新型可回收血管支架的设计与有限元分析

Design and Finite Element Analysis of a Novel Retrievable Vascular Stent

目的针对药物洗脱支架植入后引起的早期再狭窄问题,对镍钛合金血管支架进行结构上的可回收设计和生物力学分析。方法建立可回收血管支架及其回收系统的几何模型,其中支架回收部为圆台形网状结构,由4个对称分布的回收筋组成;分析支架在压握过程中的最大主应变分布、压握及自膨胀均匀性等,并对支架的回收过程进行仿真实验。结果当支架被压握至最小尺寸时,其最大应变为3.7%,不均匀性指数为0.62%;当支架自膨胀结束时,其不均匀性指数为1.31%;当1/2支架被回收进外鞘管时,最大应变为1.52%;而支架在回收过程中并未发生断裂或"卡顿"情况。结论支架应变在其安全范围之内,且支架的压握及自膨胀过程较均匀,能够被安全、顺利地回收进外鞘管中。研究结果可以为可回收血管支架的结构设计、生物力学分析和临床应用提供重要参考依据。

Objective In order to avoid early restenosis after drug-eluting stent( DES) implantation, the retrievable structure of the Ni Ti alloy stent and its biomechanical analysis were studied. Methods The geometric models of the retrievable vascular stent and the retrieval system were established. The retrieval part of the stent consisted of four symmetrically distributed tendons,which were designed as circular meshes. The distribution of the maximum strain during stent compression and its uniformity during compression and self-expansion were analyzed,and the simulation experiments of the retrieval process were also performed. Results The maximum strain of the stent was 3. 7% and the index of non-uniformity( INU) was 0. 62% when the stent was compressed to the minimum size. While the IBU was 1. 31% after the self-expansion process completed. The maximum strain was 1. 52% when half of the stent was retrieved into the outer sheath. Conclusions The stent could be safely and successfully retrieved into the outer sheath as the strain was within the bearable range of the material and the compression and self-expansion process was relatively uniform. The research findings provide important references for structural design,biomechanical analysis and potential clinical applications of the novel retrievable vascular stent.