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Sample records for low-pressure balloon angioplasty

  1. Low-pressure balloon angioplasty with adjuvant pharmacological therapy in patients with acute ischemic stroke caused by intracranial arterial occlusions

    Energy Technology Data Exchange (ETDEWEB)

    Nogueira, Raul G. [Massachusetts General Hospital, Harvard Medical School, Department of Radiology, Endovascular Neurosurgery/Interventional Neuroradiology Section, Boston, MA (United States); Massachusetts General Hospital, Harvard Medical School, Department of Neurosurgery, Endovascular Neurosurgery/Interventional Neuroradiology Section, Boston, MA (United States); Massachusetts General Hospital, Harvard Medical School, Department of Neurology, Neurocritical Care and Vascular Neurology Section, Boston, MA (United States); Massachusetts General Hospital, Boston, MA (United States); Schwamm, Lee H.; Buonanno, Ferdinando S.; Koroshetz, Walter J. [Massachusetts General Hospital, Harvard Medical School, Department of Neurology, Neurocritical Care and Vascular Neurology Section, Boston, MA (United States); Yoo, Albert J.; Rabinov, James D.; Pryor, Johnny C.; Hirsch, Joshua A. [Massachusetts General Hospital, Harvard Medical School, Department of Radiology, Endovascular Neurosurgery/Interventional Neuroradiology Section, Boston, MA (United States); Massachusetts General Hospital, Harvard Medical School, Department of Neurosurgery, Endovascular Neurosurgery/Interventional Neuroradiology Section, Boston, MA (United States)

    2008-04-15

    The use of coronary balloons in the cerebral vasculature is limited due to their poor trackability and increased risk of vessel injury. We report our experience using more compliant elastomer balloons for thrombus resistant to intraarterial (IA) pharmacological and mechanical thrombolysis in acute stroke. We retrospectively analyzed 12 consecutive patients with an occluded intracranial artery treated with angioplasty using a low-pressure elastomer balloon. Angiograms were graded according to the Thrombolysis in Cerebral Infarction (TICI) and Qureshi grading systems. Outcomes were categorized as independent (modified Rankin scale, mRS, score {<=}2), dependent (mRS score 3-5), or dead (mRS score 6). Included in the study were 12 patients (mean age 66{+-}17 years, range 31-88 years; mean baseline National Institutes of Health stroke scale score 17{+-}3, range 12-23). The occlusion sites were: internal carotid artery (ICA) terminus (five patients, including two concomitant cervical ICA occlusions), M1 segment (two patients), and basilar artery (two patients). Pharmacological treatment included intravenous (IV) t-PA only (two patients), IA urokinase only (nine patients), both IV t-PA and IA urokinase (one patient), and IV and/or IA eptifibatide (eight patients). Mean time to treatment was 5.9{+-}3.9 h (anterior circulation) and 11.0{+-}7.2 h (posterior circulation). Overall recanalization rate (TICI grade 2/3) was 91.6%. Procedure-related morbidity occurred in one patient (distal posterior inferior cerebellar artery embolus). There were no symptomatic hemorrhages. Outcomes at 90 days were independent (five patients), dependent (three patients) and dead (four patients, all due to progression of stroke with withdrawal of care). Angioplasty of acutely occluded intracranial arteries with low-pressure elastomer balloons results in high recanalization rates with an acceptable degree of safety. Prior use of thrombolytics may increase the chances of recanalization, and

  2. Cutting balloon angioplasty for intrastent restenosis treatment

    Directory of Open Access Journals (Sweden)

    João Orávio de Freitas Jr

    1999-05-01

    Full Text Available We describe here two patients with angiographic diagnosis of intrastent restenosis and regional myocardial ischemia. One stent restenosis was located in a native coronary artery and the other in a vein graft. Both were treated with cutting balloon angioplasty (CBA, inflated at low pressures. Angiographic success was obtained and both patients were discharged in the day after the procedure. Cutting balloon angioplasty using low inflation pressures achieved important luminal gains, in these two cases of intrastent restenosis. Further studies are necessary before the effectiveness of this procedure can be precisely defined.

  3. Pseudoperforation during kissing balloon angioplasty.

    Science.gov (United States)

    Panetta, Carmelo J; Fasseas, Panayotis; Raveendran, Ganesh; Garratt, Kirk N

    2004-11-01

    We describe a case of apparent perforation during kissing balloon angioplasty of a bifurcation lesion. There was no evidence of perforation on follow-up angiography or via intravascular ultrasound. Possible etiologies include minimal perforation that immediately sealed postdeflation or forced contrast into the microvascular bed via a proximal side branch.

  4. MRI temperature mapping during thermal balloon angioplasty.

    Science.gov (United States)

    Shmatukha, Andriy V; Bakker, Chris J G

    2006-04-21

    Knowledge on the thermal dose delivered during thermal balloon angioplasty (TBA) is desirable to understand why TBA's outcome varies widely among patients and why it is subject to high restenosis rates. In its conventional implementation, TBA involves injection of a heated medium into a balloon positioned within a stenotic blood vessel. The medium injection causes flow, motion and susceptibility-redistribution artefacts that are devastating to the proton resonance frequency shift (PRFS) technique of MRI temperature mapping. Here, we propose to separate in time medium injection and heating by first inflating a balloon with a medium at an initial temperature, and then by heating the medium up using laser light. The separation is shown to eliminate all the mentioned artefacts and to enable real-time MRI temperature mapping using the PRFS technique. Accurate and reliable temperature maps were acquired in a TBA balloon itself and in the surrounding phantom tissue during heat application.

  5. Management of failed angioplasty with laser balloon angioplasty

    Science.gov (United States)

    Jenkins, Ronald D.; Spears, J. Richard

    1990-07-01

    Laser balloon angioplasty (LBA) is a technique for improving the post angioplasty result by the radial diffusion of continuous wave Neodymium:YAG laser energy to the arterial wall during the final inflation of percutaneous transluminal coronary angioplasty (PTCA). Potential mechanisms of luminal improvement include sealing of dissections, reduction of arterial recoil, desiccation of thrombus, and reduction of thrombogenicity of tissues at the luminal surface. These effects are helpful in the management of failed PTCA as defined by the presence of a greater than 50% stenosis after conventional PTCA. Preliminary data suggest that LBA may be safe and effective for the treatment of abrupt closure, with a majority of patients successfully avoiding emergency coronary artery bypass surgery. Similarly, a cohort in which the residual post-PTCA luminal diameter was less than 50% of reference diameter (n=13) was subsequently treated with LBA and demonstrated uniform success in improving luminal diameter, with a mean increment of 0.9mm. Data on the long-term clinical outcome of this cohort is encouraging.

  6. Vessel wall temperature estimation for novel short term thermal balloon angioplasty: study of thermal environment.

    Science.gov (United States)

    Kaneko, Kenji; Nakatani, Eriko; Futami, Hikaru; Ogawa, Yoshifumi; Arai, Tsunenori; Fukui, Masaru; Shimamura, Satoshi; Kawabata, Takashi

    2005-01-01

    We have been proposing novel thermal balloon angioplasty, photo-thermo dynamic balloon angioplasty (PT-DBA). PTDBA realized thermal injury and low pressure dilatation that can prevent restenosis in chronic phase. We aim to determine the most efficient heating condition suit to individual symptom with pre-operation thermal simulation. We analyzed the flow dynamics and heat convection inside the balloon, and investigated heat conduction of balloon film to establish the temperature estimation method among vessel wall. Compared with ex vivo temperature measurement experiment, we concluded that the factors need to be considered for the establishment would be the heat conduction of the flow inside PTDB, heat conduction at the balloon film, and contact thermal resistance between the balloon film and vessel wall.

  7. AUTOPERFUSION BALLOON CATHETER FOR COMPLICATED CORONARY ANGIOPLASTY - A PROSPECTIVE-STUDY WITH RETROSPECTIVE CONTROLS

    NARCIS (Netherlands)

    DEMUINCK, ED; VANDIJK, RB; DENHEIJER, P; MEEDER, JG; LIE, KI

    1992-01-01

    Prolonged angioplasty balloon inflation with an autoperfusion balloon for failed conventional coronary angioplasty, was compared with emergency surgery for this condition. Restenosis was assessed 6 weeks after successful intervention with the autoperfusion balloon. Forty consecutive patients with pe

  8. AUTOPERFUSION BALLOON CATHETER FOR COMPLICATED CORONARY ANGIOPLASTY - A PROSPECTIVE-STUDY WITH RETROSPECTIVE CONTROLS

    NARCIS (Netherlands)

    DEMUINCK, ED; VANDIJK, RB; DENHEIJER, P; MEEDER, JG; LIE, KI

    1992-01-01

    Prolonged angioplasty balloon inflation with an autoperfusion balloon for failed conventional coronary angioplasty, was compared with emergency surgery for this condition. Restenosis was assessed 6 weeks after successful intervention with the autoperfusion balloon. Forty consecutive patients with

  9. Absence of Bacteria on Coronary Angioplasty Balloons from Unselected Patients

    DEFF Research Database (Denmark)

    Hansen, Gorm Mørk; Nilsson, Martin; Nielsen, Claus Henrik

    2015-01-01

    if bacterial DNA from primarily oral bacteria could be detected on coronary angioplasty balloons by use of an optimized sampling process combined with an internally validated sensitive polymerase chain reaction (PCR) assay. Coronary angioplasty balloons and control samples from a total of 45 unselected...... angioplasty balloons are unlikely to be useful for detection of bacteria with current PCR techniques in unselected patients with coronary artery disease, more studies are warranted to determine the extent to which bacteria contribute to atherosclerosis and its clinical manifestations and whether the presence......, and translocation of bacteria from the oral cavity to the coronary arteries may play a role in the development of coronary artery disease. Very few studies have used angioplasty balloons for in vivo sampling from diseased coronary arteries, and with varying results. Therefore, the aim of this study was to assess...

  10. A Rare and Serious Unforeseen Complication of Cutting Balloon Angioplasty

    Directory of Open Access Journals (Sweden)

    Praveen Vemula

    2014-01-01

    Full Text Available Cutting balloon angioplasty (CBA is one of the adept ways of treating “in-stent restenosis.” Various complications related to cutting balloon angioplasty have been reported including arterial rupture, delayed perforation and fracture of microsurgical blades. Here we report a very unusual and inadvertent extraction of a stent previously deployed in the ramus intermedius coronary branch by a cutting balloon catheter. This required repeat stenting of the same site for an underlying dissection. Even though stent extraction is a rare complication it can be serious due to dissection, perforation, and closure of the artery. Physicians performing coronary artery interventions would need to be aware of this rare and serious complication especially if any difficulty is encountered while withdrawing the cutting balloon. Therefore, after removal, cutting balloon should be examined thoroughly for possible stent dislodgment or extraction when used for “in-stent restenosis.”

  11. Human percutaneous and intraoperative laser thermal angioplasty: initial clinical results as an adjunct to balloon angioplasty.

    Science.gov (United States)

    Sanborn, T A; Greenfield, A J; Guben, J K; Menzoian, J O; LoGerfo, F W

    1987-01-01

    In this study, the safety and efficacy of percutaneous laser thermal angioplasty as an adjunct to balloon angioplasty were investigated in 13 patients with severe peripheral vascular disease. By means of a novel fiberoptic laser delivery system (Laserprobe) in which argon laser energy is converted to heat in a metallic tip at the end of the fiberoptic fiber, improvement in the angiographic luminal diameter was noted in 14 of 15 femoropopliteal vessels (93%) by delivering 8 to 13 watts of continuous argon laser energy as the Laserprobe was advanced through the lesion. Initial clinical success (indicated by relief of symptoms and increase in Doppler index) for the combined laser and balloon angioplasty procedures was obtained in 12 of 15 vessels (80%), with inadequate balloon dilatation being the limiting factor in three patients. No significant complications of vessel perforation, dissection, pain, spasm, or embolization of debris occurred. Of the 12 patients who had procedures with initial angiographic and clinical success, 10 (83%) were asymptomatic in the initial follow-up period of 1 to 9 months (mean 6 months). Thus, laser thermal angioplasty with a Laserprobe is a safe and effective adjunct to peripheral balloon angioplasty. This technique has the potential to increase the initial success rate of angioplasty for lesions that are difficult or impossible to treat by conventional means. By removing most of the obstructing lesion, this technique may also reduce recurrent stenosis.

  12. Cutting balloon angioplasty vs. conventional balloon angioplasty in patients receiving intracoronary brachytherapy for the treatment of in-stent restenosis.

    Science.gov (United States)

    Fasseas, Panayotis; Orford, James L; Lennon, Ryan; O'Neill, Jessica; Denktas, Ali E; Panetta, Carmelo J; Berger, Peter B; Holmes, David R

    2004-10-01

    The objective of this study was to evaluate the safety and efficacy of cutting balloon angioplasty (CBA) for the treatment of in-stent restenosis prior to intracoronary brachytherapy (ICB). Cutting balloon angioplasty may reduce the incidence of uncontrolled dissection requiring adjunctive stenting and may limit "melon seeding" and geographic miss in patients with in-stent restenosis who are subsequently treated with ICB. We performed a retrospective case-control analysis of 134 consecutive patients with in-stent restenosis who were treated with ICB preceded by either CBA or conventional balloon angioplasty. We identified 44 patients who underwent CBA and ICB, and 90 control patients who underwent conventional percutaneous transluminal coronary angioplasty (PTCA) and ICB for the treatment of in-stent restenosis. Adjunctive coronary stenting was performed in 13 patients (29.5%) in the CBA/ICB group and 41 patients (45.6%; P 0.05). Despite sound theoretical reasons why CBA may be better than conventional balloon angioplasty for treatment of in-stent restenosis with ICB, and despite a reduction in the need for adjunctive coronary stenting, we were unable to identify differences in clinical outcome.

  13. A technical strategy for carotid artery stenting: suboptimal prestent balloon angioplasty without poststenting balloon dilatation.

    Science.gov (United States)

    Jin, Sung-Chul; Kwon, O-Ki; Oh, Chang Wan; Jung, Cheolkyu; Han, Moon Gu; Bae, Hee-Joon; Lee, Sang Hyung; Jung, Young Sub; Han, Moon Hee; Kang, Hyun-Seung

    2010-11-01

    Traditional carotid artery stenting (CAS) consists of predilatation, optional deployment of embolic protection devices, stenting, and poststent angioplasty. Each step carries a risk of thromboembolism. To design a new and simplified procedural protocol, suboptimal balloon angioplasty without routine poststenting balloon dilatation, and to describe the efficacy this protocol in terms of procedural risks and angiographic and clinical outcomes. Over a period of 6 years, 161 carotid artery stenoses in 156 consecutive patients were treated by CAS with embolic protection devices. Among them, 110 lesions in 107 patients (68.3%) were treated by our simplified method (symptomatic, > 50% stenosis; asymptomatic, > 70% stenosis). Overall, 98 lesions (88.3%) had severe stenosis (> 70%). The mean stenosis was reduced from 77% to 10% after CAS. A persistent neurological deficit developed in 2 patients from thromboembolism. Hemodynamic insufficiency developed in 14 lesions during CAS (12.7%). The ipsilateral stroke and mortality rate was 4.5% within 1 month after CAS (asymptomatic, 3.6%; symptomatic, 4.8%). Over a mean of 19 months of follow-up, additive angioplasty was performed in 2 patients as a result of progressive restenosis (≥ 50%). A comparison of the balloon sizes of the prestent angioplasty for group 1 (balloon, ≤ 4 mm) and group 2 (balloon, ≥ 5 mm) showed no difference in restenosis between the groups at 15 months of follow-up after CAS. Our CAS technique with suboptimal prestenting angioplasty without routine use of poststenting dilatation is safe, simple, and efficient with acceptable risks.

  14. Balloon Angioplasty for Intracranial Atherosclerotic Disease: A Multicenter Study

    Science.gov (United States)

    Karanam, Lakshmi Sudha Prasanna; Sharma, Mukesh; Alurkar, Anand; Baddam, Sridhar Reddy; Pamidimukkala, Vijaya; Polavarapu, Raghavasarma

    2017-01-01

    Aim To evaluate the role and efficacy of the balloon angioplasty in intracranial atherosclerotic disease (ICAD) in patients who presented with acute stroke due to vessel occlusion and in patients with symptomatic disease despite optimum medical management. Methods From 2013 to 2016, a total of 39 patients (24 males and 15 females with a mean age of 64.5 years) underwent balloon angioplasty over a period of 2 years and 8 months in three different institutions in India. Maverick balloon catheter (Boston scientific) is used in all the patients. MRI brain with MR angiogram was done in all the patients prior to intervention. Twenty-three patients who had underlying severe ICAD presented with acute stroke due to vessel occlusion. Sixteen patients presented with symptomatic ICAD with recurrent ischemic attack due to the progressing underlying disease despite optimum medical management. Technical success, peri-procedural events, and clinical outcomes were documented for all the patients. Results Technical success (residual stenosis 90% of the patients. MR angiogram on follow-up of nine months was done in 26 patients, and none of them had restenosis. Conclusion Balloon angioplasty is a safe option and can be effectively used in patients of ICAD with acceptable risks and promising outcomes. PMID:28702117

  15. A randomized comparison of balloon angioplasty versus rotational atherectomy in complex coronary lesions (COBRA study)

    National Research Council Canada - National Science Library

    Dill, T; Dietz, U; Hamm, C W; Küchler, R; Rupprecht, H J; Haude, M; Cyran, J; Ozbek, C; Kuck, K H; Berger, J; Erbel, R

    2000-01-01

    .... The Comparison of Balloon-Angioplasty versus Rotational Atherectomy study (COBRA) is a multicentre, prospective, randomized trial to compare short- and long-term effects of percutaneous transluminal coronary angioplasty (PTCA...

  16. Prevention of restenosis after coronary balloon angioplasty: rationale and design of the Fluvavastatin Angioplasty Restenosis (FLARE) Trial

    NARCIS (Netherlands)

    J.J.R.M. Bonnier (Hans); G. Jackson (Graham); C.M. Miguel (Carlos); J. Shepherd; M.C. Vrolix (Mathias); P.W.J.C. Serruys (Patrick); D.P. Foley (David)

    1994-01-01

    textabstractPrevention of restenosis after successful percutaneous transluminal coronary balloon angioplasty (PTCA) continues to present the greatest therapeutic challenge in interventional cardiology. Experimental and pathological studies describe restenosis as no more than the biologic healing res

  17. Radiofrequency balloon angioplasty. Rationale and proof of principle

    Energy Technology Data Exchange (ETDEWEB)

    Becker, G.J.; Lee, B.I.; Waller, B.F.; Barry, K.J.; Kaplan, J.; Connolly, R.; Dreesen, R.G.; Nardella, P.

    1988-11-01

    Post-angioplasty restenosis (PARS) in atherosclerotic lesions of medium and small arteries occurs in about one-third of cases in the first year following percutaneous transluminal angioplasty (PTA) (early PARS). PARS includes acute spasm, dissection with reclosure, elastic recoil, fibrocellular proliferative response, and progressive atheromatous disease. Fibrocellular proliferation (possibly initiated by platelet derived growth factor) is felt to be culpable in many cases of early PARS (months). Pharmacologic regimens, stents, and thermal welding of the intimal-medial cracks of PTA are among the interventions being developed to deal with PARS. Radiofrequency (RF) current as a source of thermal energy may be useful in combination with balloon angioplasty to reduce PARS. Ideally, this combination would (1) weld intimal-medial cracks of PTA; (2) mold plaque and normal vessel to increase lumen diameters without creating intimal-medial cracks; and (3) destroy medial smooth muscle cells and multipotential cells (cellular substrate of PARS). Canine in vivo studies have established the feasibility of RF-mediated vascular tissue welding. Human aortic specimens (N = 28) were manually dissected into intima-media and media-adventitia layers. Bipolar RF energy (650 KHz, total 300 J) and mechanical pressure (1 atm) (experimental group, N = 24) or mechanical pressure alone (control group, N = 4) were applied to the reapposed specimen layers in a special chamber. The chamber was modified with a bipolar electrode designed to reproduce that planned for an RF balloon angioplasty catheter. Welding was demonstrated in normal and atherosclerotic treated specimens (23/24 or 96%) but not controls (0/4).

  18. Modeling plaque fissuring and dissection during balloon angioplasty intervention.

    Science.gov (United States)

    Gasser, T Christian; Holzapfel, Gerhard A

    2007-05-01

    Balloon angioplasty intervention is traumatic to arterial tissue. Fracture mechanisms such as plaque fissuring and/or dissection occur and constitute major contributions to the lumen enlargement. However, these types of mechanically-based traumatization of arterial tissue are also contributing factors to both acute procedural complications and chronic restenosis of the treatment site. We propose physical and finite element models, which are generally useable to trace fissuring and/or dissection in atherosclerotic plaques during balloon angioplasty interventions. The arterial wall is described as an anisotropic, heterogeneous, highly deformable, nearly incompressible body, whereas tissue failure is captured by a strong discontinuity kinematics and a novel cohesive zone model. The numerical implementation is based on the partition of unity finite element method and the interface element method. The later is used to link together meshes of the different tissue components. The balloon angioplasty-based failure mechanisms are numerically studied in 3D by means of an atherosclerotic-prone human external iliac artery, with a type V lesion. Image-based 3D geometry is generated and tissue-specific material properties are considered. Numerical results show that in a primary phase the plaque fissures at both shoulders of the fibrous cap and stops at the lamina elastica interna. In a secondary phase, local dissections between the intima and the media develop at the fibrous cap location with the smallest thickness. The predicted results indicate that plaque fissuring and dissection cause localized mechanical trauma, but prevent the main portion of the stenosis from high stress, and hence from continuous tissue damage.

  19. Treatment of benign ureteral stricture by double J stents using high-pressure balloon angioplasty

    Institute of Scientific and Technical Information of China (English)

    YU Hua-liang; YE Lin-yang; LIN Mao-hu; YANG Yu; MIAO Rui; HU Xiao-juan

    2011-01-01

    Background Balloon dilatation angioplasty is a minimally invasive surgery for treating benign ureteral stricture. The aim of this study was to investigate the effect of placing double J (D-J) stents using high-pressure balloon angioplasty in treating benign ureteral stricture.Methods A total of 42 patients (48 cases) with benign ureteral stricture (42 had benign ureteral stricture) were investigated by inserting dual D-J stents using high-pressure balloon angioplasty. The control group contained 50 patients (57 cases) employing the conventional balloon angioplasty with a single D-J stent inserted for comparison.Results The overall effective rate of the treated and control groups was 87.8% (36/41) and 62.7% (32/51), respectively (P <0.05).Conclusion This new approach produces a better curative effect than the conventional balloon angioplasty with a single D-J stent insertion in treating benign ureteral stricture.

  20. Balloon pulmonary angioplasty in chronic thromboembolic pulmonary hypertension

    Directory of Open Access Journals (Sweden)

    Irene Lang

    2017-03-01

    Full Text Available Chronic thromboembolic pulmonary hypertension (CTEPH is thought to result from incomplete resolution of pulmonary thromboemboli that undergo organisation into fibrous tissue within pulmonary arterial branches, filling pulmonary arterial lumina with collagenous obstructions. The treatment of choice is pulmonary endarterectomy (PEA in CTEPH centres, which has low post-operative mortality and good long-term survival. For patients ineligible for PEA or who have recurrent or persistent pulmonary hypertension after surgery, medical treatment with riociguat is beneficial. In addition, percutaneous balloon pulmonary angioplasty (BPA is an emerging option, and promises haemodynamic and functional benefits for inoperable patients. In contrast to conventional angioplasty, BPA with undersized balloons over guide wires exclusively breaks intraluminal webs and bands, without dissecting medial vessel layers, and repeat sessions are generally required. Observational studies report that BPA improves haemodynamics, symptoms and functional capacity in patients with CTEPH, but controlled trials with long-term follow-up are needed. Complications include haemoptysis, wire injury, vessel dissection, vessel rupture, reperfusion pulmonary oedema, pulmonary parenchymal bleeding and haemorrhagic pleural effusions. This review summarises the available evidence for BPA, patient selection, recent technical refinements and periprocedural imaging, and discusses the potential future role of BPA in the management of CTEPH.

  1. A comparison of balloon-expandable-stent implantation with balloon angioplasty in patients with coronary artery disease. Benestent Study Group.

    OpenAIRE

    Serruys, P.W.; de Jaegere, P; Kiemeneij, F.; Macaya, C; Rutsch, W; Heyndrickx, G.; Emanuelsson, H.; Marco, J.; Legrand, Victor; Materne, P.

    1994-01-01

    BACKGROUND: Balloon-expandable coronary-artery stents were developed to prevent coronary restenosis after coronary angioplasty. These devices hold coronary vessels open at sites that have been dilated. However, it is unknown whether stenting improves long-term angiographic and clinical outcomes as compared with standard balloon angioplasty. METHODS: A total of 520 patients with stable angina and a single coronary-artery lesion were randomly assigned to either stent implantation (262 patients)...

  2. Angioplasty with drug coated balloons for the treatment of infrainguinal peripheral artery disease.

    Science.gov (United States)

    Werner, Martin

    2016-09-01

    Restenosis or re-occlusion after femoropopliteal angioplasty or stent implantation is the main limitation of endovascular treatment strategies for peripheral artery disease. Within the last years, balloon catheters with anti-proliferative drug coating on the balloon surface have shown to be associated with higher patency rates compared to plain balloon angioplasty. Thus, drug-coated balloons were gradually adopted in many interventional centres for the treatment of femoropopliteal obstructions. The current review summarises the existing evidence for drug-coated balloons in the infrainguinal vessels and their indication in special lesion cohorts.

  3. Parallel wire balloon angioplasty for undilatable venous stenosis in hemodialysis fistula

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Tae Beom; You, Jin Jong; Cho, Jae Min [Gyeongsang National University Hospital, Jinju (Korea, Republic of)] (and others)

    2007-05-15

    The purpose of this study was to assess the value of the parallel wire balloon angioplasty technique for treating dysfunctional hemdialysis fistula with rigid stenosis, and this type of lesion was resistant to conventional angioplasty. Between March 2002 and August 2003, we included 6 patients (mean age: 59, males: 2, females: 4) who were treated via parallel the wire balloon angioplasty technique and their hemodialysis fistula has stenoses that were resistant to conventional angioplasty. We performed conventional angioplasty in all patients, but we failed to achieve sufficient dilatation. In the cases of highly resistant stenosis, an additional 0.016 inch wire was inserted into the 7 F vascular sheath. During angioplasty, a 0.016 inch guide wire was inserted between the balloon and the stenosis and then it was pushed to and fro until the balloon indentation disappeared. After the procedure, we performed angiography to identify the residual stenosis and the procedure-related complications. The undilatable stenoses in 5 patients were successfully resolved without complications via the parallel wire angioplasty technique. In one patient, indentation of balloon was not resolved, but the residual stenosis was both minimal and hemodynamically insignificant. The parallel wire angioplasty technique seems to be a feasible and cost-effective method for treating a dysfunctional hemodialysis fistula with undilatable and rigid stenosis.

  4. Prediction of Outcome after Femoropopliteal Balloon Angioplasty by Intervascular Ultrasound

    DEFF Research Database (Denmark)

    Schroeder, Torben Veith; Vogt, Katja; Just, S.;

    1997-01-01

    original, intravascular ultrasound, percutaneous transluminal angioplasty, peripheral arteries, plaquemorphology, prediction of outcome......original, intravascular ultrasound, percutaneous transluminal angioplasty, peripheral arteries, plaquemorphology, prediction of outcome...

  5. Primary balloon angioplasty plus balloon angioplasty maturation to upgrade small-caliber veins (<3 mm) for arteriovenous fistulas.

    Science.gov (United States)

    De Marco Garcia, Lorena P; Davila-Santini, Luis R; Feng, Qin; Calderin, Julio; Krishnasastry, Kambhampaty V; Panetta, Thomas F

    2010-07-01

    Small-diameter veins are often a limiting factor for the successful creation of arteriovenous fistulas (AVFs). This study evaluated the use of intraoperative primary balloon angioplasty (PBA) as a technique to upgrade small-diameter veins during AVF creation. Sequential balloon angioplasty maturation (BAM) was evaluated as a technique to salvage failed fistulas, expedite maturation, and improve the patency of AVFs after PBA. Sixty-two PBAs were performed in 55 patients with an intent-to-treat using an all-autologous policy. PBAs of veins were performed just before AVF creation using 2.5- to 4-mm angioplasty balloons (1- to 1.5-mm larger than the nominal vein diameter). PBAs were performed through the spatulated end of the vein for a length of up to 8 cm using hydrophilic guidewires and hand inflations without fluoroscopy. BAM was performed in 53 of the 62 PBAs at 2, 4, and 6 weeks after the PBA. Successful outcome was determined as the functional ability to use the fistula for hemodialysis without surgical revision. Of the 62 PBAs, 53 (85.4%), comprising 47 of the original AVFs and 6 new site AVFs created at other sites, remained patent and subsequently underwent BAM with a resulting functional AVF. Fifteen of the 47 original AVFs: 14 due to occlusion; one AVF with a steal was ligated. Seven of the 14 fistulas that occluded were salvaged using recanalization techniques during sequential BAMs. Two of the seven fistulas that were not salvaged required AVGs (3%), and five patients underwent redo AVFs using alternative veins. These five cases were also performed using PBAs and BAMs technique. One patient with a functioning fistula underwent intentional ligation for steal syndrome and also underwent an alternative site AVF, PBA, and BAM. At 3 months, 53 AVFs were functional and successfully used for dialysis. Overall, a working AVF was obtained at the initial site in 47 of 55 patients (85.4%), and 53 (96.3%) received working AVFs that were functioning for dialysis

  6. Balloon Angioplasty Versus Surgical Repair of Coarctation of Aorta in Infants

    Directory of Open Access Journals (Sweden)

    Fariba Alaei

    2011-09-01

    Full Text Available Background: Coarctation of the aorta is a discrete stenosis of the proximal thoracic aorta. The common clinical pattern is congestive heart failure in infancy. Treatment methods include balloon angioplasty and surgical repair in this age group. Percutaneous balloon angioplasty is a less invasive method for the repair of discrete coarctation but remains controversial as a primary treatment strategy for a native coarctation. This study aimed to compare the effectiveness and outcome of balloon angioplasty and surgical repair in coarctation infants younger than 1 year old.Methods: This retrospective study evaluated the results of the two methods in 167 patients younger than one year old admitted into a tertiary heart center pediatric ward with the diagnosis of coarctation of the aorta: Balloon angioplasty was done for 55 and surgical repair for 112 infants. Patients with previous interventions were not included in this study. Results: Primary results revealed no significant difference in the effectiveness of the two methods (p value = 0.0601. While the rate of recurrent coarctation was significantly lower in the surgery group [19 (17% vs. 11 (20%, p value = 0.0470], the mortality rate was lower in the balloon angioplasty method [5 (5.5% vs. 13 (11.6%, p value = 0.039]. Our multivariate logistic regression model, however, showed no statistically significant difference (p value = 0.120.Conclusion: Because of the incidence of re-coarctation, balloon angioplasty compared with surgical repair did not confer an improved outcome for our infants’ coarctation.

  7. Influence of inflation pressure and balloon size on the development of intimal hyperplasia after balloon angioplasty. A study in the atherosclerotic rabbit.

    Science.gov (United States)

    Sarembock, I J; LaVeau, P J; Sigal, S L; Timms, I; Sussman, J; Haudenschild, C; Ezekowitz, M D

    1989-10-01

    To evaluate the effect of balloon size and inflation pressure on acute and subsequent outcome following balloon angioplasty (BA), 70 New Zealand White rabbits with bilateral femoral atherosclerosis were assigned to four groups: group 1, oversized balloon, low inflation pressure (n = 35 vessels; balloon size, 3.0 mm/inflation pressure, 5 atm); group 2, oversized balloon, high inflation pressure (n = 36; 3.0 mm/10 atm); group 3, appropriate size, low inflation pressure (n = 17; 2.5 mm/5 atm); and group 4, appropriate size balloon, high inflation pressure (n = 19; 2.5 mm/10 atm). Angiograms were obtained before, 10 minutes after, and 28 days after BA and read by two blinded observers using electronic calipers. The in vivo balloon-to-vessel ratio was measured for each group. There were eight non-BA controls. Rabbits were sacrificed either immediately (n = 34) or at 28 days after BA (n = 36), with the femoral vessels pressure perfused for histologic and morphometric analysis. The latter was performed at 28 days only. Absolute angiographic diameters increased in all groups immediately after BA (p less than 0.01). Acute angiographic success, defined as greater than 20% increase in luminal diameter, was higher using high inflation pressure (group 2, 32/36 [89%] and group 4, 16/19 [84%] vs. group 1, 23/35 [66%] and group 3, 9/17 [53%]; p less than 0.05). A 3.0-mm balloon resulted in significant oversizing irrespective of inflation pressure (balloon-to-vessel ratio, 1.5 +/- 0.1 vs. 1.1 +/- 0.1 to 1, for the 2.5-mm balloon). Vessels exposed to high inflation pressure had a significantly higher incidence of mural thrombus, dissection (p less than 0.01), and medial necrosis versus low pressure (p less than 0.05). At 28 days, the rates of restenosis (defined as greater than 50% loss of initial gain) were 14/20 (70%), 11/16 (69%), 5/10 (50%), and 5/10 (50%) for groups 1 through 4 (p = NS; a trend in favor of the groups using an oversized balloon). There was an increase in the

  8. Cephalic arch stenosis in autogenous brachiocephalic hemodialysis fistulas: results of cutting balloon angioplasty

    DEFF Research Database (Denmark)

    Heerwagen, Søren Thorup; Lönn, Lars; Schroeder, Torben V;

    2010-01-01

    Cephalic arch stenosis is a known cause of hemodialysis access failure in patients with brachiocephalic fistulas (BCFs). Outcomes of endovascular treatment are affected by resistance of the stenosis to balloon dilation, a high vein rupture rate and the development of early restenosis. The purpose...... of this retrospective study was to report outcomes after cutting balloon angioplasty (CBA) of cephalic arch stenosis....

  9. Residual stenosis after conventional balloon angioplasty for hemodialysis shunt failure: treatment with metallic stent placement and post-balloon dilatation.

    Science.gov (United States)

    Kariya, Shuji; Tanigawa, Noboru; Kojima, Hiroyuki; Komemushi, Atsushi; Shiraishi, Tomokuni; Kawanaka, Toshiaki; Sawada, Satoshi

    2005-02-01

    The usefulness of metallic stent placement and post-balloon dilatation was investigated for patients with residual stenosis after conventional percutaneous transluminal balloon angioplasty (balloon PTA) of dialysis shunt vessels. Among 92 patients who had received balloon PTA for dialysis shunt vessels, seven patients who showed a residual waist on the balloon even under maximum inflation were enrolled in this study. In these patients with residual stenosis after balloon PTA, we inserted a stent in the residual stenosis, and post-balloon dilatation was immediately applied using the same balloon catheter. After balloon PTA, the average percent diameter stenosis declined to 45.5 +/- 7.30%, and the stenosis was further improved to an average of 19.3 +/- 7.09% after the placement of a stent and the additional balloon PTA. The average percent diameter dilatation of the balloon before the placement of a stent was 65.8 +/- 12.7%, while the average dilatation increased to 84.1 +/- 8.96% after the placement of a stent. Dialysis became possible immediately after the procedure in all cases. Metallic stent placement and post-balloon dilatation was effective for patients with residual stenosis after conventional balloon PTA of dialysis shunt vessels.

  10. Healing after arterial dilatation with radiofrequency thermal and nonthermal balloon angioplasty systems.

    Science.gov (United States)

    Kaplan, J; Barry, K J; Connolly, R J; Nardella, P C; Hayes, L L; Lee, B I; Waller, B F; Becker, G J; Callow, A D

    1993-01-01

    Thermal balloon angioplasty has been proposed as a means of reducing acute and delayed reclosure of arteries after percutaneous transluminal balloon angioplasty. A radiofrequency (rf) balloon catheter was used to perform thermal balloon angioplasty on canine arteries in vivo. The histologic appearance of rf-treated sites was compared with that of control sites treated by conventional percutaneous transluminal angioplasty. Acutely, rf-treated sites showed a reduced medial cellularity with preservation of internal elastic lamina except at the transitional zone between thermal injury and normal artery, where localized internal elastic lamina disruption was found. Nonthermal sites showed generalized disruption of internal elastic lamina and normal medial cellularity. Both thermal and nonthermal sites displayed a return of intimal cover commencing at 1 to 2 weeks and completed by 4 weeks. Diffuse myointimal hyperplasia appeared by 2 weeks after injury at breaks in the internal elastic lamina along the nonthermal vessels but was localized to the transitional zone in thermal injury sites. In rf-treated vessels, repopulation of the acellular thermally modified media had commenced by 4 weeks, and by 8 weeks the media was diffusely repopulated by spindle-shaped cells resembling smooth muscle cells lying between and aligned with preserved connective tissue laminae. Overall, the distribution and extent of the proliferative response after rf thermal balloon angioplasty were less than those seen after nonthermal balloon angioplasty. Thermal sites, which underwent reintimalization before medial cells returned, were considerably less prone to the development of myointimal hyperplasia. These results suggest that this modality may have beneficial effects on arterial healing after angioplasty.

  11. A comparison of balloon-expandable-stent implantation with balloon angioplasty in patients with coronary artery disease

    NARCIS (Netherlands)

    P.W.J.C. Serruys (Patrick); P.P.T. de Jaegere (Peter); F. Kiemeneij (Ferdinand); C.M. Miguel (Carlos); W.R. Rutsch (Wolfgang); G.R. Heyndrickx (Guy); H.U. Emanuelsson (Hakan); J. Marco (Jean); V.M.G. Legrand (Victor); P.H. Materne (Phillipe); J.A. Belardi (Jorge); U. Sigwart (Ulrich); A. Colombo (Antonio); J-J. Goy (Jean-Jacques); P.A. van den Heuvel (Paul); J. Delcan; M-A.M. Morel (Marie-Angèle)

    1994-01-01

    textabstractBalloon-expandable coronary-artery stents were developed to prevent coronary restenosis after coronary angioplasty. These devices hold coronary vessels open at sites that have been dilated. However, it is unknown whether stenting improves long-term angiographic and clinical outcomes as c

  12. A comparison of balloon-expandable-stent implantation with balloon angioplasty in patients with coronary artery disease.

    NARCIS (Netherlands)

    P.W.J.C. Serruys (Patrick); P.P.T. de Jaegere (Peter); F. Kiemeneij (Ferdinand); C.M. Miguel (Carlos); W.R. Rutsch (Wolfgang); G.R. Heyndrickx (Guy); H.U. Emanuelsson (Hakan); J. Marco (Jean); V.M.G. Legrand (Victor); P.H. Materne (Phillipe); J.A. Belardi (Jorge); U. Sigwart (Ulrich); A. Colombo (Antonio); J-J. Goy (Jean-Jacques); P. van den Heuvel; J. Delcan; M-A.M. Morel (Marie-Angèle)

    1994-01-01

    textabstractBACKGROUND. Balloon-expandable coronary-artery stents were developed to prevent coronary restenosis after coronary angioplasty. These devices hold coronary vessels open at sites that have been dilated. However, it is unknown whether stenting improves long-term angiographic and clinical o

  13. Comparison of a nitinol stent versus balloon angioplasty for treatment of a dysfunctional arteriovenous graft

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, Yeo Chang; Shin, Byung Seok; Ahn, Moon Sang [Chungnam National University Hospital, Daejeon (Korea, Republic of); Park, Mi Hyun [Dankook Univ. Hospital, Cheonan (Korea, Republic of); Ohm, Joon Young [The Catholic Univ. of Korea College of Medicine/Bucheon St. Mary' s Hospital, Bucheon (Korea, Republic of); Kim, Ho Jun [Konyang Univ. Hospital, Daejeon (Korea, Republic of)

    2012-06-15

    This study aimed to 1) evaluate the outcome of placing a nitinol stent for treating dysfunctional arteriovenous grafts (AVG), and 2) compare the results with those of successful balloon angioplasty. Between February 2008 and October 2011, we retrospectively reviewed the interventional data and medical records of 29 patients (21 men, 8 women; mean age, 67.4 years) who underwent interventional procedures for dysfunctional AVG. Stents were placed only in cases with inadequate angioplasty results. Stent patency was evaluated and compared to cases of successful balloon angioplasty using the Kaplan Meier analysis. Eleven stents and 18 angioplasties were performed successfully at the venous anastomotic site of AVG. The primary patency at 3, 6, 12, and 18 months did not differ significantly for stent placement and angioplasty (52%, 29%, 15%, 15% vs. 71%, 50%, 34%, 34%; mean survival, 164 vs. 253 days, p = 0.283). Secondary patency of the stent also did not differ significantly from angioplasty (80%, 80%, 49%, 49% vs. 76%, 57%, 57%, 36%; mean survival, 405 vs. 385 days, p = 0.553). Nitinol stent placement was effective for treating dysfunctional AVG, but did not improve the primary and secondary patency compared to successful angioplasty.

  14. Cutting balloon angioplasty for undilatable venous stenoses causing dialysis graft failure.

    Science.gov (United States)

    Bittl, John A; Feldman, Robert L

    2003-04-01

    Dialysis fistulas and bridge grafts frequently develop outflow stenoses in the venous limb, leading to graft failure. The venous stenoses are fibrotic and require percutaneous transluminal angioplasty with high-pressure balloons. We have encountered venous stenoses in 3 out of 219 hemodialysis patients with graft failure that were undilatable with 6-8 mm high-pressure balloons inflated to more than 24 atm. In each of these cases, treatment with a 4 mm cutting balloon successfully facilitated subsequent balloon dilation at lower pressures. Copyright 2003 Wiley-Liss, Inc.

  15. Effect of low-grade conductive heating on vascular compliance during in vitro balloon angioplasty.

    Science.gov (United States)

    Mitchel, J F; Fram, D B; Aretz, T A; Gillam, L D; Woronick, C; Waters, D D; McKay, R G

    1994-07-01

    Radiofrequency-powered, thermal balloon angioplasty is a new technique that enhances luminal dilatation with less dissection than conventional angioplasty. The purpose of this study was to assess the effect of radiofrequency heating of balloon fluid on the pressure-volume mechanics of in vitro balloon angioplasty and to determine the histologic basis for thermal-induced compliance changes. In vitro, radiofrequency-powered, thermal balloon angioplasty was performed on 46 paired iliac segments freshly harvested from 23 nonatherosclerotic pigs. Balloon inflations at 60 degrees C were compared to room temperature inflations in paired arterial segments. Intraballoon pressure and volume were recorded during each inflation as volume infusion increased pressure over a 0 to 10 atm range. Pressure-volume compliance curves were plotted for all dilatations. Six segments were stained to assess the histologic abnormalities associated with thermal compliance changes. Radiofrequency heating acutely shifted the pressure-volume curves rightward in 20 of 23 iliac segments compared to nonheated controls. This increase in compliance persisted after heating and exceeded the maximum compliance shift caused by multiple nonheated inflations in a subset of arterial segments. Histologically, heated segments showed increased thinning and compression of the arterial wall, increased medial cell necrosis and altered elastic tissue fibers compared to nonheated specimens. In conclusion, radiofrequency heating of intraballoon fluid to 60 degrees C acutely increases vascular compliance during in vitro balloon angioplasty of nonatherosclerotic iliac arteries. The increased compliance persists after heating and can be greater than the compliance shifts induced by multiple conventional dilatations. Arterial wall thinning and irreversible alteration of elastic tissue fibers probably account for thermal compliance changes.

  16. Cost-effectiveness analysis of orbital atherectomy plus balloon angioplasty vs balloon angioplasty alone in subjects with calcified femoropopliteal lesions

    Directory of Open Access Journals (Sweden)

    Weinstock B

    2014-03-01

    Full Text Available Barry Weinstock,1 Raymond Dattilo,2 Tiffini Diage3 1Orlando Health Heart Institute, Mid-Florida Cardiology Specialists, Orlando, FL, USA; 2Department of Cardiology, St Francis Health Center, Topeka, KS, USA; 3North American Science Association (NAMSA, Sunnyvale, CA, USA Introduction: As cost considerations become increasingly critical when selecting optimal endovascular treatment strategies, a cost-benefit analysis was conducted comparing the Diamondback 360°® Orbital Atherectomy System (OAS (Cardiovascular Systems, Inc., St Paul, MN, USA and balloon angioplasty (BA vs BA alone for treatment of calcified femoropopliteal lesions. Patients and methods: The clinical outcomes from COMPLIANCE 360°, a prospective, multicenter, randomized study comparing OAS+BA vs BA alone for treatment of calcified femoropopliteal lesions, were correlated with cost data and previously published quality of life data. Site of service, hospital charges, and associated medical resource utilization were obtained from Uniform Billing statements for index treatments and associated revascularizations out to 1 year. Hospital costs were estimated using hospital-specific, procedure-specific cost-to-charge ratios. Length of stay and procedural data were collected from participating study sites. Results: Twenty-five subjects with 38 lesions and 25 subjects with 27 lesions were randomized to the OAS+BA and BA-alone groups, respectively. Mean hospital charges (US$51,755 vs US$39,922 and estimated hospital costs (US$15,100 vs US$11,016 were higher for OAS+BA compared with BA alone (not statistically significant. Stent utilization was statistically significantly higher with BA-alone treatment for all subjects (1.1 vs 0.1, P=0.001 and in the subset of subjects with one lesion (1.0 vs 0.1, P<0.00001. There was a significant difference in cost for single-lesion versus multiple-lesion treatment. Using costs and quality-adjusted life years (QALYs for the single-lesion cohort, the 1-year

  17. Angiographic risk factors of luminal narrowing after coronary balloon angioplasty using balloon measurements to reflect stretch and elastic recoil at the dilation site. The CARPORT Study Group

    NARCIS (Netherlands)

    B.J.W.M. Rensing (Benno); W.R.M. Hermans (Walter); J. Vos (Jeroen); K.J. Beatt (Kevin); P.M.M. Bossuyt (Patrick); W.R. Rutsch (Wolfgang); P.W.J.C. Serruys (Patrick)

    1992-01-01

    textabstractBecause many ongoing clinical restenosis prevention trials are using quantitative angiography to assess whether a drug is capable of reducing the amount of intimal hyperplasia, quantitative angiographic risk factors for angiographic luminal narrowing after balloon angioplasty were determ

  18. Angiographic risk factors of luminal narrowing after coronary balloon angioplasty using balloon measurements to reflect stretch and elastic recoil at the dilatation site

    NARCIS (Netherlands)

    B.J.W.M. Rensing (Benno); W.R.M. Hermans (Walter); J. Vos (Jeroen); K.J. Beatt (Kevin); P.M.M. Bossuyt (Patrick); W.R. Rutsch (Wolfgang); P.W.J.C. Serruys (Patrick)

    1992-01-01

    textabstractAbstract Because many ongoing clinical restenosis prevention trials are using quantitative angiography to assess whether a drug is capable of reducing the amount of intimal hyperplasia, quantitative angiographic risk factors for angiographic luminal narrowing after balloon angioplasty

  19. Balloon Angioplasty - The Legacy of Andreas Grüntzig, M.D. (1939-1985

    Directory of Open Access Journals (Sweden)

    Matthias eBarton, MD, FAHA

    2014-12-01

    Full Text Available In 1974, at the Medical Policlinic of the University of Zürich, German-born physician-scientist Andreas Grüntzig (1939-1985 successfully applied a balloon-tipped catheter to re-open a severely stenosed femoral artery, a procedure which he initially called percutaneous transluminal dilatation. Transluminal angioplasty of atherosclerotic vascular disease, for which Grüntzig and Charles T. Dotter (1920-1985 received a nomination for the Nobel Prize in Physiology or Medicine in 1978, became one of the most successful examples of translational medicine in the 20th century. Known today as percutaneous transluminal angioplasty (PTA in peripheral arteries or percutaneous transluminal coronary angioplasty (PTCA or percutaneous coronary intervention (PCI in coronary arteries, balloon angioplasty has become the method of choice to treat patients with acute myocardial infarction or occluded leg arteries. On the occasion of the 40th anniversary of balloon angioplasty, we summarize Grüntzig’s life and career in Germany, Switzerland, and the United States and also review the developments in vascular medicine from the 1890s to the 1980s, including Dotter’s first accidental angioplasty in 1963. The work of pioneers of catheterization, including Pedro L. Fariñas in Cuba, André F. Cournand in France, Werner Forssmann, Werner Porstmann and Eberhard Zeitler in Germany, Sven-Ivar Seldinger in Sweden, and Thomas J. Fogarty, Melvin P. Judkins, Richard K. Myler, Dickinson W. Richards, and F. Mason Sones in the United States, is discussed. We also present quotes and excerpts from a unfinished book manuscript by Grüntzig, statements of his former colleagues and contemporary witnesses, and also include hitherto unpublished historic photographs and links to historic materials and archive recordings. This year, on June 25, 2014, Andreas Grüntzig would have celebrated his 75th birthday. This article is dedicated to his memory.

  20. Cutting-Balloon Angioplasty Versus Balloon Angioplasty as Treatment for Short Atherosclerotic Lesions in the Superficial Femoral Artery: Randomized Controlled Trial

    Energy Technology Data Exchange (ETDEWEB)

    Poncyljusz, Wojciech, E-mail: wponcyl@poczta.onet.pl; Falkowski, Aleksander, E-mail: bakhis@hot.pl [Pomeranian Medical University, Department of Interventional Radiology (Poland); Safranow, Krzysztof, E-mail: chrissaf@mp.pl; Rac, Monika, E-mail: carmon@pum.edu.pl [Pomeranian Medical University, Department of Biochemistry and Medical Chemistry (Poland); Zawierucha, Dariusz, E-mail: dariusz13@yahoo.com [Interventional Radiology, Sacred Heart Medical Center, River Bend (United States)

    2013-12-15

    Purpose: To evaluate the treatments of a short-segment atherosclerotic stenosis in the superficial femoral arteries with the cutting balloon angioplasty (CBA) versus conventional balloon angioplasty [percutaneous transluminal angioplasty (PTA)] in a randomized controlled trial. Material and Methods: The study group comprised 60 patients (33 men, 27 women; average age 64 years) with a short ({<=}5 cm) focal SFA de novo atherosclerotic stenosis associated with a history of intermittent claudication or rest pain. The primary end point of this study was the rate of binary restenosis in the treated segment 12 months after the intervention. All patients were evenly randomized to either the PTA or CBA treatment arms. Follow-up angiograms and ankle-brachial index (ABI) measurements were performed after 12 months. The evaluation of the restenosis rates and factors influencing its occurrence were calculated by logistic regression analysis. Results: In the intention-to-treat analysis, restenosis rates after 2-month follow-up were 9 of 30 (30 %) in the PTA group and 4 of 30 (13 %) in the CBA group (p = 0.117). In the actual treatment analysis, after exclusion of patients who required nitinol stent placement for a suboptimal result after angioplasty alone (5 patients in the PTA group and none in the CBA group), restenosis rates were 9 of 25 (36 %) and 4 of 30 (13 %), respectively (p = 0.049). In the intention-to-treat analysis there were also significant differences in ABI values between the PTA and CBA groups at 0.77 {+-} 0.11 versus 0.82 {+-} 0.12, respectively (p = 0.039), at 12 months. Conclusion: Based on the presented results of the trial, CBA seems to be a safer and more effective than PTA for treatment of short atherosclerotic lesions in the superior femoral artery.

  1. Usefulness of repeat coronary angiography 24 hours after balloon angioplasty to evaluate early lminal deterioration and facilitate quantitative analysis

    NARCIS (Netherlands)

    G.R. Heyndrickx (Guy); G-J. Laarman (GertJan); H. Suryapranata (Harry); F. Zijlstra (Felix); P.W.J.C. Serruys (Patrick); D.P. Foley (David); A.A. van den Bos (Arjan); J.W. Deckers (Jaap)

    1993-01-01

    textabstractBecause of the unavoidable occurrence of vessel disruption after successful coronary balloon angioplasty, the reliability of quantitative angiographic analysis in that setting has been questioned. For this reason and the suggested occurrence of delayed elastic recoil, repeat angiography

  2. Cutting balloon angioplasty for resistant venous stenoses of dialysis access: immediate and patency results.

    Science.gov (United States)

    Wu, Chih-Cheng; Wen, Szu-Chi

    2008-02-01

    To evaluate the technical success, safety and patency of cutting balloon angioplasty for the treatment of resistant dialysis access stenoses. Cutting balloon angioplasty has been proposed to be useful in treating resistant dialysis access stenoses. However, they are based on experience with very limited cases and formal patency data is insufficient. The author retrospectively reviewed 896 percutaneous transluminal angioplasty (PTA) procedures for the treatment of dysfunctional or thrombotic dialysis access. Thirty-seven of 623 patients with native fistulas and 23 of 273 patients with synthetic grafts had residual stenoses of more than 30% after conventional PTA at an inflation pressure of 24 atm for 60 sec. In these 60 patients, additional cutting balloon PTA was performed. The overall technical success rate was 96.7% and clinical success rate was 98.3%. Only one patient experienced mild local extravasation. The postintervention primary patency rates for native fistula group (N = 37) were 100%, 86.4%, and 67.5% at 1-month, 3-month, and 6-month; the postintervention primary patency rates for synthetic graft group (N = 23) were 87.0%, 60.9%, and 34.2% at 1-month, 3-month, and 6-month respectively. For resistant venous stenoses of dialysis access, cutting balloon PTA is effective, safe, and seems to provide comparative primary patency as suggested by guidelines. Copyright 2008 Wiley-Liss, Inc.

  3. Optical coherence tomography layer thickness characterization of a mock artery during angioplasty balloon deployment

    Science.gov (United States)

    Azarnoush, Hamed; Vergnole, Sébastien; Boulet, Benoît; Lamouche, Guy

    2011-03-01

    Optical coherence tomography (OCT) is used to study the deformation of a mock artery in an angioplasty simulation setup. An OCT probe integrated in a balloon catheter provides intraluminal real-time images during balloon inflation. Swept-source OCT is used for imaging. A 4 mm semi-compliant polyurethane balloon is used for experiments. The balloon is inflated inside a custom-built multi-layer artery phantom. The phantom has three layers to mock artery layers, namely, intima, media and adventitia. Semi-automatic segmentation of phantom layers is performed to provide a detailed assessment of the phantom deformation at various inflation pressures. Characterization of luminal diameter and thickness of different layers of the mock artery is provided for various inflation pressures.

  4. Ureteric angioplasty balloon placement to increase localised dosage of BCG for renal pelvis TCC.

    LENUS (Irish Health Repository)

    Forde, J C

    2012-03-01

    Endoscopic percutaneous resection of a renal pelvis transitional cell carcinoma (TCC) is a viable treatment option in those who would be rendered dialysis dependent following a nephroureterectomy. We report endoscopic percutaneous resection of an upper tract TCC recurrence in a single functioning kidney followed by antegrade renal pelvis BCG instillation with novel placement of inflated angioplasty balloon in the ureter to help localise its effect.

  5. Balloon angioplasty for disruption of tunneled dialysis catheter fibrin sheath.

    Science.gov (United States)

    Watorek, Ewa; Golebiowski, Tomasz; Letachowicz, Krzysztof; Garcarek, Jerzy; Kurcz, Jacek; Bartosik, Hanna Augustyniak; Letachowicz, Waldemar; Weyde, Waclaw; Klinger, Marian

    2012-01-01

    Management of failing tunneled hemodialysis catheters, sometimes the only vascular access for hemodialysis, presents a difficult problem. In spite of various techniques having been developed, no consensus has been reached about the preferred technique, associated with the longest catheter patency. We report disruption of the fibrin sheath covering dysfunctional tunneled hemodialysis catheter by means of angioplasty, followed by over guidewire catheter exchange. Following the procedure, the catheter placed in the recovered lumen of the vessel presented correct function. The described procedure allowed maintenance of vascular access in our patient. Additionally, dilatation of the concomitant central vein stenosis opens an option for another attempt for arteriovenous fistula creation.

  6. Intraoperative balloon angioplasty using fogarty artertial embolectomy balloon catheter for creation of arteriovenous fistula for hemodialysis: single center experience.

    Science.gov (United States)

    Jin, Moran; Yoon, Young Chul; Wi, Jin Hong; Lee, Yang-Haeng; Han, Il-Yong; Park, Kyung-Taek

    2015-04-01

    The purpose of this study was to evaluate the use of a Fogarty arterial embolectomy catheter (Fogarty catheter) in intraoperative balloon angioplasty of the cephalic vein, in order to determine its effect on the patency of arteriovenous fistulas (AVFs) created for hemodialysis access. A total of 156 patients who underwent creation of an AVF were divided into two groups, based whether a Fogarty catheter was used during AVF creation. Group A (89 patients) comprised the patients who underwent balloon angioplasty with a Fogarty catheter during the operation. Group B (67 patients) included the patients in whom a Fogarty catheter was not used during the operation. Patient records were reviewed retrospectively and documented. The patency rate was determined by the Kaplan-Meier method. The records of 156 patients who underwent the creation of an AVF from January 2007 to October 2011 were included. The mean follow-up duration was 40.2±19.4 months (range, 1 to 97 months). The patency rates in group A at 12, 36, and 72 months were 83.9%±3.9%, 78.3%±4.6%, and 76.3%±4.9%, respectively, while the corresponding patency rates in group B were 92.5%±3.2%, 82.8%±0.5%, and 79.9%±5.7%, respectively. The patency rates in group B were found to be slightly higher than those in group A, but the difference was not statistically significant (p=0.356). Intraoperative balloon angioplasty of the cephalic vein using the Fogarty catheter is a simple and easily reproducible procedure, and it can be helpful in increasing AVF patency in cases of insufficient runoff or a suboptimal cephalic vein.

  7. Utility of birefringence changes due to collagen thermal denaturation rate process analysis: vessel wall temperature estimation for new short term heating balloon angioplasty

    Science.gov (United States)

    Kaneko, Kenji; Shimazaki, Natsumi; Gotoh, Maya; Nakatani, Eriko; Arai, Tsunenori

    2007-02-01

    Our photo thermal reaction heating architecture balloon realizes less than 10 s short term heating that can soften vessel wall collagen without damaging surrounding tissue thermally. New thermal balloon angioplasty, photo-thermo dynamic balloon angioplasty (PTDBA) has experimentally shown sufficient opening with 2 atm low pressure dilation and prevention of chronic phase restenosis and acute phase thrombus in vivo. Even though PTDBA has high therapeutic potential, the most efficient heating condition is still under study, because relationship of treatment and thermal dose to vessel wall is not clarified yet. To study and set the most efficient heating condition, we have been working on establishment of temperature history estimation method from our previous experimental results. Heating target of PTDBA, collagen, thermally denatures following rate process. Denaturation is able to be quantified with measured collagen birefringence value. To express the denaturation with equation of rate process, the following ex vivo experiments were performed. Porcine extracted carotid artery was soaked in two different temperature saline baths to enforce constant temperature heating. Higher temperature bath was set to 40 to 80 degree Celsius and soaking duration was 5 to 40 s. Samples were observed by a polarizing microscope and a scanning electron microscope. The birefringence was measured by polarizing microscopic system using Brace-Koehler compensator 1/30 wavelength. The measured birefringence showed temperature dependency and quite fit with the rate process equation. We think vessel wall temperature is able to be estimated using the birefringence changes due to thermal denaturation.

  8. Angioplasty and stent - heart - discharge

    Science.gov (United States)

    Drug-eluting stents - discharge; PCI - discharge; Percutaneous coronary intervention - discharge; Balloon angioplasty - discharge; Coronary angioplasty - discharge; Coronary artery angioplasty - discharge; Cardiac ...

  9. High versus low-pressure balloon inflation during multilinktrade mark stent implantation: acute and long-term angiographic results.

    Science.gov (United States)

    Caixeta, A M; Brito, F S; Rati, M; Perin, M A; da Luz, P L; Ramires, J A; Ambrose, J A; Martinez, E E

    2000-08-01

    We compared the impact of low and high-pressure balloon inflation on acute and late angiographic results of Multilink stent. Low-pressure balloon inflation (9.5 +/- 1.9 atm) was used in 43 stents and high pressure (17.1 +/- 1.5 atm) in 44. A larger immediate luminal gain was achieved in stents with high-pressure balloon inflation (1.80 +/- 0.26 vs. 1.47 +/- 0.62; P = 0.002), resulting in a larger mean diameter in this group (2.71 +/- 0.37 vs. 2.48 +/- 0.47; P = 0.017). At follow-up, a larger luminal diameter was achieved in the high pressure group (1.93 +/- 0.72 vs. 1.45 +/- 0.66; P = 0.002) and a trend to a lower rate of angiographic restenosis (15% vs. 38%, P = 0.08).

  10. Cineangiographic findings and balloon catheter angioplasty of pulmonic valvular stenosis

    Energy Technology Data Exchange (ETDEWEB)

    Yeon, Kyung Mo; Yoon, Yong Soo; Kim, In One; Han, Man Chung [College of Medicine, Seoul National University, Seoul (Korea, Republic of)

    1987-08-15

    Transluminal balloon valvuloplasty was performed in the treatment of congenital pulmonic valvular stenosis in 55 children, aged 4 months to 15 years. The right ventricular outflow tract pressure gradient decreased significantly immediately after the procedure from 87.18 {+-} 56mmHg to 29.62 {+-} 26.48mmHg ({rho} < 0.001). Technical success rate was 98% (54/55 patients) and failed case (1 patient) was due to severe fibrous thickening of valve. Complication occurred in one case, that is tricuspid regurgitation (Grade II) due to suspected rupture of chordae tendinae. The degree of pulmonary conus dilatation was closely related with age than the pressure gradient.

  11. Infrapopliteal Percutaneous Transluminal Balloon Angioplasty: Clinical Results and Influence Factors

    Energy Technology Data Exchange (ETDEWEB)

    Song, Jang Hyeon; Lee, Seung Jin; Jung, Hye Doo; Lim, Jae Hoon; Chang, Nam Kyu; Yim, Nam Yeol; Kim, Jae Kyu [Dept. of Radiology, Chonnam National University Hospital, Gwangju (Korea, Republic of); Lee, Keun Bae [Dept. of Radiology, Chonnam National University Hospital, Gwangju (Korea, Republic of)

    2011-09-15

    To assess the efficacy of percutaneous transluminal angioplasty (PTA) in patients with infrapopliteal arterial disease, and to determine the influencing factor for prognosis. A total of 55 patients (60 limbs) with infrapopliteal arterial stenosis or occlusion underwent PTA. Atherosclerotic risk factors, clinical symptoms, TransAtlantic Inter-Society Consensus (TASC) classification, and vascular wall calcification were evaluated before PTA. The number of patent infrapopliteal arteries was estimated, and the outcome was evaluated by symptom relief and limb salvage. Technical success was achieved in 53/60 limbs (88.3%) and 81/93 arteries (87.1%), TASC classification (p = 0.038) and vascular calcification (p = 0.002) influenced on technical failure. During follow-up, 26 of 55 limbs (47%) achieved symptom relief and 42/55 limbs (76%) underwent limb salvage. Non-diabetic patients (9/12, 75%) were superior to diabetic patients (17/43, 40%) in terms of symptom relief (p = 0.024). TASC classification and vascular wall calcification influenced on symptom relief and limb salvage. The number of patent infrapopliteal arteries after PTA influenced symptom relief (p < 0.001) and limb amputation (p = 0.003). PTA in patients with chronic critical limb ischemia is worthwhile as a primary treatment. The influence factors should be considered before PTA, and PTA should be performed in as many involved arteries as possible.

  12. Detection of platelet deposition at the site of peripheral balloon angioplasty using indium-111 platelet scintigraphy

    Energy Technology Data Exchange (ETDEWEB)

    Pope, C.F.; Ezekowitz, M.D.; Smith, E.O.; Rapoport, S.; Glickman, M.; Sostman, H.D.; Zaret, B.L.

    1985-02-01

    Restenosis after balloon angioplasty may be mediated through platelet deposition at the site of arterial dilatation. The purpose of this study was to determine whether platelet deposition at the site of dilatation could be detected using indium-111 platelet scintigraphy. Fifteen patients, aged 60 +/- 9 years, with iliac or femoral (n . 12), renal artery (n . 2) or distal aortic (n . 1) stenoses were studied. All patients received intravenous heparin at the time of dilatation. Labeled platelets containing 471 +/- 65 muCi indium-111 were injected 0.25 to 4 hours after dilatation and 1 to 24 hours after imaging. In 11 of 12 patients with iliac and femoral dilatations, focal uptake was demonstrated at the angioplasty site. In 4 patients (2 patients with renal, 1 patient with iliofemoral, and 1 with distal aortic stenoses), uptake at the dilatation sites was not detected. This preliminary study indicates that despite intravenous heparin, platelets accumulate at sites of balloon dilatation. Platelet scintigraphy may be useful in predicting sites of future narrowing after angioplasty and may be used to test the efficacy of antiplatelet therapy in retarding restenosis.

  13. Balloon pulmonary angioplasty: a treatment option for inoperable patients with chronic thromboembolic pulmonary hypertension

    Directory of Open Access Journals (Sweden)

    Aiko eOgawa

    2015-02-01

    Full Text Available In chronic thromboembolic pulmonary hypertension, stenoses or obstructions of the pulmonary arteries due to organized thrombi can cause an elevation in pulmonary artery resistance, which in turn can result in pulmonary hypertension. Chronic thromboembolic pulmonary hypertension can be cured surgically by pulmonary endarterectomy; however, patients deemed unsuitable for pulmonary endarterectomy due to lesion, advanced age, or comorbidities have a poor prognosis and limited treatment options. Recently, advances have been made in balloon pulmonary angioplasty for these patients, and this review highlights this recent progress.

  14. Self-expanding nitinol stents for treatment of infragenicular arteries following unsuccessful balloon angioplasty

    Energy Technology Data Exchange (ETDEWEB)

    Tepe, Gunnar; Heller, Stephan; Wiskirchen, Jakub; Fischmann, Arne; Claussen, Claus D. [University of Tuebingen, Department of Diagnostic Radiology, Tuebingen (Germany); Zeller, Thomas [Heart Center, Bad Krotzingen (Germany); Coerper, Stephan; Beckert, Stefan [University of Tuebingen, Department of Surgery, Tuebingen (Germany); Balletshofer, Bernd [University of Tuebingen, Department of Angiology, Tuebingen (Germany)

    2007-08-15

    The feasibility of self-expanding nitinol stents for treatment of infragenicular arteries following unsuccessful balloon angioplasty was assessed. Options for lower limb percutaneous revascularization are limited, especially for complex vessel obstruction. Depending on the lesion and the experience of the interventionalist, the failure rate of balloon angioplasty (PTA) ranges between 10 and 40%. Until recently, no self-expanding stent for the use in the infragenicular arteries was available. This is the first report of the results for 18 consecutive patients who received 4F sheath compatible self-expanding nitinol stents following unsuccessful PTA or early restenosis. Twenty-four stents were implanted in 21 lesions for various indications residual stenosis >50% due to heavy calcification, flow-limiting dissection, occluding thrombus resistant to thrombolyis, thrombaspiration, and PTA, and early restenosis after previous PTA. Stent implantation was feasible in all cases. No complications occurred. After the stent implantation, all primarily unsuccessful interventions could be transformed into successful procedures with no residual stenosis >30% in any case. After 6 {+-} 2 months, two of the 18 patients died, and 14 of the 16 remaining patients improved clinically. At follow-up, the patency could be assessed in 14 stented arteries. Three stents were occluded, one stent showed some neointimal hyperplasia (50-70% restenosis), the remaining ten stents showed no restenosis (0-30%). The use of self-expanding nitinol stents in tibioperoneal and popliteal arteries is a safe and feasible option for the treatment of unsuccessful PTA. The 6-months patency is high. (orig.)

  15. [Recanalization of the peripheral arteries by laser thermal balloon angioplasty. 2 years of clinical experience].

    Science.gov (United States)

    Riambau Alonso, V; Masotti Centol, M; Latorre Vilallonga, J; Viver Manresa, E; Crexells Figueres, C; Oriol Palou, A

    1991-01-01

    Laser angioplasty represents an attractive alternative to overcome the limitations of balloon angioplasty. We describe our results with laser thermal balloon angioplasty (LTBA) in the treatment of atherosclerosis obliterans in the lower limbs after two years clinical follow up. We also analyse the influence of lesion characteristics on immediate results. Thirty seven patients (34 men), whose mean age was 58 +/- 9 years, were included in this study. Occlusive arterial disease (Fontaine stage II-IV), with 39 significant haemodynamic arterial lesions were present in all of them. Ankle/brachial Doppler index was O,51 +/- 0,17. Eighteen lesions were located in the iliac area (13 stenoses 2,3 +/- 1 cm of length and 5 occlusions 4,2 +/- 3 cm) and 21 lesions in femoro-popliteal area (5 stenoses 2,6 +/- 2 cm and 16 occlusions 5,7 +/- 3 cm). A percutaneous procedure was used in 38 cases and only in one case a femoral dissection was necessary. The laser source was argon in 26 cases and Nd-YAG in 13. The overall immediate angiographic and clinical success was 85% (89% in iliac lesions and 81% in femoropopliteal lesions; 100% in stenoses and 70% in occlusions). The presence of occlusion (p less than 0,01) and/or calcium (p less than O,05) influenced negatively the immediate results. No major complications were observed. Seven (17%) minor complications occurred, but no emergency surgery was necessary. The ankle/brachial Doppler index after treatment was 0,82 +/- 0,21. Cumulative clinical patency was 91% for successfully treated patients after two years follow up. We conclude that LTBA represents an effective and less aggressive way to treat atherosclerosis obliterans.(ABSTRACT TRUNCATED AT 250 WORDS)

  16. Cost-effectiveness of paclitaxel-coated balloon angioplasty in patients with drug-eluting stent restenosis.

    Science.gov (United States)

    Dorenkamp, Marc; Boldt, Julia; Leber, Alexander W; Sohns, Christian; Roser, Mattias; Boldt, Leif-Hendrik; Haverkamp, Wilhelm; Bonaventura, Klaus

    2013-07-01

    The economic impact of drug-eluting stent (DES) in-stent restenosis (ISR) is substantial, highlighting the need for cost-effective treatment strategies. Compared to plain old balloon angioplasty (POBA) or repeat DES implantation, drug-coated balloon (DCB) angioplasty is a cost-effective therapy for DES-ISR. A Markov state-transition model was used to compare DCB angioplasty with POBA and repeat DES implantation. Model input parameters were obtained from the literature, and the cost analysis was conducted from a German healthcare payer's perspective. Extensive sensitivity analyses were performed. Initial procedure costs amounted to €3488 for DCB angioplasty and to €2782 for POBA. Over a 6-month time horizon, the DCB strategy was less costly (€4028 vs €4169) and more effective in terms of life-years (LYs) gained (0.497 versus 0.489) than POBA. The DES strategy incurred initial costs of €3167 and resulted in 0.494 LYs gained, at total costs of €4101 after a 6-month follow-up. Thus, DCB angioplasty was the least costly and most effective strategy. Base-case results were influenced mostly by initial procedure costs, target lesion revascularization rates, and the costs of dual antiplatelet therapy. DCB angioplasty is a cost-effective treatment option for coronary DES-ISR. The higher initial costs of the DCB strategy compared to POBA or repeat DES implantation are offset by later cost savings. © 2013 Wiley Periodicals, Inc.

  17. Association between disruption of fibrin sheaths using percutaneous transluminal angioplasty balloons and late onset of central venous stenosis.

    Science.gov (United States)

    Ni, Nina; Mojibian, Hamid; Pollak, Jeffrey; Tal, Michael

    2011-02-01

    To compare the rates of central venous stenosis in patients undergoing hemodialysis who underwent disruption of fibrin sheath with percutaneous transluminal angioplasty balloons and those who underwent over-the-wire catheter exchange. This study is a retrospective review of 209 percutaneous transluminal angioplasty balloon disruption and 1304 over-the-wire catheter exchange procedures performed in 753 patients. Approval from the Human Investigations Committee was obtained for this study. Up to 10-year follow-up was performed. A χ(2) test was used to compare the rates of central venous stenosis after balloon disruption versus catheter exchange. A t-test was used to compare time to central venous stenosis development. Of the 753 patients in the study, 127 patients underwent balloon disruption of fibrin sheath and 626 had catheter exchange. Within the balloon disruption group, 18 (14.2%) of 127 patients subsequently developed central venous stenosis, compared with 44 (7.0%) of 626 in the catheter exchange group (P balloon disruption group had four or more subsequent catheter exchanges, versus 12.6% in the catheter exchange group (P balloon disruption of fibrin sheath and late-onset central venous stenosis. Because venography was not routinely performed in catheter exchange patients, future randomized studies are necessary to confirm these findings.

  18. A randomized comparison of balloon angioplasty versus rotational atherectomy in complex coronary lesions (COBRA study).

    Science.gov (United States)

    Dill, T; Dietz, U; Hamm, C W; Küchler, R; Rupprecht, H J; Haude, M; Cyran, J; Ozbek, C; Kuck, K H; Berger, J; Erbel, R

    2000-11-01

    Rotablation is a widely used technique for the treatment of complex coronary artery lesions but is so far only poorly supported by controlled studies. The Comparison of Balloon-Angioplasty versus Rotational Atherectomy study (COBRA) is a multicentre, prospective, randomized trial to compare short- and long-term effects of percutaneous transluminal coronary angioplasty (PTCA) and rotablation in patients with angiographically pre-defined complex coronary artery lesions. At seven clinical sites 502 patients with pre-defined complex coronary artery lesions were assigned to either PTCA (n=250) or rotablation (n=252). Primary end-points were procedural success, 6-month restenosis rates in the treated segments, and major cardiac events during follow-up. Procedural success was achieved in 78% (PTCA), and 85% (rotablation) (P=0.038) of cases. Crossover from PTCA to rotablation was 4% and 10% vice versa (P=0.019). There was no difference between PTCA and rotablation with respect to procedure-related complications such as Q wave infarctions (2.4% each), emergency bypass surgery (1.2% versus 2.4%), and death (1.6% versus 0.4%). However, more stents were required after PTCA (14.9% versus 6.4%, P<0.002), predominantly for bailout or unsatisfactory results. Including bail-out stents as an end-point, the procedural success rates were 73% for angioplasty and 84% for rotablation (P=0.006). At 6 months, symptomatic outcome, target vessel reinterventions and restenosis rates (PTCA 51% versus rotablation 49%, P=0.33) were not different. Complex coronary artery lesions can be treated with a high level of success and low complication rates either by PTCA with adjunctive stenting or rotablation. The long-term clinical and angiographic outcome is comparable.

  19. Critical appraisal of paclitaxel balloon angioplasty for femoral–popliteal arterial disease

    Directory of Open Access Journals (Sweden)

    Herten M

    2016-08-01

    Full Text Available Monika Herten,1 Giovanni B Torsello,1,2 Eva Schönefeld,3 Stefan Stahlhoff2 1Department of Vascular and Endovascular Surgery, University Hospital Münster, 2Department of Vascular Surgery, St Franziskus Hospital, Münster, 3Institute for Education and Student Affairs, University Hospital Münster, Münster, Germany Abstract: Peripheral arterial disease, particularly critical limb ischemia, is an area with urgent need for optimized therapies because, to date, vascular interventions often have limited life spans. In spite of initial encouraging technical success after femoropopliteal percutaneous transluminal angioplasty or stenting, postprocedural restenosis remains the major problem. The challenging idea behind the drug-coated balloon (DCB concept is the biological modification of the injury response after balloon dilatation. Antiproliferative drugs administered via DCBs or drug-eluting stents are able to suppress neointimal hyperplasia, the main cause of restenosis. This article reviews the results of DCB treatments of femoropopliteal and infrapopliteal lesions in comparison to standard angioplasty with uncoated balloons. A systematic literature search was performed in 1 medical journals (ie, MEDLINE, 2 international registers for clinical studies (ie, www.clinicaltrials.gov, and 3 abstracts of scientific sessions. Several controlled randomized trials with follow-up periods of up to 5 years demonstrated the efficacy of paclitaxel –DCB technology. However, calcified lesions seem to affect the efficacy of DCB. Combinations of preconditioning methods with DCBs showed promising results. Although the mechanical abrasion of calcium via atherectomy or laser ablation showed favorable periprocedural results, the long-term impact on restenosis and clinical outcome has to be demonstrated. Major advantages of the DCBs are the rapid delivery of drug at uniform concentrations with a single dose, their efficacy in areas wherein stents have been

  20. Preliminary experience with drug-coated balloon angioplasty in primary percutaneous coronary intervention

    Institute of Scientific and Technical Information of China (English)

    Hee; Hwa; Ho; Julian; Tan; Yau; Wei; Ooi; Kwok; Kong; Loh; Than; Htike; Aung; Nwe; Tun; Yin; Dasdo; Antonius; Sinaga; Fahim; Haider; Jafary; Paul; Jau; Lueng; Ong

    2015-01-01

    We evaluated the clinical feasibility of using drugcoated balloon(DCB) angioplasty in patients undergoingprimary percutaneous coronary intervention(PPCI). Between January 2010 to September 2014,89 STelevation myocardial infarction patients(83% male,mean age 59 ± 14 years) with a total of 89 coronary lesions were treated with DCB during PPCI. Clinical outcomes are reported at 30 d follow-up. Left anterior descending artery was the most common target vessel for PCI(37%). Twenty-eight percent of the patients had underlying diabetes mellitus. Mean left ventricular ejection fraction was 44% ± 11%. DCB-only PCI was the predominant approach(96%) with the remaining 4% of patients receiving bail-out stenting. Thrombolysis in Myocardial Infarction(TIMI) 3 flow was successfully restored in 98% of patients. An average of 1.2 ± 0.5 DCB were used per patient,with mean DCB diameter of 2.6 ± 0.5 mm and average length of 23.2 ± 10.2 mm. At 30-d follow-up,there were 4 deaths(4.5%). No patients experienced abrupt closure of the infarctrelated artery and there was no reported target-lesion failure. Our preliminary experience showed that DCB angioplasty in PPCI was feasible and associated with a high rate of TIMI 3 flow and low 30-d ischaemic event.

  1. Is routine stenting for acute myocardial infarction superior to balloon angioplasty? A randomised comparison in a large cohort of unselected patients

    NARCIS (Netherlands)

    Suryapranata, H; De Luca, G; van't Hof, AWJ; Ottervanger, JP; Hoorntje, JCA; Gosselink, ATM; Zijlstra, F; de Boer, MJ; Dambrink, Jan Hendrik Everwijn

    2005-01-01

    Objective: To evaluate the impact of routine stenting, compared with balloon angioplasty, in unselected patients presenting with ST segment elevation myocardial infarction (STEMI). Design: Randomised trial. Setting: Tertiary referral centre. Participants: All patients presenting with STEMI randomly

  2. Stent-Apposition Salvage of an Anterior Tibial Artery After Inadvertent Angioplasty Balloon Retention During CTO Revascularization.

    Science.gov (United States)

    Choudry, R; Deutsch, E; Durinka, J; Dhir, T

    2016-01-01

    Progressive improvement in the ability to treat complete total occlusions in the tibial level arterial circulation have made it possible to revascularize patients with critical limb ischemia. A 59 year old male presented with a complete total occlusion of his anterior tibial artery with distal reconstitution through peroneal artery collaterals. During attempted angioplasty a balloon was retained within the patent portion of the target vessel. Two 3.0 mm drug eluting coronary stents were deployed across the length of the balloon with excellent luminal preservation. Successful CTO revascularization was completed and a strong dorsalis pedis artery pulse was restored following intervention.

  3. Deep sea water prevents balloon angioplasty-induced hyperplasia through MMP-2: an in vitro and in vivo study.

    Science.gov (United States)

    Li, Pei-Chuan; Pan, Chun-Hsu; Sheu, Ming-Jyh; Wu, Chin-Ching; Ma, Wei-Fen; Wu, Chieh-Hsi

    2014-01-01

    Major facts about the development of restenosis include vascular smooth muscle cells (VSMCs) proliferation and migration. A previous study showed that in vitro treatment with magnesium chloride has the potential to affect the proliferation and migration of VSMCs. Magnesium is the major element in deep sea water (DSW) and is a biologically active mineral. It is unclear whether DSW intake can prevent abnormal proliferation and migration of VSMCs as well as balloon angioplasty-induced neointimal hyperplasia. Thus, we attempted to evaluate the anti-restenotic effects of DSW and its possible molecular mechanisms. Several concentrations of DSW, based on the dietary recommendations (RDA) for magnesium, were applied to a model of balloon angioplasty in SD rats. The results showed that DSW intake markedly increased magnesium content within the vascular wall and reduced the development of neointimal hyperplasia. The immunohistochemical analysis also showed that the expression of proteins associated with cell proliferation and migration were decreased in the balloon angioplasty groups with DSW supplement. Furthermore, in vitro treatment with DSW has a dose-dependent inhibitory effect on serum-stimulated proliferation and migration of VSMCs, whose effects might be mediated by modulation of mitogen-activated protein kinase (MAPK) signaling and of the activity of matrix metalloproteinase-2 (MMP-2). Our study suggested that DSW intake can help prevent neointimal hyperplasia (or restenosis), whose effects may be partially regulated by magnesium and other minerals.

  4. Deep sea water prevents balloon angioplasty-induced hyperplasia through MMP-2: an in vitro and in vivo study.

    Directory of Open Access Journals (Sweden)

    Pei-Chuan Li

    Full Text Available Major facts about the development of restenosis include vascular smooth muscle cells (VSMCs proliferation and migration. A previous study showed that in vitro treatment with magnesium chloride has the potential to affect the proliferation and migration of VSMCs. Magnesium is the major element in deep sea water (DSW and is a biologically active mineral. It is unclear whether DSW intake can prevent abnormal proliferation and migration of VSMCs as well as balloon angioplasty-induced neointimal hyperplasia. Thus, we attempted to evaluate the anti-restenotic effects of DSW and its possible molecular mechanisms. Several concentrations of DSW, based on the dietary recommendations (RDA for magnesium, were applied to a model of balloon angioplasty in SD rats. The results showed that DSW intake markedly increased magnesium content within the vascular wall and reduced the development of neointimal hyperplasia. The immunohistochemical analysis also showed that the expression of proteins associated with cell proliferation and migration were decreased in the balloon angioplasty groups with DSW supplement. Furthermore, in vitro treatment with DSW has a dose-dependent inhibitory effect on serum-stimulated proliferation and migration of VSMCs, whose effects might be mediated by modulation of mitogen-activated protein kinase (MAPK signaling and of the activity of matrix metalloproteinase-2 (MMP-2. Our study suggested that DSW intake can help prevent neointimal hyperplasia (or restenosis, whose effects may be partially regulated by magnesium and other minerals.

  5. Balloon pulmonary angioplasty: applicability of C-Arm CT for procedure guidance

    Energy Technology Data Exchange (ETDEWEB)

    Hinrichs, Jan B. [Department for Diagnostic and Interventional Radiology, Member of the German Center for Lung Research (DZL), Hannover Medical School, Hannover (Germany); Institute for Diagnostic and Interventional Radiology, Hannover Medical School, Hannover (Germany); Renne, Julius; Wacker, Frank K.; Meyer, Bernhard C. [Department for Diagnostic and Interventional Radiology, Member of the German Center for Lung Research (DZL), Hannover Medical School, Hannover (Germany); Hoeper, Marius M.; Olsson, Karen M. [Clinic for Pneumology, Member of the German Center for Lung Research (DZL), Hannover Medical School, Hannover (Germany)

    2016-11-15

    To investigate the feasibility of and compare two C-Arm CT (CACT) guidance methods during balloon pulmonary angioplasty (BPA). Forty-two BPAs [27 CTEPH patients (nine males, 70 ± 14y)] targeting 143 pulmonary arteries were included. Twenty-two BPAs were guided by contrast-enhanced CACT acquired immediately before BPA (G3D). In another 20 BPAs (G2D), two orthogonal fluoroscopy images of the chest where acquired to compute a registration of a previously acquired CACT. Volume rendering-based graphic representations (VRT guidance) were generated indicating the origin and course of the vessels. Based on VRT guidance, the intervention was planned. Procedure durations and radiation exposure data were compared between the two groups (Wilcoxon test). The overall intervention time was approximately 2 h in both groups (p = 0.31). BPA was successfully performed in G3D 91 % and G2D 94 %. No significant difference was found concerning the mean dose area product (DAP) related to fluoroscopy (p = 0.38), while DAP related to DSA was slightly higher in G3D (p = 0.048). Overall, DAP was significantly higher in G3D (p = 0.002). The use of CACT for procedure guidance in patients undergoing BPA is feasible and accurate. Image fusion of a pre-acquired CACT can be used to decrease radiation exposure due to multiple BPA sessions. (orig.)

  6. Outcome of patients undergoing balloon angioplasty in the two months prior to noncardiac surgery.

    Science.gov (United States)

    Brilakis, Emmanouil S; Orford, James L; Fasseas, Panayotis; Wilson, Stephanie H; Melby, Steven; Lennon, Ryan J; Berger, Peter B

    2005-08-15

    We report on the incidence of adverse cardiac events in 350 patients who underwent noncardiac surgery within 2 months of successful balloon angioplasty (BA) at our institution between 1988 and 2001. Three patients died perioperatively (n = 1) or had myocardial infarction (n = 2) (0.9%, 95% confidence interval [CI] 0.2% to 2.5%), which is a lower incidence than that reported for patients undergoing noncardiac surgery after stenting (3.9% to 32%). One patient died, and 2 had a nonfatal myocardial infarction. All 3 (1.6%, 95% CI 0.3% to 4.6%) were among the 188 patients who underwent surgery within 2 weeks of BA. Repeat target vessel revascularization was performed in 10 patients (2.9%, 95% CI 1.4% to 5.2%): in 3 (1.6%, 95% CI 0.3% to 4.6%) of 188 patients who underwent surgery within 2 weeks of BA and in 7 (5.1%, 95% CI 2.1% to 10.2%) of 138 patients who underwent surgery within 3 to 7 weeks of BA. Therefore, in patients in whom percutaneous coronary revascularization is required before noncardiac surgery, BA appears to be safe, especially in patients who need to undergo surgery early after percutaneous coronary intervention.

  7. Percutaneous recanalization and balloon angioplasty of congenital isolated local atresia of the aortic isthmus in adults.

    Science.gov (United States)

    Joseph, G; Mandalay, A; Rajendiran, G

    2001-08-01

    Congenital isolated local atresia of the aortic isthmus is anatomically similar and morphogenetically related to congenital coarctation of the aorta and was encountered in 4 out of 26 consecutive adult patients selected for coarctation angioplasty at our center. Anterograde recanalization of the atresia was safely and successfully accomplished in all four patients, using a brachial approach. Balloon dilation in the four patients, with ancillary stent implantation in one patient, resulted in reduction of translesion gradient from 84 +/- 11 mm Hg to 9 +/- 7 mm Hg without complications. Angiography in the three non-stented patients after a mean follow-up of 13 months showed no evidence of restenosis, dissection or aneurysm formation, though one patient had mild dilatation of the posterior aspect of the aortic isthmus. The clinical presentation of patients with isolated local aortic atresia, and their short- to mid-term response to percutaneous treatment, is similar to that of patients with isolated severe coarctation of aorta. Copyright 2001 Wiley-Liss, Inc.

  8. Randomized Trial of the SMART Stent versus Balloon Angioplasty in Long Superficial Femoral Artery Lesions: The SUPER Study

    Energy Technology Data Exchange (ETDEWEB)

    Chalmers, Nicholas, E-mail: nicholas.chalmers@cmft.nhs.uk [Manchester Royal Infirmary, Department of Radiology (United Kingdom); Walker, Paul T. [James Cook University Hospital, Department of Radiology (United Kingdom); Belli, Anna-Maria [St. George' s Healthcare NHS Trust, Department of Radiology (United Kingdom); Thorpe, Anthony P. [Aberdeen Royal Infirmary, Department of Radiology (United Kingdom); Sidhu, Paul S. [King' s College Hospital, Department of Radiology (United Kingdom); Robinson, Graham [Hull Royal Infirmary, Department of Radiology (United Kingdom); Ransbeeck, Mariella van [Johnson and Johnson Medical NV/SA, Cordis (Belgium); Fearn, Steven A. [Johnson and Johnson Medical Ltd., Cordis (United Kingdom)

    2013-04-15

    To determine whether primary stenting reduces the rate of restenosis compared with balloon angioplasty alone in the endovascular treatment of long superficial femoral artery lesions; and to assess the effect of treatment on quality of life. A total of 150 patients with superior femoral artery occlusion or severe stenosis of 5-22 cm length from 17 UK centers were randomized to either primary stenting with the SMART stent or balloon angioplasty (i.e., percutaneous transluminal angioplasty, PTA). Bailout stent placement was permitted in case of inadequate result from PTA. The primary end point was restenosis measured by duplex ultrasound at 1 year. Quality-of-life assessments were performed by the EuroQol (EQ)-5D questionnaire. Mean lesion length was 123.0 mm in the stent group and 116.8 mm in the PTA group. A total of 140 (93.3 %) of 150 had total occlusions. At 12 months' follow-up, restenosis measured by Duplex ultrasound was not significantly different between the stent and PTA groups by intention-to-treat or as-treated analyses: 47.2 versus 43.5 % (p = 0.84) and 40.8 versus 46.7 % (p = 0.68), respectively. There were fewer target lesion revascularizations in patients randomized to stenting, but this did not reach statistical significance (12.5 vs. 20.8 %, p = 0.26). There was no difference in the rate of amputation. Patients in both groups reported improved quality of life. Primary stenting of long lesions in predominantly occluded superficial femoral arteries does not reduce the rate of binary restenosis compared with balloon angioplasty and bailout stenting. Both treatment strategies conferred a meaningful and sustained improvement to the quality of life of patients with severe superficial femoral artery disease.

  9. Finite Element Modeling of Balloon Angioplasty by Considering Overstretch of Remnant Non-diseased Tissues in Lesions

    Science.gov (United States)

    Gasser, T. Christian; Holzapfel, Gerhard A.

    2007-06-01

    The paper deals with the modeling of balloon angioplasty by considering the balloon-induced overstretch of remnant non-diseased tissues in atherosclerotic arteries. A stenotic artery is modeled as a heterogenous structure composed of adventitia, media and a model plaque, and residual stresses are considered. The constitutive models are able to capture the anisotropic elastic tissue response in addition to the inelastic phenomena associated with tissue stretches beyond the physiological domain. The inelastic model describes the experimentally-observed changes of the wall during balloon inflation, i.e. non-recoverable deformation, and tissue weakening. The contact of the artery with a balloon catheter is simulated by a point-to-surface strategy. The states of deformations and stresses within the artery before, during and after balloon inflation are computed, compared and discussed. The 3D stress states at physiological loading conditions before and after balloon inflation differ significantly, and even compressive normal stresses may occur in the media after dilation.

  10. Endovascular brachytherapy from Re-188-filled balloon catheter to prevent restenosis following angioplasty; Endovaskulaere Brachytherapie mit einem Re-188-gefuellten Ballonkatheter zur Praevention der Restenose nach Angioplastie

    Energy Technology Data Exchange (ETDEWEB)

    Kotzerke, J. [Ulm Univ. (Germany). Abt. Nuklearmedizin; Kropp, J. [Technische Univ. Dresden (Germany). Klinik und Poliklinik fuer Nuklearmedizin

    2001-12-01

    Stent implantation and endovascular brachytherapy are the single effective methods to reduce restenosis after angioplasty. Gamma- and beta-emitter can be applied. The use of a liquid beta-emitter filled balloon catheter allows nuclear medicine to participate in this new concept of therapy due to the unsealed source. From various beta-emitters Re-188-perrhenate seems to be the most attractive one regarding logistic, radiation protection and costs. Feasibility of the method was demonstrated by several groups. Interim analysis of ECRIS-2 demonstrate an effectiveness comparable to the best of other irradiation data. (orig.) [German] Die endovaskulaere Brachytherapie ist neben der Stentimplantation bisher die einzige Methode, mit der die Restenoserate nach Angioplastie (PTCA) deutlich reduziert werden kann. Sowohl Gamma- wie auch Betastrahler sind einsetzbar. Die Anwendung eines fluessigen Betastrahlers in einem Ballonkatheter erlaubt dem Nuklearmediziner, an diesem Therapiekonzept zu partizipieren, da es sich um die Anwendung eines offenen radioaktiven Isotops handelt. Von den diversen moeglichen Betastrahlern erscheint Re-188-Perrhenat am geeignetsten zu sein im Hinblick auf die Logistik, den Strahlenschutz und die Kosten. Die Praktikabilitaet dieser Methode wurde von mehreren Zentren bestaetigt. Eine Zwischenauswertung der ECRIS-2-Studie aus Ulm ergibt Daten, die grossen amerikanischen Studien keineswegs nachstehen. (orig.)

  11. Balloon angioplasty of coarctation of the aorta: a safe alternative for surgery in adults: immediate and mid-term results.

    Science.gov (United States)

    Koerselman, J; de Vries, H; Jaarsma, W; Muyldermans, L; Ernst, J M; Plokker, H W

    2000-05-01

    Patients with coarctation of the aorta can be treated either with surgery or with balloon angioplasty. So far, the last method has proved to be successful in children, but results of this treatment in (young) adults are virtually unknown. The aim of this study was to evaluate the immediate and mid-term follow-up results of balloon angioplasty of native coarctation in (mainly young) adults. Coarctation of the aorta was diagnosed by means of ultrasound or angiography, and defined as a stenosis with a pressure gradient greater than 20 mm Hg. The balloon angioplasty-procedure was carried out under complete anesthesia, and was considered to be successful, if the pressure gradient was reduced to less than 20 mm Hg. Nineteen consecutive adults (12 males, 7 females; aged 14-67 years, median 29) with native coarctation were treated from 1995-99. Mean pressure gradient decreased from 49.3+/- 20.8 to 4.8+/-8.2 mm Hg (P<0.0001). One patient showed a suboptimal result with a residual pressure gradient of 28 mm Hg. In one other patient a stent was placed on request of the referring physician. Follow-up was 100% complete and ranged from 3-47 months (mean 20.2+/- 12.9). At 1-year follow-up mean systolic blood pressure was reduced from 159.4+/-19.5 to 132.5+/-17.6 mm Hg (n = 18; P<0.0001), and mean ankle-arm pressure index improved from 0.73+/-0.09 to 0.96+/-0.05 (n = 18; P<0.0001). Anti-hypertensive medication could either be reduced or stopped in 7 patients (53.8%). With ultrasound or angiography or MRI, no patients had signs of aneurysm formation or worsening restenosis during follow-up. In adult patients with uncomplicated native coarctation of the aorta, balloon angioplasty (without stenting) would seem to be an excellent and safe alternative for surgery. In our hospital it has completely replaced surgical correction in such patients.

  12. Effect and outcome of balloon angioplasty and stenting of the iliac arteries evaluated by intravascular ultrasound

    DEFF Research Database (Denmark)

    Vogt, K J; Rasmussen, John Bøje Grønvall; Just, S;

    1999-01-01

    To document the mechanism of percutaneous transluminal angioplasty (PTA) and stenting of the iliac arteries, and to relate the effect to patency.......To document the mechanism of percutaneous transluminal angioplasty (PTA) and stenting of the iliac arteries, and to relate the effect to patency....

  13. Prolonged high-pressure balloon angioplasty of femoropopliteal lesions:Impact on stent implantation rate and mid-term outcome

    Institute of Scientific and Technical Information of China (English)

    Gianluca Rigatelli; Mariano Palena; Paolo Cardaioli; Fabio dellAvvocata; Massimo Giordan; Dobrin Vassilev; Marco Manzi

    2014-01-01

    Objectives To assess the impact on stent implantation rate and mid-term outcomes of prolonged high pressure angioplasty of femoropopliteal lesions. Methods We retrospectively enrolled 620 consecutive patients from January 2011 to December 2011 (75.6 ±12.3 years, 355 males, 76.5%in Rutherford class 5-6), referred for critical limb ischemia and submitted to prolonged high-pressure angioplasty of femoropopliteal lesions. The definition of prolonged high-pressure angioplasty includes dilation to at least 18 atm for at least 120 s. Proce-dural data, and clinical and instrumental follow-up were analyzed to assess stent implantation rate and mid-term outcomes. Results The preferred approach was ipsilateral femoral antegrade in 433/620 patients (69.7%) and contralateral cross-over in 164/620 (26.4%) and pop-liteal retrograde+femoral antegrade in 23/620 (3.7%). Techniques included subintimal angioplasty in 427/620 patients (68.8%) and endolu-minal angioplasty in 193/620 patients (31.2%). The prolonged high pressure balloon angioplasty procedure was successful in 86.2%(minor intra-procedural complications rate 15.7%), stent implantation was performed in 74 patients (11.9%), with a significant improvement of ankle-brachial index (0.29 ±0.6 vs. 0.88 ±0.3, P<00.1) and Rutherford class (5.3 ±0.8 vs. 0.7 ±1.9, P<0.01), a primary patency rate of 86.7%, restenosis of 18.6%on Doppler ultrasound and a target lesion revascularization of 14.8%at a mean follow-up of 18.1 ±6.4 months (range 1-24 months). Secondary patency rate was 87.7%. Conclusions Prolonged high pressure angioplasty of femoropopliteal lesions appears to be safe and effective allowing for an acceptable patency and restenosis rates on mid-term.

  14. Optical coherence tomography monitoring of angioplasty balloon inflation in a deployment tester

    Science.gov (United States)

    Azarnoush, Hamed; Vergnole, Sébastien; Bourezak, Rafik; Boulet, Benoit; Lamouche, Guy

    2010-08-01

    We present an innovative integration of an intravascular optical coherence tomography probe into a computerized balloon deployment system to monitor the balloon inflation process. The high-resolution intraluminal imaging of the balloon provides a detailed assessment of the balloon quality and, consequently, a technique to improve the balloon manufacturing process. A custom-built swept-source optical coherence tomography system is used for real-time imaging. A semicompliant balloon with a nominal diameter of 4 mm is fabricated for the experiments. Imaging results correspond to balloon deployment in air and inside an artery phantom. A characterization of the balloon diameter, wall thickness, compliance, and elastic modulus is provided, based on image segmentation. Using the images obtained from the probe pullback, a three-dimensional visualization of the inflated balloon is presented.

  15. Emergent intracranial balloon angioplasty and bailout self-expandable stent placement in acute large vessel occlusion of the anterior circulation: Experience of a single institution

    Energy Technology Data Exchange (ETDEWEB)

    Heo, Young Jin; Seo, Jung Hwa; Jeong, Hae Woong [Busan Paik Hospital, Inje University, Busan (Korea, Republic of)

    2017-06-15

    To evaluate the outcomes of angioplasty for recanalization after acute ischemic stroke (AIS). The study population was selected from 134 patients who underwent endovascular revascularization therapy (ERT) for AIS between October 2011 and May 2014. Of those 134 patients, 39 who underwent balloon angioplasty with or without stent insertion were included in this study. Balloon angioplasty was the primary treatment for nine patients and a rescue method for 30 patients. The revascularization rate at 7 days, procedure-related complications, and clinical outcomes at 3 months were analyzed. The occlusion sites were the middle cerebral artery (n = 26), intracranial internal carotid artery (n = 10), and middle cerebral artery branch (n = 3). Angioplasty achieved successful revascularization (Thrombolysis in Cerebral Ischemia grade 2b–3) in 76.9% of patients. Computed tomography angiography performed 7 days post-procedure revealed a maintained reperfusion in 82.8% of successful cases. Only two patients had symptomatic intracerebral hemorrhage. At the 3-month follow-up, 18 (48.6%) and 10 (27.0%) patients showed good and poor functional outcomes, respectively (modified Rankin Scale scores, 0–2 and 5–6). Emergent balloon angioplasty and bailout self-expandable stent placement may be safe and effective for achieving successful revascularization in acute large vessel occlusion of the anterior circulation. It could be a feasible rescue method as well as a primary method for ERT.

  16. Lumen narrowing after percutaneous transluminal coronary balloon angioplasty follows a near gaussian distribution: a quantitative angiographic study in 1,445 successfully dilated lesions

    NARCIS (Netherlands)

    B.J.W.M. Rensing (Benno); W.R.M. Hermans (Walter); P.J. de Feyter (Pim); J.G.P. Tijssen (Jan); P.W.J.C. Serruys (Patrick); J.W. Deckers (Jaap)

    1992-01-01

    textabstractTo determine whether significant angiographic narrowing and restenosis after successful coronary balloon angioplasty is a specific disease entity occurring in a subset of dilated lesions or whether it is the tail end of a gaussian distributed phenomenon, 1,445 successfully dilated lesion

  17. Continued benefit of coronary stenting versus balloon angioplasty: one-year clinical follow-up of Benestent trial. Benestent Study Group.

    NARCIS (Netherlands)

    C.M. Miguel (Carlos); P.W.J.C. Serruys (Patrick); P.N. Ruygrok (Peter); H. Suryapranata (Harry); S. Klugmann (Silvio); P. Urban (Philip); P. den Heijer (Peter); K. Koch (Karel); R. Simon (Rudiger); M-C. Morice (Marie-Claude); P.A. Crean (Peter); J.J.R.M. Bonnier (Hans); W. Wijns (William); N. Danchin (Nicolas); C. Bourdonnec (Claude); M-A.M. Morel (Marie-Angèle); E.G. Mast (Gijs)

    1996-01-01

    textabstractObjectives. This study sought to determine the 1-year clinical follow-up of patients included in the Benestent trial. Background. The Benestent trial is a randomized study comparing elective Palmaz-Schatz stent implantation with balloon angioplasty in patients with stable angina and a de

  18. Cutting balloon angioplasty for in-stent restenosis of the aortic coarctation in a young boy presenting with systemic hypertension of the upper extremities.

    Science.gov (United States)

    Lee, Meng-Luen

    2013-12-01

    An 8.25-year-old boy was incidentally found to have systemic hypertension of the upper extremities. Blood pressures of the upper extremities were 142-150/86-98 mmHg, and those of the lower extremities 110-116/60-66 mmHg. Doppler echocardiography showed in-stent restenosis of the aortic coarctation. Traditional high-pressure balloon angioplasty failed to dilate this inveterate in-stent restenosis. Instead, a cutting balloon angioplasty was performed. The lumen was dilated from 4.80 mm to 7.89 mm. The pressure gradient dropped from 32 mmHg to 9 mmHg. Blood pressures of the upper extremities were 112-116/76-78 mmHg, and those of the lower extremities 100-104/70-72 mmHg. This paper highlights that a cutting balloon angioplasty can serve as a juste milieu to relieve in-stent restenosis of the aortic coarctation when traditional high-pressure balloon angioplasty is debatable.

  19. Clinical impact and risk stratification of balloon angioplasty for femoropopliteal disease in nitinol stenting era: Retrospective multicenter study using propensity score matching analysis

    Directory of Open Access Journals (Sweden)

    Taketsugu Tsuchiya

    2016-07-01

    Full Text Available Objective: Nitinol stenting could bring the better outcome in endovascular therapy for femoropopliteal disease. However, it might be expected that recent marked advances in both device technology and operator technique had led to improved efficacy of balloon angioplasty even in this segment. The aims of this study were to evaluate the clinical impact of balloon angioplasty for femoropopliteal disease and make risk stratification clear by propensity score matching analysis. Methods: Based on the multicenter retrospective data, 2758 patients (balloon angioplasty: 729 patients and nitinol stenting: 2029 patients, those who underwent endovascular therapy for femoropopliteal disease, were analyzed. Results: The propensity score matching procedure extracted a total of 572 cases per group, and the primary patency rate of balloon angioplasty and nitinol stenting groups after matching was significantly the same (77.2% vs 82.7% at 1 year; 62.2% vs 64.3% at 3 years; 47.8% vs 54.3% at 5 years. In multivariate Cox hazard regression analysis, significant predictors for primary patency were diabetes mellitus, regular dialysis, cilostazol use, chronic total occlusion, and intra-vascular ultra-sonography use. The strategy of balloon angioplasty was not evaluated as a significant predictor for the primary patency. After risk stratification using five items (diabetes mellitus, regular dialysis, no use of intra-vascular ultra-sonography, chronic total occlusion, and no use of cilostazol: the DDICC score, the estimated primary patency rates of each group (low, DDICC score 0–2; moderate, DDICC score 3; high risk, DDICC score 4–5 were 88.6%, 78.3%, and 63.5% at 1 year; 75.2%, 60.7%, and 39.8% at 3 years; and 66.0%, 47.1%, and 26.3% at 5 years (p < 0.0001. The primary patency rate of balloon angioplasty and nitinol stenting groups was significantly the same in each risk stratification. Conclusion: This study suggests that balloon angioplasty does

  20. Long-term outcome after balloon angioplasty of coarctation of the aorta in adolescents and adults: Is aneurysm formation an issue?

    Science.gov (United States)

    Walhout, R J; Suttorp, M J; Mackaij, G J; Ernst, J M P G; Plokker, H W M

    2009-03-01

    The purpose was to evaluate long-term outcome following balloon angioplasty for coarctation in adults. Long-term results of balloon angioplasty for native coarctation in adults remain incomplete, especially concerning the occurrence of aneurysm formation. Long-term follow-up data were collected in consecutive patients retrospectively. Results of balloon angioplasty (29 patients, age 15-71 years, during 1995-2005) for discrete, native coarctation were evaluated, including MRI or CT. Mean follow-up ranged from 2.2 to 13 years (mean 8.5 +/- 3.2). Immediate success was obtained in all patients. Early mortality or complications were not encountered. Peak systolic pressure gradient decreased from 52 +/- 21 to 7.2 +/- 7.6 mm Hg (P < 0.001). Intima tear was detected in eight procedures angiographically, without signs of dissection. Three-month follow-up angiography in these patients showed unchanged (4/8 patients) or diminished abnormalities (4/8 patients). One asymptomatic patient, known with left ventricular dysfunction due to significant aortic valve insufficiency, died suddenly 5 years after balloon angioplasty. Recoarctation occurred in one patient (3%). Late aneurysm formation was excluded by MR in 24/29 and CT in remaining 5/29 patients during follow-up, including those patients in whom intima tear was encountered immediately postangioplasty. In three of seven patients an irregular aortic contour persisted, without indication of progression or aneurysm formation. Hypertension was completely relieved in 67% (14/21 patients) and improved in 33% (7/21 patients). Balloon angioplasty for native coarctation yields low reintervention probability in adult patients. Despite occurrence of angiographically established intimal tearing, aortic dissection and aneurysm formation were not encountered. (c) 2009 Wiley-Liss, Inc.

  1. Absence of Bacteria on Coronary Angioplasty Balloons from Unselected Patients: Results with Use of a High Sensitivity Polymerase Chain Reaction Assay.

    Science.gov (United States)

    Hansen, Gorm Mørk; Nilsson, Martin; Nielsen, Claus Henrik; Holmstrup, Palle; Helqvist, Steffen; Tolker-Nielsen, Tim; Givskov, Michael; Hansen, Peter Riis

    2015-01-01

    Periodontitis is a chronic, bacterially-induced inflammatory disease of the tooth-supporting tissues, which may result in transient bacteremia and a systemic inflammatory response. Periodontitis is associated with coronary artery disease independently of established cardiovascular risk factors, and translocation of bacteria from the oral cavity to the coronary arteries may play a role in the development of coronary artery disease. Very few studies have used angioplasty balloons for in vivo sampling from diseased coronary arteries, and with varying results. Therefore, the aim of this study was to assess if bacterial DNA from primarily oral bacteria could be detected on coronary angioplasty balloons by use of an optimized sampling process combined with an internally validated sensitive polymerase chain reaction (PCR) assay. Coronary angioplasty balloons and control samples from a total of 45 unselected patients with stable angina, unstable angina/non-ST elevation myocardial infarction, and ST-elevation myocardial infarction (n = 15 in each group) were collected and analyzed using a PCR assay with high sensitivity and specificity for 16S rRNA genes of the oral microbiome. Despite elimination of extraction and purification steps, and demonstration of sensitivity levels of 25-125 colony forming units (CFU), we did not detect bacterial DNA from any of the coronary angioplasty balloons. A subsequent questionnaire indicated that the prevalence of periodontitis in the study cohort was at least 39.5%. Although coronary angioplasty balloons are unlikely to be useful for detection of bacteria with current PCR techniques in unselected patients with coronary artery disease, more studies are warranted to determine the extent to which bacteria contribute to atherosclerosis and its clinical manifestations and whether the presence of bacteria in the arteries is a transient phenomenon.

  2. Simulation of balloon angioplasty in residually stressed blood vessels-Application of a gradient-enhanced fibre damage model.

    Science.gov (United States)

    Polindara, César; Waffenschmidt, Tobias; Menzel, Andreas

    2016-08-16

    In this contribution we study the balloon angioplasty in a residually stressed artery by means of a non-local gradient-enhanced fibre damage model. The balloon angioplasty is a common surgical intervention used to extend or reopen narrowed blood vessels in order to restore the continuous blood flow in, for instance, atherosclerotic arteries. Inelastic, i.e. predominantly damage-related and elastoplastic processes are induced in the artery during its inflation resulting in an irreversible deformation. As a beneficial consequence, provided that the inelastic deformations do not exceed a specific limit, higher deformations can be obtained within the same pressure level and a continuous blood flow can be guaranteed. In order to study the mechanical response of the artery in this scenario, we make use of the non-local gradient-enhanced model proposed in Waffenschmidt et al. (2014). In this contribution, we extend this model to make use of an incompressible format in connection with a Q1Q1P0 finite element implementation. The residual stresses in the artery are also taken into account following the framework presented in Waffenschmidt (2015). From the results it becomes apparent that, when the artery is subjected to radial stresses beyond the physiological range, damage evolution is triggered in the collagen fibres. The impact of the residual stresses on the structural response and on the circumferential stress distribution along the thickness of the arterial wall is also studied. It is observed that the residual stresses have a beneficial effect on the mechanical response of the arterial wall.

  3. Ultrasonography-guided Balloon Angioplasty in an Autogenous Arteriovenous Fistula: Preliminary Results

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Ji Chang [Daejeon St Mary' s Hospital, Daejeon (Korea, Republic of); Cho, June Sik [Chungnam National University College of Medicine, Daejeon (Korea, Republic of)

    2007-09-15

    Percutaneous trasnluminal angioplasty (PTA) of a malfunctioning arteriovenous fistula (AVF) in hemodialysis patients requires the use of contrast angiography and fluoroscopy guidance. We attempted to perform this procedure under duplex ultrasound guidance to reduce the amount of contrast agent administered and to reduce the radiation dose during the interventional procedures. From September 2006 to February 2007, 45 patients received interventional treatment due to malfunctioning hemodialysis access in our hospital. Among the patients, we selected 10 patients diagnosed with stenosis of an autogenous arteriovenous fistula based on a physical examination. There were six males and four females aged 51-78 years (mean age, 59 years). Seven of these patients had a Brescia-Cinimo type fistula and three patients had a basilic vein transposition. All procedures were performed in the angiography suite. All procedures that required angioplasty were performed under duplex ultrasound guidance and then contrast angiography was performed to confirm the final patency of the vessels. Conventional angioplasty was also performed under fluoroscopy guidance for any lesions that required an additional angioplasty. The volume flow before and after the PTA and procedure time were recorded. Clinical success was defined as the performance of one or more successful hemodialysis sessions after treatment. Eight of ten patients did not require an additional angioplasty by conventional angiography after the duplex- guided angioplasty. One case showed recoiling of stenosis after the duplex-guided PTA and another case was missed at duplex scanning due to the extremely short nature of the recoiling of stenosis. The mean volume flow before and after PTA was 167 ml/min (range, 80-259 ml/min) and 394.2 ml/min (range, 120-586 ml/min), respectively. No complications associated with the duplex-guide procedure occurred. In nine cases, PTA enabled hemodialysis to be conducted more than one time. In one

  4. Percutaneous transluminal angioplasty and stenting of the vertebral artery ostium with balloon-mounted bare coronary stents

    Directory of Open Access Journals (Sweden)

    Javad Kojuri

    2011-01-01

    Full Text Available Background : Vertebral artery ostial stenosis (VAOS is one of the most frequent causes of posterior circulation stroke. Percutaneous angioplasty and stenting (PTAS is one of the treatment modalities. Patients and Methods : This is a longitudinal observational study from September 2006 to February 2009, conducted at hospitals affiliated with the Shiraz University of Medical Sciences, Shiraz, southern Iran. The patient cohort included patients with posterior circulation stroke or transient ischemic attack (TIA and more than 70% VAOS, and patients with asymptomatic VAOS of more than 70% and aplasia or total occlusion of the contralateral VA or subclavian artery. All the patients underwent PTAS with balloon-mounted bare coronary stents. Technical success, procedural complications, composite outcomes of death, stroke or TIA in the vertebrobasilar territory during the first 30 days, stroke or TIA in the vertebrobasilar territory, and restenosis during follow-up, were assessed. Results : During the study period, 81 patients (mean age 68 + 8.9 years, 63 (78% males, 71 symptomatic and 18 asymptomatic underwent the procedure. Technical success was achieved in 88 (99% patients. Procedure-related complications, other than puncture site complications, were seen in two patients (2.2%. The composite outcome of death, stroke or TIA in the vertebrobasilar territory during the first 30 days was 1%. None of the patients had clinical recurrence or restenosis during the follow-up (mean follow-up 14 months. Conclusion : Percutaneous transluminal angioplasty and stenting of the proximal VA was feasible and safe. The risk of restenosis should be analyzed in long-term studies with angiographic follow-up.

  5. Cephalic arch stenosis in autogenous brachiocephalic hemodialysis fistulas: results of cutting balloon angioplasty

    DEFF Research Database (Denmark)

    Heerwagen, Søren Thorup; Lönn, Lars; Schroeder, Torben V;

    2010-01-01

    Cephalic arch stenosis is a known cause of hemodialysis access failure in patients with brachiocephalic fistulas (BCFs). Outcomes of endovascular treatment are affected by resistance of the stenosis to balloon dilation, a high vein rupture rate and the development of early restenosis. The purpose...

  6. Preparation and characterisation of polyamide 11/montmorillonite (MMT) nanocomposites for use in angioplasty balloon applications

    Energy Technology Data Exchange (ETDEWEB)

    Halim, Khairul Anwar A. [Department of Polymer Engineering, Athlone Institute of Technology, Athlone (Ireland); School of Materials Engineering, Universiti Malaysia Perlis, Perlis (Malaysia); Farrell, Joseph B. [Department of Polymer Engineering, Athlone Institute of Technology, Athlone (Ireland); Kennedy, James E., E-mail: jkennedy@ait.ie [Department of Polymer Engineering, Athlone Institute of Technology, Athlone (Ireland)

    2013-12-16

    With increased demands on catheter balloon functionality, there is an emphasis to blend new materials which can improve mechanical performance. Polymer nanocomposites were prepared by melt blending polyamide 11 (PA 11) with organically modified montmorillonite nanoclay. The effects of incorporating the nanoclay on the short-term mechanical properties of PA 11 were assessed using a design of experiments (DoEs) approach. X-ray diffraction (XRD), transmission electron microscopy (TEM), differential scanning calorimetry (DSC) and dynamic mechanical thermal analysis techniques (DMA) were used to characterise the morphology of the nanocomposites. Design of experiments studies revealed that the optimum nanocomposites properties can be achieved by carefully controlling the melt compounding parameters. XRD and TEM data proved that exfoliated clay morphologies existed within the matrix at low clay loading (2%). Whereas the interaction between the polymer matrix and nanoclay was quantified in the DMA spectra, showed a significant increase in storage modulus (up to 80%). The reinforcing effect of nanoclay within the PA 11 was further investigated using mechanical testing, where significant increases in the ultimate tensile strength and strain at break of reinforced tri-layer balloon tubing were observed. - Highlights: • TEM reveals the coexistence of exfoliated and intercalated nanostructures. • Isothermal crystallisation studies found that the nano-clays reduced the crystallisation time. • Significant increase in the storage modulus was due to the reinforcing effect of the nano-clay platelets. • It was observed that the activation energy values decreased due to the presence of nanoclay.

  7. Safety and efficacy of limus-eluting stents and balloon angioplasty for sirolimus-eluting in-stent restenosis

    Energy Technology Data Exchange (ETDEWEB)

    Ota, Hideaki [Division of Interventional Cardiology, MedStar Washington Hospital Center, Washington, DC 20010 (United States); Mahmoudi, Michael [University of Surrey, Guildford Road, Surrey, GU2-7XH (United Kingdom); Kitabata, Hironori; Torguson, Rebecca; Chen, Fang; Satler, Lowell F.; Suddath, William O.; Pichard, Augusto D. [Division of Interventional Cardiology, MedStar Washington Hospital Center, Washington, DC 20010 (United States); Waksman, Ron, E-mail: ron.waksman@medstar.net [Division of Interventional Cardiology, MedStar Washington Hospital Center, Washington, DC 20010 (United States)

    2015-03-15

    Objectives: The aim of this study was to compare the safety and efficacy of everolimus-eluting stent (EES), sirolimus-eluting stent (SES), and plain old balloon angioplasty (POBA) for the treatment of SES in-stent restenosis (S-ISR). Background: The optimal treatment for drug-eluting in-stent restenosis remains controversial. Methods: The study cohort comprised 310 consecutive patients (444 lesions) who presented with S-ISR to our institution and underwent treatment with EES (43 patients), SES (102), or POBA (165). The analyzed clinical parameters were the 1-year rates of death, Q-wave myocardial infarction (MI), target lesion revascularization (TLR), target vessel revascularization (TVR), definite stent thrombosis (ST) and major adverse cardiac event (MACE) defined as the composite of death, MI, or TLR at 1-year. Results: The three groups were well matched for the conventional risk factors for coronary artery disease except for smoking. The 1-year analyzed clinical parameters were similar in the three groups: MACE (EES = 14%, SES = 18%, POBA = 20%; p = 0.65), death (EES = 2.3%, SES = 6.2%, POBA = 6.1%; p = 0.61), MI (EES = 4.8%, SES = 2.1%, POBA = 2.5%; p = 0.69), TLR (EES = 11.9%, SES = 12.1%, POBA = 24%; p = 0.78), and TVR (EES = 11.9%, SES = 24.8%, POBA = 22.2%; p = 0.23). There were no cases of definite ST. MACE-free rate was significantly lower in patients with recurrent in-stent restenosis (log-rank p = 0.006). Presentation with acute MI, number of treated lesions and a previous history of MI were found to be independent predictors of MACE. Conclusions: In patients presenting with S-ISR, treatment with implantation of an EES, SES, or POBA is associated with similar clinical outcomes. Patients presenting with recurrent ISR may have a poorer clinical outcome.

  8. Monitoring of gadolinium-BOPTA uptake into the vessel wall during magnetic resonance (MR)-guided angioplasty of the peripheral arteries with a paclitaxel/gadolinium-BOPTA-coated balloon. An experimental study at 3 Tesla

    Energy Technology Data Exchange (ETDEWEB)

    Neizel, M.; Kelm, M. [University Hospital Duesseldorf (Germany). Dept. of Cardiology, Pneumology and Angiology; Ruebben, A.; Weiss, N. [Aachen Resonance, Aachen (Germany); Guenther, R.W. [University Hospital Aachen (Germany). Dept. of Radiology; Krombach, G.A. [University Hospital Giessen (Germany). Dept. of Radiology

    2014-04-15

    Purpose: The success of paclitaxel distribution within the vessel wall during paclitaxel-coated balloon angioplasty to prevent restenosis cannot be monitored under X-ray guidance. The aim of this pilot study was to demonstrate the feasibility of monitoring Gadolinium-BOPTA delivery within the vessel wall during magnetic resonance (MR)-guided paclitaxel/Gadolinium-BOPTA-coated balloon angioplasty of the peripheral arteries. Materials and methods: 6 pigs (47 ± 2 kg) were investigated. All experiments were performed using a 3 Tesla MR scanner. MR-guided bilaterial angioplasty of the iliac arteries was performed using a paclitaxel/MR contrast agent-coated balloon catheter. The feasibility of monitoring the delivery of Gadolinium-BOPTA to the vessel was assessed in 4 animals. In two additional animals, bilateral stenosis was surgically induced in the iliac arteries. Delivery of paclitaxel to the vessel wall was monitored using a 3 D T1-weighted gradient echo (GE) sequence for delineation of the vessel wall. Normalized signal intensity (SI) of the vessel wall was measured before and repeatedly after the intervention for 45 min. in all animals. Results: Paclitaxel/gadolinium-BOPTA-coated balloon angioplasty was successfully accomplished in all iliac arteries (n = 12). In animals with stenosis MR-angiography demonstrated successful dilatation (n = 4). The normalized SI of the vessel wall on T1-weighted GE images significantly increased after the intervention in all animals with and without stenosis for more than 45 min. (p < 0.001). Conclusion: Monitoring of Gadolinium-BOPTA into the vessel wall during MR-guided coated balloon angioplasty is feasible. This is a first step towards providing a tool for the online control of homogenous drug delivery after paclitaxel-coated balloon angioplasty. (orig.)

  9. Distal coronary hemoperfusion during percutaneous transluminal coronary angioplasty

    NARCIS (Netherlands)

    deMuinck, ED; denHeijer, P; vanDijk, RB; Crijns, HJGM; Hillige, HL; Lie, KI

    1996-01-01

    Distal coronary hemoperfusion during percutaneous transluminal coronary angioplasty (PTCA)-with an autoperfusion balloon or active system-facilitates prolonged balloon inflation. Prolonged inflations may tack up intimal dissections and improve the primary angioplasty result in complex lesions. Addit

  10. Acute embolic occlusion of the right common iliac artery after revision total hip arthroplasty treated with catheter-directed thrombolysis and balloon angioplasty: A case report

    Directory of Open Access Journals (Sweden)

    Hongqi Yang

    2015-07-01

    Full Text Available Methods: A 63-year-old woman with atrial fibrillation presented clinical symptoms and signs of acute ischemia in the right lower extremity on the 17th postoperative day after revision total hip arthroplasty of the left hip for aseptic loosening of femoral component. Aspirin was discontinued 7 days before surgery. Both computed tomography angiography and digital subtraction angiography demonstrated complete occlusion of the right common iliac artery. An emergency catheter-directed thrombolysis with urokinase combined with balloon angioplasty was performed to obtain complete patency of the right common iliac artery. Results: The patient received anticoagulation and antiplatelet therapy postoperatively and was fine at the 2-year follow-up. Conclusions: This case demonstrated that catheter-directed thrombolysis combined with balloon angioplasty could be an efficacious, minimally invasive approach for the treatment of acute embolic occlusion of the common iliac artery. Preoperative anticoagulation for patients undergoing total hip arthroplasty with long-term use of aspirin for atrial fibrillation needs further investigation.

  11. Randomized trial of Legflow® paclitaxel eluting balloon and stenting versus standard percutaneous transluminal angioplasty and stenting for the treatment of intermediate and long lesions of the superficial femoral artery (RAPID trial): Study protocol for a randomized controlled trial

    NARCIS (Netherlands)

    A. Karimi; S.W. de Boer (Sanne W.); D.A.F. Van Den Heuvel; B. Fioole (Bram); D. Vroegindeweij (Dammis); J.M.M. Heyligers (Jan); P.N.M. Lohle (Paul N.M.); O.E. Elgersma (Otto E.); R.P.T. Nolthenius (Rudolf ); J.A. Vos (Jan Albert); J.-P.P.M. de Vries (Jean-Paul)

    2013-01-01

    textabstractBackground: Restenosis after percutaneous transluminal angioplasty (PTA) of the superficial femoral artery (SFA) may occur in 45% of patients at 2 years follow-up. Paclitaxel-coated balloons have been found to reduce neointimal hyperplasia, and thus reduce restenosis. Recently, the Legfl

  12. 切割球囊扩张在股浅动脉长段闭塞治疗中的作用%Angioplasty with cutting balloon in patient with long segmental obstruction of superficial femoral artery

    Institute of Scientific and Technical Information of China (English)

    王爱林; 徐恒; 刘军; 韩圣辉

    2012-01-01

    Objective To compare the technical success rate and midterm results of cutting balloon angioplasty (CBA) to conventional balloon angioplasty (BA) for treatment of long segmental obstruction of the superficial femoral artery. Methods Between March 2009 and May 2010, 33 patients with long segmental obstruction of the superficial femoral artery treated with conventional angioplasty underwent cutting angioplasty. Follow-up consisted clinical examination and computed tomographic angiography at interval of one year. Results After conventional angioplasty there were still severe stenoses in the treated segments of the superficial femoral artery among the 33 selected patients. The stenosis rate decreased from 60% -95% (average 78%) post-conventional angioplasty to 15% -45% (average 36%) after cutting balloon angioplasty. Three patients complicated minor vessel dissection without other major complication. The one year patency of the cutting balloon angioplasty was 66% , which is better than the patency of the conventional balloon angioplasty ( 37% ) . Conclusion Cutting balloon angioplasty provides better vessel patency additional to balloon angioplasty in the treatment of the long segmental obstruction of the superficial femoral artery.%目的 分析评价在常规球囊扩张基础上加用切割球囊治疗股浅动脉长段闭塞的治疗效果和中期通畅率.方法 应用了切割球囊扩张治疗33例股浅动脉长段闭塞患者,导丝通过闭塞段后,首先应用常规球囊进行扩张后,进行动脉造影,对常规球囊扩张后仍有明显狭窄部位进行切割球囊扩张,再次动脉造影评价切割球囊扩张效果.术后对经过治疗的24例患者进行1年的中期随访,并与前期完成的24例单纯常规球囊扩张的1年通畅率进行比较,总结分析两者的中期通畅率、再狭窄的病变特点.结果 在股浅动脉长段闭塞部位进行常规球囊扩张后,均存在不同部位的短段重度狭窄,狭窄部位位于

  13. The Effect of Charcot Neuroarthropathy on Limb Preservation in Diabetic Patients with Foot Wound and Critical Limb Ischemia after Balloon Angioplasty

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    Mehmet Burak Çildağ

    2017-01-01

    Full Text Available Objective. The aim of this article is to investigate one-year limb preservation rates after below-the-knee angioplasty in patients with diabetic foot wound who only have critical limb ischemia (CLI and those who have Charchot neuroarthropathy (CN accompanied by CLI. Methods. This single-center, retrospective study consists of 63 patients with diabetic foot wound who had undergone lower extremity balloon angioplasty of at least 1 below-the-knee (BTK vessel. Only those patients with postprocedural technical success of 100% were selected from the database. All patients were classified into two groups as patients with CLI and CN and patients with CLI only without CN. The Kaplan-Meier method was used to compare the limb preservation rates for the two groups. Results. There was no statistically significant difference between patient age, gender, diabetic disease duration, and comorbid disease such as chronic renal insufficiency, hypertension, and coronary artery disease of the two groups (p>0.05. Limb preservation in the 12 months was 59.1% in the CN group and 92.7% in the group without CN. Also, limb preservation rates between the two groups displayed statistically significant differences (p<0.005. Conclusion. This study showed that CLI can accompany CN in patients with diabetes. Limb preservation rates with endovascular treatment in diabetic patients with CLI only are better than in diabetic patients with CLI and CN.

  14. Differences in optical coherence tomographic findings and clinical outcomes between excimer laser and cutting balloon angioplasty for focal in-stent restenosis lesions.

    Science.gov (United States)

    Nishino, Masami; Lee, Yasuharu; Nakamura, Daisuke; Yoshimura, Takahiro; Taniike, Masayuki; Makino, Nobuhiko; Kato, Hiroyasu; Egami, Yasuyuki; Shutta, Ryu; Tanouchi, Jun; Yamada, Yoshio

    2012-10-01

    In-stent restenosis (ISR), especially focal ISR, after percutaneous coronary intervention (PCI) remains one of the major clinical problems in the drug-eluting stent (DES) era. Several reports have revealed that excimer laser coronary angioplasty (ELCA) is useful for ISR; however, detailed findings after ELCA are unknown. Therefore, we investigated the condition of the neointima after ELCA for ISR with optical coherence tomography (OCT) and compared the OCT findings and clinical outcome between ELCA and cutting-balloon angioplasty (CBA). Twenty-one consecutive patients with focal ISR who underwent ELCA or CBA were enrolled. All patients underwent 12- to 15-month follow-up coronary angiography. OCT was performed immediately after successful PCI to evaluate the neointimal condition in the ISR lesion. We compared the following OCT parameters between ELCA and CBA groups: maximal thickness of remaining in-stent neointima (MTN), number of tears, minimum lumen dimension (MLD), and minimum lumen area (MLA). We also evaluated clinical outcomes, including target vessel revascularization, acute myocardial infarction, death, and stent thrombosis. MLA in the ELCA group (n = 10) was significantly larger than in the CBA group, and number of tears in the ELCA group was significantly lower than in the CBA group. A trend was shown toward lower TLR with ELCA versus CBA (10.0% vs 45.5%). OCT immediately after ELCA for ISR lesions revealed larger lumen area and smaller number of tears compared with CBA, which may support favorable effects of ELCA for focal ISR.

  15. Early and late effects of coumarin therapy started before percutaneous coronary intervention: Clinical, angiographic and cost-effective outcome of the Balloon Angioplasty and Anticoagulation Study (BAAS).

    Science.gov (United States)

    Ten Berg, J M; Kelder, J C; Suttorp, M J; Mast, E G; Bal, E T; Ernst, J M P G; Plokker, H W M

    2002-05-01

    Coronary angioplasty frequently creates a thrombogenic surface with subsequent mural thrombosis that may lead to acute complications and possibly stimulates the development of restenosis. Whether coumarins can prevent these complications is unclear. In the Balloon Angioplasty and Anticoagulation Study (BAAS), the effect of coumarins started before the procedure on early and late outcome was studied. Patients were randomised to aspirin only or to aspirin plus coumarins. Half of the patients were randomised to undergo six-month angiographic follow-up. Study medication was started one week before coronary angioplasty and the target international normalised ratio (INR) was 2.1-4.8 during angioplasty and six-month follow-up. 'Optimal' anticoagulation was defined as an INR in the target range for at least 70% of the follow-up time. In addition, cost-effectiveness of coumarin treatment was measured. At one year death, myocardial infarction, target-lesion revascularisation and stroke were observed in 14.3% of the 530 patients randomised to aspirin plus coumarin versus in 20.3% of the 528 patients randomised to aspirin alone (relative risk 0.71; 95% CI 0.54-0.93). The incidence of major bleedings and false aneurysms during hospitalisation was 3.2% and 1.0%, respectively, (relative risk 3.39; 95% CI 1.26-9.11). Optimal anticoagulation was an independent predictor of late thrombotic events (relative risk, 0.33; 95% CI, 0.19-0.57). Quantitative coronary analysis was performed of 301 lesions in the ASA group and of 297 lesions in the coumarin group. At six months, the minimal luminal diameter was similar in the ASA and coumarin group. However, optimal anticoagulation was an independent predictor of angiographic outcome at six months. Optimal anticoagulation led to a 0.21 mm (95% CI: 0.05-0.37) larger MLD as compared with suboptimal anticoagulation whereas aspirin use led to a 0.12 mm (95% CI -0.28-0.04) smaller MLD. When including all costs, the savings associated with coumarin

  16. The use of primary stenting or balloon percutaneous transluminal coronary angioplasty for the treatment of acutely occluded saphenous vein grafts. Results from the Brazilian National Registry - CENIC

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    Luiz Alberto Mattos

    2001-06-01

    Full Text Available OBJECTIVE: We conducted a comparative analysis of the in-hospital outcomes of patients who underwent primary percutaneous transluminal angioplasty (PTCA or stent implantation because of an acute myocardial infarction (AMI related to an acute vein graft occlusion. METHODS: Since 1991 the Brazilian Society of Hemodynamic and Interventional Cardiology has maintained a large database (CENIC. From these, we selected all consecutive patients, who underwent primary PTCA or stenting in the first 24 hours of AMI, with the target vessel being an occluded vein graft. Immediate results and major coronary events occurring up until hospital discharge were analyzed. RESULTS: During this period, 5,932 patients underwent primary PTCA or stenting; 158 (3% of the procedures were performed because of an acute vein graft occlusion. Stenting was performed in 74 (47% patients. Patients treated with stents had a higher success rate and lower mean residual stenosis compared with those who underwent primary balloon PTCA. The incidence of reinfarction and death were similar for stenting and balloon PTCA. CONCLUSION: Primary percutaneous treatment of AMI related to acute vein graft occlusion is still an uncommon practice. Primary stenting improved luminal diameter and offered higher rates of success; however, this strategy did not reduce the in-hospital reinfarction and death rate, compared with that occurring with PTCA treatment.

  17. Unintended Thermal Injuries from Radiofrequency Ablation: Organ Protection with an Angioplasty Balloon Catheter in an Animal Model

    Directory of Open Access Journals (Sweden)

    Martha-Grace Knuttinen

    2014-01-01

    Full Text Available Objectives: The aim of this study was to investigate a novel approach of using a balloon catheter as a protective device to separate liver from the diaphragm or nearby bowel during radiofrequency ablation (RFA of hepatic dome tumors in an animal model. Materials and Methods: All experimental procedures were approved by animal Institutional Review Board. Using a 3 cm RF needle electrode, 70 hepatic ablation zones were created using ultrasound in 7 pigs. 50 lesions were created using balloon interposition between liver and diaphragm; 20 lesions were created using the balloon device interposed posteriorly between liver and bowel. Additional 21 control lesions were performed. Animals were sacrificed immediately; diaphragm and bowel were then visually inspected and sectioned. Diaphragmatic and bowel injury was then classified according to the depth of thickness. Results: Control lesions caused full thickness injury, either to diaphragm or bowel. During ablation of lesions with balloon interposition, there was significantly less diaphragmatic injury, P < 0.001 and less bowel injury, P < 0.01. Conclusion: Using balloon interposition as a protective device has advantages over previous saline infusion or CO 2 insufflation, providing a safe way to expand percutaneous RFA of liver tumors located on the undersurface of the diaphragm. In addition, this method may be used in protection of other organs adjacent to areas being ablated.

  18. Drug-eluting versus plain balloon angioplasty for the treatment of failing dialysis access: Final results and cost-effectiveness analysis from a prospective randomized controlled trial (NCT01174472)

    Energy Technology Data Exchange (ETDEWEB)

    Kitrou, Panagiotis M., E-mail: panoskitrou@gmail.com [Department of Interventional Radiology, Patras University Hospital, School of Medicine, Rion 26504 (Greece); Katsanos, Konstantinos [Department of Interventional Radiology, Guy' s and St. Thomas’ Hospitals, NHS Foundation Trust, King' s Health Partners, London SE1 7EH (United Kingdom); Spiliopoulos, Stavros; Karnabatidis, Dimitris; Siablis, Dimitris [Department of Interventional Radiology, Patras University Hospital, School of Medicine, Rion 26504 (Greece)

    2015-03-15

    Highlights: •1-Year target lesion primary patency significantly higher after PCB application compared to plain balloon angioplasty in the failing dialysis access. •Significant difference in favor of PCB in cumulative primary patency of AVGs at 1 year. •No significant difference in cumulative primary patency of AVFs treated with PCB at 1 year. •Cost effectiveness analysis performed. •Paclitaxel-coated balloon angioplasty proves to be a cost-effective option for treating dialysis access. -- Abstract: Objective: To report the final results and cost-effectiveness analysis of a prospective randomized controlled trial investigating drug-eluting balloon (DEB) versus plain balloon angioplasty (BA) for the treatment of failing dialysis access ( (NCT01174472)). Methods: 40 patients were randomized to angioplasty with either DEB (n = 20) or BA (n = 20) for treatment of significant venous stenosis causing a failing dialysis access. Both arteriovenous fistulas (AVF) and synthetic arteriovenous grafts (AVG) were included. Angiographic follow up was scheduled every two months. Primary endpoints were technical success and target lesion primary patency at 1 year. Cumulative and survival analysis was performed. Incremental net benefit (INB) and incremental cost effectiveness ratio (ICER) were calculated and the cost-effectiveness acceptability curve (CEAC) was drawn. Results: Baseline variables were equally distributed between the two groups. At 1 year, cumulative target lesion primary patency was significantly higher after DEB application (35% vs. 5% after BA, p < 0.001). Overall, median primary patency was 0.64 years in case of DEB vs. 0.36 years in case of BA (p = 0.0007; unadjusted HR = 0.27 [95%CI: 0.13–0.58]; Cox adjusted HR = 0.23 [95%CI: 0.10–0.50]). ICER was 2198 Euros (€) per primary patency year of dialysis access gained. INB was 1068€ (95%CI: 31–2105€) for a willingness-to-pay (WTP) threshold of 5000€ (corresponding acceptability probability >97

  19. Surface modification of poly(ethylene terephthalate) angioplasty balloons with a hydrophilic poly(acrylamide-co-ethylene glycol) interpenetrating polymer network coating.

    Science.gov (United States)

    Park, S; Bearinger, J P; Lautenschlager, E P; Castner, D G; Healy, K E

    2000-09-01

    An interpenetrating polymer network (IPN) of poly(acrylamide-co-ethylene glycol) (p(AAm-co-EG)) hydrogel was covalently grafted to polyethylene terephthalate (PET) angioplasty balloons to increase surface hydrophilicity and improve lubricity. A 2-step graft polymerization protocol was followed to first polymerize and cross-link acrylamide onto the substrate with a photosensitizer and/or oxygen plasma pretreatment. The effects of varying photo-initiation and plasma exposure times were investigated separately and conjunctively using water contact angles to obtain optimal coating deposition parameters. A poly(ethylene glycol) network was then grafted by swelling the preexisting polyacrylamide network to allow inter-diffusion of the monomer and cross-linker, which were then polymerized by photo-initiation. When the photo-initiation time was long enough to reach near gelation, pretreatment of PET with oxygen plasma did not offer significant benefit. X-ray photoelectron spectroscopy confirmed the presence of both polymer layers, and composition depth profiles supported the assessment that an interpenetrating network was formed. Tensile testing and application of Weibull statistics on unmodified and modified films indicated that the surface modification approach did not significantly alter the mechanical integrity of the material. These findings indicate that a p(AAm-co-EG) coating can be effectively deposited on PET surfaces without compromising the structural integrity of the substrate.

  20. Factors influencing technical success and outcome of percutaneous balloon angioplasty in de novo native hemodialysis arteriovenous fistulas

    Energy Technology Data Exchange (ETDEWEB)

    Heye, Sam, E-mail: sam.heye@uzleuven.be [University Hospitals Leuven, Department of Radiology, Herestraat 49, 3000 Leuven (Belgium); Maleux, Geert, E-mail: geert.maleux@uzleuven.be [University Hospitals Leuven, Department of Radiology, Herestraat 49, 3000 Leuven (Belgium); Vaninbroukx, Johan, E-mail: johan.vaninbroukx@uzleuven.be [University Hospitals Leuven, Department of Radiology, Herestraat 49, 3000 Leuven (Belgium); Claes, Kathleen, E-mail: Kathleen.claes@uzleuven.be [University Hospitals Leuven, Department of Nephrology, Herestraat 49, 3000 Leuven (Belgium); Kuypers, Dirk, E-mail: dirk.kuypers@uzleuven.be [University Hospitals Leuven, Department of Nephrology, Herestraat 49, 3000 Leuven (Belgium); Oyen, Raymond, E-mail: raymond.oyen@uzleuven.be [University Hospitals Leuven, Department of Radiology, Herestraat 49, 3000 Leuven (Belgium)

    2012-09-15

    Objective: To determine predictors of technical success, dysfunction recurrence and patency after percutaneous transluminal angioplasty (PTA) of de novo dysfunctional hemodialysis arteriovenous fistulas (AVFs). Methods: Retrospective analysis of first time PTA of 167 AVF in 162 patients (100 men, 66 ± 13 years). Anatomical (location, length, grade and number of stenoses) and clinical variables (sex, age, prior AVF, diabetes mellitus and AVF age, side and location) were reviewed. Results: 217 stenoses or segmental occlusions were treated. Technical success rate (84.4%) was higher in radiocephalic AVF compared to brachial artery–median vein AVF (p = 0.030) and was negatively correlated with initial stenosis (p = 0.049). Dysfunction recurrence was seen in 52.7% and correlated negatively with technical success (p = 0.013) and AVF age (p = 0.008). Early dysfunction (within 6 months) was negatively correlated with AVF age (p = 0.016) and positively with diabetes (p = 0.003). Higher AVF age resulted in higher primary (p = 0.005) and secondary patency rates (p = 0.037–0.005). Conclusions: Technical success of PTA in hemodialysis AVF is affected by AVF type and initial stenosis and has significant effect on dysfunction recurrence, but not on AVF longevity. Younger AVF has increased risk for (early) recurrent dysfunction and lower patency rates. Patients with diabetes mellitus have higher risk for early dysfunction.

  1. Myxomavirus anti-inflammatory chemokine binding protein reduces the increased plaque growth induced by chronic Porphyromonas gingivalis oral infection after balloon angioplasty aortic injury in mice.

    Directory of Open Access Journals (Sweden)

    Alexandra R Lucas

    Full Text Available Thrombotic occlusion of inflammatory plaque in coronary arteries causes myocardial infarction. Treatment with emergent balloon angioplasty (BA and stent implant improves survival, but restenosis (regrowth can occur. Periodontal bacteremia is closely associated with inflammation and native arterial atherosclerosis, with potential to increase restenosis. Two virus-derived anti-inflammatory proteins, M-T7 and Serp-1, reduce inflammation and plaque growth after BA and transplant in animal models through separate pathways. M-T7 is a broad spectrum C, CC and CXC chemokine-binding protein. Serp-1 is a serine protease inhibitor (serpin inhibiting thrombotic and thrombolytic pathways. Serp-1 also reduces arterial inflammation and improves survival in a mouse herpes virus (MHV68 model of lethal vasculitis. In addition, Serp-1 demonstrated safety and efficacy in patients with unstable coronary disease and stent implant, reducing markers of myocardial damage. We investigate here the effects of Porphyromonas gingivalis, a periodontal pathogen, on restenosis after BA and the effects of blocking chemokine and protease pathways with M-T7 and Serp-1. ApoE-/- mice had aortic BA and oral P. gingivalis infection. Arterial plaque growth was examined at 24 weeks with and without anti-inflammatory protein treatment. Dental plaques from mice infected with P. gingivalis tested positive for infection. Neither Serp-1 nor M-T7 treatment reduced infection, but IgG antibody levels in mice treated with Serp-1 and M-T7 were reduced. P. gingivalis significantly increased monocyte invasion and arterial plaque growth after BA (P<0.025. Monocyte invasion and plaque growth were blocked by M-T7 treatment (P<0.023, whereas Serp-1 produced only a trend toward reductions. Both proteins modified expression of TLR4 and MyD88. In conclusion, aortic plaque growth in ApoE-/- mice increased after angioplasty in mice with chronic oral P. gingivalis infection. Blockade of chemokines, but not

  2. Percutaneous Balloon Angioplasty for Severe Native Aortic Coarctation in Young Infants Less Than 6 Months: Medium-to Long-term Follow-up

    Institute of Scientific and Technical Information of China (English)

    Lan He; Fang Liu; Lin Wu; Chun-Hua Qi; Li-Feng Zhang; Guo-Ying Huang

    2015-01-01

    Background:Although balloon angioplasty (BA) has been performed for more than 20 years,its use as a treatment for native coarctation of the aorta (CoA) during childhood,especially in young infants,remains controversial.This study aimed to assess the effects and potential role of percutaneous transcatheter BA for native CoA as an alternative therapy to surgical repair in young infants.Methods:The 37 patients aged from 6 days to 6 months with severe CoA in congestive heart failure or circulatory shock were admitted for BA.Patient's weight ranged from 2.4 to 6.1 kg.All 37 patients were experiencing cardiac dysfunction,and eight patients were in cardiac shock with severe metabolic acidosis.Eleven patients had an isolated CoA,whereas the others had a CoA associated with other cardiac malformations.Cardiac catheterization and aortic angiography were performed under general anesthesia with intubation.Transfemoral arterial approaches were used for the BA.The size of the balloon ranged from 3 mm × 20 mm to 8 mm × 20 mm,and a coronary artery balloon catheter was preferred over a regular peripheral vascular balloon catheter.Results:The femoral artery was successfully punctured in all but one patient,with that patient undergoing a carotid artery puncture.The systolic peak pressure gradient (PG) across the coarctation was 41.0 ± 16.0 mmHg (range 13-76 mmHg).The mean diameter of the narrowest coarctation site was 1.7 ± 0.6 mm (range 0.5-2.8 mm).All patients had successful dilation;the PG significantly decreased to 13.0 ± 1 1.0 mmHg (range 0-40 mmHg),and the diameter of coarctation significantly improved to 3.8 ± 0.9 mm (range 2.5-5.3 mm).No intraoperative complications occurred for any patients.However,in one case that underwent a carotid artery puncture,a giant aneurysm formed at the puncture site and required surgical repair.The following observations were made during the follow-up period from 6-month to 7-year:(1) The PG across the coarctation measured by

  3. High prevalence of severe coronary artery disease in elderly patients with non-operable chronic thromboembolic pulmonary hypertension referred for balloon pulmonary angioplasty

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    Marek Roik

    2016-11-01

    Full Text Available Introduction : Balloon pulmonary angioplasty (BPA is a new emerging catheter-based alternative treatment option for patients with inoperable chronic thromboembolic pulmonary hypertension (CTEPH. Aim : To show that all elderly CTEPH patients referred for BPA are at higher risk of obstructive coronary artery disease and that, in daily practice, they should undergo invasive coronary angiography. Material and methods : Eleven patients at the age of at least 65 years (6 males, 5 females, 77.2 ±5.9 years with confirmed non-operable type II or type III CTEPH, considered for BPA, underwent elective coronary angiography. Severe obstructive coronary artery disease (CAD was diagnosed when stenosis of left main coronary artery ≥ 50% or stenosis of ≥ 70% of epicardial arteries was angiographically confirmed. We also screened for CAD consecutive age- and sex-matched 114 PE survivors (52 males, 62 females, 74.8 ±7.2 years with excluded CTEPH. Results : Severe CAD was more frequent in elderly patients with non-operable type II or type III CTEPH candidates for BPA than in elderly acute PE survivors with excluded CTEPH (54.5% vs. 16.7%, p < 0.01, and therefore elderly CTEPH patients referred for BPA were at higher risk of CAD (OR = 5.9, 95% CI: 1.64–21.46, p = 0.007 when compared to elderly survivors after acute PE with excluded CTEPH. Conclusions : All elderly CTEPH patients referred for BPA are at higher risk of severe CAD and should routinely undergo invasive coronary angiography before BPA.

  4. Cost-effectiveness of paclitaxel-coated balloon angioplasty and paclitaxel-eluting stent implantation for treatment of coronary in-stent restenosis in patients with stable coronary artery disease.

    Science.gov (United States)

    Bonaventura, Klaus; Leber, Alexander W; Sohns, Christian; Roser, Mattias; Boldt, Leif-Hendrik; Kleber, Franz X; Haverkamp, Wilhelm; Dorenkamp, Marc

    2012-07-01

    Recent studies have demonstrated the safety and efficacy of drug-coated balloon (DCB) angioplasty for the treatment of coronary in-stent restenosis (ISR). The cost-effectiveness of this practice is unknown. A Markov state-transition decision analytic model accounting for varying procedural efficacy rates, complication rates, and cost estimates was developed to compare DCB angioplasty with drug-eluting stent (DES) placement in patients with bare-metal stent (BMS)-ISR. Data on procedural outcomes associated with both treatment strategies were derived from the literature, and the cost analysis was conducted from a health care payer perspective. Effectiveness was expressed as life-years gained. In the base-case analysis, initial procedure costs amounted to €3,604.14 for DCB angioplasty and to €3,309.66 for DES implantation. Over a 12-month time horizon, the DCB strategy was found to be less costly (€4,130.38 vs. €5,305.30) and slightly more effective in terms of life expectancy (0.983 vs. 0.976 years) than the DES strategy. Extensive sensitivity analyses indicated that, in comparison with DES implantation, the cost advantage of the DCB strategy was robust to clinically plausible variations in the values of key model input parameters. The variables with the greatest impact on base-case results were the duration of dual antiplatelet therapy with acetylsalicylic acid and clopidogrel after DCB angioplasty, the use of generic clopidogrel, and variations in the costs associated with the DCB device. DCB angioplasty is a cost-effective treatment option for coronary BMS-ISR. The higher initial costs of DCB are more than offset by later cost-savings, predominantly as a result of reduced medication costs.

  5. Transradial artery coronary angioplasty.

    Science.gov (United States)

    Kiemeneij, F; Laarman, G J; de Melker, E

    1995-01-01

    This study explored the feasibility and safety of percutaneous coronary balloon angioplasty (PTCA) with miniaturized PTCA equipment via the radial artery. Coronary angioplasty (PTCA) via the femoral or brachial arteries may be associated with rare vascular complications such as bleeding and damage to the artery and adjacent structures. It was postulated that PTCA via the radial artery with miniaturized angioplasty equipment is feasible and that no major puncture site-related complications occur because hemostasis is obtained easily and because no major structures are near the radial artery. With double blood supply to the hand, radial artery occlusion is well tolerated. In 100 patients with collateral blood supply to the right hand, PTCA was attempted with 6F guiding catheters and rapid-exchange balloon catheters for exertional angina (87 patients) or nonexertional angina (13 patients). Angioplasty was attempted in 122 lesions (type A n = 67 [55%], Type B n = 37 [30%], and type C n = 18 [15%]). Pre- and post-PTCA computerized quantitative coronary analysis was performed. Radial artery function and structure were assessed clinically and with Doppler and two-dimensional ultrasound on the day of discharge. Coronary catheterization via the radial artery was successful in 94 patients (94%). The 6 remaining patients had successful PTCA via the femoral artery (n = 5) or the brachial artery (n = 1). Procedural success (120 of 122 lesions) was achieved in 92 patients (98%) via the radial artery and in 98 patients of the total study population.(ABSTRACT TRUNCATED AT 250 WORDS)

  6. Laser angioplasty for cardiovascular disease

    Science.gov (United States)

    Okada, Masayoshi

    2005-07-01

    Recently, endovascular interventions such as balloon angioplasty, atherectomy and the stenting method, except for conventional surgery have been clinically employed for the patients with atheromatous plaques of the peripheral- and the coronary arteries, because the number of patients with arteriosclerosis is now increasing in the worldwide. Among these procedures, restenoses after endovascular interventions have been remarkably disclosed in 20-40 % of the patients who underwent percutaneous coronary interventions. Thus, there are still some problems in keeping long-term patency by means of endovascular techniques such as balloon angioplasty and atherectomy (1, 2). For reduction of these problems , laser angioplasty using Argon laser was applied experimentally and clinically. Based on excellent experimental studies, laser was employed for 115 patients with stenotic ,or obstructive lesions occluding more thasn 75 % of the peripheral and the coronary arteries angiographycally.

  7. MYOCARDIAL PROTECTION DURING CORONARY ANGIOPLASTY WITH AUTOPERFUSION AND FORCED PERFUSION - AN IN-VITRO COMPARISON

    NARCIS (Netherlands)

    DEMUINCK, ED; VERKERKE, BJ; RAKHORST, G; LIE, KI

    1994-01-01

    During coronary angioplasty, perfusion distal to the inflated angioplasty balloon can be maintained with autoperfusion balloon catheters and coronary perfusion pumps. The blood flow rates through the autoperfusion balloon catheters and the flow rates achieved with a perfusion pump were compared in v

  8. A randomized trial assessing the effect of coumarins started before coronary angioplasty on restenosis: results of the 6-month angiographic substudy of the Balloon Angioplasty and Anticoagulation Study (BAAS).

    Science.gov (United States)

    ten Berg, Jurriën M; Kelder, Johannes C; Suttorp, Maarten Jan; Verheugt, Freek W A; Plokker, H W Thijs

    2003-01-01

    Thrombus formation during coronary angioplasty may play a role in the restenosis process. The effect of pretreatment with coumarins on 6-month angiographic outcome was studied. In addition, the effect of "optimal" anticoagulation, defined as an international normalized ratio >70% of the follow-up time in the target range, was studied. A total of 261 patients were assigned to aspirin alone (ASA group) and 270 patients to aspirin plus coumarins started 1 week before the procedure (coumarin group). The mean international normalized ratio was 2.7 +/- 1.2 at the start of the procedure and 3.1 +/- 0.5 during follow up. Quantitative coronary analysis was performed on 301 lesions in the ASA group and of 297 lesions in the coumarin group. At 6 months, the minimal luminal diameter was similar in the ASA and coumarin groups. Optimal anticoagulation, however, was an independent predictor of a larger minimal luminal diameter at follow up (P =.01). Overall, coumarins do not improve angiographic outcome 6 months after coronary angioplasty.

  9. Local hemodynamic changes caused by main branch stent implantation and subsequent virtual side branch balloon angioplasty in a representative coronary bifurcation.

    Science.gov (United States)

    Williams, Andrew R; Koo, Bon-Kwon; Gundert, Timothy J; Fitzgerald, Peter J; LaDisa, John F

    2010-08-01

    Abnormal blood flow patterns promoting inflammation, cellular proliferation, and thrombosis may be established by local changes in vessel geometry after stent implantation in bifurcation lesions. Our objective was to quantify altered hemodynamics due to main vessel (MV) stenting and subsequent virtual side branch (SB) angioplasty in a coronary bifurcation by using computational fluid dynamics (CFD) analysis. CFD models were generated from representative vascular dimensions and intravascular ultrasound images. Time-averaged wall shear stress (TAWSS), oscillatory shear index (OSI), and fractional flow reserve (FFR) were quantified. None of the luminal surface was exposed to low TAWSS (stenting introduced eccentric areas of low TAWSS along the lateral wall of the MV. Virtual SB angioplasty resulted in a more concentric region of low TAWSS in the MV distal to the carina and along the lateral wall of the SB. The luminal surface exposed to low TAWSS was similar before and after virtual SB angioplasty (rest: 43% vs. 41%; hyperemia: 18% vs. 21%) and primarily due to stent-induced flow alterations. Sites of elevated OSI (>0.1) were minimal but more impacted by general vessel geometry established after MV stenting. FFR measured at a jailed SB was within the normal range despite angiographic stenosis of 54%. These findings indicate that the most commonly used percutaneous interventional strategy for a bifurcation lesion causes abnormal local hemodynamic conditions. These results may partially explain the high clinical event rates in bifurcation lesions.

  10. Balloon angioplasty for native coarctation in children: one year follow-up results%球囊扩张成形术治疗儿童主动脉缩窄一年随访

    Institute of Scientific and Technical Information of China (English)

    何岚; 吴琳; 刘芳; 齐春华; 陆颖; 张丹艳; 黄国英

    2014-01-01

    Objective Balloon angioplasty is an alternative to surgical repair for coarctation of the aorta in children.However,its role in the treatment of neonates and infants younger than 3 months old remains controversial.The purpose of this study was to evaluate the efficacy and safety of balloon angioplasty for native coarctation by comparing children in different age groups.Method This is a retrospective clinical study including 37 children treated with balloon angioplasty for native coarctation from January 2006 to December 2012.A total of 37 patients consisting of 26 boys and 11 girls underwent the procedure,with median age 10 months (range from 7 days to 6 years) and the mean body weight was 6.3 (2.5-17.0) kg.The indication of the procedure includes discrete native coarctation without aortic arch hypoplasia and a peak-to-peak systolic pressure gradient > 20 mmHg (1 mmHg =0.133 kPa) across aortic coarctation.During one year follow-up,the approach artery injury,recoarctation and aneurysm formation were particularly assessed.Result We classified these patients into two groups according to their age.Group A consisted of 25 patients younger than 3 months and Group B of 12 patients older than 3 months.There was no significant difference between the two groups in systolic pressure gradient before balloon angioplasty (P > 0.05).The mean peak systolic gradient decreased from (38 ± 18) mmHg to (12 ± 11) mmHg immediately after angioplasty in group A and from (47 ±18) to (17 ± 12) mmHg in group B (P =0.000 for both).Meanwhile,the mean diameter of the coarctation segment increased from (1.8 ± 0.7) to (3.7 ± 1.1) mm after angioplasty in group A and from (2.6 ± 1.5) to (5.5 ± 1.8) mm in group B (both P =0).The initial successful balloon angioplasty (immediate postangioplasty peak pressure gradient < 20 mmHg) was achieved in all the 37 patients; 32 patients (86.5%) have been followed up for one year.Approach arterial complications occurred in 3 patients (9.4

  11. Stent graft versus balloon angioplasty for failing dialysis access grafts: a long-awaited advance in the treatment of permanent hemodialysis access.

    Science.gov (United States)

    Dolmatch, Bart L

    2010-01-01

    Arteriovenous grafts (AVGs) for hemodialysis have a high failure rate, often due to the development of stenosis at the graft-to-vein anastomosis. Angioplasty (PTA) has been used for over two decades to treat AVG stenosis, with good technical success but limited AVG patency. Results of a prospective multi-center randomized trial, comparing stent graft to PTA in AVGs, has demonstrated superior access circuit patency for the stent graft group. Recent publication of this clinical study brings us into an exciting new era of dialysis access management using covered stents to improve durability of catheter-based therapy.

  12. Regional differences in elastic recoil after percutaneous transluminal coronary angioplasty: a quantitative angiographic study

    NARCIS (Netherlands)

    B.J.W.M. Rensing (Benno); B.H. Strauss (Bradley); P.W.J.C. Serruys (Patrick); W.R.M. Hermans (Walter)

    1991-01-01

    textabstractThe immediate result of percutaneous transluminal coronary angioplasty is influenced by both plastic and elastic changes of the vessel wall. To evaluate the amount of elastic recoil after coronary balloon angioplasty, the minimal luminal cross-sectional area of the largest balloon used a

  13. T-shaped angioplasty with apex puncture of thrombosed looped hemodialysis grafts.

    Science.gov (United States)

    Oh, Jung Suk; Choi, Byung Gil; Chun, Ho Jong; Lee, Hae Giu

    2013-03-01

    This study is a retrospective evaluation of an alternative technique for angioplasty of thrombosed loop hemodialysis grafts through a single vascular access. This technique can provide balloon angioplasty to the puncture site without any additional vascular accesses by using a T-shaped balloon catheter and can simplify thrombectomy procedures. Copyright © 2013 SIR. Published by Elsevier Inc. All rights reserved.

  14. Low-pressure

    Energy Technology Data Exchange (ETDEWEB)

    Baker, Richard [Membrane Technology And Research, Inc., Newark, CA (United States); Kniep, Jay [Membrane Technology And Research, Inc., Newark, CA (United States); Hao, Pingjiao [Membrane Technology And Research, Inc., Newark, CA (United States); Chan, Chi Cheng [Membrane Technology And Research, Inc., Newark, CA (United States); Nguyen, Vincent [Membrane Technology And Research, Inc., Newark, CA (United States); Huang, Ivy [Membrane Technology And Research, Inc., Newark, CA (United States); Amo, Karl [Membrane Technology And Research, Inc., Newark, CA (United States); Freeman, Brice [Membrane Technology And Research, Inc., Newark, CA (United States); Fulton, Don [Membrane Technology And Research, Inc., Newark, CA (United States); Ly, Jennifer [Membrane Technology And Research, Inc., Newark, CA (United States); Lipscomb, Glenn [Membrane Technology And Research, Inc., Newark, CA (United States); Lou, Yuecun [Membrane Technology And Research, Inc., Newark, CA (United States); Gogar, Ravikumar [Membrane Technology And Research, Inc., Newark, CA (United States)

    2015-01-29

    This final technical progress report describes work conducted by Membrane Technology and Research, Inc. (MTR) for the Department of Energy (DOE NETL) on development of low-pressure membrane contactors for carbon dioxide (CO2) capture from power plant flue gas (award number DE-FE0007553). The work was conducted from October 1, 2011 through September 30, 2014. The overall goal of this three-year project was to build and operate a prototype 500 m2 low-pressure sweep membrane module specifically designed to separate CO2 from coal-fired power plant flue gas. MTR was assisted in this project by a research group at the University of Toledo, which contributed to the computational fluid dynamics (CFD) analysis of module design and process simulation. This report details the work conducted to develop a new type of membrane contactor specifically designed for the high-gas-flow, low-pressure, countercurrent sweep operation required for affordable membrane-based CO2 capture at coal power plants. Work for this project included module development and testing, design and assembly of a large membrane module test unit at MTR, CFD comparative analysis of cross-flow, countercurrent, and novel partial-countercurrent sweep membrane module designs, CFD analysis of membrane spacers, design and fabrication of a 500 m2 membrane module skid for field tests, a detailed performance and cost analysis of the MTR CO2 capture process with low-pressure sweep modules, and a process design analysis of a membrane-hybrid separation process for CO2 removal from coal-fired flue gas. Key results for each major task are discussed in the report.

  15. Novel paclitaxel-coated angioplasty balloon catheter based on cetylpyridinium salicylate: Preparation, characterization and simulated use in an in vitro vessel model

    Energy Technology Data Exchange (ETDEWEB)

    Petersen, Svea, E-mail: svea.petersen@uni-rostock.de [Institute for Biomedical Engineering, University of Rostock, Friedrich-Barnewitz-Straße 4, 18119 Rostock (Germany); Kaule, Sebastian [Institute for Biomedical Engineering, University of Rostock, Friedrich-Barnewitz-Straße 4, 18119 Rostock (Germany); Stein, Florian [Institute for Chemistry, Analytical and Technical Chemistry University of Rostock, Albert-Einstein-Straße 3a, 18059 Rostock (Germany); Minrath, Ingo; Schmitz, Klaus-Peter [Institute for Biomedical Engineering, University of Rostock, Friedrich-Barnewitz-Straße 4, 18119 Rostock (Germany); Kragl, Udo [Institute for Chemistry, Analytical and Technical Chemistry University of Rostock, Albert-Einstein-Straße 3a, 18059 Rostock (Germany); Sternberg, Katrin [Institute for Biomedical Engineering, University of Rostock, Friedrich-Barnewitz-Straße 4, 18119 Rostock (Germany)

    2013-10-15

    Drug-coated balloons (DCB), which have emerged as therapeutic alternative to drug-eluting stents in percutaneous cardiovascular intervention, are well described with regard to clinical efficiency and safety within a number of clinical studies. In vitro studies elucidating the correlation of coating method and composition with DCB performance are however rare but considered important for the understanding of DCB requirements and the improvement of established DCB. In this context, we evaluated the applicability of a pipetting, dip-coating, and spray-coating process for the establishment of DCB based on paclitaxel (PTX) and the ionic liquid cetylpyridinium salicylate (Cetpyrsal) as novel innovative additive in three different compositions. Among tested methods and compositions, the pipetting process with 50 wt.% PTX resulted in most promising coatings as drug load was less controllable by the other processes and higher PTX contents led to considerable drug crystallization, as visualized by electron microscopy, accelerating PTX loss during short-term elution. Applying these conditions, homogeneous coatings could be applied on balloon catheter, whose simulated use in an in vitro vessel model revealed percental drug losses of 36 and 28% during transit and percental drug transfers of 12 and 40% under expansion for coatings applied in expanded and folded balloon condition, respectively. In comparison to literature values, these results support the high potential of Cetpyrsal as novel DCB matrix regarding low drug loss and efficient drug transfer. - Highlights: • We provide detailed in vitro data for definition of DCB coating requirements. • An in vitro vessel model for evaluating drug delivery from DCB is presented. • Innovative ionic liquid-based coatings for DCB are developed. • The coating shows low drug loss and efficient drug transfer.

  16. Angioplasty for coarctation in different aged patients.

    Science.gov (United States)

    Walhout, Ronald J; Lekkerkerker, Jaco C; Ernst, Sjef M P G; Hutter, Paul A; Plokker, Thijs H W M; Meijboom, Erik J

    2002-07-01

    Differences in the indication and outcome of balloon angioplasty for coarctation in children and adults have not been elucidated sufficiently. The results of balloon angioplasty for coarctation are compared between pediatric and adult age groups. Balloon angioplasty for coarctation of the aorta was performed in 85 patients who were classified according to age and native coarctation/recoarctation. Groups A (patients aged or =16 years, n = 17) included patients with native coarctations. Groups rCoA A (patients aged or =16 years, n = 3) included patients with recoarctations. Follow-up included 2-dimensional Doppler scanning echocardiography and additional angiography or magnetic resonance imaging. Gradient reductions in groups were compared by use of the independent-samples t test. Kaplan-Meier and log-rank analyses were performed as a means of comparing long-term outcome. No mortality occurred. Immediate success was equal in groups A, B, and rCoA A (94%). Dilatation was unsuccessful in 2 patients in group rCoA B. Pressure gradients decreased 23 mm Hg in group A, 31 mm Hg in group B, 18 mm Hg in group rCoA A, and 11 mm Hg in group rCoA B. Pressure gradient drops, compared between groups A and B, showed a significant difference (P <.001). The length of hospital stay ranged from 12 to 48 hours. The period of follow-up ranged from 6 months to 12 years (mean, 4.9 years). Kaplan-Meier curves of groups A and B are not different, as determined by means of log-rank analysis. No aneurysm formation was encountered. The results of balloon angioplasty for native coarctation in both selected children and adults are excellent. In recoarctation, we recommend balloon angioplasty in the pediatric patients.

  17. 球囊血管成形术对血浆TNF-α、ET水平及局部血管组织ET-IR的影响%Effect of balloon angioplasty on plasma ET and TNF-α levels and tissue endothe lin immunoreactivity in experimental atherosclerotic rabbits

    Institute of Scientific and Technical Information of China (English)

    杜荣增; 吴宗贵; 黄佐; 黄高忠; 张国元

    2001-01-01

    目的 :通过建立兔髂动脉粥样硬化(AS)模型,观察球囊 血管成形术(BA)对血浆肿瘤坏死因子α(TNF-α)、内皮素(ET)水平及局部血管组织E T免疫反应性(ET-IR)的影响。方法:20只新西兰雄性大白兔经高脂饲 料喂养至少8周造成AS,然后进行髂动脉BA,18只兔获得成功。检测了BA前、即刻及24 h后 血浆ET和TNF-α水平,ET采用放射免疫法测定,TNF-α采用生物活性法测定。同时,应用 免疫组织化学技术评价血管组织ET-IR。结果:BA前后即刻:血浆ET水 平(pg/ml)分别为76.4±13.58和92.67±11.38(P0.05);而血浆TNF-α水平(U/ml)分别为31.35±6.23和56.26±7.37(P 0.05)。 BA后局部髂动脉血管壁ET-IR较未经BA的髂动脉明显增加。结论:BA 后血浆ET、TNF-α水平升高及局部血管壁ET-IR增加可能与局部血管内膜损伤有关,提示E T、TNF-α可能参与了PTCA后急性冠脉收缩及再狭窄过程。%Objective: To assess the effect of balloon angiopl asty on circulating endothelin (ET) and TNF-α levels and tissue endothelin in experimental atherosclerosis in rabbits. Methods: After 20 New Z ealand rabbits had a high cholesterol diet for at least 8 weeks, successful ball oon angioplasty was performed in rihgt iliac arteries in 18 rabbits. Circulatin g levels of ET and TNF-α were measured before as well as immediately and 24 h after balloon angioplasty. Tissue endothelin immunoreactivity in atherosclerotic iliac artery wall after balloon angioplasty was assessed by immunohistochemica l technique. Results: Plasma levels of ET and TNF-α were signi ficantly increased immediately after ballon angioplasty (76.40±13.58)pg/ml vs (92.67±11.38) pg/ml and (31.35±6.23) U/ml vs (56.26±7.37) U/ml, resp ectively (P0.05). T issue endothelin immunoreactiuvity was markedly increased in right iliac artery wall after balloon angioplasty than that in opposite iliac artery wall. Conclusion: The increase of plasma

  18. 依达拉奉防治大鼠颈动脉球囊成形术后血管再狭窄%Experimental study on edaravone in prevention of restenosis in rat common carotid balloon angioplasty

    Institute of Scientific and Technical Information of China (English)

    周海武; 徐平

    2008-01-01

    Objective To investigate edaravane in prevention of restenosis in rat common catery arteries balloon angioplasty and the possible mechanism of this process. Methods Forty male SD rats were randomly divided into 2 groups: treatment group (whose intima was injured by balloon and was given edaravone 3 mg/kg by peritoneal injection, bid) and control group (whose intima was injured by ballon and was given the same volume NS as edaravone). 1, 3, 7, 14 and 28 days after angioplasty, rats were killed and the local arteries were sectioned for analysis of pathological morphology and the expression of matrix metalloproteinase-2 (MMP-2) analyzed by immunohistochemistry. Results Small amounts of smooth muscle cell appeared at the intima of blood vessel 3 days after the artery injured by balloon. Consecutive intima was formed 7 days after artery injury. The intima was even or uneven thickened and the lumen of artery was significant stenosed 14 and 28 days afterwards. In the control group, the intimal area reached (0.240±0.043) mm2, the intima hyperplasy index were 0.52±0.06, stenosis ratio were 30%±9% 14 days afterwards. The intimal area were (0.420±0.063 )mm2, the intima hyperplasy index were 0.67± 0.07, stenosis ratio were 54%±9% on day 28. In the treatment group, the intimal area were (0.063± 0.025)mm2, the intima hyperplasy index were 0.24±0.07, stenosis ratio were 8%±3% after 14 days. The intimal area were (0.116±0.023) mm2, the intima hyperplasy index were 0.38±0.05, stenosis ratio were 16%±4% after 28 days. Compared with control group at the same time, the intimal area (F values were 50.488 and 81.119 respectively, P < 0.05 ), the intima hyperplasy index ( F values were 41.743 and 48.122 respectively, P<0.05) and stenosis ratio (F values were 24.221 and 81.119 respectively, P< 0.05) were decreased in treatment group. The expressions of MMP-2 raised after balloon injury. In control group, the expressions of MMP-2 were 27.16%±7.15% after 3 days, 22.59%±6

  19. Angioplasty and stent placement - heart

    Science.gov (United States)

    ... angioplasty; Coronary artery angioplasty; Percutaneous transluminal coronary angioplasty; Heart artery dilatation ... to carefully guide the catheter up into your heart and arteries. Dye will be injected into your ...

  20. Matrix metalloproteinase inhibition reduces adventitial thickening and collagen accumulation following balloon dilation

    NARCIS (Netherlands)

    Sierevogel, MJ; Velema, E; van der Meer, FJ; Nijhuis, MO; de Kleijn, DPV; Borst, C; Pasterkamp, G

    2002-01-01

    Objective: Constrictive arterial remodeling following balloon angioplasty has been related to adventitial collagen accumulation and subsequent thickening and can be prevented by matrix ructalloprotemase (MMP) inhibition. Following balloon dilation, we examined the effect of MMP inhibition on colla-e

  1. Histopathology of human laser thermal angioplasty recanalization.

    Science.gov (United States)

    White, R A; White, G H; Vlasak, J; Fujitani, R; Kopchok, G E

    1988-01-01

    Laserprobe thermal-assisted balloon, angioplasty (LTBA) has demonstrated promising initial clinical results in recanalizing stenotic or occluded superficial femoral and popliteal arteries. Over the past year we have obtained six specimens of laserprobe thermal (LT) and LTBA treated total occlusions (avg. length 12 cm) for histopathologic examination from patients who were treated for limb salvage. Three tissue specimens were obtained acutely, and one was obtained at 6, 8, and 13 days, respectively, after laser angioplasty at the time of revision for complications or failed procedures. Serial histologic sections of the treated LT segments demonstrated recanalization of atherosclerotic lesions to approximately 60-70% of the probe diameter. The LT channels were lined by a thin layer of carbonized or coagulated tissue and several layers of cell necrosis. The histology of the thermal injury was similar regardless of whether it was produced by the heated metal cap or by free argon laser energy. Stellate balloon angioplasty fractures were frequently filled with thrombus. Analysis of these human LT and LTBA specimens revealed that the thermal device produces a confined injury through the path of least resistance. Balloon dilatation produces fragmented cracks in the vessel wall, which appear to be more thrombogenic than the carbonized LT surface. With improved guidance methods, LTBA shows potential for continuing development.

  2. Has multivessel angioplasty displaced surgical revascularization?

    Science.gov (United States)

    King, S B; Ivanhoe, R J

    1990-01-01

    Over the years, PTCA has been proved a safe and effective therapy for single-vessel CAD. Given the record of favorable results for single-vessel angioplasty, the extension of angioplasty to multivessel CAD soon followed. The successful application of PTCA to multivessel disease has been facilitated by developments in balloon, guidewire, and guide catheter technology. Success rates have been satisfactory, and complications have remained acceptable. Furthermore, as an outgrowth of an understanding of the mechanism and effect of PTCA, guidelines have been developed to aid case selection. As emphasized earlier, these guidelines should weigh heavily in deciding whether to select PTCA as a treatment modality. Presently, in our opinion, PTCA has not yet completely displaced surgery for multivessel CAD. Surgical standby is required for safe PTCA, because emergency surgery can be lifesaving and limit myocardial infarction after failed angioplasty. It is doubtful that surgery will ever relinquish its position as the treatment of choice for left main coronary artery disease. Nor will elective surgery find wide application in single-vessel disease. Whether one mode of revascularization will emerge as the most efficacious for multivessel disease related to long-term survival, limitation of cardiac events, and cost will be addressed in the analysis of the ongoing randomized trials of surgery versus angioplasty. Andreas Gruentzig established that it was possible to work within the coronary artery in an alert and comfortable patient. Interventional cardiology has experienced rapid technologic growth. Many patients formerly treated with bypass surgery can be managed effectively with angioplasty. If effective bail-out methods for acute closure are proven effective and restenosis is limited to a small percentage of patients, angioplasty in some form will further displace CABG. Until those ultimate goals are achieved, the value of angioplasty compared with bypass surgery must rest

  3. Segmentally enclosed thrombolysis in percutaneous transluminal angioplasty for femoropopliteal occlusions

    DEFF Research Database (Denmark)

    Jørgensen, B; Tønnesen, K H; Nielsen, J D;

    1991-01-01

    Segmentally enclosed thrombolysis (SET) was performed immediately following 34 percutaneous transluminal angioplasties (PTAs) for femoropopliteal occlusions. The dilated segment was sealed off with a double balloon catheter, and recombinant tissue plasminogen activator (rt-PA) 1 mg/ml and heparin...

  4. Distal coronary hemoperfusion during percutaneous transluminal coronary angioplasty

    NARCIS (Netherlands)

    Muinck, Ebo Derk de

    1994-01-01

    In this thesis several aspects of passive and active coronary perfusion during coronary angioplasty are investigated. The autoperfusion balloon catheters that were evaluated are the Stack® and the RX-60® catheters (Advanced Cardiovascular Systems, inc., Santa Clara, California, U.S.A). The coronary

  5. Distal coronary hemoperfusion during percutaneous transluminal coronary angioplasty

    NARCIS (Netherlands)

    Muinck, Ebo Derk de

    1994-01-01

    In this thesis several aspects of passive and active coronary perfusion during coronary angioplasty are investigated. The autoperfusion balloon catheters that were evaluated are the Stack® and the RX-60® catheters (Advanced Cardiovascular Systems, inc., Santa Clara, California, U.S.A). The coronary

  6. Thermal laser-assisted angioplasty of renal artery stenosis for renovascular hypertension.

    Science.gov (United States)

    Tani, M; Mizuno, K; Midorikawa, H; Igari, T; Egawa, M; Niimura, S; Fukuchi, S; Hoshino, S

    1993-01-01

    Percutaneous transluminal laser-assisted angioplasty of a renal artery stenosis was performed in a 16-year-old woman with renovascular hypertension. The stenotic portion of the renal artery was predilated by delivering Nd-YAG laser energy to the terminal tip of a laser catheter. Although the luminal diameter did not increase sufficiently with laser angioplasty alone, it allowed passage of the balloon catheter and subsequent successful balloon angioplasty. Immediately after dilatation, the patient's blood pressure fell to normal, and plasma renin activity decreased. There were no serious complications. Thermal laser angioplasty seems to be an effective adjunct technique for the treatment of severe renal artery stenosis which does not allow initial passage of a balloon catheter.

  7. Provisional stenting in the real world: results in 1058 consecutive patients undergoing percutaneous coronary angioplasty.

    Science.gov (United States)

    Ten Berg, Jurriën M; Kelder, Johannes C; Suttorp, Maarten Jan; Plokker, Thijs HW

    2001-09-01

    OBJECTIVE: To study a strategy of aggressive coronary balloon angioplasty with provisional stenting in allcomers. In randomized trials, stenting has improved the outcome of patients undergoing coronary intervention. However, whether these results hold up in clinical practice is largely unknown. Furthermore, the results of balloon angioplasty have also improved dramatically. It is therefore essential to evaluate the current results of balloon angioplasty and to assess whether stents are required in all patients. METHODS: The authors prospectively studied the occurrence of death, myocardial infarction (MI) and target lesion revascularization (TLR) of a large consecutive group of patients undergoing aggressive balloon angioplasty with provisional stenting. None of the patients received a platelet glycoprotein IIb/IIIa receptor blocker. The results were compared with the outcome of routine stenting in recent randomized trials. RESULTS: Angioplasty was performed in 1058 patients of whom 369 (34.9%) received a stent. The angiographic success rate was 98.9%. During hospital stay, 4.8% of the patients suffered any cardiac event. At one-year follow-up, death occurred in 1.1%, MI in 3.3%, TLR in 12.4% and any event in 16.7% of the patients. Event-free survival at one-year was 82.3%. These results compare favorably with routine stenting in recent trials. CONCLUSIONS: Aggressive balloon angioplasty with provisional stenting yields excellent results in a general patient population.

  8. Safety and efficacy of recombinant Hirudin (CGP 39 393) versus Heparin in patients with stable angina undergoing coronary angioplasty

    NARCIS (Netherlands)

    A.A. van den Bos (Arjan); G.R. Heyndrickx (Guy); G-J. Laarman (GertJan); H. Suryapranata (Harry); F. Zijlstra (Felix); P. Close (Philip); J.J.M.M. Rijnierse (Joep); H.R. Büller (Harry); P.W.J.C. Serruys (Patrick); J.W. Deckers (Jaap)

    1993-01-01

    textabstractBACKGROUND. Enhanced thrombin activity has been associated with acute and long-term complications following balloon angioplasty (percutaneous transluminal coronary angioplasty (PTCA). We evaluated, in a 2-to-1 randomized, double-blind trial, the effects of recombinant hirudin, CGP 39 393

  9. Pumpkin Balloon

    OpenAIRE

    Nishimura, Jun; 西村, 純

    1992-01-01

    The Pumpkin shaped balloons, which are the extreme case of the heart-type balloons had been studied as one of the promising candidate of the super pressure balloons. Here, detailed studies for the features of the pumpkin balloons are described, particularly by comparing with those of the spherical shaped super pressure balloons.

  10. THE KISSING BALLOON TECHNIQUE WITH 2 OVER-THE-WIRE BALLOON CATHETERS THROUGH A SINGLE 8-FRENCH GUIDING CATHETER

    NARCIS (Netherlands)

    DENHEIJER, P; BERNINK, PJLM; VANDIJK, RB; TWISK, SPM; LIE, KI

    1991-01-01

    Some of the newer over-the-wire coronary angioplasty catheters have shaft sizes of 3.0 French (F) or less. The inner diameter of modern 8-F guiding catheters is large enough to accommodate two of such balloon catheters. We report a kissing balloon procedure with two over-the-wire catheters through a

  11. THE KISSING BALLOON TECHNIQUE WITH 2 OVER-THE-WIRE BALLOON CATHETERS THROUGH A SINGLE 8-FRENCH GUIDING CATHETER

    NARCIS (Netherlands)

    DENHEIJER, P; BERNINK, PJLM; VANDIJK, RB; TWISK, SPM; LIE, KI

    Some of the newer over-the-wire coronary angioplasty catheters have shaft sizes of 3.0 French (F) or less. The inner diameter of modern 8-F guiding catheters is large enough to accommodate two of such balloon catheters. We report a kissing balloon procedure with two over-the-wire catheters through a

  12. Ammonia Synthesis at Low Pressure.

    Science.gov (United States)

    Cussler, Edward; McCormick, Alon; Reese, Michael; Malmali, Mahdi

    2017-08-23

    Ammonia can be synthesized at low pressure by the use of an ammonia selective absorbent. The process can be driven with wind energy, available locally in areas requiring ammonia for synthetic fertilizer. Such wind energy is often called "stranded," because it is only available far from population centers where it can be directly used. In the proposed low pressure process, nitrogen is made from air using pressure swing absorption, and hydrogen is produced by electrolysis of water. While these gases can react at approximately 400 °C in the presence of a promoted conventional catalyst, the conversion is often limited by the reverse reaction, which makes this reaction only feasible at high pressures. This limitation can be removed by absorption on an ammine-like calcium or magnesium chloride. Such alkaline metal halides can effectively remove ammonia, thus suppressing the equilibrium constraints of the reaction. In the proposed absorption-enhanced ammonia synthesis process, the rate of reaction may then be controlled not by the chemical kinetics nor the absorption rates, but by the rate of the recycle of unreacted gases. The results compare favorably with ammonia made from a conventional small scale Haber-Bosch process.

  13. [Role of angioplasty in the treatment of renal artery stenosis].

    Science.gov (United States)

    Armero, S; Bonello, L; Paganelli, F; Barragan, P; Roquebert, P-O; Commeau, P

    2011-12-01

    Atherosclerotic renal artery stenosis is frequent and is associated with a high incidence of morbidity and mortality, with a strong correlation with coronary artery disease, (Kalra et al., 2005; Cheung et al., 2002; Guo et al., 2007 [1-3]). The atherosclerotic renal artery stenosis is an independent predictive factor of death (Conlon et al., 1998 [4]). The treatment of this lesion does not have strong evidence. A lot of studies in this area suggest the angioplasty is superior in a big majority between surgery, and angioplasty with stent is superior between balloon angioplasty, but some studies fail to prove the superiority of angioplasty versus medical treatment. These studies have sadly a lot of mistakes and nowadays we don't know what is the treatment for our patients in a lot of cases. The angioplasty is indicated when there is a failure of antihypertensive medications for control of blood pressure, when it is associated with a renal insufficiency quickly progressive or when there is a lesion on each renal artery. Other studies must be organized for prove the superiority of angioplasty when there is a real stenosis, maybe with the use of fractional flow reserve.

  14. Angioplasty and Vascular Stenting

    Science.gov (United States)

    ... flow in the graft or fistula making it inadequate for dialysis, angioplasty is generally the first line ... inform your doctor about recent illnesses or other medical conditions. Women ... does the equipment look like? In these procedures, x-ray imaging ...

  15. 可注射珊瑚人工骨与经皮球囊成型修复股骨头坏死%Percutaneous balloon angioplasty combined with injectable coral artificial bone repairs femoral head necrosis

    Institute of Scientific and Technical Information of China (English)

    朱康华; 孟志斌; 黄涛; 谭海涛; 孙博; 庞学毅

    2016-01-01

    BACKGROUND: There are many methods for the treatment of femoral head necrosis, such as core decompression, bone graft, arthroplasty and joint replacement, and each of which has its own shortcomings. So, percutaneous bal oon angioplasty combined with coral artificial bone provides a new attempt for the treatment of femoral head necrosis. OBJECTIVE: To observe the effect of percutaneous bal oon angioplasty combined with coral artificial bone on femoral head necrosis repair. METHODS: Twenty-four Duroc piglets were enrol ed to establish bilateral femoral head necrosis models by liquid nitrogen freezing method. Then, model piglets were randomly treated with percutaneous bal oon angioplasty combined with injectable coral artificial bone (experimental group) or bone cement (control group) on one affected side, and meanwhile, given no treatment on the contralateral side (blank control group). At 2, 4, 8 and 16 weeks after surgery, X-ray examination, biomechanical test and histological detection were conducted. RESULTS AND CONCLUSION: X-ray showed that at 16 weeks after surgery, numerous new bones could be found in the experimental group and there was a fuzzy boundary between the artificial bone and surrounding tissues; no new bone formed in the control group, and the boundary was clear; in the blank control group, the surface of the femoral head col apsed, and bone trabeculae arranged disorderly, which were seriously destroyed. And in the histological detection at 16 weeks after surgery, there were numerous bone trabecula and osteoblasts around the coral bone in the experimental group, and the coral artificial bone almost dissolved; in the control group, bone cement was in an irregular shape and no bone trabecula formed; in the blank control group, bone trabecula were damaged in the col apsed area, whose structure was in disorder. Additional y, biomechanical changes in the experimental group were significantly better than those in the other two groups at different time

  16. Balloon angioplasty to disrupt fibrin sheaths in tunneled dialysis catheters for the treatment of catheter dysfunctionb%球囊破坏纤维鞘纠正血液透析导管功能不良效果观察

    Institute of Scientific and Technical Information of China (English)

    詹申; 杨涛; 张丽红; 刘丽芳; 王玉柱

    2014-01-01

    目的 探索一种处理纤维鞘的新方法以改善透析患者的血流量.方法 6例无法建立动静脉内瘘并有多次多部位中心静脉导管留置史的维持性血液透析患者,经血管造影(Digital Substraction Angiography (DSA)证实存在导管相关纤维鞘.对纤维鞘行经皮腔内球囊扩张血管成形术(percutaneous transluminal angioplasty,PTA),然后经颈内静脉或股静脉途径置入长期中心静脉导管.结果术后应用导管透析,1例患者第2次透析时血流量为220ml/min,其余患者血流量均在250ml/min以上,随访2~6个月,所有患者均未出现导管功能不良及感染.结论球囊破坏纤维鞘可以改善导管的通畅性及血流量.

  17. Percutaneous balloon angioplasty of coarctation of the aorta in children: 12-year follow-up results%经皮球囊血管成形术治疗先天性主动脉缩窄:12年随访结果

    Institute of Scientific and Technical Information of China (English)

    李奋; 周爱卿; 高伟; 王荣发; 余志庆; 黄美蓉; 杨建萍

    2001-01-01

    目的总结我院27例次经皮球囊血管成形术治疗先天性主动脉缩窄12年随访结果,以评价该介人方法的长期疗效及影响疗效的因素。方法 1987年9月至1999年8月,共有24例先天性主动脉缩窄患儿接受了27次经皮球囊血管成形术治疗,其中19例为局限性峡部缩窄(隔膜型),4例为主动脉弓发育不良型,1例为手术后再狭窄。选择的球囊直径一般不超过缩窄段近端主动脉直径(11.06±2.80mm与11.78±3.18mm),球囊/缩窄段之比为2~4(平均2.57±0.68)。术后随访6月~12年,平均6.2±2.8年。跨缩窄段压差≤20 mm Hg为疗效良好。结果术后跨缩窄段压差由48.17±14.68 mm Hg下降至14.96±13.12 mm Hg(P<0.01),缩窄段直径由4.66±2.43 mm增加至8.80±3.32 mm(P<0.01)。19例(79%)患儿即刻疗效良好。5例疗效不良患儿中,4例为发育不良型,1例为隔膜型。19例疗效良好患儿中,18例为隔膜型,1例为手术后再狭窄。1例隔膜型初次疗效良好的患儿随访中压差上升至30 mm Hg,2年半后接受第二次扩张术并获良好疗效;1例发育不良型患儿即刻疗效不佳,7年后再次行扩张术但疗效仍不理想;1例隔膜型但初次疗效不佳的患儿7年后再次行扩张术获良好效果。随访中无动脉瘤及其它并发症发生。结论经皮球囊血管成形术可有效治疗手术后复发性或隔膜型主动脉缩窄,对发育不良型治疗效果不佳。%Objective To evaluate the efficiency of percutaneous balloon angioplasty of coarctation ot the aorta in children and discuss its risk factors that can lead to poor long-term results. Mehods From September 1987 to August 1999, 24 patients underwent 27 balloon angioplasty procedures for native or recurrent coarctation of the aorta at our institution. There were 19 patients with discrete (membranous) coarctation, 4 patients with long-segment and aortic arch hypoplasia, and 1 patient with postoperative

  18. Femoral artery recanalisation with percutaneous angioplasty and segmentally enclosed plasminogen activator

    DEFF Research Database (Denmark)

    Jørgensen, B; Tønnesen, K H; Bülow, J;

    1989-01-01

    To establish whether re-occlusion of the femoral artery could be prevented, in 6 consecutive patients undergoing percutaneous transluminal angioplasty (PTA) for superficial femoral artery occlusion the recanalised segment was isolated, with a 7-French double-balloon catheter. 5 mg recombined human...

  19. Quantitative angiographic assessment of elastic recoil after percutaneous transluminal coronary angioplasty

    NARCIS (Netherlands)

    B.J.W.M. Rensing (Benno); W.R.M. Hermans (Walter); K.J. Beatt (Kevin); G-J. Laarman (GertJan); H. Suryapranata (Harry); M.J.B.M. van den Brand (Marcel); P.J. de Feyter (Pim); P.W.J.C. Serruys (Patrick)

    1990-01-01

    textabstractLittle is known about the elastic behavior of the coronary vessel wall directly after percutaneous transluminal coronary angioplasty (PTCA). Minimal luminal cross-sectional areas of 151 successfully dilated lesions were studied in 136 patients during balloon inflation and directly after

  20. Quantitative angiographic assessment of elastic recoil after percutaneous transluminal coronary angioplasty

    NARCIS (Netherlands)

    B.J.W.M. Rensing (Benno); W.R.M. Hermans (Walter); K.J. Beatt (Kevin); G-J. Laarman (GertJan); H. Suryapranata (Harry); M.J.B.M. van den Brand (Marcel); P.J. de Feyter (Pim); P.W.J.C. Serruys (Patrick)

    1990-01-01

    markdownabstractAbstract Little is known about the elastic behavior of the coronary vessel wall directly after percutaneous transluminal coronary angioplasty (PTCA). Minimal luminal cross-sectional areas of 151 successfully dilated lesions were studied in 136 patients during balloon inflation and

  1. Angioplasty simulation using ChainMail method

    Science.gov (United States)

    Le Fol, Tanguy; Acosta-Tamayo, Oscar; Lucas, Antoine; Haigron, Pascal

    2007-03-01

    Tackling transluminal angioplasty planning, the aim of our work is to bring, in a patient specific way, solutions to clinical problems. This work focuses on realization of simple simulation scenarios taking into account macroscopic behaviors of stenosis. It means simulating geometrical and physical data from the inflation of a balloon while integrating data from tissues analysis and parameters from virtual tool-tissues interactions. In this context, three main behaviors has been identified: soft tissues crush completely under the effect of the balloon, calcified plaques, do not admit any deformation but could move in deformable structures, the blood vessel wall undergoes consequences from compression phenomenon and tries to find its original form. We investigated the use of Chain-Mail which is based on elements linked with the others thanks to geometric constraints. Compared with time consuming methods or low realism ones, Chain-Mail methods provide a good compromise between physical and geometrical approaches. In this study, constraints are defined from pixel density from angio-CT images. The 2D method, proposed in this paper, first initializes the balloon in the blood vessel lumen. Then the balloon inflates and the moving propagation, gives an approximate reaction of tissues. Finally, a minimal energy level is calculated to locally adjust element positions, throughout elastic relaxation stage. Preliminary experimental results obtained on 2D computed tomography (CT) images (100x100 pixels) show that the method is fast enough to handle a great number of linked-element. The simulation is able to verify real-time and realistic interactions, particularly for hard and soft plaques.

  2. Laser angioplasty of totally occluded arteries of the limb

    Science.gov (United States)

    Szopinski, Piotr; Hara, Marek; Noszczyk, Wojciech

    1996-03-01

    The authors summarize their experience in the use of Nd-YAG laser in chronic occlusion of lower limb arteries. Percutaneous transluminal laser angioplasty (PTLA) with laser-heated metal and sapphire tips were used as an adjuvant to conventional balloon angioplasty. In cases of reocclusions, endovascular stents were implanted. Laser recanalization was performed in 46 arteries (iliac, superficial femoral, and popliteal). Indications for the procedure were: limb salvage, claudication below 100 m, and temporal or rest pain. Initial clinical and hemodynamic improvement was observed in 37 (80%) patients. Four perforations occurred without clinical sequel. The one-year cumulative clinical patency was 27 (58%) of the 46 lesions. PTLA may be appropriate for high-risk patients, who are unsuitable for surgical reconstruction because of the concomitant diseases. The combination of laser recanalization and implantation of vascular stents may be a promising method in the management of limb ischemia.

  3. 脉冲电场介导AT2R基因在血管局部表达及其对血管新生内膜的影响%Electroporation-mediated angiotensin Ⅱ type 2 receptor expression improves neo intimal hyperplasia of carotid arteries in rats after balloon angioplasty

    Institute of Scientific and Technical Information of China (English)

    刘德峰; 屈小玲; 刘建平

    2011-01-01

    Objective To determine the effects of electroporation on the transfection of angiotensin Ⅱ type 2 receptor (AT2R) gene into rat carotid arteries and predict its role in neointimal hyperplasia of carotid arteries after balloon angioplasty. Methods After the establishment of rat carotid balloon injury restenosis model, 18 SD rats were divided into AT2R transfection group, empty plasmid transfection group (GFP), and non-transfection group (n = 6 ). AT2R gene plasmid or empty plasmid was transfected by electroporation into rat carotid arteries. Their arteries were harvested at 3, 14 and 21 d after gene transfer, with 2 rats at each time points. The expression of AT2B and morphology of the arteries were evaluated by immunohistochemistry and HE staining respoctively. Results Electroporation-mediated transfection of AT2R gene into injured rat carotid arteries significantly up-regulated the levels of AT2R mRNA in the neointima in a time dependent manner from day 3 to day 14 ( strong to moderate to mild expression). But no expression of AT2B was found in the other 2 groups at these 3 time points. At day 21, AT2R transfection significantly reduced intimal/medial area ratio as compared with non-transfection group and GFP transfection group (0.76 ± 0.08 vs 1.39 ± 0.08 and 1.32 ± 0. 10, P < 0.01 ). No significant difference was found between non-transfection group and GFP transfection group. Conclusion Our results indicate that electroporation is an effective means to introduce naked AT2R DNA into the blood vessel wall, and gene transfer of AT2R in vessel wall may effectively inhibit VSMC proliferation and neointimal hyperplasia in the rat carotid arteries after balloon angioplasty.%目的 研究脉冲电场对血管紧张素2型受体(AT2R)基因在血管局部表达的作用,探讨AT2R基因在体转染对大鼠颈动脉球囊损伤后新生内膜增生的作用.方法 大鼠颈动脉球囊损伤后,用脉冲电穿孔法介导AT2R cDNA真核表达质粒或空质粒载

  4. Use of Reactor-Produced Radioisotopes for Prevention Restenosis After Angioplasty

    Energy Technology Data Exchange (ETDEWEB)

    Knapp, F.F.; Pipes, D.W.

    1999-12-21

    Coronary heart disease leads to myocardial infarction and is a major cause of death in the US. Myocardial infarctions result from atherosclerotic plaque deposits in the coronary arteries, reducing blood flow through these arteries which supply oxygen and nutrients to the heart muscle. The two major approaches for restoring adequate blood flow are coronary bypass graft surgery and coronary angioplasty. Angioplasty is a routinely used clinical procedure, where a deflated balloon attached to the end of a long catheter is inserted into an artery in the leg and then advanced through the aorta into the blocked regions of the coronary arteries. After positioning in the occluded region of the artery, the balloon is inflated with a pressurized saline solution which opens the artery restoring blood flow by pressing the atherosclerotic plaque into the vessel wall. Angioplasty is a widely performed procedure with the coronary arteries and is a much less expensive alternative to coronary bypass surgery. The best patients for angioplasty are those with single occlusions and this method is preferred over bypass grafting because of the significantly reduced expense. The reformation of plaque deposits in arteries (restenosis) following angioplasty, however, is a major clinical problem encountered in as high as 40 percent of patients. Because reduction of health care costs is a major national priority, development of effective new preventative methods for restenoses is an important national priority.

  5. Low pressure microfluidic-based DNA fragmentation

    NARCIS (Netherlands)

    Shui, Lingling; Sparreboom, Wouter; Bomer, Johan G.; Jin, Mingliang; Carlen, Edwin; van den Berg, Albert

    2011-01-01

    We report a low-pressure microfluidic deoxyribonucleic acid (DNA) fragmentation device based on a combination of me-chanical hydrodynamic shearing and low temperature sample heating. Conventional DNA fragmentation based on hydrody-namic shearing is capable of achieving fragment lengths (FL) < 10k bp

  6. Percutaneous angioplasty of portal vein stenosis that complicated liver transplantation: the mid-term therapeutic results

    Energy Technology Data Exchange (ETDEWEB)

    Park, Kwang Bo; Choo, Sung Wook; Do, Young Soo; Shin, Sung Wook; Cho, Sung Gi; Choo, In Wook [Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul (Korea, Republic of)

    2005-09-15

    We wanted to valuate the mid-term therapeutic results of percutaneous transhepatic balloon angioplasty for portal vein stenosis after liver transplantation. From May 1996 to Feb 2005, 420 patients underwent liver transplantation. Percutaneous transhepatic angioplasty of the portal vein was attempted in six patients. The patients presented with the clinical signs and symptoms of portal venous hypertension or they were identified by surveillance doppler ultrasonography. The preangioplasty and postangioplasty pressure gradients were recorded. The therapeutic results were monitored by the follow up of the clinical symptoms, the laboratory values, CT and ultrasonography. The overall technical success rate was 100%. The clinical success rate was 83% (5/6). A total of eight sessions of balloon angioplasty were performed in six patients. The mean pressure gradient decreased from 14.5 mmHg to 2.8 mmHg before and after treatment, respectively. The follow up periods ranged from three months to 64 months (mean period; 32 months). Portal venous patency was maintained in all six patients until the final follow up. Combined hepatic venous stenosis was seen in one patient who was treated with stent placement. One patient showed puncture tract bleeding, and this patient was treated with coil embolization of the right portal puncture tract via the left transhepatic portal venous approach. Percutaneous transhepatic balloon angioplasty is an effective treatment for the portal vein stenosis that occurs after liver transplantation, and our results showed good mid-term patency with using this technique.

  7. Low Pressure Nuclear Thermal Rocket (LPNTR) concept

    Science.gov (United States)

    Ramsthaler, J. H.

    1991-01-01

    A background and a description of the low pressure nuclear thermal system are presented. Performance, mission analysis, development, critical issues, and some conclusions are discussed. The following subject areas are covered: LPNTR's inherent advantages in critical NTR requirement; reactor trade studies; reference LPNTR; internal configuration and flow of preliminary LPNTR; particle bed fuel assembly; preliminary LPNTR neutronic study results; multiple LPNTR engine concept; tank and engine configuration for mission analysis; LPNTR reliability potential; LPNTR development program; and LPNTR program costs.

  8. Low-Pressure-Drop Shutoff Valve

    Science.gov (United States)

    Thornborrow, John

    1994-01-01

    Flapper valve remains open under normal flow conditions but closes upon sudden increases to high rate of flow and remains closed until reset. Valve is fluid/mechanical analog of electrical fuse or circuit breaker. Low-pressure-drop shutoff valve contains flapper machined from cylindrical surface. During normal flow conditions, flapper presents small cross section to flow. (Useful in stopping loss of fluid through leaks in cooling systems.)

  9. Properties of nylon 12 balloons after thermal and liquid carbon dioxide treatments.

    Science.gov (United States)

    Ro, Andrew J; Davé, Vipul

    2013-03-01

    Critical design attributes of angioplasty balloons include the following: tear resistance, high burst pressures, controlled compliance, and high fatigue. Balloons must have tear resistance and high burst pressures because a calcified stenosis can be hard and nominal pressures of up to 16 atm can be used to expand the balloon. The inflated balloon diameter must be a function of the inflation pressure, thus compliance is predictable and controlled. Reliable compliance is necessary to prevent damage to vessel walls, which may be caused by over-inflation. Balloons are often inflated multiple times in a clinical setting and they must be highly resistant to fatigue. These design attributes are dependent on the mechanical properties and polymer morphology of the balloon. The effects of residual stresses on shrinkage, crystallite orientation, balloon compliance, and mechanical properties were studied for angioplasty nylon 12 balloons. Residual stresses of these balloons were relieved by oven heat treatment and liquid CO2 exposure. Residual stresses were measured by quantifying shrinkage at 80 °C of excised balloon samples using a dynamic mechanical analyzer. Shrinkage was lower after oven heat treatment and liquid CO2 exposure compared to the as-received balloons, in the axial and radial directions. As-received, oven heat treated, and liquid CO2-exposed balloon samples exhibited similar thermal properties (T(g), T(m), X(t)). Crystallite orientation was not observed in the balloon cylindrical body using X-ray scattering and polarized light microscopy, which may be due to balloon fabrication conditions. Significant differences were not observed between the stress-strain curves, balloon compliance, and average burst pressures of the as-received, oven heat treated, and liquid CO2-exposed balloons.

  10. Percutaneous transluminal coronary angioplasty. A review of the literature

    Energy Technology Data Exchange (ETDEWEB)

    Przybojewski, J.Z.; Weich, H.F.H. (Tygerberg Hospital, Stellenbosch (South Africa). Dept. of Internal Medicine)

    1984-01-25

    The purpose of this article is to review PTCA, percutaneous transluminal coronary angioplasty, which can be considered to be a truly revolutionary and fairly simple invasive form of intervention to atherosclerotic obstruction. The 'epidemic' of IHD, ischaemic heart disease, in the Republic of South Africa calls for the employment of this technique, which has already been carried out in a few teaching hospitals in this country. Very recently, modified balloon dilatation catheters have been used percutaneously in the non-operative transluminal correction of congenital coarctation of the aorta in infants and children, congenital pulmonary value stenosis, and hypoplasia and stenosis of the pulmonary arteries. It has also been employed for PTCA and for the simultaneous occlusion of coronary-bronchial artery anastomosis using a detachable balloon. The isotopes thallium 201 and technetium 99 were also used in scintiscanning.

  11. Prediction of outcome after femoropopliteal balloon angioplasty by intravascular ultrasound

    DEFF Research Database (Denmark)

    Vogt, K C; Just, S; Rasmussen, John Bøje Grønvall

    1997-01-01

    arteries remained patent. Two occlusions and two stenoses developed during the first 3 months after the intervention and one occlusion occurred after 1 year. The following IVUS parameters were related to a favourable patency: presence of calcification; dissection or plaque rupture and residual stenosis...

  12. Cutting balloons for the treatment of vascular stenoses

    Energy Technology Data Exchange (ETDEWEB)

    Tsetis, Dimitrios [University Hospital of Heraklion, Department of Radiology, Medical School of Crete, Heraklion (Greece); Morgan, Robert; Belli, Anna-Maria [St George' s Hospital, Department of Radiology, London (United Kingdom)

    2006-08-15

    The aim of this article is to review the mechanism, technical characteristics, biological response and clinical applications of cutting balloon angioplasty in peripheral vessels. The cutting balloon is a non-compliant, balloon catheter equipped with three-to-four microtome-sharp atherotomes. When used appropriately, it is safe and easy to use, with a high immediate success rate and few complications, provided oversizing is avoided. There is some evidence that pre-dilation with a standard or high-pressure balloon may also predispose to vascular rupture. The cutting balloon has proved to be beneficial in treating difficult complex lesions in the coronary arteries. Early experience in non-coronary vessels shows that cutting balloon angioplasty can be used to treat peripheral bypass anastomotic and haemodialysis fistula stenoses that are resistant to conventional high-inflation pressures. Its application in de novo peripheral arterial lesions and non-coronary in-stent restenosis is still under discussion. Theoretically, this device induces a smaller degree of vessel wall injury localised to the area of incisions and sparing the interincisional segments; however, this postulated reduction in restenosis rates has not been confirmed in clinical practice. (orig.)

  13. Percutaneous laser thermal angioplasty: initial clinical results with a laser probe in total peripheral artery occlusions.

    Science.gov (United States)

    Cumberland, D C; Sanborn, T A; Tayler, D I; Moore, D J; Welsh, C L; Greenfield, A J; Guben, J K; Ryan, T J

    1986-06-28

    A metal-tipped laser fibre was used during percutaneous angioplasty of femoral/popliteal or iliac artery occlusions in 56 patients. Primary success was achieved in 50 (89%) of these total occlusions, providing a channel for subsequent balloon dilatation. Before the procedure, 18 lesions had been judged untreatable by conventional angioplasty and four of the six failures were in these. Complications directly attributable to the laser probe were one case of vessel perforation and two cases of entry into vessel walls; these had no sequelae. Other acute complications were a distal thrombosis in a non-heparinised patient, requiring local streptokinase treatment, and two reocclusions and one transient peripheral embolic episode in the first 24 hours. The laser probe technique has potential for increasing the proportion of patients suitable for angioplasty.

  14. Influences on vascular wall smooth muscle cells with novel short-duration thermal angioplasty

    Science.gov (United States)

    Kunio, M.; Shimazaki, N.; Arai, T.; Sakurada, M.

    2012-02-01

    We investigated the influences on smooth muscle cells after our novel short-duration thermal angioplasty, Photo-thermo Dynamic Balloon Angioplasty (PTDBA), to reveal the mechanism that can suppress neo-intimal hyperplasia after PTDBA. We obtained the sufficient arterial dilatations by short-duration heating (angioplasty in vivo. The measured neo-intimal hyperplasia occupancy rate was less than 20% after PTDBA in vivo. We prospect that the inhibition of the growth factor's expression by stretch-fixing may result to suppress the neo-intimal hyperplasia. In addition, the decrease of smooth muscle cells' density in the vessel media by heating might be another reason for the neo-intimal hyperplasia suppression.

  15. Successful Venous Angioplasty of Superior Vena Cava Syndrome after Heart Transplantation

    Directory of Open Access Journals (Sweden)

    Thomas Strecker

    2014-01-01

    Full Text Available Introduction. For patients with terminal heart failure, heart transplantation (HTX has become an established therapy. Before transplantation there are many repeated measurements with a pulmonary artery catheter (PAC via the superior vena cava (SVC necessary. After transplantation, endomyocardial biopsy (EMB is recommended for routine surveillance of heart transplant rejection again through the SVC. Case Presentation. In this report, we present a HTX patient who developed a SVC syndrome as a possible complication of all these procedures via the SVC. This 35-year-old Caucasian male could be successfully treated by balloon dilatation/angioplasty. Conclusion. The SVC syndrome can lead to pressure increase in the venous system such as edema in the head and the upper part of the body and further serious complications like cerebral bleeding and ischemia, or respiratory problems. Balloon angioplasty and stent implantation are valid methods to treat stenoses of the SVC successfully.

  16. The clinical application of percutaneous transluminal balloon angioplasty for hemodialysis patients with stenosis of arteriovenous ifstula%经皮腔内血管成形术在血透患者动静脉内瘘血管狭窄中的应用

    Institute of Scientific and Technical Information of China (English)

    郑尘非; 孙文学; 贾秀芬; 缪克凯; 潘慧君; 刘毅; 黄朝兴

    2015-01-01

    Objective: To report the technical success and long-term clinical outcomes of arteriovenous ifstula (AVF) stenosis after percutaneous transluminal balloon angioplasty (PTA).Methods: A total of 30 patients with stenosis of AVF were enrolled. There were 16 men and 14 women, and the median age was 64.8±13.2 years. Mean time between ifstula creation and intervention was 16.5±13.8 months. The mean duration of hemodialysis time was 31.5±30.2 months. They were examined by digital subtraction angiography (DSA) when they under-went PTA. After the treatment of PTA, all of the patients were examined by 64-multislice spiral computed tomog-raphy angiography every 3 months.Results: The technical success rate was 90.0% in the hemodialysis patients (17 native AVFs and 10 arteriovenous grafts). Primary patency at ifrst, second, third, fourth and iffth three months was 100%, 91.3%, 79.5%, 72.6% and 62.2% respectively. Univariate analysis indicated that there was no signiif-cant correlation between the clinical factors (including age, diabetes mellitus, location, length, grade, and number of stenosis) and primary patency (P>0.05).Conclusion: PTA is an effective treatment method for arteriovenous stenosis, which has high rates of technical success and less complication.%目的:探讨经皮腔内血管成形术(PTA)治疗动静脉内瘘(AVF)狭窄的疗效。方法:回顾性分析30例上肢AVF狭窄患者的临床资料,其中男16例,女14例,平均年龄(64.8±13.2)岁;瘘管平均使用时间(16.5±13.8)月,患者平均透析时间(31.5±30.2)月。所有患者在数字减影血管造影(DSA)下行PTA,术后每3个月经64层螺旋CT血管造影对AVF功能进行评估。结果:本组手术成功率90.0%,其中17例自体AVF和10例人工血管动静脉内瘘(AVG)。术后27例患者首次开通率3个月为100%,6个月为91.3%,9个月为79.5%,12个月为72.6%,15个月为62.2%;术后AVF首次通畅率的单因素Cox风

  17. Low-pressure pulmonary artery aneurysm presenting with pulmonary embolism: a case series

    Directory of Open Access Journals (Sweden)

    Papoulidis Pavlos

    2011-04-01

    Full Text Available Abstract Introduction Pulmonary artery aneurysm is an uncommon disorder with severe complications. The diagnosis is often difficult, since the clinical manifestations are non-specific and the treatment is controversial, as the natural history of the disease is not completely understood. Case presentation We describe the cases of two patients with pulmonary artery aneurysms. The first patient was a 68-year-old Caucasian man with an idiopathic low-pressure pulmonary artery aneurysm together with a pulmonary embolism. The patient preferred a conservative approach and was stable at the 10-month follow-up visit after being placed on anti-coagulant treatment. The second patient was a 66-year-old Caucasian woman with a low-pressure pulmonary artery aneurysm also presented together with a pulmonary embolism. The aneurysm was secondary to pulmonary valve stenosis. She received anti-coagulants and, after stabilization, underwent percutaneous balloon valvuloplasty. Conclusion Pulmonary embolism may be the initial presentation of a low-pressure pulmonary artery aneurysm. No underlying cause for pulmonary embolism was found in either of our patients, suggesting a causal association with low-pressure pulmonary artery aneurysm.

  18. Intravascular optical coherence tomography to characterize tissue deformation during angioplasty: preliminary experiments with artery phantoms

    Science.gov (United States)

    Azarnoush, Hamed; Vergnole, Sébastien; Pazos, Valérie; Bisaillon, Charles-Étienne; Boulet, Benoit; Lamouche, Guy

    2012-09-01

    We explored the potential of intravascular optical coherence tomography (IVOCT) to assess deformation during angioplasty balloon inflation. Using a semi-compliant balloon and artery phantoms, we considered two experimental scenarios. The goal for the first scenario was to investigate if variation in the elasticity of the structure surrounding the balloon could be sensed by IVOCT monitoring. In this scenario, we used three single-layer phantoms with various mechanical properties. Image analysis was performed to extract the inner and outer diameters of the phantoms at various pressures. The goal for the second scenario was twofold. First, we investigated the IVOCT capability to monitor a more complex balloon inflation process. The balloon was in a folded state prior to inflation. This allowed studying two stages of deformation: during balloon unfolding and during balloon expansion. Second, we investigated IVOCT capability to monitor the deformation in a three-layer phantom used to better mimic a true artery. So, not only were the IVOCT images processed to provide the inner and outer diameters of the phantom, but the layer thicknesses were also determined. In both scenarios, IVOCT monitoring revealed to be very efficient in providing relevant information about the phantom deformation during balloon inflation.

  19. [The practical clinical guidelines of the Sociedad Española de Cardiología on interventional cardiology: coronary angioplasty and other technics].

    Science.gov (United States)

    Esplugas, E; Alfonso, F; Alonso, J J; Asín, E; Elizaga, J; Iñiguez, A; Revuelta, J M

    2000-02-01

    Interventional cardiology has had an extraordinary expansion in last years. This clinical guideline is a review of the scientific evidence of the techniques in relation to clinical and anatomic findings. The review includes: 1. Coronary arteriography. 2. Coronary balloon angioplasty. 3. Coronary stents. 4. Other techniques: directional atherectomy, rotational atherectomy, transluminal extraction atherectomy, cutting balloon, laser angioplasty and transmyocardial laser and endovascular radiotherapy. 5. Platelet glycoprotein IIb/IIIa inhibitors. 6. New diagnostic techniques: intravascular ultrasound, coronary angioscopy, Doppler and pressure wire. For the recommendations we have used the classification system: class I, IIa, IIb, III like in the guidelines of the American College of Cardiology and the American Heart Association.

  20. Primary angioplasty for infarction due to isolated right ventricular artery occlusion

    Institute of Scientific and Technical Information of China (English)

    Anwar; A; Chahal; Min-Young; Kim; Alexander; N; Borg; Yahya; Al-Najjar

    2014-01-01

    We report an unusual case of an isolated right ventricular infarction with haemodynamic compromise caused by spontaneous isolated proximal occlusion of the right ventricular branch of the right coronary artery(RCA), successfully treated by balloon angioplasty. A 58-yearold gentleman presented with epigastric pain radiating into both arms. Electrocardiograph with right ventricular leads confirmed ST elevation in V4 R and a diagnosis of isolated right ventricular infarction was made. Urgent primary percutaneous intervention was performed which revealed occlusion of the right ventricular branch of the RCA. During the procedure, the patient’s blood pressure dropped to 80/40 mm Hg, and echocardiography showed impaired right ventricular systolic function. Despite aggressive fluid resuscitation, the patient remained hypotensive, continued to have chest pain and persistent electrocardiograph changes, and hence balloon angioplasty was performed on the proximal right ventricular branch which restored flow to the vessel and revealed a severe ostial stenosis. This was treated with further balloon angioplasty which restored TIMI 3 flow with resolution of patient’s symptoms. Repeat echocardiography showed complete resolution of theST-elevation in leads V4 R and V5 R and partial resolution in V1. Subsequent dobutamine-stress echocardiography at 4 wk showed good left and right ventricular contractions. The patient was discharged after a 3-d inpatient stay without any complications.

  1. Investigations into low pressure methanol synthesis

    DEFF Research Database (Denmark)

    Sharafutdinov, Irek

    The central topic of this work has been synthesis, characterization and optimization of novel Ni-Ga based catalysts for hydrogenation of CO2 to methanol. The overall goal was to search for materials that could be used as a low temperature (and low pressure) methanol synthesis catalyst....... Among them, Ni-Ga has been chosen, primarily due to low price of constituent metals. After the preliminary optimization work, an optimal catalyst composition and preparation method has been suggested. Indeed, for an optimal catalyst, which is a SiO2 supported Ni-Ga prepared from a solution of nitrates...... due to carbon formation) and under accelerated ageing conditions (due to dealloying). However, the initial activity could always be restored after treatment in hydrogen flow at elevated temperatures. The work in the direction of suppression of deactivation and by-product formation is still in progress....

  2. Paclitaxel-coated balloons - Survey of preclinical data.

    Science.gov (United States)

    Schnorr, B; Kelsch, B; Cremers, B; Clever, Y P; Speck, U; Scheller, B

    2010-10-01

    Restenosis following interventions in the coronary or peripheral arteries develops over weeks to months. In coronary arteries the restenosis rate has been markedly reduced since the advent of drug-eluting stents. Non-stent-based methods for local drug delivery enable restenosis inhibition without the need for stent implantation, does not permanently change the structure of the vessel, are repeatable, and seems to be applicable where drug-eluting stents provide insufficient protection. Preclinical data indicate that short exposure of the vessel wall to a lipophilic inhibitor of cell proliferation is sufficient for preventing restenosis. Initial evidence to this effect emerged from an investigation of paclitaxel embedded in a matrix that enhances the solubility and release of the agent from the balloon coating as well as its transfer to the vessel wall. Further corroborating data from preclinical and clinical studies demonstrating a reduction in late lumen loss and lower restenosis rates led to the market introduction of a variety of paclitaxel-coated angioplasty balloons. The effectiveness of restenosis inhibition is not determined by the active agent alone. Other factors that are crucial for the effectiveness and safety of drug-coated angioplasty balloons are the formulation containing the agent and the coating technique. In this review we first outline the development of paclitaxel-coated balloons to then provide an overview of the preclinical results obtained with different paclitaxel-coated balloons and finally compare these with the outcome in patients. The article concludes with a short outlook on initial results with a zotarolimus-coated angioplasty balloon.

  3. Drug-eluting balloon catheters for lower limb peripheral arterial disease: the evidence to date

    Directory of Open Access Journals (Sweden)

    Barkat M

    2016-05-01

    Full Text Available Mohamed Barkat,1 Francesco Torella,1 George A Antoniou2 1Liverpool Vascular and Endovascular Service, Royal Liverpool University Hospital, Liverpool, 2Department of Vascular and Endovascular Surgery, The Royal Oldham Hospital, Pennine Acute Hospitals NHS Trust, Manchester, UK Abstract: A significant proportion of patients with severe lower limb peripheral arterial disease require revascularization. Over the past decade, an endovascular-first approach even for complex disease has gained widespread use among vascular specialists. An important limitation of percutaneous transluminal balloon angioplasty or stenting remains the occurrence of restenosis. Drug-coated balloons have emerged as an exciting technology developed to overcome the limitations of standard balloon angioplasty and stenting. Drug-eluting devices inhibit neointimal growth of vascular smooth muscle cells with the potential of preventing restenosis. This review provides a synopsis of the up-to-date evidence on the role of drug-coated balloons in the treatment of lower limb peripheral arterial disease. Bibliographic searches were conducted using MEDLINE, EMBASE, and the Cochrane Library electronic database. Eleven randomized clinical trials, two systematic reviews, and a published registry providing the best available evidence were identified. Current evidence suggests that angioplasty with drug-coated balloon is reliable, safe, and efficient in increasing patency rates and reducing target lesion revascularization and restenosis. However, it remains unknown whether these improved results can translate into beneficial clinical outcomes, as current randomized clinical trials have failed to demonstrate a significant benefit in limb salvage and mortality. Further randomized trials focusing on clinical and functional outcomes of drug-eluting balloons and on cost versus clinical benefit are required. Keywords: drug-eluting balloon, drug-coated balloon, angioplasty, peripheral arterial

  4. Emerging Stent and Balloon Technologies in the Femoropopliteal Arteries

    Directory of Open Access Journals (Sweden)

    Georgios Pastromas

    2014-01-01

    Full Text Available Endovascular procedures for the management of the superficial femoral (SFA and popliteal artery disease are increasingly common. Over the past decade, several stent technologies have been established which may offer new options for improved clinical outcomes. This paper reviews the current evidence for SFA and popliteal artery angioplasty and stenting, with a focus on randomized trials and registries of nitinol self-expanding stents, drug-eluting stents, dug-coated balloons, and covered stent-grafts. We also highlight the limitations of the currently available data and the future routes in peripheral arterial disease (PAD stent and balloon technology.

  5. Drug-eluting balloon catheters for lower limb peripheral arterial disease: the evidence to date

    Science.gov (United States)

    Barkat, Mohamed; Torella, Francesco; Antoniou, George A

    2016-01-01

    A significant proportion of patients with severe lower limb peripheral arterial disease require revascularization. Over the past decade, an endovascular-first approach even for complex disease has gained widespread use among vascular specialists. An important limitation of percutaneous transluminal balloon angioplasty or stenting remains the occurrence of restenosis. Drug-coated balloons have emerged as an exciting technology developed to overcome the limitations of standard balloon angioplasty and stenting. Drug-eluting devices inhibit neointimal growth of vascular smooth muscle cells with the potential of preventing restenosis. This review provides a synopsis of the up-to-date evidence on the role of drug-coated balloons in the treatment of lower limb peripheral arterial disease. Bibliographic searches were conducted using MEDLINE, EMBASE, and the Cochrane Library electronic database. Eleven randomized clinical trials, two systematic reviews, and a published registry providing the best available evidence were identified. Current evidence suggests that angioplasty with drug-coated balloon is reliable, safe, and efficient in increasing patency rates and reducing target lesion revascularization and restenosis. However, it remains unknown whether these improved results can translate into beneficial clinical outcomes, as current randomized clinical trials have failed to demonstrate a significant benefit in limb salvage and mortality. Further randomized trials focusing on clinical and functional outcomes of drug-eluting balloons and on cost versus clinical benefit are required. PMID:27274265

  6. Mechanical behavior of PDMS at low pressure

    Science.gov (United States)

    Bunyan, J.; Tawfick, S.

    2017-07-01

    Polydimethylsiloxanes (PDMS) are used in a wide range of soft devices including lab-on-chip, soft robots and flexible electronics. These technologies are currently considered for space exploration applications. We experimentally study the effects of vacuum pressure on the dynamics of PDMS resonator and demonstrate that, unlike hard materials, it exhibits an appreciable change in modulus manifested as a shift in resonance frequency with varying pressure. To reveal this dependence, we carefully probe the dissipation due to air pressure damping acting on the surface of the membrane. For a 1 µm thick membrane, the modulus of the PDMS decreases when the pressure is below P t  =  3.175 Torr, whereas at pressures above {{P}\\text{t}} the dynamics are dominated by gas damping in the free molecular flow and viscous regimes. We conjecture that the observed effect is a consequence of a change in shear modulus resulting in a logarithmic linear relationship between pressure and stiffness for a circular PDMS membrane. These results are important for the application of PDMS microdevices at low pressure.

  7. Peripheral Applications of Drug-Coated Balloons: Past, Present and Future

    Energy Technology Data Exchange (ETDEWEB)

    Krokidis, Miltiadis, E-mail: mkrokidis@hotmail.com; Spiliopoulos, Stavros, E-mail: stavspiliop@upatras.gr; Katsanos, Konstantinos, E-mail: katsanos@med.upatras.gr; Sabharwal, Tarun, E-mail: tarun_sabharwal@yahoo.co.uk [Guy' s and St. Thomas' Hospitals, NHS Foundation Trust, Department of Radiology (United Kingdom)

    2013-04-15

    Drug-coated balloon (DCB) technologies represent the latest and hottest development in the field of endovascular treatment of peripheral arterial disease. Initial experience with paclitaxel-coated balloon use in the femoral artery has demonstrated lower mid-term restenosis and superior mid-term clinical outcomes in terms of improved wound healing and reduced repeat angioplasty rates compared with standard balloon angioplasty. Many companies are presently developing and/or improving DCB catheters and therefore ongoing, technical improvements of the already existing platforms, new drugs, and innovative carriers are expected. The ongoing basic research studies and various multicenter randomized, controlled trials that are currently in progress will offer valuable scientific insights regarding the long-term effectiveness and other crucial issues, such as efficacy in various vascular beds, optimal balloon dosage, and post angioplasty antiplatelet therapy. Future applications of these devices also could include in-stent restenosis, anastomotic stenosis of surgical bypass, and benign stenoses of the central venous system. The authors envision that DCB angioplasty will evolve to a major paradigm shift in the endovascular treatment of occlusive vascular diseases.

  8. Development of a novel catheter preventing the outflow of debris and thrombus on percutaneous transluminal angioplasty for hemodialysis access fistulas.

    Science.gov (United States)

    Horita, Yuki; Namura, Masanobu; Matsumura, Masami

    2006-06-01

    If a large amount of debris or thrombus dislodges from a lesion because of dilation of the stenotic or occluded lesion in the hemodialysis access fistula when angioplasty is performed, it may move into the pulmonary artery via the central vein, resulting in pulmonary embolism. A novel sheath has been developed to prevent the outflow of debris or thrombus to the central vein. The catheter consists of a 5 F sheath introducer and a silicone balloon attached at the tip of the sheath. The silicon balloon is inflated via small inflation lumen on the shaft wall of the sheath. In the case of percutaneous transluminal angioplasty (PTA), the silicone balloon is inflated to block the blood flow by a mixture of contrast medium and physiological saline, and then dilate a stenotic or occluded lesion by PTA balloon. Next, the debris and thrombus are aspirated using the flush-lumen of this device. Finally, the silicone balloon is deflated and the dilation of the lesion is confirmed. A case of hemodialysis access fistula graft with massive thrombotic occlusion was presented. This device enabled Fogarty procedure using PTA balloon and the blood flow of the graft was completely improved and a large amount of thrombus was removed. This novel device is useful to prevent the embolic complication of the intervention for hemodialysis access fistula. Copyright 2006 Wiley-Liss., Inc.

  9. Venous rupture complicating hemodialysis access angioplasty: percutaneous treatments and outcomes

    Energy Technology Data Exchange (ETDEWEB)

    La, Young Jong; Goo, Dong Erk; Kim, Dae Ho; Lee, Hae Kyoung; Hong, Hyun Suk; Kwon, Gui Hyang; Choi, Duk Lin; Ynag, Sung Boo [College of Medicine, Soonchunhyang Univ., Seoul (Korea, Republic of)

    2002-03-01

    To evaluate the usefulness of percutaneous management and prognosis in venous rupture during angioplasty of hemodialytic arteriovenous fistulas. Among 814 patients who underwent angioplasty on account of inadequate hemodialysis, 63(39 women and 24 men aged 20-78 (mean, 55.8) years) were included in this study. All 63 had peripheral venous stenosis. Venous rupture was diagnosed when contrast leakage was seen at venography after percutaneous angioplasty (PTA). In order to manage venous rupture, the sites at which this occurred were compressed manually for 3-5 minutes or blood flow was blocked with a balloon catheter for the same period. In one case, a stent was inserted at the rupture site. Using the Kaplan-Meier method, we investigated the patency rate of arteriovenous fistula (AVF) in cases of successful PTA. We also compared PTA patency rates in cases with and without peripheral venous rupture. Venous rupture occurred in 38 cephalic, 16 brachial, and 9 basilic veins. In 63 patients, bleeding stopped and in 54 (85.7 %) of thee, PTA was successful. Among the nine failed cases, dilatation was incomplete in five, though bleeding had stopped. In patients with brachial and cephalic vein rupture the venous tract at the rupture site was not located. Two patients underwent surgery: one of these experienced brachial venous rupture, with incontrollable bleeding, and the other had nerve compression symptoms due to hematoma. Among 54 patients in whom PTA was successful, the primary and secondary six-months rates for angioaccess were 47.9% and 81.2%, and the mean patency period was 6.1 and 15.8 months, respectively. In cases of non-venous rupture, the mean patency period was 9.6 months, significantly longer than in cases involving venous rupture (p=0.02). Venous rupture occurring during the PTA of hemodialytic AVF can be managed percutaneously.

  10. Restenosis of the coronary stenotic lesions treated by holmium:YAG laser coronary angioplasty

    Science.gov (United States)

    Miyazaki, Shunichi; Nonogi, Hiroshi; Goto, Yoichi; Itoh, Akira; Ozono, Keizaburo; Daikoku, Satoshi; Haze, Kazuo

    1994-07-01

    Clinical efficacy of newly developed Holmium YAG laser coronary angioplasty (HLCA) was assessed for 30 patients with angina. There were 12 near left main trunk (LMT) lesions and 4 aorto- ostial lesions. Adjunctive balloon angioplasty was performed for 25 of 30 lesions. Delivered energy ranged from 1.5 to 2.5 watts/pulse and the total exposure time ranged from 6 to 55 seconds. External diameter of laser catheter was 1.5 mm for 13 lesions, 1.4 mm for 17 lesions, and 1.7 mm for 5 lesions. Laser success, defined as 20% reduction of stenotic ratio, was obtained in 21 of 30 (70%) and overall procedural success rate was 93%. There were 3 cases with acute coronary occlusions relieved by adjunctive balloon angioplasty and one coronary perforation without manifestation of cardiac tamponade. There were no large coronary dissection which involved more than 5 mm of the coronary artery. Follow up coronary angiography after 3 months showed restenosis in 14 of 27 patients (52%). Percent stenosis after lasering (56%) was similar to that at 3 months after (62%). HLCA is acutely effective treatment for lesions near LMT, because of low incidence of large coronary dissection. However, angiographical restenosis rate is high at 3 months after HLCA. This may be attributed to the relatively large residual stenosis after the procedure and vessel injury caused by shock wave.

  11. Intravascular ultrasound-guided angioplasty of hemodialysis loop graft in a patient with contrast allergy.

    Science.gov (United States)

    Casey, Patrick E; Miranda, Charles J; Al-Khaffaf, Haytham; Woodhead, Peter M

    2014-01-01

    A surveillance duplex scan detected a stenosis within a left groin hemodialysis loop graft in a 57-year-old woman who was allergic to both iohexol and gadolinium contrast agents. This precluded the use of standard angioplasty treatment techniques. Intravascular ultrasound (IVUS) uses a catheter mounted with a miniaturized ultrasound probe to produce detailed cross-sectional vessel images. Clinically, it has been used in the assessment of coronary artery disease but has also supplemented standard angiography techniques in the assessment of peripheral vascular and hemodialysis access lesions. IVUS was utilized as the solitary imaging modality to identify the graft stenosis and guide the placement of a 6 mm diameter angioplasty balloon. Two areas of stenosis were successfully dilated and subsequent IVUS re-examination showed abolition of the stenosis. Twelve-month follow-up surveillance scan showed that the graft remained functional with good flow rates. In the setting of contrast allergy, IVUS may provide a valid and safe tool in the localization and treatment of peripheral vessel stenosis, including arteriovenous fistula angioplasty. To our knowledge this is the first reported use of IVUS for hemodialysis graft salvage adopting a completely 'contrast-free' technique. More studies are required to establish the true role of IVUS in the management of hemodialysis access angioplasty, but this successful case contributes valuable information to the literature on its clinical application.

  12. Heme oxygenase-1 alleviates cigarette smoke-induced restenosis after vascular angioplasty by attenuating inflammation in rat model.

    Science.gov (United States)

    Ni, Leng; Wang, Zhanqi; Yang, Genhuan; Li, Tianjia; Liu, Xinnong; Liu, Changwei

    2016-03-14

    Cigarette smoke is not only a profound independent risk factor of atherosclerosis, but also aggravates restenosis after vascular angioplasty. Heme oxygenase-1 (HO-1) is an endogenous antioxidant and cytoprotective enzyme. In this study, we investigated whether HO-1 upregulating by hemin, a potent HO-1 inducer, can protect against cigarette smoke-induced restenosis in rat's carotid arteries after balloon injury. Results showed that cigarette smoke exposure aggravated stenosis of the lumen, promoted infiltration of inflammatory cells, and induced expression of inflammatory cytokines and adhesion molecules after balloon-induced carotid artery injury. HO-1 upregulating by hemin treatment reduced these effects of cigarette smoke, whereas the beneficial effects were abolished in the presence of Zincprotoporphyrin IX, an HO-1 inhibitor. To conclude, hemin has potential therapeutic applications in the restenosis prevention after the smokers' vascular angioplasty. Copyright © 2016. Published by Elsevier Ireland Ltd.

  13. Drug-coated balloons are replacing the need for nitinol stents in the superficial femoral artery.

    Science.gov (United States)

    Kitrou, Panagiotis; Karnabatidis, Dimitrios; Katsanos, Konstantinos

    2016-08-01

    Amassed evidence from several randomized controlled trials and high quality meta-analyses clearly support the primary use of paclitaxel-coated balloons (PCB) in the superficial femoral artery over traditional plain balloon angioplasty or primary bare nitinol stenting with significantly lower vascular restenosis, less need for repeat procedures, improved quality of life and potential cost savings for the healthcare system. Stents may be reserved for bail-out in case of a suboptimal dilatation result, and for selected more complex lesions, or in case of critical limb ischemia in order to eliminate vessel recoil and maximize immediate hemodynamic gain. Debulking atherectomy remains unproven, but holds a lot of promise in particular in combination with PCBs, in order to improve compliance of the vessel wall by plaque removal, allow for a better angioplasty result and optimize drug transfer and bioavailability. The present overview summarizes and discusses current evidence about femoropopliteal PCB angioplasty compared to the historical standard of plain old balloon angioplasty and bare nitinol stents. Available evidence is appraised in the context of clinically meaningful results, relevant unresolved issues are highlighted, and future trends are discussed.

  14. Which angiographic variable best describes functional status 6 months after successful single-vessel coronary balloon angiopasty?

    NARCIS (Netherlands)

    B.J.W.M. Rensing (Benno); W.R.M. Hermans (Walter); P.J. de Feyter (Pim); P.W.J.C. Serruys (Patrick); J.W. Deckers (Jaap)

    1993-01-01

    textabstractOBJECTIVES. The aim of this study was to determine which quantitative angiographic variable best describes functional status 6 months after coronary balloon angioplasty. BACKGROUND. Several angiographic restenosis criteria have been developed. These can be divided into those that describ

  15. Peripheral pulsed laser angioplasty - 4-year clinical experience; Periphere gepulste Laserangioplastie - Erfahrungen nach 4jaehrigem klinischen Einsatz

    Energy Technology Data Exchange (ETDEWEB)

    Huppert, P.E. [Tuebingen Univ. (Germany). Abt. fuer Radiologische Diagnostik; Duda, S.H. [Tuebingen Univ. (Germany). Abt. fuer Radiologische Diagnostik; Kalighi, K. [Tuebingen Univ. (Germany). Abt. fuer Thorax-, Herz- und Gefaesschirurgie; Baumbach, A. [Tuebingen Univ. (Germany). Abt. 3, Medizinische Klinik; Seboldt, H. [Tuebingen Univ. (Germany). Abt. fuer Thorax-, Herz- und Gefaesschirurgie; Claussen, C.D. [Tuebingen Univ. (Germany). Abt. fuer Radiologische Diagnostik

    1994-02-01

    In 134 patients, 21 iliac, 91 femoropopliteal and 22 crural arterial occlusions were treated by percutaneous laser-assisteed angioplasty and in 32 patients femoropopliteal occlusions by conventional balloon angioplasty. Laser angioplasty could be performed in 126 patients following initial guide wire recanalisation using 9, 7 and 4.5-F multifibre catheters, respectively. In 72 patients a 308-nm excimer laser and in 54 patients a 504-nm pulsed day laser was used. Luminal opening by laser angioplasty was obtained in 102 of 126 (81%) procedures (9 incomplete catheter passages, 15 persistent occlusions). 95% of iliac, 90% of femoropopliteal and 77% of crural recanalisations including supplemental balloon dilatations (n=105) and stent implantations (n-24) succeeded technically. Clinical success rates at 1 (2) years after angioplasty weere 95% (89%) for iliac, 66% (63%) for femoropopliteal and 57% (50%) for crural treatments. Technical and clinical results of laser-assissted femoropopliteal recanalisations showed no significant differences in comparison to the results of conventional balloon angioplasty. The use of pulsed lasers for the treatment of peripheral arterial occlusive disease would require further technical improvements. (orig.) [Deutsch] Bei 134 Patienten mit arterieller Verschlusskrankheit wurden 21 iliakale, 91 femoropopliteale und 22 krurale Okklusionen einer Behandlung durch perkutane laserassistierte Angioplastie zugefuehrt und bei 32 Patienten femoropoliteale Okklusionen vergleichsweise einer konventionellen Ballonangioplastie. 126 Laserangioplastien konnten mit 9, 7 und 4,5-F-Multifaserkathetern nach initialer Fuehrungsdrahtpassage durchgefuehrt werden. Bei 72 Eingriffen wurde ein 308-nm-Excimerlaser und bei 54 ein 405-nm-Farbstofflaser verwendet. Eine Lumeneroeffnung gelang bei 102 von 126 (81%) Laserangioplastien (9 inkomplette Katheterpassagen, 15 persistierende Okklusionen). 95% iliakaler, 90% femoropoplitealer und 77% kruraler laserassistierter

  16. Low pressure cooling seal system for a gas turbine engine

    Science.gov (United States)

    Marra, John J

    2014-04-01

    A low pressure cooling system for a turbine engine for directing cooling fluids at low pressure, such as at ambient pressure, through at least one cooling fluid supply channel and into a cooling fluid mixing chamber positioned immediately downstream from a row of turbine blades extending radially outward from a rotor assembly to prevent ingestion of hot gases into internal aspects of the rotor assembly. The low pressure cooling system may also include at least one bleed channel that may extend through the rotor assembly and exhaust cooling fluids into the cooling fluid mixing chamber to seal a gap between rotational turbine blades and a downstream, stationary turbine component. Use of ambient pressure cooling fluids by the low pressure cooling system results in tremendous efficiencies by eliminating the need for pressurized cooling fluids for sealing this gap.

  17. A novel fluoroscopic-assisted balloon thrombectomy technique for thrombosed hemodialysis prosthetic grafts [corrected].

    Science.gov (United States)

    Kakkos, Stavros K; Haddad, Joseph A; Haddad, Georges K

    2010-01-01

    Previous studies have shown that stenosis of the arterial anastomosis of thrombosed hemodialysis (HD) grafts, unmasked after conventional thrombectomy, very often necessitate subsequent arterial angioplasty. The aim of this study was to describe a novel fluoroscopic-assisted balloon thrombectomy technique which permits simultaneous arterial angioplasty (should this is required) for thrombosed HD grafts. Thirty patients with 36 thrombotic episodes of their prosthetic HD grafts participated in this study. A balloon angioplasty catheter is placed beyond the arterial anastomosis, over a guidewire; the balloon is inflated with contrast solution under fluoroscopy and pulled back to remove the arterial thrombus from the anastomosis. Any coexisting stenosis revealed by balloon indentation is completely dilated at that time, rather than after the thrombectomy. Mechanical thrombolysis of the graft and venous outflow is then performed with the AngioJet catheter (Possis Medical, Inc). Technical and clinical success rates (the latter defined as one subsequent HD session) of the procedure were 100% and 94%, respectively. No complications, including arterial embolism, vessel rupture or pulmonary embolism, were encountered. Primary assisted patency at 3 and 6 months was 51% and 32%, respectively, while functional secondary patency at the same follow-up points was 78%. Our technique is safe and also effective in both short- and long-term follow-up. Because it offers convenience, since the treatment of arterial anastomotic stenoses is accomplished in one (rather than two) steps, this method deserves further investigation.

  18. Emergency coronary angioplasty in refractory unstable angina

    NARCIS (Netherlands)

    P.J. de Feyter (Pim); P.W.J.C. Serruys (Patrick); M.J.B.M. van den Brand (Marcel); K. Balakumaran (Kulasekaram); A.L. Soward; P.G. Hugenholtz (Paul); A.E.R. Arnold (Alfred); B. Mochtar (Bas)

    1985-01-01

    textabstractWe performed percutaneous transluminal coronary angioplasty as an emergency procedure in 60 patients with unstable angina pectoris that was refractory to treatment with maximally tolerated doses of beta-blockers, calcium antagonists, and intravenous nitroglycerin. The initial success

  19. Below-the-ankle Angioplasty and Stenting for Limb Salvage: Anatomical Considerations and Long-term Outcomes

    Energy Technology Data Exchange (ETDEWEB)

    Katsanos, Konstantinos, E-mail: katsanos@med.upatras.gr; Diamantopoulos, Athanasios; Spiliopoulos, Stavros; Karnabatidis, Dimitris; Siablis, Dimitris [School of Medicine, Patras University Hospital, Department of Interventional Radiology (Greece)

    2013-08-01

    PurposeTo report the long-term angiographic and clinical results in a series of below-the-ankle (BTA) angioplasty procedures and to present some biomechanical issues related to the unique anatomical geometry of the ankle.MethodsWe performed a retrospective analysis of BTA angioplasty procedures. Clinical end points included technical success, patient mortality, salvage of the treated foot, and repeat target lesion revascularization. Imaging end points included primary patency, binary restenosis of the target lesion at the 50 % threshold, and stent integrity (stent fracture, deformation, or collapse). Univariate subgroup analysis was performed.ResultsIn total, 40 limbs in 37 patients (age 73.5 {+-} 8.2 years) with critical limb ischemia were included and 42 inframalleolar lesions (4.2 {+-} 1.4 cm) were analyzed. Technical success was achieved in 95.2 % (40 of 42). Provisional stent placement was performed in 45.2 % (19 of 42). Two patients died, and two major amputations occurred up to 3 years. At 1 year, overall primary vessel patency was 50.4 {+-} 9.1 %, lesion binary restenosis rate was 64.1 {+-} 8.3 %, and repeat intervention-free survival was 93.6 {+-} 4.3 % according to life table analysis of all treated lesions. Pairwise subgroup analysis showed that BTA self-expanding stents were associated with significantly higher restenosis and poorer primary patency compared to plain balloon angioplasty or sirolimus-eluting balloon-expandable stents. Significant deformation and/or fracture of balloon-expandable stents placed BTA were identified in five of 11. Dynamic imaging showed that the dorsalis pedis artery is kinked during foot dorsiflexion, whereas the distal posterior tibial artery is kinked during plantar flexion of the foot.ConclusionBTA angioplasty for critical limb ischemia treatment is safe and feasible with satisfactory long-term results. BTA stent placement must be reserved for bailout indications.

  20. Restenosis following balloon dilation of benign esophageal stenosis

    Institute of Scientific and Technical Information of China (English)

    Ying-Sheng Cheng; Ming-Hua Li; Ren-Jie Yang; Hui-Zhen Zhang; Zai-Xian Ding; Qi-Xin Zhuang; Zhi-Ming Jiang; Ke-Zhong Shang

    2003-01-01

    AIM: To elucidate the mechanism of restenosis following balloon dilation of benign esophageal stenosis.METHODS: A total of 49 rats with esophageal stenosis were induced in 70 rats using 5 ml of 50 % sodium hydroxide solution and the double-balloon method, and an esophageal restenosis (RS) model was developed by esophageal stenosis using dilation of a percutaneous transluminal coronary angioplasty (PTCA) balloon catheter. These 49 rats were divided into two groups: rats with benign esophageal stricture caused by chemical burn only (control group, n=21) and rats with their esophageal stricture treated with balloon catheter dilation (experimental group, n=28). Imaging analysis and immunohistochemistry were used for both quantitative and qualitative analyses of esophageal stenosis and RS formation in the rats, respectively.RESULTS: Cross-sectional areas and perimeters of the esophageal mucosa layer, muscle layer, and the entire esophageal layers increased significantly in the experimental group compared with the control group. Proliferating cell nuclear antigen (PCNA) was expressed on the 5th day after dilation, and was still present at 1 month. Fibronectin (FN)was expressed on the 1st day after dilation, and was still present at 1 month.CONCLUSION: Expression of PCNA and FN plays an important role in RS after balloon dilation of benign esophageal stenosis.

  1. Bulk characterization of pharmaceutical powders by low-pressure compression

    DEFF Research Database (Denmark)

    Sørensen, A.H.; Sonnergaard, Jørn; Hovgaard, L.

    2005-01-01

    for characterization purposes. Significant correlation was demonstrated between several of the compression and tapping-derived parameters. The discriminative power of the low-pressure compression test was discussed using the compressed density at 0.2 MPa, correlated with the tapped density, and the relative Walker...... coefficient, correlated with the Compressibility Index, as examples. The compressed density at 0.2 MPa and the relative Walker coefficient demonstrated excellent discriminative power, superior to the discriminative power of the correlated tapping derived parameters. The low-pressure compression test......Low-pressure compression of pharmaceutical powders using small amounts of sample (50 mg) was evaluated as an alternative to traditional bulk powder characterization by tapping volumetry. Material parameters were extrapolated directly from the compression data and by fitting with the Walker...

  2. Scientific ballooning in Brazil

    Science.gov (United States)

    Corrêa, R.; Rinke, E.; Fernandes, J. O.; Villela, T.

    We present an overview of the scientific ballooning activities that took place in Brazil over the past 30 years as well as the current ongoing efforts in the area. We also briefly describe the balloon launching facility that exists at the Instituto Nacional de Pesquisas Espaciais (National Institute for Space Research) — INPE. Up to now, over 100 scientific balloon experiments, related to Astrophysics, Aeronomy, and Geophysics were launched from Brazil taking advantage of the country's continental dimensions, a well-defined rain season, and a low population density, which offer excellent conditions for scientific ballooning activities. Balloons with volumes up to 500,000 cubic meters can be launched from INPE's balloon launching base (latitude S 22° 4' 2″; longitude W 044° 58' 41″). The availability of good roads and several inland airports in Brazil provides the necessary structure for safe payload retrieval and its rapid return to the balloon base. There are several airports throughout Brazil that can also be used as balloon launching bases, mainly in the country's Eastern region. Overflights of more than 1,000 kilometers are possible and easily attained. Balloon flights ranging from a few hours to long duration flights can be safely verified. The constant climate monitoring through the use of weather satellites information received at INPE provides the necessary data to determine the necessary conditions for a long duration flight. INPE's Center for Weather Forecast and Climate Studies (CPTEC) provides the necessary weather forecast support for launch and payload retrieval.

  3. GHOST balloons around Antarctica

    Science.gov (United States)

    Stearns, Charles R.

    1988-01-01

    The GHOST balloon position as a function of time data shows that the atmospheric circulation around the Antarctic Continent at the 100 mb and 200 mb levels is complex. The GHOST balloons supposedly follow the horizontal trajectory of the air at the balloon level. The position of GHOST balloon 98Q for a three month period in 1968 is shown. The balloon moved to within 2 deg of the South Pole on 1 October 1968 and then by 9 December 1968 was 35 deg from the South Pole and close to its position on 1 September 1968. The balloon generally moved from west to east but on two occasions moved in the opposite direction for a few days. The latitude of GHOST balloons 98Q and 149Z which was at 200 mb is given. Both balloons tended to get closer to the South Pole in September and October. Other GHOST balloons at the same pressure and time period may not indicate similar behavior.

  4. Initial clinical experience with a new pulsed dye laser device in angioplasty of limb ischemia and shunt fistula obstructions

    Energy Technology Data Exchange (ETDEWEB)

    Zwaan, M.; Weiss, H.D.; Kagel, H.; Gmelin, E.; Rinast, E. (Medical University of Luebeck (Germany). Department of Radiology); Goethlin, J.H. (Sahlgrenska Sjukhuset, Goeteborg (Sweden)); Kummer, D. (Medical University of Luebeck (Germany). Department of Angiology and Geriatry); Scheu, M. (Medical Laser Center Luebeck (Germany))

    Selective plaque ablation with laser radiation at 405-530 nm in vitro has been reported. The possibilities are investigated of a new pulsed dye laser device for in vivo recanalization of arteries in ischemic lower limbs and stenoses/occlusions of arterio-venous hemo-dialysis shunt fistulae. A specially designed 9F or 7F multifiber catheter was used for treatment of 10 patients with lower limb artery obliterations and 11 patients with malfunctioning hemodialysis access fistulae (HAF). The recanalization technical success was 5/5 in the iliac arteries (IA), 4/5 in the superficial femoral arteries (SFA), and 11/11 in the HAF. Early re-occlusions occurred in one SFA and IA, respectively, caused by very bad run-off. There was one clinically insignificant SFA perforation. Additional balloon angioplasty was considered necessary in 10/16 lesions. Mean ankle-arm index increased from 0.68 to 0.97. With two exceptions all HAF patients were re-integrated in the dialysis program. Pulsed dye laser angioplasty promises to be an effective and fast method for plaque ablation debulking. The first clinical experience confirms previous in vitro results. In particular laser recanalization may become the method of choice for treatment of rigid HAF obstructions and it seems to be superior to vascular surgery or balloon angioplasty alone. (author). 15 refs.; 2 figs.

  5. Effect of percutaneous transluminal angioplasty on the stenosis of autogenous radiocephalic ateriovenous fistula for hemodialysis

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Sun Min; Kim, Jeong Ho; Byun, Sung Su; Kang, Jin MMo; Choi, Sang Tae; Kim, Jong Woo; Kim, Hyung Sik; Choi, Hye Young [Gachon University Gil Medical Center, Incheon (Korea, Republic of); Park, Jae Hyung [Dept. of Radiology, Seonam University College of Medicine, Myongji Hospital, Goyang (Korea, Republic of)

    2016-02-15

    The purpose of this study was to evaluate the effectiveness of percutaneous transluminal angioplasty (PTA) on stenosis of autogenous radiocephalic arteriovenous fistula (RCF) for hemodialysis and to determine the factors influencing patency. This retrospective study included 136 patients referred for PTA of RCF stenosis between March 2005 and July 2014. The technical success rate, complications, and patency rate were evaluated. The following factors were analyzed as they might influence patency: age, gender, site and duration of arteriovenous fistula, underlying disease, body mass index, hypercholesterolemia, smoking, peripheral artery or coronary artery occlusive disease, stenosis length/grade, cutting balloon, and balloon size. The initial technical success rate was 91.9% (125/136). Complications included vessel rupture (n = 2) and vessel dissection (n = 2). The patency rates at 6, 12, 24, and 48 months after PTA were 81.9, 67.1, 52.7, and 42.3%, respectively. The patency rate was higher in cases with longer (> 3 cm) stenosis (p = 0.04). Use of cutting balloon and larger size of balloon catheter made the patency longer, but this difference was not statistically significant (p = 0.637, 0.258). PTA is a safe and effective way to manage stenosis in RCF. The length of stenosis was the only factor which affected the patency rate in this study.

  6. A low pressure filter system for new containment concepts

    Energy Technology Data Exchange (ETDEWEB)

    Dillmann, H.G.; Pasler, H. [Kernforschungszentrum Karlsruhe GmbH Laboratorium fuer Isotopentechnik, Karlsruhe (Germany)

    1995-02-01

    It is demonstrated that after severe accidents the decay heat can be removed in a passive mode in a convective flow, i.e. without needing a fan. The filter components with sufficiently low pressure drop values which are required for this purpose will be described and the results indicated.

  7. Spontaneous low-pressure headache complicating bag-piping.

    Science.gov (United States)

    Patrick, Alasdair; McAuley, David; Roxburgh, Richard

    2007-04-01

    We describe an interesting case of a 40-year-old lady who developed a spontaneous low-pressure headache whilst playing the bag-pipes. Playing wind instruments requires the generation of significant intra-thoracic pressure, which may have contributed to this musician's condition.

  8. LOW PRESSURE ULTRAVIOLET STUDIES FOR INACTIVATION OF GIARDIA MURIS CYSTS

    Science.gov (United States)

    Cysts of Giardia muris were inactivated using a low pressure ultravolet (UV) light source. Cyst viability was detemined by both in vitro excystation and animal infectivity. Cyst doeses were counted using a flow cytometer for the animal infectivity experiments. Using in vitro excy...

  9. LOW PRESSURE ULTRAVEIOLET STUDIES FOR INACTIVATION OF GIARDIA MURIS CYSTS

    Science.gov (United States)

    Cysts of Giardia muris were inactivated using a low pressure ultravolet (UV) light source. Cyst viability was detemined by both in vitro excystation and animal infectivity. Cyst doeses were counted using a flow cytometer for the animal infectivity experiments. Using in vitro excy...

  10. Low-pressure valves in hydrocephalic children : a retrospective analysis

    NARCIS (Netherlands)

    Breimer, G. E.; Sival, Deborah; Hoving, E. W.

    2012-01-01

    A series of 100 children under 2 years of age treated for hydrocephalus is described. All patients received a standard differential low-pressure (SD low) valve as the first cerebrospinal fluid (CSF) shunt treatment. The performance of this group during follow-up is analysed. A retrospective cohort s

  11. Low-pressure valves in hydrocephalic children : a retrospective analysis

    NARCIS (Netherlands)

    Breimer, G. E.; Sival, Deborah; Hoving, E. W.

    2012-01-01

    A series of 100 children under 2 years of age treated for hydrocephalus is described. All patients received a standard differential low-pressure (SD low) valve as the first cerebrospinal fluid (CSF) shunt treatment. The performance of this group during follow-up is analysed. A retrospective cohort s

  12. The Application of Dual-wire Balloon in The Treatment of Coronary Bifurcation Lesions

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Objectives To assess the efficiency and safety of dual-wire balloon angioplasty side branch combined stenting the main branch in the treatment of coronary bifurcation lesions. Methods This study included thirty-six patients with 41 coronary bifurcation lesions. Selective dual-wire balloon angioplasty was performed in side branch and/or in main branch, and implantation of stents was performed in main branch only. Clinical outcome and major adverse cardiac events were observed inhospital and follow-up. Results Success rate of side branch dilatation before main branch stenting was 100%; main branch direct stenting performed in 4 cases; success main branch dilatation performed in the other 37 cases; kissing technique was performed successfully in 5 cases, which side branch was jailed after main branch stenting with TIMI grade 0-2 flow. No Q-wave myocardial infarction, acute revascularization and death occurred during in-hospital.Clinical follow-up was available in all patients. No Q-wave myocardial infarction, revascularization and death occurred, angina pectoris recurred in three patients,released by strengthen drug treatment. Conclusions Dual-wire balloon angioplasty side branch combined stenting the main branch is simple, safe and effective for the treatment of coronary bifurcation lesions.

  13. Fibrin sheath angioplasty: a technique to prevent superior vena cava stenosis secondary to dialysis catheters.

    Science.gov (United States)

    Hacker, Robert I; Garcia, Lorena De Marco; Chawla, Ankur; Panetta, Thomas F

    2012-09-01

    Fibrin sheaths are a heterogeneous matrix of cells and debris that form around catheters and are a known cause of central venous stenosis and catheter failure. A total of 50 cases of central venous catheter fibrin sheath angioplasty (FSA) after catheter removal or exchange are presented. A retrospective review of an outpatient office database identified 70 eligible patients over a 19-month period. After informed consent was obtained, the dialysis catheter exiting the skin was clamped, amputated, and a wire was inserted. The catheter was then removed and a 9-French sheath was inserted into the superior vena cava, a venogram was performed. If a fibrin sheath was present, angioplasty was performed using an 8 × 4 or 10 × 4 balloon along the entire length of the fibrin sheath. A completion venogram was performed to document obliteration of the sheath. During the study, 50 patients were diagnosed with a fibrin sheath, and 43 had no pre-existing central venous stenosis. After FSA, 39 of the 43 patient's (91%) central systems remained patent without the need for subsequent interventions; 3 patients (7%) developed subclavian stenoses requiring repeat angioplasty and stenting; 1 patent (2.3%) developed an occlusion requiring a reintervention. Seven patients with prior central stenosis required multiple angioplasties; five required stenting of their central lesions. Every patient had follow-up fistulograms to document long-term patency. We propose that FSA is a prudent and safe procedure that may help reduce the risk of central venous stenosis from fibrin sheaths due to central venous catheters.

  14. Clefting in pumpkin balloons

    Science.gov (United States)

    Baginski, F.; Schur, W.

    NASA's effort to develop a large payload, high altitude, long duration balloon, the Ultra Long Duration Balloon, focuses on a pumpkin shape super-pressure design. It has been observed that a pumpkin balloon may be unable to pressurize into the desired cyclically symmetric equilibrium configuration, settling into a distorted, undesired stable state instead. Hoop stress considerations in the pumpkin design leads to choosing the lowest possible bulge radius, while robust deployment is favored by a large bulge radius. Some qualitative understanding of design aspects on undesired equilibria in pumpkin balloons has been obtained via small-scale balloon testing. Poorly deploying balloons have clefts, but most gores away from the cleft deploy uniformly. In this paper, we present models for pumpkin balloons with clefts. Long term success of the pumpkin balloon for NASA requires a thorough understanding of the phenomenon of multiple stable equilibria and means for quantitative assessment of measures that prevent their occurrence. This paper attempts to determine numerical thresholds of design parameters that distinguish between properly deploying designs and improperly deploying designs by analytically investigating designs in the vicinity of criticality. Design elements which may trigger the onset undesired equilibria and remedial measures that ensure deployment are discussed.

  15. The usefulness of wire-loop technique for percutaneous angioplasty of insufficient hemodialysis fistula

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Dong Hun; Goo, Dong Erk; Kim, Dae Ho; Choi, Deuk Lin; Moon, Chul [College of Medicine, Soonchunhyang University, Seoul (Korea, Republic of)

    2000-10-01

    To evaluate the usefulness of the wire-loop technique, used to perform percutaneous transluminal angioplasty (PTA) in occluded arteriovenous fistula when standard methods fail to pass the balloon catheter across the stenotic segment. In 30 patients (M:F = 14:16; aged 27-77 (mean, 51.3) years), the Wire-Loop technique was used to perform percutaneous transluminal angioplasty of insufficiently hemodialysed arteriovenous fistula where a balloon catheter had failed to pass through the stenotic lesion after a guide wire had successfully passed. Native and Gore-tex fistula were used in 22 and eight cases, respectively.Sixteen stenoses were located in the central vein, and fourteen in the peripheral. The puncture sites used in order to perform the technique were the femoral vein in all cases of central stenosis; three basilic, four cephalic, and five femoral veins in cases of peripheral stenosis and one femoral and one radial artery in cases of anastomotic stenosis. The guide wire was passed through the stenotic lesion, pulled out using the snare technique, and then stretched in order to tighten it. The balloon catheter was then passed through the lesion and traditional balloon angioplasty was performed. The technical success rate and complications of the technique, and the patency rate of recanalized arteriovenous fistula, were evaluated. In 26 of the thirty patients, (86.7%), the procedure was technically successful. In the remaining four cases, failure was due to venous dissection (n=1), marked residual stenosis (n=2), or cardiac arrest (n=1) during the procedure. The average procedure time was 105 (range, 40-210) minutes, and in three cases rupture of the vein occurred. The patency rate of PTA was 80% (24/30) at four months, 63% (19/30) at six months, and 30% (9/30) at twelve months. The expected technical success rate of traditional PTA, without the Wire-Loop technique, would have been 79.3%, but using the technique, the rate increased to 86.7%. The Wire

  16. Role of interferon-γ on smooth muscle cells proliferation and migration after balloon injury by inhibiting transforming growth factor-β signal pathway

    Institute of Scientific and Technical Information of China (English)

    MEI Yu; WANG Gui-zhao; HUANG Yong-lin

    2003-01-01

    @@ Objective Restenosis after balloon angioplasty resuits from abnormal proliferation of phenotypically modulated vascular smooth muscle cells (SMCs) that migrate and synthesize large amounts of extracellular matrix. A vafety of growth factors have been shown to play a role in the development of restenotic lesions including transforming growth factor-β (TGF-β).

  17. [Subintimal angioplasty and diabetic foot revascularisation].

    Science.gov (United States)

    Pierret, Charles; Tourtier, Jean-Pierre; Bordier, Lise; Blin, Emmanuel; Duverger, Vincent

    2011-01-01

    Diabetic wounds foot are responsible for 5-10% minor or major amputation in France. In fact, amputation risk of lower limbs is 15-30% higher for diabetic patients. University of Texas classification (UT) is the reference for diabetic foot wound. It distinguish non ischemic and ischemic wound with more amputation. If ischaemia is combined, revascularization may be considered for salvage of the limb. Some revascularization techniques are well known: as surgical by-pass, angioplasty with or without stent, or hybrid procedures with the both. Subintimal angioplasty is a more recent endovascular technique, in assessment for old patients who are believed to be unsuitable candidates for conventional by-pass or angioplasty.

  18. Holmium:YAG laser angioplasty: treatment of acute myocardial infarction

    Science.gov (United States)

    Topaz, On

    1993-06-01

    We report our clinical experience with a group of 14 patients who presented with acute myocardial infarction. A holmium:YAG laser was applied to the infarct-related artery. This laser emits 250 - 600 mJ per pulse, with a pulse length of 250 microseconds and repetition rate of 5 Hz. Potential benefits of acute thrombolysis by lasers include the absence of systemic lytic state; a shortened thrombus clearing time relative to using thrombolytics; safe removal of the intracoronary thrombus and facilitation of adjunct balloon angioplasty. Potential clinical difficulties include targeting the obstructive clot and plaque, creation of debris and distal emboli and laser-tissue damage. It is conceivable that holmium:YAG laser can be a successful thrombolytic device as its wave length (2.1 microns) coincides with strong water absorption peaks. Since it is common to find an atherosclerotic plaque located under or distal to the thrombotic occlusion, this laser can also be applied for plaque ablation, and the patient presenting with acute myocardial infarction can clearly benefit from the combined function of this laser system.

  19. Small coronary vessel angioplasty: outcomes and technical considerations

    Directory of Open Access Journals (Sweden)

    Sudhir Rathore

    2010-10-01

    Full Text Available Sudhir RathoreDepartment of Cardiology, Atkinson Morley wing, St George’s Healthcare NHS Trust, London, UKAbstract: Small vessel (<3 mm coronary artery disease is common and has been identified as independent predictor of restenosis after percutaneous coronary intervention. It remains controversial whether bare-metal stent (BMS implantation in small vessels has an advantage over balloon angioplasty in terms of angiographic and clinical outcomes. Introduction of drug-eluting stent (DES has resulted in significant reduction in restenosis and the need for repeat revascularization. Several DESs have been introduced resulting in varying reduction in outcomes as compared with BMS. However, their impact on outcomes in small vessels is not clearly known. It is expected that DES could substantially reduce restenosis in smaller vessels. Large, randomized studies are warranted to assess the impact of different DESs on outcomes in patients with small coronary arteries.Keywords: small coronary arteries, coronary artery disease, stent, drug-eluting stent, restenosis 

  20. Percutaneous laser-assisted thermal coronary angioplasty in native coronary arteries and saphenous vein grafts: initial results and angiographic follow-up.

    Science.gov (United States)

    Linnemeier, T J; Rothbaum, D A; Cumberland, D C; Landin, R J; Hodes, Z I; Ball, M W

    1990-01-01

    Percutaneous laser-assisted thermal coronary angioplasty was attempted in 29 vessels (27 patients): 10 left anterior descending, 2 left circumflex and 17 mid-shaft (non-anastomotic) saphenous vein grafts. Argon or YAG laser thermal energy was applied via a 1.3, 1.6 or 1.9 mm metal capped probe followed by conventional balloon angioplasty in 27 vessels and sole thermal laser therapy in two vessels. The laser probe successfully crossed 83% (24/29) of vessels and subsequent balloon dilatation increased the success rate to 93% (25/27). Perforation occurred in a vein graft resulting in one in-hospital death post repeat emergency coronary artery bypass graft surgery. Angiographic follow-up was obtained in 85% (24/28) of vessels. Angiographic restenosis ( greater than 50% reduction in lumen diameter) occurred in 27% (3/11) of native coronary arteries and 62% (8/13) of saphenous vein grafts. Therefore, despite high initial success rates, the application of laser thermal energy with small laser probes relative to vessel size, followed by conventional balloon angioplasty, does not appear to alter restenosis. Further evaluation of coronary laser systems should be continued only with catheters that are capable of creating channels closer to the size of the vessel treated.

  1. Treatment of renovascular hypertension by transluminal angioplasty

    DEFF Research Database (Denmark)

    Øvrehus, Kristian A; Andersen, Poul E; Jacobsen, Ib A

    2007-01-01

    OBJECTIVE: The study is a follow-up on treatment of renovascular hypertension (RVH) with percutaneous transluminal renal angioplasty (PTRA). METHODS: Patients were screened on the basis of clinical criteria of increased probability of RVH with renography and in selected cases with renal vein renin...... stable. CONCLUSION: PTRA is an effective treatment of RVH in patients selected by signs of a flow-restricting stenosis. Twelve percent were normotensive after angioplasty and a further 77% had better controlled hypertension. Few complications were seen and renal function was on average unchanged...

  2. Balloon dacryocystoplasty study in the management of adult epiphora.

    LENUS (Irish Health Repository)

    Fenton, S

    2012-02-03

    PURPOSE: To determine the efficacy of dacryocystoplasty with balloon dilation in the treatment of acquired obstruction of the nasolacrimal system in adults. METHODS: Balloon dacryocystoplasty was performed in 52 eyes of 42 patients under general anaesthetic. A Teflon-coated guidewire was introduced through the canaliculus and manipulated through the nasolacrimal system and out of the nasal aperture. A 4 mm wide 3 cm coronary angioplasty balloon catheter was threaded over the guidewire in a retrograde fashion and dilated at the site of obstruction. RESULTS: There was complete obstruction in 30% of cases and partial obstruction in 70%. The most common site of obstruction was the nasolacrimal duct. The procedure was technically successful in 94% of cases. The overall re-obstruction rate was 29% within 1 year of the procedure. There was an anatomical failure rate of 17% for partial obstruction and 69% for complete obstruction within 1 year. CONCLUSIONS: Balloon dacryocystoplasty has a high recurrence rate. There may be a limited role for this procedure in partial obstructions. Further refinements of the procedure are necessary before it can be offered as a comparable alternative to a standard surgical dacryocystorhinostomy.

  3. Kinetic analysis of negative power deposition in low pressure plasmas

    CERN Document Server

    Trieschmann, Jan

    2016-01-01

    The negative power absorption in low pressure plasmas is investigated by means of an analyical model which couples Boltzmann's equation and the quasi-stationary Maxwell's equation. Exploiting standard Hilbert space methods an explicit solution for both, the electric field and the distribution function of the electrons for a bounded discharge configuration subject to an unsymmetrical excitation has been found for the first time. The model is applied to a low pressure inductively coupled plasma discharge. In this context particularly the anomalous skin effect and the effect of phase mixing is discussed. The analytical solution is compared with results from electromagnetic full wave particle in cell simulations. Excellent agreement between the analytical and the numerical results is found.

  4. Heat transfer by condensation of low pressure metal vapors.

    Science.gov (United States)

    Huang, Y. S.; Lyman, F. A.; Lick, W. J.

    1972-01-01

    The film condensation of low pressure metal vapors on isothermal vertical flat plates or tubes is considered. The liquid film is treated as a thin layer in which the acceleration and pressure forces are negligible and across which the temperature distribution is linear. The average behavior of the vapor is found from the linearized one-dimensional vapor flow equations. In order to calculate the rate of condensation, a consistent distribution function for the vapor particles at the liquid-vapor interface is necessary and is determined. The result of the analysis is a set of algebraic equations from which one can predict the condensation rate of low pressure metal vapors. A large but continuous temperature decrease in the vapor is predicted and calculated.

  5. The laser driven short-term heating balloon catheter: Relation between the chronic neointimal hyperplasia formation and thermal damage to arterial smooth muscle cells.

    Science.gov (United States)

    Shimazaki, Natsumi; Hayashi, Tomoaki; Kunio, Mie; Igami, Yuka; Arai, Tsunenori; Sakurada, Masami

    2010-01-01

    We proposed a novel laser-driven short-term heating angioplasty to realize restenosis-suppressive angioplasty for peripheral artery disease. In this study, we investigated the chronic intimal hyperplasia formation after the short-term heating dilatation in vivo, as well as the thermal damage calculation on arterial smooth muscle cells (SMCs). The prototype short-term heating balloon catheter with 5.0, 5.5, 6.0 mm φ in balloon diameter and 25 mm in balloon length were employed. The short-term heating dilatation was performed in porcine iliac arteries with dilatation conditions of 75°C (N=4) and 65°C (N=5) as peak balloon temperature, 18 ± 4s as heating duration, 3.5 atm as balloon dilatation pressure. Four weeks after the balloon dilatation, the balloon-dilated artery segments were extracted and were stained with HE and picrosirius red for histological observation. In the case of 75°C as the peak balloon temperature, neointimal hyperplasia formation was significantly reduced. In this case, the SMCs density in the artery media measured from the HE-stained specimen was 20% lower than that in the reference artery. According to the thermal damage calculation, it was estimated that the SMCs lethality in artery media after the short-term heating angioplasty was 20% in the case of 75°C as the peak balloon temperature. We demonstrated that the short-term heating dilatation reduced the number of SMCs in artery media. We think this SMCs reduction might contribute to the suppression of chronic neointimal hyperplasia.

  6. LOW-PRESSURE MEMBRANE CONTACTORS FOR CARBON DIOXIDE CAPTURE

    Energy Technology Data Exchange (ETDEWEB)

    Baker, Richard; Kniep, Jay; Hao, Pingjiao; Chan, Chi Cheng; Nguyen, Vincent; Huang, Ivy; Amo, Karl; Freeman, Brice; Fulton, Don; Ly, Jennifer; Lipscomb, Glenn; Lou, Yuecun; Gogar, Ravikumar

    2014-09-30

    This final technical progress report describes work conducted by Membrane Technology and Research, Inc. (MTR) for the Department of Energy (DOE NETL) on development of low-pressure membrane contactors for carbon dioxide (CO2) capture from power plant flue gas (award number DE-FE0007553). The work was conducted from October 1, 2011 through September 30, 2014. The overall goal of this three-year project was to build and operate a prototype 500 m2 low-pressure sweep membrane module specifically designed to separate CO2 from coal-fired power plant flue gas. MTR was assisted in this project by a research group at the University of Toledo, which contributed to the computational fluid dynamics (CFD) analysis of module design and process simulation. This report details the work conducted to develop a new type of membrane contactor specifically designed for the high-gas-flow, low-pressure, countercurrent sweep operation required for affordable membrane-based CO2 capture at coal power plants. Work for this project included module development and testing, design and assembly of a large membrane module test unit at MTR, CFD comparative analysis of cross-flow, countercurrent, and novel partial-countercurrent sweep membrane module designs, CFD analysis of membrane spacers, design and fabrication of a 500 m2 membrane module skid for field tests, a detailed performance and cost analysis of the MTR CO2 capture process with low-pressure sweep modules, and a process design analysis of a membrane-hybrid separation process for CO2 removal from coal-fired flue gas. Key results for each major task are discussed in the report.

  7. APHRON-BASED DRILLING FLUIDS: SOLUTION FOR LOW PRESSURE RESERVOIRS

    Directory of Open Access Journals (Sweden)

    Nediljka Gaurina-Međimurec

    2009-12-01

    Full Text Available Drilling wells throughout depleted or low pressure reservoirs requires low density drilling fluids, often with density less than water. Methods to reduce the density of drilling fluids have included mixing-in air or nitrogen. However, problems with these approaches include instability of gas bubbles (bubbles collapse or expand and increased costs. Recently, the use of micro bubbles named aphrons in drilling, completion and workover fluids has proven success in solving many problems related to low pressure reservoirs such as fluid loss control, formation damage, stabilization of multipressure sequences with one fluid and possible differential sticking. Aphrons represent bubble with uniquely structure stabilized with surfactant. Against conventional micro bubbles, aphrons are more stable in downhole conditions and they are generated using standard mixing equipment. Owing to their properties and overpressure in wellbore aphrons penetrate into low pressure layers and set up inner bridging. Depleted wells which are very expensive to drill underbalanced or with other remediation techniques can now be drilled overbalanced. This paper presents description of aphron structure and stability, aphron bridging mechanism, aphron-based fluid composition and properties, and field experiences in applying aphron-based fluids.

  8. Bulk characterization of pharmaceutical powders by low-pressure compression.

    Science.gov (United States)

    Sørensen, Arne Hagsten; Sonnergaard, Jørn Møller; Hovgaard, Lars

    2005-01-01

    Low-pressure compression of pharmaceutical powders using small amounts of sample (50 mg) was evaluated as an alternative to traditional bulk powder characterization by tapping volumetry. Material parameters were extrapolated directly from the compression data and by fitting with the Walker, the Kawakita, and the Log-Exp compression models. The compression-derived material parameters were compared to the poured and tapped density and the Compressibility Index determined by tapping. The repeatability of the compression-derived parameters was generally high, supporting their potential for characterization purposes. Significant correlation was demonstrated between several of the compression and tapping-derived parameters. The discriminative power of the low-pressure compression test was discussed using the compressed density at 0.2 MPa, correlated with the tapped density, and the relative Walker coefficient, correlated with the Compressibility Index, as examples. The compressed density at 0.2 MPa and the relative Walker coefficient demonstrated excellent discriminative power, superior to the discriminative power of the correlated tapping derived parameters. The low-pressure compression test was concluded to provide a cost-effective and sensitive alternative to traditional tapping volumetry.

  9. Low pressure gas collection system : solving environmental problems

    Energy Technology Data Exchange (ETDEWEB)

    Saputelli, L.A. [PDVSA Exploracion and Produccion (Venezuela)

    1998-09-01

    Alternative solutions to flaring for collecting low pressure gases in oil fields, were discussed. Many different solutions for boosting or collecting low pressure gases and mixing them into the oil stream were examined. A solution for collecting low pressure gases using existing field facilities was proposed. Main factors considered in designing this solution included: (1) the use of existing power facilities, (2) low up-scaling cost, (3) keeping harmony with the environment, and (4) maintaining well efficiencies. Field trials (conducted in 1982) consisted of the testing of 10 `Ecopres` compressors in the Bolivar coastal field, Lake Maracaibo, Venezuela, in order to maximize gas utilization. The tests showed that it was possible to recover up to 99 per cent of annular gas with no reduction in oil well productivity but there was a 21 per cent reduction in oil production when the annular flow was connected directly to the flow line. In the proposed alternative solution, annular spaces are open to atmospheric pressure. The proposed system consists of a single stage gas compressor attached to a heat exchanger and a single stage gas turbine. 4 refs., 9 figs.

  10. Paclitaxel-coated balloon fistuloplasty versus plain balloon fistuloplasty only to preserve the patency of arteriovenous fistulae used for haemodialysis (PAVE): study protocol for a randomised controlled trial.

    Science.gov (United States)

    Karunanithy, Narayan; Mesa, Irene Rebollo; Dorling, Anthony; Calder, Francis; Katsanos, Konstantinos; Semik, Vikki; Robinson, Emily; Peacock, Janet; Das, Neelanjan; Forman, Colin; Lawman, Sarah; Steiner, Kate; Wilkins, C Jason; Robson, Michael G

    2016-05-12

    The initial therapy for a stenosis in an arteriovenous fistula used for haemodialysis is radiological balloon dilatation or angioplasty. The benefit of angioplasty is often short-lived, intervention-free survival is reported to be 40-50 % at 1 year. Previous small studies and observational data suggest that paclitaxel-coated balloons may be of benefit in improving outcomes after fistuloplasty of stenotic arteriovenous fistulae. We have designed a multicentre, double-blind randomised controlled trial to test the superiority of paclitaxel-coated balloons for preventing restenosis after fistuloplasty in patients with a native arteriovenous fistula. Two hundred and eleven patients will be followed up for a minimum of 1 year. Inclusion criteria include a clinical indication for a fistuloplasty, an access circuit that is free of synthetic graft material or stents, and a residual stenosis of 30 % or less after plain balloon fistuloplasty. Exclusion criteria include a synchronous venous lesion in the same access circuit, location of the stenosis central to the thoracic inlet or a thrombosed access circuit at the time of treatment. The primary endpoint is time to end of target lesion primary patency. This is defined as a clinically-driven radiological or surgical re-intervention at the treatment segment, thrombosis that includes the treatment segment, or abandonment of the access circuit due to an inability to re-treat the treatment segment. Secondary endpoints include angiographic late lumen loss, time to end of access circuit cumulative patency, the total number of interventions, and quality of life. The trial is funded by the National Institute for Health Research. We anticipate that this trial will provide rigorous data that will determine the efficacy of additional paclitaxel-coated balloon fistuloplasty versus plain balloon fistuloplasty only to preserve the patency of arteriovenous fistulae used for haemodialysis. ISRCTN14284759 . Registered on 28 October 2015.

  11. Role of endovascular irradiation in the prevention of vascular restenosis following angioplasty; Role de la curietherapie endovasculaire dans la prevention de la restenose vasculaire apres angioplastie

    Energy Technology Data Exchange (ETDEWEB)

    Noel, G.; Feuvret, L.; Mazeron, J.J.; Pousset, F. [Hopital Pitie-Salpetriere, 75 - Paris (France); Bourhis, J.; Gerbaulet, A. [Institut Gustave Roussy, 94 - Villejuif (France); Popowski, Y. [Hopital Universitaire, Geneve (Switzerland)

    1998-07-01

    About 30% of patients who underwent percutaneous transluminal coronary angioplasty show evidence of restenosis, which appears to be independent of the angioplasty method used. The restenosis is due of two factors, Firstly migration of smooth vascular muscle cells of the vascular media to the intima and multiplication which lead to the formation of a neo-intima. Irradiation limits the proliferation by acting of the cells in the mitotic stage. The vascular target volume is not very thick and is difficult to define it, that why brachytherapy seems to be the best procedure to prevent restenosis. However, the development of this treatment present many difficulties. Different irradiation techniques have been studied. Such techniques include catheter containing radioactive sealed source, radioactive stent, or balloon containing radioactive liquid inside. Each of these methods have their own advantages, inconveniences, problems and risks. Radioisotope may be either beta or gamma emitters.Gamma emitter presents problems for radioprotection but the satisfactory dose distribution may be difficult to obtain using beta emitter. Choice of dose, dose rate and delay between the end of angioplasty and the beginning of brachytherapy is subject to some discuss. Animal experiments using radioisotope have shown reduction in cell proliferation. Human trials showed feasibility, safety of the method and real impact on restenosis prevention. However, long-term efficacy has not been proved because the follow-up of the patients is too short. A randomized trial of {sup 192}Ir brachytherapy for prevention of restenosis has recently shown the efficacy in short and median term. However, long term efficiency and secondary effects have not yet been established as the follow up time of this study is still too short. That is why, collaboration between cardiologists and radiotherapists and physicists is indispensable to enable the development of an optimal technique. (authors)

  12. Laser-driven short-duration heating angioplasty: chronic artery lumen patency and histology in porcine iliac artery

    Science.gov (United States)

    Shimazaki, Natsumi; Kunio, Mie; Naruse, Sho; Arai, Tsunenori; Sakurada, Masami

    2012-02-01

    We proposed a short-duration heating balloon angioplasty. We designed a prototype short-duration heating balloon catheter that can heat artery media to 60-70°C within 15-25 s with a combination of laser-driven heat generation and continuous fluid irrigation in the balloon. The purpose of this study was to investigate chronic artery lumen patency as well as histological alteration of artery wall after the short-duration heating balloon dilatation with porcine healthy iliac artery. The short-term heating balloon dilated sites were angiographically patent in acute (1 hour) and in chronic phases (1 and 4 weeks). One week after the dilatation, smooth muscle cells (SMCs) density in the artery media measured from H&E-stained specimens was approx. 20% lower than that in the reference artery. One and four weeks after the dilatations, normal structure of artery adventitia was maintained without any incidence of thermal injury. Normal lamellar structure of the artery media was also maintained. We found that the localized heating restricted to artery media by the short-duration heating could maintain adventitial function and artery normal structure in chronic phase.

  13. Coronary angioplasty for early postinfarction unstable angina

    NARCIS (Netherlands)

    P.J. de Feyter (Pim); P.W.J.C. Serruys (Patrick); A. Soward; M.J.B.M. van den Brand (Marcel); E. Bos (Egbert); P.G. Hugenholtz (Paul)

    1986-01-01

    textabstractCoronary angioplasty was performed in 53 patients in whom unstable angina had reoccurred after 48 hr and within 30 days after sustained myocardial infarction. Single-vessel disease was present in 64% of the patients and multivessel disease in 36%. The preceding myocardial infarction had

  14. Dose rate in intravascular radionuclide therapy using Re-188 coated balloon

    Energy Technology Data Exchange (ETDEWEB)

    Baek, M. Y.; Kim, J. K. [Hanyang Univ., Seoul (Korea, Republic of)

    2001-05-01

    Restenosis is the major drawback problem after percutaneous transluminal coronary angioplasty (PTCA). In order to reduce the restenosis, radionuclide therapy has been used, and these day balloon coating method with radionuclide is investigating to effective therapy. We intend to calculate the activity by Monte Carlo method, which is needed in the investigation of coated balloon using Re-188. We used EGSnrc code system to calculate this activity. Balloons were assumed be a length of 20 mm or 30 mm and to have a central catheter of diameter 0.5 mm. The surface of balloon is coated with 0.01 mm depth Re-188 using poly urethan. We calculated dose distribution as radial distance from the surface of balloon. And we calculate how much activities are needed to irradiate 18Gy at the 0.5 mm, 1.0 mm distance from balloon surface during 3 minutes. As results it is needed 19.3 mCi and 33.6 mCi relatively for each 0.5 mm and 1.0 mm in the 20 mm balloon. It is need 27.8 mCi and 48.3 mCi in the 30 mm balloon. Recent report for Ho-166 using EGS4 suggests 13.04 mCi at 0.5 mm distance in the 20 mm balloon. This value is lower than our result for Re-188 for the same size balloon. It is considered to be a systemic difference between two simulation codes ({approx}10%)

  15. New developments in the clinical use of drug-coated balloon catheters in peripheral arterial disease

    Directory of Open Access Journals (Sweden)

    Naghi J

    2016-06-01

    Full Text Available Jesse Naghi, Ethan A Yalvac, Ali Pourdjabbar, Lawrence Ang, John Bahadorani, Ryan R Reeves, Ehtisham Mahmud, Mitul Patel Division of Cardiovascular Medicine, Sulpizio Cardiovascular Center, University of California, San Diego, CA, USA Abstract: Peripheral arterial disease (PAD involving the lower extremity is a major source of morbidity and mortality. Clinical manifestations of PAD span the spectrum from lifestyle limiting claudication to ulceration and gangrene leading to amputation. Advancements including balloon angioplasty, self-expanding stents, drug-eluting stents, and atherectomy have resulted in high technical success rates for endovascular therapy in patients with PAD. However, these advances have been limited by somewhat high rates of clinical restenosis and clinically driven target lesion revascularization. The recent introduction of drug-coated balloon technology shows promise in limiting neointimal hyperplasia induced by vascular injury after endovascular therapies. This review summarizes the contemporary clinical data in the emerging area of drug-coated balloons. Keywords: drug-coated balloons, endovascular, percutaneous transluminal angioplasty, paclitaxel, peripheral arterial disease

  16. Ten-year follow-up of percutaneous transluminal coronary angioplasty for proximal left anterior descending coronary artery stenosis in 351 patients.

    Science.gov (United States)

    Ten Berg, J M; Gin, M T; Ernst, S M; Kelder, J C; Suttorp, M J; Mast, E G; Bal, E; Plokker, H W

    1996-07-01

    We sought to evaluate the short- and long-term results of balloon angioplasty for stenoses in the proximal left anterior descending coronary artery. Both the supposedly high rate of acute complications and relatively poor long-term results of balloon angioplasty for stenoses in the proximal left anterior descending coronary artery have led to a search for alternative interventional techniques. We analyzed the success rates and long-term follow-up results in 351 consecutive patients who underwent balloon angioplasty for stenosis of the left anterior descending coronary artery proximal to its first side branch. The power of the study was >80% in detecting a difference of 9% in the proportion of patients who survived at 10 years, assuming an 80% survival rate in the control group. There were 60 ostial and 291 nonostial stenoses. Follow-up lasted a median of 85 months (range 0 to 137) and was 100% complete. The angiographic success rate was 90.9%. The clinical success rate was 86.3%. Nine patients (2.6%) died, 17 (4.8%) needed emergency coronary artery bypass graft surgery, and 10 (2.8%) developed a myocardial infarction. Several patients had subsequent complications. The success and complication rates were not significantly different for patients with ostial and nonostial stenoses. Ten years after balloon angioplasty, freedom from mortality was 80%, freedom from cardiac death was 87%, freedom from myocardial infarction was 84%, freedom from vessel-related reinterventions was 66%, and freedom from angina pectoris was 33%. There were more reinterventions for ostial stenoses, with a 1-year relative risk of ostial versus nonostial stenoses for related reinterventions of 1.7 (95% confidence interval 1 to 2.8, p = 0.049). More than 10 years ago, balloon angioplasty for stenoses in the proximal left anterior descending coronary artery, either ostial or nonostial, had a high success rate. Although the long-term results are satisfactory, ostial stenoses are associated with a

  17. A wireless and passive low-pressure sensor.

    Science.gov (United States)

    Nicolay, Pascal; Lenzhofer, Martin

    2014-02-17

    This paper will discuss the results obtained with a first prototype of a completely passive and wireless low pressure sensor. The device is a heat conductivity gauge, based on a wireless and passive SAW temperature sensor. The required heating energy is applied to the sensor using inductive coupling. The prototype was successfully tested in a vacuum chamber. Its equilibrium temperature changed drastically and in a reproducible way when pressure steps were applied. However, the response time was very long. A model is provided to account for the sensor's behavior. It is then used to show that the response time could be strongly improved using basic design improvements. Further possible improvements are discussed.

  18. Global Instability and Control of Low-Pressure Turbine Flows

    Science.gov (United States)

    2006-03-31

    Methodos Numericos in Ingenieria 2005, Granada Y 3 rd Symposium on Global Flow Instability and Control September 2005 Crete, Greece. * AIAA San...valid OMB control number. PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ADDRESS. 1. REPORT DATE (DD-MM-YYYY) 2. REPORT TYPE 3. DATES COVERED (From - To...31-03-2006 Final 01-02-2003 To 31-12-2005 4. TITLE AND SUBTITLE 5a. CONTRACT NUMBER Global Instability and Control of Low Pressure Turbine Flows 5b

  19. Device for calibration of low pressure gauges development

    OpenAIRE

    Nikitović Ž.D.

    2002-01-01

    Vacuum system set-up is presented and used for calibration of pressure gauges in the region of rough vacuum, from 103 mbar to 10-1 mbar, with dry air. The capacitance manometer is used for the calibration of piezoresistant manometer, oil, mercury and mercury micrometers U manometers. The applicability of the experimental set-up and obtained results for the low pressure gauges calibration in the medium and high vacuum region is approved. It was shown how calibration of some cheaper pressure ga...

  20. Low pressure growth of cubic boron nitride films

    Science.gov (United States)

    Ong, Tiong P. (Inventor); Shing, Yuh-Han (Inventor)

    1997-01-01

    A method for forming thin films of cubic boron nitride on substrates at low pressures and temperatures. A substrate is first coated with polycrystalline diamond to provide a uniform surface upon which cubic boron nitride can be deposited by chemical vapor deposition. The cubic boron nitride film is useful as a substitute for diamond coatings for a variety of applications in which diamond is not suitable. any tetragonal or hexagonal boron nitride. The cubic boron nitride produced in accordance with the preceding example is particularly well-suited for use as a coating for ultra hard tool bits and abrasives, especially those intended to use in cutting or otherwise fabricating iron.

  1. Predicted thermal superluminescence in low-pressure air

    CERN Document Server

    Aramyan, A R; Galechyan, G A; Mangasaryan, N R; Nersisyan, H B

    2009-01-01

    It is shown that due to the dissociation of the molecular oxygen it is possible to obtain inverted population in low pressure air by heating. As a result of the quenching of the corresponding levels of the atomic oxygen the thermal superluminescent radiation is generated. It has been found that the threshold of the overpopulation is exceeded at the air temperature 2300-3000 K. Using this effect a possible mechanism for the generation of the flashes of the radiation in air observed on the airframe of the space shuttle during its descent and reentry in the atmosphere is suggested.

  2. Protonation enhancement by dichloromethane doping in low-pressure photoionization

    Science.gov (United States)

    Shu, Jinian; Zou, Yao; Xu, Ce; Li, Zhen; Sun, Wanqi; Yang, Bo; Zhang, Haixu; Zhang, Peng; Ma, Pengkun

    2016-12-01

    Doping has been used to enhance the ionization efficiency of analytes in atmospheric pressure photoionization, which is based on charge exchange. Compounds with excellent ionization efficiencies are usually chosen as dopants. In this paper, we report a new phenomenon observed in low-pressure photoionization: Protonation enhancement by dichloromethane (CH2Cl2) doping. CH2Cl2 is not a common dopant due to its high ionization energy (11.33 eV). The low-pressure photoionization source was built using a krypton VUV lamp that emits photons with energies of 10.0 and 10.6 eV and was operated at ~500–1000 Pa. Protonation of water, methanol, ethanol, and acetaldehyde was respectively enhanced by 481.7 ± 122.4, 197.8 ± 18.8, 87.3 ± 7.8, and 93.5 ± 35.5 times after doping 291 ppmv CH2Cl2, meanwhile CH2Cl2 almost does not generate noticeable ions itself. This phenomenon has not been documented in the literature. A new protonation process involving in ion-pair and H-bond formations was proposed to expound the phenomenon. The observed phenomenon opens a new prospect for the improvement of the detection efficiency of VUV photoionization.

  3. Low pressure storage of natural gas on activated carbon

    Science.gov (United States)

    Wegrzyn, J.; Wiesmann, H.; Lee, T.

    The introduction of natural gas to the transportation energy sector offers the possibility of displacing imported oil with an indigenous fuel. The barrier to the acceptance of natural gas vehicles (NGV) is the limited driving range due to the technical difficulties of on-board storage of a gaseous fuel. In spite of this barrier, compressed natural gas (CNG) vehicles are today being successfully introduced into the market place. The purpose of this work is to demonstrate an adsorbent natural gas (ANG) storage system as a viable alternative to CNG storage. It can be argued that low pressure ANG has reached near parity with CNG, since the storage capacity of CNG (2400 psi) is rated at 190 V/V, while low pressure ANG (500 psi) has reached storage capacities of 180 V/V in the laboratory. A program, which extends laboratory results to a full-scale vehicle test, is necessary before ANG technology will receive widespread acceptance. The objective of this program is to field test a 150 V/V ANG vehicle in FY 1994. As a start towards this goal, carbon adsorbents have been screened by Brookhaven for their potential use in a natural gas storage system. This paper reports on one such carbon, trade name Maxsorb, manufactured by Kansai Coke under an Amoco license.

  4. Protonation enhancement by dichloromethane doping in low-pressure photoionization

    CERN Document Server

    Shu, Jinian; Xu, Ce; Li, Zhen; Sun, Wanqi; Yang, Bo; Zhang, Haixu; Zhang, Peng; Ma, Pengkun

    2016-01-01

    Doping has been used to enhance the ionization efficiency of analytes in atmospheric pressure photoionization, which is based on charge exchange. Compounds with excellent ionization efficiencies are usually chosen as dopants. In this paper, we report a new phenomenon observed in low-pressure photoionization: Protonation enhancement by dichloromethane (CH2Cl2) doping. CH2Cl2 is not a common dopant due to its high ionization energy (11.33 eV). The low-pressure photoionization source was built using a krypton VUV lamp that emits photons with energies of 10.0 and 10.6 eV and was operated at 500-1000 Pa. Protonation of water, methanol, ethanol, and acetaldehyde was respectively enhanced by 481.7 +/- 122.4, 197.8 +/- 18.8, 87.3 +/- 7.8, and 93.5 +/- 35.5 times after doping 291 ppmv CH2Cl2, meanwhile CH2Cl2 almost does not generate noticeable ions itself. This phenomenon has not been documented in the literature. A new protonation process involving in ion-pair and H-bond formations was proposed to expound the phenom...

  5. Cutting balloon for in-stent restenosis: acute and long-term results.

    Science.gov (United States)

    Rahel, Braim M; Suttorp, Maarten Jan; ten Berg, Jurrien M; Bal, Egbert T; Ernst, Sjef M P G; Rensing, Benno J; Kelder, Johannes C; Plokker, H W Thijs

    2004-08-01

    Conventional percutaneous coronary intervention for the treatment of in-stent restenosis (ISR) has shown a high rate of ISR (30-55%). Considering the need for both extrusion of hyperplastic intima and additional stent expansion, a cutting balloon might be more effective for the treatment of ISR. We prospectively assessed the immediate and 8-month outcome of balloon angioplasty using the Barath Cutting Balloon in 100 consecutive patients (mean age: 60.5 +/- 10.8 years, 71% male). In 73 lesions (73%), a good result was reached with the cutting balloon only. In 21 lesions (21%) postdilatation and in 6 lesions (6%) predilatation with a conventional balloon was necessary. The mean inflation pressure was 8.7 +/- 2.0 (range: 6.0-18.0) atm. Before the procedure the mean minimal luminal diameter (MLD) was 0.95 +/- 0.45 mm. Quantitative coronary analysis showed a mean diameter stenosis of 65%+/- 16%. Immediately after the procedure the mean MLD was 2.42 +/- 0.54 mm with a mean diameter stenosis of 19%+/- 13%. Two patients died during the follow-up period (1 stroke, 1 nonvascular). At 8-month follow-up 26 patients (26%) reported to have anginal complaints CCS class II-IV of whom 16 (16%) needed target lesion revascularization. Treatment of ISR using the Barath Cutting Balloon can be performed safely with good immediate results and a relatively low need for repeated target lesion revascularization at 8-month follow-up.

  6. [Femoral angioplasty. Long-term results].

    Science.gov (United States)

    Foucart, H; Carlier, C; Baudrillard, J C; Joffre, F; Cécile, J P

    1990-01-01

    A study on the long-term efficacy of femoral-popliteal angioplasty was carried out on 185 angioplasty cases over a 5 year follow-up period. A classification of data according to the type of lesion treated, revealed that results were favorable in case of stenosis (87%), short obstruction (70%) and long obstruction (35%). A special study of the outcome of treatments for stage IV arteritis was carried out. After comparing results with those obtained by other teams, the authors list the complications encountered, hematomas, and thromboses, and show their current tendency for regression. Lastly, the authors stress the advantages of angioscopy, which permits to identify the nature of the treated lesions and to predict possible complications, which are usually underrated by angiography.

  7. A pilot study of coronary angioplasty in outpatients.

    OpenAIRE

    Laarman, G.J.; Kiemeneij, F.; van der Wieken, L R; Tijssen, J.G.; Suwarganda, J S; Slagboom, T.

    1994-01-01

    BACKGROUND--Is it safe to discharge patients from hospital on the same day as percutaneous transluminal coronary angioplasty (PTCA)? The hypothesis tested was that careful pre and post angioplasty selection of patients can identify a group that is at very low risk of postprocedural complications and that these patients may be discharged on the day of the procedure. METHODS--63 patients undergoing limited risk coronary angioplasty of 72 lesions were studied. So that patients would be able to w...

  8. Performance assessment of low pressure nuclear thermal propulsion

    Science.gov (United States)

    Gerrish, Harrold P., Jr.; Doughty, Glen E.

    1993-01-01

    An increase in Isp for nuclear thermal propulsion systems is desirable for reducing the propellant requirements and cost of future applications, such as the Mars Transfer Vehicle. Several previous design studies have suggested that the Isp could be increased substantially with hydrogen dissociation/recombination. Hydrogen molecules (H2), at high temperatures and low pressures, will dissociate to monatomic hydrogen (H). The reverse process (i.e., formation of H2 from H) is exothermic. The exothermic energy in a nozzle increases the kinetic energy and therefore, increases the Isp. The low pressure nuclear thermal propulsion system (LPNTP) system is expected to maximize the hydrogen dissociation/recombination and Isp by operating at high chamber temperatures and low chamber pressures. The process involves hydrogen flow through a high temperature, low pressure fission reactor, and out a nozzle. The high temperature (approximately 3000 K) of the hydrogen in the reactor is limited by the temperature limits of the reactor material. The minimum chamber pressure is about 1 atm because lower pressures decrease the engines thrust to weight ratio below acceptable limits. This study assumes that hydrogen leaves the reactor and enters the nozzle at the 3000 K equilibrium dissociation level. Hydrogen dissociation in the reactor does not affect LPNTP performance like dissociation in traditional chemical propulsion systems, because energy from the reactor resupplies energy lost due to hydrogen dissociation. Recombination takes place in the nozzle due primarily to a drop in temperature as the Mach number increases. However, as the Mach number increases beyond the nozzle throat, the static pressure and density of the flow decreases and minimizes the recombination. The ideal LPNTP Isp at 3000 K and 10 psia is 1160 seconds due to the added energy from fast recombination rates. The actual Isp depends on the finite kinetic reaction rates which affect the amount of monatomic hydrogen

  9. Development of a balloon volume sensor for pulsating balloon catheters.

    Science.gov (United States)

    Nolan, Timothy D C; Hattler, Brack G; Federspiel, William J

    2004-01-01

    Helium pulsed balloons are integral components of several cardiovascular devices, including intraaortic balloon pumps (IABP) and a novel intravenous respiratory support catheter. Effective use of these devices clinically requires full inflation and deflation of the balloon, and improper operating conditions that lead to balloon under-inflation can potentially reduce respiratory or cardiac support provided to the patient. The goal of the present study was to extend basic spirographic techniques to develop a system to dynamically measure balloon volumes suitable for use in rapidly pulsating balloon catheters. The dynamic balloon volume sensor system (DBVSS) developed here used hot wire anemometry to measure helium flow in the drive line from console to catheter and integrated the flow to determine the volume delivered in each balloon pulsation. An important component of the DBVSS was an algorithm to automatically detect and adjust flow signals and measured balloon volumes in the presence of gas composition changes that arise from helium leaks occurring in these systems. The DBVSS was capable of measuring balloon volumes within 5-10% of actual balloon volumes over a broad range of operating conditions relevant to IABP and the respiratory support catheter. This includes variations in helium concentration from 70-100%, pulsation frequencies from 120-480 beats per minute, and simulated clinical conditions of reduced balloon filling caused by constricted vessels, increased driveline, or catheter resistance.

  10. Costs and effectiveness of using coumarins before, during and after coronary angioplasty.

    Science.gov (United States)

    ten Berg, Jurrien M; Kelder, Johannas C; Plokker, Thys H W; van Hout, Ben A

    2002-01-01

    In the Balloon Angioplasty and Anticoagulation Study (BAAS), coumarins added to routine aspirin therapy before coronary angioplasty reduced cardiac events at the cost of a slightly higher risk of bleeding complications. To determine the cost effectiveness of coumarin treatment, based on the occurrence of both cardiac and bleeding events. Effectiveness was measured, applying two definitions, in terms of the number of events occurring at one year. In the first definition, the occurrence of death, myocardial infarction (MI), or stroke was assessed. The second definition also included revascularisations and major bleeding episodes as an event. Costs were limited to direct medical costs. Cost effectiveness was addressed by probability ellipses representing the point estimates and uncertainties surrounding both costs and effectiveness. At 1 year, death, MI or stroke occurred 1.1% less often when treating with aspirin plus coumarins rather than aspirin therapy alone. When revascularisations and major bleeding events were also included, the difference was 5.0%. Overall, the additional costs in relation to coumarin treatment were compensated by a reduction in repeat interventions. When including all costs, the savings associated with coumarin treatment were estimated at Euros 235 per patient after 1 year. The probability that coumarins are cost saving was estimated at 0.85. The probability that coumarins combine additional effectiveness with cost savings was estimated at 0.70 when survival free of MI or stroke as an effectiveness measure was considered, and at 0.83 when survival free of MI, stroke, revascularisation or major bleeding was considered. Coumarin therapy added to routine aspirin therapy before coronary angioplasty, and continued during follow-up, may not only be considered more effective but also cost saving relative to aspirin therapy alone.

  11. Short and long term outcomes of primary angioplasty in patients aged 75 years and over

    Directory of Open Access Journals (Sweden)

    Turgay Işık

    2011-06-01

    Full Text Available The treatment of elderly patients with ST segment elevated myocardial infarction (STEMI remains controversial. This study aimed to investigate the effects of primary angioplasty in elderly patients on in-hospital and long term major adverse cardiac events (MACE.Materials and methods: From October 2003 to March 2008, we retrospectively enrolled 220 patients aged 75 years and over with STEMI who underwent primary angioplasty. Patients’ characteristics, in-hospital and long term events were recorded.Results: Male/Female ratio of patients was 129/91 and mean age was 78.7 ± 3.6 (range, 75-97 years, and 58.6% of male. Of these patients 29.2% were diabetics, 69.8% were hypertensive, 34.4% were smoker and 43.5% were anemic at admission. Anterior myocardial infarction was diagnosed in 52.3% of patients. Mean pain-balloon time was 222 ± 116 minutes. Eighty two (38.2% of these 220 patients had three-vessel disease and 12 (5.7% were diagnosed as cardiogenic shock. Procedural success was observed in 79.6% of patients. Heart failure was observed 27.7% in hospital and intra aortic pump was used in 14.5% of patients. There was no significant difference between age groups in long term major cardiac events and in hospital mortality. Diabetes, leukocyte count at admission and in hospital heart failure were independent predictors of short term MACE and low hemoglobin level at admission and peak CKMB levels were independent predictors of long term MACE.Conclusions: Primary angioplasty in patients aged 75 years and over seems to be associated with low procedural complication, high procedural success, improved short and long term survival.

  12. Primary coronary angioplasty for acute myocardial infarction (the Primary Angioplasty Registry).

    Science.gov (United States)

    O'Neill, W W; Brodie, B R; Ivanhoe, R; Knopf, W; Taylor, G; O'Keefe, J; Grines, C L; Weintraub, R; Sickinger, B G; Berdan, L G

    1994-04-01

    During a 14-month period, 6 experienced centers prospectively enrolled 271 patients into a registry in which percutaneous transluminal coronary angioplasty was the primary treatment for acute myocardial infarction. Patients age > 18 years who presented with ST-segment elevation on the 12-lead electrocardiogram were enrolled if symptom duration was or = 2 units of blood occurred in 46 patients (18%); 14 of these transfusions were related to coronary artery bypass surgery. Primary angioplasty is associated with a high reperfusion rate, low in-hospital mortality and few recurrent myocardial ischemic events. These results point to the need for a large-scale trial comparing angioplasty with thrombolytic therapy in the setting of acute myocardial infarction.

  13. Universal stratospheric balloon gradiometer

    Science.gov (United States)

    Tsvetkov, Yury; Filippov, Sergey; Brekhov, Oleg; Nikolaev, Nikolay

    The study of the interior structure of the Earth and laws of its evolution is one of the most difficult problems of natural science. Among the geophysical fields the anomaly magnetic field is one of the most informational in questions of the Earth’s crust structure. Many important parameters of an environment are expedient for measuring at lower altitudes, than satellite ones. So, one of the alternatives is stratospheric balloon survey. The balloon flight altitudes cover the range from 20 to 50 km. At such altitudes there are steady zone air flows due to which the balloon flight trajectories can be of any direction, including round-the-world (round-the-pole). For investigation of Earth's magnetic field one of the examples of such sounding system have been designed, developed and maintained at IZMIRAN and MAI during already about 25 years. This system consists of three instrumental containers uniformly placed along a vertical 6 km line. Up today this set has been used only for geomagnetic purposes. So we describe this system on example of the measuring of the geomagnetic field gradient. System allows measuring a module and vertical gradient of the geomagnetic field along the whole flight trajectory and so one’s name is - stratospheric balloon magnetic gradiometer (SMBG). The GPS-receivers, located in each instrumental container, fix the flight coordinates to within several tens meters. Process of SBMG deployment, feature of the exit of rope from the magazine at the moment of balloon launching has been studied. Used magazine is cellular type. The hodograph of the measuring base of SBMG and the technique of correction of the deviations of the measuring base from the vertical line (introduction of the amendments for the deviation) during the flight have been investigated. It is shown that estimation of the normal level of values of the vertical gradient of the geomagnetic field is determined by the accuracy of determining the length of the measuring base SBMG

  14. Mars Solar Balloon Lander Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The Mars Solar Balloon Lander (MSBL) is a novel concept which utilizes the capability of solar-heated hot air balloons to perform soft landings of scientific...

  15. Venus Altitude Cycling Balloon Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The ISTAR Group ( IG) and team mate Thin Red Line Aerospace (TRLA) propose a Venus altitude cycling balloon (Venus ACB), an innovative superpressure balloon...

  16. A successful experimental model for intimal hyperplasia prevention using a resveratrol-delivering balloon.

    Science.gov (United States)

    Tolva, Valerio; Mazzola, Silvia; Zerbi, Pietro; Casana, Renato; Albertini, Mariangela; Calvillo, Laura; Selmin, Francesca; Cilurzo, Francesco

    2016-03-01

    Restenosis due to intimal hyperplasia is a major clinical problem that compromises the success of angioplasty and endovascular surgery. Resveratrol (RSV) has demonstrated a beneficial effect on restenosis from angioplasty. Unfortunately, the physicochemical characteristics of RSV reduce the practicality of its immediate clinical application. This work proposes an experimental model aiming to setup an intravessel, elutable, RSV-containing compound. A 140 μg/mL RSV sterile injectable solution with a suitable viscosity for intravascular administration by drug-delivery catheter (RSV-c) was prepared. This solution was locally administered in the common iliac artery of adult male New Zealand White rabbits using a dedicated device (Genie; Acrostak, Geneva, Switzerland) after the induction of intimal hyperplasia by traumatic angioplasty. The RSV concentrations in the wall artery were determined, and the thickness of the harvested iliac arteries was measured over a 1-month period. The Genie catheter was applied in rabbit vessels, and the local delivery resulted in an effective reduction in restenosis after plain angioplasty. Notably, RSV-c forced into the artery wall by balloon expansion might accumulate in the interstitial areas or within cells, avoiding the washout of solutions. Magnification micrographs showed intimal proliferation was significantly inhibited when RSV-c was applied. Moreover, no adverse events were documented in in vitro or in vivo studies. RSV can be advantageously administered in the arterial walls by a drug-delivery catheter to reduce the risk of restenosis. Copyright © 2016 Society for Vascular Surgery. Published by Elsevier Inc. All rights reserved.

  17. Electron heating in low pressure capacitive discharges revisited

    Science.gov (United States)

    Kawamura, E.; Lieberman, M. A.; Lichtenberg, A. J.

    2014-12-01

    The electrons in capacitively coupled plasmas (CCPs) absorb energy via ohmic heating due to electron-neutral collisions and stochastic heating due to momentum transfer from high voltage moving sheaths. We use Particle-in-Cell (PIC) simulations to explore these heating mechanisms and to compare the PIC results with available theories on ohmic and stochastic heating. The PIC results for ohmic heating show good agreement with the ohmic heating calculation of Lafleur et al. [Phys. Plasmas 20, 124503 (2013)]. The PIC results for stochastic heating in low pressure CCPs with collisionless sheaths show good agreement with the stochastic heating model of Kaganovich et al. [IEEE Trans. Plasma Sci. 34, 696 (2006)], which revises the hard wall asymptotic model of Lieberman [IEEE Trans. Plasma Sci. 16, 638 (1988)] by taking current continuity and bulk oscillation into account.

  18. Low pressure powder injection moulding of stainless steel powders

    Energy Technology Data Exchange (ETDEWEB)

    Zampieron, J.V.; Soares, J.P.; Mathias, F.; Rossi, J.L. [Powder Processing Center CCP, Inst. de Pesquisas Energeticas e Nucleares, Sao Paulo, SP (Brazil); Filho, F.A. [IPEN, Inst. de Pesquisas Energeticas e Nucleares, Cidade Univ., Sao Paulo, SP (Brazil)

    2001-07-01

    Low-pressure powder injection moulding was used to obtain AISI 316L stainless steel parts. A rheological study was undertaken using gas-atomised powders and binders. The binders used were based on carnauba wax, paraffin, low density polyethylene and microcrystalline wax. The metal powders were characterised in terms of morphology, particle size distribution and specific surface area. These results were correlated to the rheological behaviour. The mixture was injected in the shape of square bar specimens to evaluate the performance of the injection process in the green state, and after sintering. The parameters such as injection pressure, viscosity and temperature were analysed for process optimisation. The binders were thermally removed in low vacuum with the assistance of alumina powders. Debinding and sintering were performed in a single step. This procedure shortened considerably the debinding and sintering time. (orig.)

  19. Numerical simulation of low pressure die-casting aluminum wheel

    Institute of Scientific and Technical Information of China (English)

    Mi Guofa; Liu Xiangyu; Wang Kuangfei; Fu Hengzhi

    2009-01-01

    The FDM numerical simulation software, ViewCast system, was employed to simulate the low pressure die casting (LPDC) of an aluminum wheel. By analyzing the mold-filling and solidification stage of the LPDC process, the distribution of liquid fraction, temperature field and solidification pattern of castings were studied. The potential shrinkage defects were predicted to be formed at the rim/spoke junctions, which is in consistence with the X-ray detection result. The distribution pattern of the defects has also been studied. A solution towards reducing such defects has been presented. The cooling capacity of the mold was improved by installing water pipes both in the side mold and the top mold. Analysis on the shrinkage defects under forced cooling mode proved that adding the cooling system in the mold is an effective method for reduction of shrinkage defects.

  20. Low-Pressure Turbine Separation Control: Comparison With Experimental Data

    Science.gov (United States)

    Garg, Vijay K.

    2002-01-01

    The present work details a computational study, using the Glenn HT code, that analyzes the use of vortex generator jets (VGJs) to control separation on a low-pressure turbine (LPT) blade at low Reynolds numbers. The computational results are also compared with the experimental data for steady VGJs. It is found that the code determines the proper location of the separation point on the suction surface of the baseline blade (without any VGJ) for Reynolds numbers of 50,000 or less. Also, the code finds that the separated region on the suction surface of the blade vanishes with the use of VGJs. However, the separated region and the wake characteristics are not well predicted. The wake width is generally over-predicted while the wake depth is under-predicted.

  1. A Wireless and Passive Low-Pressure Sensor

    Directory of Open Access Journals (Sweden)

    Pascal Nicolay

    2014-02-01

    Full Text Available This paper will discuss the results obtained with a first prototype of a completely passive and wireless low pressure sensor. The device is a heat conductivity gauge, based on a wireless and passive SAW temperature sensor. The required heating energy is applied to the sensor using inductive coupling. The prototype was successfully tested in a vacuum chamber. Its equilibrium temperature changed drastically and in a reproducible way when pressure steps were applied. However, the response time was very long. A model is provided to account for the sensor’s behavior. It is then used to show that the response time could be strongly improved using basic design improvements. Further possible improvements are discussed.

  2. Very low pressure high power impulse triggered magnetron sputtering

    Science.gov (United States)

    Anders, Andre; Andersson, Joakim

    2013-10-29

    A method and apparatus are described for very low pressure high powered magnetron sputtering of a coating onto a substrate. By the method of this invention, both substrate and coating target material are placed into an evacuable chamber, and the chamber pumped to vacuum. Thereafter a series of high impulse voltage pulses are applied to the target. Nearly simultaneously with each pulse, in one embodiment, a small cathodic arc source of the same material as the target is pulsed, triggering a plasma plume proximate to the surface of the target to thereby initiate the magnetron sputtering process. In another embodiment the plasma plume is generated using a pulsed laser aimed to strike an ablation target material positioned near the magnetron target surface.

  3. Low-pressure hydrogen plasmas explored using a global model

    Science.gov (United States)

    Samuell, Cameron M.; Corr, Cormac S.

    2016-02-01

    Low-pressure hydrogen plasmas have found applications in a variety of technology areas including fusion, neutral beam injection and material processing applications. To better understand these discharges, a global model is developed to predict the behaviour of electrons, ground-state atomic and molecular hydrogen, three positive ion species (H+, \\text{H}2+ , and \\text{H}3+ ), a single negative ion species (H-), and fourteen vibrationally excited states of molecular hydrogen ({{\\text{H}}2}≤ft(\\upsilon =1\\right. -14)). The model is validated by comparison with experimental results from a planar inductively coupled GEC reference cell and subsequently applied to the MAGPIE linear helicon reactor. The MAGPIE reactor is investigated for a range of pressures from 1 to 100 mTorr and powers up to 5 kW. With increasing power between 50 W and 5 kW at 10 mTorr the density of all charged species increases as well as the dissociative fraction while the electron temperature remains almost constant at around 3 eV. For gas pressures from 1-100 mTorr at an input power of 1 kW, the electron density remains almost constant, the electron temperature and dissociative fraction decreases, while \\text{H}3+ density increases in density and also dominates amongst ion species. Across these power and pressure scans, electronegativity remains approximately constant at around 2.5%. The power and pressure determines the dominant ion species in the plasma with \\text{H}3+ observed to dominate at high pressures and low powers whereas H+ tends to be dominant at low pressures and high powers. A sensitivity analysis is used to demonstrate how experimental parameters (power, pressure, reactor wall material, geometry etc) influence individual species’ density as well as the electron temperature. Physical reactor changes including the length, radius and wall recombination coefficient are found to have the largest influence on outputs obtained from the model.

  4. [Baloon angioplasty with stent implantation in recoarctation of the aorta: an attractive alternative].

    Science.gov (United States)

    Saliba, Z; Aggoun, Y; Iserin, L; Massih, T A; Bonnet, D; Acar, P; Mousseaux, E; Sidi, D; Kachaner, J; Bonhoeffer, P

    2001-05-01

    The results of transcatheter balloon angioplasty in teenagers and adults with aortic recoarctation are uncertain. Therefore, there is a current trend to prefer a more complex procedure including the implantation of a stent. This study deals with 8 patients aged 7 to 25.3 years (median: 15 years), weighing 20 to 68 kg. (median: 57) and having undergone resection of an aortic coarctation during infancy (24 days to 4 years). All had their lower limb pulses diminished or abolished, elevated blood pressure at rest (and at exercise in the 5 tested patients), and left ventricular hypertrophy. MRI documented the lesion and helped to select seven patients whose stenosis was short and remote enough from the origin of the main aortic collateral. In one case, the decision to stent was taken as an emergent measure to treat an aortic dissection which appeared shortly after balloon dilatation. The effectiveness of the procedure was immediate in all patients with a 50% increase in diameter of the dilated area, total relief of the gradient, drop to normal values of the blood pressure. These good results persisted at follow-up (3-24 months) in 6 patients, with moderate hypertensive rebounds in the last 2. There were 2 technical problems (premature burst of the balloon, asymmetrical inflation of the stent like an "Eiffel Tower") that could finally be overcome and should no longer occur with the new specially designed so-called "BIB" balloons. Would long term follow-up confirm these early results, one should conclude that this method offers an attractive, safe and effective option to surgery for adolescents and adults with late recoarctation of the aorta.

  5. Development of novel short-term heating angioplasty: thermal denaturation dynamics of collagen in artery wall

    Science.gov (United States)

    Shimazaki, N.; Tokunaga, H.; Katou, Y.; Hayashi, T.; Arai, T.

    2009-02-01

    We have studied to develop the new thermal angioplasty methodology, photo-thermo dynamic balloon angioplasty (PTDBA), which provides artery dilatation with short-term (collagen in artery media may be the important factor to attain sufficient artery dilatation for the PTDBA. In order to predict the optimum heating condition i.e. the balloon temperature and heating duration, we investigated the thermal denaturation dynamics of artery collagen in ex vivo. The extracted fresh porcine carotid artery was used. The temperature-dependent light scattering property and mechanical property of the artery specimen were simultaneously measured during artery temperature rising by specially made setup to assess the denaturation of arterial collagen. The change rate of the backscattered light intensity from the artery specimen; I(T)/I0 with 633nm was measured to evaluate the artery scattering property change with the thermal denaturation. The artery specimen was heated from 25°C to 80°C with constant temperature rising rate of 3°C/min. The measured I(T)/I0 was suddenly increased over 48°C. This boundary temperature might be the initiation temperature of the arterial collagen denaturation. We defined the variation of the I(T)/I0 as the collagen denaturation ratio, and calculated the reactive enthalpy by the chemical equilibrium theory. Since the calculated enthalpy was similar to the enthalpy in literature report, the variety of I(T)/I0 during the temperature rising might be attributed to the collagen conformational change due to the denaturation. In terms of the artery internal force measurement, the artery force was decreased with increasing of the artery temperature up to 65°C (i.e. softening), and increased over 65°C (i.e. shrinkage). We confirmed that the changes of the backscattered light (at 633nm in wavelength) from the artery might represent the artery collagen thermal denaturation degree.

  6. How does subintimal angioplasty compare to transluminal angioplasty for the treatment of femoral occlusive disease?

    Science.gov (United States)

    Klimach, S G; Gollop, N D; Ellis, J; Cathcart, P

    2014-01-01

    A best evidence topic in surgery was written according to a structured protocol. The question addressed how subintimal angioplasty (SIA) compares to transluminal angioplasty (TA) for the treatment of femoral occlusive disease. One hundred and thirty two papers were found using the reported search; the 5 which represented the best evidence to answer the question are discussed. The evidence on this subject is limited; there are no randomised controlled trials (RCTs) comparing SIA to TA for pathologically equivalent lesions. However SIA remains a safe and effective alternative to surgical bypass grafting when TA cannot be performed.

  7. Intraoperative Balloon Angioplasty Using Fogarty Artertial Embolectomy Balloon Catheter for Creation of Arteriovenous Fistula for Hemodialysis: Single Center Experience

    National Research Council Canada - National Science Library

    Moran Jin; Young Chul Yoon; Jin Hong Wi; Yang-Haeng Lee; Il-Yong Han; Kyung-Taek Park

    2015-01-01

    ...) created for hemodialysis access. Methods: A total of 156 patients who underwent creation of an AVF were divided into two groups, based whether a Fogarty catheter was used during AVF creation. Group A (89 patients...

  8. Ballon angioplasty and stenting for acute ischemic stroke%急性缺血性卒中患者的球囊血管成形和支架置入术治疗

    Institute of Scientific and Technical Information of China (English)

    石明超; 王守春

    2009-01-01

    药物溶栓治疗急性缺血性卒中存在一定的局限性,球囊血管成形和支架置入术已成为急性缺血性卒中治疗的研究热点.文章综述了球囊血管成形和支架置入术治疗急性缺血性卒中的有效性和安全性.%Thrombolytic agents for the treatment of acute ischemic stroke have some limitations. Balloon angioplasty and stenting have become the research hotspot in the treatment of acute ischemic stroke. 1his article reviews the effectiveness and safety of balloon angioplasty and stenting in the treatment of acute ischemic stroke.

  9. Oral anticoagulant therapy during and after coronary angioplasty the intensity and duration of anticoagulation are essential to reduce thrombotic complications.

    Science.gov (United States)

    ten Berg, J M; Hutten, B A; Kelder, J C; Verheugt, F W; Plokker, H W

    2001-04-24

    In the randomized Balloon Angioplasty and Anticoagulation Study (BAAS), the addition of oral anticoagulants to aspirin significantly reduced early and late events after coronary angioplasty. However, bleeding episodes were increased. The present report studied the intensity and the duration of anticoagulation as predictors of thrombotic and bleeding events. A total of 530 patients, 34% of whom received a stent, were treated with aspirin plus coumarins. Half of the patients were randomized to angiographic follow-up. The target international normalized ratio (INR) was 2.1 to 4.8 during angioplasty and 6-month follow-up. Thrombotic events were death, myocardial infarction, target lesion revascularization, and thrombotic stroke. Bleeding complications were hemorrhagic stroke, major extracranial bleeding, and false aneurysm. "Optimal" anticoagulation was defined as an INR in the target range for at least 70% of the follow-up time. There were 17 early thrombotic events (3.2%), 7 early bleeding episodes (1.3%), and 10 false aneurysms (1.9%). The incidence rate for both early thrombotic and bleeding events was lowest in patients in the target range. A total of 61 late thrombotic events occurred (11.6%). Optimal anticoagulation was an independent predictor of late thrombotic events (relative risk, 0.33; 95% CI, 0.19 to 0.57) and was associated with a 0.21 mm (95% CI, 0.17 to 0.42) larger vessel lumen at 6 months. Late bleeding episodes (1.4%) were lowest in patients in the target range. Coumarins started before coronary angioplasty with a target INR of 2.1 to 4.8 led to the lowest procedural event rate, without an increase in bleeding episodes. During follow-up, optimal anticoagulation was associated with a decrease in the incidence of late events by 67% and a significant improvement in 6-month angiographic outcome.

  10. Thermodynamic analysis of cascade microcryocoolers with low pressure ratios

    Energy Technology Data Exchange (ETDEWEB)

    Radebaugh, Ray [National Institute of Standards and Technology, Boulder, Colorado 80305 (United States)

    2014-01-29

    The vapor-compression cycle for refrigeration near ambient temperature achieves high efficiency because the isenthalpic expansion of the condensed liquid is a rather efficient process. However, temperatures are limited to about 200 K with a single-stage system. Temperatures down to 77 K are possible with many stages. In the case of microcryocoolers using microcompressors, pressure ratios are usually limited to about 6 or less. As a result, even more stages are required to reach 77 K. If the microcompressors can be fabricated with low-cost wafer-level techniques, then the use of many stages with separate compressors may become a viable option for achieving temperatures of 77 K with high efficiency. We analyze the ideal thermodynamic efficiency of a cascade Joule-Thomson system for various temperatures down to 77 K and with low pressure ratios. About nine stages are required for 77 K, but fewer stages are also analyzed for operation at higher temperatures. For 77 K, an ideal second-law efficiency of 83 % of Carnot is possible with perfect recuperative heat exchangers and 65 % of Carnot is possible with no recuperative heat exchangers. The results are compared with calculated efficiencies in mixed-refrigerant cryocoolers over the range of 77 K to 200 K. Refrigeration at intermediate temperatures is also available. The use of single-component fluids in each of the stages is expected to eliminate the problem of pulsating flow and temperature oscillations experienced in microcryocoolers using mixed refrigerants.

  11. Extreme ultraviolet spectroscopy of low pressure helium microwave driven discharges

    Science.gov (United States)

    Espinho, Susana; Felizardo, Edgar; Tatarova, Elena; Alves, Luis Lemos

    2016-09-01

    Surface wave driven discharges are reliable plasma sources that can produce high levels of vacuum and extreme ultraviolet radiation (VUV and EUV). The richness of the emission spectrum makes this type of discharge a possible alternative source in EUV/VUV radiation assisted applications. However, due to challenging experimental requirements, publications concerning EUV radiation emitted by microwave plasmas are scarce and a deeper understanding of the main mechanisms governing the emission of radiation in this spectral range is required. To this end, the EUV radiation emitted by helium microwave driven plasmas operating at 2.45 GHz has been studied for low pressure conditions. Spectral lines from excited helium atoms and ions were detected via emission spectroscopy in the EUV/VUV regions. Novel data concerning the spectral lines observed in the 23 - 33 nm wavelength range and their intensity behaviour with variation of the discharge operational conditions are presented. The intensity of all the spectral emissions strongly increases with the microwave power delivered to the plasma up to 400 W. Furthermore, the intensity of all the ion spectral emissions in the EUV range decreases by nearly one order of magnitude as the pressure was raised from 0.2 to 0.5 mbar. Work funded by FCT - Fundacao para a Ciencia e a Tecnologia, under Project UID/FIS/50010/2013 and grant SFRH/BD/52412/2013 (PD-F APPLAuSE).

  12. "Politically-Incorrect" Electron Behavior in Low Pressure RF Discharges

    Science.gov (United States)

    Godyak, Valery; Kolobov, Vladimir

    1996-10-01

    The main interaction of plasma electrons with electromagnetic fields for bounded plasma of an rf discharge occurs in the vicinity of its boundaries (in the rf sheath of a capacitive rf discharge and in the skin layer of an inductive one). On the other hand, due to plasma inhomogeneity, a dc ambipolar field is always present in the bounded plasma. in low pressure discharges the ambipolar potential well captures low energy electrons within the discharge center while high energy electrons freely overcome the ambipolar potential and reach the plasma boundaries where heating takes place. Being segregated in space, low energy electrons are discriminated from participation in the heating process. When Coulomb interaction between low and high energy electron groups is weak, their temperatures appear to be essentially different ( a low energy peak on the EEDF). In this presentation we present theoretical and experimental evidence of such an apartheid in the low and high energy electron populations of the EEDF in rf discharge and we outline discharge conditions where such abnormal EEDF behavior is possible.

  13. Absorption spectrum of very low pressure atomic hydrogen

    CERN Document Server

    Moret-Bailly, Jacques

    2015-01-01

    Spectra of quasars result primarily from interactions of natural light with atomic hydrogen. A visible absorption of a sharp and saturated spectral line in a gas requires a low pressure, so a long path without blushing as a cosmological redshift. Burbidge and Karlsson observed that redshifts of quasars result from fundamental redshifts, written 3K and 4K, that cause a shift of absorbed beta and gamma lines of H to alpha gas line. Thus absorbed spectrum is shifted until an absorbed line overlaps with Lyman alpha line of gas: redshift only occurs if an alpha absorption pumps atoms to 2P state. Thus, space is divided into spherical shells centered on the quasar, containing or not 2P atoms. Neglecting collisional de-excitations in absorbing shells, more and more atoms are excited until amplification of a beam having a long path in a shell, thus perpendicular to the observed ray, is large enough for a superradiant flash at alpha frequency. Energy is provided by atoms and observed ray, absorbing a line at local Lym...

  14. Endoscopic PIV measurements in a low pressure turbine rig

    Energy Technology Data Exchange (ETDEWEB)

    Kegalj, Martin; Schiffer, Heinz-Peter [Technische Universitaet Darmstadt (Germany). Department of Gas Turbines and Aerospace Propulsion

    2009-10-15

    Particle-Image-Velocimetry (PIV) is a useful way to acquire information about the flow in turbomachinery. Several premises have to be fulfilled to achieve high-quality data, for example, optical access, low vibrations and low reflections. However, not all test facilities comply with these requirements. If there is no optical access to the test area, measurements cannot be performed. The use of borescopic optics is a possible solution to this issue, as the access required is very small. Several different techniques can be used to measure the three components of the velocity vector, one of which is Stereo-PIV. These techniques require either large optical access from several viewing angles or highly complex setups. Orthogonal light sheet orientations in combination with borescopic optics using Planar-PIV can deliver sufficient information about the flow. This study will show the feasibility of such an approach in an enclosed test area, such as the interblade space in a Low-Pressure-Turbine-Rig. The results from PIV will be compared with data collected with conventional techniques, such as the Five-Hole-Probe and the 2-component Hot-Wire-Anemometry. An analysis of time- and phase-averaged data will be performed. (orig.)

  15. Characteristics of Cylindrical Microwave Plasma Source at Low Pressure

    Science.gov (United States)

    Park, Seungil; Youn, S.; Kim, S. B.; Yoo, S. J.

    2016-10-01

    A microwave plasma source with a cylindrical resonance cavity has been proposed to generate the plasma at low pressure. This plasma source consists of magnetron, waveguide, antenna, and cavity. The microwave generating device is a commercial magnetron with 1 kW output power at the frequency of 2.45 GHz. The microwave is transmitted through the rectangular waveguide with the whistle shape, and coupled to the cavity by the slot antenna. The resonant mode of the cylindrical cavity is the TE111 mode. The operating pressure is between 0.1 Torr and 0.3 Torr with the Argon and nitrogen gas. The electron temperature and electron number density of argon plasma were measured with the optical emission spectroscopy measurement. And Ar1s5 metastable density was measured using tunable diode laser absorption spectroscopy (TDLAS). The plasma diagnostic results of a cylindrical microwave plasma source would be described in this study. This work was supported by R&D Program of ``Plasma Advanced Technology for Agriculture and Food (Plasma Farming)'' through the National Fusion Research Institute of Korea (NFRI) funded by the Government funds.

  16. Longitudinal discharge pumped low-pressure XeCl laser

    Science.gov (United States)

    Fedorov, A. I.

    2013-10-01

    We have studied output parameters of a XeCl and a N2 laser pumped by a longitudinal discharge with automatic spark UV preionisation. The output parameters of a low-pressure (30 Torr) XeCl laser operating with Ar, Ne and He as buffer gases or with no buffer gas have been optimised for the first time. The laser generated 5-ns FWHM pulses with an average power of 0.5 mW and output energy of 0.15 mJ. Under longitudinal discharge pumping, an output energy per unit volume of 1.8 J L-1 atm-1 was reached using helium as a buffer gas. With argon-containing and buffer-free mixtures, it was 1.5 J L-1 atm-1. The N2 laser generated 2.5-ns FWHM pulses with an average power of 0.35 mW and output energy of 0.05 mJ.

  17. Carotid angioplasty and stenting in the elderly

    Energy Technology Data Exchange (ETDEWEB)

    Kadkhodayan, Yasha [Washington University School of Medicine, Interventional Neuroradiology, Mallinckrodt Institute of Radiology, St. Louis, MO (United States); Cross, DeWitte T.; Moran, Christopher J. [Washington University School of Medicine, Interventional Neuroradiology, Mallinckrodt Institute of Radiology, St. Louis, MO (United States); Washington University School of Medicine, Department of Neurological Surgery, St. Louis, MO (United States); Derdeyn, Colin P. [Washington University School of Medicine, Interventional Neuroradiology, Mallinckrodt Institute of Radiology, St. Louis, MO (United States); Washington University School of Medicine, Department of Neurological Surgery, St. Louis, MO (United States); Washington University School of Medicine, Department of Neurology, St. Louis, MO (United States)

    2007-11-15

    To investigate the technical success rate as well as the procedural and mid-term complication rates of carotid angioplasty and stenting in elderly patients, a group excluded from large randomized endarterectomy trials given their perceived high surgical risk. Of 200 consecutive carotid angioplasty and/or stenting procedures performed between March 1996 and March 2005, 21 procedures were performed without cerebral protection devices in 20 patients over the age of 79 years (mean age: 83 years, 12 men, eight women). These patients' medical records were retrospectively reviewed for vascular imaging reports and available clinical follow-up. Procedural and mid-term complication rates were calculated and compared to a previously published cohort of 133 consecutive patients {<=}79 years of age who also underwent endovascular treatment at our institution. Carotid stenosis was reduced from a mean of 82% to no significant stenosis in all procedures. The procedural stroke rate was zero of 21 procedures. The procedural transient ischemic attack rate (TIA) was one of 21 procedures (4.8%). Mean follow-up was 24.6 months (range: 1.0-79.5 months) with at least a 30-day follow-up for 20 of the 21 procedures (95.2%). There were no new strokes. There was one recurrent ipsilateral TIA at 1.9 months. In five cases with follow-up carotid ultrasonography, no hemodynamically significant restenosis had occurred. There were three myocardial infarctions (MI) occurring at 0.5, 2.1, and 15.2 months, of which the last MI was fatal. The composite 30-day stroke and death rate was zero of 21 procedures (95% confidence interval: 0-14%). No significant difference was found in the 30-day rate of stroke, TIA, MI, or death between the elderly and younger patients. Carotid angioplasty and stenting in elderly patients can be performed successfully with acceptable procedural and mid-term complication rates comparable to younger patients. (orig.)

  18. Percutaneous transluminal coronary angioplasty for culprit lesions in patients with post myocardial infarction angina based on dextrocardia and anomalous coronary arteries. Case reports and methods.

    Science.gov (United States)

    Yabe, Y; Tsukahara, R

    1995-05-01

    Four cases of successful coronary angioplasty for anomalous coronary arteries, including dextrocardia associated with three-vessel disease, single left coronary artery with proximal left anterior descending lesion, anomalous right coronary artery (RCA) from adjacent left coronary sinus of Valsalva associated with proximal RCA lesion, and anomalous left circumflex angulated lesion bifurcated from the RCA, were encountered. Four cases with 8 target lesions who had a mean age of 63.5 +/- 11.5 years old are presented. All the targets lesions were completely dilated through balloon angioplasty, including use of a newly developed support device for cases with large jeopardized myocardium. The factors for complete revascularization were appropriate selection of catheters and originality and ingenuity of procedural technique based on the anatomic characteristics.

  19. Primary coronary angioplasty in a nonagenarian

    Directory of Open Access Journals (Sweden)

    Baracioli Luciano M.

    2002-01-01

    Full Text Available A woman aged 98 years entered the tertiary hospital service with a picture of acute myocardial infarction of the extensive anterior wall, which began 4 hours earlier. Due to the large myocardial risk area suggested by the electrocardiogram, the patient was taken to the hemodynamics laboratory for the performance of emergency coronary arteriography, which revealed occlusion in the proximal third of the anterior descending artery. Primary angioplasty followed by stent grafting was successfully performed. The patient had a satisfactory evolution (Killip I and was discharged from the hospital on the seventh postinfarction day. We discuss here aspects of thrombolysis and coronary percutaneous interventions in the aged.

  20. Characteristics of smooth muscle cells' shape and proliferation rate in novel short-term thermal angioplasty ex vivo and in vitro.

    Science.gov (United States)

    Kunio, Mie; Shimazaki, Natsumi; Ito, Arisa; Hayashi, Tomoaki; Arai, Tsunenori

    2010-01-01

    We investigated the influences on the smooth muscle cells of temporally heated arterial walls in both ex vivo and in vitro study to determine the optimum heat parameter of novel short-term thermal angioplasty, Photo-thermo Dynamic Balloon Angioplasty (PTDBA). Arterial heating dilatation was performed by the prototype PTDBA balloon ex vivo. We found that the smooth muscle cells in the vessel wall were stretch-fixed after the heating dilatation ex vivo. The stretch-fixing rate of these cells was increased with the temperature rise in the balloon of PTDBA from 60 °C to 70 °C. We measured the proliferation rate of the stretch-fixed smooth muscle cells, which were extracted from porcine arteries, on specially designed culture equipment in vitro. It was observed that the proliferation rate was inhibited at 20 % stretching compared to 10 % stretching. We think the stretch-fixing of the smooth muscle cells might not be harmful for PTDBA performances.

  1. Onset of Nucleate Boiling in Rectangular Channels under Low Pressure

    Energy Technology Data Exchange (ETDEWEB)

    Song, Jung Hyun; Lee, Juhyung; Jeong, Yong Hoon [Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of); Chang, Soon Heung [Handong University, Pohang (Korea, Republic of)

    2015-10-15

    In this study, new methodology to define ONB point based on the heat transfer coefficient difference between single phase heat transfer and two phase heat transfer using single phase heat transfer correlation. In addition, several existing ONB prediction correlations based on the Hsu's model showed large error with experimental data. It can support that not only heat flux and wall superheat, but also the local parameters should be figured into ONB prediction. Nuclear reactors can be divided into two types; commercial reactor and research reactor. Radiation from research reactors is used for many industries. Due to that characteristic of research reactors, as many people work around research reactor, the design with conservative safety margin for research reactor is more sensitive issue. Some research reactors such as the Jordan Research and Training Reactor (JRTR) have three characteristics. First, they operate under atmospheric pressure. Second, they use the nuclear fuel plate. Third, they use downward flow to remove the heat of the fuel plate. However, one of the precautions of using downward flow under low pressure is that fluid behavior can change much faster than under high pressure. Bubble nucleation itself is not important for nuclear reactor safety at all, but it can be lead to critical thermal-hydraulic events such as onset of fluid instability (OFI) or critical heat flux (CHF) easily. Also, bubble nucleation would be avoided to maintain the steady normal operation. The IAEA also recommends for research reactors to have enough ONB margin to maintain a normal operation state in 'IAEA-TECDOC-233' (1980). It can support that the existing ONB prediction correlations are not suitable for predict ONB in rectangular channel and new correlation is needed to this condition.

  2. Studies of Methane Counterflow Flames at Low Pressures

    Science.gov (United States)

    Burrell, Robert Roe

    Methane is the smallest hydrocarbon molecule, the fuel most widely studied in fundamental flame structure studies, and a major component of natural gas. Despite many decades of research into the fundamental chemical kinetics involved in methane oxidation, ongoing advancements in research suggest that more progress can be made. Though practical combustors of industrial and commercial significance operate at high pressures and turbulent flow conditions, fundamental understanding of combustion chemistry in flames is more readily obtained for low pressure and laminar flow conditions. Measurements were performed from 1 to 0.1 atmospheres for premixed methane/air and non-premixed methane-nitrogen/oxygen flames in a counterflow. Comparative modeling with quasi-one-dimensional strained flame codes revealed bias-induced errors in measured velocities up to 8% at 0.1 atmospheres due to tracer particle phase velocity slip in the low density gas reacting flow. To address this, a numerically-assisted correction scheme consisting of direct simulation of the particle phase dynamics in counterflow was implemented. Addition of reactions describing the prompt dissociation of formyl radicals to an otherwise unmodified USC Mech II kinetic model was found to enhance computed flame reactivity and substantially improve the predictive capability of computed results for measurements at the lowest pressures studied. Yet, the same modifications lead to overprediction of flame data at 1 atmosphere where results from the unmodified USC Mech II kinetic mechanism agreed well with ambient pressure flame data. The apparent failure of a single kinetic model to capture pressure dependence in methane flames motivates continued skepticism regarding the current understanding of pressure dependence in kinetic models, even for the simplest fuels.

  3. Obesity and gastric balloon

    Directory of Open Access Journals (Sweden)

    Mohammed I Yasawy

    2014-01-01

    Full Text Available Background: The obesity epidemic, which is among the most common nutritional disorders, is rising rapidly worldwide. It leads to several health problems such as metabolic disorders, stroke, and even cancer. Efforts to control obesity with exercise and diet have a limited value in obese patients and different approaches to do this have been tried. In this paper, we share our experience with bioenteric intragastric balloon (BIB in treating obesity: Its safety, tolerability, and its efficacy in weight reduction. Materials and Methods: From January 2009 to September 2012, a total of 190 gastric balloons was inserted on patients at the endoscopy unit in King Fahd Hospital of the University, Al-Khobar. This is an evaluation of the first 100 patients. All the patients had a body mass index of over 30 kg/m 2 and were within the age range of 17-55 with a mean age of 32 years. After consent, preballoon investigation tests and anesthesia evaluation, BIB was inserted under monitored anesthesia care sedation in the endoscopy suite. The balloon was filled with 500-700 mls of stained saline. All patients′ were given an analgesic and antiemetic for a week and antisecretory proton pump inhibitor′s for 6 months. Diet and the importance of the exercise were part of the preballoon insertion phase and protocol. The balloon was removed after 6-12 months. Results: The weight loss response to BIB in the 100 patients are classified into four groups: In the uncooperative, noncompliant patients - the maximum weight loss was 7 kg, while in the most compliant patients the weight loss reached up to 39 kg. In addition, there was significant improvement into diabetes mellitus, hypertension, dyslipidemia, and fatty liveras. Its safety and tolerability were extremely acceptable. Conclusion: Our data indicates that in well-selected patients, BIB is an effective device, which with minimum complications helps to achieve body weight loss and resolve many obesity related

  4. NASA Super Pressure Balloon

    Science.gov (United States)

    Fairbrother, Debbie

    2017-01-01

    NASA is in the process of qualifying the mid-size Super Pressure Balloon (SPB) to provide constant density altitude flight for science investigations at polar and mid-latitudes. The status of the development of the 18.8 million cubic foot SPB capable of carrying one-tone of science to 110,000 feet, will be given. In addition, the operating considerations such as launch sites, flight safety considerations, and recovery will be discussed.

  5. Space Weather Ballooning

    Science.gov (United States)

    Phillips, Tony; Johnson, Sam; Koske-Phillips, Amelia; White, Michael; Yarborough, Amelia; Lamb, Aaron; Herbst, Anna; Molina, Ferris; Gilpin, Justin; Grah, Olivia; Perez, Ginger; Reid, Carson; Harvey, Joey; Schultz, Jamie

    2016-10-01

    We have developed a "Space Weather Buoy" for measuring upper atmospheric radiation from cosmic rays and solar storms. The Buoy, which is carried to the stratosphere by helium balloons, is relatively inexpensive and uses off-the-shelf technology accessible to small colleges and high schools. Using this device, we have measured two Forbush Decreases and a small surge in atmospheric radiation during the St. Patrick's Day geomagnetic storm of March 2015.

  6. Outpatient coronary angioplasty: feasible and safe.

    Science.gov (United States)

    Slagboom, Ton; Kiemeneij, Ferdinand; Laarman, Gert Jan; van der Wieken, Ron

    2005-04-01

    This study tested the safety and feasibility of coronary angioplasty on an outpatient basis. The purpose of this approach includes cost-effectiveness and patient comfort. Six hundred forty-four patients were randomized to either transradial or transfemoral PTCA using 6 Fr equipment. Patients were triaged to outpatient management based on a predefined set of predictors of an adverse outcome in the first 24 hr after initially successful coronary angioplasty. Three hundred seventy-five patients (58%) were discharged 4-6 hr after PTCA; 42% stayed in hospital overnight. In the outpatient group, one adverse event occurred (subacute stent thrombosis 7 hr postdischarge, nonfatal myocardial infarction). There were no major vascular complications. In the hospital group, 19 patients (7%) sustained an adverse cardiac even in the first 24 hr; 1 patient died. Patients treated via the femoral route had more (minor) bleeding complications (19 patients; 6%); in 17 of these, this was the sole reason that discharge was delayed. PTCA on an outpatient basis, performed via the radial or the femoral artery with low-profile equipment, is safe and feasible in a considerable part of a routine PTCA population. A larger proportion of transradial patients can be discharged due to a reduction in (minor) bleeding complications.

  7. Prevention of Intracranial In-stent Restenoses: Predilatation with a Drug Eluting Balloon, Followed by the Deployment of a Self-Expanding Stent

    Energy Technology Data Exchange (ETDEWEB)

    Vajda, Zsolt, E-mail: Z.Vajda@klinikum-stuttgart.de; Guethe, Thomas, E-mail: T.Guethe@klinikum-stuttgart.de; Perez, Marta Aguilar, E-mail: M.Aguilar@klinikum-stuttgart.de; Kurre, Wiebke, E-mail: w.kurre@klinikum-stuttgart.de [Klinikum Stuttgart, Katharinenhospital, Klinik fuer Neuroradiologie, Neurozentrum (Germany); Schmid, Elisabeth, E-mail: ESchmid@klinikum-stuttgart.de; Baezner, Hansjoerg, E-mail: H.Baezner@klinikum-stuttgart.de [Klinikum Stuttgart, Klinik fuer Neurologie, Neurozentrum (Germany); Henkes, Hans, E-mail: hhhenkes@aol.com [Klinikum Stuttgart, Katharinenhospital, Klinik fuer Neuroradiologie, Neurozentrum (Germany)

    2013-04-15

    Stenting in intracranial atherosclerotic disease (ICAD) is increasingly debated, due to issues of procedural safety, technical efficacy, and in-stent recurrent stenoses (ISR). In the present study, feasibility, safety, and efficacy of angioplasty using a drug-eluting balloon (DEB) followed by the implantation of a self-expanding stent (Enterprise) were evaluated for the treatment of ICAD lesions. Fifty-two patients (median age: 71 years; range: 54-86 years; male/female ratio 37:15) underwent stenting of high-grade ICAD lesions between February 2010 and November 2011 in a single center. Angioplasty using a paclitaxel coated SeQuent Please (B. Braun, Germany) or DIOR (Eurocor, Germany) coronary PTCA balloon, followed by the implantation of a self-expanding stent (Enterprise, Codman, USA) was performed in 54 lesions. Angiographic and clinical follow-up was performed at 6 and 12 weeks, 6 and 12 months, and yearly thereafter. Technical success rate, periprocedural complications, occurrence of recurrent ischemic symptoms, and the development of an ISR were analyzed. Angioplasty using a DEB followed by stent implantation was successfully performed in 44 (81 %) cases. DEB insertion failed in 19 % of the cases and angioplasty was finally performed using a conventional PTCA balloon. The combined procedure related permanent neurologic morbidity and mortality rate (stroke, ICH, and subarachnoid hemorrhage) at 30 days and beyond was 5 %. Angiographic and clinical follow-up were obtained in 33 (61 %) lesions in 32 patients. Recurrent stenosis was seen in one (3 %) lesion. Angioplasty and stenting using a DEB is safe and yields encouragingly low ISR rates. Further technical developments to improve lesion accessibility are, nevertheless, mandatory.

  8. Breakthrough in Mars balloon technology

    Science.gov (United States)

    Kerzhanovich, V. V.; Cutts, J. A.; Cooper, H. W.; Hall, J. L.; McDonald, B. A.; Pauken, M. T.; White, C. V.; Yavrouian, A. H.; Castano, A.; Cathey, H. M.; Fairbrother, D. A.; Smith, I. S.; Shreves, C. M.; Lachenmeier, T.; Rainwater, E.; Smith, M.

    2004-01-01

    Two prototypes of Mars superpressure balloons were flight tested for aerial deployment and inflation in the Earth's stratosphere in June, 2002. One was an 11.3 m diameter by 6.8 m high pumpkin balloon constructed from polyethylene film and Zylon (PBO) tendons, the second was a 10 m diameter spherical balloon constructed from 12 μm thick Mylar film. Aerial deployment and inflation occurred under parachute descent at 34 km altitude, mimicing the dynamic pressure environment expected during an actual Mars balloon mission. Two on-board video cameras were used on each flight to provide real-time upward and downward views of the flight train. Atmospheric pressure and temperature were also recorded. Both prototypes successfully deployed from their storage container during parachute descent at approximately 40 m/s. The pumpkin balloon also successfully inflated with a 440 g charge of helium gas injected over a 1.5-min period. Since the helium inflation system was deliberately retained after inflation in this test, the pumpkin balloon continued to fall to the ocean where it was recovered for post-flight analysis. The less robust spherical balloon achieved only a partial (~70%) inflation before a structural failure occurred in the balloon film resulting in the loss of the vehicle. This structural failure was diagnosed to result from the vigorous oscillatory motion of the partially inflated balloon, possibly compounded by contact between the balloon film and an instrumentation box above it on the flight train. These two flights together represent significant progress in the development of Mars superpressure balloon technology and pave the way for future flight tests that will include post-deployment flight of the prototype balloons at a stable altitude.

  9. Cleft formation in pumpkin balloons

    Science.gov (United States)

    Baginski, Frank E.; Brakke, Kenneth A.; Schur, Willi W.

    NASA’s development of a large payload, high altitude, long duration balloon, the Ultra Long Duration Balloon, centers on a pumpkin shape super-pressure design. Under certain circumstances, it has been observed that a pumpkin balloon may be unable to pressurize into the desired cyclically symmetric equilibrium configuration, settling into a distorted, undesired state instead. Success of the pumpkin balloon for NASA requires a thorough understanding of the phenomenon of multiple stable equilibria and developing of means for the quantitative assessment of design measures that prevent the occurrence of undesired equilibrium. In this paper, we will use the concept of stability to classify cyclically symmetric equilibrium states at full inflation and pressurization. Our mathematical model for a strained equilibrium balloon, when applied to a shape that mimics the Phase IV-A balloon of Flight 517, predicts instability at float. Launched in Spring 2003, this pumpkin balloon failed to deploy properly. Observations on pumpkin shape type super-pressure balloons that date back to the 1980s suggest that within a narrowly defined design class of pumpkin shape super-pressure balloons where individual designs are fully described by the number of gores ng and by a single measure of the bulging gore shape, the designs tend to become more vulnerable with the growing number of gores and with the diminishing size of the bulge radius rB Weight efficiency considerations favor a small bulge radius, while robust deployment into the desired cyclically symmetrical configuration becomes more likely with an increased bulge radius. In an effort to quantify this dependency, we will explore the stability of a family of balloon shapes parametrized by (ng, rB) which includes a design that is very similar, but not identical, to the balloon of Flight 517. In addition, we carry out a number of simulations that demonstrate other aspects related to multiple equilibria of pumpkin balloons.

  10. Treatment of pacemaker-induced superior vena cava syndrome by balloon angioplasty and stenting.

    LENUS (Irish Health Repository)

    Klop, B

    2011-01-01

    Superior vena cava (SVC) syndrome is a rare but serious complication after pacemaker implantation. This report describes three cases of SVC syndrome treated with venoplasty and venous stenting, with an average follow-up of 30.7 (±3.1) months. These cases illustrate that the definitive diagnosis, and the extent and location of venous obstruction, can only be determined by venography.

  11. Comparative quantitative angiographic analysis of directional coronary atherectomy and balloon coronary angioplasty

    NARCIS (Netherlands)

    A.W.M. Umans (A. W M); K.J. Beatt (Kevin); B.J.W.M. Rensing (Benno); W.R.M. Hermans (Walter); P.J. de Feyter (Pim); P.W.J.C. Serruys (Patrick)

    1991-01-01

    markdownabstract__Abstract__ An attempt to assess the “utility” of directional atherectomy was made using a new quantitative angiographic index. This index can be subdivided into an initial gain component and a restenosis component. The initial gain index is the ratio between the gain in diameter d

  12. Balloon Angioplasty and Drug Eluting Stenting for Treatment of Peripheral Arterial Occlusive Disease

    Directory of Open Access Journals (Sweden)

    Akın İzgi

    2010-08-01

    Full Text Available Peripheral arterial disease is one of the manifestations of systemic atherosclerosis. In the last decade, remarkable technological advances, especially in the stent area, have shifted revascularization strategies from traditional open surgical approaches toward less morbide percutaneous endovascular treatments. However, even with new designed nitinol bare stents, restenosis remains as the major obstacle of this procedures. More recently, drug eluting stent platforms have been used to treat atherosclerotic peripheral arterial disease. In this article, we reviewed new studies relevant to drug eluting stents for lower extremity peripheral arterial occlusive disease.

  13. [Reintervention with percutaneous balloon angioplasty in patients with congenital heart disease with left-sided obstructions].

    Science.gov (United States)

    Márquez-González, Horacio; López-Gallegos, Diana; Pérez-Velázquez, Nataly Alejandra; Yáñez-Gutiérrez, Lucelli

    2017-01-01

    Introducción: las obstrucciones izquierdas representan 15% de las cardiopatías congénitas (CC). El tratamiento en la edad adulta es quirúrgico; no obstante, la dilatación con balón puede paliar los síntomas en edad pediátrica para permitir que alcancen la talla diana. El objetivo fue determinar la sobrevida y los factores asociados a la reintervención en enfermos con CC con obstrucción izquierda tratados con plastía con balón. Métodos: se realizó un estudio de cohorte en pacientes entre 4 y 17 años con cardiopatías de obstrucción izquierda (estenosis valvular, supravalvular y coartación aórtica) tratados con angioplastía con balón exitosa. El seguimiento fue de 10 años y la variable de desenlace fue la reestenosis con criterios para reintervención. Se consideraron variables pronósticas la etapa pediátrica al momento del procedimiento, el estado nutricional, el gradiente residual y la presencia de síndromes genéticos. Se usaron medidas de tendencia central y dispersión. Se usó chi cuadrada en variables cualitativas y Kruskal-Wallis en variables cuantitativas. Resultados: fueron 110 pacientes; 40% presentó coartación aórtica, 35% estenosis valvular y 25% estenosis supravalvular aórtica. El 39% requirió reintervención y la frecuencia fue la siguiente: 80% en estenosis supravalvular, 35% en coartación aórtica y 14% en estenosis valvular aórtica. Conclusión: la intervención con balón es una medida paliativa que permite a los enfermos con obstrucciones izquierdas alcanzar la talla diana.

  14. Magnetic Particle / Magnetic Resonance Imaging: In-Vitro MPI-Guided Real Time Catheter Tracking and 4D Angioplasty Using a Road Map and Blood Pool Tracer Approach.

    Directory of Open Access Journals (Sweden)

    Johannes Salamon

    Full Text Available In-vitro evaluation of the feasibility of 4D real time tracking of endovascular devices and stenosis treatment with a magnetic particle imaging (MPI / magnetic resonance imaging (MRI road map approach and an MPI-guided approach using a blood pool tracer.A guide wire and angioplasty-catheter were labeled with a thin layer of magnetic lacquer. For real time MPI a custom made software framework was developed. A stenotic vessel phantom filled with saline or superparamagnetic iron oxide nanoparticles (MM4 was equipped with bimodal fiducial markers for co-registration in preclinical 7T MRI and MPI. In-vitro angioplasty was performed inflating the balloon with saline or MM4. MPI data were acquired using a field of view of 37.3×37.3×18.6 mm3 and a frame rate of 46 volumes/sec. Analysis of the magnetic lacquer-marks on the devices were performed with electron microscopy, atomic absorption spectrometry and micro-computed tomography.Magnetic marks allowed for MPI/MRI guidance of interventional devices. Bimodal fiducial markers enable MPI/MRI image fusion for MRI based roadmapping. MRI roadmapping and the blood pool tracer approach facilitate MPI real time monitoring of in-vitro angioplasty. Successful angioplasty was verified with MPI and MRI. Magnetic marks consist of micrometer sized ferromagnetic plates mainly composed of iron and iron oxide.4D real time MP imaging, tracking and guiding of endovascular instruments and in-vitro angioplasty is feasible. In addition to an approach that requires a blood pool tracer, MRI based roadmapping might emerge as a promising tool for radiation free 4D MPI-guided interventions.

  15. Titan Balloon Convection Model Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This innovative research effort is directed at determining, quantitatively, the convective heat transfer coefficients applicable to a Montgolfiere balloon operating...

  16. Application of new balloon catheters in the treatment of congenital heart defects

    Science.gov (United States)

    Fiszer, Roland; Szkutnik, Małgorzata; Smerdziński, Sebastian; Chodór, Beata; Białkowski, Jacek

    2016-01-01

    Introduction Balloon angioplasty (BAP) and aortic or pulmonary balloon valvuloplasty (BAV, BPV) are well-established treatment options in congenital heart defects. Recently, significant technological progress has been made and new catheters have been implemented in clinical practice. Aim To analyze the results of BAP, BAV and BPV with the new balloon catheter Valver and its second generation Valver II, which the company Balton (Poland) launched and developed. These catheters have not been clinically evaluated yet. Material and methods We performed 64 interventions with Valver I and Valver II. With Valver I the following procedures were performed: 17 BPV (including 9 in tetralogy of Fallot – TOF), 10 BAV and 27 BAP in coarctations of the aorta (CoA) – including 9 native and 18 after surgery. With Valver II ten interventions were done – 3 BPV, 2 pulmonary supravalvular BAP (after switch operations), 2 BAP of recoarctations and 3 other BAP. Age of the patients ranged from a few days to 40 years. Results All procedures were completed successfully, without rupture of any balloon catheters. The pressure gradient drop was statistically significant in all groups: BPV in isolated pulmonary valvular stenosis 28.1 mm Hg (mean), BPV in TOF 18.7 mm Hg, BAV 32.8 mm Hg, BAP in native CoA 15.4 mm Hg and in recoarctations 18.6 mm Hg. In 3 cases during rapid deflation of Valver I, wrinkles of the balloons made it impossible to insert the whole balloon into the vascular sheath (all were removed surgically from the groin). No such complication occured with Valver II. Conclusions Valver balloon catheters are an effective treatment modality in different valvular and vascular stenoses. PMID:27625686

  17. Percutaneous transluminal angioplasty of infrarenal arteries in intermittent claudication

    DEFF Research Database (Denmark)

    Henriksen, L O; Jørgensen, B; Holstein, P E;

    1988-01-01

    Percutaneous transluminal angioplasty was performed on 55 iliac and 31 femoropopliteal arteries in 71 patients with intermittent claudication (23 women, 48 men). The two-year patency rate was 80% after iliac and 41% after femoropopliteal angioplasty. In 17 femoropopliteal cases with lesions greater...... than or equal to 5 cm the 2-year patency rate was only 32%, but the corresponding figure for shorter lesions was 53%. Complicating haematoma appeared in 10% of the cases and the arterial state deteriorated in one patient. There was no distal embolization. Percutaneous transluminal angioplasty...

  18. Clopidogrel Responsiveness in Patients Undergoing Peripheral Angioplasty

    Energy Technology Data Exchange (ETDEWEB)

    Pastromas, Georgios, E-mail: geopastromas@gmail.com; Spiliopoulos, Stavros, E-mail: stavspiliop@upatras.gr; Katsanos, Konstantinos, E-mail: katsanos@med.upatras.gr; Diamantopoulos, Athanasios, E-mail: adiamantopoulos@gmail.com; Kitrou, Panagiotis, E-mail: panoskitrou@gmail.com; Karnabatidis, Dimitrios, E-mail: karnaby@med.upatras.gr; Siablis, Dimitrios, E-mail: siablis@med.upatras.gr [Patras University Hospital, Department of Interventional Radiology (Greece)

    2013-12-15

    Purpose: To investigate the incidence and clinical significance of platelet responsiveness in patients receiving clopidogrel after peripheral angioplasty procedures. Materials and Methods: This prospective study included patients receiving antiplatelet therapy with clopidogrel 75 mg after infrainguinal angioplasty or stenting and who presented to our department during routine follow-up. Clopidogrel responsiveness was tested using the VerifyNow P2Y12 Assay. Patients with residual platelet reactivity units (PRU) {>=} 235 were considered as nonresponders (NR group NR), whereas patients with PRU < 235 were considered as normal (responders [group R]). Primary end points were incidence of resistance to clopidogrel and target limb reintervention (TLR)-free survival, whereas secondary end points included limb salvage rates and the identification of any independent predictors influencing clinical outcomes. Results: In total, 113 consecutive patients (mean age 69 {+-} 8 years) with 139 limbs were enrolled. After clopidogrel responsiveness analysis, 61 patients (53.9 %) with 73 limbs (52.5 %) were assigned to group R and 52 patients (46.1 %) with 66 limbs (47.5 %) to group NR. Mean follow-up interval was 27.7 {+-} 22.9 months (range 3-95). Diabetes mellitus, critical limb ischemia, and renal disease were associated with clopidogrel resistance (Fisher's exact test; p < 0.05). According to Kaplan-Meier analysis, TLR-free survival was significantly superior in group R compared with group NR (20.7 vs. 1.9 %, respectively, at 7-year follow-up; p = 0.001), whereas resistance to clopidogrel was identified as the only independent predictor of decreased TLR-free survival (hazard rate 0.536, 95 % confidence interval 0.31-0.90; p = 0.01). Cumulative TLR rate was significantly increased in group NR compared with group R (71.2 % [52 of 73] vs. 31.8 % [21 of 66], respectively; p < 0.001). Limb salvage was similar in both groups. Conclusion: Clopidogrel resistance was related with

  19. Use of the AngioSculpt scoring balloon for infrapopliteal lesions in patients with critical limb ischemia: 1-year outcome.

    Science.gov (United States)

    Bosiers, Marc; Deloose, Koen; Cagiannos, Catherine; Verbist, Jürgen; Peeters, Patrick

    2009-01-01

    The AngioSculpt Scoring Balloon Catheter (AngioScore, Inc., Fremont, CA) is composed of a semicompliant balloon encircled by three nitinol spiral struts providing targeted lesion scoring on balloon inflation. Between April 2005 and April 2006, procedural and follow-up data on 31 patients (mean age 76 years; 54.8% males) endovascularly treated for severe infrapopliteal disease were collected. The AngioSculpt catheter was used to treat 36 complex, tibioperoneal, atherosclerotic lesions. All patients had symptomatic critical limb ischemia (Rutherford 4-5) and single-vessel runoff to the ankle. Complication-free survival at 1 month was the safety end point, whereas primary patency and limb salvage were the efficacy end points evaluated at 1 year. The AngioSculpt balloon was successfully inflated in all 36 target lesions. Eleven patients (35.5%) required additional stenting for minor dissections or suboptimal stenosis reduction. The 1-month complication-free survival was 96.8%. One-year survival, primary patency, and limb salvage rates were 83.9 +/- 6.6%, 61.0 +/- 9.3%, and 86.3 +/- 6.4%, respectively. The 1-year data show the AngioSculpt Scoring Balloon Catheter to be an effective and safe treatment for infrapopliteal, atherosclerotic lesions in patients with critical limb ischemia. However, more patients, a longer follow-up, and randomized studies comparing it with conventional balloon angioplasty and stenting in the infrapopliteal region are required.

  20. Buddy balloon for TAVI.

    Science.gov (United States)

    Balkin, Jonathan; Silberman, Shuli; Almagor, Yaron

    2013-11-15

    Percutaneous transfemoral aortic valve replacement is a new rapidly evolving technique that has made significant progress in recent years. The technology is however limitted and in some cases has resulted in failure to deliver the prosthetic valve. We describe a new technique using a buddy balloon, from the contralateral femoral artery, to assist in crossing the native aortic valve in those cases where extreme calcification and or tortuosity have caused the delivery system to hang up on the aortic wall. The technique is easily applied and facilitates the success of the procedure in cases which may otherwise have to be converted to open surgical aortic valve replacement.

  1. A Methane Balloon Inflation Chamber

    Science.gov (United States)

    Czerwinski, Curtis J.; Cordes, Tanya J.; Franek, Joe

    2005-01-01

    The various equipments, procedure and hazards in constructing the device for inflating a methane balloon using a standard methane outlet in a laboratory are described. This device is fast, safe, inexpensive, and easy to use as compared to a hydrogen gas cylinder for inflating balloons.

  2. Surgical Space Conditions During Low-Pressure Laparoscopic Cholecystectomy with Deep Versus Moderate Neuromuscular Blockade

    DEFF Research Database (Denmark)

    Staehr-Rye, Anne K; Rasmussen, Lars S.; Rosenberg, Jacob;

    2014-01-01

    described, but deep neuromuscular blockade may be beneficial. We investigated if deep muscle relaxation would be associated with a higher proportion of procedures with "optimal" surgical space conditions compared with moderate relaxation during low-pressure (8 mm Hg) laparoscopic cholecystectomy. METHODS...... with surgical space conditions that were marginally better than with moderate muscle relaxation during low-pressure laparoscopic cholecystectomy....

  3. Internal ballistics of recoilless high-low pressure guns using hepta-tubular powders

    Directory of Open Access Journals (Sweden)

    M. C. Gupta

    1960-04-01

    Full Text Available In this paper, the theory of recoilless high-low pressure guns has been discussed by taking the form function and the results have been applied to the case of hepta-tubular powders. The results for high-low pressure guns follow as a particular case.

  4. 49 CFR 192.623 - Maximum and minimum allowable operating pressure; Low-pressure distribution systems.

    Science.gov (United States)

    2010-10-01

    ... distribution systems. (a) No person may operate a low-pressure distribution system at a pressure high enough to...) No person may operate a low pressure distribution system at a pressure lower than the minimum... 49 Transportation 3 2010-10-01 2010-10-01 false Maximum and minimum allowable operating...

  5. Nationwide Eclipse Ballooning Project

    Science.gov (United States)

    Colman Des Jardins, Angela; Berk Knighton, W.; Larimer, Randal; Mayer-Gawlik, Shane; Fowler, Jennifer; Harmon, Christina; Koehler, Christopher; Guzik, Gregory; Flaten, James; Nolby, Caitlin; Granger, Douglas; Stewart, Michael

    2016-05-01

    The purpose of the Nationwide Eclipse Ballooning Project is to make the most of the 2017 rare eclipse event in four main areas: public engagement, workforce development, partnership development, and science. The Project is focused on two efforts, both student-led: online live video of the eclipse from the edge of space and the study of the atmospheric response to the eclipse. These efforts, however, involving more than 60 teams across the US, are challenging in many ways. Therefore, the Project is leveraging the NASA Space Grant and NOAA atmospheric science communities to make it a success. The first and primary topic of this poster is the NASA Space Grant supported online live video effort. College and high school students on 48 teams from 31 states will conduct high altitude balloon flights from 15-20 locations across the 8/21/2017 total eclipse path, sending live video and images from near space to a national website. Video and images of a total solar eclipse from near space are fascinating and rare. It’s never been done live and certainly not in a network of coverage across a continent. In addition to the live video to the web, these teams are engaged in several other science experiments as secondary payloads. We also briefly highlight the eclipse atmospheric science effort, where about a dozen teams will launch over one hundred radiosondes from across the 2017 path, recording an unprecedented atmospheric data sample. Collected data will include temperature, density, wind, humidity, and ozone measurements.

  6. Percutaneous transluminal coronary angioplasty in refractory unstable angina pectoris: are new devices useful?

    Science.gov (United States)

    Bertaglia, E; Ramondo, A; Cacciavillani, L; Isabella, G; Reimers, B; Marzari, A; Maddalena, F; Chioin, R

    1996-11-15

    This study was undertaken to assess if the introduction of new angioplasty devices (autoperfusion balloon catheters, stent and atherectomy) could ameliorate early and late results of prompt percutaneous transluminal coronary angioplasty (PTCA) in patients with refractory unstable angina. From January 1993 to June 1995, 59 of 278 patients (14 female, 45 male; mean age: 61 +/- 10 years; range: 38-78) admitted to our Coronary Care Unit with the diagnosis of unstable angina had more than one episode of chest pain at rest with dynamic electrocardiographic ST-T changes and without signs of cardiac necrosis while on medical therapy including oxygen, aspirin, heparin, nitroglycerin and either a beta-blocker or a calcium-antagonist. Coronary angiography was performed within 48 h from the last ischemic attack and a culprilesion technically suitable for PTCA was identified. PTCA was performed in 73 lesions. Elective stent implantation was considered for 16 type B or C lesions in 14 patients. The procedure was initially successful in 52/59 patients (88%), uncomplicated unsuccessful in 4/59 (7%) and complicated in 3/59 (5%). Elective stent insertions were all successful (16/16, 100%). All successfully treated patients were followed up for a mean of 12 +/- 7 months (range: 6-27): 2/52 patients (3.8%) suffered from non-transmural myocardial infarction, 14/52 (26.9%) had a recurrence of angina and 2/52 (3.8%), asymptomatic, had a positive stress test. We conclude that prompt PTCA in refractory unstable angina using 1990s 'state of the art' equipment compares favorably to previous study and that stent delivery might become the elective treatment of complex lesions in this subset of patients.

  7. Subintimal angioplasty for femoro-popliteal occlusive disease.

    Science.gov (United States)

    Markose, George; Miller, Fiona N A C; Bolia, Amman

    2010-11-01

    There has been a longstanding debate about the roles of surgical bypass graft, percutaneous transluminal angioplasty, subintimal angioplasty, and conservative management for femoro-popliteal occlusive disease. Subintimal angioplasty was first described in 1987 as a method of performing an endovascular arterial bypass. The subintimal space at the start of the occlusion is entered with a catheter and a wire loop is used to cross the occlusion and reenter the vessel lumen distally. In patients with critical limb ischemia, there is high quality evidence demonstrating that the limb salvage rate and amputation-free survival rates for surgery and endovascular treatment are similar, but surgery is more expensive than angioplasty in the short term. In patients with intermittent claudication, surgical bypass using an autologous saphenous vein graft is currently believed to be the gold standard, but this is increasingly questioned in the light of recent advances in endovascular techniques. Surgical bypass with vein graft offers a 2-year patency of 81%, compared with 67% for a polytetrafluoroethylene (PTFE) graft and at best 67% for subintimal angioplasty. The better patency offered by surgery must be balanced against a higher morbidity and mortality. To conclude, subintimal angioplasty is an extremely valuable technique in the management of critical limb ischemia. Based on the evidence to date, this technique is likely to have an increasing role in the management of intermittent claudication over the coming years, particularly if the risk of general anaesthesia is high or there is no suitable vein.

  8. Seed disinfection effect of atmospheric pressure plasma and low pressure plasma on Rhizoctonia solani.

    Science.gov (United States)

    Nishioka, Terumi; Takai, Yuichiro; Kawaradani, Mitsuo; Okada, Kiyotsugu; Tanimoto, Hideo; Misawa, Tatsuya; Kusakari, Shinichi

    2014-01-01

    Gas plasma generated and applied under two different systems, atmospheric pressure plasma and low pressure plasma, was used to investigate the inactivation efficacy on the seedborne pathogenic fungus, Rhizoctonia solani, which had been artificially introduced to brassicaceous seeds. Treatment with atmospheric plasma for 10 min markedly reduced the R. solani survival rate from 100% to 3% but delayed seed germination. The low pressure plasma treatment reduced the fungal survival rate from 83% to 1.7% after 10 min and the inactivation effect was dependent on the treatment time. The seed germination rate after treatment with the low pressure plasma was not significantly different from that of untreated seeds. The air temperature around the seeds in the low pressure system was lower than that of the atmospheric system. These results suggested that gas plasma treatment under low pressure could be effective in disinfecting the seeds without damaging them.

  9. A breakthrough technique for the removal of a hemodialysis catheter stuck in the central vein: endoluminal balloon dilatation of the stuck catheter.

    Science.gov (United States)

    Hong, Joon Ho

    2011-01-01

    Hemodialysis (HD) catheters can get stuck in the central vein after long-term use and their removal might become difficult especially in patients with fibrosed or occluded central veins. Herein, a breakthrough technique is reported for the easy removal of a stuck HD catheter from the central vein. Attempts were made to remove a tunneled double-lumen HD catheter from the central vein of a 74-year-old woman, only to find that the catheter was stuck. The patient was transferred to the operating room and a skin incision was made in the neck and the subcutaneous portion of the HD catheter was retrieved from the tunnel. Under fluoroscopy, a guide wire was inserted into one lumen of the HD catheter and advanced into the right atrium beyond the catheter tip. A 5 mm × 4 cm balloon angioplasty catheter was then inserted into the HD catheter lumen over the guide wire and advanced into the jugular vein junction of the HD catheter around the thoracic inlet. The balloon was inflated to its maximum dimension and pressure. This endoluminal dilatation of the HD catheter was continued by deflating the balloon and then pushing the angioplasty catheter 4 cm at a time towards the tip of the HD catheter in the right atrium. After a second balloon angioplasty catheter of 6 mm × 4 cm was used to expand the entire segment of the other lumen, the HD catheter was pulled out easily from the central vein without any resistance. The endoluminal balloon dilatation of the HD catheter not only separates the stuck HD catheter from the adherent vein by breaking the adhesions between them, but also expands the vein simultaneously, thus enabling easy removal of the HD catheter.

  10. Lentivirus-mediated RNAi knockdown of the gap junction protein, Cx43, attenuates the development of vascular restenosis following balloon injury.

    Science.gov (United States)

    Han, Xiao-Jian; Chen, Min; Hong, Tao; Zhu, Ling-Yu; He, Dan; Feng, Jiu-Geng; Jiang, Li-Ping

    2015-04-01

    Percutaneous coronary intervention [PCI or percutaneous transluminal coronary angioplasty (PTCA)] has been developed into a mature interventional treatment for atherosclerotic cardiovascular disease. However, the long-term therapeutic effect is compromised by the high incidence of vascular restenosis following angioplasty, and the underlying mechanisms of vascular restenosis have not yet been fully elucidated. In the present study, we investigated the role of the gap junction (GJ) protein, connexin 43 (Cx43), in the development of vascular restenosis. To establish vascular restenosis, rat carotid arteries were subjected to balloon angioplasty injury. At 0, 7, 14 and 2 days following balloon injury, the arteries were removed, and the intimal/medial area of the vessels was measured to evaluate the degree of restenosis. We found that the intimal area gradually increased following balloon injury. Intimal hyperplasia and restenosis were particularly evident at 14 and 28 days after injury. In addition, the mRNA and protein expression of Cx43 was temporarily decreased at 7 days, and subsequently increased at 14 and 28 days following balloon injury, as shown by RT-PCR and western blot analysis. To determine the involvement of Cx43 in vascular restenosis, the lentivirus vector expressing shRNA targeting Cx43, Cx43-RNAi-LV, was used to silence Cx43 in the rat carotid arteries. The knockdown of Cx43 effectively attenuated the development of intimal hyperplasia and vascular restenosis following balloon injury. Thus, our data indicate the vital role of the GJ protein, Cx43, in the development of vascular restenosis, and provide new insight into the pathogenesis of vascular restenosis. Cx43 may prove to be a novel potential pharmacological target for the prevention of vascular restenosis following PCI.

  11. Emergency coronary artery bypass surgery for failed percutaneous coronary angioplasty. A 10-year experience.

    Science.gov (United States)

    Craver, J M; Weintraub, W S; Jones, E L; Guyton, R A; Hatcher, C R

    1992-01-01

    Six hundred ninety-nine patients have required emergency coronary artery bypass after failed elective percutaneous coronary angioplasty during the decade September 1980 through December 1990. This represents 4% of 9860 patients having 12,146 elective percutaneous coronary angioplasty procedures during this interval. Emergency coronary artery bypass was required for acute refractory myocardial ischemia in 82%. Hospital mortality rate for all patients was 3.1%; 3.7% in patients with refractory myocardial ischemia but 0.8% in patients without refractory myocardial ischemia, p = 0.08. Postprocedural Q-wave myocardial infarctions were observed in 21% versus 2.4%, p less than 0.0001, and intra-aortic balloon pumping was required in 19% with versus 0.8% without refractory myocardial ischemia, p less than 0.0001. Multivessel disease, p = 0.004, age older than 65 years, p = 0.005, and refractory myocardial ischemia, p = 0.08, interacted to produce the highest risk of in-hospital death. Follow-up shows that there have been 28 additional late deaths, including 23 of cardiac causes for a 91% survival at 5 years. Freedom from both late death and Q-wave myocardial infarction at 5 years was 61%. In the group going to emergency coronary artery bypass with refractory myocardial ischemia, the late cardiac survival was 90%, and in those without ischemia, 92% at 5 years, p = not significant. The MI--free survival in the group with refractory ischemia, however, was 56% versus 83% in the group without ischemia, p less than 0.0001. Multivariate analysis showed the highest late event rates for patients with Q-wave myocardial infarction at the initial emergency coronary artery bypass, age older than 65 years, angina class III or IV, and prior coronary bypass surgery. In spite of a continuing high incidence of early acute myocardial infarction and an increasing operative mortality rate (7%) in the latest 3 years cohort of patients, excellent late survival and low subsequent cardiac event

  12. Percutaneous transluminal angioplasty in a patient with chronic cerebrospinal venous insufficiency and persistent left superior vena cava.

    Science.gov (United States)

    Lupattelli, T; Benassi, F; Righi, E; Bavera, P; Bellagamba, G

    2014-04-01

    Chronic cerebrospinal venous insufficiency (CCSVI) is a syndrome characterized by stenoses of the internal jugular veins (IJVs) and/or azygos veins and formation of collateral venous channels. A case of a 57-year-old patient with CCSVI in whom the venous outflow from the left IJV to the right atrium occurred through a venous anomaly, the persistent left superior vena cava (PLSVC), is reported. PLSVC is caused by persistence of the left anterior cardinal vein that drains blood from the limb effluent from the left and the left side of head and neck into coronary sinus (Type a), or in the left atrium (Type b). PLSVC can be associated either with innominate vein hypoplasia or other congenital heart abnormalities. Because of evidence of left innominate vein hypoplasia, angioplasty was not performed using the ordinary route but passing with the balloon directly through the PLSVC up to the left IJV. Finally, angioplasty was carried out in a standard manner in the right IJV as well as in the azygous vein. Confirmation angiogram revealed complete reopening of all treated vessels with no evidence of peri- and postoperative complications. The patient was discharged home the following day in good general conditions. PLSVC is a rare congenital vein anomaly but in case of concomitant innominate vein hypoplasia may prove to be a valuable alternative to treat patients with IJV diseases.

  13. Self-consistent Kinetic Description of the Low-Pressure Solenoidal Inductively Coupled Argon Discharge

    Institute of Scientific and Technical Information of China (English)

    毛明; 王友年

    2005-01-01

    Using an one-dimensional slab model, we have studied the electron energy distribution, the anomalous skin effect, and power absorption in the solenoidal-inductively-coupled argon discharge under low pressures (≤1.33 Pa). The electron energy distribution function and rf electromagnetic field in the plasma are determined self-consistently by the linearized Bolztmann equation incorporating with the Maxwell equations. The numerical results show that, at low pressures, the electron energy distribution function exhibits a non-Maxwellian distribution with a long high-energy tail. The anomalous skin effect is greatly enhanced under low pressures and the negative power absorption is also obtained.

  14. Aggressive plaque modification with rotational atherectomy and cutting balloon for optimal stent expansion in calcified lesions

    Science.gov (United States)

    Tang, Zhe; Bai, Jing; Su, Shao-Ping; Lee, Pui-Wai; Peng, Liang; Zhang, Tao; Sun, Ting; Nong, Jing-Guo; Li, Tian-De; Wang, Yu

    2016-01-01

    Objective To evaluate the factors affecting optimal stent expansion in calcified lesions treated by aggressive plaque modification with rotational atherectomy (RA) and a cutting balloon (CB). Methods From January 2014 to May 2015, 92 patients with moderate to severe coronary calcified lesions underwent rotational atherectomy and intravascular ultrasound imaging at Chinese PLA General Hospital (Beijing, China) were included in this study. They were divided into a rotational artherectomy combined with cutting balloon (RACB) group (46 patients treated with RA followed by CB angioplasty) and an RA group (46 patients treated with RA followed by plain balloon angioplasty). Another 40 patients with similar severity of their calcified lesions treated with plain old balloon angioplasty (POBA) were demographically matched to the other groups and defined as the POBA group. All patients received a drug-eluting stent after plaque preparation. Lumen diameter and lumen diameter stenosis (LDS) were measured by quantitative coronary angiography at baseline, after RA, after dilatation, and after stenting. Optimal stent expansion was defined as the final LDS < 10%. Results The initial and post-RA LDS values were similar among the three groups. However, after dilatation, the LDS significantly decreased in the RACB group (from 54.5% ± 8.9% to 36.1% ± 7.1%) but only moderately decreased (from 55.7% ± 7.8% to 46.9% ± 9.4%) in the RA group (time × group, P < 0.001). After stenting, there was a higher rate of optimal stent expansion in the RACB group (71.7% in the RACB group, 54.5% in the RA group, and 15% in the POBA group, P < 0.001), and the final LDS was significantly diminished in the RACB group compared to the other two groups (6.0% ± 2.3%, 10.8% ± 3.3%, 12.7% ± 2.1%, P < 0.001). Moreover, an LDS ≤ 40% after plaque preparation (OR = 2.994, 95% CI: 1.297–6.911) was associated with optimal stent expansion, which also had a positive correlation with the appearance of a

  15. Performance of the low pressure MWPCs for fission fragments under a high background%Performance of the low pressure MWPCs for fission fragments under a high background

    Institute of Scientific and Technical Information of China (English)

    宋玉收; Margaryan A.; 胡碧涛; 唐力光

    2011-01-01

    Two couples of low pressure multi-wire proportional chambers (MWPC) were located in the target chamber to detect fission fragments in a hypernuclei producing experiment at Thomas Jefferson National Laboratory (Jlab). In the experiment, a continuous wave (

  16. US Monthly Pilot Balloon Observations

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Monthly winds aloft summary forms summarizing Pilot Balloon observational data for the United States. Generally labeled as Form 1114, and then transitioning to Form...

  17. US Daily Pilot Balloon Observations

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Pilot Balloon observational forms for the United States. Taken by Weather Bureau and U.S. Army observers. Period of record 1918-1960. Records scanned from the NCDC...

  18. US Air Force Balloon Observations

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Worksheets containing pilot balloon data computed from releases at Air Force stations in the western United States. Elevation and azimuth angles are used to compute...

  19. The use of balloon atrial septostomy to facilitate difficult transseptal access in patients undergoing catheter ablation for atrial fibrillation.

    Science.gov (United States)

    Zadeh, Andrew A; Cannom, David S; Macrum, Bruce L; Ho, Ivan C

    2011-07-01

    With the increasing number of patients undergoing repeat catheter ablation procedures for atrial fibrillation, it is not uncommon to encounter a fibrotic interatrial septum that resists the conventional manual advancement of the transseptal sheath. Forceful advancement of the transseptal apparatus can reduce fine control and potentially lead to a higher rate of perforation. We report a case where adjunctive balloon atrial septostomy was used to facilitate transseptal access in a patient with fibrotic interatrial septum. Using a small-caliber angioplasty balloon and under direct fluoroscopic and transesophageal echocardiogram visualization, balloon septostomy was performed with hand inflation until a "waist" was seen. This technique provides a safe way to control the size of the transseptal access created, and allows the passage of a relatively soft-tipped transseptal sheath across a resistive septum. To our knowledge this is the first published use of balloon atrial septostomy during transseptal puncture for left atrium access in a catheter ablation procedure. Balloon atrial septostomy should be considered as an alternative technique for safe transseptal cannulation in select patients in the electrophysiology laboratory or other interventional procedures requiring left atrial access or delivery of large-caliber catheters or sheaths. © 2010 Wiley Periodicals, Inc.

  20. Superpressure Tow Balloon for Extending Durations and Modifying Trajectories of High Altitude Balloon Systems Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The proposed innovation involves the concept of using a Superpressure Tow Balloon (STB) with existing NASA high altitude balloon designs to form a tandem balloon...

  1. Angioplasty and stent treatment of transplant renal artery stenosis.

    Science.gov (United States)

    Del Pozo, Maitane; Martí, Jordi; Guirado, Lluís; Facundo, Carme; Canal, Cristina; de la Torre, Pablo; Ballarín, José; Díaz, Joan M

    2012-07-17

    Transplant renal artery stenosis is a major complication that requires a therapeutic approach involving surgery or angioplasty. The aim of this study was to analyse the evolution of renal transplant patients with renal allograft artery stenosis treated by angioplasty and stent placement. Thirteen patients were diagnosed with transplant renal artery stenosis. Clinical suspicion was based on deterioration of renal function and/or poorly controlled hypertension with compatible Doppler ultrasound findings. The diagnosis was confirmed by arteriography, performing an angioplasty with stent placement during the same operation. A progressive improvement in renal function was observed during the first 3 months after the angioplasty, and renal function then remained stable over 2 years. In addition, blood pressure improved during the first 2 years, and as a consequence there was no need to increase the average number of anti-hypertensive drugs administered (2.5 drugs per patient). In conclusion, angioplasty with stent placement is a safe and effective procedure for the treatment of transplant renal artery stenosis.

  2. Isolated calcification of tricuspid valve with severe low pressure tricuspid regurgitation in an infant

    OpenAIRE

    Mittal, S.R.

    2013-01-01

    A three-month-old asymptomatic male infant was evaluated for a systolic murmur. Echocardiography revealed calcification of tricuspid leaflets with severe low pressure tricuspid regurgitation. Pulmonary artery flow was normal. There was no other congenital anomaly.

  3. Isolated calcification of tricuspid valve with severe low pressure tricuspid regurgitation in an infant.

    Science.gov (United States)

    Mittal, S R

    2013-12-01

    A three-month-old asymptomatic male infant was evaluated for a systolic murmur. Echocardiography revealed calcification of tricuspid leaflets with severe low pressure tricuspid regurgitation. Pulmonary artery flow was normal. There was no other congenital anomaly.

  4. Stochastic Theory of Dust-Grain Charging in Low-Pressure Plasmas

    CERN Document Server

    Abolmasov, S N; Cabarrocas, P Roca i

    2013-01-01

    Charging of dust grains in low-pressure plasmas is reviewed critically. A theory based on the Fokker-Planck equation and orbital motion limited approximation is proposed. The theory predicts that dust grains can acquire a positive charge in low-pressure electropositive plasmas having a sufficiently high plasma potential, in agreement with experimental observations. It is also shown that variations in the plasma potential (electron temperature) can lead to spatial regions in which grains have opposite charges.

  5. Spectroscopic Investigation of Indium Halides as Substitutes of Mercury in Low Pressure Discharges for Lighting Applications

    OpenAIRE

    Briefi, Stefan

    2012-01-01

    Low pressure discharges with indium halides as radiator are discussed as substitutes for hazardous mercury in conventional fluorescent lamps. In this work, the applicability of InBr and InCl in a low pressure discharge light source is investigated. The aim is to identify and understand the physical processes which determine the discharge characteristics and the efficiency of the generated near-UV emission of the indium halide molecule and of the indium atom which is created due to dissociatio...

  6. Simple balloon dilation for drug-eluting in-stent restenosis: An optical coherent tomography analysis

    Energy Technology Data Exchange (ETDEWEB)

    Arikawa, Ryo [Division of Cardiology, Tenyoukai Central Hospital, Izumi-cho, Kagoshima City, Kagoshima (Japan); Yamaguchi, Hiroshi, E-mail: hyamaguchi@tsm.bbiq.jp [Division of Cardiology, Tenyoukai Central Hospital, Izumi-cho, Kagoshima City, Kagoshima (Japan); Takaoka, Junichiro; Miyamura, Akihiro; Atsuchi, Nobuhiko; Ninomiya, Toshiko; Atsuchi, Yoshihiko [Division of Cardiology, Tenyoukai Central Hospital, Izumi-cho, Kagoshima City, Kagoshima (Japan); Ohishi, Mitsuru [Department of Cardiovascular Medicine and Hypertension, Graduate School of Medical and Dental Science, Kagoshima University, Kagoshima (Japan); Terashima, Mitsuyasu [Department of Cardiology, Toyohashi Heart Center, Toyohashi (Japan); Kaneda, Hideaki [Okinaka Memorial Institute for Medical Research, Tokyo (Japan)

    2015-01-15

    Background: Although drug-eluting stent (DES) has significantly reduced restenosis, the treatment of DES-in-stent restenosis (ISR) remains a challenge with high restenosis rate. Methods: We examined whether morphologic appearance of restenosis tissue by optical coherent tomography (OCT) had an impact on outcomes after balloon angioplasty for DES-ISR. The morphologic appearance of restenosis tissue was qualitatively assessed for tissue structures such as homogeneous, layered, and heterogeneous patterns. Results: Using OCT, 50 patients with DES-ISR were divided into 2 groups: 25 lesions with homogeneous or layered patterns (homo/layered group) and 25 lesions with heterogeneous patterns (hetero group). Acute gain was larger in the hetero group (1.33 ± 0.41 mm vs. 1.06 ± 0.32 mm in the homo/layered group, P = 0.03). On intravascular ultrasound analysis, post-procedural percent neointimal area was smaller in the hetero group (27.4 ± 9.2% vs. 34.0 ± 11.2% in the homo/layered group, P = 0.05). Angiographic follow-up was performed in 37 lesions (74%). Follow-up minimal lumen diameter was larger in the hetero group (1.75 ± 0.89 mm vs. 1.01 ± 0.81 mm in the homo/layered group, P = 0.04). Target lesion revascularization rates tended to be lower in the hetero group (20% vs. 43% in the homo/layered group, P = 0.12). Conclusions: Balloon angioplasty was more effective for DES-ISR with heterogeneous tissue appearance than DES-ISR with homogeneous/layered tissue appearance. OCT assessment of DES-ISR morphology may be a useful adjunct in determining clinical strategies. Simple balloon dilatation is a possible treatment strategy for DES-ISR lesions with a heterogeneous appearance on OCT images.

  7. [Percutaneous renal angioplasty. Experience of the Radiodiagnostic Service of the Hotel-Dieu of France].

    Science.gov (United States)

    Atallah, N; Smayra, T; Slaba, S; Menassa, L

    1998-01-01

    We report on a series of 42 renal artery stenosis treated with percutaneous transluminal angioplasty (PTA). From January 1988 to June 1996, these 42 renal artery stenoses were found in 33 patients (17 males and 16 females) who had a balloon dilation (with 3 stent deployment); 9 of these lesions were bilateral and 7 on a single kidney. Initially, 32 patients had a high blood pressure and 6 a progressive renal failure. Twenty-two patients presented an atheromatous pathology, 7 a fibromuscular dysplasia. One patient had a Takayasu arteritis, and 3 others a stenosis of the renal graft artery. We find a complete initial success in 86% of the patients, a partial success in 14% without any catheterization failure. Global success rate of PTA is 90% at 29 months mean follow-up. A benefit of PTA regarding blood pressure was found in 84.4% of the patients. The renal function became normal in half the patients with renal insufficiency. PTA is an efficient treatment for renal artery stenosis. A satisfactory improvement of blood pressure and renal function is found in a high number of patients.

  8. Percutaneous transluminal angioplasty of a non-mainstream venous route to restore an occluded hemodialysis fistula.

    Science.gov (United States)

    Miyayama, Shiro; Yamashiro, Masashi; Ikuno, Masaya; Okumura, Kenichiro; Yoshida, Miki; Kato, Tamayo; Ushiogi, Yasuyuki

    2014-02-01

    To report the usefulness of percutaneous transluminal angioplasty (PTA) of a non-mainstream venous route in an occluded native hemodialysis fistula when a mainstream outflow vein could not be traversed. This cohort included seven patients with an occulted hemodialysis fistula with difficulty in traversing via a mainstream route. A non-mainstream vein near the occluded portion was traversed until it connected with a proximal large-sized vein and the route was dilated using a 4- or 5-mm balloon catheter. Metallic stent placement was performed, if necessary. Technical aspects and long-term patency was evaluated. PTA could be performed in all patients; however, stent placement was required in two because of residual stenosis and clotting. The clinical success rate of fistula restoration was 100 %. Fistula dysfunction recurred in six patients 17-668 days (mean ± standard deviation 229.3 ± 225.0) later. PTA was repeated in four patients, but not in two. The mean duration of the primary patency was 336.6 ± 417.2 days (range 17-1,190) and that of the secondary patency was 897.1 ± 801.4 days (range 17-2,230). PTA of a non-mainstream venous route is useful for restoring an occluded hemodialysis fistula when the mainstream outflow vein cannot be traversed.

  9. Limb-salvage angioplasty in poor surgical chronic liver disease and diabetic patients.

    Science.gov (United States)

    Hamdy, Hussam; El-Kolly, M; Ezzat, H; Abbas, M; Farouk, Y; Naser, M; Magdy, M; Elraouf, A

    2013-08-01

    Critical limb ischemia (CLI) in high surgical risk patients with chronic liver diseases has a grave prognosis with a one-year mortality rate of 20% and a one-year amputation rate of 25% after the initial diagnosis. According to Trans-Atlantic Inter-Society Consensus (TASC)-II Guidelines, revascularization (surgical & endovascular) is the treatment of choice for patients with critical limb ischemia (CLI). The primary goal of revascularization is to relieve ischemic rest pain, heal ulcers, prevent amputation, improve patient's quality of life (limb salvage) and secondary goal was the periprocedural complications. Endovascular techniques include balloon angioplasty, stents, stent-grafts, and plaque debulking procedures. Surgical options, identification of patients at risk of postoperative complications could have an impact on the indications for a procedure as well as permitting modifications of treatment to reduce the surgical risk This study evaluated the treatment out comas after limb salvage angioplasty for patients who otherwise would be candidates for primary amputation due to poor co-morbid conditions as chronic liver disease and diabetes. The clinical evaluation, laboratory investigations and abdominal ultrasonography were performed to all patients to evaluate their liver status. Patients were classified according to Child-pugh classification into child A, B & C. All patients were subjected to either detailed arterial duplex or C.T. angiography to assess their arterial lesions from January 2008- January 2010. 95 patients with critical limb ischemia (Rutherford categories 4, 5, 6) were treated by primary percutaneous transluminal angioplasty (PTA). No patient was excluded on the basis of the extent of arterial occlusive disease. The primary end points were immediate technical success, clinical improvement and limb salvages rates. Secondary end points were periprocedural complications and mortality. Most of the patients were male (54.7%) with mean age 62 (48

  10. Excimer laser assisted angioplasty in hemodialysis access intervention.

    Science.gov (United States)

    Yevzlin, Alexander S; Urbanes, Aris

    2009-01-01

    A case is described in which an excimer laser is used to assist angioplasty of a severe central venous lesion that is refractory to conventional techniques. Modern laser technology uses the ultraviolet (UV) spectral region to generate nanosecond pulses of energy. This results in photoablation, which is the process by which energy photons cause molecular bond disruption, while minimizing thermal damage to the surrounding vascular tissues. Further investigation of excimer laser assisted angioplasty in the setting of hemodialysis access intervention is needed to rigorously define its potential role. In occlusive disease where no conventional alternative is available, however, laser therapy is a viable option.

  11. Drug-Coated Balloon Venoplasty for In-Stent Restenosis in a Patient With Recurrent Pulmonary Vein Stenosis Post Ablation for Atrial Fibrillation: Initial Experience With a New Treatment Technique.

    Science.gov (United States)

    Rosenberg, Jonathan; Fisher, Westby G; Guerrero, Mayra; Smart, Steve; Levisay, Justin; Feldman, Ted; Salinger, Michael

    2016-05-01

    Pulmonary vein stenosis (PVS) is an uncommon but serious complication following radiofrequency ablation for atrial fibrillation. Occurrence of this complication has risen with increased rates of ablation procedures, with >50,000 AF ablation procedures performed per year, and can occur within weeks to months post procedure. Currently, the main therapies for PVS include percutaneous interventions with balloon angioplasty and stenting, but these treatments are complicated by a high rate of restenosis. The optimal treatment for recurrent pulmonary vein in-stent restenosis has not been determined. We describe the novel use of a paclitaxel drug-coated balloon for the treatment of in-stent restenosis of the pulmonary veins.

  12. Development of novel short-term heating angioplasty: diameter and elasticity change of vascular wall ex vivo

    Science.gov (United States)

    Shimazaki, Natsumi; Kaneko, Kenji; Nakatani, Eriko; Arai, Tsunenori

    2007-02-01

    In order to investigate the optimum operation parameters on novel short-term heating (angioplasty in which we demonstrated sufficient vascular dilatation with lower pressure by heat- induced denaturation of arterial collagen. And we have also demonstrated the suppression of intimal hyperplasia in animal experiments. We need to understand the PTDB dilatation mechanism to determine the optimum operation parameters. The prototype PTDB with diameter of 3mm was used in our experiments. The internal diameters of extracted fresh porcine carotid arteries at pre- and post- PTDB dilatation were measured. Balloon parameters were follows; pressure P=2atm, peak temperature in balloon T=60-80 °C, and heating duration t=4-30s. Morphological change in the media of dilated artery with PTDB were microscopically examined with Weigert staining. Elastic properties were carried out by stress-strain measurements with calculation of young's modulus. We found that PTDB dilatation provided the effect to prevent elastic recoil. We explained that the reason of this effect might be arrangement of micro- structure in the media, i.e., heat-denatured collagen fibers sustained the elastic recoil due to rubbery elastin fibers. The arterial elasticity was not significant different after PTDB dilatation. It was suggested that there could be no compliance mismatch after PTDB dilatation in physiological range. We found that a part of PTDB dilatation mechanism, in which the vascular wall structure played an important role. The optimum operation parameters for PTDB might be determined in consideration of collagen denaturation progress and arterial composition.

  13. Sensor System for Super-Pressure Balloon Performance Modeling Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Long-duration balloon flights are an exciting new area of scientific ballooning, enabled by the development of large super-pressure balloons. As these balloons...

  14. Low Pressure Tolerance by Methanogens in an Aqueous Environment: Implications for Subsurface Life on Mars

    Science.gov (United States)

    Mickol, R. L.; Kral, T. A.

    2016-09-01

    The low pressure at the surface of Mars (average: 6 mbar) is one potentially biocidal factor that any extant life on the planet would need to endure. Near subsurface life, while shielded from ultraviolet radiation, would also be exposed to this low pressure environment, as the atmospheric gas-phase pressure increases very gradually with depth. Few studies have focused on low pressure as inhibitory to the growth or survival of organisms. However, recent work has uncovered a potential constraint to bacterial growth below 25 mbar. The study reported here tested the survivability of four methanogen species (Methanothermobacter wolfeii, Methanosarcina barkeri, Methanobacterium formicicum, Methanococcus maripaludis) under low pressure conditions approaching average martian surface pressure (6 mbar - 143 mbar) in an aqueous environment. Each of the four species survived exposure of varying length (3 days - 21 days) at pressures down to 6 mbar. This research is an important stepping-stone to determining if methanogens can actively metabolize/grow under these low pressures. Additionally, the recently discovered recurring slope lineae suggest that liquid water columns may connect the surface to deeper levels in the subsurface. If that is the case, any organism being transported in the water column would encounter the changing pressures during the transport.

  15. Growth and mitochondrial respiration of mungbeans (Phaseolus aureus Roxb.) germinated at low pressure

    Science.gov (United States)

    Musgrave, M. E.; Gerth, W. A.; Scheld, H. W.; Strain, B. R.

    1988-01-01

    Mungbean (Phaseolus aureus Roxb.) seedlings were grown hypobarically to assess the effects of low pressure (21-24 kilopascals) on growth and mitochondrial respiration. Control seedlings grown at ambient pressure (101 kilopascals) were provided amounts of O2 equivalent to those provided experimental seedlings at reduced pressure to factor out responses to O2 concentration and to total pressure. Respiration was assayed using washed mitochondria, and was found to respond only to O2 concentration. Regardless of total pressure, seedlings grown at 2 millimoles O2 per liter had higher state 3 respiration rates and decreased percentages of alternative respiration compared to ambient (8.4 millimoles O2 per liter) controls. In contrast, seedling growth responded to total pressure but not to O2 concentration. Seedlings were significantly larger when grown under low pressure. While low O2 (2 millimoles O2 per liter) diminished growth at ambient pressure, growth at low pressure in the same oxygen concentration was enhanced. Respiratory development and growth of mungbean seedlings under low pressure is unimpaired whether oxygen or air is used as the chamber gas, and further, low pressure can improve growth under conditions of poor aeration.

  16. Balloon Exoplanet Nulling Interferometer (BENI)

    Science.gov (United States)

    Lyon, Richard G.; Clampin, Mark; Woodruff, Robert A.; Vasudevan, Gopal; Ford, Holland; Petro, Larry; Herman, Jay; Rinehart, Stephen; Carpenter, Kenneth; Marzouk, Joe

    2009-01-01

    We evaluate the feasibility of using a balloon-borne nulling interferometer to detect and characterize exosolar planets and debris disks. The existing instrument consists of a 3-telescope Fizeau imaging interferometer with 3 fast steering mirrors and 3 delay lines operating at 800 Hz for closed-loop control of wavefront errors and fine pointing. A compact visible nulling interferometer is under development which when coupled to the imaging interferometer would in-principle allow deep suppression of starlight. We have conducted atmospheric simulations of the environment above 100,000 feet and believe balloons are a feasible path forward towards detection and characterization of a limited set of exoplanets and their debris disks. Herein we will discuss the BENI instrument, the balloon environment and the feasibility of such as mission.

  17. Structure variations of pumpkin balloon

    Science.gov (United States)

    Yajima, N.; Izutsu, N.; Honda, H.

    2004-01-01

    A lobed pumpkin balloon by 3-D gore design concept is recognized as a basic form for a super-pressure balloon. This paper deals with extensions of this design concept for other large pressurized membrane structures, such as a stratospheric airship and a balloon of which volume is controllable. The structural modifications are performed by means of additional ropes, belts or a strut. When the original pumpkin shape is modified by these systems, the superior characteristics of the 3-D gore design, incorporating large bulges with a small local radius and unidirectional film tension, should be maintained. Improved design methods which are adequate for the above subjects will be discussed in detail. Application for ground structures are also mentioned.

  18. Yellow Balloon in a Briar Patch.

    Science.gov (United States)

    Cooper, Frank; Fitzmaurice, Robert W.

    1978-01-01

    As part of a meteorology unit, sixth grade science students launched helium balloons with attached return postcards. This article describes Weather Service monitoring of the balloons and postcard return results. (MA)

  19. Early rethrombosis in femoropopliteal occlusions treated with percutaneous transluminal angioplasty

    DEFF Research Database (Denmark)

    Jørgensen, B; Meisner, S; Holstein, P;

    1990-01-01

    One hundred and thirty-seven consecutive percutaneous transluminal angioplasties (PTA) were performed for femoropopliteal vascular disease including 58 stenoses and 79 total occlusions. Nine occlusions could not be crossed with the guidewire, but in the remaining 128 the haemodynamic and clinical...

  20. Subintimal angioplasty: predictors of long-term success.

    LENUS (Irish Health Repository)

    Keeling, Aoife N

    2009-08-01

    To determine the clinical outcomes and success rates after percutaneous subintimal angioplasty (SIA) in patients with lower-limb occlusive lesions causing intermittent claudication (IC) or critical limb ischemia (CLI) at midterm to long-term follow-up. The secondary aim was to elicit factors predictive of a successful outcome.

  1. A meta-analytic overview of thrombectomy during primary angioplasty

    NARCIS (Netherlands)

    Luca, G. De; Navarese, E.P.; Suryapranata, H.

    2013-01-01

    INTRODUCTION: Even though primary angioplasty restores TIMI 3 flow in more than 90% of STEMI patients, the results in terms of myocardial perfusion are still unsatisfactory in a relatively large proportion of patients. Great interest has been focused in the last years on distal embolization as major

  2. Monitoring of low pressure plasma systems; Ueberwachung von Niederdruck-Plasmaanlagen

    Energy Technology Data Exchange (ETDEWEB)

    Michaeli, W.; Hegenbart, A.; Binkowski, D.; Fragstein, F. v. [Inst. fuer Kunststoffverarbeitung (IKV) an der RWTH Aachen (Germany)

    2007-02-15

    The optical emission spectroscopy (OES) is a very flexible and easy to use method to monitor industrial plasma processes. By directly monitoring the plasma itself many additional factors influencing low pressure plasma processes can be observed. First of all factors that can not be controlled directly play an important role in this context. Examples are contaminations and leaks in the plasma system. These can negatively influence the reproducibility of production processes. In this paper the effect of a leak on the coating and the plasma process is being shown. Additionally the detection of contaminations and sealing problems in a microwave plasma source is being demonstrated. By using the correlations being presented the OES can be used to continually monitor low pressure plasma systems and thus enhance reproducibility of industrial low pressure plasma processes. (orig.)

  3. Bulk characterization of pharmaceutical powders by low-pressure compression II

    DEFF Research Database (Denmark)

    Hagsten Sørensen, A.; Sonnergaard, Jørn; Hovgaard, L.

    2006-01-01

    The aim of the present study was to investigate the effect of punch and die diameter, sample size, compression speed, and particle size on two low-pressure compression-derived parameters; the compressed density and the Walker w parameter. The excellent repeatability of the low-pressure compression...... method allowed small effects of variations in punch and die diameter and sample size to be demonstrated on a high significance level. Changing the compression speed, however, did not cause a significant effect in the compressed density, whereas a decrease in w was seen. The effect of particle size...... was studied by compressing and tapping different grades of calcium carbonate, lactose, and microcrystalline cellulose. The low-pressure compression-derived parameters were compared to tapped densities and to Compressibility Indexes obtained by tapping volumetry. Even though the relationship between particle...

  4. Treatment of refractory low-pressure hydrocephalus with an active pumping negative-pressure shunt system.

    Science.gov (United States)

    Kalani, M Yashar S; Turner, Jay D; Nakaji, Peter

    2013-03-01

    Low-pressure hydrocephalus is a rare type of hydrocephalus characterized by negative intracranial pressure (ICP) and ventriculomegaly. Given the shortcomings of available methods to treat refractory low-pressure hydrocephalus, we set out to develop a new system for evacuation of cerebrospinal fluid (CSF) from the ventricular system where existing shunt systems do not produce the necessary gradient for CSF drainage. We retrospectively reviewed the charts of two patients with the diagnosis of negative-pressure hydrocephalus refractory to traditional treatments. We combined a traditional low-pressure, non-siphoning valve with a pumping chamber placed distal to the valve to create a system that could be actively pumped to remove excess CSF. Treatment of negative-pressure hydrocephalus requires the establishment of a lower ventricular drainage pressure than the drainage pressure in the subarachnoid space. In refractory cases, we propose the use of this active negative-pressure pumping system.

  5. Ballonnen in zee = balloons as marine litter

    NARCIS (Netherlands)

    Franeker, van J.A.

    2008-01-01

    Releasing balloons seems harmless. However, remains of balloons, especially valves and ribbons are becoming a common and persistent type of marine litter found on beaches. Following Dutch Queens day 2007, large numbers of Dutch balloons were found in Normandy, France. Animals may become entangled in

  6. Complications of balloon packing in epistaxis

    NARCIS (Netherlands)

    Vermeeren, Lenka; Derks, Wynia; Fokkens, Wytske; Menger, Dirk Jan

    2015-01-01

    Although balloon packing appears to be efficient to control epistaxis, severe local complications can occur. We describe four patients with local lesions after balloon packing. Prolonged balloon packing can cause damage to nasal mucosa, septum and alar skin (nasal mucosa, the cartilaginous skeleton

  7. Ballonnen in zee = balloons as marine litter

    NARCIS (Netherlands)

    Franeker, van J.A.

    2008-01-01

    Releasing balloons seems harmless. However, remains of balloons, especially valves and ribbons are becoming a common and persistent type of marine litter found on beaches. Following Dutch Queens day 2007, large numbers of Dutch balloons were found in Normandy, France. Animals may become entangled in

  8. Low-pressure airlift fermenter for single cell protein production: II. Continuous culture of Pichia yeast

    Energy Technology Data Exchange (ETDEWEB)

    Chen, N.Y.; Srinivasan, S.; Leavitt, R.I.; Coty, V.F.; Kondis, E.F.

    1987-03-01

    Experiments using Pichia yeast grown on n-paraffins have been conducted in laboratory 10-l airlift fermenters and in a 640-l module of commercial scale. Results confirmed the design concept with low-pressure air. However, in the absence of mass transport constraints, the build up of toxic factors in the fermenter appeared to a major variable limiting cell productivity. Foaming in the large fermenter also presented a serious problem, which must be solved before low-pressure airlift fermenters become practical. 14 references.

  9. Over recovery in low pressure sparkgaps - confirmation of pressure reduction in over recovery

    OpenAIRE

    Nagesh, KV; Ron, PH; Nagabhushana, GR; Nema, RS

    1999-01-01

    The over recovery in sparkgaps [1], [2] operating along the left-hand side of Paschens characteristics is due to pressure reduction in the gap after the first pulse discharge. This pressure reduction leading to over recovery in low pressure sparkgaps has been verified using a low pressure sparkgap with two sparkgaps placed one above the other in the same chamber. The breakdown voltage strength characteristics of the second gap has been determined for gap spacings of 3.5 mm to 10 mm, diffusion...

  10. Germination of white radish, buckwheat and qing-geng-cai under low pressure in closed environment.

    Science.gov (United States)

    Hinokuchi, Tsutomu; Oshima, Satoshi; Hashimoto, Hirofumi

    2004-11-01

    In order to cultivate plants under low pressure in closed environment, the germination rate of seeds of white radish was investigated under low pressure, low oxygen partial pressure and condition of pure oxygen. The result of these experiments showed that the germination rate was affected by the oxygen partial pressure. From this fact, it is possible to lower the total pressure by using only the pure oxygen in germination. Furthermore, the germination rates of seeds of buckwheat and qing-geng-cai were also investigated in pure oxygen for the comparison. Consequently, though tendency in germination rate of white radish was similar to qing-geng-cai, it was different from buckwheat.

  11. On the mechanism of low-pressure imprint lithography: capillarity vs viscous flow.

    Science.gov (United States)

    Khang, Dahl-Young; Lee, Hong H

    2008-05-20

    Dominant mechanisms in low-pressure imprint lithography processes have been identified for the regimes that are definable in terms of applied pressure, temperature, and mold material characteristics. Capillarity is found to be the dominant mechanism at high temperature and low pressure when stiff, hard molds are used. In the case of flexible thin-film ( approximately 20 microm) molds, both the capillarity and the viscous flow are involved. Both mechanisms are operative in the initial stage of the imprinting, but the capillarity takes over as time progresses.

  12. Meteorological Support in Scientific Ballooning

    Science.gov (United States)

    Schwantes, Chris; Mullenax, Robert

    2017-01-01

    The weather affects every portion of a scientific balloon mission, from payload integration to launch, float, and impact and recovery. Forecasting for these missions is very specialized and unique in many aspects. CSBF Meteorology incorporates data from NWSNCEP, as well as several international meteorological organizations, and NCAR. This presentation will detail the tools used and specifics on how CSBF Meteorology produces its forecasts.

  13. Simulating clefts in pumpkin balloons

    Science.gov (United States)

    Baginski, Frank; Brakke, Kenneth

    2010-02-01

    The geometry of a large axisymmetric balloon with positive differential pressure, such as a sphere, leads to very high film stresses. These stresses can be significantly reduced by using a tendon re-enforced lobed pumpkin-like shape. A number of schemes have been proposed to achieve a cyclically symmetric pumpkin shape, including the constant bulge angle (CBA) design, the constant bulge radius (CBR) design, CBA/CBR hybrids, and NASA’s recent constant stress (CS) design. Utilizing a hybrid CBA/CBR pumpkin design, Flight 555-NT in June 2006 formed an S-cleft and was unable to fully deploy. In order to better understand the S-cleft phenomenon, a series of inflation tests involving four 27-m diameter 200-gore pumpkin balloons were conducted in 2007. One of the test vehicles was a 1/3-scale mockup of the Flight 555-NT balloon. Using an inflation procedure intended to mimic ascent, the 1/3-scale mockup developed an S-cleft feature strikingly similar to the one observed in Flight 555-NT. Our analysis of the 1/3-scale mockup found it to be unstable. We compute asymmetric equilibrium configurations of this balloon, including shapes with an S-cleft feature.

  14. Stability of the pumpkin balloon

    Science.gov (United States)

    Baginski, Frank

    A large axisymmetric balloon with positive differential pressure, e.g., a sphere, leads to high film stresses. These can be significantly reduced by using a lobed pumpkin-like shape re-enforced with tendons. A number of schemes have been proposed to achieve a cyclically symmetric pumpkin-shape at full inflation, including the constant bulge angle (CBA) design and the constant bulge radius (CBR) design. The authors and others have carried out stability studies of CBA and CBR designs and found instabilities under various conditions. While stability seems to be a good indicator of deployment problems for large balloons under normal ascent conditions, one cannot conclude that a stable design will deploy reliably. Nevertheless, stability analysis allows one to quantify certain deployment characteristics. Ongoing research by NASA's Balloon Program Office utilizes a new design approach developed by Rodger Farley, NASA/GSFC, that takes into account film and tendon strain. We refer to such a balloon as a constant stress (CS) pumpkin design. In June 2006, the Flight 555-NT balloon (based on a hybrid CBR/CBA design) developed an S-cleft and did not deploy. In order to understand the S-cleft phenomena and study a number of aspects related to the CS-design, a series of inflation tests were conducted at TCOM, Elizabeth City, NC in 2007. The test vehicles were 27 meter diameter pumpkins distinguished by their respective equatorial bulge angles (BA). For example, BA98 indicates an equatorial bulge angle of 98° . BA90, BA55, and BA00 are similarly defined. BA98 was essentially a one-third scale version of of the Flight 555 balloon (i.e., 12 micron film instead of 38.1 micron, mini-tendons, etc.). BA90 and BA55 were Farley CS-designs. BA00 was derived from the BA55 design so that a flat chord spanned adjacent tendons. In this paper, we will carry out stability studies of BA98, BA90, BA55, and BA00. We discuss the deployment problem of pumpkin balloons in light of 2007 inflation

  15. Early outcome of high energy Laser (Excimer) facilitated coronary angioplasty ON hARD and complex calcified and balloOn-resistant coronary lesions: LEONARDO Study

    Energy Technology Data Exchange (ETDEWEB)

    Ambrosini, Vittorio; Sorropago, Giovanni; Laurenzano, Eugenio [Montevergine Clinic, Mercogliano (Italy); Golino, Luca, E-mail: lucagolino.jazz@alice.it [Montevergine Clinic, Mercogliano (Italy); Moriggia-Pelascini Hospital, Gravedona, Como (Italy); Casafina, Alfredo; Schiano, Vittorio [Montevergine Clinic, Mercogliano (Italy); Gabrielli, Gabriele [University Hospital Ospedali Riuniti, Ancona (Italy); Ettori, Federica; Chizzola, Giuliano [Spedali Civili University Hospital, Brescia (Italy); Bernardi, Guglielmo; Spedicato, Leonardo [University Hospital S. Maria Misericordia, Udine (Italy); Armigliato, Pietro [Istituto Italiano Ricerche Mediche, Verona (Italy); Spampanato, Carmine [Telethon Institute of Genetics and Medicine (TIGEM), Naples (Italy); Furegato, Martina [Istituto Italiano Ricerche Mediche, Verona (Italy)

    2015-04-15

    Aim: An innovative xenon–chlorine (excimer) pulsed laser catheter (ELCA X80) has been recently used for the treatment of complex coronary lesions, as calcified stenosis, chronic total occlusions and non-compliant plaques. Such complex lesions are difficult to adequately treat with balloon angioplasty and/or intracoronary stenting. The aim of this study was to examine the acute outcome of this approach on a cohort of patients with coronary lesions. Methods and Results: Eighty patients with 100 lesions were enrolled through four centers, and excimer laser coronary angioplasty was performed on 96 lesions (96%). Safety and effectiveness data were compared between patients treated with standard laser therapy and those treated with increased laser therapy. Laser success was obtained in 90 lesions (93.7%), procedural success was reached in 88 lesions (91.7%), and clinical success in was obtained in 87 lesions (90.6%). There was no perforation, major side branch occlusion, spasm, no-reflow phenomenon, dissection nor acute vessel closure. Increased laser parameters were used successfully for 49 resistant lesions without complications. Conclusions: This study suggests that laser-facilitated coronary angioplasty is a simple, safe and effective device for the management of complex coronary lesions. Furthermore, higher laser energy levels delivered by this catheter improved the device performance without increasing complications. - Highlights: • We planned this multicenter study to examine the acute outcome of an innovative xenon–chlorine (excimer) pulsed laser catheter (ELCA X80) for treatment of complex coronary lesions. • We enrolled 80 patients with 100 lesions and performed excimer laser coronary angioplasty in 96 lesions (96%). • Laser success was obtained in 90 lesions (93.7%), procedural success was reached in 88 lesions (91.7%), and clinical success was obtained in 87 lesions (90.6%). • Increased laser parameters were used successfully for 49 resistant

  16. Percutaneous balloon dilation of Carpentier-Edwards porcine-valved right ventricle-to-pulmonary artery conduits.

    Science.gov (United States)

    Hall, Amanda C; Miga, Daniel E; Leonard, Glenn T; Wang, Hongyue; Kavey, Rae-Ellen; Alfieris, George M

    2013-04-01

    Right ventricular outflow tract (RVOT) conduit stenosis remains a significant problem for patients with right ventricle-to-pulmonary artery (RV-to-PA) conduits placed as palliation for congenital heart disease. Previous reports on balloon dilation of RVOT conduits all describe small series with varying levels of success during limited follow-up evaluation. This study reviewed all patients with RV-to-PA conduits who underwent percutaneous balloon dilation for conduit stenosis at the authors' institution from 2000 to 2011. Patients with Carpentier-Edwards (CE) model 4300 porcine-valved conduits (Edwards Lifesciences Corp., Irvine, CA) (n = 19) were compared with patients who had all other types of conduits (n = 19). Successful balloon angioplasty was defined as a 20 % decrease in the RV-to-PA gradient, a 20 % decrease in the ratio of the RV systolic-to-aortic systolic pressure, or both. Balloon dilation was successful for 57.9 % of the patients with CE conduits and for 31.6 % of patients with other types of conduits (p = 0.10, Chi square test). Logistic regression analysis showed that balloon dilation was significantly more likely to be successful with CE valves than with other types (odds ratio [OR], 6.59; 95 % confidence interval [CI], 1.22-35.49). In a continuous series of patients with stenotic RV-to-PA conduits, the CE porcine-valved conduit was more amenable to percutaneous balloon dilation than other types of RV-to-PA conduits at the midterm follow-up evaluation. This has important ramifications in terms of valve selection for patients with congenital heart disease who will require surgical reintervention for RVOT stenosis.

  17. DNA aptamer raised against advanced glycation end products inhibits neointimal hyperplasia in balloon-injured rat carotid arteries.

    Science.gov (United States)

    Ojima, Ayako; Oda, Eriko; Higashimoto, Yuichiro; Matsui, Takanori; Yamagishi, Sho-ichi

    2014-02-15

    Advanced glycation end products (AGE) and their receptor (RAGE) interaction elicit inflammatory and proliferative reactions in arteries, thus playing a role in cardiovascular disease. We have recently found that high-affinity DNA aptamer directed against AGE (AGE-aptamer) prevents the progression of experimental diabetic nephropathy by blocking the harmful actions of AGEs in the kidney. However, effects of AGE-aptamer on vascular injury remain unknown. In this study, we examined whether and how AGE-aptamer inhibits neointimal hyperplasia in balloon-injured rat carotid arteries. Male Wistar rats (weighting ca. 400 g at 11 weeks old) were anesthetized with sodium pentobarbital. The left common carotid artery was balloon-injured 3 times with 2F Fogaty catheter inserted through the femoral artery. Then the rats received continuous intraperitoneal infusion (3 μg/day) of either AGE-aptamer or control-aptamer by an osmotic mini pump for 2 weeks. 14 days after the procedure, the left common carotid arteries were excised for morphometric, immunohistochemical and western blot analyses. Compared with control-aptamer, AGE-aptamer significantly suppressed neointima formation after balloon injury and reduced AGE accumulation, oxidative stress generation, proliferation cell nuclear antigen-positive area, macrophage infiltration, RAGE and platelet-derived growth factor-BB (PDGF-BB) expression levels in balloon-injured carotid arteries. The present study suggests that AGE-aptamer could prevent balloon injury-induced neointimal hyperplasia by reducing PDGF-BB and macrophage infiltration via suppression of the AGE-RAGE-mediated oxidative stress generation. AGE-aptamer might be a novel therapeutic strategy for suppressing neointima formation after balloon angioplasty. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  18. A challenge to the highest balloon altitude

    Science.gov (United States)

    Saito, Y.; Akita, D.; Fuke, H.; Iijima, I.; Izutsu, N.; Kato, Y.; Kawada, J.; Matsuzaka, Y.; Mizuta, E.; Namiki, M.; Nonaka, N.; Ohta, S.; Sato, T.; Seo, M.; Takada, A.; Tamura, K.; Toriumi, M.; Yamagami, T.; Yamada, K.; Yoshida, T.; Matsushima, K.; Tanaka, S.

    2012-02-01

    Development of a balloon to fly at higher altitudes is one of the most attractive challenges for scientific balloon technologies. After reaching the highest balloon altitude of 53.0 km using the 3.4 μm film in 2002, a thinner balloon film with a thickness of 2.8 μm was developed. A 5000 m3 balloon made with this film was launched successfully in 2004. However, three 60,000 m3 balloons with the same film launched in 2005, 2006, and 2007, failed during ascent. The mechanical properties of the 2.8 μm film were investigated intensively to look for degradation of the ultimate strength and its elongation as compared to the other thicker balloon films. The requirement of the balloon film was also studied using an empirical and a physical model assuming an axis-symmetrical balloon shape and the static pressure. It was found that the film was strong enough. A stress due to the dynamic pressure by the wind shear is considered as the possible reason for the unsuccessful flights. A 80,000 m3 balloon with cap films covering 9 m from the balloon top will be launch in 2011 to test the appropriateness of this reinforcement.

  19. The beauty of frost: nano-sulfur assembly via low pressure vapour deposition.

    Science.gov (United States)

    Wang, Yu; Chen, Lu; Scudiero, Louis; Zhong, Wei-Hong

    2015-11-14

    A low pressure vapour deposition (LPVD) technique is proposed as an environmentally friendly, cost-effective and versatile strategy for fabrication of sulfur nanomaterials. By controlling the characteristics of the deposit substrate for the LPVD, various sulfur-based nanomaterials have been obtained through a substrate-induced self-assembly process.

  20. Numerical Study of Active Flow Control for a Transitional Highly-Loaded Low-Pressure Turbine

    Science.gov (United States)

    2008-02-01

    Count Using Vortex Generator Jet Separation Control,” ASME Paper GT-2002-30602, Jun. 2002. [16] Eulitz, F. and Engel , K., “Numerical Investigation of...Around a Low Pressure Turbine Blade,” Direct and Large-Eddy Simulation IV, ERCOFTAC Series Vol. 8 , edited by B. J. Guerts, R. Friedrich , and O

  1. Gray water recycle: Effect of pretreatment technologies on low pressure reverse osmosis treatment

    Science.gov (United States)

    Gray water can be a valuable source of water when properly treated to reduce the risks associated with chemical and microbial contamination to acceptable levels for the intended reuse application. In this study, the treatment of gray water using low pressure reverse osmosis (RO) filtration after pre...

  2. An Engine Research Program Focused on Low Pressure Turbine Aerodynamic Performance

    Science.gov (United States)

    Castner, Raymond; Wyzykowski, John; Chiapetta, Santo; Adamczyk, John

    2002-01-01

    A comprehensive test program was performed in the Propulsion Systems Laboratory at the NASA Glenn Research Center, Cleveland Ohio using a highly instrumented Pratt and Whitney Canada PW 545 turbofan engine. A key objective of this program was the development of a high-altitude database on small, high-bypass ratio engine performance and operability. In particular, the program documents the impact of altitude (Reynolds Number) on the aero-performance of the low-pressure turbine (fan turbine). A second objective was to assess the ability of a state-of-the-art CFD code to predict the effect of Reynolds number on the efficiency of the low-pressure turbine. CFD simulation performed prior and after the engine tests will be presented and discussed. Key findings are the ability of a state-of-the art CFD code to accurately predict the impact of Reynolds Number on the efficiency and flow capacity of the low-pressure turbine. In addition the CFD simulations showed the turbulent intensity exiting the low-pressure turbine to be high (9%). The level is consistent with measurements taken within an engine.

  3. Low-pressure pneumoperitoneum during laparoscopic donor nephrectomy to optimize live donors' comfort

    NARCIS (Netherlands)

    Warle, M.C.; Berkers, A.W.; Langenhuijsen, J.F.; Jagt, M.F.P. van der; Dooper, P.M.M.; Kloke, H.J.; Pilzecker, D.; Renes, S.H.; Wever, K.E.; Hoitsma, A.J.; Vliet, J.A. van der; D'Ancona, F.C.H.

    2013-01-01

    Nowadays, laparoscopic donor nephrectomy (LDN) has become the gold standard to procure live donor kidneys. As the relationship between donor and recipient loosens, it becomes of even greater importance to optimize safety and comfort of the surgical procedure. Low-pressure pneumoperitoneum has been s

  4. An improved process for high nutrition of germinated brown rice production: Low-pressure plasma.

    Science.gov (United States)

    Chen, Hua Han; Chang, Hung Chia; Chen, Yu Kuo; Hung, Chien Lun; Lin, Su Yi; Chen, Yi Sheng

    2016-01-15

    Brown rice was exposed to low-pressure plasma ranging from 1 to 3kV for 10min. Treatment of brown rice in low-pressure plasma increases the germination percentage, seedling length, and water uptake in laboratory germination tests. Of the various treatments, 3-kV plasma exposure for 10min yielded the best results. In germinating brown rice, α-amylase activity was significantly higher in treated groups than in controls. The higher enzyme activity in plasma-treated brown rice likely triggers the rapid germination and earlier vigor of the seedlings. Low-pressure plasma also increased gamma-aminobutyric acid (GABA) levels from ∼19 to ∼28mg/100g. In addition, a marked increase in the antioxidant activity of brown rice was observed with plasma treatments compared to controls. The main finding of this study indicates that low-pressure plasma is effective at enhancing the growth and GABA accumulation of germinated brown rice, which can supply high nutrition to consumer.

  5. ASSESSING THE EFFECTIVENESS OF LOW PRESSURE ULTRAVIOLET LIGHT FOR INACTIVATING HELICOBACTER PYLORI

    Science.gov (United States)

    Three strains of Helicobacter pylori were exposed to ultraviolet (UV) light from a low-pressure source to determine log inactivation versus applied fluence. Results indicate that H. pylori is readily inactivated at UV fluences typically used in water treatment r...

  6. ASSESSING THE EFFECTIVENESS OF LOW PRESSURE ULTRAVIOLET LIGHT FOR INACTIVATING HELICOBACTER PYLORI

    Science.gov (United States)

    Three strains of Helicobacter pylori were exposed to ultraviolet (UV) light from a low-pressure source to determine log inactivation versus applied fluence. Results indicate that H. pylori is readily inactivated at UV fluences typically used in water treatment r...

  7. Heat transport in cold-wall single-wafer low pressure chemical-vapor-deposition reactors

    NARCIS (Netherlands)

    Hasper, A.; Schmitz, J.E.J.; Holleman, J.; Verweij, J.F.

    1992-01-01

    A model is formulated to understand and predict wafer temperatures in a tungsten low pressure chemical‐vapor‐deposition (LPCVD) single‐wafer cold‐wall reactor equipped with hot plate heating. The temperature control is usually carried out on the hot plate temperature. Large differences can occur

  8. Using the EMD method to determine fault criterion for medium-low pressure gas regulators

    Science.gov (United States)

    Hao, Xuejun; Liu, Qiang; Yang, Guobin; Du, Yi

    2015-11-01

    By extracting the outlet pressure data of gas regulators, this paper uses the EMD toolbox of the MATLAB software, which can perform data decomposition and the Hilbert-Huang Transform to find the rules with fault data. Eventually, the medium-low pressure gas regulator fault criterion can be established.

  9. Numerical approach to a low pressure gas-injection scroll compressor

    OpenAIRE

    Zhou Guang-Hui; Li Hai-Jun; Liu Lei; Zhao Deng-Ke; Wei Pan-Pan; Chen Tong

    2015-01-01

    In order to solve problems arising in ordinary heat pump system for pure electric vehicles at ultra-low temperature, a low pressure gas-injection scroll compressor is designed, and a mathematical model is established. Comparison with the experimental results shows good accuracy of the theoretical prediction.

  10. Optimized surgical space during low-pressure laparoscopy with deep neuromuscular blockade

    DEFF Research Database (Denmark)

    Staehr-Rye, Anne K; Rasmussen, Lars S; Rosenberg, Jacob;

    2013-01-01

    Laparoscopic cholecystectomy (LC) can be performed using low intra-abdominal pressure (space conditions using either deep, continuous muscle relaxation or moderate blockade during low-pressure (8 mm......Hg) LC. We hypothesized that a deep neuromuscular block would be associated with a higher proportion of optimal surgical space conditions....

  11. Highly Loaded Low-Pressure Turbine: Design, Numerical and Experimental Analysis (Preprint)

    Science.gov (United States)

    2010-06-01

    the transition models of Praisner and Clark [19] to determine airfoil performance. Graphical User In- terfaces (GUI) were employed to alter the...Turbomachinery Flows, NASA/CP- 2001-210888, NASA. [5] Hourmouziadis, J., 1984. “Aerodynamic design of low pressure turbines”. In AGARD-LS-167 Blading Desing

  12. Experimental Study of Adenovirus Vector Mediated-hVEGF165 Gene on Prevention of Restenosis after Angioplasty

    Institute of Scientific and Technical Information of China (English)

    刘启功; 陆再英; 岳远坤; 林立; 张卫东; 颜进

    2004-01-01

    This study evaluated the effects of adenovirus vector mediated human vascular endothelial growth factor-165 (hVEGF165) gene on prevention of restenosis after angioplasty. Rabbit models of bilateral carotid artery injury were established by balloon denudation. The recombinant adenoviruses containing hVEGF165 cDNA was directly injected into left side of the injured carotid arteries.On day 3 and week 3 after transfection the expression of VEGF was observed by RT-PCR and immunohistochemistry. The thrombokinesis, reendothelialization (rET) and intimal hyperplasia in carotid arteries were evaluated by computerized image analysis system 3 weeks after gene transfer.The changes in the VEGF gene-treated side were compared with the control side. Our results showed that 3 days and 3 weeks after hVEGF165 gene transfer the VEGF mRNA and antigen expression were detected in vivo. 3 weeks after the transfer, the carotid artery rET was markedly better in the VEGF gene-treated group compared with the control. The thrombokinesis, intima area/media area (I/M), maximal intimal and medial thicknesses (ITmax and MTmax) demonstrated a statistically significant decrease in arteries treated with VEGF gene as compared with the control group. It is concluded that VEGF gene transfer could be achieved by intra-arterial injection of recombinant adenoviruses. It might accelerate the restoration of endothelial integrity, inhibit thrombokinesis and attenuate intimal hyperplasia in the injured arteries after VEGF gene transfer. This procedure could be useful in preventing restenosis after angioplasty.

  13. Percutaneous transluminal angioplasty for atherosclerotic stenosis of the intracranial cerebral arteries. initial results and long-term follow-up.

    Science.gov (United States)

    Hyodo, A; Kato, N; Nakai, Y; Anno, I; Sato, H; Okazaki, M; Matsumaru, Y; Nose, T

    1999-11-01

    Percutaneous transluminal angioplasty (PTA) was carried out 52 times for 49 lesions in 47 cases of atheroscrelotic stenosis of the intracranial or skull base cerebral arteries. The stenotic lesions involved the middle cerebral artery in 21 cases, the basilar artery in eight cases, the internal carotid artery (petrous-supraclinoid portion) in 15 cases, and the intracranial vertebral artery in five cases. Nearly all cases were symptomatic, such as TIA or stroke, and the degree of stenosis ranged from 70 to 99 percent, with a mean of 80 percent. PTA was performed using a STEALTH balloon angioplasty catheter. In these trials, PTA was successfully performed (as indicated by a residual stenosis under 50%) 41 times. The initial success rate was 79% and stenosis was reduced from 80% to 25%. Clinical follow-up was performed from 7 to 84 months with a mean of 44 months. During this period, death due to myocardial infarction or pneumonia occurred in five cases, stroke related to previous PTA occurred ih one case (due to re-stenosis) and stroke unrelated tl? previous PTA occurred in two cases. Angiographic follow-up was performed in 31 cases after 41 successful PTA procedures. Re-stenosis was seen in 20% of the cases, symptomrltic complications occurred in 6%, and asymptomatic complications occurred in 6% of the cases. One case suffered severe subarachnoid hemorrhage just after the PTA due to preexisting aneurysm rupture and he died a week after the PTA. So mortality in this series was 2%. From the results described here, we may conclude that PTA of the intracranial or skull base cerebral artery is technically feasible, and it can be performed with relatively low risk. From our results, it may be a useful method and effective for long-term survival of patients. But results from a larger number of patients and more long-term follow-up data are still necessary in order to evaluate the safety and usefulness of this method.

  14. ROLE OF ENDOGENOUS CARBON MONOXIDE IN NEOINTIMAL FORMATION INDUCED BY BALLOON-INJURY IN RAT AORTA

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    Objective.The present study investigated the role of endogenous carbon monoxide(CO)in the pathogenesis of neointimal formation induced by balloon injury in rat.Method.Endothelial denudation of the left common carotid artery of rat was carried out by three passages of a Fogarty 2F balloon catheter.DNA,collagen and elastin contents of each intima-media were estimated;and heme oxygenase(HO)activity and CO production in vascular smooth muscle cell(VSMC)were measured after administration of HO inhibitor.Result.Our data showed that neointima occurred in the rat on day 7 and day 21 after balloon injury,and at the same time HO activity and CO production in VSMC were markedly increased.Administration of HO inhibitor,zinc deuteroporphyrin 2,4-bisglycol(ZnDPBG),could effectively inhibit HO activity and CO production,significantly enhance neointimal formation(aortic intima/media ratio were 21.4±1.8% vs 17.6±2.0%,P<0.05 on day 7;and 30.5±2.4% vs 23.0±2.2%,P<0.01 on day 21,respectively,compared with balloon alone group).Conclusion.We concluded that 1)inhibition of CO production may enhance neointimal formation induced by endothelial denudation,implying endogenous CO play an protective role in response to vascular injury,and 2)induction of HO activity may be applied clinically for preventing restenosis after angioplasty.

  15. Cost-effectiveness analysis of paclitaxel-coated balloons for endovascular therapy of femoropopliteal arterial obstructions.

    Science.gov (United States)

    Diehm, Nicolas; Schneider, Henrique

    2013-12-01

    To explore the cost-effectiveness of using drug-eluting balloon (DEB) angioplasty for the treatment of femoropopliteal arterial lesions, which has been shown to significantly lower the rates of target lesion revascularization (TLR) compared with standard balloon angioplasty (BA). A simplified decision-analytic model based on TLR rates reported in the literature was applied to baseline and follow-up costs associated with in-hospital patient treatment during 1 year of follow-up. Costs were expressed in Swiss Francs (sFr) and calculated per 100 patients treated. Budgets were analyzed in the context of current SwissDRG reimbursement figures and calculated from two different perspectives: a general budget on total treatment costs (third-party healthcare payer) as well as a budget focusing on the physician/facility provider perspective. After 1 year, use of DEB was associated with substantially lower total inpatient treatment costs when compared with BA (sFr 861,916 vs. sFr 951,877) despite the need for a greater investment at baseline related to higher prices for DEBs. In the absence of dedicated reimbursement incentives, however, use of DEB was shown to be the financially less favorable treatment approach from the physician/facility provider perspective (12-month total earnings: sFr 179,238 vs. sFr 333,678). Use of DEBs may be cost-effective through prevention of TLR at 1 year of follow-up. The introduction of dedicated financial incentives aimed at improving DEB reimbursements may help lower total healthcare costs.

  16. [Percutaneous transluminal angioplasty in vascular by-passes].

    Science.gov (United States)

    Rodríguez, J E; Fernández Guinea, O; López, V; Suárez Pereiro, M J; Reimunde, E; Cosío, J M; Barreiro, A

    1993-01-01

    Results from 21 cases of percutaneous transluminal angioplasties as a treatment of stenosed vascular by-pass from 16 patients, are presented. The technique took place in 10 cases at the aorto-femoral area, in others 10 cases at the popliteal-femoral area and, in the last one, at the carotid-subclavian area. Preliminary results were successful in all cases (100%). Follow-up showed a better long-term results at the aorto-femoral level. Considering the satisfactory results and also considering that, in case of negative results or re-stenosis, other surgical techniques could be performed, we conclude that the percutaneous transluminal angioplasty should be the first treatment for such of injuries.

  17. Scientific ballooning in India: recent developments

    Science.gov (United States)

    Joshi, M. N.; Damle, S. V.

    The National Scientific Balloon Facility (NBF) of the Tata Institute of Fundamental Research (TIFR) has been conducting regular balloon flights for various experiments in the areas of Space Astronomy and Atmospheric Sciences. A continuous improvement in all aspects of Scientific Ballooning through a sustained R and D programme ensures uptodate services and a better handle on the design specifications for the balloon. Recent developments in balloon grade films, continuous improvements in design specifications, balloon manufacturing methods, flight operational procedures and improved balloon flight capabilities have resulted in a greatly improved flight performance in the last five years. A launch capability upgradation programme in terms of new launch spool and new launch vehicle has been initiated to be able to safely launch balloons with gross lifts upto 3500 kg, balloon volumes upto 450,000 m^3 and payloads upto 1400 kg. A series of steps have been initiated to improve long duration flight capabilities. In this paper, we present details on some of these aspects of Scientific Ballooning in India.

  18. Resource utilization, cost, and health status impacts of coronary stent versus "optimal" percutaneous coronary angioplasty: results from the OPUS-I trial.

    Science.gov (United States)

    Neil, Nancy; Ramsey, Scott D; Cohen, David J; Every, Nathan R; Spertus, John A; Weaver, W Douglas

    2002-08-01

    In the OPUS-I trial, primary coronary stent implantation reduced 6-month composite incidence of death, myocardial infarction, cardiac surgery, or target vessel revascularization relative to a strategy of initial PTCA with provisional stenting in patients undergoing single vessel coronary angioplasty. The purpose of this research was to compare the economic and health status impacts of each treatment strategy. Resource utilization data were collected for the 479 patients randomized in OPUS-I. Itemized cost estimates were derived from primary hospital charge data gathered in previous multicenter trials evaluating coronary stents, and adjusted to approximate 1997 Medicare-based costs for a cardiac population. Health status at 6 months was assessed using the Seattle Angina Questionnaire (SAQ). Initial procedure related costs for patients treated with a primary stent strategy were higher than those treated with optimal PTCA/provisional stent ($5,389 vs $4,339, P < 0.001). Costs of initial hospitalization were also higher for patients in the primary stent group ($9,234 vs $8,434, P < 0.01) chiefly because of the cost differences in the index revascularization. Mean 6-month costs were similar in the two groups; however, there was a slight cost advantage associated with primary stenting. Bootstrap replication of 6-month cost data sustained the economic attractiveness of the primary stent strategy. There were no differences in SAQ scores between treatment groups. In patients undergoing single vessel coronary angioplasty, routine stent implantation improves important clinical outcomes at comparable, or even reduced cost, compared to a strategy of initial balloon angioplasty with provisional stenting.

  19. Below knee angioplasty in elderly patients: Predictors of major adverse clinical outcomes.

    LENUS (Irish Health Repository)

    Keeling, Aoife N

    2011-03-01

    To determine predictors of clinical outcome following percutaneous transluminal angioplasty (PTA) in elderly patients with below knee atherosclerotic lesions causing intermittent claudication (IC) or critical limb ischaemia (CLI).

  20. Basic study of effects on the smooth muscle cells' proliferation with novel short-term thermal angioplasty in vitro and in vivo

    Science.gov (United States)

    Kunio, M.; Shimazaki, N.; Ito, A.; Hayashi, T.; Arai, T.; Sakurada, M.

    2011-03-01

    We investigated the effect on smooth muscle cells' proliferation with stretch-fixing in both in vitro and in vivo porcine study to determine the optimum heat condition of novel short-term thermal angioplasty, Photo-thermo Dynamic Balloon Angioplasty (PTDBA). With PTDBA, we have obtained the sufficient arterial dilatation by short-term heating (< 15 s, < 70 °C) and low dilatation pressure (< 0.4 MPa) without excessive neo-intimal hyperplasia on chronic phase. The smooth muscle cells were found to be fixed with stretched shape in vascular wall after PTDBA in vivo. The deformation rate of smooth muscle cells' nuclei was 1.6 +/- 0.1 after PTDBA (15 s, 65 °C, 0.35 MPa). The smooth muscle cells, which were extracted from porcine arteries, were cultured on the specially designed equipment to give stretch-fixing stimulus in vitro. The cell proliferation was inhibited at 20 % stretching compared to 15 % stretching significantly (p < 0.05). The immunostaining specimens of basic Fibroblast Growth Factor (bFGF) and its receptor FGFR-1 were made from the porcine arteries in vivo. We found that the expressions of bFGF and FGFR-1 in the media were not observed after PTDBA. We think that these results suggested the possibility for the inhibition of the excessive cell proliferation after PTDBA.

  1. Early Results with the Use of Heparin-bonded Stent Graft to Rescue Failed Angioplasty of Chronic Femoropopliteal Occlusive Lesions: TASC D Lesions Have a Poor Outcome

    Energy Technology Data Exchange (ETDEWEB)

    Kuhan, Ganesh, E-mail: gkuhan@nhs.net; Abisi, Said; Braithwaite, Bruce D.; MacSweeney, Shane T. R. [Nottingham University Hospitals, Vascular and Endovascular Unit, Queens Medical Centre (United Kingdom); Whitaker, Simon C.; Habib, Said B. [Nottingham University Hospitals, Department of Radiology, Queen' s Medical Centre (United Kingdom)

    2012-10-15

    Purpose: To evaluate early patency rate of the heparin-bonded stent grafts in atherosclerotic long femoropopliteal occlusive disease, and to identify factors that affect outcome. Methods: Heparin-bonded Viabahn stent grafts were placed in 33 limbs in 33 patients during 2009-2010. The stents were deployed to rescue failed conventional balloon angioplasty. Mean age was 69 (range 44-88) years, and 67 % (22 of 33) were men. Most procedures (21 of 33, 64 %) were performed for critical limb ischemia (33 % for rest pain, 30 % tissue loss). Kaplan-Meier plots and Cox regression analysis were used to identify significant risk factors. Results: The average length of lesions treated was 25 {+-} 10 cm, and they were predominantly TASC (Transatlantic Intersociety Consensus) D (n = 13) and C (n = 17) lesions. The median primary patency was 5.0 months (95 % confidence interval 1.22-8.77). The mean secondary patency was 8.6 months (95 % confidence interval 6.82-10.42). Subsequently, 4 patients underwent bypass surgery and 5 patients underwent major amputation. One patient died. There were 5 in-stent or edge-stent stenoses. Cox multivariate regression analysis identified TASC D lesions to be a significant risk factor for early occlusion (p = 0.035). Conclusion: TASC D lesions of femoropopliteal occlusions have poor patency rates with the use of heparin-bonded stent grafts after failed conventional angioplasty. Alternative options should be considered for these patients.

  2. Viscoelastic behaviour of pumpkin balloons

    Science.gov (United States)

    Gerngross, T.; Xu, Y.; Pellegrino, S.

    2008-11-01

    The lobes of the NASA ULDB pumpkin-shaped super-pressure balloons are made of a thin polymeric film that shows considerable time-dependent behaviour. A nonlinear viscoelastic model based on experimental measurements has been recently established for this film. This paper presents a simulation of the viscoelastic behaviour of ULDB balloons with the finite element software ABAQUS. First, the standard viscoelastic modelling capabilities available in ABAQUS are examined, but are found of limited accuracy even for the case of simple uniaxial creep tests on ULDB films. Then, a nonlinear viscoelastic constitutive model is implemented by means of a user-defined subroutine. This approach is verified by means of biaxial creep experiments on pressurized cylinders and is found to be accurate provided that the film anisotropy is also included in the model. A preliminary set of predictions for a single lobe of a ULDB is presented at the end of the paper. It indicates that time-dependent effects in a balloon structure can lead to significant stress redistribution and large increases in the transverse strains in the lobes.

  3. Study of the stenosis-inhibiting effects of high-dose rate endovascular irradiation in balloon injured rabbit iliac artery

    Energy Technology Data Exchange (ETDEWEB)

    Kobayashi, Masao; Sekine, Hiroshi; Suzuki, Akihiko; Ohyama, Noriaki; Hataba, Yoshiaki [Jikei Univ., Tokyo (Japan). School of Medicine

    2002-12-01

    With scanning electron microscopy, we investigated the effectiveness of inhibition by endovascular irradiation (Ir-192 high dose rate) of intimal hyperplasia after angioplasty. We also examined changes in the irradiated arterial vessel wall after balloon injury and the mechanism of the inhibition of intimal hyperplasia. Japanese white rabbits (male, 3.0-3.5 kg) were used. Under anesthesia, a percutaneous transluminal angioplasty balloon catheter was inserted into the iliac arteries and inflated to 6 atm for 1 minute 3 times at 1-minute intervals. One artery was irradiated (12 Gy) with an iridium-192 high-dose rate endovascular irradiation device (the reference point was set at 2 mm to center; dose rate 18-48 Gy/min). From 2 days to 12 weeks after the procedure, fixation was performed at a perfusion pressure of 120 to 150 cm H{sub 2}O, and the arteries were systematically examined. Endothelial cells after balloon injury with or without irradiation were examined with light microscopy or scanning electron microscopy. Endovascular irradiation inhibited intimal hyperplasia for at least 12 weeks. Irradiated arteries were not constricted, so we assumed that this phenomenon was caused by inhibition of negative remodeling. From 1 to 2 weeks after the procedure, we recognized mild intimal hyperplasia at nonirradiated arteries, but no hyperplasia recognized at irradiated arteries. This hyperplasia was mainly constituted by endothelial cells, and this change happened at least 2 days with scanning electron scopy. At the injury site, platelet aggregation, thrombus, and endothelial cells were observed. After irradiation, endothelial cells and nuclei were injured. Hypertrophic nuclei, the deformity of cell alignment, and stratified endothelial cells were recognized. It means that irradiation may affect the metabolism of the endothelial cells against normal formation with light microscopy. (author)

  4. An experimental and kinetic modeling study of premixed nitroethane flames at low pressure

    DEFF Research Database (Denmark)

    Zhang, Kuiwen; Zhang, Lidong; Xie, Mingfeng

    2013-01-01

    An experimental and kinetic modeling study is reported on three premixed nitroethane/oxygen/argon flames at low pressure (4.655kPa) with the equivalence ratios (Φ) of 1.0, 1.5 and 2.0. Over 30 flame species were identified with tunable synchrotron vacuum ultraviolet photoionization mass spectrome......An experimental and kinetic modeling study is reported on three premixed nitroethane/oxygen/argon flames at low pressure (4.655kPa) with the equivalence ratios (Φ) of 1.0, 1.5 and 2.0. Over 30 flame species were identified with tunable synchrotron vacuum ultraviolet photoionization mass...... predictions have shown satisfactory agreement with the experimental results. Basing on the rate-of-production analysis, the reaction pathways that feature the combustion of nitroethane were revealed, including the primary decomposition of C–N bond fission, the oxidation of C2 and C1 hydrocarbons...

  5. A comparison among optical emission spectroscopic methods of determining electron temperature in low pressure argon plasmas

    Institute of Scientific and Technical Information of China (English)

    Niu Tian-Ye; Cao Jin-Xiang; Liu Lei; Liu Jin-Ying; Wang Yan; Wang Liang

    2007-01-01

    In this article, four kinds of optical emission spectroscopic methods of determining electron temperature are used to investigate the relationship between electron temperature and pressure in the cylindrical plasmas of dc glow discharges at low pressures in laboratory by measuring the relative intensities of ArI lines at various pressures. These methods are developed respectively on the basis of the Fermi-Dirac model, corona model, and two kinds of electron collision cross section models according to the kinetic analysis. Their theoretical bases and the conditions to which they are applicable are reviewed, and their calculation results and fitting errors are compared with each other. The investigation has indicated that the electron temperatures obtained by the four methods become consistent with each other when the pressure increases in the low pressure argon plasmas.

  6. Finite Element Modeling and Analysis of Powder Stream in Low Pressure Cold Spray Process

    Science.gov (United States)

    Goyal, Tarun; Walia, Ravinderjit Singh; Sharma, Prince; Sidhu, Tejinder Singh

    2016-07-01

    Low pressure cold gas dynamic spray (LPCGDS) is a coating process that utilize low pressure gas (5-10 bars instead of 25-30 bars) and the radial injection of powder instead of axial injection with the particle range (1-50 μm). In the LPCGDS process, pressurized compressed gas is accelerated to the critical velocity, which depends on length of the divergent section of nozzle, the propellant gas and particle characteristics, and the diameters ratio of the inlet and outer diameters. This paper presents finite element modeling (FEM) of powder stream in supersonic nozzle wherein adiabatic gas flow and expansion of gas occurs in uniform manner and the same is used to evaluate the resultant temperature and velocity contours during coating process. FEM analyses were performed using commercial finite volume package, ANSYS CFD FLUENT. The results are helpful to predict the characteristics of powder stream at the exit of the supersonic nozzle.

  7. Shock tube study of n-decane ignition at low pressures

    Institute of Scientific and Technical Information of China (English)

    Xiao-Fei Nie; Ping Li; Chang-Hua Zhang; Wei Xie; Cong-Shan Li; Xiang-Yuan Li

    2012-01-01

    Ignition delay times for n-decane/O2/Ar mixtures were measured behind reflected shock waves using endwall pressure and CH* emission measurements in a heated shock tube.The initial postshock conditions cover pressures of 0.09-0.26 MPa,temperatures of 1 227-1 536 K,and oxygen mole fractions of 3.9%-20.7% with an equivalence ratio of 1.0.The correlation formula of ignition delay dependence on pressure,temperature,and oxygen mole fraction was obtained.The current data are in good agreement with available low-pressure experimental data,and they are then compared with the prediction of a kinetic mechanism.The current measurements extend the kinetic modeling targets for the n-decane combustion at low pressures.

  8. Kinetic analysis of negative power deposition in inductive low pressure plasmas

    Science.gov (United States)

    Trieschmann, Jan; Mussenbrock, Thomas

    2017-02-01

    Negative power deposition in low pressure inductively coupled plasmas (ICPs) is investigated by means of an analytical model which couples Boltzmann’s equation and the quasi-stationary Maxwell’s equations. Exploiting standard Hilbert space methods an explicit solution for both, the electric field and the distribution function of the electrons for a bounded discharge configuration subject to an unsymmetrical excitation is found for the first time. The model is applied to a low pressure ICP discharge. In this context particularly the anomalous skin effect and the effect of phase mixing is discussed. The analytical solution is compared with results from electromagnetic full wave particle in cell simulations. Excellent agreement between the analytical and the numerical results is found.

  9. Surface energy-tunable iso decyl acrylate based molds for low pressure-nanoimprint lithography

    Science.gov (United States)

    Tak, Hyowon; Tahk, Dongha; Jeong, Chanho; Lee, Sori; Kim, Tae-il

    2017-10-01

    We presented surface energy-tunable nanoscale molds for unconventional lithography. The mold is highly robust, transparent, has a minimized haze, does not contain additives, and is a non-fluorinated isodecyl acrylate and trimethylolpropane triacrylate based polymer. By changing the mixing ratio of the polymer components, the cross-linking density, mechanical modulus, and surface energy (crucial factors in low pressure ((1–2) × 105 N m‑2) low pressure-nanoimprint lithography (LP-NIL)), can be controlled. To verify these properties of the molds, we also characterized the surface energy by measuring the contact angles and calculating the work of adhesion among the wafer, polymer film, and mold for successful demolding in nanoscale structures. Moreover, the molds showed high optical clarity and precisely tunable mechanical and surface properties, capable of replicating sub-100 nm patterns by thermal LP-NIL and UV-NIL.

  10. Interplay between lattice dynamics and the low-pressure phase of simple cubic polonium

    Science.gov (United States)

    Zaoui, A.; Belabbes, A.; Ahuja, R.; Ferhat, M.

    2011-04-01

    Low-pressure structural properties of simple cubic polonium are explored through first-principles density-functional theory based relativistic total energy calculations using pseudopotentials and plane-wave basis set, as well as linear-response theory. We have found that Po undergoes structural phase transition at low pressure near 2 GPa, where the element transforms from simple cubic to a mixture of two trigonal phases namely, hR1 (α=86°) and hR2 (α=97.9°) structures. The lattice dynamics calculations provide strong support for the observed phase transition, and show the dynamical stability (instability) of the hR2 (hR1) phase.

  11. Mesoscopic simulation of diffusive contaminant spreading in gas flows at low pressure

    CERN Document Server

    Schmieschek, S; Keller, F; Nieken, U; Harting, J

    2015-01-01

    Many modern production and measurement facilities incorporate multiphase systems at low pressures. In this region of flows at small, non-zero Knudsen- and low Mach numbers the classical mesoscopic Monte Carlo methods become increasingly numerically costly. To increase the numerical efficiency of simulations hybrid models are promising. In this contribution, we propose a novel efficient simulation approach for the simulation of two phase flows with a large concentration imbalance in a low pressure environment in the low intermediate Knudsen regime. Our hybrid model comprises a lattice-Boltzmann method corrected for the lower intermediate Kn regime proposed by Zhang et al. for the simulation of an ambient flow field. A coupled event-driven Monte-Carlo-style Boltzmann solver is employed to describe particles of a second species of low concentration. In order to evaluate the model, standard diffusivity and diffusion advection systems are considered.

  12. Development of a low pressure chromatographic flow system for monitoring the biodegradation of ofloxacin and ciprofloxacin

    OpenAIRE

    Santos, Inês C.; Mesquita, Raquel R. B.; Amorim, Catarina L.; Castro, Paula M. L.; Rangel,António O. S. S.

    2016-01-01

    In this work, we propose a simple low pressure chromatography method with a high throughput for monitoring the biodegradation of fluoroquinolones. Fluoroquinolones are a class of antibiotics that have been accumulating in the environment as a consequence of their release from different sources, namely hospital waste. It has been found that wastewater treatment plants are not able to completely remove this type of micro-pollutants and so, alternative solutions are necessary. Some biodegradatio...

  13. Experimental Studies of Low-Pressure Plasma Jet by Means of Langmuir Probes and Emission Spectra

    Institute of Scientific and Technical Information of China (English)

    LIU Lei; CAO Jinxiang; NIU Tianye; WANG Liang; MENG Gang; LIU Xin; YUAN Lei; WU Runhui; ZHANG Shengjun; REN Aimin

    2009-01-01

    An investigation was made into the argon plasma jet that expanded in a low-pressure vacuum chamber. The spatial distributions of the parameters of the plasma jet with different supplied powers were measured using a ten-channel Langmuir probe array. The chemical species in the plasma jet were identified by emission spectroscopy. The electron excitation temperatures at two positions, 10 cm and 50 cm downstream from the nozzle exit were calculated, respectively, by the Boltzmann plot method.

  14. Low-pressure glow discharge in a Xenon/Chlorine mixture

    Science.gov (United States)

    Shuaibov, A. K.; Shimon, L. L.; Shevera, I. V.; Dashchenko, A. I.

    2002-12-01

    The spatial, electrical, and optical characteristics of a transverse glow discharge and a volume discharge with a spherical anode and plane cathode in low-pressure Xe/Cl2 mixtures are studied. It is shown that the transverse glow discharge in mixtures with a low chlorine content occupies most of the interelectrode gap and exists in the form of strata. As the total pressure ( P≥300 Pa) and the partial chlorine pressure ( P(Cl2)≥80 Pa) increase, a solitary plasma domain with a volume of 1-2 cm3 forms in the discharge gap. It acts as a selective source of UV radiation in the XeCl(D-X) 236-nm, Cl2 (D'-A') 257-nm, and XeCl(B-X) 308-nm bands. In certain Xe/Cl2 mixtures, plasma self-oscillations in the frequency range 1-100 kHz are observed. The current of a low-pressure volume discharge with a spherical anode and plane cathode and the emission from it have both a dc and an ac component. The pressure and composition of the working mixture, as well as the average current of the volume discharge are optimized to attain the maximum emission intensity of the XeCl(D,B-X) bands. Low-pressure volume discharges in xenon/chlorine mixtures can be used as active media in low-pressure large-aperture planar or cylindrical excimer-halogen lamps emitting modulated or repetitive pulsed UV radiation.

  15. Observation of Quartz Cathode-Luminescence in a Low Pressure Plasma Discharge

    Science.gov (United States)

    Foster, John E.

    2004-01-01

    Intense, steady-state cathode-luminescence has been observed from exposure of quartz powder to a low pressure rf-excited argon plasma discharge. The emission spectra (400 to 850 nm) associated with the powder luminescence were documented as a function of bias voltage using a spectrometer. The emission was broad-band, essentially washing out the line spectra features of the argon plasma discharge.

  16. Low-pressure pneumoperitoneum during laparoscopic donor nephrectomy to optimize live donors' comfort.

    Science.gov (United States)

    Warlé, M C; Berkers, A W; Langenhuijsen, J F; van der Jagt, M F; Dooper, Ph M; Kloke, H J; Pilzecker, D; Renes, S H; Wever, K E; Hoitsma, A J; van der Vliet, J A; D'Ancona, F C H

    2013-01-01

    Nowadays, laparoscopic donor nephrectomy (LDN) has become the gold standard to procure live donor kidneys. As the relationship between donor and recipient loosens, it becomes of even greater importance to optimize safety and comfort of the surgical procedure. Low-pressure pneumoperitoneum has been shown to reduce pain scores after laparoscopic cholecystectomy. Live kidney donors may also benefit from the use of low pressure during LDN. To evaluate feasibility and efficacy to reduce post-operative pain, we performed a randomized blinded study. Twenty donors were randomly assigned to standard (14 mmHg) or low (7 mmHg) pressure during LDN. One conversion from low to standard pressure was indicated by protocol due to lack of progression. Intention-to-treat analysis showed that low pressure resulted in a significantly longer skin-to-skin time (149 ± 86 vs. 111 ± 19 min), higher urine output during pneumoperitoneum (23 ± 35 vs. 11 ± 20 mL/h), lower cumulative overall pain score after 72 h (9.4 ± 3.2 vs. 13.5 ± 4.5), lower deep intra-abdominal pain score (11 ± 3.3 vs. 7.5 ± 3.1), and a lower cumulative overall referred pain score (1.8 ± 1.9 vs. 4.2 ± 3). Donor serum creatinine levels, complications, and quality of life dimensions were not significantly different. Our data show that low-pressure pneumoperitoneum during LDN is feasible and may contribute to increase live donors' comfort during the early post-operative phase.

  17. Low pressure arc discharge lamp apparatus with magnetic field generating means

    Science.gov (United States)

    Grossman, M.W.; George, W.A.; Maya, J.

    1987-10-06

    A low-pressure arc discharge apparatus having a magnetic field generating means for increasing the output of a discharge lamp is disclosed. The magnetic field generating means, which in one embodiment includes a plurality of permanent magnets, is disposed along the lamp for applying a constant transverse magnetic field over at least a portion of the positive discharge column produced in the arc discharge lamp operating at an ambient temperature greater than about 25 C. 3 figs.

  18. Solid oxide fuel cell electrolytes produced via very low pressure suspension plasma spray and electrophoretic deposition

    OpenAIRE

    Fleetwood, James D

    2014-01-01

    Solid oxide fuel cells (SOFCs) are a promising element of comprehensive energy policies due to their direct mechanism for converting the oxidization of fuel, such as hydrogen, into electrical energy. Both very low pressure plasma spray and electrophoretic deposition allow working with high melting temperature SOFC suspension based feedstock on complex surfaces, such as in non-planar SOFC designs. Dense, thin electrolytes of ideal composition for SOFCs can be fabricated with each of these proc...

  19. Growth Enhancement of Radish Sprouts Induced by Low Pressure O2 Radio Frequency Discharge Plasma Irradiation

    Science.gov (United States)

    Kitazaki, Satoshi; Koga, Kazunori; Shiratani, Masaharu; Hayashi, Nobuya

    2012-01-01

    We studied growth enhancement of radish sprouts (Raphanus sativus L.) induced by low pressure O2 radio frequency (RF) discharge plasma irradiation. The average length of radish sprouts cultivated for 7 days after O2 plasma irradiation is 30-60% greater than that without irradiation. O2 plasma irradiation does not affect seed germination. The experimental results reveal that oxygen related radicals strongly enhance growth, whereas ions and photons do not.

  20. Optimization Design and Experimental Study of Low-Pressure Axial Fan with Forward-Skewed Blades

    OpenAIRE

    2007-01-01

    This paper presents an experimental study of the optimization of blade skew in low pressure axial fan. Using back propagation (BP) neural network and genetic algorithm (GA), the optimization was performed for a radial blade. An optimized blade is obtained through blade forward skew. Measurement of the two blades was carried out in aerodynamic and aeroacoustic performance. Compared to the radial blade, the optimized blade demonstrated improvements in efficiency, total pres...

  1. Study of the low-pressure plasma effect on polypropylene nonwovens

    Science.gov (United States)

    López, R.; Boronat, T.; Pascual, M.; Calvo, O.; Balart, R.

    2010-06-01

    In this work we have used low-pressure plasma with a gas based on methane and oxygen mixture to improve wettability and durability of a PP nonwoven fabrics. The obtained results show good durability with the use of methane-oxygen plasma mixture gas. The effects of the plasma are similar to a plasmapolymerization process but in this case we obtain hydrophilic properties with high durability. The surface does not suffer important changes and the roughness of the material remains constant.

  2. Effect of balanced low pressure drying of curcuma longa leaf on skin immune activation activities.

    Science.gov (United States)

    Choi, Wooseok; Lim, Hye Won; Lee, Hyeon Yong

    2014-01-01

    The effect of balanced low pressure drying pretreatment associated with ultrasonication extraction (BU) on the enhancement of skin immune modulatory activities of Curcuma longa leaf was studied by comparing with conventional hot air drying (HE), freeze drying (FE) and balanced low pressure drying (BE) pretreatment processes. In considering skin immune activation activities such as the inhibition of hyaluronidase activity, the BU extract showed ca. 10% higher than those of HE, and even higher than that of the FE extract. Nitric oxide production from macrophage of the BU extract in adding 1.0 mg/mL was increased up to 16.5 μM. When measuring inhibition of IL-6 and TNF-a production from the human T lymphocytes (T cell), the BU extract also showed 53% and 78% of inhibition effect, respectively. It is found that the BU extract could effectively suppress the expression levels of skin inflammation related genes such as Cox-2 and iNOS, down to 80% and 85% compared to the control, respectively. Balanced low pressure drying process was especially active on dehydration of the leaves with minimizing the destruction and making easier elution of the bioactive substances, which resulted in higher extraction yield and better biological activities.

  3. Characteristics of long-gap AC streamer discharges under low pressure conditions

    Science.gov (United States)

    Yang, Yaqi; Li, Weiguo; Xia, Yu; Yuan, Chuangye

    2017-10-01

    The generation and propagation of a streamer is a significant physical process of air gap discharge. Research on the mechanism of streamers under low-pressure conditions is helpful for understanding the process of long-gap discharge in a high-altitude area. This paper describes laboratory investigations of streamer discharge under alternating current (AC) voltage in a low pressure test platform for a 60 cm rod-plane gap at 30 kPa, and analyzes the characteristics of streamer generation and propagation. The results show that the partial streamer and breakdown streamer all occur in the positive half-cycle of AC voltage near the peak voltage at 30 kPa. The partial streamer could cause the distortion of current and voltage waveform, and it appears as the branching characteristic at the initial stage. With the extension of the streamer, the branching and tortuosity phenomena become gradually obvious, but the branching is suppressed when the streamer crosses the gap. The low-pressure condition has little influence on the tortuosity length and the tortuosity number of the streamer, but affect the diameter of streamer obviously.

  4. Efficacy of epidural blood patches for spontaneous low-pressure headaches: a case series.

    Science.gov (United States)

    Ansel, S; Rae, A; Tyagi, A

    2016-12-01

    Patients with a spontaneous cerebrospinal fluid leak, normally at a spinal level, typically present with low-pressure headache. In refractory cases, an epidural blood patch may be attempted. We aimed to assess the efficacy of lumbar epidural blood patching in spontaneous, low-pressure headaches. Methods We retrospectively analysed notes of patients who had an epidural blood patch performed for spontaneous low-pressure headaches in a single centre. Information regarding demographics, radiology and clinic follow-up was extracted from an electronic patient record system. Questionnaires regarding outcome were sent to patients a minimum of 6 months post-procedure. All patients received an epidural blood patch in the lumbar region irrespective of the site of cerebrospinal fluid leak. Results Sixteen patients who underwent lumbar epidural blood patching were analysed (11 female; mean age 43 years). The site of cerebrospinal fluid leak was evident in only 3/16 patients. Thirteen patients attended clinic follow-up; three reported complete headache resolution, four reported improvement in intensity or frequency and six described no change. Five of eight questionnaire respondents reported reduction in pain, and in these responders, mean headache severity improved from 9/10 to 3/10. Five of eight patients returning follow-up questionnaires reported sustained improvement in headache symptoms. Conclusion Epidural blood patch procedures can provide sustained improvement in headache symptoms in selected patients with spontaneous intracranial hypotension, but an untargeted approach has a lower success rate than reported in other case series.

  5. Endovascular brachytherapy (EVBT) with rhenium-188 for restenosis prophylaxis after angioplasty of infrainguinal lesions. Early experience; Endovaskulaere Brachytherapie (EVBT) mit Rhenium-188 zur Restenoseprophylaxe nach Angioplastie infrainguinaler Laesionen. Erste Erfahrungen

    Energy Technology Data Exchange (ETDEWEB)

    Leissner, G.G.; Winterstein, A.; Bohndorf, K.; Wohlgemuth, W.A. [Klinikum Augsburg (Germany). Klinik fuer Diagnostische Radiologie und Neuroradiologie; Wengenmair, H. [Klinikum Augsburg (Germany). Medizinische Physik und Strahlenschutz; Sciuk, J. [Klinikum Augsburg (Germany). Klinik fuer Nuklearmedizin; Woelfle, K.D. [Klinikum Augsburg (Germany). Klinik fuer Gefaesschirurgie; Weinrich, K. [Klinikum Augsburg (Germany). II. Medizinische Klinik, Angiologie

    2011-08-15

    Purpose: Restenosis remains a major problem in percutaneous transluminal angioplasty (PTA) of peripheral arteries. The aim of this feasibility study was to evaluate the technical feasibility and safety of a new endovascular brachytherapy (EVBT) device with Rhenium-188 in restenosis prophylaxis of infrainguinal arteries. Materials and Methods: From March 2006 to April 2009, 52 patients with 71 infrainguinal arterial lesions were treated with Re-188 to prevent restenosis after PTA. 40 patients with 53 lesions (24 de-novo lesions and 29 restenoses) were reexamined (clinic, color-coded duplex ultrasound) after a mean follow-up period of 12.7 months (2.6 to 25.1 months). The liquid beta-emitter Re-188 was introduced to the target lesion via an EVBT certified PTA balloon and a tungsten applicator. After the calculated irradiation time, Re-188 was aspirated back into the tungsten applicator. A dose of 13 Gy was applied at a depth of 2 mm into the vessel wall. Results: After a mean follow-up of 12.7 months, the overall restenosis rate after Re-PTA was 15.1 % (8/53 lesions). The restenosis rate for de-novo lesions was 20.8 % (5/24) and 10.3 % for restenoses (3/29). In 4 patients reintervention was necessary (3 PTAs and 2 major amputations). No periprocedural complications were observed. No elevated radiation dose for the patient or the interventionalist was measured. Conclusion: EVBT with a Re-188 filled balloon catheter was technically feasible and safe after PTA of infrainguinal arterial lesions with restenosis rates lower than expected compared to published results. Treatment of restenoses seems to be more effective than de-novo lesions. (orig.)

  6. Hyperspectral Polarimeter for Monitoring Balloon Strain Project

    Data.gov (United States)

    National Aeronautics and Space Administration — NASA's latest generation of superpressure, ultra long duration balloons (ULDB) extend the flight time for stratospheric experiments to levels previously unattainable...

  7. Scientific Ballooning Activities and Recent Developments in Technology and Instrumentation of the TIFR Balloon Facility, Hyderabad

    Science.gov (United States)

    Buduru, Suneel Kumar

    2016-07-01

    The Balloon Facility of Tata Institute of Fundamental Research (TIFR-BF) is a unique center of expertise working throughout the year to design, fabricate and launch scientific balloons mainly for space astronomy, atmospheric science and engineering experiments. Recently TIFR-BF extended its support to new user scientists for conducting balloon launches for biological and middle atmospheric sciences. For the first time two balloon launches conducted for sending live lab rats to upper stratosphere and provided launch support for different balloon campaigns such as Tropical Tropopause Dynamics (TTD) to study water vapour content in upper tropospheric and lower stratospheric regions over Hyderabad and the other balloon campaign to study the Asian Tropopause Aerosol Layer (BATAL) during the Indian summer monsoon season. BATAL is the first campaign to conduct balloon launches during active (South-West) monsoon season using zero pressure balloons of different volumes. TIFR-BF also provided zero pressure and sounding balloon support to various research institutes and organizations in India and for several international space projects. In this paper, we present details on our increased capability of balloon fabrication for carrying heavier payloads, development of high strength balloon load tapes and recent developments of flight control and safety systems. A summary of the various flights conducted in two years will be presented along with the future ballooning plans.

  8. Molecular-level Insight into Unusual Low Pressure CO2 Affinity in Pillared Metal-Organic Frameworks

    NARCIS (Netherlands)

    Burtch, N.C.; Jasuja, H.; Dubbeldam, D.; Walton, K.S.

    2013-01-01

    Fundamental insight into how low pressure adsorption properties are affected by chemical functionalization is critical to the development of next-generation porous materials for postcombustion CO2 capture. In this work, we present a systematic approach to understanding low pressure CO2 affinity in i

  9. Molecular-level Insight into Unusual Low Pressure CO2 Affinity in Pillared Metal-Organic Frameworks

    NARCIS (Netherlands)

    Burtch, N.C.; Jasuja, H.; Dubbeldam, D.; Walton, K.S.

    2013-01-01

    Fundamental insight into how low pressure adsorption properties are affected by chemical functionalization is critical to the development of next-generation porous materials for postcombustion CO2 capture. In this work, we present a systematic approach to understanding low pressure CO2 affinity in i

  10. Reduction of Intimal Hyperplasia in Injured Rat Arteries Promoted by Catheter Balloons Coated with Polyelectrolyte Multilayers that Contain Plasmid DNA Encoding PKCδ

    Science.gov (United States)

    Bechler, Shane L.; Si, Yi; Yu, Yan; Ren, Jun; Liu, Bo; Lynn, David M.

    2012-01-01

    New therapeutic approaches that eliminate or reduce the occurrence of intimal hyperplasia following balloon angioplasty could improve the efficacy of vascular interventions and improve the quality of life of patients suffering from vascular diseases. Here, we report that treatment of arteries using catheter balloons coated with thin polyelectrolyte-based films (‘polyelectrolyte multilayers’, PEMs) can substantially reduce intimal hyperplasia in an in vivo rat model of vascular injury. We used a layer-by-layer (LbL) process to coat the surfaces of inflatable catheter balloons with PEMs composed of nanolayers of a cationic poly(β-amino ester) (polymer 1) and plasmid DNA (pPKCδ) encoding the δ isoform of protein kinase C (PKCδ), a regulator of apoptosis and other cell processes that has been demonstrated to reduce intimal hyperplasia in injured arterial tissue when administered via perfusion using viral vectors. Insertion of balloons coated with polymer 1/pPKCδ multilayers into injured arteries for 20 min resulted in local transfer of DNA and elevated levels of PKCδ expression in the media of treated tissue 3 days after delivery. IFC and IHC analysis revealed these levels of expression to promote downstream cellular processes associated with up-regulation of apoptosis. Analysis of arterial tissue 14 days after treatment revealed polymer 1/pPKCδ-coated balloons to reduce the occurrence of intimal hyperplasia by ~60% compared to balloons coated with films containing empty plasmid vectors. Our results demonstrate the potential therapeutic value of this nanotechnology-based approach to local gene delivery in the clinically important context of balloon-mediated vascular interventions. These PEM-based methods could also prove useful for other in vivo applications that require short-term, surface-mediated transfer of plasmid DNA. PMID:23069712

  11. Angioplasty alone versus angioplasty and stenting for subclavian artery stenosis--a systematic review and meta-analysis.

    Science.gov (United States)

    Chatterjee, Saurav; Nerella, Nishant; Chakravarty, Saneka; Shani, Jacob

    2013-01-01

    Subclavian artery stenosis has long been treated with great success with bypass surgery. Percutaneous intervention, often used in combination with stent placement, has come into vogue for the past few years as a safe and effective therapeutic modality. This study aimed to compare angioplasty alone with angioplasty followed by stent placement by combining available data. The objective of this study was to perform a review of the available literature to compare the efficacy of percutaneous transluminal angioplasty (PTA) alone with PTA followed by stent placement for proximal subclavian artery stenosis. Successful recanalization was defined as patency at the end of 1 year, and reocclusions and restenoses were noted as events for the purpose of pooling the data. The authors searched the Specialized Register and the Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library, PubMed, EMBASE, and CINAHL databases for relevant trials/studies comparing PTA and PTA with stenting. Review authors independently assessed the methodological quality of studies (focusing on the adequacy of the randomization process, allocation concealment, blinding, completeness of follow-up, and intention-to-treat analysis) and selected studies for inclusion. All retrospective observational studies were also included in the analysis in the absence of double-blinded randomized trials for increasing sample size. All analyses were done using RevMan 5.0. Odds ratio was calculated using Mantel-Haenszel test with a fixed effect model. All included studies were assessed by all authors for potential sources of bias. Eight studies were included in the analysis having 544 participants. Stenting after PTA was significantly superior to angioplasty alone for treatment of subclavian artery stenosis and maintenance of patency at 1 year, as indicated by absence of events (P = 0.004; 95% confidence interval, odds ratio 2.37 [1.32-4.26]) without significant complication rates for either

  12. BAlloon versus Stenting in severe Ischaemia of the Leg-3 (BASIL-3): study protocol for a randomised controlled trial.

    Science.gov (United States)

    Hunt, Benjamin D; Popplewell, Matthew A; Davies, Huw; Meecham, Lewis; Jarrett, Hugh; Bate, Gareth; Grant, Margaret; Patel, Smitaa; Hewitt, Catherine; Andronis, Lazaros; Deeks, Jonathan J; Bradbury, Andrew

    2017-05-19

    Severe limb ischaemia (SLI) is defined as the presence of rest pain and/or tissue loss secondary to lower extremity atherosclerotic peripheral arterial disease. The superficial femoral and popliteal arteries are the most commonly diseased vessels in such patients and are being increasingly treated using endovascular revascularisation techniques. However, it is currently unknown whether drug-eluting stents and drug-coated balloons confer additional clinical benefits over more established techniques using plain balloons and bare metal stents, or whether they represent a cost-effective use of NHS resources. The BASIL-3 trial is a UK National Institute for Health Research, Health Technology Assessment Programme-funded, multicentre, randomised controlled trial (RCT) comparing the clinical and cost-effectiveness of plain balloon angioplasty with or without bail-out bare metal stenting, drug-coated balloon angioplasty with or without bail-out bare metal stenting, and primary stenting with drug-eluting stents for SLI secondary to femoro-popliteal disease. Patients with 'multilevel' disease may receive aorto-iliac and/or infrapopliteal treatments concurrently with their randomised femoro-popliteal intervention. The primary clinical outcome is amputation-free survival defined as the time to major (above the ankle) amputation of the index limb or death from any cause. The primary outcome for the economic analysis is cost per quality-adjusted life year. Secondary outcome measures include overall survival, major adverse limb events, major adverse cardiac events, relief of ischaemic pain, healing of tissue loss, and quality of life. The required sample size has been calculated at 861 participants (287 on each arm). These patients will be recruited over 3 years and followed-up for between 2 and 5 years. BASIL-3 is a pragmatic RCT designed to reflect current UK clinical practice. The results will inform decision-making regarding the appropriateness of funding the use of drug

  13. Bayesian network meta-analysis of nitinol stents, covered stents, drug-eluting stents, and drug-coated balloons in the femoropopliteal artery.

    Science.gov (United States)

    Katsanos, Konstantinos; Spiliopoulos, Stavros; Karunanithy, Narayan; Krokidis, Miltiadis; Sabharwal, Tarun; Taylor, Peter

    2014-04-01

    Several randomized controlled trials (RCTs) have shown the superiority of some of these technologies over balloon angioplasty, but direct comparisons between these treatment options are lacking. The authors conducted a network meta-analysis of RCTs comparing bare nitinol stents, covered nitinol stents, paclitaxel- or sirolimus-eluting stents (PES or SES), and paclitaxel-coated balloons (PCB) with plain balloon angioplasty or with each other in the femoropopliteal artery (PROSPERO registry: CRD42013004845). Sixteen RCTs comprising 2532 patients with 4227 person-years of follow-up were analyzed on an intention-to-treat basis. Bayesian random effects Poisson and binomial models were used for mixed treatment comparisons (WinBUGS). Clinical heterogeneity was accounted for by incorporating a meta-regression model on trial-specific baseline risk. End points included technical success, vascular restenosis, target lesion revascularization, and major amputations. Pairwise odds ratios and rate ratios (ORs and RRs) of absolute treatment effects were calculated, and the probabilities of each treatment being best are reported. Summary estimates are reported as the posterior median and associated credible intervals (CrIs) that serve the same purpose as confidence intervals in the context of the Bayesian framework. Extensive sensitivity, meta-regression, and network consistency analyses were performed to evaluate heterogeneity. Technical success was highest with covered stents (pooled OR, 13.6; 95% CrI, 3.3-31.1, probability best 82%) followed by uncovered stents (pooled OR, 7.0; 95% CrI, 2.6-129, probability best 18%) when compared with balloon angioplasty (reference treatment). Vascular restenosis was lowest with PES (RR, 0.43; 95% CrI, 0.16-1.18, probability best 45%) followed by PCB (RR, 0.43; 95% CrI, 0.26-0.67, probability best 42%). Target lesion revascularization was lowest with PCB (RR, 0.36; 95% CrI, 0.23-0.55, probability best 56%) followed by PES (RR, 0.42; 95% CrI, 0

  14. Emergency endovascular repair of iliac artery rupture caused by post-stenting angioplasty with an endograft

    Institute of Scientific and Technical Information of China (English)

    ZHOU Yu-bin; WU Dan-ming; XU Ke; WANG Cheng-gang; YI Wei; JIA Qi; SUN Yu-xin

    2007-01-01

    @@ Iliac artery rupture is a rare complication of poststenting angioplasty and can lead to massive lifethreatening haemorrhage. Conventional surgery can not repair the damaged vessel easily and may cause substantial blood loss and high operative morbidity and mortality. We report our experience with a selfexpanding covered endoprosthesis for endovascular repair of the rupture of an iliac artery caused by stenting angioplasty.

  15. Percutaneous transluminal angioplasty of the superficial femoral artery by retrograde catheterization via the popliteal artery

    DEFF Research Database (Denmark)

    Tønnesen, K H; Sager, P; Karle, A;

    1988-01-01

    We report the results of 50 angioplasty procedures via the popliteal artery. A 3-year follow-up including control of blood pressures at ankle and toe levels show results comparable to reports in the literature. This new approach for angioplasty of the superficial femoral artery and eventually...

  16. Impact of Diabetes on Long-Term Outcome After Primary Angioplasty

    DEFF Research Database (Denmark)

    De Luca, Giuseppe; Dirksen, Maurits T; Spaulding, Christian;

    2012-01-01

    Diabetes has been shown to be associated with worse survival and repeat target vessel revascularization (TVR) after primary angioplasty. The aim of the current study was to evaluate the impact of diabetes on long-term outcome in patients undergoing primary angioplasty treated with bare metal stents...

  17. The Dutch experience in percutaneous transluminal angioplasty of narrowed saphenous veins used for aortocoronary arterial bypass

    NARCIS (Netherlands)

    W.H.T. Plokker; H.J. Meester (Hannie); P.W.J.C. Serruys (Patrick)

    1991-01-01

    textabstractOf 19,994 percutaneous transluminal coronary angioplasty procedures performed in The Netherlands between April 1980 and January 1989, the long-term follow-up of 454 patients who underwent angioplasty of greater than or equal to 1 saphenous vein bypass graft was reviewed. In 46% of patien

  18. Emergency stenting for refractory acute coronary artery occlusion during coronary angioplasty

    NARCIS (Netherlands)

    P.J. de Feyter (Pim); I. DeScheerder (Ivan); M.J.B.M. van den Brand (Marcel); G-J. Laarman (GertJan); H. Suryapranata (Harry); P.W.J.C. Serruys (Patrick)

    1990-01-01

    markdownabstractAbstract Acute coronary artery occlusion occurs in 2 to 11% of the patients who undergo coronary angioplasty and is the major cause of in-hospital mortality and morbidity associated with coronary angioplasty. This procedural complication is usually caused by an occlusive

  19. Intragastric balloon and multidisciplinary team

    Directory of Open Access Journals (Sweden)

    R. A. Mazure

    Full Text Available Background: The intragastric balloon is widely used for weight reduction in obese patients, but results are variable. We describe our results enhancing the importance of a Multidisciplinary Team (MT taking part in the treatment. Methods: A retrospective review was done concerning a total of 119 balloons , placed in 116 patients, under endoscopic control and conscious sedation, from May 2001 until August 2006. 49 patients were prepared and recommended to be followed by a MT in a physical unit, at least every 15 days during 6 months. 67 were indicated and followed by other colleagues, without MT. Removal was performed 6 months later. Results: Concerning our 49 patients, mean age was 38, 1 years, 31 female and 18 males, with BMI ranged between 32 and 63, average of 42. The average decrease of weight excess was 31, 85% (-4, 45-80, 4%, and the BMI diminished 5,3 points (from 13,6 to gain of 0,9. The treatment failed in 34,6 % of our patients -including 4 patients lost of follow-up (8, 16%-, compared with 53, 8% of patients without structured MT for selection and follow-up. Physical exercise enhanced markedly the results with 45, 8% of excess of weight loss in women and 39, 7% in males, compared with 14, 6 and 15, 6% in patients who didn't follow the program. The weight loss was mostly fat mass, 89,9% in men and 75,6% in women.- The results maintenance was obtained in 40% of patients one year later. There were no major complications; one balloon had to be removed at 3 weeks because of intolerance, another at 5 months because of gastroesophageal reflux. Conclusions: BIB is an effective help to achieve a short term weight loss in obese patients; nevertheless, good and long lasting results will depend on the modification of life style obtained by a multidisciplinary approach.

  20. Vasoprotective effects of neurocompensatory response to balloon injury during diabetes involve the improvement of Mas signaling by TGFβ1 activation.

    Science.gov (United States)

    Pernomian, Larissa; Gomes, Mayara S; Pernomian, Laena; Moreira, Rafael P; Corrêa, Fernando M A; de Oliveira, Ana M

    2015-01-01

    Balloon injury in diabetic rats triggers a sensory neurocompensatory response that restores the blood flow in contralateral carotid. These vasoprotective effects result from H2O2-mediated relaxation that counteracts AT1-dependent contractile hyperreactivity. The most important mechanism from the renin-angiotensin-system in counteracting AT1-mediated effects is that one is mediated by Mas receptors. Thus, we hypothesized that the vasoprotective effects of balloon neurocompensation in diabetic rats could result from the improvement of Mas signaling by H2O2-mediated sensory mechanisms. NK1 receptors are sensory components whose activation could lead to H2O2 generation upon TGFβ1 release and ALK5-mediated Nox4 upregulation. Based on this, we aimed to investigate: (1) the role of the TGFβ1/ALK5-Nox4-H2O2 pathway on modulating Mas signaling in diabetic rat contralateral carotid; and (2) the contribution of Mas signaling in the control of local blood flow. Our results showed that balloon neurocompensation restored diabetic rat contralateral carotid flow by improving Mas signaling through NK1-mediated TGFβ1 release. TGFβ1/ALK5 activation enhanced Nox4 expression and Nox4-driven generation of H2O2. In turn, H2O2 enhanced the local Mas-mediated relaxation. Since restenosis impairs diabetic rat ipsilateral carotid flow, the restoration of diabetic rat contralateral carotid flow may prevent further damages in cerebral irrigation by carotid pathways after angioplasty during diabetes. Copyright © 2015 Elsevier Inc. All rights reserved.

  1. [Percutaneous angioplasty (PTA) in the treatment of non-penetrating injuries to the subclavian artery. A clinical case].

    Science.gov (United States)

    Giordanengo, F; Boneschi, M; Giorgetti, P L; Lovaria, A

    1996-05-01

    Non penetrating injuries to the subclavian vessels are uncommon. We present a case of a young patient with an isolated blunt trauma of the right subclavian artery. The patient, a 25 year-old woman, was admitted to our Institute after a motor-vehicle accident, with a physical findings of absent peripheral pulses and right clavicular fracture, confirmed by non-invasive vascular evaluation and X-ray of the chest. Diagnosis was established by an urgent selective angiography that showed a subintimal hematoma with occlusion of the vessel and peripheral ischemia of the arm. The patient clinical status (hemodynamically stable) permitted a conservative management and a transluminal percutaneous angioplasty (PTA) with a trans-femoral catheter balloon. After radiologic treatment, the patient showed good palpable peripheral pulses. Clavicular fracture was treated by esternal stabilization. We believe that in selected patients, without other serious life-threatening injures, the intimal artery injury can be treated by a conservative and now also radiologic Therapy; PTA treatment avoids morbidity and mortality associated with surgical intervention.

  2. Paraplegia following intraaortic balloon circulatory assistance

    Directory of Open Access Journals (Sweden)

    Benício Anderson

    1999-01-01

    Full Text Available Intraaortic balloon counterpulsation is frequently used in patients experiencing severe ventricular dysfunction following maximal drug therapy. However, even with the improvement of percutaneous insertion techniques, the procedure has always been followed by vascular, infectious, and neurological complications. This article describes a case of paraplegia due to intraaortic balloon counterpulsation in the postoperative period of cardiac surgery.

  3. Transradial approach for coronary angioplasty in Chinese elderly patients

    Institute of Scientific and Technical Information of China (English)

    CAO Zheng; ZHOU Yu-jie; ZHAO Ying-xin; LIU Yu-yang; SHI Dong-mei; GUO Yong-he; CHENG Wan-jun; NIE Bin; WANG Jian-long

    2008-01-01

    Background The radiaI artery is currently regarded as a useful vascular access site for coronary procedures.This study was conducted to investigate the feasibility and safety of the percutaneous radial artery approach for angioplasty in the elderly.Methods Two thousand and fifty-eight consecutive patients (762 elderly,age≥65 years;and 1296 non-elderly,age <65 years,respectively) who underwent transradial coronary angioplasty were recruited in this study.Study endpoints included procedure success rate,procedure time,vascular complications at access site,and major adverse cardiac and cerebrovascular events during hospitalization.Results Elderly patients were more likely to present with unstable angina and renal dysfunction.The incidence of radial and brachiocephalic trunk anatomical tortuosity was higher in elderly patients than that in non-elderly patients (11.5% vs 3.7%;8.9% vs 2.6%,P<0.01,respectively).However,procedural success rate(94.7% vs 95.6%)and total mean procedure time ((67.9±27.3)minutes vs (58.6±38.5) minutes) for transradial coronary angioplasty were not significantly different between the two groups.Clinical course during the hospitalization was slightly worse in the elderly patients because of more adverse cardiac and cerebrovascular events after the procedure.However,the incidence of vascular complications was not significantly different between the elderly and non-elderly patients.Conclusion Although the incidence of radial and brachiocephalic trunk anatomical tortuosity is higher in elderly patients,transradial coronary intervention can be performed with similar safety and procedural success in these patients as compared with non-elderly patients.

  4. The patients' perception of recovery after coronary angioplasty.

    Science.gov (United States)

    Higgins, M; Dunn, S; Theobald, K

    2000-08-01

    Coronary angioplasty and stent placement is associated with short hospital stays. Patients are expected to recover at home, alone, following limited care time with nurses. The purpose of the study was to describe participants' perceptions of recovery after angioplasty. Eight men and three women were interviewed 1 month after discharge from hospital. Verbatim transcripts were analysed for major themes using the qualitative techniques of grounded theory. Data analysis revealed three major categories: awareness of the problem, coping response and appraisal of the situation. These were linked via a problem solving process. In step one, the problem was identified. In step two, coping responses were taken to try and solve the problem. In step three, the results of the coping responses were appraised or evaluated. These categories were further defined by four phases identified as: pre-admission, admission, during the angioplasty and recovery. This paper describes the recovery phase. Awareness of the problem in the recovery phase was associated with 'relief from chest pain' for most participants. In contrast, anxiety continued and was associated with 'uncertainty over future health'. Participants described coping responses of "taking control of their life again" by undertaking both physical and psychological strategies. Finally, the situation was appraised to be either a 'good' or a 'bad' recovery. This appraisal was based on such considerations as the absence of chest pain, improvement in well-being and energy levels. The results of this study highlight patients' concerns and support the need for greater emphasis on their psychosocial needs. This care must be provided within the time constraints of short hospital stays. Nurses must also consider providing support to patients in the pre-admission and recovery phases.

  5. Carotid angioplasty and stent placement for restenosis after endarterectomy

    Energy Technology Data Exchange (ETDEWEB)

    Kadkhodayan, Yasha [Washington University School of Medicine, Interventional Neuroradiology, Mallinckrodt Institute of Radiology, St. Louis, MO (United States); Moran, Christopher J.; Cross, DeWitte T. [Washington University School of Medicine, Interventional Neuroradiology, Mallinckrodt Institute of Radiology, St. Louis, MO (United States); Washington University School of Medicine, Department of Neurological Surgery, St. Louis, MO (United States); Derdeyn, Colin P. [Washington University School of Medicine, Interventional Neuroradiology, Mallinckrodt Institute of Radiology, St. Louis, MO (United States); Washington University School of Medicine, Department of Neurological Surgery, St. Louis, MO (United States); Washington University School of Medicine, Department of Neurology, St. Louis, MO (United States)

    2007-04-15

    Recurrent carotid stenosis following endarterectomy is a common complication, and reoperation may be associated with increased morbidity. The goal of this study was to determine the procedural safety and long-term complication rates of carotid angioplasty and stenting for recurrent stenosis. Of 248 consecutive carotid angioplasty and/or stenting procedures performed at our institution between March 1996 and November 2005, 83 procedures for recurrent stenosis following endarterectomy were performed in 75 patients (mean age 68 years; 43 men, 32 women) without cerebral protection devices. The patients' medical records were retrospectively reviewed for vascular imaging reports and available clinical follow-up. Procedural and long-term complication rates were calculated. Recurrent stenosis was reduced from a mean of 80.6% to no significant stenosis in 82 of 83 procedures. The procedural stroke rate was 3 out of 83 procedures (3.6%). The procedural transient ischemic attack (TIA) rate was 2 out of 83 procedures (2.4%). Mean follow-up was 22.4 months (range 0.1 to 86.7 months) with at least 6 months follow-up for 54 of 83 procedures (65%). There were five TIAs and no strokes on follow-up (new TIAs at 25.5 and 43.4 months; recurrent TIAs at 1, 11.1, and 12 months, all with normal angiograms). The composite 30-day stroke, myocardial infarction, or death rate was 5 of 83 procedures (6.0%). In this series, angioplasty and stenting were effective in relieving stenosis secondary to recurrent carotid disease after endarterectomy, and have low rates of ischemic complications. (orig.)

  6. [Angioscopy and angioplasty of the iliac and femoral arteries].

    Science.gov (United States)

    Baudrillard, J C; Cécile, J P; Foucart, H; Carlier, C; Baidj, Z

    1990-01-01

    Angioscopy is a technique of endoscopic investigation of the vascular lumen and its contents, which we have coupled with iliac and femoral angioplasty. The material comprises 3 main elements: the angioscope, the TV-monitoring assembly and the infusion system. No complication was recorded in a series of 94 angioscopies (47 iliac, 44 distal femoral and 3 grafts) performed over a period of 18 months. The technical quality of the images obtained was good in 90% of cases (85/94). Angioscopy revealed lesions that had either been nonvisualized or underrated by angiography, and played a determinant role in 16% of cases (15/94), whereby the therapeutical procedure could be modified accordingly.

  7. Successful angioplasty during pregnancy for renal artery stenosis.

    Science.gov (United States)

    Margueritte, François; Velasco, Stephane; Pourrat, Olivier; Pierre, Fabrice

    2016-03-01

    Renal artery stenosis can be diagnosed during pregnancy and treated at the same time. A 30-year-old woman had a sudden, severe but asymptomatic hypertensive crisis at 21 weeks of gestation. The diagnosis of renal artery stenosis suspected on Doppler ultrasonography was confirmed and treated by renal angioplasty, which reduced her blood pressure. At 27 weeks of gestation, her blood pressure increased again, associated with significant proteinuria, suggesting pre-eclampsia. A cesarean section was performed giving birth to a healthy 940-g child. Renal artery stenosis should be considered when sudden and early-onset hypertension appears during pregnancy.

  8. Study of low-pressure premixed laminar n-heptane+ propane/oxygen/nitrogen flames

    Institute of Scientific and Technical Information of China (English)

    YU Wu; WEI LiXia; MA ZhiHao; HUANG ZuoHua; YUAN Tao; TIAN ZhenYu; LI YuYang

    2009-01-01

    Low-pressure premixed laminar n-heptane+propane/oxygen/nitrogen flames were investigated with tunable synchrotron vacuum ultraviolet (VUV) photoionization and molecular-beam sampling mass spectrometry. Three flames with different mass percentage of propane in the fuel blends of 0%, 10%, and 20% were studied. The combustion intermediates were identified by comparing the measured IEs with those values in literatures. Mole fraction profiles of the main species were compared among the three flames. The experimental results provide detailed data in understanding the combustion of n-heptane and n-heptane/propane blends in engine. They are also helpful in establishing and verifying the kinetic models.

  9. An experimental and kinetic modeling study of premixed nitromethane flames at low pressure

    DEFF Research Database (Denmark)

    Zhang, Kuiwen; Li, Yuyang; Yuan, Tao

    2011-01-01

    An experimental and modeling study is reported on three premixed nitromethane/oxygen/argon flames at low pressure (4.655kPa) with equivalence ratios (ϕ) of 1.0, 1.5 and 2.0. Flame species were identified with tunable synchrotron vacuum ultraviolet photoionization. The mole fraction profiles of more...... against experimental results of all three flames. The computed predictions showed satisfactory agreement with the experimental results. Based on a rate-of-production analysis, reaction pathway diagrams were obtained to describe the hydrocarbon oxidation process and nitrogenous species chemistry...

  10. Unsteady effects at the interface between impeller-vaned diffuser in a low pressure centrifugal compressor

    Directory of Open Access Journals (Sweden)

    Mihai Leonida NICULESCU

    2013-03-01

    Full Text Available In this paper, Proper Orthogonal Decomposition (POD is applied to the analysis of the unsteady rotor-stator interaction in a low-pressure centrifugal compressor. Numerical simulations are carried out through finite volumes method using the Unsteady Reynolds-Averaged Navier-Stokes Equations (URANS model. Proper Orthogonal Decomposition allows an accurate reconstruction of flow field using only a small number of modes; therefore, this method is one of the best tools for data storage. The POD results and the data obtained by the Adamczyk decomposition are compared. Both decompositions show the behavior of unsteady rotor-stator interaction, but the POD modes allow quantifying better the numerical errors.

  11. Investigation of Low-Pressure Turbine Endwall Flows: Simulations and Experiments (Postprint)

    Science.gov (United States)

    2015-01-01

    Endwall Losses of High Lift Low Pressure Turbine Vanes ,” Ph.D. Dissertation, Air Force Institute of Technology, 2012 13Sauer, H., Muller, R., and...2001, pp. 207-213 14Zess, G., and Thole, K., “Computational Design and Experimental Evaluation of Using a Leading Edge Fillet on a Gas Turbine Vane ,” J...Turbine,” ASME Paper 94-GT-249, 1994 19Harvey, N., Rose, M., Taylor, M., Shahpar, S., Hartland, J., and Gregory- Smith , D., “Nonaxisymmetric turbine

  12. Low pressure water vapour plasma treatment of surfaces for biomolecules decontamination.

    OpenAIRE

    Fumagalli, F; Kylian, O; Amato, Letizia; Hanus, J; Rossi, F.

    2012-01-01

    Decontamination treatments of surfaces are performed on bacterial spores, albumin and brain homogenate used as models of biological contaminations in a low-pressure, inductively coupled plasma reactor operated with water-vapour-based gas mixtures. It is shown that removal of contamination can be achieved using pure H2O or Ar/H2O mixtures at low temperatures with removal rates comparable to oxygen-based mixtures. Particle fluxes (Ar+ ions, O and H atomic radicals and OH molecular radicals) fro...

  13. Cure Reaction Kinetics of Low Pressure Sheet Molding Compound System Thickened by Crystalline Polymer

    Institute of Scientific and Technical Information of China (English)

    QIN Yan; LIU Haihua; HUANG Zhixiong; MEI Qilin

    2007-01-01

    Several kinetic models for unsaturated polyester cure reaction and some existing parameter estimation techniques of these models were introduced. Correlated kinetic parameters and kinetic equations of the autocatalytic empirical kinetic model of LPSMC system were determined by using isothermal DSC to scan the system which was thickened by crystalline polymer (PEG-MAH). Through using a serial curing degree of the system to validate the model, the experimental results were basically identical with the predictions of the autocatalytic empirical kinetic model. This model could provide a theoretical reference to the determination of molding techniques of low pressure SMC.

  14. Cavity ringdown laser absorption spectroscopy detection of formyl (HCO) radical in a low pressure flame

    Science.gov (United States)

    Scherer, J. J.; Rakestraw, D. J.

    1997-01-01

    The formyl radical has been detected via the ÖX˜ system in a low pressure CH 4/N 2/O 2 flame using cavity ringdown laser absorption spectroscopy. The direct absorption data obtained in these initial studies allows determination of the absolute HCO concentration in the flame of ca. 2.1(±0.9) × 10 13 mol cm -3, which is in excellent agreement with flame chemistry simulations. The extrapolated detection limit at 300 K of ≈ 1.4(±0.6) × 10 11 mol cm -3 is comparable to that of other methods, including intracavity laser absorption spectroscopy.

  15. Remote sensing of a low pressure plasma in the radio near field

    Science.gov (United States)

    Kelly, Seán; McNally, Patrick J.

    2017-09-01

    A novel approach to remotely monitor low pressure non-equilibrium plasmas is reported. A magnetic field antenna is positioned in the near field of a capacitively coupled plasma. Magnetic flux from plasma currents, present near the viewport, is intercepted by a calibrated loop antenna placed outside the chamber. The induced signal current is correlated to bulk plasma currents. The comparison of relative harmonic amplitudes shows resonance features for lower operating pressures. The geometric resonance and electron-neutral collision frequencies are evaluated from resonant harmonic features. This approach advances remote, noninvasive, and installation-free plasma monitoring, which is of particular interest to industrial scenarios.

  16. Ion time-of-flight study of laser ablation of silver in low pressure gases

    DEFF Research Database (Denmark)

    Hansen, T.N.; Schou, Jørgen; Lunney, J.G.

    1999-01-01

    The dynamics of ions from a laser-ablated silver target in low pressure background atmospheres have been investigated in a simple geometry using an electrical probe. A simple scattering picture for the first transmitted peak of the observed plume splitting has been used to calculate cross section...... of the ablated silver ions in oxygen (sigma{O(2)} = 4.8 x 10(-16) cm(2)) and in argon (sigma{Ar} = 6.7 x 10(-16) cm(2)). The dynamics of the blast wave is well described by blast wave theory. (C) 1999 Elsevier Science B.V. All rights reserved....

  17. Low pressure water vapour discharge as a light source: I. Spectroscopic characteristics and efficiency

    Energy Technology Data Exchange (ETDEWEB)

    Artamonova, E; Artamonova, T; Beliaeva, A; Gorbov, D; Khodorkovskii, M; Melnikov, A; Milenin, V; Murashov, S; Rakcheeva, L; Timofeev, N [Saint-Petersburg State University, Ulyanovskaya 3, 198504 (Russian Federation); Michael, D [General Electric Global Research Center, One Research Circle (Bldg K1 Rm 4B31), Niskayuna, NY, 12309 (United States)], E-mail: timofeev@pobox.spbu.ru, E-mail: michael@crd.ge.com

    2008-08-07

    Spectral and electrical characteristics of a low pressure dc discharge formed from a mixture of one of the rare gases Ne, Ar or Kr plus water vapour are studied. Water vapour is only a minor additive to the rare gas. It has been shown that enhanced emission of the OH 306.4 nm band is registered from the discharge of Ar mixed with water vapour. Plasmas from the other investigated rare gases yielded considerably less OH 306.4 nm emission. Data about consumed electric power, spectra and relative efficiencies are presente000.

  18. Electron energy probability function and L-p similarity in low pressure inductively coupled bounded plasma

    OpenAIRE

    Chatterjee, Sanghamitro; Bhattacharjee, Sudeep; Charles, Christine; Boswell, Rod

    2015-01-01

    Particle-In-Cell (PIC) simulations are carried out to investigate the effect of discharge length (L) and pressure (p) on Electron Energy Probability Function (EEPF) in a low pressure radio frequency (rf) inductively coupled plasma (ICP) at 13.56 MHz. It is found that for both cases of varying L (0.1–0.5 m) and p (1–10 mTorr), the EEPF is a bi-Maxwellian with a step in the bounded direction (x) and non-Maxwellian with a hot tail in the symmetric unbounded directions (y, z). The plasma space po...

  19. Low pressure water vapour plasma treatment of surfaces for biomolecules decontamination

    DEFF Research Database (Denmark)

    Fumagalli, F; Kylian, O; Amato, Letizia

    2012-01-01

    be achieved using pure H2O or Ar/H2O mixtures at low temperatures with removal rates comparable to oxygen-based mixtures. Particle fluxes (Ar+ ions, O and H atomic radicals and OH molecular radicals) from water vapour discharge are measured by optical emission spectroscopy and Langmuir probe under several......Decontamination treatments of surfaces are performed on bacterial spores, albumin and brain homogenate used as models of biological contaminations in a low-pressure, inductively coupled plasma reactor operated with water-vapour-based gas mixtures. It is shown that removal of contamination can...

  20. Experimental measurement of the thermal stability criteria for low pressure methanol synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Berty, J.M.; Lenczyk, J.P.; Shah, S.M.

    1982-11-01

    The mathematical basis was derived for the experimental measurement of the ''Slope Condition'' and of the ''Dynamic Condition'' of the thermal stability criteria in a laboratory-scale internal recycle reactor. This work also resulted in clearer interpretations and simpler expressions for the two stability criteria. The method was experimentally demonstrated on the example of the low pressure methanol synthesis. Only seven experiments were needed to evaluate the stability criteria of this reaction for which the kinetics is unknown.

  1. Is the use of low-pressure pulsatile lavage for pressure ulcer management associated with environmental contamination with Acinetobacter baumannii?

    Science.gov (United States)

    Ho, Chester H; Johnson, Tova; Miklacic, Joan; Donskey, Curtis J

    2009-10-01

    Ho CH, Johnson T, Miklacic J, Donskey CJ. Is the use of low-pressure pulsatile lavage for pressure ulcer management associated with environmental contamination with Acinetobacter baumannii? To determine the extent of environmental contamination associated with low-pressure pulsatile lavage of stage III or IV pressure ulcers in patients with spinal cord injury (SCI) when routine infection control precautions are used for wounds colonized or infected with Acinetobacter baumannii. Prospective investigation in which pressure ulcer cultures and environmental cultures were obtained before and after low-pressure pulsatile lavage treatment, and before and after regular dressing changes. Environmental cultures included the patient's bedrail and settle plates placed 0.6, 1.5, and 2.4m from the wound to assess airborne spread of A. baumannii. SCI inpatient unit in a Department of Veterans Affairs Medical Center. Inpatients (N=15) with SCI receiving daily low-pressure pulsatile lavage treatment for stage III or IV pressure ulcers with standard dressing change, as well as regular dressing changes without low-pressure pulsatile lavage at other times of the day. Standard, regular dressing changes and dressing changes with low-pressure pulsatile lavage. Comparison of frequency of environmental contamination with A. baumannii associated with low-pressure pulsatile lavage versus regular dressing changes. Of the 15 SCI inpatients meeting inclusion criteria, 9 (60%) grew A. baumannii from their wounds. Of the 9 patients with wound cultures positive for A. baumannii, only 1 (11%) had environmental contamination with this organism after performance of low-pressure pulsatile lavage, and the same patient had environmental contamination after a standard dressing change. The antibiotic susceptibility patterns of the wound and environmental A. baumannii isolates were identical. Low-pressure pulsatile lavage using the infection control methods described is not associated with an increased

  2. Who is responsible for the consequences? A case of stent thrombosis subsequent to noncompliance with post angioplasty treatment regimen.

    Science.gov (United States)

    Sajwani, Salma Abdul Aziz; Allana, Saleema

    2014-01-01

    Coronary artery disease (CAD) is a major cause of mortality internationally and in Pakistan. Angioplasty has been proven to be an effective treatment for CAD. Stent thrombosis is a known but preventable complication of angioplasty. Several factors may lead to stent thrombosis with non-compliance with the prescribed drug regimen, being one of the most important factors. We report a case of stent thrombosis after four months of angioplasty. After exploring of patient's post angioplasty routines, it was found that the patient was non-compliant with the prescribed anti- platelets and other prescribed drugs. This time the patient presented with another acute myocardial infarction, and he went through angioplasty again.

  3. The protective effect of bergamot oil extract on lecitine-like oxyLDL receptor-1 expression in balloon injury-related neointima formation.

    Science.gov (United States)

    Mollace, Vincenzo; Ragusa, Salvatore; Sacco, Iolanda; Muscoli, Carolina; Sculco, Francesca; Visalli, Valeria; Palma, Ernesto; Muscoli, Saverio; Mondello, Luigi; Dugo, Paola; Rotiroti, Domenicantonio; Romeo, Francesco

    2008-06-01

    Lectin-like oxyLDL receptor-1 (LOX-1) has recently been suggested to be involved in smooth muscle cell (SMC) proliferation and neointima formation in injured blood vessels. This study evaluates the effect of the nonvolatile fraction (NVF), the antioxidant component of bergamot essential oil (BEO), on LOX-1 expression and free radical generation in a model of rat angioplasty. Common carotid arteries injured by balloon angioplasty were removed after 14 days for histopathological, biochemical, and immunohistochemical studies. Balloon injury led to a significant restenosis with SMC proliferation and neointima formation, accompanied by increased expression of LOX-1 receptor, malondialdehyde and superoxide formation, and nitrotyrosine staining. Pretreatment of rats with BEO-NVF reduced the neointima proliferation together with free radical formation and LOX-1 expression in a dose-dependent manner. These results suggest that natural antioxidants may be relevant in the treatment of vascular disorders in which proliferation of SMCs and oxyLDL-related endothelial cell dysfunction are involved.

  4. Effect of Low Pressure End Conditions on Steam Power Plant Performance

    Directory of Open Access Journals (Sweden)

    Ali Syed Haider

    2014-07-01

    Full Text Available Most of the electricity produced throughout the world today is from steam power plants and improving the performance of power plants is crucial to minimize the greenhouse gas emissions and fuel consumption. Energy efficiency of a thermal power plant strongly depends on its boiler-condenser operating conditions. The low pressure end conditions of a condenser have influence on the power output, steam consumption and efficiency of a plant. Hence, the objective this paper is to study the effect of the low pressure end conditions on a steam power plant performance. For the study each component was modelled thermodynamically. Simulation was done and the results showed that performance of the condenser is highly a function of its pressure which in turn depends on the flow rate and temperature of the cooling water. Furthermore, when the condenser pressure increases both net power output and plant efficiency decrease whereas the steam consumption increases. The results can be used to run a steam power cycle at optimum conditions.

  5. Laparoscopic Cholecystectomy Under Spinal Anesthesia with Low-Pressure Pneumoperitoneum - Prospective Study of 150 Cases

    Directory of Open Access Journals (Sweden)

    Sunder Goyal

    2012-08-01

    Materials and Methods: In a private rural medical college, 150 patients were selected prospectively for laparoscopic cholecystectomy, under low-pressure (8mmHg pneumoperitoneum and under spinal anesthesia over a span of one and a half years. Injection bupivacaine (0.5% was used for spinal anesthesia. All ports were made in a head-down position to avoid hypotension. Shoulder pain was managed by reassurance as well as by diverting the attention and sedation in a few cases. Results: We successfully performed the operations in 145 patients without major complications. Spinal anesthesia was converted to general anesthesia in five patients due to severe shoulder pain. Age varied between 21 and 75 years. Duration of operation time (skin to skin was between 40 and 80 minutes. Twenty-nine patients complained of right shoulder pain. Most of them were managed by reassurance from the anesthetist and a few needed an injection of fentanyl along with midazolam. Conclusion: Laparoscopic cholecystectomy with low-pressure CO2 pneumoperitoneum is feasible and safe under spinal anesthesia. Incidence of postoperative shoulder pain and complications are comparable with laparoscopic cholecystectomy under general anesthesia. [Arch Clin Exp Surg 2012; 1(4.000: 224-228

  6. Kinetic mechanism for low-pressure oxygen/methane ignition and combustion

    Science.gov (United States)

    Slavinskaya, N. A.; Wiegand, M.; Starcke, J. H.; Riedel, U.; Haidn, O. J.; Suslov, D.

    2013-03-01

    It is known that during a launch of a rocket, the interaction of the exhaust gases of rocket engines with the atmosphere causes a local depletion of the ozone layer. In order to study these chemical processes in detail, a chemical reaction mechanism of the methane oxidation appropriate for high- and low-pressure conditions and a chemical reactor network to reproduce operating conditions in rocket engines and in the environment have been developed. An earlier developed detailed chemical kinetic model for the high-pressure CH4/O2 combustion has been improved for the low pressure and low temperature methane combustion and augmented with a submodel for NOx formation. The main model improvements are related to the pressure depending reactions. The model has been validated for operating conditions of 0.02 jet. Simulations performed have shown that the exhaust gases of a methane/oxygen propelled liquid rocket engine contain high amounts of active radicals, which can influence the formation of nitrogen compounds and consume ozone in the atmosphere.

  7. An expression for the h l factor in low-pressure electronegative plasma discharges

    Science.gov (United States)

    Chabert, P.

    2016-04-01

    The positive ion flux exiting a low-pressure plasma discharge is a crucial quantity in global (volume-averaged) models. In discharges containing only electrons and positive ions (electropositive discharges), it is common to write this flux {Γ\\text{wall}}={{h}\\text{l}}{{n}\\text{i0}}{{u}\\text{B}} , where {{n}\\text{i0}} is the central positive ion density, {{u}\\text{B}} is the positive ion fluid speed at the sheath edge (the Bohm speed), and {{h}\\text{l}} is the positive ion edge-to-centre density ratio. There are well established formulae for {{h}\\text{l}} in electropositive discharges, but for discharges containing negative ions (electronegative discharges), the analysis is more complicated. The purpose of this paper is to propose a formula for the {{h}\\text{l}} factor in low-pressure electronegative discharges. We use the numerical solution of fluid equations with Boltzmann negative ions, including Poisson’s equation, as a guide to derive an analytical expression that can easily be incorporated in global models. The parameter space in which the derived expression is valid is discussed at the end of the paper.

  8. Evacuation of coal from hoppers/silos with low pressure pneumatic blasting systems

    Science.gov (United States)

    Fischer, J. S.

    1977-01-01

    The need for an efficient, economical, effective and quiet device for moving coal and other difficult bulk solids was recognized. Thus came the advent of the low pressure pneumatic blasting system - a very efficient means of using a small amount of plant air (up to 125 PSI) to eliminate the most troublesome material hang-ups in storage containers. This simple device has one moving part and uses approximately 3% of the air consumed by a pneumatic vibrator on the same job. The principle of operation is very simple: air stored in the unit's reservoir is expelled directly into the material via a patented quick release valve. The number, size, and placement of the blaster units on the storage vessel is determined by a series of tests to ascertain flowability of the problem material. These tests in conjunction with the hopper or silo configuration determine specification of a low pressure pneumatic blasting system. This concept has often proven effective in solving flow problems when all other means have failed.

  9. Weak interactions between water and clathrate-forming gases at low pressures

    Energy Technology Data Exchange (ETDEWEB)

    Thurmer, Konrad; Yuan, Chunqing; Kimmel, Gregory A.; Kay, Bruce D.; Smith, R. Scott

    2015-11-01

    Using scanning probe microscopy and temperature programed desorption we examined the interaction between water and two common clathrate-forming gases, methane and isobutane, at low temperature and low pressure. Water co-deposited with up to 10-1 mbar methane or 10-5 mbar isobutane at 140 K onto a Pt(111) substrate yielded pure crystalline ice, i.e., the exposure to up to ~107 gas molecules for each deposited water molecule did not have any detectable effect on the growing films. Exposing metastable, less than 2 molecular layers thick, water films to 10-5 mbar methane does not alter their morphology, suggesting that the presence of the Pt(111) surface is not a strong driver for hydrate formation. This weak water-gas interaction at low pressures is supported by our thermal desorption measurements from amorphous solid water and crystalline ice where 1 ML of methane desorbs near ~43 K and isobutane desorbs near ~100 K. Similar desorption temperatures were observed for desorption from amorphous solid water.

  10. Phosphorus recovery from sewage sludge with a hybrid process of low pressure wet oxidation and nanofiltration.

    Science.gov (United States)

    Blöcher, Christoph; Niewersch, Claudia; Melin, Thomas

    2012-04-15

    Phosphorus recovery from sewage sludge will become increasingly important within the next decades due to depletion of mineral phosphorus resources. In this work a new process concept was investigated, which aims at realising phosphorus recovery in a synergistic way with the overall sewage sludge treatment scheme. This process combines a low pressure wet oxidation for sewage sludge decomposition as well as phosphorus dissolution and a nanofiltration process to separate phosphorus from heavy metals and obtain a clean diluted phosphoric acid, from which phosphorus can be recovered as clean fertiliser. It was shown that this process concept is feasible for sewage sludge for wastewater treatment plants that apply enhanced biological removal or precipitation with alumina salts for phosphorus removal. The critical parameter for phosphorus dissolution in the low pressure wet oxidation process is the iron concentration, while in the nanofiltration multi-valent cations play a predominant role. In total, a phosphorus recovery of 54% was obtained for an exemplary wastewater treatment plant. Costs of the entire process are in the same range as conventional sewage sludge disposal, with the benefit being phosphorus recovery and reduced emission of greenhouse gases due to avoidance of sludge incineration.

  11. Annularly grooved membrane combined with rood beam piezoresistive pressure sensor for low pressure applications.

    Science.gov (United States)

    Li, Chuang; Cordovilla, Francisco; Ocaña, José L

    2017-03-01

    A novel structural piezoresistive pressure sensor with annularly grooved membrane combined with rood beam has been proposed for low pressure measurements based on silicon substrate. In this study, a design method, including the model design, dimensions optimization, and performance prediction of the novel structure sensor, is presented. The finite element method has been used to analyze the stress distribution of sensitive elements and the deflection of membrane. On the basis of simulation results, the relationships between structural dimension variables and mechanical performance are deduced, which make the fabrication processes more efficient. According to statistics theory, the coefficient of determination R(2) and residual sum of squares are introduced to indicate whether the fitting equations and curves match well with the simulation results. After that, a series of the optimal membrane dimensions are determined. Compared with other structural sensors, the optimized sensor achieves the best overall properties as it mitigates the contradiction between sensitivity and linearity. The reasons why the proposed sensor can maximize sensitivity and minimize nonlinearity are also discussed. By localizing more strain energy in the high concentrated stress profile and creating partially stiffened membrane, the proposed sensor has achieved a high sensitivity of 34.5 (mV/V)/psi and a low nonlinearity of 0.25% FSS. Thus, the proposed structure sensor will be a proper choice for low pressure applications less than 1 psi.

  12. Annularly grooved membrane combined with rood beam piezoresistive pressure sensor for low pressure applications

    Science.gov (United States)

    Li, Chuang; Cordovilla, Francisco; Ocaña, José L.

    2017-03-01

    A novel structural piezoresistive pressure sensor with annularly grooved membrane combined with rood beam has been proposed for low pressure measurements based on silicon substrate. In this study, a design method, including the model design, dimensions optimization, and performance prediction of the novel structure sensor, is presented. The finite element method has been used to analyze the stress distribution of sensitive elements and the deflection of membrane. On the basis of simulation results, the relationships between structural dimension variables and mechanical performance are deduced, which make the fabrication processes more efficient. According to statistics theory, the coefficient of determination R2 and residual sum of squares are introduced to indicate whether the fitting equations and curves match well with the simulation results. After that, a series of the optimal membrane dimensions are determined. Compared with other structural sensors, the optimized sensor achieves the best overall properties as it mitigates the contradiction between sensitivity and linearity. The reasons why the proposed sensor can maximize sensitivity and minimize nonlinearity are also discussed. By localizing more strain energy in the high concentrated stress profile and creating partially stiffened membrane, the proposed sensor has achieved a high sensitivity of 34.5 (mV/V)/psi and a low nonlinearity of 0.25% FSS. Thus, the proposed structure sensor will be a proper choice for low pressure applications less than 1 psi.

  13. Quantitative and sensitive analysis of CN molecules using laser induced low pressure He plasma

    Energy Technology Data Exchange (ETDEWEB)

    Pardede, Marincan [Department of Electrical Engineering, University of Pelita Harapan, 1100 M.H. Thamrin Boulevard, Lippo Village, Tangerang 15811 (Indonesia); Hedwig, Rinda [Department of Computer Engineering, Bina Nusantara University, 9 K.H. Syahdan, Jakarta 14810 (Indonesia); Abdulmadjid, Syahrun Nur; Lahna, Kurnia; Idris, Nasrullah; Ramli, Muliadi [Department of Physics, Faculty of Mathematics and Natural Sciences, Syiah Kuala University, Darussalam, Banda Aceh 23111, NAD (Indonesia); Jobiliong, Eric [Department of Industrial Engineering, University of Pelita Harapan, 1100 M.H. Thamrin Boulevard, Lippo Village, Tangerang 15811 (Indonesia); Suyanto, Hery [Department of Physics, Faculty of Mathematics and Natural Sciences, Udayana University, Kampus Bukit Jimbaran, Denpasar 80361, Bali (Indonesia); Marpaung, Alion Mangasi [Department of Physics, Faculty of Mathematics and Natural Sciences, Jakarta State University, 10 Rawamangun, Jakarta 13220 (Indonesia); Suliyanti, Maria Margaretha [Research Center for Physics, Indonesia Institute of Sciences, Kawasan Puspiptek, Serpong, Tangerang Selatan, 15314 Banten (Indonesia); Tjia, May On [Physics of Magnetism and Photonics Group, Faculty of Mathematics and Natural Sciences, Bandung Institute of Technology, 10 Ganesha, Bandung 40132 (Indonesia); Research Center of Maju Makmur Mandiri Foundation, 40/80 Srengseng Raya, Jakarta 11630 (Indonesia); Lie, Tjung Jie; Lie, Zener Sukra; Kurniawan, Davy Putra; Kurniawan, Koo Hendrik, E-mail: kurnia18@cbn.net.id [Research Center of Maju Makmur Mandiri Foundation, 40/80 Srengseng Raya, Jakarta 11630 (Indonesia); Kagawa, Kiichiro [Research Center of Maju Makmur Mandiri Foundation, 40/80 Srengseng Raya, Jakarta 11630 (Indonesia); Fukui Science Education Academy, Takagi Chuou 2 choume, Fukui 910-0804 (Japan)

    2015-03-21

    We report the results of experimental study on CN 388.3 nm and C I 247.8 nm emission characteristics using 40 mJ laser irradiation with He and N{sub 2} ambient gases. The results obtained with N{sub 2} ambient gas show undesirable interference effect between the native CN emission and the emission of CN molecules arising from the recombination of native C ablated from the sample with the N dissociated from the ambient gas. This problem is overcome by the use of He ambient gas at low pressure of 2 kPa, which also offers the additional advantages of cleaner and stronger emission lines. The result of applying this favorable experimental condition to emission spectrochemical measurement of milk sample having various protein concentrations is shown to yield a close to linear calibration curve with near zero extrapolated intercept. Additionally, a low detection limit of 5 μg/g is found in this experiment, making it potentially applicable for quantitative and sensitive CN analysis. The visibility of laser induced breakdown spectroscopy with low pressure He gas is also demonstrated by the result of its application to spectrochemical analysis of fossil samples. Furthermore, with the use of CO{sub 2} ambient gas at 600 Pa mimicking the Mars atmosphere, this technique also shows promising applications to exploration in Mars.

  14. A 10-GHz Bandwidth Electroabsorption Modulated Laser by Ultra-Low-Pressure Selective Area Growth

    Institute of Scientific and Technical Information of China (English)

    ZHAO Qian; PAN Jiao-Qing; ZHOU Fan; WANG Bao-Jun; WANG Lu-Feng; WANG Wei

    2005-01-01

    @@ A novel integration technique has been developed using band-gap energy control of InGaAsP/InGaAsP multi quantum-well (MQW) structures during simultaneous ultra-low-pressure (22 mbar) selective-area-growth (SAG)process in metal-organic chemical vapour deposition. A fundamental study of the controllability of band gap energy by the SAG method is performed. A large band-gap photoluminescence wavelength shift of 83nm is obtained with a small mask width variation (0-30μm). The method is then applied to fabricate an MQW distributed-feedback laser monolithically integrated with an electroabsorption modulator. The experimental results exhibit superior device characteristics with low threshold of 19 mA, over 24 dB extinction ratio when coupled into a single mode fibre. More than 10 GHz modulation bandwidth is also achieved, which demonstrates that the ultra-low-pressure SAG technique is a promising approach for high-speed transmission photonic integrated circuits.

  15. The role of thermal energy accommodation and atomic recombination probabilities in low pressure oxygen plasmas

    Science.gov (United States)

    Gibson, Andrew Robert; Foucher, Mickaël; Marinov, Daniil; Chabert, Pascal; Gans, Timo; Kushner, Mark J.; Booth, Jean-Paul

    2017-02-01

    Surface interaction probabilities are critical parameters that determine the behaviour of low pressure plasmas and so are crucial input parameters for plasma simulations that play a key role in determining their accuracy. However, these parameters are difficult to estimate without in situ measurements. In this work, the role of two prominent surface interaction probabilities, the atomic oxygen recombination coefficient γ O and the thermal energy accommodation coefficient α E in determining the plasma properties of low pressure inductively coupled oxygen plasmas are investigated using two-dimensional fluid-kinetic simulations. These plasmas are the type used for semiconductor processing. It was found that α E plays a crucial role in determining the neutral gas temperature and neutral gas density. Through this dependency, the value of α E also determines a range of other plasma properties such as the atomic oxygen density, the plasma potential, the electron temperature, and ion bombardment energy and neutral-to-ion flux ratio at the wafer holder. The main role of γ O is in determining the atomic oxygen density and flux to the wafer holder along with the neutral-to-ion flux ratio. It was found that the plasma properties are most sensitive to each coefficient when the value of the coefficient is small causing the losses of atomic oxygen and thermal energy to be surface interaction limited rather than transport limited.

  16. Combination of Low-pressure Steam Explosion and Alkaline Peroxide Pretreatment for Separation of Hemicellulose

    Directory of Open Access Journals (Sweden)

    Yang Xing

    2014-04-01

    Full Text Available Low-pressure steam explosion (LPSE combined with alkaline peroxide (AP pretreatment was first employed to separate hemicellulose from Lespedeza stalks. The monosaccharide composition and molecular weight distribution of the obtained hemicellulose fractions were characterized in this study. The results show that the hemicellulose extracted from Lespedeza stalks consisted of xylose, glucose, galactose, and mannose, which was a mixture of arabinoxylans and xyloglucans or β-glucans. The yield of hemicellulose fractions after AP pretreatment ranged from 11.2% (2.5% hydrogen peroxide (H2O2, w/v for 12 h to 12.2% (3.3% H2O2, w/v for 72 h. The molecular weight of hemicellulose decreased from 2,458 g/mol to 1,984 g/mol after AP pretreatment, indicating its degradation reaction. The structure of hemicellulose was analyzed by Fourier transform infrared spectroscopy, proton nuclear magnetic resonance, and heteronuclear single quantum coherence. The AP pretreatment partially cleaved the backbone and the ether linkage between lignin and hemicelluloses. Also, branched-chain α-D-arabinofuranosyl in which β-D-xylose substituted at the C-3 position (monosubstituted was removed, illustrating a partial debranching reaction. Therefore, the combination of low-pressure steam explosion and alkaline peroxide pretreatment (LPSE-AP is an effective pretreatment method to separate hemicellulose from Lespedeza stalk.

  17. Electrical Properties for Capacitively Coupled Radio Frequency Discharges of Helium and Neon at Low Pressure

    Science.gov (United States)

    Tanisli, Murat; Sahin, Neslihan; Demir, Suleyman

    2016-10-01

    In this study, the symmetric radio frequency (RF) electrode discharge is formed between the two electrodes placing symmetric parallel. The electrical properties of symmetric capacitive RF discharge of pure neon and pure helium have been obtained from current and voltage waveforms. Calculations are done according to the homogeneous discharge model of capacitively coupled radio frequency (CCRF) using with the data in detail. Electrical properties of bulk plasma and sheath capacitance are also investigated at low pressure with this model. This study compares the electrical characteristics and sheath capacitance changes with RF power and pressure for helium and neon discharges. Also, the aim of the study is to see the differences between helium and neon discharges' current and voltage values. Their root-mean-square voltages and currents are obtained from Tektronix 3052C oscilloscope. Modified homogeneous discharge model of CCRF is used for low pressure discharges and the calculations are done using experimental results. It is seen that homogeneous discharge model of CCRF is usable with modification and then helium and neon discharge's electrical properties are investigated and presented with a comparison. Helium discharge's voltage and current characteristic have smaller values than neon's. It may be said that neon discharge is a better conductor than helium discharge. It is seen that the sheath capacitance is inversely correlation with sheath resistance.

  18. Determination of the cathode and anode voltage drops in high power low-pressure amalgam lamps

    Energy Technology Data Exchange (ETDEWEB)

    Vasilyak, L. M., E-mail: vasilyak@ihed.ras.ru [Russian Academy of Sciences, Joint Institute for High Temperatures (Russian Federation); Vasiliev, A. I., E-mail: vasiliev@npo.lit.ru; Kostyuchenko, S. V.; Sokolov, D. V.; Startsev, A. Yu. [Joint Stock Company NPO LIT (Russian Federation); Kudryavtsev, N. N. [Moscow Institute of Physics and Technology (State University) (Russian Federation)

    2011-12-15

    For the first time, cathode and anode drops of powerful low-pressure amalgam lamps were measured. The lamp discharge current is 3.2 A, discharge current frequency is 43 kHz, linear electric power is 2.4 W/cm. The method of determination of a cathode drop is based on the change of a lamp operating voltage at variation of the electrode filament current at constant discharge current. The total (cathode plus anode) drop of voltage was measured by other, independent ways. The maximum cathode fall is 10.8 V; the anode fall corresponding to the maximal cathode fall is 2.4 V. It is shown that in powerful low pressure amalgam lamps the anode fall makes a considerable contribution (in certain cases, the basic one) to heating of electrodes. Therefore, the anode fall cannot be neglected, at design an electrode and ballast of amalgam lamps with operating discharge current frequency of tens of kHz.

  19. A 10-GHz Bandwidth Electroabsorption Modulated Laser by Ultra-Low-Pressure Selective Area Growth

    Science.gov (United States)

    Zhao, Qian; Pan, Jiao-Qing; Zhou, Fan; Wang, Bao-Jun; Wang, Lu-Feng; Wang, Wei

    2005-08-01

    A novel integration technique has been developed using band-gap energy control of InGaAsP/InGaAsP multi-quantum-well (MQW) structures during simultaneous ultra-low-pressure (22 mbar) selective-area-growth (SAG) process in metal-organic chemical vapour deposition. A fundamental study of the controllability of band gap energy by the SAG method is performed. A large band-gap photoluminescence wavelength shift of 83 nm is obtained with a small mask width variation (0-30 μm). The method is then applied to fabricate an MQW distributed-feedback laser monolithically integrated with an electroabsorption modulator. The experimental results exhibit superior device characteristics with low threshold of 19 mA, over 24 dB extinction ratio when coupled into a single mode fibre. More than 10 GHz modulation bandwidth is also achieved, which demonstrates that the ultra-low-pressure SAG technique is a promising approach for high-speed transmission photonic integrated circuits.

  20. Analisis Numerikal Frekuensi Natural Pada Poros Low Pressure Boiler Feed Pump PT.PJB UP Gresik

    Directory of Open Access Journals (Sweden)

    Muhammad Taufik Akbar Ofrial

    2017-03-01

    Full Text Available Low pressure boiler feed pump (LPBFP merupakan salah satu komponen penting dalam sistem Heat Recovery Steam Generator (HRSG, pada pengoperasiannya sering terjadi permasalahan yaitu patahnya poros yang dapat terjadi 8-10 kali dalam setahun yang mungkin disebabkan oleh faktor getaran. Untuk itu pada penelitian ini dilakukan perhitungan dengan pemodelan metode elemen hingga menggunakan software ANSYS untuk menghitung frekuensi natural dan modus getaran untuk 10 frekuensi natural pertama pada komponen LPBFP. Dari hasil simulasi didapatkan nilai yaitu untuk orde pertama sebesar 583,03 Hz, orde kedua sebesar 583,39 Hz, orde ketiga sebesar 2820,8 Hz, orde keempat sebesar 2849 Hz, orde kelima sebesar 3943,9 Hz, orde keenam sebesar 4079,6 Hz, orde ketujuh sebesar 5428,3 Hz, orde kedelapan sebesar 6111 Hz, orde kesembilan sebesar 6594 Hz, orde kesepuluh sebesar 6715 Hz. Sepuluh frekuensi natural menghasilkan lima jenis modus getaran yaitu lateral bending vibration, shear bending vibration, torsional bending vibration, axial bending vibration, torsional shear bending vibration. Dari kesepuluh frekuensi natural yang diperoleh semuanya menyebabkan kegagalan poros low pressure boiler feed pump.

  1. Development of a low-pressure materials pre-treatment process for improved energy efficiency

    Science.gov (United States)

    Lee, Kwanghee; You, Byung Don

    2017-09-01

    Low pressure materials pre-treatment process has been developed as an alternative to the existing high-temperature sludge drying, limestone calcination, and limonite dehydroxylation. Using the thermodynamic equilibrium relationship between temperature and pressure represented by the Clausius-Clapeyron equation, the operational temperature of these reactions could be lowered at reduced pressure for increased energy efficiency. For industrial sludge drying, the evaporation rate was controlled by interfacial kinetics showing a constant rate with time and significant acceleration in the reaction could be observed with reduced pressure. At this modified reaction rate under low pressure, the rate was also partially controlled by mass transfer. Temperature of limestone calcination was lowered, but the reaction was limited at the calculated equilibrium temperature of the Clausius-Clapeyron equation and slightly higher temperatures were required. The energy consumption during limestone calcination and limonite dehydroxylation were evaluated, where lower processing pressures could enhance the energy efficiency for limestone calcination, but limonite dehydroxylation could not achieve energy-savings due to the greater power consumption of the vacuum pump under lower pressure and reduced temperatures.

  2. Low-Pressure Pericardial Tamponade: Case Report and Review of the Literature.

    Science.gov (United States)

    Walsh, Brooks M; Tobias, Lauren A

    2017-04-01

    Focused cardiac ultrasound (FoCUS) is accurate for determining the presence of a pericardial effusion. Using FoCUS to evaluate for pericardial tamponade, however, is more involved. Many experts teach that tamponade is unlikely if the inferior vena cava (IVC) shows respiratory variation and is not distended. A 53-year-old woman presented to the emergency department (ED) with severe orthostatic hypotension, exertional dyspnea, and hypoxia. The evaluation did not reveal an acute cardiopulmonary etiology, but FoCUS demonstrated a pericardial effusion, with several signs consistent with tamponade. The IVC, however, was not distended. She was believed to be hypovolemic, but fluid therapy provided minimal benefit. The patient's condition improved only after aspiration of the effusion. The patient's presentation was likely a "low-pressure" pericardial tamponade. Patients with this subset of tamponade often do not have significant venous congestion, but urgent pericardial aspiration is still indicated. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: Pericardial tamponade may not manifest with IVC plethora on ultrasound. Patients with low-pressure tamponade do not present with the most florid signs of tamponade, but they nonetheless fulfill diagnostic criteria for tamponade. If a non-plethoric IVC is used to rule out tamponade, the clinician risks delaying comprehensive echocardiography or other tests. Furthermore, the potential for deterioration to frank shock could be discounted, with inappropriate disposition and monitoring. Copyright © 2016 Elsevier Inc. All rights reserved.

  3. Inactivation differences of microorganisms by low pressure UV and pulsed xenon lamps.

    Science.gov (United States)

    Otaki, M; Okuda, A; Tajima, K; Iwasaki, T; Kinoshita, S; Ohgaki, S

    2003-01-01

    UV disinfection has been applied to water treatment in recent years with low-pressure and medium-pressure UV lamps mainly used as the light source. In general, UV disinfection is considered to be inefficient with water of high turbidity because of inhibition of light penetration. Additionally, photoreactivation may be a problem that should be considered in case a disinfected water is discharged to the environment where sunlight causes reactivation. Recently, other types of lamps have been proposed including a flush-type lamp (such as a pulsed-xenon lamp) that emits high energy and wide wavelength intermittently. In this study, the difference between inactivation efficiencies by low-pressure UV (LPUV) and pulsed-xenon (PXe) lamps was investigated using two coliphage types and three strains of Escherichia coli. PXe had a suppressive effect on photoreactivation rate of the E. coli strains even though there was no significant effect on inactivation rate and maximum survival ratio after photoreactivation. PXe also had a benefit when applied to high turbidity waters as no tailing phenomena were observed in the low survival ratio area although it was observed in LPUV inactivation. This efficiency difference was considered to be due to the difference in irradiated wavelength of both lamps.

  4. Heat Transfer Model for Hot Air Balloons

    Science.gov (United States)

    Llado-Gambin, Adriana

    A heat transfer model and analysis for hot air balloons is presented in this work, backed with a flow simulation using SolidWorks. The objective is to understand the major heat losses in the balloon and to identify the parameters that affect most its flight performance. Results show that more than 70% of the heat losses are due to the emitted radiation from the balloon envelope and that convection losses represent around 20% of the total. A simulated heating source is also included in the modeling based on typical thermal input from a balloon propane burner. The burner duty cycle to keep a constant altitude can vary from 10% to 28% depending on the atmospheric conditions, and the ambient temperature is the parameter that most affects the total thermal input needed. The simulation and analysis also predict that the gas temperature inside the balloon decreases at a rate of -0.25 K/s when there is no burner activity, and it increases at a rate of +1 K/s when the balloon pilot operates the burner. The results were compared to actual flight data and they show very good agreement indicating that the major physical processes responsible for balloon performance aloft are accurately captured in the simulation.

  5. Pressure estimation for diamond anvils cell under very-low pressures, hydrostatic conditions -evaluation for quartz Raman peak shifts-

    Science.gov (United States)

    Kubo, K.; Okamoto, K.

    2016-12-01

    Pressure shift of the ruby R1 luminescent shift has been used as primary pressure gauge in diamond-anvils experiments. However, the pressure calibration under low-pressure conditions (Ruby pressure gauge at 1 GPa.

  6. Gating system optimization of low pressure casting A356 aluminum alloy intake manifold based on numerical simulation

    National Research Council Canada - National Science Library

    Jiang Wenming Fan Zitian

    2014-01-01

    To eliminate the shrinkage porosity in low pressure casting of an A356 aluminum alloy intake manifold casting, numerical simulation on filling and solidification processes of the casting was carried...

  7. Knockdown of connexin 43 attenuates balloon injury-induced vascular restenosis through the inhibition of the proliferation and migration of vascular smooth muscle cells.

    Science.gov (United States)

    Han, Xiao-Jian; He, Dan; Xu, Liang-Jing; Chen, Min; Wang, Yi-Qi; Feng, Jiu-Geng; Wei, Min-Jun; Hong, Tao; Jiang, Li-Ping

    2015-11-01

    Coronary artery disease (CAD) or atherosclerotic heart disease is one of the most common types of cardiovascular disease. Although percutaneous coronary intervention [PCI or percutaneous transluminal coronary angioplasty (PTCA)] is a mature, well-established technique used to treat atherosclerotic heart disease, its long‑term therapeutic effects are compromised by a high incidence of vascular restenosis (RS) following angioplasty. In our previous study, we found that the principal gap junction protein, connexin 43 (Cx43), in vascular smooth muscle cells (VSMCs) was involved in the development of vascular RS following angioplasty-induced balloon injury. However, the exact role action of Cx43 in vascular RS remains unclear. In the present study, we aimed to further examine whether the knockdown of Cx43 attenuates the development of vascular RS through the inhibition of the proliferation and migration of VSMCs. We found that the use of a lentiviral vector expressing shRNA targeting Cx43 (Cx43‑RNAi-LV) efficiently silenced the mRNA and protein expression of Cx43 in cultured VSMCs. In addition, MTT and Transwell assays were used to examined the proliferation and migration of the VSMCs, respectively. The results revealed that the knockdown of Cx43 by Cx43-RNAi-LV at a multiplicity of infection (MOI) of 100 significantly inhibited the proliferation and migration of the VSMCs in vitro. Notably, the knockdown of Cx43 also effectively attenuated the development of vascular RS and intimal hyperplasia following balloon injury in vivo. Taken together, our data suggest that Cx43 is involved in the development of vascular RS and intimal hyperplasia through the regulation of the proliferation and migration of VSMCs. Thus, the present study provides new insight into the pathogenesis of vascular RS, and suggests that further comfirms that Cx43 may well be a novel potential pharmacological target for preventing vascular RS following PCI.

  8. Percutaneous transluminal angioplasty (PTA) of supra-aortic arteries especially the internal carotid artery

    Energy Technology Data Exchange (ETDEWEB)

    Kachel, R.; Basche, S. (Medizinische Akademie, Erfurt (Germany, F.R.). Radiologische Klinik); Heerklotz, I.; Grossmann, K. (Medizinische Akademie, Erfurt (Germany, F.R.). Klinik fuer Innere Medizin); Endler, S. (Medizinische Akademie, Erfurt (Germany, F.R.). Klinik fuer Neurologie und Psychiatrie)

    1991-06-01

    We present our experience with 105 patients in whom percutaneous transluminal angioplasty was performed in 112 stenosed or occluded supra-aortic arteries. Symtoms of cerebrovascular and/or vertebrobasilar insufficiency were present in 104 of the 105 patients. The angioplasty was successful in 35 stenoses of the internal carotid artery, 2 stenoses of the common carotid artery, 1 stenosis of the external carotid artery, 15 stenoses of the vertebral artery, 3 stenoses of the innominate artery and 44 stenoses of the subclavian artery. There were only 4 minor-complications (2 haematomas, 1 transient ischemic attack, 1 small thrombus of the internal carotid artery which was detected by 111-indium platelet scintigraphy and treated by thrombendarterectomy before the appearance of neurological symptoms). All patients were symptom free after angioplasty. During the observations period of 3 to 109 months (average 58 months) there were only two cases with re-stenosis after subclavian angioplasty. The results of more than 700 personal and international published percutaneous transluminal angioplasties of supra-aortic arteries are presented. The results suggest that angioplasty of supra-aortic arteries is an effective method. On strict definition of the indications, the complication rate for angioplasty of the supra-aortic arteries is not likely to be higher than that for operative treatment. (orig.).

  9. Airborne Internet Providing Tethered Balloon System

    Directory of Open Access Journals (Sweden)

    Suvriti Dhawan1

    2015-12-01

    Full Text Available In this paper we shall introduce a new system for providing wireless network communication over a specified area using ’lighter than air’ balloons. This technology will replace the existing fiber optic network system. This will be done by using a tethered balloon along with the payload (containing a receiver, a transmitter and a radio communication device.This payload will be suspended from the ground at an altitude (depending on the area of coverage required. Users under this area will be able to access this system directly for internet connectivity. This system can be used over large areas like universities, companies and societies to provide internet facility to their users through Wi-Fi or over an area where the user is specified (commercial purposes. Currently Google is working on similar idea called the ’Google Loon’ in which they use high altitude balloons which float at an altitude twice as high as air planes and the weather. They recently tested this system over New-Zealand by providing internet to their pilot testers on ground. Their balloons not being stationary, move with directional winds and have to be replaced one after the other to maintain consistency. This can be a huge problem over the areas where upper atmospheric winds are not in favorable direction. We can resolve this problem by using our stationary tethered balloon system which can communicate with the loon balloons to provide internet facility over a desired area. Moreover when our balloon will communicate with the loon balloon it will increase the coverage area as the loon balloon has to communicate to a point which is above the ground. Our system will not only replace the existing fiber optic system but it will also be selfsustaining i.e. It will generate its own power using solar panels.

  10. Stratospheric electric field measurements with transmediterranean balloons

    Science.gov (United States)

    de La Morena, B. A.; Alberca, L. F.; Curto, J. J.; Holzworth, R. H.

    1993-01-01

    The horizontal component of the stratospheric electric field was measured using a balloon in the ODISEA Campaign of Transmediterranean Balloon Program. The balloon flew between Trapani (Sicily) and El Arenosillo (Huelva, Spain) along the 39 deg N parallel at a height between 34 and 24 km. The high values found for the field on fair-weather and its quasi-turbulent variation, both in amplitude and direction, are difficult to explain with the classical electric field source. A new source, first described by Holzworth (1989), is considered as possibly causing them.

  11. The balloon and the airship technological heritage

    Science.gov (United States)

    Mayer, N. J.

    1981-01-01

    The balloon and the airship are discussed with emphasis on the identification of commonalities and distinctions. The aerostat technology behind the shape and structure of the vehicles is reviewed, including a discussion of structural weight, internal pressure, buckling, and the development of a stable tethered balloon system. Proper materials for the envelope are considered, taking elongation and stress into account, and flight operation and future developments are reviewed. Airships and tethered balloons which are designed to carry high operating pressure with low gas loss characteristics are found to share similar problems in low speed flight operations, while possessing interchangeable technologies.

  12. Looners: Inside the world of balloon fetishism

    OpenAIRE

    McIntyre, Karen E

    2011-01-01

    In the spring of 1997, Shaun had just broken up with a boyfriend, and his roommate had moved out. Living alone for the first time and relieved of the fear that someone might walk in the door, he was finally able to indulge his fantasy. The young man sat on his couch and started blowing up balloons. Shaun had loved playing with balloons since he was a child. When he hit puberty, he felt his first orgasm rubbing against a balloon. It was then that his relationship with the object took ...

  13. A balloon-borne integrating nephelometer

    Energy Technology Data Exchange (ETDEWEB)

    Brown, G.S.; Apple, M.L. (Sandia National Labs., Albuquerque, NM (USA)); Weiss, R.E. (Radiance Research, Seattle, WA (USA))

    1990-09-01

    A balloon-borne integrating nephelometer has been successfully developed and flown by Sandia National Laboratories and Radiance Research. This report details instrument design, calibration and data conversion procedure. Free and tethered balloon transport and telemetry systems are described. Data taken during March 1989 South-Central New Mexico free flight ascents are presented as vertical profiles of atmospheric particle scattering coefficient, temperature and balloon heading. Data taken during December 1989 Albuquerque, New Mexico tethered flights are also presented as vertical profiles. Data analysis shows superior instrument performance. 5 refs., 22 figs.

  14. Looners: Inside the world of balloon fetishism

    OpenAIRE

    McIntyre, Karen E

    2011-01-01

    In the spring of 1997, Shaun had just broken up with a boyfriend, and his roommate had moved out. Living alone for the first time and relieved of the fear that someone might walk in the door, he was finally able to indulge his fantasy. The young man sat on his couch and started blowing up balloons. Shaun had loved playing with balloons since he was a child. When he hit puberty, he felt his first orgasm rubbing against a balloon. It was then that his relationship with the object took ...

  15. Trajectories of Rubber Balloons used in Balloon Releases: Theory and Application

    CERN Document Server

    Glaschke, Patrick

    2011-01-01

    Balloon releases are one of the main attractions of many fairs. Helium filled rubber balloons are released to carry postcards over preferably long distances. Although such balloons have been considered in atmospheric sciences and air safety analysis, there is only scarce literature available on the subject. This work intends to close this gap by providing a comprehensive theoretical overview and a thorough analysis of real-life data. All relevant physical properties of a rubber balloon are carefully modelled and supplemented by weather observations to form a self-contained trajectory simulation tool. The analysis of diverse balloon releases provided detailed insight into the flight dynamics and potential optimisations. Helium balloons are found to reach routinely altitudes above 10 km. Under optimal conditions, they could stay more than 24 hours airborne while reaching flight distances close to 3000 km. However, external weather effects reduce the typical lifetime to 2-5 hours.

  16. Balloon-expandable covered stent therapy of complex endovascular pathology.

    Science.gov (United States)

    Giles, Heath; Lesar, Christopher; Erdoes, Luke; Sprouse, Richard; Myers, Stuart

    2008-11-01

    restenosis rate included two renal artery occlusions in patients noncompliant with clopidogrel use and resulted in ipsilateral kidney loss in both patients. In-stent peak systolic velocities decreased significantly (p<0.05) from preoperation to 12 months in iliac stents and to 18 months in renal stents. Ankle-brachial index increased significantly in iliac stents from preoperation (0.62+/-0.18) to 18 months (0.86+/-0.16). Successful exclusion of atheromatous lesions and aneurysm/dissection/endoleak was 100%. Access-site complications occurred in 6%: pseudoaneurysm (n=2), dissection (n=1), and bleeding (n=1). Balloon-expandable covered stents have an acceptable primary patency with an excellent assisted patency after salvage angioplasty. The clinical utility of this technology is broad for the treatment of aneurysms, extravasation, unstable atheromatous lesions, and recurrent in-stent restenosis.

  17. Development and Commercial Application of Ultra-Low Pressure Naphtha Reforming Technology with Continuous Catalyst Regeneration

    Institute of Scientific and Technical Information of China (English)

    Ma Aizeng; Xu Youchun; Yang Dong; Zhang Xinkuan; Wang Jieguang

    2013-01-01

    The development history and major technological innovations of the ultra-low pressure naphtha reforming tech-nology with continuous catalyst regeneration in China were introduced. This technology had been adopted by the 1.0 Mt/a CCR unit at the Guangzhou Company. The appropriate catalyst was selected to meet the demand of the unit capacity, the feedstock, and the product slate. The design parameters, including the reaction pressure, the octane number of C5+ liquid product, the reaction temperature, the space velocity, the hydrogen/oil molar ratio, and the catalyst circulating rate, were chosen based on the study of process conditions and parameters. The commercial test results showed that the research oc-tane number of C5+ product reached 104 when the capacity of the CCR unit was 100% and 115% of the design value. The other technical targets attained or exceeded the expected value.

  18. Calibration of Relative Humidity Devices in Low-pressure, Low-temperature CO2 Environment

    Science.gov (United States)

    Genzer, Maria; Polkko, Jouni; Nikkanen, Timo; Hieta, Maria; Harri, Ari-Matti

    2017-04-01

    Calibration of relative humidity devices requires in minimum two humidity points - dry (0%RH) and (near)saturation (95-100%RH) - over the expected operational temperature and pressure range of the device. In terrestrial applications these are relatively easy to achieve using for example N2 gas as dry medium, and water vapor saturation chambers for producing saturation and intermediate humidity points. But for example in applications intended for meteorological measurements on Mars there is a need to achieve at least dry and saturation points in low-temperature, low-pressure CO2 environment. We have developed a custom-made, small, relatively low-cost calibration chamber able to produce both dry points and saturation points in Martian range pressure CO2, in temperatures down to -70°C. The system utilizes a commercially available temperature chamber for temperature control, vacuum vessels and pumps. The main pressure vessel with the devices under test inside is placed inside the temperature chamber, and the pressure inside is controlled by pumps and manual valves and monitored with a commercial pressure reference with calibration traceable to national standards. Air, CO2, or if needed another gas like N2, is used for filling the vessel until the desired pressure is achieved. Another pressure vessel with a dedicated pressure pump is used as the saturation chamber. This vessel is placed in the room outside the temperature chamber, partly filled with water and used for achieving saturated water vapor in room-temperature low-pressure environment. The saturation chamber is connected to the main pressure vessel via valves. In this system dry point, low-pressure CO2 environment is achieved by filling the main pressure vessel with dry CO2 gas until the desired pressure is achieved. A constant flow of gas is maintained with the pump and valves and monitored with the pressure reference. The saturation point is then achieved by adding some water vapor from the saturation

  19. Discrete element simulation of powder compaction in cold uniaxial pressing with low pressure

    Science.gov (United States)

    Rojek, Jerzy; Nosewicz, Szymon; Jurczak, Kamila; Chmielewski, Marcin; Bochenek, Kamil; Pietrzak, Katarzyna

    2016-11-01

    This paper presents numerical studies of powder compaction in cold uniaxial pressing. The powder compaction in this work is considered as an initial stage of a hot pressing process so it is realized with relatively low pressure (up to 50 MPa). Hence the attention has been focused on the densification mechanisms at this range of pressure and models suitable for these conditions. The discrete element method employing spherical particles has been used in the numerical studies. Numerical simulations have been performed for two different contact models—the elastic Hertz-Mindlin-Deresiewicz model and the plastic Storåkers model. Numerical results have been compared with the results of laboratory tests of the die compaction of the NiAl powder. Comparisons have shown that the discrete element method is capable to represent properly the densification mechanisms by the particle rearrangement and particle deformation.

  20. Transient evolution of solitary electron holes in low pressure laboratory plasma

    CERN Document Server

    Choudhary, Mangilal; Mukherjee, Subroto

    2015-01-01

    Solitary electrons holes (SEHs) are localized electrostatic positive potential structures in collisionless plasmas. These are vortex-like structures in the electron phase space. Its existence is cause of distortion of the electron distribution in the resonant region. These are explained theoretically first time by Schamel et.al [Phys. Scr. 20, 336 (1979) and Phys. Plasmas 19, 020501 (2012)]. Propagating solitary electron holes can also be formed in a laboratory plasma when a fast rising high positive voltage pulse is applied to a metallic electrode [Kar et. al., Phys. Plasmas 17, 102113 (2010)] immersed in a low pressure plasma. The temporal evolution of these structures can be studied by measuring the transient electron distribution function (EDF). In the present work, transient EDF is measured after formation of a solitary electron hole in nearly uniform, unmagnetized, and collisionless plasma for applied pulse width and, where and are applied pulse width and inverse of ion plasma frequency respectively. Fo...

  1. Fabrication of Planar Heterojunction Perovskite Solar Cells by Controlled Low-Pressure Vapor Annealing.

    Science.gov (United States)

    Li, Yanbo; Cooper, Jason K; Buonsanti, Raffaella; Giannini, Cinzia; Liu, Yi; Toma, Francesca M; Sharp, Ian D

    2015-02-05

    A new method for achieving high efficiency planar CH3NH3I3-xClx perovskite photovoltaics, based on a low pressure, reduced temperature vapor annealing is demonstrated. Heterojunction devices based on this hybrid halide perovskite exhibit a top PCE of 16.8%, reduced J-V hysteresis, and highly repeatable performance without need for a mesoporous or nanocrystalline metal oxide layer. Our findings demonstrate that large hysteresis is not an inherent feature of planar heterojunctions, and that efficient charge extraction can be achieved with uniform halide perovskite materials with desired composition. X-ray diffraction, valence band spectroscopy, and transient absorption measurements of these thin films reveal that structural modifications induced by chlorine clearly dominate over chemical and electronic doping effects, without affecting the Fermi level or photocarrier lifetime in the material.

  2. Natural Circulation Characteristics at Low-Pressure Conditions through PANDA Experiments and ATHLET Simulations

    Directory of Open Access Journals (Sweden)

    Domenico Paladino

    2008-01-01

    Full Text Available Natural circulation characteristics at low pressure/low power have been studied by performing experimental investigations and numerical simulations. The PANDA large-scale facility was used to provide valuable, high quality data on natural circulation characteristics as a function of several parameters and for a wide range of operating conditions. The new experimental data allow for testing and improving the capabilities of the thermal-hydraulic computer codes to be used for treating natural circulation loops in a range with increased attention. This paper presents a synthesis of a part of the results obtained within the EU-Project NACUSP “natural circulation and stability performance of boiling water reactors.” It does so by using the experimental results produced in PANDA and by showing some examples of numerical simulations performed with the thermal-hydraulic code ATHLET.

  3. Experimental testing of cooling by low pressure adsorption in a zeolite

    Energy Technology Data Exchange (ETDEWEB)

    Redman, C.M.

    1985-01-01

    A small scale facility was designed, constructed, and utilized to test the use of zeolite adsorption of water vapor to augment chill storage in ice for conventional space cooling. The facility uses solar-derived energy, for the heat source and evaporatively chilled water for the heat sump. The product cooling uses sublimation of ice instead of melting. The ZCAT facility utilizes a heat pumping technique in which a water vapor adsorbent functions as the compressor and condenser. The design was based on use of 13X zeolite as the adsorber because of its high adsorbence at low pressures. However, it has been determined that other materials such as silica gel should give superior performance. While zeolite 13X holds more water in the pressure and temperature ranges of interest, silica gel cycles more water and has less residue water. Both points are very important in the design of an efficient and cost effective system.

  4. Numerical simulation and optimization of Al alloy cylinder body by low pressure die casting

    Directory of Open Access Journals (Sweden)

    Mi Guofa

    2008-05-01

    Full Text Available Shrinkage defects can be formed easily at Critical location during low pressure die casting (LPDC of aluminum alloy cylinder body. It has harmful effect on the products. Mold fi lling and solidifi cation process of a cylinder body was simulated by using of Z-CAST software. The casting method was improved based on the simulation results. In order to create effective feeding passage, the structure of casting was modifi ed by changing the location of strengthening ribs at the bottom, without causing any adverse effect on the part’s performance. Inserting copper billet at suitable location of the die is a valid way to create suitable solidifi cation sequence that is benefi cial to the feeding. Using these methods, the shrinkage defect was completely eliminated at the critical location.

  5. Low-pressure phase diagram of crystalline benzene from quantum Monte Carlo

    Science.gov (United States)

    Azadi, Sam; Cohen, R. E.

    2016-08-01

    We studied the low-pressure (0-10 GPa) phase diagram of crystalline benzene using quantum Monte Carlo and density functional theory (DFT) methods. We performed diffusion quantum Monte Carlo (DMC) calculations to obtain accurate static phase diagrams as benchmarks for modern van der Waals density functionals. Using density functional perturbation theory, we computed the phonon contributions to the free energies. Our DFT enthalpy-pressure phase diagrams indicate that the Pbca and P21/c structures are the most stable phases within the studied pressure range. The DMC Gibbs free-energy calculations predict that the room temperature Pbca to P21/c phase transition occurs at 2.1(1) GPa. This prediction is consistent with available experimental results at room temperature. Our DMC calculations give 50.6 ± 0.5 kJ/mol for crystalline benzene lattice energy.

  6. Low pressure mediated enhancement of nanoparticle and macromolecule loading into porous silicon structures.

    Science.gov (United States)

    Leonard, Fransisca; Margulis-Goshen, Katrin; Liu, Xuewu; Srinivasan, Srimeenakshi; Magdassi, Shlomo; Godin, Biana

    2014-01-01

    Ensuring drug loading efficiency and consistency is one of the most critical stages in engineering drug delivery vectors based on porous materials. Here we propose a technique to significantly enhance the efficiency of loading by employing simple and widely available methods: applying low pressure with and without centrifugation. Our results point toward the advantages the proposed method over the passive loading, especially where the size difference of loaded materials and the pore size of the porous silicon particles is smaller, an increase up to 20-fold can be observed. The technique described in the study can be used for efficient and reproducible loading of porous materials with therapeutic molecules, nanoparticles and contrast imaging agents for biomedical application.

  7. Qualitative model of the operating mechanism of the protective coating for low pressure Hg lamps

    Energy Technology Data Exchange (ETDEWEB)

    Krasnochub, A V [DECO Ltd, PO Box 40, 141701 Dolgoprudnyi (Russian Federation); Vasiliev, A I [LIT Technology Ltd, Krasnobogatyrskaya 44, 107076 Moscow (Russian Federation)

    2006-04-07

    Interaction between the plasma and protective coating on the inner side of low pressure mercury lamp bulbs is considered. Under the assumption that the main way of decreasing the transmission of the bulb wall is the implantation of Hg ions within the fused quartz and formation of complexes [HgO] therein, a qualitative model of the attenuation mechanism is offered. The influence of the characteristics of a coating (thickness, close-packed structures, the lattice parameter, mass of atoms) on the transmission of the bulb walls is analysed. On the basis of the suggested model, estimates of the change in minimum transmission of bulb walls were made for lamps with and without protective coating. It is shown that in spite of approximations, the proposed model is in good agreement with experimental data.

  8. CATS, a low pressure multiwire proportional chamber for secondary beam tracking at GANIL

    CERN Document Server

    Ottini-Hustache, S; Auger, F; Musumarra, A; Alamanos, N; Cahan, B; Gillibert, A; Lagoyannis, A; Maillard, O; Pollacco, E; Sida, J L; Riallot, M

    1999-01-01

    A beam detector system, CATS (Chambre A Trajectoires de Saclay), was designed to provide event-by-event particle tracking in experiments with radioactive beams at GANIL. It consists of two low pressure multiwire proportional chambers with one plane of anode wires placed between two cathode planes (active area: 70x70 mm sup 2), respectively segmented into 28 vertical or horizontal strips (2.54 mm wide). The anode wires deliver a time signal allowing a time of flight measurement with an accuracy between 440 ps and 1.2 ns, depending on the energy loss of incident particles in the detector. The cathode strips are individually read out and the position of incoming particles is reconstructed using a charge centroid finding algorithm. A spatial resolution of 400 mu m (700 mu m) was achieved during in beam experiment, with a counting rate of 1.5x10 sup 5 (10 sup 6) particles per second. (author)

  9. Wastewater disinfection by low-pressure UV and ozone: a design approach based on water quality.

    Science.gov (United States)

    Savoye, P; Janex, M L; Lazarova, V

    2001-01-01

    Disinfection processes are known to be very sensitive to wastewater quality. This paper discusses the parameters that impact the UV light (UV) and ozone disinfection processes and the related mechanisms based on literature review. Low-pressure UV and ozone technologies were investigated on effluents that covered a wide range of water quality. The results are given in terms of design doses required to meet three major disinfection standards. Both processes were found eligible for the majority of effluents tested. Although cost-effectiveness is usually considered more favourable to UV, the ozone alternative should be examined in cases such as the disinfection of low-quality effluents or large treatment plants. Ozonation was also found capable of meeting the stringent Title 22 standard with no coagulation at a dose of 10 mg/l.

  10. Optimization of process parameter for synthesis of silicon quantum dots using low pressure chemical vapour deposition

    Indian Academy of Sciences (India)

    Dipika Barbadikar; Rashmi Gautam; Sanjay Sahare; Rajendra Patrikar; Jatin Bhatt

    2013-06-01

    Si quantum dots-based structures are studied recently for performance enhancement in electronic devices. This paper presents an attempt to get high density quantum dots (QDs) by low pressure chemical vapour deposition (LPCVD) on SiO2 substrate. Surface treatment, annealing and rapid thermal processing (RTP) are performed to study their effect on size and density of QDs. The samples are also studied using Fourier transformation infrared spectroscopy (FTIR), atomic force microscopy (AFM), scanning electron microscopy (SEM) and photoluminescence study (PL). The influence of Si–OH bonds formed due to surface treatment on the density of QDs is discussed. Present study also discusses the influence of surface treatment and annealing on QD formation.

  11. Stress corrosion cracking in low-pressure turbine discs in an NaCl solution

    Energy Technology Data Exchange (ETDEWEB)

    Hitomi, Itoh [Mitsubishi Heavy Industries, Ltd., Takasago Research and Development Center (Japan); Takashi, Momoo [Mitsubishi Heavy Industries, Ltd., Takasago Machinery Works (Japan)

    2001-07-01

    From past research, it is known that stress corrosion cracking in low-pressure turbine discs occurs in an environment near that of deaerated pure water. Nevertheless, in units with molar ratio control, there is a possibility of NaCl concentrating as an impurity in the dry/wet boundary region. Long-term immersion tests were conducted at 373 K to 473 K with the NaCl concentration predicted to become 5%. It was found that, when FeCl{sub 3} or other oxidizer was added, corrosion increased remarkably and SCC was initiated. When cracks were initiated, they were primarily transgranular; as the test temperature was decreased, initiation was accelerated but conversely crack propagation was reduced. (author)

  12. On designing low pressure loss working spaces for a planar Stirling micromachine

    Science.gov (United States)

    Hachey, M.-A.; Léveillé, É.; Fréchette, L. G.; Formosa, F.

    2015-12-01

    In this paper, research was undertaken with the objective to design low pressure loss working spaces for a Stirling cycle micro heat engine operating from low temperature waste heat. This planar free-piston heat engine is anticipated to operate at the kHz level with mm3 displacement. Given the resonant nature of the free-piston configuration, the complexity of its working gas’ flow geometry and its projected high operating frequency, flow analysis is relatively complex. Design considerations were thus based on fast prototyping and experimentation. Results show that geometrical features, such as a sharp 90° corner between the regenerator and working spaces, are strong contributors to pressure losses. This research culminated into a promising revised working space configuration for engine start-up, as it considerably reduced total pressure losses, more than 80% at Re = 700, from the original design.

  13. Plasma-photocatalyst interaction: Production of oxygen atoms in a low pressure discharge

    Science.gov (United States)

    Guaitella, O.; Gatilova, L.; Rousseau, A.

    2005-04-01

    A pulsed dc low pressure discharge in air (210 Pa) is used to study the mechanisms of activation of a photocatalytic material (TiO2) under plasma exposure. It is first shown that the presence of TiO2 inside the plasma region leads to a strong increase of the reduced electric field. Time resolved measurement of the atomic oxygen density is performed by actinometry during a 10 ms pulse at a low repetition rate (1 Hz) with and without TiO2 pellets inside the plasma region. The presence of TiO2 pellets strongly increases the O atom density during the first millisecond, but this effect saturates for longer exposure times.

  14. Dynamics of cathode spots in low-pressure arc plasma removing oxide layer on steel surfaces

    Science.gov (United States)

    Tang, Z. L.; Yang, K.; Liu, H. X.; Zhang, Y. C.; Li, H.; Zhu, X. D.

    2016-03-01

    The dynamics of cathode spots has been investigated in low-pressure arc plasma for removing oxide layer on low carbon steel surfaces. The motion of cathode spots was observed with a high speed camera, and the arc voltage was analyzed by fast Fourier transform. The spots move on clean steel surface as a random walk, and the low-frequency components dominated the voltage waveform. However, the spots on steel surfaces with oxide layer tend to burn on the rim of the eroded area formed in the previous arcing, and the low-frequency components decrease correspondingly. The "color" of the colored random noise for arc voltage varies from the approximate brown noise for clean steel surface to pink noise for thick oxide layer, where the edge effect of boundary is considered to play a significant role.

  15. Comparison measurements of low-pressure between a laser refractometer and ultrasonic manometer

    Science.gov (United States)

    Egan, Patrick F.; Stone, Jack A.; Ricker, Jacob E.; Hendricks, Jay H.

    2016-05-01

    We have developed a new low-pressure sensor which is based on the measurement of (nitrogen) gas refractivity inside a Fabry-Perot cavity. We compare pressure determinations via this laser refractometer to that of well-established ultrasonic manometers throughout the range 100 Pa to 180 000 Pa. The refractometer demonstrates 10-6 ṡ p reproducibility for p > 100 Pa, and this precision outperforms a manometer. We also claim the refractometer has an expanded uncertainty of U(pFP) = [(2.0 mPa)2 + (8.8 × 10-6 ṡ p)2]1/2, as realized through the properties of nitrogen gas; we argue that a transfer of the pascal to p < 1 kPa using a laser refractometer is more accurate than the current primary realization.

  16. Carbon foam derived from pitches modified with mineral acids by a low pressure foaming process

    Energy Technology Data Exchange (ETDEWEB)

    Tsyntsarski, B.; Petrova, B.; Budinova, T.; Petrov, N.; Krzesinska, M.; Pusz, S.; Majewska, J.; Tzvetkov, P. [Bulgarian Academy of Science, Sofia (Bulgaria). Inst. of Organic Chemistry

    2010-10-15

    Carbon foams with an anisotropic texture and high mechanical strength were produced using precursors obtained after thermo-oxidation treatment of commercial coal-tar pitch with H{sub 2}SO{sub 4} and HNO{sub 3}. The investigations of the relation between the properties of the precursor and the structure of obtained foam indicate, that the composition and softening point of the pitch precursor significantly affect the foaming process, foam structure and foam mechanical strength. The composition and properties of the modified pitches allow foam formation at relatively low pressure and fast heating rate during the foaming process without a stabilization treatment. The foaming process of pitch-based carbon foams, pretreatment of the precursors, and the properties of resultant foams are discussed in this paper.

  17. Time-zero fission-fragment detector based on low-pressure multiwire proportional chambers

    CERN Document Server

    Assamagan, Ketevi A; Bayatyan, G L; Carlini, R; Danagulyan, S; Eden, T; Egiyan, K; Ent, R; Fenker, H; Gan, L; Gasparian, A; Grigoryan, N K; Greenwood, Z; Gueye, P; Hashimoto, O; Johnston, K; Keppel, C; Knyazyan, S; Majewski, S; Margaryan, A; Margaryan, Yu L; Marikian, G G; Martoff, J; Mkrtchyan, H G; Parlakyan, L; Sato, Y; Sawafta, R; Simicevic, N; Tadevosyan, V; Takahashi, T; Tang, L; Vartanian, G S; Vulcan, W; Wells, S; Wood, S

    1999-01-01

    A time-zero fission fragment (FF) detector, based on the technique of low-pressure multiwire proportional chambers (LPMWPC), has been designed and constructed for the heavy hypernuclear lifetime experiment (E95-002) at Thomas Jefferson National Accelerator Facility. Its characteristics and the method of time-zero reconstruction were investigated using fission fragments from a sup 2 sup 5 sup 2 Cf spontaneous fission source. The influence of the ionization energy loss was also studied. It is shown that Heptane, Hexane, and Isobutane gases at a pressure of 1-2 Torr are all suitable for such a FF detector. As desired by experiment, a timing resolution of about 200 ps (FWHM) for a chamber size of 21x21 cm sup 2 was achieved.

  18. Low-pressure water vapour plasma treatment of surfaces for biomolecules decontamination

    Science.gov (United States)

    Fumagalli, F.; Kylián, O.; Amato, L.; Hanuš, J.; Rossi, F.

    2012-04-01

    Decontamination treatments of surfaces are performed on bacterial spores, albumin and brain homogenate used as models of biological contaminations in a low-pressure, inductively coupled plasma reactor operated with water-vapour-based gas mixtures. It is shown that removal of contamination can be achieved using pure H2O or Ar/H2O mixtures at low temperatures with removal rates comparable to oxygen-based mixtures. Particle fluxes (Ar+ ions, O and H atomic radicals and OH molecular radicals) from water vapour discharge are measured by optical emission spectroscopy and Langmuir probe under several operating conditions. Analysis of particle fluxes and removal rates measurements illustrates the role of ion bombardment associated with O radicals, governing the removal rates of organic matter. Auxiliary role of hydroxyl radicals is discussed on the basis of experimental data. The advantages of a water vapour plasma process are discussed for practical applications in medical devices decontamination.

  19. Monte Carlo Simulation of Laser-Ablated Particle Splitting Dynamic in a Low Pressure Inert Gas

    Science.gov (United States)

    Ding, Xuecheng; Zhang, Zicai; Liang, Weihua; Chu, Lizhi; Deng, Zechao; Wang, Yinglong

    2016-06-01

    A Monte Carlo simulation method with an instantaneous density dependent mean-free-path of the ablated particles and the Ar gas is developed for investigating the transport dynamics of the laser-ablated particles in a low pressure inert gas. The ablated-particle density and velocity distributions are analyzed. The force distributions acting on the ablated particles are investigated. The influence of the substrate on the ablated-particle velocity distribution and the force distribution acting on the ablated particles are discussed. The Monte Carlo simulation results approximately agree with the experimental data at the pressure of 8 Pa to 17 Pa. This is helpful to investigate the gas phase nucleation and growth mechanism of nanoparticles. supported by the Natural Science Foundation of Hebei Province, China (No. A2015201166) and the Natural Science Foundation of Hebei University, China (No. 2013-252)

  20. Pyrene measurements in sooting low pressure methane flames by jet-cooled laser-induced fluorescence.

    Science.gov (United States)

    Wartel, M; Pauwels, J-F; Desgroux, P; Mercier, X

    2011-12-15

    This paper presents in detail the study we carried out concerning the pyrene measurement by jet-cooled laser-induced fluorescence (JCLIF) in different sooting low pressure methane flames. The aim of this paper is both to demonstrate the potentialities of this technique for the measurement of such moderately sized polycyclic aromatic hydrocarbons under sooting flame conditions and to provide new experimental data for the understanding and the development of chemical models of the soot formation processes. Several concentration profiles of pyrene measured in different sooting flame (various pressure and equivalence ratio) are presented. The validation of the JCLIF method for pyrene measurements is explained in detail as well as the calibration procedure, based on the standard addition method, which has been implemented for the quantification of the concentration profiles. Sensitivity lower than 1 ppb was obtained for the measurement of this species under sooting flame conditions.

  1. Erosion study of final stage blading of low pressure steam turbines

    Science.gov (United States)

    Dehouve, J.; Nardin, P.; Zeghmati, M.

    1999-04-01

    In order to increase our knowledge of erosion phenomena, the Steam Turbine Groupe (STG) of ALSTOM has been using an erosion test facility in the C.R.T.V. (Centre de Recherche Turbines à Vapeur). This test facility simulates erosion in low pressure steam turbine cylinders in order to compare the erosion resistance of various blade materials (12% chromium steel, titanium alloys, etc.) and their protection (superficial hardening, coatings, etc.). This test facility also allows us to understand the mechanism causing damage at a macroscopic level (impact energy of the droplets and the loss of eroded volume) and at a microscopic level (residual stress and metallurgic analysis) and therefore to determine an evolution law of material surface damage. In this paper, the behaviour of the materials (12% chromium steel and titanium alloys), which has been analysed by image production measurement methods, will be presented according to different impact velocities.

  2. Performance and control study of a low-pressure-ratio turbojet engine for a drone aircraft

    Science.gov (United States)

    Seldner, K.; Geyser, L. C.; Gold, H.; Walker, D.; Burgner, G.

    1972-01-01

    The results of analog and digital computer studies of a low-pressure-ratio turbojet engine system for use in a drone vehicle are presented. The turbojet engine consists of a four-stage axial compressor, single-stage turbine, and a fixed area exhaust nozzle. Three simplified fuel schedules and a generalized parameter fuel control for the engine system are presented and evaluated. The evaluation is based on the performance of each schedule or control during engine acceleration from a windmill start at Mach 0.8 and 6100 meters to 100 percent corrected speed. It was found that, because of the higher acceleration margin permitted by the control, the generalized parameter control exhibited the best dynamic performance.

  3. Oxygen transport membrane based advanced power cycle with low pressure synthesis gas slip stream

    Energy Technology Data Exchange (ETDEWEB)

    Kromer, Brian R.; Litwin, Michael M.; Kelly, Sean M.

    2016-09-27

    A method and system for generating electrical power in which a high pressure synthesis gas stream generated in a gasifier is partially oxidized in an oxygen transport membrane based reactor, expanded and thereafter, is combusted in an oxygen transport membrane based boiler. A low pressure synthesis gas slip stream is split off downstream of the expanders and used as the source of fuel in the oxygen transport membrane based partial oxidation reactors to allow the oxygen transport membrane to operate at low fuel pressures with high fuel utilization. The combustion within the boiler generates heat to raise steam to in turn generate electricity by a generator coupled to a steam turbine. The resultant flue gas can be purified to produce a carbon dioxide product.

  4. The advantages of Low Pressure Carburizing in the Heat Treatment Subcontracting Business

    Institute of Scientific and Technical Information of China (English)

    Guy PRUNEL; Bruno STAUDER

    2004-01-01

    Low Pressure Carburizing (LPC) was introduced in the 90's in the western Europe Heat Treatment business,mainly for in-house applications where it was especially appreciated for carburizing of transmission parts. However the success of the LPC units installed for gears carburizing in the automotive industry has hindered the development of the process in other fields - like subcontracting business -, where its advantages deserve to be enlightened.After a brief review of the principle of the process, the interest of its classical application to transmission parts is described,underlining peculiarly the reduction of the distortion observed when LPC is associated with high pressure gas quenching.Then the less-known advantages of the LPC process, like the high accuracy and reproducibility of the results, the modeling possibility and the simulation easiness, the case-depth uniformity and the full flexibility of the units are considered,showing how they can be beneficial to subcontracting business.

  5. Optimization Design and Experimental Study of Low-Pressure Axial Fan with Forward-Skewed Blades

    Directory of Open Access Journals (Sweden)

    Li Yang

    2007-01-01

    Full Text Available This paper presents an experimental study of the optimization of blade skew in low pressure axial fan. Using back propagation (BP neural network and genetic algorithm (GA, the optimization was performed for a radial blade. An optimized blade is obtained through blade forward skew. Measurement of the two blades was carried out in aerodynamic and aeroacoustic performance. Compared to the radial blade, the optimized blade demonstrated improvements in efficiency, total pressure ratio, stable operating range, and aerodynamic noise. Detailed flow measurement was performed in outlet flow field for investigating the responsible flow mechanisms. The optimized blade can cause a spanwise redistribution of flow toward the blade midspan and reduce tip loading. This results in reduced significantly total pressure loss near hub and shroud endwall region, despite the slight increase of total pressure loss at midspan. In addition, the measured spectrums show that the broadband noise of the impeller is dominant.

  6. INTERNAL FLOW MECHANISM AND EXPERIMENTAL RESEARCH OF LOW PRESSURE AXIAL FAN WITH FORWARD-SKEWED BLADES

    Institute of Scientific and Technical Information of China (English)

    LI Yang; LIU Jie; OUYANG Hua; DU Zhao-Hui

    2008-01-01

    This article presents the flow mechanism analysis and experimental study of a forward-skewed impeller and a radial impeller in low pressure axial fan. The forward-skewed blade was obtained by the optimization design of the radial blade and CFD technique. Measurement of the two blades was carried out in aerodynamic and aeroacoustic performance. Compared to the radial blade, the forward-skewed blade has demonstrated the improvements in efficiency, total pressure ratio, Stable Operating Range (SOR) and less aerodynamic noise. Detailed flow measurement and computation were performed for outlet flow field for investigating the responsible flow mechanisms. The results show the forward-skewed blade can cause a spanwise redistribution of flow toward the blade mid-span and reduce tip loading. This results in reduced significantly total pressure loss near hub and shroud endwall region, despite the slight increase of total pressure loss at mid-span.

  7. Low pressure phase diagram of CeCoGe{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Mizoo, Masakazu; Nishioka, Takashi; Kato, Harukazu; Matsumura, Masahiro, E-mail: nisioka@kochi-u.ac.jp [Graduate School of Integrated Arts and Sciences, Kochi University, Kochi 780-8520 (Japan)

    2011-01-01

    We have performed measurements of the Hall magnetization and electrical resistivity on a pressure-induced antiferromagnetic heavy fermion superconductor CeCoGe{sub 3} at pressures up to {approx}1.7 GPa, which crystallizes in the tetragonal BaNiSn{sub 3}-type structure without inversion symmetry. We have clarified that five successive phase transitions appear at ambient pressure. As pressure is applied, these transitions approach one another until {approx}1.2 GPa, and then separate again. We have also found another phase transition emerges above {approx}0.5 GPa, which is consistent with a recent Co-NQR study. From these results, we propose a low pressure P-T phase diagram, which contains at least eight ordered phases below {approx}2 GPa. This phase diagram is consistent with a recent reported high pressure phase diagram.

  8. Turbulent kinetic energy balance measurements in the wake of a low-pressure turbine blade

    Energy Technology Data Exchange (ETDEWEB)

    Sideridis, A. [Laboratory of Fluid Mechanics and Turbomachinery, Department of Mechanical Engineering, Aristotle University of Thessaloniki, 54124 Thessaloniki (Greece); Yakinthos, K., E-mail: kyros@eng.auth.g [Laboratory of Fluid Mechanics and Turbomachinery, Department of Mechanical Engineering, Aristotle University of Thessaloniki, 54124 Thessaloniki (Greece); Goulas, A. [Laboratory of Fluid Mechanics and Turbomachinery, Department of Mechanical Engineering, Aristotle University of Thessaloniki, 54124 Thessaloniki (Greece)

    2011-02-15

    The turbulent kinetic energy budget in the wake generated by a high lift, low-pressure two-dimensional blade cascade of the T106 profile was investigated experimentally using hot-wire anemometry. The purpose of this study is to examine the transport mechanism of the turbulent kinetic energy and provide validation data for turbulence modeling. Point measurements were conducted on a high spatial resolution, two-dimensional grid that allowed precise derivative calculations. Positioning of the probe was achieved using a high accuracy traversing mechanism. The turbulent kinetic energy (TKE) convection, production, viscous diffusion and turbulent diffusion were all obtained directly from experimental measurements. Dissipation and pressure diffusion were calculated indirectly using techniques presented and validated by previous investigators. Results for all terms of the turbulent kinetic energy budget are presented and discussed in detail in the present work.

  9. Propagation of light in low pressure ionised and atomic hydrogen. Application to astrophysics

    CERN Document Server

    Moret-Bailly, J

    2003-01-01

    The "Impulsive Stimulated Raman Scattering" (ISRS) performed using ultrashort laser pulses shifts the light frequencies. Tried using ordinary incoherent light, it keeps its qualitative properties except the nonlinearity due to the power of the laser pulses. The relative frequency shifts of the "Coherent Raman Effect on Incoherent Light" (CREIL) which is obtained do not depend on the intensity and, in a first approximation, on the frequency of the light. As CREIL does not blur the images and the spectra, its shifts may be confused with Doppler shifts. ISRS and CREIL are parametric effects which do not excite the matter, transferring energy from hot beams to cold beams; for CREIL, the cold light is thermal radiation which is heated. CREIL requires low pressure gases acting as catalysts. These gases must have Raman transitions in the radiofrequencies range: for instance H2+ or excited atomic hydrogen in a magnetic field. The spectral lines resulting from a simultaneous absorption (or emission) and CREIL have a w...

  10. Research and Evaluation for Passive Safety System in Low Pressure Reactor

    Directory of Open Access Journals (Sweden)

    Peng Chuanxin

    2015-01-01

    Full Text Available Low pressure reactor is a small size advanced reactor with power of 180 MWt, which is under development at Nuclear Power Institute of China. In order to assess the ability and feasibility of passive safety system, several tests have been implemented on the passive safety system (PSS test facility. During the LOCA and SBO accident, the adequate core cooling is provided by the performance of passive safety system. In addition the best-estimate thermal hydraulic code, CATHARE V2.1, has been assessed against cold leg LOCA test. The calculation results show that CATHARE is in a satisfactory agreement with the test for the steady state and transient test.

  11. Research program: The investigation of heat transfer and fluid flow at low pressure

    Science.gov (United States)

    El-Genk, M. S.; Philbin, J. S.; Foushee, F. C.

    1986-04-01

    This paper gives an overview of a multiyear joint research program being conducted at the University of New Mexico (UNM) with support from Sandia National Laboratories and GA Technologies. This research focuses on heat removal and fluid dynamics in flow regimes characterized by low pressure and low Reynolds number. The program was motivated by a desire to characterize and analyze cooling in a broad class of TRIGA-type reactors under: (1) typical operating conditions, (2) anticipated, new operating regimes, and (3) postulated accident conditions. It has also provided experimental verification of analytical tools used in design analysis. The paper includes descriptions of the UNM thermal-hydraulics test facility and the experimental test sections. During the first two years experiments were conducted using single, electrically heated rod in water and air annuli. This configuration provides an observable and serviceable simulation of a fuel rod and its coolant channel.

  12. Principles and practice of low pressure-expendable pattern casting process for magnesium alloys

    Institute of Scientific and Technical Information of China (English)

    LI Ji-qiang; FAN Zi-tian; WU He-bao; DONG Xuan-pu; ZHANG Da-fu; HUANG Nai-yu

    2006-01-01

    A newly developed low-pressure expendable pattern casting (LP-EPC) process was introduced and its basic pnnciples or effect factors were further analyzed. According to theoretical calculation and experimental results, the major casting parameters that are of great and critical importance on the process include pressure and flux of filling gas, decomposition characteristic and density of foam pattern,thickness and permeability of coating, pouring temperature, vacuum degree and their combination. Most of casting defects can be effectively avoided by choosing the suitable parameters. The success achieved in pouring motor housing and exhaust manifold castings demonstrates the advantages of LP-EPC process in the production of high-complicated castings with high dimension accuracy.

  13. Numerical simulation and optimization of Al alloy cylinder body by low pressure die casting

    Institute of Scientific and Technical Information of China (English)

    Mi Guofa; Liu Yanlei; Zhao Hengtao; Fu Hengzhi

    2008-01-01

    Shrinkage defects can be formed easily at critical location during low pressure die casting(LPDC)of aluminum alloy cylinder body.It has harmful effect on the products.Mold filling and solidification process of a cylinder body was simulated by using of Z-CAST software.The casting method was Improved based on the simulation results.In order to create eriective feeding passage,the structure of casting was modified by changing the location of strengthening ribs at the bottom,without causing any adverse effect on the part's performance.Inserting copper billet at suitable Iocation of the die is a valid way to create suitable solidification sequence that is beneficial to the feeding.Using these methods.the shrinkage defect was completely eliminated at the critical location.

  14. Oxygen transport membrane based advanced power cycle with low pressure synthesis gas slip stream

    Science.gov (United States)

    Kromer, Brian R.; Litwin, Michael M.; Kelly, Sean M.

    2016-09-27

    A method and system for generating electrical power in which a high pressure synthesis gas stream generated in a gasifier is partially oxidized in an oxygen transport membrane based reactor, expanded and thereafter, is combusted in an oxygen transport membrane based boiler. A low pressure synthesis gas slip stream is split off downstream of the expanders and used as the source of fuel in the oxygen transport membrane based partial oxidation reactors to allow the oxygen transport membrane to operate at low fuel pressures with high fuel utilization. The combustion within the boiler generates heat to raise steam to in turn generate electricity by a generator coupled to a steam turbine. The resultant flue gas can be purified to produce a carbon dioxide product.

  15. The effects of plasma inhomogeneity on the nanoparticle coating in a low pressure plasma reactor

    Science.gov (United States)

    Pourali, N.; Foroutan, G.

    2015-10-01

    A self-consistent model is used to study the surface coating of a collection of charged nanoparticles trapped in the sheath region of a low pressure plasma reactor. The model consists of multi-fluid plasma sheath module, including nanoparticle dynamics, as well as the surface deposition and particle heating modules. The simulation results show that the mean particle radius increases with time and the nanoparticle size distribution is broadened. The mean radius is a linear function of time, while the variance exhibits a quadratic dependence. The broadening in size distribution is attributed to the spatial inhomogeneity of the deposition rate which in turn depends on the plasma inhomogeneity. The spatial inhomogeneity of the ions has strong impact on the broadening of the size distribution, as the ions contribute both in the nanoparticle charging and in direct film deposition. The distribution width also increases with increasing of the pressure, gas temperature, and the ambient temperature gradient.

  16. Development of water soluble binder systems for low pressure injection molding of alumina

    Energy Technology Data Exchange (ETDEWEB)

    Bakan, H.I.; Gunes, M. [TUBITAK-MRC Materials and Chemical Technologies Research Inst., Kocaeli (Turkey)

    2004-07-01

    Low pressure injection molding of alumina powder using a water-soluble binder system has been carried out successfully. The water-soluble based binder system consisted of poly (2-ethyl-2-oxaline), low density polyethylene and stearic acid. The critical powder loading of the binder-powder mixture was determined based on torque rheometry experiments. The rheological properties of the powder-binder mixture were investigated systematically. The binder system used provides satisfactory mixture stability, excellent mouldability and reasonably fast water leaching and thermal debinding rates. The water-soluble constituent, poly (2-ethyl-2-oxaline), was removed by leaching in convecting water at 60 C within 6 hour. The remaining binder constituents were thermally removed during heating to 450 C. Sintering of the parts was conducted at 1550 C for an hour in air. (orig.)

  17. Characterization of the large area plane-symmetric low-pressure DC glow discharge

    Science.gov (United States)

    Avtaeva, S.; Gorokhovsky, V.; Myers, S.; Robertson, S.; Shunko, E.; Zembower, Z.

    2016-10-01

    Electron density and temperature as well as nitrogen dissociation degree in the low-pressure (10-50 mTorr) large area plane-symmetric DC glow discharge in Ar-N2 mixtures are studied by probes and spectral methods. Electron density measured by a hairpin probe is in good agreement with that derived from the intensity ratio of the N2 2nd positive system bands IC , 1 - 3/IC , 0 - 2 and from the intensity ratio of argon ions and atom lines IArII/IArI, while Langmuir probe data provides slightly higher values of electron density. Electron density in the low-pressure DC glow discharge varies with the discharge conditions in the limits of 108-1010 cm- 3. The concept of electron temperature can be used in low-pressure glow discharges with reservations. The intensity ratio of (0-0) vibrational bands of N2 1st negative and 2nd positive systems I391.4/I337.1 exhibits the electron temperature of 1.5-2.5 eV when argon fraction in the mixture is higher than nitrogen fraction and this ratio quickly increases with nitrogen fraction up to 10 eV in pure nitrogen. The electron temperature calculated from Langmuir probe I-V characteristics assuming a Maxwellian EEDF, gives Te 0.3-0.4 eV. In-depth analysis of the EEDF using the second derivative of Langmuir probe I-V characteristics shows that in a low-pressure glow discharge the EEDF is non-Maxwellian. The EEDF has two populations of electrons: the main background non-Maxwellian population of ;cold; electrons with the mean electron energy of 0.3-0.4 eV and the small Maxwellian population of ;hot; electrons with the mean electron energy of 1.0-2.5 eV. Estimations show that with electron temperature lower than 1 eV the rate of the direct electron impact ionization of N2 is low and the main mechanism of N2 ionization becomes most likely Penning and associative ionization. In this case, assumptions of the intensity ratio IN2+ , 391/IN2 , 337 method are violated. In the glow discharge, N2 dissociation degree reaches about 7% with the argon

  18. Simulation of rarefied low pressure RF plasma flow around the sample

    Science.gov (United States)

    Zheltukhin, V. S.; Shemakhin, A. Yu

    2017-01-01

    The paper describes a mathematical model of the flow of radio frequency plasma at low pressure. The hybrid mathematical model includes the Boltzmann equation for the neutral component of the RF plasma, the continuity and the thermal equations for the charged component. Initial and boundary conditions for the corresponding equations are described. The electron temperature in the calculations is 1-4 eV, atoms temperature in the plasma clot is (3-4) • 103 K, in the plasma jet is (3.2-10) • 102 K, the degree of ionization is 10-7-10-5, electron density is 1015-1019 m-3. For calculations plasma parameters is developed soft package on C++ program language, that uses the OpenFOAM library package. Simulations for the vacuum chamber in the presence of a sample and the free jet flow were carried out.

  19. Effects of feed solution chemistry on low pressure reverse osmosis filtration of cesium and strontium

    Energy Technology Data Exchange (ETDEWEB)

    Ding, Shiyuan, E-mail: dingshiyuan@bnu.edu.cn [State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, No. 19, Xinjiekouwai Street, Haidian District, Beijing 100875 (China); Yang, Yu, E-mail: yangyu@bnu.edu.cn [State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, No. 19, Xinjiekouwai Street, Haidian District, Beijing 100875 (China); Huang, Haiou, E-mail: huanghaiou@bnu.edu.cn [State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, No. 19, Xinjiekouwai Street, Haidian District, Beijing 100875 (China); Liu, Hengchen, E-mail: 799599501@qq.com [State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, No. 19, Xinjiekouwai Street, Haidian District, Beijing 100875 (China); Hou, Li-an, E-mail: houlian678@hotmail.com [State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, No. 19, Xinjiekouwai Street, Haidian District, Beijing 100875 (China); Xi’an High-Tech Institute, No. 2, Tongxin Street, Baqiao District, Xi’an 710025 (China)

    2015-08-30

    Highlights: • A low pressure spiral wound RO membrane can reject Cs and Sr efficiently. • The rejection of Cs and Sr is dependent on feed pH and co-existing ions. • Donnan exclusion and electrostatic interaction govern the rejection of Cs and Sr. • The differences of filtration mechanism were influenced by the size of ions. • Sr could strengthen the irreversible membrane fouling resistance with HA. - Abstract: The objective of this study was to identify the removal mechanisms of radionuclides by reverse osmosis (RO) membranes under conditions relevant to full-scale water treatment. For this purpose, the effects of feed solution chemistry on the removal of Cs and Sr by a low pressure RO system was investigated by systematically varying membrane surface charge, ionic composition, and organic matter concentrations. The results showed that the effects of solution chemistry on the filtration of Cs and Sr were related to their hydrated ionic radius, resulting in the predominance of the Donnan’s effect and electrostatic interactions, respectively. Consequently, the rejection of Cs increased more pronouncedly than Sr with the increases of feed concentration. Due to the Donnan’s effect, different anions decreased the rejection of Cs to different extents in accordance to the order of anions’ radii as SO{sub 4}{sup 2−} > Cl{sup −} > NO{sub 3}{sup −} > F{sup −}. The variations in Sr rejection were influenced by the electrostatic interactions between Sr{sup 2+} and the membrane. In addition, humic acid (HA) lowered the rejection of Cs and caused significant membrane flux decline, but did not change the rejection of Sr. Sr also aggravated HA fouling of the membrane.

  20. Effects of Alternate Leading Edge Cutback on the Space Shuttle Main Engine Low Pressure Fuel Pump

    Science.gov (United States)

    Mulder, Andrew; Skelley, Stephen

    2016-01-01

    A higher order cavitation oscillation observed in the SSME low pressure fuel pump has been eliminated in water flow testing of a modified subscale replica of the inducer. The low pressure pump was modified by removing the outboard sections of two opposing blades of the four-bladed inducer, blending the "cutback" regions into the blades at the leading edge and tip, and removing material on the suction sides to decrease the exposed leading edge thickness. The leading edge tips of the cutback blades were moved approximately 25 degrees from their previous locations, thereby increasing one blade to blade spacing, decreasing the second, while simultaneously moving the cutback tips downstream. The test was conducted in MSFC's inducer test loop at scaled operating conditions in degassed and filtered water. In addition to eliminating HOC across the entire scaled operating regime, rotating cavitation was suppressed while the range of both alternate blade and asymmetric cavitation were increased. These latter phenomena, and more significantly, the shifts between these cavitation modes also resulted in significant changes to the head coefficient at low cavitation numbers. Reverse flow was detected at a slightly larger flow coefficient with the cutback inducer and suction capability was reduced by approximately 1 velocity head at and above approximately 90% of the reference flow coefficient. These performance changes along with more intense reverse flow are consistent with poor flow area management and increased incidence in the cutback region. Although the test demonstrated that the inducer modification was successful at eliminating the higher order cavitation across the entire scaled operating regime, different, previously unobserved, cavitation oscillations were introduced and significant performance penalties were imposed.