利用随机有限元法模拟聚合物血管支架降解过程  

Simulation of Degradation Process of Polymer Vascular Stent Using the Stochastic Finite Element Method

作　　者：牛文娟 周鹏 王强 NIU Wenjuan;ZHOU Peng;WANG Qiang(Shaanxi Metallurgical Engineering and Technology Research Center,School of Metallurgical Engineering,Xi’an University of Architecture and Technology,Xi’an 710055,China)

机构地区：[1]西安建筑科技大学冶金工程学院,陕西省冶金工程技术研究中心,西安710055

出　　处：《医用生物力学》2024年第5期846-852,共7页Journal of Medical Biomechanics

摘　　要：目的针对生物可降解血管支架植入后产生的晚期支柱血栓问题,建立随机有限元模型,从分子量和应力角度对聚合物血管支架降解过程进行生物力学分析。方法建立以聚乳酸(poly lactic acid,PLA)高分子材料为例的可降解血管支架降解过程的数学模型,利用COMSOL软件将数学模型导入并完成有限元模型的构建;对有限元模型进行随机化处理,分析不同随机参数和标准差对分子量的影响以及降解过程中的应力分布。结果可降解聚合物血管支架在人体的降解过程中,随机变量M_(n0)和8%标准差对分子量分布的影响最为显著;参数随机化会导致聚合物血管支架降解过程中断裂强度的分布范围更广,最小值更低。结论聚合物血管支架材料中分子量分布的不均匀性导致支架不同位置上的力学性能差异,进而引起材料内部的应力集中现象,最终导致支架在降解过程中发生非均匀破碎,成为后期支架血栓形成的决定性因素。研究结果为下一代可降解血管支架设计提供理论指导。Objective To address the problem of late strut thrombosis generated after the implantation of biodegradable vascular stents,a stochastic finite element model was established to perform biomechanical analysis on the degradation process of polymer vascular stent from the perspectives of molecular weight and stress.Methods A mathematical model of the degradation process of biodegradable vascular scaffolds using poly lactic acid(PLA)was established and the mathematical model was imported,and a finite element model was constructed using COMSOL software.The model was stochastically used to analyze the effects on molecular weight and stress distribution in the degradation process under different stochastic parameters and standard deviations.Results During the degradation process of degradable polymer vascular scaffolds in human body,the random variables M_(n0)and 8%standard deviation had the most significant effects on the distribution of molecular weights;randomization of the parameters led to a wider distribution range of the fracture strength during the degradation process of polymer vascular scaffolds,and the minimum value of fracture strength was lower.Conclusions The inhomogeneity of molecular weight distribution in polymer vascular stent materials leads to differences in mechanical properties at different locations of the stent,which in turn causes stress concentration within the material,ultimately leading to non-uniform fragmentation of the stent during degradation,which becomes a determining factor for stent thrombosis in later stages.This study provides theoretical guidance for designing next-generation biodegradable vascular stents.

关 键 词：可降解聚合物血管支架 降解模型 非均匀破碎 分子量 应力 

分 类 号：R318.01[医药卫生—生物医学工程]