A numerical investigation of a stented arteriovenous fistula

An arteriovenous fistula (AVF) is a surgically created vasculature for end stage renal disease patients who require haemodialysis. The AVF is susceptible to high failure rates mainly due to the onset of intimal hyperplasia which is known to be linked to disturbed hemodynamics. One method adopted to treat this condition is to implant a flexible stent in the diseased region. In the present study, a silicone model of a patient-specific AVF was implanted with the Supera stent and subsequently scanned using a micro-CT. Using the segmentation of the high resolution scan, the AVF geometry with the stent detail was recreated and Reynolds averaged Navier Stokes simulations were conducted with pulsatile inlet flows of Reynolds numbers ranging from 345 to 730. Subsequently, two low velocity zones which translated to low wall shear stress zones were identified in the AVF. Other flow behaviour such as twisting flow from the high flow zones to low flow zones were also apparent. This study forms the basis to extend into large eddy simulations to detail the flow disturbances in the AVF to better understand the impact of the stent on the AVF health.