Shu M C, Hwang N H
Medtronic Inc., Minneapolis, MN 55432.
J Biomed Eng. 1991 Mar;13(2):103-12. doi: 10.1016/0141-5425(91)90056-d.
A large percentage of arteriovenous haemodialysis angioaccess loop grafts (AVLG) fail within the first year after surgery, the occlusive lesions being found predominantly at the venous anastomosis site. This paper presents a detailed flow dynamic study of the AVLG system using three elastic, transparent bench-top flow models, which were based on the geometry of silicone rubber casts obtained at different times from a chronic animal model. Each model thus represented a different stage of the lesion development. Flow visualization and laser Doppler anemometer surveys of the flow field confirmed that the hydrodynamic factors favour lesion development near the stagnation point opposite the anastomotic toe, where the momentum of the impinging jet stream, combined with the oscillating wall shear stress generated in the vicinity of the stagnation point, acts in both directions. The accumulation of tracer particles in the region of flow separation is believed to be a combined contribution from the hydraulic forces and the inward motion of the vessel wall. As these hydrodynamic factors are enhanced upon further development of the occlusive lesion, a vicious cycle may be formed.
很大比例的动静脉血液透析血管通路袢式移植物（AVLG）在手术后的第一年内失效，闭塞性病变主要出现在静脉吻合部位。本文使用三个弹性、透明的台式血流模型，对AVLG系统进行了详细的血流动力学研究，这些模型基于不同时间从慢性动物模型获得的硅橡胶铸型的几何形状。每个模型因此代表了病变发展的不同阶段。对流场的流动可视化和激光多普勒风速仪测量证实，流体动力学因素有利于在吻合趾对面的驻点附近形成病变，在该驻点处，撞击射流的动量与驻点附近产生的振荡壁面剪应力在两个方向上起作用。示踪颗粒在流动分离区域的积累被认为是水力和血管壁向内运动的共同作用。随着闭塞性病变的进一步发展，这些流体动力学因素会增强，可能会形成恶性循环。
