Can primary failure of arteriovenous fistulas be anticipated?

Abstract

Primary failure, early thrombosis, and inadequate maturation are the main complications encountered in arteriovenous fistulas. Doppler ultrasonographic assessment of flow-mediated dilatation (FMD) is currently used for the early diagnosis of atherosclerosis. Clinical experience in the use of FMD for preoperative assessment of vasculature is rather limited; therefore, we sought to elucidate the relationship between preoperative FMD and primary failure of the fistula. Thirty-three patients with end-stage renal disease who were admitted to our hospital between January and July 2005 were included in our study. Medical histories were established and the internal diameter, wall thickness, peak systolic flow rate, and resistive index (RI) were measured in the cephalic vein and radial and brachial arteries. Flow-mediated dilatation and nitrate-mediated dilatation (NMD) of the brachial artery were assessed. Fistulas were evaluated 48 hours and 30 days postoperatively. Brachial arterial internal diameter was lower in all fistulas that developed primary failure in 48 hours (0.4 ± 0.07 cm vs. 0.35 ± 0.07 cm, P = 0.016). The radial artery RI was found to be significantly elevated in fistulas with both early (48-hour) and late-term (30-day) failure (0.9 ± 0.08 vs. 0.68 ± 0.3, P = 0.01, and 0.86 ± 0.8 vs. 0.67 ± 0.3, P = 0.038, respectively). The brachial artery peak systolic flow rate was significantly reduced in patients in the radiocephalic fistula group that developed early and late-term failure (42.9 ± 12 cm/sec vs. 68.4 ± 10 cm/sec, P = 0.01, and 44.1 ± 13 cm/sec vs. 57.7 ± 16 cm/sec, P = 0.038, respectively). Our study, constrained by a smaller, older patient group, was unable to show a statistically significant correlation between FMD, NMD, and fistula success. Any single parameter may not be sufficient to assess vascular health preoperatively. A multifactorial approach incorporating parameters evaluating arterial and venous function might be more effective in predicting fistula success. Further studies on larger patient groups may indeed demonstrate the value of these assessments.

Keywords: Arteriovenous fistula; endothelial dysfunction; flow-mediated dilation; hemodialysis; primary failure.