不同材料冠状动脉支架膨胀行为分析

冠状动脉支架作为经皮穿刺冠状动脉成形术中保持病变血管畅通的核心器件,其在手术过程中受球囊作用的扩张特性以及球囊撤出后的反弹行为对支架植入术的成功有着重要的影响.利用有限元的方法系统,建立专有支架单独膨胀和血管支架膨胀模型,分析了316L不锈钢和L605钴铬合金两种材料支架筋尺寸和支架扩张尺度的变化及血管对其膨胀行为的影响.结果显示,支架所选材料是决定支架膨胀行为的主要因素,L605材料支架所需的临界内压力及反弹行为明显大于316L不锈钢支架;材料一定时,增加支架筋的宽度或厚度提高支架迅速扩张临界内压力;支架轴向长度的变化只与结构和最终膨胀状态相关.有限元模拟对支架性能的评价和设计有一定指导意义.

Finite element analysis of expansion behavior of coronary stents with different materials

Coronary stent is an important device used in percutaneous transluminal coronary angioplasty(PTCA),which is usually implanted to support the stenosed artery.Its expansion behavior depending on inflating of balloon and characters of recoil happening while the balloon is retrieved are the important aspects which should be concerned in operation.In this paper,the finite element method(FEM) was applied to systematically analyze the dilated mechanical behavior of 316L stainless steel and L605 stents,which is influenced by width and thickness of strut,the dilated scale of stents,vessel and stent materials used.The results show that the dilated mechanical behavior of stents depends greatly on the material used.The internal pressure needed for L605 stent to expand and recoil of L605 stent is larger than that of 316L stainless steel.And increasing strut width or thickness can improve the critical internal pressure needed for stent to expand fast.And the change of stent length while expanding is only associated with its structure and final dilatation state.In conclusion,FEM can quantify some mechanical behavior of stent and help designers to optimize stent system.