Angiotensin receptor blockers and antiplatelet agents are associated with improved primary patency after arteriovenous hemodialysis access placement.

OBJECTIVE: Dialysis access failure is a major cause of morbidity, mortality, and cost in end-stage renal disease. We undertook a study to determine the influence of medication use on dialysis access failure.
METHODS: After institutional review board approval, we performed a retrospective analysis of all upper extremity hemodialysis accesses placed from 2005 to 2009 at the Washington DC Veterans Affairs Medical Center. For each access, the date of failure was recorded. For patients who died or were lost to follow-up, the date of the last documented functional patency (censoring) was recorded. The primary exposures were 12 medication classes. Patient demographics, behaviors, comorbidities, and access characteristics were used as covariates. Patency rates were calculated using Kaplan-Meier methods. Cox proportional hazard models controlling for patient characteristics and all medication classes, with procedures clustered within patients, were used to determine the influence of medication class on primary patency.
RESULTS: Two hundred sixty autogenous and 126 prosthetic newly placed accesses were identified. Of these, three lower extremity accesses and six accesses with unknown thrombosis date were excluded. Forty-five (18%) of the remaining 257 autogenous accesses were excluded for primary nonfunctionality (patent, but with inadequate venous dilatation for initial hemodialysis), because the primary outcome was long-term functional patency. The remaining 212 autogenous and 120 prosthetic accesses were analyzed. Primary patency rates at 1 and 2 years were 55.2% and 49.1% for autogenous accesses, and 50.2% and 29.7% for prosthetic accesses, respectively. On multivariable analysis, angiotensin receptor blockers (ARBs) were associated with reduced hazard of both autogenous (hazard ratio [HR], 0.35; 95% confidence interval [CI], 0.16-0.76; P = .008) and prosthetic (HR, 0.41; 95% CI, 0.18-0.95;P = .039) access failure. On subgroup analysis, ARBs prolonged autogenous access primary patency among patients receiving antiplatelet medication (aspirin, clopidogrel; HR, 0.16; 95% CI, 0.05-0.52;P = .002) but had no demonstrable benefit among patients not receiving antiplatelets (HR, 1.35; 95% CI, 0.34-5.31;P = .670). There were no significant drug-drug interactions in the analysis of prosthetic accesses. Weighted regression models demonstrated low multicollinearity among the model variables.
CONCLUSION: Our data suggest that therapy with an ARB plus antiplatelet agent is associated with prolonged autogenous access primary patency, and therapy with an ARB with or without antiplatelet agents is associated with prolonged prosthetic access primary patency. Randomized studies are needed to confirm the causal role of ARBs and to determine the optimal therapeutic regimen (dose, timing, and duration) to promote access patency. Published by Mosby, Inc.