WorldWideScience

Sample records for asymmetric vascular stent

  1. Angiographic analysis of animal model aneurysms treated with novel polyurethane asymmetric vascular stent (P-AVS): feasibility study

    OpenAIRE

    Ionita, Ciprian N; Dohatcu, Andreea; Sinelnikov, Andrey; Sherman, Jason; Keleshis, Christos; Paciorek, Ann M; Hoffmann, K R; Bednarek, D. R.; Rudin, S.

    2009-01-01

    Image-guided endovascular intervention (EIGI), using new flow modifying endovascular devices for intracranial aneurysm treatment is an active area of stroke research. The new polyurethane-asymmetric vascular stent (P-AVS), a vascular stent partially covered with a polyurethane-based patch, is used to cover the aneurysm neck, thus occluding flow into the aneurysm. This study involves angiographic imaging of partially covered aneurysm orifices. This particular situation could occur when the vas...

  2. Assessment of contrast flow modification in aneurysms treated with closed-cell self-deploying asymmetric vascular stents (SAVS)

    Science.gov (United States)

    Ionita, Ciprian N.; Wang, Weiyuan; Bednarek, Daniel R.; Rudin, Stephen

    2010-03-01

    The Asymmetric Vascular Stent (AVS) for intracranial aneurysm (IA) treatment is an experimental device, specially designed for intra-aneurysmal blood flow diversion and thrombosis promotion. The stent has a low-porous patch to cover only the aneurysm neck while the rest of the stent is very porous to avoid blockage of adjacent branches. The latest AVS design is similar to state-of-art, closed-cell, self-expanding, neurovascular stent. The stents were used to treat sixteen rabbit-elastase aneurysm models. The treatment effect was analyzed using normalized-time-density-curves (NTDC) measured by pixel-value integration over a region-of-interest containing the aneurysm. Normalization constant was the total bolus injection determined angiographically. Based on NTDC measurement, five quantities were derived to describe the contrast flow. Two are related to the amount of contrast entering the aneurysm: NTDC peak and NTDC input slope. The other three are related to contrast presence in the aneurysmal dome: time-to-peak (TTP), wash-out-time (WOT) and mean-transit-time (MTT). Flow modification descriptions using the contrast related quantities were expressed as a pre-/post-stented NTDC parameter ratio, while the time related quantities were expressed as a post-/prestented ratio, so that ratios smaller than one indicate a desired effect. Thirteen aneurysms were treated successfully and achieved significant aneurysm occlusion. For these cases, the resulting average parameters were: peak-ratio=0.17+0.21; input-slope-ratio=0.19+/-0.24, TTP-ratio=0.17+0.21, WOT-ratio=0.58+/-0.73 and MTT-ratio=0.65+/-0.97). All the quantities revealed decreased aneurysmal flow due to blood flow diversion using the new self-expanding asymmetrical vascular stent (SAVS). Treatment outcome results and angiographic analysis indicate that the new self-deploying stent design has great potential for clinical implementation.

  3. Angiographic analysis of animal model aneurysms treated with novel polyurethane asymmetric vascular stent (P-AVS): feasibility study

    Science.gov (United States)

    Ionita, Ciprian N.; Dohatcu, Andreea; Sinelnikov, Andrey; Sherman, Jason; Keleshis, Christos; Paciorek, Ann M.; Hoffmann, K. R.; Bednarek, D. R.; Rudin, S.

    2009-02-01

    Image-guided endovascular intervention (EIGI), using new flow modifying endovascular devices for intracranial aneurysm treatment is an active area of stroke research. The new polyurethane-asymmetric vascular stent (P-AVS), a vascular stent partially covered with a polyurethane-based patch, is used to cover the aneurysm neck, thus occluding flow into the aneurysm. This study involves angiographic imaging of partially covered aneurysm orifices. This particular situation could occur when the vascular geometry does not allow full aneurysm coverage. Four standard in-vivo rabbit-model aneurysms were investigated; two had stent patches placed over the distal region of the aneurysm orifice while the other two had stent patches placed over the proximal region of the aneurysm orifice. Angiographic analysis was used to evaluate aneurysm blood flow before and immediately after stenting and at four-week follow-up. The treatment results were also evaluated using histology on the aneurysm dome and electron microscopy on the aneurysm neck. Post-stenting angiographic flow analysis revealed aneurysmal flow reduction in all cases with faster flow in the distally-covered case and very slow flow and prolonged pooling for proximal-coverage. At follow-up, proximally-covered aneurysms showed full dome occlusion. The electron microscopy showed a remnant neck in both distally-placed stent cases but complete coverage in the proximally-placed stent cases. Thus, direct flow (impingement jet) removal from the aneurysm dome, as indicated by angiograms in the proximally-covered case, was sufficient to cause full aneurysm healing in four weeks; however, aneurysm healing was not complete for the distally-covered case. These results support further investigations into the treatment of aneurysms by flow-modification using partial aneurysm-orifice coverage.

  4. Endovascular image-guided treatment of in-vivo model aneurysms with asymmetric vascular stents (AVS): evaluation with time-density curve angiographic analysis and histology

    Science.gov (United States)

    Dohatcu, A.; Ionita, C. N.; Paciorek, A.; Bednarek, D. R.; Hoffmann, K. R.; Rudin, S.

    2008-03-01

    In this study, we compare the results obtained from Time-Density Curve (TDC) analysis of angiographic imaging sequences with histological evaluation for a rabbit aneurysm model treated with standard stents and new asymmetric vascular stents (AVS) placed by image-guided endovascular deployment. AVSs are stents having a low-porosity patch region designed to cover the aneurysm neck and occlude blood flow inside. To evaluate the AVSs, rabbits with elastase-induced aneurysm models (n=20) were divided into three groups: the first (n=10) was treated with an AVS, the second (n=5) with a non-patch standard coronary stent, and third was untreated as a control (n=5). We used TDC analysis to measure how much contrast media entered the aneurysm before and after treatment. TDCs track contrast-media-density changes as a function of time over the region of interest in x-ray DSA cine-sequences. After 28 days, the animals were sacrificed and the explanted specimens were histologically evaluated. The first group showed an average reduction of contrast flow into the aneurysm of 95% after treatment with an AVS with fully developed thrombus at 28 days follow-up. The rabbits treated with standard stents showed an increase in TDC residency time after treatment and partial-thrombogenesis. The untreated control aneurysms displayed no reduction in flow and were still patent at follow-up. The quantitative TDC analysis findings were confirmed by histological evaluation suggesting that the new AVS has great potential as a definitive treatment for cerebro-vascular aneurysms and that angiographic TDC analysis can provide in-vivo verification.

  5. Biomimicry, vascular restenosis and coronary stents.

    Science.gov (United States)

    Schwartz, R S; van der Giessen, W J; Holmes, D R

    1998-01-01

    Biomimicry is in its earliest stages and is being considered in the realm of tissue engineering. If arterial implants are to limit neointimal thickening, purely passive structures cannot succeed. Bioactivity must be present, either by pharmacologic intervention or by fabricating a 'living stent' that contains active cellular material. As tissue engineering evolves, useful solutions will emerge from applying this knowledge directly to vascular biologic problems resulting from angioplasty, stenting, and vascular prosthesis research.

  6. Society for Vascular Surgery Vascular Registry evaluation of stent cell design on carotid artery stenting outcomes.

    Science.gov (United States)

    Jim, Jeffrey; Rubin, Brian G; Landis, Gregg S; Kenwood, Christopher T; Siami, Flora S; Sicard, Gregorio A

    2011-07-01

    The Society for Vascular Surgery (SVS) Vascular Registry (VR) collects data on outcomes of carotid endarterectomy and carotid artery stenting (CAS). The purpose of this study was to evaluate the impact of open vs closed cell stent design on the in-hospital and 30-day outcome of CAS. The VR collects provider-reported data on patients using a Web-based database. Data were analyzed both in-hospital and at 30 days postprocedure. The primary outcome is combined death/stroke/myocardial infarction (MI). As of October 14, 2009, there were 4337 CAS with discharge data and 2397 with 30-day data. Open cell stents (OPEN) were used in 3451 patients (79.6%), and closed cell stents (CLOSED) were used in 866 patients (20.4%). Baseline demographics showed no differences in age, gender, race, and ethnicity. However, the OPEN group had more patients with atherosclerosis (74.5% vs 67.4%; P = .0003) as the etiology of carotid artery disease. The OPEN group also had a higher prevalence of preprocedural stroke (25.8% vs 21.4%; P = .0079), chronic obstructive pulmonary disease (COPD; 21.0% vs 17.6%; P = .0277), cardiac arrhythmia (14.7% vs 11.4%; P = .0108), valvular heart disease (7.4% vs 3.7%; P differences in the in-hospital or 30-day outcomes between the OPEN and CLOSED patients. Further subgroup analyses demonstrated symptomatic patients had a higher event rate than the asymptomatic cohort in both the OPEN and CLOSED groups. Among symptomatic patients, the OPEN patients had a lower (0.43% vs 1.41%; P = .0349) rate of in-hospital mortality with no difference in stroke or transient ischemic attack (TIA). There were no differences in 30-day event rates. In asymptomatic patients, there were also no statistically significant differences between the OPEN and CLOSED groups. After risk adjustment, there remained no statistically significant differences between groups of the primary endpoint (death/stroke/MI) during in-hospital or 30 days. In-hospital and 30-day outcomes after CAS were not

  7. [Numerical modeling of shape memory alloy vascular stent's self-expandable progress and "optimized grid" of stent].

    Science.gov (United States)

    Xu, Qiang; Liu, Yulan; Wang, Biao; He, Jin

    2008-10-01

    Vascular stent is an important medical appliance for angiocardiopathy. Its key deformation process is the expandable progress of stent in the vessel. The important deformation behaviour corresponds to two mechanics targets: deformation and stress. This paper is devoted to the research and development of vascular stent with proprietary intellectual property rights. The design of NiTinol self-expandable stent is optimized by means of finite element software. ANSYS is used to build the finite element simulation model of vascular stent; the molding material is NiTinol shape memory alloy. To cope with the factors that affect the structure of stent, the shape of grid and so on, the self-expanding process of Nitinol stent is simulated through computer. By making a comparison between two kinds of stents with similar grid structure, we present a new concept of "Optimized Grid" of stent.

  8. Fluid-attenuated inversion recovery vascular hyperintensities in predicting cerebral hyperperfusion after intracranial arterial stenting

    Energy Technology Data Exchange (ETDEWEB)

    Wan, Chih-Cheng; Chen, David Yen-Ting; Tseng, Ying-Chi; Lee, Kun-Yu; Chiang, Chen-Hua; Chen, Chi-Jen [Taipei Medical University, Department of Radiology, Shuang-Ho Hospital, New Taipei City (China); Taipei Medical University, School of Medicine, College of Medicine, Taipei (China); Yan, Feng-Xian [Taipei Medical University, Department of Radiology, Shuang-Ho Hospital, New Taipei City (China)

    2017-08-15

    No reliable imaging sign predicting cerebral hyperperfusion after intracranial arterial stenting (IAS) had been described in the literature. This study evaluated the effect of fluid-attenuated inversion recovery vascular hyperintensities (FVHs), also called hyperintense vessel sign on T2-weighted fluid-attenuated inversion recovery (T2-FLAIR) MR images, in predicting significant increase in cerebral blood flow (CBF) defined by arterial spin labeling (ASL) after IAS. We reviewed ASL CBF images and T2-FLAIR MR images before (D0), 1 day after (D1), and 3 days after (D3) IAS of 16 patients. T1-weighted MR images were used as cerebral maps for calculating CBF. The changes in CBF values after IAS were calculated in and compared among stenting and nonstenting vascular territories. An increase more than 50% of CBF was considered as hyperperfusion. The effect of FVHs in predicting hyperperfusion was calculated. The D1 CBF value was significantly higher than the D0 CBF value in stenting vascular, contralateral anterior cerebral artery, contralateral middle cerebral artery, and contralateral posterior cerebral artery (PCA) territories (all P <.05). The D1 and D3 CBF values were significantly higher than the D0 CBF value in overall vascular (P <.001), overall nonstenting vascular (P <.001), and ipsilateral PCA (P <.05) territories. The rate of more than 50% increases in CBF was significantly higher in patients who exhibited asymmetric FVHs than in those who did not exhibit these findings. FVHs could be a critical predictor of a significant increase in CBF after IAS. (orig.)

  9. Fabrication and in vitro deployment of a laser-activated shape memory polymer vascular stent

    Directory of Open Access Journals (Sweden)

    Matthews Dennis L

    2007-11-01

    Full Text Available Abstract Background Vascular stents are small tubular scaffolds used in the treatment of arterial stenosis (narrowing of the vessel. Most vascular stents are metallic and are deployed either by balloon expansion or by self-expansion. A shape memory polymer (SMP stent may enhance flexibility, compliance, and drug elution compared to its current metallic counterparts. The purpose of this study was to describe the fabrication of a laser-activated SMP stent and demonstrate photothermal expansion of the stent in an in vitro artery model. Methods A novel SMP stent was fabricated from thermoplastic polyurethane. A solid SMP tube formed by dip coating a stainless steel pin was laser-etched to create the mesh pattern of the finished stent. The stent was crimped over a fiber-optic cylindrical light diffuser coupled to an infrared diode laser. Photothermal actuation of the stent was performed in a water-filled mock artery. Results At a physiological flow rate, the stent did not fully expand at the maximum laser power (8.6 W due to convective cooling. However, under zero flow, simulating the technique of endovascular flow occlusion, complete laser actuation was achieved in the mock artery at a laser power of ~8 W. Conclusion We have shown the design and fabrication of an SMP stent and a means of light delivery for photothermal actuation. Though further studies are required to optimize the device and assess thermal tissue damage, photothermal actuation of the SMP stent was demonstrated.

  10. Fabrication and In Vitro Deployment of a Laser-Activated Shape Memory Polymer Vascular Stent

    Energy Technology Data Exchange (ETDEWEB)

    Baer, G M; Small IV, W; Wilson, T S; Benett, W J; Matthews, D L; Hartman, J; Maitland, D J

    2007-04-25

    Vascular stents are small tubular scaffolds used in the treatment of arterial stenosis (narrowing of the vessel). Most vascular stents are metallic and are deployed either by balloon expansion or by self-expansion. A shape memory polymer (SMP) stent may enhance flexibility, compliance, and drug elution compared to its current metallic counterparts. The purpose of this study was to describe the fabrication of a laser-activated SMP stent and demonstrate photothermal expansion of the stent in an in vitro artery model. A novel SMP stent was fabricated from thermoplastic polyurethane. A solid SMP tube formed by dip coating a stainless steel pin was laser-etched to create the mesh pattern of the finished stent. The stent was crimped over a fiber-optic cylindrical light diffuser coupled to an infrared diode laser. Photothermal actuation of the stent was performed in a water-filled mock artery. At a physiological flow rate, the stent did not fully expand at the maximum laser power (8.6 W) due to convective cooling. However, under zero flow, simulating the technique of endovascular flow occlusion, complete laser actuation was achieved in the mock artery at a laser power of {approx}8 W. We have shown the design and fabrication of an SMP stent and a means of light delivery for photothermal actuation. Though further studies are required to optimize the device and assess thermal tissue damage, photothermal actuation of the SMP stent was demonstrated.

  11. Asymmetric dimethylarginine: a possible link between vascular disease and dementia.

    Science.gov (United States)

    Asif, Muhammad; Soiza, Roy Louis; McEvoy, Mark; Mangoni, Arduino A

    2013-05-01

    There is good epidemiological evidence that vascular disease predisposes to cognitive decline and dementia. The impact of vascular disease on dementia is likely to increase further because of the poor diagnosis and management of vascular risk factors, the increase in life expectancy, and the improved survival following major cardiovascular events, e.g. acute stroke. It is estimated that the adequate management of vascular risk factors, with pharmacological and/or nonpharmacological interventions, might result in a 50% reduction in the forecasted dementia prevalence. The exact mechanisms by which vascular risk factors and vascular disease adversely affect brain function remain unclear, but it is hypothesized that endothelial dysfunction plays an important role. Reduced synthesis and availability of endothelial nitric oxide (NO) may contribute to the development of dementia by at least two mechanisms: (1) favoring the onset and progression of atherosclerosis, vasoconstriction, and impaired cerebral blood flow regulation; and (2) reduced neuroprotection.Several studies have shown that asymmetric dimethylarginine (ADMA), an endogenous methylated form of the amino acid L-arginine, inhibits NO synthesis and favors oxidative stress and vascular damage. Unlike NO, ADMA concentrations are relatively stable and can be accurately measured in plasma. There is good evidence that higher plasma ADMA concentrations favor atherosclerosis and independently predict adverse cardiovascular and cerebrovascular outcomes in several patient groups. ADMA might represent a unifying pathophysiological pathway linking the presence of vascular risk factors with the onset and progression of cognitive decline and dementia. This review discusses the biological role of ADMA, its potential contribution to the onset and progression of dementia through vascular disease and atherosclerosis, the available evidence linking ADMA with cognitive impairment and dementia, and the strategies to characterize

  12. French multicenter experience with the GORE TIGRIS Vascular Stent in superficial femoral and popliteal arteries.

    Science.gov (United States)

    Sibé, Maxime; Kaladji, Adrien; Boirat, Claire; Cardon, Alain; Chaufour, Xavier; Bossavy, Jean-Pierre; Saint-Lebes, Bertrand

    2017-05-01

    Preliminary results in small single-center studies after stenting with the GORE TIGRIS Vascular Stent (W. L. Gore & Associates, Flagstaff, Ariz) show promising short-term primary patency rates, but larger, multicenter studies are needed. This study therefore investigated the performance of the GORE TIGRIS Vascular Stent at three different centers in France in patients with symptomatic peripheral artery disease. This retrospective, single-arm, multicenter cohort study included 215 patients with peripheral artery disease (Rutherford-Becker category 2-6) who were treated with the GORE TIGRIS Vascular Stent, a dual-component stent consisting of a nitinol wire frame combined with a fluoropolymer-interconnecting structure. The efficacy end point was primary patency defined by freedom from binary restenosis as derived by duplex ultrasound imaging until 2 years after the intervention. Primary, secondary, and primary assisted patency rates at 3, 6, 12, 18, and 24 months were estimated by Kaplan-Meier analysis. The GORE TIGRIS Vascular Stent was used to successfully treat 239 lesions, of which 141 lesions were located in the superficial femoral artery and 98 in the popliteal artery. Patients were a mean age of 74 ± 12 years. Mean lesion length was 86.8 ± 44.7 mm. After 12 and 24 months, the overall primary patency rates were 81.5% and 67.2%, respectively, and primary assisted patency was 94.9% and 84.8%. Secondary patency was achieved in 99.1% at 24 months. Our multicenter experience with the GORE TIGRIS Vascular Stent demonstrates continued good results at 2 years for endovascular treatment of challenging obstructive superficial femoral artery and popliteal artery disease. Copyright © 2017 Society for Vascular Surgery. Published by Elsevier Inc. All rights reserved.

  13. Flow modification in canine intracranial aneurysm model by an asymmetric stent: studies using digital subtraction angiography (DSA) and image-based computational fluid dynamics (CFD) analyses

    Science.gov (United States)

    Hoi, Yiemeng; Ionita, Ciprian N.; Tranquebar, Rekha V.; Hoffmann, Kenneth R.; Woodward, Scott, H.; Taulbee, Dale B.; Meng, Hui; Rudin, Stephen

    2011-01-01

    An asymmetric stent with low porosity patch across the intracranial aneurysm neck and high porosity elsewhere is designed to modify the flow to result in thrombogenesis and occlusion of the aneurysm and yet to reduce the possibility of also occluding adjacent perforator vessels. The purposes of this study are to evaluate the flow field induced by an asymmetric stent using both numerical and digital subtraction angiography (DSA) methods and to quantify the flow dynamics of an asymmetric stent in an in vivo aneurysm model. We created a vein-pouch aneurysm model on the canine carotid artery. An asymmetric stent was implanted at the aneurysm, with 25% porosity across the aneurysm neck and 80% porosity elsewhere. The aneurysm geometry, before and after stent implantation, was acquired using cone beam CT and reconstructed for computational fluid dynamics (CFD) analysis. Both steady-state and pulsatile flow conditions using the measured waveforms from the aneurysm model were studied. To reduce computational costs, we modeled the asymmetric stent effect by specifying a pressure drop over the layer across the aneurysm orifice where the low porosity patch was located. From the CFD results, we found the asymmetric stent reduced the inflow into the aneurysm by 51%, and appeared to create a stasis-like environment which favors thrombus formation. The DSA sequences also showed substantial flow reduction into the aneurysm. Asymmetric stents may be a viable image guided intervention for treating intracranial aneurysms with desired flow modification features. PMID:21666881

  14. Flow modification in canine intracranial aneurysm model by an asymmetric stent: studies using digital subtraction angiography (DSA) and image-based computational fluid dynamics (CFD) analyses

    Science.gov (United States)

    Hoi, Yiemeng; Ionita, Ciprian N.; Tranquebar, Rekha V.; Hoffmann, Kenneth R.; Woodward, Scott H.; Taulbee, Dale B.; Meng, Hui; Rudin, Stephen

    2006-03-01

    An asymmetric stent with low porosity patch across the intracranial aneurysm neck and high porosity elsewhere is designed to modify the flow to result in thrombogenesis and occlusion of the aneurysm and yet to reduce the possibility of also occluding adjacent perforator vessels. The purposes of this study are to evaluate the flow field induced by an asymmetric stent using both numerical and digital subtraction angiography (DSA) methods and to quantify the flow dynamics of an asymmetric stent in an in vivo aneurysm model. We created a vein-pouch aneurysm model on the canine carotid artery. An asymmetric stent was implanted at the aneurysm, with 25% porosity across the aneurysm neck and 80% porosity elsewhere. The aneurysm geometry, before and after stent implantation, was acquired using cone beam CT and reconstructed for computational fluid dynamics (CFD) analysis. Both steady-state and pulsatile flow conditions using the measured waveforms from the aneurysm model were studied. To reduce computational costs, we modeled the asymmetric stent effect by specifying a pressure drop over the layer across the aneurysm orifice where the low porosity patch was located. From the CFD results, we found the asymmetric stent reduced the inflow into the aneurysm by 51%, and appeared to create a stasis-like environment which favors thrombus formation. The DSA sequences also showed substantial flow reduction into the aneurysm. Asymmetric stents may be a viable image guided intervention for treating intracranial aneurysms with desired flow modification features.

  15. Enhanced biocompatibility of CD47-functionalized vascular stents.

    Science.gov (United States)

    Slee, Joshua B; Alferiev, Ivan S; Nagaswami, Chandrasekaran; Weisel, John W; Levy, Robert J; Fishbein, Ilia; Stachelek, Stanley J

    2016-05-01

    The effectiveness of endovascular stents is hindered by in-stent restenosis (ISR), a secondary re-obstruction of treated arteries due to unresolved inflammation and activation of smooth muscle cells in the arterial wall. We previously demonstrated that immobilized CD47, a ubiquitously expressed transmembrane protein with an established role in immune evasion, can confer biocompatibility when appended to polymeric surfaces. In present studies, we test the hypothesis that CD47 immobilized onto metallic surfaces of stents can effectively inhibit the inflammatory response thus mitigating ISR. Recombinant CD47 (recCD47) or a peptide sequence corresponding to the Ig domain of CD47 (pepCD47), were attached to the surfaces of both 316L-grade stainless steel foils and stents using bisphosphonate coordination chemistry and thiol-based conjugation reactions to assess the anti-inflammatory properties of CD47-functionalized surfaces. Initial in vitro and ex vivo analysis demonstrated that both recCD47 and pepCD47 significantly reduced inflammatory cell attachment to steel surfaces without impeding on endothelial cell retention and expansion. Using a rat carotid stent model, we showed that pepCD47-functionalized stents prevented fibrin and platelet thrombus deposition, inhibited inflammatory cell attachment, and reduced restenosis by 30%. It is concluded that CD47-modified stent surfaces mitigate platelet and inflammatory cell attachment, thereby disrupting ISR pathophysiology. Copyright © 2016 Elsevier Ltd. All rights reserved.

  16. Vascular Responses to Drug Eluting Stents: Importance of Delayed Healing

    National Research Council Canada - National Science Library

    Finn, Aloke V; Nakazawa, Gaku; Joner, Michael; Kolodgie, Frank D; Mont, Erik K; Gold, Herman K; Virmani, Renu

    2007-01-01

    Polymer-based sirolimus- (Cypher) and paclitaxel-eluting (Taxus) drug eluting stents have become the treatment of choice for patients with symptomatic coronary artery disease undergoing percutaneous coronary intervention (PCI...

  17. Association between the synthetic vascular stent used for abdominal aortic aneurysm and generalized granuloma annulare

    Directory of Open Access Journals (Sweden)

    Han-Chi Tseng

    2015-09-01

    Full Text Available The etiology of granuloma annulare (GA remains unknown, although several eliciting factors have been proposed. We herein present the case of an 81-year-old man who developed generalized erythematous annular plaques 6 months after engraftment of a vascular stent for abdominal aneurysm repair. Based on the diagnosis of generalized GA and the patient's age, we treated him with psoralens plus ultraviolet A therapy. The treatment response was good. This is the first report showing the association between vascular stent and generalized GA.

  18. Bioresorbable vascular scaffold for coronary in-stent restenosis: A novel concept

    Directory of Open Access Journals (Sweden)

    Surender Deora

    2014-07-01

    Full Text Available The management of patients with significant in-stent restenosis (ISR with drug-eluting stent is still not well defined. Various treatment modalities include plain old balloon angioplasty (POBA, metallic stent, cutting or scoring balloon and drug-eluting balloon (DEB. Bioresorbable vascular scaffold (BVS is the latest technology for the treatment of de novo coronary artery lesions. The use of BVS in ISR is based on the rationale of local drug delivery as achieved by DEB without the permanent bi-layer of metal and also stabilizes dissection flaps and prevents acute recoil as provided by metallic stent. To the best of our knowledge this is the first case report of the use of BVS in patient with ISR.

  19. Comparison of Temporary Open Arterial Revascularization Using Stent Grafts vs. Standard Vascular Shunts in a Porcine (Sus scrofa) Model

    Science.gov (United States)

    2017-01-24

    feasible strategy for damage control management of peripheral vascular injury and offers increased blood flow when compared to temporary shunts...survival model of porcine vascular injury . Methods: 12 Yorkshire-cross swine received a 2cm long near-circumferential defect in the iliac arteries. A14...shunts was greater than that of the stent grafts. Conclusion: Open sutureless direct site repair using stent grafts to treat vascular injury is a

  20. Perspective: carotid stenting and the history of disruptive technology in vascular surgery.

    Science.gov (United States)

    Veith, Frank J

    2008-06-01

    This article defines disruptive technology and discusses such technologies in Vascular Surgery. It considers the question: Is carotid artery stenting (CAS) a disruptive technology? Although CAS will impact positively on the treatment of carotid bifurcation disease, it will probably never displace carotid endarterectomy in the majority of patients. The precise role of CAS remains to be determined.

  1. Preparation and Characterization of New Nano-Composite Scaffolds Loaded With Vascular Stents

    Directory of Open Access Journals (Sweden)

    Tianbin Ren

    2012-03-01

    Full Text Available In this study, vascular stents were fabricated from poly (lactide-ε-caprolactone/collagen/nano-hydroxyapatite (PLCL/Col/nHA by electrospinning, and the surface morphology and breaking strength were observed or measured through scanning electron microscopy and tensile tests. The anti-clotting properties of stents were evaluated for anticoagulation surfaces modified by the electrostatic layer-by-layer self-assembly technique. In addition, nano-composite scaffolds of poly (lactic-co-glycolic acid/polycapr-olactone/nano-hydroxyapatite (PLGA/PCL/nHA loaded with the vascular stents were prepared by thermoforming-particle leaching and their basic performance and osteogenesis were tested in vitro and in vivo. The results show that the PLCL/Col/nHA stents and PLGA/PCL/nHA nano-composite scaffolds had good surface structures, mechanical properties, biocompatibility and could guide bone regeneration. These may provide a new way to build vascularized-tissue engineered bone to repair large bone defects in bone tissue engineering.

  2. Coronary artery aneurysm formation following implantation of a bioresorbable vascular scaffold for in-stent restenosis.

    Science.gov (United States)

    García-Guimaraes, Marcos; Cuesta, Javier; Alvarado, Teresa; Rivero, Fernando; Bastante, Teresa; Benedicto, Amparo; Alfonso, Fernando

    2017-06-01

    Coronary artery aneurysm (CAA) formation is a rare complication of coronary intervention that may develop after implantation of bare-metal or drug-eluting stents. The etiology of this entity appears to be multifactorial and its prognosis is poorly understood, but it has been associated with an increased risk of stent thrombosis. To date few cases of CAAs related to bioresorbable vascular scaffold (BVS) implantation have been reported, and the development of CAA after BVS implantation for the treatment of in-stent restenosis (ISR) has not been previously described. Here we present two cases of CAA formation after BVS, which represent the first demonstration of CAA formation after the use of BVS for ISR. Copyright © 2017 Sociedade Portuguesa de Cardiologia. Publicado por Elsevier España, S.L.U. All rights reserved.

  3. Vascular Anatomy Predicts the Risk of Cerebral Ischemia in Patients Randomized to Carotid Stenting Versus Endarterectomy.

    Science.gov (United States)

    Müller, Mandy D; Ahlhelm, Frank J; von Hessling, Alexander; Doig, David; Nederkoorn, Paul J; Macdonald, Sumaira; Lyrer, Philippe A; van der Lugt, Aad; Hendrikse, Jeroen; Stippich, Christoph; van der Worp, H Bart; Richards, Toby; Brown, Martin M; Engelter, Stefan T; Bonati, Leo H

    2017-05-01

    Complex vascular anatomy might increase the risk of procedural stroke during carotid artery stenting (CAS). Randomized controlled trial evidence that vascular anatomy should inform the choice between CAS and carotid endarterectomy (CEA) has been lacking. One-hundred eighty-four patients with symptomatic internal carotid artery stenosis who were randomly assigned to CAS or CEA in the ICSS (International Carotid Stenting Study) underwent magnetic resonance (n=126) or computed tomographic angiography (n=58) at baseline and brain magnetic resonance imaging before and after treatment. We investigated the association between aortic arch configuration, angles of supra-aortic arteries, degree, length of stenosis, and plaque ulceration with the presence of ≥1 new ischemic brain lesion on diffusion-weighted magnetic resonance imaging (DWI+) after treatment. Forty-nine of 97 patients in the CAS group (51%) and 14 of 87 in the CEA group (16%) were DWI+ (odds ratio [OR], 6.0; 95% confidence interval [CI], 2.9-12.4; Pcarotid artery angle (≥60° versus carotid artery angle was ≥60° (OR, 11.8; 95% CI, 4.1-34.1) than if it was carotid artery tortuosity increase the risk of cerebral ischemia during CAS, but not during CEA. Vascular anatomy should be taken into account when selecting patients for stenting. URL: http://www.isrctn.com/ISRCTN25337470. Unique identifier: ISRCTN25337470. © 2017 American Heart Association, Inc.

  4. MRI compatible Nb-Ta-Zr alloys used for vascular stents: optimization for mechanical properties.

    Science.gov (United States)

    Li, Hui-Zhe; Xu, Jian

    2014-04-01

    With the increased usage of magnetic resonance imaging (MRI) as a diagnostic tool in clinic, the currently-used metals for vascular stents, such as 316L stainless steel (SS), Co-Cr alloys and Ni-Ti alloys, are challenged by their unsatisfactory MRI compatibility, due to their constituents containing ferromagnetic elements. To provide more MRI compatible vascular stents, the Nb-xTa-2Zr (30≤x≤70) series alloys were selected in the current work. Several key properties of these alloys were optimized in terms of stent requirements, including magnetic susceptibility, elastic modulus and tensile properties. In the as-cast state, a single-phase solid solution with bcc structure was formed in the alloys. The volume magnetic susceptibility (χv) and Young's modulus (E) of the alloys scaled linearly with the Ta content. Increasing the Ta content gave rise to the decreased χv and the increased E, together with the elevated yield strength but less-changed elongation. From multiple requirements for the stents, the Nb-60Ta-2Zr alloy exhibits an optimal properties, including the χv of about 3% of the 316L SS, the E of 142GPa superior to pure niobium, high mass density of 12.03g/cm(3) favored to the X-ray visibility, yield strength of ~330MPa comparable to the 316L SS and a elongation of ~24%. These remarkable advantages make it quite promising as a new candidate of stent metals. Copyright © 2013 Elsevier Ltd. All rights reserved.

  5. [Proposed model of vascular trauma by mean of mechanical characterization of endovascular prostheses (stents) based on structural analysis by FEA].

    Science.gov (United States)

    Bustamante, John; Uribe, Pablo; Sosa, Mauricio; Valencia, Raúl

    2016-01-01

    The accumulated evidence on angioplasty techniques with stents has raised a controversy about the factors that influence the final vascular response. Indeed, several studies have shown there might be re-stenosis between 30% to 40% about 6 months after placement, relating to the design of the device as one of the main causes. This paper proposes the functional characterization of endovascular stents, analyzing its mechanical influence in the vascular system and predicting implicit traumatic factors in the vessel. A structural analysis was made for several computational models of endovascular stents using Finite Element Analysis in order to predict the mechanical behavior and the vascular trauma. In this way, the stents were considered as tubular devices composed of multiple links under radial pressure loads, reflecting stress concentration effects. The analysis allowed to visualize how the geometry of stents is adjusted under several load conditions, in order to obtain the response of "solid-solid" interaction between the stent and the arterial wall. Thus, an analysis was performed in order to calculate stress, and a conceptual model that explains its mechanical impact on the stent-vessel interaction, was raised, to infer on the functionality from the design of the devices. The proposed conceptual model allows to determine the relationship between the conditions of mechanical interaction of the stents, and warns about the effects in what would be the operation of the device on the vascular environment. Copyright © 2016 Instituto Nacional de Cardiología Ignacio Chávez. Publicado por Masson Doyma México S.A. All rights reserved.

  6. [Pulmonary reperfusion syndrome after pulmonary stent implants in a patient with vascular tortuosity syndrome].

    Science.gov (United States)

    Berenguer Potenciano, M; Piris Borregas, S; Mendoza Soto, A; Velasco Bayon, J M; Caro Barri, A

    2015-01-01

    Vascular tortuosity syndrome is a rare genetic disorder that causes tortuosity and stenosis of the pulmonary, systemic and / or coronary circulations. As a result of treatment of pulmonary stenosis, symptoms of pulmonary edema, known as lung reperfusion syndrome, may occur. The case is presented of an adolescent patient with vascular tortuosity syndrome who presented with a pulmonary reperfusion syndrome after multiple stent implants in the left pulmonary artery. After the procedure, the patient immediately developed an acute pulmonary edema with severe clinical deterioration, which required assistance with extracorporeal membrane oxygenation for recovery. Copyright © 2014 Asociación Española de Pediatría. Published by Elsevier Espana. All rights reserved.

  7. Differential aspects between cobalt-chromium everolimus drug-eluting stent and Absorb everolimus bioresorbable vascular scaffold: from bench to clinical use.

    Science.gov (United States)

    Sotomi, Yohei; Suwannasom, Pannipa; Tenekecioglu, Erhan; Tateishi, Hiroki; Abdelghani, Mohammad; Serruys, Patrick W; Onuma, Yoshinobu

    2015-10-01

    Drug-eluting stents have significantly improved the outcomes of percutaneous coronary intervention by substantially reducing in-stent restenosis and stent thrombosis. However, a potential limitation of these stents is the permanent presence of a metallic foreign body within the artery, which may cause vascular inflammation, restenosis, thrombosis, neoatherosclerosis, permanent impairment of the physiological vasomotor function and interference with potential future grafting of the stented segment. Bioresorbable scaffolds have the potential to overcome these limitations as they provide temporary scaffolding and then disappear, liberating the treated vessel from its cage and restoring pulsatility, cyclical strain, physiological shear stress and mechanotransduction. This article presents a comparison between the most widespread bioresorbable vascular scaffold 'Absorb BVS' and second-generation drug-eluting stent (cobalt chromium everolimus-eluting stent) from bench to clinical use.

  8. Improving hemocompatibility and accelerating endothelialization of vascular stents by a copper-titanium film.

    Science.gov (United States)

    Liu, Hengquan; Pan, Changjiang; Zhou, Shijie; Li, Junfeng; Huang, Nan; Dong, Lihua

    2016-12-01

    Bio-inorganic films and drug-eluting coatings are usually used to improve the hemocompatibility and inhibit restenosis of vascular stent; however, above bio-performances couldn't combine together with single materials. In the present study, we reported a simple approach to fabricate a metal film with the aim of imparting the stent with good blood compatibility and accelerating endothelialization. The films with various ratios of Cu and Ti were prepared through the physical vapor deposition. Phase structure and element composition were investigated by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS), respectively. The releasing volume of copper ion in Cu/Ti film was determined by immersing test. The hemolysis ratio, platelet adhesion and clotting time were applied to evaluate the hemocompatibility. The proliferative behaviors of endothelial cells and smooth muscle cells under certain copper concentration were investigated in vitro and in vivo. Results indicated that copper-titanium films exhibited good hemocompatibility in vitro; however, the increase of Cu/Ti ratio could lead to increasing hemolysis ratio. Endothelial cells displayed more proliferative than smooth muscle cells when the copper concentration was copper concentration was increased. The complete endothelialization of the film with low copper in vivo was observed at the 2nd week, indicating that the copper-titanium film with the lower copper concentration could promote endothelialization. Therefore, the inorganic copper-titanium film could be potential biomaterials to improve blood compatibility and accelerating endothelialization of vascular stents. Copyright © 2016 Elsevier B.V. All rights reserved.

  9. Distinctive effects of CD34- and CD133-specific antibody-coated stents on re-endothelialization and in-stent restenosis at the early phase of vascular injury

    DEFF Research Database (Denmark)

    Wu, Xue; Yin, Tieying; Tian, Jie

    2015-01-01

    It is not clear what effects of CD34- and CD133-specific antibody-coated stents have on re-endothelialization and in-stent restenosis (ISR) at the early phase of vascular injury. This study aims at determining the capabilities of different coatings on stents (e.g. gelatin, anti-CD133 and anti-CD34...... experiment using a rabbit model in which the coated stents with different substrates were implanted showed that anti-CD34 and anti-CD133 antibody-coated stents markedly reduced the intima area and restenosis than bare mental stents (BMS) and gelatin-coated stents. Compared with the anti-CD34 antibody...... for capturing EPCs is better than anti-CD34 antibody in promoting endothelialization and reducing ISR....

  10. Why Vascular Surgeons and Interventional Radiologists Collaborate or Compete: A Look at Endovascular Stent Placements

    Energy Technology Data Exchange (ETDEWEB)

    Keller, Eric J.; Collins, Jeremy D. [Northwestern University Feinberg School of Medicine, Department of Radiology (United States); Crowley-Matoka, Megan [Northwestern University Feinberg School of Medicine, Center for Bioethics and Medical Humanities (United States); Chrisman, Howard B. [Northwestern University Feinberg School of Medicine, Department of Radiology (United States); Milad, Magdy P. [Northwestern University Feinberg School of Medicine, Department of Obstetrics and Gynecology-Reproductive Endocrinology and Infertility (United States); Vogelzang, Robert L., E-mail: vogelzang@northwestern.edu [Northwestern University Feinberg School of Medicine, Department of Radiology (United States)

    2017-06-15

    PurposeTo understand how cultural differences between vascular surgeons (VSs) and interventional radiologists (IRs) affect their clinical decision making and inter-specialty relationships.MethodsTwenty-four conversational interviews were conducted with IRs and VSs about their approaches to patient care, views of their specialty and others, and solutions to any expressed concerns. Interview transcripts were systematically analyzed to identify and compare key themes according to the constructivist grounded theory and content analysis using NVivo 10 software. These data were supplemented with a retrospective analysis of 3658 endovascular stent placements performed at a large medical academic center over 11 years. Aggregate counts were divided by provider specialty, and trends were assessed via correlation coefficients.ResultsEndovascular stent placements were relatively equally divided between IR and VS over 11 years with some variability from placements by cardiology. IRs tend to lay claim to treatments as masters of procedures, whereas VSs base their claims on being masters of the treated diseases, leading to collaboration in some practices and bitter competition in others. The level of perceived competition was most associated with specialists’ awareness of and appreciation for specialty-specific values rather than differences in practice structure/reimbursement.ConclusionsUnderstanding cultural differences between IRs and VSs is imperative for fostering better collaboration to grow shared territory rather than competing for the same slice of the pie.

  11. Hydrophilic surface modification of polymer vascular prostheses and metal endoluminal stents

    Science.gov (United States)

    Amery, Drew Powell

    1997-12-01

    Large diameter vascular replacements of GORE-TEXsp°ler or Dacronsp°ler are frequently used to replace damaged arteries. Poor long term patency of small diameter grafts, 6 millimeters or less, is attributed to platelet adhesion and the inability to regenerate a blood contacting surface of vascular endothelium. Metal endoluminal stents are vascular prostheses used to keep arterial lumens open following angioplasty. Complications for these implants include short term thrombogenicity and long term restenosis. This study was directed to the synthesis and characterization of more biocompatible surfaces for these devices. Gamma radiation induced-graft polymerization and radio frequency plasma activation was investigated to surface modify polymethyl methacrylate (PMMA), polyethylene terephthalate (PET), expanded polytetrafluoroethylene (ePTFE), and 316 stainless steel. To mimic natural biocompatible tissue surfacesl a series of hydrophilic polymers were grafted onto PMMA, PET, and ePTFE. Hydrophilic graft polymers were derived from N-vinyl pyrrolidone (NVP), potassium sulfopropylacrylate (KSPA), and dimethylacrylamide, and were grafted copolymerized with several bioactive compounds in a two step modification process. Complex graft surfaces containing fibronectin (Fn), laminin (Lm), type IV collagen (IV), heparin sulfate (Hp), albumin (Alb), and a synthetic fibronectin like protein polymer (RGD) were prepared. For surface modification of endoluminal stents of 316 stainless and tantalum, a combination of RF plasma activation combined with gamma radiation induced grafting was studied. Plasma deposition of hydrophobic poly(hexane) primer layers with water plasma oxidation were examined for initial metal surface activation. Surfaces were characterized by gravimetric analysis, contact angle goniometry, Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), Auger depth proGling, optical microscopy (OM), and low voltage scanning electron

  12. Percutaneous transluminal angioplasty (PTA) and venous stenting in hemodialysis patients with vascular access-related venous stenosis or occlusion

    Energy Technology Data Exchange (ETDEWEB)

    Christidou, Fotini P. [Renal Unit, G.H. ' G. Papanikolaou' , Thessaloniki (Greece); Kalpakidis, Vasilios I. [Department of Radiology, G.H. ' G. Papanikolaou' , Thessaloniki (Greece); Iatrou, Kostas D. [Department of Radiology, G.H. ' G. Papanikolaou' , Thessaloniki (Greece); Zervidis, Ioannis A. [Department of Radiology, G.H. ' G. Papanikolaou' , Thessaloniki (Greece); Bamichas, Gerasimos I. [Renal Unit, G.H. ' G. Papanikolaou' , Thessaloniki (Greece); Gionanlis, Lazaros C. [Renal Unit, G.H. ' G. Papanikolaou' , Thessaloniki (Greece); Natse, Taisir A. [Renal Unit, G.H. ' G. Papanikolaou' , Thessaloniki (Greece); Sombolos, Kostas J. [Renal Unit, G.H. ' G. Papanikolaou' , Thessaloniki (Greece)]. E-mail: sobolos@spark.net.gr

    2006-05-15

    Aim of the study: To present our experience with PTA and venous stenting in hemodialysis patients with vascular access (VA) related venous stenosis or occlusion. Patients - methods: We studied retrospectively 22 hemodialysis patients with VA-related venous stenosis or occlusions that were treated with PTA and subsequent stenting. The following lesions were detected by digital subtraction venography: occlusion of the brachiocephalic and/or subclavian veins in four patients, stenosis (80-90%) of the same veins in 10 patients, stenosis (80-95%) of the axillary vein in four patients, brachial vein stenosis in two patients, and cephalic vein stenosis in two patients. The follow-up period ranged from 3 to 29 months (mean 15.4 {+-} 9.8 months). Primary and cumulative stent patency was recorded. Results: Twenty-two primary venous PTA-stent implantation procedures were performed using 25 stents. The initial deployment of these 25 stents was technically successful, with complete opening (>80%) of the vein's lumen in all but one patient (95.4%). The patency of the vein immediately after the stenting procedure was greater than 90% in 13 patients, 80-90% in eight patients, and less than 40% in the case involving failure. Seventeen episodes of re-obstruction occurred in 13 patients (59%), and all were treated with the same PTA-stent procedures. At the end of the study period 47 stents had been placed in patients. The 3, 6, 12 and 24-month primary patency rates were 88.3%, 65.3%, 45.6% and 25.5%, respectively. Overall cumulative stent patency was 95.4% after 3 months, 79% after 6 months, 74% after 12 months, and 62.8% after 24 months. Conclusion: PTA with primary venous stenting is an effective method for the treatment of VA-related stenosis or occlusion. However, repeat and sometimes multiple interventions are usually needed for the treatment of re-stenosis or re-occlusion episodes.

  13. Simultaneous dual vascular access site for the treatment of coronary artery bifurcation lesions by complex 2-stent technique.

    Science.gov (United States)

    Isaaz, Karl; Mayaud, Norbert; Lamaud, Michel; Raynaud, Amélie; Cerisier, Alexis; Sabry, Mohammed Hassan; Richard, Laure; Khamis, Hazem; Abd-Alaziz, Ahmad; DA Costa, Antoine

    2012-10-01

    To propose an original approach based on simultaneous dual vascular access site (DAS) using 2 small-size guiding catheters to easily perform complex 2-stent techniques for bifurcation coronary lesions (BL). Simultaneous kissing stenting and classic crush technique require large 7 or 8Fr guiding catheters leading to large amounts of contrast medium, vascular access site complications, and sometimes frictions or criss-cross of the 2-stent delivery systems. DAS was used in 30 patients with BL (11 radio-radial, 16 radio-femoral, and 3 femoro-femoral). Among 60 guiding catheters, the size was 5Fr in 28, 6Fr in 30, and 7Fr in 2 cases of double adjacent BL. When 2 different size catheters were used, contrast medium injections were done using the smallest size catheter. DAS patients were compared with a group of 30 BL patients treated using a single femoral vascular access site (SAS) with 7 or 8Fr catheters. Success rate was 100% in all patients. Contrast volume used was smaller in DAS than in SAS patients (277 ± 156 cc vs. 380 ± 165 cc,P = 0.01). No vascular access site complication occurred in the sub-group of the 11 DAS radio-radial patients. Postintervention hospitalization duration was shorter in DAS than in SAS (1.9 ± 2 vs. 2.8 ± 2 days,P = 0.048). DAS allows to successfully perform complex stenting technique of BL using small-size guiding catheters leading to decreased contrast medium volume, decreased vascular access site complications rates, and shortened hospitalization duration. ©2012, Wiley Periodicals, Inc.

  14. Treatment of a Coronary Bifurcation Lesion Using One Dedicated Sirolimus Eluting Bifurcation Stent in Combination with a Bioresorbable Vascular Scaffold: A Novel Option for Coronary Bifurcation Approach

    Directory of Open Access Journals (Sweden)

    Javier Benezet

    2016-01-01

    Full Text Available We present a complex bifurcation lesion treated with a new two-stent strategy combining a dedicated sirolimus eluting bifurcation stent, BiOSS Lim, with a bioresorbable vascular scaffold (BVS. The advantages of this strategy compared with the conventional two-stent approach are as follows: the dedicated stent protects the carina from being damaged, the large cell at the middle zone of the BiOSS Lim gives possibility to enter easily into the side branch (SB with any standard size conventional device, and, finally, the additional use of BVS in the SB could have a long-term benefit in terms of restenosis.

  15. Direct surface modification of metallic biomaterials via tyrosine oxidation aiming to accelerate the re-endothelialization of vascular stents.

    Science.gov (United States)

    Kakinoki, Sachiro; Takasaki, Kensuke; Mahara, Atsushi; Ehashi, Tomo; Hirano, Yoshiaki; Yamaoka, Tetsuji

    2018-02-01

    Rapid in-situ re-endothelialization of coronary stents is one of the most effective approaches to inhibit late thrombosis and restenosis. Strut surfaces allowing excellent adhesion and migration of endothelial cells and endothelial progenitor cells may accelerate in-situ re-endothelialization. Here, a well-known endothelial cell adhesive peptide, Arg-Glu-Asp-Val (REDV), was directly immobilized onto metallic surfaces by means of single-step tyrosine oxidation with copper chloride (II) and hydrogen peroxide, which we recently reported as a new biomaterial modification technique. REDV immobilization on a 316L stainless steel plate improved endothelial cell adhesion and effectively suppressed platelet adhesion in vitro. In addition, a Co-Cr stent immobilized with Ac-Tyr-Gly-Gly-Gly-Arg-Glu-Asp-Val (Y-REDV) was implanted into a rabbit abdominal aorta. On 7 days postimplantation, 80% of the strut surface of the Y-REDV-immobilized stent was covered by a thin neointimal layer and was similar in appearance to native endothelium. Restenosis and late thrombosis were not observed in the Y-REDV-immobilized stent for 42 days. These findings suggest that direct immobilization of Y-REDV peptide onto metallic biomaterials by tyrosine oxidation is effective for promoting in-situ re-endothelialization in vascular stents. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 491-499, 2018. © 2017 Wiley Periodicals, Inc.

  16. Lean manufacturing and Toyota Production System terminology applied to the procurement of vascular stents in interventional radiology.

    Science.gov (United States)

    de Bucourt, Maximilian; Busse, Reinhard; Güttler, Felix; Wintzer, Christian; Collettini, Federico; Kloeters, Christian; Hamm, Bernd; Teichgräber, Ulf K

    2011-08-01

    OBJECTIVES: To apply the economic terminology of lean manufacturing and the Toyota Production System to the procurement of vascular stents in interventional radiology. METHODS: The economic- and process-driven terminology of lean manufacturing and the Toyota Production System is first presented, including information and product flow as well as value stream mapping (VSM), and then applied to an interdisciplinary setting of physicians, nurses and technicians from different medical departments to identify wastes in the process of endovascular stent procurement in interventional radiology. RESULTS: Using the so-called seven wastes approach of the Toyota Production System (waste of overproducing, waiting, transport, processing, inventory, motion and waste of defects and spoilage) as well as further waste characteristics (gross waste, process and method waste, and micro waste), wastes in the process of endovascular stent procurement in interventional radiology were identified and eliminated to create an overall smoother process from the procurement as well as from the medical perspective. CONCLUSION: Economic terminology of lean manufacturing and the Toyota Production System, especially VSM, can be used to visualise and better understand processes in the procurement of vascular stents in interventional radiology from an economic point of view.

  17. Early vascular healing after titanium-nitride-oxide-coated stent versus platinum-chromium everolimus-eluting stent implantation in patients with acute coronary syndrome.

    Science.gov (United States)

    Varho, Ville; Kiviniemi, Tuomas O; Nammas, Wail; Sia, Jussi; Romppanen, Hannu; Pietilä, Mikko; Airaksinen, Juhani K; Mikkelsson, Jussi; Tuomainen, Petri; Perälä, Anssi; Karjalainen, Pasi P

    2016-07-01

    Data on early vascular healing response of novel stent designs are scarce. In this randomized prospective trial, we sought to compare early neointimal coverage of cobalt-chromium-based titanium-nitride-oxide-coated bioactive stents (CoCr-BAS) versus platinum-chromium everolimus-eluting stents (PtCr-EES) at 2-month follow-up in patients with acute coronary syndrome (ACS). Forty patients with ACS were randomized to receive either CoCr-BAS (n = 19) or PtCr-EES (n = 21). Neointimal strut coverage and strut apposition were examined by optical coherence tomography; and coronary flow reserve (CFR), fractional flow reserve (FFR) and index of microcirculatory resistance (IMR) were assessed using a coronary pressure wire at 2 months. Two patients in the PtCr-EES underwent OCT out of the time frame of the study, and were excluded from analysis. At 63 ± 8 days, 302 cross-sections (3412 struts) were analysed in the CoCr-BAS group, and 324 cross-sections (3460 struts) in the PtCr-EES group. Median [IQR] neointimal thickness was 203 [108] µm and 42.2 [41] µm for CoCr-BAS and PtCr-EES, respectively (p  0.05 for all). CoCr-BAS showed earlier and more adequate neointimal coverage of struts at 2 months, compared with PtCr-EES, but with more neointimal hyperplasia. Functional healing as assessed by CFR, FFR, and IMR was similar between the two stent arms.

  18. Self-expandable vascular stent covered with polyurethane membrane: an experimental preliminary study of a placement in the thoracic descending aorta of a rabbit using endovascular intervention.

    Science.gov (United States)

    Uematsu, M; Okada, M

    2000-04-01

    The effectiveness of self-expandable vascular endoprosthesis covered with polyurethane membrane for arterial substitution was examined in the descending thoracic aorta of a rabbit, followed by an observation period of 937 days. In this model there was no evidence of thrombus, aneurysmal formation, and/or infection. The self-expandable vascular stent covered with a polyurethane membrane showed long-term patency as well as excellent function, and the histological evaluation revealed endothelial cells covering all of the surface of the endoprosthesis, as was expected. Minimal intimal hyperplasia and no calcifica-tion were demonstrated in any portions. This study suggests that our newly designed self-expandable vascular stent covered with a polyurethane membrane could serve as a satisfactory vascular endoprosthesis with a good long-term patency for substitution. Furthermore, stenting using our model is a safe, simple technique, and an effective treatment for vascular remodeling.

  19. Investigation Of Interaction Between Nitinol Stent And A Vascular Plaque Using Finite Element Method

    Directory of Open Access Journals (Sweden)

    Recep Güneş

    2012-06-01

    Full Text Available In this study, the interaction between the Nitinol stent and the artery with plaque was investigated using finite element method. The occurring pressure values during the cardiac contraction (systolic and loosening (diastolic were applied as loading to the modeled system with Nitinol stent. In the light of the stress values, the suitability of the Nitinol stent in an artery with plaque was investigated. In the analysis, Nitinol stent was assumed to be shape memory alloy, and artery and plaque were assumed to behave linearly elastic. As a result, the stress and deformations in the plaque and artery due to the interference of Nitinol stent were discussed and concluded that the structure of artery with plaque can be expanded in accordance with Nitinol stent.

  20. A Zr-based bulk metallic glass for future stent applications: Materials properties, finite element modeling, and in vitro human vascular cell response.

    Science.gov (United States)

    Huang, Lu; Pu, Chao; Fisher, Richard K; Mountain, Deidra J H; Gao, Yanfei; Liaw, Peter K; Zhang, Wei; He, Wei

    2015-10-01

    Despite the prevalent use of crystalline alloys in current vascular stent technology, new biomaterials are being actively sought after to improve stent performance. In this study, we demonstrated the potential of a Zr-Al-Fe-Cu bulk metallic glass (BMG) to serve as a candidate stent material. The mechanical properties of the Zr-based BMG, determined under both static and cyclic loadings, were characterized by high strength, which would allow for the design of thinner stent struts to improve stent biocompatibility. Finite element analysis further complemented the experimental results and revealed that a stent made of the Zr-based BMG was more compliant with the beats of a blood vessel, compared with medical 316L stainless steel. The Zr-based BMG was found to be corrosion resistant in a simulated body environment, owing to the presence of a highly stable ZrO2-rich surface passive film. Application-specific biocompatibility studies were conducted using human aortic endothelial cells and smooth muscle cells. The Zr-Al-Fe-Cu BMG was found to support stronger adhesion and faster coverage of endothelial cells and slower growth of smooth muscle cells than 316L stainless steel. These results suggest that the Zr-based BMG could promote re-endothelialization and potentially lower the risk of restenosis, which are critical to improve vascular stent implantation integration. In general, findings in this study raised the curtain for the potential application of BMGs as future candidates for stent applications. Vascular stents are medical devices typically used to restore the lumen of narrowed or clogged blood vessel. Despite the clinical success of metallic materials in stent-assisted angioplasty, post-surgery complications persist due to the mechanical failures, corrosion, and in-stent restenosis of current stents. To overcome these hurdles, strategies including new designs and surface functionalization have been exercised. In addition, the development of new materials with

  1. Express LD vascular stent in the treatment of iliac artery lesions: 24-month results from the MELODIE trial.

    Science.gov (United States)

    Stockx, Luc; Poncyljusz, Wojciech; Krzanowski, Marek; Schroë, Herman; Allocco, Dominic J; Dawkins, Keith D

    2010-10-01

    To report the 2-year results of the MELODIE trial, which evaluated the safety and effectiveness of the balloon-expandable Express LD Vascular stent for the treatment of atherosclerotic iliac artery disease. This prospective, multicenter, single-arm trial enrolled 151 patients (113 men; mean age 60.1±8.4 years) with 163 de novo or restenotic iliac lesions. The primary endpoint, 6-month angiographic mean percent loss of luminal diameter, was compared to an objective performance criterion (OPC) based on published results with the Palmaz stent. Follow-up included ankle-brachial index (ABI) measurement and symptom assessment (Fontaine classification) at discharge, 30 days, and 6, 12, and 24 months. Arteriography was performed at 6 months and computed tomographic angiography (CTA) at 1 and 2 years. The primary endpoint of 6-month mean percent luminal diameter loss was 16.2% (upper 95% confidence boundary of 19.1%) and non-inferior to the 20% OPC (p = 0.006). Primary patency was 92.1% at 6 months and 87.8% at 2 years. The rate of major adverse events (MAE) was 6.3% at 6 months and 10.2% at 2 years. Of the 3 event types included in the definition of MAE, only target lesion revascularization occurred; no distal embolization or device- or procedure-related deaths were recorded. The percent of patients with Fontaine stage IIb symptoms or worse improved from 84.1% before the procedure to 16.8% at 2 years (p<0.0001). The 2-year ABI remained significantly improved compared to baseline (0.85 versus 0.63, p<0.0001). The Express LD Vascular stent is safe, effective, and non-inferior to the Palmaz stent for treatment of iliac artery stenosis.

  2. Coronary Artery Stent Evaluation Using a Vascular Model at 64-Detector Row CT: Comparison between Prospective and Retrospective ECG-Gated Axial Scans

    Energy Technology Data Exchange (ETDEWEB)

    Suzuki, Shigeru; Furui, Shigeru; Kaminaga, Tatsuro; Miyazawa, Akiyoshi; Ueno, Yasunari; Konno, Kumiko [Teikyo University School of Medicine, Tokyo (Japan); Kuwahara, Sadatoshi; Mehta, Dhruv [Philips Electronics Japan, Ltd. Medical Systems, Tokyo (Japan)

    2009-06-15

    We wanted to evaluate the performance of prospective electrocardiogram (ECG)-gated axial scans for assessing coronary stents as compared with retrospective ECG-gated helical scans. As for a vascular model of the coronary artery, a tube of approximately 2.5-mm inner diameter was adopted and as for stents, three (Bx-Velocity, Express2, and Micro Driver) different kinds of stents were inserted into the tube. Both patent and stenotic models of coronary artery were made by instillating different attenuation (396 vs. 79 Hounsfield unit [HU]) of contrast medium within the tube in tube model. The models were scanned with two types of scan methods with a simulated ECG of 60 beats per minute and using display field of views (FOVs) of 9 and 18 cm. We evaluated the in-stent stenosis visually, and we measured the attenuation values and the diameter of the patent stent lumen. The visualization of the stent lumen of the vascular models was improved with using the prospective ECG-gated axial scans and a 9-cm FOV. The inner diameters of the vascular models were underestimated with mean measurement errors of -1.10 to -1.36 mm. The measurement errors were smaller with using the prospective ECG-gated axial scans (Bx-Velocity and Express2, p < 0.0001; Micro Driver, p = 0.0004) and a 9-cm FOV (all stents: p < 0.0001), as compared with the other conditions, respectively. The luminal attenuation value was overestimated in each condition. For the luminal attenuation measurement, the use of prospective ECG-gated axial scans provided less measurement error compared with the retrospective ECG-gated helical scans (all stents: p < 0.0001), and the use of a 9-cm FOV tended to decrease the measurement error. The visualization of coronary stents is improved by the use of prospective ECG-gated axial scans and using a small FOV with reduced blooming artifacts and increased spatial resolution.

  3. In vitro performance investigation of bioresorbable scaffolds – Standard tests for vascular stents and beyond

    Energy Technology Data Exchange (ETDEWEB)

    Schmidt, Wolfram, E-mail: wolfram.schmidt@uni-rostock.de [Institute for Biomedical Engineering, University Medicine Rostock, Friedrich-Barnewitz-Strasse 4, D-18119 Rostock-Warnemünde (Germany); Behrens, Peter, E-mail: peter.behrens@uni-rostock.de [Institute for Biomedical Engineering, University Medicine Rostock, Friedrich-Barnewitz-Strasse 4, D-18119 Rostock-Warnemünde (Germany); Brandt-Wunderlich, Christoph, E-mail: christoph.brandt@uni-rostock.de [Institute for ImplantTechnology and Biomaterials – IIB e.V., Associated Institute of the University of Rostock, Friedrich-Barnewitz-Strasse 4, D-18119 Rostock-Warnemünde (Germany); Siewert, Stefan, E-mail: stefan.siewert@uni-rostock.de [Institute for ImplantTechnology and Biomaterials – IIB e.V., Associated Institute of the University of Rostock, Friedrich-Barnewitz-Strasse 4, D-18119 Rostock-Warnemünde (Germany); Grabow, Niels, E-mail: niels.grabow@uni-rostock.de [Institute for Biomedical Engineering, University Medicine Rostock, Friedrich-Barnewitz-Strasse 4, D-18119 Rostock-Warnemünde (Germany); Schmitz, Klaus-Peter, E-mail: klaus-peter.schmitz@uni-rostock.de [Institute for ImplantTechnology and Biomaterials – IIB e.V., Associated Institute of the University of Rostock, Friedrich-Barnewitz-Strasse 4, D-18119 Rostock-Warnemünde (Germany)

    2016-09-15

    Background/Purpose: Biodegradable polymers are the main materials for coronary scaffolds. Magnesium has been investigated as a potential alternative and was successfully tested in human clinical trials. However, it is still challenging to achieve mechanical parameters comparative to permanent bare metal (BMS) and drug-eluting stents (DES). As such, in vitro tests are required to assess mechanical parameters correlated to the safety and efficacy of the device. Methods/Materials: In vitro bench tests evaluate scaffold profiles, length, deliverability, expansion behavior including acute elastic and time-dependent recoil, bending stiffness and radial strength. The Absorb GT1 (Abbott Vascular, Temecula, CA), DESolve (Elixir Medical Corporation, Sunnyvale, CA) and the Magmaris (BIOTRONIK AG, Bülach, Switzerland) that was previously tested in the BIOSOLVE II study, were tested. Results: Crimped profiles were 1.38 ± 0.01 mm (Absorb GT1), 1.39 ± 0.01 mm (DESolve) and 1.44 ± 0.00 mm (Magmaris) enabling 6F compatibility. Trackability was measured depending on stiffness and force transmission (pushability). Acute elastic recoil was measured at free expansion and within a mock vessel, respectively, yielding results of 5.86 ± 0.76 and 5.22 ± 0.38% (Absorb), 7.85 ± 3.45 and 9.42 ± 0.21% (DESolve) and 5.57 ± 0.72 and 4.94 ± 0.31% (Magmaris). Time-dependent recoil (after 1 h) was observed for the Absorb and DESolve scaffolds but not for the Magmaris. The self-correcting wall apposition behavior of the DESolve did not prevent time-dependent recoil under vessel loading. Conclusions: The results of the suggested test methods allow assessment of technical feasibility based on objective mechanical data and highlight the main differences between polymeric and metallic bioresorbable scaffolds.

  4. Vascular Biocompatibility of a Triple Layered Self Expanding Stent-Graft in a Dog Mode

    Energy Technology Data Exchange (ETDEWEB)

    Bae, Jae Ik; Won, Je Hwan; Jang, Eun Ho; Lee, Sung Yeong; Ko, Kwang Tae [Dept. of Radiology, Ajou University School of Medicine, Suwon (Korea, Republic of); Jin, Bo Hwan [Medical Science Research Center, Ajou University School of Medicine, Suwon (Korea, Republic of); Lee, June Woo [Dept. of Radiology, Busan National University College of Medicine, Busan (Korea, Republic of)

    2012-02-15

    To evaluate performance and biocompatibility of a newly designed self-expanding stent graft, which consisted of two nitinol stents and an intervening expanded polytetrafluoroethylene membrane in a dog artery model. Twelve stent grafts were placed in the aorta of 6 dogs (beagle, mean body weight 11 kg) for 4 weeks (n = 4) and 12 weeks (n = 8). Luminal diameters were measured for each segment (the proximal bare, the middle graft, the distal bare) by angiographies after implantation and follow up periods. Percent luminal stenosis based on angiographies, histomorphometric, histologic, and scanning electron microscopic analyses of each segments were performed. Blood flow through the stent grafts was good after implantation and during the follow up period, without thrombotic occlusion or stent graft migration. The mean percent luminal stenosis of the proximal bare, the middle grafted and the distal bare segments after 12 weeks were 13.5%, 3.9%, 9.6% retrospectively. The mean neointimal areas of the middle grafted segment were 4.39 mm{sup 2} (4 week) and 4.92 mm{sup 2} (12 week). Mature endothelialization was evident in over 70% of the area of the stented artery after 4 weeks and in over 90% after 12 weeks. The stent graft was well placed in the attempted area without migration. During the 12-week-follow up period, it showed a good patency without thrombotic occlusion or significant in-stent luminal stenosis. Endothelialization was rapid and nearly complete. Neointima was thin and smooth on the middle graft segment and thicker and irregular on the bare segments.

  5. Bioresorbable vascular scaffold (BVS) for in-stent chronic total occlusion: Antegrade recanalization and IVUS-guided BVS implantation by radial access

    Energy Technology Data Exchange (ETDEWEB)

    Medda, Massimo [Interventional Cardiology Unit, Istituto Clinico Sant' Ambrogio, Milano (Italy); Casilli, Francesco, E-mail: frcasill@tin.it [Interventional Cardiology Unit, Istituto Clinico Sant' Ambrogio, Milano (Italy); Bande, Marta [Interventional Cardiology Unit, Istituto Clinico Sant' Ambrogio, Milano (Italy); Latini, Maria Giulia [Cardiologia Interventistica, IRCCS Policlinico San Donato, San Donato Milanese, Milano (Italy); Ghommidh, Mehdi [Interventional Cardiology Unit, Istituto Clinico Sant' Ambrogio, Milano (Italy); Del Furia, Francesca [Unità Operativa di Cardiologia, Azienda Ospedaliera di Melegnano, Milano (Italy); Inglese, Luigi [Interventistica Cardiovascolare, Gruppo Sanitario Policlinico di Monza, Milano (Italy)

    2016-01-15

    The completely absorbable stents represent one of the latest innovations in the field of interventional cardiology, prospecting the possibility of “vascular repair”. In the published trials (ABSORB Cohort A and B, ABSORB EXTEND, and ABSORB II, III and IV) chronic total occlusions (CTOs) were considered an exclusion criteria. More recently the CTO-ABSORB pilot study demonstrated the safety and feasibility of bioresorbable vascular scaffold (BVS) use in case of CTO recanalization. We present the first case, to our knowledge, of in-stent occlusion successfully treated with an everolimus-eluting BVS and discuss its potential advantages in such kind of lesions.

  6. The behavior of vascular smooth muscle cells and platelets onto epigallocatechin gallate-releasing poly(l-lactide-co-epsilon-caprolactone) as stent-coating materials.

    Science.gov (United States)

    Cho, Han Hee; Han, Dong-Wook; Matsumura, Kazuaki; Tsutsumi, Sadami; Hyon, Suong-Hyu

    2008-03-01

    Localized drug delivery from drug-eluting stents has been accepted as one of the most promising treatment methods for preventing restenosis after stenting. However, thrombosis, inflammation, and restenosis are still major problems for the utility of cardiovascular prostheses such as vascular grafts and stents. Epigallocatechin-3-O-gallate (EGCG), a major polyphenolic constituent of green tea, has been shown to have anti-thrombotic, anti-inflammatory and anti-proliferative activities. It was hypothesized that controlled release of EGCG from biodegradable poly(lactide-co-epsilon-caprolactone, PLCL) stent coatings would suppress migration and invasion of vascular smooth muscle cells (VSMCs) as well as platelet-mediated thrombosis. EGCG-releasing PLCL (E-PLCL) was prepared by blending PLCL with 5% EGCG. The surface morphology, roughness and melting temperature of PLCL were not changed despite EGCG addition. EGCG did, however, EGCG appreciably increase the hydrophilicity of PLCL. EGCG was found to be uniformly dispersed throughout E-PLCL without direct chemical interactions with PLCL. E-PLCL displayed diffusion controlled release of EGCG release for periods up to 34 days. E-PLCL significantly suppressed the migration and invasion of VSMCs as well as the adhesion and activation of platelets. E-PLCL coatings were able to smooth the surface of bare stents with neither cracks nor webbings after balloon expansion. The structural integrity of coatings was sufficient to resist delamination or destruction during 90% dilatation. These results suggest that EGCG-releasing polymers can be effectively applied for fabricating an EGCG-eluting vascular stent to prevent in-stent restenosis and thrombosis.

  7. A precious metal alloy for construction of MR imaging-compatible balloon-expandable vascular stents

    NARCIS (Netherlands)

    L.C. van Dijk (Lukas); J. van Holten; B.P. van Dijk (Bastiaan); N.A. Matheijssen; P.M.T. Pattynama (Peter)

    2001-01-01

    textabstractThe authors developed ABI alloy, which mechanically resembles stainless steel 316. The main elements of ABI alloy are palladium and silver. Magnetic resonance (MR) images and radiographs of ABI alloy and stainless steel 316 stent models and of nitinol, tantalum, and

  8. Gender-specific 30-day outcomes after carotid endarterectomy and carotid artery stenting in the Society for Vascular Surgery Vascular Registry.

    Science.gov (United States)

    Jim, Jeffrey; Dillavou, Ellen D; Upchurch, Gilbert R; Osborne, Nicholas H; Kenwood, Christopher T; Siami, Flora S; White, Rodney A; Ricotta, Joseph J

    2014-03-01

    Although the optimal treatment of carotid stenosis remains unclear, available data suggest that women have higher risk of adverse events after carotid revascularization. We used data from the Society for Vascular Surgery Vascular Registry to determine the effect of gender on outcomes after carotid endarterectomy (CEA) and carotid artery stenting (CAS). There were 9865 patients (40.6% women) who underwent CEA (n = 6492) and CAS (n = 3373). The primary end point was a composite of death, stroke, and myocardial infarction at 30 days. There was no difference in age and ethnicity between genders, but men were more likely to be symptomatic (41.6% vs 38.6%; P gender, there were no statistically significant differences in the primary end point for CEA (women, 4.07%; men, 4.06%) or CAS (women, 6.69%; men, 6.80%). There remains no difference after stratification by symptomatology and multivariate risk adjustment. In this large, real-world analysis, women and men demonstrated similar results after CEA or CAS. These data suggest that, contrary to previous reports, women do not have a higher risk of adverse events after carotid revascularization. Copyright © 2014 Society for Vascular Surgery. Published by Mosby, Inc. All rights reserved.

  9. MRI-compatible Nb–60Ta–2Zr alloy used for vascular stents: Haemocompatibility and its correlation with protein adsorption

    Energy Technology Data Exchange (ETDEWEB)

    Li, Xiu-Mei [School of Stomatology, China Medical University, 117 Nanjing North Street, Shenyang 110002 (China); Li, Hui-Zhe; Wang, Shao-Ping [Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, 72 Wenhua Road, Shenyang 110016 (China); Huang, Hsun-Miao; Huang, Her-Hsiung [Biomaterials and Electrochemistry Lab, Department of Dentistry, National Yang-Ming University, Taipei City 112, Taiwan (China); Ai, Hong-Jun, E-mail: aih0620@yahoo.com.cn [School of Stomatology, China Medical University, 117 Nanjing North Street, Shenyang 110002 (China); Xu, Jian, E-mail: jianxu@imr.ac.cn [Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, 72 Wenhua Road, Shenyang 110016 (China)

    2014-09-01

    Nb–60Ta–2Zr is a newly developed MRI-compatible alloy used for vascular stents. In this work, its haemocompatibility was investigated, including platelet adhesion (lactate dehydrogenase activity), platelet activation (P-selectin expression), coagulation and haemolysis. For comparison, parallel assessments for these factors were performed for the niobium, tantalum, 316L stainless steel (316L SS) and L605 Co–Cr alloy (L605). In addition, albumin and fibrinogen were selected to examine the correlation of protein adsorption with platelet adhesion and metal surface properties. The propensity for platelet adhesion and activation on the Nb–60Ta–2Zr alloy was at nearly the same level as that for Nb and Ta but was slightly less than those of 316L SS and L605. The mitigated platelet adhesion and activation of the Nb–60Ta–2Zr alloy is associated with its decreased adsorption of fibrinogen. The Nb–60Ta–2Zr alloy has a longer clotting time and exhibits significantly superior thromboresistance than 316L SS and L605. Moreover, the haemolysis rate of the Nb–60Ta–2Zr alloy satisfies the bio-safety requirement of the ISO 10993–4 standard. The favourable haemocompatiblity of the Nb–60Ta–2Zr alloy provides evidence of its good biocompatibility and of its suitability as a candidate stent material. - Highlights: • The Nb–60Ta–2Zr alloy is less hydrophobic than the 316L SS and L605 alloy. • The Nb–60Ta–2Zr has slightly weak propensity for platelet adhesion and activation. • The Nb–60Ta–2Zr alloy results in a longer clotting time. • Haemolysis of Nb–60Ta–2Zr is slightly lower than that of 316L SS and L605. • The Nb–60Ta–2Zr alloy is a promising MRI-compatible stent material.

  10. Comparison of Direct Site Endovascular Repair Utilizing Expandable PTFE Stent Grafts Vs. Standard Vascular Shunts in a Porcine (Sus Scrofa) Model.

    Science.gov (United States)

    Davidson, Anders J; Neff, Lucas P; Grayson, J Kevin; Clement, Nathan F; DeSoucy, Erik S; Simon-Logan, Meryl A; Abbot, Christopher M; Sampson, James B; Williams, Timothy K

    2017-07-08

    The small diameter of temporary vascular shunts for vascular trauma management may restrict flow and result in ischemia or early thrombosis. We have previously reported a clinical experience with direct, open surgical reconstruction using expanded polytetrafluoroethylene (ePTFE) stent grafts to create a "sutureless" anastomosis as an alternative to standard temporary vascular shunts. We sought to characterize patency and flow characteristics of these grafts compared to standard shunts in a survival model of porcine vascular injury. 12 Yorkshire-cross swine received a 2cm long near-circumferential defect in the bilateral iliac arteries. A14-French Argyle shunt was inserted into one randomly assigned artery, with a self-expanding ePTFE stent deployed in the other. At 72 hours, conduit patency was evaluated by angiography. Arterial flow measurements were obtained at baseline, immediately after intervention, and after 72 hours via direct measurement with perivascular flow meters. Blood pressure proximal and distal to the conduits and arterial samples for histopathology were obtained during the terminal procedure. Angiography revealed no difference in patency at 72 hours (P=1.0). While there was no difference in baseline arterial flow between arteries (P=0.63), the stent grafts demonstrated significantly improved blood flow compared to shunts both immediately after intervention (390±36mL/min vs 265±25mL/min, p=0.002) and at 72 hours (261±29mL/min vs 170±36mL/min, p=0.005). The pressure gradient across the shunts was greater than that of the stent grafts (11.5mmHg IQR[3-19] vs. 3mmHg IQR[3-5], p=0.013). The speed of deployment was similar between the two devices. Open "sutureless" direct site repair using commercially available stent grafts to treat vascular injury is a technically feasible strategy for damage control management of peripheral vascular injury and offers increased blood flow when compared to temporary shunts. Furthermore, stent grafts may offer

  11. Comparison of direct site endovascular repair utilizing expandable polytetrafluoroethylene stent grafts versus standard vascular shunts in a porcine (Sus scrofa) model.

    Science.gov (United States)

    Davidson, Anders J; Neff, Lucas P; Grayson, J Kevin; Clement, Nathan F; DeSoucy, Erik S; Simon Logan, Meryl A; Abbot, Christopher M; Sampson, James B; Williams, Timothy K

    2017-09-01

    The small diameter of temporary vascular shunts for vascular trauma management may restrict flow and result in ischemia or early thrombosis. We have previously reported a clinical experience with direct, open surgical reconstruction using expandable polytetrafluoroethylene stent grafts to create a "sutureless" anastomosis as an alternative to standard temporary vascular shunts. We sought to characterize patency and flow characteristics of these grafts compared with standard shunts in a survival model of porcine vascular injury. Twelve Yorkshire-cross swine received a 2-cm-long near-circumferential defect in the bilateral iliac arteries. A 14 Fr Argyle shunt was inserted into one randomly assigned artery, with a self-expanding expandable polytetrafluoroethylene stent deployed in the other. At 72 hours, conduit patency was evaluated by angiography. Arterial flow measurements were obtained at baseline, immediately after intervention, and after 72 hours via direct measurement with perivascular flow meters. Blood pressure proximal and distal to the conduits and arterial samples for histopathology were obtained during the terminal procedure. Angiography revealed no difference in patency at 72 hours (p = 1.0). While there was no difference in baseline arterial flow between arteries (p = 0.63), the stent grafts demonstrated significantly improved blood flow compared with shunts both immediately after intervention (390 ± 36 mL/min vs. 265 ± 25 mL/min, p = 0.002) and at 72 hours (261 ± 29 mL/min vs. 170 ± 36 mL/min, p = 0.005). The pressure gradient across the shunts was greater than that of the stent grafts (11.5 mm Hg [interquartile range, 3-19 mm Hg] vs. 3 mm Hg [interquartile range, 3-5 mm Hg], p = 0.013). The speed of deployment was similar between the two devices. Open "sutureless" direct site repair using commercially available stent grafts to treat vascular injury is a technically feasible strategy for damage control management of peripheral vascular injury and

  12. MRI-compatible Nb-60Ta-2Zr alloy for vascular stents: Electrochemical corrosion behavior in simulated plasma solution.

    Science.gov (United States)

    Li, Hui-Zhe; Zhao, Xu; Xu, Jian

    2015-11-01

    Using revised simulated body fluid (r-SBF), the electrochemical corrosion behavior of an Nb-60Ta-2Zr alloy for MRI compatible vascular stents was characterized in vitro. As indicated by XPS analysis, the surface passive oxide film of approximately 1.3nm thickness was identified as a mixture of Nb2O5, Ta2O5 and ZrO2 after immersion in the r-SBF. The Nb-60Ta-2Zr alloy manifests a low corrosion rate and high polarization resistance similar to pure Nb and Ta, as shown by the potentiodynamic polarization curves and EIS. Unlike 316L stainless steel and the L605 Co-Cr alloy, no localized corrosion has been detected. Semiconducting property of passive film on the Nb-60Ta-2Zr alloy was identified as the n-type, with growth mechanism of high-field controlled growth. The excellent corrosion resistance in simulated human blood enviroment renders the Nb-60Ta-2Zr alloy promising as stent candidate material. Copyright © 2015 Elsevier B.V. All rights reserved.

  13. MRI-compatible Nb-60Ta-2Zr alloy used for vascular stents: haemocompatibility and its correlation with protein adsorption.

    Science.gov (United States)

    Li, Xiu-Mei; Li, Hui-Zhe; Wang, Shao-Ping; Huang, Hsun-Miao; Huang, Her-Hsiung; Ai, Hong-Jun; Xu, Jian

    2014-09-01

    Nb-60Ta-2Zr is a newly developed MRI-compatible alloy used for vascular stents. In this work, its haemocompatibility was investigated, including platelet adhesion (lactate dehydrogenase activity), platelet activation (P-selectin expression), coagulation and haemolysis. For comparison, parallel assessments for these factors were performed for the niobium, tantalum, 316L stainless steel (316L SS) and L605 Co-Cr alloy (L605). In addition, albumin and fibrinogen were selected to examine the correlation of protein adsorption with platelet adhesion and metal surface properties. The propensity for platelet adhesion and activation on the Nb-60Ta-2Zr alloy was at nearly the same level as that for Nb and Ta but was slightly less than those of 316L SS and L605. The mitigated platelet adhesion and activation of the Nb-60Ta-2Zr alloy is associated with its decreased adsorption of fibrinogen. The Nb-60Ta-2Zr alloy has a longer clotting time and exhibits significantly superior thromboresistance than 316L SS and L605. Moreover, the haemolysis rate of the Nb-60Ta-2Zr alloy satisfies the bio-safety requirement of the ISO 10993-4 standard. The favourable haemocompatiblity of the Nb-60Ta-2Zr alloy provides evidence of its good biocompatibility and of its suitability as a candidate stent material. Copyright © 2014 Elsevier B.V. All rights reserved.

  14. Bioabsorbable drug-eluting vascular scaffold for the treatment of coronary in-stent restenosis: A two center registry

    Energy Technology Data Exchange (ETDEWEB)

    Moscarella, Elisabetta [Division of Cardiology, Seconda Università degli studi di Napoli, AO Dei cColli, PO Monaldi (Italy); Varricchio, Attilio [Division of Cardiology, Department of Advanced Biomedical Sciences, University of Napoli “Federico II”, Napoli (Italy); Stabile, Eugenio, E-mail: geko50@hotmail.com [Laboratory of Invasive Cardiology, Dipartimento di Cardiologia, Presidio Ospedaliero “Monaldi”, Azienda Ospedaliera “Dei Colli”, Napoli (Italy); Franzone, Anna [Laboratory of Invasive Cardiology, Dipartimento di Cardiologia, Presidio Ospedaliero “Monaldi”, Azienda Ospedaliera “Dei Colli”, Napoli (Italy); Granata, Francesco [Division of Cardiology, Seconda Università degli studi di Napoli, AO Dei cColli, PO Monaldi (Italy); Rapacciuolo, Antonio; Galasso, Gennaro [Laboratory of Invasive Cardiology, Dipartimento di Cardiologia, Presidio Ospedaliero “Monaldi”, Azienda Ospedaliera “Dei Colli”, Napoli (Italy); Capozzolo, Claudia [Division of Cardiology, Department of Advanced Biomedical Sciences, University of Napoli “Federico II”, Napoli (Italy); Cirillo, Plinio [Laboratory of Invasive Cardiology, Dipartimento di Cardiologia, Presidio Ospedaliero “Monaldi”, Azienda Ospedaliera “Dei Colli”, Napoli (Italy); and others

    2015-10-15

    Background/purpose: Coronary in-stent restenosis (ISR) is a clinical problem for which a satisfactory solution has not been found yet. Bioabsorbable drug eluting vascular scaffolds (BVSs) provide transient vessel scaffolding combined with prolonged drug delivery capability. The aim of this study was to investigate the safety of BVS for the treatment of coronary ISR. Methods/materials: Between January 2013 and June 2013, 27 patients (31 lesions), presenting with either stable or unstable angina due to coronary ISR, were enrolled in a single arm, prospective, open label registry. Primary end point was the occurrence of target vessel revascularization (TVR) at 12 months. Secondary end point was the composite of death, myocardial infarction and TVR at 12 months. Results: A diffuse ISR pattern was present in 70% of the lesions; mean lesion length was 34.6 ± 15. BVS was successfully implanted in all patients with no in hospital MACE. At twelve months of follow up, MACE rate was 18.5%. One patient died for non-cardiac reason, one patient died due to a possible stent thrombosis and TVR was necessary in 3 patients (11.1%). Conclusions: Our data suggest that BVS is safe and technically feasible for treatment of long and diffuse coronary ISR. These data could be considered hypothesis generator for a randomized clinical trial. - Highlights: • A safe therapeutic option for the treatment of diffuse ISR; • Technically feasible; • Associated to a low rate of restenosis recurrence at nine month.

  15. Surface characterization of polymer-drug modified vascular stents and intraocular lenses

    Science.gov (United States)

    Elachchabi, Amin

    Two of the most important medical devices in clinical use today are endoluminal stents and intraocular lenses (IOLs). In both devices, surface and interfacial properties are of basic importance in the development and clinical performance of these devices. Drug eluting stents have revolutionized the world of interventional cardiology. Research reported here was devoted to the design and development of new drug eluting stents wherein the metallic backbone is completely embedded in a polymeric matrix used also as a drug reservoir. This design, using silicone-drug compositions can lead to higher drug payloads, less tissue damage during angioplasty balloon/stent expansion, and the novel capability of delivering multiple drugs. The adhesion of the polymeric coating to the metallic stent is essential and has not been adequately reported previously. The adhesion of polydimethylsiloxane (PDMS) coatings to a stainless steel stent substrate was shown to be enhanced by the application of mixtures of tetra-n-propyl silicate, tetrabutyltitanate, tetra-2-methoxyethoxysilane, and 3-(trimethoxysilyl)propyl methacrylate coupling agents. Additionally, the effect of drug loading on the stress/strain properties of the polymeric coating is of basic importance. The tensile strength and percent elongation of dexamethasone loaded PDMS films was shown to remain satisfactory for stent coatings at low concentrations (less than 1%) but decreased as the concentrations of dexamethasone in PDMS was increased to 5%. The release of multiple therapeutic agents from PDMS coatings to reduce in-stent restenosis has not been previously reported. The release profile of Paclitaxel, dexamethasone 21-acetate, and their combination from PDMS coatings was studied using high precision liquid chromatography (HPLC). Although dexamethasone release was reduced by paclitaxel, paclitaxel release was unaffected by combination with dexamethasone. Paclitaxel release from the polymeric matrices was shown to inhibit

  16. Relationship of serum S1P and HC-II levels with vasoactive substances and cytokines in patients with cerebral vascular restenosis after stent implantation

    Directory of Open Access Journals (Sweden)

    Yong Liu

    2017-04-01

    Full Text Available Objective: To study the relationship of serum sphingosine 1-phosphate (S1P and heparin cofactor II (HCII levels with vasoactive substances and cytokines in patients with cerebral vascular restenosis after stent implantation. Methods: 52 patients who received cerebrovascular stent implantation and developed restenosis in our hospital between May 2012 and December 2015 were collected as observation group, and 40 healthy patients with cerebrovascular stent implantation who had re-examination in our hospital during the same period were selected as control group. ELISA method was used to detect serum S1P and HC-II levels as well as vasoactive substance and inflammatory factor contents. Spearman correlation analysis was used to evaluate the relationship of serum S1P and HC-II levels with vasoactive substances and inflammatory factors. Results: Serum S1P and HC-II levels of observation group were lower than those of control group (P<0.05; serum vasoactive substances endothelin (ET, angiotensin II (AngII and thromboxane B2 (TXB2 contents of observation group were higher than those of control group while nitric oxide (NO content was lower than that of control group (P<0.05; serum inflammatory factors hypersensitive C-reactive protein (hs-CRP, interleukin-1 (IL-1, IL-6, IL-8 and IL-11 contents of observation group were higher than those of control group (P<0.05. Serum S1P and HC-II levels in patients with cerebral vascular restenosis after stent implantation were directly correlated with vasoactive substance and inflammatory factor contents. Conclusion: Serum S1P and HC-II levels decrease in patients with cerebral vascular restenosis after stent implantation, and it is an important cause of cerebral vascular dysfunction and systemic inflammatory response.

  17. The value of primary vascular stents in management of early portal vein stenosis after liver transplantation

    Directory of Open Access Journals (Sweden)

    Wen-Tsan Chang

    2016-03-01

    Full Text Available If portal vein stenosis (PVS occurs within 1 month after liver transplantation (LT, especially within 1 week, it can be catastrophic and result in rapid loss of the grafts and mortality. Although surgical treatments have been considered standard treatment for PVS, patients are usually unable to receive operations or re-transplantations, because of their critical conditions and a shortage of grafts. Recently, primary percutaneous transhepatic portal vein stents (PTPS were suggested as alternative and less-invasive treatments of PVS. However, because lethal complications may follow these primary stent placements for patients in early stages after LT, primary PTPS placements for patients suffering PVS 1 month after LT has been suggested. From November 2009 to July 2015, 38 consecutive adult patients underwent LT at our institution. Among them, six recipients suffered PVS within 1 month after LT. Technical success was achieved in all six patients. Clinical success was obtained in two of the four patients suffering PVS within 1 week after LT, and in the other two patients suffering PVS>1 week after LT. All surviving patients and their grafts were in good condition, and their stents remained patent. Our experience showed that primary PTPS placements can be used to effectively treat patients with PVS encountered within 1 month, and even within 1 week, after LT with acceptable short-term results. However, possible fatal complications should be kept in mind. Long-term results of these procedures need further follow-up.

  18. Research on a Zn-Cu alloy as a biodegradable material for potential vascular stents application.

    Science.gov (United States)

    Niu, Jialin; Tang, Zibo; Huang, Hua; Pei, Jia; Zhang, Hua; Yuan, Guangyin; Ding, Wenjiang

    2016-12-01

    Zn-based alloys have been viewed as new potential materials for biodegradable implants, such as cardiovascular stents, mainly in consideration of their lower corrosion rate when compared with that of Mg alloys. In this study we developed a new Zinc-4wt.%Copper (Zn-4Cu) alloy as a biodegradable material. Hot extrusion was applied to Zn-4Cu to refine the microstructure and consequently improve its mechanical properties and corrosion resistance. After extrusion, dendritic CuZn5 phases were broken and distributed along the extrusion direction. The grains were refined obviously due to dynamical recrystallization. The yield strength (YS), ultimate tensile strength (UTS) and elongation of the as-extruded alloy are 250±10MPa, 270±10MPa and 51±2%, respectively. The corrosion rate of the as-extruded alloy in Hank's solution is about 9.41(±1.34)μmyear(-1). In vitro evaluation shows that Zn-4Cu presents acceptable toxicity to human endothelial cells, and could effectively inhibit bacteria adhesion and biofilm formation. The present study indicates that the as-extruded Zn-4Cu alloy exhibits excellent strength and ductility, uniform and slow degradation, good biocompatibility and significant antibacterial effect, which make it an excellent candidate material for biodegradable implants, especially for cardiovascular stents application. Copyright © 2016. Published by Elsevier B.V.

  19. Heparin and Vascular Endothelial Growth Factor Loaded Poly(L-lactide-co-caprolactone) Nanofiber Covered Stent-Graft for Aneurysm Treatment.

    Science.gov (United States)

    Wang, Jing; An, Qingzhu; Li, Dawei; Wu, Tong; Chen, Weiming; Sun, Binbin; El-Hamshary, Hany; Al-Deyab, Salem S; Zhu, Wei; Mo, Xiumei

    2015-11-01

    Restenosis caused by thrombopoiesis is one of the biggest hinders of endovascular stent-graft used in small-diameter vessels. Rapid endothelialization of the lumen of stent is a promising approach to prevent thrombosis. In this study, we aimed at loading heparin, a potent anticoagulants, and vascular endothelial growth factor (VEGF) into the core of poly(L-lactide-co-caprolactone) nanofiber via emulsion electrospinning. The nanofiber was covered on the stent and applied in the treatment of vascular diseases such as aneurysm. The morphologies of the emulsion electrospun nanofibers and core--shell structure were observed by scanning electron microscope and laser scanning confocal microscope. The release profiles of heparin and VEGF, degradation rate of nanofiber mats and cell proliferation in vitro were investigated. It was found that the release of both heparin and VEGF from the nanofiber lasted for more than 30 days without serious initial burst release. The degradation rate of nanofiber mats containing heparin and VEGF was faster than that of pure PLCL nanofiber mats. Moreover, the released VEGF could promote the proliferation of Pig iliac endothelial cells (PIECs) cultured on the nanofiber mat, which was of great benefit to stent endothelialization. The results of digital subtraction angiography (DSA) follow-up indicated the aneurysm was obliterated by separating the aneurysm dome from the blood circulation and the parent artery kept long-term patency. Results of the study demonstrated that the heparin and VEGF loaded nanofiber could provide an approach to fabricate covered stent-graft with properties of anticoagulation and induction of rapid endothelialization.

  20. Biodegradable vascular stents with high tensile and compressive strength: a novel strategy for applying monofilaments via solid-state drawing and shaped-annealing processes.

    Science.gov (United States)

    Im, Seung Hyuk; Kim, Chang Yong; Jung, Youngmee; Jang, Yangsoo; Kim, Soo Hyun

    2017-02-28

    Monofilaments such as those consisting of polyamide (PA), polydioxanone (PDS), and poly(vinylidene fluoride) (PVDF), have been commonly used in various industries. However, most are non-biodegradable, which is unfavorable for many biomedical applications. Although biodegradable polymers offer significant benefits, they are still limited by their weak mechanical properties, which is an obstacle for use as a biomaterial that requires high strength. To overcome the current limitations of biodegradable monofilaments, a novel solid-state drawing (SSD) process was designed to significantly improve the mechanical properties of both PA and poly(l-lactic acid) (PLLA) monofilaments in this study. Both PA and PLLA monofilaments exhibited more than two-fold increased tensile strength and a highly reduced thickness using SSD. In X-ray diffraction and scanning electron microscopy analyses, it was determined that SSD could not only promote the α-crystal phase, but also smoothen the surface of PLLA monofilaments. To apply SSD-monofilaments with superior properties to cardiovascular stents, a shaped-annealing (SA) process was designed as the follow-up process after SSD. Using this process, three types of vascular stents could be fabricated, composed of SSD-monofilaments: double-helix, single-spring and double-spring shaped stents. The annealing temperature was optimized at 80 °C to minimize the loss of mechanical and physical properties of SSD-monofilaments for secondary processing. All three types of vascular stents were tested according to ISO 25539-2. Consequently, it was confirmed that spring-shaped stents had good recovery rate values and a high compressive modulus. In conclusion, this study showed significantly improved mechanical properties of both tensile and compressive strength simultaneously and extended the potential for biomedical applications of monofilaments.

  1. Assessment of vascular response after drug-eluting stents implantation in patients with diabetes mellitus: an optical coherence tomography sub-study of the J-DESsERT.

    Science.gov (United States)

    Kubo, Takashi; Akasaka, Takashi; Tanimoto, Takashi; Takano, Masamichi; Seino, Yoshitane; Nasu, Kenya; Itoh, Tomonori; Mizuno, Kyoichi; Okura, Hiroyuki; Shinke, Toshiro; Kotani, Jun-Ichi; Ito, Shigenori; Yokoi, Hiroyoshi; Muramatsu, Toshiya; Nakamura, Masato; Nanto, Shinsuke

    2016-04-01

    Even in the drug-eluting stent era, diabetes mellitus (DM) patients have high incidences of restenosis and repeat revascularization after percutaneous coronary intervention. The aim of this study was to compare vascular response after stent implantation between sirolimus-eluting stent (SES) and paclitaxel-eluting stent (PES) by using optical coherence tomography (OCT) in DM patients as well as in non-DM patients. In the Japan-Drug Eluting Stents Evaluation; a Randomized Trial (J-DESsERT), the OCT sub-study enrolled 75 patients who underwent 8 months follow-up imaging after SES or PES implantation. Mean neointimal hyperplasia (NIH) thickness was significantly thinner in SES than PES in the DM group (77 ± 47 vs. 201 ± 114 μm, p < 0.001) and in the non-DM group (84 ± 37 vs. 212 ± 128 μm, p < 0.001). Unevenness of NIH thickness in longitudinal axis was significantly smaller in SES than PES in the DM group (348 ± 191 vs. 726 ± 385 μm, p < 0.001) and in the non-DM group (344 ± 174 vs. 679 ± 314 μm, p < 0.001). The percentage of uncovered struts was significantly greater in SES than PES in the DM group (24 ± 4 vs. 9 ± 14 %, p < 0.001) and in the non-DM group (16 ± 16 vs. 3 ± 4 %, p = 0.002). Compared with PES, SES showed more potent NIH inhibition in DM patients as well as in non-DM patients.

  2. Biodegradable and bioabsorbable stents.

    Science.gov (United States)

    Waksman, Ron; Pakala, Rajbabu

    2010-01-01

    Angioplasty of the coronary arteries has made significant headway in the past 20 years as a treatment for atherosclerotic vascular disease. Though drug-eluting stents are effective, they appear to invoke a thrombogenic response. Biodegradable stents are a promising alternative to permanent stents and may eventually be used to solve the lingering problem of in-stent restenosis. Additionally, fully degradable stents have the ability to deliver more drugs to the target site than a thin coating of drug on metallic stents. A variety of degradable materials have been studied for stent design, including polyesters, polycarbonates, bacterial-derived polymers, and corrodible metals. The ideal biodegradable stent would be reliably deployable under fluoroscopic guidance and situate into the target lesion with minimal endovascular trauma. The stent should degrade into nontoxic byproducts and invoke a minimal degree of inflammation at the target site. Finally, the stent itself should disappear within months (to years) without significant displacement from the deployment site. Although initial data from clinical trials have been sufficient to bring biodegradable materials into the realm of feasibility, future research is undoubtedly necessary to resolve the critical issues of inflammation and mechanical stability.

  3. Comparison of early clinical outcomes between ABSORB bioresorbable vascular scaffold and everolimus-eluting stent implantation in a real-world population.

    Science.gov (United States)

    Costopoulos, Charis; Latib, Azeem; Naganuma, Toru; Miyazaki, Tadashi; Sato, Katsumasa; Figini, Filippo; Sticchi, Alessandro; Carlino, Mauro; Chieffo, Alaide; Montorfano, Matteo; Colombo, Antonio

    2015-01-01

    To compare the early clinical outcomes between ABSORB bioresorbable vascular scaffold (BVS) (Abbott Vascular, Santa Clara, CA) and cobalt chromium everolimus-eluting stents in real-world patients with mostly complex disease. BVS represents the most interesting development in the drug-eluting stent field over recent years with promising results emerging from clinical trials. Available data however on the use of the ABSORB in real-world patients is limited. All patients (n = 92) treated with BVS and 1296 patients treated with EES were included in this study. Propensity score matching was performed to adjust for differences in baseline clinical characteristics, yielding 92 patient pairs (BVS = 92 patients with 137 lesions and EES = 92 patients with 124 lesions). Clinical outcomes were examined between the 2 groups at 6-months. In both groups, most lesions were classified as either B2 or C (83.9% vs. 77.4%, P = 0.19). Predilatation (97.8% vs. 75.8%, P < 0.01) as well as postdilation (99.3% vs. 77.4%, P < 0.01) was more common in the BVS group. Clinical outcomes at 6-months were similar between the two groups with respect to both target lesion revascularization (3.3% vs. 5.4%, P = 0.41) and major adverse cardiac events (defined as the composite of target vessel revascularization, follow-up myocardial infraction and all-cause death) (3.3% vs. 7.6%, P = 0.19). ABSORB BVS for the treatment of complex lesions appears to be associated with good procedural and early clinical outcomes similar to those observed with conventional drug-eluting stents. Larger studies with long-term follow-up are required in order to fully assess the role of BVS in the treatment of such lesions and how this compares with that of conventional stents. © 2014 Wiley Periodicals, Inc. © 2014 Wiley Periodicals, Inc.

  4. Angioplasty and Vascular Stenting

    Science.gov (United States)

    ... about radiology? Share your patient story here Images × Image Gallery Drawing illustrates angioplasty used for treating plaque. View full size with caption Related Articles and Media Magnetic Resonance Imaging (MRI) - Body Catheter Angiography Radiation Dose in X-Ray and ...

  5. 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 d...

  6. Negative vascular remodelling after implantation of bioabsorbable magnesium alloy stents in porcine coronary arteries: a randomised comparison with bare-metal and sirolimus-eluting stents

    DEFF Research Database (Denmark)

    Maeng, M; Jensen, Lisette Okkels; Falk, E

    2009-01-01

    randomly implanted in 31 porcine coronary arteries (n = 11 pigs). MAIN OUTCOME MEASURES: Neointima formation was measured by histomorphometry at 90 days. Vascular remodelling defined as change in external elastic membrane area from index intervention to follow-up was assessed by serial intravascular...

  7. Differential aspects between cobalt-chromium everolimus drug-eluting stent and Absorb everolimus bioresorbable vascular scaffold: from bench to clinical use

    NARCIS (Netherlands)

    Sotomi, Yohei; Suwannasom, Pannipa; Tenekecioglu, Erhan; Tateishi, Hiroki; Abdelghani, Mohammad; Serruys, Patrick W.; Onuma, Yoshinobu

    2015-01-01

    Drug-eluting stents have significantly improved the outcomes of percutaneous coronary intervention by substantially reducing in-stent restenosis and stent thrombosis. However, a potential limitation of these stents is the permanent presence of a metallic foreign body within the artery, which may

  8. On-demand drug release and hyperthermia therapy applications of thermoresponsive poly-(NIPAAm-co-HMAAm)/polyurethane core-shell nanofiber mat on non-vascular nitinol stents.

    Science.gov (United States)

    Aguilar, Ludwig Erik; GhavamiNejad, Amin; Park, Chan Hee; Kim, Cheol Sang

    2017-02-01

    A functional cover made up of core-shell nanofibers with a unique combination of thermoresponsive polymeric shell and stretchable polymeric core for non-vascular nitinol stents that uses an alternating magnetic field (AMF) to induce heat in the stent for hyperthermia therapy and simultaneously release 5-fluorouracil and/or paclitaxel was designed. Varying the ratios of NIPAAm to HMAAm monomer resulted in different LCST properties for the synthesized copolymer and further utilized for an on-demand drug release. Biocompatibility test using NIH-3T3 fibroblast cells indicates that the composite with drug content is biocompatible and the in-vitro cancer cytotoxicity test using ESO26 and OE21 cancer cells proved that the material shows cancer cytotoxic properties via combination of dual drug and hyperthermia therapy. With this functional material, we propose a tailorable and on-demand drug release with more control that can be employed for a combination drug therapy/single drug therapy combined with hyperthermia therapy for cancer cytotoxicity effect. Copyright © 2016 Elsevier Inc. All rights reserved.

  9. Enhanced in Vitro and in Vivo Performance of Mg-Zn-Y-Nd Alloy Achieved with APTES Pretreatment for Drug-Eluting Vascular Stent Application.

    Science.gov (United States)

    Liu, Jing; Zheng, Bo; Wang, Pei; Wang, Xingang; Zhang, Bin; Shi, Qiuping; Xi, Tingfei; Chen, Ming; Guan, Shaokang

    2016-07-20

    Bioabsorbable magnesium alloys are becoming prominent as temporary functional implants, as they avoid the risks generated by permanent metallic implants such as persistent inflammation and late restenosis. Nevertheless, the overfast corrosion of Mg alloys under physiological conditions hinders their wider application as medical implant materials. Here we investigate a simple one-step process to introduce a cross-linked 3-amino-propyltrimethoxysilane (APTES) silane physical barrier layer on the surface of Mg-Zn-Y-Nd alloys prior to electrostatic spraying with rapamycin-eluting poly(lactic-co-glycolic acid) (PLGA) layer. Surface microstructure was characterized by scanning electron microscope and Fourier transform infrared spectroscopy. Nanoscratch test verified the superior adhesion strength of PLGA coating in the group pretreated with APTES. Electrochemical tests combined with long-term immersion results suggested that the preferable in vitro anticorrosion behavior could be achieved by dense APTES barrier. Cell morphology and proliferation data demonstrated that APTES pretreated group resulted in remarkably preferable compatibility for both human umbilical vein endothelial cells and vascular smooth muscle cells. On the basis of excellent in vitro mechenical property, the animal study on the APTES pretreated Mg-Zn-Y-Nd stent implanted into porcine coronary arteries confirmed benign tissue compatibility as well as re-endothelialization without thrombogenesis or in-stent restenosis at six-month followup.

  10. The use of bioresorbable vascular scaffold Absorb BVS® in patients with stable coronary artery disease: one-year results with special focus on the hybrid bioresorbable vascular scaffolds and drug eluting stents treatment.

    Science.gov (United States)

    Gil, Robert J; Bil, Jacek; Pawłowski, Tomasz; Yuldashev, Nabijon; Kołakowski, Leszek; Jańczak, Jacek; Jabłoński, Wojciech; Paliński, Piotr

    The number of percutaneous coronary interventions (PCI) with bioresorbable vascular scaffolds (BVS) is in-creasing because these procedures offer additional benefits compared to PCI with classical drug eluting stents (DES) made of permanent metallic prostheses. To present the current experience of using BVS in a real life scenario in patients with stable coronary artery disease (CAD), with a special focus on the assessment of safety and effectiveness of the hybrid strategy (single stage BVS and DES implantation). We performed a one-arm prospective registry, which enrolled patients with stable CAD in five interventional cardiology centres in Poland. All patients who met inclusion and exclusion criteria and had received at least one BVS stent during index PCI were included. The primary endpoint was the cumulative rate of major adverse cardiovascular events (MACE), consist-ing of cardiac death, myocardial infarction (MI), and clinically-driven target lesion revascularisation (TLR) at 12 months. The analysis was performed in the whole population as well as in the subgroup with the hybrid treatment (BVS + DES). Between August 2013 and April 2014 139 patients were enrolled. The mean age was 59.5 ± 5.5 years, and 34.5% of the population were women. The target vessel was located in the left anterior descending artery in most cases (65.5%). The device success rate was 100%. At 12 months, in the whole population the cumulative MACE incidence was 7.2% (n = 10), while the clinically-driven TLR rate was 5.0% (n = 7). In further analysis, in the hybrid subgroup there was no death, MI, or stent thrombosis, and only one case of clinically-driven TLR (4.5%). The obtained data enable us to say that in particular clinical scenarios the simultaneous use of BVS and DES might be safe and effective.

  11. Polymers for Cardiovascular Stent Coatings

    Directory of Open Access Journals (Sweden)

    Anne Strohbach

    2015-01-01

    Full Text Available Polymers have found widespread applications in cardiology, in particular in coronary vascular intervention as stent platforms (scaffolds and coating matrices for drug-eluting stents. Apart from permanent polymers, current research is focussing on biodegradable polymers. Since they degrade once their function is fulfilled, their use might contribute to the reduction of adverse events like in-stent restenosis, late stent-thrombosis, and hypersensitivity reactions. After reviewing current literature concerning polymers used for cardiovascular applications, this review deals with parameters of tissue and blood cell functions which should be considered to evaluate biocompatibility of stent polymers in order to enhance physiological appropriate properties. The properties of the substrate on which vascular cells are placed can have a large impact on cell morphology, differentiation, motility, and fate. Finally, methods to assess these parameters under physiological conditions will be summarized.

  12. 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...

  13. Comparative study of the corrosion behavior of peripheral stents in an accelerated corrosion model: experimental in vitro study of 28 metallic vascular endoprostheses

    Science.gov (United States)

    Paprottka, Karolin J.; Paprottka, Philipp M.; Reiser, Maximilian F.; Waggershauser, Tobias

    2015-01-01

    PURPOSE Clinical cases of stent-fractures show that corrosion behavior might play a role in these fractures. Implanted in vivo, especially in combination with other implanted foreign materials, these metallic products are exposed to special conditions, which can cause a process of corrosion. Here, we aimed to test the corrosion potential of stents made of different materials in an in vitro setting. METHODS A total of 28 peripheral stents of different materials (nitinol, cobalt-chromium-nickel, tantalum, V4A) and surface treatments (electropolish, mechanical polish, no polish) were tested in vitro. Corrosion was accelerated by applying a constant voltage of 3.5 V and amperage of 1.16 mA in 0.9% NaCl. RESULTS Nitinol stents showed the lowest susceptibility to corrosion and the longest period without damage. The Memotherm II® (BARD Angiomed®) was the only stent that showed neither macroscopic nor microscopic damages. The worst performing material was cobalt-chromium-nickel, which showed corrosion damages about ten times earlier compared to nitinol. Considering the reasons for termination of the test, nitinol stents primarily showed length deficits, while V4A and tantalum stents showed fractures. Cobalt-chromium-nickel stents had multiple fractures or a complete lysis in equal proportions. When placed in direct contact, nitinol stents showed best corrosion resistance, regardless of what material they were combined with. In terms of polishing treatments, electropolished stents performed the best, mechanical-polished stents and those without polishing treatment followed. CONCLUSION The analysis of corrosion behavior may be useful to select the right stent fulfilling the individual needs of the patient within a large number of different stents. PMID:26268301

  14. Impact of lesion complexity on long-term vascular response to cobalt-chromium everolimus-eluting stent: five-year follow-up optical coherence tomography study.

    Science.gov (United States)

    Kuramitsu, Shoichi; Sonoda, Shinjo; Shinozaki, Tomohiro; Jinnouch, Hiroyuki; Muraoka, Yoshitaka; Domei, Takenori; Hyodo, Makoto; Shirai, Shinichi; Ando, Kenji; Otsuji, Yutaka

    2017-10-19

    The impact of lesion complexity on long-term vascular response to cobalt-chromium everolimus-eluting stent (CoCrEES) remains unclear. We sought to evaluate them using optical coherence tomography (OCT). A total of 47 patients with 58 lesions treated only with CoCrEES and no target-vessel events within 5 years after implantation were prospectively enrolled and underwent 5-year follow-up OCT. Quantitative parameters and qualitative characteristics of the neointima were evaluated using multilevel logistic or linear regression models with random effects at three levels: lesion, cross-section (CS), and strut. According to the lesion complexity, the lesions were classified into the two groups: the complex lesion (CL) and non-CL group. The CL was defined as having at least 1 high-risk feature such as acute coronary syndrome lesion, lesion length > 20 mm, severe calcification requiring rotational atherectomy, and chronic total occlusion at the index procedure. A total of 11,034 struts (CL, n = 6240; non-CL, n = 4794) and 1202 (CL, n = 683; non-CL, n = 519) CSs were analyzed. The percentage of uncovered and malapposed struts did not differ significantly between the CL and non-CL groups (0.90 vs. 0.54%, P = 0.78; 0.56 vs. 0.10%, P = 0.16, respectively). The incidence of neoatherosclerosis was comparable between both groups in the CS- and lesion-level analysis (3.5 vs. 4.6%, P = 0.91; 32.0 vs. 24.2%, P = 0.52, respectively). At 5 years, CoCrEES shows an excellent vascular healing and similar frequency of neoatheroslerosis in patients without target-vessel events, regardless of the lesion complexity.

  15. Outcome of everolimus eluting bioabsorbable vascular scaffold (BVS) compared to non BVS drug eluting stent in the management of ST-segment elevation myocardial infarction (STEMI) — A comparative study

    Energy Technology Data Exchange (ETDEWEB)

    Chakraborty, Rabin; Patra, Soumya, E-mail: dr_soumyapatra@rediffmail.com; Banerjee, Suvro; Pande, Arindam; Khan, Aftab; Mandol, Prakash Chandra; Ghosh, Debashish; De, Swapan Kumar; Das, Sankha Subhro; Nag, Raja

    2016-04-15

    Background: The safety and efficacy of everolimus eluting bioabsorbable vascular scaffold (BVS) in the management of “ST” segment elevation myocardial infarction (STEMI) are yet to be established. Aims: To evaluate immediate and short term safety and efficacy of the everolimus-eluting ABSORB BVS compared with non BVS drug eluting stent (DES) in patients with STEMI. Methods: From December 2013 to December 2014, 220 patients with STEMI were included in this study. Among them, 35 patients treated with BVS were compared with a control group composed of 180 patients who underwent non BVS DES implantation in the same time period. The incidence of major adverse cardiac events (MACE: stent thrombosis: death, non-fatal myocardial infarction, or target vessel/lesion revascularization) before discharge and up to six months was evaluated. Results: 1 vessel disease was more frequent whereas, 2 and 3 vessel disease was less frequent in BVS group. Procedural characteristics were also similar between groups, except for the use of post dilation (p = 0.04). Procedural success, in-hospital, and up to six-month MACE rates were similar between both groups. Definite or probable stent thrombosis did not occur (according to the ARC criteria) in BVS patients, though two patients during the index admission and another two patients in the first month after DES implantation had stent thrombosis. Conclusion: The use of the ABSORB BVS for STEMI is feasible and associated with good procedural safety, and angiographic success rate.

  16. 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

  17. [Study on a novel vascular stent material (titanium oxide, Ti-O) coated with albumin and heparin: is it hemocompatible with fibrinogen].

    Science.gov (United States)

    Song, Jie; Wu, Xi; Huang, Nan; Xu, Biao; Jing, Fengjuan; Chen, Junying; Leng, Yongxiang; Yang, Ping; Wang, Jin; Sun, Hong; Zhao, Ansha

    2007-10-01

    The functional hemocompatibility between fibrinogen (FIG) and a novel vascular stent material (Ti-O film fixed with albumin and heparin) was investigated as follows: (1) Preparing the new biologic material (Ti-O) film; (2) Coating albumin and heparin on the Ti-O film; (3) Testing platelets (PL) adsorption; (4) Determining FIG adhesion number by use of enzyme linked immunoassay (ELISA); (5) Implanting the films from the test group of Ti-O film and from the comparison group of stainless steel (SS) film into the left and right femoral arteries respectively in 4 dogs. It was proved that albumin and heparin were fixed on Ti-O film. After 6 months, the femoral arteries of the dogs were resected. In the test group of Ti-O film coated with albumin and heparin, few PL adhered to the coat, their form did not change, and no thrombus was found by scanning electron microscopy; the result was better than that of plain Ti-O film, and was much better than that of SS film. Ti-O maintained normal transformation condition of FIG, and no C terminal of gamma chain in FIG was revealed. As it is known whether the hemocompatibility of a biomaterial is good depends upon its adsorption of FIG, and Ti-O has excellent reaction on albumin and heparin by chemical processes. In this study, the Ti-O film coated with albumin and heparin further reduced the absorption of FIG and PL when compared against the plain Ti-O film. So the Ti-O film coated with albumin and heparin has the insistent and permanent anticoagulant character.

  18. Dual Delivery of BMP-2 and bFGF from a New Nano-Composite Scaffold, Loaded with Vascular Stents for Large-Size Mandibular Defect Regeneration

    Directory of Open Access Journals (Sweden)

    Hang Zhao

    2013-06-01

    Full Text Available The aim of this study was to investigate the feasibility and advantages of the dual delivery of bone morphogenetic protein-2 (BMP-2 and basic fibroblast growth factor (bFGF from nano-composite scaffolds (PLGA/PCL/nHA loaded with vascular stents (PLCL/Col/nHA for large bone defect regeneration in rabbit mandibles. Thirty-six large bone defects were repaired in rabbits using engineering bone composed of allogeneic bone marrow mesenchymal stem cells (BMSCs, bFGF, BMP-2 and scaffolds composed of PLGA/PCL/nHA loaded with PLCL/Col/nHA. The experiments were divided into six groups: BMSCs/bFGF/BMP-2/scaffold, BMSCs/BMP-2/scaffold, BMSCs/bFGF/scaffold, BMSCs/scaffold, scaffold alone and no treatment. Sodium alginate hydrogel was used as the carrier for BMP-2 and bFGF and its features, including gelling, degradation and controlled release properties, was detected by the determination of gelation and degradation time coupled with a controlled release study of bovine serum albumin (BSA. AlamarBlue assay and alkaline phosphatase (ALP activity were used to evaluate the proliferation and osteogenic differentiation of BMSCs in different groups. X-ray and histological examinations of the samples were performed after 4 and 12 weeks post-implantation to clarify new bone formation in the mandible defects. The results verified that the use of sodium alginate hydrogel as a controlled release carrier has good sustained release ability, and the combined application of bFGF and BMP-2 could significantly promote the proliferation and osteogenic differentiation of BMSCs (p < 0.05 or p < 0.01. In addition, X-ray and histological examinations of the samples exhibited that the dual release group had significantly higher bone formation than the other groups. The above results indicate that the delivery of both growth factors could enhance new bone formation and vascularization compared with delivery of BMP-2 or bFGF alone, and may supply a promising way of repairing large

  19. Asymmetric dimethyl arginine induces pulmonary vascular dysfunction via activation of signal transducer and activator of transcription 3 and stabilization of hypoxia-inducible factor 1-alpha.

    Science.gov (United States)

    Pekarova, Michaela; Koudelka, Adolf; Kolarova, Hana; Ambrozova, Gabriela; Klinke, Anna; Cerna, Anna; Kadlec, Jaroslav; Trundova, Maria; Sindlerova Svihalkova, Lenka; Kuchta, Radek; Kuchtova, Zdenka; Lojek, Antonin; Kubala, Lukas

    2015-10-01

    Pulmonary hypertension (PH), associated with imbalance in vasoactive mediators and massive remodeling of pulmonary vasculature, represents a serious health complication. Despite the progress in treatment, PH patients typically have poor prognoses with severely affected quality of life. Asymmetric dimethyl arginine (ADMA), endogenous inhibitor of endothelial nitric oxide synthase (eNOS), also represents one of the critical regulators of pulmonary vascular functions. The present study describes a novel mechanism of ADMA-induced dysfunction in human pulmonary endothelial and smooth muscle cells. The effect of ADMA was compared with well-established model of hypoxia-induced pulmonary vascular dysfunction. It was discovered for the first time that ADMA induced the activation of signal transducer and activator of transcription 3 (STAT3) and stabilization of hypoxia inducible factor 1α (HIF-1α) in both types of cells, associated with drastic alternations in normal cellular functions (e.g., nitric oxide production, cell proliferation/Ca(2+) concentration, production of pro-inflammatory mediators, and expression of eNOS, DDAH1, and ICAM-1). Additionally, ADMA significantly enhanced the hypoxia-mediated increase in the signaling cascades. In summary, increased ADMA may lead to manifestation of PH phenotype in human endothelial and smooth muscle cells via the STAT3/HIF-1α cascade. Therefore this signaling pathway represents the potential pathway for future clinical interventions in PH. Copyright © 2015 Elsevier Inc. All rights reserved.

  20. Intimal hyperplasia and vascular remodeling after everolimus-eluting and sirolimus-eluting stent implantation in diabetic patients the randomized diabetes and drug-eluting stent (DiabeDES) IV intravascular ultrasound trial

    DEFF Research Database (Denmark)

    Antonsen, Lisbeth; Maeng, Michael; Thayssen, Per

    2013-01-01

    in 88 patients, including 48 EES and 40 SES treated patients. IVUS endpoints included IH volume, in-stent % volume obstruction and changes in external elastic membrane (EEM) volume. RESULTS: Compared with the SES group, IH volume was increased in the EES group [median (interquartile range): 2.8 mm(3) (0.......0-12.6) vs. 0.0 mm(3) (0.0-1.1), P = 0.001]. In-stent % volume obstruction was increased in EES compared to SES [median (interquartile range): 1.6% (0.0-8.2) vs. 0.0% (0.0-1.0), P = 0.001]. Peri-stent external elastic membrane (EEM) volume: (post procedure vs. follow-up EES [300 mm(3) (219-491) vs. 307 mm(3...

  1. Angioplasty and stent placement - peripheral arteries

    Science.gov (United States)

    ... blood flow. A stent is a small, metal mesh tube that keeps the artery open. Angioplasty and ... 1570. PMID: 23473760 www.ncbi.nlm.nih.gov/pubmed/23473760 . Society for Vascular Surgery Lower Extremity Guidelines ...

  2. Economic Outcomes of Bioresorbable Vascular Scaffolds Versus Everolimus-Eluting Stents in Patients Undergoing Percutaneous Coronary Intervention: 1-Year Results From the ABSORB III Trial.

    Science.gov (United States)

    Baron, Suzanne J; Lei, Yang; Chinnakondepalli, Khaja; Vilain, Katherine; Magnuson, Elizabeth A; Kereiakes, Dean J; Ellis, Stephen G; Stone, Gregg W; Cohen, David J

    2017-04-24

    The purpose of this study was to evaluate the economic impact of the Absorb bioresorbable vascular scaffold compared with the Xience everolimus-eluting stent in patients undergoing percutaneous coronary intervention. The ABSORB III trial (Everolimus-Eluting Bioresorbable Scaffolds for Coronary Artery Disease) demonstrated that the Absorb scaffold was noninferior to the Xience stent with respect to target lesion failure at 1 year. Whether health care costs differ between the Absorb scaffold and the Xience stent is unknown. We performed a prospective health economic study alongside the ABSORB III trial, in which patients undergoing percutaneous coronary intervention for stable or unstable angina were randomized to receive the Absorb scaffold (n = 1,322) or Xience stent (n = 686). Resource use data were collected through 1 year of follow-up. Costs were assessed using resource-based accounting (for procedures), MedPAR data (for other index hospitalization costs), and Medicare reimbursements (for follow-up costs and physician fees). Initial procedural costs were higher with the Absorb scaffold than the Xience stent ($6,316 ± 1,892 vs. $6,103 ± 1,895; p = 0.02), driven mainly by greater balloon catheter use and the higher cost of the scaffold in the Absorb group. Nonetheless, index hospitalization costs ($15,035 ± 2,992 for Absorb vs. $14,903 ± 3,449 for Xience; p = 0.37) and total 1-year costs ($17,848 ± 6,110 for Absorb vs. $17,498 ± 7,411 for Xience; p = 0.29) were similar between the 2 groups. Although initial procedural costs were higher with the Absorb scaffold, there were no differences in total 1-year health care costs between the 2 cohorts. Longer term follow-up is needed to determine whether meaningful cost savings emerge after scaffold resorption. (A Clinical Evaluation of Absorb™ BVS, the Everolimus-Eluting Bioresorbable Vascular Scaffold in the Treatment of Subjects With de Novo Native Coronary Artery Lesions; NCT01751906). Copyright © 2017

  3. Early vascular responses to everolimus-eluting cobalt-chromium stent in the culprit lesions of st-elevation myocardial infarction: results from a multicenter prospective optical coherence tomography study (MECHANISM-AMI 2-week follow-up study).

    Science.gov (United States)

    Morino, Yoshihiro; Terashita, Daisuke; Otake, Hiromasa; Kikuchi, Tatsuo; Fusazaki, Tetsuya; Kuriyama, Nehiro; Suzuki, Takahide; Ito, Yoshiaki; Hibi, Kiyoshi; Tanaka, Hiroyuki; Ishihara, Shozo; Kataoka, Toru; Morita, Takashi; Otsuka, Yoritaka; Hayashi, Takatoshi; Tanabe, Kengo; Shinke, Toshiro

    2018-01-09

    The use of cobalt-chromium everolimus-eluting stents (CoCr-EES) for ST-segment elevation myocardial infarction (STEMI) reduces the incidence of stent thrombosis compared with bare metal stents, and a substantial difference is apparent in the initial 2 weeks. However, vascular behavior during this early period remains unclear. This was a prospective study (MECHANISM-AMI-2W) to investigate early vascular responses in STEMI patients immediately after CoCr-EES implantation and at 2-week follow-up using frequency domain-optical coherence tomography (FD-OCT). The study enrolled 52 patients (age 63.7 ± 11.7 years, male 85.0%), of whom 44 patients were available for complete serial FD-OCT analyses. Both % uncovered struts and % malapposed struts were improved at 2-week follow-up (63 ± 20 vs. 21 ± 14%, p stent (28.8 ± 27.7 vs. 18.1 ± 20.2%, p = 0.0001) and maximal area (0.93 ± 0.84 vs. 0.65 ± 0.63 mm2, p = 0.034). As a result, the average lumen area was significantly larger at 2 weeks (6.49 ± 1.82 vs. 6.71 ± 1.89 mm2, p = 0.048, respectively). The number of dissection flaps was lower (0.86 ± 1.11 vs. 0.52 ± 0.90%, p = 0.024). In conclusion, this study showed early vascular responses to CoCr-EES for STEMI lesions-including a significant reduction of thrombus-that resulted in lumen enlargement, earlier progression of strut coverage, and improvements in strut apposition and dissection. The combination of these factors may therefore be responsible for the safety of CoCr-EES within the initial 2 weeks.

  4. Serum Levels of Asymmetric Dimethylarginine and Apelin as Potential Markers of Vascular Endothelial Dysfunction in Early Rheumatoid Arthritis

    Directory of Open Access Journals (Sweden)

    Manuela Di Franco

    2012-01-01

    Full Text Available Objectives. Impaired endothelial function represents the early stage of atherosclerosis, which is typically associated with systemic inflammatory diseases like rheumatoid arthritis (RA. As modulators of endothelial nitric oxide synthase expression, asymmetric-dimethylarginine (ADMA and apelin might be measured in the blood of RA patients to detect early atherosclerotic changes. We conducted a prospective, case-control study to investigate serum ADMA and apelin profiles of patients with early-stage RA (ERA before and after disease-modifying antirheumatic drug (DMARD therapy. Methods. We enrolled 20 consecutively diagnosed, treatment-naïve patients with ERA and 20 matched healthy controls. Serum ADMA and apelin levels and the 28-joint disease activity scores (DAS28 were assessed before and after 12 months of DMARDs treatment. All patients underwent ultrasonographic assessment for intima-media tickness (IMT evaluation. Results. In the ERA group, ADMA serum levels were significantly higher than controls at baseline (P=0.007 and significantly decreased after treatment (P=0.012 versus controls. Baseline serum apelin levels were significantly decreased in this group (P=0.0001 versus controls, but they were not significantly altered by treatment. IMT did not show significant changes. Conclusions. ERA is associated with alterations of serum ADMA and apelin levels, which might be used as biomarkers to detect early endothelial dysfunction in these patients.

  5. Effect of Lowering Asymmetric Dimethylarginine (ADMA on Vascular Pathology in Atherosclerotic ApoE-Deficient Mice with Reduced Renal Mass

    Directory of Open Access Journals (Sweden)

    Johannes Jacobi

    2014-03-01

    Full Text Available The purpose of the work was to study the impact of the endogenous nitric oxide synthase (NOS inhibitor asymmetric dimethylarginine (ADMA and its degrading enzyme, dimethylarginine dimethylaminohydrolase (DDAH1, on atherosclerosis in subtotally nephrectomized (SNX ApoE-deficient mice. Male DDAH1 transgenic mice (TG, n = 39 and C57Bl/6J wild-type littermates (WT, n = 27 with or without the deletion of the ApoE gene underwent SNX at the age of eight weeks. Animals were sacrificed at 12 months of age, and blood chemistry, as well as the extent of atherosclerosis within the entire aorta were analyzed. Sham treated (no renal mass reduction ApoE-competent DDAH1 transgenic and wild-type littermates (n = 11 served as a control group. Overexpression of DDAH1 was associated with significantly lower ADMA levels in all treatment groups. Surprisingly, SNX mice did not exhibit higher ADMA levels compared to sham treated control mice. Furthermore, the degree of atherosclerosis in ApoE-deficient mice with SNX was similar in mice with or without overexpression of DDAH1. Overexpression of the ADMA degrading enzyme, DDAH1, did not ameliorate atherosclerosis in ApoE-deficient SNX mice. Furthermore, SNX in mice had no impact on ADMA levels, suggesting a minor role of this molecule in chronic kidney disease (CKD in this mouse model.

  6. Early vascular healing with rapid breakdown biodegradable polymer sirolimus-eluting versus durable polymer everolimus-eluting stents assessed by optical coherence tomography

    Energy Technology Data Exchange (ETDEWEB)

    Tada, Tomohisa, E-mail: tomohisa@dhm.mhn.de [Deutsches Herzzentrum, Technische Universität, München (Germany); Byrne, Robert A. [Deutsches Herzzentrum, Technische Universität, München (Germany); Schuster, Tibor [Institut für Medizinische Statistik und Epidemiologie, München (Germany); Cuni, Rezarta [Deutsches Herzzentrum, Technische Universität, München (Germany); Kitabata, Hironori [Wakayama Medical University, Wakayama (Japan); Tiroch, Klaus [Deutsches Herzzentrum, Technische Universität, München (Germany); Dirninger, Alfred; Gratze, Franz; Kaspar, Klaus; Zenker, Gerald [Landeskrankenhaus Bruck/Mur (Austria); Joner, Michael; Schömig, Albert; Kastrati, Adnan [Deutsches Herzzentrum, Technische Universität, München (Germany)

    2013-03-15

    Background: Differences in early arterial healing patterns after stent implantation between biodegradable and durable polymer based new generation drug-eluting stents are not well understood. The aim of this study was to compare the healing patterns of a novel rapid breakdown (≤ 8 weeks) biodegradable polymer sirolimus-eluting stent (BP-SES) with a durable polymer everolimus-eluting stent (EES) using intravascular optical coherence tomography (OCT) at 4 months. Methods: A total of 20 patients were randomly assigned to stenting with BP-SES (n = 11) or EES (n = 9). Overall intravascular imaging was available for 15 (75%) patients. The primary endpoint was the difference in rate of uncovered struts between BP-SES and EES. To account for strut-level clustering, the results in both treatment groups were compared using a generalized linear mixed model approach. Results: Regarding the primary endpoint, BP-SES as compared to EES showed similar rates of uncovered struts (37 [6.8%] versus 167 [17.5%], odds ratio (OR) 0.45 (95% CI 0.09-2.24), p = 0.33). There were no malapposed struts in BP-SES group and 14 malapposed struts in EES group (p = 0.97). No difference in percent neointimal volume (14.1 ± 8.2% vs. 11.4 ± 6.4%, p = 0.56) was observed. Conclusions: Although rapid-breakdown BP-SES as compared to EES showed signs of improved early tissue coverage, after adjustment for strut-level clustering these differences were not statistically significant. No differences in ability to suppress neointimal hyperplasia after stent implantation between 2 stents were observed.

  7. The conical stent in coronary artery improves hemodynamics compared with the traditional cylindrical stent.

    Science.gov (United States)

    Yu, Yi; Zhou, Yujie; Ma, Qian; Jia, Shuo; Wu, Sijing; Sun, Yan; Liu, Xiaoli; Zhao, Yingxin; Liu, Yuyang; Shi, Dongmei

    2017-01-15

    This study sought to explore the efficacy of the conical stent implantation in the coronary artery by comparing the effects of cylindrical and conical stents on wall shear stress (WSS) and velocity of flow and fractional flow reserve (FFR). The traditional cylindrical stent currently used in the percutaneous coronary intervention (PCI) has a consistent diameter, which does not match the physiological change of the coronary artery. On the contrary, as a new patent, the conical stent with tapering lumen is consistent with the physiological change of vascular diameter. However, the effect of the conical stent implantation on the coronary hemodynamics remains unclear. The coronary artery, artery stenosis and two stent models were established by Solidworks software. All models were imported into the computational fluid dynamics (CFD) software ANSYS ICEM-CFD to establish the fluid model. After the boundary conditions were set, CFD analysis was proceeded to compare the effects of two stent implantation on the change of WSS, velocity of flow and FFR. Hemodynamic indexes including FFR, blood flow velocity distribution (BVD) and WSS were improved by either the cylindrical or the conical stent implantation. However, after the conical stent implantation, the change of FFR seemed to be slower and more homogenous; the blood flow velocity was more appropriate without any obvious blood stagnation and direction changes; the WSS after the conical stent implantation was uniform from the proximal to distal side of the stent. Compared with the cylindrical stent, the conical stent implantation in the coronary artery can make the changes of vascular hemodynamic more closer to the physiological condition, which can reduce the incidence of intra-stent restenosis and thrombosis, thus making it more suitable for PCI therapy. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  8. Coronary artery stent (image)

    Science.gov (United States)

    ... blocked. The stent is inserted along with a balloon catheter and expands when the balloon is inflated. The stent is ... blocked. The stent is inserted along with a balloon catheter and expands when the balloon is inflated. The stent is ...

  9. Stenting for curved lesions using a novel curved balloon: Preliminary experimental study.

    Science.gov (United States)

    Tomita, Hideshi; Higaki, Takashi; Kobayashi, Toshiki; Fujii, Takanari; Fujimoto, Kazuto

    2015-08-01

    Stenting may be a compelling approach to dilating curved lesions in congenital heart diseases. However, balloon-expandable stents, which are commonly used for congenital heart diseases, are usually deployed in a straight orientation. In this study, we evaluated the effect of stenting with a novel curved balloon considered to provide better conformability to the curved-angled lesion. In vitro experiments: A Palmaz Genesis(®) stent (Johnson & Johnson, Cordis Co, Bridgewater, NJ, USA) mounted on the Goku(®) curve (Tokai Medical Co. Nagoya, Japan) was dilated in vitro to observe directly the behavior of the stent and balloon assembly during expansion. Animal experiment: A short Express(®) Vascular SD (Boston Scientific Co, Marlborough, MA, USA) stent and a long Express(®) Vascular LD stent (Boston Scientific) mounted on the curved balloon were deployed in the curved vessel of a pig to observe the effect of stenting in vivo. In vitro experiments: Although the stent was dilated in a curved fashion, stent and balloon assembly also rotated conjointly during expansion of its curved portion. In the primary stenting of the short stent, the stent was dilated with rotation of the curved portion. The excised stent conformed to the curved vessel. As the long stent could not be negotiated across the mid-portion with the balloon in expansion when it started curving, the mid-portion of the stent failed to expand fully. Furthermore, the balloon, which became entangled with the stent strut, could not be retrieved even after complete deflation. This novel curved balloon catheter might be used for implantation of the short stent in a curved lesion; however, it should not be used for primary stenting of the long stent. Post-dilation to conform the stent to the angled vessel would be safer than primary stenting irrespective of stent length. Copyright © 2014 Japanese College of Cardiology. Published by Elsevier Ltd. All rights reserved.

  10. 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. Copyright © 2011 John Wiley & Sons, Inc.

  11. Stents medicados en Cardiología intervencionista

    OpenAIRE

    César Hernández

    2017-01-01

    Los stent medicados constituyen la incorporación a la plataforma de metal del stent de un medicamento citotóxico o citostático de liberación retardada que inhibe la proliferación celular, especialmente del músculo liso vascular, responsable de la reestenosis del stent. Los tres componentes de los stent medicados son la plataforma o stent, el mecanismo de liberación (polímero) y el medicamento liberado. Han sido clasificados en cuatro generaciones de acuerdo con las características del polímer...

  12. Patient profile and periprocedural outcomes of bioresorbable vascular scaffold implantation in comparison with drug-eluting and bare-metal stent implantation. Experience from ORPKI Polish National Registry 2014–2015

    Directory of Open Access Journals (Sweden)

    Łukasz Rzeszutko

    2016-11-01

    Full Text Available Introduction: There are limited data on the comparison of bioresorbable vascular scaffold (BVS and drug-eluting stent (DES/bare-metal stent (BMS implantation in an unselected population of patients with coronary artery disease. Aim : To compare the periprocedural outcomes and patient profile of BVS and DES/BMS implantation in an all-comer population from the ORPKI Polish National Registry. Material and methods: A total of 141,324 consecutive patients from 151 invasive cardiology centers in Poland were included in this prospective registry between January 2014 and June 2015. Periprocedural data on patients with at least one BVS (Absorb, Abbott Vascular, Santa Clara, CA, USA, DES or BMS (all available types implantation in de novo lesions during index percutaneous coronary intervention for stable angina (SA or acute coronary syndrome were collected. Results : Bioresorbable vascular scaffold was the most often used in patients with SA, in single-vessel disease and in younger male patients. Bioresorbable vascular scaffold implantation was significantly more often associated with periprocedural administration of ticagrelor/prasugrel (6.8% vs. 3.6%; p = 0.001 and use of intravascular ultrasound and optical coherence tomography in comparison with the DES/BMS group (2.8% vs. 0.6% and 1.8% vs. 0.1%, respectively; p = 0.001 for both. The incidence of periprocedural death was significantly lower in the BVS group than the DES/BMS group (0.04% vs. 0.32%; p = 0.02, but this difference was no longer significant after adjustment for covariates. On the other hand, coronary artery perforation occurred significantly more often during BVS delivery (0.31% vs. 0.12%; p = 0.01, and BVS implantation was identified as an independent predictor of coronary artery perforation in multivariate logistic regression analysis (OR = 6.728, 95% CI: 2.394–18.906; p = 0.001. Conclusions : Patients treated with BVS implantation presented an acceptable safety and efficacy profile in

  13. Carotid stenting and endarterectomy.

    Science.gov (United States)

    Yip, Hon-Kan; Sung, Pei-Hsun; Wu, Chiung-Jen; Yu, Cheuk-Man

    2016-07-01

    Stroke, either ischemic or hemorrhagic, remains the second commonest cause of death worldwide in the last decade. Etiologies for ischemic stroke (IS) vary widely. Atherothrombotic occlusion is an essential cause to which carotid artery stenosis (CAS) is a major contributor. Administration of anti-platelet agent to patients with CAS has been shown to reduce incidence of long-term IS. In additional, in patients with symptomatic CAS, clinical trials have demonstrated that carotid endarterectomy (CEA) is superior to medical therapy for prevention of future CAS-related IS. However, CEA is not suitable for CAS post-radiotherapy or those located at higher level of the internal carotid artery; and major complications of this procedure including cranial nerve injuries have stimulated the interest of using percutaneous transfemoral carotid stenting as an alternative approach. Although transfemoral arterial approach of carotid stenting is not inferior to CEA in improving clinical outcomes, it has been reported to be associated with vascular complication and has its limitations in patients with athero-occlusive disease of abdominal aorta or bilateral iliac arteries, level II or III aortic arch, or bovine type carotid arterial anatomy. Therefore, transradial/transbrachial arterial approach has emerged as a novel method for carotid stenting. This article provides a critical review on interventional approaches for the treatment of CAS. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  14. Using COMSOL Multiphysics for Biomechanical Analysis of Stent Technology in Cerebral Aneurysms

    DEFF Research Database (Denmark)

    Rasmussen, Joachim; Thyregod, Jesper; Enevoldsen, Marie Sand

    2009-01-01

    This work presents new fluid-structure interaction (FSI) models in both 2D and 3D of the effect of using vascular stents as treatment of cerebral berry aneurysms. The stent is positioned inside the cerebral artery covering the neck of the aneurysm. The stent is expected to alter the blood flow in...

  15. Upper Gastrointestinal Stent

    OpenAIRE

    Kim, Sang Gyun; Yang, Chang-Hun

    2012-01-01

    Gastrointestinal (GI) stent has been developed for palliation of obstructive symptoms in various diseases causing obstruction of GI tract. Self-expanding metal stent (SEMS) has replaced old type of plastic stent, and endoscopic insertion of stent has replaced fluoroscopy-guided insertion. Nowadays, newly-designed SEMSs have been developed for prevention of complications such as stent migration and re-obstruction, and indications of stent recently have been widened into benign conditions as we...

  16. 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.

  17. Vascular biliopathy as a cause of common bile duct obstruction successfully treated by mesocaval shunt and endoscopic retrograde cholangiopancreatography biliary stent placement.

    Science.gov (United States)

    Rosenthal, Martin D; White, Geoffrey H; Stephen, Michael S; Gallagher, James J; Sandroussi, Charbel

    2008-01-01

    Common bile duct stenosis owing to extrahepatic portal varices is termed "portal hypertensive biliopathy" (PHB) and is a rare occurrence. We report a case of PHB owing to portal vein thrombosis with cavernous transformation successfully managed by mesocaval shunt and endoscopic retrograde cholangiopancreatography (ERCP) biliary stent placement. A 44-year-old male, who presented with hematemesis, melena, jaundice, and abdominal pain, underwent gastroscopy, which revealed bleeding gastric varices. Computed tomography with arterial and venous imaging demonstrated portal vein thrombosis with cavernous transformation and extensive extrahepatic varices within the porta hepatis causing common bile duct obstruction from extrinsic compression. Biliary decompression was achieved with ERCP, and a small common bile duct stone was retrieved. A mesocaval shunt with a 16 mm Dacron graft successfully treated the portal hypertension. PHB is rare. We report a case successfully treated by mesocaval shunt and ERCP.

  18. Magnetizable stent-grafts enable endothelial cell capture

    Energy Technology Data Exchange (ETDEWEB)

    Tefft, Brandon J. [Department of Cardiovascular Diseases, Mayo Clinic, Rochester, MN (United States); Uthamaraj, Susheil [Division of Engineering, Mayo Clinic, Rochester, MN (United States); Harburn, J. Jonathan [School of Medicine, Pharmacy and Health, Durham University, Stockton-on-Tees (United Kingdom); Hlinomaz, Ota [Department of Cardioangiology, St. Anne' s University Hospital, Brno (Czech Republic); Lerman, Amir [Department of Cardiovascular Diseases, Mayo Clinic, Rochester, MN (United States); Dragomir-Daescu, Dan [Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, MN (United States); Sandhu, Gurpreet S., E-mail: sandhu.gurpreet@mayo.edu [Department of Cardiovascular Diseases, Mayo Clinic, Rochester, MN (United States)

    2017-04-01

    Emerging nanotechnologies have enabled the use of magnetic forces to guide the movement of magnetically-labeled cells, drugs, and other therapeutic agents. Endothelial cells labeled with superparamagnetic iron oxide nanoparticles (SPION) have previously been captured on the surface of magnetizable 2205 duplex stainless steel stents in a porcine coronary implantation model. Recently, we have coated these stents with electrospun polyurethane nanofibers to fabricate prototype stent-grafts. Facilitated endothelialization may help improve the healing of arteries treated with stent-grafts, reduce the risk of thrombosis and restenosis, and enable small-caliber applications. When placed in a SPION-labeled endothelial cell suspension in the presence of an external magnetic field, magnetized stent-grafts successfully captured cells to the surface regions adjacent to the stent struts. Implantation within the coronary circulation of pigs (n=13) followed immediately by SPION-labeled autologous endothelial cell delivery resulted in widely patent devices with a thin, uniform neointima and no signs of thrombosis or inflammation at 7 days. Furthermore, the magnetized stent-grafts successfully captured and retained SPION-labeled endothelial cells to select regions adjacent to stent struts and between stent struts, whereas the non-magnetized control stent-grafts did not. Early results with these prototype devices are encouraging and further refinements will be necessary in order to achieve more uniform cell capture and complete endothelialization. Once optimized, this approach may lead to more rapid and complete healing of vascular stent-grafts with a concomitant improvement in long-term device performance. - Highlights: • Magnetic stent-grafts were made from 2205 steel stents and polyurethane nanofibers. • Stent-grafts remained patent and formed a thin and uniform neointima when implanted. • Stent-grafts captured endothelial cells labeled with magnetic nanoparticles.

  19. Forming of magnesium alloy microtubes in the fabrication of biodegradable stents

    NARCIS (Netherlands)

    Wang, L.; Fang, G.; Qian, L.; Leeflang, M.A.; Duszczyk, J.; Zhou, J.

    2014-01-01

    Magnesium alloys have, in recent years, been recognized as highly promising biodegradable materials, especially for vascular stent applications. Forming of magnesium alloys into high-precision thin-wall tubes has however presented a technological barrier in the fabrication of vascular stents,

  20. Recommendations for the use of bioresorbable vascular scaffolds in percutaneous coronary interventions

    NARCIS (Netherlands)

    Everaert, B.; Wykrzykowska, J. J.; Koolen, J.; van der Harst, P.; den Heijer, P.; Henriques, J. P.; van der Schaaf, R.; de Smet, B.; Hofma, S. H.; Diletti, R.; Weevers, A.; Hoorntje, J.; Smits, P.; van Geuns, R. J.

    Background: To eliminate some of the potential late limitations of permanent metallic stents, the bioresorbable coronary stents or 'bioresorbable vascular scaffolds' (BVS) have been developed. Methods: We reviewed all currently available clinical data on BVS implantation. Results: Since the 2015

  1. Comparison of Ticagrelor Versus Prasugrel for Inflammation, Vascular Function, and Circulating Endothelial Progenitor Cells in Diabetic Patients With Non-ST-Segment Elevation Acute Coronary Syndrome Requiring Coronary Stenting: A Prospective, Randomized, Crossover Trial.

    Science.gov (United States)

    Jeong, Han Saem; Hong, Soon Jun; Cho, Sang-A; Kim, Jong-Ho; Cho, Jae Young; Lee, Seung Hun; Joo, Hyung Joon; Park, Jae Hyoung; Yu, Cheol Woong; Lim, Do-Sun

    2017-08-28

    This study compared adenosine-associated pleiotropic effects of the 2 P2Y12 receptor antagonists on vascular function, systemic inflammation, and circulating endothelial progenitor cells (EPCs). Both ticagrelor and prasugrel have potent antiplatelet effects. However, only ticagrelor inhibits cellular uptake of adenosine. Using a randomized, crossover design with 10-week follow-up ticagrelor or prasugrel was administered to type 2 diabetic patients with non-ST-segment elevation acute coronary syndrome requiring stent implantation. A total of 62 patients underwent randomization in a 1:1 ratio to receive ticagrelor or prasugrel for 5 weeks followed by a direct cross over to the alternative treatment for 5 additional weeks. Brachial artery flow-mediated dilation, inflammatory markers, and number of circulating EPCs were compared. Improvement in brachial artery flow-mediated dilation was greater in the ticagrelor group (0.15 ± 0.19 mm vs. -0.03 ± 0.18 mm; p ticagrelor compared with prasugrel decreased interleukin 6 (-0.58 ± 0.43 pg/ml vs. -0.05 ± 0.24 pg/ml; p Ticagrelor compared with prasugrel significantly increased absolute numbers of circulating EPCs CD34+/KDR+ (42.5 ± 37.8 per μl vs. -28.2 ± 23.7 per μl; p ticagrelor significantly decreased inflammatory cytokines such as interleukin 6 and tumor necrosis factor alpha and increased circulating EPCs, contributing to improved arterial endothelial function in diabetic non-ST-segment elevation acute coronary syndrome patients. Thus, data support that pleiotropic effects of ticagrelor beyond its potent antiplatelet effects could contribute to additional clinical benefits. (Comparison of Ticagrelor vs. Prasugrel on Inflammation, Arterial Stiffness, Endothelial Function, and Circulating Endothelial Progenitor Cells in Diabetic Patients With Non-ST Elevation Acute Coronary Syndrome [NSTE-ACS] Requiring Coronary Stenting; NCT02487732). Copyright © 2017 American College of Cardiology Foundation. Published

  2. Acute Gain in Minimal Lumen Area Following Implantation of Everolimus-Eluting ABSORB Biodegradable Vascular Scaffolds or Xience Metallic Stents: Intravascular Ultrasound Assessment From the ABSORB II Trial.

    Science.gov (United States)

    Sotomi, Yohei; Ishibashi, Yuki; Suwannasom, Pannipa; Nakatani, Shimpei; Cho, Yun-Kyeong; Grundeken, Maik J; Zeng, Yaping; Tateishi, Hiroki; Smits, Pieter C; Barragan, Paul; Kornowski, Ran; Gershlick, Anthony H; Windecker, Stephan; van Geuns, Robert-Jan; Bartorelli, Antonio L; de Winter, Robbert J; Tijssen, Jan; Serruys, Patrick W; Onuma, Yoshinobu

    2016-06-27

    The study compared, by intravascular ultrasound (IVUS), acute gain (AG) at the site of the pre-procedural minimal lumen area (MLA) achieved by either the Absorb (Abbott Vascular, Santa Clara, California) scaffold or the Xience stent and identified the factors contributing to the acute performance of these devices. It is warranted that the acute performance of Absorb matches that of metallic stents; however, concern exists about acute expansion and lumen gain with the use of Absorb. Of a total of 501 patients (546 lesions) in the ABSORB II (ABSORB II Randomized Controlled Trial) randomized trial, 445 patients with 480 lesions were investigated by IVUS pre- and post-procedure. Comparison of MLA pre- and post-procedure was performed at the MLA site by matching pre- and post-procedural IVUS pullbacks. Lower AG on IVUS (lowest tertile) occurred more frequently in the Absorb arm than in the Xience arm (3.46 mm(2) vs. 4.27 mm(2), respectively; p < 0.001; risk ratio: 3.04; 95% confidence interval: 1.94 to 4.76). The plaque morphology at the MLA cross-section was not independently associated with IVUS acute gain. The main difference in AG in MLD by angiography was observed at the time of device implantation (Xience vs. Absorb, Δ+1.50 mm vs. Δ+1.23 mm, respectively), whereas the gain from post-dilation was similar between the 2 arms (Δ+0.16 mm vs. Δ+0.16 mm) when patients underwent post-dilation, although expected balloon diameter was smaller in the Absorb arm than in the Xience arm (p = 0.003) during post-dilation. At the site of the pre-procedural MLA, the increase of the lumen post-procedure was smaller in the Absorb-arm than in the Xience arm. To achieve equivalent AG to Xience, the implantation of Absorb may require more aggressive strategies at implantation, pre- and post-dilation than the technique used in the ABSORB II trial. (ABSORB II Randomized Controlled Trial [ABSORB II]; NCT01425281). Copyright © 2016 American College of Cardiology Foundation. Published

  3. 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 or r...... to cobalt-chromium bare-metal stents in this relevant, low-risk group of everyday patients. In addition, a comparison with similar BASKET patients will allow to estimate the impact of 12-versus 6-month dual antiplatelet therapy on these outcomes Udgivelsesdato: 2008/4......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...... or refute this hypothesis, we set up an 11-center 4-country prospective trial of 2260 consecutive patients treated with >= 3.0-mm stents only, randomized to receive Cypher (Johnson & Johnson, Miami Lakes, FL), Vision (Abbott Vascular, Abbott Laboratories, IL), or Xience stents (Abbott Vascular). Only...

  4. Comparison of closed-cell and hybrid-cell stent designs in carotid artery stenting: clinical and procedural outcomes

    Directory of Open Access Journals (Sweden)

    Ersan TatlI

    2017-05-01

    Full Text Available Introduction: Carotid artery stenting (CAS is a promising alternative to surgery in high-risk patients. However, the impact of stent cell design on outcomes in CAS is a matter of continued debate. Aim : To compare the periprocedural and clinical outcomes of different stent designs for CAS with distal protection devices. Material and methods : All CAS procedures with both closed- and hybrid-cell stents performed at our institution between February 2010 and December 2015 were analyzed retrospectively. Adverse events were defined as death, major stroke, minor stroke, transient ischemic attack and myocardial infarction. Periprocedural and 30-day adverse events and internal carotid artery (ICA vasospasm rates were compared between the closed-cell and hybrid-cell stent groups. Results : The study included 234 patients comprising 146 patients with a closed-cell stent (Xact stent, Abbott Vascular (mean age: 68.5 ±8.6; 67.1% male and 88 patients with a hybrid-cell stent (Cristallo Ideale, Medtronic (mean age: 67.2 ±12.8; 68.2% male. There was no significant difference between the groups with respect to periprocedural or 30-day adverse event rates. While there was no difference in terms of tortuosity index between the groups, there was a higher procedural ICA vasospasm rate in the closed-cell stent group (35 patients, 23% compared with the hybrid-cell stent group (10 patients, 11% (p = 0.017. Conclusions : The results of this study showed no significant difference in the clinical adverse event rates after CAS between the closed-cell stent group and the hybrid-cell stent group. However, procedural ICA vasospasm was more common in the closed-cell stent group.

  5. Long-term safety of an everolimus-eluting bioresorbable vascular scaffold and the cobalt-chromium XIENCE V stent in a porcine coronary artery model.

    Science.gov (United States)

    Otsuka, Fumiyuki; Pacheco, Erica; Perkins, Laura E L; Lane, Jennifer P; Wang, Qing; Kamberi, Marika; Frie, Michael; Wang, Jin; Sakakura, Kenichi; Yahagi, Kazuyuki; Ladich, Elena; Rapoza, Richard J; Kolodgie, Frank D; Virmani, Renu

    2014-06-01

    The Absorb everolimus-eluting bioresorbable vascular scaffold (Absorb) has shown promising clinical results; however, only limited preclinical data have been published. We sought to investigate detailed pathological responses to the Absorb versus XIENCE V (XV) in a porcine coronary model with duration of implant extending from 1 to 42 months. A total of 335 devices (263 Absorb and 72 XV) were implanted in 2 or 3 main coronary arteries of 136 nonatherosclerotic swine and examined by light microscopy, scanning electron microscopy, pharmacokinetics, and gel permeation chromatography analyses at various time points. Vascular responses to Absorb and XV were largely comparable at all time points, with struts being sequestered within the neointima. Inflammation was mild to moderate (with absence of inflammation at 1 month) for both devices, although the scores were greater in Absorb at 6 to 36 months. Percent area stenosis was significantly greater in Absorb than XV at all time points except at 3 months. The extent of fibrin deposition was similar between Absorb and XV, which peaked at 1 month and decreased rapidly thereafter. Histomorphometry showed expansile remodeling of Absorb-implanted arteries starting after 12 months, and lumen area was significantly greater in Absorb than XV at 36 and 42 months. These changes correlated with dismantling of Absorb seen after 12 months. Gel permeation chromatography analysis confirmed that degradation of Absorb was complete by 36 months. Absorb demonstrates comparable long-term safety to XV in porcine coronary arteries with mild to moderate inflammation. Although Absorb was associated with greater percent stenosis relative to XV, expansile remodeling was observed after 12 months in Absorb with significantly greater lumen area at ≥ 36 months. Resorption is considered complete at 36 months. © 2014 American Heart Association, Inc.

  6. Vascular Vertigo

    Directory of Open Access Journals (Sweden)

    Mazyar Hashemilar

    2017-02-01

    Full Text Available Vertigo is a common complaint in neurology and medicine. The most common causes of vertigo are benign paroxysmal positional vertigo, vestibular neuritis, Meniere’s disease, and vascular disorders. Vertigo of vascular origin is usually limited to migraine, transient ischemic attacks, and ischemic or hemorrhagic stroke. Vascular causes lead to various central or peripheral vestibular syndromes with vertigo. This review provides an overview of epidemiology and clinical syndromes of vascular vertigo. Vertigo is an illusion of movement caused by asymmetrical involvement of the vestibular system by various causes. Migraine is the most frequent vascular disorder that causes vertigo in all age groups. Vertigo may occur in up to 25% of patients with migraine. The lifetime prevalence of migrainous vertigo is almost 1%. Cerebrovascular disorders are estimated to account for 3% to 7% of patients with vertigo. Vestibular paroxysmia has been diagnosed in 1.8% to 4% of cases in various dizziness units. Vasculitic disorders are rare in the general population, but vertigo may be seen in almost up to 50% of patients with different vasculitic syndromes. Conclusions: Migraine, cerebrovascular disorders especially involving the vertebrobasilar territory, cardiocirculatory diseases, neurovascular compression of the eighth nerve, and vasculitis are vascular causes of vertigo syndromes.

  7. Immediate outcomes of eptifibatide therapy during intracoronary stent implantation.

    Science.gov (United States)

    Shariati, Hooman; Sanei, Hamid; Pourmoghadas, Ali; Salehizadeh, Leila; Amirpour, Afshin

    2016-01-01

    The objective of the present study was to assess the major immediate outcomes of eptifibatide therapy during intracoronary stent implantation. In an interventional study, patients undergoing percutaneous coronary intervention (PCI) were randomized into either the eptifibatide (n = 100) or the control (n = 107) group. In each group, demographic and clinical characteristics such as cardiac death, stent thrombosis (ST), myocardial infarction (MI), rates of target lesion and vessel revascularization, cerebral vascular accident (CVA), and emergency coronary artery bypass grafting (CABG) were recorded. The overall rates of major adverse events such as mortality, Stent thrombosis (ST), Myocardial Infarction (MI), target lesion revascularization (TLR), target vessel revascularization (TVR), CVA, and emergency CABG within 24 h after stent implantation were low and comparable between the two groups; P > 0.05 considered significant for all comparisons. There were no statistical differences between the clinical outcomes of groups administered with single-dose intracoronary eptifibatide and control groups among patients undergoing PCI during stent implantation.

  8. Dexamethasone-eluting stents for the prevention of in-stent restenosis: Evidence for a differential effect in insulin-dependent and non-insulin-dependent diabetic patients

    NARCIS (Netherlands)

    Hoeven, B.L. van der; Pires, N.M.M.; Warda, H.M.; Putter, H.; Quax, P.H.A.; Schalij, M.J.; Jukema, J.W.

    2008-01-01

    Diabetes mellitus (DM) is a strong predictor of in-stent restenosis. This may be due to a higher level of vascular inflammation. We hypothesized that diabetic patients will benefit from dexamethasone-eluting stents, since local inflammation and consequently neointimal growth are suppressed and no

  9. Biocompatibility of coronary stent materials: effect of electrochemical polishing

    Energy Technology Data Exchange (ETDEWEB)

    Scheerder, I. de [University Hospital Leuven (Belgium). Dept. of Cardiology; Sohier, J.; Froyen, L.; Humbeeck, J. van [Louvain Univ. (Belgium). Dept. of Metallurgy and Materials Engineering; Verbeken, E. [University Hospital Leuven (Belgium). Dept. of Pathology

    2001-02-01

    Percutaneous Transluminal Coronary Revascularization (PTCR) is now a widely accepted treatment modality for atherosclerotic coronary artery disease. Current multicenter randomized trials comparing PTCR with the more invasive Coronary Artery Bypass Grafting could not show long-term significant survival differences. During the last two decades progress has been made to further optimize PTCR. The most logic approach to treat atherosclerotic coronary narrowings is to remove the atherosclerotic material using especially developed devices. Several trials, however, could not show a significant beneficial outcome after use of these devices compared to plain old balloon angioplasty. Another approach was to implant a coronary prothesis (stent), scaffolding the diseased coronary artery after PTCA. This approach resulted in a decreased restenosis rate at follow-up. The beneficial effects of stenting, however, was not found to be related to the inhibition of the neointimal cellular proliferation after vascular injury, but simply to be the mechanical result of overstretching of the treated vessel segment. The most important remaining clinical problem after stenting remains the neointimal hyperplasia within the stent, resulting in a significant stent narrowing in 13 to 30% of patients. Further efforts to improve the clinical results of coronary stenting should focus on the reduction of this neointimal hyperplasia. Neointimal hyperplasia after stent implantation results from (1) a healting response to the injury caused by the stent implantation and (2) a foreign body response to the stent itself. Factors that seem to influence the neointimal hyperplastic response are genetic, local disease related, stent delivery related and stent related factors. Biocompatibilisation of coronary stents by looking for more biocompatible metal alloys, optimized surface characteristics and optimized stent designs should result in a better late patency. Furthermore drug eluting and radioactive stents

  10. Incidence and Potential Mechanism(s) of Post-Procedural Rise of Cardiac Biomarker in Patients With Coronary Artery Narrowing After Implantation of an Everolimus-Eluting Bioresorbable Vascular Scaffold or Everolimus-Eluting Metallic Stent

    DEFF Research Database (Denmark)

    Ishibashi, Yuki; Muramatsu, Takashi; Nakatani, Shimpei

    2015-01-01

    OBJECTIVES: This study sought to evaluate the mechanism of post-procedural cardiac biomarker (CB) rise following device implantation. BACKGROUND: A fully bioresorbable Absorb scaffold, compared with everolimus-eluting metallic stents (EES), might be associated with a higher incidence of periproce......OBJECTIVES: This study sought to evaluate the mechanism of post-procedural cardiac biomarker (CB) rise following device implantation. BACKGROUND: A fully bioresorbable Absorb scaffold, compared with everolimus-eluting metallic stents (EES), might be associated with a higher incidence...

  11. Nickel-free stainless steel avoids neointima formation following coronary stent implantation

    Science.gov (United States)

    Fujiu, Katsuhito; Manabe, Ichiro; Sasaki, Makoto; Inoue, Motoki; Iwata, Hiroshi; Hasumi, Eriko; Komuro, Issei; Katada, Yasuyuki; Taguchi, Tetsushi; Nagai, Ryozo

    2012-12-01

    SUS316L stainless steel and cobalt-chromium and platinum-chromium alloys are widely used platforms for coronary stents. These alloys also contain nickel (Ni), which reportedly induces allergic reactions in some subjects and is known to have various cellular effects. The effects of Ni on neointima formation after stent implantation remain unknown, however. We developed coronary stents made of Ni-free high-nitrogen austenitic stainless steel prepared using a N2-gas pressurized electroslag remelting (P-ESR) process. Neointima formation and inflammatory responses following stent implantation in porcine coronary arteries were then compared between the Ni-free and SUS316L stainless steel stents. We found significantly less neointima formation and inflammation in arteries implanted with Ni-free stents, as compared to SUS316L stents. Notably, Ni2+ was eluted into the medium from SUS316L but not from Ni-free stainless steel. Mechanistically, Ni2+ increased levels of hypoxia inducible factor protein-1α (HIF-1α) and its target genes in cultured smooth muscle cells. HIF-1α and their target gene levels were also increased in the vascular wall at SUS316L stent sites but not at Ni-free stent sites. The Ni-free stainless steel coronary stent reduces neointima formation, in part by avoiding activation of inflammatory processes via the Ni-HIF pathway. The Ni-free-stainless steel stent is a promising new coronary stent platform.

  12. Nickel-free stainless steel avoids neointima formation following coronary stent implantation

    Science.gov (United States)

    Fujiu, Katsuhito; Manabe, Ichiro; Sasaki, Makoto; Inoue, Motoki; Iwata, Hiroshi; Hasumi, Eriko; Komuro, Issei; Katada, Yasuyuki; Taguchi, Tetsushi; Nagai, Ryozo

    2012-01-01

    SUS316L stainless steel and cobalt–chromium and platinum–chromium alloys are widely used platforms for coronary stents. These alloys also contain nickel (Ni), which reportedly induces allergic reactions in some subjects and is known to have various cellular effects. The effects of Ni on neointima formation after stent implantation remain unknown, however. We developed coronary stents made of Ni-free high-nitrogen austenitic stainless steel prepared using a N2-gas pressurized electroslag remelting (P-ESR) process. Neointima formation and inflammatory responses following stent implantation in porcine coronary arteries were then compared between the Ni-free and SUS316L stainless steel stents. We found significantly less neointima formation and inflammation in arteries implanted with Ni-free stents, as compared to SUS316L stents. Notably, Ni2+ was eluted into the medium from SUS316L but not from Ni-free stainless steel. Mechanistically, Ni2+ increased levels of hypoxia inducible factor protein-1α (HIF-1α) and its target genes in cultured smooth muscle cells. HIF-1α and their target gene levels were also increased in the vascular wall at SUS316L stent sites but not at Ni-free stent sites. The Ni-free stainless steel coronary stent reduces neointima formation, in part by avoiding activation of inflammatory processes via the Ni-HIF pathway. The Ni-free-stainless steel stent is a promising new coronary stent platform. PMID:27877545

  13. Endoscopic ultrasonography-guided placement of a transhepatic portal vein stent in a live porcine model

    OpenAIRE

    Park, Tae Young; Seo, Dong Wan; Kang, Hyeon-Ji; Cho, Min Keun; Song, Tae Jun; Park, Do Hyun; Lee, Sang Soo; Lee, Sung Koo; Kim, Myung-Hwan

    2016-01-01

    Background and Objectives: Percutaneous portal vein (PV) stent placement is used to manage PV occlusion or stenosis caused by malignancy. The use of endoscopic ultrasonography (EUS) has expanded to include vascular interventions. The aim of this study was to examine the technical feasibility and safety of EUS-guided transhepatic PV stent placement in a live porcine model. Materials and Methods: EUS-guided transhepatic PV stent placement was performed in six male miniature pigs under general a...

  14. RX Herculink Elite® renal stent system: a review of its use for the treatment of renal artery stenosis

    Directory of Open Access Journals (Sweden)

    Colyer Jr

    2012-08-01

    Full Text Available William R Colyer JrDivision of Cardiovascular Medicine, University of Toledo Medical Center, Toledo, OH, USAAbstract: The management of renal artery stenosis (RAS remains controversial. While some evidence suggests that treatment with stent placement is beneficial, randomized trials have failed to demonstrate a significant benefit. Ongoing clinical trials should help to better define the role for stenting of RAS while avoiding limitations seen with earlier trials. When it comes to stenting for RAS, several stents have been used; however, many stents which have been used previously and which are still being used are biliary stents that are used “off-label.” These stents have typically come onto the market through the 510(k pathway. To date, a total of five stents have been approved by the United States Food and Drug Administration for use in the renal arteries. Of the five stents that have received approval, the Bridge™ Extra Support (Medtronic CardioVascular, Santa Rosa, CA and the Palmaz® (Cordis Corporation, Bridgewater, NJ stents are no longer available. Currently, the Express® SD (Boston Scientific, Natick, MA, Formula™ (Cook Medical, Bloomington, IN, and Herculink Elite® (Abbott Vascular, Santa Clara, CA stents are Food and Drug Administration approved and available for use. The Herculink Elite is the most recently approved of the renal stents, having received approval in late 2011. The Herculink Elite stent is the only cobalt chromium stent approved for use in the renal arteries. Although trial data are limited and direct comparisons among renal stents is not possible, the Herculink Elite stent has demonstrated good performance. Additionally, the design of the Herculink Elite offers some advantages that may translate into improved outcomes.Keywords: renal artery stenosis, stenting, FDA approval

  15. Magnetizable stent-grafts enable endothelial cell capture

    Science.gov (United States)

    Tefft, Brandon J.; Uthamaraj, Susheil; Harburn, J. Jonathan; Hlinomaz, Ota; Lerman, Amir; Dragomir-Daescu, Dan; Sandhu, Gurpreet S.

    2017-04-01

    Emerging nanotechnologies have enabled the use of magnetic forces to guide the movement of magnetically-labeled cells, drugs, and other therapeutic agents. Endothelial cells labeled with superparamagnetic iron oxide nanoparticles (SPION) have previously been captured on the surface of magnetizable 2205 duplex stainless steel stents in a porcine coronary implantation model. Recently, we have coated these stents with electrospun polyurethane nanofibers to fabricate prototype stent-grafts. Facilitated endothelialization may help improve the healing of arteries treated with stent-grafts, reduce the risk of thrombosis and restenosis, and enable small-caliber applications. When placed in a SPION-labeled endothelial cell suspension in the presence of an external magnetic field, magnetized stent-grafts successfully captured cells to the surface regions adjacent to the stent struts. Implantation within the coronary circulation of pigs (n=13) followed immediately by SPION-labeled autologous endothelial cell delivery resulted in widely patent devices with a thin, uniform neointima and no signs of thrombosis or inflammation at 7 days. Furthermore, the magnetized stent-grafts successfully captured and retained SPION-labeled endothelial cells to select regions adjacent to stent struts and between stent struts, whereas the non-magnetized control stent-grafts did not. Early results with these prototype devices are encouraging and further refinements will be necessary in order to achieve more uniform cell capture and complete endothelialization. Once optimized, this approach may lead to more rapid and complete healing of vascular stent-grafts with a concomitant improvement in long-term device performance.

  16. Cost-utility analysis of stenting versus endarterectomy in the International Carotid Stenting Study.

    Science.gov (United States)

    Morris, Stephen; Patel, Nishma V; Dobson, Joanna; Featherstone, Roland L; Richards, Toby; Luengo-Fernandez, Ramon; Rothwell, Peter M; Brown, Martin M

    2016-06-01

    The International Carotid Stenting Study was a multicenter randomized trial in which patients with symptomatic carotid artery stenosis were randomly allocated to treatment by carotid stenting or endarterectomy. Economic evidence comparing these treatments is limited and inconsistent. We compared the cost-effectiveness of stenting versus endarterectomy using International Carotid Stenting Study data. We performed a cost-utility analysis estimating mean costs and quality-adjusted life years per patient for both treatments over a five-year time horizon based on resource use data and utility values collected in the trial. Costs of managing stroke events were estimated using individual patient data from a UK population-based study (Oxford Vascular Study). Mean costs per patient (95% CI) were US$10,477 ($9669 to $11,285) in the stenting group (N = 853) and $9669 ($8835 to $10,504) in the endarterectomy group (N = 857). There were no differences in mean quality-adjusted life years per patient (3.247 (3.160 to 3.333) and 3.228 (3.150 to 3.306), respectively). There were no differences in adjusted costs between groups (mean incremental costs for stenting versus endarterectomy $736 (95% CI -$353 to $1826)) or adjusted outcomes (mean quality-adjusted life years gained -0.010 (95% CI -0.117 to 0.097)). The incremental net monetary benefit for stenting versus endarterectomy was not significantly different from zero at the maximum willingness to pay for a quality-adjusted life year commonly used in the UK. Sensitivity analyses showed little uncertainty in these findings. Economic considerations should not affect whether patients with symptomatic carotid stenosis undergo stenting or endarterectomy. © 2016 World Stroke Organization.

  17. Current status of the Xience V® everolimus-eluting coronary stent system

    NARCIS (Netherlands)

    Claessen, Bimmer E.; Caixeta, Adriano; Henriques, José P. S.; Piek, Jan J.

    2010-01-01

    The introduction of drug-eluting stents has led to a marked reduction of restenosis, which is a major limitation of percutaneous coronary intervention for coronary artery disease. The next-generation Xience V® (Abbott Vascular, CA, USA) everolimus-eluting stent was designed to address the

  18. Bronchoscopic guidance of endovascular stenting limits airway compression.

    Science.gov (United States)

    Ebrahim, Mohammad; Hagood, James; Moore, John; El-Said, Howaida

    2015-04-01

    Bronchial compression as a result of pulmonary artery and aortic arch stenting may cause significant respiratory distress. We set out to limit airway narrowing by endovascular stenting, by using simultaneous flexible bronchoscopy and graduated balloon stent dilatation, or balloon angioplasty to determine maximum safe stent diameter. Between August 2010 and August 2013, patients with suspected airway compression by adjacent vascular structures, underwent CT or a 3D rotational angiogram to evaluate the relationship between the airway and the blood vessels. If these studies showed close proximity of the stenosed vessel and the airway, simultaneous bronchoscopy and graduated stent re-dilation or graduated balloon angioplasty were performed. Five simultaneous bronchoscopy and interventional catheterization procedures were performed in four patients. Median age/weight was 33 (range 9-49) months and 14 (range 7.6-24) kg, respectively. Three had hypoplastic left heart syndrome, and one had coarctation of the aorta (CoA). All had confirmed or suspected left main stem bronchial compression. In three procedures, serial balloon dilatation of a previously placed stent in the CoA was performed and bronchoscopy was used to determine the safest largest diameter. In the other two procedures, balloon testing with simultaneous bronchoscopy was performed to determine the stent size that would limit compression of the adjacent airway. In all cases, simultaneous bronchoscopy allowed selection of an ideal caliber of the stent that optimized vessel diameter while minimizing compression of the adjacent airway. In cases at risk for airway compromise, flexible bronchoscopy is a useful tool to guide endovascular stenting. Maximum safe stent diameter can be determined without risking catastrophic airway compression. © 2014 Wiley Periodicals, Inc.

  19. Forming of magnesium alloy microtubes in the fabrication of biodegradable stents

    OpenAIRE

    Wang, Lixiao; Fang, Gang; Qian, Lingyun; Leeflang, Sander; Duszczyk, Jurek; Jie ZHOU

    2014-01-01

    Magnesium alloys have, in recent years, been recognized as highly promising biodegradable materials, especially for vascular stent applications. Forming of magnesium alloys into high-precision thin-wall tubes has however presented a technological barrier in the fabrication of vascular stents, because of the poor workability of magnesium at room temperature. In the present study, the forming processes, i.e., hot indirect extrusion and multi-pass cold drawing were used to fabricate seamless mic...

  20. [Very late drug-eluting stent thrombosis by stent fracture].

    Science.gov (United States)

    Cheaito, R; Tritar, A; Scemama, A; Ferrag, W; Goy, P; Haziza, F; Benamer, H

    2015-12-01

    The superiority of drug-eluting stents in reducing the risk of in-stent restenosis compared to bare-metal stents is no longer challenged. Nevertheless, the drug-eluting stents may carry long-term risk of late and very late stent thrombosis. The promoting factors of this complication are usually divided into three chapters depending on the patient, the procedure and the stent. Indeed, the literature has reported several parameters related to the stent itself, such as its length, the malapposition, its diameter, but also more rarely the occurrence of stent fracture. We present the case of a patient admitted for myocardial infarction after a very late thrombosis of Cypher drug-eluting stent four years after its implantation and related to stent fracture. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

  1. 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.

  2. [Esophageal stenting complications].

    Science.gov (United States)

    Smoliar, A N; Radchenko, Iu A; Nefedova, G A; Abakumov, M M

    2014-01-01

    The aim of the study was to analyze esophageal stenting complications in case of cancer and benign diseases. It was investigated complications in 8 patients in terms from 7 days to 1 year after intervention. In 4 patients esophageal stenting was performed for constrictive esophageal cancer and compression with pulmonary cancer metastases into mediastinal lymphatic nodes. 2 patients had esophageal stenting for post-tracheostomy tracheo-esophageal fistula, 1 patient - for spontaneous esophageal rupture, 1 patient - for post-burn scar narrowing of esophagus and output part of the stomach. Severe patients' condition with tumor was determined by intensive esophageal bleeding in 2 cases, bilateral abscessed aspiration pneumonia, tumor bleeding, blood aspiration (1 case), posterior mediastinitis (1 case). Severe patients' condition with benign disease was associated with decompensated esophageal narrowing about proximal part of stent (1 case), increase of tracheo-esophageal fistula size complicated by aspiration pneumonia (1 case), stent migration into stomach with recurrence of esophago-mediastino-pleural fistula and pleural empyema (1 case), decompensated narrowing of esophagus and output part of the stomach (1 case). Patients with cancer died. And patients with benign diseases underwent multi-stage surgical treatment and recovered. Stenting is palliative method for patients with esophageal cancer. Patients after stenting should be under outpatient observation for early diagnosis of possible complications. Esophageal stenting in patients with benign diseases should be performed only by life-saving indications, in case of inability of other treatment and for the minimum necessary period.

  3. Characteristics of duplex sonographic parameters over time after successful carotid artery stenting.

    Science.gov (United States)

    Kim, Esther S H; Sun, Zhiyuan; Kapadia, Samir; Bajzer, Christopher; Arrigain, Susana; Gornik, Heather L

    2012-08-01

    Carotid duplex sonography is the primary tool for surveillance after carotid artery stenting, but the course of sonographic velocities over time after successful stenting is unclear. The purpose of this study was to describe carotid duplex sonographic velocity parameters after successful carotid artery stenting and to determine the predictors of poststent sonographic velocities. We queried institutional carotid stent and noninvasive vascular laboratory databases for internal carotid artery stents placed between January 2004 and June 2007. We included patients with stenosis of 20% or less on completion angiograms who had carotid duplex sonography within 30 days before and 7 days after stenting. The prestent peak systolic velocity (PSV), end-diastolic velocity (EDV), internal-to-common carotid artery PSV ratio, contralateral internal carotid artery velocities, stent type, open- versus closed-cell stent design, and days of follow-up were tested as potential predictors of poststent velocities. Eighty-two of 498 patients met inclusion criteria. The mean PSV and PSV ratio decreased from 423.6 cm/s and 7.1 before stenting to 98.5 cm/s and 1.3 after stenting (both P PSV, EDV, and PSV ratio) were dependent on prestent ipsilateral and contralateral velocities. The poststent EDV was dependent on the type of stent. The upper range for 0% to 20% stenosis in the stented internal carotid artery was a PSV of 141 cm/s, an EDV of 42 cm/s, and a PSV ratio of 2.1 or lower. With a median follow-up of 1 year, the PSV and PSV ratio remained stable over time in successfully stented carotid arteries. Deviations in sonographic parameters after initial poststent carotid duplex sonography should prompt an investigation for possible in-stent restenosis.

  4. In vivo evaluation of a biolimus eluting nickel titanium self expanding stent with overlapping balloon expandable drug eluting and bare metal stents in a porcine coronary model.

    Science.gov (United States)

    Cilingiroglu, Mehmet; Elliott, James; Sangi, Pramod; Matthews, Holly; Tio, Fermin; Trauthen, Brett; Elicker, John; Bailey, Steven R

    2009-01-01

    Long lesions and complex vessel anatomy frequently require the use of overlapping stents to treat a lesion. The purpose of this study was to evaluate the long-term effects of overlapping the Axxess Biolimus A9 eluting stent (BES) with two of the most commonly used, commercially available drug eluting stents. These stents were compared to BxVelocity bare metal (BMS) stents in a porcine coronary stent-injury model. Nineteen juvenile farm swine, 25-35 kg in weight, 3-6 months in age were utilised. Each animal received an Axxess stent to their coronary artery as permitted by the individual animal's anatomy. A second stent, either a Cypher, sirolimus eluting stent (SES) or, a Taxus, paclitaxel eluting stent (PES), or a BxVelocity bare metal stent (BMS) were implanted in an overlapped fashion. The animals were then followed for either 28 or 180 days as specified by a randomisation scheme. At the end of each follow-up period, they were euthenised, and the vessels containing the overlapping stents were harvested, processed into histological sections, and analysed. Compared to bare metal stents, overlapped segments using DES exhibited delayed vascular healing compared to both the proximal and distal non-overlap sites at each of the follow-up time point. Overall, in the non-overlap stent segments, SES induced significantly more inflammation and neointimal hyperplasia compared to PES and BMS. In this study of BMS and two different types of DES overlapped with the Axxess Biolimus A9 eluting stent, we found that while there was a delay in the degree of vascular healing with DES compared to BMS, the specific type of DES that was overlapped with BES did not affect the behaviour of the overlap zone in terms of most of the histomorphometric measures at 28 or 180 days. This was true whether the stent was drug eluting or bare metal. More inflammation with delayed healing was seen in the SES compared to PES and BMS.

  5. Stent intussusception after thromboaspiration through a platinum chrome stent: a particular case of longitudinal stent deformation.

    Science.gov (United States)

    Mila, Rafael; Vignolo, Gustavo; Trujillo, Pedro

    2015-04-01

    The need to improve stent deliverability has led to the development of thinner and more flexible stents. However, there is concern about decreased longitudinal strength. The number of longitudinal stent deformation reports has dramatically increased. We report a case of stent longitudinal deformation after thromboaspiration through a new generation platinum chrome bare metal stent. Images show an "intussusception effect," an extreme form of the previously described "concertina deformation," as the mechanism of shortening. Since stent technology is constantly evolving, newer devices will probably be designed to have less susceptibility to longitudinal stent deformation.

  6. Late Silent Stent Abscess.

    Science.gov (United States)

    Zateyshchikov, Dmitry; Fattakhova, Elvira; Demchinsky, Vladimir; Baklanova, Tatiana; Serebruany, Victor

    2015-01-01

    Coronary stent infections in general and stent abscesses (SAs) in particular are rare but often deadly complications. Most SAs manifest with fever and chest pain within 30 days after intervention and require antibiotics and stent removal. A 45-year-old man with second ST elevated myocardial infarction and cardiogenic shock was admitted to a hospital that had no cardiac catheterization laboratory. The patient underwent fibrinolytic therapy with alteplase but died 1 h later. His medical history revealed posterior myocardial infarction 7 years before, which had been successfully treated with a bare metal stent of the right coronary artery. The post-discharge observation had been unremarkable with no evidence of ischaemia or infection but gross non-compliance. Autopsy revealed complete closure of the left main coronary artery and a surprise additional finding, namely SA; the stented portion of the artery was enveloped by an abscess, and purulent material completely occluded the stent, which was floating in pus. Impressions: Since coronary angioplasty is so common, the incidence of late silent SA is probably higher than expected, especially considering that there is often a lack of clinical manifestations. Clinicians should be cognizant of this complication. More attention may be required to assess the condition of existing stents during repeated interventions. Gross non-compliance and/or early withdrawal from dual anti-platelet therapy may be directly responsible for the development of silent delayed SA.

  7. Biodegradable intestinal stents: A review

    Directory of Open Access Journals (Sweden)

    Zhanhui Wang

    2014-10-01

    Full Text Available Biodegradable stents are an attractive alternative to self-expanding metal stents in the treatment of intestinal strictures. Biodegradable stent can be made of biodegradable polymers and biodegradable metals (magnesium alloys. An overview on current biodegradable intestinal stents is presented. The future trends and perspectives in the development of biodegradable intestinal stents are proposed. For the biodegradable polymer intestinal stents, the clinical trials have shown promising results, although improved design of stents and reduced migration rate are expected. For the biodegradable magnesium intestinal stents, results of preliminary studies indicate magnesium alloys to have good biocompatibility. With many of the key fundamental and practical issues resolved and better methods for adjusting corrosion resistance and progressing biocompatibilities of magnesium alloys, it is possible to use biodegradable intestinal stents made of magnesium alloys in hospital in the not too distant future.

  8. Angiographic results of the cobalt chromium Vision and Mini-Vision stents.

    Science.gov (United States)

    Wöhrle, Jochen; Nusser, Thorsten; Hoffmann, Stephanie; Kochs, Matthias

    2009-10-01

    Drug-eluting stents (DES) have been shown to reduce repeat revascularizations compared with their bare-metal stent (BMS) platforms. Modern BMS may be associated with better angiographic results compared with the older BMS platforms. In the Basel Stent Kosten Effektivitats Trial (BASKET), target vessel revascularization after six months was nonsignificantly different between DES and BMS with clinical follow-up. To evaluate angiographic results of the cobalt chromium Vision and Mini-Vision stents (Abbott Vascular, USA). A total of 247 consecutive patients with 293 de novo lesions in native coronary arteries were treated with cobalt chromium Vision (n=184; stent diameter 2.75 mm to 4.0 mm) or Mini-Vision stents (n=109; stent diameter 2.0 mm to 2.5 mm), and scheduled for six months of angiographic follow-up. The primary end point was in-stent late loss after six months. Acute coronary syndromes were present in 83.4% (n=206) of patients. The preinterventional reference diameter of Vision stents was 2.70+/-0.34 mm and for Mini-Vision stents, it was 2.13+/-0.27 mm (Pstent late loss was 0.64+/-0.67 mm and the binary restenosis rate was 17.9%. In the Mini-Vision group, in-stent late loss was 0.82+/-0.71 mm and the restenosis rate was 45.4%. No difference in occurrence of restenosis within the segments proximal or distal to the stent was observed. The restenotic pattern was predominantly focal with a short length of 7.9+/-4.4 mm. The use of the cobalt chromium Vision stent for the treatment of de novo lesions was associated with a low late loss and binary angiographic restenosis rate.

  9. The benefits of drug-eluting stents in the treatment of coronary artery disease

    Directory of Open Access Journals (Sweden)

    Kiramijyan S

    2016-03-01

    Full Text Available Sarkis Kiramijyan,1 Ming W Liu2 1Division of Cardiology, Department of Medicine, Harbor-UCLA Medical Center, Torrance, CA, USA; 2Heart and Vascular Care Center, White Memorial Medical Center, Los Angeles, CA, USA Abstract: The advent of coronary stents has been a landmark development in the treatment of coronary artery disease with percutaneous coronary intervention. Initial percutaneous treatment using balloon angioplasty alone had limited clinical efficacy due to immediate vascular elastic recoil and dissection, in addition to late negative vascular remodeling and neointimal hyperplasia. With the introduction of coronary stents, initially bare-metal stents (BMS, the problems of dissection and negative remodeling due to injury in addition to vascular elastic recoil were eliminated; however, neointimal hyperplasia remained an ongoing obstacle in the long-term efficacy of stents. Neointimal hyperplasia resulted in in-stent restenosis in 20%–30% of cases after intervention with BMS, which led to high rates of target lesion revascularization. Subsequently, drug-eluting stents (DES were introduced, which had the added advantage of releasing an anti-proliferative drug from the stent to reduce the neointimal proliferation, thus resulting in the reduction of the rates of in-stent restenosis. Although the first-generation DES had significantly improved outcomes over its predecessor, the BMS, several challenges including stent thrombosis and delayed endothelialization of the stent remained. The second-generation DES have been significantly improved over their first-generation predecessors in regard to efficacy and safety, ie, improved long-term outcomes and significant reductions in stent thrombosis. The duration of dual antiplatelet therapy after DES has also been studied extensively in multiple large trials. A newer generation of stents, including those with bioresorbable polymers, polymer-free, and fully bioresorbable scaffolds is still in the early

  10. What Is a Stent?

    Science.gov (United States)

    ... surgery or a fabric stent is used to repair an aneurysm in the abdominal aorta. These problems ... with clinical research. More Information Related Health Topics Aneurysm Carotid Artery Disease Coronary Heart Disease Percutaneous Coronary Intervention Peripheral Artery Disease ...

  11. Treatment of carotid artery aneurysms with covered stents; Aneurysmabehandlung der Arteria carotis interna mit gecoverten Stents

    Energy Technology Data Exchange (ETDEWEB)

    Rohr, A.; Alfke, K.; Doerner, L.; Jansen, O. [UKSH Kiel (Germany). Neurochirurgie Neuroradiologie; Bartsch, T.; Stingele, R. [UKSH Kiel (Germany). Neurologie

    2007-10-15

    Purpose: Evaluation of the use of covered stents in treating pseudoaneurysms of the cervical and intracranial/extradural carotid artery and determination of the periprocedural and short- to mid-term complication rate. Materials and Methods: 8 patients with 9 spontaneous dissecting aneurysms of the cervical carotid artery - 5 of which were symptomatic - plus one patient with ofthalmoplegia due to an aneurysm of the cavernous carotid artery were studied. While the latter was treated with a PTFE-covered balloon-mounted stainless steel stent (Jostent/Graftmaster), a self-expanding PTFE-covered Nitonol Stent (Symbiot) was used in all other cases. Intervention was performed with local anesthesia. Aspirin and Clopidogrel were both used as antiplatelet drugs. Clinical signs and symptoms and vascular imaging with DS, MR, CT angiography and ultrasound were recorded during patient follow-up, with a mean follow-up period of 14.6 months (4 - 30). Results: We were able to treat 8 out of 10 aneurysms (80 %) using covered stents. The aneurysms were immediately occluded and the associated stenoses of the parent vessel were eliminated. No clinically relevant complications occurred during the procedure or in the follow-up interval. In two cases, elongation of the carotid artery prevented the stent from being positioned over the aneurysm neck. These cases were shown to be stable with the use of antiplatelet drugs. Conclusion: Covered stents can be used in the treatment of pseudoaneurysms of the carotid artery as an alternative to long-term antithrombotic medication or surgery. In our study treatment was effective (80 %) and free of complications in the short- and mid-term follow-up. Possible indications, technique and the use of imaging modalities for patient follow-up are discussed. (orig.)

  12. The evolving impact of microfabrication and nanotechnology on stent design.

    Science.gov (United States)

    Caves, Jeffrey M; Chaikof, Elliot L

    2006-12-01

    Noncoronary atherosclerotic vascular disease, including symptomatic lower extremity peripheral arterial disease (PAD), promises to extract a steadily rising medical and economic toll over the coming decades. Although drug-eluting stents have led to substantial advances in the management of coronary atherosclerosis, endovascular treatment of noncoronary, peripheral arterial lesions continues to yield high restenosis rates and early clinical failures. In this report, we review recent developments in microfabrication and nanotechnology strategies that offer new opportunities for improving stent-based technology for the treatment of more extensive and complex lesions. In this regard, stents with microfabricated reservoirs for controlled temporal and spatial drug release have already been successfully applied to coronary lesions. Microfabricated needles to pierce lesions and deliver therapeutics deep within the vascular wall represent an additional microscale approach. At the nanoscale, investigators have primarily sought to alter the strut surface texture or coat the stent to enhance inductive or conductive schemes for endothelialization and host artery integration. Nanotechnology research that identifies promising strategies to limit restenosis through targeted drug delivery after angioplasty and stenting is also reviewed.

  13. An automatic algorithm for detecting stent endothelialization from volumetric optical coherence tomography datasets

    Energy Technology Data Exchange (ETDEWEB)

    Bonnema, Garret T; Barton, Jennifer K [College of Optical Sciences, University of Arizona, Tucson, AZ (United States); Cardinal, Kristen O' Halloran [Biomedical and General Engineering, California Polytechnic State University (United States); Williams, Stuart K [Cardiovascular Innovation Institute, University of Louisville, Louisville, KY 40292 (United States)], E-mail: barton@u.arizona.edu

    2008-06-21

    Recent research has suggested that endothelialization of vascular stents is crucial to reducing the risk of late stent thrombosis. With a resolution of approximately 10 {mu}m, optical coherence tomography (OCT) may be an appropriate imaging modality for visualizing the vascular response to a stent and measuring the percentage of struts covered with an anti-thrombogenic cellular lining. We developed an image analysis program to locate covered and uncovered stent struts in OCT images of tissue-engineered blood vessels. The struts were found by exploiting the highly reflective and shadowing characteristics of the metallic stent material. Coverage was evaluated by comparing the luminal surface with the depth of the strut reflection. Strut coverage calculations were compared to manual assessment of OCT images and epi-fluorescence analysis of the stented grafts. Based on the manual assessment, the strut identification algorithm operated with a sensitivity of 93% and a specificity of 99%. The strut coverage algorithm was 81% sensitive and 96% specific. The present study indicates that the program can automatically determine percent cellular coverage from volumetric OCT datasets of blood vessel mimics. The program could potentially be extended to assessments of stent endothelialization in native stented arteries.

  14. A novel electrical potential sensing method for in vitro stent fracture monitoring and detection.

    Science.gov (United States)

    Park, Chan-Hee; Tijing, Leonard D; Yun, Yeoheung; Kim, Cheol Sang

    2011-01-01

    This article describes a preliminary investigation and prototype fabrication of a novel potential sensing method to continuously monitor vascular stent fractures. A potential measurement system consisting of Wheatstone bridge circuit and signal conditioning circuit was designed for the cardiovascular stent durability and fatigue test. Each end of a bare and polyurethane-covered Nitinol vascular stent was electrically connected to the potential measurement system and then immersed either in simulated body fluid (SBF) media or distilled water at 36.4 ± 1 °C. When the stent experienced fracture (i.e., a cut), its electrical potential decreased with an increase in electrical resistance. This method successfully measured fractures in the stent regardless of location. Furthermore, the number of cycles at the onset of stent fracture was accurately detected and continuously monitored using this technique. Thus, the present fracture detection method, which to our knowledge is the first ever report to use electrical potential measurement for stent durability test, gives a fast, real-time, accurate and efficient detection of fractures in stent during in vitro fatigue and durability test.

  15. Wave reflection and transmission in multiply stented blood vessels

    Science.gov (United States)

    Papathanasiou, T. K.; Movchan, A. B.; Bigoni, D.

    2017-06-01

    Closed circulatory systems display an exquisite balance between vascular elasticity and viscous fluid effects, to induce pulse-smoothing and avoid resonance during the cardiac cycle. Stents in the arterial tree alter this balance through stiffening and because a periodic structure is introduced, capable of interacting with the fluid in a complex way. While the former feature has been investigated, the latter received no attention so far. But periodic structures are the building blocks of metamaterials, known for their `non-natural' behaviour. Thus, the investigation of a stent's periodic microstructure dynamical interactions is crucial to assess possible pathological responses. A one-dimensional fluid-structure interaction model, simple enough to allow an analytical solution for situations of interest involving one or two interacting stents, is introduced. It is determined: (i) whether or not frequency bands exist in which reflected blood pulses are highly increased and (ii) if these bands are close to the characteristic frequencies of arteries and finally, (iii) if the internal structure of the stent can sensibly affect arterial blood dynamics. It is shown that, while the periodic structure of an isolated stent can induce anomalous reflection only in pathological conditions, the presence of two interacting stents is more critical, and high reflection can occur at frequencies not far from the physiological values.

  16. 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.

  17. 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.

  18. Delayed ischemic stroke due to stent marker band occlusion after stent-assisted coiling.

    Science.gov (United States)

    Kawabata, Shuhei; Imamura, Hirotoshi; Suzuki, Keita; Tani, Shoichi; Adachi, Hidemitsu; Sakai, Nobuyuki

    2017-11-03

    A middle-aged patient with an internal carotid-posterior communicating artery aneurysm and basilar artery tip aneurysm was treated by stent-assisted coiling. One ischemic infarction and two transient ischemic attacks occurred with the same symptoms (inability to walk unassisted and tendency to fall to the left) during the first 2 years post-treatment. The ischemic infarction was found in the right side of the pons, consistent with the vascular territory of the stent-containing vessel. The cause of the delayed ischemic stroke was investigated on DSA and cone beam CT, which revealed that the proximal end of the stent, one marker band, was just covering a small perforating artery of the basilar artery trunk. The present case suggests that marker band occlusion can induce delayed ischemic stroke. To prevent this complication, it is important to evaluate the perforating vessels preoperatively and carefully deploy a stent for the marker band to avoid occlusion of large perforating vessels. Post-treatment evaluation is also important because dual antiplatelet therapy will be required for a longer period if an artery is occluded by a marker band. © BMJ Publishing Group Ltd (unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

  19. Eosinophilic responses to stent implantation and the risk of Kounis hypersensitivity associated coronary syndrome.

    Science.gov (United States)

    Kounis, Nicholas G; Giannopoulos, Sotiris; Tsigkas, Grigorios G; Goudevenos, John

    2012-04-19

    The use of drug eluting stents constitutes a major breakthrough in current interventional cardiology because it is more than halves the need of repeat interventions. It is incontrovertible that coronary stents, in general, have been beneficial for the vast majority of patients. A small increase in thrombosis, following DES implantation, is offset by a diminished risk of complications associated with repeat vascularization. However, late and, especially, very late stent thrombosis is a much feared complication because it is associated with myocardial infarction with increased mortality. Despite that stent thrombosis is thought to be multifactorial, so far clinical reports and reported pathology findings in patients died from coronary stent thrombosis as well as animal studies and experiments, point toward a hypersensitivity inflammation. The stented and thrombotic areas are infiltrated by interacting, via bidirectional stimuli inflammatory cells including eosinophils, macrophages, T-cells and mast cells. Stented regions constitute an ideal surrounding for endothelial damage and dysfunction, together with hemorheologic changes and turbulence as well as platelet dysfunction, coagulation and fibrinolytic disturbances. Drug eluting stent components include the metal strut which contains nickel, chromium, manganese, titanium, molybdenum, the polymer coating and the impregnated drugs which for the first generation stents are: the antimicrotubule antineoplastic agent paclitaxel and the anti-inflammatory, immunosuppressive and antiproliferative agent sirolimus. The newer stents which are called cobalt-chromiun stents and elute the sirolimus analogs everolimus and zotarolimus both contain nickel and other metals. All these components constitute an antigenic complex inside the coronary arteries which apply chronic, continuous, repetitive and persistent inflammatory action capable to induced Kounis syndrome and stent thrombosis. Allergic inflammation goes through three phases

  20. Successful Endobronchial stenting for bronchial compression from a massive thoracic aortic aneurysm

    Directory of Open Access Journals (Sweden)

    David Comer

    2010-06-01

    Full Text Available A case of bronchial occlusion caused by a thoracic aortic aneurysm and the relief of this obstruction by the implantation of expandable metallic stents is described. Stent deployment provided an immediate improvement in lung ventilation and chest radiograph appearances. Stent insertion was uncomplicated, but weaning from mechanical ventilation was unsuccessful and the patient died from a ventilator-associated pneumonia, unrelated to the procedure. Endobronchial stenting should be considered as a non-invasive therapy for the treatment of bronchial obstruction, with respiratory compromise, caused by a thoracic aortic aneurysm when vascular surgery is not an option. The medium to long term survival of this patient group is poor. This can be attributed to complications related to the stent and also to the poor performance status of these patients.

  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

    Aims: Data are limited on the prognostic impact of stent thrombosis and in-stent restenosis in patients treated with coronary stents. We examined the prognostic impact of stent thrombosis and in-stent restenosis in patients treated with percutaneous coronary intervention (PCI). Methods and result...

  2. Successful technical and clinical outcome using a second generation balloon expandable coronary stent for transplant renal artery stenosis: Our experience

    Science.gov (United States)

    Salsamendi, Jason; Pereira, Keith; Baker, Reginald; Bhatia, Shivank S; Narayanan, Govindarajan

    2015-01-01

    Transplant renal artery stenosis (TRAS) is a vascular complication frequently seen because of increase in the number of renal transplantations. Early diagnosis and management is essential to optimize a proper graft function. Currently, the endovascular treatment of TRAS using angioplasty and/or stenting is considered the treatment of choice with the advantage that it does not preclude subsequent surgical correction. Treatment of TRAS with the use of stents, particularly in tortuous transplant renal anatomy presents a unique challenge to an interventional radiologist. In this study, we present three cases from our practice highlighting the use of a balloon-expandable Multi-Link RX Ultra coronary stent system (Abbott Laboratories, Abbott Park, Illinois, USA) for treating high grade focal stenosis along very tortuous renal arterial segments. Cobalt–Chromium alloy stent scaffold provides excellent radial force, whereas the flexible stent design conforms to the vessel course allowing for optimal stent alignment. PMID:26629289

  3. Successful technical and clinical outcome using a second generation balloon expandable coronary stent for transplant renal artery stenosis: Our experience.

    Science.gov (United States)

    Salsamendi, Jason; Pereira, Keith; Baker, Reginald; Bhatia, Shivank S; Narayanan, Govindarajan

    2015-10-01

    Transplant renal artery stenosis (TRAS) is a vascular complication frequently seen because of increase in the number of renal transplantations. Early diagnosis and management is essential to optimize a proper graft function. Currently, the endovascular treatment of TRAS using angioplasty and/or stenting is considered the treatment of choice with the advantage that it does not preclude subsequent surgical correction. Treatment of TRAS with the use of stents, particularly in tortuous transplant renal anatomy presents a unique challenge to an interventional radiologist. In this study, we present three cases from our practice highlighting the use of a balloon-expandable Multi-Link RX Ultra coronary stent system (Abbott Laboratories, Abbott Park, Illinois, USA) for treating high grade focal stenosis along very tortuous renal arterial segments. Cobalt-Chromium alloy stent scaffold provides excellent radial force, whereas the flexible stent design conforms to the vessel course allowing for optimal stent alignment.

  4. Efectos biológicos de los stents medicados en la circulación coronaria Biological effects of drug-eluting stents in the coronary circulation

    Directory of Open Access Journals (Sweden)

    Darío Echeverri

    2010-04-01

    Full Text Available Los stents medicados ofrecen la mejor alternativa disponible no quirúrgica para el tratamiento de la enfermedad coronaria gracias a su demostrada eficacia. Sin embargo, estos excelentes resultados han sido opacados en términos de seguridad, principalmente por la presencia de trombosis de stents de manera tardía o muy tardía. La comprensión de los efectos biológicos que ejercen a nivel de la arteria coronaria luego de su implante, se debe al efecto de la plataforma utilizada, el polímero y la droga que liberan. Los trastornos de reparación vascular inducidos favorecen la trombosis de stents y sus consecuencias clínicas. Se hace una revisión de los diferentes efectos biológicos de los stents medicados en las arterias coronarias, que permite comprender como han surgido rápidamente nuevas versiones en materiales, diseños, polímeros y medicamentos que reducen los efectos adversos a nivel coronario, mejorando su eficacia y seguridad.Drug-eluting stents offer the best available non-surgical alternative for the treatment of coronary disease, thanks to its demonstrated efficacy. However, in terms of security, these excellent results have been overshadowed by the late or very late appearance of stent thromboses.The biological effects they have in the coronary artery after its implantation are due to the effect of the platform used, the polymer and the medication released. The vascular healing disorders induced by drug-eluting stents favor stent thrombosis and its clinical consequences. This is a review of the different biological effects of drug-eluting stents in coronary arteries that allows to understand how the rapid onset of new versions of materials, designs, polymers and medications diminish adverse coronary effects and improve its efficacy and safety.

  5. 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

    2012-01-01

    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...

  6. Using COMSOL Multiphysics for Biomechanical Analysis of Stent Technology in Cerebral Aneurysms

    OpenAIRE

    Rasmussen, Joachim; Thyregod, Jesper; Enevoldsen, Marie Sand; Henneberg, Kaj-Åge

    2009-01-01

    This work presents new fluid-structure interaction (FSI) models in both 2D and 3D of the effect of using vascular stents as treatment of cerebral berry aneurysms. The stent is positioned inside the cerebral artery covering the neck of the aneurysm. The stent is expected to alter the blood flow into the aneurysm such that the blood coagulates due to low blood velocity, and rupture of the aneurysm is prevented. A 3D FSI model consisting of three domains (blood, arterial, and aneurismal) is used...

  7. Asymmetric Ashes

    Science.gov (United States)

    2006-11-01

    that oscillate in certain directions. Reflection or scattering of light favours certain orientations of the electric and magnetic fields over others. This is why polarising sunglasses can filter out the glint of sunlight reflected off a pond. When light scatters through the expanding debris of a supernova, it retains information about the orientation of the scattering layers. If the supernova is spherically symmetric, all orientations will be present equally and will average out, so there will be no net polarisation. If, however, the gas shell is not round, a slight net polarisation will be imprinted on the light. This is what broad-band polarimetry can accomplish. If additional spectral information is available ('spectro-polarimetry'), one can determine whether the asymmetry is in the continuum light or in some spectral lines. In the case of the Type Ia supernovae, the astronomers found that the continuum polarisation is very small so that the overall shape of the explosion is crudely spherical. But the much larger polarization in strongly blue-shifted spectral lines evidences the presence, in the outer regions, of fast moving clumps with peculiar chemical composition. "Our study reveals that explosions of Type Ia supernovae are really three-dimensional phenomena," says Dietrich Baade. "The outer regions of the blast cloud is asymmetric, with different materials found in 'clumps', while the inner regions are smooth." "This study was possible because polarimetry could unfold its full strength thanks to the light-collecting power of the Very Large Telescope and the very precise calibration of the FORS instrument," he adds. The research team first spotted this asymmetry in 2003, as part of the same observational campaign (ESO PR 23/03 and ESO PR Photo 26/05). The new, more extensive results show that the degree of polarisation and, hence, the asphericity, correlates with the intrinsic brightness of the explosion. The brighter the supernova, the smoother, or less clumpy

  8. VASCULAR DEMENTIA

    Directory of Open Access Journals (Sweden)

    Maria Alekseyevna Cherdak

    2010-01-01

    vascular cognitive disorders and vascular dementia (VD. The heterogeneity of vascular cognitive disorders, concurrence of vascular and neurodegenerative diseases are discussed. Data from studies of specific therapy for VD are given.

  9. Mechanical properties and in vivo performance of a novel sliding-lock bioabsorbable poly-p-dioxanone stent.

    Science.gov (United States)

    Feng, Qimao; Jiang, Wenbo; Sun, Kun; Sun, Kang; Chen, Sun; Zhao, Lijiao; Dai, Ke; Ma, Ning

    2011-10-01

    A bioabsorbable poly-p-dioxanone (PPDO) stent with a novel sliding-lock structure was fabricated to treat stenotic peripheral vessels. The sliding-lock PPDO stents have greater radial strength (107 kPa) than PPDO stents with conventional net-tube structure (32 kPa). The sliding-lock PPDO stents were implanted into the iliac arteries of pigs, and implantation success rate was 90% indicating the feasibility of this design. Additionally, we found that sliding-lock PPDO stents kept vessels patent, although by 3 and 6 months post implantation, luminal diameter decreased slightly due to intimal hyperplasia. At 1 month post implantation, the stents were sparsely covered with endothelial cells, and by 6 months, the stents were mostly absorbed and inflammatory reaction gradually decreased as the stents were absorbed. This study shows favorable mechanical strength, degradability and efficacy for the sliding-lock PPDO stents, and supports further research and development of this unique design of polymer stents for applications in vascular devices.

  10. Auxetic coronary stent endoprosthesis

    DEFF Research Database (Denmark)

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

    2014-01-01

    was obtained via laser cutting, and surface treatment was performed with acid pickling and electropolishing, followed by an annealing process. In vitro mechanical analysis was performed to analyze the mechanical performance of the auxetic coronary stent. Scanning electronic microscopy (SEM) was used...

  11. Hemodynamic comparison of stent configurations used for aortoiliac occlusive disease.

    Science.gov (United States)

    Groot Jebbink, Erik; Mathai, Varghese; Boersen, Johannes T; Sun, Chao; Slump, Cornelis H; Goverde, Peter C J M; Versluis, Michel; Reijnen, Michel M P J

    2017-07-01

    . The CERAB configuration is the most unimpaired physiologic reconstruction, whereas BMK and CK stents have their typical zones of flow recirculation. Copyright © 2016 Society for Vascular Surgery. Published by Elsevier Inc. All rights reserved.

  12. Late in-stent thrombosis following carotid angioplasty and stenting.

    Science.gov (United States)

    Buhk, Jan-Hendrik; Wellmer, Andreas; Knauth, Michael

    2006-05-23

    Acute in-stent thrombosis is a well-known complication of carotid angioplasty and stenting (CAS) and often due to resistance to or inadequate treatment with platelet-inhibiting agents. The authors report three cases of a delayed in-stent thrombosis after more than a week but less than 3 months after CAS. In all cases, the postprocedural antiplatelet regimen was discontinued to enable the treatment of a relevant comorbidity.

  13. Primary angioplasty: Effect of deferred stenting on stent size.

    Science.gov (United States)

    Harbaoui, Brahim; Emsellem, Philippe; Cassar, Emmanuel; Besnard, Cyril; Dauphin, Raphael; Motreff, Pascal; Courand, Pierre-Yves; Lantelme, Pierre

    2017-04-01

    Primary angioplasty with immediate stenting (IS) is the gold standard for ST-segment elevation myocardial infarction (STEMI). Deferred stenting (DS) has been proposed to limit periprocedural complications, and may influence stent size because of thrombus and spasm alleviation. We sought to study the effect of DS on stent size. Over the study period, 258 patients underwent primary angioplasty for STEMI (DS, n=84; IS, n=174). An informative coronary angiogram run - i.e. allowing for proper lesion analysis - was selected and anonymized by an independent operator. Two experienced operators randomly analysed these runs, and proposed stent dimensions after having measured vessel diameter and lesion length by quantitative coronary analysis. The primary objective was the variation in stent size between the two coronary angiograms. The median delay between the two coronary angiograms was 2 days. Overall, the stent length was shorter (-1.64mm; P=0.030) and its diameter was larger (+0.13mm; P<0.001) during the second coronary angiogram, especially in the right coronary arteries. DS led to the implantation of a larger and shorter stent; this is probably because DS allows for more accurate assessment of the residual lesion after relief of spasm and thrombus, and may have clinical consequences in terms of stent thrombosis and restenosis. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  14. Clinical and economic studies of eptifibatide in coronary stenting

    OpenAIRE

    Pasala T; Sattayaprasert P; Bhat PK; Athappan G; Gandhi S

    2014-01-01

    Tilak Pasala, Prasongchai Sattayaprasert, Pradeep K Bhat, Ganesh Athappan, Sanjay Gandhi The Heart and Vascular Center, Case Western Reserve University/MetroHealth, Cleveland, OH, USA Abstract: Platelet adhesion and aggregation at the site of coronary stenting can have catastrophic clinical and economic consequences. Therefore, effective platelet inhibition is vital during and after percutaneous coronary intervention. Eptifibatide is an intravenous antiplatelet agent that blocks the final co...

  15. TIDES-ACS Trial: comparison of titanium-nitride-oxide coated bio-active-stent to the drug (everolimus)-eluting stent in acute coronary syndrome. Study design and objectives.

    Science.gov (United States)

    Colkesen, E B; Eefting, F D; Rensing, B J; Suttorp, M J; Ten Berg, J M; Karjalainen, P P; Van Der Heyden, J A

    2015-02-01

    Drug-eluting stents (DES), delivering antiproliferative drugs from a durable polymer, have shown to reduce in-stent restenosis after percutaneous coronary intervention (PCI) compared to bare-metal stents (BMS). However, they have been associated with a hypersensitivity reaction, delayed healing, and incomplete endothelialization, which may contribute to an increased risk of late stent thrombosis. Consequently, a prolonged duration of dual antiplatelet therapy (DAPT) is needed, with an increased risk of bleeding complication. A number of stent technologies are being developed in an attempt to modify late thrombotic events and DAPT duration. The Optimax™ stent is such a novel, next generation bioactive stent (BAS), in which a thicker layer of titanium-nitride-oxide coating is inserted over the stent struts. The rationale of this is to obtain more efficient and rapid vascular healing at the site of the stent implantation. The aim of TIDES-ACS Trial is to compare clinical outcome in patients presenting with ACS, treated with PCI using Optimax-BAS versus Synergy™-EES. Second objective is to explore whether the Optimax™-BAS use is superior compared with Synergy™-EES use with respect of hard end points (cardiac death, myocardial infarction [MI] and major bleeding). A prospective, randomized, multicenter trial (ClinicalTrials.gov Identifier: NCT02049229), will be conducted in interventional centres in Finland (six centres), France (five centres) and Holland (two centres), including a total of 1800 patients.

  16. Everolimus-eluting bioresorbable stent vs. durable polymer everolimus-eluting metallic stent in patients with ST-segment elevation myocardial infarction

    DEFF Research Database (Denmark)

    Sabaté, Manel; Windecker, Stephan; Iñiguez, Andres

    2015-01-01

    AIMS: Patients with ST-segment elevation myocardial infarction (STEMI) feature thrombus-rich lesions with large necrotic core, which are usually associated with delayed arterial healing and impaired stent-related outcomes. The use of bioresorbable vascular scaffolds (Absorb) has the potential to ...

  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. Balloon Angioplasty for In-Stent Restenosis Resulting in Carotid Stent Fracture: Literature Review of Stent-in-Stent Technique as a Viable Therapeutic Option.

    Science.gov (United States)

    Naeem, Abdul-Haseeb; Al-Rumaihi, Ghaya; Namavarian, Amirpouyan; Sharma, Manas; Boulton, Melfort

    2017-05-01

    Carotid stent fractures are rare, and multiple etiologies have been proposed to explain their occurrence. We describe a patient with an internal carotid artery (ICA) stent who developed in-stent restenosis. We performed balloon angioplasty to address in-stent restenosis, but he developed a carotid stent fracture after the procedure. To our knowledge, balloon angioplasty has not been reported to cause stent fractures. A 72-year-old man underwent stent placement for symptomatic left ICA stenosis with residual stenosis of 55% after stent placement. He presented with transient ischemic attacks 2 months later, and work-up revealed in-stent restenosis of the left ICA. Given prior complete occlusion of right ICA and right vertebral artery and narrowing of left vertebral artery ostium, satisfactory balloon (5 × 40 mm) angioplasty was carried out. After balloon angioplasty, x-ray showed a new stent fracture, which was initially missed on immediate postoperative imaging. He presented 9 months later with symptoms of compromised cerebral perfusion. Work-up revealed the previously missed stent fracture causing blood flow changes. Peak systolic velocity in the left ICA was 383 cm/second. He underwent left ICA repeat stent placement via a stent-in-stent technique for symptomatic severe left ICA stenosis of 70% with 40% residual stenosis after new stent deployment. Balloon angioplasty to address in-stent restenosis can secondarily cause stent fractures. We provide evidence of successful management of stent fracture with recurrent in-stent stenosis by repeat stent placement via a stent-in-stent technique. Copyright © 2017 Elsevier Inc. All rights reserved.

  19. The REMEDEE-OCT Study: An Evaluation of the Bioengineered COMBO Dual-Therapy CD34 Antibody-Covered Sirolimus-Eluting Coronary Stent Compared With a Cobalt-Chromium Everolimus-Eluting Stent in Patients With Acute Coronary Syndromes: Insights From Optical Coherence Tomography Imaging Analysis

    NARCIS (Netherlands)

    Jaguszewski, Milosz; Aloysius, Romila; Wang, Wei; Bezerra, Hiram G.; Hill, Jonathan; de Winter, Robbert J.; Karjalainen, Pasi P.; Verheye, Stefan; Wijns, William; Lüscher, Thomas F.; Joner, Michael; Costa, Marco; Landmesser, Ulf

    2017-01-01

    The aim of the present study was to evaluate vascular healing of the bioengineered COMBO Dual Therapy Stent compared with a cobalt-chromium (CoCr) everolimus-eluting stent (EES) as assessed by optical coherence tomography in patients with acute coronary syndromes. CD34+ cells promote endothelial

  20. A randomized multicenter comparison of hybrid sirolimus-eluting stents with bioresorbable polymer versus everolimus-eluting stents with durable polymer in total coronary occlusion: rationale and design of the Primary Stenting of Occluded Native Coronary Arteries IV study

    Directory of Open Access Journals (Sweden)

    Teeuwen Koen

    2012-12-01

    Full Text Available Abstract Background Percutaneous recanalization of total coronary occlusion (TCO was historically hampered by high rates of restenosis and reocclusions. The PRISON II trial demonstrated a significant restenosis reduction in patients treated with sirolimus-eluting stents compared with bare metal stents for TCO. Similar reductions in restenosis were observed with the second-generation zotarolimus-eluting stent and everolimus-eluting stent. Despite favorable anti-restenotic efficacy, safety concerns evolved after identifying an increased rate of very late stent thrombosis (VLST with drug-eluting stents (DES for the treatment of TCO. Late malapposition caused by hypersensitivity reactions and chronic inflammation was suggested as a probable cause of these VLST. New DES with bioresorbable polymer coatings were developed to address these safety concerns. No randomized trials have evaluated the efficacy and safety of the new-generation DES with bioresorbable polymers in patients treated for TCO. Methods/Design The prospective, randomized, single-blinded, multicenter, non-inferiority PRISON IV trial was designed to evaluate the safety, efficacy, and angiographic outcome of hybrid sirolimus-eluting stents with bioresorbable polymers (Orsiro; Biotronik, Berlin, Germany compared with everolimus-eluting stents with durable polymers (Xience Prime/Xpedition; Abbott Vascular, Santa Clara, CA, USA in patients with successfully recanalized TCOs. In total, 330 patients have been randomly allocated to each treatment arm. Patients are eligible with estimated duration of TCO ≥4 weeks with evidence of ischemia in the supply area of the TCO. The primary endpoint is in-segment late luminal loss at 9-month follow-up angiography. Secondary angiographic endpoints include in-stent late luminal loss, minimal luminal diameter, percentage of diameter stenosis, in-stent and in-segment binary restenosis and reocclusions at 9-month follow-up. Additionally, optical coherence

  1. 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.

  2. Evolution of covered stents in the contemporary era: clinical application, materials and manufacturing strategies using nanotechnology.

    Science.gov (United States)

    Farhatnia, Yasmin; Tan, Aaron; Motiwala, Aamir; Cousins, Brian G; Seifalian, Alexander M

    2013-01-01

    Endovascular stents have revolutionised the field of interventional cardiology. Despite their excellent clinical outcome complications associated with percutaneous stent implantation following the procedure have remained a major drawback in their widespread use. To overcome such limitations, a number of novel endovascular stents have emerged including a covered stent wrapped in a thin membrane sleeve. As well as prevention of complications associated with stenting, covered stents owing to their physical barrier are used as the treatment option of choice for trauma devices during emergency situations and to treat a number of pathological disease states. The aim of this review is to provide the reader with an overall objective outlook in the use of covered stents as a treatment option in a number of vascular complications and addresses their design and materials used in the manufacturing process. In addition, new strategies are highlighted and future prospects with the emergence of novel smart alloys for 3D scaffolds and the use of nanotechnology in the development of nanocomposite materials. Copyright © 2013 Elsevier Inc. All rights reserved.

  3. Treatment of intracranial stenoses using the Neuroform stent system: initial experience in five cases

    Energy Technology Data Exchange (ETDEWEB)

    Haehnel, Stefan; Hartmann, Marius [University of Heidelberg Medical Center, Division of Neuroradiology, Department of Neurology, Heidelberg (Germany); Ringleb, Peter [University of Heidelberg Medical Center, Division of Neurology, Department of Neurology, Heidelberg (Germany)

    2006-07-15

    We assessed the technical feasibility of balloon-assisted angioplasty with consecutive stenting using a flexible, self-expanding neurovascular stent for the treatment of intracranial arteriosclerotic vascular stenoses. Five consecutive patients with symptomatic drug-resistant stenoses of the intracranial internal carotid artery (ICA) or the main stem of the middle cerebral artery (MCA) were treated by balloon-assisted angioplasty with consecutive stenting using the Neuroform stent system. Balloon dilatation of the stenoses and consecutive stent placement with complete coverage of the stenoses was feasible in all patients. One patient suffered acute thrombosis distally to the stented vessel segment which was successfully treated by fibrinolysis, and one patient suffered acute subarachnoid and parenchymal hemorrhage probably due to vessel perforation. In the other three patients, no complications occurred during or immediately after angioplasty. All patients were free of further ischemic events up to the 6-month follow-up. Our findings demonstrate that the Neuroform stent system can used successfully for the treatment of intracranial stenoses of the ICA and the main stem of the MCA. Although immediate angiographic results are promising, long-term angiographic and clinical follow-up is essential to demonstrate long-term outcome. (orig.)

  4. Use of Micropatterned Thin Film Nitinol in Carotid Stents to Augment Embolic Protection

    Directory of Open Access Journals (Sweden)

    Mahdis Shayan

    2016-12-01

    Full Text Available Stenting is an alternative to endarterectomy for the treatment of carotid artery stenosis. However, stenting is associated with a higher risk of procedural stroke secondary to distal thromboembolism. Hybrid stents with a micromesh layer have been proposed to address this complication. We developed a micropatterned thin film nitinol (M-TFN covered stent designed to prevent thromboembolism during carotid intervention. This innovation may obviate the need or work synergistically with embolic protection devices. The proposed double layered stent is low-profile, thromboresistant, and covered with a M-TFN that can be fabricated with fenestrations of varying geometries and sizes. The M-TFN was created in multiple geometries, dimensions, and porosities by sputter deposition. The efficiency of various M-TFN to capture embolic particles was evaluated in different atherosclerotic carotid stenotic conditions through in vitro tests. The covered stent prevented emboli dislodgement in the range of 70%–96% during 30 min duration tests. In vitro vascular cell growth study results showed that endothelial cell elongation, alignment and growth behaviour silhouettes significantly enhance, specifically on the diamond-shape M-TFN, with the dimensions of 145 µm × 20 µm and a porosity of 32%. Future studies will require in vivo testing. Our results demonstrate that M-TFN has a promising potential for carotid artery stenting.

  5. Cobalt chromium-based biodegradable polymer sirolimus-eluting stent: rationale, evidence and clinical experience.

    Science.gov (United States)

    Pan, D R; Zhu, H; Hu, Z Y; Pang, S; Wu, W; Tian, N L; Xu, B; Iqbal, J; Zhang, Y J

    2015-10-01

    Metallic drug-eluting stents (DES) are the first choice for percutaneous coronary interventional treatment of coronary artery disease at present. Although they have overcome some disadvantages and limitations of plain balloon angioplasty and bare-metal stents, chronic local inflammatory reactions related to permanent polymer existence and poor vascular healing after first generation DES implantation may translate into the increased risk of late and very late stent thrombosis. There have been technological developments in stent design, materials and coatings, including more conformable platform designs, biocompatible or biodegradable polymers and improved kinetics of drug release. The newer generation DES have proven superior to previous DES technology in terms of both safety and efficacy. Accumulating evidence has suggested that DES with cobalt chromium stent platform, modified biodegradable polymer coatings, and rapamycin derivative drugs are associated with improved clinical outcomes. Currently, several new cobalt chromium biodegradable polymer sirolimus-eluting stents have been introduced to clinical practice. This review will describe basic concept and rationale behind the newer cobalt chromium biodegradable polymer sirolimus-eluting stents, systematically present the new clinical experiences with several representative devices.

  6. Endoscopic ultrasonography-guided placement of a transhepatic portal vein stent in a live porcine model.

    Science.gov (United States)

    Park, Tae Young; Seo, Dong Wan; Kang, Hyeon-Ji; Cho, Min Keun; Song, Tae Jun; Park, Do Hyun; Lee, Sang Soo; Lee, Sung Koo; Kim, Myung-Hwan

    2016-01-01

    Percutaneous portal vein (PV) stent placement is used to manage PV occlusion or stenosis caused by malignancy. The use of endoscopic ultrasonography (EUS) has expanded to include vascular interventions. The aim of this study was to examine the technical feasibility and safety of EUS-guided transhepatic PV stent placement in a live porcine model. EUS-guided transhepatic PV stent placement was performed in six male miniature pigs under general anesthesia using forward-viewing echoendoscope. Under EUS guidance, the left intrahepatic PV was punctured with a 19-gauge fine-needle aspiration (FNA) needle and a 0.025 inch guidewire inserted through the needle and into the main PV. The FNA needle was then withdrawn and a needle-knife inserted to dilate the tract. Under EUS and fluoroscopic guidance, a noncovered metal stent was inserted over the guidewire and released into the main PV. A PV stent was placed successfully in all six pigs with no technical problems or complications. The patency of the stent in the main PV was confirmed using color Doppler EUS and transhepatic portal venography. Necropsy of the first three animals revealed no evidence of bleeding and damage to intra-abdominal organs or vessels. No complications occurred in the remaining three animals during the 8 weeks observation period. EUS-guided transhepatic PV stent placement can be both technically feasible and safe in a live animal model.

  7. Endovascular stents for dialysis access: under what circumstances do the data support their use?

    Science.gov (United States)

    Yevzlin, Alexander S; Maya, Ivan D; Asif, Arif

    2009-09-01

    Despite strict K/DOQI clinical practice guidelines regarding the deployment of stents in the hemodialysis vascular circuit, their use has increased exponentially over the last 10 years in both arteriovenous fistulas and grafts. The literature is very scant regarding outcomes, with most studies suffering from design flaws. Some authors have advocated the use of stents for specific clinical scenarios, such as patients with thrombosed arteriovenous grafts or ones with a severe stenosis at the venous anastomosis. Others have advocated a more liberal strategy to deploy stents at a variety of sites if the stenotic lesion remains greater than 30% after angioplasty. Although not approved for the treatment of pseudoaneurysms in the AV grafts, stent use in this setting is emerging to be an important strategy. The use of stents as a treatment for rupture of a vessel while performing a percutaneous angioplasty is well described and performed routinely. It is important to recognize the clinical scenarios when stent placement may present a distinct disadvantage (eg, loss of a potential secondary fistula creation in the same extremity). Finally, well-designed studies need to address all these issues to clarify indications and to provide stronger scientific guidelines for stent use.

  8. Endovascular treatment of wide-neck anterior communicating artery aneurysms using the LVIS Junior stent.

    Science.gov (United States)

    Feng, Zhengzhe; Zhang, Lei; Li, Qiang; Zhao, Rui; Xu, Yi; Hong, Bo; Zhao, Wenyuan; Liu, Jianmin; Huang, Qinghai

    2015-08-01

    We performed this retrospective study to assess the clinical safety and efficacy of the low-profile visualized intraluminal support junior (LVIS Jr.; MicroVention, Aliso Viejo, CA, USA) stent placement in anterior communicating artery (ACA) aneurysms. ACA aneurysms are some of the most common intracranial aneurysms. Stent placement is particularly difficult due to the complexity of the vascular anatomy and the small vessels of the ACA complex. From November 2013 and June 2014, LVIS Jr. stent-assisted coiling was performed in 11 patients with 12 wide-neck ACA aneurysms. Patient demographics, morphologic features of the aneurysm, clinical results and follow-up results are presented. Successful deployment of the LVIS Jr. stent in the targeted artery was achieved in all patients. Complete occlusion was achieved in seven patients, neck remnant in three, and partial occlusion in two. The angiographic follow-up of nine patients (mean 4.4 months) showed that all aneurysms remained stable or improved. There was no in-stent stenosis, recurrence or retreatment. The modified Rankin scale score at discharge was 0 in eight patients and 1 in three patients. The LVIS Jr. stent provided excellent trackability and deliverability and is safe and effective for the treatment of wide-necked ACA aneurysms. Further follow-up is needed to assess the long-term efficacy of LVIS Jr. stent placement in ACA. Copyright © 2015 Elsevier Ltd. All rights reserved.

  9. 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

  10. Expansion Characteristics of Stents Used in Congenital Heart Disease: Serial Dilation Offers Improved Expansion Potential Compared to Direct Dilation: Results from a Pediatric Interventional Cardiology Early Career Society (PICES) Investigation.

    Science.gov (United States)

    Danon, Saar; Gray, Robert G; Crystal, Matthew A; Morgan, Gareth; Gruenstein, Daniel H; Goldstein, Bryan H; Gordon, Brent M

    2016-12-01

    Intravascular stents are now routinely used to treat young patients with vascular stenoses. Future stent redilations are often necessary to account for somatic growth. The purpose of this study was to compile a database of characteristics for stents commonly used in the treatment of congenital heart disease patients, and compare serial dilation to direct dilation to the maximal diameter. A standardized bench testing protocol was established and utilized in the assessment of all stents. Ultra high pressure balloons were used to serially dilate each stent by set increments until the stent reached at least 24 mm in diameter, developed a napkin-ring configuration, or fractured. Length and diameter of each stent were measured at baseline and following each stage of dilation. Maximal stent diameters, foreshortening properties, and ability to fracture were reported. Stents were then tested for direct dilation from the primary diameter to the maximal diameter, and the same data was obtained. A total of 127 stents were bench-tested, 80 of which were serially dilated and 47 directly dilated. Most premounted stents could be serially dilated to approximately twice their stated nominal diameter. All tested unmounted stents could be serially dilated to ≥20 mm. Foreshortening occurred at larger diameters, but varied significantly among different stent types. Serial dilation offered more consistent results with significantly less foreshortening and more symmetric expansion when compared with direct dilation. Most premounted stents could be fractured when serially dilated. All tested vascular stents can be dilated beyond their nominal implantation diameter. Serial dilation offers a much more reliable response with uniform expansion, less foreshortening, greater maximal diameter, and improved intentional fracture potential, as compared to direct dilation from the nominal to maximal diameter. In vivo studies are necessary to corroborate these findings in the congenital heart

  11. Preliminary Report of Carotid Artery Stenting Using a Tapered Stent

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Chang Woo; Kim, Dong Hyun; Hong, Seung; Jeong; Kim, Young Suk; Byun, Joo Nam; Oh, Jae Hee [Dept. of Radiology, Chosun University College of Medicine, Gwangju (Korea, Republic of); Ahn, Seong Hwan [Dept. of Neurology, Chosun University College of Medicine, Gwangju (Korea, Republic of)

    2011-10-15

    To analyze the results of carotid artery stenting using a tapered stent and to evaluate the effectiveness of the tapered stent compared to previously reported studies using non-tapered stents. From October 2008 to August 2010, elective carotid artery stenting using a tapered stent was attempted in 39 lesions from 36 consecutive patients. Post-procedural complications were evaluated by neurologic symptoms and magnetic resonance imaging. Restenosis or occlusion was evaluated by carotid Doppler ultrasound and computerized tomography with angiography. Newly developed neurologic symptoms were evaluated clinically. The self-expandable tapered stent was placed across the carotid artery stenosis. A total stroke was noted in 3 patients, while a major stroke was noted in 1 patient. On diffusion weighted imaging, new lesions were observed in 15 patients, but 13 patients were clinically silent. Follow-up imaging studies were performed in the 13 clinically silent lesions, and no evidence of restenosis or occlusion was found any of the 13 lesions. During clinical follow-up in 34 lesions from 31 patients, there were newly developed neurological symptoms in only 1 patient.

  12. Delivery of large biopharmaceuticals from cardiovascular stents: a review.

    Science.gov (United States)

    Takahashi, Hironobu; Letourneur, Didier; Grainger, David W

    2007-11-01

    This review focuses on new and emerging large-molecule bioactive agents delivered from stent surfaces in drug-eluting stents (DESs) to inhibit vascular restenosis in the context of interventional cardiology. New therapeutic agents representing proteins, nucleic acids (small interfering RNAs and large DNA plasmids), viral delivery vectors, and even engineered cell therapies require specific delivery designs distinct from traditional smaller-molecule approaches on DESs. While small molecules are currently the clinical standard for coronary stenting, extension of the DESs to other lesion types, peripheral vasculature, and nonvasculature therapies will seek to deliver an increasingly sophisticated armada of drug types. This review describes many of the larger-molecule and biopharmaceutical approaches reported recently for stent-based delivery with the challenges associated with formulating and delivering these drug classes compared to the current small-molecule drugs. It also includes perspectives on possible future applications that may improve safety and efficacy and facilitate diversification of the DESs to other clinical applications.

  13. Carotid artery stenting; Karotisangioplastie

    Energy Technology Data Exchange (ETDEWEB)

    Fiehler, Jens [Universitaetsklinikum Eppendorf, Hamburg (Germany). Klinik und Poliklinik fuer Neuroradiologische Diagnostik und Intervention, Diagnostikzentrum

    2009-09-15

    An ipsilateral stenosis of the internal carotid artery is found in 10 - 15 % of all ischemic strokes and indicates an increased risk of a second stroke. Carotid artery stenting (CAS) is a therapy that is established for many years. CAS reveals complication rates and long-term efficacy comparable to carotid endarterectomy (TEA). Especially younger patients seem to benefit from CAS. Abilities and experiences of the therapist and the choice of the techniques used are critical for patient safety. The efficacy of CAS for treatment of asymptomatic carotid stenosis is probable but still unproven in prospective-randomized trial. (orig.)

  14. Successful endovascular treatment of a hemodialysis graft pseudoaneurysm by covered stent and direct percutaneous thrombin injection.

    LENUS (Irish Health Repository)

    Keeling, Aoife N

    2011-07-25

    Vascular access for hemodialysis remains a challenge for nephrologists, vascular surgeons, and interventional radiologists alike. Arteriovenous fistula and synthetic grafts remain the access of choice for long-term hemodialysis; however, they are subject to complications from infection and repeated needle cannulation. Pseudoaneurysms are an increasingly recognized adverse event. At present, there are many minimally invasive methods to repair these wall defects. We present a graft pseudoaneurysm, which required a combination of endovascular stent graft placement and percutaneous thrombin injection for successful occlusion.

  15. Bilateral spontaneous internal carotid artery dissection managed with endovascular stenting – A case report

    Directory of Open Access Journals (Sweden)

    Manoj Kumar Agarwala

    2016-09-01

    We describe a patient with ischemic stroke from spontaneous bilateral ICAD with completely occluded left ICA. Having failed medical therapy with antiplatelets and anticoagulants due to extensive loss of carotid vascular supply, he was managed successfully with endovascular stenting with good neurological recovery.

  16. DJ stent - boon or curse?

    Directory of Open Access Journals (Sweden)

    AS Agrawal

    2014-04-01

    Full Text Available DJ stent is considered as a boon by the urologist but without proper knowledge it turns to be curse for the patient. We report a case of a 34 year old man who developed vesical calculus secondary to DJ stent in a short span of 6-8 months. He underwent cystolithotomy for removal of the vesical calculus along with the DJ stent. Journal of College of Medical Sciences-Nepal, 2013, Vol-9, No-3, 55-59 DOI: http://dx.doi.org/10.3126/jcmsn.v9i3.10224  

  17. Biodegradable stents in gastrointestinal endoscopy.

    Science.gov (United States)

    Lorenzo-Zúñiga, Vicente; Moreno-de-Vega, Vicente; Marín, Ingrid; Boix, Jaume

    2014-03-07

    Biodegradable stents (BDSs) are an attractive option to avoid ongoing dilation or surgery in patients with benign stenoses of the small and large intestines. The experience with the currently the only BDS for endoscopic placement, made of Poly-dioxanone, have shown promising results. However some aspects should be improved as are the fact that BDSs lose their radial force over time due to the degradable material, and that can cause stent-induced mucosal or parenchymal injury. This complication rate and modest clinical efficacy has to be carefully considered in individual patients prior to placement of BDSs. Otherwise, the price of these stents therefore it is nowadays an important limitation.

  18. Asymmetric Divisions in Oogenesis.

    Science.gov (United States)

    Bilinski, Szczepan M; Kubiak, Jacek Z; Kloc, Malgorzata

    In the majority of animals, the oocyte/egg is structurally, molecularly, and functionally asymmetric. Such asymmetry is a prerequisite for a flawless fertilization and faithful segregation of maternal determinants during subsequent embryonic development. The oocyte asymmetry develops during oogenesis and must be maintained during consecutive and obligatorily asymmetric oogonial divisions, which depending on the species lead to the formation of either oocyte alone or oocyte and nurse cell complex. In the following chapter, we summarize current knowledge on the asymmetric oogonial divisions in invertebrate (insects) and vertebrate (Xenopus) species.

  19. 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.

  20. Evaluating stent optimisation technique (StentBoost®) in a dedicated bifurcation stent (the Tryton™).

    Science.gov (United States)

    Fysal, Zamil; Hyde, Thomas; Barnes, Edward; McCrea, William; Ramcharitar, Steve

    2014-03-01

    To evaluate the use of StentBoost® in the Tryton™ dedicated SideBranch Stent. 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. 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. Copyright © 2014 Elsevier Inc. All rights reserved.

  1. The engineering of endovascular stent technology: a review.

    Science.gov (United States)

    Whittaker, David R; Fillinger, Mark F

    2006-01-01

    The evolution of minimally invasive endovascular technology has initiated a significant paradigm shift in the treatment of vascular disease. A fundamental understanding of the science and engineering behind the technology of endovascular stents is a key to their appropriate implementation in practice. Furthermore, the rapid influx of new devices into the field requires practitioners to make their decisions on a foundation of the relative strengths and weaknesses of the various products. Although the principles of their use are not complex, the device design can have a profound effect on the device's functionality. Shape, thickness, coating, material selection, and imaging are just a few of the factors to consider in stent design. Subtle differences may have profound results. This review is designed to provide the reader with an overview of fundamental concepts that will aide the assessment of new technology.

  2. VASCULAR SURGERY

    African Journals Online (AJOL)

    2016-06-02

    Jun 2, 2016 ... Aortic arch injuries. (2) were repaired operatively with cardiopulmonary bypass, descending aortic injuries (2) were treated by stent graft, and common carotid (1) and subclavian artery injuries (2) were treated by open repair at the quaternary centre. Of the 20 venous injuries that were managed operatively,.

  3. Stent Placement for Carotid Web.

    Science.gov (United States)

    Martinez-Perez, Rafael; Lownie, Stephen P; Pandey, Sachin K; Boulton, Mel R

    2017-02-01

    The carotid web is an intraluminal shelf-like projection arising from the posterior wall of the carotid bifurcation and an uncommon etiology of ischemic strokes. We describe the feasibility of endovascular stent placement to treat this condition. A 47-year-old woman presented with a sudden occlusion of the right middle cerebral artery. Computed tomography angiography and digital subtraction angiography showed a carotid web in the ipsilateral carotid bifurcation. Treatment included mechanical thrombectomy for the middle cerebral artery occlusion and carotid stent placement to prevent further ischemic episodes from the carotid web. At the 6-month follow-up, good apposition of the stent against the artery wall was noted, and the patient was free of neurologic symptoms. Carotid artery stent placement is a feasible option in the management of carotid webs. Copyright © 2016 Elsevier Inc. All rights reserved.

  4. How does spa treatment affect cardiovascular function and vascular endothelium in patients with generalized osteoarthritis? A pilot study through plasma asymmetric di-methyl arginine (ADMA) and L-arginine/ADMA ratio

    Science.gov (United States)

    Karaarslan, Fatih; Ozkuk, Kagan; Seringec Karabulut, Serap; Bekpinar, Seldag; Karagulle, Mufit Zeki; Erdogan, Nergis

    2017-12-01

    The study aims to investigate the effect of spa treatment on vascular endothelium and clinical symptoms of generalized osteoarthritis. Forty generalized osteoarthritis (GOA) patients referred to a government spa hospital, and 40 GOA patients followed on university hospital locomotor system disease ambulatory clinics were included as study and control groups, respectively. Study group received spa treatment including thermal water baths, physical therapy modalities, and exercises. Control group was followed with home exercises for 15 days. Plasma ADMA, L-arginine, L-arginine/ADMA ratio, routine blood analyses, 6-min walking test, including fingertip O2 saturation, systolic/diastolic blood pressure, and pulse rate, were measured at the beginning and at the end of treatment. Groups were evaluated with VAS pain, patient, and physician global assessment; HAQ; and WOMAC at the beginning, at the end, and after 1 month of treatment. In study group, L-arginine and L-arginine/ADMA ratio showed statistically significant increase after treatment. Plasma ADMA levels did not change. There is no significant difference in intergroup comparison. Study group displayed statistically significant improvements in all clinical parameters. The study showed that spa treatment does not cause any harm to the vascular endothelium through ADMA. Significant increase in plasma L-arginine and L-arginine/ADMA ratio suggests that balneotherapy may play a preventive role on cardiovascular diseases. Balneotherapy provides meaningful improvements on clinical parameters of GOA.

  5. How does spa treatment affect cardiovascular function and vascular endothelium in patients with generalized osteoarthritis? A pilot study through plasma asymmetric di-methyl arginine (ADMA) and L-arginine/ADMA ratio.

    Science.gov (United States)

    Karaarslan, Fatih; Ozkuk, Kagan; Seringec Karabulut, Serap; Bekpinar, Seldag; Karagulle, Mufit Zeki; Erdogan, Nergis

    2017-12-07

    The study aims to investigate the effect of spa treatment on vascular endothelium and clinical symptoms of generalized osteoarthritis. Forty generalized osteoarthritis (GOA) patients referred to a government spa hospital, and 40 GOA patients followed on university hospital locomotor system disease ambulatory clinics were included as study and control groups, respectively. Study group received spa treatment including thermal water baths, physical therapy modalities, and exercises. Control group was followed with home exercises for 15 days. Plasma ADMA, L-arginine, L-arginine/ADMA ratio, routine blood analyses, 6-min walking test, including fingertip O2 saturation, systolic/diastolic blood pressure, and pulse rate, were measured at the beginning and at the end of treatment. Groups were evaluated with VAS pain, patient, and physician global assessment; HAQ; and WOMAC at the beginning, at the end, and after 1 month of treatment. In study group, L-arginine and L-arginine/ADMA ratio showed statistically significant increase after treatment. Plasma ADMA levels did not change. There is no significant difference in intergroup comparison. Study group displayed statistically significant improvements in all clinical parameters. The study showed that spa treatment does not cause any harm to the vascular endothelium through ADMA. Significant increase in plasma L-arginine and L-arginine/ADMA ratio suggests that balneotherapy may play a preventive role on cardiovascular diseases. Balneotherapy provides meaningful improvements on clinical parameters of GOA.

  6. Biodegradable stents in gastrointestinal endoscopy

    OpenAIRE

    Lorenzo-Zúñiga, Vicente; Moreno-de-Vega, Vicente; Marín, Ingrid; Boix, Jaume

    2014-01-01

    Biodegradable stents (BDSs) are an attractive option to avoid ongoing dilation or surgery in patients with benign stenoses of the small and large intestines. The experience with the currently the only BDS for endoscopic placement, made of Poly-dioxanone, have shown promising results. However some aspects should be improved as are the fact that BDSs lose their radial force over time due to the degradable material, and that can cause stent-induced mucosal or parenchymal injury. This complicatio...

  7. Vascular Cures

    Science.gov (United States)

    ... is the first national program to bring the power of the patient to vascular research and care. ... Our recent national Vascular Research Summit brought together leaders from 31 institutions to generate collaborative projects for ...

  8. Flow-induced corrosion behavior of absorbable magnesium-based stents.

    Science.gov (United States)

    Wang, Juan; Giridharan, Venkataraman; Shanov, Vesselin; Xu, Zhigang; Collins, Boyce; White, Leon; Jang, Yongseok; Sankar, Jagannathan; Huang, Nan; Yun, Yeoheung

    2014-12-01

    The aim of this work was to study corrosion behavior of magnesium (Mg) alloys (MgZnCa plates and AZ31 stents) under varied fluid flow conditions representative of the vascular environment. Experiments revealed that fluid hydrodynamics, fluid flow velocity and shear stress play essential roles in the corrosion behavior of absorbable magnesium-based stent devices. Flow-induced shear stress (FISS) accelerates the overall corrosion (including localized, uniform, pitting and erosion corrosions) due to the increased mass transfer and mechanical force. FISS increased the average uniform corrosion rate, the localized corrosion coverage ratios and depths and the removal rate of corrosion products inside the corrosion pits. For MgZnCa plates, an increase of FISS results in an increased pitting factor but saturates at an FISS of ∼0.15Pa. For AZ31 stents, the volume loss ratio (31%) at 0.056Pa was nearly twice that (17%) at 0Pa before and after corrosion. Flow direction has a significant impact on corrosion behavior as more severe pitting and erosion corrosion was observed on the back ends of the MgZnCa plates, and the corrosion product layer facing the flow direction peeled off from the AZ31 stent struts. This study demonstrates that flow-induced corrosion needs be understood so that Mg-based stents in vascular environments can be effectively designed. Copyright © 2014 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  9. In vivo response of AZ31 alloy as biliary stents: a 6 months evaluation in rabbits

    Science.gov (United States)

    Liu, Yang; Zheng, Shengmin; Li, Nan; Guo, Huahu; Zheng, Yufeng; Peng, Jirun

    2017-01-01

    Mg-based metallic materials have been making continuing progress as vascular stents. However, the research of Mg-based materials as non-vascular stents is still at its primary stage. AZ31 stents hereby were implanted into the common bile duct of rabbits for 6 months. The results revealed an existence of 93.82 ± 1.36% and 30.89 ± 2.46% of the original volume after 1 and 3 month, respectively. Whole blood tests indicated an inflammation decreasing to normal level after 3 month implantation. A benign host response was observed via H&E staining. Nonuniform corrosion at the two ends of the stents was observed and considered the results of flow or local inflammation. Moreover, the application of Mg-based materials for different stenting treatment were reviewed and compared. Esophagus was hypothesized most destructive, whilst blood vessel and bile duct considered similar and less destructive. Trachea and nasal cavity were thought to be mildest.

  10. Multi-objective optimization of coronary stent using Kriging surrogate model.

    Science.gov (United States)

    Li, Hongxia; Gu, Junfeng; Wang, Minjie; Zhao, Danyang; Li, Zheng; Qiao, Aike; Zhu, Bao

    2016-12-28

    In stent design optimization, the functional relationship between design parameters and design goals is nonlinear, complex, and implicit and the multi-objective design of stents involves a number of potentially conflicting performance criteria. Therefore it is hard and time-consuming to find the optimal design of stent either by experiment or clinic test. Fortunately, computational methods have been developed to the point whereby optimization and simulation tools can be used to systematically design devices in a realistic time-scale. The aim of the present study is to propose an adaptive optimization method of stent design to improve its expansion performance. Multi-objective optimization method based on Kriging surrogate model was proposed to decrease the dogboning effect and the radial elastic recoil of stents to improve stent expansion properties and thus reduce the risk of vascular in-stent restenosis injury. Integrating design of experiment methods and Kriging surrogate model were employed to construct the relationship between measures of stent dilation performance and geometric design parameters. Expected improvement, an infilling sampling criterion, was employed to balance local and global search with the aim of finding the global optimal design. A typical diamond-shaped coronary stent-balloon system was taken as an example to test the effectiveness of the optimization method. Finite element method was used to analyze the stent expansion of each design. 27 iterations were needed to obtain the optimal solution. The absolute values of the dogboning ratio at 32 and 42 ms were reduced by 94.21 and 89.43%, respectively. The dogboning effect was almost eliminated after optimization. The average of elastic recoil was reduced by 15.17%. This article presents FEM based multi-objective optimization method combining with the Kriging surrogate model to decrease both the dogboning effect and radial elastic recoil of stents. The numerical results prove that the proposed

  11. Ab interno stenting procedures.

    Science.gov (United States)

    Radcliffe, Nathan M; Lynch, Mary G; Brown, Reay H

    2014-08-01

    Trabecular bypass was first used as a surgical treatment for glaucoma more than 100 years ago and aims to circumvent the trabecular meshwork, thought to be the main site of aqueous humor outflow resistance. The emerging field of microinvasive glaucoma surgery has brought a new ab interno trabecular microbypass stent through the U.S. Food and Drug Administration-approval process, and data from long-term randomized prospective trials have shown the safety and intraocular pressure-lowering value of trabecular microbypass. This review discusses the historical evolution of trabecular microbypass and describes new and forthcoming surgical options along with available clinical safety and efficacy data. Proprietary or commercial disclosures are listed after the references. Copyright © 2014 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

  12. Endoscopic therapy for esophageal perforation or anastomotic leak with a self-expandable metallic stent.

    Science.gov (United States)

    Leers, Jessica M; Vivaldi, Carlo; Schäfer, Hartmut; Bludau, Marc; Brabender, Jan; Lurje, Georg; Herbold, Till; Hölscher, Arnulf H; Metzger, Ralf

    2009-10-01

    Leaks of the esophagus are associated with a high mortality rate and need to be treated as soon as possible. Therapeutic options are surgical repair or resection or conservative management with cessation of oral intake and antibiotic therapy. We evaluated an alternative approach that uses self-expandable metallic stents (SEMS). Between 2002 and 2007, 31 consecutive patients with iatrogenic esophageal perforation (n = 9), intrathoracic anastomotic leak after esophagectomy (n = 16), spontaneous tumor perforation (n = 5), and esophageal ischemia (n = 1) were treated at our institution. All were treated with endoscopic placement of a covered SEMS. Stent removal was performed 4 to 6 weeks after implantation. To exclude continuous esophageal leak after SEMS placement, radiologic examination was performed after stent implantation and removal. SEMS placement was successful in all patients and a postinterventional esophagogram demonstrated full coverage of the leak in 29 patients (92%). In two patients, complete sealing could not be achieved and they were referred to surgical repair. Stent migration was seen in only one patient (3%). After removal, a second stent with larger diameter was placed and no further complication occurred. Two patients died: one due to myocardial infarction and one due to progressive ischemia of the esophagus and small bowl as a consequence of vascular occlusion. Stent removal was performed within 6 weeks, and all patients had radiologic and endoscopic evidence of esophageal healing. Implantation of covered SEMS in patients with esophageal leak or perforation is a safe and feasible alternative to operative treatment and can lower the interventional morbidity rate.

  13. 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.

  14. 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

    the randomised BASKET-PROVE trial (sirolimus-eluting stent vs. everolimus-eluting stent vs. bare metal stent in large-vessel stenting). The primary endpoint was the combined two-year rate of cardiovascular death or non-fatal myocardial infarction (MI). Secondary endpoints were each component of the primary...

  15. Randomized comparison of biodegradable polymer sirolimus-eluting stents versus durable polymer everolimus-eluting stents for percutaneous coronary revascularization: rationale and design of the BIOSCIENCE trial.

    Science.gov (United States)

    Pilgrim, Thomas; Roffi, Marco; Tüller, David; Muller, Olivier; Vuilliomenet, André; Cook, Stéphane; Weilenmann, Daniel; Kaiser, Christoph; Jamshidi, Peiman; Heg, Dik; Jüni, Peter; Windecker, Stephan

    2014-09-01

    Biodegradable polymers for release of antiproliferative drugs from metallic drug-eluting stents aim to improve long-term vascular healing and efficacy. We designed a large scale clinical trial to compare a novel thin strut, cobalt-chromium drug-eluting stent with silicon carbide-coating releasing sirolimus from a biodegradable polymer (O-SES, Orsiro; Biotronik, Bülach, Switzerland) with the durable polymer-based Xience Prime/Xpedition everolimus-eluting stent (EES) (Xience Prime/Xpedition stent, Abbott Vascular, IL) in an all-comers patient population. The multicenter BIOSCIENCE trial (NCT01443104) randomly assigned 2,119 patients to treatment with biodegradable polymer sirolimus-eluting stents (SES) or durable polymer EES at 9 sites in Switzerland. Patients with chronic stable coronary artery disease or acute coronary syndromes, including non-ST-elevation and ST-elevation myocardial infarction, were eligible for the trial if they had at least 1 lesion with a diameter stenosis >50% appropriate for coronary stent implantation. The primary end point target lesion failure (TLF) is a composite of cardiac death, target vessel myocardial infarction, and clinically driven target lesion revascularization within 12 months. Assuming a TLF rate of 8% at 12 months in both treatment arms and accepting 3.5% as a margin for noninferiority, inclusion of 2,060 patients would provide more than 80% power to detect noninferiority of the biodegradable polymer SES compared with the durable polymer EES at a 1-sided type I error of 0.05. Clinical follow-up will be continued through 5 years. The BIOSCIENCE trial will determine whether the biodegradable polymer SES is noninferior to the durable polymer EES with respect to TLF. Copyright © 2014 Mosby, Inc. All rights reserved.

  16. Angioplasty and stent placement - carotid artery

    Science.gov (United States)

    ... and stenting; CAS; Angioplasty - carotid artery; Carotid artery stenosis - angioplasty; ... Stenting versus endarterectomy for treatment of carotid-arery stenosis. N Engl J Med . 2010;363(1):11- ...

  17. Haemodynamic impact of stent implantation for lateral tunnel Fontan stenosis: a patient-specific computational assessment.

    Science.gov (United States)

    Tang, Elaine; McElhinney, Doff B; Restrepo, Maria; Valente, Anne M; Yoganathan, Ajit P

    2016-01-01

    The physiological importance of the lateral tunnel stenosis in the Fontan pathway for children with single ventricle physiology can be difficult to determine. The impact of the stenosis and stent implantation on total cavopulmonary connection resistance has not been characterized, and there are no clear guidelines for intervention. Methods and results A computational framework for haemodynamic assessment of stent implantation in patients with lateral tunnel stenosis was developed. Cardiac magnetic resonances images were reconstructed to obtain total cavopulmonary connection anatomies before stent implantation. Stents with 2-mm diameter increments were virtually implanted in each patient to understand the impact of stent diameter. Numerical simulations were performed in all geometries with patient-specific flow rates. Exercise conditions were simulated by doubling and tripling the lateral tunnel flow rate. The resulting total cavopulmonary connection vascular resistances were computed. A total of six patients (age: 14.4 ± 3.1 years) with lateral tunnel stenosis were included for preliminary analysis. The mean baseline resistance was 1.54 ± 1.08 WU · m(2) and dependent on the stenosis diameter. It was further exacerbated during exercise. It was observed that utilising a stent with a larger diameter lowered the resistance, but the resistance reduction diminished at larger diameters. Using a computational framework to assess the severity of lateral tunnel stenosis and the haemodynamic impact of stent implantation, it was observed that stenosis in the lateral tunnel pathway was associated with higher total cavopulmonary connection resistance than unobstructed pathways, which was exacerbated during exercise. Stent implantation could reduce the resistance, but the improvement was specific to the minimum diameter.

  18. Very Late Pathological Responses to Cobalt-Chromium Everolimus-Eluting, Stainless Steel Sirolimus-Eluting, and Cobalt-Chromium Bare Metal Stents in Humans.

    Science.gov (United States)

    Mori, Hiroyoshi; Atmakuri, Dheeraj R; Torii, Sho; Braumann, Ryan; Smith, Samantha; Jinnouchi, Hiroyuki; Gupta, Anuj; Harari, Emanuel; Shkullaku, Melsi; Kutys, Robert; Fowler, David; Romero, Maria; Virmani, Renu; Finn, Aloke V

    2017-11-17

    The "very late" clinical outcomes for durable polymer drug-eluting stents and bare metal stents (BMSs) have been shown to be dissimilar in clinical studies. Conceptually, the long-term vascular compatibility of BMSs is still regarded to be superior to drug-eluting stents; however, no pathologic study to date has specifically addressed this issue. We evaluated the very late (≥1 year) pathologic responses to durable polymer drug-eluting stents (cobalt-chromium [CoCr] everolimus-eluting stents [EESs] and stainless steel sirolimus-eluting stents [SS-SESs]) versus BMSs (CoCr-BMSs). From the CVPath stent registry, we studied a total of 119 lesions (40 CoCr-EESs, 44 SS-SESs, 35 CoCr-BMSs) from 92 autopsy cases with a duration ranging from 1 to 5 years. Sections of stented coronary segments were pathologically analyzed. Inflammation score and the percentage of struts with giant cells were lowest in CoCr-EESs (median inflammation score: 0.6; median percentage of struts with giant cells: 3.8%) followed by CoCr-BMSs (median inflammation score: 1.3 [Pstents and may have implications for future stent design. © 2017 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley.

  19. Paclitaxel and sirolimus eluting stents versus bare metal stents: long-term risk of stent thrombosis and other outcomes. From the Western Denmark Heart Registry

    DEFF Research Database (Denmark)

    Jensen, Lisette Okkels; Tilsted, Hans Henrik; Thayssen, Per

    2010-01-01

    AIMS: Stent thrombosis is a serious complication of percutaneous coronary intervention (PCI). We examined the incidence of stent thrombosis and other outcomes in patients treated with PCI and paclitaxeleluting stents (PES), sirolimus-eluting stents (SES) or bare-metal stents (BMS). METHODS AND RE...

  20. Neoatherosclerosis development following bioresorbable vascular scaffold implantation in diabetic and non-diabetic swine

    NARCIS (Netherlands)

    N.S. van Ditzhuijzen (Nienke); M. Kurata (Mie); M.M. van den Heuvel (Mieke); O. Sorop (Oana); R.W.B. van Duin (R. W B); I. Krabbendam-Peters (I.); J.M.R. Ligthart (Jürgen); K.Th. Witberg (Karen); M. Murawska (Magdalena); B.E. Bouma (Brett); P.M. Villiger (Peter M.); H.M. Garcia-Garcia (Hector); P.W.J.C. Serruys (Patrick); F. Zijlstra (Felix); G. van Soest (Gijs); D.J.G.M. Duncker (Dirk); E.S. Regar (Eveline); H.M.M. van Beusekom (Heleen)

    2017-01-01

    textabstractBackground: DM remains a risk factor for poor outcome after stent-implantation, but little is known if and how DM affects the vascular response to BVS. Aim: The aim of our study was to examine coronary responses to bioresorbable vascular scaffolds (BVS) in

  1. Asymmetric Branching in Biological Resource Distribution Networks

    Science.gov (United States)

    Brummer, Alexander Byers

    There is a remarkable relationship between an organism's metabolic rate (resting power consumption) and the organism's mass. It may be a universal law of nature that an organism's resting metabolic rate is proportional to its mass to the power of 3/4. This relationship, known as Kleiber's Law, appears to be valid for both plants and animals. This law is important because it implies that larger organisms are more efficient than smaller organisms, and knowledge regarding metabolic rates are essential to a multitude of other fields in ecology and biology. This includes modeling the interactions of many species across multiple trophic levels, distributions of species abundances across large spatial landscapes, and even medical diagnostics for respiratory and cardiovascular pathologies. Previous models of vascular networks that seek to identify the origin of metabolic scaling have all been based on the unrealistic assumption of perfectly symmetric branching. In this dissertation I will present a theory of asymmetric branching in self-similar vascular networks (published by Brummer et al. in [9]). The theory shows that there can exist a suite of vascular forms that result in the often observed 3/4 metabolic scaling exponent of Kleiber's Law. Furthermore, the theory makes predictions regarding major morphological features related to vascular branching patterns and their relationships to metabolic scaling. These predictions are suggestive of evolutionary convergence in vascular branching. To test these predictions, I will present an analysis of real mammalian and plant vascular data that shows: (i) broad patterns in vascular networks across entire animal kingdoms and (ii) within these patterns, plant and mammalian vascular networks can be uniquely distinguished from one another (publication in preparation by Brummer et al.). I will also present results from a computational study in support of point (i). Namely, that asymmetric branching may be the optimal strategy to

  2. 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...

  3. Prospective multi-center registry to evaluate efficacy and safety of the newly developed diamond-like carbon-coated cobalt-chromium coronary stent system.

    Science.gov (United States)

    Ando, Kenji; Ishii, Katsuhisa; Tada, Eiji; Kataoka, Kazuaki; Hirohata, Atsushi; Goto, Kenji; Kobayashi, Katsuyuki; Tsutsui, Hiroshi; Nakahama, Makoto; Nakashima, Hitoshi; Uchikawa, Shinichiroh; Kanda, Junji; Yasuda, Satoshi; Yajima, Junji; Kitabayashi, Hiroshi; Sakurai, Shumpei; Nakanishi, Keita; Inoue, Naoto; Noike, Hirofumi; Hasebe, Terumitsu; Sato, Tetsuya; Yamasaki, Masao; Kimura, Takeshi

    2017-07-01

    The purpose of this multi-center, non-randomized, and open-label clinical trial was to determine the non-inferiority of diamond-like carbon (DLC)-coated cobalt-chromium coronary stent, the MOMO DLC coronary stent, relative to commercially available bare-metal stents (MULTI-LINK VISION®). Nineteen centers in Japan participated. The study cohort consisted of 99 patients from 19 Japanese centers with single or double native coronary vessel disease with de novo and restenosis lesions who met the study eligibility criteria. This cohort formed the safety analysis set. The efficacy analysis set consisted of 98 patients (one case was excluded for violating the eligibility criteria). The primary endpoint was target vessel failure (TVF) rate at 9 months after stent placement. Of the 98 efficacy analysis set patients, TVF occurred in 11 patients (11.2 %, 95 % confidence interval 5.7-19.2 %) at 9 months after the index stent implantation. The upper 95 % confidence interval for TVF of the study stent was lower than that previously reported for the commercially available MULTI-LINK VISION® (19.6 %), demonstrating non-inferiority of the study stent to MULTI-LINK VISION®. All the TVF cases were related to target vascular revascularization. None of the cases developed in-stent thrombosis or myocardial infarction. The average in-stent late loss and binary restenosis rate at the 6-month follow-up angiography were 0.69 mm and 10.5 %, respectively, which are lower than the reported values for commercially available bare-metal stents. In conclusion, the current pivotal clinical study evaluating the new MOMO DLC-coated coronary stent suggested its low rates of TVF and angiographic binary restenosis, and small in-stent late loss, although the data were considered preliminary considering the small sample size and single arm study design.

  4. Asymmetrical field emitter

    Science.gov (United States)

    Fleming, J.G.; Smith, B.K.

    1995-10-10

    A method is disclosed for providing a field emitter with an asymmetrical emitter structure having a very sharp tip in close proximity to its gate. One preferred embodiment of the present invention includes an asymmetrical emitter and a gate. The emitter having a tip and a side is coupled to a substrate. The gate is connected to a step in the substrate. The step has a top surface and a side wall that is substantially parallel to the side of the emitter. The tip of the emitter is in close proximity to the gate. The emitter is at an emitter potential, and the gate is at a gate potential such that with the two potentials at appropriate values, electrons are emitted from the emitter. In one embodiment, the gate is separated from the emitter by an oxide layer, and the emitter is etched anisotropically to form its tip and its asymmetrical structure. 17 figs.

  5. Removal of a partially covered stent by endoscopic substent dissection

    Directory of Open Access Journals (Sweden)

    Iyad Khamaysi

    2016-01-01

    Full Text Available Herein we describe a new technical endoscopic removal of embedded partially covered esophageal stent that was inserted to treat a iatrogenic perforation of esophagus. Usually, partially covered stents can be removed by the stent-in-stent technique. In this case, the embedded stent could not be removed safely with this technique; so we performed a sub stent dissection to detach the stent from the esophageal wall.

  6. Percutaneous coronary angioscopy and stents

    Science.gov (United States)

    Heuser, Richard R.

    1994-05-01

    With the expanding array of therapies available for coronary intervention, the invasive cardiologist has many choices for treating a specific lesion in an individual patient. Certain types of lesions might respond more effectively with stents, particularly the rigid Palmax- Schatz device. Thrombus and dissection immediately following stent placement are associated with early occlusion, and the interventionist must be able to assess their presence pre- and post-stenting. Angiography is deficient in quantifying minimal disease and in defining lesion architecture and composition, as well as the plaque rupture and thrombosis associated with unstable angina. It is also imprecise in detecting dissection and thrombus. Intravascular ultrasound (IVUS) provides high-resolution images that delineate irregularities and other structures inside the lumen and within the vessel wall and surrounding tissues. Like angiography, IVUS has limited specificity for thrombus differentiation. Angioscopy is superior to angiography and IVUS in detecting thrombus and dissection. Angioscopy allows the clinician to assess the appearance of stent struts after deployment and at follow-up. This may aid in reducing acute complications as well as restenosis. Follow-up angioscopy of stents to detect thrombus or exposed struts may guide therapy in a patient who has clinical symptoms of restenosis.

  7. Extracellular Matrix Molecules Facilitating Vascular Biointegration

    Directory of Open Access Journals (Sweden)

    Martin K.C. Ng

    2012-08-01

    Full Text Available All vascular implants, including stents, heart valves and graft materials exhibit suboptimal biocompatibility that significantly reduces their clinical efficacy. A range of biomolecules in the subendothelial space have been shown to play critical roles in local regulation of thrombosis, endothelial growth and smooth muscle cell proliferation, making these attractive candidates for modulation of vascular device biointegration. However, classically used biomaterial coatings, such as fibronectin and laminin, modulate only one of these components; enhancing endothelial cell attachment, but also activating platelets and triggering thrombosis. This review examines a subset of extracellular matrix molecules that have demonstrated multi-faceted vascular compatibility and accordingly are promising candidates to improve the biointegration of vascular biomaterials.

  8. Early outcomes after carotid angioplasty with stenting performed by neurologists

    Directory of Open Access Journals (Sweden)

    Bathala Lokesh

    2010-01-01

    Full Text Available Aims: To evaluate the results of carotid artery angioplasty and stenting (CAS in treating extracranial carotid artery stenosis performed by neurologists in our center and compare the results with other large published series. Materials and Methods: Data for all patients who underwent CAS from January 2003 through November 2007, was retrieved from the Nanjing Stroke Registry. Perioperative and post-procedural complications within 30 days following stenting were analyzed and compared with that from other series. A total number of 75 patients were enrolled, with a mean age of 65.9 ± 8.8 years, and 64 (85.3% of them were male. Results: Procedural success was achieved in 74 patients (98.7%. Pre-treatment stenosis was 73.8 ± 14.9 and post-treatment residual stenosis was less than 10%. Thirty-four patients (45.3% had bilateral carotid artery disease and seven (9.3% had tandem stenosis. The neurological complication rate was 3.9% (one major and two minor strokes. Bradycardia in four (5.3% and hypotension in 13 (17.3% were observed during procedures. Using the Fischer′s exact t test, the complication rate compared with the large published series did not reveal any statistically significant difference (P > 0.05. Conclusions: We conclude that neurologists, with adequate training, can develop and add this technical skill to the existing cognitive skill of vascular neurology and safely perform stenting.

  9. Long-term clinical and economic analysis of the Endeavor drug-eluting stent versus the Driver bare-metal stent: 4-year results from the ENDEAVOR II trial (Randomized Controlled Trial to Evaluate the Safety and Efficacy of the Medtronic AVE ABT-578 Eluting Driver Coronary Stent in De Novo Native Coronary Artery Lesions).

    Science.gov (United States)

    Eisenstein, Eric L; Wijns, William; Fajadet, Jean; Mauri, Laura; Edwards, Rex; Cowper, Patricia A; Kong, David F; Anstrom, Kevin J

    2009-12-01

    This study was designed to evaluate long-term clinical and economic outcomes for subjects receiving Endeavor drug-eluting versus Driver bare-metal stents (both Medtronic CardioVascular, Santa Rosa, California). Early studies found that the drug-eluting stent (DES) was a clinically and economically attractive alternative to the bare-metal stent; however, associations between DES and very late stent thrombosis suggest that longer follow-up is required. We used clinical, resource use and follow-up data from 1,197 subjects randomized to receive Endeavor (n = 598) versus Driver (n = 599) stents in ENDEAVOR II (Randomized Controlled Trial to Evaluate the Safety and Efficacy of the Medtronic AVE ABT-578 Eluting Driver Coronary Stent in De Novo Native Coronary Artery Lesions) study with Medicare cost weights and quality of life adjustments applied from secondary sources. We compared differences through 4-year follow-up (1,440 days). Patients in both treatment groups had similar baseline characteristics. The use of Endeavor versus Driver reduced 4-year target vessel revascularization rates per 100 subjects (10.4 vs. 21.5; difference: -11.1; 95% confidence interval [CI]: -16.0 to -6.1; p AVE ABT-578 Eluting Driver Coronary Stent in De Novo Native Coronary Artery Lesions [ENDEAVOR II]; NCT00614848).

  10. Asymmetrical international attitudes

    NARCIS (Netherlands)

    Van Oudenhoven, JP; Askevis-Leherpeux, F; Hannover, B; Jaarsma, R; Dardenne, B

    2002-01-01

    In general, attitudes towards nations have a fair amount of reciprocity: nations either like each other are relatively indifferent to each other or dislike each other Sometimes, however international attitudes are asymmetrical. In this study, we use social identity theory in order to explain

  11. How Is Nature Asymmetric?

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 7; Issue 6. How Is Nature Asymmetric? - Discrete Symmetries in Particle Physics and their Violation ... Indian Institute of Technology, Chennai. Aligarh Muslim University. University of Rajasthan, Jaipur. Indian Institute of Science, Bangalore 560012, India.

  12. Indications for stenting during thrombolysis

    DEFF Research Database (Denmark)

    Bækgaard, N; Broholm, R; Just, Sven Richardt Lundgren

    2013-01-01

    The most important vein segment to thrombolyse after deep venous thrombosis (DVT) is the outflow tract meaning the iliofemoral vein. Iliofemoral DVT is defined as DVT in the iliac vein and the common femoral vein. Spontaneous recanalization is less than 50%, particularly on the left side...... of a stent in this position is the treatment of choice facilitating the venous flow into an unobstructed outflow tract either from the femoral vein or the deep femoral vein or both. The stent, made of stainless steel or nitinol, has to be self-expandable and flexible with radial force to overcome...... with catheter-directed thrombolysis of iliofemoral deep venous thrombosis....

  13. 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.

  14. Configuration-space technique for calculating stent-fitness measures for the planning of neuro-endovascular interventions

    Science.gov (United States)

    Kesavadas, Thenkurussi; Agrawal, Rajendra; Hoffmann, Kenneth R.

    2005-04-01

    This paper demonstrates a new technique to compute stent-fitness measures for a vascular anatomy, using geometric information. This technique will aid the interventionalist in treatment planning for Neuro-endovascular interventions. Patient-specific vessel-surface reconstruction is performed from point/contour data without user intervention. The technique developed is based on configuration-space algorithms, which are widely used in robot motion planning. A fitness measure is computed for stents with various parameters for a patient-specific vessel data. Finally, a simulation is performed to check for collisions. This feature will provide an additional tool to the interventionalist for the planning of neuro-endovascular interventions, with the dimensions of the stent based on proximal and distal neck of the aneurysm for a patient-specific vascular anatomy.

  15. Highly asymmetric rice genomes

    Directory of Open Access Journals (Sweden)

    Chen Jian-Qun

    2007-06-01

    Full Text Available Abstract Background Individuals in the same species are assumed to share the same genomic set. However, it is not unusual to find an orthologous gene only in small subset of the species, and recent genomic studies suggest that structural rearrangements are very frequent between genomes in the same species. Two recently sequenced rice genomes Oryza sativa L. var. Nipponbare and O. sativa L. var. 93-11 provide an opportunity to systematically investigate the extent of the gene repertoire polymorphism, even though the genomic data of 93-11 derived from whole-short-gun sequencing is not yet as complete as that of Nipponbare. Results We compared gene contents and the genomic locations between two rice genomes. Our conservative estimates suggest that at least 10% of the genes in the genomes were either under presence/absence polymorphism (5.2% or asymmetrically located between genomes (4.7%. The proportion of these "asymmetric genes" varied largely among gene groups, in which disease resistance (R genes and the RLK kinase gene group had 11.6 and 7.8 times higher proportion of asymmetric genes than housekeeping genes (Myb and MADS. The significant difference in the proportion of asymmetric genes among gene groups suggests that natural selection is responsible for maintaining genomic asymmetry. On the other hand, the nucleotide diversity in 17 R genes under presence/absence polymorphism was generally low (average nucleotide diversity = 0.0051. Conclusion The genomic symmetry was disrupted by 10% of asymmetric genes, which could cause genetic variation through more unequal crossing over, because these genes had no allelic counterparts to pair and then they were free to pair with homologues at non-allelic loci, during meiosis in heterozygotes. It might be a consequence of diversifying selection that increased the structural divergence among genomes, and of purifying selection that decreased nucleotide divergence in each R gene locus.

  16. The REMEDEE-OCT Study: An Evaluation of the Bioengineered COMBO Dual-Therapy CD34 Antibody-Covered Sirolimus-Eluting Coronary Stent Compared With a Cobalt-Chromium Everolimus-Eluting Stent in Patients With Acute Coronary Syndromes: Insights From Optical Coherence Tomography Imaging Analysis.

    Science.gov (United States)

    Jaguszewski, Milosz; Aloysius, Romila; Wang, Wei; Bezerra, Hiram G; Hill, Jonathan; De Winter, Robbert J; Karjalainen, Pasi P; Verheye, Stefan; Wijns, William; Lüscher, Thomas F; Joner, Michael; Costa, Marco; Landmesser, Ulf

    2017-03-13

    The aim of the present study was to evaluate vascular healing of the bioengineered COMBO Dual Therapy Stent compared with a cobalt-chromium (CoCr) everolimus-eluting stent (EES) as assessed by optical coherence tomography in patients with acute coronary syndromes. CD34+ cells promote endothelial repair after vascular injury. The bioengineered COMBO Dual Therapy Stent combines CD34+ cell-capturing technology with abluminal sirolimus release, but more data from clinical studies evaluating the vascular response are needed. In a prospective randomized multicenter clinical trial, 60 patients with acute coronary syndromes were randomized 1:1 to COMBO or CoCr EES implantation. The primary endpoint was the percentage of uncovered stent struts per stent. Stent assessment by optical coherence tomography was performed at baseline and at 60 days, followed by independent core laboratory analysis. The percentage of uncovered struts per stent was higher with the COMBO than the CoCr EES at 60 days (median 14.7% vs. 7.7%; p = 0.04). However, no significant difference in uncovered stent struts was observed in the strut level-based analysis at 60 days, which also accounted for clustering (COMBO vs. CoCr EES; 13.6% vs. 6.9%; p = 0.09; generalized linear mixed models-adjusted analysis). Neointimal thickness at 60 days was lower with the COMBO compared with the CoCr EES (median 30.17 vs. 50.26 μm; p = 0.02; stent-level analysis). There were no significant differences in the frequency of major adverse cardiac events and each component of major adverse cardiac events within the study population between the 2 groups at 30, 60, 180, 360, and 540 days post-procedure. No target vessel stent thrombosis has been documented within 540 days. The present multicenter, prospective clinical study for the first time compared the vascular response of the bioengineered COMBO Dual Therapy Stent with a CoCr EES in patients early after acute coronary syndrome by using intracoronary optical coherence

  17. COmplex coronary Bifurcation lesions: RAndomized comparison of a strategy using a dedicated self-expanding biolimus-eluting stent versus a culotte strategy using everolimus-eluting stents: primary results of the COBRA trial.

    Science.gov (United States)

    Dubois, Christophe; Bennett, Johan; Dens, Joseph; De Cock, Dries; Desmet, Walter; Belmans, Ann; Ughi, Giovanni J; Sinnaeve, Peter; Vrolix, Mathias; D'hooge, Jan; Adriaenssens, Tom

    2016-04-20

    We aimed to compare healing responses with optical coherence tomography, and clinical and angiographic outcome after treatment of coronary bifurcation lesions with a dedicated stent versus a conventional culotte technique. Forty patients with true and complex coronary bifurcation lesions were randomly assigned to treatment with the Axxess™ bifurcation stent in the proximal main vessel (MV) and additional BioMatrix™ stents in the branches (Biosensors Europe SA, Morges, Switzerland), versus a culotte technique using XIENCE™ stents (Abbott Vascular, Santa Clara, CA, USA). The primary endpoint of percentage of uncovered struts at nine months was similar with the dedicated strategy vs. culotte in the proximal MV (median 17.8 [IQR 3.3-24.7] vs. 6.8 [2.0-20.5]; p=0.19), bifurcation core (9.5 [5.7-19.5] vs. 4.0 [0.7-17.6]; p=0.17), distal MV (2.6 [2.3-18] vs. 2.2 [0.5-6.0]; p=0.09) and side branch (5.7 [1.5-11.5] vs. 1.9 [0-5.8]; p=0.14). As compared with culotte, a strategy using Axxess resulted in a significantly larger lumen in the proximal MV both acutely (minimum lumen diameter 3.03±0.51 vs. 2.71±0.44 mm, p=0.04) and at follow-up (mean lumen area 10.0±2.1 vs. 7.1±1.8 mm2, pstrategies resulted in good clinical outcomes at one year, and no stent thromboses. As compared with a culotte strategy with XIENCE stents, complex bifurcation stenting using a dedicated strategy combining Axxess and BioMatrix stents results in similar stent strut coverage at nine-month follow-up, and a significantly larger lumen and lower angiographic late lumen loss in the proximal MV.

  18. Everolimus-eluting bioresorbable stent vs. durable polymer everolimus-eluting metallic stent in patients with ST-segment elevation myocardial infarction: Results of the randomized ABSORB ST-segment elevation myocardial infarction-TROFI II trial

    NARCIS (Netherlands)

    M. Sabate (Manel); S.W. Windecker (Stephan); A. Iiguez (Andres); Okkels-Jensen, L. (Lisette); A. Cequier; S. Brugaletta (Salvatore); S.H. Hofma (Sjoerd); L. Räber (Lorenz); Christiansen, E.H. (Evald Høi); M.J. Suttorp (Maarten); T. Pilgrim (Thomas); G.A. van Es (Gerrit Anne); Y. Sotomi (Yohei); H.M. Garcia-Garcia (Hector); Y. Onuma (Yoshinobu); P.W.J.C. Serruys (Patrick)

    2016-01-01

    textabstractAims: Patients with ST-segment elevation myocardial infarction (STEMI) feature thrombus-rich lesions with large necrotic core, which are usually associated with delayed arterial healing and impaired stent-related outcomes. The use of bioresorbable vascular scaffolds (Absorb) has the

  19. Everolimus-eluting bioresorbable stent vs. durable polymer everolimus-eluting metallic stent in patients with ST-segment elevation myocardial infarction: results of the randomized ABSORB ST-segment elevation myocardial infarction-TROFI II trial

    NARCIS (Netherlands)

    Sabaté, Manel; Windecker, Stephan; Iñiguez, Andres; Okkels-Jensen, Lisette; Cequier, Angel; Brugaletta, Salvatore; Hofma, Sjoerd H.; Räber, Lorenz; Christiansen, Evald Høi; Suttorp, Maarten; Pilgrim, Thomas; Anne van Es, Gerrit; Sotomi, Yohei; García-García, Hector M.; Onuma, Yoshinobu; Serruys, Patrick W.

    2016-01-01

    Patients with ST-segment elevation myocardial infarction (STEMI) feature thrombus-rich lesions with large necrotic core, which are usually associated with delayed arterial healing and impaired stent-related outcomes. The use of bioresorbable vascular scaffolds (Absorb) has the potential to overcome

  20. [Vascular dementia

    NARCIS (Netherlands)

    Leeuw, H.F. de; Gijn, J. van

    2004-01-01

    Vascular dementia is one of the most frequently occurring dementia syndromes. Its prevalence is about 5% among subjects above 85 years of age. Elevated blood pressure and atherosclerosis are the most important risk factors. According to international criteria, vascular dementia usually occurs within

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

    Directory of Open Access Journals (Sweden)

    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.

  2. 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.

  3. Vascular restoration: Is there a window of opportunity?

    Science.gov (United States)

    Sun, Jianhua; Kang, Xiaoran; Li, Tianzhu

    2015-12-01

    The usage of drug eluting stents (DES) has markedly reduced the rates of coronary revascularization procedures compared with bare metal stents (BMS). However, this technology still faces challenges in terms of the prevention of late stent thrombosis, major adverse cardiac events (MACE) progression, and the catch-up phenomenon of restenosis. Restoration of endothelial function upon after stenting, therefore, is the key to mitigating the risk of these toxicities and determining the level of the efficacy and safety of an implant. Review of the clinical studies of multiple DES, has suggested that there exists a window of opportunity, within the first two to three months after stent implantation, for restoring vascular function. If re-endothelialization reaches sufficient level within this period, vascular restoration can occur; however, if this opportunity is missed, re-endothelialization is unlikely to reach the level of endothelial maturation necessary to prevent the late stent thrombosis, MACE progression and the catch-up on restenosis. This hypothesis could aid in explaining variable clinical responses for revascularization treatments such as plain old balloon angioplasty (POBA), BMS, or DES. Patients could be grouped according to responses to the different treatment modalities: for Type 1 patients, POBA is sufficient and safe because they possess the capacity with effective endothelial response; for Type 2 patients, re-endothelialization occurs within the window but BMS are needed to maintain the arterial lumen open; for Type 3 individuals, overly accelerated vascular smooth muscle proliferation render sufficient re-endothelialization impossible. Designing based on this principle predicts that the next technology advancement for the interventional cardiology will not be biodegradable DES by default, but rather a DES that can spur early restoration of the endothelial function within the window period. Copyright © 2015 Elsevier Ltd. All rights reserved.

  4. Circumferential stent fracture repaired using a covered stent in a 42-year-old man with coarctation of the aorta.

    Science.gov (United States)

    Ayoub, Fares; AlShelleh, Sameeha; A L-Ammouri, Iyad

    2016-02-01

    We present a case of circumferential fracture of aortic coarctation stent with severe re-stentosis presenting 16 years after initial stent implantation with end-stage renal disease. The patient was treated with a covered stent using the stent-in-stent technique. The use of an ultra-high-pressure balloon was proved necessary to overcome the tight, non-compliant stenosis.

  5. Endovascular stent placement of juxtaanastomotic stenosis in native arteriovenous fistula after unsuccessful balloon angioplasty.

    Science.gov (United States)

    Ozkan, Burak; Güngör, Durmus; Yıldırım, Utku Mahir; Harman, Ali; Ozen, Ozgur; Aytekin, Cüneyt

    2013-09-01

    In hemodialysis patients, the most common problem in arteriovenous fistulas, as the best functional vascular access, is the juxtaanastomotic located lesions. Percutaneous transluminal angioplasty is accepted as the treatment method for juxtanastomotic lesions. To assess juxtaanastomotic stent placement after insufficient balloon angioplasty in the treatment of autogenous radiocephalic or brachiocephalic fistula dysfunction. Between July 2003 and June 2010, 20 hemodialysis patients with autogenous radiocephalic or brachiocephalic fistula dysfunction underwent stent placement for the lesion located at the juxtaanastomotic region. Indications for stent placement were insufficient balloon dilatation, early recurring stenosis, chronic organizing thrombus and vessel rupture. The Kaplan-Meier method was used to calculate the stent patency rates. All patients who had fistula dysfunction (thrombosis of hemodialysis access, difficult access cannulation, extremity pain due to thrombosis or decreased arterial access blood flow) were evaluated by color Doppler ultrasound. The stenoses were initially dilated with standard noncompliant balloons (3 to 10-mm in diameter). Dilatation was followed by high pressure (Blue Max, Boston Scientific) or cutting balloons (Boston Scientific), if the standard balloon failed to dilate the stenotic segment. Twenty-one stents were applied. The anatomical and clinical success rate was 100%. Seventeen additional interventions were done for 11 (55%) patients due to stent thrombosis or stenosis during follow-up. Our 1- and 2-year secondary patency rates were 76.2% and 65.5%, respectively and were comparable to those after balloon angioplasty and surgical shunt revision. Metallic stent placement is a safe and effective procedure for salvage of native hemodialysis fistula after unsuccessful balloon angioplasty.

  6. 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 differe...

  7. Editor's Choice - Effect of Branch Stent Choice on Branch-related Outcomes in Complex Aortic Repair.

    Science.gov (United States)

    Mastracci, T M; Carrell, T; Constantinou, J; Dias, N; Martin-Gonzalez, T; Katsargyris, A; Modarai, B; Resch, T; Verhoeven, E L G; Burnell, M; Haulon, S

    2016-04-01

    The use of branched stent grafts for the treatment of thoracoabdominal aneurysms [TAAA] is increasing, but mating stent graft choice has not been studied. This study combined experience of five high volume centres to assess a preferred mating stent. Data from five centres were retrospectively combined. Patients were included if they underwent stent graft for treatment of TAAA that used only branches to mate with visceral and renal vessels. All patients with fenestrations in their device were excluded. Perioperative details, reintervention, occlusion, and death were recorded. Outcome of occlusion or reintervention, as well as a composite outcome of any death, occlusion, or reintervention was planned using a per-patient, and per-branch analysis. In 235 included patients, there were 940 vessels available for placement of mating stent. The average age of included patients was 70 years (SD 7.9), and 179 of the 235 were male. Medical comorbidities included diabetes in 29/234 (12.4%), current smoker in 81/233 (34.8%), and COPD in 77/234 (32.9%). The primary stent deployed was self-expanding in 556 branches, balloon expandable in 231 branches, and was unknown in 92 branches. After a mean of 20.7 months (SD 25) follow-up, there have been 44 incidents of occlusion or reintervention, of which 40 culprit stents are known. Where the stent placed is known, the event rate in renal branches (35/437, 8%) is higher than that of visceral branches (8/443, 1.8%). There is no difference in occlusion or reintervention between self-expanding and balloon expandable stents (HR 0.95, p = .91) but there is a statistically significant difference between renal and visceral artery occlusions (HR 3.51, p = 0.001). There appears to be no difference in occlusion or reintervention rate for branch vessels mated with balloon expandable compared with self-expanding stents. Renal events appear to outnumber visceral events in this population. Copyright © 2016 European Society for Vascular Surgery

  8. Self-expanding nitinol stents of high versus low chronic outward force in de novo femoropopliteal occlusive arterial lesions (BIOFLEX-COF trial): study protocol for a randomized controlled trial.

    Science.gov (United States)

    Wressnegger, Alexander; Kaider, Alexandra; Funovics, Martin A

    2017-12-14

    Self-expanding nitinol stents must be oversized at least by a minimal amount to ensure contact with the vessel wall and prevent migration. Once the stent is deployed it exerts a continuous force upon the vascular wall, termed chronic outward force (COF). Animal studies have found an increased neointimal hyperplasia in stents with high oversizing and thus high COF. Data about correlation between COF and neointimal hyperplasia in humans are currently lacking. The objective of the BIOFLEX-COF trial is to prospectively investigate differences in formation of intimal hyperplasia at 1 and 2 years after implantation of nitinol stents with high versus low COF in de novo femoropopliteal occlusive arterial lesions. The BIOFLEX-COF trial is a prospective, quantitative, randomized study. Eighty subjects with symptomatic peripheral arterial lesions eligible for endovascular stent implantation will be enrolled and randomly assigned to either a high COF group (LifeStent Flexstar, Bard Peripheral Vascular Inc., Tempe, AZ, USA) or low COF group (Pulsar, Biotronik AG, Bülach, Switzerland) using an online randomization program to generate a random 1:1 group allocation (block randomization). After implantation and dilatation, COF at every 2 mm along the stent axis will be calculated from the actual stent diameter versus its nominal diameter. There will be two follow-up evaluations at 12 and 24 months. Primary endpoint is the amount of in-stent neointima at 1 year, assessed by contrast-enhanced CT angiography (CTA). In the control examinations, stent diameter and true lumen diameter will be measured on DICOM images every 2 mm along the stent axis to quantify the relative amount of in-stent restenosis. Secondary objectives are the amount of in-stent neointima at 2 years, device- and procedure-related adverse events and target lesion revascularization (TLR) rate. The scheduled time for recruitment is 2 years. Recruitment is expected to be complete in October 2017. This trial is the

  9. [Therapeutic effect of Cheatham-Platinum stent implantation for vessel stenosis associated with congenital heart disease in children and adolescents].

    Science.gov (United States)

    Li, Fen; Zhou, Ai-Qing; Gao, Wei; Yu, Zhi-Qing; Sun, Kun; Huang, Mei-Rong; Li, Yun; Yang, Jian-Ping; Zhao, Wu

    2009-04-01

    Although NuMED Cheatham-Platinum (CP) stent was specifically designed to treat vascular obstructions associated with congenital heart disease (CHD), its application in pediatric patients is relatively uncommon, especially in the pulmonary artery stenosis. The aim of this study was to evaluate the immediate-, early- and intermediate-term results of CP stent implantation in the treatment of vessel stenosis associated with CHD in children and adolescents. From August 2005 to May 2007, 5 consecutive patients (3 boys and 2 girls) diagnosed as vascular stenosis associated with CHD underwent CP stent implantation in our institution. One patient had native coarctation of the aorta (CoA) and four patients had pulmonary artery stenosis. The median age and weight of patients were 12 years (range 4 - 15 years) and 24 kg (range 20 - 51 kg), respectively. The CP stent and NuMED Balloon-in-Balloon catheter were selected according to digital subtracted angiography measurements. After checking for correct position by angiography, the inner balloon and outer balloon inflated successively to expand the stent to desired diameter. Totally 6 stent placement procedures were performed and 8 CP stents (8-zig, 22 - 39 mm in length) were implanted in these 5 patients. All stents but one in a case of right pulmonary artery stenosis were immediately successfully placed in the target lesions without displacement during the procedures. For this case, a repeat procedure was performed and a second CP stent was reimplanted successfully 11 months later. After the procedure, the systolic pressure gradient across the stenosis decreased from (43.43 +/- 25.61) mm Hg (1 mm Hg = 0.133 kPa) to (3.29 +/- 3.09) mm Hg (t = 4.320, P stenosis, respectively. The ratio of right ventricular to aortic systolic pressure decreased from 62.3% and 72.2% to 27.0% and 33.3% in 2 cases of bilateral branch pulmonary artery stenosis, respectively. Upper limb blood pressure of one case of native CoA dropped greatly from 206

  10. 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.

  11. Occurrence and predictors of acute stent recoil-A comparison between the xience prime cobalt chromium stent and the promus premier platinum chromium stent.

    Science.gov (United States)

    van Bommel, Rutger J; Lemmert, Miguel E; van Mieghem, Nicolas M; van Geuns, Robert-Jan; van Domburg, Ron T; Daemen, Joost

    2017-05-13

    To compare the occurrence of acute stent recoil in two different stent types (platinum chromium and cobalt chromium) and identify the potential predictors of significant acute stent recoil. Acute stent recoil is frequently observed after percutaneous coronary intervention and has been associated with in-stent restenosis and in-stent thrombosis. Different stent designs may result in varying degrees of stent recoil. From a registry of "all-comers" treated with either the Xience Prime Cobalt Chromium or Promus Premier Platinum Chromium stent, a random sample of 100 patients was drawn. Acute stent recoil was defined as the minimal luminal diameter (MLD) of the last inflated balloon minus the MLD after, divided by the MLD of the last inflated balloon. Significant acute stent recoil was defined as recoil ≥10%. A total of 123 lesions (61 Xience Prime vs 62 Promus Premier) in 100 patients were analyzed. Acute stent recoil of 8.6 ± 4.9% was observed in the Xience Prime group versus 8.7 ± 4.2% in the Promus Premier group, P = 0.970. In a multivariate model for significant acute stent recoil, a stent/vessel ratio ≥1 (hazard ratio 4.64 [1.94-11.12], P = 0.001), a balloon/stent ratio >1 (hazard ratio 3.83 [1.12-13.14], P = 0.032) and direct stenting (hazard ratio 0.42 [0.18-0.96], P = 0.039) were identified as predictors. No significant differences were observed in the extent of acute stent recoil between the Xience Prime and the Promus Premier stent. A larger stent/vessel ratio, a larger balloon/stent ratio, and direct stenting were associated with significant acute stent recoil ≥10%. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  12. Comparison of an everolimus-eluting bioresorbable scaffold with an everolimus-eluting metallic stent for the treatment of coronary artery stenosis (ABSORB II)

    DEFF Research Database (Denmark)

    Serruys, Patrick W; Chevalier, Bernard; Sotomi, Yohei

    2016-01-01

    BACKGROUND: No medium-term data are available on the random comparison between everolimus-eluting bioresorbable vascular scaffolds and everolimus-eluting metallic stents. The study aims to demonstrate two mechanistic properties of the bioresorbable scaffold: increase in luminal dimensions......-novo native lesions in different epicardial vessels. We randomly assigned patients (2:1) to receive treatment with an everolimus-eluting bioresorbable scaffold (Absorb; Abbott Vascular, Santa Clara, CA, USA) or treatment with an everolimus-eluting metallic stent (Xience; Abbott Vascular, Santa Clara, CA, USA......). Randomisation was stratified by diabetes status and number of planned target lesions. At 3 year follow-up, the primary endpoint was superiority of the Absorb bioresorbable scaffold versus the Xience metallic stent in angiographic vasomotor reactivity after administration of intracoronary nitrate. The co...

  13. Vascular Complications of Pancreatitis: Role of Interventional Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Barge, Jaideep U.; Lopera, Jorge E. [University of Texas Health Science Center, San Antonio (United States)

    2012-02-15

    Major vascular complications related to pancreatitis can cause life-threatening hemorrhage and have to be dealt with as an emergency, utilizing a multidisciplinary approach of angiography, endoscopy or surgery. These may occur secondary to direct vascular injuries, which result in the formation of splanchnic pseudoaneurysms, gastrointestinal etiologies such as peptic ulcer disease and gastroesophageal varices, and post-operative bleeding related to pancreatic surgery. In this review article, we discuss the pathophysiologic mechanisms, diagnostic modalities, and treatment of pancreatic vascular complications, with a focus on the role of minimally-invasive interventional therapies such as angioembolization, endovascular stenting, and ultrasound-guided percutaneous thrombin injection in their management.

  14. What Are the Risks of Having a Stent?

    Science.gov (United States)

    ... What Are the Risks of Having a Stent? Risks Related to Percutaneous Coronary Intervention Percutaneous coronary intervention ( ... section of the tissue growth around the stent. Risks Related to Stents About 1–2 percent of ...

  15. Vascular ring

    DEFF Research Database (Denmark)

    Schmidt, Anne Mette S; Larsen, Signe H; Hjortdal, Vibeke E

    2018-01-01

    BACKGROUND: Vascular ring is a rare cause of recurrent respiratory infections, dysphagia and stridor. Surgical repair is considered safe but the long-term outcomes are unclear. The purpose of this study was to investigate the mortality and morbidity following vascular ring surgery in a single...... age of 1.4 years (range 0.008-64 years) were operated for vascular ring. Median follow-up was 6.8 years (range 2.4-34 years). Presenting symptoms were stridor (52%), dysphagia or vomiting (52%) and recurrent respiratory infections (48%). There were no early or late deaths. Three months postoperatively...

  16. Asymmetric extractions in orthodontics

    Directory of Open Access Journals (Sweden)

    Camilo Aquino Melgaço

    2012-04-01

    Full Text Available INTRODUCTION: Extraction decisions are extremely important in during treatment planning. In addition to the extraction decision orthodontists have to choose what tooth should be extracted for the best solution of the problem and the esthetic/functional benefit of the patient. OBJECTIVE: This article aims at reviewing the literature relating the advantages, disadvantages and clinical implications of asymmetric extractions to orthodontics. METHODS: Keywords were selected in English and Portuguese and the EndNote 9 program was used for data base search in PubMed, Web of Science (WSc and LILACS. The selected articles were case reports, original articles and prospective or retrospective case-control studies concerning asymmetrical extractions of permanent teeth for the treatment of malocclusions. CONCLUSION: According to the literature reviewed asymmetric extractions can make some specific treatment mechanics easier. Cases finished with first permanent molars in Class II or III relationship in one or both sides seem not to cause esthetic or functional problems. However, diagnosis knowledge and mechanics control are essential for treatment success.

  17. Asymmetric Evolutionary Games.

    Directory of Open Access Journals (Sweden)

    Alex McAvoy

    2015-08-01

    Full Text Available Evolutionary game theory is a powerful framework for studying evolution in populations of interacting individuals. A common assumption in evolutionary game theory is that interactions are symmetric, which means that the players are distinguished by only their strategies. In nature, however, the microscopic interactions between players are nearly always asymmetric due to environmental effects, differing baseline characteristics, and other possible sources of heterogeneity. To model these phenomena, we introduce into evolutionary game theory two broad classes of asymmetric interactions: ecological and genotypic. Ecological asymmetry results from variation in the environments of the players, while genotypic asymmetry is a consequence of the players having differing baseline genotypes. We develop a theory of these forms of asymmetry for games in structured populations and use the classical social dilemmas, the Prisoner's Dilemma and the Snowdrift Game, for illustrations. Interestingly, asymmetric games reveal essential differences between models of genetic evolution based on reproduction and models of cultural evolution based on imitation that are not apparent in symmetric games.

  18. Asymmetric Evolutionary Games.

    Science.gov (United States)

    McAvoy, Alex; Hauert, Christoph

    2015-08-01

    Evolutionary game theory is a powerful framework for studying evolution in populations of interacting individuals. A common assumption in evolutionary game theory is that interactions are symmetric, which means that the players are distinguished by only their strategies. In nature, however, the microscopic interactions between players are nearly always asymmetric due to environmental effects, differing baseline characteristics, and other possible sources of heterogeneity. To model these phenomena, we introduce into evolutionary game theory two broad classes of asymmetric interactions: ecological and genotypic. Ecological asymmetry results from variation in the environments of the players, while genotypic asymmetry is a consequence of the players having differing baseline genotypes. We develop a theory of these forms of asymmetry for games in structured populations and use the classical social dilemmas, the Prisoner's Dilemma and the Snowdrift Game, for illustrations. Interestingly, asymmetric games reveal essential differences between models of genetic evolution based on reproduction and models of cultural evolution based on imitation that are not apparent in symmetric games.

  19. Frequency and Effect of Access-Related Vascular Injury and Subsequent Vascular Intervention After Transcatheter Aortic Valve Replacement

    DEFF Research Database (Denmark)

    Dencker, Ditte; Taudorf, Mikkel; Luk, N H Vincent

    2016-01-01

    Vascular access and closure remain a challenge in transcatheter aortic valve replacement (TAVR). This single-center study aimed to report the incidence, predictive factors, and clinical outcomes of access-related vascular injury and subsequent vascular intervention. During a 30-month period, 365...... patients underwent TAVR and 333 patients (94%) were treated by true percutaneous transfemoral approach. Of this latter group, 83 patients (25%) had an access-related vascular injury that was managed by the use of a covered self-expanding stent (n = 49), balloon angioplasty (n = 33), or by surgical...... for access-related vascular intervention. In addition, a high sheath/common femoral artery ratio as measured on preoperative CTA was associated with a higher rate of post-TAVR vascular intervention. The radiation dose, iodine contrast volume, transfusion need, length of hospitalization, and 30-day mortality...

  20. Vascular anomalies

    Directory of Open Access Journals (Sweden)

    Murthy Jyotsna

    2005-01-01

    Full Text Available Management of vascular anomalies is an emerging multidisciplinary, super-specialisation field involving several surgical, medical and radiological specialties. Over the years, development in this field has been limited because of complex nomenclature and lack of consensus on the best practice for treatment of some of the more complex vascular anomalies. It was only in 1996 that the International Society of the Study of Vascular Anomalies defined nomenclature for the anomalies and gave clear guidelines on management, allowing for improved clinical practices. As in all fields of clinical medicine, the correct diagnosis of the vascular anomalies is essential to choose the appropriate treatment. This paper gives clear guidelines for diagnosis, understanding of the anomalies and discusses their management.

  1. Vascular Dementia

    OpenAIRE

    Maria Alekseyevna Cherdak; O V Uspenskaya

    2015-01-01

    This is the author accepted manuscript. The final version is available from Elsevier via http://dx.doi.org/10.1016/S0140-6736(15)00463-8 Vascular dementia is one of the most common causes of dementia after Alzheimer's disease, causing around 15% of cases. However, unlike Alzheimer's disease, there are no licensed treatments for vascular dementia. Progress in the specialty has been difficult because of uncertainties over disease classification and diagnostic criteria, controversy over the e...

  2. Randomised trial of self-expanding metal stents versus polyethylene stents for distal malignant biliary obstruction

    NARCIS (Netherlands)

    Davids, P. H.; Groen, A. K.; Rauws, E. A.; Tytgat, G. N.; Huibregtse, K.

    1992-01-01

    Self-expanding metal stents are claimed to prolong biliary-stent patency, although no formal comparative trial between plastic and expandable stents has been done. In a prospective randomised trial, we assigned 105 patients with irresectable distal bile-duct malignancy to receive either a metal

  3. 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.)

  4. 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.

  5. 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 Metal...

  6. Biolimus-Eluting Stents With Biodegradable Polymer Versus Bare-Metal Stents in Acute Myocardial Infarction

    NARCIS (Netherlands)

    Räber, Lorenz; Kelbaek, Henning; Taniwaki, Masanori; Ostojic, Miodrag C.; Heg, Dik; Baumbach, Andreas; von Birgelen, Clemens; Roffi, Marco; Tüller, David; Engstrøm, Thomas; Moschovitis, Aris; Pedrazzini, Giovanni; Wenaweser, Peter; Kornowski, Ran; Weber, Klaus; Lüscher, Thomas F.; Matter, Christian M.; Meier, Bernard; Jüni, Peter; Windecker, Stephan

    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 Metal

  7. PulmoStent : In Vitro to In Vivo Evaluation of a Tissue Engineered Endobronchial Stent

    NARCIS (Netherlands)

    Thiebes, Anja Lena; Kelly, Nicola; Sweeney, Caoimhe A.; McGrath, Donnacha J.; Clauser, Johanna; Kurtenbach, Kathrin; Gesche, Valentine N.; Chen, Weiluan|info:eu-repo/dai/nl/371747198; Kok, Robbert Jan|info:eu-repo/dai/nl/170678326; Steinseifer, Ulrich; Bruzzi, Mark; O’Brien, Barry J.; McHugh, Peter E.; Jockenhoevel, Stefan; Cornelissen, Christian G.

    Currently, there is no optimal treatment available for end stage tumour patients with airway stenosis. The PulmoStent concept aims on overcoming current hurdles in airway stenting by combining a nitinol stent with a nutrient-permeable membrane, which prevents tumour ingrowth. Respiratory epithelial

  8. Predictors of stent dysfunction after self-expandable metal stent placement for malignant gastric outlet obstruction: tumor ingrowth in uncovered stents and migration of covered stents.

    Science.gov (United States)

    Hori, Yasuki; Naitoh, Itaru; Hayashi, Kazuki; Ban, Tesshin; Natsume, Makoto; Okumura, Fumihiro; Nakazawa, Takahiro; Takada, Hiroki; Hirano, Atsuyuki; Jinno, Naruomi; Togawa, Shozo; Ando, Tomoaki; Kataoka, Hiromi; Joh, Takashi

    2017-10-01

    Endoscopic metallic stenting is widely accepted as a palliation therapy for malignant gastric outlet obstruction (GOO). However, the predictors of stent dysfunction have not been clarified. We aimed to evaluate the predictors, especially tumor ingrowth in uncovered self-expandable metallic stents (U-SEMS) and migration of covered self-expandable metallic stents (C-SEMS), which are the main causes related to the stent characteristics. In this multicenter retrospective study, we compared patients with U-SEMS and C-SEMS in terms of clinical outcomes, and predictors of stent dysfunction. In total, 252 patients (126 with U-SEMS and 126 with C-SEMS) were enrolled. There were no significant differences in technical success, clinical success, GOO score, or time to stent dysfunction. Tumor ingrowth was significantly more frequent in U-SEMS (U-SEMS, 11.90% vs. C-SEMS, 0.79%; p = 0.002), and stent migration was significantly more frequent for C-SEMS (C-SEMS, 8.73% vs. U-SEMS, 0.79%; p = 0.005). Karnofsky performance status (p = 0.04), no presence of ascites (p = 0.02), and insufficient (migration. Both U-SEMS and C-SEMS are effective with comparable patencies. Tumor ingrowth and stent migration are the main causes of stent dysfunction for U-SEMS and C-SEMS, respectively. With regard to stent dysfunction, U-SEMS might be a good option for patients receiving chemotherapy, while C-SEMS with longer stents for patients in good condition. (Clinical trial registration number: UMIN000024059).

  9. Stent tunnel technique to save thrombosed native hemodialysis fistula with extensive venous aneurysm

    Directory of Open Access Journals (Sweden)

    Rabellino M

    2017-07-01

    Full Text Available Martin Rabellino,1 Guillermo J Rosa-Diez,2 Sergio A Shinzato,1 Pablo Rodriguez,1 Oscar A Peralta,1 Maria S Crucelegui,2 Rosario Luxardo,2 Agustina Heredia-Martinez,2 Mariela I Bedini-Rocca,2 Ricardo D García-Mónaco1 1Department of Angiography and Endovascular Therapy, 2Department of Nephrology, Hospital Italiano de Buenos Aires, Buenos Aires, Argentina Introduction and purpose: The increasing number of patients undergoing hemodialysis and the limited number of access sites have resulted in an increasing number of techniques to maintain vascular access for hemodialysis. Thrombosed arteriovenous (AV fistulas with large venous aneurysms have poor treatment results, with both endovascular and surgical techniques, leading to a high rate of definitive AV access loss. The purpose of this study was to review the feasibility and initial results of this novel endovascular treatment of thrombosed AV fistulas with large venous aneurysms.Materials and methods: A novel endovascular treatment technique of inserting nitinol auto-expandable uncovered stents stretching through the whole puncture site area, thus creating a tunnel inside the thrombus, was retrospectively analyzed and described.Results: A total of 17 stents were placed in 10 hemodialysis fistulas, with a mean venous coverage length of 17.8 cm. In all the cases, 100% technical success was achieved, with complete restoration of blood flow in all patients. There were no procedure-related complications. The mean follow-up was 167 days (range 60–420 days, with a primary and assisted patency of 80% and 100%, respectively. No multiple trans-stent struts-related complications were observed. Three stent fractures were diagnosed with plain films at the site of puncture without consequence in the venous access permeability.Conclusion: The “stent tunnel technique” is a feasible, safe and effective alternative to salvage native hemodialysis access, thus extending the function of the venous access with

  10. Endovascular Management of Vascular Injury during Transsphenoidal Surgery.

    Science.gov (United States)

    Cinar, C; Bozkaya, H; Parildar, M; Oran, I

    2013-03-01

    Vascular injury is an unusual and serious complication of transsphenoidal surgery. We aimed to define the role of angiography and endovascular treatment in patients with vascular injuries occurring during transsphenoidal surgery. During the last ten-year period, we retrospectively evaluated nine patients with vascular injury after transsphenoidal surgery. Eight patients were symptomatic due to vascular injury, while one had only suspicion of vascular injury during surgery. Four patients presented with epistaxis, two with subarachnoid hemorrhage, one with exophthalmos, and one with hemiparesia. Emergency angiography revealed a pseudoaneurysm in four patients, contrast extravasation in two, vessel dissection in one, vessel wall irregularity in one, and arteriovenous fistula in one. All patients but one were treated successfully with parent artery occlusion, with one covered stent implantation, one stent-assisted coiling method, while one patient was managed conservatively. One patient died due to complications related to the primary insult without rebleeding. Vascular injuries suspected intra or postoperatively must be investigated rapidly after transsphenoidal surgery. Endovascular treatment with parent artery occlusion is feasible with acceptable morbidity and mortality rates in the treatment of vascular injuries occurring in transsphenoidal surgery.

  11. Covered stent implantation through a single 8-french guide catheter for the management of a distal coronary perforation.

    Science.gov (United States)

    Sandoval, Yader; Lobo, Angie S; Brilakis, Emmanouil S

    2017-10-01

    Distal coronary perforation can cause early or late tamponade and is usually treated with fat or coil embolization. An alternative treatment strategy is occlusion of the ostium of the perforated vessel via implantation of a covered stent in the main vessel, which is typically achieved using the ping-pong guide catheter technique. In this technique, a balloon is inflated over one guide catheter to stop pericardial bleeding and a covered stent is delivered through a second guide catheter due to inability to fit both a balloon and a covered stent through a single guide catheter. With development of lower profile rapid exchange covered stents, a single guide catheter can be used to both occlude the target vessel and deliver the covered stent. We describe a case of distal vessel perforation in which a balloon was inflated to stop pericardial bleeding, followed by delivery of a covered stent (Graftmaster, Abbott Vascular) through a single 8-Fr guide catheter. This "block and deliver" technique represents a novel paradigm for treating coronary perforations through a single guide catheter, obviating the need for the ping-pong guide catheter technique. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  12. Flow-diverting Stent in the Treatment of Cervical Carotid Dissection and Pseudoaneurysm: Review of Literature and Case Report.

    Science.gov (United States)

    Baptista-Sincos, Anna Paula Weinhardt; Simplício, Aline Bigatão; Sincos, Igor Rafael; Leaderman, Alex; Neto, Fernando Saliture; Moraes, Adjaldes; Aun, Ricardo

    2018-01-01

    The endovascular technique has been recommended over the past few years to extracranial carotid dissection and pseudoaneurysm with promising results, especially after medical therapy failure. Flow-diverting stents are an alternative for complex cases. These stents have proven to be effective treatment devices for intracranial aneurysms. The reference list of Pham's systematic review, published in 2011, and Seward's literature review, published in 2015, was considered, as well as all new articles with eligible features. Search was conducted on specific databases: MEDLINE and Literatura Latino-Americana e do Caribe em Ciências da Saúde. For carotid dissection and pseudoaneurysm, our review yielded 3 published articles including 12 patients. The technical success rate of flow-diverting stent was 100% with no procedural complication described. Mean clinical follow-up was 27.2 months (range 5-48), and in 5 months' angiographic follow-up, all lesions had healed. No new neurological events were reported during the clinical follow-up. Flow diverter stent use on intracranial and peripheral vascular surgery demonstrates satisfactory initial results, but it is still under investigation. There are very few cases treated till now and the initial results with flow-diverting stents to cervical carotid dissection are promising. In well-selected cases, where simple embolization or conventional stent is not appropriate, this technic may be considered. Copyright © 2017 Elsevier Inc. All rights reserved.

  13. Comparison of two endovascular treatments of a stenosed arteriovenous fistula: balloon-angioplasty with and without stenting.

    Science.gov (United States)

    Decorato, Iolanda; Kharboutly, Zaher; Legallais, Cécile; Salsac, Anne-Virginie

    2014-10-01

    Arteriovenous fistulas (AVFs) are created in patients to enable a permanent vascular access for hemodialysis. The AVF causes changes in the hemodynamic conditions leading to possible complications, stenoses being the most common one. Our objective was to compare the effect of treating the stenosed AVF by balloon-angioplasty, whether followed or not with stenting. We considered an AVF presenting an 60% arterial stenosis and simulated the two endovascular treatments using an implicit approach. We then simulated the fluid-structure interactions (FSI) within (i) the patient-specific stenosed AVF, (ii) the AVF after angioplasty, and (iii) the AVF after angioplasty plus stenting with ANSYS Workbench. We show that a self-expandable stent does not modify the curvature of the vessel after angioplasty; it only increases the local Young modulus of the stented wall by an order of magnitude. The results of the FSI simulations indicate that the two treatments induce the same hemodynamic conditions: they both reduce the pressure difference across the stenosis, while maintaining the flow distribution downstream of the stenosis. The venous flow rate that has to be guaranteed for hemodialysis is unaltered. Thanks to its large axial flexibility, the self-expandable stent causes at maximum a three-fold increase in the internal wall stresses at peak systole as compared to angioplasty alone. By maintaining the vessel lumen shape over time, the stent is likely to reduce the risk of restenosis that can otherwise occur after balloon-angioplasty because of the viscoelastic recoil of the vessel.

  14. Vascular Access Procedures

    Science.gov (United States)

    ... News Physician Resources Professions Site Index A-Z Vascular Access Procedures A vascular access procedure inserts a flexible, ... the limitations of Vascular Access Procedures? What are Vascular Access Procedures? A vascular access procedure involves the insertion ...

  15. Vascular Access for Hemodialysis

    Science.gov (United States)

    ... Adequacy Eating & Nutrition for Hemodialysis Vascular Access for Hemodialysis What is a vascular access? A vascular access ... Set Up the Vascular Access Well before Starting Hemodialysis Patients should set up a vascular access well ...

  16. What Is Vascular Disease?

    Science.gov (United States)

    ... Policy What Is Vascular Disease? What Is Vascular Disease? Vascular disease is any abnormal condition of the blood ... Privacy Policy × Your ticket for the: What Is Vascular Disease? Title What Is Vascular Disease? USD Close Print

  17. Asymmetric fluorocyclizations of alkenes.

    Science.gov (United States)

    Wolstenhulme, Jamie R; Gouverneur, Véronique

    2014-12-16

    CONSPECTUS: The vicinal fluorofunctionalization of alkenes is an attractive transformation that converts feedstock olefins into valuable cyclic fluorinated molecules for application in the pharmaceutical, agrochemical, medical, and material sectors. The challenges associated with asymmetric fluorocyclizations induced by F(+) reagents are distinct from other types of halocyclizations. Processes initiated by the addition of an F(+) reagent onto an alkene do not involve the reversible formation of bridged fluoronium ions but generate acyclic β-fluorocationic intermediates. This mechanistic feature implies that fluorocyclizations are not stereospecific. A discontinuity exists between the importance of this class of fluorocyclization and the activation modes currently available to implement successful catalysis. Progress toward fluorocyclization has been achieved by investing in neutral and cationic [NF] reagent development. The body of work on asymmetric fluorination using chiral cationic [NF](+) reagents prepared by fluorine transfer from the dicationic [NF](2+) reagent Selectfluor to quinuclidines, inspired the development of asymmetric F(+)-induced fluorocyclizations catalyzed by cinchona alkaloids; for catalysis, the use of N-fluorobenzenesulfonimide, which is less reactive than Selectfluor, ensures that the achiral F(+) source remains unreactive toward the alkene. These organocatalyzed enantioselective fluorocyclizations can be applied to indoles to install the fluorine on a quaternary benzylic stereogenic carbon center and to afford fluorinated analogues of natural products featuring the hexahydropyrrolo[2,3-b]indole or the tetrahydro-2H-furo[2,3-b]indole skeleton. In an alternative approach, the poor solubility of dicationic Selectfluor bis(tetrafluoroborate) in nonpolar solvent was exploited with anionic phase transfer catalysis as the operating activation mode. Exchange of the tetrafluoroborate ions of Selectfluor with bulky lipophilic chiral anions (e

  18. A Randomized Comparison between Everolimus-Eluting Stent and Cobalt Chromium Stent in Patients with Acute ST-Elevation Myocardial Infarction Undergoing Primary Percutaneous Coronary Intervention Using Routine Intravenous Eptifibatide: The X-MAN (Xience vs. Multi-Link Stent in Acute Myocardial Infarction) Trial, A Pilot Study.

    Science.gov (United States)

    Dharma, Surya; Wardeh, Alexander J; Soerianata, Sunarya; Firdaus, Isman; Jukema, J Wouter

    2014-06-01

    The objective of this study is to determine the efficacy and safety of an everolimus-eluting stent (EES/Xience; Abbott Vascular, Santa Clara, CA) compared with a cobalt chromium stent (CoCr/Multi-Link Vision; Abbott Vascular) in patients with acute ST-elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (PCI) with routine administration of eptifibatide infusion. This is a prospective, single center, randomized trial comparing EES (n = 75) and CoCr stent (n = 75) implantation in patients with acute STEMI undergoing primary PCI. Intravenous eptifibatide administration was mandatory by protocol in this pilot study. The primary efficacy endpoint was major adverse cardiac events (MACE) at 30 days, defined as the composite of death, reinfarction, and target vessel revascularization. Secondary safety endpoints were stent thrombosis at 30 days and in-hospital bleeding event. Acute reperfusion parameters were also assessed. One-month MACE rate did not differ between EES and CoCr group (1.3 vs. 1.3%, p = 1.0). No stent thrombosis cases were observed in the EES group. The groups did not differ with respect to in-hospital bleeding events (5 vs. 9%, p = 0.37), achievement of final thrombolysis in myocardial infarction flow 2 or 3 (p = 0.21), achievement of myocardial blush grade 2 or 3 (p = 0.45), creatine kinase-MB level at 8 to 12 hours after stenting (p = 0.29), and left ventricular ejection fraction (p = 0.21). This pilot study demonstrates that after one-month follow-up, the use of EES is as safe and effective as the use of CoCr stents in patients with acute STEMI undergoing primary PCI with routine administration of intravenous eptifibatide.

  19. Catalytic asymmetric fluorinations.

    Science.gov (United States)

    Bobbio, Carla; Gouverneur, Véronique

    2006-06-07

    The appearance of structurally diverse fluorinating reagents displaying a large spectrum of reactivity has been critical to the development of the catalytic asymmetric fluorination processes known to date. In this article, we discuss how this area of research emerged and which strategies have allowed for the successful development of both nucleophilic and electrophilic catalytic enantioselective fluorinations. We also present the fundamental understanding of catalytic activity and enantioselectivity for the most efficient processes and highlight the first synthetic application with the preparation of a complex fluorinated target.

  20. Asymmetric synthesis v.4

    CERN Document Server

    Morrison, James

    1984-01-01

    Asymmetric Synthesis, Volume 4: The Chiral Carbon Pool and Chiral Sulfur, Nitrogen, Phosphorus, and Silicon Centers describes the practical methods of obtaining chiral fragments. Divided into five chapters, this book specifically examines initial chiral transmission and extension. The opening chapter describes the so-called chiral carbon pool, the readily available chiral carbon fragments used as building blocks in synthesis. This chapter also provides a list of 375 chiral building blocks, along with their commercial sources, approximate prices, and methods of synthesis. Schemes involving

  1. Asymmetric Organocatalytic Cycloadditions

    DEFF Research Database (Denmark)

    Mose, Rasmus

    2016-01-01

    were pioneered by Otto Paul Hermann Diels and Kurt Alder who discovered what later became known as the Diels Alder reaction. The Diels Alder reaction is a [4+2] cycloaddition in which a π4 component reacts with a π2 component via a cyclic transition state to generate a 6 membered ring. This reaction...... undergo cascade reactions with different electron deficient dienophiles in Diels Alder – nucleophilic ring closing reactions. This methodology opens up for the direct asymmetric formation of hydroisochromenes and hydroisoquinolines which may possess interesting biological activities. It is also...

  2. Comparison of uncovered stent with covered stent for treatment of malignant colorectal obstruction.

    Science.gov (United States)

    Lee, Kee Myung; Shin, Sung Jae; Hwang, Jae Chul; Cheong, Jae Youn; Yoo, Byung Moo; Lee, Kwang Jae; Hahm, Ki Baik; Kim, Jin Hong; Cho, Sung Won

    2007-11-01

    Insertion of self-expandable metallic stents (SEMS) can provide rapid relief of malignant colorectal obstruction and can be used as a palliative treatment or as a bridge to surgery. A SEMS can be classified as an uncovered or covered stent. Both types of stents have their own merits and demerits. The objectives of this study were to compare success rates, durability, and complication rates of uncovered and covered stent groups of malignant colorectal obstruction. DESIGNS AND SETTING: A nonrandomized prospective, single-center study. We studied 80 patients with malignant colorectal obstruction: colon cancer in 70 patients, metastatic lesion of advanced gastric cancer in 8 patients, and cervix cancer in 2 patients. Insertion of uncovered stents was attempted in 39 patients (before surgery in 20, palliative in 19), and covered stents were used in 41 (before surgery in 23, palliative in 18). The stent was inserted into the obstructive sites for preoperative or palliative purposes by using the through-the-scope method. After stent insertion, the patients had regular follow-ups, either as clinical checkups or telephone interviews. Insertion success rate, durability, and complication rate according to stent type. Technical and clinical success rates of uncovered and covered stents were not different (100%; 95.1%, P > .05, 100%; 97.4%, P > .05). The early stent migration rate was not different in both groups. The late stent migration was more common in the covered stent group than the uncovered stent group (0% vs 40%, respectively, P = .005). Loss of stent function during the long-term follow-up period was more frequent in the covered stent group than in the uncovered stent group (18.8% vs 60%, respectively, P = .018). This was a small-sized, nonrandomized, prospective, single-center study. Confirmation of large-scale, multicenter, randomized, prospective outcome is required. Insertion of either an uncovered or covered stent is similarly an effective treatment modality of

  3. Carotid Endarterectomy and Carotid Artery Stenting in the US Medicare Population, 1999-2014.

    Science.gov (United States)

    Lichtman, Judith H; Jones, Michael R; Leifheit, Erica C; Sheffet, Alice J; Howard, George; Lal, Brajesh K; Howard, Virginia J; Wang, Yun; Curtis, Jeptha; Brott, Thomas G

    2017-09-19

    .6% [95% CI, 1.2% to 2.1%]; adjusted annual decrease, 1.86% [95% CI, 1.45%-2.26%]). Additional improvements were noted for in-hospital mortality, 30-day stroke, myocardial infarction, or death, and 30-day all-cause mortality as well as within demographic subgroups. Among fee-for-service Medicare beneficiaries, the performance of carotid endarterectomy declined from 1999 to 2014, whereas the performance of carotid artery stenting increased until 2006 and then declined from 2007 to 2014. Outcomes improved despite increases in vascular risk factors.

  4. 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 differe...... or experienced microsurgeons regardless of their clinical experience. The study also shows that some surgical experience seems to be an advantage in performing microsurgery....

  5. Stenting of bifurcation lesions: a rational approach.

    Science.gov (United States)

    Lefèvre, T; Louvard, Y; Morice, M C; Loubeyre, C; Piéchaud, J F; Dumas, P

    2001-12-01

    The occurrence of stenosis in or next to coronary bifurcations is relatively frequent and generally underestimated. In our experience, such lesions account for 15%-18% of all percutaneous coronary intervention > (PCI). The main reasons for this are (1) the coronary arteries are like the branches of a tree with many ramifications and (2) because of axial plaque redistribution, especially after stent implantation, PCI of lesions located next to a coronary bifurcation almost inevitably cause plaque shifting in the side branches. PCI treatment of coronary bifurcation lesions remains challenging. Balloon dilatation treatment used to be associated with less than satisfactory immediate results, a high complication rate, and an unacceptable restenosis rate. The kissing balloon technique resulted in improved, though suboptimal, outcomes. Several approaches were then suggested, like rotative or directional atherectomy, but these techniques did not translate into significantly enhanced results. With the advent of second generation stents, in 1996, the authors decided to set up an observational study on coronary bifurcation stenting combined with a bench test of the various stents available. Over the last 5 years, techniques, strategies, and stent design have improved. As a result, the authors have been able to define a rational approach to coronary bifurcation stenting. This bench study analyzed the behavior of stents and allowed stents to be discarded that are not compatible with the treatment of coronary bifurcations. Most importantly, this study revealed that stent deformation due to the opening of a strut is a constant phenomenon that must be corrected by kissing balloon inflation. Moreover, it was observed that the opening of a stent strut into a side branch could permit the stenting, at least partly, of the side branch ostium. This resulted in the provocative concept of "stenting both branches with a single stent." Therefore, a simple approach is currently implemented

  6. [Influence of curcumin--loaded poly (lactide-co-glycolide) films on the proliferation of vascular smooth muscle cells].

    Science.gov (United States)

    Ren, Ling; Wang, Jin; Tang, Jiaju; Pan, Changjiang; Huang, Nan

    2008-08-01

    In-stent restenosis is the major problem of percutaneous coronary interventions. Drug-eluting stent became a landmark in the treatment of coronary disease. Curcumin could be used for drug-eluting stent due to its antithrombogenity and antiproliferative properties. In this paper, 3-(4, 5-Dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assays were performed to decide the optimal concentration of curcumin for inhibiting the proliferation of vascular smooth muscle cells (VSMC). The result disclosed that more than 80% of VSMC were inhibited when the concentration of curcumin ranged from 2.5 microg/ml to 10 microg/ml (P cells. The results of Alamar Blue test indicated that the curcumin-loaded films had better antiproliferation effect than did the 316 stainless steel (SS). Therefore, these films may be used for stent coating to inhibit the in-stent restenosis induced by VSMC proliferation.

  7. LVIS Stent Versus Enterprise Stent for the Treatment of Unruptured Intracranial Aneurysms.

    Science.gov (United States)

    Ge, Huijian; Lv, Xianli; Yang, Xinjian; He, Hongwei; Jin, Hengwei; Li, Youxiang

    2016-07-01

    This retrospective study compared clinical and angiographic outcomes between LVIS and Enterprise stents. From November 2014 to December 2015, total 190 patients with 208 unruptured intracranial aneurysms were coiled assisted by LVIS and Enterprise stents. Procedure-related complications, clinical outcomes, and angiographic results were analyzed retrospectively. A total of 92 patients with 96 aneurysms received LVIS stents and 98 patients with 112 aneurysms were treated with Enterprise stents. Procedure-related complications occurred in 10.9% of patients (2 hemorrhagic events and 8 thromboembolic events) in the LVIS stents group whereas 16.3% (1 hemorrhage, 1 mass effect, and 14 thromboembolic events) in the Enterprise stents group. No statistical significant differences in thromboembolic (P = 0.263), hemorrhagic complications (P = 0.611), and favorable clinical outcomes (modified Rankin Scores of 0-2) (P = 0.379) were found between 2 groups. A greater initial complete or near-complete obliteration was found in the LVIS stents group compared with the Enterprise stents group (96.9% vs. 88.4%, P = 0.034). Larger aneurysm size (P = 0.048) was an independent predictor of procedure-related complications in univariate analysis. Compared with Enterprise stents, LVIS stents may achieve greater complete or near-complete occlusion rate. There was no significant difference in procedural-related complications and clinical outcomes between LVIS and Enterprise stents. Copyright © 2016 Elsevier Inc. All rights reserved.

  8. Levels of circulating CD34+/KDR+ cells do not predict coronary in-stent restenosis.

    Science.gov (United States)

    Haine, Steven E; Van Craenenbroeck, Emeline M; Hoymans, Vicky Y; Miljoen, Hielko P; Vandendriessche, Tom R; Claeys, Marc J; Frederix, Geert; Conraads, Viviane M; Bosmans, Johan M; Vrints, Christiaan J

    2014-01-01

    Angiographic and clinical parameters are poor predictors of in-stent restenosis. Bone marrow-derived CD34(+) cells that coexpress a receptor for vascular endothelial growth factor (kinase insert domain receptor [KDR]) are committed to endothelial lineage. Mobilization and infusion of CD34(+)/KDR(+) cells accelerates re-endothelialization and reduces neointimal thickness in vascular injury models. Bioengineered stents capturing CD34(+) cells also show expedited re-endothelialization. We examined whether circulating CD34(+)/KDR(+) cell counts can be used to predict restenosis in a bare-metal stent (BMS). CD34(+)/KDR(+) cells were counted by flow cytometry in 124 nondiabetic patients before BMS implantation and the relation to in-stent late luminal loss (LLL) was examined by angiography at 6 months (primary end point). Neointima was also quantified as the maximum percentage area stenosis (M%AS) and percentage volume intima hyperplasia (%VIH) on intravascular ultrasonography (secondary end points). Multiple linear regression analysis, taking into account implanted stent length and diameter, revealed no relation between CD34(+)/KDR(+) cell counts and LLL (partial regression coefficient b = 0.11; 95% confidence interval [CI], -0.19-0.42; P = 0.46). Similarly, no relation between CD34(+)/KDR(+) cell counts and M%AS or %VIH could be demonstrated. Moreover, the increase in CD34(+)/KDR(+) cell counts over 6 months was unrelated to LLL (b = -0.15; 95% CI, -0.42-0.12; P = 0.28), M%AS, and %VIH. Although our study does not exclude a pathophysiologic role for CD34(+)/KDR(+) cells in the formation of neointima, cell counts before percutaneous coronary intervention proved to be unrelated to LLL or intravascular ultrasonographically derived restenosis parameters in coronary BMSs at 6 months. Copyright © 2014 Canadian Cardiovascular Society. Published by Elsevier Inc. All rights reserved.

  9. Process mapping of PTA and stent placement in a university hospital interventional radiology department.

    Science.gov (United States)

    de Bucourt, Maximilian; Busse, Reinhard; Güttler, Felix; Reinhold, Thomas; Vollnberg, Bernd; Kentenich, Max; Hamm, Bernd; Teichgräber, Ulf K

    2012-08-01

    To apply the process mapping technique in an interdisciplinary approach in order to visualize, better understand, and efficiently organize percutaneous transluminal angioplasty (PTA) and stent placement procedures in a university hospital's interventional radiology department. After providing an overview of seven established mapping techniques for medical professionals, the process mapping technique was chosen and applied in an interdisciplinary approach including referrers (physicians, nurses, and other staff in referring departments, e.g., vascular surgery), providers (interventional radiologists, nurses, technicians, and staff of the angiography suite), and specialists of the hospital's controlling department. A generally binding and standardized process map was created, describing the entire procedure for a patient in whom the radiological intervention of PTA or stent treatment is contemplated from admission to the department of vascular surgery until discharge after successful treatment. This visualization tool assists in better understanding (especially given natural staff fluctuation over time) and efficiently organizing PTA and stent procedures. Process mapping can be applied for streamlining workflow in healthcare, especially in interdisciplinary settings. By defining exactly what a business entity does, who is responsible, to what standard a process should be completed, and how the success can be assessed, this technique can be used to eliminate waste and inefficiencies from the workplace while providing high-quality goods and services easily, quickly, and inexpensively. Process mapping can be used in a university hospital's interventional radiology department. • Process mapping can describe the patient's entire process from admission to PTA/stent placement until discharge. • Process mapping can be used in interdisciplinary teams (e.g., referrers, providers, and controlling specialists). • Process mapping can be used in order to more efficiently

  10. Vascular dementia.

    Science.gov (United States)

    O'Brien, John T; Thomas, Alan

    2015-10-24

    Vascular dementia is one of the most common causes of dementia after Alzheimer's disease, causing around 15% of cases. However, unlike Alzheimer's disease, there are no licensed treatments for vascular dementia. Progress in the specialty has been difficult because of uncertainties over disease classification and diagnostic criteria, controversy over the exact nature of the relation between cerebrovascular pathology and cognitive impairment, and the paucity of identifiable tractable treatment targets. Although there is an established relation between vascular and degenerative Alzheimer's pathology, the mechanistic link between the two has not yet been identified. This Series paper critiques some of the key areas and controversies, summarises treatment trials so far, and makes suggestions for what progress is needed to advance our understanding of pathogenesis and thus maximise opportunities for the search for new and effective management approaches. Copyright © 2015 Elsevier Ltd. All rights reserved.

  11. [Vascular trauma].

    Science.gov (United States)

    Furuya, T; Nobori, M; Tanaka, N

    1999-07-01

    Vascular trauma is essentially acute arterial obstruction, often combined with hemorrhage, fracture, and infection. It can be both life-threatening and limb-threatening and needs an emergency operation. In vascular trauma patient, multiple fracture and organ injury, such as brain, lung, liver, spleen, kidney, or gastrointestinal tract should be evaluated to decide treatment priority. When the pulse distal from the injured site is absent or diminished, vascular trauma is most likely and reconstruction should be accomplished within "the golden time (6-8 hours)". Intimal damage followed by platelet aggregation and thrombus formation will necessitate resection and repair of the site instead of simple thrombectomy. Although autogenous vein is the first choice, artificial graft can be implanted for short segment in non-infected field.

  12. Very Late Stent Thrombosis 42 Months after Implantation of Sirolimus-Eluting Stent and Discontinuation of Antiplatelet Therapy

    Directory of Open Access Journals (Sweden)

    Dirk Sibbing

    2009-01-01

    Full Text Available Although safety profiles of sirolimus-eluting stents do not seem to differ in short-to-medium term from those of bare-metal stents, late stent thrombosis after deployment of drug-eluting stents has emerged as a potential safety concern in the era of high-pressure stent implantation. Here, we describe the case of a patient with acute myocardial infarction due to stent thrombosis of a sirolimus-eluting stent 42 months after stent deployment and 5 weeks after discontinuation of aspirin treatment. To the best of our knowledge, this is one of the most delayed cases of sirolimus-eluting stent thrombosis described so far. The case emphasizes the potential risk that late stent thrombosis can unpredictably occur at any time point after drug-eluting stent deployment.

  13. Asymmetric inclusion process.

    Science.gov (United States)

    Reuveni, Shlomi; Eliazar, Iddo; Yechiali, Uri

    2011-10-01

    We introduce and explore the asymmetric inclusion process (ASIP), an exactly solvable bosonic counterpart of the fermionic asymmetric exclusion process (ASEP). In both processes, random events cause particles to propagate unidirectionally along a one-dimensional lattice of n sites. In the ASEP, particles are subject to exclusion interactions, whereas in the ASIP, particles are subject to inclusion interactions that coalesce them into inseparable clusters. We study the dynamics of the ASIP, derive evolution equations for the mean and probability generating function (PGF) of the sites' occupancy vector, obtain explicit results for the above mean at steady state, and describe an iterative scheme for the computation of the PGF at steady state. We further obtain explicit results for the load distribution in steady state, with the load being the total number of particles present in all lattice sites. Finally, we address the problem of load optimization, and solve it under various criteria. The ASIP model establishes bridges between statistical physics and queueing theory as it represents a tandem array of queueing systems with (unlimited) batch service, and a tandem array of growth-collapse processes.

  14. 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.

  15. Three-year results of the VIBRANT trial of VIABAHN endoprosthesis versus bare nitinol stent implantation for complex superficial femoral artery occlusive disease.

    Science.gov (United States)

    Geraghty, Patrick J; Mewissen, Mark W; Jaff, Michael R; Ansel, Gary M

    2013-08-01

    complex superficial femoral artery disease intervention using the VIABAHN endograft and bare nitinol stents are similar. Although primary patency rates are low in both study arms, excellent primary-assisted and secondary patency rates were achieved, with sustained augmentation of limb perfusion and quality-of-life measures. Patency rates diminish most rapidly in the first year after device implantation. Copyright © 2013 Society for Vascular Surgery. Published by Mosby, Inc. All rights reserved.

  16. Clinical Implications of Stent Culture in Patients with Indwelling Ureteral Stents Prior to Ureteroscopy.

    Science.gov (United States)

    Nevo, Amihay; Mano, Roy; Schreter, Eran; Lifshitz, David A

    2017-07-01

    We determined the ability of urine culture to predict stent culture status and associated infectious pathogens, and evaluated the association between stent culture and post-ureteroscopy sepsis. We queried the prospectively collected database at our institution and identified all patients who underwent ureteroscopy between October 2010 and August 2016 who had a ureteral stent before the operation and from whom urine and stent cultures were obtained. The study end point was post-ureteroscopy sepsis within 48 hours of the procedure. We compared urine and stent culture findings, and performed univariate and multivariate analyses to identify predictors of post-ureteroscopy sepsis. The study group comprised 509 patients with a median age of 56 years, of whom 147 (28.9%) were female. Positive urine cultures were found in 91 patients (17.8%) and positive stent cultures were found in 104 (20.4%). Urine and stent cultures were positive in 48 patients (9.4%), of whom only 24 had identical bacteria in both cultures. The most common pathogens isolated from urine and stent cultures were Escherichia coli in 38.5% and Enterococcus in 18.4%. Sepsis developed in 25 patients (4.9%), including 21 (84%) with a positive stent culture and 14 (59%) with a positive urine culture. On multivariate analysis female gender and positive stent culture were significantly associated with post-ureteroscopy sepsis. Only half of the patients with ureteral stents prior to ureteroscopy, and positive stent and urine cultures had similar pathogens in both cultures. Female gender and positive stent culture were associated with a higher risk of post-ureteroscopy sepsis in this population. Stent culture may direct the proper antibiotic treatment in patients with sepsis after ureteroscopy. Copyright © 2017 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.

  17. Impact of stent platform on longitudinal stent deformation: an in vivo frequency domain optical coherence tomography study.

    Science.gov (United States)

    Yamada, Ryotaro; Okura, Hiroyuki; Kume, Teruyoshi; Fukuhara, Kenzo; Koyama, Terumasa; Higa, Tomitaka; Neishi, Yoji; Yoshida, Kiyoshi; Uemura, Shiro

    2017-07-01

    Recently, longitudinal coronary stent deformation has been highlighted as a possible cause of drug-eluting stent failure. Although bench tests and in vivo studies have demonstrated difference in longitudinal stent strength among the stents with different platforms, its clinical impact is still unknown. Furthermore, it is unknown if modified stent platform favorably affect the incidence of stent deformation. The aim of this study was to investigate the longitudinal deformation of the everolimus-eluting stents (EES) with different stent platforms by using frequency domain optical coherence tomography (FD-OCT). Seventy-eight lesions treated with EES (Xience Prime: n = 26, Promus element: n = 29, Promus premier: n = 23) were studied. After successful stent implantation, FD-OCT was performed and stent length was measured using three-dimensional reconstruction of the images in vivo. Percent longitudinal stent shortening (%SS) was defined as the in vivo stent length divided by nominal stent length. Longitudinal stent deformation was defined as  %SS > 10 %. Patients' and procedural characteristics were similar among 3 EESs. There was no difference in mean  %SS between Xience Prime, Promus Element and Promus Premier (1.0 ± 5.8, 2.9 ± 6.7 and 0.8 ± 3.7 %, p = 0.322). Incidence of the longitudinal stent deformation was significantly higher in Promus Element than the other stents (0, 13.8 and 0 %, p = 0.028). Incidence of longitudinal stent deformation was different between EESs with different stent platforms. Stent material, stent design and/or stent delivery balloon may affect longitudinal stent deformation.

  18. Bare metal stents, durable polymer drug eluting stents, and biodegradable polymer drug eluting stents for coronary artery disease: mixed treatment comparison meta-analysis.

    Science.gov (United States)

    Bangalore, Sripal; Toklu, Bora; Amoroso, Nicholas; Fusaro, Mario; Kumar, Sunil; Hannan, Edward L; Faxon, David P; Feit, Frederick

    2013-11-08

    To compare the efficacy and safety of biodegradable polymer drug eluting stents with those of bare metal stents and durable polymer drug eluting stents. Mixed treatment comparison meta-analysis of 258,544 patient years of follow-up from randomized trials. PubMed, Embase, and Central were searched for randomized trials comparing any of the Food and Drug Administration approved durable polymer drug eluting stents (sirolimus eluting, paclitaxel eluting, cobalt chromium everolimus eluting, platinum chromium everolimus eluting, zotarolimus eluting-Endeavor, and zotarolimus eluting-Resolute) or biodegradable polymer drug eluting stents, with each other or against bare metal stents. Long term efficacy (target vessel revascularization, target lesion revascularization) and safety (death, myocardial infarction, stent thrombosis). Landmark analysis at more than one year was evaluated to assess the potential late benefit of biodegradable polymer drug eluting stents. From 126 randomized trials and 258,544 patient years of follow-up, for long term efficacy (target vessel revascularization), biodegradable polymer drug eluting stents were superior to paclitaxel eluting stents (rate ratio 0.66, 95% credibility interval 0.57 to 0.78) and zotarolimus eluting stent-Endeavor (0.69, 0.56 to 0.84) but not to newer generation durable polymer drug eluting stents (for example: 1.03, 0.89 to 1.21 versus cobalt chromium everolimus eluting stents). Similarly, biodegradable polymer drug eluting stents were superior to paclitaxel eluting stents (rate ratio 0.61, 0.37 to 0.89) but inferior to cobalt chromium everolimus eluting stents (2.04, 1.27 to 3.35) for long term safety (definite stent thrombosis). In the landmark analysis after one year, biodegradable polymer drug eluting stents were superior to sirolimus eluting stents for definite stent thrombosis (rate ratio 0.29, 0.10 to 0.82) but were associated with increased mortality compared with cobalt chromium everolimus eluting stents (1.52, 1

  19. 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

  20. Stent development and local drug delivery

    NARCIS (Netherlands)

    E.S. Regar (Eveline); G. Sianos (Georgios); P.W.J.C. Serruys (Patrick)

    2001-01-01

    textabstractStent implantation has become the new standard angioplasty procedure. Instent re-stenosis remains the major limitation of coronary stenting. Re-stenosis is related to patient-, lesion- and procedure-specific factors. Patient-specific factors can not be influenced to any extent.

  1. Incidence of definite stent thrombosis or in-stent restenosis after drug-eluting stent implantation for treatment of coronary in-stent restenosis. From western denmark heart registry

    DEFF Research Database (Denmark)

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

    2012-01-01

    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...

  2. 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. Copyright © 2011 Wiley Periodicals, Inc.

  3. Symmetric Decomposition of Asymmetric Games.

    Science.gov (United States)

    Tuyls, Karl; Pérolat, Julien; Lanctot, Marc; Ostrovski, Georg; Savani, Rahul; Leibo, Joel Z; Ord, Toby; Graepel, Thore; Legg, Shane

    2018-01-17

    We introduce new theoretical insights into two-population asymmetric games allowing for an elegant symmetric decomposition into two single population symmetric games. Specifically, we show how an asymmetric bimatrix game (A,B) can be decomposed into its symmetric counterparts by envisioning and investigating the payoff tables (A and B) that constitute the asymmetric game, as two independent, single population, symmetric games. We reveal several surprising formal relationships between an asymmetric two-population game and its symmetric single population counterparts, which facilitate a convenient analysis of the original asymmetric game due to the dimensionality reduction of the decomposition. The main finding reveals that if (x,y) is a Nash equilibrium of an asymmetric game (A,B), this implies that y is a Nash equilibrium of the symmetric counterpart game determined by payoff table A, and x is a Nash equilibrium of the symmetric counterpart game determined by payoff table B. Also the reverse holds and combinations of Nash equilibria of the counterpart games form Nash equilibria of the asymmetric game. We illustrate how these formal relationships aid in identifying and analysing the Nash structure of asymmetric games, by examining the evolutionary dynamics of the simpler counterpart games in several canonical examples.

  4. Using the Barrel Technique with the LVIS Jr (Low-profile Visualized Intraluminal Support) Stent to Treat a Wide Neck MCA Bifurcation Aneurysm.

    Science.gov (United States)

    Darflinger, Robert J; Chao, Kuo

    2015-07-01

    The treatment of wide-neck bifurcation cerebral aneurysms is challenging especially if at least one of the arteries arise from an obtuse angle. These wide-neck bifurcation aneurysms are difficult to treat with the usual balloon and stent assisted coiling, including Y stenting or double-barrel stent techniques [1, 2]. Other available options include using current devices with the waffle cone or double waffle cone techniques [3, 4]. Novel devices that are in development include intrasaccular devices and the barrel bifurcation vascular reconstruction device (Covidien) [5, 6, 7]. We report the use of a novel barrel technique using the LVIS (low-profile visualized intraluminal support) Jr stent for the treatment of a wide-neck bifurcation aneurysm.

  5. VASCULAR SURGERY

    African Journals Online (AJOL)

    Venous thromboembolism (VTE) is a complex and serious condition encompassing deep vein thrombosis (DVT) and pulmonary embolism (PE), usually in the lower extremities.1,2. Thromboses can result from venous stasis, vascular injury or hypercoagulability, and those involving the deep veins proximal to the knee are ...

  6. 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.

  7. Classic crush and DK crush stenting techniques.

    Science.gov (United States)

    Zhang, Jun-Jie; Chen, Shao-Liang

    2015-01-01

    Clinical data have supported the advantages of the double kissing (DK) crush technique, which consists of stenting the side branch (SB), balloon crush, first kissing, stenting the main vessel (MV) and final kissing balloon inflation, for complex coronary bifurcation lesions compared to other stenting techniques. Careful rewiring from the proximal cell of the MV stent to make sure the wire is in the true lumen of the SB stent is key to acquiring optimal angiographic results. Balloon anchoring from the MV, alternative inflation and each kissing inflation using large enough non-compliant balloons at high pressure, and the proximal optimisation technique are mandatory to improve both angiographic and clinical outcomes. Stratification of a given bifurcation lesion is recommended before decision making.

  8. Minimal asymmetric dark matter

    Directory of Open Access Journals (Sweden)

    Sofiane M. Boucenna

    2015-09-01

    Full Text Available In the early Universe, any particle carrying a conserved quantum number and in chemical equilibrium with the thermal bath will unavoidably inherit a particle–antiparticle asymmetry. A new particle of this type, if stable, would represent a candidate for asymmetric dark matter (DM with an asymmetry directly related to the baryon asymmetry. We study this possibility for a minimal DM sector constituted by just one (generic SU(2L multiplet χ carrying hypercharge, assuming that at temperatures above the electroweak phase transition an effective operator enforces chemical equilibrium between χ and the Higgs boson. We argue that limits from DM direct detection searches severely constrain this scenario, leaving as the only possibilities scalar or fermion multiplets with hypercharge y=1, preferentially quintuplets or larger SU(2 representations, and with a mass in the few TeV range.

  9. Asymmetric black dyonic holes

    Directory of Open Access Journals (Sweden)

    I. Cabrera-Munguia

    2015-04-01

    Full Text Available A 6-parametric asymptotically flat exact solution, describing a two-body system of asymmetric black dyons, is studied. The system consists of two unequal counterrotating Kerr–Newman black holes, endowed with electric and magnetic charges which are equal but opposite in sign, separated by a massless strut. The Smarr formula is generalized in order to take into account their contribution to the mass. The expressions for the horizon half-length parameters σ1 and σ2, as functions of the Komar parameters and of the coordinate distance, are displayed, and the thermodynamic properties of the two-body system are studied. Furthermore, the seven physical parameters satisfy a simple algebraic relation which can be understood as a dynamical scenario, in which the physical properties of one body are affected by the ones of the other body.

  10. Asymmetric Realized Volatility Risk

    Directory of Open Access Journals (Sweden)

    David E. Allen

    2014-06-01

    Full Text Available In this paper, we document that realized variation measures constructed from high-frequency returns reveal a large degree of volatility risk in stock and index returns, where we characterize volatility risk by the extent to which forecasting errors in realized volatility are substantive. Even though returns standardized by ex post quadratic variation measures are nearly Gaussian, this unpredictability brings considerably more uncertainty to the empirically relevant ex ante distribution of returns. Explicitly modeling this volatility risk is fundamental. We propose a dually asymmetric realized volatility model, which incorporates the fact that realized volatility series are systematically more volatile in high volatility periods. Returns in this framework display time varying volatility, skewness and kurtosis. We provide a detailed account of the empirical advantages of the model using data on the S&P 500 index and eight other indexes and stocks.

  11. Urine-compatible polymer for long-term ureteral stenting.

    Science.gov (United States)

    Cardella, J F; Castaneda-Zuniga, W R; Hunter, D W; Hulbert, J C; Amplatz, K

    1986-11-01

    Internal double-J ureteral stents were designed from a urine-compatible polymer (C-Flex), and 35 stents were placed in patients. The overall patency rate for the stents was 80%, with most stent failures occurring before 2 months; the follow-up period ranged from 2 to 16 months, with a mean follow-up for all stents of 5.0 months. Stents were considered patent at last follow-up only if they had been in place for at least 2 months. No migration or fracture of the stents occurred. Physical properties of urine-exposed stents were compared with those of virgin tubing and tubing exposed for 1 year to shelf conditions. Stent patency was optimized by increasing urine flow by increasing the patient's voluntary oral intake, administering prophylactic oral antibiotics, and avoiding placement of stents into grossly bloody or infected collecting systems.

  12. Primary stent placement for hepatic artery stenosis after liver transplantation.

    Science.gov (United States)

    Le, Linda; Terral, William; Zea, Nicolas; Bazan, Hernan A; Smith, Taylor A; Loss, George E; Bluth, Edward; Sternbergh, W Charles

    2015-09-01

    Significant hepatic artery stenosis (HAS) after orthotopic liver transplantation (OLT) can lead to thrombosis, with subsequent liver failure in 30% of patients. Although operative intervention or retransplantation has been the traditional solution, endovascular therapy has emerged as a less invasive treatment strategy. Prior smaller studies have been conflicting in the relative efficacy of percutaneous transluminal angioplasty (PTA) vs primary stent placement for HAS. This was a single-center retrospective review of all endovascular interventions for HAS after OLT during a 54-month period (August 2009-December 2013). Patients with ultrasound imaging with evidence of severe HAS (peak systolic velocity >400-450 cm/s, resistive index arterial rupture and two hepatic artery dissections. The long-term risk of hepatic artery thrombosis in the entire patient cohort was 3.2%. HAS after OLT can be treated endovascularly with high technical success and excellent primary assisted patency. This series represents the largest reported cohort of endovascular interventions for HAS to date. Initial use of a stent showed a strong trend toward decreasing the need for reintervention. Avoidance of hepatic artery thrombosis is possible in >95% of patients with endovascular treatment and close follow-up. Copyright © 2015 Society for Vascular Surgery. Published by Elsevier Inc. All rights reserved.

  13. Endobiliary Stent Position Changes during External-beam Radiotherapy

    OpenAIRE

    Chu, Kwun-Ye; Eccles, Cynthia L.; Brunner, Thomas B.

    2015-01-01

    Purpose Endobiliary stents can be used as surrogates for pancreatic localization when using cone-beam computed tomography (CBCT) during external-beam radiotherapy (EBRT). This work reports on interfraction stent position changes during EBRT for locally advanced pancreatic cancer (LAPC). Materials and Methods Six patients with endobiliary stents who underwent EBRT for LAPC were assessed. Measurements from the most superior aspect of the stent (sup stent) and the most inferior aspect of the ste...

  14. An increase of VEGF plasma levels is associated with restenosis of drug-eluting stents.

    Science.gov (United States)

    Katsaros, Katharina M; Kastl, Stefan P; Krychtiuk, Konstantin A; Hutter, Randolph; Zorn, Gerlinde; Maurer, Gerald; Huber, Kurt; Wojta, Johann; Christ, Günter; Speidl, Walter S

    2014-06-01

    Drug-eluting stents (DES) reduce late lumen loss compared to bare metal stents but were not able to eradicate in-stent restenosis (ISR) fully. Vascular endothelial growth factor (VEGF) may inhibit late lumen loss through accelerated reendothelialisation, but may also promote neointima formation by proinflammatory effects. The aim of this study was to evaluate whether endogenous plasma levels of VEGF are associated with development of ISR after implantation of DES. We studied 85 patients who were treated with 159 DES. VEGF plasma levels were determined before and 24 hours after PCI. During the eight-month follow-up period, two patients (2.4%) died of cardiovascular causes and 12 patients (14.5% of patients, 7.6% of stents) developed angiographic ISR. Basal VEGF plasma levels were not different in patients with and without ISR at follow-up. In contrast to patients without ISR, VEGF increased significantly upon PCI in patients with ISR (p<0.005). Patients with a decrease of VEGF after PCI had a restenosis rate of 2.4% compared to a restenosis rate of 26.2% in patients with an increase of VEGF after the procedure (p<0.05). This was independent from clinical and angiographic risk factors. Basal plasma levels of VEGF are not associated with the development of ISR. However, an increase of VEGF after PCI is associated with a dramatically increased ISR rate after implantation of DES.

  15. Efectos biológicos de los stents medicados en la circulación coronaria

    Directory of Open Access Journals (Sweden)

    Darío Echeverri, MD

    2010-03-01

    Full Text Available Los stents medicados ofrecen la mejor alternativa disponible no quirúrgica para el tratamiento de la enfermedad coronaria gracias a su demostrada eficacia. Sin embargo, estos excelentes resultados han sido opacados en términos de seguridad, principalmente por la presencia de trombosis de stents de manera tardía o muy tardía. La comprensión de los efectos biológicos que ejercen a nivel de la arteria coronaria luego de su implante, se debe al efecto de la plataforma utilizada, el polímero y la droga que liberan. Los trastornos de reparación vascular inducidos favorecen la trombosis de stents y sus consecuencias clínicas. Se hace una revisión de los diferentes efectos biológicos de los stents medicados en las arterias coronarias, que permite comprender como han surgido rápidamente nuevas versiones en materiales, diseños, polímeros y medicamentos que reducen los efectos adversos a nivel coronario, mejorando su eficacia y seguridad.

  16. 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......, the aneurysm had healed in the Nevo, but was still present in the Cypher stented segment. We hypothesize that aneurysm formation was induced by sirolimus and the polymer of the implanted stents, and that subsequent healing was possible in the Nevo stent after degradation of the polymer....

  17. Randomized comparison of coronary bifurcation stenting with the crush versus the culotte technique using sirolimus eluting stents: the Nordic stent technique study

    DEFF Research Database (Denmark)

    Erglis, Andrejs; Kumsars, Indulis; Niemelä, Matti

    2009-01-01

    BACKGROUND: In a number of coronary bifurcation lesions, both the main vessel and the side branch need stent coverage. Using sirolimus eluting stents, we compared 2 dedicated bifurcation stent techniques, the crush and the culotte techniques in a randomized trial with separate clinical and angiog......BACKGROUND: In a number of coronary bifurcation lesions, both the main vessel and the side branch need stent coverage. Using sirolimus eluting stents, we compared 2 dedicated bifurcation stent techniques, the crush and the culotte techniques in a randomized trial with separate clinical...

  18. 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.

  19. Nanotechnology-based gene-eluting stents.

    Science.gov (United States)

    Goh, Debbie; Tan, Aaron; Farhatnia, Yasmin; Rajadas, Jayakumar; Alavijeh, Mohammad S; Seifalian, Alexander M

    2013-04-01

    Cardiovascular disease is one of the major causes of death in the world. Coronary stenting in percutaneous coronary intervention (PCI) has revolutionized the field of cardiology. Coronary stenting is seen as a less invasive procedure compared to coronary artery bypass graft (CABG) surgery. Two main types of stents currently exist in the market: bare-metal stents (BMS) and drug-eluting stents (DES). DES were developed in response to problems associated with BMS use, like neointimal hyperplasia leading to restenosis. However, the use of DES engendered other problems as well, like late stent thrombosis (ST), which is a serious and lethal complication. Gene-eluting stents (GES) have recently been proposed as a novel method of circumventing problems seen in BMS and DES. Utilizing nanotechnology, sustained and localized delivery of genes can mitigate problems of restenosis and late ST by accelerating the regenerative capacity of re-endothelialization. Therefore this review seeks to explore the realm of GES as a novel alternative to BMS and DES, and its potential implications in the field of nanotechnology and regenerative medicine.

  20. Forming of magnesium alloy microtubes in the fabrication of biodegradable stents

    Directory of Open Access Journals (Sweden)

    Lixiao Wang

    2014-10-01

    Full Text Available Magnesium alloys have, in recent years, been recognized as highly promising biodegradable materials, especially for vascular stent applications. Forming of magnesium alloys into high-precision thin-wall tubes has however presented a technological barrier in the fabrication of vascular stents, because of the poor workability of magnesium at room temperature. In the present study, the forming processes, i.e., hot indirect extrusion and multi-pass cold drawing were used to fabricate seamless microtubes of a magnesium alloy. The magnesium alloy ZM21 was selected as a representative biomaterial for biodegradable stent applications. Microtubes with an outside diameter of 2.9 mm and a wall thickness of 0.2 mm were successfully produced at the fourth pass of cold drawing without inter-pass annealing. Dimensional evaluation showed that multi-pass cold drawing was effective in correcting dimensional non-uniformity arising from hot indirect extrusion. Examinations of the microstructures of microtubes revealed the generation of a large number of twins as a result of accumulated work hardening at the third and fourth passes of cold drawing, corresponding to the significantly raised forming forces. The work demonstrated the viability of the forming process route selected for the fabrication of biodegradable magnesium alloy microtubes.

  1. Clinical Study on Using (125)I Seeds Articles Combined with Biliary Stent Implantation in the Treatment of Malignant Obstructive Jaundice.

    Science.gov (United States)

    Wang, Tao; Liu, Sheng; Zheng, Yan-Bo; Song, Xue-Peng; Sun, Bo-Lin; Jiang, Wen-Jin; Wang, Li-Gang

    2017-08-01

    Aim: To study the feasibility and curative effect of(125)I seeds articles combined with biliary stent implantation in the treatment of malignant obstructive jaundice. Patients and Methods: Fifty patients with malignant obstructive jaundice were included. Twenty-four were treated by biliary stent implantation combined with intraluminal brachytherapy by (125)I seeds articles as the experimental group, while the remaining 26 were treated by biliary stent implantation only as the control group. The goal of this study was to evaluate total bilirubin, direct bilirubin and tumor markers (cancer antigen (CA)-199, CA-242 and carcinoembryonic antigen (CEA)), as well as biliary stent patency status and survival time before and after surgery. Results: Jaundice improved greatly in both groups. The decreases of CA-199 and CA-242 had statistical significance (p=0.003 and p=0.004) in the experimental group. The ratio of biliary stent patency was 83.3% (20/24) in the experimental group and 57.7% (15/26) in the control group (p=0.048). The biliary stent patency time in the experimental group was 1~15.5 (mean=9.84) months. The biliary stent patency time in the control group was 0.8~9 (mean=5.57) months, which was statistically significant (p=0.018). The median survival time was 10.2 months in the experimental group, while 5.4 months in control group (pjaundice possibly by inhibiting the proliferation of vascular endothelial cells and the growth of tumor. Copyright© 2017, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.

  2. Frequency and Effect of Access-Related Vascular Injury and Subsequent Vascular Intervention After Transcatheter Aortic Valve Replacement.

    Science.gov (United States)

    Dencker, Ditte; Taudorf, Mikkel; Luk, N H Vincent; Nielsen, Michael B; Kofoed, Klaus F; Schroeder, Torben V; Søndergaard, Lars; Lönn, Lars; De Backer, Ole

    2016-10-15

    Vascular access and closure remain a challenge in transcatheter aortic valve replacement (TAVR). This single-center study aimed to report the incidence, predictive factors, and clinical outcomes of access-related vascular injury and subsequent vascular intervention. During a 30-month period, 365 patients underwent TAVR and 333 patients (94%) were treated by true percutaneous transfemoral approach. Of this latter group, 83 patients (25%) had an access-related vascular injury that was managed by the use of a covered self-expanding stent (n = 49), balloon angioplasty (n = 33), or by surgical intervention (n = 1). In 16 patients (5%), the vascular injury was classified as a major vascular complication. Absence of a preprocedural computed tomography angiography (CTA) of the iliofemoral arteries (OR 2.04, p = 0.007) and female gender (OR 2.18, p = 0.004) were independent predictors of the need for access-related vascular intervention. In addition, a high sheath/common femoral artery ratio as measured on preoperative CTA was associated with a higher rate of post-TAVR vascular intervention. The radiation dose, iodine contrast volume, transfusion need, length of hospitalization, and 30-day mortality were not significantly different between patients with versus without access-related vascular intervention. In conclusion, access-related vascular intervention in patients who underwent transfemoral-TAVR is not uncommon. Female gender and a high sheath/common femoral artery ratio are risk factors for access-related vascular injury, whereas preprocedural planning with CTA of the access vessels may reduce the risk of vascular injury. Importantly, most access-related vascular injuries may be treated by percutaneous techniques with similar clinical outcomes to patients without vascular injuries. Copyright © 2016 Elsevier Inc. All rights reserved.

  3. A modern generation of drug-eluting stents. Focusing on a sirolimus-eluting stent Calypso

    Directory of Open Access Journals (Sweden)

    А. Н. Кудряшов

    2017-04-01

    Full Text Available The review deals with the evolution of interventional coronary procedures and development of the state-of-art coronary stent market. Emphasis in the review is placed on comprehensive analysis of technical characteristics of the world’s most popular coronary stents versus a Russian bioresorbable sirolimus-eluting stent “Calipso”.Received 13 January 2017. Accepted 17 March 2017.Conflict of interest: Kudryashov A.N., Trebushat D.V. are “Angioline” Company employees, the producer of “Kalipso” coronary stent. Kretov E.I. served as executive editor of “Endovascular surgery” section. All other authors declare no conflict of interest.

  4. Asymmetric bifurcated halogen bonds.

    Science.gov (United States)

    Novák, Martin; Foroutan-Nejad, Cina; Marek, Radek

    2015-03-07

    Halogen bonding (XB) is being extensively explored for its potential use in advanced materials and drug design. Despite significant progress in describing this interaction by theoretical and experimental methods, the chemical nature remains somewhat elusive, and it seems to vary with the selected system. In this work we present a detailed DFT analysis of three-center asymmetric halogen bond (XB) formed between dihalogen molecules and variously 4-substituted 1,2-dimethoxybenzene. The energy decomposition, orbital, and electron density analyses suggest that the contribution of electrostatic stabilization is comparable with that of non-electrostatic factors. Both terms increase parallel with increasing negative charge of the electron donor molecule in our model systems. Depending on the orientation of the dihalogen molecules, this bifurcated interaction may be classified as 'σ-hole - lone pair' or 'σ-hole - π' halogen bonds. Arrangement of the XB investigated here deviates significantly from a recent IUPAC definition of XB and, in analogy to the hydrogen bonding, the term bifurcated halogen bond (BXB) seems to be appropriate for this type of interaction.

  5. Magnetically Modified Asymmetric Supercapacitors Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This Small Business Innovation Research Phase I project is for the development of an asymmetric supercapacitor that will have improved energy density and cycle life....

  6. Wall shear stress distributions on stented patent ductus arteriosus

    Science.gov (United States)

    Kori, Mohamad Ikhwan; Jamalruhanordin, Fara Lyana; Taib, Ishkrizat; Mohammed, Akmal Nizam; Abdullah, Mohammad Kamil; Ariffin, Ahmad Mubarak Tajul; Osman, Kahar

    2017-04-01

    A formation of thrombosis due to hemodynamic conditions after the implantation of stent in patent ductus arteriosus (PDA) will derived the development of re-stenosis. The phenomenon of thrombosis formation is significantly related to the distribution of wall shear stress (WSS) on the arterial wall. Thus, the aims of this study is to investigate the distribution of WSS on the arterial wall after the insertion of stent. Three dimensional model of patent ductus arteriosus inserted with different types of commercial stent are modelled. Computational modelling is used to calculate the distributions of WSS on the arterial stented PDA. The hemodynamic parameters such as high WSS and WSSlow are considered in this study. The result shows that the stented PDA with Type III stent has better hemodynamic performance as compared to others stent. This model has the lowest distributions of WSSlow and also the WSS value more than 20 dyne/cm2. From the observed, the stented PDA with stent Type II showed the highest distributions area of WSS more than 20 dyne/cm2. This situation revealed that the high possibility of atherosclerosis to be developed. However, the highest distribution of WSSlow for stented PDA with stent Type II indicated that high possibility of thrombosis to be formed. In conclusion, the stented PDA model calculated with the lowest distributions of WSSlow and WSS value more than 20dyne/cm2 are considered to be performed well in stent hemodynamic performance as compared to other stents.

  7. Multicatalyst system in asymmetric catalysis

    CERN Document Server

    Zhou, Jian

    2014-01-01

    This book introduces multi-catalyst systems by describing their mechanism and advantages in asymmetric catalysis.  Helps organic chemists perform more efficient catalysis with step-by-step methods  Overviews new concepts and progress for greener and economic catalytic reactions  Covers topics of interest in asymmetric catalysis including bifunctional catalysis, cooperative catalysis, multimetallic catalysis, and novel tandem reactions   Has applications for pharmaceuticals, agrochemicals, materials, and flavour and fragrance

  8. Asymmetric Ion-Pairing Catalysis

    Science.gov (United States)

    Brak, Katrien

    2014-01-01

    Charged intermediates and reagents are ubiquitous in organic transformations. The interaction of these ionic species with chiral neutral, anionic, or cationic small molecules has emerged as a powerful strategy for catalytic, enantioselective synthesis. This review describes developments in the burgeoning field of asymmetric ion-pairing catalysis with an emphasis on the insights that have been gleaned into the structural and mechanistic features that contribute to high asymmetric induction. PMID:23192886

  9. Blood flow and stem cells in vascular disease.

    Science.gov (United States)

    Zhang, Cheng; Zeng, Lingfang; Emanueli, Costanza; Xu, Qingbo

    2013-07-15

    It is well known that the altered blood flow is related to vascular diseases, including atherosclerosis, restenosis, and arteriosclerosis, which preferentially located at areas with the disturbed blood flow, suggesting that altered biomechanical stress may exert their effect on the vascular disease. Recent evidence indicated the presence of abundant stem/progenitor cells in the vessel wall, in which laminar shear stress can stimulate these cells to differentiate towards endothelial lineage, while cyclic strain results in smooth muscle differentiation. In line with this, it was evidenced that altered biomechanical stress in stented vessels may lead to 'wrong' direction of vascular stem cell differentiation resulting in restenosis. However, the underlying mechanisms are not well understood. In this article, we will give an overview of the effect of the local flow pattern on stem/progenitor cell differentiation and the possible mechanism on how the blood flow influences stem cell behaviours in the development of vascular diseases.

  10. [Progress in genetic and epigenetic research on in-stent restenosis after percutaneous coronary interventions].

    Science.gov (United States)

    Kang, Yan-hong; Lao, Hai-yan; Yu, Xi-yong; Chen, Ji-yan; Zhong, Shi-long

    2012-02-01

    Coronary heart disease is one of the most important causes of death in human, and consumes vast medical resources. Percutaneous coronary intervention (PCI) has been a significant breakthrough for its treatment. However, clinical application has been hampered by in-stent restenosis (ISR). Although drug eluting stent (DES) has reduced the occurrence of restenosis, incidence of ISR is still about 5% to 10%. The main reasons for restenosis after PCI are hyperplasia of vascular endothelial cells and smooth muscle cell migration. The exact mechanism of personalized differences in restenosis is not clear yet, but there may be a variety of risk factors. In addition to aging, smoking and diabetes, an increasing number of studies have found that genetic and epigenetic factors play an important role in ISR. In this article, authors have reviewed genetic and epigenetic factors on the progression of ISR, which may help to determine the genetic risk factors in patients with ISR after PCI.

  11. Nanotextured stainless steel for improved corrosion resistance and biological response in coronary stenting

    Science.gov (United States)

    Mohan, Chandini C.; Prabhath, Anupama; Cherian, Aleena Mary; Vadukumpully, Sajini; Nair, Shantikumar V.; Chennazhi, Krishnaprasad; Menon, Deepthy

    2014-12-01

    Nanosurface engineering of metallic substrates for improved cellular response is a persistent theme in biomaterials research. The need to improve the long term prognosis of commercially available stents has led us to adopt a `polymer-free' approach which is cost effective and industrially scalable. In this study, 316L stainless steel substrates were surface modified by hydrothermal treatment in alkaline pH, with and without the addition of a chromium precursor, to generate a well adherent uniform nanotopography. The modified surfaces showed improved hemocompatibility and augmented endothelialization, while hindering the proliferation of smooth muscle cells. Moreover, they also exhibited superior material properties like corrosion resistance, surface integrity and reduced metal ion leaching. The combination of improved corrosion resistance and selective vascular cell viability provided by nanomodification can be successfully utilized to offer a cell-friendly solution to the inherent limitations pertinent to bare metallic stents.

  12. Incomplete stent apposition after implantation of paclitaxel-eluting stents or bare metal stents: insights from the randomized TAXUS II trial.

    NARCIS (Netherlands)

    K. Tanabe (Kengo); P.W.J.C. Serruys (Patrick); M. Degertekin (Muzaffer); E. Grube (Eberhard); G. Guagliumi (Giulio); W. Urbaszek (Wilhelm); J.J.R.M. Bonnier (Hans); J.M. Lanblanche (Jean-Michel); T. Siminiak (Tomasz); J. Nordrehaug (Jan); H. Figulla (Hans); J. Drzewiecki (Janusz); A. Banning (Adrian); K. Hauptmann (Karl); D. Dudek (Dariusz); N. Bruining (Nico); R. Hamers (Ronald); A. Hoye (Angela); J.M.R. Ligthart (Jürgen); C. Disco (Clemens); J. Koglin (Jörg); M.E. Russell (Mary); A. Colombo (Antonio)

    2005-01-01

    textabstractBACKGROUND: The clinical impact of late incomplete stent apposition (ISA) for drug-eluting stents is unknown. We sought to prospectively investigate the incidence and extent of ISA after the procedure and at 6-month follow-up of paclitaxel-eluting stents in comparison with bare metal

  13. Stenting of Extracranial Carotid Artery Stenosis

    Science.gov (United States)

    Koshimae, N.; Morimoto, T.; Nagata, K.

    2003-01-01

    Summary The purpose of this study is to evaluate our cases of cervical internal carotid artery stenosis for safty stenting. We investigate the preoperative internal carotid artery stenosis using by integrated backscatter (IBS) method of ultra sonography, comparing with the thirty five surgical specimens as to their nature, histological structure, thickness of fibrous cap. We choose the protection method according to plaque structure, and placed Easy-Wall stent or Smart stent after prePTA. We added post PTA according to the extent of expansion and IVUS findings. Calibrated IBS = IBS value (ROI) /intinal IBS value of ‘bleeding’, ‘lipiď, ‘thrombus’, fiber, ‘hyalinization’ were -27.5, -22.5, -15.2, -11.1, +2.1. That of the thin fibrous cap were -10.9*, that of thic fibrous cap were -2.4 (*p safty stenting. PMID:20591243

  14. Percutaneous endovascular stent-graft treatment of aortic aneurysms and dissections: new techniques and initial experience

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Do Yun; Choi, Dong Hoon; Kang, Sung Gwon; Lee, Kwang Hoon; Won, Jong Yun [Yonsei University College of Medicine, Seoul (Korea, Republic of); Kang, Sung Gwon [Chosun University College of Medicine, Gwangju (Korea, Republic of); Won, Je Whan [Aju University College of Medicine, Suwon (Korea, Republic of); Song, Ho Young [Ulsan University College of Medicine, Seoul (Korea, Republic of)

    2003-01-01

    To evaluate the feasibility, safety and effectiveness of a newly designed percutaneously implanted separate stent-graft (SSG) for the treatment of aortic aneurysms and dissections. Using a percutaneous technique, SSG placement (in the descending thoracic aorta in 26 cases and infrarenal abdominal aorta in 24) was attempted in 50 patients with aortic aneurysms (n=27) or dissection (n=23). All SSGs were individually constructed using self-expandable nitinol stents and a Dacron graft, and were introduced through a 12 F sheath and expanded to a diameter of 20-34 mm. In all cases, vascular access was through the femoral artery. The clinical status of each patient was monitored, and postoperative CT was performed within one week of the procedure and at 3-6 month intervals afterwards. Endovascular stent-graft deployment was technically successful in 49 of 50 patients (98%). The one failure was due to torsion of the unsupported graft during deployment. Successful exclusion of aneurysms and the primary entry tears of dissections was achieved in all but three patients with aortic dissection. All patients in whom technical success was achieved showed complete thrombosis of the thoracic false lumen or aneurysmal sac, and the overall technique success rate was 92%. In addition, sixteen patients demonstrated complete resolution of the dissected thoracic false lumen (n=9) or aneurysmal sac (n=7). Immediate post-operative complications occurred at the femoral puncture site in one patient with an arteriovenous fistula, and in two, a new saccular aneurysm developed at the distal margin of the stent. No patients died, and there was no instance of paraplegia, stroke, side-branch occlusion or infection during the subsequent mean follow-up period of 9.4 (range, 2 to 26) months. In patients with aortic aneurysm and dissection, treatment with a separate percutaneously inserted stent-graft is technically feasible, safe, and effective.

  15. A finite element study of balloon expandable stent for plaque and arterial wall vulnerability assessment

    Science.gov (United States)

    Karimi, Alireza; Navidbakhsh, Mahdi; Razaghi, Reza

    2014-07-01

    The stresses induced within plaque tissues and arterial layers during stent expansion inside an atherosclerotic artery can be exceeded from the yield stresses of those tissues and, consequently, lead to plaque or arterial layer rupture. The distribution and magnitude of the stresses in each component involved in stenting might be clearly different for different plaque types and different arterial layers. In this study, a nonlinear finite element simulation was employed to investigate the effect of plaque composition (calcified, cellular, and hypocellular) on the stresses induced in the arterial layers (intima, media, and adventitia) during implantation of a balloon expandable coronary stent into a stenosed artery. The atherosclerotic artery was assumed to consist of a plaque and normal/healthy arterial tissues on its outer side. The results indicated a significant influence of plaque types on the maximum stresses induced within the plaque wall and arterial layers during stenting but not when computing maximum stress on the stent. The stress on the stiffest calcified plaque wall was in the fracture level (2.38 MPa), whereas cellular and hypocellular plaques remain stable owing to less stress on their walls. Regardless of plaque types, the highest von Mises stresses were observed on the stiffest intima layer, whereas the lowest stresses were seen to be located in less stiff media layer. The computed stresses on the intima layer were found to be high enough to initiate a rupture in this stiff layer. These findings suggest a higher risk of arterial vascular injury for the intima layer, while a lower risk of arterial injury for the media and adventitia layers.

  16. Asymmetric Gepner models (revisited)

    Energy Technology Data Exchange (ETDEWEB)

    Gato-Rivera, B. [NIKHEF Theory Group, Kruislaan 409, 1098 SJ Amsterdam (Netherlands)] [Instituto de Fisica Fundamental, CSIC, Serrano 123, Madrid 28006 (Spain); Schellekens, A.N., E-mail: t58@nikhef.n [NIKHEF Theory Group, Kruislaan 409, 1098 SJ Amsterdam (Netherlands)] [Instituto de Fisica Fundamental, CSIC, Serrano 123, Madrid 28006 (Spain)] [IMAPP, Radboud Universiteit, Nijmegen (Netherlands)

    2010-12-11

    We reconsider a class of heterotic string theories studied in 1989, based on tensor products of N=2 minimal models with asymmetric simple current invariants. We extend this analysis from (2,2) and (1,2) spectra to (0,2) spectra with SO(10) broken to the Standard Model. In the latter case the spectrum must contain fractionally charged particles. We find that in nearly all cases at least some of them are massless. However, we identify a large subclass where the fractional charges are at worst half-integer, and often vector-like. The number of families is very often reduced in comparison to the 1989 results, but there are no new tensor combinations yielding three families. All tensor combinations turn out to fall into two classes: those where the number of families is always divisible by three, and those where it is never divisible by three. We find an empirical rule to determine the class, which appears to extend beyond minimal N=2 tensor products. We observe that distributions of physical quantities such as the number of families, singlets and mirrors have an interesting tendency towards smaller values as the gauge groups approaches the Standard Model. We compare our results with an analogous class of free fermionic models. This displays similar features, but with less resolution. Finally we present a complete scan of the three family models based on the triply-exceptional combination (1,16{sup *},16{sup *},16{sup *}) identified originally by Gepner. We find 1220 distinct three family spectra in this case, forming 610 mirror pairs. About half of them have the gauge group SU(3)xSU(2){sub L}xSU(2){sub R}xU(1){sup 5}, the theoretical minimum, and many others are trinification models.

  17. Comparison of Drug-Eluting Stents and Bare-Metal Stents in Reinfarction on ST-Elevation Myocardial Infarction Patients

    Directory of Open Access Journals (Sweden)

    Oryza G. Prabu

    2015-06-01

    Full Text Available AbstractSTEMI is part of the acute coronary syndromes world which is one of the most common causes of death in the world. One of STEMI treatment is percutaneous coronary intervention (PCI using stents, such as drug-eluting and bare-metal stents. These stents can reduce the recurrence of a subsequent heart attack. Three articles were found from the online databases then critical appraisal was performed. The three articles have ARR range of 0.3% -3.6%, RRR 5%-44,3% and NNT 29-333 patients.The three articles stated that drug-eluting stents compared to bare-metal stents did not have significant difference in the occurance of reinfarction in STEMI patients.Keywords: STEMI, drug eluting stent, bare metal stent, recurrence, myocardial infarctionAbstrakSTEMI adalah bagian dari sindrom koroner akut yang merupakan salah satu penyebab kematian tersering di dunia. Salah satu terapi STEMI adalah percutaneus coronary intervention (PCI menggunakan stent seperti drug-eluting stents serta bare-metal stents yang dapat menurunkan rekurensi serangan jantung berikutnya. Dari pencarian didapatkan 3 artikel yang kemudian ditelaah kritis. Ketiga artikel memiliki rentang ARR 0,3%-3,6%, RRR 5%-44,3% danNNT 29-333 pasien. Ketiga artikel menyatakan tidak ada perbedaan bermakna antara penggunaan drug-eluting stents dan bare-metal stents dalam menurunkan rekurensi serangan infark miokard.Kata kunci: STEMI, drug eluting stents, bare metal stents, rekurensi, infark miokard

  18. RNA-Eluting Surfaces for the Modulation of Gene Expression as A Novel Stent Concept

    Directory of Open Access Journals (Sweden)

    Olivia Koenig

    2017-02-01

    Full Text Available Presently, a new era of drug-eluting stents is continuing to improve late adverse effects such as thrombosis after coronary stent implantation in atherosclerotic vessels. The application of gene expression–modulating stents releasing specific small interfering RNAs (siRNAs or messenger RNAs (mRNAs to the vascular wall might have the potential to improve the regeneration of the vessel wall and to inhibit adverse effects as a new promising therapeutic strategy. Different poly (lactic-co-glycolic acid (PLGA resomers for their ability as an siRNA delivery carrier against intercellular adhesion molecule (ICAM-1 with a depot effect were tested. Biodegradability, hemocompatibility, and high cell viability were found in all PLGAs. We generated PLGA coatings with incorporated siRNA that were able to transfect EA.hy926 and human vascular endothelial cells. Transfected EA.hy926 showed significant siICAM-1 knockdown. Furthermore, co-transfection of siRNA and enhanced green fluorescent protein (eGFP mRNA led to the expression of eGFP as well as to the siRNA transfection. Using our PLGA and siRNA multilayers, we reached high transfection efficiencies in EA.hy926 cells until day six and long-lasting transfection until day 20. Our results indicate that siRNA and mRNA nanoparticles incorporated in PLGA films have the potential for the modulation of gene expression after stent implantation to achieve accelerated regeneration of endothelial cells and to reduce the risk of restenosis.

  19. Optical coherence tomography findings after chronic total occlusion interventions: Insights from the “AngiographiC evaluation of the everolimus-eluting stent in chronic Total occlusions” (ACE-CTO) study (NCT01012869)

    Energy Technology Data Exchange (ETDEWEB)

    Sherbet, Daniel P.; Christopoulos, Georgios; Karatasakis, Aris; Danek, Barbara Anna; Kotsia, Anna; Navara, Rachita; Michael, Tesfaldet T.; Roesle, Michele; Rangan, Bavana V.; Haagen, Donald [VA North Texas Healthcare System and University of Texas Southwestern Medical Center, Dallas, TX (United States); Garcia, Santiago [Minneapolis VA Healthcare System and University of Minnesota, Minneapolis, MN (United States); Maniu, Calin [Bon Secours Health System, Suffolk, VA (United States); Pershad, Ashish [Banner Good Samaritan Medical Center, Phoenix, AZ (United States); Abdullah, Shuaib M.; Hastings, Jeffrey L.; Kumbhani, Dharam J.; Luna, Michael; Addo, Tayo; Banerjee, Subhash [VA North Texas Healthcare System and University of Texas Southwestern Medical Center, Dallas, TX (United States); Brilakis, Emmanouil S., E-mail: esbrilakis@gmail.com [VA North Texas Healthcare System and University of Texas Southwestern Medical Center, Dallas, TX (United States)

    2016-10-15

    Background: There is limited information on optical coherence tomography (OCT) findings after percutaneous coronary intervention (PCI) of chronic total occlusions (CTOs). OCT allows high resolution imaging that can enhance understanding of the vascular response after stenting of chronically occluded vessels. Methods: The Angiographic Evaluation of the Everolimus-Eluting Stent in Chronic Total Occlusions (ACE-CTO) study collected angiographic and clinical outcomes from 100 patients undergoing CTO PCI with the everolimus-eluting stent (EES). OCT was performed 8-months post stenting in 62 patients. Every third frame was analyzed throughout the course of the stented arterial segment. Lumen contours were semi-automatically traced and stent struts were manually delineated, with automatic measurement of the strut to lumen distance. Struts on the luminal side of the lumen contour were classified as malapposed if the distance to the lumen contour exceeded 0.108 mm. Results: A total of 44,450 struts in 6047 frames were analyzed, of which 4113 9.3%, 95% confidence intervals [CI] 9.0% to 9.5%) were malapposed and 1230 (2.8%, 95% CI 2.6% to 2.9%) were uncovered. Fifty-five of 62 patients (88.7%, 95% CI 78.5% to 98.4%) had at least one malapposed stent strut and 50 patients (80.7%, 95% CI 69.2% to 88.6%) had at least one uncovered stent strut. Mean strut-intimal thickness of the apposed and malapposed struts was 0.126 ± 0.140 mm and − 0.491 ± 0.440 mm, respectively. Conclusion: High rates of stent strut malapposition and incomplete stent strut coverage were observed after CTO PCI using EES, highlighting unique challenges associated with stent implantation in CTOs. - Highlights: • Percutaneous coronary intervention with drug-eluting stents for chronic total occlusion is associated with a 40% rate of binary in-stent restenosis at 8 months • Of patients who receive a drug eluting stent for a chronic total occlusion 88.7% will have stent strut malapposition and 80.7% will

  20. Research of Customized Aortic Stent Graft Manufacture

    Science.gov (United States)

    Zhang, Lei; Chen, Xin; Liu, Muhan

    2017-03-01

    Thoracic descending aorta diseases include aortic dissection and aortic aneurysm, of which the natural mortality rate is extremely high. At present, endovascular aneurysm repair (EVAR) has been widely used as an effective means for the treatment of descending aortic disease. Most of the existing coating stents are standard design, which are unable to meet the size or structure of different patients. As a result, failure of treatment would be caused by dimensional discrepancy between stent and vessels, which could lead to internal leakage or rupture of blood vessels. Therefore, based on rapid prototyping sacrificial core - coating forming (RPSC-CF), a customized aortic stent graft manufactured technique has been proposed in this study. The aortic stent graft consists of film and metallic stent, so polyether polyurethane (PU) and nickel-titanium (NiTi) shape memory alloy with good biocompatibility were chosen. To minimum film thickness without degrading performance, effect of different dip coating conditions on the thickness of film were studied. To make the NiTi alloy exhibit super-elasticity at body temperature (37°C), influence of different heat treatment conditions on austenite transformation temperature (Af) and mechanical properties were studied. The results show that the customized stent grafts could meet the demand of personalized therapy, and have good performance in blasting pressure and radial support force, laying the foundation for further animal experiment and clinical experiment.

  1. 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.

  2. Ureteral stent discomfort: Etiology and management

    Directory of Open Access Journals (Sweden)

    Ricardo Miyaoka

    2009-01-01

    Full Text Available Objectives : To review the evidence-based literature on the causes, characteristics, and options to manage double J stent-related symptoms. Methods : We performed a Medline database assessment on papers that investigated the prevalence, mechanisms, risk factors, bothersome and management of double-J stent-related symptoms. Articles in English were reviewed and summarized. Results : Stent-related symptoms have a high prevalence and may affect over 80% of patients. They include irritative voiding symptoms including frequency, urgency, dysuria, incomplete emptying; flank and suprapubic pain; incontinence, and hematuria. Assessment tools are important to determine their intensity and allow for comparisons between different points in the timeline. The Urinary Stent Symptom Questionnaire (USSQ is the most proper tool used for this purpose. Management should be focused on the prevention and management of symptoms. In this sense, research has focused on new materials and stent designs that would be more compatible to the physiologic properties of the urinary tract and medications that can ameliorate the sensitivity and motor response of the bladder. Conclusions : Stent-related symptoms are very common in the Urological clinical setting. It is of major importance for the urologist to understand their physiopathology and to be familiar with ways to avoid or manage them.

  3. Carotid Endarterectomy to Remove Retained Solitaire Stent Retriever inside Carotid Stent after Mechanical Thrombectomy.

    Science.gov (United States)

    Cobb, Mary In-Ping Huang; Smith, Tony P; Brown, Patrick A; Gonzalez, L Fernando; Zomorodi, Ali R

    2017-05-01

    Tandem occlusions of the internal carotid artery (ICA) and middle cerebral artery (MCA) occur in up to a third of patients with acute ischemic strokes undergoing endovascular mechanical thrombectomy. Understanding open neurosurgical management of associated complications with this procedure is important. A 67-year-old man with acute onset of left hemiparesis and a tandem right ICA and MCA occlusion. He underwent carotid stent angioplasty of a stenotic ICA, followed by attempted Solitaire stent retrieval of an MCA clot. On withdrawal, the tines of the Solitaire stent lodged inside the Precise carotid stent. The patient was started on aspirin, Plavix, and heparin infusion, and underwent a carotid endarterectomy (CEA) with safe removal of the stents and primary vessel repair. This is the first case reported to date of a Solitaire stent becoming lodged inside a Precise carotid stent, salvaged by CEA with safe removal of the stents and primary vessel repair. We discuss the timing, indication, alternatives, and technical nuances of a CEA in this setting. Copyright © 2017 National Stroke Association. Published by Elsevier Inc. All rights reserved.

  4. iStent trabecular micro-bypass stent for open-angle glaucoma

    Directory of Open Access Journals (Sweden)

    Le K

    2014-09-01

    Full Text Available Kim Le, Hady Saheb Department of Ophthalmology, McGill University, Montreal, QC, Canada Abstract: Trabecular micro-bypass stents, commonly known as iStents, are micro-invasive glaucoma surgery (MIGS devices used to treat open-angle glaucoma. Like other MIGS procedures that enhance trabecular outflow, the iStent lowers intraocular pressure (IOP by creating a direct channel between the anterior chamber and Schlemm’s canal. iStents are typically implanted at the time of phacoemulsification for patients with open-angle glaucoma and visually significant cataracts. This review summarizes the published data regarding the efficacy, safety, and cost considerations of trabecular micro-bypass stents. Most studies found statistically significant reductions in mean IOP and ocular medication use after combined phacoemulsification with single or double iStent implantation. The devices were found to be very safe, with a safety profile similar to that of cataract surgery. Complications were infrequent, with the most common complications being temporary stent obstruction or malposition, which resolved with observation or secondary procedures. Future studies are needed to evaluate long-term outcomes, patient satisfaction, cost effectiveness, and expanded indications. Keywords: iStent, trabecular micro-bypass, glaucoma, MIGS, ab interno, surgery

  5. Technical options for treatment of in-stent restenosis after carotid artery stenting

    NARCIS (Netherlands)

    Pourier, Vanessa E C|info:eu-repo/dai/nl/413970310; de Borst, Gert J.|info:eu-repo/dai/nl/237108151

    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.

  6. A pooled analysis of data comparing sirolimus-eluting stents with bare-metal stents

    NARCIS (Netherlands)

    C.M. Spaulding (Christian); J. Daemen (Joost); H. Boersma (Eric); D.E. Cutlip (Donald); P.W.J.C. Serruys (Patrick)

    2007-01-01

    textabstractBACKGROUND: Although randomized studies have shown a beneficial effect of drug-eluting stents in reducing the risk of repeated revascularization, these trials were underpowered to compare rates of death and myocardial infarction. The long-term safety of drug-eluting stents has been

  7. Stent

    Science.gov (United States)

    ... Elsevier Saunders; 2016:chap 74. White CJ. Atherosclerotic peripheral arterial disease. In: Goldman L, Schafer AI, eds. Goldman's Cecil Medicine . 25th ed. Philadelphia, PA: Elsevier Saunders; 2016:chap 79. Zeidel ML. Obstructive uropathy. In: Goldman L, Schafer AI, eds. Goldman's ...

  8. Prospective rAndomized, single-blind, mulTicenter study of sirolimus-eluting coRonary stent “Calypso” vs everolimus-eluting cOronary stenT “XiencePrime”: results of the PATRIOT trial

    Directory of Open Access Journals (Sweden)

    A. A. Prokhorikhin

    2017-11-01

    Full Text Available Aim. This trial was aimed at comparing the efficacy and safety of sirolimus-eluting coronary stent “Calypso” (Angioline and everolimus-eluting coronary stent “XiencePrime” (Abbott Vascular when used for treatment of ischemic heart disease patients.Methods. The trial included patients suitable for coronary revascularization with coronary stenting. They underwent a standard revascularization procedure and were randomized in 2:1 ratio to receive “Calypso” coronary stent (Angioline (n = 407 or “XiencePrime” coronary stent (AbbottVascular (n = 203. The follow-up period was 12 months. In order to detect restenosis (secondary endpoint, angiographic follow-up was performed in 20% of cases at 12 months. The trial protocol had no limitations regarding the length of lesions, number of target lesions and number of implanted stents. The main exclusion criterion was STEMI. The composite primary endpoint included one-year target lesion-related complications determined as cardiogenic death, target vessel myocardial infarction, clinically indicated target lesion revascularization. The primary endpoint data were evaluated by an independent committee.Results. In the trial, 55% of patients had acute coronary syndrome with ST elevation and type C lesions were detected in 46% of cases. In “Calypso” and “XiencePrime” groups, TLF occurred in 5.4% and 6.4% respectively (absolute risk difference in TLF accounted for 1%, 95% CI [---;2.1%]; p non-inferiority = 0.017. Thus, the hypothesis of non-inferiority of “Calypso” as compared to “XiencePrime” was confirmed. The incidence of stent thrombosis (definite and probable was relatively low and had no significant differences between “Calypso” and “XiencePrime” groups (0.73% and 0%; p>0.05. Definite stent thrombosis was noted in two cases in the “Calypso” group (0.49%, in one case the cause of thrombosis turned out to be incomplete stent expansion after implantation.Conclusion.

  9. 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.

  10. Hemodynamic comparison of stent configurations used for aortoiliac occlusive disease

    NARCIS (Netherlands)

    Groot Jebbink, Erik; Mathai, Varghese; Boersen, Johannes Thomas; Boersen, Johannes T.; Sun, Chao; Slump, Cornelis H.; Goverde, Peter C.J.M.; Versluis, Michel; Reijnen, Michel M.P.J.

    2016-01-01

    Background Endovascular treatment of aortoiliac occlusive disease entails the use of multiple stents to reconstruct the aortic bifurcation. Different configurations have been applied and geometric variations exist, as quantified in previous work. Other studies concluded that specific stent geometry

  11. Asymmetric distances for binary embeddings.

    Science.gov (United States)

    Gordo, Albert; Perronnin, Florent; Gong, Yunchao; Lazebnik, Svetlana

    2014-01-01

    In large-scale query-by-example retrieval, embedding image signatures in a binary space offers two benefits: data compression and search efficiency. While most embedding algorithms binarize both query and database signatures, it has been noted that this is not strictly a requirement. Indeed, asymmetric schemes that binarize the database signatures but not the query still enjoy the same two benefits but may provide superior accuracy. In this work, we propose two general asymmetric distances that are applicable to a wide variety of embedding techniques including locality sensitive hashing (LSH), locality sensitive binary codes (LSBC), spectral hashing (SH), PCA embedding (PCAE), PCAE with random rotations (PCAE-RR), and PCAE with iterative quantization (PCAE-ITQ). We experiment on four public benchmarks containing up to 1M images and show that the proposed asymmetric distances consistently lead to large improvements over the symmetric Hamming distance for all binary embedding techniques.

  12. Asymmetric cation-binding catalysis

    DEFF Research Database (Denmark)

    Oliveira, Maria Teresa; Lee, Jiwoong

    2017-01-01

    The employment of metal salts is quite limited in asymmetric catalysis, although it would provide an additional arsenal of safe and inexpensive reagents to create molecular functions with high optical purity. Cation chelation by polyethers increases the salts' solubility in conventional organic...... solvents, thus increasing their applicability in synthesis. The expansion of this concept to chiral polyethers led to the emergence of asymmetric cation-binding catalysis, where chiral counter anions are generated from metal salts, particularly using BINOL-based polyethers. Alkali metal salts, namely KF...... and KCN, are selectively bound to the catalyst, providing exceptionally high enantioselectivities for kinetic resolutions, elimination reactions (fluoride base), and Strecker synthesis (cyanide nucleophile). Asymmetric cation-binding catalysis was recently expanded to silicon-based reagents, enabling...

  13. Does asymmetric correlation affect portfolio optimization?

    Science.gov (United States)

    Fryd, Lukas

    2017-07-01

    The classical portfolio optimization problem does not assume asymmetric behavior of relationship among asset returns. The existence of asymmetric response in correlation on the bad news could be important information in portfolio optimization. The paper applies Dynamic conditional correlation model (DCC) and his asymmetric version (ADCC) to propose asymmetric behavior of conditional correlation. We analyse asymmetric correlation among S&P index, bonds index and spot gold price before mortgage crisis in 2008. We evaluate forecast ability of the models during and after mortgage crisis and demonstrate the impact of asymmetric correlation on the reduction of portfolio variance.

  14. Hydroxamic acids in asymmetric synthesis.

    Science.gov (United States)

    Li, Zhi; Yamamoto, Hisashi

    2013-02-19

    Metal-catalyzed stereoselective reactions are a central theme in organic chemistry research. In these reactions, the stereoselection is achieved predominantly by introducing chiral ligands at the metal catalyst's center. For decades, researchers have sought better chiral ligands for asymmetric catalysis and have made great progress. Nevertheless, to achieve optimal stereoselectivity and to catalyze new reactions, new chiral ligands are needed. Because of their high metal affinity, hydroxamic acids play major roles across a broad spectrum of fields from biochemistry to metal extraction. Dr. K. Barry Sharpless first revealed their potential as chiral ligands for asymmetric synthesis in 1977: He published the chiral vanadium-hydroxamic-acid-catalyzed, enantioselective epoxidation of allylic alcohols before his discovery of Sharpless asymmetric epoxidation, which uses the titanium-tartrate complex as the chiral reagent. However, researchers have reported few highly enantioselective reactions using metal-hydroxamic acid as catalysts since then. This Account summarizes our research on metal-catalyzed asymmetric epoxidation using hydroxamic acids as chiral ligands. We designed and synthesized a series of new hydroxamic acids, most notably the C2-symmetric bis-hydroxamic acid (BHA) family. V-BHA-catalyzed epoxidation of allylic and homoallylic alcohols achieved higher activity and stereoselectivity than Sharpless asymmetric epoxidation in many cases. Changing the metal species led to a series of unprecedented asymmetric epoxidation reactions, such as (i) single olefins and sulfides with Mo-BHA, (ii) homoallylic and bishomoallylic alcohols with Zr- and Hf-BHA, and (iii) N-alkenyl sulfonamides and N-sulfonyl imines with Hf-BHA. These reactions produce uniquely functionalized chiral epoxides with good yields and enantioselectivities.

  15. Effects of cobalt-chromium everolimus eluting stents or bare metal stent on fatal and non-fatal cardiovascular events

    DEFF Research Database (Denmark)

    Valgimigli, Marco; Sabaté, Manel; Kaiser, Christoph

    2014-01-01

    eluting stents with bare metal stents were selected. The principal investigators whose trials met the inclusion criteria provided data for individual patients. PRIMARY OUTCOMES: The primary outcome was cardiac mortality. Secondary endpoints were myocardial infarction, definite stent thrombosis, definite......OBJECTIVES: To examine the safety and effectiveness of cobalt-chromium everolimus eluting stents compared with bare metal stents. DESIGN: Individual patient data meta-analysis of randomised controlled trials. Cox proportional regression models stratified by trial, containing random effects, were...... or probable stent thrombosis, target vessel revascularisation, and all cause death. RESULTS: The search yielded five randomised controlled trials, comprising 4896 participants. Compared with patients receiving bare metal stents, participants receiving cobalt-chromium everolimus eluting stents had...

  16. Late clinical events after drug-eluting stents: the interplay between stent-related and natural history-driven events

    National Research Council Canada - National Science Library

    Leon, Martin B; Allocco, Dominic J; Dawkins, Keith D; Baim, Donald S

    2009-01-01

    We evaluated the relative contributions of drug-eluting stent-specific and background natural history-driven causes for adverse clinical events between 1 and 5 years, in the paclitaxel-eluting stent (PES...

  17. 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

  18. Impact of stent strut design in metallic stents and biodegradable scaffolds.

    Science.gov (United States)

    Foin, Nicolas; Lee, Renick D; Torii, Ryo; Guitierrez-Chico, Juan Luis; Mattesini, Alessio; Nijjer, Sukhjinder; Sen, Sayan; Petraco, Ricardo; Davies, Justin E; Di Mario, Carlo; Joner, Michael; Virmani, Renu; Wong, Philip

    2014-12-20

    Advances in the understanding of healing mechanisms after stent implantation have led to the recognition of stent strut thickness as an essential factor affecting re-endothelialization and overall long term vessel healing response after Percutaneous Coronary Interventions (PCI). Emergence of Drug-eluting stents (DESs) with anti-proliferative coating has contributed to reducing the incidence of restenosis and Target Lesion Revascularization (TVR), while progress and innovations in stent materials have in the meantime facilitated the design of newer platforms with more conformability and thinner struts, producing lesser injury and improving integration into the vessel wall. Recent advances in biodegradable metal and polymer materials now also allow for the design of fully biodegradable platforms, which are aimed at scaffolding the vessel only temporarily to prevent recoil and constrictive remodeling of the vessel during the initial period required, and are then progressively resorbed thereby avoiding the drawback of leaving an unnecessary implant permanently in the vessel. The aim of this article is to review recent evolution in stent material and stent strut design while understanding their impact on PCI outcomes. The article describes the different metallic alloys and biodegradable material properties and how these have impacted the evolution of stent strut thickness and ultimately outcomes in patients. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  19. Relation of Nickel Allergy with in-Stent Restenosis in Patients Treated with Cobalt Chromium Stents.

    Science.gov (United States)

    Aliağaoğlu, Cihangir; Turan, Hakan; Erden, Ismail; Albayrak, Hülya; Ozhan, Hakan; Başar, Cengiz; Gürlevik, Zehra; Alçelik, Ayşegül

    2012-11-01

    In-stent restenosis (ISR) is the major limitation of percutaneous coronary stenting procedure. The elements like nickel, chromate and molybdenum are known to cause contact allergy. Hypersensitivity reaction, against these metal ions, may be one of the reasons of ISR. Cobalt chromium coronary stents, which are increasingly being used in percutaneous coronary interventions, have more nickel amount than the stainless steel stents. We aimed to investigate the association between nickel hypersensitivity reaction and ISR in patients treated with cobalt chromium coronary stents. Epicutaneous patch tests for nickel were applied to 31 patients who had undergone elective cobalt chromium coronary stent implantation and had ISR in control angiogram. Thirty patients, without ISR, were included as the control group. Patch test results and other clinical variables were compared. There was no statistically significant difference of the mean age, sex, body mass index, rate of hypercholesterolemia, diabetes, hypertension and smoking between the patients with and without ISR. All other lesion characteristics were similar in the 2 groups. According to the patch test results, 7 patients had nickel contact allergy. All of these patients were in the ISR group, which was statistically significant (pcobalt chromium coronary stents and had ISR were found to have significantly more nickel allergy than the control group. Nickel allergy may play role in restenosis pathophysiology.

  20. Platelet recruitment to venous stent thrombi.

    Science.gov (United States)

    McBane, Robert D; Karnicki, Krzysztof; Wysokinski, Waldemar E

    2013-11-01

    Thrombosis following venous stent placement is a morbid clinical outcome. Whether to target platelets or coagulation factors for venous stent thromboprophylaxis remains unclear. We sought to determine whether integrin α(IIb)β3 antagonism with lamifiban would inhibit platelet recruitment to venous stent thrombosis. Anti-thrombotic efficacy was compared between venous and arterial circulations. Pigs received either lamifiban (0.2 mg/kg bolus plus 0.2 mg/kg/h infusion; n = 6) or saline (n = 12). Carotid arteries were crush injured and then harvested 30 min later to provide an assessment of antithrombotic efficacy in the arterial circulation. Iliac venous stents were then deployed and thrombi allowed to propagate for 2 h before harvesting. Platelet deposition was measured by scintillation detection of autologous (111)In-platelets. Venous thrombi were quantified by weight and compared to platelet, Von Willebrand factor (VWF) and fibrinogen content. Arterial platelet deposition (×10(6)/cm(2)) was reduced >80% by lamifiban (398 ± 437) compared to controls (1,540 ± 883; p thrombi occurs in part through the integrin α(IIb)β3 receptor. Unlike arterial thrombosis, inhibition of this receptor is insufficient to prevent venous stent thrombosis.

  1. The impact of precise robotic lesion length measurement on stent length selection: ramifications for stent savings.

    Science.gov (United States)

    Campbell, Paul T; Kruse, Kevin R; Kroll, Christopher R; Patterson, Janet Y; Esposito, Michele J

    2015-09-01

    Coronary stent deployment outcomes can be negatively impacted by inaccurate lesion measurement and inappropriate stent length selection (SLS). We compared visual estimate of these parameters to those provided by the CorPath 200® Robotic PCI System. Sixty consecutive patients who underwent coronary stent placement utilizing the CorPath System were evaluated. The treating physician assessed orthogonal images and provided visual estimates of lesion length and SLS. The robotic system was then used for the same measures. SLS was considered to be accurate when visual estimate and robotic measures were in agreement. Visual estimate SLSs were considered to be "short" or "long" if they were below or above the robotic-selected stents, respectively. Only 35% (21/60) of visually estimated lesions resulted in accurate SLS, whereas 33% (20/60) and 32% (19/60) of the visually estimated SLSs were long and short, respectively. In 5 cases (8.3%), 1 less stent was placed based on the robotic lesion measurement being shorter than the visual estimate. Visual estimate assessment of lesion length and SLS is highly variable with 65% of the cases being inaccurately measured when compared to objective measures obtained from the robotic system. The 32% of the cases where lesions were visually estimated to be short represents cases that often require the use of extra stents after the full lesion is not covered by 1 stent [longitudinal geographic miss (LGM)]. Further, these data showed that the use of the robotic system prevented the use of extra stents in 8.3% of the cases. Measurement of lesions with robotic PCI may reduce measurement errors, need for extra stents, and LGM. Copyright © 2015 Elsevier Inc. All rights reserved.

  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. Modifying effect of dual antiplatelet therapy on incidence of stent thrombosis according to implanted drug-eluting stent type

    NARCIS (Netherlands)

    Camenzind, Edoardo; Boersma, Eric; Wijns, William; Mauri, Laura; Rademaker-Havinga, Tessa; Ordoubadi, Farzin Fath; Suttorp, Maarten J.; Al Kurdi, Mohammad; Steg, Ph Gabriel; Camenzind, E.; Mauri, L.; O'Neill, W.; Serruys, P. W.; Steg, Ph G.; Wijns, W.; Verheugt, F. W. A.; Bertrand, M. E.; Califf, R.; deMets, D.; Wallentin, L.; Bocksch, W.; Bosmans, J.; Garcia, H.; Garg, S.; Hanet, C.; Herrman, J.-P. R.; Kelbaek, H.; Mc Fadden, E.; Radke, P. W.; Rutsch, W.; Tilsted, H. H.; Wykrzykowska, J.; Boersma, E.; Alvarez, C.; Rodriguez, A.; Meredith, I.; Muller, D.; Whitbourn, R.; Worthley, S.; Whelan, A.; Walters, D.; Shetty, S.; New, G.; Cox, S.; Batra, R.; van Gaal, W.; Bellamy, G.; Mayr, H.; Heigert, M.; Huber, K.; Leisch, F.; Desmet, W.; Boland, J.; Schroeder, E.; Chenu, P.; Legrand, V.; Labinaz, M.; Teefy, P.; Bertrand, O.; Gao, R.; Ge, J.; Kala, P.; Cervinka, P.; Ureña, P.; Hartikainen, J.; Steg, G.; Fajadet, J.; Carrie, D.; Gilard, M.; Barragan, P.; Lablanche, J.-M.; Koning, R.; Eltchaninoff, H.; Darremont, O.; Leroy, F.; Bertrand, B.; Robert, G.; Schiele, F.; Chassaing, S.; Bressollette, E.; Brunel, P.; Quilliet, L.; Brunet, J.; Pansieri, M.; Sideris, G.; Stratiev, V.; Teiger, E.; Lebreton, H.; Bonnet, J.-L.; Karsenty, B.; Delarche, N.; Lusson, J.-R.; Cassagnes, J.; Brachmann, J.; Kurowski, V.; Buerke, M.; Schieffer, B.; Scholtz, W.; Wiemer, M.; Fichtlscherer, S.; Schächinger, V.; Kupatt, C.; Boekstegers, P.; Genth-Zotz, S.; Bode, C.; Frey, N.; Neumann, F.-J.; Witzenbichler, B.; Pels, K.; Strasser, R.; Kuck, K.-H.; Hauptmann, K.-E.; Baldus, S.; Heitzer, T.; Haude, M.; Hoffmann, E.; Jung, W.; Hoffmann, S.; Schmitt, C.; Dissmann, M.; Pauschinger, M.; Werner, G.; Braun-Delleus, R.; Burkhardt, D.; Manz, M.; Voudris, V.; Sionis, D.; Kang-Yin, M.-L.; Tse, T.-S.; Merkely, B.; Mehta, A.; Parikh, K.; Kumar, V.; Chandra, P.; Rath, P.; Hiremath, S.; Crean, P.; Daly, K.; Kornowski, R.; Kerner, A.; Mosseri, M.; Jafari, G.; Giudice, P.; Trani, C.; Manari, A.; Prati, F.; Pangrazi, A.; Bolognese, L.; Jeong, M.-H.; Kim, M.-Y.; Kim, H.-S.; Park, S.-J.; Erglis, A.; Kalnins, A.; Wagner, D.; Zambahari, R.; Ong, T.-K.; Sim, K.; den Heijer, P.; Appelman, Y.; Suttorp, M.-J.; de Smet, B.; Koolen, J.; Stella, P.; Harding, S.; Warwick, J.; Maslowski, A.; Abernethy, M.; Devlin, G.; Rotevatn, S.; Myreng, Y.; Ciecwierz, D.; Peruga, J.; Reczuch, K.; Campante Teles, R.; Farto e Abreu, P.; Leitão-Marques, A.; Pereira, H.; Vinereanu, D.; Alkasab, S.; Mhish, H.; Al Kurdi, M.; Al Turki, F.; Wong, P.; teo, S.-G.; Goicolea Ruigomez, F.-J.; Valdés Chávarri, M.; Bethencourt Gonzalez, A.; Iñiguez Romo, A.; López Minguez, J.; Hernández García, J.-M.; Diaz Fernández, J.; Ruiz Salmeron, R.; Martinez Elbal, L.; Zueco, J.; López-Palop, R. F.; Melgares, R.; Diderholm, E.; Kåregren, A.; Herterich, O.; Olivencrona, G.; Fröbert, O.; Roffi, M.; Verin, V.; Girod, G.; Vuilliomenet, A.; Hsieh, I.-C.; Wu, C.-J.; Gershlick, A.; Densem, C.; Doshi, S.; Manoharan, G.; McCarthy, P.; de Belder, M.; Mills, J.; Fath-Ordoubadi, F.; Simpson, I.; Greenwood, J.; Chamberlain-Webber, R.; Khan, Z.; Cotton, J.; Gunning, M.; Smith, D.; Talwar, S.; Holmberg, S.; Purcell, I.; Anderson, R.; Alamgir, F.; Beatt, K.; Kelly, P.; Moussavian, M.; Aji, J.; Prashad, R.; Zankar, A.; Banerjee, S.; Lewis, S.; McLaurin, B.; Douglas, J.; Brener, S.; Gupta, A.; Walters, L.; Driesman, M.; Aycock, R.; Mego, C.; Fisher, D.; Frankel, R.; Satler, L.

    2014-01-01

    Aim To investigate the putative modifying effect of dual antiplatelet therapy (DAPT) use on the incidence of stent thrombosis at 3 years in patients randomized to Endeavor zotarolimus-eluting stent (E-ZES) or Cypher sirolimus-eluting stent (C-SES). Methods and results Of 8709 patients in PROTECT,

  4. Very late stent thrombosis of bare-metal coronary stent nine years after primary percutaneous coronary intervention

    Directory of Open Access Journals (Sweden)

    Đurić Predrag

    2016-01-01

    Full Text Available Introduction. Stent thrombosis (ST in clinical practice can be classified according to time of onset as early (0–30 days after stent implantation, which is further divided into acute ( 30 days and very late (> 12 months. Myocardial reinfaction due to very late ST in a patient receiving antithrombotic therapy is very rare, and potentially fatal. The procedure alone and related mechanical factors seem to be associated with acute/subacute ST. On the other hand, in-stent neoathero-sclerosis, inflammation, premature cessation of antiplatelet therapy, as well as stent fracture, stent malapposition, un-covered stent struts may play role in late/very late ST. Some findings implicate that the etiology of very late ST of bare-metal stent (BMS is quite different from those following drug-eluting stent (DES implantation. Case report. We presented a 56-year old male with acute inferoposterior ST segment elevation myocardial infarction (STEMI related to very late stent thrombosis, 9 years after BMS implantation, despite antithrombotic therapy. Thrombus aspiration was successfully performed followed by percutaneous coronary intervention (PCI with implantation of DES into the pre-viously implanted two stents to solve the in-stent restenosis. Conclusion. Very late stent thrombosis, although fortu-nately very rare, not completely understood, might cause myocardial reinfaction, but could be successfully treated with thrombus aspiration followed by primary PCI. Very late ST in the presented patient might be connected with neointimal plaque rupture, followed by thrombotic events.

  5. 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...

  6. In vivo assessment of stent recoil of biodegradable polymer-coated cobalt-chromium sirolimus-eluting coronary stent system.

    Science.gov (United States)

    Abhyankar, Atul D; Thakkar, Ashok S

    2012-01-01

    Immediate and acute stent recoil has been observed following balloon deflation in normal and diseased coronary arteries, and the degree varies by stent design. A total of 19 patients, who underwent elective stent implantation for single de novo native coronary artery lesions, were enrolled: all patients treated with the biodegradable polymer-coated sirolimus-eluting cobalt-chromium coronary stent system (Supralimus-Core(®)). The immediate, acute and cumulative stent recoil was assessed by quantitative coronary angiography. The cumulative stent recoil was measured at 24 h of stent implantation. The absolute late loss due to recoil was found 0.08 ± 0.19 mm for Immediate Stent Recoil (ISR), 0.05 ± 0.21 mm for Acute Stent Recoil (ASR) and 0.11 ± 0.25 mm for Cumulative Stent Recoil (CSR) respectively. In vivo acute stent recoil of the Supralimus-Core(®) has higher radial strength compared to other available standard drug-eluting stents. Copyright © 2012 Cardiological Society of India. Published by Elsevier B.V. All rights reserved.

  7. Multilink stent promotes less platelet and leukocyte adhesion than a traditional stainless steel stent : An in vitro experimental study

    NARCIS (Netherlands)

    Amoroso, G; van Boven, AJ; Volkers, C; Crijns, HJGM; van Oeveren, W

    Background: Platelet and Leukocyte deposition onto metallic struts can be a crucial factor in the outcome of a coronary stenting procedure. By means of an in vitro, closed-loop circulation model, me aimed to assess blood-stent interaction patterns for a new stainless steel stent (MultiLink, Guidant

  8. Asymmetric hydrogenation using monodentate phosphoramidite ligands

    NARCIS (Netherlands)

    Minnaard, Adriaan J.; Feringa, Ben L.; Lefort, Laurent; De Vries, Johannes G.

    2007-01-01

    Monodentate phosphoramidites are excellent ligands for Rh-catalyzed asymmetric hydrogenations of substituted olefins. Enantioselectivities between 95 and 99% were obtained in the asymmetric hydrogenation of protected alpha- and beta-dehydroamino acids and esters, itaconic acid and esters, aromatic

  9. Asymmetric Synthesis via Chiral Aziridines

    DEFF Research Database (Denmark)

    Tanner, David Ackland; Harden, Adrian; Wyatt, Paul

    1996-01-01

    A series of chiral bis(aziridines) has been synthesised and evaluated as chelating ligands for a variety of asymmetric transformations mediated by metals [Os (dihydroxylation), Pd (allylic alkylation) Cu (cyclopropanation and aziridination, Li (1,2-addition of organolithiums to imines)]. In the b...

  10. Structure of asymmetrical peptide dendrimers

    NARCIS (Netherlands)

    Okrugin, B.M.; Neelov, I.M.; Leermakers, F.A.M.; Borisov, Oleg V.

    2017-01-01

    Structural properties of asymmetric peptide dendrimers up to the 11th generation are studied on the basis of the self-consistent field Scheutjens-Fleer numerical approach. It is demonstrated that large scale properties such as, e.g., the gyration radius, are relatively weakly affected by the

  11. Malignant duodenal obstructions: palliative treatment with covered expandable nitinol stent

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hyun Chul; Jung, Gyoo Sik; Lee, Sang Hee; Kim, Sung Min; Oh, Kyung Seung; Huh, Jin Do; Cho, Young Duk [College of Medicine, Kosin Univ, Pusan (Korea, Republic of); Song, Ho Young [College of Medicine, Ulsan Univ., Seoul (Korea, Republic of)

    2002-04-01

    To evaluate the feasibility and clinical effectiveness of using a polyurethane-covered expandable nitinol stent in the palliative treatment of malignant duodenal obstruction. Under fluoroscopic guidance, a polyurethane-covered expandable nitinol stent was placed in 12 consecutive patients with malignant duodenal obstructions. All presented with severe nausea and recurrent vomiting. The underlying causes of obstruction were duodenal carcinoma (n=4), pancreatic carcinoma (n=4), gall bladder carcinoma (n=2), distal CBD carcinoma (n=1), and uterine cervical carcinoma (n=1). The sites of obstruction were part I (n=1), part II (n=8), and III (n=3). Due to pre-existing jaundice, eight patients with part II obstructions underwent biliary decompression prior to stent placement. An introducer sheath with a 6-mm outer diameter and stents 16 mm in diameter were employed, and to place the stent, and after-loading technique was used. Stent placement was technically successful in ten patients, and no procedural complications occuured. In one of two patients in whom there was technical failure, and in whom the obstructions were located in part III, the stent was placed transgastrically. Stent migration occurred in one patient four days after the procedure, and treatment involved the palcement of a second, uncovered, nitinol stent. After stent placement, symptoms improved in all patients. During follow-up, obstructive symptoms due to stent stenosis (n=1), colonic obstruction (n=1), and multiple small bowel obstruction (n=1) recurred in three patients. Two of these were treated by placing additional stents in the duodenum and colon, respectively. One of the eight patients in whom a stent was placed in the second portion of the duodenum developed jaundice. The patients died a mean 14 (median, 9) weeks after stent placement. The placement of a polyurethane-covered expandable nitinol stent seems to be technically feasible, safe and effective for the palliative treatment of malignant

  12. Endovascular repair of an abdominal aortic aneurysm in a patient with stenosis of bilateral common iliac artery stents.

    Science.gov (United States)

    Daab, Leo J; Aidinian, Gilbert; Weber, Michael A; Kembro, Ronald J; Cook, Patrick R

    2011-01-01

    The explosion in endovascular interventions for peripheral vascular disease has resulted in procedures being used by a multitude of specialties. Nonvascular surgeons performing these interventions can create scenarios that may make future vascular interventions difficult. In this article, we present a case report illustrating this point. A 68-year-old man with severe chronic obstructive pulmonary disease, coronary artery disease with prior myocardial infarction, and multiple abdominal operations presented with an abdominal aortic aneurysm. In our opinion, this patient was at a prohibitive operative risk for open repair. Review of his imaging results revealed a 6.7-cm infrarenal aneurysm with bilateral common iliac artery (CIA) stents (right: 8 mm; left: 6 mm) and 6-mm self-expanding stents extending from the right external iliac artery through the common femoral artery. A Cook Zenith Renu (30 × 108 mm) graft (Cook Medical Inc., Bloomington, IN) was advanced after serial dilation and balloon angioplasty of the stenotic right CIA stent. Left brachial access was used for arteriographic imaging. The left common femoral artery was accessed and the left CIA was coil-embolized to prevent backbleeding. A femoro-femoral artery crossover bypass was then performed after segmental resection of the right common femoral artery stent. The patient tolerated the procedure well and was discharged home on postoperative day 3. Subsequent postoperative computed tomography arteriogram after 1 month showed palpable pulses and no evidence of endoleak with flow in the femoro-femoral graft on clinical exam. This case demonstrates an endovascular intervention which limited the potential options available for aneurysm repair. Similar problems may become increasingly common as more providers offer endovascular interventions, thus emphasizing the importance of a collaborative approach to the patient with complex aorto-iliac occlusive disease and abdominal aortic aneurysm. It is the duty of the

  13. Self-expanding stent-assisted middle cerebral artery recanalization: technical note

    Energy Technology Data Exchange (ETDEWEB)

    Sauvageau, Eric [State University of New York, Department of Neurosurgery, School of Medicine and Biomedical Sciences, Buffalo, NY (United States); State University of New York, Toshiba Stroke Research Center, School of Medicine and Biomedical Sciences, Buffalo, NY (United States); Levy, Elad I. [State University of New York, Department of Neurosurgery, School of Medicine and Biomedical Sciences, Buffalo, NY (United States); State University of New York, Department of Radiology, School of Medicine and Biomedical Sciences, Buffalo, NY (United States); State University of New York, Toshiba Stroke Research Center, School of Medicine and Biomedical Sciences, Buffalo, NY (United States)

    2006-06-15

    Investigation into pharmacological and mechanical means of improving recanalization rates by intraarterial therapy has led to technological development. Angiographic recanalization has been associated with improvement in clinical outcome. A clot retriever has recently joined an imperfect armamentarium for intraarterial stroke therapy. In this report, we describe successful recanalization of an acute thrombotic occlusion of the inferior division of the middle cerebral artery (MCA) achieved with a self-expanding stent. An 82-year-old woman with a history of coronary atherosclerosis and previous cerebellar hemorrhage presented with a National Institutes of Health Stroke Scale (NIHSS) score of 11. Perfusion computed tomography imaging showed a left MCA territory deficit. Diffusion-weighted magnetic resonance (MR) imaging revealed a small punctiform insular hyperintensity. Angiography documented occlusion of the inferior division of the left MCA (Thrombolysis in Myocardial Infarction or Thrombolysis in Cerebral Infarction, TIMI/TICI, grade 0). Intraarterial delivery of eptifibatide to the occlusion site failed to recanalize the vessel. Deployment of a self-expanding stent in the occluded segment resulted in complete revascularization of the distal vascular bed. Angiography performed on the next day confirmed patency of the stented vessel segment (TIMI/TICI 3). The patient was discharged 3 days after the procedure (NIHSS 3). MR angiography obtained 3 months after the procedure documented left MCA patency. This technique may have a role worthy of further investigation in acute stroke therapy. (orig.)

  14. Stent Polymers: Do They Make a Difference?

    Science.gov (United States)

    Rizas, Konstantinos D; Mehilli, Julinda

    2016-06-01

    The necessity of polymers on drug-eluting stent (DES) platforms is dictated by the need of an adequate amount and optimal release kinetic of the antiproliferative drugs for achieving ideal DES performance. However, the chronic vessel wall inflammation related to permanent polymer persistence after the drug has been eluted might trigger late restenosis and stent thrombosis. Biodegradable polymers have the potential to avoid these adverse events. A variety of biodegradable polymer DES platforms have been clinically tested, showing equal outcomes with the standard-bearer permanent polymer DES within the first year of implantation. At longer-term follow-up, promising lower rates of stent thrombosis have been observed with the early generation biodegradable polymer DES platforms compared to first-generation DES. Whether this safety benefit still persists with newer biodegradable polymer DES generations against second-generation permanent polymer DES needs to be explored. © 2016 American Heart Association, Inc.

  15. 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

  16. In vitro stent lumen visualisation of various common and newly developed femoral artery stents using MR angiography at 1.5 and 3 tesla.

    Science.gov (United States)

    Syha, R; Ketelsen, D; Kaempf, M; Mangold, S; Sixt, S; Zeller, T; Springer, F; Schick, F; Claussen, C D; Brechtel, K

    2013-02-01

    To evaluate stent lumen assessment of various commonly used and newly developed stents for the superficial femoral artery (SFA) using MR angiography (MRA) at 1.5 and 3 T. Eleven nitinol stents and one cobalt-chromium stent were compared regarding stent lumen visualisation using a common three-dimensional MRA sequence. Maximum visible stent lumen width and contrast ratio were analysed in three representative slices for each stent type. A scoring system for lumen visualisation was applied. Nitinol stents showed significantly better performance than the cobalt chromium stent (P stent lumen ranged between 43.4 and 95.5 %, contrast ratio between 7.2 and 110.6 %. Regarding both field strengths, seven of the nitinol stents were classified as "suitable". Three nitinol stents were "limited", and one nitinol stent and the cobalt chromium stent were "not suitable". Intraluminal loss of signal and artefacts of most of the SFA stents do not markedly limit assessment of stent lumen by MRA at 1.5 and 3 T. MRA can thus be considered a valid technique for detection of relevant in-stent restenosis. Applied field strength does not strongly influence stent lumen assessment in general, but proper choice of field strength might be helpful.

  17. Bridging Experience With Eptifibatide After Stent Implantation.

    Science.gov (United States)

    Barra, Megan E; Fanikos, John; Gerhard-Herman, Marie D; Bhatt, Deepak L

    2016-09-01

    Patients who have undergone intracoronary stent implantation often require surgery within the first year after the procedure. Planned or emergent surgical intervention requires interruption of antiplatelet therapy and is associated with an increased risk of stent thrombosis. Eptifibatide, an intravenous glycoprotein IIb/IIIa inhibitor (GPIIb/IIIa), can be considered for antiplatelet bridging of high-risk patients in the periprocedural period. The aim of this report is to describe the management of antiplatelet therapy and outcomes of patients who were bridged with eptifibatide perioperatively within 1 year of intracoronary stent implantation. We performed a retrospective analysis of patients identified through the hospital's computer system consecutively from January 1, 2011 to December 31, 2014. We included 18 patients who were bridged from an oral P2Y12-receptor antagonist with eptifibatide before surgery. Outcome measures were the incidence of thromboembolic events or stent thrombosis within 30 days of surgery and death within 90 days of hospital discharge. Safety measures were the incidence of thrombolysis in myocardial infarction major, minor, or minimal bleeding. Of the 18 patients assessed, no patients experienced thromboembolic events or stent thrombosis. There was one major bleeding event and one minimal bleeding event postoperatively. Antiplatelet therapy management was highly variable in the perioperative period with 72.2% receiving the recommended GPIIb/IIIa loading dose, 50% of patients not continuing aspirin throughout the surgery, 27.8% of patients stopping antiplatelet therapy less than 5 days before surgery, and 50% not receiving a loading dose of an oral P2Y12-receptor antagonist postoperatively. Within a limited sample size, bridging with an intravenous GPIIb/IIIa inhibitor appeared feasible. Further study is needed on the optimal strategy to manage patients with recent stenting who need surgical procedures.

  18. Time-related changes in neointimal tissue coverage of a novel Sirolimus eluting stent

    Energy Technology Data Exchange (ETDEWEB)

    Secco, Gioel Gabrio, E-mail: gioel.gabrio.secco@gmail.com [Interventional Cardiology, “Santi Antonio e Biagio e Cesare Arrigo” Hospital, Alessandria (Italy); NIHR Biomedical Research Unit, Royal Brompton & Harefield NHS Foundation Trust, London (United Kingdom); Mattesini, Alessio [NIHR Biomedical Research Unit, Royal Brompton & Harefield NHS Foundation Trust, London (United Kingdom); Fattori, Rossella; Parisi, Rosario [Interventional Cardiology, “San Salvatore” Hospital, Pesaro (Italy); Castriota, Fausto [GVM Care and Research, Cotignola (Italy); Vercellino, Matteo [Interventional Cardiology, “Santi Antonio e Biagio e Cesare Arrigo” Hospital, Alessandria (Italy); Dall’Ara, Gianni [NIHR Biomedical Research Unit, Royal Brompton & Harefield NHS Foundation Trust, London (United Kingdom); Uguccioni, Lucia; Marinucci, Lucia [Interventional Cardiology, “San Salvatore” Hospital, Pesaro (Italy); De Luca, Giuseppe; Marino, Paolo Nicola [University of Eastern Piedmont, Novara (Italy); Pistis, Gianfranco [Interventional Cardiology, “Santi Antonio e Biagio e Cesare Arrigo” Hospital, Alessandria (Italy); Di Mario, Carlo [NIHR Biomedical Research Unit, Royal Brompton & Harefield NHS Foundation Trust, London (United Kingdom)

    2016-01-15

    Background: DES has reduced rates of restenosis compared with BMS but it has been associated with delayed healing and increase of stent thrombosis. The aim of our study was to evaluate the vascular time-related changes following implantation of a new SES coated with an amorphous silicon carbide that allows faster re-endothelisation (Orsiro-Biotronik). Methods: This prospective registry enrolled STEMI-patients with multi-vessel disease, thus candidates for a two-step procedure. PCI of the culprit lesion was performed with at least one Orsiro stent that was OCT-analysed during the second-step procedure (deferred to 30,90 and 180-days). Results: 16 of the 95 patients with MVD underwent an OCT evaluation of the study device implanted in the culprit lesion during the second-step staged procedure and were enrolled in the present Registry. A total of 3060-struts were analysed. The percentage of uncovered struts was 19.6% at30-days, 1.3% at90-days and 1.8% at180-days (p < 0.001). The percentage of cross section with ≥ 1 uncovered struts were 51.3% at30-days, 6.5% at90-days and 5.7% at180-days (p < 0.001). The percentage of cross sections containing thrombus was 6.2% at30-days while no thrombus was detected both at90 and 180-days. Conclusions: Our data shows that the new Orsiro stent promotes early and persistent strut coverage with low peri-strut thrombus. This pilot OCT evaluation might suggest a low incidence of late adverse events and anticipate safe outcome after early withdrawal of dual antiplatelet therapy. - Highlights: • This is the first serial study comparing coverage at 1, 3, and 6-months in consecutive patients with STEMI; • Aim of our study was to evaluate the vascular time-related changes following implantation of a new SES coated with an amorphous silicon carbide that allows faster re-endothelisation (Orsiro-Biotronik); • The main finding of this pilot study is that the study device presented a fast pattern of intimal coverage, with a thin intimal

  19. Time course analysis of gene expression identifies multiple genes with differential expression in patients with in-stent restenosis

    Directory of Open Access Journals (Sweden)

    Gudnason Thorarinn

    2011-02-01

    Full Text Available Abstract Background The vascular disease in-stent restenosis (ISR is characterized by formation of neointima and adverse inward remodeling of the artery after injury by coronary stent implantation. We hypothesized that the analysis of gene expression in peripheral blood mononuclear cells (PBMCs would demonstrate differences in transcript expression between individuals who develop ISR and those who do not. Methods and Results We determined and investigated PBMC gene expression of 358 patients undergoing an index procedure to treat in de novo coronary artery lesions with bare metallic stents, using a novel time-varying intercept model to optimally assess the time course of gene expression across a time course of blood samples. Validation analyses were conducted in an independent sample of 97 patients with similar time-course blood sampling and gene expression data. We identified 47 probesets with differential expression, of which 36 were validated upon independent replication testing. The genes identified have varied functions, including some related to cellular growth and metabolism, such as the NAB2 and LAMP genes. Conclusions In a study of patients undergoing bare metallic stent implantation, we have identified and replicated differential gene expression in peripheral blood mononuclear cells, studied across a time series of blood samples. The genes identified suggest alterations in cellular growth and metabolism pathways, and these results provide the basis for further specific functional hypothesis generation and testing of the mechanisms of ISR.

  20. [Perioperative intensive statin therapy improves outcomes in patients with ischemic stroke undergoing middle cerebral artery stent implantation].

    Science.gov (United States)

    Gao, Ju-Hua; Gao, Xiao-Ping; Pan, Su-Yue

    2016-03-01

    To investigate whether intensive statin therapy during the perioperative period improves outcomes in patients undergoing middle cerebral artery (MCA) stent implantation for ischemic stroke. Forty patients with ischemic stroke undergoing delayed stent implantation in our department from January, 2010 to November, 2014 were randomized to intensive statin group (atorvastatin, 80 mg/day, 3 days before till 3 days after intervention; n=20) and standard therapy group (atorvastatin, 20 mg/day, n=20). All the patients received long-term atorvastatin treatment thereafter (20 mg/day). Serum levels of C-reactive protein (CRP), vascular cell adhesion molecule-1 (VCAM-1), and soluble extracellular matrix metalloproteinase inducer (EMMPRIN/CD147) were measured at 24 h before and 24 h after the intervention. The primary end point was procedure-related intra-stent thrombosis, 1-month incidence of major adverse cerebrovascular events (stroke, transient ischemic attack, in-stent restenosis, death or unplanned revascularization). The basic clinical data were similar between the two groups before the intervention (P>0.05). In the intensive therapy group, the levels of CRP, VCAM-1, and sCD147 were significantly lower at 24 h after the intervention than the levels before intervention (Ptherapy group (Ptherapy group (P>0.05). The incidence of primary end point was lower in intensive therapy group than in standard therapy group (Pintensive statin therapy improves the patients' outcomes, reduces the levels of CRP, VCAM-1 and sCD147 molecules, and lowers the incidences of cerebrovascular events.

  1. An in vitro study of silk stent morphology

    Energy Technology Data Exchange (ETDEWEB)

    Aurboonyawat, Thaweesak [University of Paris 7 Bichat School of Medicine, Department of Functional and Interventional Neuroradiology, Fondation Rothschild Hospital, Paris (France); Siriraj Hospital, Mahidol University, Division of Neurosurgery, Department of Surgery, Bangkok (Thailand); Blanc, Raphael; Piotin, Michel; Spelle, Laurent; Moret, Jacques [University of Paris 7 Bichat School of Medicine, Department of Functional and Interventional Neuroradiology, Fondation Rothschild Hospital, Paris (France); Schmidt, Paul [University of Paris 7 Bichat School of Medicine, Department of Functional and Interventional Neuroradiology, Fondation Rothschild Hospital, Paris (France); The Duluth Clinic Ltd, Duluth, MN (United States); Nakib, Amir [Universite de Paris 12, Laboratoire Images, Signaux et Systemes Intelligents (LISSI, E. A. 3956), Creteil (France)

    2011-09-15

    Morphology of the Silk stent (Balt, Montmorency, France) after deployment is not fully understood, especially in tortuous vessels. An in vitro study was conducted to study morphology and flow-diverting parameters of this stent. Two sets of different-sized and curved polytetrafluoroethylene tubes were studied. To simulate the aneurysm neck, a small hole was created in a tube. A stent was placed in each of the different tubes. Angiographic computerized tomography and macroscopic photography were then obtained. The images were analyzed to calculate a Percentage of Area Coverage (PAC). Good stent conformability was observed. The PAC was 21% in the straight model with matched stent and vessel diameter. In the straight model with an oversized stent, the PAC was increased. In the curved models, dynamic wire repositioning occurred. The repositioning was affected by the size of the stent and the angle of the vessel curve. Compared to the straight model, this increased the PAC in two instances: on the convexity (oversized stent), and on the concavity (matched stent and vessel diameter). The PAC did not significantly change at the sides of the curve. By design, the wires of the silk stent move relative to each other. In a curved model, the PAC is different at the convexity, concavity, and lateral walls. The stent diameter affects the PAC. These results are clinically relevant because it is desirable to maximize and minimize the PAC across the aneurysm neck and branch vessel orifice, respectively. (orig.)

  2. Optimization of stent implantation using a high pressure inflation protocol.

    Science.gov (United States)

    Vallurupalli, Srikanth; Bahia, Amit; Ruiz-Rodriguez, Ernesto; Ahmed, Zubair; Hakeem, Abdul; Uretsky, Barry F

    2016-01-01

    High-pressure inflation is the universal standard for stent deployment but a specific protocol for its use is lacking. We developed a standardized "pressure optimization protocol" (POP) using time to inflation pressure stability as an endpoint for determining the required duration of stent inflation. The primary study purpose was to determine the stent inflation time (IT) in a large patient cohort using the standardized inflation protocol, to correlate various patient and lesion characteristics with IT, and ascertain in an in vitro study the time for pressure accommodation within an inflation system. Six hundred fifteen stent implants in 435 patients were studied. Multivariate analysis was performed to determine predictors of longer ITs. In an in vitro study, various stents and balloons were inflated in air to determine the pressure accommodation time of the inflation system. The mean stent IT was 104 ± 41 sec (range 30-380 sec). Stent length was the only predictor of prolonged stent inflation. The "accommodation time" in vitro of the stent inflation system itself was 33 ± 24 sec. The protocol was safe requiring premature inflation termination in expand the stent and that the use of a pressure stability protocol will allow for safe, predictable, and more complete stent deployment. © 2015 Wiley Periodicals, Inc. © 2015 Wiley Periodicals, Inc.

  3. 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.

  4. Long-Term Results of Stenting versus Endarterectomy for Carotid-Artery Stenosis.

    Science.gov (United States)

    Brott, Thomas G; Howard, George; Roubin, Gary S; Meschia, James F; Mackey, Ariane; Brooks, William; Moore, Wesley S; Hill, Michael D; Mantese, Vito A; Clark, Wayne M; Timaran, Carlos H; Heck, Donald; Leimgruber, Pierre P; Sheffet, Alice J; Howard, Virginia J; Chaturvedi, Seemant; Lal, Brajesh K; Voeks, Jenifer H; Hobson, Robert W

    2016-03-17

    In the Carotid Revascularization Endarterectomy versus Stenting Trial, we found no significant difference between the stenting group and the endarterectomy group with respect to the primary composite end point of stroke, myocardial infarction, or death during the periprocedural period or any subsequent ipsilateral stroke during 4 years of follow-up. We now extend the results to 10 years. Among patients with carotid-artery stenosis who had been randomly assigned to stenting or endarterectomy, we evaluated outcomes every 6 months for up to 10 years at 117 centers. In addition to assessing the primary composite end point, we assessed the primary end point for the long-term extension study, which was ipsilateral stroke after the periprocedural period. Among 2502 patients, there was no significant difference in the rate of the primary composite end point between the stenting group (11.8%; 95% confidence interval [CI], 9.1 to 14.8) and the endarterectomy group (9.9%; 95% CI, 7.9 to 12.2) over 10 years of follow-up (hazard ratio, 1.10; 95% CI, 0.83 to 1.44). With respect to the primary long-term end point, postprocedural ipsilateral stroke over the 10-year follow-up occurred in 6.9% (95% CI, 4.4 to 9.7) of the patients in the stenting group and in 5.6% (95% CI, 3.7 to 7.6) of those in the endarterectomy group; the rates did not differ significantly between the groups (hazard ratio, 0.99; 95% CI, 0.64 to 1.52). No significant between-group differences with respect to either end point were detected when symptomatic patients and asymptomatic patients were analyzed separately. Over 10 years of follow-up, we did not find a significant difference between patients who underwent stenting and those who underwent endarterectomy with respect to the risk of periprocedural stroke, myocardial infarction, or death and subsequent ipsilateral stroke. The rate of postprocedural ipsilateral stroke also did not differ between groups. (Funded by the National Institutes of Health and Abbott

  5. Mesenteric artery complications during angioplasty and stent placement for atherosclerotic chronic mesenteric ischemia.

    Science.gov (United States)

    Oderich, Gustavo S; Tallarita, Tiziano; Gloviczki, Peter; Duncan, Audra A; Kalra, Manju; Misra, Sanjay; Cha, Stephen; Bower, Thomas C

    2012-04-01

    The purpose of this study was to describe the incidence, management, and outcomes of mesenteric artery complications (MACs) during angioplasty and stent placement (MAS) for chronic mesenteric ischemia (CMI). We retrospectively reviewed the clinical data of 156 patients treated with 173 MAS for CMI (1998-2010). MACs were defined as procedure-related mesenteric artery dissection, stent dislodgement, embolization, thrombosis, or perforation. End points were procedure-related morbidity and death. There were 113 women and 43 men (mean age, 73 ± 14 years). Eleven patients (7%) developed 14 MACs, including distal mesenteric embolization in six, branch perforation in three, dissection in two, stent dislodgement in two, and stent thrombosis in one. Five patients required adjunctive endovascular procedures, including in two patients each, catheter-directed thrombolysis or aspiration, retrieval of dislodged stents, and placement of additional stents for dissection. Five patients (45%) required conversion to open repair: two required evacuation of mesenteric hematoma, two required mesenteric revascularization, and one required bowel resection. There were four early deaths (2.5%) due to mesenteric embolization or myocardial infarction in two patients each. Patients with MACs had higher rates of mortality (18% vs 1.5%) and morbidity (64% vs 19%; P <.05) and a longer hospital length of stay (6.3 ± 4.2 vs 1.6 ± 1.2 days) than those without MACs. Periprocedural use of antiplatelet therapy was associated with lower risk of distal embolization or vessel thrombosis (odds ratio, 0.2; 95% confidence interval, 0.06-0.90). Patients treated by a large-profile system had a trend toward more MACs (odds ratio, 1.8; 95% confidence interval, 0.7-26.5; P = .07). MACs occurred in 7% of patients who underwent MAS for CMI and resulted in higher mortality, morbidity, and longer hospital length of stay. Use of antiplatelet therapy reduced the risk of distal embolization or vessel thrombosis. There

  6. 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.

  7. 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.)

  8. Arterial Remodeling After Bioresorbable Scaffolds and Metallic Stents.

    Science.gov (United States)

    Serruys, Patrick W; Katagiri, Yuki; Sotomi, Yohei; Zeng, Yaping; Chevalier, Bernard; van der Schaaf, René J; Baumbach, Andreas; Smits, Pieter; van Mieghem, Nicolas M; Bartorelli, Antonio; Barragan, Paul; Gershlick, Anthony; Kornowski, Ran; Macaya, Carlos; Ormiston, John; Hill, Jonathan; Lang, Irene M; Egred, Mohaned; Fajadet, Jean; Lesiak, Maciej; Windecker, Stephan; Byrne, Robert A; Räber, Lorenz; van Geuns, Robert-Jan; Mintz, Gary S; Onuma, Yoshinobu

    2017-07-04

    Although previous observational studies have documented late luminal enlargement and expansive remodeling following implantation of a bioresorbable vascular scaffold (BVS), no comparison with metallic stents has been conducted in a randomized fashion. This study sought to compare vessel remodeling patterns after either Absorb BVS or Xience metallic drug-eluting stent (DES) implantation (Abbott Vascular, Santa Clara, California) and determine the independent predictors of remodeling. In the ABSORB II randomized trial, 383 lesions (n = 359) were investigated by intravenous ultrasound both post-procedure and at 3-year follow-up. According to vessel and lumen area changes over 3 years, we categorized 9 patterns of vessel remodeling that were beyond the reproducibility of lumen and vessel area measurements. The relative change in mean vessel area was significantly greater with the BVS compared to the DES (6.7 ± 12.6% vs. 2.9 ± 11.5%; p = 0.003); the relative change in mean lumen area was significantly different between the 2 arms (1.4 ± 19.1% vs. -1.9 ± 10.5%, respectively; p = 0.031). Multivariate analysis indicated that use of the BVS, female sex, balloon-artery ratio >1.25, expansion index ≥0.8, previous percutaneous coronary intervention, and higher level of low-density lipoprotein cholesterol were independent predictors of expansive remodeling. Furthermore, in the BVS arm, necrotic core pre-procedure was an independent determinant of expansive remodeling. Expansive vessel wall remodeling was more frequent and intense with the BVS than the metallic DES and could be determined by patient baseline characteristics and periprocedural factors. The clinical effect of the observed lumen and vessel remodeling must be investigated in further large clinical studies to optimize the clinical outcome of patients and lesions treated by bioresorbable scaffolds. (ABSORB II Randomized Controlled Trial; NCT01425281). Copyright © 2017 American College of Cardiology

  9. A prospective randomized trial comparing endarterectomy to stenting in severe asymptomatic carotid stenosis.

    Science.gov (United States)

    Mannheim, Dallit; Karmeli, Ron

    2017-12-01

    For an asymptomatic patient with severe carotid stenosis the most important question is how to prevent an ischemic stroke. Carotid artery stenosis is the estimated cause of stroke in 8-20% of the cases. Today more than 50% of procedures for carotid stenosis are done on asymptomatic patients, but few of the randomized controlled trials comparing carotid endarterectomy and stenting examined specifically these patients. All patients with severe (>70%) asymptomatic carotid artery stenosis seen in the Carmel medical center vascular clinic were prospectively screened and randomized 1:1 for carotid endarterectomy (CEA) or carotid stenting (CAS). Patients eligible for both procedures were enrolled. The primary objectives of the study were: 1) periprocedural complications - stroke (CVA), transient ischemic attack (TIA), myocardial infarction (MI), and death; 2) long-term results: mortality, prevention of ipsilateral stroke or TIA, and freedom from restenosis. One-hundred and thirty-six patients were treated with mean follow-up of 26 months. There was no difference in short and long term results between the two groups. Thirty day morbidity included: 1 CVA in each group with no MI. Long-term results included 4 deaths in each group; none from CVA. One TIA was noted after CAS, and 3 cases of restenosis were found in CEA and one in CAS. CAS is a maturing procedure and has improved significantly over the past several years. Future developments of stents and protection devices will achieve better perioperative results. This along with our excellent long term results will promote the use of stenting for suitable patients.

  10. Hemocompatibility Improvement of Chromium-Bearing Bare-Metal Stent Platform After Magnetoelectropolishing

    Science.gov (United States)

    Rokicki, Ryszard; Haider, Waseem; Maffi, Shivani Kaushal

    2015-01-01

    Research was undertaken to determine the influence of the increased content of chromium in the outermost passive layer of magneto-electrochemically refined Co-Cr alloy L-605 surface on its hemocompatibility. The chemistry, roughness, surface energy, and wettability of conventionally electropolished (EP) and magnetoelectropolished (MEP) samples were studied with x-ray photoelectron spectroscopy (XPS), open circuit potential, atomic force microscopy, and contact angle meter. In vitro hemocompatibility of tested material surfaces was assessed using two important indicators of vascular responses to biomaterial, namely endothelialization and platelets adhesion. The endothelialization was assessed by seeding and incubating samples with human umbilical vein endothelial cells (HUVEC) for 3 days before counting and observing them under a fluorescent microscope. The platelet (rich plasma blood) adhesion and activation test on EP and MEP L-605 alloy surfaces was assessed using a laser scanning confocal microscope. The XPS analysis of MEP samples showed significant enrichment of the passive layer with Cr and O when compared with the EP one. The amount of other elements in the passive layer did not show a significant difference between EP and MEP treatments. The adhesion of HUVEC cells shows remarkable affinity to surfaces enriched in Cr (MEP) with almost 100% confluency. In addition, the number of platelets that adhered to standard EP surfaces was higher compared to the MEP surface. The present study shows that the chromium-enriched surface of cobalt-chromium alloy L-605 by the magnetoelectropolishing process tremendously improves surface hemocompatibility with regard to stent functionality by enhanced endothelialization and lower platelet adhesion and should be taken under consideration as an alternative surface of biodegradable polymer drug-eluting stents, polymer-free drug-eluting stents as well as bare-metal stents.

  11. Flow Characteristics Near to Stent Strut Configurations on Femoropopliteal Artery

    Science.gov (United States)

    Paisal, Muhammad Sufyan Amir; Fadhil Syed Adnan, Syed; Taib, Ishkrizat; Ismail, Al Emran; Kamil Abdullah, Mohammad; Nordin, Normayati; Seri, Suzairin Md; Darlis, Nofrizalidris

    2017-08-01

    Femoropopiteal artery stenting is a common procedure suggested by medical expert especially for patient who is diagnosed with severe stenosis. Many researchers reported that the growth of stenosis is significantly related to the geometry of stent strut configuration. The different shapes of stent geometry are presenting the different flow pattern and re-circulation in stented femoropopliteal artery. The blood flow characteristics near to the stent geometry are predicted for the possibility of thrombosis and atherosclerosis to be formed as well as increase the growth of stenosis. Thus, this study aims to determine the flow characteristic near to stent strut configuration based on different hemodynamic parameters. Three dimensional models of stent and simplified femoropopliteal artery are modelled using computer aided design (CAD) software. Three different models of stent shapes; hexagon, circle and rectangle are simulated using computational fluid dynamic (CFD) method. Then, parametric study is implemented to predict the performance of stent due to hemodynamic differences. The hemodynamic parameters considered are pressure, velocity, low wall shear stress (WSSlow) and wall shear stress (WSS). From the observation, flow re-circulation has been formed for all simulated stent models which the proximal region shown the severe vortices. However, rectangular shape of stent strut (Type P3) shows the lowest WSSlow and the highest WSS between the range of 4 dyne/cm2 and 70 dyne/cm2. Stent Type P3 also shows the best hemodynamic stent performance as compare to others. In conclusion, Type P3 has a favourable result in hemodynamic stent performance that predicted less probability of thrombosis and atherosclerosis to be formed as well as reduces the growth of restenosis.

  12. Cyclodextrins in Asymmetric and Stereospecific Synthesis

    Directory of Open Access Journals (Sweden)

    Fliur Macaev

    2015-09-01

    Full Text Available Since their discovery, cyclodextrins have widely been used as green and easily available alternatives to promoters or catalysts of different chemical reactions in water. This review covers the research and application of cyclodextrins and their derivatives in asymmetric and stereospecific syntheses, with their division into three main groups: (1 cyclodextrins promoting asymmetric and stereospecific catalysis in water; (2 cyclodextrins’ complexes with transition metals as asymmetric and stereospecific catalysts; and (3 cyclodextrins’ non-metallic derivatives as asymmetric and stereospecific catalysts. The scope of this review is to systematize existing information on the contribution of cyclodextrins to asymmetric and stereospecific synthesis and, thus, to facilitate further development in this direction.

  13. A Note on Asymmetric Thick Branes

    Directory of Open Access Journals (Sweden)

    D. Bazeia

    2014-01-01

    Full Text Available We study asymmetric thick braneworld scenarios, generated after adding a constant to the superpotential associated with the scalar field. We study in particular models with odd and even polynomial superpotentials, and we show that asymmetric brane can be generated irrespective of the potential being symmetric or asymmetric. We study in addition the nonpolynomial sine-Gordon like model, also constructed with the inclusion of a constant in the standard superpotential, and we investigate gravitational stability of the asymmetric brane. The results suggest robustness of the new braneworld scenarios and add further possibilities of the construction of asymmetric branes.

  14. Comparison of thin-strut cobalt-chromium stents and stainless steel stents in a porcine model of neointimal hyperplasia.

    Science.gov (United States)

    Milewski, Krzysztof; Zurakowski, Aleksander; Pajak, Jacek; Pajak-Zielinska, Ewa; Liszka, Lukasz; Buszman, Piotr P; Bis, Jaroslaw; Debinski, Marcin; Buszman, Pawel E

    2010-01-01

    The high radial force and durability of cobalt-chromium alloy enable the construction of low-profile stents with thin struts, which improves their elasticity and may play a key role in reducing the incidence of neointimal hyperplasia as well as allow faster endothelialization. The aim of this study was to compare cobalt-chromium (CoCr) and stainless steel (SS) coronary stents in a pig model of neointimal hyperplasia. Eighteen stents were implanted into the coronary arteries of nine pigs. Control coronarography was performed 28 days after stent implantation. The animals were then sacrificed, their hearts explanted, and the coronary arteries isolated for further histopathological analysis. Quantitative coronary angiography and histomorphometric analysis revealed no statistically significant difference between the two groups of stents. However, there was a trend toward greater late lumen loss (p=0.09) and neointimal area in the CoCr stents (p=0.08). The qualitative histopathology of the CoCr stents revealed findings typical of bare metal stents reviewed in the literature and approved for use in clinical practice. No signs of stent thrombosis, necrosis, or fibrin deposits were observed nor signs of excessive inflammatory reaction. Endothelialization was complete within 28 days. Despite thinner struts, CoCr stents have no advantage over stainless steel stents in terms of neointimal hyperplasia inhibition. However, their positive safety results together with their high radial strength, low profile, and excellent elasticity can ensure their usage, especially in lesions of complex morphology.

  15. Plant Vascular Biology 2013: vascular trafficking.

    Science.gov (United States)

    Ursache, Robertas; Heo, Jung-Ok; Helariutta, Ykä

    2014-04-01

    About 200 researchers from around the world attended the Third International Conference on Plant Vascular Biology (PVB 2013) held in July 2013 at the Rantapuisto Conference Center, in Helsinki, Finland (http://www.pvb2013.org). The plant vascular system, which connects every organ in the mature plant, continues to attract the interest of researchers representing a wide range of disciplines, including development, physiology, systems biology, and computational biology. At the meeting, participants discussed the latest research advances in vascular development, long- and short-distance vascular transport and long-distance signalling in plant defence, in addition to providing a context for how these studies intersect with each other. The meeting provided an opportunity for researchers working across a broad range of fields to share ideas and to discuss future directions in the expanding field of vascular biology. In this report, the latest advances in understanding the mechanism of vascular trafficking presented at the meeting have been summarized.

  16. Stent thrombosis after coronary stent implantation: a protective effect of high-dose statin therapy?

    Science.gov (United States)

    Jeger, Raban V; Brunner-La Rocca, Hans Peter; Bertel, Osmund; Kiowski, Wolfgang; Pfisterer, Matthias E; Kaiser, Christoph A

    2013-01-01

    To assess independent predictors of stent thrombosis (ST) in an all-comer trial. This is an observational case-control study based on a retrospective analysis of the Basel Stent Kosten Effektivitäts Trial (BASKET) (n = 826). Patients with ST were compared to controls with regard to baseline parameters. Multivariate models were performed to identify independent predictors of ST. At 36 months, there were 53 (6.4%) patients with ST, 17 (32%) of whom had early ST and 36 (68%) of whom had late/very late ST. Patients with ST were at a higher cardiovascular risk but received lower doses of statins than the controls (n = 212). Stents in ST patients were longer, had more overlap and were not as well expanded, with significantly more remaining stenoses than the stents in the controls. Multivariable analysis revealed interventions in saphenous vein grafts, malapposed stents, an overlap >3 mm, complex coronary anatomy and treatment with low-dose/no statins as risk factors for ST, while interventions in saphenous vein grafts, underexpanded or malapposed stents, a history of myocardial infarction and treatment with low-dose/no statins were risk factors for late ST. The use of statins might have a protective effect against ST. This observation is new, hypothesis-generating and should be evaluated in an adequately powered randomized trial. Copyright © 2013 S. Karger AG, Basel.

  17. Two-year clinical, angiographic, and serial optical coherence tomographic follow-up after implantation of an everolimus-eluting bioresorbable scaffold and an everolimus-eluting metallic stent: insights from the randomised ABSORB Japan trial

    NARCIS (Netherlands)

    Onuma, Yoshinobu; Sotomi, Yohei; Shiomi, Hiroki; Ozaki, Yukio; Namiki, Atsuro; Yasuda, Satoshi; Ueno, Takafumi; Ando, Kenji; Furuya, Jungo; Igarashi, Keiichi; Kozuma, Ken; Tanabe, Kengo; Kusano, Hajime; Rapoza, Richard; Popma, Jeffrey J.; Stone, Gregg W.; Simonton, Charles; Serruys, Patrick W.; Kimura, Takeshi

    2016-01-01

    We sought to investigate two-year clinical and serial optical coherence tomography (OCT) outcomes after implantation of a fully bioresorbable vascular scaffold (BVS) or a cobalt-chromium everolimus-eluting stent (CoCr-EES). In the ABSORB Japan trial, 400 patients were randomised in a 2:1 ratio to

  18. Geodesics in Asymmetric Metric Spaces

    Directory of Open Access Journals (Sweden)

    Mennucci Andrea C. G.

    2014-01-01

    Full Text Available In a recent paper [17] we studied asymmetric metric spaces; in this context we studied the length of paths, introduced the class of run-continuous paths; and noted that there are different definitions of “length spaces” (also known as “path-metric spaces” or “intrinsic spaces”. In this paper we continue the analysis of asymmetric metric spaces.We propose possible definitions of completeness and (local compactness.We define the geodesics using as admissible paths the class of run-continuous paths.We define midpoints, convexity, and quasi-midpoints, but without assuming the space be intrinsic.We distinguish all along those results that need a stronger separation hypothesis. Eventually we discuss how the newly developed theory impacts the most important results, such as the existence of geodesics, and the renowned Hopf-Rinow (or Cohn-Vossen theorem.

  19. Electron Jet of Asymmetric Reconnection

    Science.gov (United States)

    Khotyaintsev, Yu. V.; Graham, D. B.; Norgren, C.; Eriksson, E.; Li, W.; Johlander, A.; Vaivads, A.; Andre, M.; Pritchett, P. L.; Retino, A.; hide

    2016-01-01

    We present Magnetospheric Multiscale observations of an electron-scale current sheet and electron outflow jet for asymmetric reconnection with guide field at the subsolar magnetopause. The electron jet observed within the reconnection region has an electron Mach number of 0.35 and is associated with electron agyrotropy. The jet is unstable to an electrostatic instability which generates intense waves with E(sub parallel lines) amplitudes reaching up to 300 mV/m and potentials up to 20% of the electron thermal energy. We see evidence of interaction between the waves and the electron beam, leading to quick thermalization of the beam and stabilization of the instability. The wave phase speed is comparable to the ion thermal speed, suggesting that the instability is of Buneman type, and therefore introduces electron-ion drag and leads to braking of the electron flow. Our observations demonstrate that electrostatic turbulence plays an important role in the electron-scale physics of asymmetric reconnection.

  20. Bioprinting for vascular and vascularized tissue biofabrication.

    Science.gov (United States)

    Datta, Pallab; Ayan, Bugra; Ozbolat, Ibrahim T

    2017-03-15

    Bioprinting is a promising technology to fabricate design-specific tissue constructs due to its ability to create complex, heterocellular structures with anatomical precision. Bioprinting enables the deposition of various biologics including growth factors, cells, genes, neo-tissues and extra-cellular matrix-like hydrogels. Benefits of bioprinting have started to make a mark in the fields of tissue engineering, regenerative medicine and pharmaceutics. Specifically, in the field of tissue engineering, the creation of vascularized tissue constructs has remained a principal challenge till date. However, given the myriad advantages over other biofabrication methods, it becomes organic to expect that bioprinting can provide a viable solution for the vascularization problem, and facilitate the clinical translation of tissue engineered constructs. This article provides a comprehensive account of bioprinting of vascular and vascularized tissue constructs. The review is structured as introducing the scope of bioprinting in tissue engineering applications, key vascular anatomical features and then a thorough coverage of 3D bioprinting using extrusion-, droplet- and laser-based bioprinting for fabrication of vascular tissue constructs. The review then provides the reader with the use of bioprinting for obtaining thick vascularized tissues using sacrificial bioink materials. Current challenges are discussed, a comparative evaluation of different bioprinting modalities is presented and future prospects are provided to the reader. Biofabrication of living tissues and organs at the clinically-relevant volumes vitally depends on the integration of vascular network. Despite the great progress in traditional biofabrication approaches, building perfusable hierarchical vascular network is a major challenge. Bioprinting is an emerging technology to fabricate design-specific tissue constructs due to its ability to create complex, heterocellular structures with anatomical precision

  1. Asymmetric information and macroeconomic dynamics

    Science.gov (United States)

    Hawkins, Raymond J.; Aoki, Masanao; Roy Frieden, B.

    2010-09-01

    We show how macroeconomic dynamics can be derived from asymmetric information. As an illustration of the utility of this approach we derive the equilibrium density, non-equilibrium densities and the equation of motion for the response to a demand shock for productivity in a simple economy. Novel consequences of this approach include a natural incorporation of time dependence into macroeconomics and a common information-theoretic basis for economics and other fields seeking to link micro-dynamics and macro-observables.

  2. Comprehensive asymmetric dark matter model

    OpenAIRE

    Lonsdale, Stephen J.; Volkas, Raymond R.

    2018-01-01

    Asymmetric dark matter (ADM) is motivated by the similar cosmological mass densities measured for ordinary and dark matter. We present a comprehensive theory for ADM that addresses the mass density similarity, going beyond the usual ADM explanations of similar number densities. It features an explicit matter-antimatter asymmetry generation mechanism, has one fully worked out thermal history and suggestions for other possibilities, and meets all phenomenological, cosmological and astrophysical...

  3. Improvement of Stent Retriever Design and Efficacy of Mechanical Thrombectomy in a Flow Model

    Energy Technology Data Exchange (ETDEWEB)

    Wenger, Katharina, E-mail: kwenger@stud.uni-frankfurt.de [Institute of Neuroradiology, University of Frankfurt am Main (Germany); Nagl, Frank, E-mail: fnagl@acandis.com [Acandis GmbH and Co KG (Germany); Wagner, Marlies, E-mail: Marlies.Wagner@kgu.de; Berkefeld, Joachim, E-mail: berkefeld@em.uni-frankfurt.de [Institute of Neuroradiology, University of Frankfurt am Main (Germany)

    2013-02-15

    In vitro experiments were performed to evaluate the efficacy of mechanical intracranial thrombectomy comparing the newly developed Aperio stent retriever and standard devices for stroke treatment. The Aperio (A), with an increased working length of 4 cm and a special cell design for capturing and withholding clots, was compared to three benchmark devices: the Solitaire retrievable stent (B), the Merci X6 (C), and the Merci L5 retriever (D). In a vascular glass model with pulsatile flow, reminiscent of the M1 segment of the middle cerebral artery, we repeatedly induced occlusion by generating thrombi via a modified Chandler loop system. The numbers of recanalization attempts, peripheral embolizations, and recanalizations at the site of occlusion were recorded during 10 retrieval experiments with each device. Eleven devices were able to remove the blood clots from the occluded branch. In 34 of 40 experiments, restoration of flow was obtained in 1-3 attempts. The main differences between the study devices were observed in terms of clot withholding and fragmentation during retrieval. Although there was only one fragmentation recorded for device A, disengagement of the whole clot or peripheral embolization of fragments occurred more frequently (5-7 times) with devices B, C, and D. In a vascular model, the design of device A was best at capturing and withholding thrombi during retrieval. Further study will be necessary to see whether this holds true in clinical applications.

  4. Sutureless microvascular anastomosis assisted by an expandable shape-memory alloy stent.

    Science.gov (United States)

    Saegusa, Noriko; Sarukawa, Shunji; Ohta, Kunihiro; Takamatsu, Kensuke; Watanabe, Mitsuhiro; Sugino, Takashi; Nakagawa, Masahiro; Akiyama, Yasuto; Kusuhara, Masatoshi; Kishi, Kazuo; Inoue, Keita

    2017-01-01

    Vascular anastomosis is the highlight of cardiovascular, transplant, and reconstructive surgery, which has long been performed by hand using a needle and suture. However, anastomotic thrombosis occurs in approximately 0.5-10% of cases, which can cause serious complications. To improve the surgical outcomes, attempts to develop devices for vascular anastomosis have been made, but they have had limitations in handling, cost, patency rate, and strength at the anastomotic site. Recently, indwelling metal stents have been greatly improved with precise laser metalwork through programming technology. In the present study, we designed a bare metal stent, Microstent, that was constructed by laser machining of a shape-memory alloy, NiTi. An end-to-end microvascular anastomosis was performed in SD rats by placing the Microstent at the anastomotic site and gluing the junction. The operation time for the anastomosis was significantly shortened using Microstent. Thrombus formation, patency rate, and blood vessel strength in the Microstent anastomosis were superior or comparable to hand-sewn anastomosis. The results demonstrated the safety and effectiveness, as well as the operability, of the new method, suggesting its great benefit for surgeons by simplifying the technique for microvascular anastomosis.

  5. Augmentation of in-stent clot dissolution by low frequency ultrasound combined with aspirin and heparin. An ex-vivo canine shunt study.

    Science.gov (United States)

    Neuman, Yoram; Rukshin, Vladimir; Tsang, Vivian; Atar, Shaul; Miyamoto, Takashi; Luo, Huai; Kobal, Sergio; Thompson, Todd; Birnbaum, Yochai; Horzewski, Mike; Siegel, Robert J; Kaul, Sanjay

    2003-01-01

    Ultrasound can accelerate clot dissolution in vitro and in vivo. We used an ex vivo canine shunt to investigate low frequency ultrasound effects on platelet-rich stent thrombosis. Nitinol stents were expanded to 2 mm in diameter in two perfusion chambers in a parallel shunt and exposed to flowing arterial blood at 2100 s(-1) to generate stent thrombi (n=224 perfusion runs). Dethrombotic effects were assessed during treatment with saline and combined treatment with aspirin and heparin. One stent was exposed to ultrasound (27 kHz, 1.4 W/cm2), while the other was not. Stent thrombi were weighed before and after treatment. There was no significant effect of ultrasound during saline infusion. Treatment with aspirin+heparin alone reduced thrombus weight by 37+/-25% (18.9+/-6.1 to 11.8+/-7.7 mg, pthrombi. These findings suggest the potential of ultrasound as an adjunct to antithrombotic therapy to improve effectiveness without increasing the risk of bleeding complications during treatment of vascular thrombosis.

  6. Combined stent placement and high dose PGE1 drip infusion for chronic occlusion of the superficial femoral artery as a modality to salvage chronic critical limb ischemia

    Energy Technology Data Exchange (ETDEWEB)

    Ikushima, Ichiro [Department of Radiology, Miyakonojo Medical Association Hospital, 5822-3 Oiwadacho, Miyakonojo 885-0062 (Japan)], E-mail: iku-i@fk.enjoy.ne.jp; Hirai, Toshinori [Department of Diagnostic Radiology, Graduate School of Medical Sciences, Kumamoto University (Japan); Ishii, Akihiko [Department of Radiology, Miyakonojo Medical Association Hospital, 5822-3 Oiwadacho, Miyakonojo 885-0062 (Japan); Yamashita, Yasuyuki [Department of Diagnostic Radiology, Graduate School of Medical Sciences, Kumamoto University (Japan)

    2008-04-15

    Purpose: To assess the initial effect, short-term patency, and limb salvage rates of combined stent placement and high-dose prostaglandin E-1 (PGE1) drip infusion for chronic occlusion of the superficial femoral artery (SFA). Materials and methods: A total of 15 arteriosclerotic occlusive lesions of the SFA were treated in 11 consecutive patients (mean age: 78.4 years old). All cases were of category 4 or 5, based on the criteria of the Society of Vascular Surgery and Intermittent Society for Cardiovascular Surgery (SVC/ISCVS). In all cases a self-expandable stainless steel stent was implanted. PGE1 treatment was started 3-5 days before stent placement and continued for 7-10 days after the intervention. The technical success, limb salvage outcomes, patency rates, and complications were examined. Results: In all cases, the technical success rate of the procedure was 100%. After stent implantation, the clinical status of all cases was improved by at least +2, and major amputation was not required in any cases. The 12-month primary, secondary patency rates, and limb salvage rate were 57%, 100%, and 100%, respectively. Conclusion: Combined stent placement and high-dose PGE1 drip infusion is a treatment of choice for salvaging the lower limb of a patient with chronic critical ischemia.

  7. Up-down asymmetric tokamaks

    CERN Document Server

    Ball, Justin

    2016-01-01

    Bulk toroidal rotation has proven capable of stabilising both dangerous MHD modes and turbulence. In this thesis, we explore a method to drive rotation in large tokamaks: up-down asymmetry in the magnetic equilibrium. We seek to maximise this rotation by finding optimal up-down asymmetric flux surface shapes. First, we use the ideal MHD model to show that low order external shaping (e.g. elongation) is best for creating up-down asymmetric flux surfaces throughout the device. Then, we calculate realistic up-down asymmetric equilibria for input into nonlinear gyrokinetic turbulence analysis. Analytic gyrokinetics shows that, in the limit of fast shaping effects, a poloidal tilt of the flux surface shaping has little effect on turbulent transport. Since up-down symmetric surfaces do not transport momentum, this invariance to tilt implies that devices with mirror symmetry about any line in the poloidal plane will drive minimal rotation. Accordingly, further analytic investigation suggests that non-mirror symmetri...

  8. Vessel wall reactions to endovascular stent implantation

    NARCIS (Netherlands)

    H.M.M. van Beusekom (Heleen)

    1993-01-01

    textabstractIn order to gain insight in the effects of stenting, we studied the process of wound healing and the short- and long-term effect of these permanently present foreign bodies. Both thrombogenic and less thrombogenic metals were evaluated with respect to thrombogenicity and tissue response.

  9. Carotid artery stenting : a 2009 update

    NARCIS (Netherlands)

    Zeebregts, Clark J.; Meerwaldt, Robbert; Geelkerken, Robert H.

    2009-01-01

    Purpose of review Carotid endarterectomy (CEA) is is still considered the gold standard in the treatment of patients with significant carotid stenosis and has proven its value over the past decades. Endovascular techniques have evolved, and carotid artery stenting (CAS) is challenging CEA to become

  10. Oesophageal cancer and experience with endoscopic stent ...

    African Journals Online (AJOL)

    Background: Oesophageal cancer often presents in advanced stages not amenable to surgical resection. In such patients, palliation of dysphagia remains the mainstay of management. Objectives: To determine the burden of advanced oesophageal cancer and to document the experience with endoscopic metal stent ...

  11. Circadian Variation in Coronary Stent Thrombosis

    NARCIS (Netherlands)

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

    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

  12. Angioplasty and stent placement - carotid artery - discharge

    Science.gov (United States)

    ... E, eds. Braunwald's Heart Disease: A Textbook of Cardiovascular Medicine . 10th ed. Philadelphia, PA: Elsevier Saunders; 2015:chap 60. Read More Carotid artery disease Carotid artery surgery Recovering after stroke Risks of tobacco Smoking - tips on how to quit Stent Stroke ...

  13. 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.)

  14. Oesophageal cancer and experience with endoscopic stent ...

    African Journals Online (AJOL)

    Background: Oesophageal cancer often presents in advanced stages not amenable to surgical resection. In such patients, palliation of dysphagia remains the mainstay of management. oBjectives: To determine the burden of advanced oesophageal cancer and to document the experience with endoscopic metal stent.

  15. Restenosis begets restenosis : implications for stent selection

    NARCIS (Netherlands)

    Wijpkema, J. S.; Anthonio, R. L.; Jessurun, G. A. J.; Dijk, W. A.; Tio, R. A.; Zijlstra, F.

    2008-01-01

    Background: Identifying the risk for restenosis is of critical importance in the stent selection process of patients undergoing percutaneous coronary intervention (PCI). Therefore, we sought to determine if a history of clinical recurrence (CR) after PCI increases the risk of CR after treatment of a

  16. Oesphageal Stenting for palliation of malignant mesothelioma

    Directory of Open Access Journals (Sweden)

    Rahamim Joseph

    2008-01-01

    Full Text Available Abstract Dyspahgia in patients with malignant mesothelioma is usually due to direct infiltration of the eosophagus by the tumour. It can be distressing for the patient and challenging for the physician to treat. We describe three cases in which this condition has been successfully palliated with self expanding esophageal stents.

  17. Percutaneous extraction of stented device leads.

    Science.gov (United States)

    Baranowski, Bryan; Wazni, Oussama; Chung, Roy; Martin, David O; Rickard, John; Tanaka-Esposito, Christine; Bassiouny, Mohammed; Wilkoff, Bruce L

    2012-05-01

    There are limited published data regarding the percutaneous extraction of device leads jailed by a venous stent. In this study we assessed the feasibility and safety of percutaneous extraction of stented device leads. We reviewed our experience percutaneously extracting 7 chronically implanted device leads jailed to the wall of the left innominate and/or subclavian veins by a previously placed stent. All leads were successfully extracted by using a percutaneous approach. Both pacing leads and defibrillator leads were extracted. The oldest pacing lead extracted was 14 years old. The oldest defibrillator lead extracted was 6 years old. Three of the leads were extracted with simple manual traction alone. The 4 remaining leads required a more complex, femoral extraction approach for successful removal. In our experience extracting 7 stented device leads, complete percutaneous removal was feasible 100% of the time using a combination of simple manual traction and a femoral approach. No major complications were associated with the extraction procedures. Copyright © 2012 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.

  18. Iatrogenic Vascular Injuries Due to Spinal Surgeries: Endovascular Perspective.

    Science.gov (United States)

    Gok, Mustafa; Aydin, Elcin; Guneyli, Serkan; Akay, Ali; Cinar, Celal; Oran, Ismail

    2017-01-17

    Iatrogenic vascular injuries due to spinal surgeries are rare but serious complications. Surgical management of these injuries is challenging with high morbidity rates. In this study we aim to present the results of endovascular management of iatrogenic vascular injuries due to spinal surgeries. We retrospectively reviewed 11 patients (5 male, 6 female) who had vascular injuries due to cervical and lumbar spinal surgeries. Clinical findings were bleeding (n=5), leg edema (n=6) and right heart failure with severe dyspnea (n=1). The age range of the patients were between 42-67 (mean: 57.1). Six patients were reviewed with imaging before the procedures and the rest of the patients (n=5) were directly referred to the angiography unit for diagnosis and possible endovascular treatment. The types of surgeries were; cervical surgery (n=5) and lumbar disc operation (n=6). The type of vascular injuries were; vertebral artery stenosis (n=1), vertebral artery pseudoaneurysm (n=3), vertebral artery occlusion (n=1) and iliac arteriovenous fistula (n=6). The type of endovascular treatments were; parent artery occlusion (PAO) (n=2), covered stent graft implantation (n=6) and intrasaccular coil embolization of pseudoaneurysm (n=1). The remaining 2 patients were managed conservatively. No major complications or mortality occured during endovascular interventions. No bleeding or ischemia occured in the follow-up period. Iatrogenic vascular injuries due to spinal surgeries are rare but serious complications. Endovascular interventions are safe and effective in the diagnosis and treatment of such vascular injuries.

  19. Vascular anatomy in children with univentricular hearts regarding transcatheter bidirectional Glenn anastomosis.

    Science.gov (United States)

    Sizarov, Aleksander; Raimondi, Francesca; Bonnet, Damien; Boudjemline, Younes

    2017-04-01

    Transcatheter stent-secured Glenn anastomosis, aiming to reduce the invasiveness of palliation in patients with univentricular heart defects, has been reported in large experimental animals. The advent of biodegradable stents and tissue-engineered vascular grafts will make this procedure a reality in human patients. However, the relationship between the superior vena cava (SVC) and the right pulmonary artery (RPA) is different in humans. To characterise vascular anatomy in children with univentricular hearts, regarding technical aspects and device design for this procedure. Retrospective analysis of 35 thoracic computed tomography angiograms at a mean age of 18.1±22.4 months. Two types of arrangement between the SVC and the RPA were identified: anatomy convenient for immediate wire passage and stent deployment between the two vessels (60%); and pattern of early RPA branching, requiring the perforation wire to traverse the intervascular space to avoid entrance into the upper RPA branch (40%). In patients with the convenient vascular arrangement, the vessels were nearly perpendicular, having immediate contact, with the posterior SVC aspect partially "wrapping" the adjacent RPA in most patients. In patients with early RPA branching, the mean shortest SVC-to-central RPA distance was 4.3±2.7mm. For the total population, the mean length of proximal SVC that allowed stent deployment without covering the brachiocephalic vein was 15.6±5.1mm. A trumpet-shaped covered stent in a craniocaudal orientation reaching from the SVC into the prebranching RPA seems most suitable for achieving bidirectional Glenn anastomosis percutaneously in humans. However, the short length of the proximal SVC and the presence of early RPA branching pose challenges for optimal design of the dedicated device. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  20. Computational design analysis for deployment of cardiovascular stents

    Science.gov (United States)

    Tammareddi, Sriram; Sun, Guangyong; Li, Qing

    2010-06-01

    Cardiovascular disease has become a major global healthcare problem. As one of the relatively new medical devices, stents offer a minimally-invasive surgical strategy to improve the quality of life for numerous cardiovascular disease patients. One of the key associative issues has been to understand the effect of stent structures on its deployment behaviour. This paper aims to develop a computational model for exploring the biomechanical responses to the change in stent geometrical parameters, namely the strut thickness and cross-link width of the Palmaz-Schatz stent. Explicit 3D dynamic finite element analysis was carried out to explore the sensitivity of these geometrical parameters on deployment performance, such as dog-boning, fore-shortening, and stent deformation over the load cycle. It has been found that an increase in stent thickness causes a sizeable rise in the load required to deform the stent to its target diameter, whilst reducing maximum dog-boning in the stent. An increase in the cross-link width showed that no change in the load is required to deform the stent to its target diameter, and there is no apparent correlation with dog-boning but an increased fore-shortening with increasing cross-link width. The computational modelling and analysis presented herein proves an effective way to refine or optimise the design of stent structures.

  1. Design Investigation on Applicable Mesh Structures for Medical Stent Applications

    Science.gov (United States)

    Asano, Shoji; He, Jianmei

    2017-11-01

    In recent years, utilization of medical stents is one of effective treatments for stenosis and occlusion occurring in a living body’s lumen indispensable for maintenance of human life such as superficial femoral artery (SFA) occlusion. However, there are concerns about the occurrence of fatigue fractures caused by stress concentrations, neointimal hyperplasia and the like due to the shape structure and the manufacturing method in the conventional stents, and a stent having high strength and high flexibility is required. Therefore, in this research, applicable mesh structures for medical stents based on the design concepts of high strength, high flexibility are interested to solve various problem of conventional stent. According to the shape and dimensions of SFA occlusion therapy stent and indwelling delivery catheter, shape design of the meshed stent are performed using 3-dimensional CAD software Solid Works first. Then analytical examination on storage characteristics and compression characteristics of such mesh structure applied stent models were carried out through finite element analysis software ANSYS Workbench. Meshed stent models with higher strength and higher flexibility with integral molding are investigated analytically. It was found that the storage characteristics and compression characteristics of meshed stent modles are highly dependent on the basic mesh shapes with same surface void ratio. Trade-off relationship between flexibility and storage characteristics is found exited, it is required to provide appropriate curvatures during basic mesh shape design.

  2. Stents: Biomechanics, Biomaterials, and Insights from Computational Modeling.

    Science.gov (United States)

    Karanasiou, Georgia S; Papafaklis, Michail I; Conway, Claire; Michalis, Lampros K; Tzafriri, Rami; Edelman, Elazer R; Fotiadis, Dimitrios I

    2017-04-01

    Coronary stents have revolutionized the treatment of coronary artery disease. Improvement in clinical outcomes requires detailed evaluation of the performance of stent biomechanics and the effectiveness as well as safety of biomaterials aiming at optimization of endovascular devices. Stents need to harmonize the hemodynamic environment and promote beneficial vessel healing processes with decreased thrombogenicity. Stent design variables and expansion properties are critical for vessel scaffolding. Drug-elution from stents, can help inhibit in-stent restenosis, but adds further complexity as drug release kinetics and coating formulations can dominate tissue responses. Biodegradable and bioabsorbable stents go one step further providing complete absorption over time governed by corrosion and erosion mechanisms. The advances in computing power and computational methods have enabled the application of numerical simulations and the in silico evaluation of the performance of stent devices made up of complex alloys and bioerodible materials in a range of dimensions and designs and with the capacity to retain and elute bioactive agents. This review presents the current knowledge on stent biomechanics, stent fatigue as well as drug release and mechanisms governing biodegradability focusing on the insights from computational modeling approaches.

  3. A retrievable nitinol endobronchial stent : an experimental study in dog

    Energy Technology Data Exchange (ETDEWEB)

    Bae, Sang Jin; Park, Sang Soo; Yoon, Hyun Ki; Sung, Kyu Bo; Song, Ho Young [Asan Medical Center, Ulsan Univ. College of Medicine, Seoul (Korea, Republic of); Kang, Sung Gwon [Inha Univ. College of Medicine, Inchon (Korea, Republic of)

    1999-06-01

    The purpose of this study was to evaluate the safety and the retrievability of a new covered retrievable nitinol tracheobronchial stent. Stents were knitted from 0.2mm nitinol wire, covered with polyurethane, and were 20-22mm in diameter and 2cm in length. Under fluoroscopic guidance, a stent was placed in the normal right bronchus intermedius of ten dogs. Using a retrieval hook, stent retrieval was attempted after 1 month(N=5) or 2 months(N=5). After removal, the dogs were sacrificed and their their tracheobronchial trees were examined grossly and histologically. Eleven stents were successfully placed in ten dogs. Migration and expectoration occurred in four of ten stents in nine dogs(40%). Five stents were successfully removed from six dogs(83%). Without significant difference between the two groups, mild to moderate mucosal hyperplasia was noted at the sites of stents as well as above and below them. On microscopy, three of five dogs showed pneumonia in the right middle lobes, but none of the stents was covered with epithelium. Temporary placement of a covered expandable nitinol stent in the tracheobronchial tree is feasible, but to establish its efficacy, further experimental studies are needed.

  4. [Latex covering and mechanical analysis of balloon expandable stents].

    Science.gov (United States)

    Marty, B; von Segesser, L K; Carrel, T; Turina, M

    1996-01-01

    To the moment a few stents of metallic coils or meshes are available with a sealing coverage. In the present study balloon-expandable stents have been covered with a thin layer of natural rubber latex. The physical properties of these impervious stents were compared to the conventional stents. The expansion, the loss of expansion and the deformity during and after balloon inflation have been analyzed. In the pressure zone of 4-6 bar the mechanical characteristics of the impervious stents were similar to the conventional stents. The stents were expanded at 100% related on the balloon diameter used for expansion. Additional pressure of 1 bar was necessary to expand the impervious stents. At balloon pressure below 4 bar the stents tied the balloons in the midzone. The impervious stents, expanded at 6, 8 and 10mm, underwent a loss of expansion of 10% after withdrawal of the balloons. Their configuration was barrel-shaped (4% central enlargement) due to the latex rubber, constricting the wire meshes at both ends. These preliminary results are encouraging and allow further investigations.

  5. Paclitaxel Drug-eluting Tracheal Stent Could Reduce Granulation Tissue Formation in a Canine Model

    Directory of Open Access Journals (Sweden)

    Ting Wang

    2016-01-01

    Conclusions: The paclitaxel-eluting stent could safely reduce the granulation tissue formation after stent implantation in vivo, suggesting that the paclitaxel-eluting tracheal stent might be considered for potential use in humans in the future.

  6. Tropoelastin inhibits intimal hyperplasia of mouse bioresorbable arterial vascular grafts.

    Science.gov (United States)

    Sugiura, Tadahisa; Agarwal, Riddhima; Tara, Shuhei; Yi, Tai; Lee, Yong-Ung; Breuer, Christopher K; Weiss, Anthony S; Shinoka, Toshiharu

    2017-04-01

    Neointimal hyperplasia, which results from the activation, proliferation and migration of vascular smooth muscle cells (SMCs), is a detrimental condition for vascular stents or vascular grafts that leads to stenosis. Preventing neointimal hyperplasia of vascular grafts is critically important for the success of arterial vascular grafts. We hypothesized that tropoelastin seeding onto the luminal surface of the graft would prevent neointimal hyperplasia through suppressing neointimal smooth muscle cell proliferation. In this study, we investigated the efficacy of tropoelastin seeding in preventing neointimal hyperplasia of bioresorbable arterial vascular grafts. Poly (glycolic acid) (PGA) fiber mesh coated with poly (l-lactic-co-ε-caprolactone) (PLCL) scaffolds reinforced by poly (l-lactic acid) (PLA) nano-fibers were prepared as bioresorbable arterial grafts. Tropoelastin was then seeded onto the luminal surface of the grafts. Tropoelastin significantly reduced the thickness of the intimal layer. This effect was mainly due to a substantial reduction the number of cells that stained positive for SMC (α-SMA) and PCNA in the vessel walls. Mature elastin and collagen type I and III were unchanged with tropoelastin treatment. This study demonstrates that tropoelastin seeding is beneficial in preventing SMC proliferation and neointimal hyperplasia in bioresorbable arterial vascular grafts. Small resorbable vascular grafts can block due to the over-proliferation of smooth muscle cells in neointimal hyperplasia. We show here that the proliferation of these cells is restricted in this type of graft. This is achieved with a simple dip, non-covalent coating of tropoelastin. It is in principle amendable to other grafts and is therefore an attractive process. This study is particularly significant because: (1) it shows that smooth muscle cell proliferation can be reduced while still accommodating the growth of endothelial cells, (2) small vascular grafts with an internal

  7. Plastic strains during stent deployment have a critical influence on the rate of corrosion in absorbable magnesium stents.

    Science.gov (United States)

    Galvin, Emmet; Cummins, Christy; Yoshihara, Shoichiro; Mac Donald, Bryan J; Lally, Caitríona

    2017-08-01

    Magnesium stents are a promising candidate in the emerging field of absorbable metallic stents (AMSs). In this study, the mechanical and corrosion performance of dog-bone specimens and a specific stent design of a magnesium alloy, WE43, are assessed experimentally in terms of their corrosion behaviour and mechanical integrity. It is shown that plastic strains that are induced in the struts of the stent during stent deployment have a critical influence in directing subsequent corrosion behaviour within the material. In addition, the deployment and scaffolding characteristics of the magnesium stent are elucidated and contrasted with those of a commercial stainless steel stent. The magnesium stent is found to support higher levels of cyclic strain amplitude than the stainless steel stent, even prior to degradation, and this may play a role in reducing in-stent restenosis. This study provides new insights into the experimental performance of a current AMS design and material whilst demonstrating the critical influence of plastic strain on the corrosion performance and scaffolding ability of an AMS.

  8. Author disclosure of conflict of interest in vascular surgery journals.

    Science.gov (United States)

    Forbes, Thomas L

    2011-09-01

    Advances in vascular surgery are increasingly technology-driven, and the relationships between surgeons and the medical device industry can be complex. This study reviewed conflict of interest (COI) disclosure in the vascular surgery journals regarding several selected technology-driven topics, including endovascular stent grafts (EV), carotid artery stenting (CAS), and peripheral arterial interventions (PI), to suggest further directions. Authors' COI disclosures were reviewed from all clinical papers published in 2008 and 2009 in each of six vascular surgery journals, and pertaining to three selected topics (EV, CAS, and PI). Rate of COI disclosure was evaluated as a function of journal, topic, article type (randomized trial, case series, case report, review, or meta-analysis), and authors' region of origin. Secondarily, consistency of authors' disclosure was evaluated by reviewing papers by the same author and of the same topic. Six hundred thirty-five papers were reviewed from the six journals. A COI was declared in 125 (19.7%) of these papers. This rate differed between journals (range, 3.2%-34.1%; P author writing papers describing the same general topic. COI disclosure was consistent in the majority of these instances (72.4%), but inconsistent in 32 cases (27.6%). The most common (P = .006) inconsistencies involved the same type of article in different journals (46.9%), or in the same journal (25%). Rates of disclosure of COI, and inconsistencies in disclosure in the vascular surgery literature are at least partially due to differences in journals' reporting policies, while a smaller proportion of these inconsistencies are due to individual author behavior. Journals should adopt a consistent requirement for a separate COI declaration where all relevant financial arrangements are disclosed. Copyright © 2011 Society for Vascular Surgery. Published by Mosby, Inc. All rights reserved.

  9. Biolimus-eluting biodegradable polymer-coated stent versus durable polymer-coated sirolimus-eluting stent in unselected patients receiving percutaneous coronary intervention (SORT OUT V)

    DEFF Research Database (Denmark)

    Christiansen, Evald Høj; Jensen, Lisette Okkels; Thayssen, Per

    2013-01-01

    Third-generation biodegradable polymer drug-eluting stents might reduce the risk of stent thrombosis compared with first-generation permanent polymer drug-eluting stents. We aimed to further investigate the effects of a biodegradable polymer biolimus-eluting stent compared with a durable polymer...

  10. Flow diverter effect of LVIS stent on cerebral aneurysm hemodynamics: a comparison with Enterprise stents and the Pipeline device.

    Science.gov (United States)

    Wang, Chao; Tian, Zhongbin; Liu, Jian; Jing, Linkai; Paliwal, Nikhil; Wang, Shengzhang; Zhang, Ying; Xiang, Jianping; Siddiqui, Adnan H; Meng, Hui; Yang, Xinjian

    2016-07-02

    The aim of this study was to quantify the effect of the new Low-profile Visualized Intraluminal Support (LVIS®D) device and the difference of fluid diverting effect compared with the Pipeline device and the Enterprise stent using computational fluid dynamics (CFD). In this research, we simulated three aneurysms constructed from 3D digital subtraction angiography (DSA). The Enterprise, LVIS and the Pipeline device were virtually conformed to fit into the vessel lumen and placed across the aneurysm orifice. Computational fluid dynamics analysis was performed to compare the hemodynamic differences such as WSS, Velocity and Pressure among these stents. Control referred to the unstented model, the percentage of hemodynamic changes were all compared to Control. A single LVIS stent caused more wall shear stress reduction than double Enterprise stents (39.96 vs. 30.51 %) and velocity (23.13 vs. 18.64 %). Significant reduction in wall shear stress (63.88 %) and velocity (46.05 %) was observed in the double-LVIS stents. A single Pipeline showed less reduction in WSS (51.08 %) and velocity (37.87 %) compared with double-LVIS stent. The double-Pipeline stents resulted in the most reduction in WSS (72.37 %) and velocity (54.26 %). Moreover, the pressure increased with minuscule extent after stenting, compared with the unstented model. This is the first study analyzing flow modifications associated with LVIS stents. We found that the LVIS stent has certain hemodynamic effects on cerebral aneurysms: a single LVIS stent caused more flow reductions than the double-Enterprise stent but less than a Pipeline device. Nevertheless, the double-LVIS stent resulted in a better flow diverting effect than a Pipeline device.

  11. Stent longitudinal integrity bench insights into a clinical problem.

    Science.gov (United States)

    Ormiston, John A; Webber, Bruce; Webster, Mark W I

    2011-12-01

    Standardized bench-top compression and elongation testing was undertaken to assess the longitudinal strength of contemporary stents. Insights gained may improve clinical stent choice and deployment techniques, and facilitate future stent design improvements. The hoops of coronary stents provide radial support, and connectors hold hoops together. Strut material, shape, and thickness, along with connector number and configuration, provide the balance between stent flexibility and longitudinal integrity. Longitudinal distortion manifests as length change, strut overlap, strut separation, malapposition, and luminal obstruction. These may predispose to restenosis and stent thrombosis, obstruct passage of devices, be misinterpreted as strut fracture, and require additional stenting. The force required to compress and to elongate 7 contemporary stents was measured with an Instron universal testing machine (Norwood, Massachusetts). Stents deployed in a silicone phantom damaged by a balloon or guide catheter were imaged by microcomputed tomography to understand better the appearances and effects of longitudinal distortion. Stents with 2 connectors (Boston Scientific [Natick, Massachusetts] Omega and Medtronic [Santa Rosa, California] Driver) required significantly less force to be compressed up to 5 mm and elongated by 1 mm than designs with more connectors. The 6-connector Cypher Select required significantly more force to be elongated 5 mm than other designs. Stents with 2 connectors between hoops have less longitudinal strength when exposed to compressing or elongating forces than those with more connectors. This independent, standardized study may assist stent selection in clinical situations where longitudinal integrity is important, and may aid future design improvements. Stent longitudinal strength, the resistance to shortening or elongation, appears related to the number of connectors between hoops. Using a standardized testing protocol, designs with 2 connectors

  12. Coronary stent thrombosis with vorapaxar versus placebo: results from the TRA 2° P-TIMI 50 trial.

    Science.gov (United States)

    Bonaca, Marc P; Scirica, Benjamin M; Braunwald, Eugene; Wiviott, Stephen D; O'Donoghue, Michelle L; Murphy, Sabina A; Morrow, David A

    2014-12-09

    Vorapaxar, a novel thrombin receptor antagonist, reduces cardiovascular death and recurrent thrombotic events when added to standard antiplatelet therapy in patients with stable atherosclerotic vascular disease. The goal of this study was to test the hypothesis that treatment with vorapaxar reduces the rate of coronary stent thrombosis (ST) in stable patients with a history of coronary stenting. TRA 2° P-TIMI 50 (Trial to Assess the Effects of Vorapaxar in Preventing Heart Attack and Stroke in Patients With Atherosclerosis-Thrombolysis In Myocardial Infarction 50) was a multinational, randomized, double-blind, placebo-controlled trial of vorapaxar in stable patients with prior myocardial infarction, peripheral arterial disease, or stroke. We evaluated the rates of definite ST as adjudicated by a central events committee using Academic Research Consortium (ARC) criteria. A total of 26,449 patients were randomized, with 14,042 (53%) having a history of a coronary stent implantation before randomization, and an additional 449 patients receiving a coronary stent during the trial (total 14,491). During follow-up (median 2.5 years), there were 152 definite ST events, with the majority (92%) occurring late or very late. Vorapaxar reduced ARC definite ST (1.1% vs. 1.4%, hazard ratio [HR]: 0.71, 95% confidence interval [CI]: 0.51 to 0.98; p = 0.037). The reduction was consistent, regardless of time from percutaneous coronary intervention, history of diabetes, use of drug-eluting stents, and use of dual antiplatelet therapy (DAPT) at randomization. Vorapaxar increased GUSTO moderate/severe bleeding (HR: 1.57, 95% CI: 1.26 to 1.94; p TRA 2° P-TIMI 50] [P04737]; NCT00526474). Copyright © 2014 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

  13. Optimal conjugation of catechol group onto hyaluronic acid in coronary stent substrate coating for the prevention of restenosis

    Directory of Open Access Journals (Sweden)

    Eugene Lih

    2016-12-01

    Full Text Available Although endovascular stenting has been used as an interventional therapy to treat cardio- and cerebro-vascular diseases, it is associated with recurrent vascular diseases following stent thrombosis and in-stent restenosis. In this study, a metallic stent was coated with dopamine-conjugated hyaluronic acid with different ratios of catechol group to improve hemocompatibility and re-endothelialization. Especially, we were interested in how much amount of catechol group is appropriate for the above-mentioned purposes. Therefore, a series of dopamine-conjugated hyaluronic acid conjugates with different ratios of catechol group were synthesized via a carbodiimide coupling reaction. Dopamine-conjugated hyaluronic acid conjugates were characterized with 1H-nuclear magnetic resonance and Fourier transform infrared spectroscopy, and the amount of catechol group in dopamine-conjugated hyaluronic acid was measured by ultraviolet spectrometer. Co-Cr substrates were polished and coated with various dopamine-conjugated hyaluronic acid conjugates under pH 8.5. Dopamine-conjugated hyaluronic acid amounts on the substrate were quantified by micro-bicinchoninic acid assay. Surface characteristics of dopamine-conjugated hyaluronic-acid-coated Co-Cr were evaluated by water contact angle, scanning electron microscopy, and atomic force microscopy. The hemocompatibility of the surface-modified substrates was assessed by protein adsorption and platelet adhesion tests. Adhesion and activation of platelets were confirmed with scanning electron microscopy and lactate dehydrogenase assay. Human umbilical vein endothelial cells were cultured on the substrates, and the viability, adhesion, and proliferation were investigated through cell counting kit-8 assay and fluorescent images. Obtained results demonstrated that optimal amounts of catechol group (100 µmol in the dopamine-conjugated hyaluronic acid existed in terms of various properties such as hemocompatibility and

  14. Collagen vascular disease

    Science.gov (United States)

    ... page: //medlineplus.gov/ency/article/001223.htm Collagen vascular disease To use the sharing features on this page, ... previously said to have "connective tissue" or "collagen vascular" disease. We now have names for many specific conditions ...

  15. Safety and efficacy of using the Viabahn endoprosthesis for percutaneous treatment of vascular access complications after transfemoral aortic valve implantation

    DEFF Research Database (Denmark)

    De Backer, Ole; Arnous, Samer; Sandholt, Benjamin

    2015-01-01

    Vascular access complications (VACs) remain one of the biggest challenges when performing transcatheter aortic valve implantation (TAVI). This study aimed to investigate the short- and medium-term safety and efficacy of the Viabahn endoprosthesis (Gore, Flagstaff, AZ) when used to treat TAVI......-induced vascular injury. Over a 40-month period, 354 patients underwent true percutaneous transfemoral (TF)-TAVI using a CoreValve and Prostar-XL closure system; this was our study population. A VAC leading to acute intervention occurred in 72 patients (20.3%) - of these, 18 were managed by balloon angioplasty, 48...... stenting versus patients without vascular complications. Two patients (4.5%) presented with new-onset claudication; one of them had the stent implanted covering the deep femoral artery (DFA). At medium-term follow-up (median 372 days; range 55 to 978 days) duplex ultrasound showed 100% patency...

  16. On high-cycle fatigue of 316L stents.

    Science.gov (United States)

    Barrera, Olga; Makradi, Ahmed; Abbadi, Mohammed; Azaouzi, Mohamed; Belouettar, Salim

    2014-01-01

    This paper deals with fatigue life prediction of 316L stainless steel cardiac stents. Stents are biomedical devices used to reopen narrowed vessels. Fatigue life is dominated by the cyclic loading due to the systolic and diastolic pressure and the design against premature mechanical failure is of extreme importance. Here, a life assessment approach based on the Dang Van high cycle fatigue criterion and on finite element analysis is applied to explore the fatigue reliability of 316L stents subjected to multiaxial fatigue loading. A finite element analysis of the stent vessel subjected to cyclic pressure is performed to carry out fluctuating stresses and strain at some critical elements of the stent where cracks or complete fracture may occur. The obtained results show that the loading path of the analysed stent subjected to a pulsatile load pressure is located in the safe region concerning infinite lifetime.

  17. Percutaneous antegrade ureteric stent removal using a rigid alligator forceps.

    LENUS (Irish Health Repository)

    Given, M F

    2008-12-01

    To evaluate the safety and efficacy of percutaneous antegrade ureteric stent removal using a rigid alligator forceps. Twenty patients were included in our study. Indications for ureteric stent insertion included stone disease (n = 7), malignancy (n = 8) and transplant anastomotic strictures (n = 5). Stent retrieval was carried out for proximal stent placement\\/migration in seven patients and encrustation in the remaining 13. Twenty-two stents were successfully retrieved in 20 patients. There was one technical failure (5%). There were no major complications. We had four minor complications, which included nephrostomy site pain (n = 2), periprocedural sepsis (n = 1) and a small urinoma (n = 1). All patients settled with conservative management. Percutaneous radiologically guided antegrade ureteric stent removal with an alligator forceps is safe and effective, particularly when initial surgical removal has failed.

  18. Post-biliary sphincterotomy bleeding despite covered metallic stent deployment

    Directory of Open Access Journals (Sweden)

    Gianfranco Donatelli

    2016-05-01

    Full Text Available Objectives: Several endoscopic techniques have been proposed for the management of post-sphincterotomy bleeding. Lately, self-expandable metal stents deployment has gained popularity especially as a rescue therapy when other endoscopic techniques fail. Methods-results: We report the case report of a massive post-sphincterotomy bleeding in a patient with a self-expandable metal stent in the biliary tree. Despite the presence of a correctly positioned self-expandable metal stent, a new endoscopic session was required to control the bleeding. Conclusions: Self-expandable metal stent may be useful to manage post-endoscopic sphincterotomy bleeding. However, up to now there is no specifically designed self-expandable metal stent for such complication. Large new designed self-expandable metal stent may be a useful tool for biliary endoscopist.

  19. Stone Formation and Fragmentation in Forgotten Ureteral Double J Stent

    Directory of Open Access Journals (Sweden)

    Okan Bas

    2014-02-01

    Full Text Available Aim: Nowadays, ureteral stents play an essential role in various endourological and open surgical procedures and common procedures performed in daily urological practice. However, stents can cause significant complications such as migration, infection, fragmentation, stone formation and encrustation, especially when forgotten for a long period. Objectives: We present our experience in endoscopic management of forgotten ureteral stents with a brief review of current literature. Case presentation: A total of 2 patients with forgotten ureteral stents were treated with endourological approaches in our department. Indwelling durations were 18 months and 36 months. After treatment both patients were stone and stent free. Conclusion: An endourological approach is effective for stent and stone removal after a single anesthesia session with minimal morbidity and short hospital stay. However, therapeutic strategy is also determined by the technology available. The best treatment would be the prevention of this complication by providing detailed patient education.

  20. Reação histopatológica da parede da aorta abdominal ao stent não recoberto Histopathological reaction of the abdominal aorta wall to non-covered stents

    Directory of Open Access Journals (Sweden)

    Rubio Bombonato

    2006-06-01

    Full Text Available OBJETIVO: Avaliar a reação histopatológica da parede aorta abdominal, em suínos, no nível das artérias renais, na presença de stent metálico não recoberto. MÉTODO: Foi estudada histopatologicamente a aorta abdominal de 10 suínos, com peso médio de 86,6 quilos e idade média de 6 meses, submetidos a implante de stent metálico posicionado na aorta, no nível das artérias renais, após 100 dias do implante. Os stents foram liberados por auto-expansão com laparotomia. Os cortes histológicos foram realizados nos seguintes locais: 1 transição entre a aorta normal e aorta contendo stent; 2 aorta contendo o stent; 3 porção contendo os óstios das artérias renais, 4 linfonodos periaórticos e, 5 parênquima renal. As lâminas foram coradas pela técnica da hematoxilina e eosina. RESULTADOS: Os achados macroscópicos revelaram: linfonodomegalia periaórtica; espessamento da parede aórtica; artérias lombares e renais pérvias; estrutura anatômica renal normal. Análises microscópicas, próximas aos stents, evidenciaram espessamento da parede vascular, secundário à fibrose intimal e camada média comprometida com fibrose intersticial. Medidas micrométricas da parede aórtica com o stent, comparada à aorta sem o stent, apresentaram aumento da espessura da parede (75,9% por hiperplasia da camada íntima secundária à proliferação de fibroblastos; depósitos de colágeno com infiltrado inflamatório e granulomas do tipo corpo estranho. CONCLUSÃO: O stent de aço inoxidável descoberto, implantado na aorta de suínos, produziu importante reação inflamatória, com fibrose nas camadas média e íntima, evidenciada pelas análises histopatológicas e a sua presença não comprometeu o estado pérvio da aorta e dos ramos lombares e renais.OBJECTIVE: To evaluate the histopathological reaction of the abdominal aorta wall in pigs' renal arteries to the presence of non-covered stainless steel stents. METHODS: The abdominal aorta of

  1. Is endovascular treatment with multilayer flow modulator stent insertion a safe alternative to open surgery for high-risk patients with thoracoabdominal aortic aneurysm?

    OpenAIRE

    Pinto, Carolline; Garas, George; Harling, Leanne; Darzi, Ara; Casula, Roberto; Athanasiou, Thanos

    2017-01-01

    A best evidence topic in cardiothoracic and vascular surgery was written according to a structured protocol. The question addressed was whether endovascular treatment with multilayer flow modulator stents (MFMS) can be considered a safe alternative to open surgery for high-risk patients with thoracoabdominal aortic aneurysm (TAAA). Altogether 27 papers were identified using the reported search, of which 11 represented the best evidence to answer the clinical question. The authors, journal, da...

  2. Computer modeling for the prediction of thoracic aortic stent graft collapse.

    Science.gov (United States)

    Pasta, Salvatore; Cho, Jae-Sung; Dur, Onur; Pekkan, Kerem; Vorp, David A

    2013-05-01

    TASG wall, a load that would portend TASG collapse. Patient-specific computational modeling may allow for identification of patients with high risk of TASG collapse and guide preventive intervention. A potentially devastating complication that may occur after endovascular repair of traumatic thoracicaortic injuries is stent graft collapse. Although usually asymptomatic, stent graft collapse may be accompanied by adverse hemodynamic consequences. Numerous anatomic and device-related factors contribute to the development of collapse, but predictive factors have not yet been clearly defined. In the present study, we assessed the relevant hemodynamics and solid mechanics underlying stent graft collapse using a computational fluid-structure interaction framework of stent graft malapposition. Our findings suggest that both increased stent graft angle and extension into the aortic arch lead to a markedly increased transmural pressure across the stent graft wall, portending collapse. Patient-specific computational modeling may allow for identification of patients at high risk for collapse and aid in planning for an additional, prophylactic intervention to avert its occurrence. Copyright © 2013 Society for Vascular Surgery. Published by Mosby, Inc. All rights reserved.

  3. Safety and efficacy of everolimus-eluting stents for bare-metal 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); Torguson, Rebecca; 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)

    2015-04-15

    Objective: The aim of this study was to compare the safety and efficacy of the everolimus-eluting stents (EES) with the paclitaxel-eluting stent (PES) and sirolimus-eluting stent (SES) for the treatment of bare-metal in-stent restenosis. Background: The optimal treatment for bare-metal in-stent restenosis remains controversial. Methods: The study cohort comprised 322 consecutive patients (543 lesions) who presented with bare-metal in-stent restenosis to our institution and underwent coronary artery stent implantation with EES (114 patients; 181 lesions), PES (65 patients; 116 lesions) and SES (143 patients; 246 lesions). 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 events (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 except for age and chronic kidney disease. The 1-year analyzed clinical parameters were similar in the three groups: death (EES = 3.5%, PES = 4.6%, SES = 4.2%; p = 0.94), MI (EES = 3.5%, PES = 6.3%, SES = 2.1%; p = 0.31), TLR (EES = 9.8%, PES = 9.5%, SES = 5.7%; p = 0.42), TVR (EES = 14.3%, PES = 11.1%, SES = 11.3%; p = 0.74), definite ST (EES = 0.9%, PES = 3.1%, SES = 3.5%; p = 0.38) and MACE (EES = 14.0%, PES = 15.4%, SES = 10.5%; p = 0.54). Male gender (hazard ratio = 0.47; 95% confidence interval = 0.25–0.88) and number of treated lesions (hazard ratio = 1.47; 95% confidence interval = 1.06–2.05) were found to be independent predictors of MACE. Conclusion: The results of the present study indicate that EES may provide similar safety and efficacy as first generation DES for the treatment of patients presenting with bare-metal in-stent restenosis.

  4. LG tools for asymmetric wargaming

    Science.gov (United States)

    Stilman, Boris; Yakhnis, Alex; Yakhnis, Vladimir

    2002-07-01

    Asymmetric operations represent conflict where one of the sides would apply military power to influence the political and civil environment, to facilitate diplomacy, and to interrupt specified illegal activities. This is a special type of conflict where the participants do not initiate full-scale war. Instead, the sides may be engaged in a limited open conflict or one or several sides may covertly engage another side using unconventional or less conventional methods of engagement. They may include peace operations, combating terrorism, counterdrug operations, arms control, support of insurgencies or counterinsurgencies, show of force. An asymmetric conflict can be represented as several concurrent interlinked games of various kinds: military, transportation, economic, political, etc. Thus, various actions of peace violators, terrorists, drug traffickers, etc., can be expressed via moves in different interlinked games. LG tools allow us to fully capture the specificity of asymmetric conflicts employing the major LG concept of hypergame. Hypergame allows modeling concurrent interlinked processes taking place in geographically remote locations at different levels of resolution and time scale. For example, it allows us to model an antiterrorist operation taking place simultaneously in a number of countries around the globe and involving wide range of entities from individuals to combat units to governments. Additionally, LG allows us to model all sides of the conflict at their level of sophistication. Intelligent stakeholders are represented by means of LG generated intelligent strategies. TO generate those strategies, in addition to its own mathematical intelligence, the LG algorithm may incorporate the intelligence of the top-level experts in the respective problem domains. LG models the individual differences between intelligent stakeholders. The LG tools make it possible to incorporate most of the known traits of a stakeholder, i.e., real personalities involved in

  5. Fourth update on CT angiography of coronary stents: in vitro evaluation of 24 novel stent types.

    Science.gov (United States)

    Hickethier, Tilman; Wenning, Justus; Doerner, Jonas; Maintz, David; Michels, Guido; Bunck, Alexander C

    2017-01-01

    Background Non-invasive evaluation of coronary stent patency by coronary computed tomography angiography (cCTA) remains challenging. Multiple studies showed that CT technology but also individual stent design strongly influence the assessability of coronary stents by cCTA. Purpose To expand the available data on cCTA characteristics of coronary stents by 24 novel types to help interpreting examinations of patients after stent placement and selecting which stents are suitable for assessment by cCTA. Material and Methods Twenty-four novel coronary stents (17 cobalt-chromium, six stainless-steel, one platinum-chromium) were examined in a coronary phantom. Standard cCTA parameters with stent-specific algorithms were used. Image quality was quantified for each stent using established parameters (in-stent attenuation alteration and visible lumen diameter). Results Most stents (n = 14) showed lumen visibilities of 45-55%. No severe restriction of lumen visibility (>60%) was found. The majority of stents (n = 13) caused only small intraluminal attenuation deviations and no severe alterations (>20%) were found. When grouped by manufacturing material, no significant differences were found between cobalt-chromium and stainless-steel with identical mean visible diameters (1.52 ± 0.17 mm vs. 1.52 ± 0.13 mm) and comparable attenuation alterations (35.04 ± 16.56 HU vs. 21.25 ± 14.60 HU). The only platinum-chromium stent showed a smaller visible diameter (1.23 mm) and higher attenuation alteration (41.70 HU), but was also deemed to be assessable by cCTA. Conclusion All 24 novel evaluated stents are eligible for non-invasive evaluation by cCTA without significant differences between cobalt-chromium and stainless-steel stents. This updated catalogue of CT appearances of current coronary stents may serve as reference when taking care of patients with stents in need of coronary imaging.

  6. The nature and pattern of coronary stent recalls.

    Science.gov (United States)

    Kumar, Sanjay; Innasimuthu, Antony L; Marmur, Jonathan D

    2014-09-01

    Each year, over 1 million percutaneous coronary interventions (PCIs) are performed in the United States. Coronary stents have been shown to reduce restenosis or abrupt vessel closure and therefore have improved the success of PCI. Rarely, manufacturers recall stents due to unanticipated problems. We sought to study the extent and pattern of stent recall. To determine the number and rate of stent recall and safety alerts, to identify trends in the rates, and to identify the nature of stent recalls. The Food and Drug Administration (FDA; http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfRES/res.cfm) and Healthcare Recall Management websites (RASMAS; https://alerts.rasmas.noblis.org/rasmas/c/selectViewAlertList.do) were searched. The search terms for recall were, "coronary stent" or "stent." Dates were searched between November 2002 and June 2013. There were 17 coronary stent recalls involving almost 500,000 units; 12 recalls (71%) were before 2006 and 5 recalls (29%) were after. Thirteen recalls (76%) consisted of class II recalls (moderate hazard); the remaining 4 were equally split between class I (severe hazard) and class III (mild hazard; 12% each). The common reasons for recall were concerns with sterility (29%) followed by wrong labeling/packaging (23%) and impaired delivery of stent (18%). In terms of units involved with recalls, 98% (472,189/481,131) were related to wrong labeling/ packaging or misbranding, while 0.1% (542/481,131) were related to potential for broken struts or crack in inflation port hub or sterility. However, approximately 2% of units were related to the potentially lethal problem of impaired balloon inflation. Recalls involved multiple manufacturers with various stent types. The overall incidence of coronary stent recall is low and has declined over the years. The majority of stent recalls are of moderate hazard. However, due to the possibility of serious injury, clinicians should be aware of recalls.

  7. Pseudoaneurisme på arteria carotis interna behandlet med stent

    DEFF Research Database (Denmark)

    Benian, Cemil; Wagner, Aase; Cortsen, Marie

    2013-01-01

    Extracranial internal carotid artery aneurysms (EACIAs) are rare. Untreated they have a high stroke rate. Traditionally the treatment has been surgery or endovascular intervention with coils. Both are associated with relatively high complication rates. Another treatment option is endovascular...... intervention with covered stent, which provides one-step closure of the aneurysm. As in the case story it can be complicated with in-stent occlusion. Therefore we recommend balloon occlusion test before treatment of EACIAs with covered stent....

  8. Role of biomaterials in prevention of in-stent restenosis.

    Science.gov (United States)

    Laçin, Nelisa T; Utkan, Guldem G

    2014-07-01

    Coronary balloon angioplasty and coronary stenting are the procedures used in healing coronary artery disease. However, injury of arteries during angioplasty and stenting causes cell stimulations in tissue. Cell movement and thrombosis lead to re-narrowing of widened vessel called restenosis. Several new types of carriers and technology have been developed to suppress and/or prevent restenosis. Authors review the polymeric materials featured in drug/gene carrier systems, nanovehicles, and stent coating materials against restenosis. © 2013 Wiley Periodicals, Inc.

  9. Loan sales under asymmetric information

    OpenAIRE

    Vargas Martínez, Mónica

    2010-01-01

    Loans are illiquid assets that can be sold in a secondary market even that buyers have no certainty about their quality. I study a model in which a lender has access to new investment opportunities when all her assets are illiquid. To raise funds, the lender may either borrow using her assets as collateral, or she can sell them in a secondary market. Given asymmetric information about assets quality, the lender cannot recover the total value of her assets. There is then a role for the governm...

  10. Caracterización de la restenosis de stents coronarios convencionales y liberadores de medicamentos en pacientes incluidos en el registro DRug Eluting STent (DREST Characterization of conventional coronary stents restenosis and drug eluting stents in patients included in the Drug Eluting Stent Registry (DREST

    Directory of Open Access Journals (Sweden)

    Jorge A Arroyave C

    2012-06-01

    Full Text Available Introducción y objetivos: los stents convencionales presentan tasas de restenosis intrastent entre 10% y 60%, mientras los stents liberadores de fármacos alcanzan el 10%. Para Latinoamérica, no hay reportes de restenosis intrastent en comparación con los stents convencionales y los stents liberadores de fármacos. En este estudio se describen aspectos asociados a este evento en pacientes atendidos en un centro de alta complejidad en Colombia. Métodos: análisis retrospectivo de pacientes con restenosis intrastent incluidos en el registro DRug ELuting STent (DREST entre los años 1994 y 2011, en el que se compararon características basales, datos técnicos y supervivencia de los pacientes con stent convencional y stent liberador de fármacos. Resultados: se evidenció restenosis intrastent en 269 con stent convencional (11,5% y en 65 con stent liberador de fármacos (12,2%, sin diferencias significativas al comparar por género (p=0,983 o edad (p=0,55. La dislipidemia fue el factor de riesgo más significativo asociado a la restenosis intrastent de los stents liberadores de fármacos (pIntroduction and Objectives: Bare metal stents have stent restenosis rates between 10% and 60%, while drug-eluting stents reach 10%. In Latin America, there are no reports of stent restenosis between bare-metal stents and drug eluting stents. This study describes aspects associated with this event in patients treated at a center of high complexity in Colombia. Methods: Retrospective analysis of patients with stent restenosis included in the Drug Eluting Stent Registry (DREST between 1994 and 2011, which compared baseline characteristics, technical data and survival of patients with bare metal stents and drug eluting stents. Results: We found stent restenosis with bare metal stents in 269 patients (11.5% and in 65 with drug-eluting stent (12.2% without significant differences between gender (p = 0.983 or age (p = 0 , 55. Dyslipidemia was the most significant

  11. A novel antithrombotic coronary stent: lysine-poly(HEMA)-modified cobalt-chromium stent with fibrinolytic activity.

    Science.gov (United States)

    Wang, Shasha; Li, Dan; Chen, Hong; Wu, Zhaoqiang; Xu, Yajun; Brash, John L

    2013-01-01

    Prevention of coagulation appears not to be possible when a foreign surface is in contact with blood; the alternative concept of a clot lysing surface has therefore been suggested. In this work, a mimic of the fibrinolytic system was constructed on L605 cobalt-chromium coronary stents. Lysine which, immobilized on a surface, has been shown previously to adsorb plasminogen in contact with blood was attached to the stent using poly(2-hydroxyethyl methacrylate) (poly(HEMA)) as a spacer. The lysine-poly(HEMA) modified stent was shown to have low nonspecific protein adsorption and to bind plasminogen in high quantity from plasma. Following exposure to plasma and treatment with tissue plasminogen activator, the lysine-modified stents showed clot-lysing properties in vitro while the unmodified L605 stents did not. It was shown that the modified stents retained their clot lysing properties after 24 h exposure to plasma.

  12. Ex vivo blood vessel bioreactor for analysis of the biodegradation of magnesium stent models with and without vessel wall integration.

    Science.gov (United States)

    Wang, Juan; Liu, Lumei; Wu, Yifan; Maitz, Manfred F; Wang, Zhihong; Koo, Youngmi; Zhao, Ansha; Sankar, Jagannathan; Kong, Deling; Huang, Nan; Yun, Yeoheung

    2017-03-01

    Current in vitro models fail in predicting the degradation rate and mode of magnesium (Mg) stents in vivo. To overcome this, the microenvironment of the stent is simulated here in an ex vivo bioreactor with porcine aorta and circulating medium, and compared with standard static in vitro immersion and with in vivo rat aorta models. In ex vivo and in vivo conditions, pure Mg wires were exposed to the aortic lumen and inserted into the aortic wall to mimic early- and long-term implantation, respectively. Results showed that: 1) Degradation rates of Mg were similar for all the fluid diffusion conditions (in vitro static, aortic wall ex vivo and in vivo); however, Mg degradation under flow condition (i.e. in the lumen) in vivo was slower than ex vivo; 2) The corrosion mode in the samples can be mainly described as localized (in vitro), mixed localized and uniform (ex vivo), and uniform (in vivo); 3) Abundant degradation products (MgO/Mg(OH)2 and Ca/P) with gas bubbles accumulated around the localized degradation regions ex vivo, but a uniform and thin degradation product layer was found in vivo. It is concluded that the ex vivo vascular bioreactor provides an improved test setting for magnesium degradation between static immersion and animal experiments and highlights its promising role in bridging degradation behavior and biological response for vascular stent research. Magnesium and its alloys are candidates for a new generation of biodegradable stent materials. However, the in vitro degradation of magnesium stents does not match the clinical degradation rates, corrupting the validity of conventional degradation tests. Here we report an ex vivo vascular bioreactor, which allows simulation of the microenvironment with and without blood vessel integration to study the biodegradation of magnesium implants in comparison with standard in vitro test conditions and with in vivo implantations. The bioreactor did simulate the corrosion of an intramural implant very well, but

  13. Comparison of Recanalization and In-stent Stenosis between LVIS stent and Enterprise stent-assisted coiling for 254 intracranial aneurysms.

    Science.gov (United States)

    Feng, Xin; Qian, Zenghui; Liu, Peng; Zhang, Baorui; Wang, Luyao; Guo, Erkang; Wen, Xiaolong; Xu, Wenjuan; Jiang, Chuhan; Wu, Zhongxue; Li, Youxiang; Liu, Aihua

    2017-09-25

    We compared the rates of recanalization and in-stent stenosis between the Enterprise and Low-profile Visualized Intraluminal Support(LVIS) stent deployments for intracranial aneurysms(IAs), and the factors associated therein. In total, 142 patients with 161 IAs were treated by LVIS stent-assisted coiling and 111 patients with 142 IAs were treated by Enterprise stent-assisted coiling, respectively, from June 2014 to July 2016 at our institute. Procedure-related complications, angiographic follow-up results, and clinical outcomes were statistically analyzed. The rates of initially complete and near-complete occlusion of the IAs immediately after the procedure between the LVIS and Enterprise groups were similar(94.3% vs 89.9%, P=0.275). Follow-up data identified that the complete and near-complete occlusion rates and recanalization rates were similar for the two groups(96.6% vs 92.1%, P =0.330; 8.0%vs 13.5%; P=0.245). On logistic regression analysis,a higher size ratio(SR) was significantly associated with the recanalization of aneurysms in the Enterprise group,but not in the LVIS group. The rate of moderate and severe in-stent stenosis was lower in the LVIS group (10.2%) than in the Enterprise group (16.8%), with no statistically significant difference (P=0.198). Our study demonstrated acceptable rates of complete and near-complete occlusion with both LVIS and Enterprise stents. LVIS stents may achieve lower rate of recanalization and in-stent stenosis than Enterprise, although this difference was not significant. Higher SR (≥2) was a significant predictor of recanalization in IAs treated with Enterprise stents, but not those treated with LVIS stents. Copyright © 2017. Published by Elsevier Inc.

  14. Percutaneous nephrostomy and antegrade ureteral stenting: technique - indications - complications

    Energy Technology Data Exchange (ETDEWEB)

    Hausegger, Klaus A. [Klagenfurt General Hospital, Department of Radiology, Klagenfurt (Austria); Portugaller, Horst R. [University Hospital of Graz, Department of Radiology, Graz (Austria)

    2006-09-15

    In this review the technique, indication for and complications of percutaneous nephrostomy (PCN) and antegrade ureter stent insertion are described. In the majority of the cases PCN is performed to relieve urinary obstruction, which can be of benign or malignant nature. Another indication for PCN is for treatment of urinary fistulas. PCN can be performed under ultrasound and/or fluoroscopic guidance, with a success rate of more than 90%. The complication rate is approximately 10% for major and minor complications together and 4-5% for major complications only. Percutaneous antegrade double-J stent insertion usually is performed if retrograde ureter stenting has not been successful. However, especially in malignant obstructions, the success rate for antegrade stenting is higher than for retrograde transvesical double-J stent insertion. In the case of severe infection and bleeding after PCN JJ-stent insertion may be contraindicated so long as there is no sufficient concomitant drainage via a PCN. Lower urinary tract dysfunction should be excluded before stent placement. The complication rate is 2-4%. Consequent stent surveillance with regular stent exchange is mandatory. (orig.)

  15. Protein losing enteropathy secondary to a pulmonary artery stent

    Directory of Open Access Journals (Sweden)

    Narayanswami Sreeram

    2012-01-01

    Full Text Available A 2-year-old patient with hypoplastic left heart syndrome presented 6 months following Fontan completion with protein-losing enteropathy (PLE. He had undergone stent implantation in the left pulmonary artery after the Norwood procedure, followed by redilation of the stent prior to Fontan completion. Combined bronchoscopic and catheterization studies during spontaneous breathing confirmed left bronchial stenosis behind the stent, and diastolic systemic ventricular pressure during expiration of 25 mm Hg. We postulate that the stent acts as a valve, against which the patient generates high expiratory pressures, which are reflected in the ventricular diastolic pressure. This may be the cause of PLE.

  16. [Finite Element Analysis of Intravascular Stent Based on ANSYS Software].

    Science.gov (United States)

    Shi, Gengqiang; Song, Xiaobing

    2015-10-01

    This paper adopted UG8.0 to bulid the stent and blood vessel models. The models were then imported into the finite element analysis software ANSYS. The simulation results of ANSYS software showed that after endothelial stent implantation, the velocity of the blood was slow and the fluctuation of velocity was small, which meant the flow was relatively stable. When blood flowed through the endothelial stent, the pressure gradually became smaller, and the range of the pressure was not wide. The endothelial shear stress basically unchanged. In general, it can be concluded that the endothelial stents have little impact on the flow of blood and can fully realize its function.

  17. Systematic review: Temporary stent placement for benign ruptures or anastomotic leaks with special emphasis on stent type

    OpenAIRE

    2011-01-01

    Abstract Background: Placement of self-expanding metal stents (SEMS) or plastic stents (SEPS) has emerged as a minimally invasive treatment option for benign esophageal ruptures and leaks; however, it is not clear which stent type should be preferred. Aim & Methods: A pooled analysis was performed after searching PubMed and EMBASE databases for studies regarding placement of fully covered and partially covered SEMS (FSEMS and PSEMS) and SEPS for this indication. Data were pool...

  18. Next-generation drug-eluting stents in coronary artery disease: focus on everolimus-eluting stent (Xience V®

    Directory of Open Access Journals (Sweden)

    Imad Sheiban

    2008-02-01

    Full Text Available Imad Sheiban1, Gianluca Villata1, Mario Bollati1, Dario Sillano1, Marzia Lotrionte2, Giuseppe Biondi-Zoccai11Interventional Cardiology, Division of Cardiology, University of Turin, Turin, Italy; 2Institute of Cardiology, Catholic University, Rome, ItalyAbstract: Percutaneous coronary revascularization has been a mainstay in the management of coronary artery disease since its introduction in the late 1970s. Bare-metal stents and, more recently, first-generation drug-eluting stents (DES, such as sirolimus-eluting (Cypher® and paclitaxel-eluting stents (Taxus®, have further improved results of percutaneous coronary intervention (PCI by improving early results and reducing the risk of restenosis. There is currently debate on the safety of these first-generation DES, given the potential for late stent thrombosis, especially after discontinuation of dual antiplatelet therapy. There are well known caveats on the performance of their respective metallic stent platforms, delivery, and dilation systems, and polymer coatings. Second-generation DES, such as zotarolimus-eluting (Endeavor® and everolimus-eluting stents (Xience V®, have recently become available in the USA and/or Europe. The Xience V stent holds the promise of superior anti-restenotic efficacy as well as long-term safety. In addition, this stent is based on the Multi-link platform and delivery system. Recently available data already suggest the superiority of the Xience V stent in comparison to the Taxus stent in terms of prevention of restenosis, without significant untoward events. Nonetheless, the number of patients studied and the follow-up duration are still too limited to enable definitive conclusions. Only indirect meta-analyses can be used to date to compare the Xience V with the Cypher. This systematic review tries to provide a concise and critical appraisal of the data in support of the Xience V everolimus-eluting stent.Keywords: coronary artery disease, everolimus, percutaneous

  19. Design Optimisation of Coronary Artery Stent Systems.

    Science.gov (United States)

    Bressloff, Neil W; Ragkousis, Giorgos; Curzen, Nick

    2016-02-01

    In recent years, advances in computing power and computational methods have made it possible to perform detailed simulations of the coronary artery stenting procedure and of related virtual tests of performance (including fatigue resistance, corrosion and haemodynamic disturbance). Simultaneously, there has been a growth in systematic computational optimisation studies, largely exploiting the suitability of surrogate modelling methods to time-consuming simulations. To date, systematic optimisation has focussed on stent shape optimisation and has re-affirmed the complexity of the multi-disciplinary, multi-objective problem at hand. Also, surrogate modelling has predominantly involved the method of Kriging. Interestingly, though, optimisation tools, particularly those associated with Kriging, haven't been used as efficiently as they could have been. This has especially been the case with the way that Kriging predictor functions have been updated during the search for optimal designs. Nonetheless, the potential for future, carefully posed, optimisation strategies has been suitably demonstrated, as described in this review.

  20. Asymmetric liberations in exterior resonances

    Science.gov (United States)

    Beauge, C.

    1994-10-01

    The purpose of this paper is to present a general analysis of the planar circular restricted problem of three bodies in the case of exterior mean-motion resonances. Particularly, our aim is to map the phase space of various commensurabilities and determine the singular solutions of the averaged system, comparing them to the well-known case of interior resonances. In some commensurabilities (e.g. 1/2, 1/3) we show the existence of asymmetric librations; that is, librations in which the stationary value of the critical angle theta = (p+q) lambda1-p lambda-q pi is not equal to either zero or pi. The origin, stability and morphogenesis of these solutions are discussed and compared to symmetric librations. However, in some other resonances (e.g. 2/3, 3/4), these fixed points of the mean system seem to be absent. Librations in such cases are restricted to theta = O mod(pi). Asymmetric singular solutions of the plane circular problem are unknown in the case of interior resonances and cannot be reproduced by the reduced Andoyer Hamiltonian known as the Second Fundamental Model for Resonance. However, we show that the extended version of this Hamiltonian function, in which harmonics up to order two are considered, can reproduce fairly well the principal topological characteristics of the phase space and thereby constitutes a simple and useful analytical approximation for these resonances.

  1. Asymmetric Laguerre-Gaussian beams

    Science.gov (United States)

    Kovalev, A. A.; Kotlyar, V. V.; Porfirev, A. P.

    2016-06-01

    We introduce a family of asymmetric Laguerre-Gaussian (aLG) laser beams. The beams have been derived via a complex-valued shift of conventional LG beams in the Cartesian plane. While propagating in a uniform medium, the first bright ring of the aLG beam becomes less asymmetric and the energy is redistributed toward peripheral diffraction rings. The projection of the orbital angular momentum (OAM) onto the optical axis is calculated. The OAM is shown to grow quadratically with increasing asymmetry parameter of the aLG beam, which equals the ratio of the shift to the waist radius. Conditions for the OAM becoming equal to the topological charge have been derived. For aLG beams with zero radial index, we have deduced an expression to define the intensity maximum coordinates and shown the crescent-shaped intensity pattern to rotate during propagation. Results of the experimental generation and rotation of aLG beams agree well with theoretical predictions.

  2. Thin lenses of asymmetric power

    Directory of Open Access Journals (Sweden)

    W. F. Harris

    2009-12-01

    Full Text Available It is generally supposed that thin systems, including refracting surfaces and thin lenses, have powers that are necessarily symmetric.  In other words they have powers which can be represented assymmetric dioptric power matrices and in the familar spherocylindrical form used in optometry and ophthalmology.  This paper shows that this is not correct and that it is indeed possible for a thin system to have a power that is not symmetric and which cannot be expressed in spherocylindrical form.  Thin systems of asymmetric power are illustratedby means of a thin lens that is modelled with small prisms and is chosen to have a dioptric power ma-trix that is antisymmetric.  Similar models can be devised for a thin system whose dioptric power matrix is any  2 2 ×  matrix.  Thus any power, symmetric, asymmetric or antisymmetric, is possible for a thin system.  In this sense our understanding of the power of thin systems is now complete.

  3. Endovascular treatment of peripheral arterial injury with covered stents: an experimental study in pigs

    Directory of Open Access Journals (Sweden)

    Sergio Belczak

    2011-01-01

    Full Text Available OBJECTIVE: To evaluate the feasibility of using endovascular repair to treat penetrating arterial injuries with covered stents. Feasibility was examined according to the circumferential extent of the injury. INTRODUCTION: Surgical trauma often increases the risk of major morbidity and mortality associated with vascular injury, and endovascular repair has many advantages in such situations. METHODS: Twenty white male domestic pigs weighing 28-38 kg with controlled vascular injuries were divided into four equal groups according to the circumferential extent of their vascular lesion (i.e., no lesion, lesion 50%, and complete lesion. The left common carotid artery was dissected with proximal and distal control, and this procedure was followed by controlled sectioning of the arterial wall. Local manual compression was applied for 10 min and was followed by endovascular repair with the placement of a 5x50 mm VIABHAN TM covered stent using the femoral approach. We also monitored additional variables, such as the duration of the procedures (the mean was 56.3 ± 19.1 min, ultrasound parameters (e.g., maximum arterial diameter, peak systolic and diastolic velocity, and resistance index, arteriography findings, and fluctuations in vital signs (e.g., cardiac output, arterial pressure, and central venous pressure. RESULTS: The experimental procedure was found to be feasible and reproducible. Repairs were successful in all animals in the control (no lesion and 50% group and in one pig in the complete lesion group. DISCUSSION: The endovascular repair of an arterial injury is possible, but success depends on the circumferential extent of the arterial lesion. The present experimental model, which involved endovascular techniques, highlighted important factors that must be considered in future studies involving similar animals and materials.

  4. Retrograde open mesenteric stenting for acute mesenteric ischemia.

    Science.gov (United States)

    Blauw, Juliette T M; Meerwaldt, Robert; Brusse-Keizer, Marjolein; Kolkman, Jeroen J; Gerrits, Dick; Geelkerken, Robert H

    2014-09-01

    Acute mesenteric ischemia (AMI) encompasses the sequels of end-stage untreated chronic mesenteric ischemia and acute mesenteric artery thrombosis. Percutaneous mesenteric artery stenting (PMAS) is the preferred treatment of patients with AMI but is not always feasible. Retrograde open mesenteric stenting (ROMS) is a hybrid technique that combines the advantages of open surgical and endovascular approaches. The literature on the results of this new technique is scarce. The aim of this study was to evaluate the results of ROMS in a consecutive series of patients with AMI. All patients with emergent mesenteric revascularization for AMI between January 2007 and September 2011 were entered in our prospective registry. Technical success, mortality, patency, clinical success, and complication rate at 30 days and 6 and 12 months were assessed. Sixty-eight patients presented with AMI and 54 underwent PMAS, of which four were unsuccessful and followed by ROMS. Eleven patients were directly treated with ROMS, making a total of 15 patients (10 women and five men; median age, 66 years [interquartile range, 54-73 years]). In all patients, only the superior mesenteric artery was revascularized. In nine of the 15 patients, all three mesenteric arteries were severely stenotic or occluded. Technical success was achieved in 14 patients. At ROMS in two patients, the small bowel was severely ischemic. One of these patients needed a partial bowel resection because of irreversible transmural ischemia. At 30 days, the mortality rate was 20% and the primary patency was 92%. Ten patients underwent unplanned relaparotomy, of whom one needed resection of a large part of the small bowel. At 12 months, the mortality rate was still 20%. The primary patency was 83%. Primary assisted patency was 91%, and secondary patency was 100%. Clinical success at 30 days, 6 months, and 12 months, respectively, was 73%, 67%, and 67%. AMI is still a devastating event. If PMAS is not feasible, ROMS is a reliable

  5. Reperfusion hemorrhage following superior mesenteric artery stenting.

    LENUS (Irish Health Repository)

    Moore, Michael

    2012-02-03

    Percutaneous transluminal angioplasty and stent placement is now an established treatment option for chronic mesenteric ischemia and is associated with low mortality and morbidity rates. We present a case of reperfusion hemorrhage complicating endovascular repair of superior mesenteric artery stenosis. Although a recognized complication following repair of carotid stenosis, hemorrhage has not previously been reported following mesenteric endovascular reperfusion. We describe both spontaneous cessation of bleeding and treatment with coil embolization.

  6. The mechanism by which an asymmetric distribution of plant growth hormone is attained

    Science.gov (United States)

    Bandurski, Robert S.; Schulze, Aga; Jensen, Philip; Desrosiers, Mark; Epel, Bernard; Kowalczyk, Stanley

    Zea mays (sweet corn) seedlings attain an asymmetric distribution of the growth hormone indole-3-acetic acid (IAA) within 3 minutes following a gravity stimulus. Both free and esterified IAA (that is total IAA) accumulate to a greater extent in the lower half of the mesocotyl cortex of a horizontally placed seedling than in the upper half. Thus, changes in the ratio of free IAA to ester IAA cannot account for the asymmetric distribution. Our studies demonstrate there is no de novo synthesis of IAA in young seedlings. We conclude that asymmetric IAA distribution is attained by a gravity-induced, potential-regulated gating of the movement of IAA from kernel to shoot and from stele to cortex. As a working theory, which we call the Potential Gating Theory, we propose that perturbation of the plant's bioelectric field, induced by gravity, causes opening and closing of transport channels in the plasmodesmata connecting the vascular stele to the surrounding cortical tissues. This results in asymmetric growth hormone distribution which results in the asymmetric growth characteristic of the gravitropic response.

  7. Development and evaluation of a centralised computerised registry for ureteric stents: completing the audit cycle.

    Science.gov (United States)

    Davis, N F; Murray, G; O'Connor, T; Browne, C; MacCraith, E; Galvin, D; Mulvin, D; Quinlan, D; Lennon, G

    2017-11-01

    A forgotten ureteric stent may result in severe renal impairment leading to nephrectomy. To compare the effectiveness of a centralised computerised registry for monitoring ureteric stent activity with a previously established theatre stent logbook system. This prospective audit was performed in two 9-monthly intervals. During the first interval, insertion/removal of a ureteric stent was documented in a specific theatre stent logbook. In the second interval, an electronic centralised computerised registry was developed to document insertion/removal of a ureteric stent onto an accessible hospital server. A computerised traffic-light system was also developed to identify patients with an indwelling stent for >3 months. The primary outcome variable was the number of prolonged indwelling ureteric stents in both groups. During the first time interval, 188 ureteric stents were inserted and 182 (96%) were removed or changed. Six (4%) patients underwent insertion of a ureteric stent for a prolonged period of time (>6 months). This subgroup required complex endourological intervention for stent removal due to encrustation. During the second time interval, 157 ureteric stents were inserted and all patients had their stent removed or changed within 6 months. No patients in this group were lost to follow-up. This study demonstrates that a centralised computerised ureteric stent registry is superior to a conventional logbook for monitoring ureteric stent activity. We propose the introduction a centralised nationalised ureteric stent registry for eliminating the potential for prolonged or forgotten ureteric stents.

  8. Coated stents to prevent restenosis in coronary heart disease

    Directory of Open Access Journals (Sweden)

    Hagen, Anja

    2005-11-01

    Full Text Available Background: In-stent-restenosis (ISR is considered to be an essential limiting factor of stenting in coronary heart disease (CHD. The development of coated stents has raised expectations on substantial lowering restenosis after stenting with decreasing the rate of restenosis and a reduction in the rate of clinical events. Objectives: The present analysis addresses the questions on medical effectiveness and cost-effectiveness of the use of various coated stent types in CHD. Methods: The literature was searched in December 2004 in the most relevant medical and economic databases. The medical evaluation was conducted on the basis of published RCT. The data from the studies regarding various angiographic, sonographic and clinical endpoints were checked for methodical quality and summarised in meta-analyses. Within the scope of economic evaluation the primary studies were analysed and modelling was performed, applying clinical effect estimates from the meta-analyses of the medical evaluation and current estimates of German costs. Results: Medical evaluation: Ten different stenttypes were used in the included 26 RCT. The results for heparin, silicon-carbide, carbon and PTFE coated stenttypes could not reveal any significant differences between the medical effectiveness of coated and uncoated stents. The application of sirolimus, paclitaxel, everolimus and 7-hexanoyltaxol eluting stents showed a significant lower restenosis at 6-9 months with decrease in the rate of restenosis for polymer-based sirolimus, paclitaxel and 7-hexanoyltaxol eluting stents. In contrast, the use of gold-coated and actinomycin-D eluting stents was associated with a significantly higher restenosis. The polymer-based sirolimus and paclitaxel eluting stents also showed a significant and considerable reduction in the rate of repeated percutaneous revascularisations at 6-12 months (3.5% vs. 19.7%; p<0.0001, RR=0.19 [95%CI: 0.11; 0.33] and 3.5% vs. 12.2%; p<0.0001, RR=0.30 [95%CI: 0

  9. Comparative Effectiveness of Carotid Artery Stenting Versus Carotid Endarterectomy Among Medicare Beneficiaries.

    Science.gov (United States)

    Jalbert, Jessica J; Nguyen, Louis L; Gerhard-Herman, Marie D; Kumamaru, Hiraku; Chen, Chih-Ying; Williams, Lauren A; Liu, Jun; Rothman, Andrew T; Jaff, Michael R; Seeger, John D; Benenati, James F; Schneider, Peter A; Aronow, Herbert D; Johnston, Joseph A; Brott, Thomas G; Tsai, Thomas T; White, Christopher J; Setoguchi, Soko

    2016-05-01

    Effectiveness of carotid artery stenting (CAS) relative to carotid endarterectomy (CEA) among Medicare patients has not been established. We compared effectiveness of CAS versus CEA among Medicare beneficiaries. We linked Medicare data (2000-2009) to the Society for Vascular Surgery's Vascular Registry (2005-2008) and the National Cardiovascular Data Registry's (NCDR) Carotid Artery Revascularization and Endarterectomy Registry (2006-2008/2009). Medicare patients were followed up from procedure date until death, stroke/transient ischemic attack, periprocedural myocardial infarction, or a composite end point for these outcomes. We derived high-dimensional propensity scores using registry and Medicare data to control for patient factors and adjusted for provider factors in a Cox regression model comparing CAS with CEA. Among 5254 Society for Vascular Surgery's Vascular Registry (1999 CAS; 3255 CEA) and 4055 Carotid Artery Revascularization and Endarterectomy Registry (2824 CAS; 1231 CEA) Medicare patients, CAS patients had a higher comorbidity burden and were more likely to be at high surgical risk (Society for Vascular Surgery's Vascular Registry: 96.7% versus 44.5%; Carotid Artery Revascularization and Endarterectomy Registry: 71.3% versus 44.7%). Unadjusted outcome risks were higher for CAS. Mortality risks remained elevated for CAS after adjusting for patient-level factors (hazard ratio, 1.24; 95% confidence interval, 1.06-1.46). After further adjustment for provider factors, differences between CAS and CEA were attenuated or no longer present (hazard ratio for mortality, 1.13; 95% confidence interval, 0.94-1.37). Performance was comparable across subgroups defined by sex and degree of carotid stenosis, but there was a nonsignificant trend suggesting a higher risk of adverse outcomes in older (>80) and symptomatic patients undergoing CAS. Outcomes after CAS and CEA among Medicare beneficiaries were comparable after adjusting for both patient- and provider

  10. Impact of lesion calcification on angiographic outcomes after Absorb everolimus-eluting bioresorbable vascular scaffold implantation: An observation from the ABSORB Japan trial

    NARCIS (Netherlands)

    Ohya, M. (Masanobu); K. Kadota (Kazushige); Y. Sotomi (Yohei); K. Kozuma (Ken); K. Tanabe (Kengo); Uematsu, M. (Masaaki); Kawasaki, T. (Tomohiro); Morino, Y. (Yoshihiro); Tobaru, T. (Tetsuya); Nakao, K. (Koichi); Tachibana, K. (Kouichi); Kishi, K. (Koichi); Shibata, Y. (Yoshisato); S. Ying (Shihwa); Kusano, H. (Hajime); G.W. Stone (Gregg); J.J. Popma (Jeffrey); Y. Onuma (Yoshinobu); P.W.J.C. Serruys (Patrick); T. Kimura (Takeshi)

    2017-01-01

    textabstractAims: We aimed to investigate the impact of lesion calcification on angiographic outcomes after Absorb everolimus-eluting bioresorbable vascular scaffold (BVS) implantation in comparison with those after cobalt-chromium everolimus-eluting stent (CoCr-EES) implantation. Methods and

  11. Endobiliary Stent Position Changes during External-beam Radiotherapy.

    Science.gov (United States)

    Chu, Kwun-Ye; Eccles, Cynthia L; Brunner, Thomas B

    2015-03-01

    Endobiliary stents can be used as surrogates for pancreatic localization when using cone-beam computed tomography (CBCT) during external-beam radiotherapy (EBRT). This work reports on interfraction stent position changes during EBRT for locally advanced pancreatic cancer (LAPC). Six patients with endobiliary stents who underwent EBRT for LAPC were assessed. Measurements from the most superior aspect of the stent (sup stent) and the most inferior aspect of the stent (inf stent) to the most inferior, posterior aspect of the L1 vertebra central spinous process were determined from daily treatment CBCTs and compared with those determined from the planning computed tomography (CT) scan. Changes in stent-L1 measurements were interpreted as changes in relative stent position. Three patients showed mean interfraction stent position changes of ≥1 cm when treatment measurements were compared with planning measurements. The sup stent for patient A moved to the right (2.66 ± 2.77 cm) and inferiorly (3.0 ± 3.12 cm), and the inf stent moved to the right (1.92 ± 2.02 cm) inferiorly (3.23 ± 3.34 cm) and posteriorly (1.41 ± 1.43 cm). The inf stent for patient B moved superiorly (2.23 ± 0.49 cm) and posteriorly (1.72 ± 0.59 cm). The sup and inf stent for patient F moved inferiorly (0.98 ± 0.35 cm and 1.21 ± 0.38 cm, respectively). The remaining three patients C, D, and E showed interfraction position changes of <1 cm. Endobiliary stent migration and deformation were observed in a small subset of patients. Further investigation is required before confirming their use as surrogates for LAPC target localization during image-guided EBRT.

  12. Intravascular sonotherapy decreases neointimal hyperplasia after stent implantation in swine.

    Science.gov (United States)

    Fitzgerald, P J; Takagi, A; Moore, M P; Hayase, M; Kolodgie, F D; Corl, D; Nassi, M; Virmani, R; Yock, P G

    2001-04-10

    Intimal hyperplasia and subsequent in-stent restenosis remain a major limitation after stent implantation. In vitro cell culture studies show that low-frequency, noncavitational ultrasound energy may impact smooth muscle cell proliferation. Accordingly, we assessed the efficacy of intravascular sonotherapy treatment on intimal hyperplasia in a swine stent model. After balloon injury, biliary stents (Johnson & Johnson) were implanted in the femoral arteries of 14 swine. A total of 48 stented sites were randomized to sonotherapy or sham treatment using a custom-built, 8-French catheter intravascular sonotherapy system (URX, PharmaSonics Inc). After stent deployment, ultrasound energy (700 KHz) was applied to the treatment group for up to 5 minutes. Smooth muscle cell proliferation was assessed using bromodeoxyuridine histology preparation (BrdU) at 7 days in 28 stented sites. At 28 days, the neointimal thickness and the ratio of neointimal/stent area (percent stenosis) was calculated by histomorphometric quantification in 20 stented sites. At 7 days, percent of BrdU staining was significantly reduced in the sonotherapy group compared with the sham group (24.1+/-7.0% versus 31.2+/-3.0%, Psonotherapy group than in the sham group (36+/-24% versus 44+/-27%, Psonotherapy group was less than in the sham group (417+/-461 micrometer versus 643+/-869 micrometer, P=0.06). In this swine peripheral model, intravascular sonotherapy seemed to decelerate cellular proliferation and decrease in-stent hyperplasia. Therefore, intravascular sonotherapy may be an effective form of nonionizing energy to reduce in-stent restenosis.

  13. Chest pain following oesophageal stenting for malignant dysphagia

    Energy Technology Data Exchange (ETDEWEB)

    Golder, Mark; Tekkis, Paris P.; Kennedy, Colette; Lath, Sadaf; Toye, Rosemary; Steger, Adrian C

    2001-03-01

    AIM: The palliative use of self-expanding metallic stents has been widely reported to relieve dysphagia in cases of oesophageal carcinoma. Little has been documented on the severity of chest pain following oesophageal stenting. The aim of this study was to investigate the association of pain with oesophageal stenting for malignant dysphagia. METHODS: Fifty-two patients with inoperable oesophageal carcinoma underwent stent placement between 1995-1999. Daily opioid analgesic requirements (mg of morphine equivalent doses) were monitored for 3 days before and 7 days after stenting. The degree of palliation was expressed as a dysphagia score (0-3). Hospital stay, readmission days, stent complications and patient survival time were also recorded. RESULTS: Twenty-six patients (50%) required opioid analgesia for chest pain (median dose: 80 mg morphine/day) within 48 h of the procedure compared to 11 (21.2%) patients before stenting (P = 0.0041). A significant increase was evident in the analgesic consumption following stent deployment (P < 0.001). The dysphagia score improved by a median value of 1 (CI 0.25)P < 0.001, with a re-intervention rate of 11.5%. The median survival time was 40 days post stenting (range 1-120). CONCLUSION: A significant proportion of patients developed chest pain after oesophageal stenting, requiring high dose opioid analgesia. As the origin of the pain is still unknown, pre-emptive analgesia may a play role in reducing stent-related morbidity and possibly in-hospital stay. Golder, M. et al. (2001)

  14. Radiation dosimetry in developing a radioactive stent for therapeutic use

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Eun Hee; Kim, Jang Hee; Chung, Wee Sup; Woo, Kwang Sun [Korea Cancer Center Hospital , Seoul (Korea, Republic of)

    1997-09-01

    Research Goal: A new radioation therapy protocol of the esophageal carcinoma has been proposed. A metal stent coated with beta-emitting radioisotope would be inserted into the lesion of malignant esophageal obstruction and irradiate it. In this study, dose to the esophageal wall is estimated to suggest the selection of radioisotope, total activity, and the activity distribution pattern over the stent. Result: Dose distribution of the esophageal wall is determined by the energy spectrum of beta particles emitted from the radioisotope used in the stent activation. The endpoint energy of the beta spectrum corresponds to a range in liquid water, which determines the depth into the esophageal wall where the dose is significant. With a stent of constant areal activity density, dose to the esophageal wall increases with an increasing stent height until reaching a saturation value. Dose is maximum at the esophageal wall surface. The degree of dose decreasing as the target moves into the esophageal wall varies among different radioisotopes. However, dose decreases by similar degree among different radioisotopes as the target moves from the stent central height toward the stent end. For a stent of 2 cm in diameter, more than 4 cm in heigh, and 10 {mu}Ci/cm{sup 2} in activity, dose at the esophageal wall surface and at the stent central height is {approx}70 Gy, {approx}60 Gy, {approx}50 Gy, {approx}50 Gy, {approx}25 Gy, and {approx}15 Gy for {sup 90}Y, {sup 188}Re, {sup 166}Ho, {sup 32}P, {sup 186}Re, and {sup 192}Ir, respectively. Applications: Dose estimates provided in this study and the experimental results from the researchers at Yonsei University, who applied the radioactive stent to animals, will be used to analyze the relationship between the stent design and the corresponding therapeutic effect. This helps utilizing the new protocol of treating the esophageal carcinoma. 37 refs., 18 tabs., 27 figs. (author)

  15. Biological Functional Relevance of Asymmetric Dimethylarginine (ADMA in Cardiovascular Disease

    Directory of Open Access Journals (Sweden)

    Sara Franceschelli

    2013-12-01

    Full Text Available There is growing evidence that increased levels of the endogenous NO synthase inhibitor asymmetric dimethylarginine (ADMA may contribute to endothelial dysfunction. Studies in animal models as well as in humans have suggested that the increase in ADMA occurs at a time when vascular disease has not yet become clinically evident. ADMA competitively inhibits NO elaboration by displacing L-arginine from NO synthase. In a concentration-dependent manner, it thereby interferes not only with endothelium-dependent, NO-mediated vasodilation, but also with other biological functions exerted by NO. The upshot may be a pro-atherogenic state. Recently, several studies have investigated the effect of various therapeutical interventions on ADMA plasma concentrations.

  16. Construction of a fucoidan/laminin functional multilayer to direction vascular cell fate and promotion hemocompatibility

    Energy Technology Data Exchange (ETDEWEB)

    Ye, Changrong; Wang, Yan; Su, Hong; Yang, Ping; Huang, Nan [Key Laboratory of Advanced Materials Technology of Ministry of Education, Department of Materials Science and Engineering, Southwest Jiaotong University, Chengdu 610031 (China); Maitz, Manfred F. [Leibniz Institute of Polymer Research Dresden, Max Bergmann Center of Biomaterials Dresden, Dresden 01069 (Germany); Zhao, Anshan [Key Laboratory of Advanced Materials Technology of Ministry of Education, Department of Materials Science and Engineering, Southwest Jiaotong University, Chengdu 610031 (China)

    2016-07-01

    Surface biofunctional modification of cardiovascular stents is a versatile approach to reduce the adverse effects after implantation. In this work, a novel multifunctional coating was fabricated by coimmobilization of the sulfated polysaccharide of brown algae fucoidan and laminin to biomimic the vascular intimal conditions in order to support rapid endothelialization, prevent restenosis and improve hemocompatibility. The surface properties of the coating such as hydrophilicity, bonding density of biomolecules and stability were evaluated and optimized. According to the biocompatibility tests, the fucoidan/laminin multilayer coated surface displayed less platelet adhesion with favorable anticoagulant property. In addition, the fucoidan/laminin complex showed function to selectively regulate vascular cells growth behavior. The proliferation of endothelial cells (ECs) on the fucoidan/laminin biofunctional coating was significantly promoted. For the smooth muscle cells (SMCs), inhibitory effects on cell adhesion and proliferation were observed. In conclusion, the fucoidan/laminin biofunctional coating was successfully fabricated with desirable anticoagulant and endothelialization properties which show a promising application in the vascular devices such as vascular stents or grafts surface modification. - Highlights: • Construction of fucoidan/laminin functional multilayer to biomimic the basement membrane of vascular • The fucoidan/laminin complex demonstrates anti-coagulation property. • The fucoidan/laminin complex can selectively regulate EC and SMC growth behavior to prevent restenosis.

  17. [Cerebral vascular accidents after cardiac catheterization in patients with anamnesis of stroke].

    Science.gov (United States)

    Zhang, Hua; Zhang, Zhuo

    2007-10-09

    To investigate the risk factors of relapse of cerebral vascular accident (CVA) after cardiac catheterization (CC) in patients with anamnesis stroke. The clinical data of 892 patients with anamnesis stroke who received cardiac catheterization (CC) from Jan. 2002 to Oct. 2006, 555 males and 337 females, aged 61 +/- 10, were analyzed retrospectively. 101 of the 892 patients (11.32%) suffered from CVA during the procedure of CC or within 24 hours after the operation, including 33 cases of transient ischemic attack (TIA), 64 cases of cerebral infarction (CI) and 4 cases of cerebral hemorrhage (CH). Logistic regression analysis showed that the risk factors of relapse of CVA after CC included male gender (OR = 0.308, 95% CI = 0.141 - 0.674), alcohol consumption (OR = 0.319, 95% CI = 0.128 - 0.797), hyperlipidemia (OR = 3.676, 95% CI = 1.94 - 6.950), peripheral vascular diseases (OR = 7.419, 95% CI = 2.477 - 22.219), and number of cardiac vascular diseases (OR = 1.809, 95% CI = 1.284 - 2.548). The patients undergoing percutaneous transluminal coronary angioplasty (PTCA) and stenting were much more liable to CVA compared with the other patients. The risk factors of relapse of CVA after CC include male gender, alcohol consumption, hyperlipidemia, peripheral vascular diseases, number of cardiac vascular diseases, and the procedures of PTCA and stenting.

  18. Clinical outcomes after heterogeneous overlap stenting with drug-eluting stents and bare-metal stents for de novo coronary artery narrowings.

    Science.gov (United States)

    Aoki, Jiro; Kirtane, Ajay J; Dangas, George D; Lansky, Alexandra J; Morales, Andy; Kimura, Masashi; Kim, Young-Hak; Moussa, Issam; Weisz, Giora; Kreps, Edward M; Collins, Michael; Frankin-Bond, Theresa; Stone, Gregg W; Moses, Jeffrey W; Leon, Martin B; Mehran, Roxana

    2008-01-01

    When it is difficult to deliver multiple drug-eluting stents (DES) or when size constraints limit DES implantation, bare-metal stents (BMS) may be implanted contiguous to DES. However, the clinical outcomes after overlapping DES and BMS implantation are not known. From September 2004 to June 2006, 4,872 consecutive patients who underwent percutaneous coronary intervention consented to be enrolled in a prospective registry. Of these patients, 44 (0.9%) with de novo lesions were treated with DES and BMS overlap stenting. All patients were followed to 12 months for the assessment of clinical outcomes. The average implanted stent diameter was 2.68 +/- 0.30 mm for DES and 2.35 +/- 0.38 mm for BMS. Overlapping BMS were implanted distal to DES in all but 1 case. One patient (2.3%) experienced acute stent thrombosis and died 2 days after the procedure. No other patient died or had a myocardial infarction during 12 months. The target vessel revascularization rate at 12 months, however, was 31.8%, mainly driven by diffuse in-stent restenosis in the BMS segments. In conclusion, the incidence of DES and BMS overlap stenting is rare in daily practice, but this procedure is associated with a high rate of target vessel revascularization.

  19. Asymmetric Warfare and the Will to Win

    National Research Council Canada - National Science Library

    Herrera, Cary

    2001-01-01

    This thesis explores the will to win in asymmetric war. Asymmetric war, in which one side has an overwhelming advantage over its opponent, will likely be the war of the future for the United States in the post-Cold War uni-polar world...

  20. Renewable resource management under asymmetric information

    DEFF Research Database (Denmark)

    Jensen, Frank; Andersen, Peder; Nielsen, Max

    2013-01-01

    Asymmetric information between fishermen and the regulator is important within fisheries. The regulator may have less information about stock sizes, prices, costs, effort, productivity and catches than fishermen. With asymmetric information, a strong analytical tool is principal-agent analysis. I...

  1. Asymmetric Quantum Codes on Toric Surfaces

    DEFF Research Database (Denmark)

    Hansen, Johan P.

    2017-01-01

    Asymmetric quantum error-correcting codes are quantum codes defined over biased quantum channels: qubit-flip and phase-shift errors may have equal or different probabilities. The code construction is the Calderbank-Shor-Steane construction based on two linear codes. We present families of toric...... surfaces, toric codes and associated asymmetric quantum error-correcting codes....

  2. Mechanochemistry assisted asymmetric organocatalysis: A sustainable approach

    OpenAIRE

    Chauhan, Pankaj; Chimni, Swapandeep Singh

    2012-01-01

    Summary Ball-milling and pestle and mortar grinding have emerged as powerful methods for the development of environmentally benign chemical transformations. Recently, the use of these mechanochemical techniques in asymmetric organocatalysis has increased. This review highlights the progress in asymmetric organocatalytic reactions assisted by mechanochemical techniques.

  3. Mechanochemistry assisted asymmetric organocatalysis: A sustainable approach

    Science.gov (United States)

    Chauhan, Pankaj

    2012-01-01

    Summary Ball-milling and pestle and mortar grinding have emerged as powerful methods for the development of environmentally benign chemical transformations. Recently, the use of these mechanochemical techniques in asymmetric organocatalysis has increased. This review highlights the progress in asymmetric organocatalytic reactions assisted by mechanochemical techniques. PMID:23243475

  4. Worst Asymmetrical Short-Circuit Current

    DEFF Research Database (Denmark)

    Arana Aristi, Iván; Holmstrøm, O; Grastrup, L

    2010-01-01

    In a typical power plant, the production scenario and the short-circuit time were found for the worst asymmetrical short-circuit current. Then, a sensitivity analysis on the missing generator values was realized in order to minimize the uncertainty of the results. Afterward the worst asymmetrical...

  5. Mechanochemistry assisted asymmetric organocatalysis: A sustainable approach

    Directory of Open Access Journals (Sweden)

    Pankaj Chauhan

    2012-12-01

    Full Text Available Ball-milling and pestle and mortar grinding have emerged as powerful methods for the development of environmentally benign chemical transformations. Recently, the use of these mechanochemical techniques in asymmetric organocatalysis has increased. This review highlights the progress in asymmetric organocatalytic reactions assisted by mechanochemical techniques.

  6. Expression and function of calcium-activated potassium channels following in-stent restenosis in a porcine coronary artery model

    Directory of Open Access Journals (Sweden)

    Mais F. Absi

    2012-04-01

    Functional analysis using 1-EBIO and Bradykinin produced hyperpolarization of neointimal but not medial myocytes, which indicated the expression of functional endothelial SK3 and IKCa in the former and not in the latter. The expression of IKCa and SK3 within the neointimal layer suggested that some degree of recovery of both endothelial as well as smooth muscle regeneration had occurred. Future development of selective modulators of IKCa and SK3 channels may decrease the progression of ISR and improve coronary vascular function after stent placement, and is an area for future investigation.

  7. Outcomes of polytetrafluoroethylene-covered stent versus bare-metal stent in the primary treatment of severe iliac artery obstructive lesions.

    Science.gov (United States)

    Piazza, Michele; Squizzato, Francesco; Spolverato, Gaya; Milan, Luca; Bonvini, Stefano; Menegolo, Mirko; Grego, Franco; Antonello, Michele

    2015-11-01

    This study compared early and midterm outcomes of polytetrafluoroethylene-covered stents (CSs) vs bare-metal stents (BMSs) in the primary treatment of severe TransAtlantic Inter-Society Consensus for the Management of Peripheral Arterial Disease (TASC II) C and D iliac artery obstructive lesions. Between January 2009 and June 2014, 128 patients underwent stenting of 167 iliac arteries; CSs were implanted in 82 iliac arteries (49%) and BMSs in 85 (51%). All patients were prospectively enrolled in a dedicated database. Thirty-day outcomes, mid-term patency, limb salvage, and survival were compared, and follow-up results were analyzed with Kaplan-Meier curves. Clinical presentation, lesion site, extension, and laterality were evaluated for their association with patency in the two groups using multiple logistic regressions. Patients were a mean age of 70 ± 10.3 years, The Society for Vascular Surgery comorbidity score was 0.89 ± 0.57, with no differences after stratification by CS and BMS (P = .17). Iliac lesions were classified by limb as TASC II C in 86 (51%) and D in 81 (49%). Comparing CS and BMS, technical success was 99% in both groups (P = 1.0); the 30-day cumulative surgical complications rate (7.3% vs 4.7%; P = .53), mortality (1.8% vs 0%; P = .45), and morbidity (1.8% vs 1.4%; P = .99) were equivalent. At 24 months (average 22 months; range, 30 days-56 months), primary patency of CS vs BMS was similar (93% vs 80%; P = .14), and this finding was maintained after stratification by TASC II C (97% vs 93%; P = .59) and D (88% vs 61%; P = .07); secondary patency was 98% vs 92% (P = .22), and limb salvage was 99% and 95% (P = .35) respectively. Multivariate analysis indicated that BMS in long-segment stenosis involving the common and external iliac arteries was a negative predictor of patency (odds ratio, 0.16; 95% confidence interval, 0.04-0.62; P = .007); within this subgroup of TASC II D lesions, primary patency at 24 months was significantly

  8. [Asymmetric dimethylarginine (ADMA) in children with diabetes type 1].

    Science.gov (United States)

    Głowińska-Olszewska, Barbara; Luczyński, Włodzimierz; Jabłońska, Jolanta; Otocka, Agnieszka; Florys, Bożena; Bossowski, Artur

    2010-01-01

    Asymmetric dimethylarginine (ADMA), a naturally occurring product of asymmetric methylation of proteins, is an endogenous inhibitor of endothelial nitric oxide synthase. ADMA is now recognized as an independent marker of endothelial dysfunction and atherosclerosis. Data concerning ADMA level in type 1 diabetes (DM1) are controversial. The aim of the study was to evaluate ADMA level in children with DM1, without clinical evidence of vascular complications, with particular attention to additional cardiovascular risk factors (hypertension, obesity, hyperlipidemia). The study group included 72 children with DM1, aged mean 15±3 yrs (8-20 yrs), 33 boys and 39 girls, with diabetes duration time mean 6.6±3.5 yrs (1-14 yrs), HBA1c mean level 8.2±2.3% (5.6-15%). The control group consisted of 41 (19 boys and 22 girls) healthy children, aged mean--14.8±2.6 yrs, from 8 to 18 yrs, gender matched, with no family history of cardiovascular disease. ADMA level was determined in plasma using ELISA kit (DLD Diagnostica, Hamburg, Germany) ADMA level was similar in children with diabetes and in the control group: 0.69±0.33 vs. 0.7±0.27 μmol/L, ns. We did not find differences in ADMA level in diabetic children with the presence of additional diseases being cardiovascular risk factors. In the group of 13 children with hypertension ADMA level was the highest: 0.79±0.25 μmol/L, but the difference was statistically insignificant in comparison to children with diabetes without hypertension and in comparison to healthy controls. Children with DM1, without clinically evident vascular complications, have ADMA levels similar to healthy children. A possible relationship between ADMA and hypertension in these patients requires further investigation.

  9. Stent thrombosis: incidence and related factors in the R.I.S.E. Registry(Registro Impianto Stent Endocoronarico)

    Science.gov (United States)

    De Servi, S; Repetto, S; Klugmann, S; Bossi, I; Colombo, A; Piva, R; Giommi, L; Bartorelli, A; Fontanelli, A; Mariani, G; Klersy, C

    1999-01-01

    Although stent thrombosis has been greatly reduced by adequate stent expansion with high-pressure balloon inflations and by the use of antiplatelet drugs, this event is still frightening, as it may lead to acute myocardial ischemia resulting in acute myocardial infarction or sudden death. Therefore, the definition of factors associated with stent thrombosis may provide a better understanding of the mechanisms underlying this phenomenon and may permit us to define therapeutic strategies to further reduce its occurrence. The purpose of this study was to assess factors responsible for the occurrence of stent thrombosis after coronary stent implantation in 939 consecutive patients enrolled in the Registro Impianto Stent Endocoronarico (R.I.S.E. Study Group). Consecutive patients undergoing coronary stent implantation at 16 medical centers in Italy were prospectively enrolled in the registry. Clinical data, and qualitative and quantitative angiographic findings were obtained from data collected in case report forms at each investigator site. The study group consisted of 781 men and 158 women with a mean age of 59 yr: 1,392 stents were implanted in 1,006 lesions and expanded at a maximal inflation pressure of 14.7 +/- 3 atm. The great majority of patients (92%) received only antiplatelet drugs after coronary stenting. During hospitalization there were 45 major ischemic complications in 39 patients (4.2%): 13 events were related to acute or subacute thrombosis (1.4%). Another stent thrombotic event occurred in the first month of follow-up. On multivariate logistic regression analysis, stent thrombosis was related to the following factors: unplanned stenting (OR 3.46, 95% CI 1.65-7.23), unstable angina (OR 3.37, 95% CI 1.11-10.14) and maximal inflation pressure (OR 0.83, 95% CI 0.75-0.93). In conclusion, this registry shows that in an unselected population of patients undergoing coronary stenting, stent thrombosis occurs in less than 2% of patients and is significantly

  10. Next-generation drug-eluting stents in coronary artery disease: focus on everolimus-eluting stent (Xience V).

    Science.gov (United States)

    Sheiban, Imad; Villata, Gianluca; Bollati, Mario; Sillano, Dario; Lotrionte, Marzia; Biondi-Zoccai, Giuseppe

    2008-01-01

    Percutaneous coronary revascularization has been a mainstay in the management of coronary artery disease since its introduction in the late 1970s. Bare-metal stents and, more recently, first-generation drug-eluting stents (DES), such as sirolimus-eluting (Cypher) and paclitaxel-eluting stents (Taxus), have further improved results of percutaneous coronary intervention (PCI) by improving early results and reducing the risk of restenosis. There is currently debate on the safety of these first-generation DES, given the potential for late stent thrombosis, especially after discontinuation of dual antiplatelet therapy. There are well known caveats on the performance of their respective metallic stent platforms, delivery, and dilation systems, and polymer coatings. Second-generation DES, such as zotarolimus-eluting (Endeavor) and everolimus-eluting stents (Xience V), have recently become available in the USA and/or Europe. The Xience V stent holds the promise of superior anti-restenotic efficacy as well as long-term safety. In addition, this stent is based on the Multi-link platform and delivery system. Recently available data already suggest the superiority of the Xience V stent in comparison to the Taxus stent in terms of prevention of restenosis, without significant untoward events. Nonetheless, the number of patients studied and the follow-up duration are still too limited to enable definitive conclusions. Only indirect meta-analyses can be used to date to compare the Xience V with the Cypher. This systematic review tries to provide a concise and critical appraisal of the data in support of the Xience V everolimus-eluting stent.

  11. Next-generation drug-eluting stents in coronary artery disease: focus on everolimus-eluting stent (Xience V®)

    Science.gov (United States)

    Sheiban, Imad; Villata, Gianluca; Bollati, Mario; Sillano, Dario; Lotrionte, Marzia; Biondi-Zoccai, Giuseppe

    2008-01-01

    Percutaneous coronary revascularization has been a mainstay in the management of coronary artery disease since its introduction in the late 1970s. Bare-metal stents and, more recently, first-generation drug-eluting stents (DES), such as sirolimus-eluting (Cypher®) and paclitaxel-eluting stents (Taxus®), have further improved results of percutaneous coronary intervention (PCI) by improving early results and reducing the risk of restenosis. There is currently debate on the safety of these first-generation DES, given the potential for late stent thrombosis, especially after discontinuation of dual antiplatelet therapy. There are well known caveats on the performance of their respective metallic stent platforms, delivery, and dilation systems, and polymer coatings. Second-generation DES, such as zotarolimus-eluting (Endeavor®) and everolimus-eluting stents (Xience V®), have recently become available in the USA and/or Europe. The Xience V stent holds the promise of superior anti-restenotic efficacy as well as long-term safety. In addition, this stent is based on the Multi-link platform and delivery system. Recently available data already suggest the superiority of the Xience V stent in comparison to the Taxus stent in terms of prevention of restenosis, without significant untoward events. Nonetheless, the number of patients studied and the follow-up duration are still too limited to enable definitive conclusions. Only indirect meta-analyses can be used to date to compare the Xience V with the Cypher. This systematic review tries to provide a concise and critical appraisal of the data in support of the Xience V everolimus-eluting stent. PMID:18629361

  12. A new stent design with multiple radio-opaque markers for protection of side-branch vessels in bifurcation lesions: HJ stents.

    Science.gov (United States)

    Hong, Myeong-Ki; Kim, Jung-Sun; Kim, Byeong-Keuk; Ko, Young-Guk; Choi, Donghoon; Jang, Yangsoo

    2011-01-01

    Loss of side-branch vessels is a serious complication following stent implantation in parent vessels of bifurcation lesions. The purpose of this study was to introduce and test a new stent design for the protection of side-branch vessels in the management of bifurcation lesions. This stent has multiple radio-opaque markers in its central portion, whose presence is useful in avoiding stent-strut placement across the side-branch orifice and in correctly directing the insertion of a second guide wire through the struts into the side branch to minimize jailing of side branches during stent deployment in the parent vessel. In vitro tests of the acrylic resin bifurcation phantom model were performed under fluoroscopic guidance in the catheterization laboratory with 10 stents with multiple radio-opaque markers and 10 stents without. Kissing balloon angioplasty was performed across the side branch after stent implantation in the parent vessel in both groups. Side-branch jailing by the stent (presence of any stent struts crossing the side-branch orifice) was determined visually and compared between the two groups. The jailed side branch with the stent struts was observed in one of 10 new stents and in five of 10 conventional stents without them. The in vitro tests demonstrated the superiority of a new stent design for the reduction of side-branch jailing in bifurcation lesions. Copyright © 2011 Elsevier Inc. All rights reserved.

  13. Effects of 308 nanometer excimer laser energy on 316 L stainless-steel stents: implications for laser atherectomy of in-stent restenosis.

    Science.gov (United States)

    Burris, N; Lippincott, R A; Elfe, A; Tcheng, J E; O'Shea, J C; Reiser, C

    2000-11-01

    To determine the effects of the incidental exposure of stents to pulsed 308 nanometer ultraviolet excimer laser energy. Five types of 316 L stainless-steel coronary stents were subjected to two types of study. First, for endurance testing, sixty stents were deployed in 3.0Eth 4.0 mm polymer tubes in three geometries. Up to 1,000 laser pulses were delivered while advancing a 2.0 mm eccentric catheter through the lumen of the stent. These stents were next subjected to 400 million simulated heartbeats and then analyzed for metal etching and fatigue. Second, six additional stents were irradiated with 1,000 pulses underwater and then analyzed for particulates, anions and cations liberated from the stent. Photomicroscopy revealed surface etching on a number of stents. Two stent models exhibited multiple strut fractures at the strut joints in both test samples and controls. In no case was a break observed at the site of laser-stent interaction. Breakage frequency was not significantly different between lazed stents and controls. Lazed stents produced a mean of 14 micrograms of sodium and 4 micrograms of iron more than controls. No excess particulates were detected. Under model conditions typical of clinical use, excimer laser treatment does not alter stainless-steel stent endurance or liberate clinically significant material from the stent.

  14. Asymmetric Digital Subscriber Line (ADSL

    Directory of Open Access Journals (Sweden)

    Slavko Šarić

    2012-10-01

    Full Text Available ADSL (Asymmetric Digital Subscriber Line is a technologythat allows transmission at 8.488 Mbps over the existingtelephone copper line (speed range depending on the distance.ADSL circuit connects the ADSL modems by twisted-pairtelephone lines creating three infonnation channels: high speedsimplex (maximum 9 Mbps, medium speed duplex channel(maximum 2 Mbps and plain old telephone service channel.ADSL technology supports up to seven synchronous channelsthat can be configured to meet the needs of the end user.One could simultaneously view four movies stored in MPEG 1fonnat on separate television sets (MPEG 1 transmitted at 1.5Mbps, hold a video-conference (transmitted at 348 kbps,download data files from a server at 128 kbps via ISDN andeven receive a telephone call.

  15. Research on asymmetric searchable encryption

    Science.gov (United States)

    Yu, Zonghua; Wu, Yudong

    2017-05-01

    Cloud server side to ease the user's local storage pressure at the same time, there are hidden data on the hidden dangers, the user often choose to upload the data in the form of cipher text to the cloud server. However, the classic data encryption and decryption algorithms are not provided search function, affecting the user's efficiency. To this end, an asymmetric searchable encryption scheme is proposed. The scheme can be used for any person can generate a trapdoor, cipher text can be free modified, the key pair generated by the user themselves, encrypt the identity, S-shaped virtual and other five loopholes to improve. The analysis results show that the scheme solves the above five vulnerabilities in the original scheme, so that the information semantics of both parties of communication can be guaranteed.

  16. Overlapped Stenting Combined with Coiling for Blood Blister-Like Aneurysms: Comparison of Low-Profile Visualized Intraluminal Support (LVIS) Stent and Non-LVIS Stent.

    Science.gov (United States)

    Zhu, Deyuan; Fang, Yibin; Yang, Pengfei; Zhang, Ping; Chen, Lei; Xu, Yi; Hong, Bo; Huang, Qinghai; Liu, Jian-Min

    2017-08-01

    To evaluate the safety and efficacy of overlapped stenting for blood blister-like aneurysms (BBAs) and to compare the outcomes between Low-profile Visualized Intraluminal Support (LVIS) and non-LVIS stents. A retrospective review of the aneurysm database identified 37 patients with intracranial carotid artery BBAs treated by overlapped stenting in our institution from June 2013 to June 2016. The clinical characteristics and angiographic results were reviewed. Overlapped stenting combined with coiling were applied in 37 BBAs, including LVIS stents in 18 cases and non-LVIS stents in 19. For the LVIS group, angiographic results at 3-24 months were complete occlusion in 15 cases (83.3%), improved in 2 cases (11.1%), and recanalized in 1 case (5.6%). The modified Rankin Scale scores at 3-36 months' follow-up were 0-2 in 15 cases (83.3%) and 3-6 in 3 cases (16.7%). For the non-LVIS group, angiographic results at 3-46 months were complete occlusion in 12 cases (63.2%) and recanalized in 7 cases (36.8%). Clinical outcomes at 6-58 months were modified Rankin Scale scores of 0-2 in 17 cases (89.5%) and 3-6 in 2 cases (10.5%). Use of the LVIS stent was less likely to result in recanalization (odds ratio 0.10, 95% confidence interval 0.01-0.93, P = 0.042) than the non-LVIS stent. The LVIS group had a lower average number of stents than did the non-LVIS group (2.2 vs. 2.6, P = 0.016). In terms of complication rate (11.1% vs. 5.3%, P = 0.604), good outcome rate (83.3% vs. 89.5%, P = 0.660), and immediate angiographic result (P = 0.424), no statistically significant difference between the 2 groups was found. Overlapped LVIS stenting combined with coiling is feasible and safe for BBAs. Overall, the LVIS stent provided less risk of BBA recurrence compared with the non-LVIS stent and did not increase the risk of procedure-related complications. Copyright © 2017 Elsevier Inc. All rights reserved.

  17. Transhepatic approach for extracardiac inferior cavopulmonary connection stent fenestration.

    LENUS (Irish Health Repository)

    Kenny, Damien

    2012-02-01

    We report on a 3-year-old male who underwent transcatheter stent fenestration of the inferior portion of an extracardiac total cavopulmonary connection in the setting of hypoplastic left heart syndrome. Transhepatic approach, following an unsuccessful attempt from the femoral vein facilitated delivery of a diabolo-shaped stent.

  18. Drug Eluting Stents for Symptomatic Intracranial and Vertebral Artery Stenosis

    OpenAIRE

    Fields, J.D.; Petersen, B.D.; Lutsep, H.L.; Nesbit, G.M.; K. C. Liu; Dogan, A; Lee, D S; Clark, W. M.; Barnwell, S L

    2011-01-01

    The use of bare metal stents (BMS) to prevent recurrent stroke due to stenosis of the cerebral vasculature is associated with high rates of restenosis. Drug-eluting stents (DES) may decrease this risk. We evaluated the performance of DES in a cohort of patients treated at our institution.

  19. Coronary bifurcation lesions treated with simple or complex stenting

    DEFF Research Database (Denmark)

    Behan, Miles W; Holm, Niels R; de Belder, Adam J

    2016-01-01

    AIMS: Randomized trials of coronary bifurcation stenting have shown better outcomes from a simple (provisional) strategy rather than a complex (planned two-stent) strategy in terms of short-term efficacy and safety. Here, we report the 5-year all-cause mortality based on pooled patient-level data...

  20. Late thrombosis of coronary bare-metal stent: Case report

    Directory of Open Access Journals (Sweden)

    Apostolović Svetlana

    2006-01-01

    Full Text Available Stent thrombosis remains the primary cause of death after percutaneous coronary interventions (PCI. Despite modern concepts of PCI, stent thrombosis occurs in 0.5% -2% of elective procedures and even 6% of patients with the acute coronary syndrome (ACS.