曾堃 乔爱科

中文摘要:
      目的 提出不同于传统支架的三角形网丝截面支架，并对其进行数值模拟，比较圆形、矩形、三角形截面支架在动脉瘤内的血流动力学效果。方法 构建3个有支架植入的动脉瘤模型，分别为圆形（CM型）、矩形（RM型）和三角形（TM型）截面支架模型，并与1个无支架的动脉瘤模型（UM型）对照。在相同的边界条件下，利用有限单元法对4个模型进行流固耦合数值模拟。结果 RM型比TM型和CM型的速度更低、流阻更高、流转时间更长，所以矩形、三角形、圆形截面支架血液流动的影响效果依次降低。在削弱壁面切应力大小、降低壁面切应力波动性方面，RM型比TM型和CM型更加显著，但CM型和TM型的壁面升压低于RM型。壁面应力分布和变形结果表明动脉瘤沿远侧壁生长的可能性大于近侧壁，瘤顶破裂的风险最大。结论 3种截面支架展示了不同的血流动力学，这些结果为血管内支架的结构设计和优化提供了有意义的参考依据。
英文摘要:
      Objective To propose and numerically simulate a novel stent with triangular wire cross-section so as to compare the hemodynamic effect of endovascular stents in aneurysm with circular, rectangular and triangular crosssection, respectively. Methods Three aneurysm models were constructed by implanting 3 kinds of stents separately, including one with bare circular wire cross-section stent (named CM), and one with bare rectangular wire cross-section stent (named RM), and one with bare triangular cross-section stent (named TM). An unstented aneurysm model was also constructed to serve as the control (named UM). Four models were preformed with numerical simulation of fluid-structure interaction under the same boundary conditions using finite element method. Results Compared with TM and CM, RM showed lower velocity, higher flow resistance and longer turn over time, which demonstrated that the effect of blood flow pattern on three stents was decreased in the order of RM, TM, CM. RM could reduce the magnitude and fluctuation of wall shear stress (WSS) more significantly than that of TM and CM. However, the pressure rise of TM and CM was lower than that of RM. WSS distribution and deformation results indicated the possibility of aneurysm development along the distal wall was higher than that along the proximal wall, and the top of aneurysm was in the highest risk of rupture. Conclusions Three kinds of stents show differences of hemodynamics in aneurysm treatment, which provides significant references for the structural design and optimization of endovascular stent.