THE EFFECT OF WARFARIN ON MORTALITY AND REINFARCTION AFTER MYOCARDIAL-INFARCTION

Background and Methods. The use of oral anticoagulation in the long-term treatment of survivors of acute myocardial infarction has been highly controversial. We therefore randomly assigned 1214 patients who had recovered from acute myocardial infarction (mean interval from the onset of symptoms to randomization, 27 days) to treatment with warfarin (607 patients) or placebo (607 patients) for an average of 37 months (range, 24 to 63). Results. At the end of the treatment period, there had been 123 deaths in the placebo group and 94 in the warfarin group — a reduction in risk of 24 percent (95 percent confidence interval, 4 to 44 percent; P = 0.027). A total of 124 patients in the placebo group had reinfarctions, as compared with 82 in the warfarin group — a reduction of 34 percent (95 percent confidence interval, 19 to 54 percent; P = 0.0007). Furthermore, we observed a reduction of 55 percent (95 percent confidence interval, 30 to 77 percent) in the number of total cerebrovascular accidents in the warfarin group as compared with the placebo group (44 vs. 20; P = 0.0015). Serious bleeding was noted in 0.6 percent of the warfarin-treated patients per year. Conclusions. Long-term therapy with warfarin has an important beneficial effect after myocardial infarction and can be recommended in the treatment of patients who survive the acute phase. (N Engl J Med 1990; 323: 147–52.) © 1990, Massachusetts Medical Society. All rights reserved.