主动脉及分支血管支架植入后血流动力学分析

Hemodynamics Analysis of a Stented Aortic Bifurcation

当主动脉夹层累及左侧锁骨下动脉时,有时需要植入两枚支架对主干和分支血管同时进行治疗。本研究应用Pro/engineer wildfire3.0建立人体主动脉弓及其分支模型并模拟支架植入,依据主干内支架杆突入左锁骨下动脉开口处情况不同建立3种模型,以未植入支架的正常主动脉弓为对照组,应用ANSYS11.0 CFX软件分别进行计算流体力学分析,比较支架杆突入左锁骨下动脉开口情况不同对分支血管血流速度及血管壁面剪切力影响的差异。结果发现:突入左侧锁骨下动脉开口的支架杆引起分支动脉中血流速度明显减慢及大范围低剪切力区形成,文献报道这种低速、低剪切力环境可能促使血栓形成和内膜增生,导致支架内再狭窄,故有必要使用专门的预成型分支型主动脉支架治疗累及左锁骨下动脉的主动脉夹层动脉瘤。

In the treatment of aortic arch dissections involving left subclavian artery（LSA）, a double stent implantation is sometimes required to treat the disease of each branch. In this study, aortic arch and LSA were modeled by using Pro/engineer wildfire3.0. Two deployed stents were inserted in the aortic arch and LSA. There are 3 kinds of model according to the stent struts protruding into the inlet of the collateral branch,and the healthy aortic arch model without any stent was provided as a reference case. We used computational fluid dynamics （CFD） to investigate the flows in the model stents and focused on the changes of blood speed and wall shear stress caused by the implanted stents of different models. The results showed that the stent strcuts protruding into the inlet of LSA induced the conspicuous decrease of blood speed and the emergence of large-scale low shear stress,which would cause thrombogetaesis,neointimal hyperplasia and result in in-stent restenosis, so it would be judicious to use dedicated bifurcated stents for treatment of bifurcation lesions.