NUMERICAL SIMULATION OF THE EFFECT OF VENOUS NEEDLE'S FLOW RATE AND ANGLE ON FLOW PARAMETERS OF A HEMODIALYSIS GRAFT

Abstract

Arterio-Venous grafts, which are used for hemodialysis, frequently develop intimal hyperplasia in venous anastomosis which ultimately leads to graft failure. It is observed in different studies that the wall shear stress can be correlated to intimal hyperplasia development. Although high Arterio-Venous access blood flow has been implicated in the pathogenesis of graft stenosis, the role of needle's angle and flow rate during the hemodialysis procedure are relatively unexplored. Since the flow field in the region of the venous needle may be a source of damage, in the current study, a numerical investigation of the effect of venous needle's angle and flow rate on hemodynamic parameters of the flow inside a hemodialysis graft has been carried out. Five cases of different needle angles and flow rates with graft flow rate of 500 ml/min have been investigated. Results indicate that in lower angle and lower flow rates the risk of damage is less because of lower wall shear stress and more uniform shear stress distribution on graft wall.