A Meta-analysis of Preoperative Duplex Ultrasound Vessel Diameters for Successful Radiocephalic Fistula Placement

Abstract

Background The Kidney Dialysis Outcomes Quality Initiative (K/DOQI) guidelines for vascular access recommend the use of radiocephalic wrist arteriovenous fistulas (RCAVFs) as the initial option for dialysis access. The survival rate of a successfully placed fistula is excellent. However, 10–24% of RCAVFs fail to reach functional status as the result of early thrombosis or maturation failure. Many authors have investigated the utility of preoperative vascular mapping by Duplex ultrasound to predict adequate vessel size for successful fistula placement. This meta-analysis is the first in which preoperative radial arterial (RAD) and cephalic venous diameters (CVD) required for favorable fistula outcomes are reviewed. Methods A literature search was performed by use of the MEDLINE electronic base for “arteriovenous, fistula, ultrasound, and hemodialysis.” The analysis yielded 166 studies, of which 20 studies included preoperative duplex data. Meta-analysis was performed by applying the statistical test of comparing two proportions, assuming equal variances. Results A total of 433 patients were duplexed for preoperative evaluation of the RAD and 386 for CVD. The total number of subjects ranged from 21 to 91, mean age 58.7 years. The subjects were 55.5% male, 39.0% with diabetes mellitus. Meta-analysis yielded 2.0 mm for RAD and 2.0 mm for CVD as designated cutoff vessel diameters. Our study showed the mean fistula success rate was significantly different between RAD >2.0 mm (59%) and RAD >2.0 mm (40%). The mean fistula success rate was also significantly different between CVD > 2.0 mm (71%) and >2.0 mm (29%). Successful fistula placement was defined as a functional fistula at least 4–6 weeks after creation. Conclusion On the basis of our study, the use of Duplex ultrasound is important in determining preoperative vessel diameter size, and subsequent functional success rate of fistula placement.