COMPARISON OF HIGH-DOSE WITH LOW-DOSE ASPIRIN IN PATIENTS WITH MECHANICAL HEART-VALVE REPLACEMENT TREATED WITH ORAL ANTICOAGULANT

Background There are no reported studies on the safety and efficacy of low-dose aspirin with low-intensity oral anticoagulation in patients with heart valve replacement. In this study, we compared the use of 10 0 mg/d aspirin with 650 mg/d aspirin in the prevention of systemic emb olism and vascular death in pa tients with heart valve replacement who were being treated with oral anticoagulants with a target internation al normalized ratio (INR) of 2.0 to 3.0. Methods and Results Four hund red nine of 416 consecutive patients who had cardiac valve replacement were randomized in open allocation into one of two groups; both group s were treated with oral anticoagulant therapy with a target WR of 2.0 to 3.0. Two hundred seven patients who received 100 mg/d aspirin for an average of 24.1 months were compared with 202 patients who received 650 mg/d aspirin for an average of 21.7 months in a randomized-treatm ent, open-allocation study. There were no significant differences in s ystemic embolism, vascular death, or total death rates between the low - and high-dose aspirin treatment groups (0.5 and 1.1, 1.2 and 0.5, an d 4.6 and 2.5 per 100 patients/y, respectively). The total number of h emorrhagic events was 13.4 per 100 patients/y in the high-dose aspirin group and 7.9 per 100 patients/y in the low-dose aspirin group (P=.03 5), but the rate of bleeding was influenced by dipyridamole in the 650 -mg aspirin group. Conclusions In patients with mechanical heart valve replacements, low-dose aspirin (100 mg/d) in conjunction with oral an ticoagulants at an INR of 2.0 to 3.0 is as effective as the use of hig h-dose aspirin (650 mg/d) in the prevention of systemic embolism.