Rafiei Ashkan, Saidi Maysam
Mechanical Engineering Department, Faculty of Engineering, Razi University, Kermanshah, Iran.
Med Biol Eng Comput. 2022 Dec;60(12):3357-3375. doi: 10.1007/s11517-022-02676-z. Epub 2022 Sep 27.
The main purpose of the present numerical study is to evaluate the influences of aneurysm geometric features on the hemodynamic conditions within the left coronary arteries (LCA). Simulations have been conducted in two major parts: Section (I) encompassing three different cases (case 1, case 2, and case 3), in which three various sizes of the bifurcation region ([Formula: see text], [Formula: see text], and [Formula: see text]) were considered for each case, and Section (II) also consists of three distinct cases (case 4, case 5, and case 6) which two different positions (P and P; proximal and distal to the main bifurcation, respectively) were taken into account for a fusiform aneurysm located on their left circumflex branch. Prediction and assessment of the correlation between morphological characteristics of an aneurysm with atherosclerosis and thrombosis were performed using quantitative and qualitative results including streamline and velocity contours, wall shear stress, oscillatory shear index, and relative residence time. Depending on the various cases, the time-averaged wall shear stress (TAWSS) of the bifurcation region for models of [Formula: see text] was nearly 18-24% fewer than [Formula: see text], and around 74-81% fewer than intact models. Moreover, the smaller size of the LCA dilation results in less flow recirculation and, accordingly, the lower risk of blood clotting. Additionally, the TAWSS of the aneurysm in the P model of case 4 was found 16.4% lower than in P; however, the values for P models of case 5 and case 6 were higher than in P by close to 16.3% and 12.5%, respectively. Furthermore, it was concluded that the intricate geometry of LCAs, especially pre-aneurysm curvatures, have remarkable effects on the hemodynamics within the aneurysms. Even though a limited number of cases were used in this study, due to the scarcity of similar works, the outcomes of this computational evaluation can positively contribute to clinical decision-making in the assessment of coronary aneurysms.
本数值研究的主要目的是评估动脉瘤几何特征对左冠状动脉（LCA）内血流动力学状况的影响。模拟主要分为两个部分：第一部分（I）包含三个不同案例（案例1、案例2和案例3），每个案例考虑了三种不同尺寸的分叉区域（[公式：见原文]、[公式：见原文]和[公式：见原文]）；第二部分（II）也由三个不同案例（案例4、案例5和案例6）组成，对于位于左旋支上的梭形动脉瘤，考虑了两个不同位置（分别为P和P；主分叉的近端和远端）。使用包括流线和速度等值线、壁面剪应力、振荡剪应力指数和相对停留时间在内的定量和定性结果，对动脉瘤形态特征与动脉粥样硬化和血栓形成之间的相关性进行了预测和评估。根据不同案例，[公式：见原文]模型的分叉区域时间平均壁面剪应力（TAWSS）比[公式：见原文]模型低近18 - 24%，比完整模型低约74 - 81%。此外，LCA扩张尺寸越小，血流再循环越少，相应地，血液凝固风险越低。此外，发现案例4的P模型中动脉瘤的TAWSS比P模型低16.4%；然而，案例5和案例6的P模型的值分别比P模型高近16.3%和12.5%。此外，得出的结论是，LCA的复杂几何形状，尤其是动脉瘤前的曲率，对动脉瘤内的血流动力学有显著影响。尽管本研究中使用的案例数量有限，由于类似研究较少，但该计算评估的结果可对冠状动脉瘤评估中的临床决策做出积极贡献。
