Comparison of Two Different Arteriovenous Anastomotic Forms By Numerical 3D Simulation of Blood Flow.

Anastomotic intimal hyperplasia caused by unphysiological hemodynamics is generally accepted as a reason for dialysis access graft occlusion. Optimizing the venous anastomosis can improve the patency rate of arteriovenous grafts. The purpose of this study was to examine, evaluate and characterize the local hemodynamics, and in particular, wall shear stresses in conventional venous end-to-side anastomosis and in patch form anastomosis (Venaflotrade mark) by Computational Fluid Dynamics (CFD). The flow simulations were carried out as three-dimensional to extend results of our previous 2D studies. The numerical simulation was done with a finite volume-based algorithm. The anastomotic forms were constructed with usual size and fixed walls. Subdividing the flow domain into multiple control volumes solved the fundamental equations. The boundary conditions were constant for both forms. The velocity profile of the patch form is better than for the conventional form. The region of high static pressure caused on flow stagnation is reduced on the vein floor. The anastomotic wall shear stress is decreased. The results of this study strongly support patch form use to reduce the incidence of intimal hyperplasia and venous anastomotic stenoses.