Ha Hojin, Choi Woorak, Lee Sang Joon
Department of Mechanical Engineering, Pohang University of Science and Technology, San 31, Hyoja-dong, Pohang 790-784, Republic of Korea.
Department of Mechanical Engineering, Pohang University of Science and Technology, San 31, Hyoja-dong, Pohang 790-784, Republic of Korea; Center for Biofluid and Biomimic Research, Pohang University of Science and Technology, San 31, Hyoja-dong, Pohang 790-784, Republic of Korea.
Med Eng Phys. 2015 Mar;37(3):272-9. doi: 10.1016/j.medengphy.2015.01.007. Epub 2015 Feb 7.
Although a large number of vascular grafts are surgically implanted annually, approximately 10-15% of these grafts fail in the first year after operation and about 50% are only effective for five to ten years. Surgical implantation of a vascular graft modifies the inherent hemodynamic environment in blood vessels; hence, fluid dynamic characteristics of pathological blood flow are highly related to the performance of the vascular graft. In this study, pathological fluid-dynamic characteristics in a 45° end-to-side anastomosis were experimentally investigated using a particle image velocimetry technique. In particular, the effect of the pulsatile swirling inlet flow in the vascular graft on the improvement of pathological hemodynamic features was systematically investigated. Introducing the pulsatile swirling flow equalizes the asymmetric distribution of wall shear stress and reduces oscillatory shear index and the size of flow separation because the flow disturbs the formation of Dean-type vortices and suppresses secondary flow collision. The fluid dynamic features of the pulsatile swirling flow are expected to be beneficial in designing vascular grafts that can suppress pathological hemodynamic characteristics in the recipient host vessel.
尽管每年都有大量的血管移植物通过手术植入，但这些移植物中约有10%-15%在术后第一年失败，约50%仅在五到十年内有效。血管移植物的手术植入改变了血管内固有的血流动力学环境；因此，病理性血流的流体动力学特性与血管移植物的性能高度相关。在本研究中，使用粒子图像测速技术对45°端侧吻合处的病理性流体动力学特性进行了实验研究。特别是，系统地研究了血管移植物中脉动旋转入口流对改善病理性血流动力学特征 的影响。引入脉动旋转流可使壁面剪应力的不对称分布均匀化，并降低振荡剪应力指数和流动分离的大小，因为该流动会干扰迪恩型涡的形成并抑制二次流碰撞。脉动旋转流的流体动力学特性有望有助于设计能够抑制受体宿主血管中病理性血流动力学特征的血管移植物。
