Assessment of an Arterial Stiffness to Demonstrate AVF Performance: Modelling Approach

Abstract

Arteriovenous fistula (AVF) defined as shunting in the arterial system and the venous conduit is a preferred vascular access used in haemodialysis. The AVF provide a sufficient increase in blood flow rates for effective dialysis. However maintaining AVF patency become the greatest challenge for dialysis patient. Complications arise from this includes stenosis, aneurism and thrombosis. In previous studies, several methods are used to evaluate the performance of AVF. This study will focus on the assessment of arterial stiffness to demonstrate the performance of a side-to-side AVF. The condition of arterial stiffness which alter haemodynamic of AVF, in fact, will affect its performance and functionality. To gain insight and understanding for the haemodynamic condition, a healthy AVF (without arterial stiffening) has been modelled in the computational fluid dynamic (CFD) framework. The aim of this project is therefore to develop a modelling approach, suitable for the analyses of blood flow field to predict the performance and patency of AVF. A 3D CFD method is proposed to analysis flow field or haemodynamic in terms of blood flow velocity, blood pressure and wall shear stress (WSS) along the AVF. A laminar flow was introduced for the simulation of healthy AVF. Correlations in these haemodynamic parameters to assess the vascular failure supports hypothesis suggesting flow field as predicator for AVF performance. Haemodynamic effects lead to AVF failure were determined. Significant flow disturbances with abnormally high or low WSS obtained from the simulation is used as a primary indicator.