Image-based modeling of arteriovenous hemodialysis access graft flow

Thrombosis in an arteriovenous hemodialysis access graft is a major cause of graft failure. Changes in flow features due to increasing resistance at the venous anastomosis may promote the development of thrombosis. A three-dimensional computational fluid dynamics model was developed to analyze flow at the arterial anastomosis of a PTFE brachial-brachial arteriovenous access graft. The geometry was obtained from contrast-enhanced magnetic resonance images. A surface mesh was extracted using Amira software, and the final volume mesh was generated by Tgrid (Fluent, Inc). The simulation was carried out for steady flow conditions using Fluent CFD software with low-Reynolds number k-omega turbulence model. Small areas of recirculation can be seen in the area of the bifurcation, and results show a pressure difference between the proximal artery and the graft that is consistent with reported values.