冠脉支架设计的材料适应性研究  

Material Adaptability of Coronary Stent Design

作　　者：叶锟 张弢[1,2] YE Kun;ZHANG Tao(College of Engineering and Applied Sciences,Nanjing University,Nanjing 210023,China;Wuxi Xishan NJU Institute of Applied Biotechnology,Wuxi 214105,Jiangsu,China)

机构地区：[1]南京大学现代工程与应用科学学院,南京210023 [2]无锡市南京大学锡山应用生物技术研究所,江苏无锡214105

出　　处：《医用生物力学》2023年第6期1211-1218,共8页Journal of Medical Biomechanics

基　　金：国家重点研发计划项目(2022YFA1203002)。

摘　　要：目的 基于一种确定的冠脉支架设计,分析不同材料的适应性,建立支架设计-材料选择的评价方法。方法 针对可能应用的5种支架材料,利用有限元数值模拟方法分析支架在血管中的扩张性能,考察支架设计和材料的安全性及可用性。针对不可降解材料重点考察支架在长期植入后的耐疲劳性能;对可降解材料分析其降解过程中的支撑力变化,明确支架所能提供的支撑力的规律。结果 针对确定的冠脉支架设计,模拟显示316L不锈钢和L605钴铬合金支架的径向回弹率分别是26%和19%,轴向缩短率分别为0.22%和0.28%,最大等效应力分别为551.2、829.1 MPa,疲劳动态安全系数分别为1.36和1.67,针对可降解材料AZ31镁合金、铁和左旋聚乳酸(PLLA),基于该设计的支架的模拟破坏时间分别为30 h和180、270 d。结论 基于本文的支架设计,L605钴铬合金具有最佳的扩张性能和耐疲劳性能,可以满足临床需求。相较于AZ31的快速降解破坏,铁支架和PLLA支架的力学性能接近,但仍需结构优化后才能满足临床需求。有限元数值模拟,尤其是扩张性能和耐疲劳性能分析,可以有效模拟支架力学行为,并为支架制造材料选择和设计优化提供依据。Objective To analyze the adaptability of different materials based on a defined coronary stent design,and to establish an evaluation method for stent design-material selection.Methods Using finite element numerical simulation method,the expansion performance of the stent in blood vessel was analyzed,and the safety and usability of the stent design and materials were investigated for five potential applicable materials.For non-degradable materials,the focus was on the fatigue resistance performance after long-term implantation;while for degradable materials,the changes of support force during degradation were analyzed to clarify the rules of support force provided by the stent.Results For the specific coronary stent design,the simulation showed that for 316L stainless steel and L605 cobalt-chromium alloy stents,the radial recoils were 26% and 19%,the axial foreshortening were 0.22% and 0.28%,the maximum equivalent stresses were 551.2 MPa and 829.1 MPa,and the fatigue dynamic safety factors were 1.36 and 1.67,respectively.For degradable materials AZ31 magnesium alloy,iron and poly(L-lactic acid)(PLLA),the simulated damage time of the stents based on this design was 30 h and 180 d,270 d respectively.Conclusions Based on stent design in this study,the L605 cobalt-chromium alloy exhibited the best expansion performance and fatigue resistance to match the clinical requirements.Compared with the rapid degradation damage of AZ31,the mechanical properties of iron stent and PLLA stent were close but still needed structural optimization.The finite element numerical simulation,especially analysis on expansion performance and fatigue resistance,can effectively simulate mechanical behavior of the stent and provide references for the selections of stent materials and the design optimization.

关 键 词：冠脉支架 可降解材料 不可降解材料 耐疲劳 支架设计 

分 类 号：R318.01[医药卫生—生物医学工程]