industry the opportunity for further optimization using raw ultrasound data.

  6. 1-D blood flow modelling in a running human body.

    Science.gov (United States)

    Szabó, Viktor; Halász, Gábor

    2017-07-01

    In this paper an attempt was made to simulate blood flow in a mobile human arterial network, specifically, in a running human subject. In order to simulate the effect of motion, a previously published immobile 1-D model was modified by including an inertial force term into the momentum equation. To calculate inertial force, gait analysis was performed at different levels of speed. Our results show that motion has a significant effect on the amplitudes of the blood pressure and flow rate but the average values are not effected significantly.

  7. Blood flow in curved pipe with radiative heat transfer

    International Nuclear Information System (INIS)

    Ogulu, A.; Bestman, A.R.

    1992-03-01

    Blood flow in a curved pipe such as the aorta is modelled in this study. The aorta is modelled as a curved pipe of slowly varying cross-section. Asymptotic series expansions about a small parameter δ, which is a measure of the curvature ratio is employed to obtain the velocity and temperature distributions. The study simulates the effect of radio-frequency heating, for instance during physiotherapy, on the flow of blood in the cardiovascular system assuming an external constant pressure gradient; and our results agree very well with results obtained by Pedley. (author). 9 refs, 2 figs

  8. Disparity in regional cerebral blood flow during electrically induced seizure

    DEFF Research Database (Denmark)

    Sestoft, D; Meden, P; Hemmingsen, R

    1993-01-01

    This is a presentation of 2 cases in which the intraictal regional cerebral blood flow distribution was measured with the 99mTc-HMPAO single photon emission computerized tomography technique during an electrically induced seizure. Although the seizure was verified as generalized on electroencepha......This is a presentation of 2 cases in which the intraictal regional cerebral blood flow distribution was measured with the 99mTc-HMPAO single photon emission computerized tomography technique during an electrically induced seizure. Although the seizure was verified as generalized...... electroencephalography-verified generalized seizures....

  9. Oscillations and Multiple Equilibria in Microvascular Blood Flow.

    Science.gov (United States)

    Karst, Nathaniel J; Storey, Brian D; Geddes, John B

    2015-07-01

    We investigate the existence of oscillatory dynamics and multiple steady-state flow rates in a network with a simple topology and in vivo microvascular blood flow constitutive laws. Unlike many previous analytic studies, we employ the most biologically relevant models of the physical properties of whole blood. Through a combination of analytic and numeric techniques, we predict in a series of two-parameter bifurcation diagrams a range of dynamical behaviors, including multiple equilibria flow configurations, simple oscillations in volumetric flow rate, and multiple coexistent limit cycles at physically realizable parameters. We show that complexity in network topology is not necessary for complex behaviors to arise and that nonlinear rheology, in particular the plasma skimming effect, is sufficient to support oscillatory dynamics similar to those observed in vivo.

  10. Heterogeneity of cerebral blood flow: a fractal approach

    International Nuclear Information System (INIS)

    Kuikka, J.T.; Hartikainen, P.

    2000-01-01

    Aim: We demonstrate the heterogeneity of regional cerebral blood flow using a fractal approach and single-photon emission computed tomography (SPECT). Method: Tc-99m-labelled ethylcysteine dimer was injected intravenously in 10 healthy controls and in 10 patients with dementia of frontal lobe type. The head was imaged with a gamma camera and transaxial, sagittal and coronal slices were reconstructed. Two hundred fifty-six symmetrical regions of interest (ROIs) were drawn onto each hemisphere of functioning brain matter. Fractal analysis was used to examine the spatial heterogeneity of blood flow as a function of the number of ROIs. Results: Relative dispersion (=coefficient of variation of the regional flows) was fractal-like in healthy subjects and could be characterized by a fractal dimension of 1.17±0.05 (mean±SD) for the left hemisphere and 1.15±0.04 for the right hemisphere, respectively. The fractal dimension of 1.0 reflects completely homogeneous blood flow and 1.5 indicates a random blood flow distribution. Patients with dementia of frontal lobe type had a significantly lower fractal dimension of 1.04±0.03 than in healthy controls. (orig.) [de

  11. Effect of warming and flow rate conditions of blood warmers on red blood cell integrity.

    Science.gov (United States)

    Poder, T G; Pruneau, D; Dorval, J; Thibault, L; Fisette, J-F; Bédard, S K; Jacques, A; Beauregard, P

    2016-11-01

    Fluid warmers are routinely used to reduce the risk of hypothermia and cardiac complications associated with the infusion of cold blood products. However, warming blood products could generate haemolysis. This study was undertaken to compare the impact of temperature of blood warmers on the per cent haemolysis of packed red blood cells (RBCs) heated at different flow rates as well as non-flow conditions. Infusion warmers used were calibrated at 41·5°C ± 0·5°C and 37·5°C ± 0·5°C. Cold RBC units stored at 4°C in AS-3 (n = 30), aged 30-39 days old, were divided into half units before being allocated under two different scenarios (i.e. infusion pump or syringe). Blood warmers were effective to warm cold RBCs to 37·5°C or 41·5°C when used in conjunction with an infusion pump at flow rate up to 600 ml/h. However, when the warmed blood was held in a syringe for various periods of time, such as may occur in neonatal transfusions, the final temperature was below the expected requirements with measurement as low as 33·1°C. Increasing the flow with an infusion pump increased haemolysis in RBCs from 0·2% to up to 2·1% at a flow rate of 600 ml/h regardless of the warming device used (P < 0·05). No relevant increase of haemolysis was observed using a syringe. The use of a blood warmer adjusted to 41·5°C is probably the best choice for reducing the risk of hypothermia for the patient without generating haemolysis. However, we should be cautious with the use of an infusion pump for RBC transfusion, particularly at high flow rates. © 2016 International Society of Blood Transfusion.

  12. Regional cerebral blood flow measurement using a scintillation camera

    International Nuclear Information System (INIS)

    Heiss, W.D.

    1979-01-01

    A scintillation camera connected to auxillary equipment with off-line data processing or connected to an on-line dedicated computer system permits measurement of hemispheric and regional cerebral blood flow. Reliable flow values are obtained from regions limited in size by spatial resolution and the count rates achieved. Flow measurements obtained with the camera are able to resolve inhomogeneities of cerebral circulation in normal subjects. In a variety of clinical conditions, the localization, severity and extent of flow alterations are shown. Results of flow measurements in individual cases elucidate the pathogenesis of neurologic deficits, quantify the damage to the brain, indicate therapeutic measures of potential value and permit an estimation of the further clinical course. With restricted spatial resolution, flow measurements after intravenous 133 Xe injection are also feasible

  13. Nocturnal variations in peripheral blood flow, systemic blood pressure, and heart rate in humans

    DEFF Research Database (Denmark)

    Sindrup, J H; Kastrup, J; Christensen, H

    1991-01-01

    Subcutaneous adipose tissue blood flow rate, together with systemic arterial blood pressure and heart rate under ambulatory conditions, was measured in the lower legs of 15 normal human subjects for 12-20 h. The 133Xe-washout technique, portable CdTe(Cl) detectors, and a portable data storage uni.......0001). The synchronism of the nocturnal subcutaneous hyperemia and the decrease in systemic mean arterial blood pressure point to a common, possibly central nervous or humoral, eliciting mechanism.......Subcutaneous adipose tissue blood flow rate, together with systemic arterial blood pressure and heart rate under ambulatory conditions, was measured in the lower legs of 15 normal human subjects for 12-20 h. The 133Xe-washout technique, portable CdTe(Cl) detectors, and a portable data storage unit...

  14. Esophageal blood flow in the cat. Normal distribution and effects of acid perfusion

    International Nuclear Information System (INIS)

    Hollwarth, M.E.; Smith, M.; Kvietys, P.R.; Granger, D.N.

    1986-01-01

    The radioactive microsphere technique was used to estimate blood flow to different regions of the esophagus and to adjacent regions of the stomach before and after perfusion of the esophagus with hydrochloric acid (pH 1.5) for 5 min. Under resting conditions total blood flow, as well as blood flow to the mucosal-submucosal layer and the muscular layer, to both sphincters was significantly higher than to the esophageal body. Blood flow to the adjacent regions of the stomach was significantly higher than esophageal blood flow. Acid perfusion resulted in a large increase in total blood flow in both sphincters and the lower esophageal body. Gastric blood flow was not altered by acid perfusion. The esophageal hyperemia resulted primarily from an increase in blood flow to the muscular layer; mucosal-submucosal blood flow was increased only in the lower esophageal sphincter. The present study indicates that short periods (5 min) of gastroesophageal reflux may increase esophageal blood flow

  15. The Effects Of L-Arginine And L-Name On Coronary Flow And Oxidative Stress In Isolated Rat Hearts

    Directory of Open Access Journals (Sweden)

    Sobot Tanja

    2015-12-01

    Full Text Available The aim of this experimental study was to assess the effects of the acute administration of L-arginine alone and in combination with L-NAME (a non-selective NO synthase inhibitor on the coronary flow and oxidative stress markers in isolated rat hearts. The experimental study was performed on hearts isolated from Wistar albino rats (n=12, male, 8 weeks old, body mass of 180-200 g. Retrograde perfusion of the isolated preparations was performed using a modified method according to the Langendorff technique with a gradual increase in the perfusion pressure (40–120 cmH2O. The following values were measured in the collected coronary effluents: coronary flow, released nitrites (NO production marker, superoxide anion radical and the index of lipid peroxidation (measured as thiobarbiturate reactive substances. The experimental protocol was performed under controlled conditions, followed by the administration of L-arginine alone (1 mmol and L-arginine (1 mmol + L-NAME (30 μmol. The results indicated that L-arginine did not significantly increase the coronary flow or the release of NO, TBARS and the superoxide anion radical. These effects were partially blocked by the joint administration of L-arginine + L-NAME, which indicated their competitive effect. Hence, the results of our study do not demonstrate significant effects of L-arginine administration on the coronary flow and oxidative stress markers in isolated rat hearts.

  16. The Relationship Between Serum Endocan Levels With the Presence of Slow Coronary Flow: A Cross-Sectional Study.

    Science.gov (United States)

    Kundi, Harun; Gok, Murat; Kiziltunc, Emrullah; Topcuoglu, Canan; Cetin, Mustafa; Cicekcioglu, Hulya; Ugurlu, Burcu; Ulusoy, Feridun Vasfi

    2017-07-01

    The aim of this study was to investigate the relationship between endocan levels with the presence of slow coronary flow (SCF). In this cross-sectional study, a total of 88 patients, who admitted to our hospital, were included in this study. Of these, 53 patients with SCF and 35 patients with normal coronary flow were included in the final analysis. Coronary flow rates of all patients were determined by the Timi Frame Count (TFC) method. In correlation analysis, endocan levels revealed a significantly positive correlation with high sensitive C-reactive protein and corrected TFC. In multivariate logistic regression analysis, the endocan levels were found as independently associated with the presence of SCF. Finally, using a cutoff level of 2.3, endocan level predicted the presence of SCF with a sensitivity of 77.2% and specificity of 75.2%. In conclusion, our study showed that higher endocan levels were significantly and independently related to the presence of SCF.

  17. Restrictive versus liberal blood transfusion in patients with coronary artery disease: a meta-analysis.

    Science.gov (United States)

    Wang, Yushu; Shi, Xiuli; Wen, Meiqin; Chen, Yucheng; Zhang, Qing

    2017-04-01

    To compare clinical outcomes between restrictive versus liberal blood transfusion strategies in patients with coronary artery disease (CAD). A literature search from January 1966 to May 2016 was performed in PubMed, EMBASE and Cochrane Library to find trials evaluating a restrictive hemoglobin transfusion trigger of ≤8 g/dL, compared with a more liberal trigger. Two study authors independently extracted data from the trials. The primary outcome was mortality and the secondary outcome was subsequent myocardial infarction. Relative risks (RRs) with their 95% confidence intervals (CIs) were assessed. Six trials involving 133,058 participants were included in this study. Pooled results revealed no difference in mortality between the liberal transfusion and restrictive transfusions (RR = 1.17, 95% CI = 0.91-1.52, P = .22). Subgroup analysis revealed that a restrictive transfusion strategy was associated with a higher risk of in-hospital mortality (RR = 1.38, 95% CI = 1.15-1.67, P transfusion strategy and restrictive transfusion strategy in risk for subsequent myocardial infarction (RR = 1.09, 95% CI = 0.57-2.06, P = .80). Limitations include (1) limited number of trials, especially those evaluating myocardial infarction, (2) observed heterogeneity, (3) confounding by indication and other inherent bias may exist. The findings suggest that restrictive blood transfusion was associated with higher in-hospital and 30 day mortality than liberal blood transfusion in CAD patients. The conclusions are mainly based on retrospective studies and should not be considered as recommendation before they are supported by randomized controlled trials.

  18. Recovery of testicular blood flow following ligation of testicular vessels

    International Nuclear Information System (INIS)

    Pascual, J.A.; Villanueva-Meyer, J.; Salido, E.; Ehrlich, R.M.; Mena, I.; Rajfer, J.

    1989-01-01

    To determine whether initial ligation of the testicular vessels of the high undescended testis followed by a delayed secondary orchiopexy is a viable alternative to the classical Fowler-Stephens procedure, a series of preliminary experiments were conducted in the rat in which testicular blood flow was measured by the 133-xenon washout technique before, and 1 hour and 30 days after ligation of the vessels. In addition, testicular histology, and testis and sex-accessory tissue weights were measured in 6 control, 6 sham operated and 6 testicular vessel ligated rats 54 days after vessel ligation. The data demonstrate that ligation and division of the testicular blood vessels produce an 80 per cent decrease in testicular blood flow 1 hour after ligation of the vessels. However, 30 days later testis blood flow returns to the control and pre-treatment value. There were no significant changes in testis or sex-accessory tissue weights 54 days after vessel ligation. Histologically, 4 of the surgically operated testes demonstrated necrosis of less than 25 per cent of the seminiferous tubules while 1 testis demonstrated more than 75 per cent necrosis. The res