Effect Of Long-Term Oral Anticoagulant Treatment On Mortality And Cardiovascular Morbidity After Myocardial-Infarction

The use of long-term oral anticoagulant treatment after myocardial infarction remains controversial because of conflicting findings on mortality in previous trials and the increased risk of bleeding associated with anticoagulants.We have carried out a randomised, placebo-controlled, double-blind, multicentre trial in 3404 hospital survivors of myocardial infarction. Eligible patients were randomly assigned to anticoagulant (nicoumalone or phenprocoumon) or placebo treatment within 6 weeks of discharge. The target prothrombin time was 2.8-4.8 international normalised ratio. During mean follow-up of 37 (range 6-76) months there were 170 deaths among 1700 anticoagulant-treated patients and 189 in 1704 placebo-treated patients (hazard ratio 0.90 [95% CI 0.73-1.11). Anticoagulant treatment led to significant reductions by comparison with placebo treatment in recurrent myocardial infarction (114 vs 242 patients; hazard ratio 0.47 [0.38-0.59]) and cerebrovascular events (37 vs 62; 0.60 [0.40-0.90]). Major bleeding complications were seen in 73 patients who received anticoagulants and 19 who received placebo.We conclude that long-term oral anticoagulant treatment after myocardial infarction in low-risk patients has a limited effect on mortality but achieves substantial benefit by reducing the risk of cerebrovascular events and recurrent myocardial infarction.