Department of Mechanical Engineering, School of Engineering, Hellenic Mediterranean University, Heraklion, Crete, Greece.
Vascular Surgery Department, Medical School, University of Crete, Heraklion, Crete, Greece.
Clin Hemorheol Microcirc. 2024;87(2):199-219. doi: 10.3233/CH-232058.
To compare the hemodynamic performance of three (Bottom Up non-ballet, Top-Down non-ballet, Top Down ballet) idealized stent graft configurations used during endovascular repair of abdominal aortic aneurysms, under the influence of various rheological models.
Ten rheological models are assumed and a commercial finite volume solver is employed for the simulation of blood flow under realistic boundary conditions. An appropriate mesh convergence study is performed and five hemodynamic variables are computed: the time average wall shear stress (TAWSS), oscillatory shear index (OSI), relative residence time (RRT), endothelial cell activation potential (ECAP) and displacement force (DF) for all three configurations.
The choice of blood flow model may affect results, but does not constitute a significant determinant on the overall performance of the assumed stent grafts. On the contrary, stent graft geometry has a major effect. Specifically, the Bottom Up non-ballet type is characterized by the least favorable performance presenting the lowest TAWSS and the highest OSI, RRT and ECAP values. On the other hand, the Top Down ballet type presents hemodynamic advantages yielding the highest TAWSS and lowest OSI, RRT and ECAP average values. Furthermore, the ballet type is characterized by the lowest DF, although differences observed are small and their clinical relevance uncertain.
The effect of the assumed rheological model on the overall performance of the grafts is not significant. It is thus relatively safe to claim that it is the type of stent graft that determines its overall performance rather than the adopted blood flow model.
比较三种（底部向上非芭蕾舞式、顶部向下非芭蕾舞式、顶部向下芭蕾舞式）理想化支架移植物构型在腹主动脉瘤血管内修复过程中的血流动力学性能，在各种流变学模型的影响下。
假设了十种流变学模型，并采用商业有限体积求解器模拟真实边界条件下的血流。进行了适当的网格收敛性研究，并计算了所有三种构型的五个血流动力学变量：时间平均壁切应力（TAWSS）、振荡剪切指数（OSI）、相对驻留时间（RRT）、内皮细胞激活潜能（ECAP）和位移力（DF）。
血流模型的选择可能会影响结果，但不是支架移植物整体性能的重要决定因素。相反，支架移植物的几何形状有很大的影响。具体来说，底部向上非芭蕾舞式的性能最差，表现为最低的 TAWSS 和最高的 OSI、RRT 和 ECAP 值。另一方面，顶部向下芭蕾舞式呈现出血流动力学优势，产生最高的 TAWSS 和最低的 OSI、RRT 和 ECAP 平均值。此外，芭蕾舞式的 DF 最低，尽管观察到的差异较小，其临床相关性不确定。
所假设的流变学模型对移植物整体性能的影响并不显著。因此，可以相对安全地声称，是支架移植物的类型决定了其整体性能，而不是采用的血流模型。
