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Sample records for acute stent recoil

  1. Comparison of Acute Recoil between Bioabsorbable Poly-L-lactic Acid XINSORB Stent and Metallic Stent in Porcine Model

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    Yizhe Wu

    2012-01-01

    Full Text Available Objective. To investigate acute recoil of bioabsorbable poly-L-lactic acid (PLLA stent. Background. As newly developed coronary stent, bioabsorbable PLLA stent still encountered concern of acute stent recoil. Methods. Sixteen minipigs were enrolled in our study. Eight PLLA XINSORB stents (Weite Biotechnology Co., Ltd., China and eight metallic stents (EXCEL, Jiwei Co., Ltd. China were implanted into coronary arteries. Upon quantitative coronary angiography analysis, acute absolute recoil was defined as the difference between mean diameter of inflated balloon (X and mean lumen diameter of stent immediately after deployment (Y, while acute percent recoil was defined as (X−Y/X and expressed as a percentage. Intravascular ultrasound (IVUS was performed immediately after implantation and 24 hours later to compare cross-sectional area (CSA between two groups and detect stent malapposition or collapse. Results. Acute absolute recoil in XINSORB and EXCEL was 0.02±0.13 mm and −0.08±0.08 mm respectively (P=0.19. Acute percent recoil in XINSORB and EXCEL was 0.66±4.32% and −1.40±3.83%, respectively (P=0.45. CSA of XINSORB was similar to that of EXCEL immediately after implantation, so was CSA of XINSORB at 24-hours followup. Within XINSORB group, no difference existed between CSA after implantation and CSA at 24-hours followup. No sign of acute stent malapposition was detected by IVUS. Conclusions. The acute stent recoil of XINSORB is similar to that of EXCEL. No acute stent malapposition or collapse appeared in both kinds of stent. This preclinical study was designed to provide preliminary data for future studies of long-term efficacy and safety of XINSORB stent.

  2. Comparison of in vivo acute stent recoil between the bioabsorbable everolimus-eluting coronary stent and the everolimus-eluting cobalt chromium coronary stent: insights from the ABSORB and SPIRIT trials

    DEFF Research Database (Denmark)

    Tanimoto, Shuzou; Serruys, Patrick W; Thuesen, Leif

    2007-01-01

    the antiproliferative drug, everolimus, and expected to be totally metabolized and absorbed in the human body. Because the BVS is made from polymer, it may have more acute recoil than metallic stents in vivo. METHODS: A total of 54 patients, who underwent elective stent implantation for single de novo native coronary......OBJECTIVES: This study sought to evaluate and compare in vivo acute stent recoil of a novel bioabsorbable stent and a metallic stent. BACKGROUND: The bioabsorbable everolimus-eluting coronary stent (BVS) is composed of a poly-L-lactic acid backbone, coated with a bioabsorbable polymer containing...

  3. Acute stent thrombosis after bifurcation stenting with the crush technique visualized with 64-slice computed tomography

    DEFF Research Database (Denmark)

    Kristensen, T.S.; Engstrom, T.; Kofoed, Klaus Fuglsang

    2008-01-01

    Acute stent thrombosis remains a potential complication after stent implantation. With the introduction of electrocardiographic gated multidetector row computed tomography (MDCT), a new nonnvasive imaging modality has become available that may contribute to the detection of complications after...

  4. Acute stent thrombosis after primary percutaneous coronary intervention

    DEFF Research Database (Denmark)

    Clemmensen, Peter; Wiberg, Sebastian; Van't Hof, Arnoud;

    2015-01-01

    OBJECTIVES: This study sought to determine clinical, procedural, and treatment factors associated with acute stent thrombosis (AST) in the EUROMAX (European Ambulance Acute Coronary Syndrome Angiography) trial. BACKGROUND: Bivalirudin started during transport for primary percutaneous coronary int...

  5. Stent-based mechanical thrombectomy in acute basilar artery occlusion.

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    Cohen, José E; Leker, Ronen R; Moscovici, Samuel; Attia, Moshe; Itshayek, Eyal

    2011-12-01

    Stent-based mechanical thrombectomy was recently proposed as an effective alternative to other mechanical techniques to achieve recanalization of large-vessel embolic occlusions in the anterior circulation. To our knowledge, there are no reports of the use of this technique in acute basilar artery occlusion (ABAO). We present a patient with complete endovascular recanalization of ABAO using a stent-based thrombectomy technique. Advantages and limitations of this technique in the management of ABAO are discussed. The stent-thrombectomy technique is promising, and will need further evaluation in posterior circulation stroke.

  6. Rescue coronary stenting in acute myocardial infarction

    Science.gov (United States)

    Barbieri, Enrico; Meneghetti, Paolo; Molinari, Gionata; Zardini, Piero

    1996-01-01

    Failed rescue coronary angioplasty is a high risk situation because of high mortality. Coronary stent has given us the chance of improving and maintaining the patency of the artery. We report our preliminary experience of rescue stenting after unsuccessful coronary angioplasty.

  7. Primary stenting as emergency therapy in acute basilar artery occlusion

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    Spreer, Joachim; Arnold, Sebastian; Klisch, Joachim; Schumacher, Martin [Section of Neuroradiology, University Hospital Freiburg, Breisacher Strasse 64, 79106 Freiburg (Germany); Els, Thomas; Hetzel, Andreas; Huppertz, Hans-Juergen; Oehm, Eckhardt [Department of Neurology, University Hospital Freiburg, Freiburg (Germany)

    2002-09-01

    In three patients with acute occlusion of the basilar artery intra-arterial fibrinolysis resulted in only partial recanalization and revealed severe stenosis as the underlying cause. Application of micro-stents without previous dilatation resulted in vessel re-opening. Two patients had an excellent clinical outcome. One patient died 10 days after the stroke due to brainstem infarction. Emergency primary stent application may improve the outcome in acute basilar artery occlusion, if intra-arterial thrombolysis fails to re-establish a sufficient flow. (orig.)

  8. One year clinical follow up of paclitaxel eluting stents for acute myocardial infarction compared with sirolimus eluting stents

    NARCIS (Netherlands)

    S.H. Hofma (Sjoerd); M. Valgimigli (Marco); C.A.G. van Mieghem (Carlos); P.J. de Feyter (Pim); P.W.J.C. Serruys (Patrick); W.J. van der Giessen (Wim); P.P.T. de Jaegere (Peter); E.S. Regar (Eveline); G. Sianos (Georgios); J. Aoki (Jiro); G.A. Rodriguez-Granillo (Gaston); E.P. McFadden (Eugene); A.T.L. Ong (Andrew); R.T. van Domburg (Ron)

    2005-01-01

    textabstractOBJECTIVE: To compare clinical outcome of paclitaxel eluting stents (PES) versus sirolimus eluting stents (SES) for the treatment of acute ST elevation myocardial infarction. DESIGN AND PATIENTS: The first 136 consecutive patients treated exclusively with PES in the setting of primary pe

  9. Acute Carotid Artery Stent Thrombosis Due to Dual Antiplatelet Resistance

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    Köklü, Erkan, E-mail: drerkankoklu@gmail.com; Arslan, Şakir; Yüksel, İsa Öner; Bayar, Nermin [Antalya Education and Research Hospital, Clinic of Cardiology (Turkey); Koç, Pınar [Antalya Education and Research Hospital, Clinic of Radiology (Turkey)

    2015-08-15

    Carotid artery stenting (CAS) is a revascularization modality that is an alternative to carotid endarterectomy. The efficacy of CAS in primary and secondary prevention from ischemic stroke has been demonstrated in various trials. Acute thrombosis of CAS is a rare complication that can lead to dramatic and catastrophic consequences. We discuss a case of acute CAS thrombosis in a patient who had previously undergone successful CAS. CAS was performed in a 73-year-old man who had had dysarthria lasting 2 weeks with 95 % stenosis in his left internal carotid artery. An acute cerebrovascular event resulting in right-sided hemiplegia developed 24 h after the procedure. Computed tomographic carotid angiography revealed complete occlusion of the stent with thrombus. The cause of stent thrombosis was thought to be antiaggregant resistance to both acetylsalicylic acid and clopidogrel. The most important cause of acute CAS thrombosis is inadequate or ineffective antiaggregant therapy. Evaluating patients who are candidates for CAS for acetylsalicylic acid and clopidogrel resistance may preclude this complication.

  10. Acute clinical and angiographic results with the new AVE Micro coronary stent in bailout management.

    NARCIS (Netherlands)

    Y. Ozaki (Yukio); D.T.J. Keane (David); P.N. Ruygrok (Peter); S. Stertzer (Simon); P.W.J.C. Serruys (Patrick); P.J. de Feyter (Pim)

    1995-01-01

    textabstractTo determine the feasibility and safety of development of this new stent, we deployed 28 AVE Micro stents in 23 native coronary artery lesions in 20 patients who developed acute or threatened closure after balloon angioplasty (BA). Ten stents were deployed in the left anterior descending

  11. "Knot Stent": An Unusual Cause of Acute Renal Failure in Solitary Kidney

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    Kamal Moufid

    2012-01-01

    Full Text Available The insertion of indwelling ureteric stents is a routine procedure in urology practice. Complications secondary to the insertion of these stents have also increased, such as stent encrustation, stent fragmentation, stone formation, and recurrent urinary tract infections. Knot formation within the renal pelvis or in the coiled portion of the ureteral stent is an extremely rare condition, with less than 15 cases reported in literature. The authors report a rare case of knotted stent, complicated by an obstructive acute renal failure and urosepsis, in a patient with a solitary functioning kidney.

  12. Life-threatening Cerebral Edema Caused by Acute Occlusion of a Superior Vena Cava Stent

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    Sofue, Keitaro, E-mail: keitarosofue@yahoo.co.jp; Takeuchi, Yoshito, E-mail: yotake62@qg8.so-net.ne.jp; Arai, Yasuaki, E-mail: arai-y3111@mvh.biglobe.ne.jp [National Cancer Center Hospital, Department of Diagnostic Radiology (Japan); Sugimura, Kazuro, E-mail: sugimura@med.kobe-u.ac.jp [Kobe University, Department of Radiology, Graduate School of Medicine (Japan)

    2013-02-15

    A71-year-old man with advanced lung cancer developed a life-threatening cerebral edema caused by the acute occlusion of a superior vena cava (SVC) stent and was successfully treated by an additional stent placement. Although stent occlusion is a common early complication, no life-threatening situations have been reported until now. Our experience highlights the fact that acute stent occlusion can potentially lead to the complete venous shutdown of the SVC, resulting in life-threatening cerebral edema, after SVC stent placement. Immediate diagnosis and countermeasures are required.

  13. Combined use of transmyocardial stents with gene therapy in the treatment of acute myocardial infarction

    Institute of Scientific and Technical Information of China (English)

    王永武

    2006-01-01

    Objective To determine the efficacy of combined use of transmyocardial stent with gene therapy to treat acute myocardial infarction in porcine model. Methods 24 Chinese mini swines have been devided into 4 groups randomly: group myocardial infarction (group MI n1 = 6), group transmyocardial stent (group ST n2 = 6) , group vascular endothelial growth factor (group VEGF n3 = 6) , group transmyocardial stent and VEGF (group ST + VEGF n4 = 6). In group MI,acute myocardial infarc-

  14. Impact of rivaroxaban on stent thrombosis and secondary prevention of cardiovascular events in acute coronary syndrome

    Directory of Open Access Journals (Sweden)

    Krohn-Grimberghe M

    2014-05-01

    Full Text Available Marvin Krohn-Grimberghe, Christoph Bode, Constantin von zur MuhlenDepartment of Cardiology and Angiology I, Heart Center, University of Freiburg, GermanyAbstract: Angioplasty and stent implantation have greatly improved the outcome of patients with acute coronary syndrome. However, stents come with the risk of stent thrombosis, which is associated with a high rate of revascularization, myocardial infarction, and death. The inhibition of factor Xa due to rivaroxaban leads to an interruption of the intrinsic as well as the extrinsic coagulation pathway, which reduces thrombus formation as a potential mechanism to diminish the rate of stent thrombosis. In this review, we evaluate the role of rivaroxaban in the prevention of stent thrombosis and its general role in patients with acute coronary syndrome.Keywords: Rivaroxaban, stent thrombosis, acute coronary syndrome, secondary prevention

  15. Stent-graft repair for acute traumatic thoracic aortic rupture.

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    Neuhauser, B; Czermak, B; Jaschke, W; Waldenberger, P; Fraedrich, G; Perkmann, R

    2004-12-01

    Traumatic rupture of the thoracic aorta is potentially life-threatening and leads to death in 75 to 90 per cent of cases at the time of injury. In high-risk patients, as traumatic injuries of the aorta combine with multiple associated injuries, endoluminal repair is now reported as a promising therapeutic strategy with encouraging results. This study determined the outcome of patients with traumatic thoracic aortic injury treated endovascularly during the past 7 years at our institution. Thirteen patients, 11 males and 2 females (mean age, 39 years; range, 19-82), with traumatic rupture of the otherwise unremarkable descending aorta (10 acute, 3 chronic), out of a series of 64 endovascular thoracic stent-graft procedures, were treated by implantation of Talent (n = 8), Vanguard (n = 5), and Excluder (n = 2) self-expanding devices between January 1996 and August 2003. The immediate technical success rate was 92 per cent (12/13). One patient showed a proximal endoleak type I, which was treated successfully by an additional stent-graft procedure. Secondary success rate was 100 per cent. The mortality rate was 0 per cent. Two additional stent-graft procedures were performed due to type I endoleaks after 18 and 28 months. There was no other intervention-related morbidity or mortality during the mean follow-up time of 26.4 months' (range, 6-86). Endovascular stent-graft repair of traumatic thoracic aortic injuries is a safe, effective, and low-morbidity alternative to open thoracic surgery and has promising midterm results.

  16. ST-elevated acute myocardial infarction happening 1 month post stent implantation: late thrombosis in-stents or new lesions?

    Institute of Scientific and Technical Information of China (English)

    SONG Guang-yuan; YANG Yue-jin; XU Bo; LI Jian-jun; GAO Run-lin; QIAO Shu-bin; YUAN Jin-qing; TANG Yi-da; YOU Shi-jie; PEI Han-jun; ZHAO Zhen-yan; WANG Xi-mei; WU Yong-jian

    2009-01-01

    Background ST-elevated acute myocardial infarction (STEAMI) happening in the first month post percutaneous coronary intervention (PCI) is almost related to acute thrombosis or subacute thrombosis in-stents. This study aimed to investigate the possible causes of myocardial infarction one month later. Methods Patients who had a history of successful PCI, and received coronary angiography or re-PCI due to STEAMI were included in this study. The AMI-related lesions and previous angiographic findings such as the number of lesions, the degree of the stenosis, the type of stents and acute results of last PCI were recorded. If the AMI-related lesion was localized in-stents or at the edge of stents (distance apart from the edge <5 mm), it was defined to be late thrombosis; otherwise as a new-lesion induced AMI. Results One hundred and ninety-two patients aged 40-79 years were included in this study. New lesions, as the cause of STEAMI, were found in 144 patients (Group A, 75%), and late thrombosis in 48 patients (Group B, 25%). Almost all newly built thromboses were found at the sites of previous insignificant lesions (diameter stenosis <50%). There was a significant difference in the average time from previous PCI to AMI ((30.1+12.4) vs (20.3+11.9) months) between the two groups. Diabetes mellitus (DM) and drug-eluting stent (DES) utilization were associated with markedly higher morbidity of late thrombosis in adjusted Logistic regression (hazard ratio (HR) 3.4, 95% confidence interval (CI) 1.1-10.9 and 5.3, 95% CI 1.1-26.5). Conclusions STEAMIs happening 1 month after PCI are more likely to develop from previous insignificant lesion rupture than from late thrombosis in-stents. Moreover, DM and DES are associated with the high incidence of latethrombosis, which may indicate that intensive antiplatelet therapy should be considered in patients with diabetes.

  17. Hepatic artery stent-grafts for the emergency treatment of acute bleeding

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    Bellemann, Nadine, E-mail: nadine.bellemann@med.uni-heidelberg.de [Department of Diagnostic and Interventional Radiology, University Hospital Heidelberg, INF 110, 69120 Heidelberg (Germany); Sommer, Christof-Matthias; Mokry, Theresa; Kortes, Nikolas; Gnutzmann, Daniel; Gockner, Theresa; Schmitz, Anne [Department of Diagnostic and Interventional Radiology, University Hospital Heidelberg, INF 110, 69120 Heidelberg (Germany); Weitz, Jürgen [Department of Surgery, University Hospital Heidelberg, INF 110, 69120 Heidelberg (Germany); Department for Visceral, Thoracic and Vascular Surgery at the University Hospital, Technical University Dresden (Germany); Kauczor, Hans-Ulrich; Radeleff, Boris; Stampfl, Ulrike [Department of Diagnostic and Interventional Radiology, University Hospital Heidelberg, INF 110, 69120 Heidelberg (Germany)

    2014-10-15

    Highlights: • We report our experiences with stent-grafts for the treatment of acute hemorrhage from the hepatic artery or the stump of the gastroduodenal artery. • The technical success of stent-graft implantation was 88%. • The bleeding ceased immediately after stent-graft implantation in 88%. • The complication rate was 21%. - Abstract: Purpose: We evaluated the technical success and clinical efficacy of stent-graft implantation for the emergency management of acute hepatic artery bleeding. Methods: Between January 2010 and July 2013, 24 patients with hemorrhage from the hepatic artery were scheduled for emergency implantation of balloon expandable stent-grafts. The primary study endpoints were technical and clinical success, which were defined as successful stent-graft implantation with sealing of the bleeding site at the end of the procedure, and cessation of clinical signs of hemorrhage. The secondary study endpoints were complications during the procedure or at follow-up and 30-day mortality rate. Results: In 23 patients, hemorrhage occurred after surgery, and in one patient hemorrhage occurred after trauma. Eight patients had sentinel bleeding. In most patients (n = 16), one stent-graft was implanted. In six patients, two overlapping stent-grafts were implanted. The stent-grafts had a target diameter between 4 mm and 7 mm. Overall technical success was 88%. The bleeding ceased after stent-graft implantation in 21 patients (88%). The mean follow-up was 137 ± 383 days. In two patients, re-bleeding from the hepatic artery occurred during follow-up after 4 and 29 days, respectively, which could be successfully treated by endovascular therapy. The complication rate was 21% (minor complication rate 4%, major complication rate 17%). The 30-day mortality rate was 21%. Conclusions: Implantation of stent-grafts in the hepatic artery is an effective emergency therapy and has a good technical success rate for patients with acute arterial hemorrhage.

  18. Biolimus-eluting stents with biodegradable polymer versus bare-metal stents in acute myocardial infarction

    DEFF Research Database (Denmark)

    Räber, Lorenz; Kelbæk, Henning; Taniwaki, Masanori

    2014-01-01

    BACKGROUND: This study sought to determine whether the 1-year differences in major adverse cardiac event between a stent eluting biolimus from a biodegradable polymer and bare-metal stents (BMSs) in the COMFORTABLE trial (Comparison of Biolimus Eluted From an Erodible Stent Coating With Bare Meta...... to improve cardiovascular events compared with BMS beyond 1 year. CLINICAL TRIAL REGISTRATION URL: http://www.clinicaltrials.gov. Unique identifier: NTC00962416....

  19. Microvascular Coronary Flow Comparison in Acute Myocardial Infarction Angioplasty treated with a mesh covered stent (MGUARD Stent) versus Bare Metal Stent

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    Lindefjeld, Dante S., E-mail: dslindef@puc.cl [Hospital Clínico, Pontificia Universidad Católica de Chile (Chile); Hospital Dr. Sótero del Río, Santiago-Chile (Chile); Guarda, Eduardo [Hospital Clínico, Pontificia Universidad Católica de Chile (Chile); Méndez, Manuel [Hospital Clínico, Pontificia Universidad Católica de Chile (Chile); Hospital Dr. Sótero del Río, Santiago-Chile (Chile); Martínez, Alejandro [Hospital Clínico, Pontificia Universidad Católica de Chile (Chile); Pérez, Osvaldo [Hospital Clínico, Pontificia Universidad Católica de Chile (Chile); Hospital Dr. Sótero del Río, Santiago-Chile (Chile); Fajuri, Alejandro; Marchant, Eugenio [Hospital Clínico, Pontificia Universidad Católica de Chile (Chile); Aninat, Mauricio; Torres, Humberto [Hospital Dr. Gustavo Fricke, Viña del Mar-Chile (Chile); Dussaillant, Gastón [Hospital Clínico Universidad de Chile, Santiago-Chile (Chile)

    2013-01-15

    Background: Distal embolization of thrombus/platelet aggregates decreases myocardial reperfusion during primary percutaneous coronary intervention (PCI), and is associated with worse immediate and long-term prognosis of patients with ST-elevation myocardial infarction (STEMI). Objective: Assess the efficacy of a mesh covered stent (MGuard™ stent, MGS) in preventing distal embolization and microvascular reperfusion impairment during primary PCI, compared with a bare metal stent (BMS). Methods: Forty patients with STEMI referred for primary PCI were randomized for stenting the culprit lesion with the MGS (n = 20) or a BMS (n = 20). Blinded experts performed off-line measurements of angiographic epicardial and microvascular reperfusion criteria: TIMI flow grade, myocardial blush, corrected TIMI frame count (cTFC). Results: At baseline clinical, angiographic and procedural variables were not different between groups. Post PCI TIMI flow grade was similar in both groups. We observed better myocardial Blush grade in group MGS compared to BMS (median value 3.0 vs 2.5, 2p = 0.006) and cTFC (mean cTFC: MGS 19.65 ± 4.07 vs BMS 27.35 ± 7.15, 2p < 0.001, cTFC mean difference MGS-BMS: 7.7, CI 95%: 3.94 to 11.46). MGS stent group had a higher percentage of successful angioplasty (cTFC ≤ 23: MGS 85% vs BMS 30%, 2p < 0.001). We had two cases of acute stent thrombosis (one for each group) at 30 days follow up, but no clinical events at 6 months follow up. Conclusions: In this exploratory study, MGS significantly improved microvascular reperfusion criteria compared with a BMS in primary PCI. However its safety and impact on clinical outcomes should be verified in larger randomized clinical trials.

  20. [Rescue treatment in acute thrombosis of intracranial stents].

    Science.gov (United States)

    Pumar, José M; Banguero, Alexandra; Arias-Rivas, Susana; Blanco, Miguel; Rodríguez-Yáñez, Manuel; Sucasas, Paula; Blanco, Miguel; Castiñeira-Mourenza, José A; Vázquez-Herrero, Fernando

    2014-02-01

    Introduccion. La trombosis aguda intrastent es una complicacion potencialmente grave en el stenting intracraneal. Es primordial determinar cual es la terapia mas adecuada en las trombosis intrastent. Caso clinico. Mujer de 58 años, el primer caso de trombosis aguda de un stent intracraneal, que fue tratada con exito mediante fibrinolisis tras la implantacion de un dispositivo diversificador de flujo (Silk) en un aneurisma basilar fusiforme. Conclusion. La administracion de abciximab como tratamiento de rescate parece segura en los casos de formaciones de trombos agudos intrastent.

  1. ”Missing clot” during mechanical thrombectomy in acute stroke using Solitaire stent retrieval system

    Directory of Open Access Journals (Sweden)

    Vikram Huded

    2016-01-01

    Full Text Available Stent retrieval system is an established treatment modality in acute ischemic stroke with large vessel occlusion. Here, we describe a complication which occurred during mechanical thrombectomy in three cases where the clot dislodged during retrieval. There was a possibility of the clot getting reinjected into the artery with possible dire consequences.

  2. Stent grafting of acute hepatic artery bleeding following pancreatic head resection

    Energy Technology Data Exchange (ETDEWEB)

    Stoupis, Christoforos [University of Berne, Inselspital, Department of Diagnostic, Interventional and Pediatric Radiology, Berne (Switzerland); Kreisspital, Radiology, Maennedorf (Switzerland); Ludwig, Karin; Triller, Juergen [University of Berne, Inselspital, Department of Diagnostic, Interventional and Pediatric Radiology, Berne (Switzerland); Inderbitzin, Daniel [University of Berne, Inselspital, Clinic for Visceral and Transplantation Surgery, Berne (Switzerland); Do, Dai-Do [University of Berne, Inselspital, Clinic for Angiology, Berne (Switzerland)

    2007-02-15

    The purpose of this study was to report the potential of hepatic artery stent grafting in cases of acute hemorrhage of the gastroduodenal artery stump following pancreatic head resection. Five consecutive male patients were treated because of acute, life-threatening massive bleeding. Instead of re-operation, emergency angiography, with the potential of endovascular treatment, was performed. Because of bleeding from the hepatic artery, a stent graft (with the over-the-wire or monorail technique) was implanted to control the hemmorhage by preserving patency of the artery. The outcome was evaluated. In all cases, the hepatic artery stent grafting was successfully performed, and the bleeding was immediately stopped. Clinically, immediately after the procedure, there was an obvious improvement in the general patient condition. There were no immediate procedure-related complications. Completion angiography (n=5) demonstrated control of the hemorrhage and patency of the hepatic artery and the stent graft. Although all patients recovered hemodynamically, three individuals died 2 to 10 days after the procedure. The remaining two patients survived, without the need for re-operation. Transluminal stent graft placement in the hepatic artery is a safe and technically feasible solution to control life-threatening bleeding of the gastroduodenal artery stump. (orig.)

  3. Acute and subacute stent thrombosis after primary percutaneous coronary intervention for ST-segment elevation myocardial infarction : incidence, predictors and clinical outcome

    NARCIS (Netherlands)

    Hesstermans, A. A. C. M.; van Werkum, J. W.; Zwart, B.; van der Heyden, J. A.; Kelder, J. C.; Breet, N. J.; van't Hof, A. W. J.; Koolen, J. J.; Brueren, B. R. G.; Zijlstra, F.; ten Berg, J. M.; Dambrink, Jan Hendrik Everwijn

    2010-01-01

    Background: Early coronary stent thrombosis occurs most frequent after primary percutaneous coronary intervention (PCI) for ST-segment elevation myocardial infarction (STEMI). Objectives: To identify the specific predictors of, respectively, acute and subacute stent thrombosis in patients after prim

  4. Outcomes after revascularisation with everolimus- and sirolimus-eluting stents in patients with acute coronary syndromes and stable angina pectoris

    DEFF Research Database (Denmark)

    Antonsen, Lisbeth; Thayssen, Per; Hansen, Henrik S

    2014-01-01

    Aims: The aim of this substudy of the SORT OUT IV trial was to compare clinical outcomes among patients with acute coronary syndromes (ACS) and stable angina pectoris (SAP) treated with everolimus-eluting stents (EES) or sirolimus-eluting stents (SES). Methods and results: We performed a post hoc...

  5. Predictive value of antiplatelet resistance on early stent thrombosis in patients with acute coronary syndrome

    Institute of Scientific and Technical Information of China (English)

    LI Lei; LI Hai-yan; QIAO Rui; YU Hai-yi; ZENG Hui; GAO Wei; ZHANG Jie

    2013-01-01

    Background Despite outstanding antiplatelet properties of aspirin and clopidogrel,some patients taking these drugs continue to suffer complications.Antiplatelet resistance appears to be a new prognostic factor in acute coronary syndrome patients for clinical events associated with stent thrombosis (ST).However,there is no optimal method to identify it and assess its correlation to clinical outcomes.This study sought to evaluate the predictive value of antiplatelet resistance assessed by whole blood impedance aggregometry for the risk of early ST in patients with acute coronary syndrome who underwent coronary stenting.Methods Platelet responses to aspirin and clopidogrel in 86 patients with acute coronary syndrome were measured by whole blood impedance aggregometry.Spontaneous platelet aggregation was defined as antiplatelet resistance identified by the increased electrical impedance.The clinical endpoint was early stent thrombosis during 30-day follow-up after coronary stenting.Results The prevalence of aspirin resistance,clopidogrel resistance and dual resistance of combined clopidogrel and aspirin resistance were 19.8%,12.8% and 5.8% respectively.Diabetes,female and higher platelet counts were more frequently detected in clopidogrel-resistant and dual-resistant patients.During 30-day follow-up,the patients with clopidogrel resistance and dual resistance had higher incidence of early stent thrombosis (18.2% vs.1.3%,40.0% vs.1.2%,P <0.05).Binary Logistic Regression analysis indicated that dual resistance remained an independent predicator for early stent thrombosis (odds ratio 34.064,95% CI 1.919-604.656,P=-0.016).Conclusions Antiplatelet resistance assessed by whole blood impedance aggregometry is paralleled to clinical events,and dual antiplatelet resistance is an independent predicator for early stent thrombosis in patients with acute coronary syndrome.As a physiological assessment of platelet reactivity,whole blood impedance aggregometry is a

  6. [Absorbable coronary stents. New promising technology].

    Science.gov (United States)

    Erbel, Raimund; Böse, Dirk; Haude, Michael; Kordish, Igor; Churzidze, Sofia; Malyar, Nasser; Konorza, Thomas; Sack, Stefan

    2007-06-01

    Coronary stent implantation started in Germany 20 years ago. In the beginning, the progress was very slow and accelerated 10 years later. Meanwhile, coronary stent implantation is a standard procedure in interventional cardiology. From the beginning of permanent stent implantation, research started to provide temporary stenting of coronary arteries, first with catheter-based systems, later with stent-alone technology. Stents were produced from polymers or metal. The first polymer stent implantation failed except the Igaki-Tamai stent in Japan. Newly developed absorbable polymer stents seem to be very promising, as intravascular ultrasound (IVUS) and optical coherence tomography have demonstrated. Temporary metal stents were developed based on iron and magnesium. Currently, the iron stent is tested in peripheral arteries. The absorbable magnesium stent (Biotronik, Berlin, Germany) was tested in peripheral arteries below the knee and meanwhile in the multicenter international PROGRESS-AMS (Clinical Performance and Angiographic Results of Coronary Stenting with Absorbable Metal Stents) study. The first magnesium stent implantation was performed on July 30, 2004 after extended experimental testing in Essen. The magnesium stent behaved like a bare-metal stent with low recoil of 5-7%. The stent struts were absorbed when tested with IVUS. Stent struts were not visible by fluoroscopy or computed tomography (CT) as well as magnetic resonance imaging (MRI). That means, that the magnesium stent is invisible and therefore CT and MRI can be used for imaging of interventions. Only using micro-CT the stent struts were visible. The absorption process could be demonstrated in a patient 18 days after implantation due to suspected acute coronary syndrome, which was excluded. IVUS showed a nice open lumen. Stent struts were no longer visible, but replaced by tissue indicating the previous stent location. Coronary angiography after 4 months showed an ischemia-driven target lesion

  7. Endovascular stent graft treatment of acute thoracic aortic transections due to blunt force trauma.

    LENUS (Irish Health Repository)

    Bjurlin, Marc A

    2012-02-01

    Endovascular stent graft treatment of acute thoracic aortic transections is an encouraging minimally invasive alternative to open surgical repair. Between 2006 and 2008, 16 patients with acute thoracic aortic transections underwent evaluation at our institution. Seven patients who were treated with an endovascular stent graft were reviewed. The mean Glasgow Coma Score was 13.0, probability of survival was .89, and median injury severity score was 32. The mean number of intensive care unit days was 7.7, mean number of ventilator support days was 5.4, and hospital length of stay was 10 days. Mean blood loss was 285 mL, and operative time was 143 minutes. Overall mortality was 14%. Procedure complications were a bleeding arteriotomy site and an endoleak. Endovascular treatment of traumatic thoracic aortic transections appears to demonstrate superior results with respect to mortality, blood loss, operative time, paraplegia, and procedure-related complications when compared with open surgical repair literature.

  8. Efficacy of recombinant tissue-type plasminogen activator thrombolysis and primary coronary stenting after acute myocardial infarction

    Institute of Scientific and Technical Information of China (English)

    陈步星; 王伟民; 赵红; 胡大一; 徐成斌; 赵明中; 卢明瑜; 刘健; 吴淳

    2003-01-01

    Objective To compare the efficacy of low dose recombinant tissue-type plasminogen activator (rt-PA) thrombolysis with primary coronary stenting after acute myocardial infarction.Methods Of 261 patients with first acute myocardial infarction, 131 were given low dose rt-PA intravenous thrombolysis, and 130 primary coronary stenting.Results The age, time from onset of chest pain to hospital presentation and infarct location between these two groups were comparable. The patency rate of the infarct-related artery (IRA) in patients in the thrombolysis group was significantly lower than that of patients in the primary stenting group (P0.05).Conclusion Comparing with low dose rt-PA thrombolytic therapy after acute myocardial infarction, primary coronary stenting has a higher patency rate of the IRA, better cardiac function and shorter hospitalization time.

  9. Thrombectomy assisted by carotid stenting in acute ischemic stroke management

    DEFF Research Database (Denmark)

    Steglich-Arnholm, Henrik; Holtmannspötter, Markus; Kondziella, Daniel;

    2015-01-01

    -term outcome (mRS ≤ 2). Harms included complications during and following EVT. Mean age was 64.3 years (standard deviation ±12.5), 40 (85%) patients received IVT initially. Median NIHSS was 16 (inter-quartile range 14-19). Mean time from stroke onset to recanalization was 311 min (standard deviation ±78......Extracranial carotid artery occlusion or high-grade stenosis with concomitant intracranial embolism causes severe ischemic stroke and shows poor response rates to intravenous thrombolysis (IVT). Endovascular therapy (EVT) utilizing thrombectomy assisted by carotid stenting was long considered risky......-center analysis of 47 consecutive stroke patients with carotid occlusion or high-grade stenosis and concomitant intracranial embolus treated between September 2011 and December 2014. Benefits included early improvement of stroke severity (NIHSS ≥ 10) or complete remission within 72 h and favorable long...

  10. Drug-eluting stents for acute coronary syndrome: a meta-analysis of randomized controlled trials.

    Directory of Open Access Journals (Sweden)

    Lishan Wang

    Full Text Available Drug-eluting stents (DES are increasingly used for treatment of acute coronary syndrome (ACS. However, clinical efficacy and safety of various types of DES is not well established in these subjects. We therefore evaluated clinical utility of second-generation and first-generation DES in patients with ACS by conducting a meta-analysis.A search of Medline, Embase, the Cochrane databases, and Web of Science was made. Randomized controlled trials (RCTs which compared second-generation DES (everolimus-eluting stents [EES] or zotarolimus-eluting stents [ZES] versus first-generation DES (sirolimus-eluting stents [SES] or paclitaxe-eluting stents [PES] in patients with ACS and provided data on clinical efficacy or safety endpoints were included. Pooled estimates were calculated using random-effects model.A total of 2,757 participants with ACS in 6 RCTs were included. Compared with first-generation one, second-generation DES trended to be associated with the decreased incidence of definite or probable stent thrombosis in ACS patients (risk ratio [RR]  = 0.60, 95% confidence intervals [CI] 0.33 to 1.07, p = 0.09. However, the rate of target lesion revascularization (TLR significantly increased in second-generation DES (RR = 2.08, 95%CI 1.25 to 3.47, p = 0.005. There were no significant differences in the incidence of major adverse cardiac events (MACEs, all-cause death, cardiac death, and recurrent myocardial infarction between the two arms (all p>0.10. The second-generation EES showed a tendency towards lower risk of MACEs (p = 0.06 and a beneficial effect on reducing stent thrombosis episodes (p = 0.009, while the second-generation ZES presented an increased occurrence of MACEs (p = 0.02 and TLR (p = 0.003.Second-generation DES, especially EES, appeared to present a lower risk of stent thrombosis, whereas second-generation ZES might increase the need for repeat revascularization in ACS patients. During coronary

  11. The History of Primary Angioplasty and Stenting for Acute Myocardial Infarction.

    Science.gov (United States)

    Smilowitz, Nathaniel R; Feit, Frederick

    2016-01-01

    The evolution of the management of acute myocardial infarction (MI) has been one of the crowning achievements of modern medicine. At the turn of the twentieth century, MI was an often-fatal condition. Prolonged bed rest served as the principal treatment modality. Over the past century, insights into the pathophysiology of MI revolutionized approaches to management, with the sequential use of surgical coronary artery revascularization, thrombolytic therapy, and percutaneous coronary intervention (PCI) with primary coronary angioplasty, and placement of intracoronary stents. The benefits of prompt revascularization inspired systems of care to provide rapid access to PCI. This review provides a historical context for our current approach to primary PCI for acute MI.

  12. Disseminated Intravascular Coagulation as a Possible Cause of Acute Coronary Stent Thrombosis: A Case Report and Literature Review

    Directory of Open Access Journals (Sweden)

    Syed Amer

    2012-01-01

    Full Text Available Disseminated intravascular coagulation (DIC, as a cause of acute coronary stent thrombosis, has not yet been reported to our knowledge. We report a case of 64-year-old male, who presented with non-ST-segment elevation myocardial infarction (NSTEMI. Coronary angiography revealed right coronary artery (RCA stenosis and a drug eluting stent was deployed. Fifteen hours following the intervention, the patient developed an inferior wall ST elevation myocardial infarction. Repeat cardiac catheterization showed an acute in-stent thrombosis. Following thrombectomy, another stent was placed. The patient noted to have an acute drop in platelet count following the second intervention. Two hours following repeat intervention, the patient again developed chest pain and EKG showed recurrent ST-segment elevations in leads II, III, and aVF. Prior to repeat cardiac catheterization, the patient became unresponsive and developed cardiogenic shock. The patient was resuscitated and intubated, and repeat catheterization showed complete stent thrombosis. Intracoronary tissue plasminogen activator (tPA was given. The platelet count further dropped. Additional studies confirmed the diagnosis of DIC. No further cardiac catheterization was done at this point. The patient then later had a cardiac arrest and unfortunately cardiopulmonary resuscitation could not revive him. Amongst the etiologies of acute stent thrombosis, DIC was deemed a possible cause.

  13. Coronary Stents: The Impact of Technological Advances on Clinical Outcomes.

    Science.gov (United States)

    Mennuni, Marco G; Pagnotta, Paolo A; Stefanini, Giulio G

    2016-02-01

    Percutaneous coronary interventions (PCI) were proposed in the late 1970s as an alternative to surgical coronary artery bypass grafting for the treatment of coronary artery disease. Important technological progress has been made since. Balloon angioplasty was replaced by bare metal stents, which allowed to permanently scaffold the coronary vessel avoiding acute recoil and abrupt occlusion. Thereafter, the introduction of early generation drug-eluting stents (DES) has significantly improved clinical outcomes, primarily by markedly reducing the risk of restenosis. New generation DES with thinner stent struts, novel durable or biodegradable polymer coatings, and new limus antiproliferative agents, have further improved upon the safety and efficacy profile of early generation DES. The present article aims to review the impact of technological advances on clinical outcomes in the field of PCI with coronary stents, and to provide a brief overview on clinical margins of improvement and unmet needs of available DES.

  14. Clinical safety of cardiac magnetic resonance imaging at 3 T early after stent placement for acute myocardial infarction

    Energy Technology Data Exchange (ETDEWEB)

    Jehl, Jerome; Comte, Alexandre; Aubry, Sebastien; Kastler, Bruno [Hopital Jean Minjoz, Service de Radiologie A and C, Centre Hospitalier Universitaire de Besancon, Besancon (France); Meneveau, Nicolas; Schiele, Francois [Hopital Jean Minjoz, Service de Cardiologie, Centre Hospitalier Universitaire de Besancon, Besancon (France)

    2009-12-15

    The purpose of this study was to prospectively evaluate the safety of cardiac magnetic resonance (CMR) imaging at 3 T performed early (less than 14 days) after bare metal or drug-eluting coronary stent implantation in patients with acute myocardial infarction (AMI). Seventy-two consecutive patients with AMI treated by percutaneous revascularisation with a stent underwent CMR examination with a median delay of 6 days. Patients were followed-up for major adverse cardiac events, during hospitalisation and at 6 months. After CMR imaging, no acute stent thrombosis, death or repeated AMI were recorded at 6-month follow-up. Two symptomatic in-stent restenoses and two silent in-stent restenoses were recorded, at a mean delay of 106 days. In our population, we found a target revascularisation rate of 5.6%. This is consistent with the 6-month event rates after coronary artery stent (CAS) placement for AMI, evaluated by several studies. This preliminary clinical study supports the safety of 3-T CMR imaging performed early after coronary stent placement. (orig.)

  15. EFFICACY AND SAFETY OF GLYCOPROTEIN IIB/IIIA BLOCKER MONOFRAM IN CORONARY STENTING IN PATIENTS WITH ACUTE MYOCARDIAL INFARCTION

    Directory of Open Access Journals (Sweden)

    E. I. Makhiyanova

    2011-01-01

    Full Text Available  Aim. To study of efficacy and safety of glycoprotein IIb/IIIa blocker monafram in acute ST-segment elevation myocardial infarction (STEMI patients, underwent coronary stenting. Material and methods. 220 STEMI patients were included in the trial; they were split into two groups. 109 patients of the first group were underwent coronary stenting with i/v monafram therapy. Coronary stenting without monafram therapy was performed in 111 patients of the second group. Bare metal stents were used in all patients. Deaths, stent thrombosis, individual intolerance, allergic reactions, bleeding were registered during hospitalization. Results. There were 3 (2.75% cases of stent thrombosis in monafram group and 4 (3.6% ones - in the control group. Good tolerance of monafram was observed in all patients. There were no allergic reactions, major and minor bleedings. Reinfarction rate was similar in both groups during 30 days observational period. Conclusions. Monafram therapy is effective and safe in acute STEMI patients underwent coronary stenting.  

  16. Fully biodegradable coronary stents : progress to date.

    Science.gov (United States)

    Ramcharitar, Steve; Serruys, Patrick W

    2008-01-01

    The limitations of currently available metallic drug-eluting stents have renewed interest in biodegradable stents (BDS). Apart from removing the (offending) foreign material that may potentiate a thrombotic event, BDS have the advantage of avoiding 'full metal jackets,' and thus can preclude subsequent coronary surgery. In addition, they do not interfere with the diagnostic evaluation of non-invasive imaging such as cardiac magnetic resonance and CT. There are now several BDS in development or in clinical trials that incorporate a variety of biodegradable polymer technologies. Two broad categories of materials are generally used: those made from organic biopolymers and those made from corrodible metals. However, to date, none of the materials/stents tested have been able to establish a perfect balance between biocompatibility, the kinetics of degradation needed to maintain mechanical strength to limit recoil, and inflammation. However, studies, such as the ABSORB trial with the everolimus eluting poly-L-lactide stent, which demonstrated comparable restenotic rates with bare metallic stents and a low incidence of major adverse cardiac events (MACE) at 12 months of 3.3%, with only one patient having a non-Q-wave myocardial infarction and no target lesion revascularization, suggest that there has been significant progress with respect to the earlier prototypes. The acute recoil observed could potentially be addressed with the polytyrosine REVA stent currently being evaluated in the RESORB trial, which incorporates a novel locking mechanism within its design. Alternative BDS designs include the combination of an antiproliferative drug with endothelial progenitor cell capturing antibodies to facilitate epithelialization and/or dual eluting having, in addition to the antiproliferative drug, polymeric salicyclic acid to limit inflammation. Compared with biodegradable polymers, there are fewer metals used in the manufacture of BDS. The only metal BDS in trials is the

  17. Role of Self-Expandable Metal Stents in Acute Variceal Bleeding

    Directory of Open Access Journals (Sweden)

    Fuad Maufa

    2012-01-01

    Full Text Available Acute variceal bleeding continues to be associated with significant mortality. Current standard of care combines hemodynamic stabilization, antibiotic prophylaxis, pharmacological agents, and endoscopic treatment. Rescue therapies using balloon tamponade or transjugular intrahepatic portosystemic shunt are implemented when first-line therapy fails. Rescue therapies have many limitations and are contraindicated in some cases. Placement of fully covered self-expandable metallic stent is a promising therapeutic technique that can be used to control bleeding in cases of refractory esophageal bleeding as an alternative to balloon tamponade. These stents can be left in place for as long as two weeks, allowing for improvement in liver function and institution of a more definitive treatment.

  18. Reduction of stent thrombosis in patients with acute coronary syndromes treated with rivaroxaban in ATLAS-ACS 2 TIMI 51

    NARCIS (Netherlands)

    Gibson, C.M.; Chakrabarti, A.K.; Mega, J.; Bode, C.; Bassand, J.P.; Verheugt, F.W.A.; Bhatt, D.L.; Goto, S.; Cohen, M.; Mohanavelu, S.; Burton, P.; Stone, G.; Braunwald, E.

    2013-01-01

    OBJECTIVES: The aim of this study was to determine if rivaroxaban is associated with a reduction in stent thrombosis among patients with acute coronary syndromes (ACS) in the ATLAS-ACS 2 TIMI 51 (Anti-Xa Therapy to Lower Cardiovascular Events in Addition to Standard Therapy in Subjects With Acute Co

  19. Colonic stenting as bridge to surgery versus emergency surgery for management of acute left-sided malignant colonic obstruction: a multicenter randomized trial (Stent-in 2 study

    Directory of Open Access Journals (Sweden)

    Scholten Pieter

    2007-07-01

    Full Text Available Abstract Background Acute left-sided colonic obstruction is most often caused by malignancy and the surgical treatment is associated with a high mortality and morbidity rate. Moreover, these operated patients end up with a temporary or permanent stoma. Initial insertion of an enteral stent to decompress the obstructed colon, allowing for surgery to be performed electively, is gaining popularity. In uncontrolled studies stent placement before elective surgery has been suggested to decrease mortality, morbidity and number of colostomies. However stent perforation can lead to peritoneal tumor spill, changing a potentially curable disease in an incurable one. Therefore it is of paramount importance to compare the outcomes of colonic stenting followed by elective surgery with emergency surgery for the management of acute left-sided malignant colonic obstruction in a randomized multicenter fashion. Methods/design Patients with acute left-sided malignant colonic obstruction eligible for this study will be randomized to either emergency surgery (current standard treatment or colonic stenting as bridge to elective surgery. Outcome measurements are effectiveness and costs of both strategies. Effectiveness will be evaluated in terms of quality of life, morbidity and mortality. Quality of life will be measured with standardized questionnaires (EORTC QLQ-C30, EORTC QLQ-CR38, EQ-5D and EQ-VAS. Morbidity is defined as every event leading to hospital admission or prolonging hospital stay. Mortality will be analyzed as total mortality as well as procedure-related mortality. The total costs of treatment will be evaluated by counting volumes and calculating unit prices. Including 120 patients on a 1:1 basis will have 80% power to detect an effect size of 0.5 on the EORTC QLQ-C30 global health scale, using a two group t-test with a 0.05 two-sided significance level. Differences in quality of life and morbidity will be analyzed using mixed-models repeated measures

  20. The Impact of the Acute Results on the Long - Term Outcome after the Treatment of In- stent Restenosis: A Serial Intravascular Ultrasound Study

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    @@ Stenting reduces acute complications and restenosis compared to balloon angioplasty and other devices. However, in- stent restenosis (ISR) is an important clinical problem. The current serial intravascular ultrasound (IVUS)analysis was undertaken to determine whether the acute results obtained during the treatment of ISR influence the long term results and whether this is true for patients treated with and without adjunct brachytherapy.

  1. Acute stenting and thromboaspiration in basilar artery occlusions due to embolism from the dominating vertebral artery

    Energy Technology Data Exchange (ETDEWEB)

    Nedeltchev, K.; Remonda, L.; Brekenfeld, C.; Ozdoba, C.; Schroth, G. [Institute of Diagnostic and Interventional Neuroradiology, University of Bern, Inselspital, Freiburgstrasse 4, 3010, Bern (Switzerland); Do, D.D. [Institute of Angiology, University of Bern, Inselspital, Bern (Switzerland); Arnold, M.; Mattle, H.P. [Department of Neurology, University of Bern, Inselspital, Bern (Switzerland)

    2004-08-01

    Intra-arterial thrombolysis (IAT) is the only treatment that has demonstrated benefit in patients with acute basilar artery occlusions (ABAO). IAT may be difficult to perform when access to the occluded basilar artery (BA) is prevented by pathology of the vertebral arteries (VA). We report on two patients with ABAO due to embolism from the dominating VA. Catheter navigation through the occluded VA and thromboaspiration enabled access to the BA. Thromboaspiration alone or in addition to IAT resulted in a complete recanalization of the BA and a favorable clinical outcome. A stent was deployed at the site of the stenosis in the VA either prior to or immediately after BA recanalization. (orig.)

  2. Vascular Response to Experimental Stent Malapposition and Under-Expansion.

    Science.gov (United States)

    O'Brien, Caroline C; Lopes, Augusto C; Kolandaivelu, Kumaran; Kunio, Mie; Brown, Jonathan; Kolachalama, Vijaya B; Conway, Claire; Bailey, Lynn; Markham, Peter; Costa, Marco; Ware, James; Edelman, Elazer R

    2016-07-01

    Up to 80% of all endovascular stents have malapposed struts, and while some impose catastrophic events others are inconsequential. Thirteen stents were implanted in coronary arteries of seven healthy Yorkshire pigs, using specially-designed cuffed balloons inducing controlled stent malapposition and under-expansion. Optical coherence tomography (OCT) imaging confirmed that 25% of struts were malapposed (strut-wall distance strut thickness) to variable extent (max. strut-wall distance malapposed group 0.51 ± 0.05 mm vs. apposed group 0.09 ± 0.05 mm, p = 2e-3). Imaging at follow-up revealed malapposition acutely resolved (struts remained malapposed at day 5), with strong correlation between lumen and the stent cross-sectional areas (slope = 0.86, p < 0.0001, R (2) = 0.94). OCT in three of the most significantly malapposed vessels at baseline showed high correlation of elastic lamina area and lumen area (R (2) = 0.96) suggesting all lumen loss was related to contraction of elastic lamina with negligible plaque/intimal hyperplasia growth. Simulation showed this vascular recoil could be partially explained by the non-uniform strain environment created from sub-optimal expansion of device and balloon, and the inability of stent support in the malapposed region to resist recoil. Malapposition as a result of stent under-expansion is resolved acutely in healthy normal arteries, suggesting existing animal models are limited in replicating clinically observed persistent stent malapposition.

  3. Persistent high levels of plasma oxidized low-density lipoprotein after acute myocardial infarction predict stent restenosis

    NARCIS (Netherlands)

    T. Naruko; M. Ueda; S. Ehara; A. Itoh; K. Haze; N. Shirai; Y. Ikura; M. Ohsawa; H. Itabe; Y. Kobayashi; H. Yamagishi; M. Yoshiyama; J. Yoshikawa; A.E. Becker

    2006-01-01

    Objective-Recently, elevated levels of plasma oxidized low-density lipoprotein (LDL) have been shown to relate to plaque instability in human atherosclerotic lesions. We investigated prospectively patients admitted with acute myocardial infarction (AMI) who underwent primary coronary stenting to eva

  4. Multiobjective design optimisation of coronary stents.

    Science.gov (United States)

    Pant, Sanjay; Limbert, Georges; Curzen, Nick P; Bressloff, Neil W

    2011-11-01

    We present here a multi-objective and multi-disciplinary coronary stent design optimization paradigm. Coronary stents are tubular, often mesh-like, structures which are deployed in diseased (stenosed) artery segments to provide a scaffolding feature that compresses atheromatus plaque, hence restoring luminal area and maintaining vessel patency. A three variable geometry parameterisation of a CYPHER (Cordis Corporation, Johnson & Johnson co.) type stent is proposed to explore the functionality of a sequence of circumferential rings connected by 'n' shaped links. The performance of each design is measured by six figures of merit (objectives/metrics) representing (i) acute recoil, (ii) tissue stresses, (iii) haemodynamic disturbance, (iv) drug delivery, (v) uniformity of drug distribution, and (vi) flexibility. These metrics are obtained from computational simulations of (i) structural deformation through balloon inflated expansion of a stent into contact with a stenosed vessel, (ii) pulsatile flow over the deformed stent embedded in the vessel wall, (iii) steady-state drug distribution into the tissue, and (iv) flexibility of a stent in response to an applied moment. Design improvement is obtained by a multi-objective surrogate modelling approach using a non-dominated sorting genetic algorithm (NSGA-II) to search for an optimal family of designs. A number of trade-offs between the different objectives are identified. In particular a conflict between pairs of the following objectives are shown -- (a) volume average stress vs. recoil, (b) volume average drug vs. volume average stress, (c) flexibility vs. volume average stress, (d) flexibility vs. haemodynamic disturbance, (e) volume average drug vs. haemodynamic disturbance, and (f) uniformity of drug vs. volume average stress. Different paradigms to choose the optimal designs from the obtained Pareto fronts are presented and under each such paradigm, the optimal designs and there relative positions with respect to a

  5. Endovascular therapy of acute tumour-related obstruction of the superior vena cava using a self-expanding Nitinol stent

    Directory of Open Access Journals (Sweden)

    Peter Kamusella

    2013-11-01

    Full Text Available Objective: To evaluate, in a retrospective study, the clinical efficacy and safety of the self-expanding Nitinol stent in the superior vena cava to alleviate upper venous congestion.Method: In 22 patients (15 men, 7 women, a tumour-related compression of the superior vena cava was diagnosed by spiral CT after intravenous application of contrast medium. Clinically, acute superior vena cava syndrome was found in all patients. Histologically, a bronchial carcinoma was present in 14/22, a lymphoma in 6/22, and mediastinal lymphnode metastases (1 breast carcinoma, 1 malignant melanoma in 2/22. After a transfemoral approach, cavography was initially performed. The degree of stenosis was classified according to the Stanford classification. In accordance with the degree of stenosis, a self-expanding Nitinol stent was placed.Results: Endovascular stent implantation was conducted without complications in all patients. A marked improvement in acute symptoms was observed clinically within 24 hours in all patients. In the follow-up period of up to 2 years, there were no cases of stent migration. In 7/22 patients, the CT follow-ups revealed tumour progression (3/7 after 3 months, 2/7 after 6 months, and 2/7 after 12 months with evidence of residual stenosis caused by tumour growth through the stent mesh. During the follow-up period, 15/22 patients died (mean survival 6.4 months.Conclusion: Self-expanding Nitinol stents provide endovascular therapy for superior vena cava syndrome, having a high radial expansive force and the facility to be placed precisely, and alleviating acute, life-threatening symptoms in the palliative situation.

  6. Drug-eluting stents and acute myocardial infarction:A lethal combination or friends?

    Institute of Scientific and Technical Information of China (English)

    Shuji; Otsuki; Manel; Sabaté

    2014-01-01

    Primary percutaneous coronary intervention is the preferred reperfusion strategy for patients presenting with ST-segment elevation myocardial infarction(STEMI). First generation drug-eluting stents(DES),(sirolimus drug-eluting stents and paclitaxel drug-eluting stents), reduce the risk of restenosis and target vessel revascularization compared to bare metal stents. However, stent thrombosis emerged as a major safety concern with first generation DES. In response to these safety issues, second generation DES were developed with different drugs, improved stent platforms and more biocompatible durable or bioabsorbable polymeric coating. This article presents an overview of safety and efficacy of the first and second generation DES in STEMI.

  7. 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).

  8. Patency of paclitaxel-eluting versus bare metal stents long term after implantation in acute ST-segment elevation myocardial infarction.

    Science.gov (United States)

    Vink, Maarten A; Van Nooijen, Ferdinand C; Laarman, Gerrit J; Suttorp, Maarten J; Tijssen, Jan G; Slagboom, Ton; Patterson, Mark S; Van Der Schaaf, Rene J; Kiemeneij, Ferdinand; Amoroso, Giovanni; Dirksen, Maurits T

    2011-11-01

    Drug-eluting stents effectively inhibit neointimal hyperplasia within the first year, thereby reducing the need for repeat revascularization. However, a delayed pattern of restenosis might be more prominent in drug-eluting stents compared to bare metal stents (BMSs). The extent of restenosis of paclitaxel-eluting stents (PESs) long term after implantation in acute ST-segment elevation myocardial infarction is currently unknown. The present study was designed to evaluate very late luminal loss (VLLL) of PESs used in ST-segment elevation myocardial infarction compared to BMSs. A total of 116 patients (61 with PESs and 55 with BMSs) initially included in the Paclitaxel Eluting Stent Versus Conventional Stent in ST-segment Elevation Myocardial Infarction (PASSION) trial and who were free from previous lesion failure underwent angiographic follow-up. Off-line quantitative coronary analysis of the angiogram immediately after stent implantation and at follow-up was performed. The primary end point was VLLL within the stent. The presence of binary restenosis was defined as diameter stenosis >50% as a secondary end point. The mean interval between stent implantation and follow-up was 4.1 ± 0.5 years in both stent groups. In-stent VLLL was 0.12 mm (interquartile range -0.03 to 0.42) in the PES group versus 0.30 mm (interquartile range 0.08 to 0.69) in the BMS group (p = 0.011). In-segment binary restenosis was found in 4 patients (6.6%) with a PES and 6 patients (10.9%) with a BMS (p = 0.40). In conclusion, angiographic follow-up 4 years after implantation in ST-segment elevation myocardial infarction showed that in patients prospectively randomized to PESs or BMSs, VLLL was low in both stent groups. PESs were associated with lower VLLL than BMSs, and the observed rate of binary restenosis was not significantly different between the 2 stent groups.

  9. Clinical application of self-expanding metallic stent in the management of acute left-sided colorectal malignant obstruction

    Institute of Scientific and Technical Information of China (English)

    You-Ben Fan; Ying-Sheng Cheng; Ni-Wei Chen; Hui-Min Xu; Zhe Yang; Yue Wang; Yu-Yao Huang; Qi Zheng

    2006-01-01

    AIM: To summarize our experience with the application of self-expanding metallic stent (SEMS) in the management of acute left-sided colorectal malignant obstruction.METHODS: A retrospective chart review of all patients undergoing placement of SEMS between April 2000 and January 2004 was performed.RESULTS: Insertion of SEMS was attempted in 26patients under fluoroscopic guidance with occasional endoscopic assistance. The sites of lesions were located in splenic flexure of two patients, left colon of seven patients, sigmoid colon of eight patients and rectum of nine patients. The intended uses of SEMS were for palliation in 7 patients and as a bridge to elective surgery in 19 patients. In the latter group, placement of SEMS allowed for preoperative systemic and bowel preparation and the following one-stage anastomosis. Successful stent placement was achieved in 22 (85%) of the 26patients. The clinical bowel obstruction resolved 24 hours after successful stent placement in 21 (95%) patients.Three SEMS-related minor complications occurred, two stents migrated and one caused anal pain.CONCLUSION: SEMS represents an effective and safe tool in the management of acute malignant colorectal obstruction. As a bridge to surgery, SEMS can provide time for systematic support and bowel preparation and obviate the need for fecal diversion or on-table lavage.As a palliative measure, SEMS can eliminate the need for emergent colostomy.

  10. 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

    Directory of Open Access Journals (Sweden)

    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.

  11. Endothelial cell recovery, acute thrombogenicity, and monocyte adhesion and activation on fluorinated copolymer and phosphorylcholine polymer stent coatings.

    Science.gov (United States)

    Chin-Quee, Shawn L; Hsu, Steve H; Nguyen-Ehrenreich, Kim L; Tai, Julie T; Abraham, George M; Pacetti, Stephen D; Chan, Yen F; Nakazawa, Gaku; Kolodgie, Frank D; Virmani, Renu; Ding, Nadine N; Coleman, Leslie A

    2010-02-01

    This study compares the effects of two polymers currently being marketed on commercially available drug-eluting stents, PVDF-HFP fluorinated copolymer (FP) and phosphorylcholine polymer (PC), on re-endothelialization, acute thrombogenicity, and monocyte adhesion and activity. Rabbit iliac arteries were implanted with cobalt-chromium stents coated with FP or PC polymer (without drug) and assessed for endothelialization at 14 days by confocal and scanning electron microscopy (SEM). Endothelialization was equivalent and near complete for FP and PC polymer-coated stents (>80% by SEM). Acute thrombogenicity was assessed in a Chandler loop model using porcine blood. Thrombus adherence was similar for both polymers as assessed by clot weight, thrombin-antithrombin III complex, and lactate dehydrogenase expression. In vitro cell adhesion assays were performed on FP and PC polymer-coated glass coupon surfaces using HUVECs, HCAECs, and THP-1 monocytes. The number of ECs adhered to FP and control surfaces were equivalent and significantly greater than on PC surfaces (p<0.05). There were no differences in THP-1 monocyte adhesion and cytokine (MCP-1, RANTES, IL-6, MIP-1alpha, MIP-1beta, G-CSF) expression. The data suggests that biological responses to both FP and PC polymer are similar, with no mechanistic indication that these polymers would be causative factors for delayed vessel healing in an acute timeframe.

  12. Long-term outcome of patients of over 85 years old with acute coronary syndrome undergoing percutaneous coronary stenting: a comparison of bare metal stent and drug eluting stent

    Institute of Scientific and Technical Information of China (English)

    MA Han-ying; ZHOU Yu-jie; Ronald J Dick; SHI Dong-mei; LIU Yu-yang; CHENG Wan-jun; GUO Yong-he; WANG Jian-long; GE Hai-long

    2008-01-01

    Background Patients aged over 85 years have been under-represented in percutaneous coronary intervention (PCI)trials despite an increase in referrals for PCI. The long-term safety and efficacy of percutaneous coronary stenting in patients aged over 85 years with acute coronary syndrome (ACS) remain unclear. Moreover it is unknown whether there are differences between bare metal stent (BMS) and drug eluting stent (DES) in this special population.Methods A total of 80 patients with ACS aged over 85 years undergoing stenting (BMS group n=21 vs DES group n=59)were retrospectively studied. In-hospital, one year and overall clinical follow-up (12-36 months) of major adverse cardiac events (MACEs) including cardiac deaths, myocardial infarction, target lesion revascularization (TLR) and target vessel revascularization (TVR) as well as stroke and other major bleeding were compared between the two groups.Results In the entire cohort, the procedure success rate was 93.8% with TIMI-3 coronary flow post-PCI in 93.8% of the vessels and the procedure related complication was 17.5%. The incidence of in-hospital MACEs in BMS group was higher (14.3% vs 6.8%, P=0.30). The 1-year incidence of MACEs in DES group was 7.0% while there was no MACE in the BMS group. Clinical follow-up for 12-36 months showed that the overall survival free from MACE was 82.9% and the incidence of MACE in the BMS group was lower (5.3% vs 21.1%, P=0.20). Multivariate regression analysis showed that the creatinine level (OR:1.013; 95%C1: 1.006-1.020; P=0.004) and hypertension (OR:3.201; 95%C1: 1.000-10.663;P=0.04) are two major factors affecting the long-term MACE.Conclusions Percutaneous coronary stenting in patients aged over 85 years is safe and provides good short and long-term efficacy. Patients with renal dysfunction and hypertension may have a relatively high incidence of MACE.

  13. Effect of biolimus-eluting stents with biodegradable polymer vs bare-metal stents on cardiovascular events among patients with acute myocardial infarction

    DEFF Research Database (Denmark)

    Räber, Lorenz; Kelbæk, Henning; Ostojic, Miodrag

    2012-01-01

    The efficacy and safety of drug-eluting stents compared with bare-metal stents remains controversial in patients with ST-segment elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (PCI)....

  14. Mechanical Thrombectomy using a solitaire stent in acute ischemic stroke; The relationship between the visible antegrade flow on first device deployment and final success in revascularization

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Sung Ho; Lee, Byung Hon; Hwang, Yoon Joon; Kim, Su Young; Lee, Ji Young; Hong, Keun Sik; Cho, Yong Jin [Ilsan Paik Hospital, Inje University College of Medicine, Goyang (Korea, Republic of)

    2015-05-15

    The purpose of the study was to evaluate the relationship between the successful revascularization on the first Solitaire stent deployment and the successful revascularization on the final angiography in acute ischemic stroke. From February 2012 to April 2014, 24 patients who underwent Solitaire stent thrombectomy as the first thrombectomy method for treatment of acute ischemic strokes were retrospectively reviewed. When the first Solitaire stent was deployed, 9 patients showed revascularization (Group 1) and 15 patients did not show revascularization (Group 2). Revascularization immediately after the first Solitaire stent removal and on the final angiography were comparatively assessed between the 2 groups. Statistical analysis was performed by the Fisher exact test and Student's t-test. The rates of revascularization maintenance immediately after the first Solitaire stent removal were 89% in Group 1 and 27% in Group 2, respectively (p = 0.009), and the rates of final successful revascularization were 100% in Group 1 and 47% in Group 2, respectively (p = 0.009). There was a statistically significant difference between the 2 groups. Revascularization on the first Solitaire stent deployment can be a useful predictor in evaluating the success of final revascularization in the treatment of acute ischemic stroke.

  15. Application of a new-type sutureless anastomosis stent to the primary reconstruction of the bilioenteric continuity after acute bile duct injury in dogs

    Institute of Scientific and Technical Information of China (English)

    Jianhui Li; Yi Lü; Bo Qu; Zhiyong Zhang; Chang Liu; Yuan Shi; Bo Wang; Xuewen Ji; Liang Yu

    2007-01-01

    Objective: To evaluate the effect of a new-type sutureless magnetic bilioenteric anastomosis stent that was used to reconstruct the bilioenteric continuity (primarily under the circumstances of severe inflammation after acute bile duct injury in dogs).Methods: Establishing an animal model of acute bile duct injury with severe inflammation and bile peritonitis in dogs. The newtype sutureless magnetic bilioenteric anastomosis stent was used to reconstruct the bilioenteric continuity primarily. Results: The experiment group anastomosis healed well with a mild local inflammation reaction, and the collagen lined up in order without the occurrence of observable bile leakage and infection. Conclusion: It was safe and feasible to use the new-type anastomosis stent to reconstruct the bilioenteric continuity primarily under the circumstances of severe inflammation after acute bile duct injury in dogs.

  16. Coronary stenting with cardiogenic shock due to acute ascending aortic dissection

    Institute of Scientific and Technical Information of China (English)

    Yuichi; Hanaki; Kazuhiko; Yumoto; Seigen; I; Hajime; Aoki; Tomoyuki; Fukuzawa; Takahiro; Watanabe; Kenichi; Kato

    2015-01-01

    A 65-year-old man developed chest pain under cardiogenic shock. Coronary angiography revealed severe stenosis from the ostium of the left main coronary artery(LMCA) to the left anterior descending artery(LAD). Intravascular ultrasound(IVUS) identified a large hematoma that originated from the aorta and extended into the LAD, thereby compressing the true lumen. Type A aortic dissection(TAAD) that involved the LMCA was diagnosed by IVUS. Coronary stenting was performed via the LMCA to the proximal LAD, which resulted in coronary blood flow restoration and no further propagation of dissection. Elective surgical aortic repair was performed 2 wk after the stenting. LMCA stenting under IVUS guidance is effective for prompt diagnosis and precise stent deployment in patients with cardiogenic shock due to TAAD with LMCA dissection.

  17. Successful treatment of cardiogenic shock by stenting of the left main coronary artery in acute myocardial infarction

    Directory of Open Access Journals (Sweden)

    Knežević Božidarka

    2008-01-01

    Full Text Available Introduction. Patients with non-ST elevation acute coronary syndromes (NSTE-ACS are sometimes severely hemodynamicly compromised. Urgent coronary angiography should be performed in these patients in percutaneous coronary intervention (PCI centers according to the ESC NSTE-ACS guidelines to determine suitabilty for percutaneous or surgical revascularization. Case report. We reported a 62-year-old male with chest pain admitted to the Coronary Care Unit. ST segment depression of 2 mm in leads I, L and V4-6 was revealed at electrocardiogram. After following 6 hours the patient had chest pain and signs of cardiogenic shock despite of the therapy. Chest x-ray showed pulmonary edema. Echocardiographic examination showed dyskinetic medium and apical segments of septum. The patient underwent coronary angiography immediately which revealed 75% stenosis of the left main coronary artery with thrombus. The use of a GPIIb/III inhibitor-tirofiban and stent implantation resulted in TIMI III flow. After that the patient had no chest pain and acute heart failure subsided in the following days Echocardiography done at the fourth day from PCI showed only hypokinesis medium and apical segment of septum. The patient was discharged at day 11 from admission in a stable condition. Conclusion. Stenting of left main coronary artery stenosis in patients with cardiogenic shock and non- ST segment elevation acute coronary syndromes may be a life saving procedure.

  18. Gender difference in patients with acute myocardial infarction treated by primary percutaneous coronary intervention in drug-eluting stent era

    Institute of Scientific and Technical Information of China (English)

    GE Jun-bo

    2010-01-01

    @@ Primary percutaneous coronary intervention (PCI) has been the standard of care for patients with acuteST-elevation myocardial infarction (STEMI) within 12 hours of symptom onset in modern era.~(1,2) The advances and applications of robust anti-platelet and anti-coagulation medicines further improve the outcome of STEMI patients undergoing primary PCI,~3 and drug-eluting stent (DES) has also been proven to be effective and safe when applying in primary PCI.~4 Historical data indicated that women undergoing PCI exerted worse outcomes than male patients, and the gender differences in outcome after PCI are still topical and of interest, especially the outcome after primary PCI.

  19. Long-term outcomes of palliative colonic stenting versus emergency surgery for acute proximal malignant colonic obstruction: a multicenter trial

    Science.gov (United States)

    Siddiqui, Ali; Cosgrove, Natalie; Yan, Linda H.; Brandt, Daniel; Janowski, Raymond; Kalra, Ankush; Zhan, Tingting; Baron, Todd H.; Repici, Allesandro; Taylor, Linda Jo; Adler, Douglas. G.

    2017-01-01

    Background and study aims Long-term data are limited regarding clinical outcomes of self-expanding metal stents as an alternative for surgery in the treatment of acute proximal MBO. The aim of this study was to compare the long-term outcomes of stenting to surgery for palliation in patients with incurable obstructive CRC for lesions proximal to the splenic flexure. Patients and methods Retrospective multicenter cohort study of obstructing proximal CRC patients with who underwent insertion of a SEMS (n = 69) or surgery (n = 36) from 1999 to 2014. The primary endpoint was relief of obstruction. Secondary endpoints included technical success, duration of hospital stay, early and late adverse events (AEs) and survival. Results Technical success was achieved in 62/69 (89.8 %) patients in the SEMS group and in 36 /36 (100 %) patients who underwent surgery (P = 0.09). In the SEMS group, 10 patients underwent stenting as a bridge to surgery and 59 underwent stent placement for palliation. Clinical relief was achieved in 78 % of patients with stenting and in 100 % of patients who underwent surgery (P group (7.2 % vs. 30.5 %, P = 0.003). Hospital mortality for the SEMS group was 0 % compared to 5.6 % in the surgery group (P = 0.11). Patients in the SEMS group had a significantly shorter median hospital stay (4 days) as compared to the surgery group (8 days) (P group (73.9 %) than the surgery group (97.3 %; P = 0.003). SEMS placement was associated with higher long-term complication rates compared to surgery (21 % and 11 % P = 0.27). Late SEMS AEs included occlusion (10 %), migration (5 %), and colonic ulcer (6 %). At 120 weeks, survival in the SEMS group was 5.6 % vs. 0 % in the surgery group (P = 0.8). Conclusions Technical and clinical success associated with proximal colonic obstruction are higher with surgery when compared to SEMS, but surgery is associated with longer hospital stays and more

  20. A randomized, prospective, two-center comparison of sirolimus-eluting stent and zotarolimus-eluting stent in acute ST-elevation myocardial infarction: The SEZE trial

    Institute of Scientific and Technical Information of China (English)

    Woo-Young Chung; Sang-Hyun Kim; In-Ho Chae; Joo-Hee Zo; Myung-A Kim; Dong-Ju Choi; Jeehoon Kang; Young-Seok Cho; Hae-Jun Park; Han-Mo Yang; Jae-Bin Seo; Jung-Won Suh; Kwang-Il Kim; Tae-Jin Youn

    2012-01-01

    Background The zotarolimus-eluting stent has shown larger in-stent late lumen loss compared to sirolimus-eluting stents in previous studies.However,this has not been thoroughly evaluated in ST elevation myocardial infarction.Methods This was a prospective,randomized,controlled trial evaluating angiographic outcomes in patients presenting with ST elevation myocardial infarction,treated with zotarolimus-eluting stents or sirolimus-eluting stents.From March 2007 to February 2009,122 patients were randomized to zotarolimus-eluting stents or sirolimus-eluting stents in a 1:1 fashion.The primary endpoint was 9-month in-stent late lumen loss confirmed by coronary angiography,and secondary endpoints were percent diameter stenosis,binary restenosis rate,major adverse cardiac events (a composite of cardiac death,non-fatal myocardial infarction,and target vessel revascularization),and late-acquired incomplete stent apposition.Results Angiographic in-stent late lumen loss was significantly higher in the zotarolimus-eluting stent group compared to the sirolimus-eluting stent group ((0.49±0.65) mm vs.(0.10±0.46) mm,P=0.001).Percent diameter stenosis at 9-month follow-up was also larger in the zotarolimus-eluting stent group ((30.0±17.9)% vs.(17.6±14.0)%,P <0.001).In-segment analysis showed similar findings.There were no significant differences in binary restenosis rate,major adverse cardiac events,and late-acquired incomplete stent apposition.Conclusions Compared to sirolimus-eluting stents,the zotarolimus-eluting stent is associated with significantly higher in-stent late lumen loss at 9-month angiographic follow-up in the treatment of ST elevation myocardial infarction.Although there was no significant difference in 1-year clinical outcomes,the clinical implication of increased late lumen loss should be further studied.

  1. Endovascular Mechanical Recanalisation After Intravenous Thrombolysis in Acute Anterior Circulation Stroke: The Impact of a New Temporary Stent

    Energy Technology Data Exchange (ETDEWEB)

    Fesl, Gunther, E-mail: gunther.fesl@med.uni-muenchen.de; Patzig, Maximilian; Holtmannspoetter, Markus [University of Munich, Department of Neuroradiology (Germany); Mayer, Thomas E. [University of Jena, Department of Neuroradiology (Germany); Pfefferkorn, Thomas; Opherk, Christian [University of Munich, Department of Neurology (Germany); Brueckmann, Hartmut [University of Munich, Department of Neuroradiology (Germany); Wiesmann, Martin [University Hospital, Department of Diagnostic and Interventional Neuroradiology (Germany)

    2012-12-15

    Purpose: Treatment of acute stroke by endovascular mechanical recanalisation (EMR) has shown promising results and continues to be further refined. We evaluated the impact of a temporary stent compared with our results using other mechanical devices. Materials and Methods: We analysed clinical and radiological data of all patients who were treated by EMR after intravenous thrombolysis for acute carotid T- and middle-cerebral artery (M1) occlusions at our centre between 2007 and 2011. A comparison was performed between those patients in whom solely the stent-retriever was applied (group S) and those treated with other devices (group C). Results: We identified 14 patients for group S and 16 patients for group C. Mean age, National Institute of Health Stroke Scale score, and time to treatment were 67.1 years and 16.5 and 4.0 h for group S and 61.1 years and 17.6 and 4.5 h for group C, respectively. Successful recanalisation (thrombolysis in cerebral infarction scores {>=}IIb) was achieved in 93% of patients in group S and 56% of patients in group C (P < 0.05). Mean recanalisation times for M1 occlusions were 23 min (group S) and 29 min (group C) and for carotid-T occlusions were 39 min (group S) and 50 min (group C), and 45% of the patients in group S and 33% in group C had a favourable outcome (Modified Rankin Scale score {<=}2). Conclusion: The findings suggest an improvement in recanalisation success by the application of a temporary stent compared with previously used devices. These results are to be confirmed by larger studies.

  2. Antithrombotic therapy in anticoagulated patients with atrial fibrillation presenting with acute coronary syndromes and/or undergoing percutaneous coronary intervention/stenting

    Directory of Open Access Journals (Sweden)

    Benjamin J. Wrigley

    2010-07-01

    Full Text Available The management of antithrombotic therapy in atrial fibrillation patients presenting with acute coronary syndrome and/or undergoing percutaneous coronary inter vention/stenting cannot be done according to a regimented common protocol, and stroke and bleeding risk stratification schema should be employed to individualize treatment options. A delicate balance is needed between the prevention of thromboembolism, against recurrent cardiac ischemia or stent thrombosis, and bleeding risk. New guidance from a consensus document of the European Society of Cardiology Working Group on Thrombosis, endorsed by the European Heart Rhythm Association and the European Association ofPercutaneous Cardiovascular Interventions on the management of Antithrombotic Therapy in Atrial Fibrillation Patients Presenting with Acute Coronary Syndrome and/or Undergoing Percutaneous Coronary Intervention/Stenting has sought to clarify some of the major issues and problems surrounding this practice, and will allow clinicians to make much more informed decisions when faced with treating such patients.

  3. Bioresorbable microporous stents deliver recombinant adenovirus gene transfer vectors to the arterial wall.

    Science.gov (United States)

    Ye, Y W; Landau, C; Willard, J E; Rajasubramanian, G; Moskowitz, A; Aziz, S; Meidell, R S; Eberhart, R C

    1998-01-01

    The use of intravascular stents as an adjunct for percutaneous transluminal revascularization is limited by two principal factors, acute thrombosis and neointimal proliferation, resulting in restenosis. To overcome these limitations, we have investigated the potential of microporous bioresorbable polymer stents formed from poly(L-lactic acid) (PLLA)/poly(epsilon-caprolactone) (PCL) blends to function both to provide mechanical support and as reservoirs for local delivery of therapeutic molecules and particles to the vessel wall. Tubular PLLA/PCL stents were fabricated by the flotation-precipitation method, and helical stents were produced by a casting/winding technique. Hybrid structures in which a tubular sheath is deposited on a helical skeleton were also generated. Using a two-stage solvent swelling technique, polyethylene oxide has been incorporated into these stents to improve hydrophilicity and water uptake, and to facilitate the ability of these devices to function as drug carriers. Stents modified in this manner retain axial and radial mechanical strength sufficient to stabilize the vessel wall against elastic recoil caused by vasoconstrictive and mechanical forces. Because of the potential of direct gene transfer into the vessel wall to ameliorate thrombosis and neointimal proliferation, we have investigated the capacity of these polymer stents to function in the delivery of recombinant adenovirus vectors to the vessel wall. In vitro, virus stock was observed to readily absorb into, and elute from these devices in an infectious form, with suitable kinetics. Successful gene transfer and expression has been demonstrated following implantation of polymer stents impregnated with a recombinant adenovirus carrying a nuclear-localizing betaGal reporter gene into rabbit carotid arteries. These studies suggest that surface-modified polymer stents may ultimately be useful adjunctive devices for both mechanical support and gene transfer during percutaneous

  4. Predictors of aortic growth in uncomplicated type B aortic dissection from the Acute Dissection Stent Grafting or Best Medical Treatment (ADSORB) database

    DEFF Research Database (Denmark)

    Kamman, Arnoud V; Brunkwall, Jan; Verhoeven, Eric L

    2017-01-01

    BACKGROUND: The high-risk patient cohort of uncomplicated type B aortic dissections (uTBADs) needs to be clarified. We compared uTBAD patients treated with best medical treatment (BMT), with and without aortic growth, from the Acute Dissection Stent Grafting or Best Medical Treatment (ADSORB) trial...

  5. Outcome of endoscopic self-expandable metal stents in acute malignant colorectal obstruction at a tertiary center

    Directory of Open Access Journals (Sweden)

    Eduardo Rodrigues-Pinto

    2015-09-01

    Full Text Available Background: Malignant colorectal obstruction (MCRO by advanced colonic cancer occurs in 8-13% of colonic cancer patients. Emergent surgery carries a high mortality and morbidity risk. Endoscopic self-expanding metal stents (SEMS may be used in acute MCRO. Aim: Evaluate clinical outcome of SEMS in acute MCRO and efficacy of SEMS placement considering fluoroscopy guidance. Methods: Retrospective study of patients with acute MCRO that placed SEMS in a 3 years period. Results: SEMS were placed in 47 patients, followed-up for a median time of 150 days. The intent of stenting was bridge to definitive surgery in 40% of the patients (n = 19 and palliation in the remaining 60% (n = 28. The location of the tumor did not influence the presence of lymph node involvement (p = 0.764 nor metastasis (p = 0.885. Mortality rate at year 1 was 61%. Survival was significantly higher in patients submitted later to combination therapy compared to chemotherapy, surgery or symptomatic treatment (p < 0.001. Fluoroscopy was used in 57% of the procedures. Clinical success was 79%. A second SEMS was needed during the procedure in 6% of the patients. Rate of early and late complications was 11% and 5%, respectively. Fluoroscopy guidance did not influence the occurrence of immediate (p = 0.385, early (p = 0.950 or late complications (p = 0.057. Thirty-three percent of patients underwent surgery at a later stage, with neo-adjuvant therapy in 18%. Conclusions: SEMS provide a relative safe and successful treatment in a palliative or bridge-to-surgery indication. No significant differences were found in SEMS placement success, early complications or late complications considering fluoroscopy guidance.

  6. Recanalization and Mortality Rates of Thrombectomy With Stent-Retrievers in Octogenarian Patients with Acute Ischemic Stroke

    Energy Technology Data Exchange (ETDEWEB)

    Parrilla, G., E-mail: gpr1972@gmail.com [Hospital Clínico Universitario Virgen de la Arrixaca, Service of Interventional Neuroradiology (Spain); Carreón, E. [Service of Neurology Hospital Clínico Universitario Virgen de la Arrixaca (Spain); Zamarro, J.; Espinosa de Rueda, M.; García-Villalba, B. [Hospital Clínico Universitario Virgen de la Arrixaca, Service of Interventional Neuroradiology (Spain); Marín, F. [Hospital Clínico Universitario Virgen de la Arrixaca, Department of Cardiology (Spain); Hernández-Fernández, F. [Hospital Clínico Universitario Virgen de la Arrixaca, Service of Interventional Neuroradiology (Spain); Morales, A. [Service of Neurology Hospital Clínico Universitario Virgen de la Arrixaca (Spain); Fernández-Vivas, M.; Núñez, R. [Hospital Clínico Universitario Virgen de la Arrixaca, Intensive Care Unit (Spain); Moreno, A. [Hospital Clínico Universitario Virgen de la Arrixaca, Service of Interventional Neuroradiology (Spain)

    2015-04-15

    BackgroundOur objective was to evaluate the effect of treatment with stent-retrievers in octogenarians suffering an acute ischemic stroke.MethodsA total of 150 consecutive patients with acute stroke who were treated with stent-retrievers between April 2010 and June 2012 were retrospectively reviewed. Patients were divided into those <80 years old (n = 116) and those ≥80 (n = 34). Baseline characteristics, procedure data, and endpoints (postprocedural NIHSS, death, and mRS at 3 months) were compared.ResultsHigh blood pressure, atrial fibrillation, and anticoagulation were more frequent in octogenarians (p = 0.01, 0.003, and 0.04 respectively). There were no differences between both groups regarding previous intravenous thrombolysis (32.4 vs. 48.3 %, p = 0.1), preprocedural NIHSS (18.1 vs. 16.8, p = 0.3), procedure time (74.5 (40–114) min vs. 63 (38–92) min, p = 0.2), revascularization time (380.5 (298–526.3) min vs. 350 (296.3–452.8), p = 0.3), TICI ≥ 2B (88.2 vs. 93.9 %, p = 0.1), and symptomatic haemorrhage (5.9 vs. 2.6 %, p = 0.3). Discharge NIHSS was higher in octogenarians (9.7 vs. 6.5, p = 0.03). Death and 3-month mRS ≥3 were more frequent in octogenarians (35.3 vs. 17.2 %, p = 0.02 and 73.5 vs. 37.1 %, p = 0.02). ICA-involvement and prolonged revascularization involved higher mortality (66.7 vs. 27.6 %, p = 0.03) and worse mRS (50 vs. 24.4 %, p = 0.06) in octogenarians.ConclusionsIn our series, treatment with stent-retrievers in octogenarians with acute ischemic stroke achieved good rates of recanalization but with a high mortality rate. ICA involvement and revascularization times beyond 6 hours associated to a worse prognosis. These data might be of value in the design of prospective studies evaluating the clinical efficacy of the endovascular treatments in octogenarians.

  7. Successful Endovascular Repair of an Iatrogenic Perforation of the Superficial Femoral Artery Using Self-Expanding Nitinol Supera Stents in a Patient with Acute Thromboembolic Limb Ischemia

    Directory of Open Access Journals (Sweden)

    Tom Eisele

    2016-01-01

    Full Text Available The treatment of acute thromboembolic limb ischemia includes well-established surgical thrombectomy procedures and, in recent times, also percutaneous rotational thrombectomy using Straub Rotarex® system. This modality not only enables efficient treatment of such thrombotic occlusion but also in rare cases may imply the risk of perforation of the occluded artery. Herein, we report the case of a perforation of the superficial femoral artery (SFA in an elderly female patient with thromboembolic limb ischemia. The perforation was successfully treated by implantation of self-expanding nitinol Supera stents and without the need for implantation of a stent graft.

  8. Refining stent technologies for femoral interventions.

    Science.gov (United States)

    Bosiers, M; Deloose, K; Callaert, J; Maene, L; Keirse, K; Verbist, J; Peeters, P

    2012-08-01

    Stents were created as a mechanical scaffold to prevent vessel recoil and luminal renarrowing after percutaneous transluminal angioplasty (PTA). In femoropopliteal arteries, indication for stent implantation remains a topic much debated on, especially in long lesion configurations. Ever since the first stents were introduced on the market, in-stent restenosis (ISR) has been an important issue. The evolution in stent design has known a major progression in the last decades from the first generation of stents, plagued with high fracture rates and low primary patency rates, to the design of newer stents to tackle these outcomes. More flexible and longer stents decreased the high fracture rates and drug-eluting stents offered a solution to the restenosis rates by local drug application. The difficult recrossibility of the lesion because of the presence of a permanent vascular scaffold is an obstacle that the drug-coated balloon (DCB) overcomes. Future perspectives in the treatment of femoropopliteal lesions are found in the bioresorbable stent implantation. The bioresorbable stent combines the advantages of a drug-eluting scaffolding stent without the remainder of a foreign object in the long-term. Further investigations in this area will eventually evolve in the creation of a superior endovascular treatment modality with high long-term patency rates and minimal detriments.

  9. Successful treatment of post-exertion acute myocardial infarction by primary angioplasty and stenting in a patient with antiphospholipid antibody syndrome.

    Science.gov (United States)

    Musuraca, Gerardo; Imperadore, Ferdinando; Terraneo, Clotilde; De Girolamo, Piergiuseppe; Cemin, Claudio; Bonmassari, Roberto; Vergara, Giuseppe

    2004-01-01

    Antiphospholipid syndrome is a disorder characterized by arterial and venous thromboses, thrombocytopaenia and stroke. Acute myocardial infarction is rarely associated with this syndrome. The treatment of these patients is a clinical challenge. This report is about a patient with antiphospholipid syndrome presenting with an acute myocardial infarction after an exercise test. The infarct-related coronary artery was successfully revascularized by primary angioplasty and stenting without any major bleeding complications. We think that the physical exertion could have favoured acute coronary thrombosis in this particular setting.

  10. Outcomes after primary coronary intervention with drug eluting stent implantation in diabetic patients with acute ST elevation myocardial infarction

    Institute of Scientific and Technical Information of China (English)

    ZHANG Qi; HU Jian; YANG Zhen-kun; ZHENG Ai-fang; ZHANG Xian; SHEN Wei-feng; SHEN Jie; ZHANG Rui-yan; QIU Jian-ping; LU Ji-de; ZHANG Yu; CHEN Yue-hua; ZHANG Jun-feng; ZHANG Jian-sheng

    2007-01-01

    Background Drug-eluting stent (DES) has been used widely for the treatment of patients with acute coronary syndrome with or without diabetes mellitus during percutaneous coronary intervention (PCI), but its long-term safety and efficacy in diabetic patients with acute ST elevation myocardial infarction (STEMI) remain uncertain. This study aimed to investigate the clinical outcomes after primary coronary intervention with DES implantation for diabetic patients with acute STEMI, compared with non-diabetic counterparts.Methods From December 2004 to March 2006, 56 consecutive diabetic patients (diabetic group) and 170 non-diabetic patients (non-diabetic group) with acute STEMI who underwent primary PCI with DES implantation in 3 hospitals were enrolled. Baseline clinical, angiographic, and procedural characteristics, as well as occurrence of major adverse cardiac event (MACE) including cardiac death, non-fatal recurrent myocardial infarction (re-MI) and target vessel revascularization (TVR) during hospitalization and one-year clinical follow-up were compared between the two groups.Results Patients in diabetic group were more hyperlipidemic (69.6% and 51.8%, P=0.03) and had longer time delay from symptom onset to admission ((364±219) minutes and (309±223) minutes,P=0.02) than those in non-diabetic group.The culprit vessel distribution, reference vessel diameter, and baseline TIMI flow grade were similar between the two groups, but multi-vessel disease was more common in diabetic than in non-diabetic group (82.1% and 51.2%, P<0.001).Despite similar TIMI flow grades between the two groups after stenting, the occurrence of TIMI myocardial perfusion grade (TMPG)≥2 was lower in diabetic group (75.0% vs 88.8% in non-diabetic groups, P=0.02). The MACE rate was similar during hospitalization between the two groups (5.4% vs 3.5%, P=0.72), but it was significantly higher in diabetic group (16.1%) during one-year follow-up, as compared with non-diabetic group (6.5%, P=0

  11. The HERMES recoil detector

    Energy Technology Data Exchange (ETDEWEB)

    Airapetian, A. [Giessen Univ. (Germany). Physikalisches Inst.; Michigan Univ., Ann Arbor, MI (United States). Randall Laboratory of Physics; Aschenauer, E.C. [DESY, Zeuthen (Germany); Belostotski, S. [B.P. Konstantinov Petersburg Nuclear Physics Insitute, Gatchina (Russian Federation)] [and others; Collaboration: HERMES Recoil Detector Group

    2013-02-15

    For the final running period of HERA, a recoil detector was installed at the HERMES experiment to improve measurements of hard exclusive processes in charged-lepton nucleon scattering. Here, deeply virtual Compton scattering is of particular interest as this process provides constraints on generalised parton distributions that give access to the total angular momenta of quarks within the nucleon. The HERMES recoil detector was designed to improve the selection of exclusive events by a direct measurement of the four-momentum of the recoiling particle. It consisted of three components: two layers of double-sided silicon strip sensors inside the HERA beam vacuum, a two-barrel scintillating fibre tracker, and a photon detector. All sub-detectors were located inside a solenoidal magnetic field with an integrated field strength of 1Tm. The recoil detector was installed in late 2005. After the commissioning of all components was finished in September 2006, it operated stably until the end of data taking at HERA end of June 2007. The present paper gives a brief overview of the physics processes of interest and the general detector design. The recoil detector components, their calibration, the momentum reconstruction of charged particles, and the event selection are described in detail. The paper closes with a summary of the performance of the detection system.

  12. Impact of baseline characteristics on outcomes of carotid artery stenting in acute ischemic stroke patients

    Directory of Open Access Journals (Sweden)

    Yu CS

    2016-03-01

    Full Text Available Cheng-Sheng Yu,1,* Chih-Ming Lin,2,3,* Chi-Kuang Liu,4 Henry Horng-Shing Lu1 1Institute of Statistics and Big Data Research Center, National Chiao Tung University, Hsinchu, 2Stroke Centre and Department of Neurology, Chunghua Christian Hospital, Chunghua, 3Graduate Institute of Biological Science and Technology, National Chiao Tung University, Hsinchu, 4Department of Medical Imaging, Chunghua Christian Hospital, Chunghua, Taiwan, Republic of China *These authors contributed equally to this work Abstract: Carotid artery stenting is an effective treatment for ischemic stroke patients with moderate-to-severe carotid artery stenosis. However, the midterm outcome for patients undergoing this procedure varies considerably with baseline characteristics. To determine the impact of baseline characteristics on outcomes following carotid artery stenting, data from 107 eligible patients with a first episode of ischemic stroke were collected by retrospective chart review. A modified Rankin Scale (mRS was used to divide patients into two baseline groups, mRS ≤2 and mRS >2. A three-step decision-tree statistical analysis was conducted. After weighting the decision-tree parameters, the following impact hierarchy was obtained: admission low-density lipoprotein, gouty arthritis, chronic kidney disease, ipsilateral common carotid artery resistance index, contralateral ophthalmic artery resistance index, sex, and dyslipidemia. The finite-state machine model demonstrated that, in patients with baseline mRS ≤2, 46% had an improved mRS score at follow-up, whereas 54% had a stable mRS score. In patients with baseline mRS >2, a stable mRS score was observed in 75%, improved score in 23%, and a poorer score in 2%. Admission low-density lipoprotein was the strongest predictive factor influencing poststenting outcome. In addition, our study provides further evidence that carotid artery stenting can be of benefit in first-time ischemic stroke patients with baseline m

  13. Biocompatibility of Coronary Stents

    Directory of Open Access Journals (Sweden)

    Thamarasee M. Jeewandara

    2014-01-01

    Full Text Available Cardiovascular disease is the dominant cause of mortality in developed countries, with coronary artery disease (CAD a predominant contributor. The development of stents to treat CAD was a significant innovation, facilitating effective percutaneous coronary revascularization. Coronary stents have evolved from bare metal compositions, to incorporate advances in pharmacological therapy in what are now known as drug eluting stents (DES. Deployment of a stent overcomes some limitations of balloon angioplasty alone, but provides an acute stimulus for thrombus formation and promotes neointimal hyperplasia. First generation DES effectively reduced in-stent restenosis, but profoundly delay healing and are susceptible to late stent thrombosis, leading to significant clinical complications in the long term. This review characterizes the development of coronary stents, detailing the incremental improvements, which aim to attenuate the major clinical complications of thrombosis and restenosis. Despite these enhancements, coronary stents remain fundamentally incompatible with the vasculature, an issue which has largely gone unaddressed. We highlight the latest modifications and research directions that promise to more holistically design coronary implants that are truly biocompatible.

  14. Finite element analyses for design evaluation of biodegradable magnesium alloy stents in arterial vessels

    Energy Technology Data Exchange (ETDEWEB)

    Wu Wei [Laboratory of Biological Structure Mechanics, Structural Engineering Department, Politecnico di Milano, Piazza Leonardo da Vinci, 32, 20133 Milan (Italy); Gastaldi, Dario, E-mail: dario.gastaldi@polimi.it [Laboratory of Biological Structure Mechanics, Structural Engineering Department, Politecnico di Milano, Piazza Leonardo da Vinci, 32, 20133 Milan (Italy); Yang Ke; Tan Lili [Division of Specialized Materials and Devices, Institute of Metal Research, Chinese Academy of Sciences, Shenyang (China); Petrini, Lorenza; Migliavacca, Francesco [Laboratory of Biological Structure Mechanics, Structural Engineering Department, Politecnico di Milano, Piazza Leonardo da Vinci, 32, 20133 Milan (Italy)

    2011-12-15

    Biodegradable magnesium alloy stents (MAS) can provide a great benefit for diseased vessels and avoid the long-term incompatible interactions between vessels and permanent stent platforms. However, the existing MAS showed insufficient scaffolding to the target vessels due to short degradation time. In this study, a three dimensional finite element model combined with a degradable material model of AZ31 (Al 0.03, Zn 0.01, Mn 0.002 and Mg balance, mass percentage) was applied to three different MAS designs including an already implanted stent (Stent A), an optimized design (Stent B) and a patented stent design (Stent C). One ring of each design was implanted through a simulation in a vessel model then degraded with the changing interaction between outer stent surface and the vessel. Results showed that a proper stent design (Stent B) can lead to an increase of nearly 120% in half normalized recoil time of the vessel compared to the Stent A; moreover, the expectation that the MAS design, with more mass and optimized mechanical properties, can increase scaffolding time was verified numerically. The Stent C has more materials than Stent B; however, it only increased the half normalized recoil time of the vessel by nearly 50% compared to the Stent A because of much higher stress concentration than that of Stent B. The 3D model can provide a convenient design and testing tool for novel magnesium alloy stents.

  15. Endoscopic ultrasound-guided gallbladder drainage for acute cholecystitis: Long-term outcomes after removal of a self-expandable metal stent

    Science.gov (United States)

    Kamata, Ken; Takenaka, Mamoru; Kitano, Masayuki; Omoto, Shunsuke; Miyata, Takeshi; Minaga, Kosuke; Yamao, Kentaro; Imai, Hajime; Sakurai, Toshiharu; Watanabe, Tomohiro; Nishida, Naoshi; Kudo, Masatoshi

    2017-01-01

    AIM To assess the long-term outcomes of this procedure after removal of self-expandable metal stent (SEMS). The efficacy and safety of endoscopic ultrasound-guided gallbladder drainage (EUS-GBD) with SEMS were also assessed. METHODS Between January 2010 and April 2015, 12 patients with acute calculous cholecystitis, who were deemed unsuitable for cholecystectomy, underwent EUS-GBD with a SEMS. EUS-GBD was performed under the guidance of EUS and fluoroscopy, by puncturing the gallbladder with a needle, inserting a guidewire, dilating the puncture hole, and placing a SEMS. The SEMS was removed and/or replaced with a 7-Fr plastic pigtail stent after cholecystitis improved. The technical and clinical success rates, adverse event rate, and recurrence rate were all measured. RESULTS The rates of technical success, clinical success, and adverse events were 100%, 100%, and 0%, respectively. After cholecystitis improved, the SEMS was removed without replacement in eight patients, whereas it was replaced with a 7-Fr pigtail stent in four patients. Recurrence was seen in one patient (8.3%) who did not receive a replacement pigtail stent. The median follow-up period after EUS-GBD was 304 d (78-1492). CONCLUSION EUS-GBD with a SEMS is a possible alternative treatment for acute cholecystitis. Long-term outcomes after removal of the SEMS were excellent. Removal of the SEMS at 4-wk after SEMS placement and improvement of symptoms might avoid migration of the stent and recurrence of cholecystitis due to food impaction. PMID:28216973

  16. Minimally invasive direct coronary artery bypass plus coronary stent for acute coronary syndrome: a case report

    Institute of Scientific and Technical Information of China (English)

    Caiyi Lu; Gang Wang; Qi Zhou; Jinwen Tian; Lei Gao; Shenhua Zhou; Jinyue Zhai; Rui Chen; Zhongren Zhao; Cangqing Gao; Shiwen Wang; Yuxiao Zhang; Ming Yang; Qiao Xue; Cangsong Xiao; Wei Gao; Yang Wu

    2008-01-01

    A 69-year old female patient was admitted because of 3 days of worsened chest pain.Coronary angiography showed60% stenosis of distal left main stem,chronic total occlusion of left anterior descending (LAD),70% stenosis at the ostium of a smallleft circumflex,70-90%stenosis at the paroxysmal and middle part of a dominant fight coronary artery (RCA),and a normal left internalmammary artery (LIMA) with normal origination and orientation.Percutaneous intervention was attempted but failed on the occludedlesion of LAD.The patient received minimally invasive direct coronary artery bypass (MIDCAB) with left LIMA isolation by Davincirobot.Eleven days later,the RCA lesion was treated by Sirolimus Rapamicin eluting stents implantation percutaneously.Then thepatient was discharged uneventfully after 3 days hospitalization.Our experience suggests that two stop shops of hybrid technique befeasible and safe in the treatment of elderly patient with multiple coronary diseases.

  17. Aspiration Thrombectomy and Drug-Eluting Stent Implantation Decrease the Occurrence of Angina Pectoris One Year After Acute Myocardial Infarction.

    Science.gov (United States)

    Lee, Wei-Chieh; Fang, Chih-Yuan; Chen, Huang-Chung; Hsueh, Shu-Kai; Chen, Chien-Jen; Yang, Cheng-Hsu; Yip, Hon-Kan; Hang, Chi-Ling; Wu, Chiung-Jen; Fang, Hsiu-Yu

    2016-04-01

    Angina pectoris is a treatable symptom that is associated with mortality and decreased quality of life. Angina eradication is a primary care goal of care after an acute myocardial infarction (AMI). Our aim was to evaluate factors influencing angina pectoris 1 year after an AMI.From January 2005 to December 2013, 1547 patient received primary percutaneous intervention in our hospital for an acute ST-segment elevation myocardial infarction (MI). Of these patients, 1336 patients did not experience post-MI angina during a 1-year follow-up, and 211 patients did. Univariate and multivariate logistic regression analyses were performed to identify the factors influencing angina pectoris 1 year after an AMI. Propensity score matched analyses were performed for subgroups analyses.The average age of the patients was 61.08 ± 12.77 years, with a range of 25 to 97 years, and 82.9% of the patients were male. During 1-year follow-up, 13.6% of the patients experienced post-MI angina. There was a longer chest pain-to-reperfusion time in the post-MI angina group (P = 0.01), as well as a higher fasting sugar level, glycohemoglobin (HbA1C), serum creatinine, troponin-I and creatine kinase MB (CK-MB). The post-MI angina group also had a higher prevalence of multiple-vessel disease. Manual thrombectomy, and distal protective device and intracoronary glycoprotein IIb/IIIa inhibitor injection were used frequently in the no post-MI angina group. Antiplatelet agents and post-MI medication usage were similar between the 2 groups. Multivariate logistic regression analyses demonstrated that prior MI was a positive independent predictor of occurrence of post-MI angina. Manual thrombectomy use and drug-eluting stent implantation were negative independent predictors of post-MI angina. Higher troponin-I and longer chest pain-to-reperfusion time exhibited a trend toward predicting post-MI angina.Prior MIs were strong, independent predictors of post-MI angina. Manual thrombectomy and drug

  18. Acute thrombosis during left main stenting using tap technique in a patient presenting with non-ST-segment elevation acute coronary syndrome

    Energy Technology Data Exchange (ETDEWEB)

    Natarajan, Deepak, E-mail: deepaknatarajan@me.com

    2015-06-15

    This case reports the sudden development of large burden of thrombi in the left anterior descending coronary artery immediately following distal left main stenting using TAP technique in a middle aged man who presented with non ST-segment elevation acute coronary syndrome despite having been administered 7,500 units of unfractionated heparin and being given 325 mg of aspirin and 60 mg of prasugrel prior to the procedure. The thrombi were managed effectively by giving an intra-coronary high bolus dose of tirofiban (25 mcg/kg) without the need for catheter thrombus extraction. Tirofiban intra-venous infusion was maintained for 18 hours, and the patient was discharged in stable condition on the third day. Importantly there is no controlled study on upstream administration of glycoprotein IIb/IIIa inhibitors in addition to the newer more potent anti-platelet agents in patients with unprotected distal left main disease presenting with non ST-segment elevation acute coronary syndrome, nor is there any data on safety and efficacy of mandatory usage of injectable anti-platelet agents at the start of a procedure in a catheterization laboratory in such a setting.

  19. Infolding of covered stents used for aortic coarctation: report of two cases.

    Science.gov (United States)

    Wan, Andrea W; Lee, Kyong-Jin; Benson, Lee N

    2014-01-01

    Covered stents have been used for the treatment of aortic coarctation to protect the arterial wall during dilation. Early results have shown them to be safe and effective. We report two cases of infolding of the proximal edge of a covered aortic coarctation stent. Management required implantation of a second stent. Poor stent apposition to the vessel wall and/or recoil may allow conditions for these events to occur.

  20. Stent graft placement for dysfunctional arteriovenous grafts

    Energy Technology Data Exchange (ETDEWEB)

    Jeon, Gyeong Sik [Dept. of Radiology, CHA Bundang Medical Center, College of Medicine, CHA University, Seongnam (Korea, Republic of); Shin, Byung Seok; Ohm, Joon Young; Ahn, Moon Sang [Chungnam National University Hospital, Daejeon (Korea, Republic of)

    2015-07-15

    This study aimed to evaluate the usefulness and outcomes of stent graft use in dysfunctional arteriovenous grafts. Eleven patients who underwent stent graft placement for a dysfunctional hemodialysis graft were included in this retrospective study. Expanded polytetrafluoroethylene covered stent grafts were placed at the venous anastomosis site in case of pseudoaneurysm, venous laceration, elastic recoil or residual restenosis despite the repeated angioplasty. The patency of the arteriovenous graft was evaluated using Kaplan-Meier analysis. Primary and secondary mean patency was 363 days and 741 days. Primary patency at 3, 6, and 12 months was 82%, 73%, and 32%, respectively. Secondary patency at the 3, 6, 12, 24, and 36 months was improved to 91%, 82%, 82%, 50%, and 25%, respectively. Fractures of the stent graft were observed in 2 patients, but had no effect on the patency. Stent graft placement in dysfunctional arteriovenous graft is useful and effective in prolonging graft patency.

  1. Heparin-Coated Coronary Stents.

    Science.gov (United States)

    van Der Giessen WJ; van Beusekom HM; Larsson; Serruys

    1999-09-01

    The development of the heparin-coated (HC)-stent should be viewed against the backdrop of the early unfavorable results with noncoated stents in the pre-intravascular ultrasound and pre-ticlopidine era. Notwithstanding, results of pilot and randomized trials show a surprisingly low incidence of (sub)acute stent thrombosis under challenging circumstances, such as acute coronary syndromes. Considering the quite low incidence of early complications with noncoated second-generation stents, it may require large trials to prove the clinical efficacy of the heparin- coating against noncoated devices. However, even if the "added value" of the heparin-coating will never be clinically proven, it has helped to enhance the penetration of stent therapy in interventional cardiology. Unlike the situation in 1992, very few cardiologists will now disagree with the statement that stents contribute to the state-of-the-art treatment of patients with angina pectoris or acute myocardial infarction. A preliminary comparison of available trials also suggests that the heparin-coated Palmaz-Schatz stent (Cordis Corp., Waterloo, Belgium) is as effective as the noncoated stent plus abciximab treatment.

  2. IVUS-Guided Implantation of Bioresorbable Vascular Scaffolds for Very Late Paclitaxel Stent Thrombosis

    Science.gov (United States)

    Lin, Zhe-Zhong; Chang, Wei-Ting; Chiang, Chun-Yen; Chen, Zhih-Cherng; Ku, Po-Ming

    2017-01-01

    Bioresorbable vascular scaffold (BVS) implantation has been shown to be safe in patients with stable coronary disease, and effective against the thrombotic lesion and the in-stent restenosis (ISR) of the drug-eluting stent (DES). BVSs have the advantages of a snow racket concept, positive vessel remodeling, and better conformability compared with DES in acute coronary syndrome (ACS). We report on a young patient with ST-elevation myocardial infarction (STEMI) who presented to our emergency department arising from very late stent thrombosis (VLST) of a 2.5 × 28 mm paclitaxel-eluting stent (Coroflex® Please) three years after its implantation. After the patient was treated with balloon dilation, intravascular ultrasound (IVUS) revealed a short segment of a guide wire outside the DES mesh. Two BVSs were implanted to prevent a DES recoil. Post-scaffold-implantation IVUS showed adequately expanded strut of BVSs. Six months later, optical coherence tomography (OCT) revealed that some segments of the scaffold had been absorbed and that there was no in-scaffold restenosis. The patient had not complained about angina during the out-patient clinic follow-up. This is the first report of successful BVS implantation for a STEMI patient attributable to DES VLST. PMID:28115812

  3. Balloon-guided navigation technique to perform stenting in an acutely angled anterior cerebral artery.

    Science.gov (United States)

    Cohen, José E; Gomori, John M; Moscovici, Samuel; Itshayek, Eyal

    2012-03-01

    The complex anatomic features of wide-necked anterior communicating artery aneurysms represent an endovascular challenge. Compliant balloons and microstents are frequently required to achieve aneurysm occlusion. When the angle between the A1 and A2 segments is acute, microcatheter navigation is hazardous, and may be difficult or sometimes impossible with standard techniques. We present our technique using a support balloon to facilitate guidewire engagement and navigation of A2, and to assist with microcatheterization in this unfavorable vascular anatomy.

  4. Bronchial stents

    Directory of Open Access Journals (Sweden)

    Ibrahim Emad

    2006-01-01

    Full Text Available Bronchial stents are mostly used as a Palliative relief of symptoms often caused by airway obstruction, It is also used for sealing of stump fistulas after pneumonectomy and dehiscence after bronchoplastic operations. Advances in airway prosthetics have provided a variety of silicone stents, expandable metal stents, and pneumatic dilators, enabling the correction of increasingly complex anatomical problems. Several series have been published describing the application and results of these techniques. This manuscript reviews the historical development of stents, types, indication, outcome, and complications. Alternative therapies for tracheobronchial stenting were also reviewed

  5. Transient ST-segment elevation in precordial leads by acute marginal branch occlusion during stent implantation.

    Science.gov (United States)

    Arzola, Leidimar Carballo; Esteban, Marcos T Rodríguez; Niebla, Javier García

    2016-01-01

    The isolated right ventricular infarction is a rare entity. Our case presented a selective occlusion of an acute marginal branch that supplies the right ventricular free wall with isolated ST elevation in precordial leads simulating an occlusion of the left anterior descending artery and without pseudonormalization in inferior due to the non-involvement of the main branch in the ischemic process. Our case clearly illustrates a rare differential diagnosis when a new ST segment elevation appears in earlier precordial leads in patients with symptoms of myocardial ischemia.

  6. Implanted central venous catheter-related acute superior vena cava syndrome: management by metallic stent and endovascular repositioning of the catheter tip

    Energy Technology Data Exchange (ETDEWEB)

    Qanadli, S.D.; Mesurolle, B.; Sissakian, J.F.; Chagnon, S.; Lacombe, P. [Service de Radiologie, Hopital Ambroise Pare, 92 - Boulogne (France)

    2000-08-01

    We describe a case of a 49-year-old woman with stage-IIIB lung adenocarcinoma who experienced an acute superior vena cava syndrome related to an implanted central venous catheter without associated venous thrombosis. The catheter was surgically implanted for chemotherapy. Superior vena cava syndrome appeared after the procedure and was due to insertion of the catheter through a subclinical stenosis of the superior vena cava. Complete resolution of the patient's symptoms was obtained using stent placement and endovascular repositioning of the catheter tip. (orig.)

  7. Very late bare-metal stent thrombosis, rare but stormy!

    LENUS (Irish Health Repository)

    Ali, Mohammed

    2011-08-01

    Recurrent in-stent thrombosis is rarely reported, with catastrophic clinical consequences of either acute coronary syndrome or death. We present a case of recurrent in-stent thrombosis with its outcome and a concise literature review.

  8. Microfabrication and nanotechnology in stent design.

    Science.gov (United States)

    Martinez, Adam W; Chaikof, Elliot L

    2011-01-01

    Intravascular stents were first introduced in the 1980s as an adjunct to primary angioplasty for management of early complications, including arterial dissection, or treatment of an inadequate technical outcome due to early elastic recoil of the atherosclerotic lesion. Despite the beneficial effects of stenting, persistent high rates of restenosis motivated the design of drug-eluting stents for delivery of agents to limit the proliferative and other inflammatory responses within the vascular wall that contribute to the development of a restenotic lesion. These strategies have yielded a significant reduction in the incidence of restenosis, but challenges remain, including incomplete repair of the endothelium at the site of vascular wall injury that may be associated with a late risk of thrombosis. A failure of vessel wall healing has been attributed primarily to the use of polymeric stent coatings, but the effects of the eluted drug and other material properties or design features of the stent cannot be excluded. Improvements in stent microfabrication, as well as the introduction of alternative materials may help to address those limitations that inhibit stent performance. This review describes the application of novel microfabrication processes and the evolution of new nanotechnologies that hold significant promise in eliminating existing shortcomings of current stent platforms.

  9. Recoiling Black Holes in Quasars

    CERN Document Server

    Bonning, E W; Salviander, S

    2007-01-01

    Recent simulations of merging black holes with spin give recoil velocities from gravitational radiation up to several thousand km/s. A recoiling supermassive black hole can retain the inner part of its accretion disk, providing fuel for a continuing QSO phase lasting millions of years as the hole moves away from the galactic nucleus. One possible observational manifestation of a recoiling accretion disk is in QSO emission lines shifted in velocity from the host galaxy. We have examined QSOs from the Sloan Digital Sky Survey with broad emission lines substantially shifted relative to the narrow lines. We find no convincing evidence for recoiling black holes carrying accretion disks. We place an upper limit on the incidence of recoiling black holes in QSOs of 4% for kicks greater than 500 km/s and 0.35% for kicks greater than 1000 km/s line-of-sight velocity.

  10. A new removable airway stent

    Directory of Open Access Journals (Sweden)

    Tore Amundsen

    2016-09-01

    Full Text Available Background: Malignant airway obstruction is a feared complication and will most probably occur more frequently in the future because of increasing cancer incidence and increased life expectancy in cancer patients. Minimal invasive treatment using airway stents represents a meaningful and life-saving palliation. We present a new removable airway stent for improved individualised treatment. Methods: To our knowledge, the new airway stent is the world's first knitted and uncovered self-expanding metal stent, which can unravel and be completely removed. In an in vivo model using two anaesthetised and spontaneously breathing pigs, we deployed and subsequently removed the stents by unravelling the device. The procedures were executed by flexible bronchoscopy in an acute and a chronic setting – a ‘proof-of-principle’ study. Results: The new stent was easily and accurately deployed in the central airways, and it remained fixed in its original position. It was easy to unravel and completely remove from the airways without clinically significant complications. During the presence of the stent in the chronic study, granulation tissue was induced. This tissue disappeared spontaneously with the removal. Conclusions: The new removable stent functioned according to its purpose and unravelled easily, and it was completely removed without significant technical or medical complications. Induced granulation tissue disappeared spontaneously. Further studies on animals and humans are needed to define its optimal indications and future use.

  11. Impact of admission creatinine level on clinical outcomes of patients with acute ST-elevation myocardial infarction undergoing primary percutaneous coronary intervention with drug-eluting stent implantation

    Institute of Scientific and Technical Information of China (English)

    ZHANG Qi; ZHANG Rui-yan; SHEN Jie; ZHANG Jian-sheng; HU Jian; YANG Zheng-kun; ZHANG Xian; ZHENG Ai-fang; SHEN Wei-feng

    2008-01-01

    Background Prognosis of patients with acute ST-elevation myocardial infarction (STEMI) and renal dysfunction (RD) who received primary percutaneous coronary intervention (PCI) has not been fully investigated in the drug-eluting stent (DES) era.This study aimed to evaluate the impact of admission serum creatinine level on short-term outcomes in patients with acute STEMI undergoing DES-based primary PCI.Methods Primary PCI with DES implantation was attempted in 619 consecutive STEMI patients within 12 hours of symptom onset.Among them,86 patients had a serum creatinine level >115 μmol/L on admission (RD group),and the remaining 533 patients had normal renal function (non-RD group).The primary endpoint was 30-day major adverse cardiac events (MACE,including death,non-fatal reinfarction,and target vessel revascularization),and the secondary endpoint was subacute stent thrombosis.Results Patients in the RD group were older than those in the non-RD group.There are more female patients in the RD group and they had a history of hypertension,myocardial infarction and revascularization.The occurrence rates of Killip class ≥2 (29.1% vs 18.6%,P=0.02) and multi-vessel (62.8% vs 44.5%,P=0.001) and triple vessel disease (32.6% vs 18.2%,P=0.002),in-hospital mortality (9.3% vs 3.8%,P=0.03),and MACE rate during hospitalization (17.4% vs 7.7%,P=0.006) were higher in the RD group than those in the non-RD group.At a 30-day clinical follow-up,the MACE-free survival rate was significantly reduced in the RD group (76.7% vs 89.9%,P=0.0003).Angiographic stent thrombosis occurred in 3 (3.5%) and 7 (1.3%) of patients in the RD group and non-RD group,respectively (P=0.15).Multivariate analysis revealed that the serum creatinine level≥115 μmol/L on admission was an independent predictor for MACE rate at a 30-day follow-up (Hazard ratio (HR) 3.31,95% CI 1.19-9.18,P<0.001).Conclusion Despite similar prevalence of stent thrombosis at a 30-day clinical follow-up,the short-term prognosis of

  12. Subacute coronary stent thrombosis in a patient with angina treated with double antiplatelet drugs for six days

    Institute of Scientific and Technical Information of China (English)

    XUE Feng; YANG Xiang-jun; CHENG Xu-jie; HUI Jie; JIANG Ting-bo; CHEN Tan; LIU Zhi-hua; SONG Jian-ping; JIANG Wen-ping

    2009-01-01

    @@ Stent implantation has been a great advance in percutaneous coronary intervention (PCI), decreasing the frequency of acute closure and restenosis. But stent thrombosis is a severe complication of this therapy regardless of the stent type: bare-metal stent (BMS) and drug-eluting stent (DES).

  13. Maximizing benefit of drug-eluting stent by direct coronary stenting because of further reduction of inflammatory response

    Institute of Scientific and Technical Information of China (English)

    LI Jian-jun; GAO Run-lin

    2009-01-01

    @@ Coronary stents have been used as standard mechanical devices for percutaneous coronary intervention (PCI) in patients with coronary artery disease (CAD).1-3 They provide vessel wall scaffolding and prevent early elastic recoil and restenosis, which are major limitations of balloon angioplasty.4,5 Consequently, coronary stenting has a higher successful rate of PCI and improves the clinical outcome of the patients with CAD.6

  14. A 2-step optical coherence tomography guided therapeutic approach to acute myocardial infarction secondary to stent thrombosis

    Energy Technology Data Exchange (ETDEWEB)

    Bogale, Nigussie, E-mail: nigussie.bogale@lyse.net [Vancouver General Hospital, Division of Cardiology University of British Columbia, Vancouver, BC (Canada); Stavanger University Hospital, Department of Cardiology, Stavanger (Norway); Lempereur, Mathieu; Fung, Anthony Y. [Vancouver General Hospital, Division of Cardiology University of British Columbia, Vancouver, BC (Canada)

    2016-07-15

    Myocardial infarction secondary to stent thrombosis has high mortality and recurrence rate. Emergency PCI has high risk of no-reflow. We used a 2-step approach of early recanalization with minimal mechanical intervention followed by delayed PCI 1–2 days later guided by Optical Coherence Tomography (OCT). From October 2011 to December 2013, we treated 5 patients with this approach. Time from early recanalization to the delayed definitive PCI was 1 day (median, range 1–3 days). All the OCT images were diagnostic with a clear view of the underlying structures. Summary: A 2-step approach to treat stent thrombosis appears beneficial with low incidence of peri-procedural thrombosis or no-reflow phenomena during the second step, and superb OCT imaging.

  15. Arterial healing following primary PCI using the Absorb everolimus-eluting bioresorbable vascular scaffold (Absorb BVS) versus the durable polymer everolimus-eluting metallic stent (XIENCE) in patients with acute ST-elevation myocardial infarction

    DEFF Research Database (Denmark)

    Räber, Lorenz; Onuma, Yoshinobu; Brugaletta, Salvatore

    2015-01-01

    Aims: The Absorb bioresorbable vascular scaffold (Absorb BVS) provides similar clinical outcomes compared with a durable polymer-based everolimus-eluting metallic stent (EES) in stable coronary artery disease patients. ST-elevation myocardial infarction (STEMI) lesions have been associated...... with delayed arterial healing and impaired stent-related outcomes. The purpose of the present study is to compare directly the arterial healing response, angiographic efficacy and clinical outcomes between the Absorb BVS and metallic EES. Methods and results: A total of 191 patients with acute STEMI were...... randomly allocated to treatment with the Absorb BVS or a metallic EES 1:1. The primary endpoint is the neointimal healing (NIH) score, which is calculated based on a score taking into consideration the presence of uncovered and malapposed stent struts, intraluminal filling defects and excessive neointimal...

  16. 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.

  17. Acute Portal Vein Thrombosis and Massive Necrosis of the Liver. An Unusual Complication After Stenting for Chronic Pancreatitis

    Directory of Open Access Journals (Sweden)

    Velayutham Vimalraj

    2006-11-01

    Full Text Available Context ERCP can provide information which is invaluable in managing chronic pancreatitis but it is associated withinfrequent, although significant, complications and rare mortality. The complications uniquely associated withdiagnostic ERCP include pancreatitis and sepsis (primary cholangitis. Case report A 32-year-old man presented with severe upper abdominal pain radiating to the back, associated with vomiting and abdominal distension. The patient was diagnosed as having had chronic calcific pancreatitis recently and had undergone ERCP with pancreatic duct stenting elsewhere. Two days after the procedure, the patient developed severe abdominal pain, vomiting and abdominal distention, and patient was referred to our hospital 7 days after the procedure. Investigation revealed massive liver necrosis and portal vein thrombosis. This patient had a life-threatening complication following pancreatic duct stenting for chronic pancreatitis and was managed medically.Conclusion Therapeutic pancreatic endoscopy procedures are technically demanding and should be restricted to highvolume centers. There is a continuing need for evaluation and comparison with alternative strategies. In a good surgical candidate, it is better to avoid stenting.

  18. Stent malapposition, as a potential mechanism of very late stent thrombosis after bare-metal stent implantation: A case report

    Energy Technology Data Exchange (ETDEWEB)

    Higuma, Takumi, E-mail: higuma@cc.hirosaki-u.ac.jp; Abe, Naoki; Hanada, Kenji; Yokoyama, Hiroaki; Tomita, Hirofumi; Okumura, Ken

    2014-04-15

    A 90-year-old man was admitted to our hospital with acute ST-segment elevation myocardial infarction. He had a history of post-infarction angina pectoris 79 months ago and had a bare-metal stent (BMS) implanted in the proximal left anterior descending artery at our hospital. Emergent coronary angiography demonstrated thrombotic occlusion in the previously stented segment. After catheter thrombectomy, antegrade flow was restored, but 90% stenosis with haziness persisted in the proximal and distal portions of the previously stented segment. Intravascular ultrasound imaging showed interstrut cavities or stent malapposition at the proximal and distal sites of stented segment. In close proximity to the sites, residual thrombi were also observed. Optical coherence tomography (OCT) demonstrated neither lipid-laden neointimal tissue nor rupture but clearly demonstrated residual thrombus adjacent to the malapposed region in addition to the stent malapposition. PCI with balloon was successfully performed and stent apposition was confirmed by OCT. Stent malapposition is an unusual mechanism of very late stent thrombosis after BMS implantation. OCT can clearly reveal the etiology of stent thrombosis.

  19. Recoiling DNA Molecule Simulation & Experiment

    CERN Document Server

    Neto, J C; Mesquita, O N; Neto, Jose Coelho; Dickman, Ronald

    2002-01-01

    Many recent experiments with single DNA molecules are based on force versus extension measurements and involve tethering a microsphere to one of its extremities and the other to a microscope coverglass. In this work we show that similar results can also be obtained by studying the recoil dynamics of the tethered microspheres. Computer simulations of the corresponding Langevin equation indicate which assumptions are required for a reliable analysis of the experimental recoil curves. We have measured the persistence length A of single naked DNA molecules and DNA-Ethidium Bromide complexes using this approach.

  20. Open triple-branched stent graft applied to patient of acute type a aortic dissection with Aberrant Right Subclavian Artery

    OpenAIRE

    Guo, Changfa; Zhu, Kai; Xu, Demin; Wang, Chunsheng

    2013-01-01

    A 57-year-old Chinese male patient presented with Standford type A aortic dissection with an aberrant right subclavian artery (ARSA). At operation, the ascending aorta was replaced by a mono–branch vascular prosthesis with the branch bypassing to the ARSA; the triple-branched stent graft was inserted into the true lumen of the arch and proximal descending aorta (covering the origin of the ARSA) with each sidearm graft being positioned into the aortic branches; and then its proximal end was su...

  1. Effect of cause of iliac vein stenosis and extent of thrombus in the lower extremity on patency of iliac venous stent placed after catheter-directed thrombolysis of acute deep venous thrombosis in the lower extremity

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Sung Il; Choi, Young Ho; Yoon, Chang Jin; Lee, Min Woo; Chung, Jin Wook; Park, Jae Hyung [College of Medicine, Seoul National Univ., Seoul (Korea, Republic of)

    2003-10-01

    To assess the CT findings of acute deep venous thrombosis (DVT) in a lower extremity prior to catheter-directed thrombolysis, and to evaluate their relevance to the patency of an iliac venous stent placed with the help of CT after catheter-directed thrombolysis of DVT. Fourteen patients [M:F=3:11; age, 33-68 (mean, 50.1) years] with acute symptomatic DVD of a lower extremity underwent CT before and after catheter-directed thrombolysis using an iliac venous stent. The mean duration of clinical symptoms was 5.0 (range, 1-14 days. The CT findings prior to thrombolysis were evaluated in terms of their anatomic cause and the extent of the thrombus, and in all patients, the patency of the iliac venous stent was assessed at CT performed during a follow-up period lasting 6-31 (mean, 18.9) months. All patients were assigned to the patent stent group (n=9) or the occluded stent group (n=5). In the former, the anatomic cause of patency included typical iliac vein compression (May-Thurner syndrome) (n=9), and a relatively short segmental thrombus occurring between the common iliac and the popliteal vein (n=8). Thrombi occurred in the iliac vein (n=3), between the common iliac and the femoral vein (n=3), and between the common iliac and the popliteal vein (n=2). In one case, a relatively long segmental thrombus occurred between the common iliac vein and the calf vein. In the occluded stent group, anatomic causes included atypical iliac vein compression (n=3) and a relatively long segmental thrombus between the common iliac and the calf vein (n=4). Typical iliac vein compression (May-Thurner syndrome) occurred in two cases, and a relatively short segmental thrombus between the external iliac and the common femoral vein in one. Factors which can affect the patency of an iliac venous stent positioned after catheter-directed thrombolysis are the anatomic cause of the stenosis, and the extent of a thrombus revealed at CT of acute DVT and occurring in a lower extremity prior to

  2. Late stent thrombosis: a not negligible issue after drug-eluting stent implantation

    Institute of Scientific and Technical Information of China (English)

    GAO Run-lin

    2007-01-01

    @@ Drug-eluting stent (DES) has markedly reduced restenosis and the need for target lesion revascularization (TLR). The safety profile of DES does not seem to differ from that of bare metal stent in the acute and subacute phases following coronary intervention.

  3. Acute and long-term outcome after Palmaz-Schatz stenting: analysis from the New Approaches to Coronary Intervention (NACI) registry.

    Science.gov (United States)

    Carrozza, J P; Schatz, R A; George, C J; Leon, M B; King, S B; Hirshfeld, J W; Curry, R C; Ivanhoe, R J; Buchbinder, M; Cleman, M W; Goldberg, S; Ricci, D; Popma, J J; Safian, R D; Baim, D S

    1997-11-20

    The randomized Stent Restenosis Study (STRESS) and Belgium Netherlands Stent (Benestent) trials established that elective use of Palmaz-Schatz stents (PSSs) in native coronary arteries with de novo lesions is associated with increased procedural success and reduced restenosis. However there are other clinical indications for which stents are commonly used (unplanned use, vein grafts, restenosis lesions) that are not addressed in these studies. From 1990-1992, 688 lesions in 628 patients were treated with PSSs in the New Approaches to Coronary Intervention (NACI) registry. Angiographic core laboratory readings were available for 543 patients (595 lesions, of which 106 were stented for unplanned indications, 239 were in saphenous vein bypass grafts, and 296 were previously treated). The cohort of patients in whom stents were placed for unplanned indications had more women, current smokers, and had a higher incidence of recent myocardial infarction (MI). Patients who underwent stenting of saphenous vein grafts were older, had a higher incidence of diabetes mellitus, unstable angina, prior MI, and congestive heart failure. Lesion success was similar in all cohorts (98%), but procedural success was significantly higher for planned stenting (96% vs 87%; p < 0.01). Predictors of adverse events in-hospital were presence of a significant left main stenosis and stenting for unplanned indication. The incidence of target lesion revascularization by 30 days was significantly higher for patients undergoing unplanned stenting due to a higher risk for stent thrombosis. Recent MI, stenting in native lesion, and small postprocedural minimum lumen diameter independently predicted target lesion revascularization at 30 days. Independent predictors of death, Q-wave myocardial infarction, or target lesion revascularization at 1 year included severe concomitant disease, high risk for surgery, left main disease, stenting in the left main coronary artery, and low postprocedure minimum lumen

  4. Will absorbable metal stent technology change our practice?

    Science.gov (United States)

    Bosiers, M; Deloose, K; Verbist, J; Peeters, P

    2006-08-01

    Peripheral stents aim to support revascularization procedures of intravascular stenoses by mechanically preventing vessel recoil and counteracting pathophysiologic processes of luminal re-narrowing triggered by procedural injury of the vessel wall. Despite improvements in stenting techniques and concomitant medication, repeated intervention due to target lesion re-stenosis is necessary on a significant percentage of patients. The permanent presence of an artificial implant plays a prominent role in the discussion of mechanisms causing in-stent restenosis. Permanent metallic implants pose the risk of a continuous interaction between non-absorbable stent and surrounding tissue, leading to physical irritation, long-term endothelial dysfunction, or chronic inflammatory reactions. In addition, there is a risk of stent fracture due to external mechanical forces. To overcome these shortcomings, technology of stenting has moved towards the development of temporary implants composed of biocompatible materials which mechanically support the vessel during the period of high risk for recoil and then completely degrade in the long-term perspective. This removes a potential trigger for late restenosis.

  5. Association between low serum magnesium level and major adverse cardiac events in patients treated with drug-eluting stents for acute myocardial infarction.

    Directory of Open Access Journals (Sweden)

    Guipeng An

    Full Text Available OBJECTIVES: We investigated the association of serum magnesium (Mg levels and major adverse cardiac events (MACEs after drug-eluting stent (DES implantation. BACKGROUND: Mg depletion plays a key role in the pathphysiologic features of diabetes mellitus, hypertension, thrombosis, arrhythmias and coronary artery disease. Whether the depletion is related to the long-term prognosis of DES implantation is not known. METHODS: From 2008 to 2011, we enrolled 414 consecutive patients <50 years old who underwent DES implantation for acute coronary syndrome. Serum Mg level was analyzed and patients were followed up for a median of 24 months (interquartile range 14-32 months for the occurrence of MACEs defined as death, myocardial infarction, stroke, and any revascularization. RESULTS: For patients with unstable angina, no significant association between serum Mg level and MACEs was found in the multivariate model. For patients with myocardial infarction, after adjusting for age, positive family history, smoking status, hypertension, hypercholesterolemia, and diabetes at baseline, the risk was 8.11-fold higher for patients with quartile 1 than 4 Mg level (95% confidence interval 1.7-38.75; P<0.01. In addition, when tested as a continuous variable, serum magnesium was a significant predictor for MACEs of acute myocardial infarction (HR [per 0.1 mM increase], 0.35 [95% CI, 0.19-0.63], p< 0.01, after adjustment for other confounders. CONCLUSIONS: Low serum level of Mg may be an important predictor of MACEs with DES implantation for acute myocardial infarction. Further research into the effectiveness of Mg supplementation for these patients is warranted.

  6. Comparing coronary stent material performance on a common geometric platform through simulated bench testing.

    Science.gov (United States)

    Grogan, J A; Leen, S B; McHugh, P E

    2012-08-01

    Absorbable metallic stents (AMSs) are a newly emerging cardiovascular technology which has the potential to eliminate long-term patient health risks associated with conventional permanent stents. AMSs developed to date have consisted of magnesium alloys or iron, materials with inferior mechanical properties to those used in permanent stents, such as stainless steel and cobalt-chromium alloys. However, for AMSs to be feasible for widespread clinical use it is important that their performance is comparable to modern permanent stents. To date, the performances of magnesium, iron, and permanent stent materials have not been compared on a common stent platform for a range of stent performance metrics, such as flexibility, radial strength, and recoil. In this study, this comparison is made through simulated bench testing, based on finite-element modelling. The significance of this study is that it allows potential limitations in current AMS performance to be identified, which will aid in focusing future AMS design. This study also allows the identification of limitations in current AMS materials, thereby informing the on-going development of candidate biodegradable alloys. The results indicate that the AMSs studied here can match the recoil characteristics and radial strength of modern permanent stents; however, to achieve this, larger strut dimensions are required. It is also predicted that the AMSs studied are inferior to permanent stents in terms of maximum absolute curvature and longitudinal stiffness.

  7. ANALYSIS OF OUTPATIENT PHYSICIANS, PRESCRIPTION OF DISAGGREGANT THERAPY FOR PATIENTS AFTER ACUTE MYOCARDIAL INFARCTION AND/OR CORONARY ANGIOPLASTY WITH STENT IMPLANTATION WITHIN THE RECVAD REGISTRY

    Directory of Open Access Journals (Sweden)

    A. V. Zagrebelnyi

    2015-01-01

    Full Text Available Objective: to estimate the quality of antiaggregants therapy in patients with coronary heart disease in outpatient settings. Materials and methods. The data of the retrospective outpatient RECVAD registry (3690 patients who lived in Ryazan and its Region and had evidence in their outpatient medical records for one of the diagnoses, such as coronary heart disease, hypertension, chronic heart failure, atrial fibrillation, or their concurrence, were used. Forty­nine patients after acute myocardial infarction (AMI and/or percutaneous coro­ nary interventions (PCI with stenting ≤ 1 year before their inclusion in the registry, who were to undergo dual antiaggregant therapy (DAT according to current clinical guidelines (CG, were identified among 427 patients after AMI and/or PCI with coronary angioplasty. Contra­ indications to DAT were simultaneously revealed and a relationship of the use of therapy to their presence was compared. Results. Among the 49 patients who had indications for DAT that was used in 15 (30.6 % cases and that was not in 3 (6.1 % patients in the presence of contraindications, 25 (51.0 % did not receive DAT in the absence of contraindications and 6 (12.3 % patients received the therapy in the presence of contraindications. Conclusion. DAT prescribed by outpatient physicians does not always meet the current CG. There are cases of not using DAT in the presence of obvious indications for DAT and, on the contrary, those of its use in the presence of contraindications. 

  8. Symptomatic stent cast.

    LENUS (Irish Health Repository)

    Keohane, John

    2012-02-03

    Biliary stent occlusion is a major complication of endoscopic stent insertion and results in repeat procedures. Various theories as to the etiology have been proposed, the most frequently studied is the attachment of gram negative bacteria within the stent. Several studies have shown prolongation of stent patency with antibiotic prophylaxis. We report the case of stent occlusion from a cast of a previously inserted straight biliary stent; a "stent cast" in an 86-year-old woman with obstructive jaundice. This was retrieved with the lithotrypter and she made an uneventful recovery. This is the first reported case of a biliary stent cast.

  9. Symptomatic stent cast.

    Science.gov (United States)

    Keohane, John; Moore, Michael; O'Mahony, Seamus; Crosbie, Orla

    2008-02-01

    Biliary stent occlusion is a major complication of endoscopic stent insertion and results in repeat procedures. Various theories as to the etiology have been proposed, the most frequently studied is the attachment of gram negative bacteria within the stent. Several studies have shown prolongation of stent patency with antibiotic prophylaxis. We report the case of stent occlusion from a cast of a previously inserted straight biliary stent; a "stent cast" in an 86-year-old woman with obstructive jaundice. This was retrieved with the lithotrypter and she made an uneventful recovery. This is the first reported case of a biliary stent cast.

  10. Usefulness of flexible covered stent in malignant colorectal obstruction

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Jee Hee; Kang, Sung Gwon; Kim, Hyung Jin; Noh, Hong Gi; Woo, Jae Hong; Suh, Chang Hae [Inha Univ. Hospital, Inchon (Korea, Republic of)

    1998-07-01

    To evaluate the usefulness of flexible covered stent in the treatment of acute colorectal obstruction secondary to colorectal carcinoma. Materials and Methods : Flexible covered stents were placed in 11 patients with clinical and radiologic signs of acute colonic obstruction secondary to colorectal carcinoma. The purposes of stent insertion were pre-operative bowel preparation in seven patients and palliative treatment in four. A fistula was present in two;in one this was between the proximal jejunum and colon, and the other was rectovaginal. The usefulness of stent insertion for the purpose of preoperative bowel preparation was evaluated according to the feasibility and status of bowel preparation, as decided by the operator. Palliative treatment for the relief of symptoms of acute bowel obstruction was evaluated according to the number and amount of defecation,bowel dilatation in simple abdomen radiography, and the presence of complications. Results : Bowel preparation for the purpose of preoperative bowel cleansing was easy in seven patients;the fecal materials remaining in the colon presented no problems during surgery. In one of four patients palliative treatment involved a colostomy;this was due to recurrent stent obstruction by fecal materials after three months, and in two other patients there was stent obstruction after two and five months, respectively. The stent in one of four patients who underwent palliative treatment was removed because of stent migration three days after insertion;the stents in two patients with fistulas covered the fistulas successfully. Complications after stent insertion were anal pain in three patients, anal bleeding in three and stent migration in one. Conclusion : The flexible covered stent was an effective device for the relief of acute colonic obstruction secondary to malignant rectosigmoid neoplasia. It allowed for single-stage operation and covered the fistula. We believe however that for further evaluation of the

  11. A comparative study of short- and medium-term outcomes comparing emergent surgery and stenting as a bridge to surgery in patients with acute malignant colonic obstruction.

    LENUS (Irish Health Repository)

    Kavanagh, Dara O

    2013-04-01

    The use of self-expanding metal stents as a bridge to surgery in the setting of malignant colorectal obstruction has been advocated as an acceptable alternative to emergency surgery. However, concerns about the safety of stenting have been raised following recent randomized studies.

  12. Assessment of the safety and performance of the STENTYS self-expanding coronary stent in acute myocardial infarction: Results from the APPOSITION I study

    NARCIS (Netherlands)

    G. Amoroso (Giovanni); R.J.M. van Geuns (Robert Jan); C.M. Spaulding (Christian); S. Manzo-Silberman (Stephane); K. Hauptmann (Karl); R. Spaargaren (René); H.M. Garcia-Garcia (Hector); P.W.J.C. Serruys (Patrick); S. Verheye (Stefan)

    2011-01-01

    textabstractAims: In the setting of ST-elevation myocardial infarction (STEMI), epicardial vasoconstriction and throm- bus load may lead to stent undersizing and malapposition after primary percutaneous coronary intervention (PPCI), which can both be responsible for stent thrombosis or restenosis. A

  13. A high maintenance dose of clopidogrel improves short-term clinical outcomes in patients with acute coronary syndrome undergoing drug-eluting stent implantation

    Institute of Scientific and Technical Information of China (English)

    HAN Ya-ling; WANG Bin; LI Yi; XU Kai; WANG Shou-li; JING Quan-min; WANG Zu-lu; WANG Dong-mei; MA Ying-yan; WANG Geng

    2009-01-01

    Background Recurrent ischemic events occurred even during routine use of 75 mg clopidogrel in addition to aspirin,that indicated a potentially insufficient maintenance dosage of clopidogrel.The aim of the present study was to evaluate the short-term efficacy and safety of a 150 mg maintenance dose of clopidogrel following a 600 mg loading dose in patients with an acute coronary syndrome (ACS) undergoing drug eluting stent (DES) implantation.Methods Between November 2005 and November 2006,a total of 813 consecutive ACS patients undergoing DES implantation were enrolled.A 600 mg loading dose was administered before percutaneous coronary intervention (PCI) nd patients were randomized to receive clopidogrel 75 mg or 150 mg for 30 days in addition to 300 mg aspidn daily.Primary end points were the composite of cardiac death,non-fatal myocardial infarction (MI) and urgent target vessel revascularization (UTVR).Secondary end points included stent thrombosis (ST),major and minor bleeding events at 30days.Results At a follow-up period of 30 days,4 (1.0%) patients in the 150 mg group and 9 (2.2%) patients in the 75 mg group (P >0.05) reached the primary end points.There was no significant difference in the incidences of MI (0.5% vs1.2%,P >0.05),UTVR (0.7% vs 2.0%,P >0.05),and cardiac death (0.2% vs 0.2%,P >0.05) between the two groups.The incidence of ST (0 vs 1.5%,P <0.05) was significantly lower in the 150 mg group than that in the 75 mg group.There were no significant differences between both groups regarding the risk of major (0.2% vs 0,P >0.05) or minor (0.5% vs 0.2%,P >0.05) bleedings.Conclusion A high clopidogrel maintenance dose of 150 mg daily following a 600 mg loading dose for the first month after PCI procedure reduces the risk of ST and appears to be safe in patients with ACS undergoing DES implantation.

  14. Comparison of a new stent and Wallstent for transjugular intrahepatic portosystemic shunt in a porcine model

    Institute of Scientific and Technical Information of China (English)

    Gao Jun Teng; Michael A. Bettmann; P. Jack Hoopes; Li Yang

    2001-01-01

    AIM To evaluate a new balloon-expandablestainless steel stent (Cordis stent ) in atransjugular intrahepatic portosystemic shunt(TIPS) porcine model and compared withWallstent.METHODS TIPS was performed in 26 normaldomestic pigs weighing 20 kg-30 kg using aCordis stent or Wallstent (13 pigs in each stent).All pigs were sacrificed at the 14th day afterTIPS. The stent deployment delivery system,stent patency, and stent recoil after placementwere evaluated. Proliferative response inrepresentative histological sections from thecenter, hepatic and portal regions of the twostent designs were quantified.RESULTS The shunt was widely patent in 4pigs in the Cordis stent group (4/12, prematuredead in 1 pig), and in 5 pigs in the Wallstentgroup (5/13). All remaining stents of bothdesigns were occluded or stenotic. The meanquantified proliferation including thickness ofthe proliferation and the ratio of proliferation:total area in three assayed regions in Cordisstent and Wallstent was 2.18 mm:2.00 mm, and59.18 mm2: 51.66 mm2, respectively (P >0.05).The delivery system and mechanical propertiesof the Cordis stent fuctioned well.CONCLUSION The new Cordis stent isappropriate for TIPS procedure.

  15. Computer Simulation of the Mechanical Behaviour of Implanted Biodegradable Stents in a Remodelling Artery

    Science.gov (United States)

    Boland, Enda L.; Grogan, James A.; Conway, Claire; McHugh, Peter E.

    2016-04-01

    Coronary stents have revolutionised the treatment of coronary artery disease. While coronary artery stenting is now relatively mature, significant scientific and technological challenges still remain. One of the most fertile technological growth areas is biodegradable stents; here, there is the possibility to generate stents that will break down in the body once the initial necessary scaffolding period is past (6-12 months) (Grogan et al. in Acta Biomater 7:3523, 2011) and when the artery has remodelled (including the formation of neo-intima). A stent angioplasty computational test-bed has been developed by the authors, based on the Abaqus software (DS-SIMULIA, USA), capable of simulating stent tracking, balloon expansion, recoil and in vivo loading in a atherosclerotic artery model. Additionally, a surface corrosion model to simulate uniform and pitting corrosion of biodegradable stents and a representation of the active response of the arterial tissue following stent implantation, i.e. neointimal remodelling, has been developed. The arterial neointimal remodelling simulations with biodegradable stent corrosion demonstrate that the development of new arterial tissue around the stent struts has a substantial effect on the mechanical behaviour of degrading stents.

  16. Drug-eluting stents in renal artery stenosis

    Energy Technology Data Exchange (ETDEWEB)

    Zaehringer, M. [Marienhospital Stuttgart, Department of Radiology, Stuttgart (Germany); Pattynama, P.M.T. [Erasmus MC-University Medical Center Rotterdam, Rotterdam (Netherlands); Talen, A. [genae associates nv, Antwerp (Belgium); Sapoval, M. [Hopital Europeen Georges Pompidou, Service de Radiologie Cardio-Vasculaire, Paris (France); Inserm U 780 epidemiologie Cardio Vasculaire, Paris (France)

    2008-04-15

    Because of higher acute and long-term success rates compared with balloon angioplasty alone, percutaneous stent implantation has become an accepted therapy for the treatment of atherosclerotic renal artery stenosis. Restenosis rates after successful renal stent placement vary from 6 up to 40%, depending on the definition of restenosis, the diameter of the treated vessel segment and comorbidities. The safety and efficacy of drug-eluting stents for the treatment of renal-artery stenosis is poorly defined. The recently published GREAT study is the only prospective study, comparing bare-metal and sirolimus-coated low profile stent systems in renal artery stenosis, showing a relative risk reduction of angiographic binary in-stent restenosis by 50%. This is an opinion paper on indications, current treatment options and restenosis rates following renal artery stenting and the potential use of drug-eluting stents for this indication. (orig.)

  17. A clinical evaluation of endoscopically placed self-expanding metallic stents in patients with acute large bowel obstruction

    DEFF Research Database (Denmark)

    Pommergaard, H C; Vilmann, Peter; Jakobsen, H L;

    2009-01-01

    in 71.4% of the benign cases with a mortality rate of 28,6%. CONCLUSIONS: Placement of SEMS for acute large bowel obstruction with malignant etiology is an effective and safe procedure with low mortality and morbidity. However results for benign obstructions are questionable and more research is needed...

  18. Safety and effectiveness of the Genous™ endothelial progenitor cell-capture stent in the first year following ST-elevation acute myocardial infarction: A single center experience and review of the literature

    Energy Technology Data Exchange (ETDEWEB)

    Pereira-da-Silva, Tiago, E-mail: tiagopsilva@sapo.pt; Bernardes, Luís; Cacela, Duarte; Fiarresga, António; Sousa, Lídia; Patrício, Lino; Ferreira, Rui Cruz

    2013-11-15

    Purpose: The Genous™ stent (GS) is designed to accelerate endothelization, which is potentially useful in the pro-thrombotic environment of ST-elevation acute myocardial infarction (STEMI). We aimed to evaluate the safety and effectiveness of the GS in the first year following primary percutaneous coronary intervention (PCI) and to compare our results with the few previously published studies. Methods and Materials: All patients admitted to a single center due to STEMI that underwent primary PCI using exclusively GS, between May 2006 and January 2012, were enrolled. The primary study endpoints were major adverse cardiac events (MACEs), defined as the composite of cardiac death, acute myocardial infarction and target vessel revascularization, at one and 12 months. Results: In the cohort of 109 patients (73.4% male, 59 ± 12 years), 24.8% were diabetic. PCI was performed in 116 lesions with angiographic success in 99.1%, using 148 GS with median diameter of 3.00 mm (2.50–4.00) and median length of 15 mm (9–33). Cumulative MACEs were 2.8% at one month and 6.4% at 12 months. Three stent thromboses (2.8%), all subacute, and one stent restenosis (0.9%) occurred. These accounted for the four target vessel revascularizations (3.7%). At 12 months, 33.9% of patients were not on dual antiplatelet therapy. Conclusions: GS was safe and effective in the first year following primary PCI in STEMI, with an apparently safer profile comparing with the previously published data. Summary: We report the safety and effectiveness of the Genous™ stent (GS) in the first year following primary percutaneous coronary intervention in ST-elevation acute myocardial infarction. A comprehensive review of the few studies that have been published on this subject was included and some suggest a less safe profile of the GS. Our results and the critical review included may add information and reinforce the safety and effectiveness of the GS in ST-elevation in acute myocardial infarction.

  19. Gas powered fluid gun with recoil mitigation

    Energy Technology Data Exchange (ETDEWEB)

    Grubelich, Mark C.; Yonas, Gerold

    2017-01-03

    A gas powered fluid gun for propelling a stream or slug of a fluid at high velocity toward a target. Recoil mitigation is provided by a cavitating venturi that reduces or eliminates the associated recoil forces, with minimal or no backwash. By launching a quantity of water in the opposite direction, net momentum forces are reduced or eliminated.

  20. Mechanism of nano silver stents in the treatment of acute cholangitis of severe type and the antibacterial property of nano silver stents%纳米银支架治疗重症胆管炎的机制及抗菌性研究

    Institute of Scientific and Technical Information of China (English)

    呼增吉; 贾长库; 韩霖; 符誉; 黄小龙

    2015-01-01

    目的:研究内镜下纳米银支架治疗急性重症胆管炎(ACST)的机制及纳米银支架的抗菌性。方法将20头猪随机分为纳米银支架组(n=8)、普通支架组(n=8)和对照组(n=4)。对照组采用内镜下逆行胆管造影(ERC),胆总管内注入大肠杆菌,乳头口用钛夹夹闭,封闭乳头。支架组在造模成功后行ERC+支架置入,支架末端在乳头口处以钛夹固定。观察术后猪的一般情况,分别于术前、术后1d、3d、5d采集猪血检测其白细胞计数、谷丙转氨酶(ALT)、碱性磷酸酶(ALP)、血清胆红素(TB)、血清肿瘤坏死因子(TNF-α)和白细胞介素-1(IL-1),观察猪死亡后的胆管病理改变。结果三组猪术前的各项观察指标比较差异均无统计学意义(P>0.05);术后对照组的白细胞及分类、ALT、ALP、TB、TNF-α和IL-1水平均逐步上升,且在各时点均明显高于两支架组,差异均有统计学意义(P<0.05);纳米银支架组和普通支架组在术后第五天白细胞计数及分类、血清TNF-α和IL-1比较差异均有统计学意义(P<0.05)。结论细菌感染和胆道梗阻是ACST的主要病因,内镜下置入支架治疗ACST,微创有效,纳米银支架有抗菌性。%Objective To study the mechanism of nano silver stents in the treatment of acute cholangitis of severe type (ACST) and the antibacterial property of nano silver stents under endoscope. Methods Twenty pigs were randomly divided into nano silver stent group (n=8), ordinary stent group (n=8) and control group (n=4). The control group was treated by endoscopic retrograde biliary imaging (ERC), followed by injecting E. coli through bile duct and enclosing papilla with titanium clips. The nano silver stent group and ordinary stent group were treated by ERC com-bined with stent implantation, followed by enclosing papilla with titanium clips. The peripheral blood samples were collected pre-operatively and at 1 day, 3 day, 5 day post

  1. Safety and efficacy of coronary stent implantation. Acute and six month outcomes of 1,126 consecutive patients treated in 1996 and 1997

    Directory of Open Access Journals (Sweden)

    Luiz Alberto Mattos

    1999-07-01

    Full Text Available PURPOSE: The authors analyzed the 30-day and 6-month outcomes of 1,126 consecutive patients who underwent coronary stent implantation in 1996 and 1997. METHODS: The 30-day results and 6-month angiographic follow-up were analyzed in patients treated with coronary stents in 1996 and 1997. All patients underwent coronary stenting with high-pressure implantation (>12 atm and antiplatelet drug regimen (aspirin plus ticlopidine. RESULTS: During the study period, 1,390 coronary stents were implanted in 1,200 vessels of 1,126 patients; 477 patients were treated in the year 1996 and 649 in 1997. The number of percutaneous procedures performed using stents increased significantly in 1997 compared to 1996 (64 % vs 48%, p=0.0001. The 30-day results were similar in both years; the success and stent thrombosis rates were equal (97% and 0.8%, respectively. The occurrence of new Q wave MI (1.3% vs 1.1%, 1996 vs 1997, p=NS, emergency coronary bypass surgery (1% vs 0.6%, 1996 vs 1997, p=NS and 30-day death rates (0.2% vs 0.5%, 1996 vs 1997, p=NS were similar. The 6-month restenosis rate was 25% in 1996 and 27% in 1997 (p= NS; the target vessel revascularization rate was 15% in 1996 and 16% in 1997 (p = NS. CONCLUSIONS: Intracoronary stenting showed a high success rate and a low incidence of 30-day occurrence of new major coronary events in both periods, despite the greater angiographic complexity of the patients treated with in 1997. These adverse variables did not have a negative influence at the 6-month clinical and angiographic follow-up, with similar rates of restenosis and ischemia-driven target lesion revascularization rates.

  2. Absence of gender disparity in short-term clinical outcomes in patients with acute ST-segment elevation myocardial infarction undergoing irolimus-eluting stent based primary coronary intervention: a report from Shanghai Acute Coronary Event (SACE) Registr

    Institute of Scientific and Technical Information of China (English)

    ZHANG Qi; LIAO Min-lei; HU Jian; SHEN Wei-feng; QIU Jian-ping; ZHANG Rui-yan; LI Yi-gang; HE Ben; JIN Hui-gen; ZHANG Jun-feng; WANG Xiao-long; JIANG Li

    2010-01-01

    Background Randomized, controlled trials have demonstrated the superiority of sirolimus-eluting stent (SES) implantation during primary percutaneous coronary intervention (PCI), as opposed to bare-metal stents, in patients with ST-elevation myocardial infarction (STEMI). This study aimed to test the hypothesis that clinical benefits of SES treatment were independent of gender in this setting.Methods A total of 2042 patients with STEMI undergoing SES-based primary PCI were prospectively enrolled into Shanghai Acute Coronary Event (SACE) registry (1574 men and 468 women). Baseline demographics, angiographic and PCI features, and in-hospital and 30-day major adverse cardiac events (MACE) were analyzed as a function of gender. Results Compared with men, women were older and more frequently had hypertension, diabetes, and hypercholesterolemia. Use of platelet glycoprotein IIb/IIIa receptor inhibitor (GPI, 65.5% vs. 62.2%, P=0.10) and procedural success rate (95.0% vs. 94.2%, P=0.52) were similar in both genders. In-hospital death and MACE occurred in 3.8% and 7.6%, and 4.5% and 8.1% in the male and female patients, respectively (all P >0.05). At 30-day follow-up, survival (94.3% vs. 93.8%, P=0.66) and MACE-free survival (90.2% vs. 89.3%, P=0.52) did not significantly differ between men and women. After adjustment for differences in patient demographics, angiographic and proceduralfeatures, there were no significant difference in either in-hospital (OR=0.77, 95%C/ of 0.48 to 1.22, P=0.30) or 30-day mortality (OR=1.28, 95%C/ of 0.73 to 2.23, P=0.38) between women and men.Conclusion Despite more advanced age and clustering of risk factors in women, female patients with STEMI treated by SES-based primary PCI had similar in-hospital and short-term clinical outcomes as their male counterparts.

  3. Gas powered fluid gun with recoil mitigation

    Science.gov (United States)

    Grubelich, Mark C; Yonas, Gerold

    2013-11-12

    A gas powered fluid gun for propelling a stream or slug of a fluid at high velocity toward a target. Recoil mitigation is provided that reduces or eliminates the associated recoil forces, with minimal or no backwash. By launching a quantity of water in the opposite direction, net momentum forces are reduced or eliminated. Examples of recoil mitigation devices include a cone for making a conical fluid sheet, a device forming multiple impinging streams of fluid, a cavitating venturi, one or more spinning vanes, or an annular tangential entry/exit.

  4. Gas powered fluid gun with recoil mitigation

    Science.gov (United States)

    Grubelich, Mark C.; Yonas, Gerold

    2016-03-01

    A gas powered fluid gun for propelling a stream or slug of a fluid at high velocity toward a target. Recoil mitigation is provided that reduces or eliminates the associated recoil forces, with minimal or no backwash. By launching a quantity of water in the opposite direction, net momentum forces are reduced or eliminated. Examples of recoil mitigation devices include a cone for making a conical fluid sheet, a device forming multiple impinging streams of fluid, a cavitating venturi, one or more spinning vanes, or an annular tangential entry/exit.

  5. [Ischaemic lesions of cerebral after carotid stenting].

    Science.gov (United States)

    Medvedev, R B; Tanashian, M M; Kuntsevich, G I; Lagoda, O V; Skrylev, S I; Krotenkova, M V; Koshcheev, A Iu; Suslin, A S; Gemdzhian, É G

    2015-01-01

    Carotid angioplasty with stenting is a reliable method of primary and secondary prevention of ischaemic stroke in patients with stenosing lesions of the internal carotid artery. However, carrying out such operations is sometimes associated with risk for the development of intraoperative impairments of cerebral circulation due to arterioarterial embolism in cerebral arteries, as well as vasospasm. Presented herein are the results of following up a total of 64 patients with pronounced atherosclerotic lesions of internal carotid arteries (>70%) - "symptomatic" and "asymptomatic", undergoing carotid stenting. Acute foci of ischaemia in the brain after stenting according to the findings of diffusion-weighted magnetic resonance tomography were revealed in 40% of cases, and in only 6% of patients they manifested themselves by symptoms of acute cerebral circulatory impairment. We revealed a direct correlation between the number, size of infarctions in the brain, and the appearance of neurological symptomatology. Intraoperative monitoring of blood flow in the middle cerebral artery during stenting makes it possible to predict the appearance of acute foci of cerebral ischaemia, to specify the genesis of perioperative stroke, as well as to evaluate clinical significance of vasospasm and material microembolism. The obtained findings should concentrate neurologists' attention on active postoperative follow up of patients subjected to carotid angioplasty with stenting in order to perform adequate personified neuroprotective correction, including preventive one.

  6. The qualitative assessment of biodegradable coronary stents with the use of intravascular ultrasound, optical coherence tomography and histology

    OpenAIRE

    Burcu GÜL

    2014-01-01

    Percutaneous coronary intervention (PCI) is the most common treatment for coronary artery disease (CAD). The first form of PCI introduced was balloon angioplasty. After that, the advent of coronary stents (tubular wire mesh for intravascular mechanical support) led to a new era in interventional cardiology. Through the implantation of bare metal stents (BMS), all three limitations of balloon angioplasty – coronary artery dissection, elastic recoil and negative remodelling – are prevented. Unf...

  7. Clinical experience in coronary stenting with the Vivant Z Stent.

    Science.gov (United States)

    Chee, K H; Siaw, F S; Chan, C G; Chong, W P; Imran, Z A; Haizal, H K; Azman, W; Tan, K H

    2005-06-01

    This single centre study was designed to demonstrate feasibility, safety and efficacy of the Vivant Z stent (PFM AG, Cologne, Germany). Patients with de novo lesion were recruited. Coronary angioplasty was performed with either direct stenting or after balloon predilatation. Repeated angiogram was performed 6 months later or earlier if clinically indicated. Between January to June 2003, a total of 50 patients were recruited (mean age 55.8 +/- 9 years). A total of 52 lesions were stented successfully. Mean reference diameter was 2.77 mm (+/-0.59 SD, range 2.05-4.39 mm) with mean target lesion stenosis of 65.5% (+/-11.6 SD, range 50.1-93.3%). Forty-six lesions (88.5%) were American College of Cardiologist/American Heart Association class B/C types. Direct stenting was performed in 18 (34.6%) lesions. Mean stent diameter was 3.18 mm (+/-0.41 SD, range 2.5-4 mm), and mean stent length was 14.86 mm (+/-2.72 SD, range 9-18 mm). The procedure was complicated in only one case which involved the loss of side branch with no clinical sequelae. All treated lesions achieved Thrombolysis In Myocardial Infarction 3 flow. Mean residual diameter stenosis was 12.2% (+/-7.55 SD, range 0-22.6%) with acute gain of 1.72 mm (+/-0.50 SD, range 0.5-2.8). At 6 months, there was no major adverse cardiovascular event. Repeated angiography after 6 months showed a restenosis rate of 17% (defined as >50% diameter restenosis). Mean late loss was 0.96 mm (+/-0.48 SD) with loss index of 0.61 (+/-0.38 SD). The restenosis rate of those lesions less than 3.0 mm in diameter was 22.2% compared with 6.25% in those lesions more than 3.0 mm in diameter. The Vivant Z stent was shown to be safe and efficacious with low restenosis rate in de novo coronary artery lesion.

  8. Emergency coronary stenting with the Palmaz-Schatz stent for failed transluminal coronary angioplasty: results of a learning phase.

    Science.gov (United States)

    Kiemeneij, F; Laarman, G J; van der Wieken, R; Suwarganda, J

    1993-07-01

    This study describes initial results of Palmaz-Schatz stent implantation in our department to restore and maintain vessel patency in 52 patients with obstructive dissection, defined as an intraluminal filling defect with coronary flow impairment after percutaneous transluminal coronary angioplasty (PTCA). The majority of patients (62%) underwent PTCA for unstable angina (n = 28), defined as angina at rest with documented ST segment changes resistant to nitrates, or acute myocardial infarction (n = 4). In six patients (11%) the stent could not be delivered. Seven of the remaining 46 patients (15%) had coronary artery bypass surgery performed because of increased risk for subacute stent occlusion, residual thrombosis, residual obstruction near the stent, coronary artery diameter less than 3.0 mm, or multiple and overlapping stents. One patient (3%) died in hospital from intracranial bleeding. Nine patients (23%) had subacute stent occlusion, retrospectively unpredictable in four patients. Nine of 29 patients (29%) with an uncomplicated clinical course after stenting had angiographic restenosis at a mean follow-up of 6.0 +/- 1.4 months (range 12 days to 8.3 months). Two patients (7%) died 3 months after successful stenting: one patient because of stent thrombosis after stopping warfarin before an abdominal operation and one patient after acute vascular surgery for late traumatic groin bleeding. Of the 39 medically treated patients with a stent, three (8%) had major bleeding complications. It is concluded that stent implantation is feasible in most patients with obstructive dissection after PTCA. After successful stent delivery, coronary flow is temporarily restored.(ABSTRACT TRUNCATED AT 250 WORDS)

  9. Factors Associated with the Use of Drug-Eluting Stents in Patients Presenting with Acute ST-Segment Elevation Myocardial Infarction

    Directory of Open Access Journals (Sweden)

    Jose F. Chavez

    2015-01-01

    Full Text Available Background. Drug-eluting stents (DES have proven clinical superiority to bare-metal stents (BMS for the treatment of patients with ST-segment elevation myocardial infarction (STEMI. Decision to implant BMS or DES is dependent on the patient’s ability to take dual antiplatelet therapy. This study investigated factors associated with DES placement in STEMI patients. Methods. Retrospective analysis was performed on 193 patients who presented with STEMI and were treated with percutaneous coronary intervention at an urban, tertiary care hospital. Independent factors associated with choice of stent type were determined using stepwise multivariate logistic regression. Odds ratio (OR was used to evaluate factors significantly associated with DES and BMS. Results. 128 received at least one DES, while 65 received BMS. BMS use was more likely in the setting of illicit drug or alcohol abuse ([OR] 0.15, 95% CI 0.05–0.48, p≤0.01, cardiogenic shock (OR 0.26, 95% CI 0.10–0.73, p=0.01, and larger stent diameter (OR 0.28, 95% CI 0.11–0.68, p≤0.01. Conclusions. In this analysis, BMS implantation was associated with illicit drug or alcohol abuse and presence of cardiogenic shock. This study did not confirm previous observations that non-White race, insurance, or income predicts BMS use.

  10. Stenting plus coiling: dangerous or helpful?; Stenting plus Coiling bei akut rupturierten intrakraniellen Aneurysmen

    Energy Technology Data Exchange (ETDEWEB)

    Wanke, I.; Gizewski, E.; Doerfler, A.; Stolke, D.; Forsting, M. [Essen Univ. (Germany). Inst. fuer Radiologie und Neuroradiologie

    2005-09-01

    Purpose: the purpose of this study was to evaluate the procedural risk of treating acute ruptured aneurysms with a stentcoil combination. Material and methods: between August 2001 and January 2004 we treated nine acute subarachnoid hemorrhage (SAH) patients with a combination of stents and platinum coils. Results: six aneurysms were 100% eliminated; the residual three aneurysms had a 95% to 99% occlusion. A transient thrombosis in the stent in one patient could be recanalized by intravenous application of ReoPro {sup registered}. In another patient an occlusive vasospasm at the distal end of the stent was successfully treated with intraarterial Nimotop {sup registered}. Neurological complications occurred in none of the patients. Conclusion: in broad-based aneurysms which cannot be clipped or in which any neurosurgical treatment presents an unacceptably high risk (posterior circulation and paraophthalmic aneurysms), treatment using a combination of stent and platinum coils might be an option even in the acute phase of an SAH. Platelet aggregation can be treated with Aspirin registered and Plavix {sup registered} after placement of the first coil, vasospasms with intraarterial Nimotop {sup registered}, and acute stent thrombosis with GP IIa/IIIb-antagonists. (orig.)

  11. SMART Control stents in femoropopliteal region

    Directory of Open Access Journals (Sweden)

    Jagić Nikola

    2008-01-01

    Full Text Available Introduction/Aim. Occlusive disease of lower limb arteries have been so far traditionally best treated with bypass surgery, but we want to find minimally invasive approach that should be at least as good as conventional surgery, and hopefully better. The aim of this study was to evaluate SMART Control stents (Cordis, J&J in Trans Atlantic Society Consensus (TASC B and C femoropopliteal lesions during one-year follow-up. Methods. Retrospective nonrandomized analysis included forty arteries in consecutive 40 patients who were stented with SMART Control stents. Primary patency at 12-month verified with Duplex Ultrasound and Acute Brachial Index (ABI as well as freedom from Target Vessel Revascularization (TVR were primary endpoints. Results. Primary technical success at stent implantation was 100%. Mean ABI values were preprocedurally 0.50, postprocedurally 0.83, at one month 0.86, at six months 0.84, at one year 0.78. After one year 39 stents were patent (97.5%. Conclusion. Excellent performance of the stent from technical point of view and a midterm results in vessel patency, as well as the absence of need for TVR were achieved. Yet, life expectancy in this cohort group of patients demands longer follow up data to draw a definite sustained positive conclusion.

  12. Measurement of scintillation efficiency for nuclear recoils in liquid argon

    CERN Document Server

    Gastler, D; Hime, A; Stonehill, L C; Seibert, S; Klein, J; Lippincott, W H; McKinsey, D N; Nikkel, J A

    2010-01-01

    The scintillation light yield of liquid argon from nuclear recoils relative to electronic recoils has been measured as a function of recoil energy from 10 keVr up to 250 keVr. The scintillation efficiency, defined as the ratio of the nuclear recoil scintillation response to the electronic recoil response, is 0.25 \\pm 0.02 + 0.01(correlated) above 20 keVr.

  13. Circadian Variation in Coronary Stent Thrombosis

    NARCIS (Netherlands)

    Mahmoud, Karim D.; Lennon, Ryan J.; Ting, Henry H.; Rihal, Charanjit S.; Holmes, David R.

    2011-01-01

    Objectives We sought to determine the circadian, weekly, and seasonal variation of coronary stent thrombosis. Background Other adverse cardiovascular events such as acute myocardial infarction are known to have higher incidences during the early morning hours, Mondays, and winter months. Methods The

  14. Neoatherosclerosis in the stent

    Directory of Open Access Journals (Sweden)

    A. A. Komkov

    2015-01-01

    Full Text Available Achievements of interventional cardiology in the treatment of coronary artery disease are based on coronary balloon angioplasty with implanting bare metal stents and drug eluting stents. Questions of complications such as early stent thrombosis and restenosis of stent were solved in a considerable degree. However, with the lengthening of the followup period, the problem of late complications became obvious. Except endothelization and fibromuscular proliferation in stented coronary arteries the process of plaque formation has an important influence on later complications in follow-up period more than one year. This process was defined as neoatherosclerosis. This is verified by clinical manifestations of the disease, histological studies, angioscopy, intravascular ultrasound and optical-coherence tomography in stented patients. Dynamic observation of the condition in stentedcoronary arteries showed multistep proliferation with restenosis, its regression, and neoatherosclerosis development. Evidences of neoatherosclerosis formation in stented coronary arteries are considered in this review.

  15. The interventional thrombolysis and stenting of acute internal carotid occlusion%颈内动脉急性闭塞的溶栓及支架置入治疗

    Institute of Scientific and Technical Information of China (English)

    廖凯兵; 祝望才; 郑传胜

    2014-01-01

    Objective:To investigate the efficacy and safety of the interventional thrombolysis and stenting in patients with acute internal carotid occlusion.Methods:Intra-arterial thrombolysis was carried out and followed by stent implantation for the residual vascular stenosis in 6 patients with acute internal carotid occlusion.The neurological impairment score be-fore the treatment and at 24 hours after the treatment were evaluated.The incidence of complications and the changes in limbs activity and consciousness were observed.Results:6 patients got arterial recanalization and the blood flow recovered. The clinical symptoms were improved rapidly.At 24 hours after the treatment,the muscle strength increased by 3 grades in 4 patients and 2 grades in 2 patients.Conclusion:The efficacy of the interventional thrombolysis and stenting in acute inter-nal carotid occlusion is positive.It is more effective and safer when the treatment is given earlier.%目的:探讨颈内动脉急性闭塞的溶栓及支架置入治疗的有效性及安全性。方法:对6例颈内动脉急性闭塞的患者行动脉内溶栓治疗,其后对残余狭窄行支架置入治疗。溶栓前及治疗后24 h 进行神经功能缺损评分,同时观察脑内及其他系统有无出血并发症,并观察肢体活动及意识改善情况。结果:6例患者颈内动脉完全再通,血流量恢复,临床症状改善迅速,24h后4例瘫痪肢体肌力提高3级,2例提高2级。结论:颈内动脉急性闭塞患者的溶栓及支架置入治疗的疗效是值得肯定的。治疗时间越早疗效越好,安全性越高。

  16. Firebird sirolimus eluting stent versus bare mental stent in patients with ST-segment elevation myocardial infarction

    Institute of Scientific and Technical Information of China (English)

    GAO Hai; YAN Hong-bing; ZHU Xiao-ling; LI Nan; AI Hui; WANG Jian; LI Shi-ying; YANG Duo

    2007-01-01

    Background There are few evidences about the value of drug eluting stent in patients with ST-segment elevation myocardial infarction (STEMI). We prospectively designed a randomized controlled trial to compare the safety and efficacy of Firebird sirolimus eluting stent (Firebird stent) and bare metal stent (BMS).Methods Patients with STEMI enrolled during one year period were randomized to undergo implantation of Firebird stent or BMS, and clinical and angiographic follow-up. The primary endpoint of the present study was in-lesion late lumen loss (LLL) at 6 months, and secondary endpoint includes stent thrombosis and major adverse cardiac events (MACE) at 6 months.Results During one year period, 156 patients were randomized into the Firebird stent group (101 patients with an average age of 57.8 years) or the BMS group (55 patients with 59.7 years on average). Six-month angiographic follow-up was available in 66.3% and 63.7% of patients assigned to Firebird stent and BMS, respectively. At 6-month follow-up,mortality, target vessel revascularization (TVR) and MACE were 2.0%, 6.9% and 9.9% in the Firebird stent group, while 3.6%, 30.9% and 36.4% in the BMS group (P<0.05). Subacute thrombosis occurred in 1 patient in both groups,respectively. The mean LLL was 0.18 mm in the Firebird stent group versus 0.72 mm in the BMS group.Conclusion Implantation of Firebird sirolimus eluting stent for STEMI may greatly reduce TVR and MACE at 6 months with low incidence of acute/subacute stent thrombosis compared with BMS.

  17. Association between Low Serum Magnesium Level and Major Adverse Cardiac Events in Patients Treated with Drug-Eluting Stents for Acute Myocardial Infarction

    OpenAIRE

    Guipeng An; Zhongqi Du; Xiao Meng; Tao Guo; Rui Shang; Jifu Li; Fengshuang An; Wenjing Li; Cheng Zhang

    2014-01-01

    OBJECTIVES: We investigated the association of serum magnesium (Mg) levels and major adverse cardiac events (MACEs) after drug-eluting stent (DES) implantation. BACKGROUND: Mg depletion plays a key role in the pathphysiologic features of diabetes mellitus, hypertension, thrombosis, arrhythmias and coronary artery disease. Whether the depletion is related to the long-term prognosis of DES implantation is not known. METHODS: From 2008 to 2011, we enrolled 414 consecutive patients

  18. Expandable bioresorbable endovascular stent. I. Fabrication and properties.

    Science.gov (United States)

    Su, Shih-Horng; Chao, Robert Y N; Landau, Charles L; Nelson, Kevin D; Timmons, Richard B; Meidell, Robert S; Eberhart, Robert C

    2003-06-01

    A bioresorbable, expandable poly(L-lactic acid) stent has been designed, based on a linear, continuous coil array principle, by which multiple furled lobes convert to a single lobe upon balloon expansion, without heating. Stent strength and compliance are sufficient to permit deployment by a conventional balloon angioplasty catheter. Several multiple lobe configurations were investigated, with expansion ratios ranging from 1.4 to 1.9 and expanded diameters ranging from 2.3 to 4.7 mm. Compression resistance of the expanded stent is dependent on fiber coil density and fiber ply. A range sufficient for endovascular service was obtained, with less than 4% elastic recoil in six day saline incubation studies. Surface plasma treatment with di(ethylene glycol) vinyl ether significantly reduced platelet adhesion in a 1 h porcine arteriovenous shunt model. Patency was maintained in one week implant studies in the porcine common femoral artery. However, a strong inflammatory response, and significant reduction of the vascular lumen were observed following two weeks implantation. The design principles and fabrication techniques for this bioresorbable stent are sufficiently versatile that a broad range of applications can be addressed. Much work remains to be done, including long-term evaluation of the inflammatory response, and of polymer degradation. The results of this study demonstrate the feasibility of expandable biodegradable stent design and deployment by conventional means.

  19. The Development of Coronary Artery Stents: From Bare-Metal to Bio-Resorbable Types

    Directory of Open Access Journals (Sweden)

    Ming-Yun Ho

    2016-07-01

    Full Text Available Coronary artery disease is the leading cause of death worldwide. Conventional balloon angioplasty is associated with high rates of complications such as coronary dissection and vessel recoil. The deployment of bare-metal stents (BMSs can overcome these problems and achieve a better patency rate than simple balloon angioplasty. It has been shown that the stent design including structure platform, size, length, and strut thickness has a major influence on the clinical results. Even though angioplasty with BMS implantation is widely used in coronary interventions, the restenosis rate due to neointimal hyperplasia remains high. Therefore, drug-eluting stents (DESs coated with anti-proliferative agents and polymers have been developed to reduce the restenosis rate and improve the clinical outcomes. Although the repeat revascularization rate of DESs is lower than that of BMSs, the long-term stent thrombosis rate is higher than for BMSs. Therefore, new and emerging generations of stents, in which, for example, thinner struts and bioresorbable polymers are used, are available for clinical use. However, there are only a limited number of clinical trials, in which these newer stents have been compared with BMSs and first- and second-generation DESs. The purpose of this review was to provide up-to-date information on the evolution of coronary artery stents from BMSs to DESs to bioresorbable stents (BRSs.

  20. Recoil Effects in Microwave Ramsey Spectroscopy

    CERN Document Server

    Wolf, P; Wolf, Peter; Borde, Christian J.

    2004-01-01

    We present a theory of recoil effects in two zone Ramsey spectroscopy, particularly adapted to microwave frequency standards using laser cooled atoms. We describe the atoms by a statistical distribution of Gaussian wave packets which enables us to derive and quantify effects that are related to the coherence properties of the atomic source and that have not been considered previously. We show that, depending on the experimental conditions, the expected recoil frequency shift can be partially cancelled by these effects which can be significant at microwave wavelengths whilst negligible at optical ones. We derive analytical expressions for the observed interference signal in the weak field approximation, and numerical results for realistic caesium fountain parameters. In the near future Cs and Rb fountain clocks are expected to reach uncertainties which are of the same order of magnitude (10^{-16}) as first estimates of the recoil shift at microwave frequencies. We show, however, that the partial cancellation p...

  1. Auxetic coronary stent endoprosthesis

    DEFF Research Database (Denmark)

    Amin, Faisal; Ali, Murtaza Najabat; Ansari, Umar;

    2014-01-01

    BACKGROUND: Cardiovascular heart disease is one of the leading health issues in the present era and requires considerable health care resources to prevent it. The present study was focused on the development of a new coronary stent based on novel auxetic geometry which enables the stent to exhibit...... a negative Poisson's ratio. Commercially available coronary stents have isotropic properties, whereas the vascular system of the body shows anisotropic characteristics. This results in a mismatch between anisotropic-isotropic properties of the stent and arterial wall, and this in turn is not favorable...... for mechanical adhesion of the commercially available coronary stents with the arterial wall. It is believed that an auxetic coronary stent with inherent anisotropic mechanical properties and negative Poisson's ratio will have good mechanical adhesion with the arterial wall. METHODS: The auxetic design...

  2. Impacted calculus within a urethral stent: A rare cause of urinary retention

    Directory of Open Access Journals (Sweden)

    Shanmugasundaram Rajaian

    2011-01-01

    Full Text Available An elderly male presented to the emergency department with acute urinary retention. He had poor flow of urine associated with serosanguinous discharge per urethra for 3 days duration. Earlier he underwent permanent metallic urethral stenting for post TURP bulbar urethral stricture. Plain X-ray of Pelvis showed an impacted calculus within the urethral stent in bulbar urethra. Urethrolitholapaxy was done with semirigid ureteroscope. Urethral stent was patent and well covered. Subsequently he had an uneventful recovery. We describe a unique case of acute urinary retention due to calculus impaction within a urethral stent.

  3. 支架象鼻手术治疗急性Stanford B型主动脉夹层%Stented elephant trunk in surgical approach for acute Standford type B aortic dissection in 146 cases

    Institute of Scientific and Technical Information of China (English)

    邓宏平; 王志维; 夏军; 徐鹏; 胡小平; 周桢; 任宗力

    2012-01-01

    Objective To review the experience of stented elephant trunk( SET )procedure under deep hypothermic cardiopulmonary bypass for acute Stanford type B aortic dissection. Methods From January 2003 to January 2011,146 consecutive patients with acute Standford type B aortic dissection received transaortic stented graft implantation into the descending aorta under deep hypothermia circulatory arrest. The in - hospital mortality rate and complication rate between Standford type A and Standford type B were analysed. Results Average cardiopulmonary bypass time was( 155 ±30 )min, average - cross clamp time was( 32 ± 3 )min, and average deep hypothermia circulatory arrest time was( 20 ± 3 )min. The in - hospital mortality was 2. 05% ( 3/146 ). A total of 138 patients were followed up for 4 ~ 98 months ( mean,57. 3 months ),and the 1 - year survival rate was 97. 16%. One patient died from massive bowel necrosis after 11 months. There was no paraplegia or reoperation. The complication rate of acute Standford type B aortic dissection was 14.4% and that of Standford type A aortic dissection was 35. 3% ,respectively. The difference was statistically significant. Conclusion SET implantation under deep hypothermic cardiopulmonary bypass is a simple,safe and effective method for acute Stanford type B aortic dissection.%目的 总结深低温停循环下支架象鼻手术治疗急性Stanford B型主动脉夹层的临床经验.方法 对146例急性Stanford B 型主动脉夹层患者行支架象鼻手术.结果 平均体外循环时间(155±30)min,平均心肌阻断时间(32±3)min,停循环时间(20±3)min.住院死亡3例(2.05 %,3/146),术后脑栓塞及脑出血各1例.随访138例,随访时间4~98个月,平均57.3个月,1年生存率为97.16%(137/141),1例11个月后死于广泛性肠坏死.无截瘫及再次手术者.结论 支架象鼻植入术治疗急性Stanford B 型主动脉夹层简单、安全、有效.

  4. Titanium-nitride-oxide-coated coronary stents: insights from the available evidence.

    Science.gov (United States)

    Karjalainen, Pasi P; Nammas, Wail

    2016-11-12

    Coating of stent surface with a biocompatible material is suggested to improve stent safety profile. A proprietary process was developed to coat titanium-nitride-oxide on the stent surface, based on plasma technology that uses the nano-synthesis of gas and metal. Preclinical in vitro and in vivo investigation confirmed blood compatibility of titanium (nitride-) oxide films. Titanium-nitride-oxide-coated stents demonstrated a better angiographic outcome, compared with bare-metal stents at mid-term follow-up; however, they failed to achieve non-inferiority for angiographic outcome versus second-generation drug-eluting stents. Observational studies showed adequate clinical outcome at mid-term follow-up. Non-randomized studies showed an outcome of titanium-nitride-oxide-coated stents comparable to - or better than - first-generation drug-eluting stents at long-term follow-up. Two randomized controlled trials demonstrated comparable efficacy outcome, and a better safety outcome of titanium-nitride-oxide-coated stents versus drug-eluting stents at long-term follow-up. Evaluation by optical coherence tomography at mid-term follow-up revealed better neointimal strut coverage associated with titanium-nitride-oxide-coated stents versus drug-eluting stents; yet, neointimal hyperplasia thickness was greater. Key messages Stents coated with titanium-nitride-oxide demonstrated biocompatibility in preclinical studies: they inhibit platelet and fibrin deposition, and reduce neointimal growth. In observational and non-randomized studies, titanium-nitride-oxide-coated stents were associated with adequate safety and efficacy outcome. In randomized trials of patients with acute coronary syndrome, titanium-nitride-oxide-coated stents were associated with a better safety outcome, compared with drug-eluting stents; efficacy outcome was comparable.

  5. Vessel healings after stenting with different polymers in STEMI patients

    Science.gov (United States)

    Jin, Qin-Hua; Chen, Yun-Dai; Tian, Feng; Guo, Jun; Jing, Jing; Sun, Zhi-Jun

    2016-01-01

    Background Different stents implantation in ST-segment elevation myocardial infarction (STEMI) patients may influence the long term prognosis by affecting vessel healings after stenting. The aim of this study was to evaluate the vessel healings after implantation of drug eluting stents (DES) with biodegradable or durable polymer or of bare-metal stents (BMS) in patients with acute STEMI. Methods This study included 50 patients, who underwent follow up angiogram and optical coherence tomography (OCT) assessment about one year after percutaneous coronary intervention (PCI) for STEMI. According to the initial stents types, these patients were classified to durable (n = 19) or biodegradable polymer sirolimus-eluting stents (n = 15), or BMS (n = 16) groups. The conditions of stent struts coverage and malapposition were analyzed with OCT technique. Results A total of 9003 struts were analyzed: 3299, 3202 and 2502 from durable or biodegradable polymer DES, or BMS, respectively. Strut coverage rate (89.0%, 94.9% and 99.3%, respectively), malapposition presence (1.7%, 0.03% and 0 of struts, respectively) and average intimal thickness over struts (76 ± 12 µm, 161 ± 30 µm and 292 ± 29 µm, respectively) were significantly different among different stent groups (all P < 0.001). Conclusions Vessel healing status in STEMI patients is superior after implantation of biodegradable polymer DES than durable polymer DES, while both are inferior to BMS. PMID:27403139

  6. Drug-eluting stents and bare metal stents in patients with NSTE-ACS

    DEFF Research Database (Denmark)

    Pedersen, Sune Haahr; Pfisterer, Matthias; Kaiser, Christoph;

    2014-01-01

    Aims: The use of drug-eluting stents (DES) in patients with non-ST-segment elevation acute coronary syndrome (NSTE-ACS) is controversial and not yet endorsed in clinical guidelines. Methods and results: This was an a priori planned post hoc analysis involving 754 NSTE-ACS patients from the random...

  7. Proton recoils in organic liquid scintillator

    Energy Technology Data Exchange (ETDEWEB)

    Winter, Juergen [Technische Universitaet Muenchen, Physik Department E15, Garching (Germany); Collaboration: LENA Working Group

    2012-07-01

    In liquid-scintillator detectors like the LENA (Low Energy Neutrino Astronomy) project, understanding the nature of proton recoils is vital. First of all concerning the observation of the diffuse Supernova anti {nu}{sub e} background with the inverse beta decay (IBD). This signature can be mimicked by the thermalization and capture of a knockout neutron originating from inelastic NC interactions of atmospheric neutrinos on {sup 12}C. However, with the help of pulse shape discrimination between the neutron-induced proton recoils and the prompt positron signal from the IBD, this background might be reduced effectively. Furthermore, elastic {nu}-p scattering is an important channel for neutrinos from a galactic core-collapse SN. In order to reconstruct the initial neutrino energy, the energy-dependent quenching factor of proton recoils has to be known. Therefore, a neutron scattering experiment at the Maier-Leibnitz-Laboratorium in Garching has been set up in order to understand the response of proton recoils in organic liquid scintillator.

  8. QED theory of the nuclear recoil effect in atoms

    CERN Document Server

    Shabaev, V M

    1998-01-01

    The quantum electrodynamic theory of the nuclear recoil effect in atoms to all orders in \\alpha Z is formulated. The nuclear recoil corrections for atoms with one and two electrons over closed shells are considered in detail. The problem of the composite nuclear structure in the theory of the nuclear recoil effect is discussed.

  9. Optical recoil of asymmetric nano-optical antenna.

    Science.gov (United States)

    Song, Jung-Hwan; Shin, Jonghwa; Lim, Hee-Jin; Lee, Yong-Hee

    2011-08-01

    We propose nano-optical antennas with asymmetric radiation patterns as light-driven mechanical recoil force generators. Directional antennas are found to generate recoil force efficiently when driven in the spectral proximity of their resonances. It is also shown that the recoil force is equivalent to the Poynting vector integrated over a closed sphere containing the antenna structures.

  10. Primary intracoronary stenting in 39 patients with acute myocardial infarction%冠状动脉支架植入术治疗急性心肌梗塞39例

    Institute of Scientific and Technical Information of China (English)

    颜红兵; 马长生; 王勇; 周玉杰; 李宪伦; 郑知刚; 柯元南

    2001-01-01

    目的:小结采用直接冠状动脉支架植入术治疗39例急性心肌梗塞患者的中期效果。方法:接受介入治疗距胸痛发作的平均时间为4.2 h。经股动脉采用Judkins技术完成冠状动脉造影及支架植入术。在38例患者42支血管共植入55个支架,1例患者仅行右冠状动脉球囊成形术。结果:术后即刻TIMI血流3级者36例(92.3%),TIMI血流2级者3例(7.7%)。术中6例(15.4%)在梗塞相关动脉开通后出现心室颤动,1例(2.6%)死于继发性心室颤动。术后平均随访8.1个月,除1例死于术后2周非梗塞相关动脉择期支架植入术外,无心肌梗塞、做外科冠状动脉搭桥术和再次做梗塞相关动脉介入治疗的病例。结论:直接冠状动脉支架术可以迅速获得梗塞相关动脉TIMI 3级血流,中期效果良好。%Objective:To describe the mid-term result of primary intracoronary stenting in 39 patients with acute myocardial infarction.Methods:Coronary stenting was applied within an average 4.2 hours after onset of chest pain by using Judkins technique via femoral artery.Fifty-five stents were implanted into 42 infarct related coronary arteries with a full procedural success rate.Results:Thrombolysis in myocardial infarction(TIMI)grade 3 flow was archived in 36 patients (92.3%), and TIMI grade 2 flow in three patients (7.7%).In the procedure, reperfusional arrhythmia-ventricle fibrillation occurred in six patients (15.4%) while a patent infarct-related artery was established,and another patient (2.6%) died of secondary ventricle fibrillation.Except one patient who died of acute coronary thrombosis secondary to elective coronary angioplasty for another non-infarct related artery after two weeks,no myocardial infarction, coronary artery bypass grafting or repeat percutaneous transluminal coronary angioplasty of the infarct-related vessel occurred during an average 8.1 months clinical follow-up.Conclusion:Primary coronary stenting

  11. Treatment of splenic artery aneurysm with double overlapping bare stents: case report

    Energy Technology Data Exchange (ETDEWEB)

    Kwak, Hyo Sung; Han, Young Min; Jin, Gong Yong [School of Medicine, Chonbuk National Univ., Chonju (Korea, Republic of)

    2004-09-01

    The traditional treatment of splenic artery aneurysm (SAA) is generally surgery and/or transcatheter arterial embolization, but recently, the treatment of SAA using a stent graft has been reported. However, the acute angle of the celiac axis, as well as the tortuous path of the splenic artery makes the use of stent graft difficult for treatment of aneurysma. We report here a case of SAA treated with the technique of double overlapping metallic stents.

  12. Everolimus-eluting coronary stents

    Directory of Open Access Journals (Sweden)

    Alejandro Saez

    2010-09-01

    Full Text Available Alejandro Saez, Raul MorenoDivision of Interventional Cardiology, University Hospital La Paz, Madrid, SpainAbstract: Bare metal stents enabled a reduction in the risk of early procedural complications and restenosis in comparison with balloon angioplasty alone, but introduced a new and device-specific iatrogenic condition, ie, in-stent restenosis due to increased neointimal hyperplasia. Sirolimus- and paclitaxel-eluting stents reduce restenosis and the need for new revascularizations in comparison with bare metal stents, although at the cost of a slight increase in the risk of late stent thrombosis and a need for prolonged dual antiplatelet therapy. Everolimus is an analog of sirolimus with an increased solubility. In this review, the currently available evidence for everolimus-eluting stents is revised, including randomized trials against bare metal stents, and head-to-head trials comparing this stent with other drug-eluting stents.Keywords: coronary stents, restenosis, everolimus, review

  13. Ionization and scintillation of nuclear recoils in gaseous xenon

    Energy Technology Data Exchange (ETDEWEB)

    Renner, J., E-mail: jrenner@lbl.gov [Lawrence Berkeley National Laboratory (LBNL), 1 Cyclotron Road, Berkeley, CA 94720 (United States); Department of Physics, University of California, Berkeley, CA 94720 (United States); Gehman, V.M.; Goldschmidt, A.; Matis, H.S.; Miller, T.; Nakajima, Y.; Nygren, D.; Oliveira, C.A.B.; Shuman, D. [Lawrence Berkeley National Laboratory (LBNL), 1 Cyclotron Road, Berkeley, CA 94720 (United States); Álvarez, V. [Instituto de Física Corpuscular (IFIC), CSIC & Universitat de València, Calle Catedrático José Beltrán, 2, 46980 Paterna, Valencia (Spain); Borges, F.I.G. [Departamento de Fisica, Universidade de Coimbra, Rua Larga, 3004-516 Coimbra (Portugal); Cárcel, S. [Instituto de Física Corpuscular (IFIC), CSIC & Universitat de València, Calle Catedrático José Beltrán, 2, 46980 Paterna, Valencia (Spain); Castel, J.; Cebrián, S. [Laboratorio de Física Nuclear y Astropartículas, Universidad de Zaragoza, Calle Pedro Cerbuna 12, 50009 Zaragoza (Spain); Cervera, A. [Instituto de Física Corpuscular (IFIC), CSIC & Universitat de València, Calle Catedrático José Beltrán, 2, 46980 Paterna, Valencia (Spain); Conde, C.A.N. [Departamento de Fisica, Universidade de Coimbra, Rua Larga, 3004-516 Coimbra (Portugal); and others

    2015-09-01

    Ionization and scintillation produced by nuclear recoils in gaseous xenon at approximately 14 bar have been simultaneously observed in an electroluminescent time projection chamber. Neutrons from radioisotope α-Be neutron sources were used to induce xenon nuclear recoils, and the observed recoil spectra were compared to a detailed Monte Carlo employing estimated ionization and scintillation yields for nuclear recoils. The ability to discriminate between electronic and nuclear recoils using the ratio of ionization to primary scintillation is demonstrated. These results encourage further investigation on the use of xenon in the gas phase as a detector medium in dark matter direct detection experiments.

  14. Ionization and scintillation of nuclear recoils in gaseous xenon

    CERN Document Server

    Renner, J; Goldschmidt, A; Matis, H S; Miller, T; Nakajima, Y; Nygren, D; Oliveira, C A B; Shuman, D; Álvarez, V; Borges, F I G; Cárcel, S; Castel, J; Cebrián, S; Cervera, A; Conde, C A N; Dafni, T; Dias, T H V T; Díaz, J; Esteve, R; Evtoukhovitch, P; Fernandes, L M P; Ferrario, P; Ferreira, A L; Freitas, E D C; Gil, A; Gómez, H; Gómez-Cadenas, J J; González-Díaz, D; Gutiérrez, R M; Hauptman, J; Morata, J A Hernando; Herrera, D C; Iguaz, F J; Irastorza, I G; Jinete, M A; Labarga, L; Laing, A; Liubarsky, I; Lopes, J A M; Lorca, D; Losada, M; Luzón, G; Marí, A; Martín-Albo, J; Martínez, A; Moiseenko, A; Monrabal, F; Monserrate, M; Monteiro, C M B; Mora, F J; Moutinho, L M; Vidal, J Muñoz; da Luz, H Natal; Navarro, G; Nebot-Guinot, M; Palma, R; Pérez, J; Aparicio, J L Pérez; Ripoll, L; Rodríguez, A; Rodríguez, J; Santos, F P; Santos, J M F dos; Seguí, L; Serra, L; Simón, A; Sofka, C; Sorel, M; Toledo, J F; Tomás, A; Torrent, J; Tsamalaidze, Z; Veloso, J F C A; Villar, J A; Webb, R C; White, J; Yahlali, N

    2014-01-01

    Ionization and scintillation produced by nuclear recoils in gaseous xenon at approximately 14 bar have been simultaneously observed in an electroluminescent time projection chamber. Neutrons from radioisotope $\\alpha$-Be neutron sources were used to induce xenon nuclear recoils, and the observed recoil spectra were compared to a detailed Monte Carlo employing estimated ionization and scintillation yields for nuclear recoils. The ability to discriminate between electronic and nuclear recoils using the ratio of ionization to primary scintillation is demonstrated. These results encourage further investigation on the use of xenon in the gas phase as a detector medium in dark matter direct detection experiments.

  15. Colorectal stenting for colonic obstruction: The indications, complications, effectiveness and outcome-5-Year review

    Energy Technology Data Exchange (ETDEWEB)

    Athreya, S. [Department of Radiology, Gartnavel General Hospital, Great Western Road, Glasgow (United Kingdom)]. E-mail: harshavbs@yahoo.com; Moss, J. [Department of Radiology, Gartnavel General Hospital, Great Western Road, Glasgow (United Kingdom)]. E-mail: j.moss@clinmed.gla.ac.uk; Urquhart, G. [Department of Radiology, Southern General Hospital, Glasgow (United Kingdom); Edwards, R. [Department of Radiology, Gartnavel General Hospital, Great Western Road, Glasgow (United Kingdom); Downie, A. [Department of Radiology, Victoria Infirmary, Glasgow (United Kingdom); Poon, F.W. [Department of Radiology, Royal Infirmary, Glasgow (United Kingdom)

    2006-10-15

    Introduction: Currently self-expanding metallic stents are being used for palliation and acute decompression of colonic obstruction. The aim of this study is to review our experience of using these metallic stents over a 5-year period. Materials and methods: Case records of 102 patients who had colorectal stenting between 1998 and 2004 were reviewed retrospectively. The indications for colorectal stenting, efficacy of the procedure in relieving the obstruction, complications and clinical outcome were analysed. Results: Ninety-nine patients had malignant disease and in three patients a benign cause of obstruction was demonstrated. All procedures were performed during normal working hours. Stenting was technically successful in 87 patients (85%). A single stent was placed in 80 patients. Seven patients required two stents. Of the successful cases, 67 had stents placed by fluoroscopy alone and 20 by a combined fluoroscopy/endoscopy procedure. Four percent had early complications (within 30 days) which included four perforations. There were late complications (over 30 days) in 9% which included five stent migrations, two blocked stents and one colovesical fistula. Ninety percent (n = 76) of the successful patients needed no further radiological or surgical intervention later. Survival ranged from 14 days to 2 years. Conclusion: Colorectal stenting when technically successful is an effective procedure for both preoperative and palliative decompression of colonic obstruction.

  16. Drug-eluting bioabsorbable magnesium stent.

    Science.gov (United States)

    Di Mario, Carlo; Griffiths, Huw; Goktekin, Omer; Peeters, Nicolas; Verbist, Jan; Bosiers, Marc; Deloose, Koen; Heublein, Bernhard; Rohde, Roland; Kasese, Victor; Ilsley, Charles; Erbel, Raimund

    2004-12-01

    Current stent technology is based on the use of permanent implants that remain life long in the vessel wall, far beyond the time required for the prosthesis to accomplish its main goals of sealing dissection and preventing wall recoil. With the possibility to implant long vessel segments using antiproliferative drugs to prevent restenosis, the practice of transforming the coronary vessels into stiff tubes with a full metal jacket covering all side branches and being unable to adjust to the long-term wall changes, including wall remodeling with lumen ectasia becomes a serious concern. In this article, we describe the first biodegradable stent based on a magnesium alloy that allows controlled corrosion with release to the vessel wall and the blood stream of a natural body component such as magnesium with beneficial antithrombotic, antiarrhythmic, and antiproliferative properties. We also discuss the animal experiments and the initial clinical applications in 20 patients with implants below the knee, with final results soon to be released, and the plans for the first coronary study. The results of these last two studies will indicate whether the absence of a permanent implant and the antiproliferative properties shown in animals are sufficient to prevent the restenotic process in humans or whether the prosthesis must be modified by adding the biodegradable coating with conventional antiproliferative drugs.

  17. Biomechanical Challenges to Polymeric Biodegradable Stents.

    Science.gov (United States)

    Soares, Joao S; Moore, James E

    2016-02-01

    Biodegradable implants have demonstrated clinical success in simple applications (e.g., absorbable sutures) and have shown great potential in many other areas of interventional medicine, such as localized drug delivery, engineered tissue scaffolding, and structural implants. For endovascular stenting and musculoskeletal applications, they can serve as temporary mechanical support that provides a smooth stress-transfer from the degradable implant to the healing tissue. However, for more complex device geometries, in vivo environments, and evolving load-bearing functions, such as required for vascular stents, there are considerable challenges associated with the use of biodegradable materials. A biodegradable stent must restore blood flow and provide support for a predictable appropriate period to facilitate artery healing, and subsequently, fail safely and be absorbed in a controllable manner. Biodegradable polymers are typically weaker than metals currently employed to construct stents, so it is difficult to ensure sufficient strength to keep the artery open and alleviate symptoms acutely while keeping other design parameters within clinically acceptable ranges. These design challenges are serious, given the general lack of understanding of biodegradable polymer behavior and evolution in intimal operating conditions. The modus operandi is mainly empirical and relies heavily on trial-and-error methodologies burdened by difficult, resource-expensive, and time-consuming experiments. We are striving for theoretical advancements systematizing the empirical knowledge into rational frameworks that could be cast into in silico tools for simulation and product development optimization. These challenges are evident when one considers that there are no biodegradable stents on the US market despite more than 30 years of development efforts (and currently only a couple with CE mark). This review summarizes previous efforts at implementing biodegradable stents, discusses the

  18. Endovascular Gene Delivery from a Stent Platform: Gene- Eluting Stents.

    Science.gov (United States)

    Fishbein, Ilia; Chorny, Michael; Adamo, Richard F; Forbes, Scott P; Corrales, Ricardo A; Alferiev, Ivan S; Levy, Robert J

    A synergistic impact of research in the fields of post-angioplasty restenosis, drug-eluting stents and vascular gene therapy over the past 15 years has shaped the concept of gene-eluting stents. Gene-eluting stents hold promise of overcoming some biological and technical problems inherent to drug-eluting stent technology. As the field of gene-eluting stents matures it becomes evident that all three main design modules of a gene-eluting stent: a therapeutic transgene, a vector and a delivery system are equally important for accomplishing sustained inhibition of neointimal formation in arteries treated with gene delivery stents. This review summarizes prior work on stent-based gene delivery and discusses the main optimization strategies required to move the field of gene-eluting stents to clinical translation.

  19. Cavity cooling below the recoil limit.

    Science.gov (United States)

    Wolke, Matthias; Klinner, Julian; Keßler, Hans; Hemmerich, Andreas

    2012-07-06

    Conventional laser cooling relies on repeated electronic excitations by near-resonant light, which constrains its area of application to a selected number of atomic species prepared at moderate particle densities. Optical cavities with sufficiently large Purcell factors allow for laser cooling schemes, avoiding these limitations. Here, we report on an atom-cavity system, combining a Purcell factor above 40 with a cavity bandwidth below the recoil frequency associated with the kinetic energy transfer in a single photon scattering event. This lets us access a yet-unexplored regime of atom-cavity interactions, in which the atomic motion can be manipulated by targeted dissipation with sub-recoil resolution. We demonstrate cavity-induced heating of a Bose-Einstein condensate and subsequent cooling at particle densities and temperatures incompatible with conventional laser cooling.

  20. Commissioning of a proton-recoil spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Nunes, J.C.; Faught, R.T

    2000-01-01

    Measurements of neutron fluence spectra in fields from bare and heavy-water-moderated {sup 252}Cf were made with a commercially available proton-recoil spectrometer (PRS) that covers 50 keV to 4.5 MeV. Data obtained from these measurements were compared with data from Bonner sphere spectrometry, Monte Carlo simulation and the open literature. Alterations to the input data file used in unfolding recoil-proton pulse-height distributions were made. Understanding the reasons for these changes and considering the effects of some of the results in an appreciation of the significance of parameters used in the unfolding. An uncertainty of 10% is estimated for values of fluence and ambient dose equivalent for the energy region covered by this PRS. (author)

  1. Recoil corrections in antikaon-deuteron scattering

    Directory of Open Access Journals (Sweden)

    Mai Maxim

    2016-01-01

    Full Text Available Using the non-relativistic effective field theory approach for K−d scattering, it is demonstrated that a systematic perturbative expansion of the recoil corrections in the parameter ξ = MK/mN is possible in spite of the fact that K−d scattering at low energies is inherently non-perturbative due to the large values of the K̄N scattering lengths. The first order correction to the K−d scattering length due to single insertion of the retardation term in the multiple-scattering series is calculated. The recoil effect turns out to be reasonably small even at the physical value of MK/mN ≃ 0:5.

  2. Experiments with recoil ions and other considerations

    Energy Technology Data Exchange (ETDEWEB)

    Cocke, C.L.

    1987-01-01

    Some opportunities in collisions physics with slow, multiply charged ions are addressed. A distinction between inner and outer shell collisions is drawn. The applicability of recoil ion sources to outer shell collision systems is discussed, with emphasis on the quality of the beam desired. An example of an inner shell collision is discussed, and the usefulness of not pushing the collision energy too low is pointed out. 13 refs., 14 figs.

  3. Optimal Control of Active Recoil Mechanisms

    Science.gov (United States)

    1977-02-01

    pressures in different chambers, rod pull are available and can be plotted. A linear state feedback control system is proposed to adapt this...desirable. A linear state feedback control system with variable gains is proposed in the report. A separate control law is designed for each...optimization algorithm to choose a feasible solution. 27 3.3 Results for M-37 Recoil Mechanism The linear state feedback control system and

  4. Polarization effects in recoil-induced resonances

    Science.gov (United States)

    Lazebnyi, D. B.; Brazhnikov, D. V.; Taichenachev, A. V.; Yudin, V. I.

    2017-01-01

    The effect of the field polarization on the amplitude of recoil-induced resonances (RIRs) is considered for laser-cooled free atoms and for atoms in a working magneto-optical trap (MOT). For all closed dipole transitions, explicit analytical expressions are obtained for the polarization dependence of the resonance amplitudes within a perturbation theory. Optimal polarization conditions are found for the observation of resonances.

  5. Endoscopic pancreatic duct stent placement for inflammatory pancreatic diseases

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The role of endoscopic therapy in the management of pancreatic diseases is continuously evolving; at present most pathological conditions of the pancreas are successfully treated by endoscopic retrograde cholangiopancreatography (ERCP) or endoscopic ultrasound (EUS),or both. Endoscopic placement of stents has played and still plays a major role in the treatment of chronic pancreatitis, pseudocysts, pancreas divisum, main pancreatic duct injuries, pancreatic fistulae, complications of acute pancreatitis, recurrent idiopathic pancreatitis,and in the prevention of post-ERCP pancreatitis. These stents are currently routinely placed to reduce intraductal hypertension, bypass obstructing stones, restore lumen patency in cases with dominant, symptomatic strictures,seal main pancreatic duct disruption, drain pseudocysts or fluid collections, treat symptomatic major or minor papilla sphincter stenosis, and prevent procedure-induced acute pancreatitis. The present review aims at updating and discussing techniques, indications, and results of endoscopic pancreatic duct stent placement in acute and chronic inflammatory diseases of the pancreas.

  6. Role of colonic stents in the management of colorectalcancers

    Institute of Scientific and Technical Information of China (English)

    2016-01-01

    Colorectal cancer is one of the commonly encounteredcancers across the Western World. In United Kingdom,this constitutes third most common ranked cancer andsecond most common ranked cause of cancer relateddeaths. Its acute presentation as a malignant colonicobstruction imposes challenges in its management.Colonic stent has been used for many years to alleviateSubmit a Manuscript http://www.wjgnet.com/esps/Help Desk: http://www.wjgnet.com/esps/helpdesk.aspxDOI: 10.4253/wjge.v8.i4.198World J Gastrointest Endosc 2016 February 25; 8(4): 198-204ISSN 1948-5190 (online)? 2016 Baishideng Publishing Group Inc. All rights reserved.acute obstruction in such cases allowing optimisationof patient's physiological status and adequate stagingof cancer. In this review, current literature evidenceregarding use of colonic stent in acute malignant colonicobstruction is critically appraised and recommendationson the use of colonic stent are advocated.

  7. Effects of coexisting polymorphisms of CYP2C19 and P2Y12 on clopidogrel responsiveness and clinical outcome in patients with acute coronary syndromes undergoing stent-based coronary intervention

    Institute of Scientific and Technical Information of China (English)

    TANG Xiao-fang; ZHANG Jia-hui; WANG Jing; HAN Ya-ling; XU Bo; QIAO Shu-bin; WU Yong-jian

    2013-01-01

    Background The CYP2C19 G681A single polymorphism has been proven to affect clopidogrel responsiveness.However,the effect of coexisting polymorphisms of other genes has not yet been reported in the Chinese population.This study investigated the effect of coexisting polymorphisms of CYP2C19 and P2Y12 on clopidogrel responsiveness and adverse clinical events in Chinese patients.Methods In 577 Han Chinese patients undergoing stent placement because of acute coronary syndrome had platelet reactivity assessed by thromboelastography,and the CYP2C19 G681A and P2Y12 C34T polymorphisms were detected by the ligase detection reaction.Primary clinical endpoints included cardiovascular death,nonfatal myocardial infarction,target vessel revascularization,and stent thrombosis.The secondary clinical endpoints were thrombolysis in myocardial infarction bleeding.The follow-up period was 12 months.Results Genotyping revealed 194 carriers of the wild type GG genotype of CYP2C19 and the wild type CC genotype of P2Y12 (group 1),102 carriers of the wild type GG genotype of CYP2C 19 and the mutational T allele of P2Y12 (group 2),163 carriers of the mutational A allele of CYP2C19 and the wild type CC genotype of P2Y12 (group 3),and 118 carriers of the mutational A allele of CYP2C19 and the mutational T allele of P2Y12 (group 4).Group 4 had the lowest ADP-inhibition (49.74±32.61) and the highest prevalence of clopidogrel low response (29.7%) of the four groups.The rate of the composite of primary clinical endpoints increased more in group 4 (8.5%) than in the other three groups; the rate of composite primary endpoints in group 2 (2.9%) and group 3 (3.7%) were not significantly different than that of group 1 (1.5%).Conclusion Coexisting polymorphisms of different genes affected clopidogrel responsiveness and clinical outcome more than single polymorphism in Chinese patients with acute coronary syndrome undergoing percutaneous coronary intervention.

  8. Arterial stenting with self-expandable and balloon-expandable endoprostheses

    NARCIS (Netherlands)

    W.J. van der Giessen (Wim); P.W.J.C. Serruys (Patrick); L.J. van Woerkens (L.); K.J. Beatt (Kevin); W.J. Visser (W.); J.F. Jongkind; R.H. van Bremen (Robert); E. Ridderhof; H. van Loon (Heleen); L.K. Soei (Lou Kie); H.M.M. van Beusekom (Heleen); P.D. Verdouw (Pieter)

    1990-01-01

    textabstractCoronary angioplasty is complicated by acute occlusion (within 24 hours) and late restenosis (within 6 months) in 2-5% and 20-40% of the cases, respectively. Vascular endoprostheses (stents) may provide the cardiologist with a solution to some of these complications. Several stent-device

  9. Elastic recoil detection analysis of ferroelectric films

    Energy Technology Data Exchange (ETDEWEB)

    Stannard, W.B.; Johnston, P.N.; Walker, S.R.; Bubb, I.F. [Royal Melbourne Inst. of Tech., VIC (Australia); Scott, J.F. [New South Wales Univ., Kensington, NSW (Australia); Cohen, D.D.; Dytlewski, N. [Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW (Australia)

    1996-12-31

    There has been considerable progress in developing SrBi{sub 2}Ta{sub 2}O{sub 9} (SBT) and Ba{sub O.7}Sr{sub O.3}TiO{sub 3} (BST) ferroelectric films for use as nonvolatile memory chips and for capacitors in dynamic random access memories (DRAMs). Ferroelectric materials have a very large dielectric constant ( {approx} 1000), approximately one hundred times greater than that of silicon dioxide. Devices made from these materials have been known to experience breakdown after a repeated voltage pulsing. It has been suggested that this is related to stoichiometric changes within the material. To accurately characterise these materials Elastic Recoil Detection Analysis (ERDA) is being developed. This technique employs a high energy heavy ion beam to eject nuclei from the target and uses a time of flight and energy dispersive (ToF-E) detector telescope to detect these nuclei. The recoil nuclei carry both energy and mass information which enables the determination of separate energy spectra for individual elements or for small groups of elements In this work ERDA employing 77 MeV {sup 127}I ions has been used to analyse Strontium Bismuth Tantalate thin films at the heavy ion recoil facility at ANSTO, Lucas Heights. 9 refs., 5 figs.

  10. Biocompatibility evaluation of NiTi SMA stent via intervenient therapy

    Institute of Scientific and Technical Information of China (English)

    FENG; Jing-su; LIU; Kun-peng; KOU; Ya-ming

    2005-01-01

    NiTi shape memory alloy (SMA) stent with film are the long-term implanted medical devices which could be used in human's organ, such as esophagus, bile duct, urethra-prostate and blood vessel, by intervene therapy. It is very important to have a good biocompatibility for implanted device. According to standard ISO 10993, we completed biocompatibility evaluation of NiTi stent that included following tests: cytotoxicity, sensitization, genotoxicity, hemolysis and acute systemic toxicity, The results of tests qualify the NiTi stent, and provide an optimistic conclusion for the eventual use of NiTi stent as implanted medical devices.

  11. Intravascular ultrasound assessed incomplete stent apposition and stent fracture in stent thrombosis after bare metal versus drug-eluting stent treatment the Nordic Intravascular Ultrasound Study (NIVUS)

    DEFF Research Database (Denmark)

    Kosonen, Petteri; Vikman, Saila; Jensen, Lisette Okkels;

    2013-01-01

    This prospective multicenter registry used intravascular ultrasound (IVUS) in patients with definite stent thrombosis (ST) to compare rates of incomplete stent apposition (ISA), stent fracture and stent expansion in patients treated with drug-eluting (DES) versus bare metal (BMS) stents. ST...... is a rare, but potential life threatening event after coronary stent implantation. The etiology seems to be multifactorial....

  12. Measurement of Low Energy Electronic Recoil Response and Electronic/Nuclear Recoils Discrimination in XENON100

    Science.gov (United States)

    Ye, Jingqiang; Xenon Collaboration

    2017-01-01

    The XENON100 detector uses liquid xenon time projection chamber to search for nuclear recoils(NR) caused by hypothetical Weakly Interacting Massive Particles (WIMPs). The backgrounds are mostly electronic recoils(ER), thus it's crucial to distinguish NR from ER. Using high statistical calibration data from tritiated methane, AmBe and other sources in XENON100, the ER/NR discrimination under different electric fields are measured. The Photon yield and recombination fluctuation of low energy electronic recoils under different fields will also be presented and compared to results from NEST and other experiments, which is crucial to understanding the response of liquid xenon detectors in the energy regime of searching dark matter.

  13. Renal Artery Stent Outcomes

    Science.gov (United States)

    Murphy, Timothy P.; Cooper, Christopher J.; Matsumoto, Alan H.; Cutlip, Donald E.; Pencina, Karol M.; Jamerson, Kenneth; Tuttle, Katherine R.; Shapiro, Joseph I.; D’Agostino, Ralph; Massaro, Joseph; Henrich, William; Dworkin, Lance D.

    2016-01-01

    BACKGROUND Multiple randomized clinical trials comparing renal artery stent placement plus medical therapy with medical therapy alone have not shown any benefit of stent placement. However, debate continues whether patients with extreme pressure gradients, stenosis severity, or baseline blood pressure benefit from stent revascularization. OBJECTIVES The study sought to test the hypothesis that pressure gradients, stenosis severity, and/or baseline blood pressure affects outcomes after renal artery stent placement. METHODS Using data from 947 patients with a history of hypertension or chronic kidney disease from the largest randomized trial of renal artery stent placement, the CORAL (Cardiovascular Outcomes in Renal Atherosclerotic Lesions) study, we performed exploratory analyses to determine if subsets of patients experienced better outcomes after stent placement than the overall cohort. We examined baseline stenosis severity, systolic blood pressure, and translesion pressure gradient (peak systolic and mean) and performed interaction tests and Cox proportional hazards analyses for the occurrence of the primary endpoint through all follow-up, to examine the effect of these variables on outcomes by treatment group. RESULTS There were no statistically significant differences in outcomes based on the examined variables nor were there any consistent nonsignificant trends. CONCLUSIONS Based on data from the CORAL randomized trial, there is no evidence of a significant treatment effect of the renal artery stent procedure compared with medical therapy alone based on stenosis severity, level of systolic blood pressure elevation, or according to the magnitude of the transstenotic pressure gradient. (Benefits of Medical Therapy Plus Stenting for Renal Atherosclerotic Lesions [CORAL]; NCT00081731) PMID:26653621

  14. Hyperperfusion syndrome after carotid stent angioplasty

    Energy Technology Data Exchange (ETDEWEB)

    Grunwald, I.Q.; Politi, M.; Reith, W.; Krick, C.; Karp, K.; Zimmer, A.; Struffert, T.; Kuehn, A.L.; Papanagiotou, P. [University of the Saarland, Department for Interventional and Diagnostic Neuroradiology, Homburg (Germany); Roth, C.; Haass, A. [University of the Saarland, Clinic for Neurology, Homburg (Germany)

    2009-03-15

    This study assesses the incidence and causes of hyperperfusion syndrome occurring after carotid artery stenting (CAS). We retrospectively reviewed the clinical database of 417 consecutive patients who were treated with CAS in our department to identify patients who developed hyperperfusion syndrome and/or intracranial hemorrhage. Magnetic resonance imaging (MRI) including fluid-attenuated inversion recovery and diffusion-weighted imaging was performed before and after CAS in 269 cases. A Spearman's rho nonparametric correlation was performed to determine whether there was a correlation between the occurrence/development of hyperperfusion syndrome and the patient's age, degree of stenosis on the stented and contralateral side, risk factors such as diabetes, smoking, hypertension, adiposity, gender and fluoroscopy time, and mean area of postprocedural lesions as well as preexisting lesions. Significance was established at p < 0.05. Of the 417 carotid arteries stented and where MRI was also completed, we found hyperperfusion syndrome in 2.4% (ten cases). Patients who had preexisting brain lesions (previous or acute stroke) were at a higher risk of developing hyperperfusion syndrome (p = 0.022; Spearman's rho test). We could not validate any correlation with the other patient characteristics. Extensive microvascular disease may be a predictor of hyperperfusion syndrome after carotid stent placement. We believe that further studies are warranted to predict more accurately which patients are at greater risk of developing this often fatal complication. (orig.)

  15. [Stent implantation as initial coronary interventional therapy? A theoretical model on clinical and economical consequences of in-stent restenosis].

    Science.gov (United States)

    Pfund, A; Wendland, G; Baer, F; Lauterbach, K; Höpp, H W

    2000-08-01

    The reduction of acute complications and late restenosis compared to conventional PTCA has led to a rapid increase in stent implantation as initial treatment for coronary stenosis. As a result, in-stent restenosis has become an important clinical and economical problem, especially the diffuse form, which is much more likely to reappear. In order to compare the consequences of initial stenting and initial angioplasty, we developed an analytic model, considering the differences between diffuse and focal in-stent restenosis. The simulation based on the optimized therapeutic proceeding following an elective 1-vessel revascularization of a 60-year-old patient, dealing with probabilities for acute complications and late restenosis taken from the literature and in-hospital costs obtained from 200 elective interventions. In the stent group 71.0% of patients were free of any target lesion-related event, compared to 60.2% in the PTCA group. Catheter reintervention was necessary for 32.1% of the patients initially treated with angioplasty and for 17.6% of the initially stented patients, whereas 7.7% of the stent patients had to undergo elective bypass surgery as final treatment compared to 2.8% in the PTCA arm. Long-term medical costs for initial stenting (6,237 Euros) were 14% higher than for conventional PTCA (5,345 Euros). Taking also into consideration the indirect costs (loss of productivity) for a collective with an employment rate of 50%, the difference between stent implantation (9,067 Euros) and angioplasty (8,581 Euros) is smaller. Initial treatment of coronary stenosis by stent implantation decreases the rate of repeat revascularization compared to initial PTCA, but there is a greater likelihood that elective bypass surgery will become necessary. This difference in following treatment is related to the occurrence of diffuse in-stent restenosis. When calculating the long-term costs stenting still appeared to be more expensive than PTCAA because the savings in

  16. The virtual histology intravascular ultrasound appearance of newly placed drug-eluting stents.

    Science.gov (United States)

    Kim, Sang-Wook; Mintz, Gary S; Hong, Young-Joon; Pakala, Rajbabu; Park, Kyung-Sook; Pichard, Augusto D; Satler, Lowell F; Kent, Kenneth M; Suddath, William O; Waksman, Ron; Weissman, Neil J

    2008-11-01

    Intravascular ultrasound (IVUS) is used before and after intervention and at follow-up to assess the quality of the acute result as well as the long-term effects of stent implantation. Virtual histology (VH) IVUS classifies tissue into fibrous and fibrofatty plaque, dense calcium, and necrotic core. Although most interventional procedures include stent implantation, VH IVUS classification of stent metal has not been validated. In this study, the VH IVUS appearance of acutely implanted stents was assessed in 27 patients (30 lesions). Most stent struts (80%) appeared white (misclassified as "calcium") surrounded by red (misclassified as "necrotic core"); 2% appeared just white, and 17% were not detectable (compared with grayscale IVUS because of the software-imposed gray medial stripe). The rate of "white surrounded by red" was similar over the lengths of the stents; however, undetectable struts were mostly at the distal edges (31%). Quantitatively, including the struts within the regions of interest increased the amount of "calcium" from 0.23 +/- 0.35 to 1.07 +/- 0.66 mm(2) (p stents have an appearance that can be misclassified by VH IVUS as "calcium with or without necrotic core." It is important not to overinterpret VH IVUS studies of chronically implanted stents when this appearance is observed at follow-up. A separate classification for stent struts is necessary to avoid these misconceptions and misclassifications.

  17. Drug-eluting stents to prevent stent thrombosis and restenosis.

    Science.gov (United States)

    Im, Eui; Hong, Myeong-Ki

    2016-01-01

    Although first-generation drug-eluting stents (DES) have significantly reduced the risk of in-stent restenosis, they have also increased the long-term risk of stent thrombosis. This safety concern directly triggered the development of new generation DES, with innovations in stent platforms, polymers, and anti-proliferative drugs. Stent platform materials have evolved from stainless steel to cobalt or platinum-chromium alloys with an improved strut design. Drug-carrying polymers have become biocompatible or biodegradable and even polymer-free DES were introduced. New limus-family drugs (such as everolimus, zotarolimus or biolimus) were adopted to enhance stent performances. As a result, these new DES demonstrated superior vascular healing responses on intracoronary imaging studies and lower stent thrombotic events in actual patients. Recently, fully-bioresorbable stents (scaffolds) have been introduced, and expanding their applications. In this article, the important concepts and clinical results of new generation DES and bioresorbable scaffolds are described.

  18. Stent Fracture after Everolimus-Eluting Stent Implantation

    Directory of Open Access Journals (Sweden)

    Ali S. Almasood

    2011-01-01

    Full Text Available Compared with bare-metal stents, drug-eluting stents (DES have greatly reduced the risk of in-stent restenosis (ISR by inhibiting neointimal growth. Nevertheless, DES are still prone to device failure, which may lead to cardiac events. Recently, stent fracture (SF has emerged as a potential mechanism of DES failure that is associated with ISR. Stent fracture is strongly related to stent type, and prior reports suggest that deployment of sirolimus eluting stents (SES may be associated with a higher risk of SF compared to other DES. Everolimus eluting stents (EESs represent a new generation of DES with promising results. The occurrence of SF with EES has not been well established. The present paper describes two cases of EES fracture associated with ISR.

  19. Development of a dynamic in vitro model of a stented blood vessel to evaluate the effects of stent strut material selection and surface coating on smooth muscle cell response

    Science.gov (United States)

    Winn, Bradley Huegh

    Cardiovascular disease is the leading cause of mortality in The United States and Europe, accounting for approximately half of all deaths. The most common form of cardiovascular disease is atherosclerosis, which is characterized by the formation of fatty atheromatous plaques that can grow to occlude the vessel lumen, thus causing ischemia distal to the occlusion. This is commonly treated using balloon angioplasty, which is usually done in conjunction with the deployment of a stent. Stent deployment helps hold the vessel open following the local injury caused by balloon inflation and prevents elastic recoil and subsequent negative remodeling. Stenting has been shown to significantly reduce restenosis rates from approximately 20-50% without a stent to about 10-30% with stent deployment. However, restenosis still remains the main cause of long-term stent failure. In basic terms, a balloon angioplasty procedure is a forceful displacement of an atherosclerotic lesion serving to widen the vessel lumen to increase blood flow. This procedure causes stretching of the vessel wall, tears in the atherosclerotic plaques, and general damage to the vessel in turn signaling a complex cascade of thrombosis, inflammation, intimal thickening, and vascular remodeling. Stent deployment also further complicates the immunological response by triggering a foreign body response from the implantation of a biomaterial into the body. When performing an angioplasty procedure, particularly in conjunction with stent deployment, a certain degree of vascular injury is inevitable. However, the initial injury can be further complicated by the body's local reaction to the implanted biomaterial, the severity of which can ultimately dictate the degree of restenosis and subsequently affect procedural success. The proliferative response of VSMCs to the various afore mentioned stimuli results in the formation of often copious amounts of neointimal tissue, generally known as intimal hyperplasia. The

  20. Scintillation of liquid neon from electronic and nuclear recoils

    CERN Document Server

    Nikkel, J A; Lippincott, W H; McKinsey, D N

    2006-01-01

    We have measured the time dependence of scintillation light from electronic and nuclear recoils in liquid neon, finding a slow time constant of 15.4+-0.2 us. Pulse shape discrimination is investigated as a means of identifying event type in liquid neon. Finally, the nuclear recoil scintillation efficiency is measured to be 0.26+-0.03 for 387 keV nuclear recoils.

  1. Nanomaterial coatings applied on stent surfaces.

    Science.gov (United States)

    Bagheri, Mahsa; Mohammadi, Marzieh; Steele, Terry Wj; Ramezani, Mohammad

    2016-05-01

    The advent of percutaneous coronary intervention and intravascular stents has revolutionized the field of interventional cardiology. Nonetheless, in-stent restenosis, inflammation and late-stent thrombosis are the major obstacles with currently available stents. In order to enhance the hemocompatibility of stents, advances in the field of nanotechnology allow novel designs of nanoparticles and biomaterials toward localized drug/gene carriers or stent scaffolds. The current review focuses on promising polymers used in the fabrication of newer generations of stents with a short synopsis on atherosclerosis and current commercialized stents, nanotechnology's impact on stent development and recent advancements in stent biomaterials is discussed in context.

  2. Cobalt chromium stents versus stainless steel stents in diabetic patients

    Directory of Open Access Journals (Sweden)

    Mahmoud Ahmed Tantawy

    2014-03-01

    Conclusions: We concluded that no significant statistical difference was found between the two stents (cobalt-chromium alloy bare metal stent versus conventional bare metal stainless steel stent in diabetic patients regarding (initial procedural success, in-hospital complications, the incidence of ISR at follow up, event-free survival at follow up.

  3. Recoil Considerations for Shoulder-Fired Weapons

    Science.gov (United States)

    2012-05-01

    2012) Steyr 15.2 mm 35 g 1450 m/s 39.6 lb 11.4 Burns (2012) Type 97 (Japanese) 20 mm 162 g 790 m/s 130 lb 28.7 Burns (2012) 12HB00 ( Remington ...shotgun 0.727 in 807 gr (12 × 00) 1225 ft/s 7.0 lb 4.37 Remington (2011) Remington Express 12B0 shotgun 0.727 in 580 gr (12 × 0) 1275 ft/s...7.0 lb 3.28 Remington 5 Table 3. Recoil-related characteristics of selected shoulder-fired weapons cited in table 1. Nomenclature

  4. Neutron electric form factor via recoil polarimetry

    Energy Technology Data Exchange (ETDEWEB)

    Madey, Richard; Semenov, Andrei; Taylor, Simon; Aghalaryan, Aram; Crouse, Erick; MacLachlan, Glen; Plaster, Bradley; Tajima, Shigeyuki; Tireman, William; Yan, Chenyu; Ahmidouch, Abdellah; Anderson, Brian; Asaturyan, Razmik; Baker, O; Baldwin, Alan; Breuer, Herbert; Carlini, Roger; Christy, Michael; Churchwell, Steve; Cole, Leon; Danagoulian, Samuel; Day, Donal; Elaasar, Mostafa; Ent, Rolf; Farkhondeh, Manouchehr; Fenker, Howard; Finn, John; Gan, Liping; Garrow, Kenneth; Gueye, Paul; Howell, Calvin; Hu, Bitao; Jones, Mark; Kelly, James; Keppel, Cynthia; Khandaker, Mahbubul; Kim, Wooyoung; Kowalski, Stanley; Lung, Allison; Mack, David; Manley, D; Markowitz, Pete; Mitchell, Joseph; Mkrtchyan, Hamlet; Opper, Allena; Perdrisat, Charles; Punjabi, Vina; Raue, Brian; Reichelt, Tilmann; Reinhold, Joerg; Roche, Julie; Sato, Yoshinori; Seo, Wonick; Simicevic, Neven; Smith, Gregory; Stepanyan, Samuel; Tadevosyan, Vardan; Tang, Liguang; Ulmer, Paul; Vulcan, William; Watson, John; Wells, Steven; Wesselmann, Frank; Wood, Stephen; Yan, Chen; Yang, Seunghoon; Yuan, Lulin; Zhang, Wei-Ming; Zhu, Hong Guo; Zhu, Xiaofeng

    2003-05-01

    The ratio of the electric to the magnetic form factor of the neutron, G_En/G_Mn, was measured via recoil polarimetry from the quasielastic d({pol-e},e'{pol-n)p reaction at three values of Q^2 [viz., 0.45, 1.15 and 1.47 (GeV/c)^2] in Hall C of the Thomas Jefferson National Accelerator Facility. Preliminary data indicate that G_En follows the Galster parameterization up to Q^2 = 1.15 (GeV/c)^2 and appears to rise above the Galster parameterization at Q^2 = 1.47 (GeV/c)^2.

  5. Clinical results from first use of prostate stent as fiducial for radiotherapy of prostate cancer

    Energy Technology Data Exchange (ETDEWEB)

    Carl, Jesper; Nielsen, Jane (Dept. of Medical Physics, Dept. of Oncology, Aalborg Hospital, Aarhus Univ. Hospital, Aalborg (Denmark)), e-mail: jhc@rn.dk; Holmberg, Mats (Dept. of Oncology, Aalborg Hospital, Aarhus Univ. Hospital, Aalborg (Denmark)); Larsen, Erik Hoejkjaer; Fabrin, Knud (Dept. of Urology, Aalborg Hospital, Aarhus Univ. Hospital, Aalborg (Denmark)); Fisker, Rune V. (Dept. of Radiology, Aalborg Hospital, Aarhus Univ. Hospital, Aalborg (Denmark))

    2011-05-15

    Purpose. A clinical feasibility study using a removable prostate stent as fiducial for image-guided radiotherapy (IGRT) of localized prostate cancer (PC). Material and methods. The study included patients with local or locally advanced PC. The clinical target volume (CTV) was outlined on magnetic resonance (MR) images co-registered to planning computer tomography (CT) images. Daily online IGRT was delivered using the stent as fiducial. Risk of migration was estimated using multiple MR. Acute urinary toxicity was scored using the international prostate symptom score (IPSS). Late gastro-intestinal (GI) and genito-urinary (GU) toxicity was scored using the Radio Therapy Oncology Group (RTOG) score, biochemical failure (BF) was defined as an elevation of prostate specific antigen (PSA) above nadir plus 2 ng/ml after radiotherapy. Results. One hundred men were enrolled in the study. Ninety completed radiotherapy with the stent as fiducial. No migration of the stent was seen, but three cases of dislocation of the stent to the bladder were observed. Acute urinary toxicity based on IPSS was comparable to toxicity in patients who had gold markers (GM) as fiducials. Removal of the stent was associated with a high frequency of urinary retention. Late GI and GU toxicity and BF were comparable to those of other studies, but longer observation time is needed. Conclusions. This study reports the first clinical results of using a prostate stent as fiducial. No migration of the stent observed. Dislocation of the stent to the urinary bladder was observed in three cases, requiring removal of the stent and insertion of a new fiducial. Acute toxicity during radiotherapy evaluated from IPSS was comparable to toxicity in patients with GM. Removal of the stent was associated with a high frequency of post procedural urinary retention. Late toxicity and BF were comparable to those of other studies, though longer observation time is needed

  6. Treatment of Malignant Biliary Obstruction with a PTFE-Covered Self-Expandable Nitinol Stent

    Energy Technology Data Exchange (ETDEWEB)

    Han, Young-Min; Kwak, Hyo-Sung; Jin, Gong-Yong; Lee, Seung-Ok; Chung, Gyung-Ho [Chonbuk National University Medical School and Hospital, Chonju (Korea, Republic of)

    2007-10-15

    We wanted to determine the technical and clinical efficacy of using a PTFE-covered self-expandable nitinol stent for the palliative treatment of malignant biliary obstruction. Thirty-seven patients with common bile duct strictures caused by malignant disease were treated by placing a total of 37 nitinol PTFE stents. These stents were covered with PTFE with the exception of the last 5 mm at each end; the stent had an unconstrained diameter of 10 mm and a total length of 50 80 mm. The patient survival rate and stent patency rate were calculated by performing Kaplan-Meier survival analysis. The bilirubin, serum amylase and lipase levels before and after stent placement were measured and then compared using a Wilcoxon signed-rank test. The average follow-up duration was 27.9 weeks (range: 2 81 weeks). Placement was successful in all cases. Seventy-six percent of the patients (28/37) experienced adequate palliative drainage for the remainder of their lives. There were no immediate complications. Three patients demonstrated stent sludge occlusion that required PTBD (percutaneous transhepatic biliary drainage) irrigation. Two patients experienced delayed stent migration with stone formation at 7 and 27 weeks of follow-up, respectively. Stent insertion resulted in acute elevations of the amylase and lipase levels one day after stent insertion in 11 patients in spite of performing endoscopic sphincterotomy (4/6). The bilirubin levels were significantly reduced one week after stent insertion (p < 0.01). The 30-day mortality rate was 8% (3/37), and the survival rates were 49% and 27% at 20 and 50 weeks, respectively. The primary stent patency rates were 85%, and 78% at 20 and 50 weeks, respectively. The PTFE-covered self-expandable nitinol stent is safe to use with acceptable complication rates. This study is similar to the previous studies with regard to comparing the patency rates and survival rates.

  7. Future developments in biliary stenting

    Directory of Open Access Journals (Sweden)

    Hair CD

    2013-06-01

    Full Text Available Clark D Hair,1 Divyesh V Sejpal21Department of Medicine, Section of Gastroenterology and Hepatology, Baylor College of Medicine, Houston, TX, USA; 2Department of Medicine, Section of Gastroenterology, Hofstra North Shore-LIJ School of Medicine, North Shore University Hospital, Manhasset, NY, USAAbstract: Biliary stenting has evolved dramatically over the past 30 years. Advancements in stent design have led to prolonged patency and improved efficacy. However, biliary stenting is still affected by occlusion, migration, anatomical difficulties, and the need for repeat procedures. Multiple novel plastic biliary stent designs have recently been introduced with the primary goals of reduced migration and improved ease of placement. Self-expandable bioabsorbable stents are currently being investigated in animal models. Although not US Food and Drug Administration approved for benign disease, fully covered self-expandable metal stents are increasingly being used in a variety of benign biliary conditions. In malignant disease, developments are being made to improve ease of placement and stent patency for both hilar and distal biliary strictures. The purpose of this review is to describe recent developments and future directions of biliary stenting.Keywords: plastic stents, self-expandable metal stents, drug eluting stents, bioabsorbable stents, malignant biliary strictures, benign biliary strictures

  8. Therapeutic effect and safety of Firebird stent combined tirofiban on acute myocardial infarction%Firebird 支架联合替罗非班用于急性心肌梗死中的疗效及安全性

    Institute of Scientific and Technical Information of China (English)

    刘远萍; 郝亚荣

    2015-01-01

    目的:评价Firebird支架联合替罗非班用于急性心肌梗死(AMI)中的疗效及安全性。方法:选择2011年8月至2013年8月我院收治的86例AMI患者,依据随机数字表法患者被分为:联合治疗组(50例, Firebird支架联合替罗非班)和常规治疗组(36例,裸金属支架)。对患者进行12~18个月的随访,比较两组临床疗效、临床事件发生率。结果:PCI术后,与常规治疗组比较,联合治疗组患者TIMI分级1-2级比例(13.9%比4.0%)明显减少,3~4级比例(86.1%比96.0%)明显增加,校正TIMI计帧数[(29.2±4.4)比(21.4±5.1)]明显减少, P均<0.05;术后6个月,与常规治疗组比较,联合治疗组的亚急性血栓(2.8%比0%)、心肌梗死(2.8%比0%)发生率均明显降低( P均<0.05),术后12个月,与常规治疗组比较,联合治疗组的心绞痛(16.7%比6.0%)、亚急性血栓(11.1%比0%)、心肌梗死(8.3%比0%)、心力衰竭(2.8%比0%)、再入院(11.1%比0%)发生率均明显降低(P<0.05或<0.01)。结论:Firebird支架联合替罗非班用于急性心肌梗死中的疗效显著,且安全可靠,值得推广。%Objective:To evaluate therapeutic effect and safety of Firebird stent combined tirofiban on acute myocar‐dial infarction (AMI) .Methods :A total of 86 AMI patients treated in our hospital from Aug 2011 to Aug 2013 were selected .According to random number table method ,patients were divided into combined treatment group (n=50 , received Firebird stenting combined tirofiban treatment ) and routine treatment group (n=36 ,received bare metal stenting) .Patients were followed up for 12~18 months ,therapeutic effects ,incidence rates of clinical events were compared between two groups .Results:After PCI ,compared with routine treatment group ,there were significant reductions in percentage of TIMI class 1~2 (13.9% vs .4

  9. Zotarolimus-eluting durable-polymer-coated stent versus a biolimus-eluting biodegradable-polymer-coated stent in unselected patients undergoing percutaneous coronary intervention (SORT OUT VI)

    DEFF Research Database (Denmark)

    Raungaard, Bent; Jensen, Lisette Okkels; Tilsted, Hans-Henrik

    2015-01-01

    BACKGROUND: New-generation drug-eluting coronary stents have reduced the risk of coronary events, especially in patients with complex disease or lesions. To what extent different stent platforms, polymers, and antiproliferative drugs affect outcomes, however, is unclear. We investigated the safety...... and efficacy of a third-generation stent by comparing a highly biocompatible durable-polymer-coated zotarolimus-eluting stent with a biodegradable-polymer-coated biolimus-eluting stent. METHODS: This open-label, randomised, multicentre, non-inferiority trial was done at three sites across western Denmark. All...... patients who presented with stable coronary artery disease or acute coronary syndromes and at least one coronary artery lesion (more than 50% stenosis) from March, 2011, to August, 2012, were assessed for eligibility. Patients were randomly assigned in a 1:1 ratio to receive either the durable-polymer...

  10. Chemico-physical characterisation and in vivo biocompatibility assessment of DLC-coated coronary stents.

    Science.gov (United States)

    Castellino, Micaela; Stolojan, Vlad; Virga, Alessandro; Rovere, Massimo; Cabiale, Karine; Galloni, Marco R; Tagliaferro, Alberto

    2013-01-01

    The vast majority of stent thrombosis occurs in the acute and sub-acute phases and is more common in patients with acute coronary syndromes, due to the thrombotic milieu where stent struts are positioned. Stent thrombosis is likely due to incomplete tissue coverage of metallic stents as the contact between metallic stents and blood elements may lead to platelet adhesion and trigger vessel thrombosis. If a stent is covered after 7 days, the risk that it will be found uncovered at later stages is very low (<1%). In this article, we demonstrate that diamond-like carbon (DLC) coatings, deposited by physical vapour deposition, promote rapid endothelisation of coronary stent devices, with very low platelets activation, reducing thrombotic clots. We relate these behaviours to the surface and bulk material properties of the DLC films, subjected to a comprehensive chemico-physical characterisation using several techniques (X-ray photoelectron spectroscopy, atomic force microscopy, field-emission scanning electron microscope, transmission electron microscopy combined with electron energy loss spectroscopy, Raman and dispersive X-ray spectroscopy). In vivo studies, conducted on 24 pigs, have shown complete endothelisation after 7 days, with no fibrin mesh and with only rare monocytes scattered on the endothelial layer while 30 and 180 days tests have shown reduced inflammatory activation and a complete stabilisation of the vessel healing, with a minimal neointimal proliferation. The integral and permanent DLC film coating improves haemo- and bio-compatibility and leads to an excellent early vessel healing of the stent whilst the extremely thin strut thickness reduces the amount of late neointima and consequently the risk of late restenosis. These data should translate into a reduced acute and sub-acute stent thrombosis.

  11. A thermal analogy for modelling drug elution from cardiovascular stents.

    Science.gov (United States)

    Hose, D R; Narracott, A J; Griffiths, B; Mahmood, S; Gunn, J; Sweeney, D; Lawford, P V

    2004-10-01

    Restriction of blood flow by the narrowing or occlusion of arteries is one of the most common presentations of cardiovascular disease. One treatment involves the introduction of a metal scaffold, or stent, designed to prevent recoil and to provide structural stability to the vessel. On the occasions that this treatment is ineffective, failure is usually associated with re-invasion of tissue. This can be prevented by local delivery of drugs which inhibit tissue growth. The drug might be delivered locally in a polymer coating on the stent. This paper develops and explores the use of a thermal analogue of the drug delivery process and the associated three-dimensional convection-diffusion equation to model the spatial and temporal distribution of drug concentration within the vessel wall. This allows the routine use of commercial finite element analysis software to investigate the dynamics of drug distribution, assist in the understanding of the treatment process and develop improved delivery systems. Two applications illustrate how the model might be used to investigate the effects of controllable or measurable parameters on the progression of the process. It is demonstrated that the geometric characteristics of the stent can have significant impact on the homogeneity of the dosing in the vessel wall.

  12. Heavy ion recoil spectrometry of barium strontium titanate films

    Science.gov (United States)

    Stannard, W. B.; Johnston, P. N.; Walker, S. R.; Bubb, I. F.; Scott, J. F.; Cohen, D. D.; Dytlewski, N.; Martin, J. W.

    1995-05-01

    Thin films of barium strontium titanate have been analysed using heavy ion recoil spectrometry with 77 and 98 MeV 127I ions at the new heavy ion recoil facility at ANSTO, Lucas Heights. New calibration procedures have been developed for quantitative analysis. Energy spectra for each of the elements present reveal interdiffusion that was not previously known.

  13. Comparison of the Recoil of Conventional and Electromagnetic Cannon

    Directory of Open Access Journals (Sweden)

    Edward M. Schmidt

    2001-01-01

    Full Text Available The recoil from an electromagnetic (EM railgun is discussed and compared with that from conventional, propellant gas driven cannon. It is shown that, under similar launch conditions, the recoil of the EM gun is less than that of the powder gun; however, use of a muzzle brake on a powder gun can alter this relative behavior.

  14. Nitinol Stent Oversizing in Patients Undergoing Popliteal Artery Revascularization: A Finite Element Study.

    Science.gov (United States)

    Gökgöl, Can; Diehm, Nicolas; Nezami, Farhad Rikhtegar; Büchler, Philippe

    2015-12-01

    Nitinol stent oversizing is frequently performed in peripheral arteries to ensure a desirable lumen gain. However, the clinical effect of mis-sizing remains controversial. The goal of this study was to provide a better understanding of the structural and hemodynamic effects of Nitinol stent oversizing. Five patient-specific numerical models of non-calcified popliteal arteries were developed to simulate the deployment of Nitinol stents with oversizing ratios ranging from 1.1 to 1.8. In addition to arterial biomechanics, computational fluid dynamics methods were adopted to simulate the physiological blood flow inside the stented arteries. Results showed that stent oversizing led to a limited increase in the acute lumen gain, albeit at the cost of a significant increase in arterial wall stresses. Furthermore, localized areas affected by low Wall Shear Stress increased with higher oversizing ratios. Stents were also negatively impacted by the procedure as their fatigue safety factors gradually decreased with oversizing. These adverse effects to both the artery walls and stents may create circumstances for restenosis. Although the ideal oversizing ratio is stent-specific, this study showed that Nitinol stent oversizing has a very small impact on the immediate lumen gain, which contradicts the clinical motivations of the procedure.

  15. Neoatherosclerosis:Coronary stents seal atherosclerotic lesions but result in making a new problem of atherosclerosis

    Institute of Scientific and Technical Information of China (English)

    Hidenori; Komiyama; Masamichi; Takano; Noritake; Hata; Yoshihiko; Seino; Wataru; Shimizu; Kyoichi; Mizuno

    2015-01-01

    Chronic inflammation of the native vessel wall with infiltration of lipid-laden foamy macrophages through impaired endothelium results in atherosclerosis. Percutaneous coronary intervention, including metallic stent implantation, is now widely utilized for the treatment of atherosclerotic lesions of the coronary artery. Baremetal stents and the subsequently developed drugeluting stents seal the atherosclerosis and resolve lumen stenosis or obstruction of the epicardial coronary artery and myocardial ischemia. After stent implantation, neointima proliferates within the stented segment. Chronic inflammation caused by a foreign body reaction to the implanted stent and subsequent neovascularization, which is characterized by the continuous recruitment of macrophages into the vessel, result in the transformation of the usual neointima into an atheromatous neointima. Neointima with an atherosclerotic appearance, such as that caused by thin-cap fibroatheromas, is now recognized as neoatherosclerosis, which can sometimes cause in-stent restenosis and acute thrombotic occlusion originating from the stent segment following disruption of the atheroma. Neoatherosclerosis is emerging as a new coronary stent-associated problem that has not yet been resolved. In this review article, we will discuss possible mechanisms, clinical challenges, and the future outlook of neoatherosclerosis.

  16. Drug-eluting stents: current issues

    NARCIS (Netherlands)

    P.W.J.C. Serruys (Patrick); A.T.L. Ong (Andrew)

    2005-01-01

    textabstractEarly stent thrombosis occurs in about 1% to 1.5% of patients with drug-eluting stents, very similar to the rate with bare-metal stents. Late stent thrombosis is more of a concern with drug-eluting stents, with an incidence of at least 0.35%. I would urge caution if you feel you have to

  17. Biodegradable-Polymer Biolimus-Eluting Stents versus Durable-Polymer Everolimus-Eluting Stents at One-Year Follow-Up: A Registry-Based Cohort Study.

    Science.gov (United States)

    Parsa, Ehsan; Saroukhani, Sepideh; Majlessi, Fereshteh; Poorhosseini, Hamidreza; Lofti-Tokaldany, Masoumeh; Jalali, Arash; Salarifar, Mojtaba; Nematipour, Ebrahim; Alidoosti, Mohammad; Aghajani, Hassan; Amirzadegan, Alireza; Kassaian, Seyed Ebrahim

    2016-04-01

    We compared outcomes of percutaneous coronary intervention patients who received biodegradable-polymer biolimus-eluting stents with those who received durable-polymer everolimus-eluting stents. At Tehran Heart Center, we performed a retrospective analysis of the data from January 2007 through December 2011 on 3,270 consecutive patients with coronary artery disease who underwent percutaneous coronary intervention with the biodegradable-polymer biolimus-eluting stent or the durable-polymer everolimus-eluting stent. We excluded patients with histories of coronary artery bypass grafting or percutaneous coronary intervention, acute ST-segment-elevation myocardial infarction, or the implantation of 2 different stent types. Patients were monitored for 12 months. The primary endpoint was a major adverse cardiac event, defined as a composite of death, nonfatal myocardial infarction, and target-vessel and target-lesion revascularization. Durable-polymer everolimus-eluting stents were implanted in 2,648 (81%) and biodegradable-polymer biolimus-eluting stents in 622 (19%) of the study population. There was no significant difference between the 2 groups (2.7% vs 2.7%; P=0.984) in the incidence of major adverse cardiac events. The cumulative adjusted probability of major adverse cardiac events in the biodegradable-polymer biolimus-eluting stent group did not differ from that of such events in the durable-polymer everolimus-eluting stent group (hazard ratio=0.768; 95% confidence interval, 0.421-1.44; P=0.388). We conclude that in our patients the biodegradable-polymer biolimus-eluting stent was as effective and safe, during the 12-month follow-up period, as was the durable-polymer everolimus-eluting stent.

  18. D-Brane Recoil Mislays Information

    CERN Document Server

    Ellis, Jonathan Richard; Nanopoulos, Dimitri V

    1998-01-01

    We discuss the scattering of a light closed-string state off a $D$ brane, taking into account quantum recoil effects on the latter, which are described by a pair of logarithmic operators. The light-particle and $D$-brane subsystems may each be described by a world-sheet with an external source due to the interaction between them. This perturbs each subsystem away from criticality, which is compensated by dressing with a Liouville field whose zero mode we interpret as time. The resulting evolution equations for the $D$ brane and the closed string are of Fokker-Planck and modified quantum Liouville type, respectively. The apparent entropy of each subsystem increases as a result of the interaction between them, which we interpret as the loss of information resulting from non-observation of the other entangled subsystem. We speculate on the possible implications of these results for the propagation of closed strings through a dilute gas of virtual $D$ branes.

  19. A proton recoil telescope for neutron spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Donzella, A., E-mail: antonietta.donzella@ing.unibs.i [Universita di Brescia, 38 Via Branze, I-25123 Brescia (Italy); INFN Sezione di Pavia, 6 Via Bassi, I-27100 Pavia (Italy); Barbui, M. [INFN Laboratori Nazionali di Legnaro, 2 Viale dell' Universita, I-35020 Legnaro, Padova (Italy); Bocci, F. [INFN and Universita di Pavia, 6 Via Bassi, I-27100 Pavia (Italy); Bonomi, G. [Universita di Brescia, 38 Via Branze, I-25123 Brescia (Italy); INFN Sezione di Pavia, 6 Via Bassi, I-27100 Pavia (Italy); Cinausero, M. [INFN Laboratori Nazionali di Legnaro, 2 Viale dell' Universita, I-35020 Legnaro, Padova (Italy); Fabris, D. [INFN and Universita di Padova, 8 Via Marzolo, I-35131 Padova (Italy); Fontana, A. [INFN Sezione di Pavia, 6 Via Bassi, I-27100 Pavia (Italy); Giroletti, E. [INFN and Universita di Pavia, 6 Via Bassi, I-27100 Pavia (Italy); Lunardon, M.; Moretto, S.; Nebbia, G. [INFN and Universita di Padova, 8 Via Marzolo, I-35131 Padova (Italy); Necchi, M.M. [Universita di Brescia, 38 Via Branze, I-25123 Brescia (Italy); Pesente, S. [INFN and Universita di Padova, 8 Via Marzolo, I-35131 Padova (Italy); Prete, G.; Rizzi, V. [INFN Laboratori Nazionali di Legnaro, 2 Viale dell' Universita, I-35020 Legnaro, Padova (Italy); Viesti, G. [INFN and Universita di Padova, 8 Via Marzolo, I-35131 Padova (Italy); Zenoni, A. [Universita di Brescia, 38 Via Branze, I-25123 Brescia (Italy); INFN Sezione di Pavia, 6 Via Bassi, I-27100 Pavia (Italy)

    2010-01-21

    A new proton recoil telescope (PRT) detector is presented: it is composed by an active multilayer of segmented plastic scintillators as neutron to proton converter, by two silicon strip detectors and by a final thick CsI(Tl) scintillator. The PRT can be used to measure neutron spectra in the range 2-160 MeV. The detector characteristics have been studied in detail with the help of Monte Carlo simulations. The overall energy resolution of the system ranges from about 20% at the lowest neutron energy to about 2% at 160 MeV. The global efficiency is about 3x10{sup -5}. Experimental tests have been performed by using the reaction {sup 13}C(d,n) at 40 MeV deuteron energy.

  20. Lithium recoil measurement without a subrecoil sample

    CERN Document Server

    Cassella, Kayleigh; Estey, Brian; Feng, Yanying; Lai, Chen; Müller, Holger

    2016-01-01

    We report both the first atom interferometer with a low-mass, laser-cooled atom (lithium-7) and the first simultaneous conjugate Ramsey-Bord\\'e interferometers with an atomic ensemble not cooled or selected to subrecoil speeds. Above the recoil temperature, fast thermal motion of atoms leads to overlapped interferometers whose outputs tend to cancel. We avoid such cancellation using the two-photon detuning from Raman resonance to control the relative phase between these conjugate interferometers. To prevent magnetic dephasing, we present optical pumping to the magnetically-insensitive state using the well-resolved $D_1$ line. These techniques allow the use of "warm" atoms for Ramsey-Bord\\'e interferometers, which broadens the choice of species, simplifies cooling, increases available atom number and reduces cycle time for faster integration.

  1. Comparison of the incidence of late stent thrombosis after implantation of different drug-eluting stents in the real world coronary heart disease patients: three-year follow-up results

    Institute of Scientific and Technical Information of China (English)

    CHEN Ji-lin; LIU Hai-bo; WU Yong-jian; YUAN Jin-qing; CHEN Jue; YOU Shi-jie; DAI Jun; GAO Run-lin; GAO Li-jian; YANG Yue-jin; LI Jian-jun; QIAO Shu-bin; XU Bo; HUANG Jing-han; YAO Min; QIN Xue-wen

    2010-01-01

    Background Late stent thrombosis (LST) is still concerned by interventions cardiologists in daily clinical practice. This study aimed to compare the incidence of LST after implantation of different drug-eluting stents (DES) in coronary heart disease (CHD) patients in the real world.Methods From December 2001 to February 2009, a total of 11 875 consecutive CHD patients undergone DES implantation were enrolled in this single-center registery study. Patients with acute ST-segment elevation myocardial infarction, mixed DES implantation, restenosis lesions, and patients who could not take dual antiplatlet medication and those who were contraindicated for coronary interventional treatment were excluded. All patients were treated with completed dual antiplatelet medications for at least 9 months after DES deployment. The follow-up was completed by outpatient visits, letter correspondence, phone calls and coronary angiography. Definite LST was diagnosed auording to the Academic Research Consortium (ARC) definition.Results Cypher or Cypher Select stents were implanted in 4104 cases, Taxus or Taxus Liberty stents in 2271 cases and Firebird stents (Chinese rapamycin-eluting stents) in 5500 cases. One-year follow-up was completed in 9693 patients, including 3346 cases with Cypher or Cypher Select stents, 1529 cases with Taxus or Taxus Liberty stents and 4818 cases with Firebird stents. Two- and three-year follow-up results were obtained in 7133 and 4353 patients, respectively, including 2410 and 1760 cases with Cypher or Cypher Select stents, 1285 and 900 cases with Taxus or Taxus Liberty stents as well as 3438 and 1693 cases with Firebird stents. One-year follow-up results showed that the incidence of LST was 1.08% in patients with Cypher or Cypher Select stents, 1.24% in those with Taxus or Taxus Liberty stents and 0.71% in those with Firebird stents; there was no significant difference between those with Cypher or Cypher Select and Firebird stents, but there was significant

  2. Comparison of recoil-induced resonances and the collective atomic recoil laser

    CERN Document Server

    Berman, P R

    1999-01-01

    The theories of recoil-induced resonances (RIR) [J. Guo, P. R. Berman, B. Dubetsky and G. Grynberg, Phys. Rev. A {\\bf 46}, 1426 (1992)] and the collective atomic recoil laser (CARL) [ R. Bonafacio and L. De Salvo, Nucl. Instrum. Methods A {\\bf 341}, 360 (1994)] are compared. Both theories can be used to derive expressions for the gain experienced by a probe field interacting with an ensemble of two-level atoms that are simultaneously driven by a pump field. It is shown that the RIR and CARL formalisms are equivalent. Differences between the RIR and CARL arise because the theories are typically applied for different ranges of the parameters appearing in the theory. The RIR limit considered in this paper is $qP_{0}/M\\omega_{q}\\gg 1$, while the CARL limit is $qP_{0}/M\\omega_{q}\\lesssim 1$, where $% q $ is the magnitude of the difference of the wave vectors of the pump and probe fields, $P_{0}$ is the width of the atomic momentum distribution and $% \\omega_{q}$ is a recoil frequency. The probe gain for a probe-pu...

  3. 左半结直肠癌急性梗阻采用肠道支架与梗阻导管治疗的临床体会%Clinical Experience of the Treatment of Acute Obstruction of the Left Colon Cancer With the Use of the Intestinal Stent and the Obstruction Catheter

    Institute of Scientific and Technical Information of China (English)

    王新刚; 王光辉

    2015-01-01

    Objective To explore the therapeutic effect of the treatment of acute obstruction of the left colon cancer with the use of the intestinal stent and the obstruction of the catheter. Methods 39 cases with intestinal stents as stent group,39 cases treated by catheter obstruction as catheter group,and the operation effect and the therapeutic effects of two groups were analyzed. Results Two groups of abdominal pain abdominal distension relief time and obstruction of the proximal bowel contrast of inner diameter had difference(P 0.05. Conclusion Compared with the obstruction catheter,metal stent can improve the symptoms of intestinal obstruction in a certain extent.%目的:探究左半结直肠癌急性梗阻采用肠道支架与梗阻导管的疗效。方法39例采用肠道支架治疗作为支架组,39例采用梗阻导管治疗作为导管组,并分析两组的手术治疗效果。结果两组腹痛腹胀缓解时间与梗阻近端肠管内径差值的对比,P <0.05;两组患者术后疗效对比, P >0.05。结论与梗阻导管相比,金属支架能够在某种程度上改善肠梗阻症状。

  4. Delayed complications after flow-diverter stenting: reactive in-stent stenosis and creeping stents.

    Science.gov (United States)

    Cohen, José E; Gomori, John Moshe; Moscovici, Samuel; Leker, Ronen R; Itshayek, Eyal

    2014-07-01

    We assessed the frequency and severity of changes in stent configuration and location after the treatment of intracranial aneurysms, and patterns of in-stent stenosis. We retrospectively reviewed data for consecutive aneurysm patients managed with endovascular implantation of flow-diverter stents (Silk Flow Diverter [Balt Extrusion, Montmorency, France] and Pipeline Embolization Device [ev3/Coviden, Minneapolis, MN, USA]) from October 2011 to July 2012. Routine 2, 6, 9-12, and 16-20 month follow-up angiograms were compared, with a focus on changes in stent configuration and location from immediately after deployment to angiographic follow-up, and the incidence and development of in-stent stenosis. Thirty-four patients with 42 aneurysms met inclusion criteria. The Silk device was implanted in 16 patients (47%, single device in 15), the Pipeline device in 18 (53%, single device in 16). On first follow-up angiography, in-stent stenosis was observed in 38% of Silk devices and 39% of Pipeline devices. In-stent stenosis was asymptomatic in 12 of 13 patients. One woman presented with transient ischemic attacks and required stent angioplasty due to end tapering and mild, diffuse in-stent stenosis. Configuration and location changes, including stent creeping and end tapering were seen in 2/16 patients (13%) with Silk devices, and 0/18 patients with Pipeline devices. We describe stent creeping and end tapering as unusual findings with the potential for delayed clinical complications. In-stent stenosis, with a unique behavior, is a frequent angiographic finding observed after flow-diverter stent implant. The stenosis is usually asymptomatic; however, close clinical and angiographic monitoring is mandatory for individualized management.

  5. Early and long-term outcome of elective stenting of the infarct-related artery in patients with viability in the infarct-area: Rationale and design of the Viability-guided Angioplasty after acute Myocardial Infarction-trial (The VIAMI-trial

    Directory of Open Access Journals (Sweden)

    Visser Cees A

    2004-11-01

    Full Text Available Abstract Background Although percutaneous coronary intervention (PCI is becoming the standard therapy in ST-segment elevation myocardial infarction (STEMI, to date most patients, even in developed countries, are reperfused with intravenous thrombolysis or do not receive a reperfusion therapy at all. In the post-lysis period these patients are at high risk for recurrent ischemic events. Early identification of these patients is mandatory as this subgroup could possibly benefit from an angioplasty of the infarct-related artery. Since viability seems to be related to ischemic adverse events, we initiated a clinical trial to investigate the benefits of PCI with stenting of the infarct-related artery in patients with viability detected early after acute myocardial infarction. Methods The VIAMI-study is designed as a prospective, multicenter, randomized, controlled clinical trial. Patients who are hospitalized with an acute myocardial infarction and who did not have primary or rescue PCI, undergo viability testing by low-dose dobutamine echocardiography (LDDE within 3 days of admission. Consequently, patients with demonstrated viability are randomized to an invasive or conservative strategy. In the invasive strategy patients undergo coronary angiography with the intention to perform PCI with stenting of the infarct-related coronary artery and concomitant use of abciximab. In the conservative group an ischemia-guided approach is adopted (standard optimal care. The primary end point is the composite of death from any cause, reinfarction and unstable angina during a follow-up period of three years. Conclusion The primary objective of the VIAMI-trial is to demonstrate that angioplasty of the infarct-related coronary artery with stenting and concomitant use of abciximab results in a clinically important risk reduction of future cardiac events in patients with viability in the infarct-area, detected early after myocardial infarction.

  6. Metallic stent placement in hemodialysis graft patients after insufficient balloon dilation

    Energy Technology Data Exchange (ETDEWEB)

    Liang, Huei-Lung; Pan, Huay-Ben; Lin, Yih-Huie; Chen, Chiung-Yu; Lai, Pin-Hong; Yang, Chien-Fang [Kaohsiung Veterans General Hospital, Kaohsiung (China); Chung, Hsiao-Min; Wu, Tung-Ho; Chou, Kang-Ju [National Yangming University, Taipei (China)

    2006-06-15

    We wanted to report our experience of metallic stent placement after insufficient balloon dilation in graft hemodialysis patients. Twenty-three patients (13 loop grafts in the forearm and 10 straight grafts in the upper arm) underwent metallic stent placement due to insufficient flow after urokinase thrombolysis and balloon dilation. The indications for metallic stent deployment included 1) recoil and/or kinked venous stenosis in 21 patents (venous anastomosis: 17 patients, peripheral outflow vein: four patients); and 2) major vascular rupture in two patients. Metallic stents 8-10mm in diameter and 40-80 mm in length were used. Of them, eight stents were deployed across the elbow crease. Access patency was determined by clinical follow-up and the overall rates were calculated by Kaplan-Meier survival analysis. No procedure-related complications (stent fracture or central migration) were encountered except for a delayed Wallstent shortening/migration at the venous anastomosis, which resulted in early access failure. The overall primary and secondary patency rates ({+-}standard error) of all the vascular accesses in our 23 patients at 3, 6, 12 and 24 months were 69%{+-}9 and 88%{+-}6,41% {+-}10 and 88%{+-}6, 30%{+-}10 and 77%{+-}10, and 12%{+-}8 and 61%{+-}13, respectively. For the forearm and upper-arm grafts, the primary and secondary patency rates were 51%{+-}16 and 86%{+-}13 vs 45%{+-}15 and 73%{+-}13 at 6 months, and 25%{+-}15 and 71%{+-}17 vs 23%{+-}17 and 73%{+-}13 at 12 months ({rho} = .436 and .224), respectively. Metallic stent placement is a safe and effective means for treating peripheral venous lesions in dialysis graft patients after insufficient balloon dilation. No statistically difference in the patency rates between the forearm and upper-arm patient groups was seen.

  7. 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 ...

  8. Two-Photon Collective Atomic Recoil Lasing

    Directory of Open Access Journals (Sweden)

    James A. McKelvie

    2015-11-01

    Full Text Available We present a theoretical study of the interaction between light and a cold gasof three-level, ladder configuration atoms close to two-photon resonance. In particular, weinvestigate the existence of collective atomic recoil lasing (CARL instabilities in differentregimes of internal atomic excitation and compare to previous studies of the CARL instabilityinvolving two-level atoms. In the case of two-level atoms, the CARL instability is quenchedat high pump rates with significant atomic excitation by saturation of the (one-photoncoherence, which produces the optical forces responsible for the instability and rapid heatingdue to high spontaneous emission rates. We show that in the two-photon CARL schemestudied here involving three-level atoms, CARL instabilities can survive at high pump rateswhen the atoms have significant excitation, due to the contributions to the optical forces frommultiple coherences and the reduction of spontaneous emission due to transitions betweenthe populated states being dipole forbidden. This two-photon CARL scheme may form thebasis of methods to increase the effective nonlinear optical response of cold atomic gases.

  9. Direct Measurement of Photon Recoil from a Levitated Nanoparticle

    CERN Document Server

    Jain, Vijay; Moritz, Clemens; Dellago, Christoph; Quidant, Romain; Novotny, Lukas

    2016-01-01

    The momentum transfer between a photon and an object defines a fundamental limit for the precision with which the object can be measured. If the object oscillates at a frequency $\\Omega_0$, this measurement back-action adds quanta $\\hbar\\Omega_0$ to the oscillator's energy at a rate $\\Gamma_{\\rm recoil}$, a process called photon recoil heating, and sets bounds to quantum coherence times in cavity optomechanical systems. Here, we use an optically levitated nanoparticle in ultrahigh vacuum to directly measure $\\Gamma_{\\rm recoil}$. By means of a phase-sensitive feedback scheme, we cool the harmonic motion of the nanoparticle from ambient to micro-Kelvin temperatures and measure its reheating rate under the influence of the radiation field. The recoil heating rate is measured for different particle sizes and for different excitation powers, without the need for cavity optics or cryogenic environments. The measurements are in quantitative agreement with theoretical predictions and provide valuable guidance for th...

  10. The median recoil direction as a WIMP directional detection signal

    CERN Document Server

    Green, Anne M

    2010-01-01

    Direct detection experiments have reached the sensitivity required to detect dark matter WIMPs. Demonstrating that a putative signal is due to WIMPs, and not backgrounds, is a major challenge however. The direction dependence of the WIMP scattering rate provides a potential WIMP `smoking gun'. If the WIMP distribution is predominantly smooth, the Galactic recoil distribution is peaked in the direction opposite to the direction of Solar motion. Previous studies have found that, for an ideal detector, of order 10 WIMP events would be sufficient to reject isotropy, and rule out an isotropic background. We examine how the median recoil direction could be used to confirm the WIMP origin of an anisotropic recoil signal. Specifically we determine the number of events required to reject the null hypothesis that the median direction is random (corresponding to an isotropic Galactic recoil distribution) at 95% confidence. We find that for zero background 31 events are required, a factor of roughly 2 more than are requi...

  11. Nasal packing and stenting

    Directory of Open Access Journals (Sweden)

    Weber, Rainer K.

    2009-01-01

    Full Text Available Nasal packs are indispensable in ENT practice. This study reviews current indications, effectiveness and risks of nasal packs and stents. In endoscopic surgery, nasal packs should always have smooth surfaces to minimize mucosal damage, improve wound healing and increase patient comfort. Functional endoscopic endonasal sinus surgery allows the use of modern nasal packs, since pressure is no longer required. So called hemostatic/resorbable materials are a first step in this direction. However, they may lead to adhesions and foreign body reactions in mucosal membranes. Simple occlusion is an effective method for creating a moist milieu for improved wound healing and avoiding dryness. Stenting of the frontal sinus is recommended if surgery fails to produce a wide, physiologically shaped drainage path that is sufficiently covered by intact tissue.

  12. Rational minimally invasive treatment of pAOD: when should a conservative approach, PTA, or stent be chosen?; Rationale minimal-invasive Therapie der pAVK: wann konservativ, wann PTA, wann Stent

    Energy Technology Data Exchange (ETDEWEB)

    Mueller-Huelsbeck, S. [Universitaetsklinikum Schleswig-Holstein der Christian-Albrechts-Universitaet zu Kiel, Klinik fuer Diagnostische Radiologie, Kiel (Germany)

    2006-11-15

    In order to obtain optimal results and satisfied patients, rational therapy of pAOD should strictly follow national and international society guidelines. In particular cases an individual therapeutic concept seems justified beyond these guidelines. Based on clinical data and driven by costs, aortic and iliac lesions may be treated by PTA or selective stent placement with equal results; however, long-term data justify also primary, direct stenting. For treatment of infrainguinal and popliteal stenotic lesions primary stenting should be restricted to PTA failure (dissection, recoil, occlusion); except for treatment of extended lesions, primary stenting compared to PTA alone seems beneficial in terms of midterm patency. Endovascular procedures below the knee and at the toe should be limited to existing limb-threatening ischemia in order to save the extremity; whether PTA or stenting is advantageous has not yet determined. (orig.) [German] Die rationale Therapie der peripheren arteriellen Verschlusskrankheit (pAVK) sollte in Anlehnung an Richtlinien der nationalen und internationalen Fachgesellschaften erfolgen, um in hohem Masse ein klinisch optimales und zufrieden stellendes Behandlungsergebnis fuer den Patienten zu erreichen. Im Einzelfall muss allerdings eine individuelle Therapiestrategie ausserhalb der Richtlinien entwickelt werden. Basierend auf gleichwertigen klinischen Daten und Kostengruenden sind aortal und in besonderem Masse iliakal die alleinige perkutane transluminale Angioplastie (PTA) und/oder selektive Stentimplantation zu bevorzugen, wenngleich ausgezeichnete Langzeitergebnisse auch eine direkte, primaere Stentimplantation rechtfertigen. Infrainguinal und popliteal hingegen sollten Stents nicht primaer zur Behandlung stenosierender Veraenderungen eingesetzt werden, sondern nur nach fehlgeschlagener PTA (Dissektion, Recoil, Verschluss); lediglich zur Behandlung langstreckiger Veraenderungen koennte eine Stentimplantation Vorteile gegenueber einer

  13. Role of self expandable stents in management of colorectalcancers

    Institute of Scientific and Technical Information of China (English)

    2016-01-01

    Acute malignant colorectal obstruction is a complicationof colorectal cancer that can occur in 7%-29% of patients. Self-expanding metallic stent placement formalignant colorectal obstruction has gained popularity asa safe and effective procedure for relieving obstruction.This technique can be used in the palliation of malignantcolorectal obstruction, as a bridge to elective surgery forresectable colorectal cancers, palliation of extracolonicmalignant obstruction, and for nonmalignant etiologiessuch as anastomotic strictures, Crohn's disease, radiationtherapy, and diverticular diseases. Self-expandingmetallic stent has its own advantages and disadvantagesover the surgery in these indications. During the insertionof the self-expanding metallic stent, and in the followup,short term and long term morbidities should be keptin mind. The most important complications of the stentsare perforation, stent obstruction, stent migration, andbleeding. Additionally, given the high risk of perforation,if a patient is treated or being consideredfortreatmentwithantiangiogenic agents such as bevacizumab, it isnot recommended to use self-expanding metallic stentas a palliative treatment for obstruction. Therefore, thereis a need for careful clinical evaluation for each patientwho is a candidate for this procedure. The purpose ofthis review was to evaluate self-expanding metallic stentin the management of the obstruction of the colon dueto the colorectal and extracolonic obstruction.

  14. Metallic Stents for Proximal Tracheal Stenosis: Is It Worth the Risk?

    Directory of Open Access Journals (Sweden)

    Sandeep Bansal

    2012-01-01

    Full Text Available Objective. To demonstrate the risk associated with blocked proximal tracheal stents when a patient presents with acute respiratory distress, with blockage of stent and what is the best management we can offer without damage to the stent and its associated complications. Case Report. A 22-yr-old, male patient, presented in severe respiratory distress. He had history of corrosive poisoning for which he was tracheotomised. A stainless steel wire mesh stent was placed in the trachea, from the subglottis, to just above the carina. One month later, he presented with a critically compromised airway with severe respiratory distress. Emergency tracheostomy was done and the metallic stent had to be cut open, in order to provide an airway. Conclusion. Management of blocked proximal stents with patient in respiratory distress remains a challenge. Formation of granulation tissue is common and fibreoptic bronchoscopic assisted intubation may not always be possible. A regular follow up of all patients with stents is essential. Placement of stents within a few centimetres of cricotracheal junction should not be encouraged for long term indications.

  15. Dynamic Simulation of the Tank Gun Recoil Response

    Institute of Scientific and Technical Information of China (English)

    XING Jun-wen; WANG Liang-xi; SHI Yan; CHEN Chun-liang

    2005-01-01

    By using the ATV module of MSC. ADAMS, the dynamic simulation of recoil response of tank gun is analyzed.How the recoil force affects the bodywork and the suspension during gun firing, as well as the changing status of the gun muzzle's velocity are gained. All results and analyzing methods are offered for the designing basis of optimizing tank vehicle-gun match. The constructive exploration is beneficial to improving the general capability of tank.

  16. Carotid artery stenting: which stent for which lesion?

    Science.gov (United States)

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

    2005-01-01

    The different geometries and working principles of carotid stents (nitinol or cobalt chromium, open- or closed-cell configuration) provide each product with unique functional properties. The individual characteristics of each device may make it an attractive choice in one circumstance but render it less desirable in other situations. In approximately 75% of all procedures, all types of stents will achieve similar outcomes, making adequate device selection unnecessary. For the remaining quarter, careful preoperative screening is mandatory. In addition to eventual access issues, the choice of the optimal carotid stent depends mainly on arterial anatomy and lesion morphology. When treating a tortuous anatomy, stents with a flexible and comformable open-cell configuration are preferred. In arteries with a significant mismatch between common carotid artery and internal carotid artery diameter, cobalt chromium (Elgiloy) or tapered nitinol stents are selected. Lesions with suspected high emboligenicity are best covered with stents with a closed-cell configuration, whereas highly calcified lesions need treatment with nitinol stents. Thorough knowledge of the characteristics, advantages and disadvantages, and working principles of the different available stents is mandatory to optimally select the materials to be used for patients eligible for carotid revascularization.

  17. Hemodynamics in Idealized Stented Coronary Arteries: Important Stent Design Considerations.

    Science.gov (United States)

    Beier, Susann; Ormiston, John; Webster, Mark; Cater, John; Norris, Stuart; Medrano-Gracia, Pau; Young, Alistair; Cowan, Brett

    2016-02-01

    Stent induced hemodynamic changes in the coronary arteries are associated with higher risk of adverse clinical outcome. The purpose of this study was to evaluate the impact of stent design on wall shear stress (WSS), time average WSS, and WSS gradient (WSSG), in idealized stent geometries using computational fluid dynamics. Strut spacing, thickness, luminal protrusion, and malapposition were systematically investigated and a comparison made between two commercially available stents (Omega and Biomatrix). Narrower strut spacing led to larger areas of adverse low WSS and high WSSG but these effects were mitigated when strut size was reduced, particularly for WSSG. Local hemodynamics worsened with luminal protrusion of the stent and with stent malapposition, adverse high WSS and WSSG were identified around peak flow and throughout the cardiac cycle respectively. For the Biomatrix stent, the adverse effect of thicker struts was mitigated by greater strut spacing, radial cell offset and flow-aligned struts. In conclusion, adverse hemodynamic effects of specific design features (such as strut size and narrow spacing) can be mitigated when combined with other hemodynamically beneficial design features but increased luminal protrusion can worsen the stent's hemodynamic profile significantly.

  18. Percutaneous Placement of Permanent Metallic Stents in the Cystic Duct to Treat Obstructive Cholecystitis.

    Science.gov (United States)

    Brown, Nicholas I; Jhamb, Ashu; Brooks, Duncan M; Little, Andrew F

    2015-12-01

    This report presents a series of five patients unsuitable for surgery who had nonretrievable self-expanding metallic stents deployed along the cystic duct as treatment for benign and malignant causes of gallbladder obstruction. Techniques are described for draining cholecystitis, removing gallstones, bypassing gallbladder obstructions, and inserting metallic stents across the cystic duct to restore permanent antegrade gallbladder drainage in acute and chronic cholecystitis. Symptoms resolved in all cases, and stents remained patent for as long as 22 months. This procedure may be an effective alternative to cholecystectomy or long-term gallbladder drainage for patients in inoperable condition.

  19. Stent Thrombosis Patients with Hyporesponsiveness to Clopidogrel, Prasugrel, and Ticagrelor: A Case Series Using Short Thromboelastography

    Directory of Open Access Journals (Sweden)

    Bartosz Olechowski

    2016-01-01

    Full Text Available Patients after percutaneous coronary intervention (PCI with stent implantation and functional hyporesponsiveness to P2Y12 inhibitors are at higher risk of ischaemic events, particularly stent thrombosis (ST. It is currently not routine practice to assess the functional response to these agents. However, concern over functional hyporesponsiveness to clopidogrel has led to widespread uptake of prasugrel and ticagrelor as the default P2Y12 inhibitor after stent implantation in patients with acute coronary syndrome. Here we report, for the first time, 3 cases in which patients who have had ST exhibit hyporesponsiveness to clopidogrel, prasugrel, and ticagrelor.

  20. Delayed aortic regurgitation caused by a right coronary stent protruding into the aorta.

    Science.gov (United States)

    Quintana, Eduard; Mestres, Carlos A; Congiu, Stefano; Josa, Miguel; Cartañá, Ramon

    2009-11-01

    Aortic valve perforation is an extremely rare complication after percutaneous coronary intervention. The case is presented of a 49-year-old male with aortic valve regurgitation secondary to the intra-aortic protrusion of a right coronary stent. The patient had undergone an apparently successful rescue percutaneous transluminal coronary angioplasty with a drug-eluting stent following failed fibrinolysis, but one month later was readmitted for acute pulmonary edema. Further investigations demonstrated new-onset aortic regurgitation. Medical stabilization was achieved and an elective aortic valve replacement and coronary revascularization performed. Intraoperatively, the stent was found to be partially deployed within the aortic lumen, causing perforation to the non-coronary cusp.

  1. The recoiling of liquid droplets upon collision with solid surfaces

    Science.gov (United States)

    Kim, H.-Y.; Chun, J.-H.

    2001-03-01

    Although the spreading behavior of liquid droplets impacting on solid surfaces has been extensively studied, the mechanism of recoiling which takes place after the droplet reaches its maximum spread diameter has not yet been fully understood. This paper reports the study of the recoiling behavior of different liquid droplets (water, ink, and silicone oil) on different solid surfaces (polycarbonate and silicon oxide). The droplet dynamics are experimentally studied using a high speed video system. Analytical methods using the variational principle, which were originated by Kendall and Rohsenow (MIT Technical Report 85694-100, 1978) and Bechtel et al. [IBM J. Res. Dev. 25, 963 (1981)], are modified to account for wetting and viscous effects. In our model, an empirically determined dissipation factor is used to estimate the viscous friction. It is shown that the model closely predicts the experimental results obtained for the varying dynamic impact conditions and wetting characteristics. This study shows that droplets recoil fast and vigorously when the Ohnesorge number decreases or the Weber number increases. Droplets with a large equilibrium contact angle are also found to recoil faster. Here the Ohnesorge number scales the resisting force to the recoiling motion, and is shown to play the most important role in characterizing the recoiling motion.

  2. Stents for malignant ureteral obstruction

    Directory of Open Access Journals (Sweden)

    Kristina Pavlovic

    2016-07-01

    Full Text Available Malignant ureteral obstruction can result in renal dysfunction or urosepsis and can limit the physician's ability to treat the underlying cancer. There are multiple methods to deal with ureteral obstruction including regular polymeric double J stents (DJS, tandem DJS, nephrostomy tubes, and then more specialized products such as solid metal stents (e.g., Resonance Stent, Cook Medical and polyurethane stents reinforced with nickel-titanium (e.g., UVENTA stents, TaeWoong Medical. In patients who require long-term stenting, a nephrostomy tube could be transformed subcutaneously into an extra-anatomic stent that is then inserted into the bladder subcutaneously. We outline the most recent developments published since 2012 and report on identifiable risk factors that predict for failure of urinary drainage. These failures are typically a sign of cancer progression and the natural history of the disease rather than the individual type of drainage device. Factors that were identified to predict drainage failure included low serum albumin, bilateral hydronephrosis, elevated C-reactive protein, and the presence of pleural effusion. Head-to-head studies show that metal stents are superior to polymeric DJS in terms of maintaining patency. Discussions with the patient should take into consideration the frequency that exchanges will be needed, the need for externalized hardware (with nephrostomy tubes, or severe urinary symptoms in the case of internal DJS. This review will highlight the current state of diversions in the setting of malignant ureteral obstruction.

  3. Stenting of the Cystic Duct in Benign Disease: A Definitive Treatment for the Elderly and Unwell

    Energy Technology Data Exchange (ETDEWEB)

    Hersey, N., E-mail: naomi.hersey@sth.nhs.uk [Sheffield Teaching Hospitals NHS Trust, Department of Radiology, Northern General Hospital (United Kingdom); Goode, S. D., E-mail: s.goode@sheffield.sc.uk [Sheffield Teaching Hospitals NHS Trust, Sheffield Vascular Institute (United Kingdom); Peck, R. J., E-mail: robert.peck@sth.nhs.uk; Lee, F., E-mail: fred.lee@sth.nhs.uk [Sheffield Teaching Hospitals NHS Trust, Department of Radiology, Northern General Hospital (United Kingdom)

    2015-08-15

    PurposeThere have been few case reports describing cystic duct stent insertion in the management of acute cholecystitis secondary to benign disease with no case series published to date. We present our series demonstrating the role of cystic duct stents in managing benign gallbladder disease in those patients unfit for surgery.Materials and MethodsThirty three patients unfit for surgery in our institution underwent cystic duct stent insertion for the management of acute cholecystitis in the period June 2008 to June 2013. Patients underwent a mixture of transperitoneal and transhepatic gallbladder puncture. The cystic duct was cannulated with a hydrophilic guidewire which was subsequently passed through the common bile duct and into the duodenum. An 8Fr 12-cm double-pigtail stent was placed with the distal end lying within the duodenum and the proximal end within the gallbladder.ResultsTen patients presented with gallbladder perforation, 21 patients with acute cholecystitis, 1 with acute cholangitis and 1 with necrotising pancreatitis. The technical success rate was 91 %. We experienced a 13 % complication rate with 3 % mortality rate at 30 days.ConclusionCystic duct stent insertion can be successfully used to manage acute cholecystitis, gallbladder empyema or gallbladder perforations in those unfit for surgery and should be considered alongside external gallbladder drainage as a definitive mid-term treatment option.

  4. Incidence of definite stent thrombosis or in-stent restenosis after drug-eluting stent implantation for treatment of coronary in-stent restenosis

    DEFF Research Database (Denmark)

    Jensen, Jesper Khedri; Jensen, Lisette Okkels; Terkelsen, Christian Juhl;

    2013-01-01

    There are limited data on the optimal management of in-stent restenosis after percutaneous coronary intervention (PCI) with bare metal stent (BMS) or drug-eluting stent (DES) implantations. We assessed the clinical presentation, the incidence, and prognosis of definite stent thrombosis...

  5. [Longitudinal stent deformation during bifurcation lesion treatment].

    Science.gov (United States)

    Mami, Z; Monsegu, J

    2014-12-01

    Longitudinal stent deformation is defined as a compression of stent length after its implantation. It's a rare complication but dangerous seen with several stents. We reported a case of longitudinal stent deformation during bifurcation lesion treatment with a Promus Element(®) and we perform a short review of this complication.

  6. Double-barrel Y-configuration stenting for flow diversion of a giant recurrent basilar apex aneurysm with the pipeline flex embolization device

    Directory of Open Access Journals (Sweden)

    Dale Ding

    2016-01-01

    Full Text Available Giant basilar apex aneurysms are extremely challenging to successfully manage. The Pipeline Flex embolization device (PFED is a new generation flow-diverting stent with a modified delivery system which allows resheathing of the stent after partial deployment. We describe a case of double-barrel Y-configuration stenting of a giant, recurrent basilar apex aneurysm using the PFED. A 73-year-old male was previously treated for an unruptured 11-mm basilar apex aneurysm with stent-assisted coiling using a Neuroform stent. The aneurysm was retreated twice with repeat coiling. After the third recurrence and persistent aneurysm growth into a giant, symptomatic lesion, we decided to proceed with flow diversion. We performed Y-stenting of the basilar bifurcation using three PFEDs, and was recoiled the aneurysm sac. Due to the low porosity of the flow diverters, a side-by-side double-barrel configuration was necessary in the basilar artery. Without the PFED's resheathable capability, it would not have been possible to perform Y-stenting with flow diverters.

  7. Double-barrel Y-configuration Stenting for Flow Diversion of a Giant Recurrent Basilar Apex Aneurysm with the Pipeline Flex Embolization Device.

    Science.gov (United States)

    Ding, Dale; Starke, Robert M; McGuinness, Ben; Brew, Stefan

    2016-12-01

    Giant basilar apex aneurysms are extremely challenging to successfully manage. The Pipeline Flex embolization device (PFED) is a new generation flow-diverting stent with a modified delivery system which allows resheathing of the stent after partial deployment. We describe a case of double-barrel Y-configuration stenting of a giant, recurrent basilar apex aneurysm using the PFED. A 73-year-old male was previously treated for an unruptured 11-mm basilar apex aneurysm with stent-assisted coiling using a Neuroform stent. The aneurysm was retreated twice with repeat coiling. After the third recurrence and persistent aneurysm growth into a giant, symptomatic lesion, we decided to proceed with flow diversion. We performed Y-stenting of the basilar bifurcation using three PFEDs, and was recoiled the aneurysm sac. Due to the low porosity of the flow diverters, a side-by-side double-barrel configuration was necessary in the basilar artery. Without the PFED's resheathable capability, it would not have been possible to perform Y-stenting with flow diverters.

  8. Efficacy of multiple biliary stenting for refractory benign biliary strictures due to chronic calcifying pancreatitis

    Science.gov (United States)

    Ohyama, Hiroshi; Mikata, Rintaro; Ishihara, Takeshi; Sakai, Yuji; Sugiyama, Harutoshi; Yasui, Shin; Tsuyuguchi, Toshio

    2017-01-01

    AIM To investigate endoscopic therapy efficacy for refractory benign biliary strictures (BBS) with multiple biliary stenting and clarify predictors. METHODS Ten consecutive patients with stones in the pancreatic head and BBS due to chronic pancreatitis who underwent endoscopic therapy were evaluated. Endoscopic insertion of a single stent failed in all patients. We used plastic stents (7F, 8.5F, and 10F) and increased stents at intervals of 2 or 3 mo. Stents were removed approximately 1 year after initial stenting. BBS and common bile duct (CBD) diameter were evaluated using cholangiography. Patients were followed for ≥ 6 mo after therapy, interviewed for cholestasis symptoms, and underwent liver function testing every visit. Patients with complete and incomplete stricture dilations were compared. RESULTS Endoscopic therapy was completed in 8 (80%) patients, whereas 2 (20%) patients could not continue therapy because of severe acute cholangitis and abdominal abscess, respectively. The mean number of stents was 4.1 ± 1.2. In two (20%) patients, BBS did not improve; thus, a biliary stent was inserted. BBS improved in six (60%) patients. CBD diameter improved more significantly in the complete group than in the incomplete group (6.1 ± 1.8 mm vs 13.7 ± 2.2 mm, respectively, P = 0.010). Stricture length was significantly associated with complete stricture dilation (complete group; 20.5 ± 3.0 mm, incomplete group; 29.0 ± 5.1 mm, P = 0.011). Acute cholangitis did not recur during the mean follow-up period of 20.6 ± 7.3 mo. CONCLUSION Sequential endoscopic insertion of multiple stents is effective for refractory BBS caused by chronic calcifying pancreatitis. BBS length calculation can improve patient selection procedure for therapy. PMID:28101303

  9. Safety and efficacy of everolimus-eluting stents compared with first-generation drug-eluting stents in patients undergoing primary percutaneous coronary intervention

    Energy Technology Data Exchange (ETDEWEB)

    Escárcega, Ricardo O.; Baker, Nevin C.; Magalhaes, Marco A.; Lipinski, Michael J.; Minha, Sa’ar; Torguson, Rebecca; Satler, Lowell F.; Pichard, Augusto D.; Suddath, William O.; Waksman, Ron, E-mail: ron.waksman@medstar.net

    2014-09-15

    Objective: To assess the safety and efficacy everolimus-eluting stents (EES) compared with first-generation drug-eluting stents (DES) in patients with acute myocardial infarction (MI) undergoing primary percutaneous coronary intervention (PCI). Background: EES have been associated with improved clinical outcomes compared to paclitaxel-eluting stents (PES) and with similar outcomes compared to sirolimus-eluting stents (SES). Methods: A total of 520 patients who presented with ST-elevation myocardial infarction (STEMI) from 2003 to 2013, who underwent primary PCI with DES, were retrospectively analyzed. Of these, 247 received SES, 136 PES, and 137 EES. Patients were followed up to 2 years for major adverse cardiac events (MACE). Univariate and multivariate models detected correlates to outcome. Results: EES implantation, compared with PES and SES, resulted in comparable rates of MACE (8.8% vs. 16.2%, p = 0.06 and 8.8% vs. 12.6%, respectively, p = 0.26), stent thrombosis, MI, and target lesion revascularization. Patients who received EES had lower rates of all-cause mortality (3.7% vs. 12.6% vs. 9.4%, p = 0.03) at 1-year follow up. However, in the univariate and multivariate analyses, stent type was not independently associated with the primary outcome or with all-cause mortality. Diabetes mellitus and number of stents implanted were independently associated with the primary outcome. Conclusion: While EES seem to be associated with better outcome when compared to PES, the main correlates of STEMI patients are the presence of diabetes and number of stents implanted, and not the type of stent used for intervention.

  10. Trans-Stent B-Mode Ultrasound and Passive Cavitation Imaging.

    Science.gov (United States)

    Haworth, Kevin J; Raymond, Jason L; Radhakrishnan, Kirthi; Moody, Melanie R; Huang, Shao-Ling; Peng, Tao; Shekhar, Himanshu; Klegerman, Melvin E; Kim, Hyunggun; McPherson, David D; Holland, Christy K

    2016-02-01

    Angioplasty and stenting of a stenosed artery enable acute restoration of blood flow. However, restenosis or a lack of re-endothelization can subsequently occur depending on the stent type. Cavitation-mediated drug delivery is a potential therapy for these conditions, but requires that particular types of cavitation be induced by ultrasound insonation. Because of the heterogeneity of tissue and stochastic nature of cavitation, feedback mechanisms are needed to determine whether the sustained bubble activity is induced. The objective of this study was to determine the feasibility of passive cavitation imaging through a metal stent in a flow phantom and an animal model. In this study, an endovascular stent was deployed in a flow phantom and in porcine femoral arteries. Fluorophore-labeled echogenic liposomes, a theragnostic ultrasound contrast agent, were injected proximal to the stent. Cavitation images were obtained by passively recording and beamforming the acoustic emissions from echogenic liposomes insonified with a low-frequency (500 kHz) transducer. In vitro experiments revealed that the signal-to-noise ratio for detecting stable cavitation activity through the stent was greater than 8 dB. The stent did not significantly reduce the signal-to-noise ratio. Trans-stent cavitation activity was also detected in vivo via passive cavitation imaging when echogenic liposomes were insonified by the 500-kHz transducer. When stable cavitation was detected, delivery of the fluorophore into the arterial wall was observed. Increased echogenicity within the stent was also observed when echogenic liposomes were administered. Thus, both B-mode ultrasound imaging and cavitation imaging are feasible in the presence of an endovascular stent in vivo. Demonstration of this capability supports future studies to monitor restenosis with contrast-enhanced ultrasound and pursue image-guided ultrasound-mediated drug delivery to inhibit restenosis.

  11. Cardiomiopatia isquêmica terminal associada à complicação do uso de stent no tratamento de infarto agudo do miocárdio Terminal ischemic cardiomyopathy associated with complication of stenting in the treatment of acute myocardial infarction

    Directory of Open Access Journals (Sweden)

    Renato Braulio

    2011-09-01

    Full Text Available Uma complicação grave, como a dissecção do tronco de coronária esquerda, com redução relevante do fluxo sanguíneo coronário pela luz verdadeira, requer ação rápida. Diante disso, a escolha imediata do stent no comprimento e calibre adequados para tratar a complicação se faz necessária.A serious complication such as dissection of the left main coronary artery, with significant reduction in coronary blood flow by the true light, requires quick action. Therefore, the immediate choice of stent with appropriate length and size to treat the complication is necessary.

  12. Energy acceptance of the St. George recoil separator

    Science.gov (United States)

    Meisel, Z.; Moran, M. T.; Gilardy, G.; Schmitt, J.; Seymour, C.; Couder, M.

    2017-04-01

    Radiative alpha-capture, (α , γ) , reactions play a critical role in nucleosynthesis and nuclear energy generation in a variety of astrophysical environments. The St. George recoil separator at the University of Notre Dame's Nuclear Science Laboratory was developed to measure (α , γ) reactions in inverse kinematics via recoil detection in order to obtain nuclear reaction cross sections at the low energies of astrophysical interest, while avoiding the γ-background that plagues traditional measurement techniques. Due to the γ ray produced by the nuclear reaction at the target location, recoil nuclei are produced with a variety of energies and angles, all of which must be accepted by St. George in order to accurately determine the reaction cross section. We demonstrate the energy acceptance of the St. George recoil separator using primary beams of helium, hydrogen, neon, and oxygen, spanning the magnetic and electric rigidity phase space populated by recoils of anticipated (α , γ) reaction measurements. We find the performance of St. George meets the design specifications, demonstrating its suitability for (α , γ) reaction measurements of astrophysical interest.

  13. Present and future of endovascular SFA treatment: stents, stent-grafts, drug coated balloons and drug coated stents.

    Science.gov (United States)

    Bosiers, M; Deloose, K; Verbist, J; Peeters, P

    2008-04-01

    The current evolution towards treating more complex femoropopliteal lesions as seen in the renewed TASC II recommendations clearly reflects the continuous evolutions in femoropopliteal stent design. Recent stent design improvements focus on decreasing stent fractures rates which can negatively impact patency rates. By rearranging strut alignment towards helical connecting bridges or full helical stent designs, stent designers have successfully improved the fracture resistance of their stents. The superior fracture resistance of the latest stent generation in combination with the production of long nitinol stents of up to 20 cm in length allow that more difficult and complex lesions can be treated endovascularly. The continuous perfection of nitinol stent platforms followed by the transfer of coronary technologies (e.g. active coatings) towards peripheral devices might broaden the indications for the minimal invasive strategy towards TransAtlantic Inter-Society Consensus (TASC) II C&D lesions.

  14. 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.

  15. Accounting for Recoil Effects in Geochronometers: A New Model Approach

    Science.gov (United States)

    Lee, V. E.; Huber, C.

    2012-12-01

    A number of geologically important chronometers are affected by, or owe their utility to, the "recoil effect". This effect describes the physical displacement of a nuclide due to energetic nuclear processes such as radioactive alpha decay (as in the case of various parent-daughter pairs in the uranium-series decay chains, and Sm-Nd), as well as neutron irradiation (in the case of the methodology for the 40Ar/39Ar dating method). The broad range of affected geochronometers means that the recoil effect can impact a wide range of dating method applications in the geosciences, including but not limited to: Earth surface processes, paleoclimate, volcanic processes, and cosmochemistry and planetary evolution. In particular, the recoil effect can have a notable impact on the use of fine grains (silt- and clay-sized particles) for geochronometric dating purposes. This is because recoil-induced loss of a nuclide from the surfaces of a grain can create an isotopically-depleted outer rind, and for small grains, this depleted rind can be volumetrically significant. When this recoil loss is measurable and occurs in a known time-dependent fashion, it can usefully serve as the basis for chronometers (such as the U-series comminution age method); in other cases recoil loss from fine particles creates an unwanted deviation from expected isotope values (such as for the Ar-Ar method). To improve both the accuracy and precision of ages inferred from geochronometric systems that involve the recoil of a key nuclide from small domains, it is necessary to quantify the magnitude of the recoil loss of that particular nuclide. It is also necessary to quantitatively describe the effect of geological processes that can alter the outer surface of grains, and hence the isotopically-depleted rind. Here we present a new mathematical and numerical model that includes two main features that enable enhanced accuracy and precision of ages determined from geochronometers. Since the surface area of the

  16. Angular distributions of very low energy recoil ions

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez Lepera, C.E.; Breinig, M.; Burgdoerfer, J.; DeSerio, R.; Elston, S.B.; Gibbons, J.P.; Huelskoetter, H.P.; Liljeby, L.; Vane, C.R.; Sellin, I.A.

    1986-01-01

    We present the first measurements of the angular distribution of recoil ions near 90/sup 0/ with respect to the incident projectile direction. Beams of 22.5 and 33 MeV chlorine ions (incident charge states q =4,5,8) have been used as ''hammer'' beams incident on Ne atoms. We confirm the long standing assumption that these recoil ions are ejected preferentially at angles near 90/sup 0/ with respect to the primary beam direction and with energies typically less than 5 eV. Recoil ions ejected around 90/sup 0/ have an energy distribution appreciably wider than those ejected at either larger or smaller angles. 9 refs., 6 figs.

  17. Low momentum recoil detectors in CLAS12 at Jefferson Lab

    Science.gov (United States)

    Charles, Gabriel; CLAS Collaboration Collaboration

    2017-01-01

    Part of the experimental program in Hall B of the Jefferson Lab is dedicated to studying nucleon structure using DIS on nuclei and detecting low-momentum recoil particles in coincidence with the scattered electron. For this purpose, specially designed central detectors are required in place of the inner tracker of CLAS12 to detect particles with momenta below 100 MeV/c. We will present the status of the BONuS12 RTPC detector that will take data within the next 2 years. We will detail the main improvements made from the previous BONuS RTPC. In a second part, we will discuss another recoil experiment, called ALERT, that has been proposed to run in Hall B. The constraints being different, the recoil detector is based on a drift chamber and an array of scintillators. We will present the main differences between the two detectors and summarize the R&D performed to develop the ALERT detector.

  18. First detection of tracks of radon progeny recoils by MIMAC

    CERN Document Server

    Riffard, Q; Bosson, G; Bourrion, O; Descombes, T; Fourel, C; Guillaudin, O; Muraz, J -F; Colas, P; Ferrer-Ribas, E; Giomataris, I; Busto, J; Fouchez, D; Tao, C; Lebreton, L; Maire, D

    2015-01-01

    The MIMAC experiment is a $\\mu$-TPC matrix project for directional dark matter search. Directional detection is a strategy based on the measurement of the WIMP flux anisotropy due to the solar system motion with respect to the dark matter halo. The main purpose of MIMAC project is the measurement of the energy and the direction of nuclear recoils in 3D produced by elastic scattering of WIMPs. Since June 2012 a bi-chamber prototype is operating at the Modane underground laboratory. In this paper, we report the first ionization energy and 3D track observations of nuclear recoils produced by the radon progeny. This measurement shows the capability of the MIMAC detector and opens the possibility to explore the low energy recoil directionality signature.

  19. Powerful flares from recoiling black holes in quasars

    CERN Document Server

    Shields, G A

    2008-01-01

    Mergers of spinning black holes can give recoil velocities from gravitational radiation up to several thousand km/s. A recoiling supermassive black hole in an AGN retains the inner part of its accretion disk. Marginally bound material rejoining the disk around the moving black hole releases a large amount of energy in shocks in a short time, leading to a flare in thermal soft X-rays with a luminosity approaching the Eddington limit. Reprocessing of the X-rays by the infalling material gives strong optical and ultraviolet emission lines with a distinctive spectrum. Despite the short lifetime of the flare (~10^4 yr), as many as 100 flares may be in play at the present time in QSOs at redshifts ~ 1 to 3. These flares provide a means to identify high velocity recoils.

  20. Electric charge spectrum of recoiling {sup 218}Po

    Energy Technology Data Exchange (ETDEWEB)

    Abou-Khalil, R. [Institut de Radioprotection et de Surete Nucleaire (IRSN)/Service d' Etudes et de Recherches en Aerodispersion des polluants et en Confinement, B.P 68, 91192 Gif-sur-Yvette Cedex (France); Departement de Recherches Subatomiques, Institut Pluridisciplinaire Hubert-Curien, Groupe de Radioprotection et Mesures Environnementales (RaMsEs), Universite Louis Pasteur Strasbourg I, BP 28, 67037 Strasbourg Cedex 2 (France); Michielsen, N., E-mail: nathalie.michielsen@irsn.f [Institut de Radioprotection et de Surete Nucleaire (IRSN)/Service d' Etudes et de Recherches en Aerodispersion des polluants et en Confinement, B.P 68, 91192 Gif-sur-Yvette Cedex (France); Della-Negra, S. [Institut de Physique Nucleaire (IPN), F-91406 Orsay (France); Nourreddine, A.; Baussan, E. [Departement de Recherches Subatomiques, Institut Pluridisciplinaire Hubert-Curien, Groupe de Radioprotection et Mesures Environnementales (RaMsEs), Universite Louis Pasteur Strasbourg I, BP 28, 67037 Strasbourg Cedex 2 (France)

    2009-10-15

    The chemical and physical properties of a radioactive nanometric aerosol are important in determining its behaviour in indoor atmospheres and play a major part in determining its potential health effects. In a well defined experimental system, mass spectrometry coupled to the Time-of-Flight technique, we measured the electric charge of {sup 218}Po at the end of its recoil path. The charge distribution of the recoiling {sup 218}Po is mainly neutral and singly charged with a very small multicharged fraction. In case of radon progeny embedded in solid matter this one can play a major role in the surface ionisation processes versus electron and ion emission induced by the passage of the alpha recoils through the surface.

  1. Frequency of Angina Pectoris After Percutaneous Coronary Intervention and the Effect of Metallic Stent Type.

    Science.gov (United States)

    Gaglia, Michael A; Torguson, Rebecca; Lipinski, Michael J; Gai, Jiaxiang; Koifman, Edward; Kiramijyan, Sarkis; Negi, Smita; Rogers, Toby; Steinvil, Arie; Suddath, William O; Satler, Lowell F; Pichard, Augusto D; Waksman, Ron

    2016-02-15

    Although metallic coronary stents significantly reduce angina pectoris compared with optimal medical therapy, angina after percutaneous coronary intervention (PCI) remains frequent. We, therefore, sought to compare the incidence of any angina during the 1 year after PCI among the spectrum of commercially available metallic stents. Metallic stent type was classified as bare metal stent, Cypher, Taxus Express, Xience V, Promus Element, and Resolute. The primary end point was patient-reported angina within 1 year of PCI. Multivariable logistic regression was performed to assess the independent association of stent type with any angina at 1 year. Overall, 8,804 patients were queried in regard to angina symptoms; 32.3% experienced angina at some point in the first year after PCI. Major adverse cardiovascular events, a composite of all-cause mortality, target vessel revascularization, and Q-wave myocardial infarction, increased with angina severity: 6.8% for patients without angina, 10.0% for patients with class 1 or 2 angina, and 19.7% for patients with class 3 or 4 angina (p angina at 1 year after PCI. Baseline Canadian Cardiovascular Society class 3 or 4 angina, history of coronary artery bypass grafting, and history of PCI were associated with a higher likelihood of angina at 1 year; increasing age, male gender, presentation with acute coronary syndrome, and higher stented length were associated with less angina. In conclusion, metallic stent type is not associated with the occurrence of angina at up to 1 year after PCI.

  2. Evaluating Stent Optimisation Technique (StentBoost®) in a Dedicated Bifurcation Stent (the Tryton™)

    Energy Technology Data Exchange (ETDEWEB)

    Fysal, Zamil; Hyde, Thomas; Barnes, Edward; McCrea, William; Ramcharitar, Steve, E-mail: steve.ramcharitar@chem.ox.ac.uk

    2014-03-15

    Background/Purpose: To evaluate the use of StentBoost® in the Tryton™ dedicated SideBranch Stent. Methods and Results: The Tryton™ SideBranch Stent has been effectively used to manage complex bifurcations. However, the paucity of scaffolding in the proximal part of the stent makes it often difficult to visualise under standard radiographic imaging. We set out to evaluate whether by using an augmented radiographic imaging technique it was possible to aid visualisation of the stent. In particular the so call 'wedding ring' band which is crucial to the procedural success. We further evaluated whether it was possible to determine the apposition of the stent at the carina, its coverage and the ability to aid recrossing of the struts closest to the carina as well as the added radiation exposure. Conclusions: StentBoost® was found to be invaluable to the procedural success of the Tryton™ deployment without adding any extra cost to the procedure and with only a 3.7% increase in radiation to the patient. It allowed enhanced visualisation in all cases to aid apposition, recrossing and coverage.

  3. Computing at the Dubna gas-filled recoil separator

    Science.gov (United States)

    Tsyganov, Yuri S.; Polyakov, Alexandr N.

    2006-03-01

    Simulation codes for the spectra of heavy implanted nuclei, applications for online data visualization and real time PC-based algorithms are considered. Special attention is paid to the application of real time techniques for radical suppression of background products in heavy-ion-induced nuclear reactions at the U-400 cyclotron of the Flerov Laboratory of Nuclear Reactions. The detection system of the Dubna gas-filled recoil separator (DGFRS) is also briefly described. Calculated heavy recoil spectra are compared with those measured in heavy-ion-induced nuclear reactions.

  4. Application Effect of Secondary Thrombus Aspiration After Stent Implantation in Acute Myocardial Infarction Patients Treated by Emergency PCI%支架置入术后再次血栓抽吸术在急性心肌梗死患者急诊经皮冠状动脉介入治疗中的应用效果评价

    Institute of Scientific and Technical Information of China (English)

    邵强

    2016-01-01

    目的 评价支架置入术后再次血栓抽吸术在急性心肌梗死患者急诊经皮冠状动脉介入治疗(PCI)中的应用效果.方法 选取2013年11月—2015年11月凉山彝族自治州第二人民医院收治的急性心肌梗死患者158例,按照随机数字表法分为研究组和对照组,每组79例.两组患者均行急诊PCI,确定梗死相关血管(IRA)后实施血栓抽吸术,然后实施球囊扩张术及支架置入术,研究组患者在支架置入术后再次实施血栓抽吸术.比较两组患者支架置入术后TIMI血流分级、TIMI心肌灌注(TMP)分级及研究组患者支架置入术后和再次血栓抽吸术后TIMI血流分级、TMP分级,比较两组患者术后ST段回落指数,并统计两组患者住院期间及出院后随访15周不良心血管事件发生情况.结果 支架置入术后两组患者TIMI血流分级和TMP分级比较,差异无统计学意义(u值分别为0.292、0.208,P>0.05);研究组患者再次血栓抽吸术后TIMI血流分级和TMP分级优于支架置入术后(u值分别为3.177、3.906,P0.05).结论 支架置入术后再次血栓抽吸术可有效促进急性心肌梗死患者急诊PCI术后梗死血管再通,改善梗死区域心肌灌注,提高临床疗效,降低近期不良心血管事件发生风险.%Objective To evaluate the application effect of secondary thrombus aspiration after stent implantation in acute myocardial infarction patients treated by emergency PCI. Methods A total of 158 patients with acute myocardial infarction were selected in the Second People's Hospital of Liangshan Yi Autonomous Prefecture from November 2013 to November 2015, and they were divided into control group and study group according to random number table,each of 79 cases. Patients of both groups received emergency PCI after admission,and all of them received thrombus aspiration after definition of infarction related artery,after then were given balloon dilatation and stent implantation,while patients of study

  5. Drug-eluting versus bare metal stents in patients with st-segment-elevation myocardial infarction: eight-month follow-up in the Drug Elution and Distal Protection in Acute Myocardial Infarction (DEDICATION) trial

    DEFF Research Database (Denmark)

    Kelbaek, Henning; Thuesen, Leif; Helqvist, Steffen

    2008-01-01

    BACKGROUND: Implantation of drug-eluting stents (DES) limits the rate of coronary restenosis in most patients with coronary artery disease, but data are scarce with regard to their use in patients with ST-segment-elevation myocardial infarction and in connection with distal protection of the micr......BACKGROUND: Implantation of drug-eluting stents (DES) limits the rate of coronary restenosis in most patients with coronary artery disease, but data are scarce with regard to their use in patients with ST-segment-elevation myocardial infarction and in connection with distal protection...... of the microvascular perfusion during primary percutaneous coronary intervention. METHODS AND RESULTS: We randomly assigned 626 patients referred within 12 hours from symptom onset of an ST-elevation myocardial infarction to have a DES or a bare metal stent implanted in the infarct-related lesion with or without...... distal protection during primary percutaneous coronary intervention. Quantitative coronary angiography was performed during the index treatment and 8 months later. The primary end point was loss of the lumen diameter in the infarct-related lesion induced by neointimal proliferation. Patients were...

  6. Recoil-alpha-fission and recoil-alpha-alpha-fission events observed in the reaction Ca-48 + Am-243

    CERN Document Server

    Forsberg, U; Andersson, L -L; Di Nitto, A; Düllmann, Ch E; Gates, J M; Golubev, P; Gregorich, K E; Gross, C J; Herzberg, R -D; Hessberger, F P; Khuyagbaatar, J; Kratz, J V; Rykaczewski, K; Sarmiento, L G; Schädel, M; Yakushev, A; Åberg, S; Ackermann, D; Block, M; Brand, H; Carlsson, B G; Cox, D; Derkx, X; Dobaczewski, J; Eberhardt, K; Even, J; Fahlander, C; Gerl, J; Jäger, E; Kindler, B; Krier, J; Kojouharov, I; Kurz, N; Lommel, B; Mistry, A; Mokry, C; Nazarewicz, W; Nitsche, H; Omtvedt, J P; Papadakis, P; Ragnarsson, I; Runke, J; Schaffner, H; Schausten, B; Shi, Y; Thörle-Pospiech, P; Torres, T; Traut, T; Trautmann, N; Türler, A; Ward, A; Ward, D E; Wiehl, N

    2015-01-01

    Products of the fusion-evaporation reaction Ca-48 + Am-243 were studied with the TASISpec set-up at the gas-filled separator TASCA at the GSI Helmholtzzentrum f\\"ur Schwerionenforschung. Amongst the detected thirty correlated alpha-decay chains associated with the production of element Z=115, two recoil-alpha-fission and five recoil-alpha-alpha-fission events were observed. The latter are similar to four such events reported from experiments performed at the Dubna gas-filled separator. Contrary to their interpretation, we propose an alternative view, namely to assign eight of these eleven decay chains of recoil-alpha(-alpha)-fission type to start from the 3n-evaporation channel 115-288. The other three decay chains remain viable candidates for the 2n-evaporation channel 115-289.

  7. Endoscopic placement of pancreatic stents and drains in the management of pancreatitis.

    Science.gov (United States)

    Kozarek, R A; Patterson, D J; Ball, T J; Traverso, L W

    1989-01-01

    Although widely used in the biliary tree, little data is available on endoscopic placement of stents or drains within the pancreas. This report describes 17 patients, nine with acute relapsing pancreatitis and eight with chronic pancreatitis, who had drain or stent placement for hypertensive pancreatic duct (PD) sphincter, dominant ductal stenosis, duct disruption, or pseudocyst. Two patients have subsequently undergone surgery, and six other patients continue long-term stent placement with marked reduction of chronic pain or attacks of recurrent pancreatitis. All six pseudocysts resolved, although one recurred and required surgery. It is concluded that pancreatic drains or stents may obviate the need for surgery, temporize before definitive therapy, or direct a subsequent surgical procedure. Images Figs. 1A and B. Figs. 2A-C. Figs. 2A-C. Fig. 3. Figs. 4A-D. Figs. 5A and B. PMID:2923512

  8. Novel side branch ostial stent.

    Science.gov (United States)

    Chen, Shao-Liang; Lv, Shu-Zheng; Kwan, Tak W

    2009-04-01

    Bifurcation lesions are technically challenging and plagued by a high incidence of restenosis, especially at the side branch orifice, which results in a more frequent need for revascularization during the follow-up period. This report discusses two clinical experiences with a novel side branch ostial stent, the BIGUARD stent, designed for the treatment of bifurcation lesions; procedural success with no in-hospital complications was observed in types IVb and Ia lesions.

  9. Endovascular stent-graft management of thoracic aortic diseases

    Energy Technology Data Exchange (ETDEWEB)

    Dake, Michael D. E-mail: mddake@stanford.edu

    2001-07-01

    The traditional standard therapy for descending thoracic aortic aneurysm (TAA) is open operative repair with graft replacement of the diseased aortic segment. Despite important advances in surgical techniques, anesthetic management, and post-operative care over the last 30 years, the mortality and morbidity of surgery remains considerable, especially in patients at high risk for thoracotomy because of coexisting severe cardiopulmonary abnormalities or other medical diseases. The advent of endovascular stent-graft technology provides an alternative to open surgery for selected patients with TAA. The initial experience suggests that stent-graft therapy potentially may reduce the operative risk, hospital stay and procedural expenses of TAA repair. These potential benefits are especially attractive for patients at high risk for open TAA repair. Current results of endovascular TAA therapy document operative mortalities of between 0 and 4%, aneurysm thrombosis in 90 and 100% of cases, and paraplegia as a complication in 0 and 1.6% of patients. The early success of stent-graft repair of TAA has fostered the application of these devices for the management of a wide variety of thoracic aortic pathologies, including acute and chronic dissection, intramural hematoma, penetrating ulcer, traumatic injuries, and other diseases. The results of prospective controlled trials that compare the outcomes of stent-graft therapy with those of surgical treatment in patients with specific types of aortic disease are anxiously awaited before recommendations regarding the general use of these new devices can be made with confidence.

  10. Long-term outcome after drug-eluting versus bare-metal stent implantation in patients with ST-segment elevation myocardial infarction: 3-year follow-up of the randomized DEDICATION (Drug Elution and Distal Protection in Acute Myocardial Infarction) Trial

    DEFF Research Database (Denmark)

    Kaltoft, Anne; Kelbaek, Henning; Thuesen, Leif

    2010-01-01

    The purpose of this study was to compare long-term clinical outcomes after implantation of drug-eluting stents (DES) and bare-metal stents (BMS) in patients with ST-segment elevation myocardial infarction (STEMI).......The purpose of this study was to compare long-term clinical outcomes after implantation of drug-eluting stents (DES) and bare-metal stents (BMS) in patients with ST-segment elevation myocardial infarction (STEMI)....

  11. Inappropriateness in biliary stenting

    Directory of Open Access Journals (Sweden)

    Giuseppe Chesi

    2013-10-01

    Full Text Available Starting from a real case of a 69-year old patient affected by cholangiocarcinoma, we intend to discuss the accuracy and appropriateness of the diagnostic and therapeutic procedures adopted. This case shows in particular that a more accurate preoperative staging could probably avoid the patient unnecessary laparotomy. According to the indications in the medical literature, this patient could possibly benefit from chemotherapy, but a chemoembolization of liver metastases was performed. However in the literature no available evidence suggests that this treatment would be beneficial in this kind of clinical picture. Eventually, when the disease was already at an advanced stage and worsened due to a necrosis of the left hepatic lobe and a cholangitic infection, a repositioning of the stent on the stent was performed, despite in the literature the life expectancy cut-off for this procedure is at least 6 months. We also discuss the communication between the physician, the patient and the family, which was probably based on overly optimistic and unrealistic expectations. This led to a number of surgical procedures, which were not certainly helpful and indeed were probably even harmful for this patient. In addition, these procedures caused unnecessary costs borne by the healthcare system. In conclusion, we advocate that discussion and self-assessment must be always promoted, so that the healthcare professionals can review the process and the outcome of their treatment as well as their behavior to understand if it could have been more appropriate to offer actual benefits to the patients in terms of better quality of life and longer life expectancy.

  12. Emergency and elective implantation of covered stent systems in iatrogenic arterial injuries

    Energy Technology Data Exchange (ETDEWEB)

    Goltz, J.P.; Kickuth, R. [Universitaetsklinikum Wuerzburg (Germany). Inst. fuer Roentgendiagnostik; Bastuerk, P.; Hoppe, H.; Triller, J. [Universitaetsspital Bern (Switzerland). Inst. fuer Diagnostische, Interventionelle und Paediatrische Radiologie

    2011-07-15

    Purpose: To evaluate the effectiveness and safety of covered stents for the management of iatrogenic arterial injury. Materials and Methods: Between 03/1998 and 12/2009, 31 patients underwent selective covered stent implantation after iatrogenic arterial injury. 12/31 of these patients (38.7 %) were hemodynamically unstable. Six different endovascular covered stent types were utilized. The primary endpoints of this study were technical and clinical success and rates of minor and major complications. Results: Initial angiograms demonstrated active extravasation in 19 (61.3 %) patients and pseudoaneurysms in 12 (38.7 %) patients. The following sites of bleeding origin were detected: axillary artery, subclavian artery, common iliac artery, external iliac artery, internal iliac artery, common femoral artery, superficial femoral artery, popliteal and fibular artery, femoro-popliteal and popliteo-crural bypasses, common hepatic artery, aberrant hepatic artery, cystic and gastroduodenal artery. In all patients bleeding was effectively controlled by covered stent implantation resulting in an immediate technical success of 100 %. Clinical success attributed to covered stent implantation was documented in 30 of the 31 patients (96.8 %). Major complications included death in four patients (11.1 %), acute thrombosis with arm ischemia in one patient (2.8 %) and stent fracture with associated pseudoaneurysm in another patient (2.8 %). In 2/31 patients (6.5 %) covered stent failure was detected and successfully treated by implantation of a second covered stent. Conclusion: Emergency and elective implantation of covered stents may be used for minimally invasive and effective management of iatrogenic arterial injury. (orig.)

  13. Coronary aneurysm and very late stent thrombosis formation associated with sirolimus-eluting stent implantation

    Institute of Scientific and Technical Information of China (English)

    XIE Hong-zhi; ZHANG Shu-yang; ZENG Yong; SHEN Zhu-jun; FANG Quan

    2009-01-01

    @@ Since drug-eluting stents (DES) can significantly reduce the risk of instant restenosis compared with bare-metal stents, they have been widely used in interventional therapy for coronary heart disease. With bare-metal stents being rapidly replaced by DES there is a great concern about the safety of DES due to stent thrombosis.~(1,2)

  14. Direct Measurement of Photon Recoil from a Levitated Nanoparticle

    Science.gov (United States)

    Jain, Vijay; Gieseler, Jan; Moritz, Clemens; Dellago, Christoph; Quidant, Romain; Novotny, Lukas

    2016-06-01

    The momentum transfer between a photon and an object defines a fundamental limit for the precision with which the object can be measured. If the object oscillates at a frequency Ω0 , this measurement backaction adds quanta ℏΩ0 to the oscillator's energy at a rate Γrecoil, a process called photon recoil heating, and sets bounds to coherence times in cavity optomechanical systems. Here, we use an optically levitated nanoparticle in ultrahigh vacuum to directly measure Γrecoil. By means of a phase-sensitive feedback scheme, we cool the harmonic motion of the nanoparticle from ambient to microkelvin temperatures and measure its reheating rate under the influence of the radiation field. The recoil heating rate is measured for different particle sizes and for different excitation powers, without the need for cavity optics or cryogenic environments. The measurements are in quantitative agreement with theoretical predictions and provide valuable guidance for the realization of quantum ground-state cooling protocols and the measurement of ultrasmall forces.

  15. X-ray spectroscopy of a recoiling SMBH candidate

    Science.gov (United States)

    Predehl, Peter

    2008-09-01

    Recent numerical relativity simulations of coalescencing supermassive black hole (SMBH) binaries predict that SMBHs can receive kicks with velocities up to several thousand km/s due to anisotropic emission of gravitational waves. We have recently found the best candidate todate for such a recoiling SMBH (Komossa et al. 2008). We apply for a 25 ks ACIS-S exposure of this exceptional source.

  16. Three-dimensional reconstruction of coronary stents in vivo based on motion compensated X-ray angiography

    Science.gov (United States)

    Schäfer, Dirk; Movassaghi, Babak; Grass, Michael; Schoonenberg, Gert; Florent, Raoul; Wink, Onno; Klein, Andrew J. P.; Chen, James Y.; Garcia, Joel; Messenger, John C.; Carroll, John D.

    2007-03-01

    The complete expansion of the stent during a percutaneous transluminal coronary angioplasty (PTCA) procedure is essential for treatment of a stenotic segment of a coronary artery. Inadequate expansion of the stent is a major predisposing factor to in-stent restenosis and acute thrombosis. Stents are positioned and deployed by fluoroscopic guidance. Although the current generation of stents are made of materials with some degree of radio-opacity to detect their location after deployment, proper stent expansion is hard to asses. In this work, we introduce a new method for the three-dimensional (3D) reconstruction of the coronary stents in-vivo utilizing two-dimensional projection images acquired during rotational angiography (RA). The acquisition protocol consist of a propeller rotation of the X-ray C-arm system of 180°, which ensures sufficient angular coverage for volume reconstruction. The angiographic projections were acquired at 30 frames per second resulting in 180 projections during a 7 second rotational run. The motion of the stent is estimated from the automatically tracked 2D coordinates of the markers on the balloon catheter. This information is used within a motion-compensated reconstruction algorithm. Therefore, projections from different cardiac phases and motion states can be used, resulting in improved signal-to-noise ratio of the stent. Results of 3D reconstructed coronary stents in vivo, with high spatial resolution are presented. The proposed method allows for a comprehensive and unique quantitative 3D assessment of stent expansion that rivals current X-ray and intravascular ultrasound techniques.

  17. Very late coronary aneurysm formation with subsequent stent thrombosis secondary to drug-eluting stent

    Institute of Scientific and Technical Information of China (English)

    Ibrahim Akin,; Stephan Kische; Tim C Rehders; Henrik Schneider; G(o)kmen R Turan; Tilo Kleinfeldt; Jasmin Ortak; Christoph A. Nienaber; Hüseyin Ince

    2011-01-01

    Drug-eluting stents have changed the practice in interventional cardiology.With the widespread use of these stents important safety concerns regarding stent thrombosis and formation of coronary artery aneurysm have been expressed.While the majority of attention was focused on stent thrombosis,the formation of coronary aneurysm was only described in anecdotal reports.We report on a patient who suffered from very late stent thrombosis in association with coronary artery aneurysm formation secondary to drug-eluting stent but not to bare-metal stent.

  18. The role of carotid artery stenting for recent cerebral ischemia.

    Science.gov (United States)

    Bosiers, M; Callaert, J; Deloose, K; Verbist, J; Keirse, K; Peeters, P

    2010-06-01

    Patients with cerebral ischemia as a result of acute cervical internal carotid artery occlusion are generally considered to have a poor prognosis. Despite maximal medical treatment, a better treatment for patients with acute ischemic stroke who present with serious neurologic symptoms on admission or continue to deteriorate neurologically due to a total occlusion, a dissection or a high-grade stenosis of the internal carotid artery is required. An effective intervention to improve their neurologic symptoms and clinical outcome has not yet been established and represents a challenging and complex problem. Treatment of acute symptomatic occlusion of the cervical internal carotid artery includes intravenous administration of thrombolytic agent, carotid endarterectomy and an interventional approach (intra-arterial administration of thrombolytic agent, transluminal angioplasty with or without stenting). The endovascular interventional approach is becoming a part of the stroke therapy armamentarium for intracranial occlusion. It may also now be considered in select patients with acute internal carotid artery occlusion. Stenting and angioplasty for acute internal carotid artery occlusion appears to be feasible, safe and may be associated with early neurological improvement. The encouraging preliminary results await confirmation from prospective, randomized studies.

  19. Mechanisms of Biliary Plastic Stent Occlusion and Efforts at Prevention

    Science.gov (United States)

    Kwon, Chang-Il; Lehman, Glen A.

    2016-01-01

    Biliary stenting via endoscopic retrograde cholangiopancreatography has greatly improved the quality of patient care over the last 30 years. Plastic stent occlusion limits the life span of such stents. Attempts to improve plastic stent patency duration have mostly failed. Metal stents (self-expandable metal stents [SEMSs]) have therefore replaced plastic stents, especially for malignant biliary strictures. SEMS are at least 10 times more expensive than plastic stents. In this focused review, we will discuss basic mechanisms of plastic stent occlusion, along with a systematic summary of previous efforts and related studies to improve stent patency and potential new techniques to overcome existing limitations. PMID:27000422

  20. Preventive role of palladium-103 radioactive stent on in-stent restenosis in rabbit iliac arteries

    Institute of Scientific and Technical Information of China (English)

    LUO Quan-Yong; CHEN Li-Bo; YUAN Zhi-Bin; LU Han-Kui; ZHU Rui-Sen

    2005-01-01

    The abilility of γ-emitting palladium-103 stent implantation to inhibit in-stent restenosis in rabbit iliac arteries was investigated. Quantitative histomorphometry of the stented iliac segments 28 days after the implantation indicated that palladium-103 stents made a significant reduction in neointimal area and percent area stenosis compared with the nonradioactive stents. Lumen area in the palladium-103 stents treatment group was larger than the control group. However, the reduction of neointima formation by palladium-103 stents implantation was in a non-dose-dependent fashion. Low ionizing radiation doses via γ-emitting palladiurn-103 stent are effective in preventing neointimal hyperplasia in iliac arteries of rabbits. Palladium-103 stents can be employed as a possible novel means to prevent in-stent restenosis.

  1. The risk and prognostic impact of definite stent thrombosis or in-stent restenosis after coronary stent implantation

    DEFF Research Database (Denmark)

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

    2012-01-01

    of death (HR=2.71 [95% CI: 1.72-4.27]) compared to cases without stent thrombosis. In-stent restenosis had no substantial impact (HR=1.17 [95% CI: 0.79-1.75]). However, in-stent restenosis presenting as non-ST-segment elevation myocardial infarction (NSTEMI) was associated with a greater mortality risk...

  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. Time course, predictors and clinical implications of stent thrombosis following primary angioplasty. Insights from the DESERT cooperation

    DEFF Research Database (Denmark)

    De Luca, Giuseppe; Dirksen, Maurits T; Spaulding, Christian;

    2013-01-01

    on the timing of stent thrombosis (ST) with both DES and bare metal stents (BMS) and its prognostic significance in patients undergoing pPCI. The Drug-Eluting Stent in Primary Angioplasty (DESERT) cooperation is based on a pooled database including individual data of randomised trials that evaluate the long...... angioplasty with BMS or DES. At 1201 ± 440 days, ST occurred in 267 patients (4.25%). Most of the events were acute or subacute (within 30 days) and very late (> 1 years), with different distribution between DES vs BMS. Patients with ST were more often diabetic (21.7% vs 15.1%, p=0.005), more frequently had...

  4. Incidence and predictors of coronary stent thrombosis

    DEFF Research Database (Denmark)

    D'Ascenzo, Fabrizio; Bollati, Mario; Clementi, Fabrizio;

    2013-01-01

    Stent thrombosis remains among the most feared complications of percutaneous coronary intervention (PCI) with stenting. However, data on its incidence and predictors are sparse and conflicting. We thus aimed to perform a collaborative systematic review on incidence and predictors of stent thrombo...

  5. 21 CFR 884.3900 - Vaginal stent.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Vaginal stent. 884.3900 Section 884.3900 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES... stent. (a) Identification. A vaginal stent is a device used to enlarge the vagina by stretching, or...

  6. Visualization of Stent Lumen in MR Imaging: Relationship with Stent Design and RF Direction

    Directory of Open Access Journals (Sweden)

    Ohno,Seiichiro

    2012-06-01

    Full Text Available Magnetic resonance imaging (MRI visualization of metallic stent lumens is possible if the stent structure counteracts eddy currents in the lumen induced by the radio frequency magnetic field, B1. To examine the effectiveness of various stent designs in counteracting eddy currents, we anchored eight copper stent models and 2 commercially available nickel-titanium alloy (Nitinol stents in a gel phantom, perpendicular or parallel to the direction of B1. A mesh stent lumen showed hypointensity irrespective of its alignment relative to B1. A solenoid stent lumen showed hypointensity with the stent axis parallel to B1, but it had the same signal intensity as outside the lumen when perpendicular to B1. A Moebius stent lumen showed no signal reduction, irrespective of alignment relative to B1. Lumens of the commercially available stents showed hypointensity regardless of alignment relative to B1. Computer simulation revealed that the signal intensities of the stents corresponded to magnetic flux densities of B1 in the stents, which are modified by the structure of the stent. While in vivo MRI viewing of a Moebius stent lumen is likely possible regardless of axis alignment, inherent structural weakness may be problematic. As a more practical choice, the solenoid stent is easier to manufacture and generates no hypointensive signal when the axis is parallel to B0.

  7. 主动脉弓三分支覆膜支架在Stanford A型急性主动脉夹层外科治疗中的应用%The application of triple branches aortic arch stent-graft placement in the surgical treatment of acute Stanford type A aortic dissection

    Institute of Scientific and Technical Information of China (English)

    华菲; 沈振亚; 余云生; 叶文学; 黄浩岳

    2011-01-01

    目的 总结外科处理升主动脉加主动脉弓三分支覆膜支架置入治疗Stanford A型急性主动脉夹层的临床经验.方法 对2010年1月至12月收治的14例Stanford A型主动脉夹层患者行升主动脉手术处理加主动脉弓三分支覆膜支架置入,其中男性12例,女性2例,年龄20~70岁,平均49岁.手术包括升主动脉置换术加支架置入4例,主动脉根部置换术(Bentall术)加支架置入5例,主动脉瓣置换加升主动脉置换术(Wheat术)加支架置入4例,主动脉瓣成形加升主动脉置换术加支架置入1例;其中6例为急诊手术.结果 平均心肺转流时间(186±38)min,心肌阻断时间(101±27)min,选择性脑灌注时间(39±11)min.无住院死亡病例;术后出现短暂性神志障碍1例,肢体活动障碍1例,急性肾功能衰竭1例,二次开胸手术1例,消化道出血1例,乳糜胸1例,治疗后均痊愈.出院前及出院后3个月内行大血管CT血管造影检查:升主动脉及弓部覆膜支架内血流通畅,主动脉弓段及降主动脉假腔缩小,主动脉管壁结构恢复.随访1~12个月,无晚期死亡及需要再次手术纠治血管病变者.结论 主动脉弓三分支覆膜支架置入的主要适应证为内膜破口位于升主动脉但需重建弓部形态的Stanford A型急性主动脉夹层.其同期结合手术处理升主动脉是治疗急性Stanford A型主动脉夹层安全、有效的一种新手段.%Objective To sum up the experience of performing ascending aorta replacement combined triple-branched stent graft implantation for acute Standford type A aortic dissection. Methods From January 2010 to December 2010, 14 patients with acute Standford type A aortic dissection underwent the procedure of performing ascending aorta replacement combined triple-branched stent graft implantation.Right axiuary artery cannulation was used for cardiopulmonary bypass and selected cerebral perfusion.When the body temperature drops below 18 ℃, the ascending aorta

  8. Acute superior mesenteric ischemia: a contrast syudy on short-and mid-term result between stent implantation and pharmaceutical thrombolysis%急性肠系膜上动脉缺血的支架置入与药物溶栓近、中期疗效分析

    Institute of Scientific and Technical Information of China (English)

    张曦彤; 张洪义; 张伟; 洪铎; 安建立; 夏永辉; 徐克

    2011-01-01

    目的 比较支架置入与药物溶栓治疗急性肠系膜上动脉缺血的近、中期疗效.方法 收集2004年1月至2008年12月,中国医科大学附属第一医院因肠系膜上动脉狭窄或闭塞引起急性肠缺血住院患者35例.其中,支架置入12例(介入治疗组),外周药物溶栓23例(药物溶栓组).介入治疗组采用球囊扩张及支架置入并辅以抗凝、祛聚及扩血管治疗,药物溶栓组采用尿激酶配合抗凝、祛聚及扩血管治疗.两组患者出院后均口服氯吡格雷及阿司匹林并进行随访.用Fisher确切概率法比较分析两组疗效差异的显著性.结果 药物溶栓组临床有效7例,无效16例(加重或死亡7例,治疗失败行部分肠切除9例).介入治疗组10例置入支架(1例术后第3天死于急性心肌梗死),2例开通失败.随访1~48(15±12)个月.药物溶栓组1例病情平稳,6例死于再发急性肠系膜动脉栓塞;支架置入组7例病情平稳,1例术后20个月死于急性心肌梗死(无肠缺血症状),1例术后28个月再发肠缺血,经肠系膜动脉置管溶栓后症状消失.结论 支架置入在改善肠系膜上动脉闭塞引起肠缺血及提高患者生存率方面均显著优于药物保守治疗,为尚未出现肠坏死患者的治疗方案的选择提供了可靠依据.%Objective To compare the short-term and medium-term result of stent implantation with pharmaceutical thrombolysis in patients with acute superior mesenteric artery occlusion. Methods From January, 2004 to December, 2008, thirty-five patients diagnosed acute superior mesenteric ischemia, 12 patients treated with stent implantation ( interventional therapy group) and 23 patients with pharmaceutical thrombolysis(thrombolytic therapy group). Interventional therapy group treated with balloon dilatation and stent implantation assisted with anticoagulation, antiplatelet and vascular dilation agents. Thrombolytic therapy group used urokinase combined with anticoagulation

  9. A Survey of Surface Modification Techniques for Next-Generation Shape Memory Polymer Stent Devices

    Directory of Open Access Journals (Sweden)

    Tina Govindarajan

    2014-08-01

    Full Text Available The search for a single material with ideal surface properties and necessary mechanical properties is on-going, especially with regard to cardiovascular stent materials. Since the majority of stent problems arise from surface issues rather than bulk material deficiencies, surface optimization of a material that already contains the necessary bulk properties is an active area of research. Polymers can be surface-modified using a variety of methods to increase hemocompatibilty by reducing either late-stage restenosis or acute thrombogenicity, or both. These modification methods can be extended to shape memory polymers (SMPs, in an effort to make these materials more surface compatible, based on the application. This review focuses on the role of surface modification of materials, mainly polymers, to improve the hemocompatibility of stent materials; additional discussion of other materials commonly used in stents is also provided. Although shape memory polymers are not yet extensively used for stents, they offer numerous benefits that may make them good candidates for next-generation stents. Surface modification techniques discussed here include roughening, patterning, chemical modification, and surface modification for biomolecule and drug delivery.

  10. Measurements of Scintillation Efficiency and Pulse-Shape for Low Energy Recoils in Liquid Xenon

    CERN Document Server

    Akimov, D Y; Davidge, D; Dawson, J; Howard, A S; Ivaniouchenkov, Yu; Jones, W G; Joshi, M; Kudryavtsev, V A; Lawson, T B; Lebedenko, V; Lehner, M J; Lightfoot, P K; Liubarsky, I; Lüscher, R; McMillan, J E; Peak, C D; Quenby, J J; Spooner, N J C; Sumner, T J; Tovey, Daniel R; Ward, C K

    2002-01-01

    Results of observations of low energy nuclear and electron recoil events in liquid xenon scintillator detectors are given. The relative scintillation efficiency for nuclear recoils is 0.22 +/- 0.01 in the recoil energy range 40 keV - 70 keV. Under the assumption of a single dominant decay component to the scintillation pulse-shape the log-normal mean parameter T0 of the maximum likelihood estimator of the decay time constant for 6 keV < Eee < 30 keV nuclear recoil events is equal to 21.0 ns +/- 0.5 ns. It is observed that for electron recoils T0 rises slowly with energy, having a value ~ 30 ns at Eee ~ 15 keV. Electron and nuclear recoil pulse-shapes are found to be well fitted by single exponential functions although some evidence is found for a double exponential form for the nuclear recoil pulse-shape.

  11. "Virtual" in-vivo bench test for bifurcation stenting with "StentBoost".

    Science.gov (United States)

    Agostoni, Pierfrancesco; Verheye, Stefan; Vermeersch, Paul; Cornelis, Kristoff; Van Langenhove, Glenn

    2009-04-01

    "StentBoost" is a new angiographic technique that allows improved angiographic visualization of stents deployed in coronary arteries, by enhancing the X-ray focus of the region where the stent is placed. Using this technique we were able to assess the deformation and the expansion of a stent deployed to treat a bifurcation lesion between the mid-left anterior descending (LAD) artery and a big second diagonal branch, during sequential inflations of: (1) the stent per se in the LAD, (2) the ostium of the diagonal branch through the stent struts, (3) the stent again with a non compliant balloon, and (4) both branches with the kissing balloon technique. "StentBoost" guided our clinical and angiographic decision-making process and allowed us to create a "virtual" bench test of the stent deployed at the level of the bifurcation treated.

  12. 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.

  13. Metallic stent placement for the management of acute colorectal obstruction caused by colorectal carcinomas: its effect on scheduled surgery%急性结肠梗阻支架置入对结直肠癌择期手术的作用

    Institute of Scientific and Technical Information of China (English)

    曹燕; 刘冰妍; 茅爱武; 殷响; 高中度

    2011-01-01

    Objective To prospectively evaluate the safety and clinical efficacy of a newly designed self-expandable metallic stent ( SEMS ) placement in the treatment of patients with acute malignant colorectal obstruction due to colorectal carcinomas. Methods During the period from April 2001 to October 2007 , a total of 52 patients with acute malignant colorectal obstruction were treated with stent placement by using a new designed SEMS, which was employed as a preoperative transit means. All the patients were followed up and the relevant data, including technical success rate, clinical efficacy, complications and overall survival rate, were documented. The results were analyzed. Results Stent placement was successfully carried out in all patients except for two patients who showed complete colorectal obstruction. No procedure-related complications occurred. Technical success rate was 96% ( 50/52 ). Two days after the treatment,, the relief rate of colorectal obstruction was 98% ( 49/50 ). Postoperative complications included stent migration ( n =4 ), anal pain ( n = 2 ) and stool impaction ( n = 1 ). The stool impaction seen in one patient was successfully removed away with endoscopic manipulation two days after stent placement. An elective one-stage surgical procedure was performed in all 50 patients who successfully received a SEMS placement within a mean interval of ( 8 ± 2 ) days ( ranged 4 - 11 days ) after stent placement. Mean follow-up time was ( 36 ± 12 ) months with a range of ( 3 - 70 ) months. All patients remained alive at the time of this report. Conclusion The newly designed SEMS placement used as a preoperative transit means is a safe and effective intervention for colonic decompression in patients with acute malignant colorectal obstruction due to colorectal carcinomas.It can reliably ensure most of patients with colorectal carcinomas to successfully accomplish an elective surgery. ( J Intervent Radiol, 2011, 20 : 799-802 )%目的 探讨自膨胀金

  14. The new vacuum-mode recoil separator MARA at JYFL

    Science.gov (United States)

    Sarén, J.; Uusitalo, J.; Leino, M.; Greenlees, P. T.; Jakobsson, U.; Jones, P.; Julin, R.; Juutinen, S.; Ketelhut, S.; Nyman, M.; Peura, P.; Rahkila, P.; Scholey, C.; Sorri, J.

    2008-10-01

    A new vacuum-mode recoil separator MARA (Mass Analysing Recoil Apparatus) is under design and construction at the Department of Physics in the University of Jyväskylä. The separator is intended to separate reaction products from the primary beam in mass region below A = 150 . The ion-optical configuration of the separator will be QQQDEDM, where a magnetic quadrupole (Q) triplet is followed by an electrostatic deflector (DE) and a magnetic dipole (DM). The total length of MARA will be less than 7.0 m and the first order resolving power more than 250 for a beam spot size of 2 mm. In this contribution the main properties of MARA are given and results from simulations are shown.

  15. Recoil Detection for the SEparator for CApture Reactions (SECAR)

    Science.gov (United States)

    Garrity, April; Blackmon, J. C.; Deibel, C. M.; Good, E.; Hood, A. A.; Secar Collaboration

    2016-09-01

    SECAR will be installed at NSCL/FRIB to directly measure (p, γ) and (α, γ) reactions that are important in extreme stellar environments. Highly selective recoil detection is necessary with SECAR to identify the heavy products of these reactions. We have developed a gas ionization chamber that augments a standard ΔE - E design with position sensitive capability. We will describe this unique design and its advantages. Initial testing experiments that characterize the position, energy and atomic number resolution of the detector will be presented. The new recoil detector will be characterized in further in-beam studies in the near future and will be installed at NSCL/FRIB by early 2018. Supported by NSF and the U.S. DOE Office of Nuclear Physics.

  16. Radiation pressure in SFA theory: retardation and recoil corrections

    CERN Document Server

    Krajewska, K

    2015-01-01

    Radiation pressure effects in ionization by short linearly-polarized laser pulses are investigated in the framework of strong-field approximation, in both nonrelativistic and relativistic formulations. Differences between both approaches are discussed, and retardation and recoil corrections are defined. It is demonstrated how these corrections can be incorporated into the nonrelativistic approach, leading to the so-called quasi-relativistic formulation. These three approaches are further applied to the analysis of signatures of radiation pressure in energy-angular distributions of photoelectrons. It is demonstrated that, for Ti:Sapphire laser pulses of intensities up to $10^{16}\\mathrm{W/cm}^2$, predictions of the quasi-relativistic formulation agree well with those of the full relativistic one, and that the recoil corrections contribute predominantly to the radiation pressure effects.

  17. Elastic recoil detection analysis of hydrogen in polymers

    Energy Technology Data Exchange (ETDEWEB)

    Winzell, T.R.H.; Whitlow, H.J. [Lund Univ. (Sweden); Bubb, I.F.; Short, R.; Johnston, P.N. [Royal Melbourne Inst. of Tech., VIC (Australia)

    1996-12-31

    Elastic recoil detection analysis (ERDA) of hydrogen in thick polymeric films has been performed using 2.5 MeV He{sup 2+} ions from the tandem accelerator at the Royal Melbourne Institute of Technology. The technique enables the use of the same equipment as in Rutherford backscattering analysis, but instead of detecting the incident backscattered ion, the lighter recoiled ion is detected at a small forward angle. The purpose of this work is to investigate how selected polymers react when irradiated by helium ions. The polymers are to be evaluated for their suitability as reference standards for hydrogen depth profiling. Films investigated were Du Pont`s Kapton and Mylar, and polystyrene. 11 refs., 3 figs.

  18. Influence of metal alloy and the profile of coronary stents in patients with multivessel coronary disease

    Directory of Open Access Journals (Sweden)

    Luciano Maurício de Abreu Filho

    2011-01-01

    Full Text Available BACKGROUND: In Brazil, despite the recommendations of the Brazilian Society of Hemodynamics and Interventional Cardiology, the National Health System has not yet approved the use of drug-eluting stents. In percutaneous coronary interventions performed in the public and part of the private health care system, bare metal stents are used as the only option. Therefore, new information on bare metal stents is of great importance. The primary endpoint was to evaluate the influence of the alloy and the profile of coronary stents on late loss and restenosis rates 6 months after implantation in patients with multivessel coronary disease. METHODS: Single center, randomized and prospective study comparison of cobalt-chromium versus stainless steel stent implantation in 187 patients with multivessel coronary disease. At least one cobalt-chromium and one stainless steel stent were implanted per patient. RESULTS: Mean age of patients was 59.5 + 10.1 years with a prevalence of males (66.3% and patients with acute coronary syndrome (56%. Baseline clinical characteristics were similar with hypertension in 146 (78%, dyslipidemia in 85 (45.5% and diabetes in 68 (36.4%. Two hundred and twenty-nine cobalt-chromium and 284 stainless steel stents were implanted. Angiographic variables showed no statistically significant difference. Angiographic follow-up to 6 months after implantation showed similar late loss and restenosis rates. CONCLUSION: The use of two different alloys, stainless steel and cobalt-chrome stents, in the same patient and in the same vessel produced similar 6-month restenosis and late loss rates.

  19. Three dimensional momentum distributions of recoil-ions and photoelectrons

    Energy Technology Data Exchange (ETDEWEB)

    Ullrich, J.; Schmitt, W. [Gesellschaft fuer Schwerionenforschung mbH, Darmstadt (Germany); Doerner, R.; Jagutzki, O.; Mergel, V.; Moshammer, R.; Schmidt-Boecking, H.; Spielberger, L.; Unverzagt, M.; Vogt, T. [Frankfurt Univ. (Germany). Inst. fuer Kernphysik

    1996-10-01

    A novel high-resolution technique, the Multi-Electron-Recoil-Ion Momentum Spectroscopy, allows to determine in coincidence the three dimensional momentum vectors of the ion and up to three electrons created in any photo ionization event. At a solid angle of 4 {pi} the energy-resolutions for ions and electrons are {+-}2{mu} eV and {+-}10 meV, respectively. (orig.)

  20. The median recoil direction as a WIMP directional detection signal

    OpenAIRE

    Green, Anne M; MORGAN, BEN

    2010-01-01

    Direct detection experiments have reached the sensitivity required to detect dark matter WIMPs. Demonstrating that a putative signal is due to WIMPs, and not backgrounds, is a major challenge however. The direction dependence of the WIMP scattering rate provides a potential WIMP `smoking gun'. If the WIMP distribution is predominantly smooth, the Galactic recoil distribution is peaked in the direction opposite to the direction of Solar motion. Previous studies have found that, for an ideal de...

  1. Recoiling supermassive black holes: a search in the nearby universe

    Energy Technology Data Exchange (ETDEWEB)

    Lena, D.; Robinson, A.; Axon, D. J.; Merritt, D. [School of Physics and Astronomy, Rochester Institute of Technology, 84 Lomb Memorial Drive, Rochester, NY 14623-5603 (United States); Marconi, A. [Dipartimento di Fisica e Astronomia, Università degli Studi di Firenze, Largo E. Fermi 2, I-50125, Firenze (Italy); Capetti, A. [INAF-Osservatorio Astronomico di Torino, Strada Osservatorio 20, I-10025 Pino Torinese (Italy); Batcheldor, D., E-mail: dxl1840@g.rit.edu [Department of Physics and Space Sciences, Florida Institute of Technology, 150 West University Boulevard, Melbourne, FL 32901 (United States)

    2014-11-10

    The coalescence of a binary black hole can be accompanied by a large gravitational recoil due to anisotropic emission of gravitational waves. A recoiling supermassive black hole (SBH) can subsequently undergo long-lived oscillations in the potential well of its host galaxy, suggesting that offset SBHs may be common in the cores of massive ellipticals. We have analyzed Hubble Space Telescope archival images of 14 nearby core ellipticals, finding evidence for small (≲ 10 pc) displacements between the active galactic nucleus (AGN; the location of the SBH) and the center of the galaxy (the mean photocenter) in 10 of them. Excluding objects that may be affected by large-scale isophotal asymmetries, we consider six galaxies to have detected displacements, including M87, where a displacement was previously reported by Batcheldor et al. In individual objects, these displacements can be attributed to residual gravitational recoil oscillations following a major or minor merger within the last few gigayears. For plausible merger rates, however, there is a high probability of larger displacements than those observed, if SBH coalescence took place in these galaxies. Remarkably, the AGN-photocenter displacements are approximately aligned with the radio source axis in four of the six galaxies with displacements, including three of the four having relatively powerful kiloparsec-scale jets. This suggests intrinsic asymmetries in radio jet power as a possible displacement mechanism, although approximate alignments are also expected for gravitational recoil. Orbital motion in SBH binaries and interactions with massive perturbers can produce the observed displacement amplitudes but do not offer a ready explanation for the alignments.

  2. Recoiled Proton Tagged Knockout Reaction for 8He

    Institute of Scientific and Technical Information of China (English)

    曹中鑫; 叶沿林; 江栋兴; 郑涛; 李智焕; 华辉; 葛榆成; 李湘庆; 楼建玲; 肖军; 李奇特; 吕林辉; 李阔昂; 王赫; 乔锐; 游海波; 陈瑞九

    2012-01-01

    An experiment for knockout reaction induced by SHe beam at 82.5 MeV/nucleon on CH2 and C targets was carried out. The 6He and 4He core fragments at forward angles and the recoiled protons at large angles were detected coincidently. From this exclusive measurement the valence nucleon knockout mechanism and the core knockout mechanism are separated, which can be applied to the exclusive spectroscopic study on the structure of exotic nuclei.

  3. Local Delivery of Antiproliferative Agents via Stents

    Directory of Open Access Journals (Sweden)

    Hyuck Joon Kwon

    2014-03-01

    Full Text Available A stent is a medical device for serving as an internal scaffold to maintain or increase the lumen of a body conduit. Stent placement has become a primary treatment option in coronary artery disease for more than the last two decades. The stenting is also currently used for relieving the symptoms of narrowed lumen of nonvascular organs, such as esophagus, trachea and bronchi, small and large intestines, biliary, and urinary tract. Local delivery of active pharmaceutical agents via the stents can not only enhance healing of certain diseases, but it can also help decrease the potential risk of the stenting procedure to the surrounding tissue. In this review, we focus on reviewing a variety of drug-impregnated stents and local drug delivery systems using the stents.

  4. Prevention of stent thrombosis: challenges and solutions

    Directory of Open Access Journals (Sweden)

    Reejhsinghani R

    2015-01-01

    Full Text Available Risheen Reejhsinghani, Amir S LotfiDivision of Cardiology, Baystate Medical Center, Springfield, MA, USAAbstract: Stent thrombosis is an uncommon but serious complication which carries with it significant mortality and morbidity. This review analyzes the entity of stent thrombosis from a historical and clinical perspective, and chronicles the evolution of this condition through the various generations of stent development, from bare metal to first-generation, second-generation, and third-generation drug-eluting stents. It also delineates the specific risk factors associated with stent thrombosis and comprehensively examines the literature related to each of these risks. Finally, it highlights the preventative strategies that can be garnered from the existing data, and concludes that a multifactorial approach is necessary to combat the occurrence of stent thrombosis, with higher risk groups, such as patients with ST segment elevation myocardial infarction, meriting further research.Keywords: stent thrombosis, preventative strategies, post-procedural myocardial infarction

  5. A Multicenter, Prospective Study of a New Fully Covered Expandable Metal Biliary Stent for the Palliative Treatment of Malignant Bile Duct Obstruction

    Directory of Open Access Journals (Sweden)

    Bret T. Petersen

    2013-01-01

    Full Text Available Background and Study Aims. Endoscopic placement of self-expanding metal stents (SEMSs is indicated for palliation of inoperable malignant biliary obstruction. A fully covered biliary SEMS (WallFlex Biliary RX Boston Scientific, Natick, USA was assessed for palliation of extrahepatic malignant biliary obstruction. Patients and Methods. 58 patients were included in this prospective, multicenter series conducted under an FDA-approved IDE. Main outcome measurements included (1 absence of stent occlusion within six months or until death, whichever occurred first and (2 technical success, need for reintervention, bilirubin levels, stent patency, time to stent occlusion, and adverse events. Results. Technical success was achieved in 98% (57/58, with demonstrated acute removability in two patients. Adequate clinical palliation until completion of followup was achievedin 98% (54/55 of evaluable patients, with 1 reintervention due to stent obstruction after 142 days. Mean total bilirubin decreased from 8.9 mg/dL to 1.2 mg/dL at 1 month. Device-related adverse events were limited and included 2 cases of cholecystitis. One stent migrated following radiation therapy. Conclusions. The WallFlex Biliary fully covered stent yielded technically successful placement with uncomplicated acute removal where required, appropriate reduction in bilirubin levels, and low rates of stent migration and occlusion. This SEMS allows successful palliation of malignant extrahepatic biliary obstruction.

  6. The recoil proton polarization in. pi. p elastic scattering

    Energy Technology Data Exchange (ETDEWEB)

    Seftor, C.J.

    1988-09-01

    The polarization of the recoil proton for ..pi../sup +/p and ..pi../sup -/p elastic scattering has been measured for various angles at 547 MeV/c and 625 MeV/c by a collaboration involving The George Washington University; the University of California, Los Angeles; and Abilene Christian University. The experiment was performed at the P/sup 3/ East experimental area of the Los Alamos Meson Physics Facility. Beam intensities varied from 0.4 to 1.0 x 10/sup 7/ ..pi../sup -/'s/sec and from 3.0 to 10.0 x 10/sup 7/ ..pi../sup +/'s/sec. The beam spot size at the target was 1 cm in the horizontal direction by 2.5 cm in the vertical direction. A liquid-hydrogen target was used in a flask 5.7 cm in diameter and 10 cm high. The scattered pion and recoil proton were detected in coincidence using the Large Acceptance Spectrometer (LAS) to detect and momentum analyze the pions and the JANUS recoil proton polarimeter to detect and measure the polarization of the protons. Results from this experiment are compared with previous measurements of the polarization, with analyzing power data previously taken by this group, and to partial-wave analysis predictions. 12 refs., 53 figs., 18 tabs.

  7. Anatomy of the Binary Black Hole Recoil: A Multipolar Analysis

    Science.gov (United States)

    Schnittman, Jeremy; Buonanno, Alessandra; vanMeter, James R.; Baker, John G.; Boggs, William D.; Centrella, Joan; Kelly, Bernard J.; McWilliams, Sean T.

    2007-01-01

    We present a multipolar analysis of the recoil velocity computed in recent numerical simulations of binary black hole coalescence, for both unequal masses and non-zero, non-precessing spins. We show that multipole moments up to and including 1 = 4 are sufficient to accurately reproduce the final recoil velocity (= 98%) and that only a few dominant modes contribute significantly to it (2 95%). We describe how the relative amplitude, and more importantly, the relative phase, of these few modes control the way in which the recoil builds up throughout the inspiral, merger, and ring-down phases. We also find that the numerical results can be reproduced, to a high level of accuracy, by an effective Newtonian formula for the multipole moments obtained by replacing in the Newtonian formula the radial separation with an effective radius computed from the numerical data. Beyond the merger, the numerical results are reproduced by a superposition of three Kerr quasi-normal modes. Analytic formulae, obtained by expressing the multipole moments in terms of the fundamental QNMs of a Kerr BH, are able to explain the onset and amount of '.anti-kick" for each of the simulations. Lastly, we apply this multipolar analysis to understand the remarkable difference between the amplitudes of planar and non-planar kicks for equal-mass spinning black holes.

  8. Perturbative corrections to zero recoil inclusive B decay sum rules

    CERN Document Server

    Kapustin, A A; Wise, M B; Grinstein, B; Kapustin, Anton; Ligeti, Zoltan; Wise, Mark B; Grinstein, Benjamin

    1996-01-01

    Comparing the result of inserting a complete set of physical states in a time ordered product of b decay currents with the operator product expansion gives a class of zero recoil sum rules. They sum over physical states with excitation energies less than \\Delta, where \\Delta is much greater than the QCD scale and much less than the heavy charm and bottom quark masses. These sum rules have been used to derive an upper bound on the zero recoil limit of the B\\to D^* form-factor, and on the matrix element of the kinetic energy operator between B meson states. Perturbative corrections to the sum rules of order \\alpha_s(\\Delta) \\Delta^2/m_{c,b}^2 have previously been computed. We calculate the corrections of order \\alpha_s(\\Delta) and \\alpha_s^2(\\Delta) \\beta_0 keeping all orders in \\Delta/m_{c,b}, and show that these perturbative QCD corrections suppressed by powers of \\Delta/m_{c,b} significantly weaken the upper bound on the zero recoil B\\to D^* form-factor, and also on the kinetic energy operator's matrix eleme...

  9. Recoiling Black Holes: Electromagnetic Signatures, Candidates, and Astrophysical Implications

    Directory of Open Access Journals (Sweden)

    S. Komossa

    2012-01-01

    Full Text Available Supermassive black holes (SMBHs may not always reside right at the centers of their host galaxies. This is a prediction of numerical relativity simulations, which imply that the newly formed single SMBH, after binary coalescence in a galaxy merger, can receive kick velocities up to several 1000 km/s due to anisotropic emission of gravitational waves. Long-lived oscillations of the SMBHs in galaxy cores, and in rare cases even SMBH ejections from their host galaxies, are the consequence. Observationally, accreting recoiling SMBHs would appear as quasars spatially and/or kinematically offset from their host galaxies. The presence of the “kicks” has a wide range of astrophysical implications which only now are beginning to be explored, including consequences for black hole and galaxy assembly at the epoch of structure formation, black hole feeding, and unified models of active galactic nuclei (AGN. Here, we review the observational signatures of recoiling SMBHs and the properties of the first candidates which have emerged, including follow-up studies of the candidate recoiling SMBH of SDSSJ092712.65+294344.0.

  10. Endourological Management of Forgotten Encrusted Ureteral Stents

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    Kusuma V. R. Murthy

    2010-08-01

    Full Text Available PURPOSE: To present our experience and discuss the various endourological approaches for treating forgotten encrusted ureteral stents associated with stone formation. MATERIALS AND METHODS: From July 2006 to December 2008, 14 patients (11 men and 3 women with encrusted ureteral stents were analyzed. The average indwelling time of the stent was 4.9 years (range 1 to 12. Plain-film radiography was used to evaluate encrustation, stone burden, and fragmentation of the stents. Intravenous urogram and a Tc99m diethylene triamine penta acetic-acid renogram was used to assess renal function. RESULTS: In seven patients, the entire stent was encrusted, in three patients the encrustation was confined to the ureteral and lower coil part of the stent, two patients had encrustation of the lower coil, and minimal encrustation was observed in two patients. Percutaneous nephrolithotomy was performed in 5 cases and retrograde ureteroscopy with intra-corporeal lithotripsy in 9 patients. Cystolithotripsy was used to manage the distal coil of the encrusted stent in eight patients. Simple cystoscopic removal of the stents with minimal encrustation was carried-out in two cases. Looposcopy and removal of the stent was performed in one patient with an ileal conduit and retained stent. Only one patient required open surgical removal of the stent. Thirteen out of 14 patients were rendered stone and stent free in one session. All except two stents were removed intact and stone analysis of encrustation and calcification revealed calcium oxalate and calcium phosphate in the majority of the cases. CONCLUSION: Endourological management of forgotten encrusted stents is highly successful and often avoids the need for open surgical techniques.

  11. Drug eluting biliary stents to decrease stent failure rates: Areview of the literature

    Institute of Scientific and Technical Information of China (English)

    2016-01-01

    Biliary stenting is clinically effective in relieving bothmalignant and non-malignant obstructions. However, thereare high failure rates associated with tumor ingrowth andepithelial overgrowth as well as internally from biofilmdevelopment and subsequent clogging. Within the lastdecade, the use of prophylactic drug eluting stents as ameans to reduce stent failure has been investigated. Inthis review we provide an overview of the current researchon drug eluting biliary stents. While there is limited humantrial data regarding the clinical benefit of drug elutingbiliary stents in preventing stent obstruction, recentresearch suggests promise regarding their safety andpotential efficacy.

  12. Comparison of short- and mid-term outcomes between CYPHER and TAXUS stents in patients with complex lesions of the coronary arteries

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Background Drug-eluting stent (DES) could obviously reduce in-stent restenosis, which has been proved by international multi-center clinical trials. However, the types of the lesions for stenting were highly selected in these trials. Up to now, there has been no large scale study on the effect of DES in treating complex lesions in real world. Although REALITY trial was just reported during American College of Cardiology Congress 2005, the entry criteria for lesions were limited to one or two de novo lesions. This study was conducted to compare the short- and mid-term clinical outcomes between sirolimus-eluting stent (CYPHER stent) and paclitaxel-eluting stent (TAXUS stent) in patients with complex lesion. Methods This is a retrospective study. From April 2002 to June 2004, a total of 1061 patients were treated with DES in Fu Wai Hospital, of which, 611 patients (642 lesions with 698 CYPHER stents) were in CYPHER group,and 450 patients (534 lesions with 600 TAXUS stents) were in TAXUS group. There was no significant difference in clinical data and lesion types between CYPHER group and TAXUS group. Results Success rates of stent implantation were 99.2% and 98.8% in CYPHER and TAXUS stent groups respectively. The major adverse cardiac events (MACE) during in-hospital and 6-8-month follow-up were 0.7% and 2.3% in CYPHER stent group versus 1.3% and 3.2% in TAXUS stent group. There was no significant difference in MACE rate between these two groups. Restenosis rate was a little higher in TAXUS stent group than that in CYPHER stent group (14.0% vs 7.3%), but there was no significant difference. The incidence of acute occlusion of side branch after implanting DES in main vessel was 6.9% in CYPHER group and 11.9% in TAXUS group(P<0.05).Conclusions CYPHER and TAXUS DES were safe and effective in patients with complex lesion. Clinical outcomes of CYPHER stent were better than TAXUS stent in bifurcation lesions. There was an increasing tendency in restenosis rate and late

  13. An in Vitro Twist Fatigue Test of Fabric Stent-Grafts Supported by Z-Stents vs. Ringed Stents

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    Jing Lin

    2016-02-01

    Full Text Available Whereas buckling can cause type III endoleaks, long-term twisting of a stent-graft was investigated here as a mechanism leading to type V endoleak or endotension. Two experimental device designs supported with Z-stents having strut angles of 35° or 45° were compared to a ringed control under accelerated twisting. Damage to each device was assessed and compared after different durations of twisting, with focus on damage that may allow leakage. Stent-grafts with 35° Z-stents had the most severe distortion and damage to the graft fabric. The 45° Z-stents caused less fabric damage. However, consistent stretching was still seen around the holes for sutures, which attach the stents to the graft fabric. Larger holes may become channels for fluid percolation through the wall. The ringed stent-graft had the least damage observed. Stent apexes with sharp angles appear to be responsible for major damage to the fabrics. Device manufacturers should consider stent apex angle when designing stent-grafts, and ensure their devices are resistant to twisting.

  14. Percutaneous unilateral biliary metallic stent placement in patients with malignant obstruction of the biliary hila and contralateral portal vein steno-occlusion

    Energy Technology Data Exchange (ETDEWEB)

    Son, Rak Chae; Gwon, Dong Il; Ko, Heung Kyu; Kim, Jong Woo; Ko, Gi Young [Dept. of Radiology and Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul (Korea, Republic of)

    2015-06-15

    To investigate the outcomes of percutaneous unilateral metallic stent placement in patients with a malignant obstruction of the biliary hila and a contralateral portal vein steno-occlusion. Sixty patients with a malignant hilar obstruction and unilobar portal vein steno-occlusion caused by tumor invasion or preoperative portal vein embolization were enrolled in this retrospective study from October 2010 to October 2013. All patients were treated with percutaneous placement of a biliary metallic stent, including expanded polytetrafluoroethylene (ePTFE)-covered stents in 27 patients and uncovered stents in 33 patients. A total of 70 stents were successfully placed in 60 patients. Procedural-related minor complications, including self-limiting hemobilia (n = 2) and cholangitis (n = 4) occurred in six (10%) patients. Acute cholecystitis occurred in two patients. Successful internal drainage was achieved in 54 (90%) of the 60 patients. According to a Kaplan-Meier analysis, median survival time was 210 days (95% confidence interval [CI], 135-284 days), and median stent patency time was 133 days (95% CI, 94-171 days). No significant difference in stent patency was observed between covered and uncovered stents (p = 0.646). Stent dysfunction occurred in 16 (29.6%) of 54 patients after a mean of 159 days (range, 65-321 days). Unilateral placement of ePTFE-covered and uncovered stents in the hepatic lobe with a patent portal vein is a safe and effective method for palliative treatment of patients with a contralateral portal vein steno-occlusion caused by an advanced hilar malignancy or portal vein embolization. No significant difference in stent patency was detected between covered and uncovered metallic stents.

  15. Inelastic frontier: Discovering dark matter at high recoil energy

    Science.gov (United States)

    Bramante, Joseph; Fox, Patrick J.; Kribs, Graham D.; Martin, Adam

    2016-12-01

    There exist well-motivated models of particle dark matter which predominantly scatter inelastically off nuclei in direct detection experiments. This inelastic transition causes the dark matter to upscatter in terrestrial experiments into an excited state up to 550 keV heavier than the dark matter itself. An inelastic transition of this size is highly suppressed by both kinematics and nuclear form factors. In this paper, we extend previous studies of inelastic dark matter to determine the present bounds on the scattering cross section and the prospects for improvements in sensitivity. Three scenarios provide illustrative examples: nearly pure Higgsino supersymmetric dark matter, magnetic inelastic dark matter, and inelastic models with dark photon exchange. We determine the elastic scattering rate (through loop diagrams involving the heavy state) as well as verify that exothermic transitions are negligible (in the parameter space we consider). Presently, the strongest bounds on the cross section are from xenon at LUX-PandaX (when the mass splitting δ ≲160 keV ), iodine at PICO (when 160 ≲δ ≲300 keV ), and tungsten at CRESST (when δ ≳300 keV ). Amusingly, once δ ≳200 keV , weak scale (and larger) dark matter-nucleon scattering cross sections are allowed. The relative competitiveness of these diverse experiments is governed by the upper bound on the recoil energies employed by each experiment, as well as strong sensitivity to the mass of the heaviest element in the detector. Several implications, including sizable recoil energy-dependent annual modulation and improvements for future experiments, are discussed. We show that the xenon experiments can improve on the PICO results, if they were to analyze their existing data over a larger range of recoil energies, i.e., 20-500 keV Intriguingly, CRESST has reported several events in the recoil energy range 45-100 keV that, if interpreted as dark matter scattering, is compatible with δ ˜200 keV and an

  16. A Study of Nuclear Recoil Backgrounds in Dark Matter Detectors

    Energy Technology Data Exchange (ETDEWEB)

    Westerdale, Shawn S. [Princeton U.

    2016-01-01

    Despite the great success of the Standard Model of particle physics, a preponderance of astrophysical evidence suggests that it cannot explain most of the matter in the universe. This so-called dark matter has eluded direct detection, though many theoretical extensions to the Standard Model predict the existence of particles with a mass on the $1-1000$ GeV scale that interact only via the weak nuclear force. Particles in this class are referred to as Weakly Interacting Massive Particles (WIMPs), and their high masses and low scattering cross sections make them viable dark matter candidates. The rarity of WIMP-nucleus interactions makes them challenging to detect: any background can mask the signal they produce. Background rejection is therefore a major problem in dark matter detection. Many experiments greatly reduce their backgrounds by employing techniques to reject electron recoils. However, nuclear recoil backgrounds, which produce signals similar to what we expect from WIMPs, remain problematic. There are two primary sources of such backgrounds: surface backgrounds and neutron recoils. Surface backgrounds result from radioactivity on the inner surfaces of the detector sending recoiling nuclei into the detector. These backgrounds can be removed with fiducial cuts, at some cost to the experiment's exposure. In this dissertation we briefly discuss a novel technique for rejecting these events based on signals they make in the wavelength shifter coating on the inner surfaces of some detectors. Neutron recoils result from neutrons scattering from nuclei in the detector. These backgrounds may produce a signal identical to what we expect from WIMPs and are extensively discussed here. We additionally present a new tool for calculating ($\\alpha$, n)yields in various materials. We introduce the concept of a neutron veto system designed to shield against, measure, and provide an anti-coincidence veto signal for background neutrons. We discuss the research and

  17. MR Angiography of Peripheral Arterial Stents: In Vitro Evaluation of 22 Different Stent Types

    Directory of Open Access Journals (Sweden)

    Matthias C. Burg

    2011-01-01

    Full Text Available Purpose. To evaluate stent lumen visibility of a large sample of different peripheral arterial (iliac, renal, carotid stents using magnetic resonance angiography in vitro. Materials and Methods. 21 different stents and one stentgraft (10 nitinol, 7 316L, 2 tantalum, 1 cobalt superalloy, 1 PET + cobalt superalloy, and 1 platinum alloy were examined in a vessel phantom (vessel diameters ranging from 5 to 13 mm filled with a solution of Gd-DTPA. Stents were imaged at 1.5 Tesla using a T1-weighted 3D spoiled gradient-echo sequence. Image analysis was performed measuring three categories: Signal intensity in the stent lumen, lumen visibility of the stented lumen, and homogeneity of the stented lumen. The results were classified using a 3-point scale (good, intermediate, and poor results. Results. 7 stents showed good MR lumen visibility (4x nitinol, 2x tantalum, and 1x cobalt superalloy. 9 stents showed intermediate results (5x nitinol, 2x 316L, 1x PET + cobalt superalloy, and 1x platinum alloy and 6 stents showed poor results (1x nitinol, and 5x 316L. Conclusion. Stent lumen visibility varies depending on the stent material and type. Some products show good lumen visibility which may allow the detection of stenoses inside the lumen, while other products cause artifacts which prevent reliable evaluation of the stent lumen with this technique.

  18. An Evaluation of Magneto Rheological Dampers for Controlling Gun Recoil Dynamics

    Directory of Open Access Journals (Sweden)

    Mehdi Ahmadian

    2001-01-01

    Full Text Available The application of magneto rheological dampers for controlling recoil dynamics is examined, using a recoil demonstrator that includes a single-shot 50 caliber BMG rifle action and a MR damper. The demonstrator is selected such that it can adequately represent the velocities that commonly occur in weapons with a recoil system, and can be used for collecting data for analyzing the effects of MR dampers on recoil dynamics. The MR damper is designed so that it can work effectively at the large velocities commonly occurring in gun recoil, and also be easily adjusted to reasonably optimize the damper performance for the recoil demonstrator. The test results show that it is indeed possible to design and use MR dampers for recoil applications, which subject the damper to relative velocities far larger than the applications that such dampers have commonly been used for (i.e., vehicle applications. Further, the results indicate that the recoil force increases and the recoil stroke decreases nonlinearly with an increase in the damping force. Also of significance is the fact that the adjustability of MR dampers can be used in a closed-loop system such that the large recoil forces that commonly occur upon firing the gun are avoided and, simultaneously, the recoil stroke is reduced. This study points to the need for several areas of research including establishing the performance capabilities for MR dampers for gun recoil applications in an exact manner, and the potential use of such dampers for a fire out of battery recoil system.

  19. Polymeric Biodegradable Stent Insertion in the Esophagus

    Directory of Open Access Journals (Sweden)

    Kai Yang

    2016-04-01

    Full Text Available Esophageal stent insertion has been used as a well-accepted and effective alternative to manage and improve the quality of life for patients diagnosed with esophageal diseases and disorders. Current stents are either permanent or temporary and are fabricated from either metal or plastic. The partially covered self-expanding metal stent (SEMS has a firm anchoring effect and prevent stent migration, however, the hyperplastic tissue reaction cause stent restenosis and make it difficult to remove. A fully covered SEMS and self-expanding plastic stent (SEPS reduced reactive hyperplasia but has a high migration rate. The main advantage that polymeric biodegradable stents (BDSs have over metal or plastic stents is that removal is not require and reduce the need for repeated stent insertion. But the slightly lower radial force of BDS may be its main shortcoming and a post-implant problem. Thus, strengthening support of BDS is a content of the research in the future. BDSs are often temporarily effective in esophageal stricture to relieve dysphagia. In the future, it can be expect that biodegradable drug-eluting stents (DES will be available to treat benign esophageal stricture, perforations or leaks with additional use as palliative modalities for treating malignant esophageal stricture, as the bridge to surgery or to maintain luminal patency during neoadjuvant chemoradiation.

  20. 支架内再狭窄的机制及防治进展%Mechanism of In-stent Restenosis and Progress of the Prevention and Treatment

    Institute of Scientific and Technical Information of China (English)

    刘雯

    2012-01-01

    In-stent restenosis is an important medical problem of coronary atherosclerotic heart disease ( coronary disease for short intervention. Its main mechanism includes: elastic recoil of vessels, formation of thrombus,hyperplasia of smooth muscle and inflammatory reaction and so on. According to the main mechanism there are several methods to prevent stent restenosis including antiplatelet drugs,drug-eluting stents and new material stents and so on. Here is to summarize the main mechanism and the progress of prevention and treatment of in-stent restenosis.%支架内再狭窄是冠状动脉粥样硬化性心脏病介入治疗技术中面临的重要医学难题.目前研究其主要发生机制有血管弹性回缩、血栓形成、平滑肌过度增生和炎性反应等.针对其主要机制的防治支架内再狭窄的方法有抗血小板药物的使用、药物涂层支架的使用和新型材料支架的使用等.现就支架内再狭窄发生机制及防治进展予以综述.

  1. Carotid Artery Stenting Successfully Prevents Progressive Stroke Due to Mobile Plaque

    Directory of Open Access Journals (Sweden)

    Masahiro Oomura

    2015-05-01

    Full Text Available We report a case of progressive ischemic stroke due to a mobile plaque, in which carotid artery stenting successfully prevented further infarctions. A 78-year-old man developed acute multiple infarcts in the right hemisphere, and a duplex ultrasound showed a mobile plaque involving the bifurcation of the left common carotid artery. Maximal medical therapy failed to prevent further infarcts, and the number of infarcts increased with his neurological deterioration. Our present case suggests that the deployment of a closed-cell stent is effective to prevent the progression of the ischemic stroke due to the mobile plaque.

  2. Endovascular stent graft for treatment of complicated spontaneous dissection of celiac artery: Report of two cases

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Ung Rae; Lee, Young Hwan [Dept. of Diagnostic Radiology, Catholic University of Daegu School of Medicine, Daegu (Korea, Republic of); Kim, Young Hwan [Dept. of Diagnostic Radiology, Dongsan Medical Center, Keimyung University School of Medicine, Daegu (Korea, Republic of)

    2013-06-15

    We report 2 cases of complicated spontaneous dissection of the celiac artery, which were successfully treated by a stent graft. The first patient was a 47-year-old man who presented with acute abdominal pain. CT scan showed ruptured saccular aneurysm with surrounding retroperitoneal hematoma. The second patient was a 57-year-old man with progressive dissecting aneurysm. Endovascular stent graft was placed in the celiac trunk to control bleeding, and to prevent rupture in each patient. Follow-up CT scans showed complete obliteration of a dissecting aneurysm.

  3. Successful retrieval of an unexpanded coronary stent from the left main coronary artery during primary percutaneous coronary intervention

    Directory of Open Access Journals (Sweden)

    Šalinger-Martinović Sonja

    2011-01-01

    Full Text Available Introduction. Dislodgement and embolization of the new generation of coronary stents before their deployment are rare but could constitute a very serious complication. Case Outline. We report a case of a stent dislodgement into the left main coronary artery during the primary coronary intervention of infarct related left circumflex artery in a patient with acute myocardial infarction. The dislodged and unexpanded bare-metal stent FlexMaster 3.0x19 mm (Abbot Vascular was stranded and bended in the left main coronary artery (LMCA, probably by the tip of the guiding catheter, but stayed over the guidewire. It was successfully retrieved using a low-profile Ryujin 1.25x15 balloon catheter (Terumo that was passed through the stent, inflated and then pulled back into the guiding catheter. After that, the whole system was withdrawn through the 6 F arterial sheath via the transfemoral approach. After repeated cannulation via the 6F arterial sheath, additional BMW and ATW guidewires were introduced into the posterolateral and obtuse marginal branches and a bare-metal stent Driver (Medtronic Cardiovascular Inc 3.0x18 mm was implanted in the target lesion. Conclusion. Stent dislodgement is a rare but potentially life-threatening complication of the percutaneous coronary intervention. This incident occurring in the LMCA in particular during an acute myocardial infarction requires to be urgently resolved. The avoidance of rough manipulation with the guiding catheter and delivery system may help in preventing this kind of complications.

  4. Evaluation of a novel stent technology: the Genous EPC capturing stent

    NARCIS (Netherlands)

    M. Klomp

    2012-01-01

    Tegenwoordig gebruiken ziekenhuizen een nieuwe stent bij dotterbehandelingen van kransslagadervernauwingen. Deze Genous-stent heeft een laag met antistoffen waardoor het behandelde bloedvat snel bedekt raakt met lichaamseigen cellen. Zo wordt tegengegaan dat er opnieuw een vernauwing optreedt of dat

  5. Carotid artery stent continued expansion days after deployment, without post stent deployment angioplasty

    Directory of Open Access Journals (Sweden)

    Umair Qazi

    2015-10-01

    Full Text Available This is a carotid artery stent (CAS case report, which avoids post-stent deployment angioplasty (Post-SDA, with duplex confirmed continued stent expansion at 1, 3 and 30-day post deployment. This report confirms that self-expanding nitinol stents in the carotid artery may not require Post-SDA. We believe CAS can be performed without Post-SDA, which helps reduce the occurrence of intraoperative hemodynamic depression.

  6. Influence of strut cross-section of stents on local hemodynamics in stented arteries

    Science.gov (United States)

    Jiang, Yongfei; Zhang, Jun; Zhao, Wanhua

    2016-05-01

    Stenting is a very effective treatment for stenotic vascular diseases, but vascular geometries altered by stent implantation may lead to flow disturbances which play an important role in the initiation and progression of restenosis, especially in the near wall in stented arterial regions. So stent designs have become one of the indispensable factors needed to be considered for reducing the flow disturbances. In this paper, the structural designs of strut cross-section are considered as an aspect of stent designs to be studied in details. Six virtual stents with different strut cross-section are designed for deployments in the same ideal arterial model. Computational fluid dynamics (CFD) methods are performed to study how the shape and the aspect ratio (AR) of strut cross-section modified the local hemodynamics in the stented segments. The results indicate that stents with different strut cross-sections have different influence on the hemodynamics. Stents with streamlined cross-sectional struts for circular arc or elliptical arc can significantly enhance wall shear stress (WSS) in the stented segments, and reduce the flow disturbances around stent struts. The performances of stents with streamlined cross-sectional struts are better than that of stents with non-streamlined cross-sectional struts for rectangle. The results also show that stents with a larger AR cross-section are more conductive to improve the blood flow. The present study provides an understanding of the flow physics in the vicinity of stent struts and indicates that the shape and AR of strut cross-section ought to be considered as important factors to minimize flow disturbance in stent designs.

  7. Safety, efficacy and costs associated with direct coronary stenting compared with stenting after predilatation

    Science.gov (United States)

    IJsselmuiden, A.; Serruys, P.W.; Tangelder, G.J.; Slagboom, T.; van der Wieken, R.; Kiemeneij, F.; Laarman, G.J.

    2004-01-01

    Objectives Comparison of the in-hospital success rates, procedural costs and short-term clinical outcomes of direct stenting versus stenting after balloon predilatation. Methods Altogether, 400 patients with angina pectoris and/or myocardial ischaemia due to coronary stenoses in a single native vessel were randomised to either direct stenting or stenting after predilatation. Baseline characteristics were evenly distributed between the two groups. Results Procedural success rates were similar (96.0% direct stenting group vs. 94.5% predilatation) as well as final successful stent implantation (98.3 vs. 97.8%), while the primary success rate of direct stenting alone was 88.3%, p=0.01. In multivariate analysis, angiographic lesion calcification was an independent predictor of unsuccessful direct stenting (odds ratio 7.1, 95% confidence interval 2.8-18.2, p0.15 μg/l, used as a measure of distal embolisation, were similar in both groups (17.8 vs. 17.1%). Rates of major adverse cardiac events at 30 days were 4.5% in the direct stenting group versus 5.5% in the predilated group (ns). Direct stenting was associated with savings in fluoroscopy time, and angiographic contrast agent use, and a reduction in utilisation of angioplasty balloons (0.4 vs. 1.17 balloons per patient, p<0.001). Mean per patient procedural costs associated with direct stenting versus predilatation were €2545±914 versus €2763±842 (p=0.01), despite the implantation of more stents in the directly stented group. Conclusion Compared with a strategy of stenting preceded by balloon predilatation, direct stenting was equally safe and effective, with similar in-hospital and 30-day clinical outcomes, and modest procedural cost-savings. A calcified lesion predicted unsuccessful direct stenting. PMID:25696356

  8. The Electron Recoil Response of the XENON1T Dark Matter Experiment

    Science.gov (United States)

    Shockley, Evan; Xenon1T Collaboration

    2017-01-01

    XENON1T employs a two-phase xenon TPC to search for dark matter by detecting scintillation light produced by nuclear recoils in a 2 ton active volume of liquid xenon. However, nuclear recoils are not the only recoils that can occur since radiogenic electronic recoils are possible. Our only way of differentiating nuclear and electronic recoils is by comparing the relative fraction of scintillation (S1) and ionization (S2) signals. For the first Science Run of XENON1T, we must understand the response of our detector to S1 and S2 signals at the low keV energies where dark matter will present itself. Therefore, I will be discussing the current understanding of our signal and detection mechanisms at these energies. This work includes work using sources such as the Rn220 technique developed by XENON collaborators for understanding our rejection of electronic recoils.

  9. Review of stents for the carotid artery.

    Science.gov (United States)

    Bosiers, M; Deloose, K; Verbist, J; Peeters, P

    2006-04-01

    The individual characteristics of a stent may make it an attractive choice in some circumstances, but render it a less desirable option in others. The applicability depends primarily on the arterial anatomy and the specific details of the lesion being treated. A careful assessment by the interventionalist is required to select the proper type of stent that is of appropriate size. Certainly, personal preferences and familiarity with a specific device may legitimately influence the decision to choose one stent over another. Finally, stent design can play a role in the selection procedure. Although carotid stents are often functionally equivalent in the clinical setting and have been used successfully to treat a wide variety of lesions, a basic knowledge of stent geometry can contribute to make up your mind in certain carotid cases.

  10. Esophageal stent migration leads to intestinal obstruction

    Directory of Open Access Journals (Sweden)

    Oguzhan Karatepe

    2009-07-01

    Full Text Available Background: Self-expanding metallic stents are the devices of choice in the treatment of malign or benign strictures of esophagus. Stent migration is a well-known complication of this procedure. Aims: We report a case of intestinal obstruction caused by esophageal stent migration, in which surgical intervention was used. Methods: A 65-year-old woman, who had a medical history of gastric cancer operation and esophageal stent application admitted to our emergeny department with a 48-hour history of abdominal pain, nausea and vomiting. An emergeny laparotomy was performed and the migrated stent leading to intestinal obstruction was removed. Results: The patient recovered without incident and was discharged on postoperative day 3. Conclusion: This case illustrates that esophageal stent migration has to be considered as a potential life-threatening complication.

  11. Rapid virtual stenting for intracranial aneurysms

    Science.gov (United States)

    Zhao, Liang; Chen, Danyang; Chen, Zihe; Wang, Xiangyu; Paliwal, Nikhil; Xiang, Jianping; Meng, Hui; Corso, Jason J.; Xu, Jinhui

    2016-03-01

    The rupture of Intracranial Aneurysms is the most severe form of stroke with high rates of mortality and disability. One of its primary treatments is to use stent or Flow Diverter to divert the blood flow away from the IA in a minimal invasive manner. To optimize such treatments, it is desirable to provide an automatic tool for virtual stenting before its actual implantation. In this paper, we propose a novel method, called ball-sweeping, for rapid virtual stenting. Our method sweeps a maximum inscribed sphere through the aneurysmal region of the vessel and directly generates a stent surface touching the vessel wall without needing to iteratively grow a deformable stent surface. Our resulting stent mesh has guaranteed smoothness and variable pore density to achieve an enhanced occlusion performance. Comparing to existing methods, our technique is computationally much more efficient.

  12. Quenching Factor for Low Energy Nuclear Recoils in a Plastic Scintillator

    OpenAIRE

    Reichhart, L.; Akimov, D. Yu.; Araujo, H. M.; Barnes, E. J.; Belov, V. A.; Burenkov, A. A.; Chepel, V.; Currie, A; DeViveiros, L.; Edwards, B.; Francis, V.; Ghag, C.; Hollingsworth, A.; Horn, M.; Kalmus, G.E.

    2011-01-01

    Plastic scintillators are widely used in industry, medicine and scientific research, including nuclear and particle physics. Although one of their most common applications is in neutron detection, experimental data on their response to low-energy nuclear recoils are scarce. Here, the relative scintillation efficiency for neutron-induced nuclear recoils in a polystyrene-based plastic scintillator (UPS-923A) is presented, exploring recoil energies between 125 keV and 850 keV. Monte Carlo simula...

  13. Recoil ion charge state distribution following the beta(sup +) decay of {sup 21}Na

    Energy Technology Data Exchange (ETDEWEB)

    Scielzo, Nicholas D.; Freedman, Stuart J.; Fujikawa, Brian K.; Vetter, Paul A.

    2003-01-03

    The charge state distribution following the positron decay of 21Na has been measured, with a larger than expected fraction of the daughter 21Ne in positive charge states. No dependence on either the positron or recoil nucleus energy is observed. The data is compared to a simple model based on the sudden approximation. Calculations suggest a small but important contribution from recoil ionization has important consequences for precision beta decay correlation experiments detecting recoil ions.

  14. Mechanical behavior of peripheral stents and stent-vessel interaction: A computational study

    Science.gov (United States)

    Dottori, Serena; Flamini, Vittoria; Vairo, Giuseppe

    2016-05-01

    In this paper stents employed to treat peripheral artery disease are analyzed through a three-dimensional finite-element approach, based on a large-strain and large-displacement formulation. Aiming to evaluate the influence of some stent design parameters on stent mechanics and on the biomechanical interaction between stent and arterial wall, quasi-static and dynamic numerical analyses are carried out by referring to computational models of commercially and noncommercially available versions of both braided self-expandable stents and balloon-expandable stents. Addressing isolated device models, opening mechanisms and flexibility of both opened and closed stent configurations are numerically experienced. Moreover, stent deployment into a stenotic peripheral artery and possible postdilatation angioplasty (the latter for the self-expandable device only) are simulated by considering different idealized vessel geometries and accounting for the presence of a stenotic plaque. Proposed results highlight important differences in the mechanical response of the two types of stents, as well as a significant influence of the vessel shape on the stress distributions arising upon the artery-plaque system. Finally, computational results are used to assess both the stent mechanical performance and the effectiveness of the stenting treatment, allowing also to identify possible critical conditions affecting the risk of stent fracture, tissue damage, and/or pathological tissue response.

  15. Hypersensitivity to drug-eluting stent and stent thrombosis: Kounis or not Kounis syndrome?

    Institute of Scientific and Technical Information of China (English)

    TAN Wei; CHENG Kang-lin; CHEN Qiu-xiong

    2009-01-01

    @@ With the utilization of coronary-stents, coronary remodeling and restenosis were reduced compared with balloon angioplasty alone.~1 However, the risk of restenosis is still in the range of 15% to 20%. Drug-eluting stents (DES), which could release antiproliferative pharmacological agents after deployment. were designed to inhibit the response to injury reaction after bare-metal stent (BMS) implantation.

  16. Removal of retrievable self-expandable urethral stents: experience in 58 stents

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Ji Hoon; Song, Ho-Young; Kim, Jin Hyoung; Ko, Heung-Kyu; Kim, Yong Jae; Woo, Chul-Woong; Kim, Tae-Hyung; Ko, Gi-Young; Yoon, Hyun-Ki; Sung, Kyu-Bo [Asan Medical Center, Department of Radiology and Research Institute of Radiology, University of Ulsan College of Medicine, Seoul (Korea); Park, Hyungkeun [Asan Medical Center, Department of Urology, University of Ulsan College of Medicine, Seoul (Korea)

    2006-09-15

    The purpose of this study was to retrospectively evaluate the safety and efficacy of removing retrievable self-expandable urethral stents using a retrieval hook wire. Under fluoroscopic guidance, the removal of 58 polyurethane or PTFE (polytetrafluoroethylene)-covered stents was attempted in 33 patients using a retrieval hook wire. Indications for removal were elective removal (n=21), stent migration (n=19), formation of tissue hyperplasia around or inside of the stent (n=14), stent deformity (n=3), and severe pain (n=1). The mean time the stents remained in place was 64.8{+-}42.9 days (range, 1-177 days). Fifty-six (97%) of the 58 stents were successfully removed using the retrieval hook wire despite the following difficulties; hook wire disconnection (n=2), untied drawstrings (n=3), and polyurethane membrane disruption/separation (n=4). The removal procedure using a retrieval hook wire failed in two stents (3%) which had migrated into the urinary bladder. One of the two stents with migration into the urinary bladder was removed using a snare through the cystostomy route. The overall complication rate was 14% (seven hematuria cases and one urethral tear case), and all were minor and spontaneously resolved without further treatment. In conclusion, removal of retrievable urethral stents using a retrieval hook wire was safe and effective despite some technical difficulties. It is a useful method for allowing temporary stent placement and solving various complications of stent use. (orig.)

  17. Stent implantation influence wall shear stress evolution

    Science.gov (United States)

    Bernad, S. I.; Totorean, A. F.; Bosioc, A. I.; Petre, I.; Bernad, E. S.

    2016-06-01

    Local hemodynamic factors are known affect the natural history of the restenosis critically after coronary stenting of atherosclerosis. Stent-induced flows disturbance magnitude dependent directly on the strut design. The impact of flow alterations around struts vary as the strut geometrical parameters change. Our results provide data regarding the hemodynamic parameters for the blood flow in both stenosed and stented coronary artery under physiological conditions, namely wall shear stress and pressure drop.

  18. Assessment of Coronary Stents by 64-slice Computed Tomography:In-stent Lumen Visibility and Patency

    Institute of Scientific and Technical Information of China (English)

    Ling-yan Kong; Zheng-yu Jin; Shu-yang Zhang; Zhu-hua Zhang; Yi-ning Wang; Lan Song; Xiao-na Zhang; Yun-qing Zhang

    2009-01-01

    Objective To assess lumen visibility of coronary stents by 64-slice computed tomography(CT)coronary angiography,and determine the value of 64-slice CT in non-invasive detecting of in-stent restenosis after coronary artery stent implantation.Methods Totally,60 patients(54 males,aged 57.0±12.7 years)and 105 stents were investigated by 64-slice CT at a mean interval of 20.0±16.6 months after coronary stents implantation.Axial multi-planar reconstruction images of the stents and curved-planar reconstruction images through the median of the stents were reconstructed for evaluating stent image quality on a 5-point scale(1=excellent,5=nonassessable),and stent lumen diameter was detected.Conventional coronary angiography was performed in 18 patients,and 32 stents were evaluated.Results Image quality was good to excellent on average(score 1.71±0.76).Stent image quality score was correlated to heart rate(r=0.281,P<0.01)and stent diameter(r=0.480,P<0.001).All the stents were assessable in lumen visibility with an average visible lumen diameter percentage of 60.7% ±13.6% .Visible lumen diameter percentage was correlated to heart rate(r=-0.193,P<0.05),stent diameter (r=0.403,P<0.001),and stent image quality score(r=-0.500,P<0.001).Visible lumen diameter percentage also varied depending on the stent type.In comparison with the conventional coronary angiography,4 of 6 in-stent stenoses were correctly detected.The sensitivity and specificity for the detection of in-stent stenosis were 66.7% and 84.6% ,respectively.Conclusions Using a 64-slice CT,the stent lumen is partly visible in most of the stents.And 64-slice CT may be useful in the assessment of stent patency.

  19. CKM favored semileptonic decays of heavy hadrons at zero recoil

    CERN Document Server

    Yan, T M; Yu, H L; Yan, Tung Mow; Cheng, Hai Yang

    1996-01-01

    We study the properties of Cabibbo-Kobayashi-Maskawa (CKM) favored semileptonic decays of mesons and baryons containing a heavy quark at the point of no recoil. We first use a diagrammatic analysis to rederive the result observed by earlier authors that at this kinematic point the B meson decays via b\\to c transitions can only produce a D or D^* meson. The result is generalized to include photon emissions which violate heavy quark flavor symmetry. We show that photons emitted by the heavy quarks and the charged lepton are the only light particles that can decorate the decays \\bar{B}\\to D(D^*) + \\ell\

  20. Optimum design of control system in recoil mechanisms

    Directory of Open Access Journals (Sweden)

    J. P. Sirpal

    1959-07-01

    Full Text Available The various parameters in the design of a control system in a conventional type of recoil mechanism have been optimized for minimum weight and the ideal form of velocity space variation during runout has been derived. A theoretical analysis for some of the equipments in service reveals that their actual values are very nearly the same as those given by theory except for the ratio l by di which are lower than those theoretically suggested indicating that wide margins of safety against buckling have been used in their design.

  1. B -> D* l nu at zero recoil: an update

    CERN Document Server

    Bailey, Jon A; Bernard, C; Bouchard, C M; DeTar, C; El-Khadra, A X; Freeland, E D; Gámiz, E; Gottlieb, Steven; Heller, U M; Hetrick, J E; Kronfeld, A S; Laiho, J; Levkova, L; Mackenzie, P B; Oktay, M B; Simone, J N; Sugar, R; Toussaint, D; Van de Water, R S

    2010-01-01

    We present an update of our calculation of the form factor for B -> D* l nu at zero recoil, with higher statistics and finer lattices. As before, we use the Fermilab action for b and c quarks, the asqtad staggered action for light valence quarks, and the MILC ensembles for gluons and light quarks (L\\"uscher-Weisz married to 2+1 rooted staggered sea quarks). In this update, we have reduced the total uncertainty on F(1) from 2.6% to 1.7%. At Lattice2010 we presented a still-blinded result, but this writeup includes the unblinded result from the September 2010 CKM workshop.

  2. Is CHF triggered by the vapor recoil effect?

    CERN Document Server

    Nikolayev, Vadim S; Chatain, D

    2007-01-01

    This paper deals with the triggering mechanism of the boiling crisis, a transition from nucleate to film boiling. We observe the boiling crisis in pool saturated boiling experimentally at nearly critical pressure to take advantage of the slowness of the bubble growth and of the smallness of the Critical Heat Flux (CHF) that defines the transition point. Such experiments require the reduced gravity conditions. Close to the CHF, the slow growth of the individual dry spots and their subsequent fusion on the transparent heater are observed through the latter. As discussed in the paper, these observations are consistent with numerical results obtained with the vapor recoil model of the boiling crisis.

  3. Microbeam recoil detection for hydration of minerals studies

    Energy Technology Data Exchange (ETDEWEB)

    Sie, S.H.; Suter, G.F. [CSIRO, North Ryde, NSW (Australia). Exploration and Mining Div.; Chekhmir, A.; Green, T.H. [Macquarie Univ., North Ryde, NSW (Australia)

    1993-12-31

    The glancing angle geometry is chosen to enable application of the elastic recoil detection microanalysis on thick geological samples, for hydrogen content determination. Simultaneous PIXE measurements can be used to eliminate the problem of uncertainties in beam charge collection. The method is applied to determine the hydration characteristics of silicates, produced experimentally at high pressure and temperature simulating the lower crust and upper mantle conditions. Preliminary results show that the technique can be applied readily on a microscopic (<100 {mu}m) scale for determination of H at fraction of atomic percent level. 9 refs., 3 figs.

  4. Nitinol stent design - understanding axial buckling.

    Science.gov (United States)

    McGrath, D J; O'Brien, B; Bruzzi, M; McHugh, P E

    2014-12-01

    Nitinol׳s superelastic properties permit self-expanding stents to be crimped without plastic deformation, but its nonlinear properties can contribute towards stent buckling. This study investigates the axial buckling of a prototype tracheobronchial nitinol stent design during crimping, with the objective of eliminating buckling from the design. To capture the stent buckling mechanism a computational model of a radial force test is simulated, where small geometric defects are introduced to remove symmetry and allow buckling to occur. With the buckling mechanism ascertained, a sensitivity study is carried out to examine the effect that the transitional plateau region of the nitinol loading curve has on stent stability. Results of this analysis are then used to redesign the stent and remove buckling. It is found that the transitional plateau region can have a significant effect on the stability of a stent during crimping, and by reducing the amount of transitional material within the stent hinges during loading the stability of a nitinol stent can be increased.

  5. Stenting:84 Cases of Clinical Application

    Institute of Scientific and Technical Information of China (English)

    GUANG Yongsong

    2002-01-01

    Objective To evaluate clinical application of therapeutic stenting. Methods 84 cases were managed with stents clinically, 136 procedures of intervention in all. The cases were suffering from portal hypertension of cirrhosis, stricture of inferior vana cava, superior vana cava syndrome, post- operative esophageal stricture, narrowig of femoral, common carotid, renal, superior mesentery arteries and biliary tract, etc. Results Therapeutic stenting achieves clinical effects completely different from conventional intemal medicine and surgery. Conclusion Therapeutic stenting is clinically unique, dramatically effective, with minor risks and worthy promoting.

  6. Novel stents for the prevention of restenosis.

    Science.gov (United States)

    McKenna, C J; Holmes, D R; Schwartz, R S

    1997-10-01

    Since the introduction of Interventional Cardiology in 1976, there has been rapid expansion both in its clinical application and the tools of the trade. This growth was accelerated with the introduction of the intra-coronary stent in 1987. The demonstration that stents may reduce the incidence of restenosis after percutaneous coronary revascularization has further stimulated the search for the perfect endovascular prosthesis. By creating a hybrid stent, incorporating natural coatings and local drug delivery in the design, it is hoped that the complications associated with stent thrombosis and restenosis can be eradicated. (Trends Cardiovasc Med 1997;7:245-249). © 1997, Elsevier Science Inc.

  7. Stent Fracture: Case Report and Literature Review

    OpenAIRE

    Lousinha, A; Fiarresga, A; Cardona, L.; Lopes, JP; Lopes, A.; Cacela, D; L. Sousa; Patrício, L; Bernardes, L; Cruz Ferreira, R

    2011-01-01

    Apresentamos o caso de um doente, previamente submetido a angioplastia coronária com um stent revestido com fármaco, com enfarte agudo do miocárdio (EAM) provocado por trombose tardia do stent, tendo sido detectada fractura do mesmo. Este caso vem reforçar o reconhecimento crescente da fractura como potencial mecanismo para a trombose tardia de stent, na era dos stents revestidos com fármaco. A propósito deste caso clínico, apresentamos uma revisão da liter...

  8. 53. Bilateral ductal stenting for nonconfluent pulmonary arteries in a newborn

    Directory of Open Access Journals (Sweden)

    K. Al Dhahri

    2016-07-01

    Full Text Available Bilateral PDA dependent pulmonary circulation with right and left pulmonary artery discontinuity is very rare. Limited data available for bilateral PDA stenting. Bilateral PDA stenting in nonconfluent pulmonary arteries is challenging procedure but can be considered as an option in the management of complex conditions like this. 12 days old Preterm (36 weeks gestation male baby with birth weight of 2.6 kg developed respiratory distress with severe cyanosis and desaturation upto 50%. Baby was intubated and started on Prostaglandin 0.05 mic/kg/mt. His saturation improved to 80%. Echocardiogram showed complex cyanotic heart disease, Situs ambiguous, dextrocardia, complete unbalanced AV septal defect, pulmonary atresia , nonconfluent small branch pulmonary arteries supplied by the bilateral patent ductus arteriosus (PDA from right aortic arch and all four pulmonary veins form a confluence and drain into superior vena cava(SVC through vertical vein with no obstruction. Baby was taken up for PDA stenting. descending aortogram showed right aortic arch with vertical tortuous duct to right pulmonary artery (RPA and another short duct with acute angle from left subclavian artery to left pulmonary artery (LPA . Both ducti stented with coronary stents. Vertical vein angiogram showed both lungs drain to a confluence and then to SVC via ascending vertical vein with no obstruction. After stenting lung perfusion improved and the baby was stable and maintained 80% saturation on room air. Bilateral PDA dependent pulmonary circulation with right and left pulmonary artery discontinuity is very rare. Our case is unique with Heterotaxy, TAPVC, Dextrocardia and double ducti. Eventhough bilateral ductal stenting is technically challenging it is successful through femoral artery approach.

  9. Treatment of gastric outlet and duodenal obstructions with uncovered expandable metal stents

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    AIM: To investigate and evaluate the technical feasibility and clinical effectiveness of fluoroscopically guided peroral uncovered expandable metal stent placement to treat gastric outlet and duodenal obstructions. METHODS: Fifteen consecutive patients underwent peroral placement of WallstentTM Enteral Endoprosthesis to treat gastric outlet and duodenal obstructions (14 malignant, 1 benign). All procedures were completed under fluoroscopic guidance without endoscopic assistance. Follow-up was completed until the patients died or were lost, and the clinical outcomes were analyzed. RESULTS: The technique success rate was 100%, and the oral intake was maintained in 12 of 14 patients varying from 7 d to 270 d. Two patients remained unable to resume oral intake, although their stents were proven to be patent with the barium study. One patient with acute necrotizing pancreatitis underwent enteral stenting to treat intestinal obstruction, and nausea and vomiting disappeared. Ten patients died during the followup period, and their mean oral intake time was 50 d. No procedure-related complications occurred. Stent migration to the gastric antrum occurred in one patient 1 year after the procedure, a tumor grew at the proximal end of the stent in another patient 38 d post-stent insertion. CONCLUSION: Fluoroscopically guided peroral metal stent implantation is a safe and effective method to treat malignant gastrointestinal obstructions, and complications can be ignored based on our short-term study. Indications for this procedure should be discreetly considered because a few patients may not benefit from gastrointestinal insertion, but some benign gastrointestinal obstructions can be treated using this procedure.

  10. Long-term efficacy and safety of domestic drug-eluting stents in patients with acute coronary syndrom%急性冠脉综合征患者植入国产药物支架的长期疗效和安全性分析

    Institute of Scientific and Technical Information of China (English)

    姚海木; 孙同文; 张晓娟; 万有栋; 付新; 沈德良; 张金盈; 李凌

    2015-01-01

    efficacy and safety of domestic drug-eluting stents (DES) in patients with acute coronary syndrome (ACS) following percutaneous coronary intervention (PCI).Methods All patients with ACS treated with successful PCI from July 2009 to December 2010 were included in this study.Patients were excluded from analysis if they were implanted with bare metal stents or different kinds of stents (domestic and imported DES) simultaneously.Clinical,laboratory,angiographic and procedural data were collected.Clinical follow-up was done through patient visits,telephone interview,and medical record review and adverse cardiac events were recorded.The patients were divided into two groups according to different stents implanted:domestic DES and imported DES.Comparisons between continuous variables were made using the Student t-test or Wilcoxon rank-sum test.Categorical data were tested using x2 test or the Fisher exact test.Multivariate logistic regression analysis was performed to identify independent predictors of events.Cumulative survival curves were constructed using the Kaplan-Meier method and comparisons made using log-rank tests.All statistical analyses were performed using SPSS 17.0 software,and a two-tailed P value of < 0.05 was considered statistically significant.Results (1) There were 1683 patients enrolled in the analysis and 1558 (92.6%) of them were successfully followed-up.Mean follow-up time was (29.1 ±5.9) months.There were 130 (8.3%) cases subjected to major adverse cardiovascular events (MACE),including 32 (2.1%) cases with cardiac death,16 (1%) cases with re-myocardial infarction,and 94 (6%) cases with revascularization.(2) The rates of all cause death,cardiac death,re-infarction,revascularization,in-stent restenosis,in-stent thrombosis and MACE were not significantly different between the two groups (all P > 0.05).(3) Multivariate logistic regression revealed that diabetes mellitus (OR =1.75,95% CI:1.09-2.82,P =0.021),vascular numbers of PCI (OR =2

  11. The Clinicaal and Angiograghic Outcome of 290 Cases after Stent Placement in Small Coronary Vessels

    Institute of Scientific and Technical Information of China (English)

    郭文怡; 贾国良; 李伟杰; 秦涛; 李成祥; 栾荣华; 吕安林; 王小燕; 李媛

    2003-01-01

    Objectives To invest the success procedure,immediate outcome after procedure,the rate of main adverse cardiac events after procedure and restenosis after stent placement in small coronary vessels. Methods 290 patients with selected or emergency stent implantation in small vessels from April, 1997 to March, 2002. Total 299 vessels, 304 lesions and 316 stents were statisted. The successs rate of procedure, immediate outcome after procedure, the rate of main adverse cardiac events after procedure and restenosis after stent placement in small coronary vessels were assessed. The patients were followed up l month to 4 years. Re-catheter angiography were done in 122/290 patients. Results The narrow rate of lesion dropped from 89% ± 12% before procedure to 5% ±5% after procedure (diameter). 202 patients were followed up 1 month(69.7% ). 197/202 cases were survival. 5/202 cases died in 3hrs to 7days. 2/5 cases died of persistent hypotension after procedure. 1/5 case died of acute left heart failure. 2/5 cases died of sudden death. 180 cases were followed up 5 months to 4 years. The non-event survival (NES) rate was 73.3% (132/180). The re-angiography were done in 122 cases. Restenosis happened in 39 cases (30.3%). 37 patients repeated PCI. 2 patients went to CABG. 2 cases got angina recurrence and were proved second time restenosis by re-angiography. The third time PCI was done in 1 patient. The other patients went to CABG. 1 case died of chronic heart failure after 2 years. 1 case suffered acute myocardial infarction on artery stent implanted. Conclusions There are high success rate of procedure and perfect immediate outcome in stent placement in small vessels.Main adverse cardiac events did not increased. Non-event survial was satisfied in long term follow - up.Restenosis rate was showed slightly higher than the one of main vessels.

  12. Intravascular Stenting in Microvascular Anastomoses

    DEFF Research Database (Denmark)

    Assersen, Kristine; Sørensen, Jens

    2015-01-01

    Background The effect of intravascular stenting (IVaS) on microvascular anastomoses has given adverse results. For experienced microsurgeons the benefit of IVaS is doubtful. We have investigated the potential benefit of the IVaS technique for two groups of inexperienced microsurgeons with different...... surgical levels of experience (medical students and young residents). Experienced microsurgeons acted as a control group. Materials and Methods In an experimental crossover study, 139 microsurgical anastomoses were performed on the femoral artery in 70 rats by 10 surgeons. On one side of the rat, the IVaS...... spent on the anastomosis. Results No significant difference in patency rates was seen between the stenting and conventional technique in all three groups. The experienced microsurgeons had 100% patency rate with both techniques. The medical students had 20/28 in the IVaS and 19/28 conventional group...

  13. Aorta Segmentation for Stent Simulation

    CERN Document Server

    Egger, Jan; Setser, Randolph; Renapuraar, Rahul; Biermann, Christina; O'Donnell, Thomas

    2011-01-01

    Simulation of arterial stenting procedures prior to intervention allows for appropriate device selection as well as highlights potential complications. To this end, we present a framework for facilitating virtual aortic stenting from a contrast computer tomography (CT) scan. More specifically, we present a method for both lumen and outer wall segmentation that may be employed in determining both the appropriateness of intervention as well as the selection and localization of the device. The more challenging recovery of the outer wall is based on a novel minimal closure tracking algorithm. Our aortic segmentation method has been validated on over 3000 multiplanar reformatting (MPR) planes from 50 CT angiography data sets yielding a Dice Similarity Coefficient (DSC) of 90.67%.

  14. Delayed cerebral infarction due to stent folding deformation following carotid artery stenting

    Energy Technology Data Exchange (ETDEWEB)

    Seo, Kwon Duk; Lee, Kyung Yul; Suh, Sang Hyun [Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul (Korea, Republic of); Kim, Byung Moon [Dept. of Radiology, Severance Hospital, Yonsei University College of Medicine, Seoul (Korea, Republic of)

    2014-12-15

    We report a case of delayed cerebral infarction due to stent longitudinal folding deformation following carotid artery stenting using a self-expandable stent with an open-cell design. The stented segment of the left common carotid artery was divided into two different lumens by this folding deformation, and the separated lumens became restricted with in-stent thrombosis. Although no established method of managing this rare complication exists, a conservative approach was taken with administration of anticoagulant and dual antiplatelet therapy. No neurological symptoms were observed during several months of clinical follow-up after discharge.

  15. Peri-stent contrast staining, major evaginations and severe malapposition after biolimus-eluting stent implantation

    DEFF Research Database (Denmark)

    Antonsen, Lisbeth; Thayssen, Per; Jensen, Lisette Okkels

    2014-01-01

    Peri-stent contrast staining and late acquired malapposition represent pathological vessel wall healing patterns following percutaneous coronary intervention with stent implantation. Earlier studies have described these abnormal vessel wall responses commonly present after implantation of first......-generation drug-eluting stents. These coronary vascular changes can cause flow disturbance and thereby dispose for later thrombotic events. This case report, based on coronary optical frequency domain imaging, describes peri-stent contrast staining, major evaginations and severe malapposition occurring 18months...... after third-generation biolimus-eluting stent implantation....

  16. Late stent malapposition and marked positive vessel remodeling after sirolimus-eluting coronary stent implantation

    Institute of Scientific and Technical Information of China (English)

    ZHANG Feng; QIAN Ju-ying; GE Jun-bo

    2006-01-01

    @@ It has been reported that positive remodeling, regression of neointimal hyperplasia, and late malapposition are associated with brachytherapy, one of the approaches to prevent first-time and recurrent in-stent restenosis.1,2 Recently, some drug-eluting stents have been demonstrated to dramatically reduce restenosis rates.3,4 Despite these promising results, these drug-eluting stents may have the same potential risks as brachytherapy, with some similarities between the 2 technologies in anti- proliferative effects on vascular smooth muscle cells and endothelial cells. We reported a case of late stent malapposition and marked positive vessel remodeling after sirolimus-eluting coronary stent implantation.

  17. Low energy recoil detection with a spherical proportional counter

    CERN Document Server

    Savvidis, I; Eleftheriadis, C; Giomataris, I; Papaevangellou, T

    2016-01-01

    We present low energy recoil detection results in the keV energy region, from measurements performed with the Spherical Proportional Counter (SPC). An ${}^{241}Am-{}^{9}{Be}$ fast neutron source is used in order to obtain neutron-nucleus elastic scattering events inside the gaseous volume of the detector. The detector performance in the $keV$ energy region was resolved by observing the $5.9\\ keV$ line of a ${}^{55}Fe$ X-ray source, with energy resolution of $9\\%$ ($\\sigma$). The toolkit GEANT4 was used to simulate the irradiation of the detector by an ${}^{241}Am-{}^{9}{Be}$ source, while SRIM was used to calculate the Ionization Quenching Factor (IQF). The GEANT4 simulated energy deposition spectrum in addition with the SRIM calculated quenching factor provide valuable insight to the experimental results. The performance of the SPC in low energy recoil detection makes the detector a good candidate for a wide range of applications, including Supernova or reactor neutrino detection and Dark Matter (WIMP) searc...

  18. Oscillation and recoil of single and consecutively printed droplets

    Science.gov (United States)

    Yang, Xin; Chhasatia, Viral; Sun, Ying

    2012-11-01

    Drops are often used as building blocks for line and pattern printing where their interactions play an important role in determining the morphology and properties of deposited functional materials. In this study, the impact, spreading and oscillation of single and consecutively printed drops on substrates of different wettabilities are examined using a high speed camera. The results show that, for a single droplet impacting at a low Weber number, both the inertia and surface tension play important roles in the initial spreading stage before the droplet starts to oscillate. On a substrate of higher wettability, drop oscillation is damped down faster due to stronger viscous dissipation resulted from a longer liquid oscillation path. It is also found that when a drop impacting on an evaporating sessile drop sitting on a hydrophobic substrate, recoil of the combined drop is observed, in contrast to no recoil for the impact of a single drop under the same condition. Furthermore, a single-degree-of-freedom vibration model for the height of oscillating single and combined drops on a hydrophobic substrate is established. The results show that as viscosity of liquid increases, damping of drop oscillation becomes faster, and the combined drop oscillates longer compared to a single drop.

  19. Contribution of recoil atoms to irradiation damage in absorber materials

    Science.gov (United States)

    Simeone, D.; Hablot, O.; Micalet, V.; Bellon, P.; Serruys, Y.

    1997-08-01

    Absorbing materials are used to control the reactivity of nuclear reactors by taking advantage of nuclear reactions (e.g., 10B(n,α) 7Li) where neutrons are absorbed. During such reactions, energetic recoils are produced. As a result, radiation damage in absorbing materials originates both from these nuclear reactions and from elastic collisions between neutrons and atoms. This damage eventually leads to a partial destruction of the materials, and this is the main limitation on their lifetime in nuclear reactors. Using a formalism developed to calculate displacements per atoms (dpa) in a multi atomic target, we have calculated damages in terms of displacements per atom in a (n,α) absorbing material taking into account geometrical effects of 10 boron self shielding and transmutation reactions induced by neutrons inside the absorber. Radiation damage is calculated for boron carbide and hafnium diboride ceramics in a Pressurized Water Reactor environment. It is shown that recoils produced by nuclear reactions account for the main part of the radiation damage created in these ceramics. Damages are calculated as a function of the distance from the center of an absorber pellet. Due to the self-shielding effect, these damage curves exhibit sharp maxima, the position of which changes in time.

  20. Biological coating materials of intravascular stent surface and intravascular restenosis%血管内支架表面生物涂层材料与血管内再狭窄

    Institute of Scientific and Technical Information of China (English)

    徐海峰

    2011-01-01

    -term clinical effects of drug-eluting stent in st ent restenosis.METHODS: An online search of Chinese Journal Full-text Database was performed for articles with the key words of “drug-eluting stent”, “obstruction” and “restenosis”. Meta analysis and repetitive studies were excluded. A total of 25 articles were retained,involving the progress of stent placement, the prevention of stent stenosis and the effects of different stent types, materials on recanalizing rate and recanalizing time.RESULTS AND CONCLUSION: Using drug-loading technology and controlled drug release technology, the drug-eluting stent mechanically support the lesion vessels; in the mean time, drugs that inhibit the proliferation of vascular smooth muscle cells release slowly from the stent surface, act on the vascular walls touching the stent. Thereby, problems of elastic recoil and intima hyperplasia are solved. With the improvement and innovation of interventional equipments for coronary, drug-eluting stent technology is maturing and developing. The design concept of the emerging drug-eluting stent technology is based on drug screening and controlled drug release system. It is believed that drug-eluting stents will be used in a wide range of complex vascular lesions (especially venous diseases and vascular injuries) and other organ diseases.

  1. Iliocaval Confluence Stenting for Chronic Venous Obstructions

    Energy Technology Data Exchange (ETDEWEB)

    Graaf, Rick de, E-mail: r.de.graaf@mumc.nl [Maastricht University Medical Centre (MUMC), Department of Radiology (Netherlands); Wolf, Mark de, E-mail: markthewolf@gmail.com [Maastricht University Medical Centre (MUMC), Department of Surgery (Netherlands); Sailer, Anna M., E-mail: anni.sailer@mumc.nl [Maastricht University Medical Centre (MUMC), Department of Radiology (Netherlands); Laanen, Jorinde van, E-mail: jorinde.van.laanen@mumc.nl; Wittens, Cees, E-mail: c.wittens@me.com [Maastricht University Medical Centre (MUMC), Department of Surgery (Netherlands); Jalaie, Houman, E-mail: hjalaie@ukaachen.de [University Hospital Aachen, Department of Surgery (Germany)

    2015-10-15

    PurposeDifferent techniques have been described for stenting of venous obstructions. We report our experience with two different confluence stenting techniques to treat chronic bi-iliocaval obstructions.Materials and MethodsBetween 11/2009 and 08/2014 we treated 40 patients for chronic total bi-iliocaval obstructions. Pre-operative magnetic resonance venography showed bilateral extensive post-thrombotic scarring in common and external iliac veins as well as obstruction of the inferior vena cava (IVC). Stenting of the IVC was performed with large self-expandable stents down to the level of the iliocaval confluence. To bridge the confluence, either self-expandable stents were placed inside the IVC stent (24 patients, SECS group) or high radial force balloon-expandable stents were placed at the same level (16 patients, BECS group). In both cases, bilateral iliac extensions were performed using nitinol stents.ResultsRecanalization was achieved for all patients. In 15 (38 %) patients, a hybrid procedure with endophlebectomy and arteriovenous fistula creation needed to be performed because of significant involvement of inflow vessels below the inguinal ligament. Mean follow-up was 443 ± 438 days (range 7–1683 days). For all patients, primary, assisted-primary, and secondary patency rate at 36 months were 70, 73, and 78 %, respectively. Twelve-month patency rates in the SECS group were 85, 85, and 95 % for primary, assisted-primary, and secondary patency. In the BECS group, primary patency was 100 % during a mean follow-up period of 134 ± 118 (range 29–337) days.ConclusionStenting of chronic bi-iliocaval obstruction shows relatively high patency rates at medium follow-up. Short-term patency seems to favor confluence stenting with balloon-expandable stents.

  2. Compliance Study of Endovascular Stent Grafts Incorporated with Polyester and Polyurethane Graft Materials in both Stented and Unstented Zones

    Directory of Open Access Journals (Sweden)

    Ying Guan

    2016-08-01

    Full Text Available Compliance mismatch between stent graft and host artery may induce complications and blood flow disorders. However, few studies have been reported on stent graft compliance. This study aims to explore the deformation and compliance of stent graft in stented and unstented zones under three pressure ranges. Compliance of two stent grafts incorporated with polyurethane graft (nitinol-PU and polyester graft (nitinol-PET materials respectively were tested; the stents used in the two stent grafts were identical. For the circumferential deformation of the stent grafts under each pressure range, the nitinol-PET stent graft was uniform in both zones. The nitinol-PU stent graft was circumferentially uniform in the stented zone, however, it was nonuniform in the unstented zone. The compliance of the PU graft material was 15 times higher than that of the PET graft. No significant difference in compliance was observed between stented and unstented zones of the nitinol-PET stent graft regardless of the applied pressure range. However, for the nitinol-PU stent graft, compliance of the unstented PU region was approximately twice that of the stented region; thus, compliance along the length of the nitinol-PU stent graft was not constant and different from that of the nitinol-PET stent graft.

  3. INTRAVASCULAR ULTRASOUND EVALUATING CORONARY STENTS FOR PATIENTS WITH CORONARY ARTERY DISEASE: COMPARED OLD WITH NEW MULTILINK STENTS

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Objective.It was suggested that coronary stent design and coating may affect stent performance and hence induce varying degrees of thrombogenesis and neointimal hyperplasia.The purpose of this study is to compare the 6 month follow up results between old and new Multilink stents with the method of intravascular ultrasound (IVUS) imaging.Methods.We have performed old (n=40) and new (n=35) Multilink stent implantations on 75 patients with coronary artery disease.Coronary angiography was performed before,immediately after,and 6 months after the in stent procedure respectively.Six month follow up IVUS imaging was performed and analyzed off line.Results.Minimal lumen cross sectional area (CSA) of new Multilink stents was significantly larger than that of old Multilink stents (P=0.0053).Mean stent lumen area of new Multilink stents was significantly larger than that of old Multilink stents (P=0.040).Similarly,minimal lumen diameter (MLD) of new Multilink stents was larger than that of old Multilink stents (P= 0.011).Old Multilink stents had a higher percentage of plaque area than new Multilink stents.Conclusion.The new Multilink stent is obviously superior to old Multilink stents,in particular,in the stent MLD and lumen CSA- - major determinants of the restenosis.

  4. Coronary artery stent geometry and in-stent contrast attenuation with 64-slice computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Schepis, Tiziano; Koepfli, Pascal; Gaemperli, Oliver; Eberli, Franz R.; Luescher, Thomas F. [University Hospital Zurich, Cardiovascular Center, Zurich (Switzerland); Leschka, Sebastian; Desbiolles, Lotus; Husmann, Lars; Wildermuth, Simon; Marincek, Borut; Alkadhi, Hatem [University Hospital Zurich, Institute of Diagnostic Radiology, Zurich (Switzerland); Kaufmann, Philipp A. [University Hospital Zurich, Cardiovascular Center, Zurich (Switzerland); Zurich Center for Integrative Human Physiology, Zurich (Switzerland)

    2007-06-15

    We aimed at assessing stent geometry and in-stent contrast attenuation with 64-slice CT in patients with various coronary stents. Twenty-nine patients (mean age 60 {+-} 11 years; 24 men) with 50 stents underwent CT within 2 weeks after stent placement. Mean in-stent luminal diameter and reference vessel diameter proximal and distal to the stent were assessed with CT, and compared to quantitative coronary angiography (QCA). Stent length was also compared to the manufacturer's values. Images were reconstructed using a medium-smooth (B30f) and sharp (B46f) kernel. All 50 stents could be visualized with CT. Mean in-stent luminal diameter was systematically underestimated with CT compared to QCA (1.60 {+-} 0.39 mm versus 2.49 {+-} 0.45 mm; P < 0.0001), resulting in a modest correlation of QCA versus CT (r = 0.49; P < 0.0001). Stent length as given by the manufacturer was 18.2 {+-} 6.2 mm, correlating well with CT (18.5 {+-} 5.7 mm; r = 0.95; P < 0.0001) and QCA (17.4 {+-} 5.6 mm; r = 0.87; P < 0.0001). Proximal and distal reference vessel diameters were similar with CT and QCA (P = 0.06 and P = 0.03). B46f kernel images showed higher image noise (P < 0.05) and lower in-stent CT attenuation values (P < 0.001) than images reconstructed with the B30f kernel. 64-slice CT allows measurement of coronary artery in-stent density, and significantly underestimates the true in-stent diameter compared to QCA. (orig.)

  5. Crush stenting in treating coronary bifurcate lesions: paclitaxel eluting stents versus sirolimus eluting stents

    Institute of Scientific and Technical Information of China (English)

    CHEN Shao-liang; SUN Xue-wen; HU Da-yi; Tak W. Kwan; ZHANG Jun-jie; YE Fei; CHEN Yun-dai; ZHU Zhong-sheng; LIN Song; TIAN Nai-liang; LIU Zhi-zhong; FANG Wei-yi

    2008-01-01

    Background Because no data regarding the comparison of crush stenting with pactitaxel(PES)or sirolimus eluting stents(SES)for coronary bifurcate lesions have been reported,we compared the clinical outcomes of these two types of stents.Methods Two hundred and thirty patients with 242 bifurcate lesions were enrolled in a prospective,nonrandomized trial.Primary endpoints included myocardial infarction,cardiac death and target vessel revascularization at 8 months.Results All patients were followed up clinically and 82%angiographically at 8 months.Final kissing balloon inflation was performed in 72%in the PES and 75%in the SES groups(P>0.05).Compared to the SES group,PES group had a higher late loss and incidence of restenosis(P=0.04)in the prebifurcation vessel segment.The postbifurcation vessel segment in the PES group had a greater late loss((0.7+0.6)mm vs(0.3±0.4)mm,P<0.001)and higher restenosis in the side branch(25.5%vs 15.6%,P=0.04)when compared to the SES group.There was significant difference of insegment restenosis in the entire main vessel between PES and SES groups (P=0.004).Target lesion revascularization was more frequently seen in the PES group as compared to the SES group(P=0.01).There was significant difference in the accumulative MACE between these two groups(P=0.01).The survival rate free from target lesion revascularization was significantly higher in the SES group when compared to the PES group(P<0.001).Conclusion SES is superior to PES in reducing restenosis and target lesion revascularization by 8-month follow-up after crush stenting for bifurcate lesions.

  6. 21 CFR 876.4620 - Ureteral stent.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Ureteral stent. 876.4620 Section 876.4620 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GASTROENTEROLOGY-UROLOGY DEVICES Surgical Devices § 876.4620 Ureteral stent. (a) Identification. A ureteral...

  7. Stent placement for esophageal strictures : an update

    NARCIS (Netherlands)

    Hirdes, Meike Madeleine Catharine; Vleggaar, Frank Paul; Siersema, Peter Derk

    2011-01-01

    The use of stents for esophageal strictures has evolved rapidly over the past 10 years, from rigid plastic tubes to flexible self-expanding metal (SEMS), plastic (SEPS) and biodegradable stents. For the palliative treatment of malignant dysphagia both SEMS and SEPS effectively provide a rapid relief

  8. Optimal control of gun recoil in direct fire using magnetorheological absorbers

    Science.gov (United States)

    Singh, Harinder J.; Wereley, Norman M.

    2014-05-01

    Optimal control of a gun recoil absorber is investigated for minimizing recoil loads and maximizing rate of fire. A multi-objective optimization problem was formulated by considering the mechanical model of the recoil absorber employing a spring and a magnetorheological (MR) damper. The damper forces are predicted by evaluating pressure drops using a nonlinear Bingham-plastic model. The optimization methodology provides multiple optimal design configurations with a trade-off between recoil load minimization and increased rate of fire. The configurations with low or high recoil loads imply low or high rate of fire, respectively. The gun recoil absorber performance is also analyzed for perturbations in the firing forces. The adaptive control of the MR damper for varying gun firing forces provides a smooth operation by returning the recoil mass to its battery position (ready to reload and fire) without incurring an end-stop impact. Furthermore, constant load transmissions are observed with respect to the recoil stroke by implementing optimal control during the simulated firing events.

  9. Drug eluting stents: Current status and new developments

    NARCIS (Netherlands)

    G. Ertaş; H.M.M. van Beusekom (Heleen)

    2012-01-01

    textabstractDespite the favorable impact of drug eluting stents on stent restenosis, their long-term reliability is considered worrisome by some because of stent thrombosis. Often attributed to adverse reactions to the stent platform, both the drugs and polymer characteristics have been further adva

  10. Mesenchymal stem cell seeding promotes reendothelialization of the endovascular stent.

    Science.gov (United States)

    Wu, Xue; Wang, Guixue; Tang, Chaojun; Zhang, Dechuan; Li, Zhenggong; Du, Dingyuan; Zhang, Zhengcai

    2011-09-01

    This study is designed to make a novel cell seeding stent and to evaluate reendothelialization and anti-restenosis after the stent implantation. In comparison with cell seeding stents utilized in previous studies, Mesenchymal stem cells (MSCs) have advantages on promoting of issue repair. Thus it was employed to improve the reendothelialization effects of endovascular stent in present work. MSCs were isolated by density gradient centrifugation and determined as CD29(+) CD44(+) CD34(-) cells by immunofluorescence and immunocytochemistry; gluten and polylysine coated stents were prepared by ultrasonic atomization spray, and MSCs seeded stents were made through rotation culture according to the optimized conditions that were determined in previous studies. The results from animal experiments, in which male New Zealand white rabbits were used, show that the reendothelialization of MSCs coated stents can be completed within one month; in comparison with 316L stainless steel stents (316L SS stents) and gluten and polylysine coated stents, the intimal hyperplasia and in-stent restenosis are significantly inhibited by MSCs coated stents. Endovascular stent seeded with MSCs promotes reendothelialization and inhibits the intimal hyperplasia and in-stent restenosis compared with the 316L SS stents and the gluten and polylysine coated stents.

  11. Commissioning of the recoil silicon detector for the HERMES experiment

    Energy Technology Data Exchange (ETDEWEB)

    Pickert, N.C.

    2008-02-15

    The reconstruction of the missing mass is limited by the position and momentum resolution of the HERMES spectrometer. In order to reach a higher accuracy in the measurements the backscattered nucleon must also be detected. A detector suited for this must give the possibility, to determine the momentum of the particles over a very large range: from minimally ionizing particles up to protons, which are stopped in the detector. The detector must also be able to discriminate hadrons and mesons as well as cover the complete spatial region around the target. In the winter 2005-2006 such a recoil detector was installed in the HERMES experiment. The detector sonsists of three partial detectors, a silicon counter within the scattering chamber, a sintillating-fiber detector and a photon detector. Before the installation of the detector the silicon modules were tested in a bench test and checked together with the other particle detectors in a test experiment. A large part of this dissertation is dedicated to the planning and performance of these tests as well to the evaluation of them. It could be show, that the modules worked accordly to their specifications, however because of unexpectedly high noise a signal correction became necessary. Different models for the correction were developed and tested in the framework of these thesis. In spite of the high noise cosmic muons could be detected and their energy deposition measured with a signal-to-noise ratio of 2:1. In the winter break 2005-2006 the recoil detector was installed into the HERMES experiment. First diagnosis and analysis software was developed. The silicon detector measured successfully energy depositions of minimally ionizing particles up to protons stopped in the sensor. Minimally ionizing particles could be detected with a signal-to-noise ratio of 5:1. By means of track information of the scintillating-fiber detector protons could be discriminated from pions and other mesons by the silicon detector. The HERMES

  12. Atrial septal stenting - How I do it?

    Directory of Open Access Journals (Sweden)

    Kothandam Sivakumar

    2015-01-01

    Full Text Available A wide atrial communication is important to maintain hemodynamics in certain forms of congenital and acquired heart defects. In comparison to balloon septostomy or blade septostomy, atrial septal stenting provides a controlled, predictable, and long-lasting atrial communication. It often needs a prior Brockenbrough needle septal puncture to obtain a stable stent position. A stent deployed across a previously dilated and stretched oval foramen or tunnel form of oval foramen carries higher risk of embolization. This review provides technical tips to achieve a safe atrial septal stenting. Even though this is a "How to do it article," an initial discussion about the indications for atrial septal stenting is vital as the resultant size of the atrial septal communication should be tailored for each indication.

  13. Foreign body contamination during stent implantation.

    Science.gov (United States)

    Whelan, D M; van Beusekom, H M; van der Giessen, W J

    1997-03-01

    The treatment of coronary artery disease using stents has become a widely accepted technique. However, the inadvertent co-implantation of contaminating factors with the stent has received little attention. We studied histological cross-sections of stented porcine coronary arteries and observed contamination of some vessels with surgical glove powder and textile fibres. The contaminating particles were associated with a foreign body reaction. Such a reaction could delay the wound-healing response of a stented vessel and thereby prolong the period in which subacute thrombosis could occur. It is also proposed that air contamination could affect the thrombogenicity of the stent. Appropriate measures should be followed to reduce the chance of contamination occurring.

  14. First measurement of surface nuclear recoil background for argon dark matter searches

    CERN Document Server

    Xu, Jingke; Westerdale, Shawn; Calaprice, Frank; Wright, Alexander; Shi, Zhiming

    2016-01-01

    One major background in direct searches for weakly interacting massive particles (WIMPs) comes from the deposition of radon progeny on detector surfaces. The most dangerous surface background is the $^{206}$Pb recoils produced by $^{210}$Po decays. In this letter, we report the first characterization of this background in liquid argon. The scintillation signal of low energy Pb recoils is measured to be highly quenched in argon, and we estimate that the 103keV $^{206}$Pb recoil background will produce a signal equal to that of a ~5keV (30keV) electron recoil ($^{40}$Ar recoil). In addition, we demonstrate that this dangerous $^{210}$Po surface background can be suppressed by a factor of ~100 or higher using pulse shape discrimination methods, which can make argon dark matter detectors near background-free and enhance their potential for discovery of medium- and high-mass WIMPs. We also discuss the impact on other low background experiments.

  15. Deconvoluting nonaxial recoil in Coulomb explosion measurements of molecular axis alignment

    Science.gov (United States)

    Christensen, Lauge; Christiansen, Lars; Shepperson, Benjamin; Stapelfeldt, Henrik

    2016-08-01

    We report a quantitative study of the effect of nonaxial recoil during Coulomb explosion of laser-aligned molecules and introduce a method to remove the blurring caused by nonaxial recoil in the fragment-ion angular distributions. Simulations show that nonaxial recoil affects correlations between the emission directions of fragment ions differently from the effect caused by imperfect molecular alignment. The method, based on analysis of the correlation between the emission directions of the fragment ions from Coulomb explosion, is used to deconvolute the effect of nonaxial recoil from experimental fragment angular distributions. The deconvolution method is then applied to a number of experimental data sets to correct the degree of alignment for nonaxial recoil, to select optimal Coulomb explosion channels for probing molecular alignment, and to estimate the highest degree of alignment that can be observed from selected Coulomb explosion channels.

  16. Recoiling black holes: prospects for detection and implications of spin alignment

    CERN Document Server

    Blecha, Laura; Kelley, Luke Zoltan; Torrey, Paul; Vogelsberger, Mark; Nelson, Dylan; Springel, Volker; Snyder, Gregory; Hernquist, Lars

    2015-01-01

    Supermassive black hole (BH) mergers produce powerful gravitational wave (GW) emission. Asymmetry in this emission imparts a recoil kick to the merged BH, which can eject the BH from its host galaxy altogether. Recoiling BHs could be observed as offset active galactic nuclei (AGN). Several candidates have been identified, but systematic searches have been hampered by large uncertainties regarding their observability. By extracting merging BHs and host galaxy properties from the Illustris cosmological simulations, we have developed a comprehensive model for recoiling AGN. Here, for the first time, we model the effects of BH spin alignment and recoil dynamics based on the gas-richness of host galaxies. For comparable assumptions, we find much higher rates of recoiling AGN than Volonteri & Madau (2008), indicating systematic differences between BH populations in semi-analytic models and cosmological simulations. We predict that if BH spins are not highly aligned, seeing-limited observations could resolve off...

  17. Carbon cluster diagnostics-I: Direct Recoil Spectroscopy (DRS) of Ar+ and Kr+ bombarded graphite

    CERN Document Server

    Ahmad, Shoaib; Qayyum, A; Ahmad, B; Bahar, K; Arshed, W

    2016-01-01

    Measurements of the energy spectra of multiply charged positive and negative carbon ions recoiling from graphite surface under 100 and 150 keV argon and krypton ion bombardment are presented. With the energy spectrometer set at recoil angle of 79.5 degrees, direct recoil (DR) peaks have been observed with singly as well as multiply charged carbon ions , where n = 1 to 6. These monatomic and cluster ions have been observed recoiling with the characteristic recoil energy E(DR) . We have observed sharp DR peaks. A collimated projectile beam with small divergence is supplemented with a similar collimation before the energy analyzer to reduce the background of sputtered ions due to scattered projectiles.

  18. Electron recombination in low-energy nuclear recoils tracks in liquid argon

    CERN Document Server

    Wojcik, Mariusz

    2015-01-01

    This paper presents an analysis of electron-ion recombination processes in ionization tracks of recoiled atoms in liquid argon (LAr) detectors. The analysis is based on the results of computer simulations which use realistic models of electron transport and reactions. The calculations reproduce the recent experimental results of the ionization yield from 6.7 keV nuclear recoils in LAr. The statistical distribution of the number of electrons that escape recombination is found to deviate from the binomial distribution, and estimates of recombination fluctuations for nuclear recoils tracks are obtained. A study of the recombination kinetics shows that a significant part of electrons undergo very fast static recombination, an effect that may be responsible for the weak drift-field dependence of the ionization yield from nuclear recoils in some noble liquids. The obtained results can be useful in the search for hypothetical dark matter particles and in other studies that involve detection of recoiled nuclei.

  19. Call for standards in technical documentation of intracoronary stents.

    Science.gov (United States)

    Lanzer, Peter; Gijsen, Frank J H; Topoleski, L D Timmie; Holzapfel, Gerhard A

    2010-01-01

    At present, the product information of intracoronary stents provided by the industry contains only limited technical data restricting judgments on the in vivo performance of individual products. Available experimental and clinical evidence suggests that interventional target sites display highly heterogeneous biomechanical behavior needed to be matched by specific stent and stent delivery system characteristics. To allow individualized stent-lesion matching, both, understanding of biomechanical properties of the atherosclerotic coronary artery lesions and expert knowledge of the intracoronary stent systems, are required. Here, the authors review some of the initial data on mechanical properties of coronary artery lesions potentially relevant to stenting and suggest standards for technical documentation of intracoronary stents.

  20. Should antiplatelet therapy be interrupted in drug eluting stent recipients throughout the periendoscopic period? A very late stent thrombosis case re-port and review of the literature

    Institute of Scientific and Technical Information of China (English)

    Peng DONG; Xin-Chun YANG; Su-Yan BIAN

    2014-01-01

    In-stent thrombosis after cessation of antiplatelet medications in patients with drug-eluting stents (DES) is a significant problem in medical practice, particularly in the perioperative period. We report a case of an 87-year-old man with a medical history of hypertension, coronary artery disease and chronic atrophic gastritis. Very late thrombosis of a sirolimus-eluting stent occurred 1207 days after implantation, seven months after discontinuation of clopidogrel, and the interruption of aspirin 13 days in preparation of an elective endoscopic gastroin-testinal procedure presented with acute myocardial infarction. The patient was treated with thrombectomy and successfully revascularized with superimposition of two sirolimus-eluting stents. Medications administered in the catheterization laboratory included low molecular weight heparin and nitroglycerin. Flow was defined as grade 2 according to the thrombolysis in myocardial infarction scale. Electrocardio-gram after the procedure revealed persistent, but decreased, ST-segment elevation in the anterolateral leads. The patient recovered and was discharged on aspirin and clopidogrel indefinitely. There was no cardiac event during the two year follow-up period. This case underlines the importance of maintaining the balance of thrombosis and bleeding during perioperation of non-cardiac procedure and the possible need for continuation of aspirin therapy during periendoscopic procedures among patients with low bleeding risks who received DES.

  1. Triple antithrombotic therapy in patients with atrial fibrillation undergoing coronary artery stenting: hovering among bleeding risk, thromboembolic events, and stent thrombosis

    Directory of Open Access Journals (Sweden)

    Menozzi Mila

    2012-10-01

    Full Text Available Abstract Dual antiplatelet treatment with aspirin and clopidogrel is the antithrombotic treatment recommended after an acute coronary syndrome and/or coronary artery stenting. The evidence for optimal antiplatelet therapy for patients, in whom long-term treatment oral anticoagulation is mandatory, is however scarce. To evaluate the safety and efficacy of the various antithrombotic strategies adopted in this population, we reviewed the available evidence on the management of patients receiving oral anticoagulation, such as a vitamin-k-antagonists, referred for coronary artery stenting. Atrial fibrillation is the most frequent indication for oral anticoagulation. The need of starting antiplatelet therapy in this clinical scenario raises concerns about the combination to choose: triple therapy with warfarin, aspirin, and a thienopyridine being the most frequent and advised. The safety of this regimen appeared suboptimal because of an increased risk in hemorrhagic complications. On the other hand, the combination of oral anticoagulation and an antiplatelet agent is suboptimal in preventing thromboembolic events and stent thrombosis; dual antiplatelet therapy may be considered only when a high hemorrhagic risk and low thromboembolic risk are perceived. Indeed, the need for prolonged multiple-drug antithrombotic therapy increases the bleeding risks when drug eluting stents are used. Since current evidence derives mainly from small, single-center and retrospective studies, large-scale prospective multicenter studies are urgently needed.

  2. Biliary stenting: indications, choice of stents and results: European Society of Gastrointestinal Endoscopy (ESGE) clinical guideline.

    Science.gov (United States)

    Dumonceau, J-M; Tringali, A; Blero, D; Devière, J; Laugiers, R; Heresbach, D; Costamagna, G

    2012-03-01

    This article is part of a combined publication that expresses the current view of the European Society of Gastrointestinal Endoscopy about endoscopic biliary stenting. The present Clinical Guideline describes short-term and long-term results of biliary stenting depending on indications and stent models; it makes recommendations on when, how, and with which stent to perform biliary drainage in most common clinical settings, including in patients with a potentially resectable malignant biliary obstruction and in those who require palliative drainage of common bile duct or hilar strictures. Treatment of benign conditions (strictures related to chronic pancreatitis, liver transplantation, or cholecystectomy, and leaks and failed biliary stone extraction) and management of complications (including stent revision) are also discussed. A two-page executive summary of evidence statements and recommendations is provided. A separate Technology Review describes the models of biliary stents available and the stenting techniques, including advanced techniques such as insertion of multiple plastic stents, drainage of hilar strictures, retrieval of migrated stents and combined stenting in malignant biliary and duodenal obstructions.The target readership for the Clinical Guideline mostly includes digestive endoscopists, gastroenterologists, oncologists, radiologists, internists, and surgeons while the Technology Review should be most useful to endoscopists who perform biliary drainage.

  3. Updates on the use of ureteral stents: focus on the Resonance® stent

    Directory of Open Access Journals (Sweden)

    Thomas MT Turk

    2010-12-01

    Full Text Available Manoj V Rao, Anthony J Polcari, Thomas MT TurkDepartment of Urology, Loyola University Medical Center, Maywood, IL, USAAbstract: The Resonance® metallic ureteral stent is one of the latest additions to the urologist’s armamentarium in managing ureteral obstruction. One advantage of this stent over traditional polymer-based stents is resistance to encrustation with stone material, which allows longer dwell times and less frequent exchange procedures. Although exchanging a metallic stent is slightly more complicated than exchanging a polymer stent, the fluoroscopic techniques required are familiar to most urologists. The Resonance stent is also more resistant to compression by external forces, potentially allowing greater applicability in patients with metastatic cancer. Furthermore, the use of this stent in patients with benign ureteral obstruction is shown to be associated with significant cost reduction. Clinical studies on the use of this stent are accumulating and the results are mixed, although Level 1 evidence is lacking. In this article we present a comprehensive review of the available literature on the Resonance metallic ureteral stent.Keywords: resonance, metallic, ureteral, stent, obstruction

  4. Hybrid stent device of flow-diverting effect and stent-assisted coil embolization formed by fractal structure.

    Science.gov (United States)

    Kojima, Masahiro; Irie, Keiko; Masunaga, Kouhei; Sakai, Yasuhiko; Nakajima, Masahiro; Takeuchi, Masaru; Fukuda, Toshio; Arai, Fumihito; Negoro, Makoto

    2016-05-01

    This paper presents a novel hybrid medical stent device. This hybrid stent device formed by fractal mesh structures provides a flow-diverting effect and stent-assisted coil embolization. Flow-diverter stents decrease blood flow into an aneurysm to prevent its rupture. In general, the mesh size of a flow-diverter stent needs to be small enough to prevent blood flow into the aneurysm. Conventional flow-diverter stents are not available for stent-assisted coil embolization, which is an effective method for aneurysm occlusion, because the mesh size is too small to insert a micro-catheter for coil embolization. The proposed hybrid stent device is capable of stent-assisted coil embolization while simultaneously providing a flow-diverting effect. The fractal stent device is composed of mesh structures with fine and rough mesh areas. The rough mesh area can be used to insert a micro-catheter for stent-assisted coil embolization. Flow-diverting effects of two fractal stent designs were composed to three commercially available stent designs. Flow-diverting effects were analyzed using computational fluid dynamics (CFD) analysis and particle image velocimetry (PIV) experiment. Based on the CFD and PIV results, the fractal stent devices reduce the flow velocity inside an aneurism just as much as the commercially available flow-diverting stents while allowing stent-assisted coil embolization.

  5. Transient coronary aneurysm formation after Nevo™ stent implantation versus persistent coronary aneurysm after Cypher Select™ stent implantation

    DEFF Research Database (Denmark)

    Christiansen, Evald Høj; Lassen, Jens Flensted; Jensen, Lisette Okkels

    2011-01-01

    We implanted a Cypher Select™ coronary stent and two months later a Nevo™ sirolimus-eluting coronary stent in another vessel. At a prescheduled angiographic follow-up, coronary aneurysms were seen in the two stented segments, 6 and 8 months after stent implantation, respectively. Six months later...

  6. On the Superposition and Elastic Recoil of Electromagnetic Waves

    CERN Document Server

    Schantz, Hans G

    2014-01-01

    Superposition demands that a linear combination of solutions to an electromagnetic problem also be a solution. This paper analyzes some very simple problems: the constructive and destructive interferences of short impulse voltage and current waves along an ideal free-space transmission line. When voltage waves constructively interfere, the superposition has twice the electrical energy of the individual waveforms because current goes to zero, converting magnetic to electrical energy. When voltage waves destructively interfere, the superposition has no electrical energy because it transforms to magnetic energy. Although the impedance of the individual waves is that of free space, a superposition of waves may exhibit arbitrary impedance. Further, interferences of identical waveforms allow no energy transfer between opposite ends of a transmission line. The waves appear to recoil elastically one from another. Although alternate interpretations are possible, these appear less likely. Similar phenomenology arises i...

  7. Dielectric barrier structure with hollow electrodes and its recoil effect

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Shuang; Chen, Qunzhi; Liu, Jiahui; Wang, Kaile [Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871 (China); Jiang, Zhe; Sun, Zhili [College of Engineering, Peking University, Beijing 100871 (China); Zhang, Jue; Fang, Jing [Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871 (China); College of Engineering, Peking University, Beijing 100871 (China)

    2015-06-15

    A dielectric barrier structure with hollow electrodes (HEDBS), in which gas flow oriented parallel to the electric field, was proposed. Results showed that with this structure, air can be effectively ignited, forming atmospheric low temperature plasma, and the proposed HEDBS could achieve much higher electron density (5 × 10{sup 15}/cm{sup 3}). It was also found that the flow condition, including outlet diameter and flow rate, played a key role in the evolution of electron density. Optical emission spectroscopy diagnostic results showed that the concentration of reactive species had the same variation trend as the electron density. The simulated distribution of discharge gas flow indicated that the HEDBS had a strong recoil effect on discharge gas, and could efficiently promote generating electron density as well as reactive species.

  8. Elastic recoil detection analysis on the ANSTO heavy ion microprobe

    Science.gov (United States)

    Siegele, R.; Orlic, I.; Cohen, David D.

    2002-05-01

    The heavy ion microprobe at the Australian Nuclear Science and Technology Organisation is capable of focussing heavy ions with an ME/ q2 of up to 100 amu MeV. This makes the microprobe ideally suited for heavy ion elastic recoil detection analysis (ERDA). However, beam currents on a microprobe are usually very small, which requires a detection system with a large solid angle. We apply microbeam heavy ion ERDA using a large solid angle ΔE- E telescope with a gas ΔE detector to layered structures. We demonstrate the capability to measure oxygen and carbon with a lateral resolution of 20 μm, together with determination of the depth of the contamination in thin deposited layers.

  9. Study of nuclear recoils in liquid argon with monoenergetic neutrons

    CERN Document Server

    Regenfus, C; Amsler, C; Creus, W; Ferella, A; Rochet, J; Walter, M

    2012-01-01

    For the development of liquid argon dark matter detectors we assembled a setup in the laboratory to scatter neutrons on a small liquid argon target. The neutrons are produced mono-energetically (E_kin=2.45 MeV) by nuclear fusion in a deuterium plasma and are collimated onto a 3" liquid argon cell operating in single-phase mode (zero electric field). Organic liquid scintillators are used to tag scattered neutrons and to provide a time-of-flight measurement. The setup is designed to study light pulse shapes and scintillation yields from nuclear and electronic recoils as well as from {\\alpha}-particles at working points relevant to dark matter searches. Liquid argon offers the possibility to scrutinise scintillation yields in noble liquids with respect to the populations of the two fundamental excimer states. Here we present experimental methods and first results from recent data towards such studies.

  10. The ANTARES recoil time-of-flight spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Martin, J.W.; Russell, G.J. [New South Wales Univ., Kensington, NSW (Australia); Cohen, D.D.; Dytlewski, N. [Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW (Australia)

    1996-12-31

    The Australian National Tandem for Applied Research (ANTARES), is a 8MV FN tandem particle accelerator at the Australian Nuclear Science and Technology Organisation. Research on the accelerator is divided between two groups, Accelerator Mass Spectrometry (AMS) and lon Beam Analysis (IBA). The IBA group carries out a range of research projects from nuclear physics to materials characterisation. The major IBA project on the accelerator is a recoil time-of-flight spectrometer which consists of two electrostatic time pulse generators and an ion-implanted surface barrier detector. The spectrometer is ideally suited to the profiling of layered multi-element materials, and has been used to characterise materials such as metal-germanides, optoelectronics, superconductors and catalytic converters. This paper will describe the time-of-flight system as well as some recent materials characterisation results. 1 refs., 3 figs.

  11. A Study of Nuclear Recoils in Liquid Argon Time Projection Chamber for the Direct Detection of WIMP Dark Matter

    Energy Technology Data Exchange (ETDEWEB)

    Cao, Huajie [Princeton Univ., NJ (United States)

    2014-11-01

    Robust results of WIMP direct detection experiments depend on rm understandings of nuclear recoils in the detector media. This thesis documents the most comprehensive study to date on nuclear recoils in liquid argon - a strong candidate for the next generation multi-ton scale WIMP detectors. This study investigates both the energy partition from nuclear recoil energy to secondary modes (scintillation and ionization) and the pulse shape characteristics of scintillation from nuclear recoils.

  12. Local sustained delivery of acetylsalicylic acid via hybrid stent with biodegradable nanofibers reduces adhesion of blood cells and promotes reendothelialization of the denuded artery.

    Science.gov (United States)

    Lee, Cheng-Hung; Lin, Yu-Huang; Chang, Shang-Hung; Tai, Chun-Der; Liu, Shih-Jung; Chu, Yen; Wang, Chao-Jan; Hsu, Ming-Yi; Chang, Hung; Chang, Gwo-Jyh; Hung, Kuo-Chun; Hsieh, Ming-Jer; Lin, Fen-Chiung; Hsieh, I-Chang; Wen, Ming-Shien; Huang, Yenlin

    2014-01-01

    Incomplete endothelialization, blood cell adhesion to vascular stents, and inflammation of arteries can result in acute stent thromboses. The systemic administration of acetylsalicylic acid decreases endothelial dysfunction, potentially reducing thrombus, enhancing vasodilatation, and inhibiting the progression of atherosclerosis; but, this is weakened by upper gastrointestinal bleeding. This study proposes a hybrid stent with biodegradable nanofibers, for the local, sustained delivery of acetylsalicylic acid to injured artery walls. Biodegradable nanofibers are prepared by first dissolving poly(D,L)-lactide-co-glycolide and acetylsalicylic acid in 1,1,1,3,3,3-hexafluoro-2-propanol. The solution is then electrospun into nanofibrous tubes, which are then mounted onto commercially available bare-metal stents. In vitro release rates of pharmaceuticals from nanofibers are characterized using an elution method, and a highperformance liquid chromatography assay. The experimental results suggest that biodegradable nanofibers release high concentrations of acetylsalicylic acid for three weeks. The in vivo efficacy of local delivery of acetylsalicylic acid in reducing platelet and monocyte adhesion, and the minimum tissue inflammatory reaction caused by the hybrid stents in treating denuded rabbit arteries, are documented. The proposed hybrid stent, with biodegradable acetylsalicylic acid-loaded nanofibers, substantially contributed to local, sustained delivery of drugs to promote re-endothelialization and reduce thrombogenicity in the injured artery. The stents may have potential applications in the local delivery of cardiovascular drugs. Furthermore, the use of hybrid stents with acetylsalicylic acid-loaded nanofibers that have high drug loadings may provide insight into the treatment of patients with high risk of acute stent thromboses.

  13. MR safety and imaging of neuroform stents at 3T.

    Science.gov (United States)

    Nehra, Arvind; Moran, Christopher J; Cross, Dewitte T; Derdeyn, Colin P

    2004-10-01

    The Neuroform stent is a self-expanding nitinol stent designed for use in wide-necked intracranial aneurysms. Heating and imaging artifacts were evaluated by using a porcine carotid artery aneurysm model in a 3T MR system. A suspended Neuroform stent was tested for deflection. No heating was measured, and no evidence of deflection of the stent was found. Imaging artifacts were minimal. MR imaging in patients with Neuroform stent-treated aneurysms is safe and feasible.

  14. Modified culotte stenting for treatment of complex coronary bifurcation lesions: immediate and 9-month outcomes in a pilot study

    Institute of Scientific and Technical Information of China (English)

    CHEN Liang-long; FAN Lin; CHEN Zhao-yang; ZHEN Xing-chun; LUO Yu-kun; LIN Chao-gui; PENG Ya-fei

    2011-01-01

    Background The optimal stenting strategy for the treatment of coronary bifurcation lesions (CBLs) remains uncertain. The present study observed technical feasibility and reliability, 9-month clinical and angiographic outcomes of the modified culotte stenting (MCS) in the treatment of CBLs with drug-eluting stents.Methods A total of 34 consecutive patients with CBLs that required stenting the parent vessel (PV), the main branch (MB) and the side branch (SB) were included. All patients were first assigned to receive MCS for CBL interventions (per MCS), and might be switched to receive the double-kissing-crush stenting (DKS) in case of temporally acute branch occlusion (per protocol).Results The immediate angiographic or procedural success was achieved in 33/34 (97%) lesions (patients) per MCS, 34/34 (100%) lesions (patients) per protocol with 100% successful final balloon kissing. The long-term clinical success at 9 months was 94% per MCS and 94% per protocol, only 2 patients had reoccurrence of angina but none of them needed target lesion revascularization. There were no procedure-related biomarker elevation, no in-stent thrombosis peri-procedurally and at 9-month follow-up. Quantitative coronary angiography data at 9 months showed that in-stent (6%) or in-segment (6%) binary stenosis was infrequent, and minimal lumen diameter was significantly reduced but late lumen loss was acceptable with only (0.10±0.14) mm for PV, (0.21 ±0.23) mm for MB and (0.27±0.32) mm for SB.Conclusions MCS for treatment of CBLs that required dual-stent implantation was technically easier and safer, readily to complete final balloon kissing, and was associated with high immediate success and optimal 9-month outcomes.

  15. Diagnostic accuracy of 64-slice multidetector CT for detection of in-stent restenosis in an unselected, consecutive patient population

    Energy Technology Data Exchange (ETDEWEB)

    Haraldsdottir, Sigurdis, E-mail: sigurdisha@gmail.com [Boston Medical Center, 72 East Concord Street (Evans 124), Boston, MA, 02118 (United States); Gudnason, Thorarinn, E-mail: thorgudn@landspitali.is [Landspitali University Hospital, Hringbraut, 101 Reykjavik (Iceland); Sigurdsson, Axel F., E-mail: axelfsig@landspitali.is [Landspitali University Hospital, Hringbraut, 101 Reykjavik (Iceland); Gudjonsdottir, Jonina, E-mail: jonina@rd.is [Rontgen Domus Medica, Egilsgata 3, 101 Reykjavik (Iceland); Lehman, Sam J., E-mail: slehman@partners.org [Massachusetts General Hospital, 165 Cambridge Street, Suite 400, Boston, MA 02114 (United States); Eyjolfsson, Kristjan, E-mail: kristey@landspitali.is [Landspitali University Hospital, Hringbraut, 101 Reykjavik (Iceland); Scheving, Sigurpall S., E-mail: sigurpal@landspitali.is [Landspitali University Hospital, Hringbraut, 101 Reykjavik (Iceland); Gibson, C. Michael, E-mail: mgibson@perfuse.org [Beth Israel Deaconess Medical Center, 330 Brookline Avenue, Boston, MA 02115 (United States); Hoffmann, Udo, E-mail: uhoffmann@partners.org [Massachusetts General Hospital, 165 Cambridge Street, Suite 400, Boston, MA 02114 (United States); Jonsdottir, Birna, E-mail: birna@rd.is [Rontgen Domus Medica, Egilsgata 3, 101 Reykjavik (Iceland); Andersen, Karl, E-mail: andersen@landspitali.is [Landspitali University Hospital, Hringbraut, 101 Reykjavik (Iceland)

    2010-11-15

    Objectives: To investigate the diagnostic accuracy of 64-slice multidetector computed tomography (64-CT) for detection of in-stent restenosis (ISR) in an unselected, consecutive patient population. Background: Detection of in-stent restenosis by cardiac CT would be a major advance for the evaluation of patients suspected of having ISR. However, the diagnostic accuracy of current generation 64-CT in this context is not fully established. Methods: We conducted a prospective study on patients with stable angina or acute coronary syndrome with no prior history of coronary artery disease. Six months after percutaneous coronary intervention (PCI) with stent placement they underwent a 64-CT scan (Toshiba Multi-Slice Aquilion 64) and consequently a repeat coronary angiography for comparison. Cardiac CT data sets were analyzed for the presence of in-stent restenosis by two independent expert readers blinded to the coronary angiographic data. Results: Ninety-three patients with a total of 140 stents were evaluated. Males comprised 82% of the study group and the mean age was 63 {+-} 10 years. The mean time from PCI to the repeat coronary angiography was 208 {+-} 37 days and the mean time from 64-CT to repeat coronary angiography was 3.7 {+-} 4.9 days. The restenosis rate according to coronary angiography was 26%. Stent diameter, strut thickness, heart rate and body mass index (BMI) significantly affected image quality. The sensitivity, specificity, positive and negative predictive values of 64-CT for detection of in-stent restenosis were 27%, 95%, 67% and 78%, respectively. Conclusions: Current generation, 64-slice CT, remains limited in its ability to accurately detect in-stent restenosis.

  16. The late acute thrombosis in coronary drug-eluting stent-cases pooled analysis%冠状动脉药物洗脱支架晚发支架内急性血栓形成分析

    Institute of Scientific and Technical Information of China (English)

    王禹; 盖鲁粤; Sueselbeck T; Remppis A; 杨庭树; 陈练; 刘宏斌; 金琴花; 李丽

    2006-01-01

    目的分析近期临床应用冠脉药物洗脱支架(drug-eluting stent,DES)术后,晚发的支架内急性血栓形成病例的发生特点及可能影响因素.方法应用关键词:coronary artery、sirolimus、paclitaxil、drug-elutistent、thrombosis,anuervsm、malapposition等,应用美国国立医学图书馆的PubMed系统和德国海德堡大学的电子期刊系统对临床医学核心期刊进行系统检索.对检索出的12个病例及本中心3例冠状动脉内置入DES后晚发支架内急性血栓形成病例汇总分析.结果共有15例患者,在DES(sirolimus和paclitaxel支架)术后出现晚发的支架内急性血栓形成和(或)同时合并冠脉瘤样扩张、支架与血管壁贴合不良(malapposition).急性血栓发生时间:120~540天.9例患者在停用阿司匹林、氯吡格雷后4~15天发生;3例患者在DES置入部位出现明显冠脉瘤样扩张和(或)瘤腔内血栓形成;4例患者在DES发生急性血栓时、同时置入的6枚普通金属支架完全通畅.结论晚发的DES内急性血栓形成(≥6个月)、支架与血管壁贴合不良、明显的冠脉管壁瘤样扩张造成再次严重的心肌缺血或梗死.

  17. The Supralimus sirolimus-eluting stent.

    Science.gov (United States)

    Lemos, Pedro A; Bienert, Igor

    2013-05-01

    The use of biodegradable polymeric coatings has emerged as a potential bioengineering target to improve the vascular compatibility of coronary drug-eluting stents (DESs). This review summarizes the main features and scientific facts about the Supralimus sirolimus-eluting stent (Sahajanand Medical Technologies Ltd, Surat, India), which is a biodegradable polymer-based, sirolimus-eluting metallic stent that was recently introduced for routine use in Europe. The novel stent is built on a stainless steel platform, coated with a blend of biodegradable polymers (poly-l-lactide, poly-dl-lactide-co-glycolide and polyvinyl pyrrolidone; coating thickness is 4-5 µm). The active agent is the antiproliferative sirolimus in a dose load of 1.4 µg/mm(2), which is released within 48 days. The Supralimus stent was initially evaluated in the single-arm SERIES-I study, which showed binary angiographic restenosis rates of 0% (in-stent) and 1.7% (in-segment) and an in-stent late lumen loss of 0.09 ± 0.28 mm. The multicenter randomized PAINT trial compared two DESs with identical metallic platforms and biodegradable polymer carriers, but different agents (Infinnium [Sahajanand Medical Technologies Pvt Ltd] paclitaxel-eluting stent or Supralimus sirolimus-eluting stent) against bare stents. After 3 years, the pooled DES population had similar rates of cardiac death or myocardial infarction (9 vs 7.1%; p = 0.6), but a lower risk of repeat interventions (10 vs 29.9%; p < 0.01) than controls with bare stents. The incidence of definite or probable stent thrombosis in the pooled DES group was 2.3% (1st year: 1.8%; 2nd year: 0.4% and 3rd year: 0%). These results demonstrate that the novel Supralimus stents are effective in reducing reintervention, while potentially improving the safety profile by decreasing the risk of late-term thrombosis, even though further studies would be necessary to confirm these findings.

  18. The influence of vascular anatomy on carotid artery stenting: a parametric study for damage assessment.

    Science.gov (United States)

    Iannaccone, F; Debusschere, N; De Bock, S; De Beule, M; Van Loo, D; Vermassen, F; Segers, P; Verhegghe, B

    2014-03-01

    Carotid artery stenting is emerging as an alternative technique to surgery for the treatment of symptomatic severe carotid stenosis. Clinical and experimental evidence demonstrates that both plaque morphology and biomechanical changes due to the device implantation can be possible causes of an unsuccessful treatment. In order to gain further insights of the endovascular intervention, a virtual environment based on structural finite element simulations was built to emulate the stenting procedure on generalized atherosclerotic carotid geometries which included a damage model to quantify the injury of the vessel. Five possible lesion scenarios were simulated by changing both material properties and vascular geometrical features to cover both presumed vulnerable and stable plaques. The results were analyzed with respect to lumen gain and wall stresses which are potentially related to the failure of the procedure according to previous studies. Our findings show that an elliptic lumen shape and a thinner fibrous cap with an underlying lipid pool result in higher stenosis reduction, while large calcifications and fibrotic tissue are more prone to recoil. The shielding effect of a thicker fibrous cap helps to reduce local compressive stresses in the soft plaque. The presence of a soft plaque reduces the damage in the healthy vascular structures. Contrarily, the presence of hard plaque promotes less damage volume in the fibrous cap and reduces stress peaks in this region, but they seem to increase stresses in the media-intima layer. Finally the reliability of the achieved results was put into clinical perspective.

  19. Stent graft implantation in an aortic pseudoaneurysm associated with a fractured Cheatham-Platinum stent in aortic coarctation.

    Science.gov (United States)

    Kuhelj, Dimitrij; Berden, Pavel; Podnar, Tomaž

    2016-03-01

    We report a case of aortic pseudoaneurysm associated with a fractured bare Cheatham-Platinum stent following stenting for aortic coarctation. These complications were recognised 6 years after the implantation procedure and were successfully managed by percutaneous stent graft implantation. Staged approach for stent dilatation might prevent development of aortic pseudoaneurysms. In addition, careful follow-up is warranted after stenting for aortic coarctation, particularly in patients with recognised aortic wall injury.

  20. Long-term Results of Endovascular Stent Graft Placement of Ureteroarterial Fistula

    Energy Technology Data Exchange (ETDEWEB)

    Okada, Takuya, E-mail: okabone@gmail.com; Yamaguchi, Masato, E-mail: masato03310402@yahoo.co.jp [Kobe University Hospital, Department of Radiology (Japan); Muradi, Akhmadu, E-mail: muradiakhmadu@gmail.com; Nomura, Yoshikatsu, E-mail: y_katsu1027@yahoo.co.jp [Kobe University Hospital, Center for Endovascular Therapy (Japan); Uotani, Kensuke, E-mail: uotani@tenriyorozu.jp [Tenri Hospital, Department of Radiology (Japan); Idoguchi, Koji, E-mail: idoguchi@ares.eonet.ne.jp [Kobe University Hospital, Center for Endovascular Therapy (Japan); Miyamoto, Naokazu, E-mail: naoka_zu@yahoo.co.jp; Kawasaki, Ryota, E-mail: kawaryo1999@yahoo.co.jp [Hyogo Brain and Heart Center at Himeji, Department of Radiology (Japan); Taniguchi, Takanori, E-mail: tan9523929@yahoo.co.jp [Tenri Hospital, Department of Radiology (Japan); Okita, Yutaka, E-mail: yokita@med.kobe-u.ac.jp [Kobe University Hospital, Department of Cardiovascular Surgery (Japan); Sugimoto, Koji, E-mail: kojirad@med.kobe-u.ac.jp [Kobe University Hospital, Department of Radiology (Japan)

    2013-08-01

    PurposeTo evaluate the safety, efficacy, and long-term results of endovascular stent graft placement for ureteroarterial fistula (UAF).MethodsWe retrospectively analyzed stent graft placement for UAF performed at our institution from 2004 to 2012. Fistula location was assessed by contrast-enhanced computed tomography (CT) and angiography, and freedom from hematuria recurrence and mortality rates were estimated.ResultsStent graft placement for 11 UAFs was performed (4 men, mean age 72.8 {+-} 11.6 years). Some risk factors were present, including long-term ureteral stenting in 10 (91 %), pelvic surgery in 8 (73 %), and pelvic radiation in 5 (45 %). Contrast-enhanced CT and/or angiography revealed fistula or encasement of the artery in 6 cases (55 %). In the remaining 5 (45 %), angiography revealed no abnormality, and the suspected fistula site was at the crossing area between urinary tract and artery. All procedures were successful. However, one patient died of urosepsis 37 days after the procedure. At a mean follow-up of 548 (range 35-1,386) days, 4 patients (36 %) had recurrent hematuria, and two of them underwent additional treatment with secondary stent graft placement and surgical reconstruction. The hematuria recurrence-free rates at 1 and 2 years were 76.2 and 40.6 %, respectively. The freedom from UAF-related and overall mortality rates at 2 years were 85.7 and 54.9 %, respectively.ConclusionEndovascular stent graft placement for UAF is a safe and effective method to manage acute events. However, the hematuria recurrence rate remains high. A further study of long-term results in larger number of patients is necessary.

  1. EMPREGO DE STENTS CEREBRAIS NAS PATOLOGIAS CEREBROVASCULARES

    Directory of Open Access Journals (Sweden)

    Laís Rocha Lopes

    2015-06-01

    Full Text Available Objective: To understand the applicability and characteristics of the stents for the treatment of cerebrovascular pathologies in order to understand its viability for the therapy. Methods: Scientific articles were used based on electronic search as PubMed, Scientific Electronic Library Online (SciELO, Intechopen, Medscape. An international and up to date source of articles was used. Results: Cerebrovascular diseases have emerged as the second most important cause of mortality worldwide, from this principle we observe the importance of this study. Recently, as a solution form, stents have become a major treatment option for difficult and not feasible cerebral aneurysms single winding. Intracranial stents serve as a bridge to the neo-endothelialization by providing a reduction in blood flow into the aneurysm. The use of stents for treatment should be seriously analyzed according to their feasibility, the knowledge of the professional about their brands, features and deployment techniques, and theoretical part of the professional needs to have dexterity to the application of an intracranial stent. Conclusions: This review raises an awareness of this subject, starts from the concept of cerebrovascular disease and aneurysms as well as the genesis of the stents, progressing to elucidate all product brands and specific characteristics of each, ending with its applicability, as well as making clear the purpose and mechanism of stents.

  2. Targeting In-Stent-Stenosis with RGD- and CXCL1-Coated Mini-Stents in Mice.

    Directory of Open Access Journals (Sweden)

    Sakine Simsekyilmaz

    Full Text Available Atherosclerotic lesions that critically narrow the artery can necessitate an angioplasty and stent implantation. Long-term therapeutic effects, however, are limited by excessive arterial remodeling. We here employed a miniaturized nitinol-stent coated with star-shaped polyethylenglycole (star-PEG, and evaluated its bio-functionalization with RGD and CXCL1 for improving in-stent stenosis after implantation into carotid arteries of mice. Nitinol foils or stents (bare metal were coated with star-PEG, and bio-functionalized with RGD, or RGD/CXCL1. Cell adhesion to star-PEG-coated nitinol foils was unaltered or reduced, whereas bio-functionalization with RGD but foremost RGD/CXCL1 increased adhesion of early angiogenic outgrowth cells (EOCs and endothelial cells but not smooth muscle cells when compared with bare metal foils. Stimulation of cells with RGD/CXCL1 furthermore increased the proliferation of EOCs. In vivo, bio-functionalization with RGD/CXCL1 significantly reduced neointima formation and thrombus formation, and increased re-endothelialization in apoE-/- carotid arteries compared with bare-metal nitinol stents, star-PEG-coated stents, and stents bio-functionalized with RGD only. Bio-functionalization of star-PEG-coated nitinol-stents with RGD/CXCL1 reduced in-stent neointima formation. By supporting the adhesion and proliferation of endothelial progenitor cells, RGD/CXCL1 coating of stents may help to accelerate endothelial repair after stent implantation, and thus may harbor the potential to limit the complication of in-stent restenosis in clinical approaches.

  3. Targeting In-Stent-Stenosis with RGD- and CXCL1-Coated Mini-Stents in Mice.

    Science.gov (United States)

    Simsekyilmaz, Sakine; Liehn, Elisa A; Weinandy, Stefan; Schreiber, Fabian; Megens, Remco T A; Theelen, Wendy; Smeets, Ralf; Jockenhövel, Stefan; Gries, Thomas; Möller, Martin; Klee, Doris; Weber, Christian; Zernecke, Alma

    2016-01-01

    Atherosclerotic lesions that critically narrow the artery can necessitate an angioplasty and stent implantation. Long-term therapeutic effects, however, are limited by excessive arterial remodeling. We here employed a miniaturized nitinol-stent coated with star-shaped polyethylenglycole (star-PEG), and evaluated its bio-functionalization with RGD and CXCL1 for improving in-stent stenosis after implantation into carotid arteries of mice. Nitinol foils or stents (bare metal) were coated with star-PEG, and bio-functionalized with RGD, or RGD/CXCL1. Cell adhesion to star-PEG-coated nitinol foils was unaltered or reduced, whereas bio-functionalization with RGD but foremost RGD/CXCL1 increased adhesion of early angiogenic outgrowth cells (EOCs) and endothelial cells but not smooth muscle cells when compared with bare metal foils. Stimulation of cells with RGD/CXCL1 furthermore increased the proliferation of EOCs. In vivo, bio-functionalization with RGD/CXCL1 significantly reduced neointima formation and thrombus formation, and increased re-endothelialization in apoE-/- carotid arteries compared with bare-metal nitinol stents, star-PEG-coated stents, and stents bio-functionalized with RGD only. Bio-functionalization of star-PEG-coated nitinol-stents with RGD/CXCL1 reduced in-stent neointima formation. By supporting the adhesion and proliferation of endothelial progenitor cells, RGD/CXCL1 coating of stents may help to accelerate endothelial repair after stent implantation, and thus may harbor the potential to limit the complication of in-stent restenosis in clinical approaches.

  4. A Novel method for modeling the recoil in W boson events at hadron collider

    Energy Technology Data Exchange (ETDEWEB)

    Abazov, Victor Mukhamedovich; /Dubna, JINR; Abbott, Braden Keim; /Oklahoma U.; Abolins, Maris A.; /Michigan State U.; Acharya, Bannanje Sripath; /Tata Inst.; Adams, Mark Raymond; /Illinois U., Chicago; Adams, Todd; /Florida State U.; Aguilo, Ernest; /Alberta U. /Simon Fraser U. /York U., Canada /McGill U.; Ahsan, Mahsana; /Kansas State U.; Alexeev, Guennadi D.; /Dubna, JINR; Alkhazov, Georgiy D.; /St. Petersburg, INP; Alton, Andrew K.; /Michigan U. /Augustana Coll., Sioux Falls /Northeastern U.

    2009-07-01

    We present a new method for modeling the hadronic recoil in W {yields} {ell}{nu} events produced at hadron colliders. The recoil is chosen from a library of recoils in Z {yields} {ell}{ell} data events and overlaid on a simulated W {yields} {ell}{nu} event. Implementation of this method requires that the data recoil library describe the properties of the measured recoil as a function of the true, rather than the measured, transverse momentum of the boson. We address this issue using a multidimensional Bayesian unfolding technique. We estimate the statistical and systematic uncertainties from this method for the W boson mass and width measurements assuming 1 fb{sup -1} of data from the Fermilab Tevatron. The uncertainties are found to be small and comparable to those of a more traditional parameterized recoil model. For the high precision measurements that will be possible with data from Run II of the Fermilab Tevatron and from the CERN LHC, the method presented in this paper may be advantageous, since it does not require an understanding of the measured recoil from first principles.

  5. Retrograde Colonic Stent Implantation Assisted by Percutaneous Colostomy: A Case Report

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Hyoung Gun; Han, Hyun Young; Chun, Tong Jin [Eulji Medical Center, Seoul (Korea, Republic of)

    2009-10-15

    We present a patient with disseminated pancreatic cancer who presented with symptoms of acute obstruction of the sigmoid colon. It was not possible to pass the region of the obstruction with a guide wire under colonoscopy and fluoroscopy. Consequently retrograde implantation of stents was performed successfully with the assistance of a minimally-sized colostomy when compared with a previously described procedure in the literature.

  6. Trajectory surgical guide stent for implant placement.

    Science.gov (United States)

    Adrian, E D; Ivanhoe, J R; Krantz, W A

    1992-05-01

    This article describes a new implant placement surgical guide that gives both implant location and trajectory to the surgeon. Radiopaque markers are placed on diagnostic dentures and a lateral cephalometric radiograph is made that shows the osseous anatomy at the symphysis and the anterior tooth location. The ideal implant location and trajectory data are transferred to a surgical stent that programs the angle and location of the fixtures at time of surgery. The stent has the additional benefit of acting as an occlusion rim, a mouth prop, and tongue retractor. Use of this stent has resulted in consistently programming the placement of implant fixtures that are prosthodontically ideal.

  7. Carotid Stent Fracture from Stylocarotid Syndrome

    Science.gov (United States)

    Hooker, Jeffrey D; Joyner, David A; Farley, Edward P; Khan, Majid

    2016-01-01

    Eagle syndrome is a rare condition resulting from elongation of the temporal styloid process or calcification of its associated stylohyoid ligaments. Although usually presenting with pain or odynophagia, Eagle syndrome has been reported to cause a multitude of neurologic symptoms or vascular complications, some of which can be life-threatening. We present a case in which an endovascularly placed internal carotid artery stent in close proximity to a calcified stylohyoid ligament resulted in stent fracture with subsequent stent and vessel occlusion. We review and discuss the presentation, diagnosis, etiology, complications and treatment options of the syndrome.

  8. The current status of stenting pathobiology.

    Science.gov (United States)

    Fleser, A; Leclerc, G

    1997-01-01

    Stents permanently maximize the arterial lumen following percutaneous transluminal coronary angioplasty (PTCA) at the cost of a vascular injury caused by the deployment of the prosthesis. Even though clinical trials show progressive reduction of restenosis and thrombosis rates in implanted coronary stents, these two events continue to represent a potential limitation to their clinical use. This review is focused on the arterial pathobiology related to the use of permanent and temporary stents. © 1997, Elsevier Science Inc. (Trends Cardiovasc Med 1997;7:24-28).

  9. Efficacy and safety of drug-eluting stent implantation for the treatment of in-stent restenosis occurring within bare-metal stent and drug-eluting stent*

    OpenAIRE

    Ge, Heng; Zhang, Qing; Zhou, Wei; He, Qing; Han, Zhi-hua; He, Ben

    2010-01-01

    Objective: Although drug-eluting stent (DES) implantation is the primary treatment modality for bare-metal stent (BMS) in-stent restenosis (ISR), little is known about the efficacy and safety profile of DES in the treatment of DES-ISR. The goal of this study was to compare the clinical outcomes following DES treatment for BMS-ISR and DES-ISR. Methods: Rates of major adverse cardiac events (MACE) were compared in 97 consecutive patients who underwent DES implantation for the treatment of ISR (...

  10. Paraffin processing of stented arteries using a postfixation dissolution of metallic and polymeric stents.

    Science.gov (United States)

    Fishbein, Ilia; Welch, Tre; Guerrero, David T; Alferiev, Ivan S; Adamo, Richard F; Chorny, Michael; Gupte, Rohit K; Tang, Yanqing; Levy, Robert J

    Studying the morphology of the arterial response to endovascular stent implantation requires embedding the explanted stented artery in rigid materials such as poly(methyl methacrylate) to enable sectioning through both the in situ stent and the arterial wall, thus maintaining the proper anatomic relationships. This is a laborious, time-consuming process. Moreover, the technical quality of stained plastic sections is typically suboptimal and, in some cases, precludes immunohistochemical analysis. Here we describe a novel technique for dissolution of metallic and plastic stents that is compatible with subsequent embedding of "destented" arteries in paraffin, fine sectioning, major staining protocols, and immunohistochemistry.

  11. Patient selection reduces thrombotic complications of emergent stenting for failed PTCA.

    Science.gov (United States)

    Herrmann, H C; Malosky, S A; Guidera, S A; DeAngelo, D; Hirshfeld, J W

    1995-04-01

    A comparison of consecutive initial and later patients receiving emergent coronary artery stents to salvage failed PTCA procedures was made to determine whether experience with this procedure can improve patient outcome. Twenty-six consecutive patients underwent emergent, unplanned implantation of one or more Palmaz-Schatz coronary stents at our institution over a 3-1/2 year period. Indications for stent insertion included impending vessel closure (decrease in TIMI flow grade and clinical evidence of ischemia) or acute occlusion (TIMI flow grade 0 or 1 and > or = 99% stenosis) after PTCA. Immediate and final success (30 day) were determined, and the results in the first (Initial) 13 patients were compared to the remaining (Later) 13 patients. Baseline characteristics of the study population included a male predominance (69%) with a mean (+/- SD) age of 57 +/- 10 years. Conventional balloon PTCA was performed in all three native coronary arteries with an increase in mean percentage stenosis from 76 +/- 13 to 85 +/- 14% (P < 0.05). Twelve patients developed acute occlusion and 14 patients impending closure after PTCA due to the appearance of thrombus (12%), dissection (46%), or both (35%). Palmaz-Schatz stents were successfully inserted in all patients restoring TIMI grade 3 antegrade flow; however, major complications developed in almost 50% of patients. Comparison of initial and later patients showed no differences in demographic or pre-PTCA angiographic characteristics. Later patients had less severe stenoses post-PTCA (before stenting) and were less likely to have thrombus present at the angioplasty site (15% vs. 77%, P < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

  12. Management of malignant biliary obstruction: Technical and clinical results using an expanded polytetrafluoroethylene fluorinated ethylene propylene (ePTFE/FEP)-covered metallic stent after 6-year experience

    Energy Technology Data Exchange (ETDEWEB)

    Fanelli, Fabrizio; Orgera, Gianluigi; Bezzi, Mario; Rossi, Plinio; Allegritti, Massimiliano; Passariello, Roberto [University of Rome, Department of Radiological Sciences, Rome (Italy)

    2008-05-15

    To evaluate the efficacy and safety of an expanded polytetrafluoroethylene-fluorinated ethylene-propylene (ePTFE/FEP)-covered metallic stent in the management of malignant biliary obstruction. Eighty consecutive patients with malignant common bile duct strictures were treated by placement of 83 covered metallic stents. The stent-graft consists of an inner ePTFE/FEP lining and an outer supporting structure of nitinol wire. Clinical evaluation, assessment of serum bilirubin and liver enzyme levels were analyzed before biliary drainage, before stent-graft placement and during the follow-up period at 1, 3, 6, 9 and 12 months. Technical success was obtained in all cases. After a mean follow-up of 6.9{+-}4.63 months, the 30-day mortality rate was 14.2%. Survival rates were 40% and 20.2% at 6 and 12 months, respectively. Stent-graft patency rates were 95.5%, 92.6% and 85.7% at 3, 6 and 12 months, respectively. Complications occurred in five patients (6.4%); among these, acute cholecystitis was observed in three patients (3.8%). A stent-graft occlusion rate of 9% was observed. The percentage of patients undergoing lifetime palliation (91%) and the midterm patency rate suggest that placement of this ePTFE/FEP-covered stent-graft is safe and highly effective in achieving biliary drainage in patients with malignant strictures of the common bile duct. (orig.)

  13. Nuclear recoil energy scale in liquid xenon with application to the direct detection of dark matter

    Energy Technology Data Exchange (ETDEWEB)

    Sorensen, P; Dahl, C E

    2011-02-14

    We show for the first time that the quenching of electronic excitation from nuclear recoils in liquid xenon is well-described by Lindhard theory, if the nuclear recoil energy is reconstructed using the combined (scintillation and ionization) energy scale proposed by Shutt et al.. We argue for the adoption of this perspective in favor of the existing preference for reconstructing nuclear recoil energy solely from primary scintillation. We show that signal partitioning into scintillation and ionization is well-described by the Thomas-Imel box model. We discuss the implications for liquid xenon detectors aimed at the direct detection of dark matter.

  14. Scintillation yield and time dependence from electronic and nuclear recoils in liquid neon

    CERN Document Server

    Lippincott, W H; Gastler, D; Kearns, E; McKinsey, D N; Nikkel, J A

    2011-01-01

    We have performed measurements of scintillation light in liquid neon, observing a signal yield in our detector as high as (3.5 $\\pm$ 0.4) photoelectrons/keV. We measure pulse shape discrimination efficiency between electronic and nuclear recoils in liquid neon from 50 and 300 keV nuclear recoil energy. We also measure the \\leff\\, parameter in liquid neon between 30 and 370 keV nuclear recoil energy, observing an average \\leff$=0.24$ above 50 keV. We observe a dependence of the scintillation time distribution and signal yield on the pressure and temperature of the liquid neon.

  15. Development and assessment of 316LVM cardiovascular stents

    Energy Technology Data Exchange (ETDEWEB)

    Raval, Ankur [Research and Development Division, Sahajanand Medical Technologies, Surat 395003 (India)]. E-mail: ankur.med@sahmed.com; Choubey, Animesh [Research and Development Division, Sahajanand Medical Technologies, Surat 395003 (India); Engineer, Chhaya [Research and Development Division, Sahajanand Medical Technologies, Surat 395003 (India); Kothwala, Devesh [Research and Development Division, Sahajanand Medical Technologies, Surat 395003 (India)

    2004-11-25

    One of the most common causes for heart failure is vasoconstriction. The medical procedure for alleviating vasoconstriction, angioplasty, calls for intracoronary stents. And the manufacture of intracoronary stents demands absolutely unmatched precision. Current study investigates CNC controlled pulsed Nd:YAG (neodymium:yttrium aluminium garnet) laser for cutting complex geometry of a stent on 316LVM tubings. It has been shown that surface quality of cardiovascular stents has a significant influence on biocompatibility. Therefore, optimal method and parameters for acid pickling of these slotted tube laser cut stents were explored, as a pretreatment for electropolishing. Pickling was necessary prior to electropolishing for removing the oxide films covering the stent surface. An optimal condition for electrochemical polishing could also be established and it caused a smooth stent surface. Passivation of these electropolished stents was done. Furthermore, materials characterization of stents was performed by means of composition and microstructural analysis.

  16. Mechanical design of an intracranial stent for treating cerebral aneurysms.

    Science.gov (United States)

    Shobayashi, Yasuhiro; Tanoue, Tetsuya; Tateshima, Satoshi; Tanishita, Kazuo

    2010-11-01

    Endovascular treatment of cerebral aneurysms using stents has advanced markedly in recent years. Mechanically, a cerebrovascular stent must be very flexible longitudinally and have low radial stiffness. However, no study has examined the stress distribution and deformation of cerebrovascular stents using the finite element method (FEM) and experiments. Stents can have open- and closed-cell structures, and open-cell stents are used clinically in the cerebrovasculature because of their high flexibility. However, the open-cell structure confers a risk of in-stent stenosis due to protrusion of stent struts into the normal parent artery. Therefore, a flexible stent with a closed-cell structure is required. To design a clinically useful, highly flexible, closed-cell stent, one must examine the mechanical properties of the closed-cell structure. In this study, we investigated the relationship between mesh patterns and the mechanical properties of closed-cell stents. Several mesh patterns were designed and their characteristics were studied using numerical simulation. The results showed that the bending stiffness of a closed-cell stent depends on the geometric configuration of the stent cell. It decreases when the stent cell is stretched in the circumferential direction. Mechanical flexibility equal to an open-cell structure was obtained in a closed-cell structure by varying the geometric configuration of the stent cell.

  17. Very late stent thrombosis following the placement of a crossing Y-stent with dual closed-cell stents for the coiling of a wide-necked aneurysm.

    Science.gov (United States)

    Lee, Chang-Young; Kim, Chang-Hyun

    2015-02-01

    The crossing Y-stent technique is a viable option for coiling of wide-necked bifurcation aneurysms. However, little is known about the long-term impact of this technique. Very late (>1 year) stent thrombosis following the placement of a crossing Y-stent with dual closed-cell stents for the coiling of a wide-necked basilar tip aneurysm, which has not been reported to date, is described.

  18. Comparison of short-term outcomes after carotid artery stenting according to different stent designs

    Science.gov (United States)

    Açar, Göksel; Özkan, Birol; Alıcı, Gökhan; Yazıcıoglu, Mehmet Vefik; Bulut, Mustafa; Kalkan, Mehmet Emin; Demir, Serdar; Acar, Rezzan Deniz; Boztosun, Bilal

    2013-01-01

    Introduction In the developed countries, stroke is the third most common cause of death. There are many data indicating that stents reduce the risk of embolism but there are few publications assessing whether different stent designs can influence the periprocedural complications. Aim To determine the effects of open- and closed-cell stent designs on 1-month results of carotid artery stenting (CAS). Material and methods The study group consisted of 290 consecutive patients (216 men and 74 women, mean age 66.6 ±8.7 years). Neuroprotection with a distal protection device was used in all cases. The patients were divided into two groups: the open-cell stent group (n = 144) and the closed-cell stent group (n = 138). Major adverse cardiac and cerebrovascular events (MACCE) described as myocardial infarction, stroke and death within 1 month were recorded and analysed subsequently. Periprocedural hypotension and transient cerebral ischaemia at 1 month after the CAS procedure were also assessed. Results We treated 290 carotid stenoses and stents were implanted in all patients. Fifteen patients (5.5%) were treated by staged CAS due to bilateral carotid artery disease. The technical success rate was 97.2%. There was no difference in the MACCE and transient cerebral ischaemia rate at 1 month between the two groups (p = 0.44 and p = 0.94, respectively). The incidence of ischaemic stroke was lower in the closed-cell stent group (2.77% vs. 0%; p = 0.04). The periprocedural rate of hypotension was higher in the closed-cell stent group (2.1% vs. 7.2%; p = 0.04). Conclusions Closed-cell stents are associated with a low rate of ischaemic stroke. We think that closed-cell stents may be preferred in patients at high risk of embolism. PMID:24570703

  19. 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.

  20. Prior chronic clopidogrel therapy is associated with increased adverse events and early stent thrombosis.

    Science.gov (United States)

    Asher, Elad; Fefer, Paul; Sabbag, Avi; Herscovici, Romana; Regev, Ehud; Mazin, Israel; Shlomo, Nir; Zahger, Doron; Atar, Shaul; Hammerman, Haim; Polak, Arthur; Beigel, Roy; Matetzky, Shlomi

    2016-01-01

    Despite the growing use of clopidogrel, limited data exist regarding the prognostic significance of chronic clopidogrel therapy in patients sustaining acute coronary syndrome (ACS). Our aim was to determine whether patients sustaining ACS while on chronic clopidogrel therapy have a worse prognosis than clopidogrel-naïve patients. A total of 5,386 consecutive ACS patients were prospectively characterised and followed-up for 30 days. Of them, 680 (13%) were treated with clopidogrel prior to the index ACS. Major adverse cardiovascular events (MACE) were defined as death, recurrent ACS, stroke and/or stent thrombosis. Compared with clopidogrel-naïve, chronic clopidogrel-treated patients were older (66 ± 12 vs 63 ± 13, respectively; pclopidogrel therapy was associated with a two-fold increase in in-hospital (1.6% vs 0.6%, respectively; p =0.006) as well as 30-day stent thrombosis (2.2% vs 1.0%, respectively; p=0.007). MACE at 30 days was also higher among chronic clopidogrel-treated compared with clopidogrel-naïve patients [12.3% vs 9.4%, respectively; pclopidogrel treatment was an independent predictor of stent thrombosis [OR=2.6 (95%CI 1.2-5.6), p=0.001]. Patients sustaining ACS while on chronic clopidogrel treatment are at higher risk for in-hospital and 30-day adverse outcomes, including stent thrombosis.

  1. Fast thermometry for trapped atoms using recoil-induced resonance

    Science.gov (United States)

    Zhao, Yan-Ting; Su, Dian-Qiang; Ji, Zhong-Hua; Zhang, Hong-Shan; Xiao, Lian-Tuan; Jia, Suo-Tang

    2015-09-01

    We have employed recoil-induced resonance (RIR) with linewidth on the order of 10 kHz to demonstrate the fast thermometry for ultracold atoms. We theoretically calculate the absorption spectrum of RIR which agrees well with the experimental results. The temperature of the ultracold sample derived from the RIR spectrum is T = 84±4.5 μK, which is close to 85 μK that measured by the method of time-of-flight absorption imaging. To exhibit the fast measurement advantage in applying RIR to the ultracold atom thermometry, we study the dependence of ultracold sample temperature on the trapping beam frequency detuning. This method can be applied to determine the translational temperature of molecules in photoassociation dynamics. Project supported by the National Basic Research Development Program of China (Grant No. 2012CB921603), the National High Technology Research and Development Program of China (Grant No. 2011AA010801), the National Natural Science Foundation of China (Grant Nos. 61275209, 11304189, 61378015, and 11434007), and Program for Changjiang Scholars and Innovative Research Team in Universities of China (Grant No. IRT13076).

  2. First Measurement of Beam-Recoil Observables Cx and Cz

    Energy Technology Data Exchange (ETDEWEB)

    R. Bradford; R.A. Schumacher; G. Adams; M.J. Amaryan; P. Ambrozewicz; E. Anciant; M. Anghinolfi; B. Asavapibhop; G. Asryan; G. Audit; H. Avakian; H. Bagdasaryan; N. Baillie; J.P. Ball; N.A. Baltzell; S. Barrow; V. Batourine; M. Battaglieri; K. Beard; I. Bedlinskiy; M. Bektasoglu; M. Bellis; N. Benmouna; B.L. Berman; N. Bianchi; A.S. Biselli; B.E. Bonner; S. Bouchigny; S. Boiarinov; D. Branford; W.J. Briscoe; W.K. Brooks; S. B¨ultmann; V.D. Burkert; C. Butuceanu; J.R. Calarco; S.L. Careccia; D.S. Carman; B. Carnahan; S. Chen; P.L. Cole; A. Coleman; P. Collins; P. Coltharp; D. Cords; † P. Corvisiero; D. Crabb; H. Crannell; V. Crede; J.P. Cummings; R. De Masi; E. De Sanctis; R. De Vita; P.V. Degtyarenko; H. Denizli; L. Dennis; A. Deur; K.V. Dharmawardane; R. Dickson; C. Djalali; G.E. Dodge; J. Donnelly; D. Doughty; P. Dragovitsch; M. Dugger; S. Dytman; O.P. Dzyubak; H. Egiyan; ; K.S. Egiyan; L. El Fassi; L. Elouadrhiri; A. Empl; P. Eugenio; R. Fatemi; G. Fedotov; G. Feldman; R.J. Feuerbach; T.A. Forest; H. Funsten; M. Garcon; G. Gavalian; ; G.P. Gilfoyle; K.L. Giovanetti; F.X. Girod; J.T. Goetz; A. Gonenc; R.W. Gothe; K.A. Griffioen; M. Guidal; M. Guillo; N. Guler; L. Guo; V. Gyurjyan; C. Hadjidakis; K. Hafidi; H. Hakobyan; R.S. Hakobyan; J. Hardie; D. Heddle; F.W. Hersman; K. Hicks; I. Hleiqawi; M. Holtrop; J. Hu; M. Huertas; C.E. Hyde-Wright; Y. Ilieva; D.G. Ireland; B.S. Ishkhanov; E.L. Isupov; M.M. Ito; D. Jenkins; H.S. Jo; K. Joo; H.G. Juengst; N. Kalantarians; J.D. Kellie; M. Khandaker; K.Y. Kim; K. Kim; W. Kim; A. Klein; F.J. Klein; M. Klusman; M. Kossov; L.H. Kramer; V. Kubarovsky; J. Kuhn; S.E. Kuhn; S.V. Kuleshov; J. Lachniet; J.M. Laget; J. Langheinrich; D. Lawrence; A.C.S. Lima; K. Livingston; H.Y. Lu; K. Lukashin; M. MacCormick; J.J. Manak; C. Marchand; N. Markov; S. McAleer; B. McKinnon; J.W.C. McNabb; B.A. Mecking; M.D. Mestayer; C.A. Meyer; T. Mibe; K. Mikhailov; M. Mirazita; R. Miskimen; V. Mokeev; K. Moriya; S.A. Morrow; M. Moteabbed; V. Muccifora; J. Mueller; G.S. Mutchler; P. Nadel-Turonski; J. Napolitano; R. Nasseripour; N. Natasha; S. Niccolai; G. Niculescu; I. Niculescu; B.B. Niczyporuk; M.R. Niroula; R.A. Niyazov; M. Nozar; G.V. O’Rielly; M. Osipenko; A.I. Ostrovidov; K. Park; E. Pasyuk; C. Paterson; S.A. Philips; J. Pierce; N. Pivnyuk; D. Pocanic; O. Pogorelko; E. Polli; I. Popa; S. Pozdniakov; B.M. Preedom; J.W. Price; Y. Prok; D. Protopopescu; L.M. Qin; B.P. Quinn; B.A. Raue; G. Riccardi; G. Ricco; M. Ripani; B.G. Ritchie; F. Ronchetti; G. Rosner; P. Rossi; D. Rowntree; P.D. Rubin; F. Sabatie; J. Salamanca; C. Salgado; J.P. Santoro; ; V. Sapunenko; V.S. Serov; A. Shafi; Y.G. Sharabian; J. Shaw; N.V. Shvedunov; S. Simionatto; A.V. Skabelin; E.S. Smith; L.C. Smith; D.I. Sober; D. Sokhan; M. Spraker; A. Stavinsky; S.S. Stepanyan; S. Stepanyan; B.E. Stokes; P. Stoler; I.I. Strakovsky; S. Strauch; M. Taiuti; S. Taylor; D.J. Tedeschi; U. Thoma; R. Thompson; A. Tkabladze; S. Tkachenko; L. Todor; C. Tur; M. Ungaro; M.F. Vineyard; A.V. Vlassov; K. Wang; D.P. Watts; L.B. Weinstein; H. Weller; D.P. Weygand; M. Williams; E. Wolin; M.H. Wood; A. Yegneswaran; J. Yun; L. Zana; J. Zhang; B. Zhao; and Z.W. Zhao

    2007-03-01

    Spin transfer from circularly polarized real photons to recoiling hyperons has been measured for the reactions $\\vec\\gamma + p \\to K^+ + \\vec\\Lambda$ and $\\vec\\gamma + p \\to K^+ + \\vec\\Sigma^0$. The data were obtained using the CLAS detector at Jefferson Lab for center-of-mass energies $W$ between 1.6 and 2.53 GeV, and for $-0.85<\\cos\\theta_{K^+}^{c.m.}< +0.95$. For the $\\Lambda$, the polarization transfer coefficient along the photon momentum axis, $C_z$, was found to be near unity for a wide range of energy and kaon production angles. The associated transverse polarization coefficient, $C_x$, is smaller than $C_z$ by a roughly constant difference of unity. Most significantly, the {\\it total} $\\Lambda$ polarization vector, including the induced polarization $P$, has magnitude consistent with unity at all measured energies and production angles when the beam is fully polarized. For the $\\Sigma^0$ this simple phenomenology does not hold. All existing hadrodynamic models are in poor agreement with these results.

  3. Superconducting Nuclear Recoil Sensor for Directional Dark Matter Detection

    Science.gov (United States)

    Junghans, Ann; Baldwin, Kevin; Hehlen, Markus; Lafler, Randy; Loomba, Dinesh; Phan, Nguyen; Weisse-Bernstein, Nina

    The Universe consists of 72% dark energy, 23% dark matter and only 5% of ordinary matter. One of the greatest challenges of the scientific community is to understand the nature of dark matter. Current models suggest that dark matter is made up of slowly moving, weakly interacting massive particles (WIMPs). But detecting WIMPs is challenging, as their expected signals are small and rare compared to the large background that can mimic the signal. The largest and most robust unique signature that sets them apart from other particles is the day-night variation of the directionality of dark matter on Earth. This modulation could be observed with a direction-sensitive detector and hence, would provide an unambiguous signature for the galactic origin of WIMPs. There are many studies underway to attempt to detect WIMPs both directly and indirectly, but solid-state WIMP detectors are widely unexplored although they would present many advantages to prevalent detectors that use large volumes of low pressure gas. We present first results of a novel multi-layered architecture, in which WIMPs would interact primarily with solid layers to produce nuclear recoils that then induce measureable voltage pulses in adjacent superconductor layers. This work was supported by the U.S. Department of Energy through the LANL Laboratory Directed Research and Development Program.

  4. Observation of the Dependence of Scintillation from Nuclear Recoils in Liquid Argon on Drift Field

    CERN Document Server

    Alexander, T; Cao, H; Cocco, A G; DeJongh, F; Fiorillo, G; Galbiati, C; Ghag, C; Grandi, L; Kendziora, C; Lippincott, W H; Loer, B; Love, C; Manenti, L; Martoff, C J; Meng, Y; Montanari, D; Mosteiro, P; Olvitt, D; Pordes, S; Qian, H; Rossi, B; Saldanha, R; Tan, W; Tatarowicz, J; Walker, S; Wang, H; Watson, A W; Westerdale, S; Yoo, J

    2013-01-01

    We have exposed a dual-phase Liquid Argon Time Projection Chamber (LAr-TPC) to a low energy pulsed narrowband neutron beam, produced at the Notre Dame Institute for Structure and Nuclear Astrophysics to study the scintillation light yield of recoiling nuclei in a LAr-TPC. A liquid scintillation counter was arranged to detect and identify neutrons scattered in the LAr-TPC target and to select the energy of the recoiling nuclei. We report the observation of a significant dependence on drift field of liquid argon scintillation from nuclear recoils of 11 keV. This observation is important because, to date, estimates of the sensitivity of noble liquid TPC dark matter searches are based on the assumption that electric field has only a small effect on the light yield from nuclear recoils.

  5. Recoil ion charge state distributions in low energy Ar{sup q+} {minus} Ar collisions

    Energy Technology Data Exchange (ETDEWEB)

    Vancura, J.; Marchetti, V.; Kostroun, V.O.

    1992-12-31

    We have measured the recoil ion charge state distributions in Ar{sup q+} -- Ar (8{le}q{le}16) collisions at 2.3 qkeV and 0.18qkeV by time of flight (TOF) spectroscopy. For Ar{sup 8-16+}, recoil ion charge states up to 6+ are clearly present, indicating that the 3p subshell in the target atom is being depleted, while for Ar{sup 10-16+}, there is evidence that target 3s electrons are also being removed. Comparison of the recoil ion charge state spectra at 2.3 and 0.18 qkeV shows that for a given projectile charge, there is very little dependence of the observed recoil target charge state distribution on projectile energy.

  6. Pulsar Recoil and Gravitational Radiation due to Asymetrical Stellar Collapse and Explosion

    Science.gov (United States)

    Burrows, Adam; Hayes, John C.

    1995-12-01

    New data imply that the average velocity of radio pulsars is high. Under the assumption that these data imply that a pulsar is born with an ``intrinsic'' kick, we investigate whether such kicks can be a consequence of asymmetrical collapse and explosion. We conclude that they can. The neutron star recoils in the direction opposite to that in which the ejecta preferentially emerge. In addition, we calculate the gravitational wave (GW) signature of such asymmetries due to anisotropic neutrino radiation and mass motions. We predict that any recoils imparted to the neutron star at birth will result in a gravitational wave strain, h() TT_zz, that does not go to zero with time. Hence, there may be a ``memory'' in the gravitational waveform from a protoneutron star that is correlated with its recoil and neutrino emissions. In principle, the recoil, neutrino emissions, and gravitational radiation can all be measured for a galactic supernova.

  7. About the importance of the nuclear recoil in \\alpha emission near the DNA

    CERN Document Server

    Rizzini, E Lodi; Corradini, M; Leali, M; Mascagna, V; Venturelli, L; Zurlo, N

    2011-01-01

    The effect of the energy deposition inside the human body made by radioactive substances is discussed. For the first time, we stress the importance of the recoiling nucleus in such reactions, particularly concerning the damage caused on the DNA structure.

  8. MIMAC low energy electron-recoil discrimination measured with fast neutrons

    CERN Document Server

    Riffard, Q; Guillaudin, O; Bosson, G; Bourrion, O; Bouvier, J; Descombes, T; Muraz, J -F; Lebreton, L; Maire, D; Colas, P; Giomataris, I; Busto, J; Fouchez, D; Brunner, J; Tao, C

    2016-01-01

    MIMAC (MIcro-TPC MAtrix of Chambers) is a directional WIMP Dark Matter detector project. Direct dark matter experiments need a high level of electron/recoil discrimination to search for nuclear recoils produced by WIMP-nucleus elastic scattering. In this paper, we proposed an original method for electron event rejection based on a multivariate analysis applied to experimental data acquired using monochromatic neutron fields. This analysis shows that a $10^{5}$ rejection power is reachable for electron/recoil discrimination. Moreover, the efficiency was estimated by a Monte-Carlo simulation showing that a $10^{5}$ electron rejection power is reached with a 85.1\\% nuclear recoil efficiency using the same detector gain that on the detectors running at Modane.

  9. Drug-eluting stents, restenosis and revascularization.

    Science.gov (United States)

    Ramcharitar, Steve; Gaster, Anne Louise; Daemen, Joost; Serruys, Patrick

    2007-06-01

    Several meta-analyses have demonstrated the superiority of drug-eluting stents (DES) in reducing the incidence of restenosis, target vessel revascularization and target lesion revascularization compared to their predecessor, the bare-metal stent. In comparing Cypher and Taxus stents, the two most recent meta-analyses have given the edge to the Cypher. However, it must be stressed that the superiority of one DES over another remains debatable due to ever changing "real-world data" compared to those attained from randomized trials. The newer sirolimus analogs and selective inhibitors are challenging the old guard in their quest to further limit restenosis. So too are the newer "high-tech" polymers and additionally by using more biodegradable material in the stent's design. Stents aimed at targeting lesions are a new armament in the battle against restenosis and together with combination therapies are exciting key areas to watch. The ideal way to treat a DES in-stent restenosis is still a challenge and hence the impetus is to avoid it from happening in the first place.

  10. Clinical Application of Stents in Digestive Diseases

    Institute of Scientific and Technical Information of China (English)

    GUAN Yongsong

    2002-01-01

    Objective To evaluate clinical application of therapeutic stenting of digestive diseases as a new approach from conventional management. Methods 115 cases of disorders in digestive system were managed with stents clinically, 148 procedures of intervention in all. The cases were suffering from portal hypertension of cirrhosis, post - operative esophageal stricture, Stricture resulted from esophageal carcinoma, Buddi - Chari syndrome, narrowing of superior mesentery arteries and biliary tract, etc. All had had the strictured or obliterated original natural tube lumen been dilated or recanalized under the guidance of monitoring of the fluoroscope before the stent placement except those receiving TIPS needing the creation of an artificial passage within the liver to place the stent. Results Therapeutic stenting achieves clinical effects completely different from conventional internal medicine and surgery such as portal hypertension by cirrhosis with esophageal varices, megalospleen, ascites improved; jaundis relived then resided and liver function improved and appetite better in postoperative stricture of bile duct; ascites and edema of lower limbs resided in Buddi - Chari syndrom; intestininal distention disappeared, appetite and digestive function improved in stricture in superior mesentery artery; and no dysphagia and easy food intake, appetite improved in patients of stricture of postoperative esophagus and stricture resulted from esophageal carcinoma. Conclusion Therapeutic stenting is clinically unique, dramatically effective, with minor risks and worthy promoting in the management of certain digestive disorders.

  11. 4D phase contrast flow imaging for in-stent flow visualization and assessment of stent patency in peripheral vascular stents – A phantom study

    Energy Technology Data Exchange (ETDEWEB)

    Bunck, Alexander C., E-mail: alexander.bunck@uk-koeln.de [Department of Clinical Radiology, University Hospital Münster, Albert-Schweitzer-Campus 1, Building A1, 48149 Muenster (Germany); Department of Radiology, University Hospital Cologne, Kerpener Strasse 62, 50937 Cologne (Germany); Jüttner, Alena, E-mail: alenajuettner@gmx.de [Department of Clinical Radiology, University Hospital Münster, Albert-Schweitzer-Campus 1, Building A1, 48149 Muenster (Germany); Kröger, Jan Robert, E-mail: jr.kroeger@uni-muenster.de [Department of Clinical Radiology, University Hospital Münster, Albert-Schweitzer-Campus 1, Building A1, 48149 Muenster (Germany); Burg, Matthias C., E-mail: m_burg03@uni-muenster.de [Department of Clinical Radiology, University Hospital Münster, Albert-Schweitzer-Campus 1, Building A1, 48149 Muenster (Germany); Kugel, Harald, E-mail: kugel@uni-muenster.de [Department of Clinical Radiology, University Hospital Münster, Albert-Schweitzer-Campus 1, Building A1, 48149 Muenster (Germany); Niederstadt, Thomas, E-mail: tnieders@uni-muenster.de [Department of Clinical Radiology, University Hospital Münster, Albert-Schweitzer-Campus 1, Building A1, 48149 Muenster (Germany); Tiemann, Klaus, E-mail: Klaus.Tiemann@ukmuenster.de [Department of Cardiology and Angiology, University Hospital Münster, Albert-Schweitzer-Campus 1, Building A1, 48149 Muenster (Germany); Schnackenburg, Bernhard, E-mail: bernhard.schnackenburg@philips.com [Philips Medical Systems DMC GmbH, Röntgenstraße 24, 22335 Hamburg (Germany); Crelier, Gerard R., E-mail: crelier@biomed.ee.ethz.ch [Institute for Biomedical Engineering, ETH and University of Zurich, ETZ F 95, Gloriastrasse 35, 8092 Zurich (Switzerland); and others

    2012-09-15

    Purpose: 4D phase contrast flow imaging is increasingly used to study the hemodynamics in various vascular territories and pathologies. The aim of this study was to assess the feasibility and validity of MRI based 4D phase contrast flow imaging for the evaluation of in-stent blood flow in 17 commonly used peripheral stents. Materials and methods: 17 different peripheral stents were implanted into a MR compatible flow phantom. In-stent visibility, maximal velocity and flow visualization were assessed and estimates of in-stent patency obtained from 4D phase contrast flow data sets were compared to a conventional 3D contrast-enhanced magnetic resonance angiography (CE-MRA) as well as 2D PC flow measurements. Results: In all but 3 of the tested stents time-resolved 3D particle traces could be visualized inside the stent lumen. Quality of 4D flow visualization and CE-MRA images depended on stent type and stent orientation relative to the magnetic field. Compared to the visible lumen area determined by 3D CE-MRA, estimates of lumen patency derived from 4D flow measurements were significantly higher and less dependent on stent type. A higher number of stents could be assessed for in-stent patency by 4D phase contrast flow imaging (n = 14) than by 2D phase contrast flow imaging (n = 10). Conclusions: 4D phase contrast flow imaging in peripheral vascular stents is feasible and appears advantageous over conventional 3D contrast-enhanced MR angiography and 2D phase contrast flow imaging. It allows for in-stent flow visualization and flow quantification with varying quality depending on stent type.

  12. A facility for heavy-ion elastic recoil detection analysis at the Australian National University

    Energy Technology Data Exchange (ETDEWEB)

    Timmers, H.; O`Connor, D.J. [Newcastle University, Newcastle, NSW (Australia). Dept. of Physics; Elliman, R.G.; Palmer, G.R.; Ophel, T.R. [Australian National University Canberra, ACT (Australia). Research School of Physical Sciences and Engineering

    1998-06-01

    The design of a facility at the Australian National University for heavy-ion elastic recoil detection analysis with minimal beam exposure is presented. The system is based on an established technique using a position-sensitive gas-ionisation detector with a large acceptance solid angle. The kinematic energy spread of the detected recoil ions is corrected. The capabilities of the system are discussed. (authors). 10 refs., 3 figs.

  13. Perturbative effects of spinning black holes with applications to recoil velocities

    CERN Document Server

    Nakano, Hiroyuki; Lousto, Carlos O; Zlochower, Yosef

    2010-01-01

    Recently, we proposed an enhancement of the Regge-Wheeler-Zerilli formalism for first-order perturbations about a Schwarzschild background that includes first-order corrections due to the background black-hole spin. Using this formalism, we investigate gravitational wave recoil effects from a spinning black-hole binary system analytically. This allows us to better understand the origin of the large recoils observed in full numerical simulation of spinning black hole binaries.

  14. Investigation on modeling and controability of a magnetorheological gun recoil damper

    Science.gov (United States)

    Hu, Hongsheng; Wang, Juan; Wang, Jiong; Qian, Suxiang; Li, Yancheng

    2009-07-01

    Magnetorheological (MR) fluid as a new smart material has done well in the vibration and impact control engineering fields because of its good electromechanical coupling characteristics, preferable dynamic performance and higher sensitivity. And success of MRF has been apparent in many engineering applied fields, such as semi-active suspension, civil engineering, etc. So far, little research has been done about MR damper applied into the weapon system. Its primary purpose of this study is to identify its dynamic performance and controability of the artillery recoil mechanism equipped with MR damper. Firstly, based on the traditional artillery recoil mechanism, a recoil dynamic model is developed in order to obtain an ideal rule between recoil force and its stroke. Then, its effects of recoil resistance on the stability and firing accuracy of artillery are explored. Because MR gun recoil damper under high impact load shows a typical nonlinear character and there exists a shear-thinning phenomenon, to establish an accurate dynamic model has been a seeking aim of its design and application for MR damper under high impact load. Secondly, in this paper, considering its actual bearing load, an inertia factor was introduced to Herschel-Bulkley model, and some factor's effect on damping force are simulated and analyzed by using numerical simulation, including its dynamic performance under different flow coefficients and input currents. Finally, both of tests with the fixed current and different On-Off control algorithms have been done to confirm its controability of MR gun recoil damper under high impact load. Experimental results show its dynamic performances of the large-scale single-ended MR gun recoil damper can be changed by altering the applied currents and it has a good controllability.

  15. Multivariate techniques of analysis for ToF-E recoil spectrometry data

    Energy Technology Data Exchange (ETDEWEB)

    Whitlow, H.J.; Bouanani, M.E.; Persson, L.; Hult, M.; Jonsson, P.; Johnston, P.N. [Lund Institute of Technology, Solvegatan, (Sweden), Department of Nuclear Physics; Andersson, M. [Uppsala Univ. (Sweden). Dept. of Organic Chemistry; Ostling, M.; Zaring, C. [Royal institute of Technology, Electrum, Kista, (Sweden), Department of Electronics; Johnston, P.N.; Bubb, I.F.; Walker, B.R.; Stannard, W.B. [Royal Melbourne Inst. of Tech., VIC (Australia); Cohen, D.D.; Dytlewski, N. [Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW (Australia)

    1996-12-31

    Multivariate statistical methods are being developed by the Australian -Swedish Recoil Spectrometry Collaboration for quantitative analysis of the wealth of information in Time of Flight (ToF) and energy dispersive Recoil Spectrometry. An overview is presented of progress made in the use of multivariate techniques for energy calibration, separation of mass-overlapped signals and simulation of ToF-E data. 6 refs., 5 figs.

  16. Six-month clinical outcomes of Firebird 2TM sirolimus-eluting stent implantation in real-world patients with coronary artery diseases

    Institute of Scientific and Technical Information of China (English)

    GE Jun-bo; ZHANG Feng; QIAN Ju-ying; GE Lei; LIU Xue-bo; ZHOU Jun

    2011-01-01

    Background The Firebird 2TM sirolimus-eluting stent (Firebird 2 stent) is a second-generation sirolimus-eluting stent which has a cobalt-chromium alloy stent platform, a brand new bracket structure, and two layers of styrene-butylenes-styrene polymer coatings with better biocompatibility. The Firebird 2TM cObalt-Chromium alloy sirolimus-elUting Stent registry (FOCUS registry) aimed to evaluate the safety and efficacy of the Firebird 2 stent in patients with coronary artery disease in daily practice.Methods The FOCUS registry is a prospective, non-randomized, international multi-center, single-arm clinical registry.Between March 2009 and February 2010, 5084 patients receiving at least 1 Firebird 2 stent during daily clinical practice at 83 medical centers were enrolled.Results Of the 5084 patients enrolled in the registry, 5077 and 5058 were respectively available for 30 days and 6 months follow-up. The 30-day rate of major adverse cardiac events (MACE) was 1.20%, including 13 cardiac deaths, 46 non-fatal myocardial infarction (MI), and 6 target vessel revascularization (TVR). At 6 months follow-up, the rate of MACE was 1.80%. There were 32 cardiac deaths, 48 non-fatal MI, and 15 TVR. According to the Academic Research Consortium definition, definite/probable stent thrombosis (ST) occurred in 0.43% (22/5058) of patients, including 8 cases of acute ST, 11 subacute ST, and 3 late ST.Conclusion The Firebird 2 stent showed the promising efficacy and safety at 30 days and 6 months in a real-world population of patients with coronary artery diseases.

  17. Frequency and consequences of early in-stent lesions after carotid artery stent placement.

    NARCIS (Netherlands)

    Jongen, L.M.; Hendrikse, J.; Waaijer, A.; Worp, H.B. van der; Leijdekkers, V.J.; Lo, R.T.; Mali, W.P.Th.; Prokop, M.

    2009-01-01

    PURPOSE: To examine the prevalence of in-stent lesions 1 month after carotid artery stent placement with multidetector computed tomography (CT) angiography and to evaluate their possible causes and their consequences during 1-year follow-up. MATERIALS AND METHODS: Sixty-nine patients with symptomati

  18. Technical options for treatment of in-stent restenosis after carotid artery stenting

    NARCIS (Netherlands)

    Pourier, Vanessa E C; de Borst, Gert J.

    2016-01-01

    Objective This review summarizes the available evidence and analyzes the current trends on treatments for carotid in-stent restenosis (ISR) after carotid artery stenting (CAS). Methods An update of a 2010 review of the literature (which included 20 articles) was conducted using PubMed and Embase. Al

  19. Computational Study of Axial Fatigue for Peripheral Nitinol Stents

    Science.gov (United States)

    Meoli, Alessio; Dordoni, Elena; Petrini, Lorenza; Migliavacca, Francesco; Dubini, Gabriele; Pennati, Giancarlo

    2014-07-01

    Despite their success as primary treatment for vascular diseases, Nitinol peripheral stents are still affected by complications related to fatigue failure. Hip and knee movements during daily activities produce large and cyclic deformations of the superficial femoral artery, that concomitant to the effects of pulsatile blood pressure, may cause fatigue failure in the stent. Fatigue failure typically occurs in cases of very extended lesions, which often require the use of two or more overlapping stents. In this study, finite element models were used to study the fatigue behavior of Nitinol stents when subjected to cyclic axial compression in different conditions. A specific commercial Nitinol stent was chosen for the analysis and subjected to cyclic axial compression typical of the femoral vascular region. Three different configurations were investigated: stent alone, stent deployed in a tube, and two overlapping stents deployed in a tube. Results confirm that stent oversizing has an influence in determining both the mean and amplitude strains induced in the stent and plays an important role in determining the fatigue response of Nitinol stents. In case of overlapping stents, numerical results suggest higher amplitude strains concentrate in the region close to the overlapping portion where the abrupt change in stiffness causes higher cyclic compression. These findings help to explain the high incidence of stent fractures observed in various clinical trials located close to the overlapping portion.

  20. Measurement of Scintillation and Ionization Yield and Scintillation Pulse Shape from Nuclear Recoils in Liquid Argon

    CERN Document Server

    Cao, H; Avetisyan, R; Back, H O; Cocco, A G; DeJongh, F; Fiorillo, G; Galbiati, C; Grandi, L; Guardincerri, Y; Kendziora, C; Lippincott, W H; Love, C; Lyons, S; Manenti, L; Martoff, C J; Meng, Y; Montanari, D; Mosteiro, P; Olvitt, D; Pordes, S; Qian, H; Rossi, B; Saldanha, R; Sangiorgio, S; Siegl, K; Strauss, S Y; Tan, W; Tatarowicz, J; Walker, S; Wang, H; Watson, A W; Westerdale, S; Yoo, J

    2014-01-01

    We have measured the scintillation and ionization yield of recoiling nuclei in liquid argon as a function of applied electric field by exposing a dual-phase Liquid Argon Time Projection Chamber (LAr-TPC) to a low energy pulsed narrowband neutron beam produced at the Notre Dame Institute for Structure and Nuclear Astrophysics. Liquid scintillation counters were arranged to detect and identify neutrons scattered in the TPC and to select the energy of the recoiling nuclei. We report measurements of the scintillation and ionization yields for nuclear recoils with energies from 10.3 to 57.2 keV and for applied electric fields from 0 to 1000 V/cm. We also report the observation of an anti-correlation between scintillation and ionization from nuclear recoils, which is similar to the anti-correlation between scintillation and ionization from electron recoils. A comparison of the light and charge yield of recoils parallel and perpendicular to the applied electric field yielded a first evidence of sensitivity to direct...

  1. Use of covered Cheatham-Platinum stent as the primary modality in the treatment for native coarctation of the aorta

    Institute of Scientific and Technical Information of China (English)

    CHANG Zong-ping; WU Wen-hui; HU Hai-bo; LI Shi-guo; YU Ji-hong; YAN Chao-wu; JIANG Shi-liang; XU Zhong-ying; ZHANG Ge-jun; HUANG Lian-jun; ZHAO Shi-hua; LING Jian; ZHENG Hong; JIN Jing-lin

    2012-01-01

    Background Bare stent implantation in the treatment for native and recurrent coarctation of the aorta (CoA) has become established as an alternative to surgery and balloon angioplasty.However,this modality still encounters significant complications during the procedure and/or follow-up.The covered Cheatham-Platinum (CP) stent commonly used to be chosen as a rescue treatment in these patients.The purpose of this study was to evaluate the use of covered CP stent as the primary modality in the treatment for native CoA.Methods Twenty-five covered CP stents and 2 bare CP stents were implanted in 25 patients with native CoA.All patients after the intervention were invited for follow-up examinations.Results The peak systolic gradient across the lesion decreased significantly from a median value of 67.5 mmHg (quartile range,19.3 mmHg) to 2 mmHg (quartile range,4.0 mmHg) (P <0.0001).Stenotic segment diameter increased from a median value of 5.0 mm (quartile range,1.5 mm) to 17.9 mm (quartile range,2.5 mm) (P <0.0001).The median ratio of diameter of the coarctation postprocedure to preprocedure was 4.2 (quartile range,1.6).All of the CP stents were placed in the suitable position without any acute complications.During a follow-up period of up to 72 months,no complications were encountered.Most of the patients (21/25) were normotensive,apart from four patients requiring antihypertensive medication during the follow-up.Conclusion The implantation of covered CP stent as the primary modality is safe and effective in the treatment for native CoA in adolescents and adults.

  2. M-Guard Stent in Stemi Patients with High Thrombus Burden Lesions: A Prospective, Single Arm Study

    Directory of Open Access Journals (Sweden)

    Mohammad Zade Shabestari M

    2014-04-01

    Full Text Available Introduction: Primary PCI is the preferred modality to restore blood perfusion in STEMI patients, but myocardial reperfusion is sometimes lower than optimal. Distal embolization seems to play the leading role. There is rare evidence suggestive of M-Guard stents; a recent innovation which protects against distal embolization may be beneficial in this circumstance. Materials and Methods:This was a prospective single arm study. Patients with acute STEMI admitted at the Cardiac Emergency Unit of Imam Reza Hospital from July 2011 to November  2012 who had a large bulk of thrombus in their angiogram, underwent M-Guard stenting and were followed up for six months for chest pain and secondary revascularization. Results: The 23 patients, aged between 34 and 84; 65.2%, were male and had undergone primary PCI, mechanical thrombus aspiration, and M-Guard stenting. Left Anterior Descending (LAD (63.9% and Right Coronary Artery (RCA (39.1% were most commonly involved. 78.2%, 13.1%, and 8.9% of patients had primary Thrombolysis in Myocardial Infarction (TIMI Thrombus grade five, four, and three. Among them, 86.9% achieved TIMI Flow grade three and 13.04% TIMI Flow grade two. The rate of transient "no-reflow" phenomenon was 21%. One patient died after stenting in the setting of cardiogenic shock. There was one case of in-stent restenosis five months after the procedure. Of the other 15 accessible patients, after six months, none experienced a second angioplasty or any ischemic symptoms. Conclusion: Using M-Guard stents in acute STEMI patients having undergone primary PCI with high thrombus burden is probably associated with lower rates of the "no-reflow" phenomenon and improved vessel reperfusion.  

  3. Estudo comparativo randomizado do implante de Stent de aço inoxidável recoberto por carbono semelhante ao diamante versus não recoberto em pacientes com doença arterial coronariana Randomized comparative study of diamond-like carbon coated stainless steel stent versus uncoated stent implantation in patients with coronary artery disease

    Directory of Open Access Journals (Sweden)

    George César Ximenes Meireles

    2007-04-01

    Full Text Available OBJETIVO: Comparar as taxas de reestenose e de eventos cardíacos maiores em um e seis meses pós-implante de stents recobertos com CSD com os não-recobertos. MÉTODOS: Estudo comparativo, prospectivo, randomizado, de 180 pacientes com diagnóstico de insuficiência coronária, submetidos a implante de stent recoberto com CSD (Phytis® ou stent não-recobertos (Penta®, no período de janeiro de 2003 a julho de 2004. Foram critérios de inclusão: lesão de novo com porcentual de estenose em diâmetro > 50% em artéria coronária com diâmetro de referência > 2,5 mm e OBJECTIVE: To compare restenosis and major cardiac event rates at one and six months after DLC-coated stent implantation with those of uncoated stents. METHODS: Randomized, prospective, comparative study of 180 patients with coronary insufficiency undergoing DLC coated stent (Phytis™ or uncoated stent (Penta™ implantation, from January, 2003 to July, 2004. Inclusion criteria were: de novo lesion with >50% diameter stenosis in a coronary artery with reference diameter > 2,5 mm and < 4 mm, and length < 20 mm. Exclusion criteria were: left main coronary artery and bifurcation lesions, chronic total occlusion, and in-stent restenosis. RESULTS: Clinical and angiographic baseline characteristics of the groups were similar. Procedural success was achieved in 98.9% of the patients in both groups. One cardiac death occurred in each group during hospitalization. Reference diameter and acute gain were greater in the Penta™ group (3.21±0.37 mm vs. 3.34±0.8 mm, p=0.02 and 2.3±0.5 vs. 2.49±0.5, p=0.009, respectively. Angiographic follow-up at six months showed similar rates of restenosis (24.3% vs. 21.8%, p=0.84 and of major cardiac events (16.8% vs. 17.5%, p=1. CONCLUSION: DLC coated stents did not provide better outcomes in relation to uncoated stents.

  4. Axial stent strut angle influences wall shear stress after stent implantation: analysis using 3D computational fluid dynamics models of stent foreshortening

    Directory of Open Access Journals (Sweden)

    Warltier David C

    2005-10-01

    Full Text Available Abstract Introduction The success of vascular stents in the restoration of blood flow is limited by restenosis. Recent data generated from computational fluid dynamics (CFD models suggest that the vascular geometry created by an implanted stent causes local alterations in wall shear stress (WSS that are associated with neointimal hyperplasia (NH. Foreshortening is a potential limitation of stent design that may affect stent performance and the rate of restenosis. The angle created between axially aligned stent struts and the principal direction of blood flow varies with the degree to which the stent foreshortens after implantation. Methods In the current investigation, we tested the hypothesis that stent foreshortening adversely influences the distribution of WSS and WSS gradients using time-dependent 3D CFD simulations of normal arteries based on canine coronary artery measurements of diameter and blood flow. WSS and WSS gradients were calculated using conventional techniques in ideal (16 mm and progressively foreshortened (14 and 12 mm stented computational vessels. Results Stent foreshortening increased the intrastrut area of the luminal surface exposed to low WSS and elevated spatial WSS gradients. Progressive degrees of stent foreshortening were also associated with strut misalignment relative to the direction of blood flow as indicated by analysis of near-wall velocity vectors. Conclusion The current results suggest that foreshortening may predispose the stented vessel to a higher risk of neointimal hyperplasia.

  5. Extent and distribution of in-stent intimal hyperplasia and edge effect in a non-radiation stent population.

    Science.gov (United States)

    Weissman, N J; Wilensky, R L; Tanguay, J F; Bartorelli, A L; Moses, J; Williams, D O; Bailey, S; Martin, J L; Canos, M R; Rudra, H; Popma, J J; Leon, M B; Kaplan, A V; Mintz, G S

    2001-08-01

    Intimal hyperplasia within the body of the stent is the primary mechanism for in-stent restenosis; however, stent edge restenosis has been described after brachytherapy. Our current understanding about the magnitude of in vivo intimal hyperplasia and edge restenosis is limited to data obtained primarily from select, symptomatic patients requiring repeat angiography. The purpose of this study was to determine the extent and distribution of intimal hyperplasia both within the stent and along the stent edge in relatively nonselect, asymptomatic patients scheduled for 6-month intravascular ultrasound (IVUS) as part of a multicenter trial: Heparin Infusion Prior to Stenting. Planar IVUS measurements 1 mm apart were obtained throughout the stent and over a length of 10 mm proximal and distal to the stent at index and follow-up. Of the 179 patients enrolled, 140 returned for repeat angiography and IVUS at 6.4 +/- 1.9 months and had IVUS images adequate for analysis. Patients had 1.2 +/- 0.6 Palmaz-Schatz stents per vessel. There was a wide individual variation of intimal hyperplasia distribution within the stent and no mean predilection for any location. At 6 months, intimal hyperplasia occupied 29.3 +/- 16.2% of the stent volume on average. Lumen loss within 2 mm of the stent edge was due primarily to intimal proliferation. Beyond 2 mm, negative remodeling contributed more to lumen loss. Gender, age, vessel location, index plaque burden, hypercholesterolemia, diabetes, and tobacco did not predict luminal narrowing at the stent edges, but diabetes, unstable angina at presentation, and lesion length were predictive of in-stent intimal hyperplasia. In a non-radiation stent population, 29% of the stent volume is filled with intimal hyperplasia at 6 months. Lumen loss at the stent edge is due primarily to intimal proliferation.

  6. A review on fracture prevention of stent in femoropopliteal artery

    Science.gov (United States)

    Atan, Bainun Akmal Mohd; Ismail, Al Emran; Taib, Ishkrizat; Lazim, Zulfaqih

    2017-01-01

    Heavily calcific lesions, total occlusions, tortuous blood vessels, variable lengths of arteries, various dynamic loads and deformations in the femoropopliteal (FP) arterial segment make stenosis treatments are complicated. The dynamic forces in FP artery including bending, torsion and radial compression may lead to stent fracture (SF) and eventually to in-stent restenosis (ISR). Stent design specifically geometrical configurations are a major factor need to be improved to optimize stent expansion and flexibility both bending and torsion during stent deployment into the diseased FP artery. Previous studies discovered the influence of various stent geometrical designs resulted different structural behaviour. Optimizing stent design can improve stent performances: flexibility and radial strength to prevent SF in FP arterial segment

  7. Direct drug-eluting stenting to reduce stent restenosis : a randomized comparison of direct stent implantation to conventional stenting with pre-dilation or provisional stenting in elective PCI patients

    NARCIS (Netherlands)

    Remkes, Wouter S; Somi, Samer; Roolvink, Vincent; Rasoul, Saman; Ottervanger, Jan Paul; Gosselink, A T Marcel; Hoorntje, Jan C A; Dambrink, Jan-Henk E; de Boer, Menko-Jan; Suryapranata, Harry; van 't Hof, Arnoud W J

    2014-01-01

    OBJECTIVES: The aim was to investigate whether a strategy of direct drug-eluting stent (DES) implantation without pre-dilation is associated with a reduced incidence of restenosis compared with CS with pre-dilation or provisional stenting (PS). BACKGROUND: Previous studies were performed comparing d

  8. Detection of exclusive reactions in the Hermes Recoil Fiber Tracker

    Energy Technology Data Exchange (ETDEWEB)

    Keri, Tibor

    2008-08-15

    the RD (Recoil Detector) with an unpolarized target at this position. This detector consists of the Silicon Strip Detector, the SFT (Scintillating Fiber Tracker), the Photon Detector and is surrounded by a 1T superconducting magnet. It provides several space points for tracking and thus momentum reconstruction. The energy deposition in the various detectors is used to achieve particle identification. The main part of the thesis work was the implementation of the SFT and the RD readout system. Before the installation of the RD a series of test runs were carried out to proof the concept of the detector, to measure the internal alignment and to prepare the installation. These test runs for the SFT are described and major results are shown. Furthermore a preliminary analysis of the latest data 06d/06d0 was carried out to show the performance of the installed Recoil Detector in combination with the HERMES forward spectrometer. (orig.)

  9. Metallic Stents for Tracheobronchial Pathology Treatment

    Energy Technology Data Exchange (ETDEWEB)

    Serrano, Carolina, E-mail: carolina.serrano@unizar.es [University of Zaragoza, Surgical Pathology Unit, Animal Pathology Department (Spain); Laborda, Alicia, E-mail: alaborda@unizar.es [University of Zaragoza, Minimally Invasive Techniques Research Group (GITMI) (Spain); Lozano, Juan M., E-mail: juamauloz@gmail.com [Marly Clinic, Radiology Department (Colombia); Caballero, Hugo, E-mail: hugocaballero2007@gmail.com [Marly Clinic, Pulmonology Department (Colombia); Sebastian, Antonio, E-mail: antonio.sebastian@ono.es [Lozano Blesa Clinical University Hospital, Pulmonology Department (Spain); Lopera, Jorge, E-mail: lopera@uthscsa.edu [Health Science Center, Interventional Radiology Deparment (United States); Gregorio, Miguel Angel de, E-mail: mgregori@unizar.es [University of Zaragoza, Minimally Invasive Techniques Research Group (GITMI) (Spain)

    2013-12-15

    Purpose: To present the 7-year experience of the treatment of benign and malignant tracheobronchial stenoses using metallic stents. Patients and Methods: One hundred twenty-three stents were inserted in 86 patients (74 benign and 12 malignant stenoses). Ninety-seven stents were placed in the trachea and 26 in the bronchi. The procedures were performed under fluoroscopic and flexible bronchoscopic guidance with the patient under light sedation. In cases of severe stenotic lesions or obstructions, laser resection was performed before stent placement. Clinical and functional pulmonary data were recorded before and 3 months after the procedure. Follow-up involved clinical data and radiographic techniques at 48 h and at 1-, 3-, 6-, and 12-month intervals. Results: The technical success was 100 %. Dyspnea disappearance, forced expiratory volume in the first second, and pulmonary functional data improvement was observed in all patients (p < 0.001). Complications were detected in 23 patients (26.7 %). Mean follow-up time was 6.3 {+-} 1.2 months in patients with malignant lesions and 76.2 {+-} 2.3 months patients with in benign lesions. By the end of the study, 100 % of patients with malignant pathology and 6.7 % of patients with benign lesions had died. Conclusion: Endoluminal treatment of tracheobronchial stenosis with metallic stents is a therapeutic alternative in patients who are poor candidates for surgery. In unresectable malignant lesions, the benefit of metallic stenting is unquestionable. In benign lesions, the results are satisfactory, but sometimes other interventions are required to treat complications. New stent technology may improve these results.

  10. Safety and Efficacy of Thoracic External Beam Radiotherapy After Airway Stenting in Malignant Airway Obstruction

    Energy Technology Data Exchange (ETDEWEB)

    Rochet, Nathalie, E-mail: nrochet@partners.org [Department of Radiation Oncology, University of Heidelberg, Heidelberg (Germany); Hauswald, Henrik; Schmaus, Martina; Hensley, Frank [Department of Radiation Oncology, University of Heidelberg, Heidelberg (Germany); Huber, Peter [Department of Radiotherapy, German Cancer Research Center, Heidelberg (Germany); Eberhardt, Ralf; Herth, Felix J. [Department of Pulmonology and Respiratory Care Medicine, Thoraxklinik at University of Heidelberg, Heidelberg (Germany); Debus, Juergen; Neuhof, Dirk [Department of Radiation Oncology, University of Heidelberg, Heidelberg (Germany)

    2012-05-01

    Purpose: We retrospectively evaluated the outcome and toxicity of external beam radiotherapy (EBRT) after airway stents were placed in patients treated for malignant airway obstruction. Methods and Materials: Between 2004 and 2009, we performed airway stenting followed by EBRT in 43 patients for symptomatic primary lung cancer (n = 31) or other thoracic malignancies (n = 12). The median time interval between stent placement and first irradiation was 14 days. A median total dose of 50 Gy was delivered. Sixty-seven percent of the patients had reduced performance status (Karnofsky performance score, {<=}70). Results: EBRT had to be stopped prematurely in 16 patients (37%), at a median total dose of 17 Gy, for various reasons. In this group of patients, the survival was poor, with a median overall survival (OS) of only 21 days. Twenty-seven patients (63%) completed radiotherapy as planned, with a median OS of 8.4 months. Fourteen of 43 patients (33%) developed at least one Common Terminology Criteria for Adverse Event of grade 3 to 5. The most common event was a malignant restenosis of the stent leading to asphyxia (n = 7), followed by fistula formation (n = 4), necrosis (n = 3), mediastinitis with abscess (n = 1), secondary nonmalignant airway stenosis (n = 1), and hemoptysis (n = 1). With the exception of one event, all events were associated with a local progression of the tumor. Conclusions: Although the long-term prognosis for patients with malignant airway obstruction is poor, airway stenting combined with EBRT offers a possible therapeutic option, achieving fast relief of acute respiratory distress with an associated antitumor effect, resulting in a potential survival benefit. However, due to local advanced tumor growth, increased rates of adverse events are to be expected, necessitating careful monitoring.

  11. Early local intracoronary platelet activation after drug-eluting stent placement

    Institute of Scientific and Technical Information of China (English)

    Ailiman Mahemuti; Nicolas Meneveau; Marie-France Seronde; Francois Schiele; Mariette Mercier; Evelyne Racadot; Jean-Pierre Bassand

    2007-01-01

    Background Early local platelet activation after coronary intervention identifies patients at increased risk of acute stent thrombosis (AST). However, early changes in platelet activation in coronary circulation following drug-eluting stent (DES) implantation have never been reported.Methods In a prospective study of 26 consecutive elective stable angina patients, platelet activation was analyzed by measuring soluble glycoprotein V (sGPV) and P-selectin (CD62P) before and after implantation of either DES or bare metal stent (BMS). All patients were pretreated with clopidogrel (300 mg loading dose) and aspirin (75 mg orally) the day before the procedure. Blood samples were drawn from the coronary ostium and 10 - 20 mm distal to the lesion site.Results Consistent with the lower baseline clinical risk, the levels of CD62P and sGPV were within normal reference range, both in the coronary ostium and distal to the lesion before percutaneous coronary intervention (PCl) procedure.The levels of CD62P and sGPV did not change significantly (CD62P: (31.1 ± 9.86) ng/ml vs (29.5 ± 9.02) ng/ml, P=0.319and sGPV: (52.4 ± 13.5) ng/ml vs (51.8 ± 11.7) ng/ml, P=0.674, respectively) after stent implantation when compared with baseline. Changes in these platelet activation markers did not differ between stent types.Conclusions Intracoronary local platelet activation does not occur in stable angina patients before and immediately following DES implantation when dual anti-platelet is administered.

  12. Simulation of stent deployment in a realistic human coronary artery

    NARCIS (Netherlands)

    F.J.H. Gijsen (Frank); F. Migliavacca (Francesco); S. Schievano (Silvia); L. Socci (Laura); L. Petrini (Lorenza); A. Thury (Attila); J.J. Wentzel (Jolanda); A.F.W. van der Steen (Ton); P.W.J.C. Serruys (Patrick); G. Dubini (Gabriele)

    2008-01-01

    textabstractBackground: The process of restenosis after a stenting procedure is related to local biomechanical environment. Arterial wall stresses caused by the interaction of the stent with the vascular wall and possibly stress induced stent strut fracture are two important parameters. The knowledg

  13. A simple technique to remove migrated esophageal stents.

    Science.gov (United States)

    Noyer, C M; Forohar, F

    1998-09-01

    A 51-yr-old man with a tracheoesophageal fistula from an esophageal carcinoma had two expandable covered stents placed, which migrated distally. After several unsuccessful attempts to remove the stents, we fashioned a homemade snare to entrap and remove the stents under endoscopic and fluoroscopic guidance.

  14. Modelling and simulating in-stent restenosis with complex automata

    NARCIS (Netherlands)

    Hoekstra, A.G.; Lawford, P.; Hose, R.

    2010-01-01

    In-stent restenosis, the maladaptive response of a blood vessel to injury caused by the deployment of a stent, is a multiscale system involving a large number of biological and physical processes. We describe a Complex Automata Model for in-stent restenosis, coupling bulk flow, drug diffusion, and s

  15. 2-year patient-related versus stent-related outcomes

    DEFF Research Database (Denmark)

    Jensen, Lisette Okkels; Thayssen, Per; Christiansen, Evald Høj;

    2012-01-01

    OBJECTIVES: There are limited head-to-head randomized data on patient-related versus stent-related outcomes for everolimus-eluting stents (EES) and sirolimus-eluting stents (SES). BACKGROUND: In the SORT OUT IV (Scandinavian Organization for Randomized Trials With Clinical Outcome IV) trial, comp...

  16. Local drug-delivery balloon for proliferative occlusive in-stent restenosis after drug-eluting stent

    Institute of Scientific and Technical Information of China (English)

    Gianluca Rigatelli; Paolo Cardaioli; Fabio Dell'Avvocata; Massimo Giordan

    2011-01-01

    Drug-coated balloon has been developed as an alternative to drug-eluting stents for in-stent restenosis but the performance of drug infusion balloon in such setting has not been previously described. We present a case of particularly aggressive in-stent restenosis after drug eluting stent implantation treated with a new kind of drug infusion balloon developed in order to overcome the impossibility to inflate regular drug-coated balloon for several dilatation.

  17. Sirolimus-eluting stent fractures associated with aneurysm and very late stent thrombosis in the right coronary artery

    Institute of Scientific and Technical Information of China (English)

    LIU Xuebo; Gary S.Mintz; Stéphane G.Carlier; Martin B.Leon

    2007-01-01

      Although the occurrence of coronary stent fracture is rare,recent reports showed that stent fracture after sirolimus-eluting stent(SES)implantation may be associated with neointimal hyperplasia and restenosis.We report two cases of stent fracture that occurred late after elective SES implantation into the right coronary artery(RCA)that were related to the aneurysm,restenosis,thrombosis,and vessel occlusion.……

  18. Partial stent-in-stent placement of biliary metallic stents using a short double-balloon enteroscopy

    Institute of Scientific and Technical Information of China (English)

    Koichiro Tsutsumi; Hironari Kato; Takeshi Tomoda; Kazuyuki Matsumoto; Ichiro Sakakihara; Naoki Yamamoto; Yasuhiro Noma

    2012-01-01

    Endoscopic intervention is less invasive than percutaneous or surgical approaches and should be considered the primary drainage procedure in most cases with obstructive jaundice.Recently,therapeutic endoscopic retrograde cholangiopancreatography (ERCP) using double-balloon enteroscopy (DBE) has been shown to be feasible and effective,even in patients with surgically altered anatomies.On the other hand,endoscopic partial stent-in-stent (PSIS) placement of selfexpandable metallic stents (SEMSs) for malignant hilar biliary obstruction in conventional ERCP has also been shown to be feasible,safe and effective.We performed PSIS placement of SEMSs for malignant hilar biliary obstruction due to liver metastasis using a short DBE in a patient with Roux-en-Y anastomosis and achieved technical and clinical success.This procedure can result in quick relief from obstructive jaundice in a single session and with short-term hospitalization,even in patients with surgically altered anatomies.

  19. Shortening of Wallstent RP during carotid artery stenting requires appropriate stent placement.

    Science.gov (United States)

    Aikawa, Hiroshi; Nagata, Shun-ichi; Onizuka, Masanari; Tsutsumi, Masanori; Iko, Minoru; Kodama, Tomonobu; Nii, Kouhei; Matsubara, Shuko; Etou, Hosei; Go, Yoshinori; Kazekawa, Kiyoshi

    2008-06-01

    Changes in the location and length of the Wallstent RP during carotid artery stenting (CAS) were evaluated using intraoperative videos of 28 patients with carotid artery stenosis who underwent CAS with a 10/20 mm Wallstent RP to determine the appropriate stent placement. The stent was deployed after its midpoint was positioned over a virtual center line, the perpendicular line which crossed the most stenotic point of the lesion on the road mapping image. The length of the stenotic lesion, the changes in the locations of the distal and proximal ends of the stent, and the changes in stent length were examined. The distal end of the stent moved a maximum of 6.1 mm toward the proximal side to a point 19.9 mm from the virtual center line. The proximal end moved a maximum of 11.3 mm toward the distal side to a point 14.7 mm from the virtual center line. The stent length ranged from 37.7 to 44.5 mm (mean 41.2 mm). The 10/20 mm Wallstent RP placed by our technique covers the entire lesion with no less than 5.7 mm of margin over the segment distal to the lesion in patients with stenotic segments shorter than 29.4 mm.

  20. Stent treatment of symptomatic intracranial arterial stenosis

    Directory of Open Access Journals (Sweden)

    DONG Feng-ju

    2012-08-01

    Full Text Available Objective To investigate the safety, feasibility and efficacy of the Wingspan stent in treatment of symptomatic intracranial arterial stenosis. Methods Wingspan stenting was applied in 90 cases with symptomatic intracranial arterial stenosis. The surgical success rate and periprocedural neurological complications were observed. Digital subtraction angiography was performed at 6 months after stenting to detect the occurrence of restenosis. Results The technical success rate was 98.92% (92/93. Pre-treatment stenosis (83.42 ± 9.53% was improved to (21.82 ± 9.86% after stent placement. The difference was statistically significant (t = 3.280, P = 0.002. There were 5 patients (5.56% occurred major periprocedural neurological complications, 3 of them died within 30 days after the procedure. The restenosis rate at 6 months after operation was 19.10% (17/89. Conclusion Symptomatic intracranial arterial stenosis can be treated by Wingspan stenting with high technical success rate. The occurrence of complication is low and short-term efficacy is good. However, further study is needed to investigate long-term effect.

  1. Novel Use of an Orbital Atherectomy Device for In-Stent Restenosis: Lessons Learned

    Directory of Open Access Journals (Sweden)

    K. Shaikh

    2016-01-01

    Full Text Available We present a case of a 67-year-old man with stage III chronic kidney disease, uncontrolled diabetes mellitus, coronary artery disease, and high surgical risk who presented with two episodes of acute coronary syndrome attributed to in-stent restenosis (ISR associated with heavily calcified lesions. In this case, we were able to improve luminal patency with orbital atherectomy system (OAS; however, withdrawal of the device resulted in a device/stent interaction, causing failure of the device. Given limitations in current evidence and therapies, managing ISR can be a technical and cognitive challenge. Balloon expansion of the affected region often provides unsatisfactory results, possibly related to significant calcium burden. OAS could be an efficacious way of reestablishing luminal patency in ISR lesions, as these lesions are often heavily calcified.

  2. Clinical outcomes and prognosis of patients with stent fracture after successful drug-eluting stent implantation

    Energy Technology Data Exchange (ETDEWEB)

    Kim, In Soo [Cadiovascular center, Chonnam National University Hospital, Gwangju (Korea, Republic of); Han, Jae Bok; Jang, Seong Joo [Dept. of Radiology, Dongshin University, Naju (Korea, Republic of)

    2014-06-15

    Many studies have suggested that in the era of Drug Eluting Stents (DES) are one of the causes of In-Stent Restenosis (ISR) of Stent Fracture (SF). The present study sought to evaluate clinical characteristics of patients with stent fracture after successful DES implantation. The 4,701 patients were selected for analysis who underwent a follow-up coronary angiography irrespective of ischemic symptoms. The overall incidence of SF was 32 patients(male:female=19:13, Av. age 62.44±9.8 year, 0.68%). Fractures of Sirolimus-Eluting Stents (SES), Paclitaxel-Eluting Stents (PES), Biolimus A9-Eluting Stents (BES), Everolimus-Eluting Etents (EES), Endothelial Progenitor Cell Capture Stent (EPC) and Zotarolimus-Eluting Stents (ZES) are accounted for 19 (59.4%), 9 (28.1%), 2 (6.3%), 1 (3.1%), 1 (3.1%) and 0 (0%) respectively. SF developed in the left Anterior Dscending (LAD) artery in 16 patients (50%) and in complex(type B2, C) lesions in 25 patients (69.4%). Ten patients were treated with heterogenous DES, the rest being treated with either homogenous DES (3 patients), plain old balloon angioplasty (3 patients), or conservative medical treatment (17 patients). None of the patients with SF suffered from cardiac death during a follow-up period of 32.9±12.4 months. The overall rate of DES fracture over up to 3.7 years of follow-up was 0.68% with higher incidence in SES than in PES. SF frequently occurred in the LAD artery and in complex lesions. Of the patients with SF, coronary intervention was performed only when the binary restenosis lesion was significant. During the follow-up, patients with SF have continued on combination antiplatelet therapy. There is a very low rate of major adverse cardiac events(post-detection of SF), especially cardiac death associated with SF.

  3. Stent thrombosis, myocardial infarction, and death after drug-eluting and bare-metal stent coronary interventions

    DEFF Research Database (Denmark)

    Jensen, Lisette Okkels; Maeng, Michael; Kaltoft, Anne;

    2007-01-01

    OBJECTIVES: The aim of the study was to examine outcomes subsequent to implantation of drug-eluting stents (DES) and bare-metal stents (BMS). BACKGROUND: Use of DES might be associated with increased risk of stent thrombosis (ST), myocardial infarction (MI), and death. METHODS: From January 2002 ...

  4. Safety and efficacy of stent placement for treatment of intracranial aneurysms: a systematic review

    Institute of Scientific and Technical Information of China (English)

    YANG Peng-fei; HUANG Qing-hai; ZHAO Wen-yuan; HONG Bo; XU Yi; LIU Jian-min

    2012-01-01

    Objective To evaluate the safety and efficacy of stent placement for the treatment of complex intracranial aneurysms.Data sources We searched six databases,including Pubmed,Embase,SCI-expanded,the Cochrane Library,ISI Proceedings and ProQuest Dissertations & Theses for the relevant studies using multiple key words from December,1997 to February,2009.Study selection Thirty-three studies about stent placement for intracranial aneurysms were identified,which reported data from a total of 1069 patients with 1121 intracranial aneurysms.Data extraction We prepared a standardized data extraction form (DEF),which was used by two independent researchers to extract data from the included 33 studies.Results The overall initial complete occlusion rate was 52.5% (456/869,95% CI:49.2%-55.8%).The overall complication rate was 14.3% (162/1130,95% CI:12.3%-16.4%),of which 3.6% (38/1044,95% CI:2.5%-4.8%) were permanent.Clinical follow-up showed a dependence rate of 8.4% (39/465,95% CI:5.9%-10.9%).Angiographic follow-up showed an improvement rate of 24.3% (117/481,95% CI:20,5%-28.2%) and a recurrence rate of 12.9% (62/481,95% CI:9.9%-15.9%).Chi-squared tests were performed to compare the following subgroups:self-expandable vs.balloon-expandable stents,unruptured vs.acutely ruptured aneurysms,and with vs.without pre-medication.Statistical significance was reached in eight tests.Conclusions Intracranial stent is a safe and effective tool for embolizing complex intracranial aneurysms.Self-expandable stents are significantly easier and safer than balloon-expandable stents with respect to navigation and deployment through the tortuous cerebral vasculature.Patients with acutely ruptured aneurysms are more likely to be deoendent,but not more likely to suffer more procedure-related complications.

  5. Mechanisms and Patterns of Intravascular Ultrasound In-Stent Restenosis Among Bare Metal Stents and First- and Second-Generation Drug-Eluting Stents.

    Science.gov (United States)

    Goto, Kosaku; Zhao, Zhijing; Matsumura, Mitsuaki; Dohi, Tomotaka; Kobayashi, Nobuaki; Kirtane, Ajay J; Rabbani, LeRoy E; Collins, Michael B; Parikh, Manish A; Kodali, Susheel K; Leon, Martin B; Moses, Jeffrey W; Mintz, Gary S; Maehara, Akiko

    2015-11-01

    The most common causes of in-stent restenosis (ISR) are intimal hyperplasia and stent under expansion. The purpose of this study was to use intravascular ultrasound (IVUS) to compare the ISR mechanisms of bare metal stents (BMS), first-generation drug-eluting stents (DES), and second-generation DES. There were 298 ISR lesions including 52 BMS, 73 sirolimus-eluting stents, 52 paclitaxel-eluting stents, 16 zotarolimus-eluting stents, and 105 everolimus-eluting stent. Mean patient age was 66.6 ± 1.1 years, 74.2% were men, and 48.3% had diabetes mellitus. BMS restenosis presented later (70.0 ± 66.7 months) with more intimal hyperplasia compared with DES (BMS 58.6 ± 15.5%, first-generation DES 52.6 ± 20.9%, second-generation DES 48.2 ± 22.2%, p = 0.02). Although reference lumen areas were similar in BMS and first- and second-generation DES, restenotic DES were longer (BMS 21.8 ± 13.5 mm, first-generation DES 29.4 ± 16.1 mm, second-generation DES 32.1 ± 18.7 mm, p = 0.003), and stent areas were smaller (BMS 7.2 ± 2.4 mm(2), first-generation DES 6.1 ± 2.1 mm(2), second-generation DES 5.7 ± 2.0 mm(2), p Stent fracture was seen only in DES (first-generation DES 7 [5.0%], second-generation DES 8 [7.4%], p = 0.13). In conclusion, restenotic first- and second-generation DES were characterized by less neointimal hyperplasia, smaller stent areas, longer stent lengths, and more stent fractures than restenotic BMS.

  6. Clinical Coronary In-Stent Restenosis Follow-Up after Treatment and Analyses of Clinical Outcomes

    Directory of Open Access Journals (Sweden)

    Barbara Campos Abreu Marino

    2015-05-01

    Full Text Available Background: Clinical in-stent restenosis (CISR is the main limitation of coronary angioplasty with stent implantation. Objective: Describe the clinical and angiographic characteristics of CISR and the outcomes over a minimum follow-up of 12 months after its diagnosis and treatment. Methods: We analyzed in 110 consecutive patients with CISR the clinical presentation, angiographic characteristics, treatment and combined primary outcomes (cardiovascular death, nonfatal acute myocardial infarction [AMI] and combined secondary (unstable angina with hospitalization, target vessel revascularization and target lesion revascularization during a minimal follow-up of one year. Results: Mean age was 61 ± 11 years (68.2% males. Clinical presentations included acute coronary syndrome (ACS in 62.7% and proliferative ISR in 34.5%. CISR was treated with implantation of drug-eluting stents (DES in 36.4%, Bare Metal Stent (BMS in 23.6%, myocardial revascularization surgery in 18.2%, balloon angioplasty in 15.5% and clinical treatment in 6.4%. During a median follow-up of 19.7 months, the primary outcome occurred in 18 patients, including 6 (5.5% deaths and 13 (11.8% AMI events. Twenty-four patients presented a secondary outcome. Predictors of the primary outcome were CISR with DES (HR = 4.36 [1.44–12.85]; p = 0.009 and clinical treatment for CISR (HR = 10.66 [2.53–44.87]; p = 0.001. Treatment of CISR with BMS (HR = 4.08 [1.75–9.48]; p = 0.001 and clinical therapy (HR = 6.29 [1.35–29.38]; p = 0.019 emerged as predictors of a secondary outcome. Conclusion: Patients with CISR present in most cases with ACS and with a high frequency of adverse events during a medium-term follow-up.

  7. Clinical Coronary In-Stent Restenosis Follow-Up after Treatment and Analyses of Clinical Outcomes

    Science.gov (United States)

    Marino, Barbara Campos Abreu; Nascimento, Guilherme Abreu; Rabelo, Walter; Marino, Marcos Antônio; Marino, Roberto Luiz; Ribeiro, Antonio Luiz Pinho

    2015-01-01

    Background Clinical in-stent restenosis (CISR) is the main limitation of coronary angioplasty with stent implantation. Objective Describe the clinical and angiographic characteristics of CISR and the outcomes over a minimum follow-up of 12 months after its diagnosis and treatment. Methods We analyzed in 110 consecutive patients with CISR the clinical presentation, angiographic characteristics, treatment and combined primary outcomes (cardiovascular death, nonfatal acute myocardial infarction [AMI]) and combined secondary (unstable angina with hospitalization, target vessel revascularization and target lesion revascularization) during a minimal follow-up of one year. Results Mean age was 61 ± 11 years (68.2% males). Clinical presentations included acute coronary syndrome (ACS) in 62.7% and proliferative ISR in 34.5%. CISR was treated with implantation of drug-eluting stents (DES) in 36.4%, Bare Metal Stent (BMS) in 23.6%, myocardial revascularization surgery in 18.2%, balloon angioplasty in 15.5% and clinical treatment in 6.4%. During a median follow-up of 19.7 months, the primary outcome occurred in 18 patients, including 6 (5.5%) deaths and 13 (11.8%) AMI events. Twenty-four patients presented a secondary outcome. Predictors of the primary outcome were CISR with DES (HR = 4.36 [1.44–12.85]; p = 0.009) and clinical treatment for CISR (HR = 10.66 [2.53–44.87]; p = 0.001). Treatment of CISR with BMS (HR = 4.08 [1.75–9.48]; p = 0.001) and clinical therapy (HR = 6.29 [1.35–29.38]; p = 0.019) emerged as predictors of a secondary outcome. Conclusion Patients with CISR present in most cases with ACS and with a high frequency of adverse events during a medium-term follow-up. PMID:25651344

  8. Treatment Approaches to Urinary Stones Caused by Forgotten DJ Stents

    Directory of Open Access Journals (Sweden)

    Ergun Alma

    2015-03-01

    Full Text Available Ureteral DJ stents have been used widely for years in urology practice. With increased use, complications have been increased and forgotton stents have started to cause problems. The most common complications are early pain and irritative symptoms. Late complications are bacterial colonization and stone formation because of the biofilm covering the stents. Treatment for a forgotten stent varies on many factors, such as stent localization and stone formation. In this article, we aimed to discuss our clinic approach on two different cases in light to current literature. [Cukurova Med J 2015; 40(Suppl 1: 58-63

  9. Fast virtual stenting with deformable meshes: application to intracranial aneurysms.

    Science.gov (United States)

    Larrabide, Ignacio; Radaelli, Alessandro; Frangi, Alejandro

    2008-01-01

    Intracranial stents are medical devices that are becoming increasingly popular in the treatment of intracranial aneurysms. A methodology that predicts the released stent configuration prior to intervention has the potential to support the physician in the selection of the optimal approach for a specific patient. This paper proposes a fast virtual stenting technique based on constrained simplex deformable models that is able to virtually release stents in arbitrarily shaped vessel and aneurysm models. The technique effectively embeds the geometrical properties of the stent (cell design, strut size and shape and angles between struts) and achieves favorable execution times of the order of one minute.

  10. Remnant mass, spin, and recoil from spin aligned black-hole binaries

    CERN Document Server

    Healy, James; Zlochower, Yosef

    2014-01-01

    We perform a set of 36 nonprecessing black-hole binary simulations with spins either aligned or counteraligned with the orbital angular momentum in order to model the final mass, spin, and recoil of the merged black hole as a function of the individual black hole spin magnitudes and the mass ratio of the progenitors. We find that the maximum recoil for these configurations is $V_{max}=526\\pm23\\,km/s$, which occurs when the progenitor spins are maximal, the mass ratio is $q_{max}=m_1/m_2=0.623\\pm0.038$, the smaller black-hole spin is aligned with the orbital angular momentum, and the larger black-hole spin is counteraligned ($\\alpha_1=-\\alpha_2=1$). This maximum recoil is about $80\\,km/s$ larger than previous estimates, but most importantly, because the maximum occurs for smaller mass ratios, the probability for a merging binary to recoil faster than $400\\,km/s$ can be as large as $17\\%$, while the probability for recoils faster than $250\\, km/s$ can be as large as $45\\%$. We provide explicit phenomenological ...

  11. On the M\\"ossbauer effect and the rigid recoil question

    CERN Document Server

    Davidson, Mark

    2016-01-01

    Various theories for the M\\"ossbauer rigid-recoil effect, which enables a crystal to absorb momentum but not appreciable energy, are compared. These suggest that the recoil may not be instantaneous, and that the recoil time could be used to distinguish between them. An experiment is proposed to measure this time. The idea is to use a small sphere whose outer surface is coated with an electrically charged M\\"ossbauer-active element, and then to measure the amount of energy lost due to Bremmsstrahlung during the recoil of this sphere when a M\\"ossbauer event occurs. As the energy radiated is proportional to the square of the acceleration from Larmor's formula, the amount of energy so radiated varies inversely proportional to the recoil time, and proportional to the charge squared. Although this energy is quite small, it can in principle be measured with the extreme sensitivity available in M\\"ossbauer experiments. It is found that the most information would be gained with more long-lived isomers such as Rhodium...

  12. Drug-eluting or bare-metal stents for large coronary vessel stenting? The BASKET-PROVE (PROspective Validation Examination) trial: Study protocol and design

    DEFF Research Database (Denmark)

    Pfisterer, M.; Bertel, O.; Bonetti, P.O.;

    2008-01-01

    Background Based on a subgroup analysis of 18-month BAsel Stent Kosten Effektivitats Trial (BASKET) outcome data, we hypothesized that very late (>12 months) stent thrombosis occurs predominantly after drug-eluting stent implantation in large native coronary vessel stenting. Methods To prove...... stent use in patients with large native vessel stenting. The 2-year death/myocardial infarction-as well as target vessel revascularization-and bleeding rates in these patients with a first-versus second-generation drug-eluting stent should demonstrate the benefit or harm of these stents compared...

  13. Brachial access technique for aortoiliac stenting revisited

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    We report a modified technique to perform iliac artery stenting through the brachial artery access. A 6F Brite tip sheath (Cordis, Jonhson & Jonhson Medical, Miami Lakes, FL, USA) is inserted into either brachial artery and a standard 4F Judkins Right diagnostic catheter was inserted over a 260 cm 0.038" Terumo Stiff wire (Terumo Corp, Tokyo, Japan) through the sheath. The catheter is navigated down to the aortic bifurcation, and after selecting the common iliac artery ostium, the wire is navigated through the lesion and advanced to the ipsilateral superficial femoral arteries. The catheter should be then moved forward over the wires beyond the lesion and the Terumo guidewire is replaced by two 0.038" 260 cm Supracor wires (Boston Scientific Corporation, San Jose, CA, USA). In order to facilitate advancement of the stent without risk of dislodgement as well as to check the position with low contrast dose injection, a 6 F (or 7F if large stent is selected) 90cm Shuttle Flexor introducer long sheath (Cook Group, Bloomington, IN, USA) should be advanced over the Supracor wire until it reaches the common iliac artery ostium. A road-map technique can be used to check the ostium position in order to properly deploy the selected stent. This technique promises to be safe and effective offering more support than guiding catheter technique; moreover it reduces the stress on the arterial vessel at the subclavian site and enables a stiff balloon or stent catheter to be advanced even through a very elongated and calcified aorta without the risk of stent dislodgement.

  14. Recent developments in drug-eluting coronary stents.

    Science.gov (United States)

    Yildiz, Mustafa; Yildiz, Banu Sahin; Gursoy, Mustafa Ozan; Akin, Ibrahim

    2014-01-01

    The interventional treatment of coronary artery disease was introduced in 1970`s by Andreas Grüntzig. The initial treatment strategy with plain old balloon angioplasty (POBA) was associated with high restenosis rates. The introduction of coronary stents, especially drug-eluting stents (DES) in 2002 has improved the results by lowering the rate of in-stent restenosis from 20-40% in the era of bare-metal stent (BMS) to 6-8%. However, in 2006 with the observation of late stent thrombosis the reputations of DES have decreased. However, improvements in stent design especially antiproliferative agents, polymeric agents as well as stent platforms improved newer generation DES. In controlled trials as well as registries the use of second-generation DES as compared to bare-metal stents (BMS) was associated with better clinical and angiographic results. A further development of these stents with use of biodegradable polymers, polymer-free stents, and biodegradable stents on the basis of poly L-lactide (PLLA) or magnesium resulted in third-generation DES and has been evaluated in preclinical and first clinical trials. However, to date, there is a lack of data comparing these third-generation DES with first- and second-generatrion DES in a large scale.

  15. Fast Virtual Stenting with Active Contour Models in Intracranical Aneurysm.

    Science.gov (United States)

    Zhong, Jingru; Long, Yunling; Yan, Huagang; Meng, Qianqian; Zhao, Jing; Zhang, Ying; Yang, Xinjian; Li, Haiyun

    2016-02-15

    Intracranial stents are becoming increasingly a useful option in the treatment of intracranial aneurysms (IAs). Image simulation of the releasing stent configuration together with computational fluid dynamics (CFD) simulation prior to intervention will help surgeons optimize intervention scheme. This paper proposed a fast virtual stenting of IAs based on active contour model (ACM) which was able to virtually release stents within any patient-specific shaped vessel and aneurysm models built on real medical image data. In this method, an initial stent mesh was generated along the centerline of the parent artery without the need for registration between the stent contour and the vessel. Additionally, the diameter of the initial stent volumetric mesh was set to the maximum inscribed sphere diameter of the parent artery to improve the stenting accuracy and save computational cost. At last, a novel criterion for terminating virtual stent expanding that was based on the collision detection of the axis aligned bounding boxes was applied, making the stent expansion free of edge effect. The experiment results of the virtual stenting and the corresponding CFD simulations exhibited the efficacy and accuracy of the ACM based method, which are valuable to intervention scheme selection and therapy plan confirmation.

  16. Cerrobend shielding stents for buccal carcinoma patients

    Directory of Open Access Journals (Sweden)

    Karma Yangchen

    2016-01-01

    Full Text Available Buccal carcinoma is one of the most common oral malignant neoplasms, especially in the South Asian region. Radiotherapy, which plays a significant role in the treatment of this carcinoma, has severe adverse effects. Different types of prosthesis may be constructed to protect healthy tissues from the adverse effects of treatment and concentrate radiation in the region of the tumor mass. However, the technique for fabrication of shielding stent with Lipowitz's alloy (cerrobend/Wood's alloy has not been well documented. This article describes detailed technique for fabrication of such a stent for unilateral buccal carcinoma patients to spare the unaffected oral cavity from potential harmful effects associated with radiotherapy.

  17. Carotid artery stenting versus no stenting assisting thrombectomy for acute ischaemic stroke

    DEFF Research Database (Denmark)

    Steglich-Arnholm, Henrik; Holtmannspötter, Markus; Gluud, Christian;

    2016-01-01

    , company homepages, reference lists, conference proceedings, and the Science Citation Index cited reference search index will be conducted. Manufacturers of relevant interventional equipment, authors, colleagues, and researchers active in the field will be contacted. No language restrictions...

  18. Spontaneous Solitaire™ AB Thrombectomy Stent Detachment During Stroke Treatment

    Energy Technology Data Exchange (ETDEWEB)

    Akpinar, Suha, E-mail: akpinarsuha@hotmail.com; Yilmaz, Guliz, E-mail: glz.yilmaz@hotmail.com [Near East University Hospital, Department of Radiology, Faculty of Medicine (Turkey)

    2015-04-15

    Spontaneous Solitaire™ stent retriever detachment is a rarely defined entity seen during stroke treatment, which can result in a disastrous clinical outcome if it cannot be solved within a critical stroke treatment time window. Two solutions to this problem are presented in the literature. The first is to leave the stent in place and apply angioplasty to the detached stent, while the second involves surgically removing the stent from the location at which it detached. Here, we present a case of inadvertent stent detachment during stroke treatment for a middle cerebral artery M1 occlusion resulting in progressive thrombosis. The detached stent was removed endovascularly by another Solitaire stent, resulting in the recanalization of the occluded middle cerebral artery.

  19. Transanal stent in anterior resection does not prevent anastomotic leakage

    DEFF Research Database (Denmark)

    Bülow, Steffen; Bulut, O; Christensen, Ib Jarle;

    2006-01-01

    OBJECTIVE: A defunctioning transanal stent may theoretically reduce the leakage rate after anterior rectal resection. We present a randomized open study with the aim of comparing the leakage rate after anterior resection with a loop ileostomy, a transanal stent, both or neither. PATIENTS...... completion of the operation the patients were randomized in two groups with and without a transanal stent. RESULTS: A clinically significant leakage was diagnosed in 25 patients (13%). No significant difference was found 17 of 98 patients with a stent and 8 of 96 without (P = 0.09), or in 9 of 44 ileostomy...... patients with a stent and in 3 of 45 without (P = 0.07). Several leaks over a short time led to an interim analysis after inclusion of 194 of 448 planned patients. The analysis showed no significant protective effect of the stent, and more leakages in the stent group, although not statistically significant...

  20. Experimental Study and Design of Balloon expandable Endovascular Stent Expansion

    Institute of Scientific and Technical Information of China (English)

    WANG Yue-xuan; YI Hong; NI Zhong-hua

    2005-01-01

    The application background and experimental research overview of medical endovascular stent are presented. Based on the analytical comparison of the current research achievements, the life cycle of medical endovascular stent is pointed out and the characteristics of stent expansion in the life cycle are emphasized on.The experimental scheme of in vitro stent expansion based on the machine vision technology in LabVIEW is presented. The selection and usage of the chosen component devices and design of measurement program for experiment are expatiated. A special drug-loading stent was expanded on the assembled platform of selected equipments and experimental results were analyzed. The experimental scheme presented in the paper provides powerful experimental support for the optimization of stent design and computer simulation of stent expansion by the finite element analysis.

  1. Simulation of stent deployment in a realistic human coronary artery

    Directory of Open Access Journals (Sweden)

    van der Steen Anton FW

    2008-08-01

    Full Text Available Abstract Background The process of restenosis after a stenting procedure is related to local biomechanical environment. Arterial wall stresses caused by the interaction of the stent with the vascular wall and possibly stress induced stent strut fracture are two important parameters. The knowledge of these parameters after stent deployment in a patient derived 3D reconstruction of a diseased coronary artery might give insights in the understanding of the process of restenosis. Methods 3D reconstruction of a mildly stenosed coronary artery was carried out based on a combination of biplane angiography and intravascular ultrasound. Finite element method computations were performed to simulate the deployment of a stent inside the reconstructed coronary artery model at inflation pressure of 1.0 MPa. Strut thickness of the stent was varied to investigate stresses in the stent and the vessel wall. Results Deformed configurations, pressure-lumen area relationship and stress distribution in the arterial wall and stent struts were studied. The simulations show how the stent pushes the arterial wall towards the outside allowing the expansion of the occluded artery. Higher stresses in the arterial wall are present behind the stent struts and in regions where the arterial wall was thin. Values of 200 MPa for the peak stresses in the stent strut were detected near the connecting parts between the stent struts, and they were only just below the fatigue stress. Decreasing strut thickness might reduce arterial damage without increasing stresses in the struts significantly. Conclusion The method presented in this paper can be used to predict stresses in the stent struts and the vessel wall, and thus evaluate whether a specific stent design is optimal for a specific patient.

  2. Effect of Shuxinyin (舒心饮) on In-Stent Restenosis after Coronary Artery Stenting

    Institute of Scientific and Technical Information of China (English)

    王显; 林钟香; 葛均波; 刘旭; 何燕; 张振贤; 沈琳

    2002-01-01

    Objective: To evaluate the effect of anti-platelet regimens and it's combination with Shuxinyin (SXY, 舒心饮,) on in-stent restenosis after stent implantation. Methods: Forty-four patients with successful stent implantation in a coronary artery were randomly assigned to the treated group (n=20) and the control group (n=24). The treated group received: SXY and anti-platelet therapy. The control group were treated with anti-platelet regimens only. Platelet activation was assessed before and immediately after the stenting by flow cytometry, the expression of P-selectin (CD62P) and glycoprotein(GP) Ⅱb/Ⅲa receptor. It was reassessed on the 30th day after stenting. Plasma fibrinogen (Fg) and C-reaction protein (CRP) were measured by biuret and laser scattering turbidimetry respectively at the same time. Observation was made on the scoring of the symptoms of Qi deficiency syndrome, Qi-Yin deficiency syndrome and blood stasis syndrome in the two groups. Differences between groups were compared. Results: Compared with the control group, combination with SXY and anti-platelet therapy was remarkable in reducing plasma CRP (P<0.05), and also with the tendency to decrease plasma Fg, GPⅡb/Ⅲa and CD62P. It could also evidently decrease the scoring of Qi-Yin deficiency syndrome, Qi deficiency syndrome and blood stasis syndrome after stenting (P<0.05, 0.01, 0.01) respectively. Follow-up survey found 40% relapse of angina pectoris with 4 cases of in-stent restenosis proved by angiography in the treated group. But the relapse of angina pectoris in the control group was 67% with 2 cases of myocardial infarction (MI), 7 cases of in-stent restenosis proved by angiography and one death. Conclusions: Combination with SXY and anti-platelet regimens can prevent stent thrombosis and in-stent restenosis after stent implantation, and it seems superior to anti-platelet therapy only.

  3. Determination of energetic neutron spatial distribution using neutron induced nuclear recoil events

    CERN Document Server

    Hashemi-Nezhad, S R; Brandt, R; Westmeier, W; Odoj, R; Krivopustov, M I; Kulakov, B A; Sosnin, A N

    2002-01-01

    Neutron induced nuclear recoils were used to determine the spatial distribution of the weakly moderated spallation neutrons produced in the interaction of 1 GeV protons with lead and uranium-lead targets. CR39 plastic track detectors were used to record neutron-induced recoil tracks. The track density measurements were carried out using a fully automated optical microscope. The experimental results were compared with Monte Carlo simulations using MCNPX-2.1.5 code and an extension code that was written for this purpose. A good agreement was found between the experiment and calculations for normalised results. Applicability of the MCNPX-2.1.5 code for absolute recoil track density determination is discussed.

  4. Observation of the 'head-tail' effect in nuclear recoils of low-energy neutrons

    CERN Document Server

    Dujmic, D; Lewandowska, M; Ahlen, S; Fisher, P; Kaboth, A; Kohse, G; Lanza, R; Monroe, J; Roccaro, A; Sciolla, G; Skvorodnev, N; Vanderspek, R; Wellenstein, H; Yamamoto, R

    2008-01-01

    The current experimental techniques may be inadequate to provide unambiguous positive signals as the limits on direct searches for dark matter improve. Thus, convincing evidence for dark matter particles may be possible only by detecting the direction of the incoming particles in the presence of background. We present in this article an experimental method to determine the direction and sense ('head-tail') of dark matter wind by measuring the direction of the elastic nuclear recoils in the scattering of dark matter particles with the detector material. We measure the direction and sense of the nuclear recoils created by the scattering of low-energy neutrons with CF4 in a low-pressure time-projection chamber as a demonstration. The decreasing stopping power along the recoil trajectory allows us to detect the sense and direction of the incoming neutrons, and proves that the 'head-tail' effect can be measured.

  5. Decay study of 20Na and its beta-delayed 16O recoiling

    Institute of Scientific and Technical Information of China (English)

    黄文学; 徐晓冀; 马瑞昌; 胡志强; 郭俊盛; 郭应祥; 刘洪业; 徐连联

    1997-01-01

    The decay of 20Na of astrophysical reactions has been studied deeply via 20Ne(p, n)20Na reaction. A new β-delayed α decay with α energy of 5 896 ± 6 keV and relative intensity of 0. 002 4 ± 0. 000 3 was discovered. At the same time the 16O recoiling in β+-delayed α decay of 20Na was observed in experiment for the first time. From these, it is inferred that a β-delayed low energy α decay of 20Na with energy of-780 keV and relative intensity of -1.4 was mixed in 16O recoiling. In 16O recoiling and the low energy α decay, the energy loss for low energy charged particles through matter was discussed in detail. At last, two methods for discriminating the β-delayed low energy α decay of 20Na were proposed.

  6. Searching for universal behaviour in superheated droplet detector with effective recoil nuclei

    Indian Academy of Sciences (India)

    Mala Das; Susnata Seth

    2013-06-01

    Energy calibration of superheated droplet detector is discussed in terms of the effective recoil nucleus threshold energy and the reduced superheat. This provides a universal energy calibration curve valid for different liquids used in this type of detector. Two widely used liquids, R114 and C4F10, one for neutron detection and the other for weakly interacting massive particles (WIMPs) dark matter search experiment, have been compared. Liquid having recoil nuclei with larger values of linear energy transfer (LET) provides better neutron- discrimination. Gamma () response of C4F10 has also been studied and the results are discussed. Behaviour of nucleation parameter with the effective recoil nucleus threshold energy and the reduced superheat have been explored.

  7. Dynamical simulations of radiation damage induced by 10 keV energetic recoils in UO 2

    Science.gov (United States)

    Tian, X. F.; Gao, T.; Long, Chongsheng; Li, JiuKai; Jiang, Gang; Xiao, Hongxing

    2011-08-01

    We have performed classical molecular dynamics simulations to simulate the primary damage state induced by 10 keV energetic recoils in UO 2. The numbers versus time and the distance distributions for the displaced uranium and oxygen atoms were investigated with the energetic recoils accelerated along four different directions. The simulations suggest that the direction of the primary knock-on atom (PKA) has no effect on the final primary damage state. In addition, it was found that atomic displacement events consisted of replacement collision sequences in addition to the production of Frenkel pairs. The spatial distribution of defects introduced by 10 keV collision cascades was also presented and the results were similar to that of energetic recoils with lower energy.

  8. First measurement of nuclear recoil head-tail sense in a fiducialised WIMP dark matter detector

    CERN Document Server

    Battat, J B R; Ezeribe, A C; Gauvreau, J -L; Harton, J L; Lafler, R; Lee, E R; Loomba, D; Lumnah, A; Miller, E H; Mouton, F; Murphy, A StJ; Paling, S M; Phan, N S; Robinson, M; Sadler, S W; Scarff, A; Schuckman, F G; Snowden-Ifft, D P; Spooner, N J C

    2016-01-01

    Recent computational results suggest that directional dark matter detectors have potential to probe for WIMP dark matter particles below the neutrino floor. The DRIFT-IId detector used in this work is a leading directional WIMP search time projection chamber detector. We report the first measurements of the detection of the directional nuclear recoils in a fully fiducialised low-pressure time projection chamber. In this new operational mode, the distance between each event vertex and the readout plane is determined by the measurement of minority carriers produced by adding a small amount of oxygen to the nominal CS$_{2}$ + CF$_{4}$ target gas mixture. The CS$_2$ + CF$_4$ + O$_2$ mixture has been shown to enable background-free operation at current sensitivities. Sulfur, fluorine, and carbon recoils were generated using neutrons emitted from a $^{252}$Cf source positioned at different locations around the detector. Measurement of the relative energy loss along the recoil tracks allowed the track vector sense, ...

  9. On recoil energy dependent void swelling in pure copper: part 1, experimental results

    DEFF Research Database (Denmark)

    Singh, B.N.; Eldrup, M.; Horsewell, Andy

    2000-01-01

    , the void swelling should sensitively depend on the recoil energy since it affects strongly the intracascade clustering of SIAs and vacancies, particularly at lower recoil energies. In order to test the validity of this prediction directly by experiments, pure and annealed copper specimens were irradiated...... with 2.5 MeV electrons, 3 MeV protons and fission neutrons at about 520K. All three sets of irradiation experiments were carried out with a similar damage rate (of the order of 10-8 NRT dpa/s). Post-irradiation defect microstructures were investigated using electrical resistivity, transmission electron...... microscopy (TEM) and positron annihilation spectroscopy (PAS). The accumulation of defects in the form of planar clusters as well as voids is found to increase substantially with increasing recoil energy. This is in good accord with the predictions of the PBM....

  10. On recoil energy dependent void swelling in pure copper: Theoretical treatment

    DEFF Research Database (Denmark)

    Golubov, S.I.; Singh, Bachu Narain; Trinkaus, H.

    2000-01-01

    the effect of recoil energy on damage accumulation. Recently, dedicated irradiation experiments using 2.5 MeV electrons, 3.0 MeV protons and fission neutrons have been carried out to determine the effect of recoilenergy on the damage accumulation behaviour in pure copper and the results have been reported......Over the years, an enormous amount of experimental results have been reported on damage accumulation (e.g. void swelling) in metals and alloys irradiated under vastly different recoil energy conditions. Unfortunately, however, very little is known eitherexperimentally or theoretically about...... in Part I of this paper (Singh, Eldrup, Horsewell, Ehrhart and Dworschak 2000). The present paper attempts to provide a theoretical framework within which theeffect of recoil energy on damage accumulation behaviour can be understood. The damage accumulation under Frenkel pair production (e.g. 2.5 Me...

  11. Heavy ion recoil spectrometry of Si{sub x}Ge{sub 1-x} thin films

    Energy Technology Data Exchange (ETDEWEB)

    Walker, S.R.; Johnston, P.N.; Bubb, I.F. [Royal Melbourne Inst. of Tech., VIC (Australia); Cohen, D.D.; Dytlewski, N. [Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW (Australia); Hult, M.; Whitlow, H.J. [Lund Institute of Technology, Solvegatan (Sweden). Department of Nuclear Physics; Zaring, C.; Oestling, M. [Royal Inst. of Tech., Stockholm (Sweden). Dept. of Solid State Electronics

    1993-12-31

    Mass and energy dispersive recoil spectrometry employing 77 MeV {sup 127}I ions from ANTARES (FN Tandem) facility at Lucas Heights has been used to examine the isotopic composition of samples of Si{sub x}Ge{sub 1-x} grown at the Australian National University by Electron Beam Evaporation (EBE). The recoiling target nuclei were analysed by a Time Of Flight and Energy (TOF-E) detector telescope composed of two timing pickoff detectors and a surface barrier (energy) detector. From the time of flight and energy, the ion mass can be determined and individual depth distributions for each element can be obtained. Recoil spectrometry has shown the presence of oxygen in the Si{sub x}Ge{sub 1-x} layer and has enabled the separate determination of energy spectra for individual elements. 9 refs., 3 figs.

  12. Prospective, multi-center evaluation of a silicon carbide coated cobalt chromium bare metal stent for percutaneous coronary interventions: Two-year results of the ENERGY Registry

    Energy Technology Data Exchange (ETDEWEB)

    Erbel, Raimund, E-mail: erbel@uk-essen.de [Department of Cardiology, University of Duisburg-Essen, Essen (Germany); Eggebrecht, Holger [Cardioangiological Center Bethanien (CCB), Frankfurt (Germany); Roguin, Ariel [Department of Cardiology, Rambam Medical Center, Haifa (Israel); Schroeder, Erwin [Division of Cardiovascular Medicine, Cliniques Universitaires de Mont-Godinne, Yvoir (Belgium); Philipp, Sebastian [Department Internal Medicine/Cardiology, Elbe Klinikum Stade, Stade (Germany); Heitzer, Thomas [Department of Cardiology, Heart Center Dortmund, Dortmund (Germany); Schwacke, Harald [Department of Internal Medicine, Diakonissen-Stiftungs- Krankenhaus Speyer (Germany); Ayzenberg, Oded [The Heart Institute, Kaplan Medical Center, Rehovot (Israel); Serra, Antonio [Servicio de Cardiología, Hospital de la Santa Creu i Sant Pau, Barcelona, España (Spain); Delarche, Nicolas [Cardiology unit, Pau General Hospital, Pau (France); Luchner, Andreas [Department of Internal Medicine/Cardiology, Universitätsklinikum Regensburg (Germany); Slagboom, Ton [Department of Cardiology, Onze Lieve Vrouwe Gasthuis, Amsterdam (Netherlands)

    2014-11-15

    Background: Novel bare metal stents with improved stent design may become a viable alternative to drug-eluting stents in certain patient groups, particularly, when long-term dual antiplatelet therapy should be avoided. Purpose: The ENERGY registry aimed to assess the safety and benefits of a cobalt–chromium thin strut bare metal stent with a passive coating in a large series of patients under real-world conditions. Methods and materials: This prospective registry recruited 1016 patients with 1074 lesions in 48 centers from April to November 2010. The primary endpoint was the rate of major adverse cardiac events (MACEs), a composite of cardiac death, myocardial infarction and clinically driven target lesion revascularization. Results: More than half of the lesions (61.0%) were type A/B1 lesions, mean lesion length was 14.5 ± 6.5 mm and mean reference vessel diameter 3.2 ± 0.5 mm. MACE rates at 6, 12 and 24 months were 4.9%, 8.1% and 9.4%, target lesion revascularization rates 2.8%, 4.9% and 5.4% and definite stent thrombosis rates 0.5%, 0.6% and 0.6%. Subgroups showed significant differences in baseline and procedural characteristics which did not translate into significantly different clinical outcomes. Specifically, MACE rates at 24 months were 13.5% in diabetics, 8.6% in small stents and 9.6% in acute coronary syndrome patients. Conclusion: The population of ENERGY reflects real-world conditions with bare metal stents being mainly used in simple lesions. In this setting, percutaneous coronary intervention using a cobalt–chromium thin strut bare metal stent with a passive coating showed very good results up to 24 months. (ClinicalTrials.gov:NCT01056120) Summary for annotated table of contents: The ENERGY international registry evaluated the safety and benefits of a cobalt–chromium thin strut bare metal stent with passive coating in 1016 patients under real-world conditions until 2 years. Results were encouraging with a low composite rate of cardiac death

  13. Local sustained delivery of acetylsalicylic acid via hybrid stent with biodegradable nanofibers reduces adhesion of blood cells and promotes reendothelialization of the denuded artery

    Directory of Open Access Journals (Sweden)

    Lee CH

    2014-01-01

    Full Text Available Cheng-Hung Lee,1,2 Yu-Huang Lin,3 Shang-Hung Chang,1 Chun-Der Tai,3 Shih-Jung Liu,2 Yen Chu,4 Chao-Jan Wang,5 Ming-Yi Hsu,5 Hung Chang,6 Gwo-Jyh Chang,7 Kuo-Chun Hung,1 Ming-Jer Hsieh,1 Fen-Chiung Lin,1 I-Chang Hsieh,1 Ming-Shien Wen,1 Yenlin Huang81Division of Cardiology, Department of Internal Medicine, Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Linkou, 2Department of Mechanical Engineering, 3Graduate Institute of Medical Mechatronics, Chang Gung University, 4Laboratory of Cardiovascular Physiology, Division of Thoracic and Cardiovascular Surgery, 5Department of Medical Imaging and Intervention, 6Hematology-Oncology Division, Department of Internal Medicine, Chang Gung Memorial Hospital, Linkou, 7Graduate Institute of Clinical Medicinal Sciences, Chang Gung University College of Medicine, Linkou, 8Department of Anatomical Pathology, Chang Gung Memorial Hospital, Linkou, Tao-Yuan, TaiwanAbstract: Incomplete endothelialization, blood cell adhesion to vascular stents, and inflammation of arteries can result in acute stent thromboses. The systemic administration of acetylsalicylic acid decreases endothelial dysfunction, potentially reducing thrombus, enhancing vasodilatation, and inhibiting the progression of atherosclerosis; but, this is weakened by upper gastrointestinal bleeding. This study proposes a hybrid stent with biodegradable nanofibers, for the local, sustained delivery of acetylsalicylic acid to injured artery walls. Biodegradable nanofibers are prepared by first dissolving poly(D,L-lactide-co-glycolide and acetylsalicylic acid in 1,1,1,3,3,3-hexafluoro-2-propanol. The solution is then electrospun into nanofibrous tubes, which are then mounted onto commercially available bare-metal stents. In vitro release rates of pharmaceuticals from nanofibers are characterized using an elution method, and a high-performance liquid chromatography assay. The experimental results suggest that biodegradable nanofibers

  14. Primary angioplasty and later elective multivessel stenting in a patient with dextrocardia: a case report and literature review.

    Science.gov (United States)

    Elbasheer, Elbagir; Habib, Abdelhakim; Salam, Adil

    2010-07-01

    Dextrocardia is a rare congenital anomaly with a prevalence of 1 in 10,000 births. The incidence of coronary artery disease in such patients is thought to be similar to that of the general public, however, patients are seldom seen during routine clinical practice and at the cardiac catheterization laboratory. Patients with this condition and acute myocardial ischemia may pose challenges at presentation, clinical and diagnostic findings and at cardiac catheterization. In this report, a male patient presenting with acute inferior myocardial infarction and three-vessel coronary artery disease was managed successfully with emergency primary angioplasty and later elective multivessel stenting. This is the first combined primary and later multivessel stenting to be reported in a single patient with dextrocardia and situs inversus. The clinical findings, details of the procedures and literature review will be discussed.

  15. Computational simulation of platelet interactions in the initiation of stent thrombosis due to stent malapposition

    Science.gov (United States)

    Chesnutt, Jennifer K W; Han, Hai-Chao

    2016-01-01

    Coronary stenting is one of the most commonly used approaches to open coronary arteries blocked due to atherosclerosis. Stent malapposition can induce thrombosis but the microscopic process is poorly understood. The objective of this study was to determine the platelet-level process by which different extents of stent malapposition affect the initiation of stent thrombosis. We utilized a discrete element model to computationally simulate the transport, adhesion, and activation of thousands of individual platelets and red blood cells during thrombus initiation in stented coronary arteries. Simulated arteries contained a malapposed stent with a specified gap distance (0, 10, 25, 50, or 200 μm) between the struts and endothelium. Platelet-level details of thrombus formation near the proximal-most strut were measured during the simulations. The relationship between gap distance and amount of thrombus in the artery varied depending on different conditions (e.g., amount of dysfunctional endothelium, shear-induced activation of platelets, and thrombogenicity of the strut). Without considering shear-induced platelet activation, the largest gap distance (200 μm) produced no recirculation and less thrombus than the smallest two gap distances (0 and 10 μm) that created recirculation downstream of the strut. However, with the occurrence of shear-induced platelet activation, the largest gap distance produced more thrombus than the two smallest gap distances, but less thrombus than an intermediate gap distance (25 μm). A large gap distance was not necessarily the most thrombogenic, in contrast to implications of some computational fluid dynamics studies. The severity of stent malapposition affected initial stent thrombosis differently depending on various factors related to fluid recirculation, platelet trajectories, shear stress, and endothelial condition. PMID:26790093

  16. Computational simulation of platelet interactions in the initiation of stent thrombosis due to stent malapposition

    Science.gov (United States)

    Chesnutt, Jennifer K. W.; Han, Hai-Chao

    2016-02-01

    Coronary stenting is one of the most commonly used approaches to open coronary arteries blocked due to atherosclerosis. Stent malapposition can induce thrombosis but the microscopic process is poorly understood. The objective of this study was to determine the platelet-level process by which different extents of stent malapposition affect the initiation of stent thrombosis. We utilized a discrete element model to computationally simulate the transport, adhesion, and activation of thousands of individual platelets and red blood cells during thrombus initiation in stented coronary arteries. Simulated arteries contained a malapposed stent with a specified gap distance (0, 10, 25, 50, or 200 μm) between the struts and endothelium. Platelet-level details of thrombus formation near the proximal-most strut were measured during the simulations. The relationship between gap distance and amount of thrombus in the artery varied depending on different conditions (e.g., amount of dysfunctional endothelium, shear-induced activation of platelets, and thrombogenicity of the strut). Without considering shear-induced platelet activation, the largest gap distance (200 μm) produced no recirculation and less thrombus than the smallest two gap distances (0 and 10 μm) that created recirculation downstream of the strut. However, with the occurrence of shear-induced platelet activation, the largest gap distance produced more thrombus than the two smallest gap distances, but less thrombus than an intermediate gap distance (25 μm). A large gap distance was not necessarily the most thrombogenic, in contrast to implications of some computational fluid dynamics studies. The severity of stent malapposition affected initial stent thrombosis differently depending on various factors related to fluid recirculation, platelet trajectories, shear stress, and endothelial condition.

  17. Morphologic characteristics of late stent malapposition after drug-eluting stents implantation by optical coherence tomography follow-up

    Institute of Scientific and Technical Information of China (English)

    HOU Jing-bo; LIU Hui-min; MA Li-jia; YANG Shuang; MENG Ling-bo; HAN Zhi-gang; ZHANG Shuo; YU Bo

    2010-01-01

    Background Late stent malapposition was frequently observed after DES implantation, which has been associated with the occurrence of late stent thrombosis due to poor neointimal coverage. This study was designed to evaluate the frequency of late stent malapposition at least 1 year after different DESs implantation by optical coherence tomography (OCT). Methods Angiographic and OCT examinations were given to 68 patients who had received total 126 various DESs implantation for at least 1 year to detect late stent malapposition. Malapposed strut distance (MSD), malapposed strut area (MSA), reference lumen area (RLA) and reference stent area (RSA) were checked with off-line OCT analysis. Results Totally 26 Cypher Select stents, 15 Taxus Liberte stents, 51 Partner stents and 34 Firebird I stents were examined. Among 68 patients who underwent DES implantation, 7 patients (10.3%) had late malapposition. Average RSA, MSA and MSD were (7.9±2.8)mm~2,(2.0±1.6)mm~2 and (590±270)μm respectively.According to the MSA/RSA ratio,4 patients had slight malapposition,2 patients had moderate malapposition and 1 patient had severe malapposition.Conclusions Late stent malapposition is detected frequently after implantation of DES,but if this predisposes to late stent thrombosis and requires any specific therapy needs to be further elucidated.

  18. A novel balloon assisted two-stents telescoping technique for repositioning an embolized stent in the pulmonary conduit.

    Science.gov (United States)

    Kobayashi, Daisuke; Gowda, Srinath T; Forbes, Thomas J

    2014-08-01

    A 9-year-old male, with history of pulmonary atresia and ventricular septal defect, status post complete repair with a 16 mm pulmonary homograft in the right ventricular outflow tract (RVOT) underwent 3110 Palmaz stent placement for conduit stenosis. Following deployment the stent embolized proximally into the right ventricle (RV). We undertook the choice of repositioning the embolized stent into the conduit with a transcatheter approach. Using a second venous access, the embolized stent was carefully maneuvered into the proximal part of conduit with an inflated Tyshak balloon catheter. A second Palmaz 4010 stent was deployed in the distal conduit telescoping through the embolized stent. The Tyshak balloon catheter was kept inflated in the RV to stabilize the embolized stent in the proximal conduit until it was successfully latched up against the conduit with the deployment of the overlapping second stent. One year later, he underwent Melody valve implantation in the pre-stented conduit relieving conduit insufficiency. This novel balloon assisted two-stents telescoping technique is a feasible transcatheter option to secure an embolized stent from the RV to the RVOT.

  19. Inflammation and in-stent restenosis: the role of serum markers and stent characteristics in carotid artery stenting.

    Directory of Open Access Journals (Sweden)

    Katrin Wasser

    Full Text Available BACKGROUND: Carotid angioplasty and stenting (CAS may currently be recommended especially in younger patients with a high-grade carotid artery stenosis. However, evidence is accumulating that in-stent restenosis (ISR could be an important factor endangering the long-term efficacy of CAS. The aim of this study was to investigate the influence of inflammatory serum markers and procedure-related factors on ISR as diagnosed with duplex sonography. METHODS: We analyzed 210 CAS procedures in 194 patients which were done at a single university hospital between May 2003 and June 2010. Periprocedural C-reactive protein (CRP and leukocyte count as well as stent design and geometry, and other periprocedural factors were analyzed with respect to the occurrence of an ISR as diagnosed with serial carotid duplex ultrasound investigations during clinical long-term follow-up. RESULTS: Over a median of 33.4 months follow-up (IQR: 14.9-53.7 of 210 procedures (mean age of 67.9±9.7 years, 71.9% male, 71.0% symptomatic an ISR of ≥70% was detected in 5.7% after a median of 8.6 months (IQR: 3.4-17.3. After multiple regression analysis, leukocyte count after CAS-intervention (odds ratio (OR: 1.31, 95% confidence interval (CI: 1.02-1.69; p = 0.036, as well as stent length and width were associated with the development of an ISR during follow-up (OR: 1.25, 95% CI: 1.05-1.65, p = 0.022 and OR: 0.28, 95% CI: 0.09-0.84, p = 0.010. CONCLUSIONS: The majority of ISR during long-term follow-up after CAS occur within the first year. ISR is associated with periinterventional inflammation markers and influenced by certain stent characteristics such as stent length and width. Our findings support the assumption that stent geometry leading to vessel injury as well as periprocedural inflammation during CAS plays a pivotal role in the development of carotid artery ISR.

  20. Endovascular repair of arterial iliac vessel wall lesions with a self-expandable nitinol stent graft system.

    Directory of Open Access Journals (Sweden)

    Birger Mensel

    Full Text Available OBJECTIVE: To assess the therapeutic outcome after endovascular repair of iliac arterial lesions (IALs using a self-expandable Nitinol stent graft system. METHODS: Between July 2006 and March 2013, 16 patients (13 males, mean age: 68 years with a self-expandable Nitinol stent graft. A total of 19 lesions were treated: nine true aneurysms, two anastomotic aneurysms, two dissections, one arteriovenous fistula, two type 1B endoleaks after endovascular aneurysm repair, one pseudoaneurysm, and two perforations after angioplasty. Pre-, intra-, and postinterventional imaging studies and the medical records were analyzed for technical and clinical success and postinterventional complications. RESULTS: The primary technical and clinical success rate was 81.3% (13/16 patients and 75.0% (12/16, respectively. Two patients had technical failure due to persistent type 1A endoleak and another patient due to acute stent graft thrombosis. One patient showed severe stent graft kinking on the first postinterventional day. In two patients, a second intervention was performed. The secondary technical and clinical success rate was 87.5% (14/16 and 93.8% (15/16. The minor complication rate was 6.3% (patient with painful hematoma at the access site. The major complication rate was 6.3% (patient with ipsilateral deep vein thrombosis. During median follow-up of 22.4 months, an infection of the aneurysm sac in one patient and a stent graft thrombosis in another patient were observed. CONCLUSION: Endovascular repair of various IALs with a self-expandable Nitinol stent graft is safe and effective.

  1. On recoil energy dependent void swelling in pure copper: Theoretical treatment

    Energy Technology Data Exchange (ETDEWEB)

    Golubov, S.I. [Institute of Physics and Power Engineering, Obninsk (Russian Federation); Singh, B.N.; Trinkaus, H. [Institute fuer Festkoerperforschung, Forschungszentrum Juelich (Germany)

    2000-06-15

    Over the years, an enormous amount of experimental results have been reported on damage accumulation (e.g. void swelling) in metals and alloys irradiated under vastly different recoil energy conditions. Unfortunately, however, very little is known either experimentally or theoretically about the effect of recoil energy on damage accumulation. Recently, dedicated irradiation experiments using 2.5 MeV electrons, 3.0 MeV protons and fission neutrons have been carried out to determine the effect of recoil energy on the damage accumulation behaviour in pure copper and the results have been reported in Part I of this paper (Singh, Eldrup, Horsewell, Ehrhart and Dworschak 2000). The present paper attempts to provide a theoretical framework within which the effect of recoil energy on damage accumulation behaviour can be understood. The damage accumulation under Frenkel pair production (e.g. 2.5 MeV electron) has been treated in terms of the standard rate theory (SRT) model whereas the evolution of the defect microstructure under cascade damage conditions (e.g. 3.0 MeV protons and fission neutrons) has been calculated within the framework of the production bias model (PBM). Theoretical results, in agreement with experimental results, show that the damage accumulation behaviour is very sensitive to recoil energy and under cascade damage conditions can be treated only within the framework of the PBM. The intracascade clustering of self-interstitial atoms (SIAs) and the properties of SIA clusters such as one-dimensional diffusional transport and thermal stability are found to be the main reasons for the recoil energy dependent vacancy supersaturation. The vacancy supersaturation is the main driving force for the void nucleation and void swelling. In the case of Frenkel pair production, the experimental results are found to be consistent with the SRT model with a dislocation bias value of 2 %. (au)

  2. Experiment Study of The Preventive Effects of Valsartan Eluting Stent on In- stent Restenosis

    Institute of Scientific and Technical Information of China (English)

    陈津; 陈纪言; 周颖玲; 李光; 罗建方; 余丹青; 张励庭; 黄文晖

    2003-01-01

    Objectives Background -Neointima hyperplasia and arterial re modeling are themain mechanisms of restenosis after percutaneoustransluminal coronary angioplasty. The successful useof coronary stents neutralizes the ac ute elastic recoiland improves the remodeling mode with reducingrestenosis rate by 10 % . But the in - stent neointimahyperplasia becomes more severe. This study aims toset up model of in - stent restenosis in vivo, and to e-valuate the preventive role of implantation of valsartaneluting stent for restenosis. Methods and ResultsTwenty -two male New Zealand white rabbits were di-vided into control group and valsartan group. In-travascular ultrasonic (IVUS) results showed the in-trastent neointimal areas of the control group werelarger than those of the valsartan group ( P < 0.01 ) .The minimal lumen area of control group was smallerthan that of the valsartan group ( P < 0.01). Angiog-raphy results showed the normal lumen diameters weresimilar between two groups ( P> 0.05) . The lumenstenosis rates compared with the normal diameters ofthe valsartan group were significantly improved overthat of the control group ( P < 0. 05) . It was compa-rable to the IVUS analysis. There were no cases of a-neurysm or thrombosis. Conclusions Valsartan e-luting stents produced a significant inhibition ofneointimal hyperplasia and luminal encroachment inrabbits without obviously producing any serious side -effects. These results demonstrate the potential thera-peutic benefit of valsartan eluting stents in the pre-vention and treatment of human coronary restenosis.

  3. Infrarenal abdominal aortic aneurysm. Endovascular repair with stent grafts; Infrarenales Bauchaortenaneurysma. Endovaskulaere Stent-Graft-Therapie

    Energy Technology Data Exchange (ETDEWEB)

    Wagner, M.; Voshage, G.; Landwehr, P. [Klinik fuer Diagnostische und Interventionelle Radiologie, Gefaesszentrum Hannover, Diakoniekrankenhaus Henriettenstiftung gGmbH, Hannover (Germany); Busch, T. [Klinik fuer Gefaesschirurgie, Gefaesszentrum Hannover, Diakoniekrankenhaus Henriettenstiftung gGmbH, Hannover (Germany)

    2008-09-15

    As an alternative to surgery, endovascular therapy with stent grafts has become the second main treatment option for infrarenal abdominal aortic aneurysms. Unlike surgery, endovascular treatment with stent grafts is also applicable in patients unfit for open repair. Despite current improvements in endovascular repair devices, significant anatomic barriers still exclude this technique for a large number of patients. Computed tomography, magnetic resonance imaging, and ultrasound are essential for diagnostics, preintervention planning, and postintervention follow-up of abdominal aneurysms treated with stent grafts. This review covers etiology, pathology, and diagnostic aspects. Materials and methods for endovascular treatment of abdominal aortic aneurysms are presented in detail, and clinical results and complications are discussed. (orig.) [German] Die endovaskulaere Therapie des infrarenalen Bauchaortenaneurysmas hat sich als Alternative zur offenen chirurgischen Versorgung etabliert. Im Gegensatz zu Letzterer ist die Aneurysmatherapie mittels Stent-Grafts auch bei schwerkranken, nicht operationsfaehigen Patienten moeglich, wobei der Nutzen kontrovers diskutiert wird. Im Gegensatz zur klassischen transabdominellen Operation ist die Stent-Graft-Technik anatomischen Einschraenkungen unterworfen, die aber kuenftig aufgrund bereits abzusehender technischer Weiterentwicklungen eine geringere Rolle spielen werden. Die Diagnostik, die Entscheidung fuer eine endovaskulaere Therapie, die praeinterventionelle Planung und die Nachsorge erfordern den Einsatz bildgebender Verfahren, v. a. der Computer- und Magnetresonanztomographie sowie der Sonographie. Die fuer die endovaskulaere Aneurysmabehandlung relevanten Aspekte der Diagnostik werden dargestellt. Auf die Technik, die Materialien, die Ergebnisse und die Komplikationen der Stent-Graft-Behandlung wird ausfuehrlich eingegangen. (orig.)

  4. Finite nuclear size corrections to the recoil effect in hydrogenlike ions

    CERN Document Server

    Aleksandrov, I A; Glazov, D A; Shabaev, V M

    2014-01-01

    The finite nuclear size corrections to the relativistic recoil effect in H-like ions are calculated within the Breit approximation. The calculations are performed for the $1s$, $2s$, and $2p_{1/2}$ states in the range $Z =$ 1-110. The obtained results are compared with previous evaluations of this effect. It is found that for heavy ions the previously neglected corrections amount to about 20% of the total nuclear size contribution to the recoil effect calculated within the Breit approximation.

  5. A new recoil distance technique using low energy coulomb excitation in inverse kinematics

    Energy Technology Data Exchange (ETDEWEB)

    Rother, W., E-mail: wolfram.rother@googlemail.com [Institut fuer Kernphysik der Universitaet zu Koeln, Zuelpicher Str. 77, D-50937 Koeln (Germany); Dewald, A.; Pascovici, G.; Fransen, C.; Friessner, G.; Hackstein, M. [Institut fuer Kernphysik der Universitaet zu Koeln, Zuelpicher Str. 77, D-50937 Koeln (Germany); Ilie, G. [Wright Nuclear Structure Laboratory, Yale University, New Haven, CT 06520 (United States); National Institute of Physics and Nuclear Engineering, P.O. Box MG-6, Bucharest-Magurele (Romania); Iwasaki, H. [National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, MI 48824 (United States); Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824 (United States); Jolie, J. [Institut fuer Kernphysik der Universitaet zu Koeln, Zuelpicher Str. 77, D-50937 Koeln (Germany); Melon, B. [Dipartimento di Fisica, Universita di Firenze and INFN Sezione di Firenze, Sesto Fiorentino (Firenze) I-50019 (Italy); Petkov, P. [Institut fuer Kernphysik der Universitaet zu Koeln, Zuelpicher Str. 77, D-50937 Koeln (Germany); INRNE-BAS, Sofia (Bulgaria); Pfeiffer, M. [Institut fuer Kernphysik der Universitaet zu Koeln, Zuelpicher Str. 77, D-50937 Koeln (Germany); Pissulla, Th. [Institut fuer Kernphysik der Universitaet zu Koeln, Zuelpicher Str. 77, D-50937 Koeln (Germany); Bundesumweltministerium, Robert-Schuman-Platz 3, D - 53175 Bonn (Germany); Zell, K.-O. [Institut fuer Kernphysik der Universitaet zu Koeln, Zuelpicher Str. 77, D-50937 Koeln (Germany); Jakobsson, U.; Julin, R.; Jones, P.; Ketelhut, S.; Nieminen, P.; Peura, P. [Department of Physics, University of Jyvaeskylae, P.O. Box 35, FI-40014 (Finland); and others

    2011-10-21

    We report on the first experiment combining the Recoil Distance Doppler Shift technique and multistep Coulomb excitation in inverse kinematics at beam energies of 3-10 A MeV. The setup involves a standard plunger device equipped with a degrader foil instead of the normally used stopper foil. An array of particle detectors is positioned at forward angles to detect target-like recoil nuclei which are used as a trigger to discriminate against excitations in the degrader foil. The method has been successfully applied to measure lifetimes in {sup 128}Xe and is suited to be a useful tool for experiments with radioactive ion beams.

  6. Discrimination of nuclear and electronic recoil events using plasma effect in germanium detectors

    Science.gov (United States)

    Wei, W.-Z.; Liu, J.; Mei, D.-M.

    2016-07-01

    We report a new method of using the plasma time difference, which results from the plasma effect, between the nuclear and electronic recoil events in high-purity germanium detectors to distinguish these two types of events in the search for rare physics processes. The physics mechanism of the plasma effect is discussed in detail. A numerical model is developed to calculate the plasma time for nuclear and electronic recoils at various energies in germanium detectors. It can be shown that under certain conditions the plasma time difference is large enough to be observable. The experimental aspects in realizing such a discrimination in germanium detectors is discussed.

  7. Discrimination of nuclear and electronic recoil events using plasma effect in germanium detectors

    CERN Document Server

    Wei, W -Z; Mei, D -M

    2016-01-01

    We report a new method of using the plasma time difference, which results from the plasma effect, between the nuclear and electronic recoil events in high-purity germanium detectors to distinguish these two types of events in the search for rare physics processes. The physics mechanism of the plasma effect is discussed in detail. A numerical model is developed to calculate the plasma time for nuclear and electronic recoils at various energies in germanium detectors. It can be shown that under certain conditions the plasma time difference is large enough to be observable. The experimental aspects in realizing such a discrimination in germanium detectors is discussed.

  8. Spectrum of recoil nucleons in quasi-elastic neutrino-nucleus interactions

    Energy Technology Data Exchange (ETDEWEB)

    Juszczak, C.; Nowak, J.A.; Sobczyk, J.T. [Wroclaw University, Institute of Theoretical Physics, Wroclaw (Poland)

    2005-02-01

    We have analyzed the consequences of introducing the local density approximation combined with an effective nuclear momentum-dependent potential into the CC quasi-elastic neutrino-nucleus scattering. We note that the distribution of recoil nucleons momenta becomes smooth for low momentum values and the sharp threshold is removed. Our results may be relevant for Sci-Fi detector analysis of K2K experiments. The total amount of observed recoil protons is reduced because some of them remain bound inside the nucleus. We compare theoretical predictions for a probability of such events with the results given by NUX+FLUKA MC simulations. (orig.)

  9. Bose-Einstein condensates in an optical cavity with sub-recoil bandwidth

    Science.gov (United States)

    Klinder, J.; Keßler, H.; Georges, Ch.; Vargas, J.; Hemmerich, A.

    2016-12-01

    This article provides a brief synopsis of our recent work on the interaction of Bose-Einstein condensates with the light field inside an optical cavity exhibiting a bandwidth on the order of the recoil frequency. Three different coupling scenarios are discussed giving rise to different physical phenomena at the borderline between the fields of quantum optics and many-body physics. This includes sub-recoil opto-mechanical cooling, cavity-controlled matter wave superradiance and the emergence of a superradiant superfluid or a superradiant Mott insulating many-body phase in a self-organized intra-cavity optical lattice with retarded infinite range interactions.

  10. Creation of individual ideally shaped stents using multi-slice CT: in vitro results from the semi-automatic virtual stent (SAVS) designer.

    Science.gov (United States)

    Hyodoh, Hideki; Katagiri, Yoshimi; Sakai, Toyohiko; Hyodoh, Kazusa; Akiba, Hidenari; Hareyama, Masato

    2005-08-01

    To plan stent-grafting for thoracic aortic aneurysm with complicated morphology, we created a virtual stent-grafting program [Semi Automatic Virtual Stent (SAVS) designer] using three-dimensional CT data. The usefulness of the SAVS designer was evaluated by measurement of transformed anatomical and straight stents. Curved model images (source, multi-planer reconstruction and volume rendering) were created, and a hollow virtual stent was produced by the SAVS designer. A straight Nitinol stent was transformed to match the curved configuration of the virtual stent. The accuracy of the anatomical stent was evaluated by experimental strain phantom studies in comparison with the straight stent. Mean separation length was 0 mm in the anatomical stent [22 mm outer diameter (OD)] and 5 mm in the straight stent (22 mm OD). The straight stent strain voltage was four times that of the anatomical stent at the stent end. The anatomical stent is useful because it fits the curved structure of the aorta and reduces the strain force compared to the straight stent. The SAVS designer can help to design and produce the anatomical stent.

  11. AMS INSIGHT--absorbable metal stent implantation for treatment of below-the-knee critical limb ischemia: 6-month analysis.

    Science.gov (United States)

    Bosiers, Marc; Peeters, Patrick; D'Archambeau, Olivier; Hendriks, Jeroen; Pilger, Ernst; Düber, Christoph; Zeller, Thomas; Gussmann, Andreas; Lohle, Paul N M; Minar, Erich; Scheinert, Dierk; Hausegger, Klaus; Schulte, Karl-Ludwig; Verbist, Jürgen; Deloose, Koen; Lammer, J

    2009-05-01

    Endoluminal treatment of infrapopliteal artery lesions is a matter of controversy. Bioabsorbable stents are discussed as a means to combine mechanical prevention of vessel recoil with the advantages of long-term perspectives. The possibility of not having a permanent metallic implant could permit the occurrence of positive remodeling with lumen enlargement to compensate for the development of new lesions. The present study was designed to investigate the safety of absorbable metal stents (AMSs) in the infrapopliteal arteries based on 1- and 6-month clinical follow-up and efficacy based on 6-month angiographic patency. One hundred seventeen patients with 149 lesions with chronic limb ischemia (CLI) were randomized to implantation of an AMS (60 patients, 74 lesions) or stand-alone percutaneous transluminal angioplasty (PTA; 57 patients, 75 lesions). Seven PTA-group patients "crossed over" to AMS stenting. The study population consisted of patients with symptomatic CLI (Rutherford categories 4 and 5) and de novo stenotic (>50%) or occlusive atherosclerotic disease of the infrapopliteal arteries who presented with a reference diameter of between 3.0 and 3.5 mm and a lesion length of <15 mm. The primary safety endpoint was defined as absence of major amputation and/or death within 30 days after index intervention and the primary efficacy endpoint was the 6-month angiographic patency rate as confirmed by core-lab quantitative vessel analysis. The 30-day complication rate was 5.3% (3/57) and 5.0% (3/60) in patien