Seo Taewon, Schachter Levanto G, Barakat Abdul I
Department of Mechanical and Aeronautical Engineering, University of California, Davis, CA 95616, USA.
Ann Biomed Eng. 2005 Apr;33(4):444-56. doi: 10.1007/s10439-005-2499-y.
Arterial restenosis following stent deployment may be influenced by the local flow environment within and around the stent. We have used computational fluid dynamics to investigate the flow field in the vicinity of model stents positioned within straight and curved vessels. Our simulations have revealed the presence of flow separation and recirculation immediately downstream of stents. In steady flow within straight vessels, the extent of flow disturbance downstream of the stent increases with both Reynolds number and stent wire thickness but is relatively insensitive to stent interwire spacing. In curved vessels, flow disturbance downstream of the stent occurs along both the inner and outer vessel walls with the extent of disturbance dependent on the angle of vessel curvature. In pulsatile flow, the regions of flow disturbance periodically increase and decrease in size. Non-Newtonian fluid properties lead to a modest reduction in flow disturbance downstream of the stent. In more realistic stent geometries such as stents modeled as spirals or as intertwined rings, the nature of stent-induced flow disturbance is exquisitely sensitive to stent design. These results provide an understanding of the flow physics in the vicinity of stents and suggest strategies for stent design optimization to minimize flow disturbance.
支架植入后的动脉再狭窄可能会受到支架内部及周围局部血流环境的影响。我们利用计算流体动力学来研究位于直管和弯管内的模型支架附近的流场。我们的模拟结果显示，在支架下游紧邻处存在流动分离和回流现象。在直管内的稳定流中，支架下游的流动扰动程度随雷诺数和支架丝厚度的增加而增大，但对支架丝间距相对不敏感。在弯管中，支架下游的流动扰动沿血管内壁和外壁均会出现，扰动程度取决于血管曲率角度。在脉动流中，流动扰动区域的大小会周期性地增大和减小。非牛顿流体特性会使支架下游的流动扰动略有减小。在更实际的支架几何形状中，如模拟为螺旋状或交织环状的支架，支架引起的流动扰动特性对支架设计极为敏感。这些结果有助于理解支架附近的流动物理学，并为优化支架设计以最小化流动扰动提供了策略。
