Primary patency rates of AV fistulas and the effect of patient variables

DOQI (The Dialysis Outcomes Quality Initiative) recommend 40% of prevalent renal failure patients should be undergoing hemodialysis (HD) using autogenous arteriovenous fistulae (AVF). The aim of this study is to assess the primary patency rates of wrist and elbow fistulae, and to examine how patient variables influence the success of a fistula. In addition, an attempt has been made to address the main issue of survival rates in this high risk patient population.

A retrospective study was performed on all patients in the University Hospital of North Staffordshire who underwent creation of a wrist or elbow fistula for HD. During the study period 289 primary AVFs were created. In all, 210 AVF were sited at the wrist and 79 at the elbow. Follow-up ranged from 3 months to 4 yrs. Primary patency and patient death, transplant and transfer were taken as end points. Patient survival was defined as time of fistula creation to patient death. Actuarial survival was calculated using Kaplan-Meier survival analyses, with differences between groups determined using log rank analysis, and statistical significance obtained using X2 tests.

Primary patency for wrist fistulae was 49, 41 and 32% at 6, 12 and 24 months, respectively, and 57, 51 and 38% for elbow fistulae. Regression analysis showed fistula survival to be significantly greater in males than in females (p=0.023). Fistula survival rates in non-diabetics patients were higher than in patients with diabetes however, this was not significant (p=0.11); (54, 48 and 34% in diabetics compared to 45, 35 and 26% in non-diabetics at 6, 12 and 24 months, respectively). Age did not influence fistula survival; however, it did affect patient survival. Patient survival was 90, 74 and 56% at 1, 2 and 3 yrs, respectively, and in >60s fell to 86, 71 and 50%. Overall 74/245 (30%) patients died.

These results suggest that overall primary patency rates for wrist and elbow fistulae are comparable to similar studies at 6, 12 and 24 months. Fistula survival after this period is dictated by poor patient survival. Our findings suggest that creation of primary vascular access at the elbow in older females and diabetics may be associated with better results.