中文摘要：

目的探讨支架置入椎动脉开口处狭窄后突出到左锁骨下动脉的距离对局部血流动力学的影响。方法分别构建未置入支架（模型1）以及置入支架无下移（模型2）、下移1mm（模型3）、2mm（模型4）、3mm（模型5）的椎动脉模型。利用计算流体力学方法进行数值模拟，比较不同模型的血流流速、壁面切应力等血流动力学差异。结果支架置入术后，模型2的支架段壁面切应力降低85．33％、血流速度降低35．36％、旋动流现象消失。支架下移不同程度的几个模型相比，狭窄段的壁面切应力相差最大0．76％、血流速度相差最大0．45％。结论支架的置入椎动脉开口狭窄后的血流动力学变化显著，而支架下移距离对椎动脉流速和壁面切应力的影响不明显。

英文摘要：

Objective To investigate the influence of different protrusion distance of stent strut into the subclavian artery on local hemodynamics of the vertebral artery （VA） ostium. Methods Five models of the VA were estab- lished. Model 1 was without stent implantation, Model 2 to ,5 was with stent protruding into the subclavian artery for O, 1,2, 3 mm, respectively. Computational fluid dynamics analysis was performed to study the differences of hemodynamics in these models. Results After stent implantation, the wall shear stress and the blood flow veloc- ity at the stent segment in the Model 2 was reduced by 8.5.33% and 35.36%, respectively. The phenomenon of swirling flow disappeared. For models with different protrusion distance, the maximum difference of wall shear stress of VA was 0.76%, and the maximum difference of blood flow velocity is 0.45%. Conclusions Stent im- plantation can improve the hemodynamics of vertebral artery ostium stenosis, while the protrusion distance of stent strut has no obvious influence on the blood flow velocity and wall shear stress.