不同支撑杆数目腔静脉滤器的生物力学性能和血流动力学分析

目的利用有限元与计算流体动力学的方法,分析不同支撑杆数目腔静脉滤器在植入过程中与血管的相互作用机制及对血流的影响,为滤器的临床治疗及设计开发提供更加科学的参考。方法应用Solidworks软件建立支撑杆数分别为4、6和8杆的3种滤器模型;应用ABAQUS软件模拟分析3种滤器在工作状态下血管与滤器表面上的应力分布以及径向支撑刚度;应用Fluent软件模拟分析3种滤器在血管内工作时血流流速、压力、剪应力的分布。结果 3种滤器的各项力学性能和流体性能都在安全范围内。6杆滤器的综合性能相对较好;8杆滤器工作时所受应力、支撑强度、出口速度、过滤网上的剪应力均较大,流迹状态逐渐由层流向过度流变化,容易造成血管壁的损伤;4杆滤器在工作时对血管的应力较大,出口速度较低,容易造成局部血管壁的损伤,并且不利于滤器在血管病变部位的正确定位。结论 6杆滤器具有较好的血流动力学效果和综合力学性能,潜在降低了滤器植入后对血管壁的损伤及本身破裂的可能性。腔静脉滤器的模拟分析为滤器的设计和临床选择提供良好的参考依据。

Analysis on biomechanical properties and hemodynamics of the vena cava filters with different numbers of support bars

Objective To investigate the interaction between vessel and vena cava filter (VCF) with different numbers of support poles and the influence on blood flow during its implantation by using finite element method and computational fluid dynamics method, so as to provide more scientific guidance for intervention treatment and design & development of the filter. Methods Three kinds of VCF models with 4, 6, 8 support poles were established by using Solidworks, respectively. The stress distribution and radial support stiffness of the vessel and filter under working condition were then simulated and analyzed by using ABAQUS. The distributions of blood flow velocity, pressure and shear stress after VCF implantation were simulated by using Fluent. Results All the mechanical and fluid properties of the three kinds of VCFs were within the scope of security. The comprehensive mechanical performance of the 6-pole filter was better, while for the 8 pole-filter, it showed larger stress under working condition, larger support intensity, higher exit velocity, larger shear stress on the filter mesh, and the trail of the flow was changed from laminar to transition flow, which might cause some damage to the vessel wall. The 4 pole-filter under working condition had a larger stress on the vessel, while its exit velocity was lower, which could be likely to cause local damage on the vessel wall, and disadvantageous to accurately positioning the filter in diseased region of the vessel. Conclusions The 6 pole-filter has a superior hemodynamic effect and comprehensive mechanical properties, which reduces the potential possibility of damage to the vessel wall caused by implantation of the filter. The simulation analysis on VCF provides a good reference for design of the filter and its intervention treatment in clinic.