Four 3D-models of an arterio-venous graft, a connection between an artery and a vein as vascular access for hemodialysis, were studied: One model of a conventional straight loop graft, and the others with helical design. All models were meshed with a hexahedral, structured and conformal grid. The hypothesis that the helical design reduces intimal hyperplasia formation through the reduction of unfavorable hemodynamic conditions was studied by evaluating low time average wall shear stress (TAWSS), high oscillatory shear index (OSI) and high elative residence time (RRT) zones. In all cases of the helical design, the area of low TAWSS, high OSI and high RRT is reduced. The design with modest helicity already lowered the area with high OSI, while only the strong helical design lowered the areas with low TAWSS and high RRT. It can be concluded that the areas with unfavorable hemodynamic conditions at the upper wall of the venous anastomosis can be lowered by sufficient helicity but not fully eliminated.