半圆形截面支架介入串联囊状动脉瘤的血流动力学仿真

Hemodynamics Simulation of Intervention for Serial Saccular Aneurysm with Semi-circular Section Stent

为了研究半圆形截面支架对颅内串联囊状动脉瘤血流动力学的影响,针对同一动脉瘤结构,构建无支架和4种截面支架介入动脉瘤的有限元模型,分别命名无支架为U型、圆形截面为C型、半圆形截面圆面朝向瘤腔为ES型、圆面朝向血管轴向为IS型,然后对模型中的生理脉动流进行计算流体动力学仿真。数值模拟的结果显示:有支架模型的腔内流速被有效削弱,壁面附近的流速很低;血流对瘤腔的冲击减弱,壁面切应力的量值和波动性降低,分布均衡;腔内压力在支架介入后略有升高。对比分析两个瘤腔,流动情况和壁面切应力基本相同,下游瘤腔的压力低于上游瘤腔。IS型的仿真结果更好,这为支架的结构设计提供了一些理论指导。

In order to investigate the hemodynamic effect of intervention for intracranial serial saccular aneurysm with semi-circular section stent,four finite element models of serial saccular aneurysms were constructed. These models were one model without stent intervention （U-type） and three models with bare stent intervention, including one with circular section stent （C-type ） , one with semi-circular section stent whose circular arch faces towards the aneurismal cavity （ ES-type） and one with semi-circular section stent whose circular arch faces towards the vascular center （IS-type）. Computational fluid dynamics simulations of physiologically pulsatile blood flow in these models were performed. Velocity of blood flow in stented models were effectively weakened, and velocity near aneurismal wall was very low. Impact of blood flow on aneurysm was weakened because of stent intervention. Magnitude and fluctuation of wall shear stress were reduced, and the distribution of wall shear stress was more balanced. Pressure in aneurysm was almost not changed,and the pressure of stented models was slightly increased. Comparison analysis of the two aneurismal cavities demonstrated that the flow and wall shear stress were basically same, and the pressure of the distal cavity was lower than the proximal one. The simulation result showed that IS-type was the best. These results could provide some theoretical guidance to structural design of endovascular stent.