Effect of Dipyridamole plus Aspirin on Hemodialysis Graft Patency

Abstract

BACKGROUND Arteriovenous graft stenosis leading to thrombosis is a major cause of complications in patients undergoing hemodialysis. Procedural interventions may restore patency but are costly. Although there is no proven pharmacologic therapy, dipyridamole may be promising because of its known vascular antiproliferative activity. METHODS We conducted a randomized, double-blind, placebo-controlled trial of extended-release dipyridamole, at a dose of 200 mg, and aspirin, at a dose of 25 mg, given twice daily after the placement of a new arteriovenous graft until the primary outcome, loss of primary unassisted patency (i.e., patency without thrombosis or requirement for intervention), was reached. Secondary outcomes were cumulative graft failure and death. Primary and secondary outcomes were analyzed with the use of a Cox proportional-hazards regression with adjustment for prespecified covariates. RESULTS At 13 centers in the United States, 649 patients were randomly assigned to receive dipyridamole plus aspirin (321 patients) or placebo (328 patients) over a period of 4.5 years, with 6 additional months of follow-up. The incidence of primary unassisted patency at 1 year was 23% (95% confidence interval [CI], 18 to 28) in the placebo group and 28% (95% CI, 23 to 34) in the dipyridamole–aspirin group, an absolute difference of 5 percentage points. Treatment with dipyridamole plus aspirin significantly prolonged the duration of primary unassisted patency (hazard ratio, 0.82; 95% CI, 0.68 to 0.98; P = 0.03) and inhibited stenosis. The incidences of cumulative graft failure, death, the composite of graft failure or death, and serious adverse events (including bleeding) did not differ significantly between study groups. CONCLUSIONS Treatment with dipyridamole plus aspirin had a significant but modest effect in reducing the risk of stenosis and improving the duration of primary unassisted patency of newly created grafts. (ClinicalTrials.gov number, NCT00067119.)

Thrombophilia and Arteriovenous Fistula Survival in ESRD

“…These patients with hypercoagulable states or combined thrombophilia should be preoperatively identified to tailor antithrombotic therapy and intensify surveillance, especially during the first, most vulnerable months after surgery. However, the optimal prophylaxis for access thrombosis and stenosis is not settled despite extensive efforts (29)(30)(31)(32)(33)(34)(35).…”

Vascular access today

“…The risk for thrombosis increases with decreasing blood flow [75] . Treatment with dipyridamole plus aspirin has a significant but modest effect in reducing the risk of stenosis and improving the duration of primary unassisted patency of newly created grafts [76] . Dixon et al [77] support that use of aspirin is associated with a trend toward longer primary unassisted patency of newly placed HD grafts, similar to that observed for extended-release dipyridamole plus lowdose aspirin (ERDP/ASA).…”

Economic analysis of angiography and preemptive angioplasty to prevent hemodialysis‐access thrombosis

“…Instead, we focused on the economic impact of an aggressive angiography program to prevent access thrombosis, a measurable and desirable outcome evaluated in multiple reports [6][7][8][9][10][11][12]24]. We also determined whether thrombosis rates would translate into some measurable difference in access site attrition and observed similar rates of access loss requiring the use of tunneled catheters or surgical revision between the baseline and screening periods (5.7% vs. 5.7% per 100 patient-yrs).…”