The Experts below are selected from a list of 303 Experts worldwide ranked by ideXlab platform
Peter Barlis - One of the best experts on this subject based on the ideXlab platform.
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an optical coherence tomography study of a biodegradable vs durable polymer coated limus eluting stent a leaders trial sub study
European Heart Journal, 2010Co-Authors: Peter Barlis, Giuseppe Ferrante, Willem J. Giessen, Patrick W.j.c. Serruys, Evelyn Regar, Robert-jan Van Geuns, Konstantinos Dimopoulos, Simon Wandel, Stephan Windecker, Pedro EerdmansAbstract:Aims Incomplete endothelialization has been found to be associated with late stent thrombosis, a rare but devastating phenomenon, more frequent after drug-eluting stent implantation. Optical coherence tomography (OCT) has 10 times greater resolution than intravascular ultrasound and thus appears to be a valuable modality for the assessment of stent Strut coverage. The LEADERS trial was a multi-centre, randomized comparison of a biolimus-eluting stent (BES) with biodegradable polymer with a sirolimus-eluting stent (SES) using a durable polymer. This study sought to evaluate tissue coverage and apposition of stents using OCT in a group of patients from the randomized LEADERS trial. Methods and results Fifty-six consecutive patients underwent OCT during angiographic follow-up at 9 months. OCT images were acquired using a non-occlusive technique at a pullback speed of 3 mm/s. Data were analysed using a Bayesian hierarchical random-effects model, which accounted for the correlation of lesion characteristics within patients and implicitly assigned analytical weights to each lesion depending on the number of Struts observed per lesion. Primary outcome was the difference in percentage of uncovered Struts between BESs and SESs. Twenty patients were included in the analysis in the BES group (29 lesions with 4592 Struts) and 26 patients in the SES group (35 lesions with 6476 Struts). A total of 83 Struts were uncovered in the BES group and 407 out of 6476 Struts were uncovered in the SES group [weighted difference −1.4%, 95% confidence interval (CI) −3.7 to 0.0, P = 0.04]. Results were similar after adjustment for pre-procedure lesion length, reference vessel diameter, number of implanted study stents, and presence of stent overlap. There were three lesions in the BES group and 15 lesions in the SES group that had ≥5% of all Struts uncovered (difference −33.1%, 95% CI −61.7 to −10.3, P < 0.01). Conclusion Strut coverage at an average follow-up of 9 months appears to be more complete in patients allocated to BESs when compared with SESs. The impact of this difference on clinical outcome and, in particular, on the risk of late stent thrombosis is yet to be determined.
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the influence of Strut thickness and cell design on immediate apposition of drug eluting stents assessed by optical coherence tomography
International Journal of Cardiology, 2009Co-Authors: Jun Tanigawa, Konstantinos Dimopoulos, Peter Barlis, Miles Dalby, Philip Moore, Carlo Di MarioAbstract:Abstract Background Stent Strut malapposition correlates with poor intimal coverage and this may increase the risk of late stent thrombosis. At present, there is limited data on whether stent Strut thickness and stent design impact on acute apposition. We aimed to investigate the influence of stent Strut thickness and design on acute stent Strut apposition (SSA) immediately following drug-eluting stent (DES) implantation using optical coherence tomography (OCT), a technique with higher resolution and fewer artefacts than intravascular ultrasound. Methods Thirty-six DES in 23 patients (25 lesions) were studied by OCT. SSA was defined as embedded when a Strut was buried in the intima for more than half its thickness, protruding when apposed to the intima but not embedded and malapposed when there was no intimal contact. Results Cypher Select stents were implanted in 52%, Taxus Liberte in 32%, Costar in 12% and Endeavour in 4%. A total of 6402 Struts were evaluated. Despite stent optimisation using balloons with a final balloon/artery ratio of 1.26±0.19 at a maximum inflation pressure of 17.5±3.0 atm, only 57.1±20.7% of Struts were embedded, whereas 33.8±18.4% were protruding and 9.1±7.4% were malapposed. Stent type was a strong predictor of malapposition on logistic multilevel analysis (OR 3.95, 95%CI: 1.27–12.23, p =0.017). At 12 months follow-up, there were no adverse clinical events. Conclusion Despite angiographic optimisation with high pressures and adequately sized balloons, malapposed stent Struts are frequently found in complex coronary lesions and more often following the implantation of Cypher Select stents which have a thicker stent Strut and closed cell design. With no adverse clinical events at 12 months follow-up, this likely represents a benign phenomenon at least as long as combined anti-platelet therapy is maintained.
Mariusz Tomaniak - One of the best experts on this subject based on the ideXlab platform.
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the ultra thin Strut sirolimus eluting coronary stent supraflex
Future Cardiology, 2021Co-Authors: Chao Gao, Rodrigo Modolo, Kuniaki Takahashi, Norihiro Kogame, Rutao Wang, Hideyuki Kawashima, Masafumi Ono, Hironori Hara, Mariusz TomaniakAbstract:Percutaneous coronary interventions with drug-eluting stents is currently the preferred revascularization treatment strategy for coronary artery disease. Following the first generation, the second-generation drug-eluting stents was designed with a thinner Strut, better biocompatible polymer with/without bioresorbable coating or even polymer-free Struts. The SUPRAFLEX stent system has ultra-thin Struts (60 μm) across all stent diameters and a biodegradable polymer coating, enabling 70% of the sirolimus elution within 7 days. SUPRAFLEX has been assessed in large scale randomized controlled trials. This review summarizes the design of the SUPRAFLEX stent, the results of the pivotal clinical trials and outlines the ongoing research programs.
Teppei Oda - One of the best experts on this subject based on the ideXlab platform.
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Shockwave effects on supersonic combustion using hypermixer Struts
Physics of Fluids, 2020Co-Authors: Toshihiko Hiejima, Teppei OdaAbstract:This study describes combustion features due to streamwise vorticity when using hypermixer Struts at Mach numbers of 2.5 and 3.5. Two types of Struts are used with hydrogen fuel (at an equivalence ratio of 0.4) injected at sonic speed from the trailing edges of the Struts. To study the effects of shockwaves on streamwise vorticity formation and supersonic combustion for an alternating-wedge Strut, the intersection point at which the shockwaves cross the central axis is varied by changing the length of the Strut. When the incident shock is near the trailing edge of the Strut, boundary-layer separation occurs on the ramp of the Strut due to pressure increase near the Strut and subsonic combustion occurs on the basis of this separation. Conversely, when the incident shock is far from the trailing edge of the Strut, a streamwise vortex is generated by the Strut and supersonic combustion caused by this vortex makes it effective at entraining fuel into itself. Each flame structure obtained here unquestionably differs in its combustion mode. For a separation-resistant Strut, the results show that a streamwise vortex with the required circulation can be induced behind the Strut without separation. Moreover, the combustion depends strongly on the incident shockwaves in that the combustion efficiency is not subject to the mixing efficiency because the moderate combustion originates near the point at which the formed streamwise vortex interacts with the shockwaves. Therefore, because an ignition point with moderate combustion can detach from its trailing edge, with a separation-resistant Strut, it is possible to control the combustion and avoid an excessive heat load.
Rodrigo Modolo - One of the best experts on this subject based on the ideXlab platform.
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the ultra thin Strut sirolimus eluting coronary stent supraflex
Future Cardiology, 2021Co-Authors: Chao Gao, Rodrigo Modolo, Kuniaki Takahashi, Norihiro Kogame, Rutao Wang, Hideyuki Kawashima, Masafumi Ono, Hironori Hara, Mariusz TomaniakAbstract:Percutaneous coronary interventions with drug-eluting stents is currently the preferred revascularization treatment strategy for coronary artery disease. Following the first generation, the second-generation drug-eluting stents was designed with a thinner Strut, better biocompatible polymer with/without bioresorbable coating or even polymer-free Struts. The SUPRAFLEX stent system has ultra-thin Struts (60 μm) across all stent diameters and a biodegradable polymer coating, enabling 70% of the sirolimus elution within 7 days. SUPRAFLEX has been assessed in large scale randomized controlled trials. This review summarizes the design of the SUPRAFLEX stent, the results of the pivotal clinical trials and outlines the ongoing research programs.
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the impact of plaque type on Strut embedment protrusion and shear stress distribution in bioresorbable scaffold
VSNU Open Access deal, 2020Co-Authors: K Torii, Jouke Dijkstra, Erhan Tenekecioglu, Yohei Sotomi, Yuki Katagiri, Taku Asano, Ply Chichareon, Rodrigo Modolo, Kuniaki Takahashi, Hans JonkerAbstract:textabstractAIMS: Scaffold design and plaque characteristics influence implantation outcomes and local flow dynamics in treated coronary segments. Our aim is to assess the impact of Strut embedment/protrusion of bioresorbable scaffold on local shear stress distribution in different atherosclerotic plaque types. METHODS AND RESULTS: Fifteen Absorb everolimus-eluting Bioresorbable Vascular Scaffolds were implanted in human epicardial coronary arteries. Optical coherence tomography (OCT) was performed post-scaffold implantation and Strut embedment/protrusion were analysed using a dedicated software. OCT data were fused with angiography to reconstruct 3D coronary anatomy. Blood flow simulation was performed and wall shear stress (WSS) was estimated in each scaffolded surface and the relationship between Strut embedment/protrusion and WSS was evaluated. There were 9083 Struts analysed. Ninety-seven percent of the Struts (n = 8840) were well-apposed and 243 (3%) were malapposed. At cross-section level (n = 1289), Strut embedment was significantly increased in fibroatheromatous plaques (76 ± 48 µm) and decreased in fibrocalcific plaques (35 ± 52 µm). Compatible with Strut embedment, WSS was significantly higher in lipid-rich fibroatheromatous plaques (1.50 ± 0.81 Pa), whereas significantly decreased in fibrocalcified plaques (1.05 ± 0.91 Pa). After categorization of WSS as low (<1.0 Pa) and normal/high WSS (≥1.0 Pa), the percent of low WSS in the plaque subgroups were 30.1%, 31.1%, 25.4%, and 36.2% for non-diseased vessel wall, fibrous plaque, fibroatheromatous plaque, and fibrocalcific plaque, respectively (P-overall < 0.001). CONCLUSION: The composition of the underlying plaque influences Strut embedment which seems to have effect on WSS. The Struts deeply embedded in lipid-rich fibroatheromas plaques resulted in higher WSS compared with the other plaque types.
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the impact of plaque type on Strut embedment protrusion and shear stress distribution in bioresorbable scaffold
European Journal of Echocardiography, 2019Co-Authors: Ryo Torii, Jouke Dijkstra, Erhan Tenekecioglu, Yohei Sotomi, Yuki Katagiri, Taku Asano, Ply Chichareon, Rodrigo Modolo, Kuniaki Takahashi, Hans JonkerAbstract:AIMS: Scaffold design and plaque characteristics influence implantation outcomes and local flow dynamics in treated coronary segments. Our aim is to assess the impact of Strut embedment/protrusion of bioresorbable scaffold on local shear stress distribution in different atherosclerotic plaque types. METHODS AND RESULTS: Fifteen Absorb everolimus-eluting Bioresorbable Vascular Scaffolds were implanted in human epicardial coronary arteries. Optical coherence tomography (OCT) was performed post-scaffold implantation and Strut embedment/protrusion were analysed using a dedicated software. OCT data were fused with angiography to reconstruct 3D coronary anatomy. Blood flow simulation was performed and wall shear stress (WSS) was estimated in each scaffolded surface and the relationship between Strut embedment/protrusion and WSS was evaluated. There were 9083 Struts analysed. Ninety-seven percent of the Struts (n = 8840) were well-apposed and 243 (3%) were malapposed. At cross-section level (n = 1289), Strut embedment was significantly increased in fibroatheromatous plaques (76 ± 48 µm) and decreased in fibrocalcific plaques (35 ± 52 µm). Compatible with Strut embedment, WSS was significantly higher in lipid-rich fibroatheromatous plaques (1.50 ± 0.81 Pa), whereas significantly decreased in fibrocalcified plaques (1.05 ± 0.91 Pa). After categorization of WSS as low (<1.0 Pa) and normal/high WSS (≥1.0 Pa), the percent of low WSS in the plaque subgroups were 30.1%, 31.1%, 25.4%, and 36.2% for non-diseased vessel wall, fibrous plaque, fibroatheromatous plaque, and fibrocalcific plaque, respectively (P-overall < 0.001). CONCLUSION: The composition of the underlying plaque influences Strut embedment which seems to have effect on WSS. The Struts deeply embedded in lipid-rich fibroatheromas plaques resulted in higher WSS compared with the other plaque types.
Konstantinos Dimopoulos - One of the best experts on this subject based on the ideXlab platform.
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an optical coherence tomography study of a biodegradable vs durable polymer coated limus eluting stent a leaders trial sub study
European Heart Journal, 2010Co-Authors: Peter Barlis, Giuseppe Ferrante, Willem J. Giessen, Patrick W.j.c. Serruys, Evelyn Regar, Robert-jan Van Geuns, Konstantinos Dimopoulos, Simon Wandel, Stephan Windecker, Pedro EerdmansAbstract:Aims Incomplete endothelialization has been found to be associated with late stent thrombosis, a rare but devastating phenomenon, more frequent after drug-eluting stent implantation. Optical coherence tomography (OCT) has 10 times greater resolution than intravascular ultrasound and thus appears to be a valuable modality for the assessment of stent Strut coverage. The LEADERS trial was a multi-centre, randomized comparison of a biolimus-eluting stent (BES) with biodegradable polymer with a sirolimus-eluting stent (SES) using a durable polymer. This study sought to evaluate tissue coverage and apposition of stents using OCT in a group of patients from the randomized LEADERS trial. Methods and results Fifty-six consecutive patients underwent OCT during angiographic follow-up at 9 months. OCT images were acquired using a non-occlusive technique at a pullback speed of 3 mm/s. Data were analysed using a Bayesian hierarchical random-effects model, which accounted for the correlation of lesion characteristics within patients and implicitly assigned analytical weights to each lesion depending on the number of Struts observed per lesion. Primary outcome was the difference in percentage of uncovered Struts between BESs and SESs. Twenty patients were included in the analysis in the BES group (29 lesions with 4592 Struts) and 26 patients in the SES group (35 lesions with 6476 Struts). A total of 83 Struts were uncovered in the BES group and 407 out of 6476 Struts were uncovered in the SES group [weighted difference −1.4%, 95% confidence interval (CI) −3.7 to 0.0, P = 0.04]. Results were similar after adjustment for pre-procedure lesion length, reference vessel diameter, number of implanted study stents, and presence of stent overlap. There were three lesions in the BES group and 15 lesions in the SES group that had ≥5% of all Struts uncovered (difference −33.1%, 95% CI −61.7 to −10.3, P < 0.01). Conclusion Strut coverage at an average follow-up of 9 months appears to be more complete in patients allocated to BESs when compared with SESs. The impact of this difference on clinical outcome and, in particular, on the risk of late stent thrombosis is yet to be determined.
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the influence of Strut thickness and cell design on immediate apposition of drug eluting stents assessed by optical coherence tomography
International Journal of Cardiology, 2009Co-Authors: Jun Tanigawa, Konstantinos Dimopoulos, Peter Barlis, Miles Dalby, Philip Moore, Carlo Di MarioAbstract:Abstract Background Stent Strut malapposition correlates with poor intimal coverage and this may increase the risk of late stent thrombosis. At present, there is limited data on whether stent Strut thickness and stent design impact on acute apposition. We aimed to investigate the influence of stent Strut thickness and design on acute stent Strut apposition (SSA) immediately following drug-eluting stent (DES) implantation using optical coherence tomography (OCT), a technique with higher resolution and fewer artefacts than intravascular ultrasound. Methods Thirty-six DES in 23 patients (25 lesions) were studied by OCT. SSA was defined as embedded when a Strut was buried in the intima for more than half its thickness, protruding when apposed to the intima but not embedded and malapposed when there was no intimal contact. Results Cypher Select stents were implanted in 52%, Taxus Liberte in 32%, Costar in 12% and Endeavour in 4%. A total of 6402 Struts were evaluated. Despite stent optimisation using balloons with a final balloon/artery ratio of 1.26±0.19 at a maximum inflation pressure of 17.5±3.0 atm, only 57.1±20.7% of Struts were embedded, whereas 33.8±18.4% were protruding and 9.1±7.4% were malapposed. Stent type was a strong predictor of malapposition on logistic multilevel analysis (OR 3.95, 95%CI: 1.27–12.23, p =0.017). At 12 months follow-up, there were no adverse clinical events. Conclusion Despite angiographic optimisation with high pressures and adequately sized balloons, malapposed stent Struts are frequently found in complex coronary lesions and more often following the implantation of Cypher Select stents which have a thicker stent Strut and closed cell design. With no adverse clinical events at 12 months follow-up, this likely represents a benign phenomenon at least as long as combined anti-platelet therapy is maintained.
