Effect of low dose aspirin and dipyridamole on primary patency of arteriovenous grafts in hemodialysis patients: a randomized double-blind placebo-controlled trial

Background There is some evidence for the efficacy of antiplatelet therapies in increasing the vascular access patency duration or decreasing the thrombosis of arteriovenous grafts. Objective To determine the effect of low dose aspirin and dipyridamole on primary patency of arteriovenous grafts in hemodialysis patients. Methods This randomized, double-blind, placebo-controlled trial was done at Imam Reza Hospital in Mashhad, Iran from September 10, 2015 to July 05, 2016. Sixty hemodialysis patients, after the placement of a new arteriovenous graft, were divided into three study groups which including; Group 1, who received 80 mg aspirin tablet daily, Group 2 received 80 mg aspirin plus 75 mg dipyridamole daily and Group 3 received placebo daily. Primary unassisted patency was recorded in follow-up until 12 months and the outcomes were analysed using one-way ANOVA test. Results Primary patency time in Group 1 (Aspirin) was 324.75±147.00 day and for Group 2 (Aspirin + Dipyridamole) was 399.05±92.09 day and for Group 3 (Placebo) was 383.55±108.23 day. There were no significant differences between the 3 groups (p>0.05). Successful dialysis was done in 16.7% in Group 1, 37.5% in Group 2 and 45% in Group 3 from brachial arteriovenous grafts after 1-year follow-up (p=0.746). Conclusions In treating dialysis patients, treatment with low dose aspirin and dipyridamole is not effective on increasing the synthetic grafts primary patency duration. Trial registration The trial was registered at the Thai Clinical Trials Registry (http://www.clinicaltrials.in.th) with the Trct id: TCTR20160920003. Funding The authors received no financial support for the research, authorship, and/or publication of this article.