1.太原理工大学 生物医学工程学院;2.太原理工大学 机械与运载工程学院;3.解放军总医院第一医学中心血管外科
目的 采用数值模拟的方法研究模块化内嵌分支支架（Modular Inner Branched Stent Graft，MIBSG）形态特征对术后支架内血流动力学特征的影响，为临床制定术前方案和评估术后疗效提供依据。方法 建立模块化内嵌分支支架模型，通过求解血流-血管壁流固耦合模型，对比分析了形态参数，如分支支架的分支角度和管径，以及流速、支架内壁的应力、位移、出口流量比等力学参数对主动脉弓血流动力学特征的影响。结果 随着分支支架与主动脉弓支架之间的角度增大，分支横截面形成两个反方向涡的对称性降低。导致分支内的血流量会降低，受到的应力和产生的位移相应增大。分支支架的管径减小，血流量灌注会显著下降，应力和位移却先下降后上升。结论 理想化MIBSG模型是研究血流-支架流固耦合作用的有力工具，因为它是完全参数化的，其几何形态可以任意调整，从而可以详尽地研究各个参数对于血流动力学特征的影响。这是理想化支架模型相对于三维重建的真实支架模型的一个优点。本文基于该模型的研究结果可为模块化内嵌式支架参数确定、手术方案制定、术后有效性和安全性评估提供一定参考。
Objective To study the effect of the morphologic characteristics of Modular Inner Branched Stent Graft (MIBSG) on the hemodynamics of postoperative aortic arch by numerical simulation, aiming to provide certain theoretical guidance for the determination of modular embedded stent parameters, surgical programming, postoperative effectiveness and safety assessment. Methods CAD models of MIBSG with various branch angle and diameter were established. Then, the fluid – structure interaction (FSI) between blood – MIBSG is solved numerically. Based on the numerical results, the effects of kinds of parameters, i.e., morphological parameters such as the angle between the branch stent, the diameters of stents, and hemodynamic quantities such as velocity, von Mises stress, displacement of the inner wall and outlet flow rate ratio on the hemodynamic characteristics are investigated. Results The results show that as the angle between the branch stent and the aortic arch stent increased, the blood flow within the branch decreased, but the stress and displacement increased. Different from the change of angle, the change of the diameter of the branching stent has more influence on the hemodynamic parameters. With the decrease of the diameter of the stent, the blood flow perfusion would decrease significantly, but the stress and displacement of the branching stent show a different tendency, that is, they increase first, followed by decrease. Conclusions The idealized MIBSG stent model is a useful tool to investigate various parameters’ effect on the hemodynamic characteristics of blood flow, for that the idealized model is fully parameterized and its geometric characteristics is tunable, so the effect of a parameter on the hemodynamic characteristics should been investigated in detail. This is an advantage of idealized parameterized MIBSG compared to the three-dimensional reconstructed stent model based on CT images. Based on this model, the results of this study are of great significance to the establishment of a complete personalized diagnosis and treatment integration scheme, such as modular inline stent preoperative evaluation, surgical planning, in-service navigation and postoperative risk prediction.