中国机械工程

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高径向支撑性可生物降解聚合物血管支架结构设计与力学性能分析

魏云波;赵丹阳;王敏杰;李红霞   

  1. 大连理工大学机械工程学院,大连,116024
  • 出版日期:2020-05-10 发布日期:2020-06-17
  • 基金资助:
    国家自然科学基金资助项目(51675079,11502044);
    中央高校基本科研业务费专项资金资助项目(DUT17RC(3)104)

Design and Mechanics Analysis of Biodegradable Polymer Vascular Stents with High Radial Supporting Property

WEI Yunbo;ZHAO  Danyang;WANG  Minjie;LI  Hongxia   

  1. School of Mechanical Engineering,Dalian University of Technology,Dalian,Liaoning,116024
  • Online:2020-05-10 Published:2020-06-17

摘要: 在研究血管支架支撑单元夹角与其径向支撑强度关系的基础上,提出采用不等高支撑环以利于增大扩张后支撑单元夹角进而提高支架径向支撑强度的设计方法,根据该方法设计了三种可降解聚合物血管支架结构。采用有限元方法对比分析了该三种支架和雅培生物可降解支架(BVS)的径向支撑强度、径向回缩率、轴向短缩率与弯曲刚度,研究了支架结构对这些性能的影响规律。所设计的J型支架(JS)、开放式C型支架(OCS)和密闭式C型支架(CCS)的径向支撑强度相对BVS的径向支撑强度分别提高了14%、34%和42%,同时设计的三种支架的径向回缩率相对BVS的径向回缩率减小了约21%,且均未发生轴向短缩;采用开放式连接形式的JS、OCS的弯曲刚度与BVS的弯曲刚度相当,相比密闭式CCS减小了约73%。影响径向支撑强度和径向回缩率的主要因素是支撑环的结构形式,采用不等高支撑环可有效改善径向支撑强度和径向回缩率;影响轴向短缩率的主要因素是桥筋的结构形式和桥筋的连接位置,采用具有弯曲结构的桥筋且桥筋连接位置位于支撑单元直线段的中间处可避免支架发生轴向短缩;影响弯曲刚度的主要因素是桥筋与支撑环的连接形式,采用开放式连接的支架弯曲刚度更小。

关键词: 可生物降解聚合物, 血管支架, 径向支撑强度, 径向回缩, 轴向短缩, 弯曲刚度

Abstract: Based on the study of the relationship between strut angle of a stent and the radial supporting strength, a novel design method was proposed herein. Specifically, unequal-height supporting rings were used to increase the strut angle after expansion and furthermore improve the radial strength. Using this method, three kinds of biodegradable polymer vascular stents were designed. Radial strength, radial recoil, axial foreshortening and bending stiffness of the three stents were analyzed by finite element method and compared with Abbott bioresorbable vascular scaffolds(BVS). The influences of the structures on properties of the stents were studied. The radial strength of the designed JS(J-type stent), OCS(open C-type stent) and CCS(closed C-type stent) is as 14%, 34% and 42% higher than that of the BVS, respectively. The recoil of the designed stents is about 21% lower than that of the BVS. Meanwhile, all the designed stents have no axial shortening. The bending stiffness of the JS and OCS, which have open cells, is comparable to that of BVS and is about 73% lower than that of the CCS, which has closed cells. The radial supporting strength and radial recoil mainly depend on the structural form of the supporting rings. These two properties may be effectively improved by employing unequal-height supporting rings. The axial foreshortening is mainly determined by the structural form and the connection positions of the bridges. The axial shortening of the stents may be avoided by using bridges with curved structures and setting the connection positions in the middle of the straight section of the supporting elements. The bending stiffness is mainly affected by the connection form between the bridges and the supporting rings. The bending stiffness is lower if the stent has open cells.

Key words: biodegradable polymer, vascular stent, radial supporting strength, radial recoil, axial foreshortening, bending stiffness

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