Effects of geometrical parameters on hemodynamics of arteriovenous graft: A 3D numerical simulation

Although arteriovenous grafts (AVGs) serve as a significant long-term hemodialysis access, they encounter issues such as stenosis, thrombosis, and potential graft failure. This study utilizes computational fluid dynamics to examine various combinations of geometric parameters in AVG design. Twelve looped AVG configurations are generated, including two representing commercially available AVGs. These models vary in length (60 ​mm and 150 ​mm), diameter (4 ​mm, 5 ​mm, and 6 ​mm), and venous anastomosis (VA) angles (30° and 60°). A time-dependent velocity waveform is applied at the artery inlet, with rigid walls and non-Newtonian blood modeling. AVG performance is assessed using velocity, streamlines, graft flow, and wall shear stress metrics, such as time-averaged wall shear stress, oscillatory shear index, and relative residence time. Comparative analysis identifies an AVG with a 60 ​mm length, 5 ​mm diameter, and 30° VA angle as a promising alternative to conventional graft configurations. This model demonstrates approximately 50 ​% less exposure to unfavorable hemodynamics, with a marginal decrease of around 9 ​% in maximum graft flow compared to commercial models. Shorter graft lengths, smaller diameters, and relatively smaller VA angles contribute to improved hemodynamic distribution. These findings offer insights applicable to clinical research on arteriovenous grafts and aid in developing effective therapeutic strategies.