支架植入颅内蜿蜒型动脉瘤的血流动力学仿真

Simulation of hemodynamics in stent Intervention of basilar sinuous aneurysms

目的构建蜿蜒型动脉瘤和弯曲支架三维有限元模型,研究支架植入动脉瘤后的血流动力学的变化。方法通过CAD软件构建出几何实体模型,借助有限元软件利用计算流体力学方法,分别对无支架和有支架的蜿蜒型脑动脉瘤定常流动血流动力学进行数值模拟,分析在动脉瘤中植入内支架前后的瘤腔内流动情形、压力和壁面切应力分布的变化情况。结果有支架动脉瘤模型上游瘤腔内的血流速度被大大削弱,圆顶突起处局部高压力明显减弱,在下游瘤腔沿壁面的压力也得到明显降低并且分布也均衡了很多,末端唇缘处局部高切应力消失了,出现的是较小且均衡的切应力。结论有支架模型瘤腔内的流速明显减小,均衡的压力分布与瘤腔内减弱的流动速度是相互统一的,利于瘤腔内血栓的形成。

Objective Study the changes of hemodynamics after stent intervention to sinuous aneurysms. Method Geometrically idealized model of three-dimensional sinuous aneurysms and curved stent was constructed using CAD software. Numerical simulations of stented and nonstented models were performed respectively in steady flow according to CFD method using finite element software. Hemodynamics data in the two models were compared in terms of flow field, pressure and the distribution of Wall Shear Stress （WSS）. Result Velocity of blood flow in stented model is greatly weaken than the nonstented, and the local high pressure is markedly decreased at the proximal aneurismal dome, and the pressure along the wall of the distal aneurysm is also decreased and more uniform. The local elevated WSS atthe proximal lip of the distal an- eurysm disappeared after stent intervention, instead small and uniform WSSs distribute along a majority of the aneurismal wall. Conclusions Velocity of flow is obviously depressed after stent intervention, and the counterpoised pressure distribution of the stented model is more uniform with the weakened flow velocity in the aneurysm cavity, which are beneficial to the thrombus formation in the aneudsmal cavity.