Cumulative patency of contemporary fistulas versus grafts (2000-2010)

Abstract

Background and objectives: Comparisons of fistulas and grafts often overlook the high primary failure rate of fistulas. This study compared cumulative patency (time from access creation to permanent failure) of fistulas and grafts.

Design, setting, participants, & measurements: Vascular accesses of 1140 hemodialysis patients from two centers (Toronto and London, Ontario, Canada, 2000-2010) were analyzed. Cumulative patency was compared between groups using Kaplan-Meier survival curves and log-rank tests. Hazard ratios (HRs) for fistula failure relative to grafts and 95% confidence intervals (95% CIs) are reported.

Results: There were 1012 (88.8%) fistulas and 128 (11.2%) grafts. The primary failure rate was two times greater for fistulas than for grafts: 40% versus 19% (P<0.001). Cumulative patency did not differ between fistulas and grafts for the patients' first access (median, 7.4 versus 15.0 months, respectively [HR, 0.99; 95% CI, 0.79-1.23; P=0.85]) or for 600 with a subsequent access (7.0 versus 9.0 months [HR, 0.93; 95% CI, 0.77-1.13; P=0.39]). However, when primary failures were excluded, cumulative patency became significantly longer for fistulas than for grafts for both first and subsequent accesses (61.9 versus 23.8 months [HR, 0.56; 95% CI, 0.43-0.74; P<0.001] and 42.8 versus 15.9 months [HR, 0.56; 95% CI, 0.44-0.72; P<0.001]). Results were similar for forearm and upper-arm accesses. Compared with functioning fistulas, grafts necessitated twice as many angioplasties (1.4 versus 3.2/1000 days, respectively; P<0.001) and significantly more thrombolysis interventions (0.06 versus 0.98/1000 days; P<0.001) to maintain patency once matured and successfully used for dialysis.

Conclusions: Cumulative patency did not differ between fistulas and grafts; however, grafts necessitated more interventions to maintain functional patency.

Figure 1.

Survival curves of cumulative patency in hemodialysis patients. (A) 1140 patients: arteriovenous fistulas versus arteriovenous grafts (hazard ratio [HR], 0.99; 95% confidence interval [CI], 0.79–1.23). (B) 714 patients after excluding 426 primary failures: arteriovenous fistulas versus arteriovenous grafts (HR, 0.56; 95% CI, 0.43–0.74).

Figure 2.

Survival curves of cumulative patency in hemodialysis patients with forearm access. (A) 697 patients: arteriovenous fistulas versus arteriovenous grafts (hazard ratio [HR], 0.96; 95% confidence interval [CI], 0.74−1.24; P = 0.64). (B) 425 patients after excluding 272 primary failures: arteriovenous fistulas versus arteriovenous grafts (HR, 0.47; 95% CI, 0.34−0.66; P < 0.001).

Figure 3.

Survival curves of cumulative patency in hemodialysis patients with upper-arm access. (A) 443 patients: arteriovenous fistulas versus arteriovenous grafts (hazard ratio [HR], 1.22; 95% confidence interval [CI], 0.77−1.90; P = 0.37). (B) 289 patients after excluding 154 primary failures: arteriovenous fistulas versus arteriovenous grafts (HR, 0.94; 95% CI, 0.53−1.67; P=0.83).