Heparin Bonding Does Not Improve Patency of Polytetrafluoroethylene Arteriovenous Grafts

Background: Heparin-bonded polytetrafluoroethylene (PTFE) grafts (hepPTFE) were developed to decrease rates of graft thrombosis. Our objective was to compare the patency of arteriovenous grafts (AVGs) for dialysis access with and without heparin bonding in a tertiary care setting. Methods: Records of patients who had an AVG placed between January 2008 and June 2011 were retrospectively reviewed. Outcome measures were primary, assisted primary, and secondary patency. Marginal survival models (to account for correlation of accesses within subjects) using Cox proportional hazard regression were used for statistical comparisons. Results: A total of 223 patients had 265 grafts placed. Of these, 62 (23%) were hepPTFE grafts. The average age was 66 +/- 15 years in the hepPTFE group and 59 +/- 17 years in the noneheparin-bonded control group (PTFE; P < 0.01). Of the hepPTFE group, 39% were men, 81% were African American, 63% were diabetic, and 81% had a tunneled catheter at the time of access placement. Of the PTFE group, 35% were men, 85% were African American, 56% were diabetic, and 83% had a tunneled catheter. HepPTFE grafts failed to improve rates of primary, assisted primary, or secondary patency based on univariate analysis (hazard ratio [HR]: 1.37 [95% confidence interval {CI}: 0.99-1.88]; HR: 1.39 [95% CI: 0.98-1.96]; and HR: 1.20 [95% CI: 0.73-1.96], respectively). The number of secondary interventions was similar in the 2 groups (1.1 interventions per person-year of follow-up PTFE versus 1.4 hepPTFE; P = 0.13). A multivariable model including age, diabetes, peripheral artery disease, tobacco use, previous access placement, and tunneled catheter found that the HR for hepPTFE was not significantly different than PTFE in primary, assisted primary, or secondary patency (HR: 1.32 [95% CI: 0.91-1.90]; HR: 1.35 [95% CI: 0.91-1.99]; and HR: 1.15 [95% CI: 0.62-2.16], respectively). Conclusions: hepPTFE AVGs failed to improve patency or decrease secondary interventions compared to standard PTFE grafts. Prospective studies are needed to confirm these results.