新型导流支架治疗复杂腹主动脉瘤的血流动力学机制

The study of hemodynamic mechanism of a novel endovascular stent on complicated abdominal aortic aneurysms

目的探索新型导流支架治疗复杂腹主动脉瘤的血流动力学机制,比较多层密网支架(streamliner multilayer flow modulator,SMFM)与新型导流支架对复杂腹主动脉瘤血流动力学的影响。方法将临床采集的复杂腹主动脉瘤增强CT图像数据导入后处理软件Mimics中进行数据处理和三维重构。分别进行SMFM及新型导流支架数值建模,再导入动脉瘤数值模型,使用ICEM软件(Ansys ICEM CFD v15.0)进行网格划分后导入有限元分析软件Fluent 16.0中进行血流动力学分析。结果两种支架均可以改变瘤腔内血液流态、稳定血流,在降低瘤腔内血流速度、瘤壁压力及剪切力方面起到一定的作用,同时维持分支动脉血流通畅;与SMFM相比,新型导流支架可以更为显著的降低瘤腔内血流速度、瘤壁压力及剪切力,同时可以加快分支动脉血流速度。结论新型导流支架可以显著降低复杂腹主动脉瘤内血流速度、瘤壁压力及剪切力,同时可以加快分支动脉血流速度从而利于维持分支动脉通畅。

Objective To detect the hemodynamic mechanism of the novel endovascular stent on complicated abdominal aortic aneurysms by Computational Fluid Dynamics(CFD)firstly,and then compare the effect of the novel endovascular stent and the streamliner multilayer flow modulator(SMFM)stent.Methods All medical images were obtained by computed tomography.A semiautomatic segmentation protocol within Mimics(v17.0;Materialise,Leuven,Belgium)was used to extract the threedimensional aortic aneurysms.The stents was generated numerically and fitted along the aortic aneurysms.The lumen volume represented the fluid domain that was discretised in smaller volumes,which defined a mesh within the ICEM software(Ansys ICEM CFD v15.0).Hemodynamic analysis was performed with software Fluent 16.0.Results Both kinds of stents can change the pattern of flow distribution.Compared with SMFM,the novel endovascular stent can significantly reduce the flow velocity in aneurysms,the shear force and the pressure on the aneurysms wall.What’s more,the flow velocity of the branch artery was accelerated by the novel endovascular stent.Conclusion The novel endovascular stent can significantly reduce the flow velocity in aneurysms,the shear force and the pressure on the aneurysms wall,and acceleratethe the flow velocity of the branch artery.