An Attempt to Develop a Numerical Tool for the Prediction of Stenosis in Arteriovenous Fistula for Hemodialysis

An arteriovenous fistula (AVF) is a vascular connection between a vein and an artery, surgically created as access for hemodialysis. This connection enables high blood flow through the vein. The main reason for AVF failure is stenosis, which may restrict the blood flow below the minimum required for hemodialysis. Wall shear stress (WSS) plays a major role in regulating endothelial cells behavior which causes stenosis.

The goal of this study is to find the correlation between the stenotic location in AVF with the appropriate hemodynamic wall parameters (HWPs) for a patient-specific (PS).

A special ultrasound system is used to acquire a three-dimensional geometry of the AVF for each patient. Patients are monitored every few months.

If stenosis sites are identified in one of the patients, we examine these sites from previous ultrasound samples. We perform a numerical analysis on the AVF to obtain the HWPs using ANSYS. Then we look for parameters which can indicate a future stenosis occurrence such as OSI and RRT.

In a model of AVF with ideal geometry, calculated OSI patterns, were consistent with previous results, which demonstrated specific sites of stenosis in the AVF. WSSs obtained in PS fistula, were higher than WSSs obtained in cases of ideal geometry.

In further work we’ll try to identify the HWPs that correlate with stenosis. This can contribute to the development of a predictive tool for stenosis.