含有镍钛合金丝的PET纺织瓣膜有限元分析及体外流体力学测试

目的 利用有限元方法分析径向织入镍钛金属丝的涤纶(polyethylene terephthalate, PET)基纺织瓣膜力学性能，结合体外血流动力学测试，分析金属丝数量和分布形式对PET瓣膜流体动力学性能的影响。方法 使用建模软件构建在径向方向上具有不同数量和分布的金属丝PET瓣膜和无金属丝PET瓣膜三维几何模型；根据文献和实验数据给定PET瓣膜和金属丝的材料属性；使用体外脉动流实验得到PET瓣膜的跨瓣压差曲线作为边界条件；利用有限元分析软件研究瓣膜在心动周期内的应力分布；通过体外脉动流实验评估金属丝瓣膜的流体力学性能。结果 有限元分析结果表明，径向织入镍钛金属丝可以增强对PET纺织瓣膜的支撑作用，金属丝均匀分布的瓣膜在瓣叶腹部区域的支撑力及作用区域随着金属丝数量增加而增大，金属丝分布在两侧位置的情况类似。金属丝的织入一定程度上改善PET瓣膜上的应力集中。脉动流实验结果表明，织入金属丝PET瓣膜开闭形态的稳定性、有效开口面积、反流分数和跨瓣压差等指标均优于无金属丝的纯PET瓣膜。结论 在PET纺织瓣膜的径向方向织入金属丝可以有效减少心动周期内PET纺织瓣膜上的应力集中，降低PET纺...

Finite Element Analysis and in vitro Hemodynamic Testing of Polyester Textile Valves with Nitinol Wires

Objective To study mechanical properties of polyethylene terephthalate (PET)-based textile valves woven with nickel-titanium (NiTi) wires by finite element method, and combined with in vitro hemodynamic testing, to analyze the effect of wire quantity and woven position on hemodynamic performance of PET textile valve. Methods The three-dimensional (3D) geometric models of PET valves without wires and models of PET valves with wires by different numbers and distributions in radial direction were constructed using modeling software. Material properties of PET valves and wires were given based on the literature and experimental data. The transvalvular pressure difference curves of PET valves obtained from in vitro pulsatile flow experiments were used as boundary conditions. Stress distributions of the valve during peak systole and diastole were studied by finite element analysis software. Hydrodynamic performance of the valve with wires was evaluated by in vitro pulsatile flow experiments. ResultsThe finite element analysis results showed that the radially woven NiTi wires could enhance support for the PET textile valve, and support force and area of the valve in belly region of the valve leaflet with evenly distributed metal wires increased with the number of metal wires. The situation of support force was similar for silk distributions on both sides of the belly. The weaving of wires reduced stress concentration on the PET textile valve to a certain extent. The pulsatile flow experiment results showed that the stability of opening and closing shapes, effective opening area (EOA), regurgitation fraction (RF) and transvalvular pressure differences for two kinds of the PET valves with woven wires were better than those of the PET valves without wires. Conclusions Weaving metal wires in radial direction of the PET textile valve can effectively reduce stress concentrations on the PET textile valve during the cardiac cycle, and reduce tearing possibility of the valve leaflet. The woven metal wires can improve opening and closing stability of PET textile valve in in vitro hydrodynamic test, increase EOA and reduce RF and transvalvular pressure difference of the PET valve.