Numerical Study On Characteristics Of Blood Flow In Two Vascular Accesses And Its Effects On Vessel

Understanding of the characteristics of blood flow and the response of the vessel is important to select and improve treatment regimes. Due to the complexity of blood flow and difficulties in vivo experiments, there is still a gap between research results and the clinical needs in this area. In this paper, the characteristics of blood flow in two common surgeries, i.e. arteriovenous fistula and deep venous catheter, were studied numerically.In the late stage of renal dysfunction, hemodialysis is an important method for patients to survive, and proper vascular access is the key for successful hemodialysis treatment. In generally, autogenous arteriovenous fistula is the best vascular access. However, arteriovenous fistula will change the original blood flow, and may cause the vessel wall intimal hyperplasia. Assuming the vessel being rigid and considering the non-Newtonian fluid property and unsteady characteristics of blood flow, the finite volume method was applied to simulate the effect of arteriovenous fistula on blood flow. The results show that there is a complex vortex in the fistula, which results in small wall shear stress on the vessel near the fistula. As the distance to the fistula becomes shorer, the distribution of wall shear stress becomes more uneven and the vessel becomes more unstable. These may be an important reason for the venous anastomotic intimal hyperplasia.Due to the poor vascular conditions, arteriovenous fistula can not be estabished for some old or cardiac insufficiency patients, Venous catheter is a good choice for these patients. However, poor blood flow or intimal hyperplasia may also lead to failure of the catheter. In this paper, the blood flow around the catheter was simulated. The results show that the distribution of wall shear stress on the vessel near the catheter side holes is very uneven. The simulation results and the experimental results of other researchers implies that intimal hyperplasia may be affected by the uneven distribution of wall shear stress.