Wall shear stress of an end-to-side cephalic vein-to-radial artery fistula

Computational fluid dynamics has been utilized to investigate the wall shear stress characteristics of an end-to-side cephalic vein-to-radial artery fistula. The physiological flow conditions and geometry acquired from a hemodialysis patient of Taipei Veteran General Hospital are implemented. The governing equations of the CFD analysis are equations of conservation of continuity and momentum. The flow is treated as 3-D, pulsatile, laminar, Newtonian and incompressible. A validated finite volume program is employed to perform calculations. The simulation results demonstrate that the flow fields of end-to-side cephalic vein-to-radial artery fistulas can be treated as quasi-steady. High wall shear stresses occur at the junction of the A-V shunt. This conclusion contradicts the concept which low wall shear stress initiates intimal hyperplasia and atherosclerosis. Because the dimensions and flow rates of radial artery and cephalic vein change after surgical procedures, further investigations on the effects of changing flow conditions will be essential to find out the exact mechanism of the fistula failure from the hemodynamic point of view.