摘要
通过非线性有限元方法,建立了球囊扩张式冠脉支架自由扩张和狭窄血管体内扩张的数值计算模型。针对两种不同联接筋结构的冠脉支架,分析了S型和N型支架的自由扩张性能和介入狭窄血管后的体内扩张性能,研究了支架结构对血管组织机械损伤的影响机理。数值模拟结果表明,在自由扩张阶段,S型和N型支架变形均匀,两种支架的径向回弹率和轴向短缩率趋于一致,并且具有良好的扩张均匀性与一致性,有利于支架扩张狭窄血管和在血管内的精确定位。在体内扩张阶段,由于狭窄血管的约束作用,S型和N型支架的径向回弹率均高于自由扩张阶段,轴向短缩率均低于自由扩张阶段;但是S型支架介入狭窄血管后的径向回弹率和轴向短缩率略高于N型支架,引起了更低的血管应力水平和应力梯度,减少了血管组织的机械损伤,降低了支架介入术后的血管内再狭窄率。综上,提出的计算模型对于冠脉支架的生物力学性能评估、结构优化设计与介入术后的血管损伤评价提供了重要的理论依据。
The numerical model was presented to simulate the free expansion and in-vivo expansion in the stenosed vascular by nonlinear finite element method.Both free expansion and in-vivo performances are analyzed respectively for the S-stent and N-stent with different geometrical link from each other.Effects of different stent designs on the vascular injure are investigated.The numerical result indicates that the S-stent and N-stent are deployed homogeneously in addition that the radical recoil rate and the foreshortening rate of the S-stent are approximate to the counterpart of the N-stent in case of the free expansion.The S-stent and N-stent are provided with good expansion homogeneity,which contributes to expand the stenosed vascular and accurately position the stent.In case of the in-vivo expansion,the radical recoil rate of S-stent and N-stent is higher than that in case of the free expansion while the foreshortening rate is exactly opposite as a result of the interaction of the stenosed vascular.However,the radial recoil and foreshortening for the S-stent are higher than the counterpart for the N-stent.It results in less wall stress level and stress gradient on the stenosed vessel,contributing to the less vascular restenosis resulting from the vascular injure for the S-stent.Therefore this analysis model provides important theory guide to the biomechanical performance evaluation,the optimization design of stents and the vascular injure estimation by stent intervention.
出处
《功能材料》
EI
CAS
CSCD
北大核心
2016年第3期56-63,共8页
Journal of Functional Materials
基金
国家自然科学基金资助项目(81160186)
黑龙江省自然科学基金资助项目(E2015026)
关键词
冠脉支架
扩张变形
非线性有限元
血管损伤
再狭窄
coronary stent
expansion deformation
nonlinear finite element
vascular injure
restenosis
