波峰数目对Z型覆膜支架生物力学性能影响  

Effects of strut numbers on biomechanical properties of Z-shaped stent-grafts

作　　者：于凯[1] 谷雪莲[1] 胡方遒[1] 李中华 宋成利[1] 

机构地区：[1]上海理工大学现代微创医疗器械及技术教育部工程研究中心,上海200093 [2]上海微创医疗器械(集团)有限公司,上海201203

出　　处：《医用生物力学》2017年第2期115-121,共7页Journal of Medical Biomechanics

基　　金：国家自然科学基金项目(51175345)

摘　　要：目的分析Z型覆膜支架波峰数目对覆膜支架生物力学性能,尤其对径向支撑性能及柔顺性影响,为Z型覆膜支架设计以及临床选择提供理论支持。方法通过有限元方法,建立4种不同波峰数目(5、8、10、12)的Z型覆膜支架有限元模型,分别施加径向位移载荷和绕z轴40°转动变量以完成压握和弯折的模拟,并提取支架应力、径向支撑力、覆膜应变、横截面变形程度及弯矩作为评价参数。结果相比波峰数目较多的覆膜支架,压握过程中5波峰覆膜支架具有最大的径向力,提供良好的径向支性能;5波峰覆膜支架在弯折模拟中产生了68 N·mm的最小力矩及67.5%的最小弯折横截面变形程度,并且在弯曲过程中覆膜的拉伸应变较小。结论 Z型覆膜支架波峰数目对覆膜支架生物力学性能的影响显著。波峰数目相对较少的Z型覆膜支架在径向支撑性能及弯曲力矩、横截面形变程度等柔顺性评价方面表现出优势,有利于覆膜支架在血管内的固定贴合,对减少血栓和内漏等并发症具有积极意义。研究结果可以指导Z型覆膜支架优化设计及手术最优选择。Objective To analyze the influence from strut numbers on biomechanical properties of Z-shaped stent- grafts, especially on their radial support performance and flexibility, so as to provide theoretical support for the design and clinical selection of Z-shaped stent-grafts. Methods Z-shaped stent-grafts with 5, 8, 10, 12 struts were established by finite element method to simulate the process of compression and bending behavior. Radial displacements were applied on surface of the stent-graft and opposite rotations were applied around the z-axis, until a bending angle of 40~ was reached. Then parameters such as stent stress, radial support force, strains in graft, cross-section deflection, bending torque were extracted to evaluate the performance of different stent- grafts. Results Compared with stent-grafts with more strut numbers, 5-strut stent-graft showed a better radial support performance with the maximum radial force during compression, and it also generated the smallest 68 N · mm torque and 67.5% cross-section deflection. The tensile strain in graft of 5-strut stent-graft during the process of bending was relatively smaller. Conclusions The strut number of Z-shaped stent-grafts has a signifi- cant influence on biomechanical properties of the stent-grafts. Especially the Z-shaped stent-graft with relatively fewer strut numbers shows an advantage in evaluating radial support performance and flexibility such as the ben- ding torque and the cross-section deflection, and is more suitable to be anchored and fit to the tortuous blood ves- sel, which will play a positive role in decreasing the complication such as endoleaks and thrombosis. The re- search findings can guide structure design of Z-shaped stent-grafts and optimal selection for surgery.

关 键 词：Z型覆膜支架 波峰数目 有限元分析 生物力学 

分 类 号：R318.01[医药卫生—生物医学工程]