The stent was a major breakthrough in the treatment of atherosclerotic vascular disease. The permanent vascular implant of a stent, however, changes the intra-stent blood flow hemodynamics. There is a growing consensu...The stent was a major breakthrough in the treatment of atherosclerotic vascular disease. The permanent vascular implant of a stent, however, changes the intra-stent blood flow hemodynamics. There is a growing consensus that the stent implant may change the artery wall shear stress distribution and hence lead to the restenosis process. Computational fluid dynamics (CFD) has been widely used to analyze hemodynamics in stented arteries. In this paper, two CFD models (the axisymmetric model and the 3-D stent model) were developed to investigate the effects of strut geometry and blood rheology on the intra-stent hemodynamics. The velocity profile, flow recirculation, and wall shear stress distribution of various stent strut geometries were studied. Results show strong correlations between the intra-stent hemodynamics and strut geometry. The intra-stent blood flow is very sensitive to the strut height and fillet size. A round strut with a large fillet size shows 36% and 34% reductions in key parameters evaluating the restenosis risk for the axisymmetric model and the 3-D stent model, respectively. This suggests that electrochemical polishing, a surface-improving process during stent manufacturing, strongly influences the hemodynamic behavior in stented arteries and should be controlled precisely in order to achieve the best clinical outcome. Rheological effects on the wall shear stress are minor in both axisymmetric and 3-D stent models for the vessel diameter of 4 mm, with Newtonian flow simulation tending to give more conservative estimates ofrestenosis risk. Therefore, it is reasonable to simulate the blood flow as a Newtonian flow in stented arteries using the simpler axisymmetric model. These findings will provide great insights for stent design optimization for potential restenosis improvement.展开更多
Background Coronary artery stenting is commonly used for the treatment of coronary atherosclerosis,but it causes serious clinical complications,such as the in-stent restenosis(ISR).The main reason leading to ISR is th...Background Coronary artery stenting is commonly used for the treatment of coronary atherosclerosis,but it causes serious clinical complications,such as the in-stent restenosis(ISR).The main reason leading to ISR is the neointimal hyperplasia(NH),which is related to the stresses of plaque and artery,and to the altered local hemodynamic environment due to the presence of stents.Different stent structures indeed have various impacts on the stresses of plaque and artery,and the local hemodynamic environment,such as the wall shear stress(WSS),average WSS(AWSS),and WSS gradient(WSSG).Thus,it is important to evaluate the performance of stents with different structures by the mechanical factors after coronary stenting.Methods Six stents implanted into a stenotic curved coronary artery were treated separately,and they included three typical commercial stents(Palmaz-Schatz,Xience,and Cypher)and three author-developed stents,which were constructed by reducing the numbers of link(C-Rlink)and crown(C-Rcrown),and aligning the strut(C-Astrut)of the commercial Cypher Solid mechanical analyses of the balloon-stent-plaque-artery system in Abaqus were first performed to assess the performance of different stent structures and provide the deformed boundary of lumen for the subsequent hemodynamic analysis.With the deformed boundary,then hemodynamic analyses in Ansys were conducted to quanti-fy the hemodynamic parameters induced by different stent structures.Combining the solid mechanical and hemodynamic analyses,the performance of the six stents was evaluated.Results The results show that among the three commercial stents,the Palmaz-Schatz stent has the least stent dogboning and recoiling,which corresponds to the greatest maximum plastic strain as well as the largest diameter.However,it induces the greatest maximum stress of plaque,intima,and media.From the viewpoint of hemodynamics,the Palmaz-Schatz stent also performs better and it has smaller areas of adverse low WSS(<0.5 Pa),high WSS(>15 Pa),low AWSS(<0.5 Pa),and high WSSG(>5 000 Pa/m).Compared to the commercial Cypher stent,the author-developed Cypher-based C-Rcrown and C-Astrut stents have smaller recoiling,greater maximum plastic stain and larger diameter,which indicates the improved mechanical performance of the Cypher stent.Moreover,both C-Rcrown and C-Astrut have smaller areas of adverse low WSS,high WSS,and low AWSS,but only C-Rcrown has smaller area of adverse high WSSG.Nevertheless,the C-Rlink stent is inferior to the commercial Cypher stent.In both senses of the solid mechanical and local hemodynamic analyses,the C-Rcrown stent is superior to the commercial Cypher stent and other Cypher-based stents.Conclusions In this study,solid mechanical and hemodynamic analyses were carried out to study the effects of six stents with different structures on their performances after stenting.It was found that the Palmaz-Schatz stent performed better than other two commercial stents,and the performance of the Cypher stent could be improved by reducing the number of crowns of its strut.The present study comparatively evaluates the performance of different stents inside a curved artery,and could be used as a guide to select a suitable commercial stent for clinical application,and provide a way to improve the performance of the existing commercial stents.展开更多
AIM: To evaluate the premise, that biodegradable polymer drug eluting stents(BD-DES) could improve clinical outcomes compared to second generation permanent polymer drug eluting stents(PP-DES), we pooled the data from...AIM: To evaluate the premise, that biodegradable polymer drug eluting stents(BD-DES) could improve clinical outcomes compared to second generation permanent polymer drug eluting stents(PP-DES), we pooled the data from all the available randomized control trials(RCT) comparing the clinical performance of both these stents.METHODS: A systematic literature search of Pub Med, Cochrane, Google scholar databases, EMBASE, MEDLINE and SCOPUS was performed during time period of January 2001 to April 2015 for RCT and comparing safety and efficacy of BD-DES vs second generation PP-DES. The primary outcomes of interest were definite stent thrombosis, target lesion revascularization, myocardial infarction, cardiac deaths and total deaths during the study period. RESULTS: A total of 11 RCT's with a total of 12644 patients were included in the meta-analysis, with 6598 patients in BD-DES vs 6046 patients in second generation PP-DES. The mean follow up period was 16 mo. Pooled analysis showed non-inferiority of BD-DES, comparing events of stent thrombosis(OR = 1.42, 95%CI: 0.79-2.52, P = 0.24), target lesion revascularization(OR = 0.99, 95%CI: 0.84-1.17, P = 0.92), myocardial infarction(OR = 1.06, 95%CI: 0.86-1.29, P = 0.92), cardiac deaths(OR = 1.07, 95%CI 0.82-1.41, P = 0.94) and total deaths(OR = 0.96, 95%CI: 0.80-1.17, P = 0.71).CONCLUSION: BD-DES, when compared to second generation PP-DES, showed no significant advantage and the outcomes were comparable between both the groups.展开更多
Background: The biodegradable polymer-coated sirolimus-eluting coro-nary stent (SES) system for the treatment of coronary artery disease (CAD) has been implanted in a real-world patient population. Aim: The present st...Background: The biodegradable polymer-coated sirolimus-eluting coro-nary stent (SES) system for the treatment of coronary artery disease (CAD) has been implanted in a real-world patient population. Aim: The present study was designed to evaluate the safety and performance of MetaforTM sirolimus- eluting coronary stent (SES) system in consecutive patients with CAD in a real-world patient population. Methods: All the consecutive 251 patients who underwent percutaneous coronary interventions with the use of Metafor sirolimus-eluting stents were included in this study. Patients were clinically/tele- phonically followed-up at one-year from August 2015 to August 2016. We observed and analyzed major adverse cardiac event (MACE) defined as the aggregate of cardiac death, myocardial infarction (MI), and any target lesion revascularization (TLR) at one-year. Also, stent thrombosis (ST) was observed at one-year patients follow-up. Results: We collected and analyzed the data for 251 patients. Out of 251 participants, 191 (76.1%) were males, 95 (37.8%) patients had diabetes, 117 (46.6%) had ST-segment-elevation myocardial infarction (STEMI), and 134 (53.4%) had hypertension. Mean patient age was 56.35 ± 11.23 years. A total of 295 lesions were treated, out of which 13.6% of the lesions were the long lesion of ≥40 mm. At one-year, MACE occurred in 4 (1.6%) of 251 patients, consisting of 2 (0.8%) cardiac deaths, 2 (0.8%) MI, and 0 (0%) TLR. Stent thrombosis was reported in one patient (0.4%). Conclusions: This retrospective data demonstrated excellent safety and performance of Metafor SES in a “real-world” consecutive CAD patient, indicating low rates of MACE and ST at one-year follow-up.展开更多
在分析个性化血管支架特点的基础上,建立了面向病人个性化需求的医用血管支架快速设计系统的功能体系结构和工作流程,并对实现系统功能所涉及的血管病变部位数据获取、血管支架快速设计方法等关键技术进行了研究.在Pro/E W ildfire环境...在分析个性化血管支架特点的基础上,建立了面向病人个性化需求的医用血管支架快速设计系统的功能体系结构和工作流程,并对实现系统功能所涉及的血管病变部位数据获取、血管支架快速设计方法等关键技术进行了研究.在Pro/E W ildfire环境下,利用其二次开发工具Pro/Toolkit,融合血管病变部位数据获取技术,建立了基于支架三维标准库和实例推理技术的支架选型、支架快速参数化设计的支架快速设计集成系统.该系统实用性强、效率高,能大幅缩短支架产品开发周期.展开更多
文摘The stent was a major breakthrough in the treatment of atherosclerotic vascular disease. The permanent vascular implant of a stent, however, changes the intra-stent blood flow hemodynamics. There is a growing consensus that the stent implant may change the artery wall shear stress distribution and hence lead to the restenosis process. Computational fluid dynamics (CFD) has been widely used to analyze hemodynamics in stented arteries. In this paper, two CFD models (the axisymmetric model and the 3-D stent model) were developed to investigate the effects of strut geometry and blood rheology on the intra-stent hemodynamics. The velocity profile, flow recirculation, and wall shear stress distribution of various stent strut geometries were studied. Results show strong correlations between the intra-stent hemodynamics and strut geometry. The intra-stent blood flow is very sensitive to the strut height and fillet size. A round strut with a large fillet size shows 36% and 34% reductions in key parameters evaluating the restenosis risk for the axisymmetric model and the 3-D stent model, respectively. This suggests that electrochemical polishing, a surface-improving process during stent manufacturing, strongly influences the hemodynamic behavior in stented arteries and should be controlled precisely in order to achieve the best clinical outcome. Rheological effects on the wall shear stress are minor in both axisymmetric and 3-D stent models for the vessel diameter of 4 mm, with Newtonian flow simulation tending to give more conservative estimates ofrestenosis risk. Therefore, it is reasonable to simulate the blood flow as a Newtonian flow in stented arteries using the simpler axisymmetric model. These findings will provide great insights for stent design optimization for potential restenosis improvement.
基金supported by the Natural Science Foundation of China ( NSFC) ( 31300780,11272091, 11422222,31470043)supported by the National 973 Basic Research Program of China ( 2013CB733800)China scholarship Council ( 201706090121) ,and ARC ( FT140101152)
文摘Background Coronary artery stenting is commonly used for the treatment of coronary atherosclerosis,but it causes serious clinical complications,such as the in-stent restenosis(ISR).The main reason leading to ISR is the neointimal hyperplasia(NH),which is related to the stresses of plaque and artery,and to the altered local hemodynamic environment due to the presence of stents.Different stent structures indeed have various impacts on the stresses of plaque and artery,and the local hemodynamic environment,such as the wall shear stress(WSS),average WSS(AWSS),and WSS gradient(WSSG).Thus,it is important to evaluate the performance of stents with different structures by the mechanical factors after coronary stenting.Methods Six stents implanted into a stenotic curved coronary artery were treated separately,and they included three typical commercial stents(Palmaz-Schatz,Xience,and Cypher)and three author-developed stents,which were constructed by reducing the numbers of link(C-Rlink)and crown(C-Rcrown),and aligning the strut(C-Astrut)of the commercial Cypher Solid mechanical analyses of the balloon-stent-plaque-artery system in Abaqus were first performed to assess the performance of different stent structures and provide the deformed boundary of lumen for the subsequent hemodynamic analysis.With the deformed boundary,then hemodynamic analyses in Ansys were conducted to quanti-fy the hemodynamic parameters induced by different stent structures.Combining the solid mechanical and hemodynamic analyses,the performance of the six stents was evaluated.Results The results show that among the three commercial stents,the Palmaz-Schatz stent has the least stent dogboning and recoiling,which corresponds to the greatest maximum plastic strain as well as the largest diameter.However,it induces the greatest maximum stress of plaque,intima,and media.From the viewpoint of hemodynamics,the Palmaz-Schatz stent also performs better and it has smaller areas of adverse low WSS(<0.5 Pa),high WSS(>15 Pa),low AWSS(<0.5 Pa),and high WSSG(>5 000 Pa/m).Compared to the commercial Cypher stent,the author-developed Cypher-based C-Rcrown and C-Astrut stents have smaller recoiling,greater maximum plastic stain and larger diameter,which indicates the improved mechanical performance of the Cypher stent.Moreover,both C-Rcrown and C-Astrut have smaller areas of adverse low WSS,high WSS,and low AWSS,but only C-Rcrown has smaller area of adverse high WSSG.Nevertheless,the C-Rlink stent is inferior to the commercial Cypher stent.In both senses of the solid mechanical and local hemodynamic analyses,the C-Rcrown stent is superior to the commercial Cypher stent and other Cypher-based stents.Conclusions In this study,solid mechanical and hemodynamic analyses were carried out to study the effects of six stents with different structures on their performances after stenting.It was found that the Palmaz-Schatz stent performed better than other two commercial stents,and the performance of the Cypher stent could be improved by reducing the number of crowns of its strut.The present study comparatively evaluates the performance of different stents inside a curved artery,and could be used as a guide to select a suitable commercial stent for clinical application,and provide a way to improve the performance of the existing commercial stents.
文摘AIM: To evaluate the premise, that biodegradable polymer drug eluting stents(BD-DES) could improve clinical outcomes compared to second generation permanent polymer drug eluting stents(PP-DES), we pooled the data from all the available randomized control trials(RCT) comparing the clinical performance of both these stents.METHODS: A systematic literature search of Pub Med, Cochrane, Google scholar databases, EMBASE, MEDLINE and SCOPUS was performed during time period of January 2001 to April 2015 for RCT and comparing safety and efficacy of BD-DES vs second generation PP-DES. The primary outcomes of interest were definite stent thrombosis, target lesion revascularization, myocardial infarction, cardiac deaths and total deaths during the study period. RESULTS: A total of 11 RCT's with a total of 12644 patients were included in the meta-analysis, with 6598 patients in BD-DES vs 6046 patients in second generation PP-DES. The mean follow up period was 16 mo. Pooled analysis showed non-inferiority of BD-DES, comparing events of stent thrombosis(OR = 1.42, 95%CI: 0.79-2.52, P = 0.24), target lesion revascularization(OR = 0.99, 95%CI: 0.84-1.17, P = 0.92), myocardial infarction(OR = 1.06, 95%CI: 0.86-1.29, P = 0.92), cardiac deaths(OR = 1.07, 95%CI 0.82-1.41, P = 0.94) and total deaths(OR = 0.96, 95%CI: 0.80-1.17, P = 0.71).CONCLUSION: BD-DES, when compared to second generation PP-DES, showed no significant advantage and the outcomes were comparable between both the groups.
文摘Background: The biodegradable polymer-coated sirolimus-eluting coro-nary stent (SES) system for the treatment of coronary artery disease (CAD) has been implanted in a real-world patient population. Aim: The present study was designed to evaluate the safety and performance of MetaforTM sirolimus- eluting coronary stent (SES) system in consecutive patients with CAD in a real-world patient population. Methods: All the consecutive 251 patients who underwent percutaneous coronary interventions with the use of Metafor sirolimus-eluting stents were included in this study. Patients were clinically/tele- phonically followed-up at one-year from August 2015 to August 2016. We observed and analyzed major adverse cardiac event (MACE) defined as the aggregate of cardiac death, myocardial infarction (MI), and any target lesion revascularization (TLR) at one-year. Also, stent thrombosis (ST) was observed at one-year patients follow-up. Results: We collected and analyzed the data for 251 patients. Out of 251 participants, 191 (76.1%) were males, 95 (37.8%) patients had diabetes, 117 (46.6%) had ST-segment-elevation myocardial infarction (STEMI), and 134 (53.4%) had hypertension. Mean patient age was 56.35 ± 11.23 years. A total of 295 lesions were treated, out of which 13.6% of the lesions were the long lesion of ≥40 mm. At one-year, MACE occurred in 4 (1.6%) of 251 patients, consisting of 2 (0.8%) cardiac deaths, 2 (0.8%) MI, and 0 (0%) TLR. Stent thrombosis was reported in one patient (0.4%). Conclusions: This retrospective data demonstrated excellent safety and performance of Metafor SES in a “real-world” consecutive CAD patient, indicating low rates of MACE and ST at one-year follow-up.
文摘在分析个性化血管支架特点的基础上,建立了面向病人个性化需求的医用血管支架快速设计系统的功能体系结构和工作流程,并对实现系统功能所涉及的血管病变部位数据获取、血管支架快速设计方法等关键技术进行了研究.在Pro/E W ildfire环境下,利用其二次开发工具Pro/Toolkit,融合血管病变部位数据获取技术,建立了基于支架三维标准库和实例推理技术的支架选型、支架快速参数化设计的支架快速设计集成系统.该系统实用性强、效率高,能大幅缩短支架产品开发周期.