Nada Ayat, Hassan Mohammed A, Fakhr Mahmoud A, El-Wakad Mohamed Tarek I
Department of Computers and Systems, Electronics Research Institute, Giza, Egypt.
Department of Biomedical Engineering, Faculty of Engineering, Helwan University, Cairo, Egypt.
J Med Eng Technol. 2021 Jul;45(5):408-416. doi: 10.1080/03091902.2021.1912204. Epub 2021 May 4.
This study investigates the effect of stent thickness and stent porosity which are important factors determining the post-treatment intra-aneurysmal hemodynamics. The study uses computational fluid dynamics (CFD) to estimate the hemodynamic behaviour: flow velocity, pressure distributions, time-averaged wall shear stress (TAWSS), oscillatory shear index (OSI), besides relative residence time (RRT) blood flow distribution in a proposed stent and three other commercially available stents. The hemodynamic behaviour is compared between four different cases. In each case, each stent has the specific thickness and porosity values. The results show that the velocity magnitude inside the sac declined in thinner stents and lower porosity stents, TAWSS on the aneurysmal wall declined linearly in lower porosity stents, OSI and RRT increased obviously in thicker stents and higher porosity stents. Finally, the results conclude that the stent with the lowest thickness and porosity has the best performance that leads to post-stent thrombus formation and healing. However, the proposed stent design, a more porous construct, has a higher RRT compared to the used commercially available stents, which helps promote the thrombus growth inside the aneurysm sac.
本研究调查了支架厚度和孔隙率的影响，这两个因素是决定治疗后动脉瘤内血流动力学的重要因素。该研究使用计算流体动力学（CFD）来估计血流动力学行为：流速、压力分布、时间平均壁面切应力（TAWSS）、振荡切应力指数（OSI），以及在所提出的一种支架和其他三种市售支架中的相对停留时间（RRT）血流分布。对四种不同情况的血流动力学行为进行了比较。在每种情况下，每个支架都有特定的厚度和孔隙率值。结果表明，在较薄的支架和较低孔隙率的支架中，瘤腔内的速度大小下降，在较低孔隙率的支架中，动脉瘤壁上的TAWSS呈线性下降，在较厚的支架和较高孔隙率的支架中，OSI和RRT明显增加。最后，结果得出结论，厚度和孔隙率最低的支架具有最佳性能，可导致支架后血栓形成和愈合。然而，所提出的支架设计，即一种孔隙率更高的结构，与使用的市售支架相比具有更高的RRT，这有助于促进动脉瘤腔内血栓的生长。
