Department of Bioengineering and Robotics, Graduate School of Engineering, Tohoku University, Aramaki-Aza Aoba 6-6-4, Aoba-ku, Sendai, Miyagi, 980-8579, Japan.
Institute of Fluid Science, Tohoku University, Katahira 2-1-1, Aoba-ku, Sendai, Miyagi, 980-8577, Japan.
Med Biol Eng Comput. 2019 Jan;57(1):15-26. doi: 10.1007/s11517-018-1864-6. Epub 2018 Jul 2.
The stent geometrical design (e.g., inter-strut gap, length, and strut cross-section) is responsible for stent-vessel contact problems and changes in the blood flow. These changes are crucial for causing some intravascular abnormalities such as vessel wall injury and restenosis. Therefore, structural optimization of stent design is necessary to find the optimal stent geometry design. In this study, we performed a multiobjective stent optimization for minimization of average stress and low wall shear stress ratio while considering the wall deformation in 3D flow simulations of triangular and rectangular struts. Surrogate-based optimization with Kriging method and expected hypervolume improvement (EHVI) are performed to construct the surrogate model map and find the best configuration of inter-strut gap (G) and side length (SL). In light of the results, G-SL configurations of 2.81-0.39 and 3.00-0.43 mm are suggested as the best configuration for rectangular and triangular struts, respectively. Moreover, considering the surrogate model and flow pattern conditions, we concluded that triangular struts work better to improve the intravascular hemodynamics. ᅟ Graphical abstract.
支架的几何设计（例如，支架间的间隙、长度和支架的横截面）会影响支架与血管壁的接触问题以及血流的变化。这些变化对血管壁损伤和再狭窄等一些血管内异常的发生至关重要。因此，需要对支架设计进行结构优化，以找到最佳的支架几何设计。在这项研究中，我们在三角形和矩形支架的三维流动模拟中，通过考虑壁面变形，进行了平均应力和低壁面剪切应力比最小化的多目标支架优化。利用克里金方法和期望超体积改进（EHVI）的基于代理的优化来构建代理模型图，并找到最佳的支架间间隙（G）和边长（SL）配置。结果表明，对于矩形和三角形支架，建议的最佳 G-SL 配置分别为 2.81-0.39 和 3.00-0.43mm。此外，根据代理模型和流动模式的条件，我们得出结论，三角形支架可以更好地改善血管内血流动力学。ᅟ 图形摘要。
