可回收外周血管支架设计与生物力学研究

为解决传统支架长期滞留体内诱发支架内再狭窄的问题，设计一种新型可回收外周血管支架，并对其安全性与有效性进行力学分析。首先建立支架和外周斑块血管有限元模型，对支架进行压握、自由扩张过程的有限元分析，比对分析结果与径向支撑力测试结果，发现误差小于10%，验证了支架有限元模型有效性；在此基础上，再对支架植入及回收过程进行仿真模拟，分析与血管耦合条件下支架与血管生物力学性能。压握过程中支架最大应变为5.919%，回收过程中支架所受等效应力最大值为691MPa，均小于支架材料镍钛合金最大弹性应变及屈服应力。自膨胀扩张过程中血管所受最大等效应力值为0.592 6MPa，支架回收过程中血管所受等效应力最大值为0.536 6MPa，均小于血管损伤应力。试验结果表明，新型可回收外周血管支架理论上是可回收的，并且在植入以及回收过程中，其力学性能安全可靠。

Design and Biomechanical Research of Retrievable Peripheral Vascular Stents

In order to solve the problem of restenosis induced by long-term retention of traditional stent， a new type of recyclable peripheral vascular stent is designed， and its safety and effectiveness are analyzed. The finite element model of the stent and peripheral stenotic vessel is established. Finite element analysis is carried out to stimulate the stent’s crimping and self-expansion. The results proves that the error between the radial support force test outcome and the finite element analysis result are less than 10%， which verifies the validity of the finite element model. On this basis， the simulation of the stent implantation and retrieval process is carried out， and the biomechanical properties of the stent and blood vessel under the condition of coupling between blood vessels and stent are analyzed. The maximum strain of the stent during the crimping process was 5.919%. The maximum equivalent stress of the stent during the retrieval process was 691 MPa， which was less than the maximum elastic strain and yield stress of the stent material. The maximum equivalent stress value of the blood vessel in the Self-expansion process was 0.592 6MPa， and the maximum equivalent stress of the blood vessel during the stent retrieval process was 0.536 6MPa which was smaller than the damaged stress of the blood vessel. The preliminary experiments demonstrates that the novel retrievable peripheral vascular stent is theoretically retrievable， and the mechanical properties during implantation and retrieval process are safe and reliable.