Endpoints for Hemodialysis Access Procedures: Correlation between Fistulography and Intraaccess Blood Flow Measurements

Abstract

Purpose The success of percutaneous interventions on stenotic hemodialysis prosthetic grafts and autogenous fistulas is assessed by comparing vessel diameter before and after treatment. These changes do not correlate with gold standard access blood flow (ABF) measurements obtained during hemodialysis. The AngioFlow (AngioDynamics, Inc, Queensbury, New York) calculates real-time blood flow through access circuits and may provide more physiologically relevant data in the interventional suite. This study compares angiographic vessel diameter and access circuit flow rates obtained with the AngioFlow Meter before and after percutaneous interventions on stenotic hemodialysis prosthetic grafts and autogenous fistulas ABF measurements obtained during hemodialysis. Materials and Methods Angiographic images and AngioFlow measurements for 76 procedures in 35 patients undergoing hemodialysis with arteriovenous grafts or fistulas were analyzed retrospectively. Correlations between ABF, fistulography, and AngioFlow measurements before and after treatment were computed. Regression analyses of AngioFlow measurements and measurements after ABF were performed to account for confounding factors. Time to failure of treatment was modeled in first-time patients stratified by AngioFlow values obtained after treatment. Only patients with ABF measurements obtained within 5 weeks of intervention were included. Results Correlations between initial ABF and fistulography measurement (ρ = 0.781), initial ABF and AngioFlow (ρ = 0.675), and final AngioFlow and ABF measurement (ρ = 0.798) were statistically significant. The correlation between final ABF and AngioFlow was significantly stronger than final ABF and fistulography (difference = 0.418, 95% bootstrap confidence interval [CI] [0.054, 0.914]). AngioFlow values and access survival after treatment did not show significant correlation. Conclusions AngioFlow measurements performed after treatment correlate more strongly with hemodialysis ABF values than fistulography measures. Further studies are needed to determine the target AngioFlow value obtained after treatment that is associated with the greatest survival benefit for access circuits.