心尖锚的力学分析

设计了一种六齿镍钛合金锚钩用于封堵器等二尖瓣、三尖瓣返流修复系统的心尖固定,并对其力学特性进行研究.通过分析心脏结构及解剖数据,确定锚钩形状和可控尺寸设计变量,利用Solidworks建立锚钩3D模型,运用Abaqus软件对23个不同尺寸锚钩模型的入鞘过程进行有限元计算,分析锚钩入鞘过程中的最大入鞘力、最大冯米塞斯应变和入鞘轨迹的影响因素.制作了一种规格锚钩实物,与计算结果进行对比分析.结果表明:鞘部长度、鞘部角度及齿宽对应力、应变的影响最大,可以通过减小鞘部长度、鞘部角度及齿宽,有效降低最大应力、应变值;厚度、曲率半径及齿宽对入鞘力起到决定性作用,而根长和角度对入鞘力的影响很小;轴向刺入深度主要通过控制鞘部长度及鞘部角度来定义,径向刺入深度则由曲率半径的大小所决定.研究可为需心尖固定的心脏介入产品设计提供一定的借鉴意义.

Mechanical analysis of apical anchors for human heart

A novel six-teeth nitinol anchor,which is used for heart apical fixation in regurgitation repairing system of mitral and tricuspid valves,was designed,and the mechanical behavior of the anchor was studied numerically.According to cardiac anatomical data,the shape and controllable geometric parameters were defined for the anchor design.3D models of the different anchor designs were built in SolidWorks,anchor sheathing process was simulated by using FEA calculations for 23 anchor designs in Abaqus.The maximum sheathing force,von Mises strain,and sheathing trajectory influencing factors were analyzed during the sheathing process.A prototype of an anchor design was fabricated and compared with the simulation results.In conclusion,the sheath length and angle as well as the tooth width have the most significant effect on the maximum stress and strain,and a short sheath length or a small angle or a narrow tooth width can lower the maximum stress and strain levels effectively.The thickness,curvature radius and tooth width are decisive in the sheathing force,while the root length and angle have a little effect on the force.The axial penetration depth is mainly determined by controlling the sheath length and angle,but the radial penetration depth is done by the curvature radius.The study could provide some reference for the design of cardiac interventional products of apical fixation.