Numerical evaluation and experimental validation of vascular access stenosis estimation.

Vascular access dysfunction commonly occurs in hemodialysis patients. Regularly monitoring and evaluating the vascular access condition is an important issue for these diseased patients. The objective of this study was to identify acoustic parameters and hemodynamics that related to changes in the stenosis of vascular access. In-vitro experimental circulation system offered pulsatile and physiological condition to simulate the arteriovenouse access in hemodialysis patient. We created the environments of various degrees of stenosis (DOS) inside the arteriovenouse access to simulate the stenotic conditions in patients. And we also used the computational fluid dynamics (CFD) to simulate the pressure distribution, primary axial velocity distribution, and secondary flow distribution in the same various DOS and boundary condition. There are two findings, one is recorded the bruit which caused by the fluctuation of fluid in different severe stenosis, the other is described the correlation between bruit and hemodynamic parameters. Experimental results show the time constants have linear regression with a positive correlation as the degree of stenosis (DOS) increases. Finally, in contrast to CFD computerized analysis and acoustic methods, the proposed parameter provides a feasibility index for evaluating the risk of AVG dysfunction in on-line/real time analysis.