Efficacy of oral anticoagulants compared with aspirin after infrainguinal bypass surgery (The Dutch Bypass Oral anticoagulants or Aspirin study): a randomised trial Original Research Article

Background Oral anticoagulants and aspirin are antithrombotic drugs that are commonly used in patients with vascular disease. We investigated whether either of these treatments prevented more effectively than the other bypass complications after infrainguinal bypass surgery. Methods We did a multicentre, randomised, open trial. 2690 patients who had undergone infrainguinal grafting were randomly assigned oral anticoagulants (target international normalised ratio 3·0–4·5, n = 1339) or aspirin (80 mg daily, n = 1351). We followed up patients for a mean of 21 months. The primary outcome was graft occlusion. Findings 308 graft occlusions occurred in the oral-anticoagulants group compared with 322 in the aspirin group (hazard ratio 0·95 [95% Cl 0·82–1·11]), which suggested no overall advantage for either treatment. Oral anticoagulants were beneficial in patients with vein grafts (0·69 [0·54–0·88]), whereas aspirin had better results for non-venous grafts (1·26 [1·03–1·55]). The composite outcome of vascular death, myocardial infarction, stroke, or amputation occurred 248 times in the oral-anticoagulants group and 275 times in the aspirin group (0·89 [0·75–1·06]). Patients treated with oral anticoagulants had more major bleeding episodes than those treated with aspirin (108 vs 56; 1·96 [1·42–2·71]).