The effect of the angiotensin-converting-enzyme inhibitor zofenopril on mortality and morbidity after anterior myocardial infarction. The Survival of Myocardial Infarction Long-Term Evaluation (SMILE) Study Investigators.

BACKGROUND: Left ventricular dilatation and neuroendocrine activation are common after acute anterior myocardial infarction. Long-term treatment with an angiotensin-converting-enzyme (ACE) inhibitor may improve outcome by attenuating these processes. We investigated whether the ACE inhibitor zofenopril, administered for six weeks after anterior myocardial infarction, could improve both short-term and long-term outcome.

METHODS: A total of 1556 patients were enrolled within 24 hours after the onset of symptoms of acute anterior myocardial infarction, and they were randomly assigned in a double-blind fashion to receive either placebo (784 patients) or zofenopril (772 patients) for six weeks. At this time we assessed the incidence of death or severe congestive heart failure. The patients were reexamined after one year to assess survival.

RESULTS: The incidence of death or severe congestive heart failure at six weeks was significantly reduced in the zofenopril group (55 patients, 7.1 percent), as compared with the placebo group (83 patients, 10.6 percent); the cumulative reduction in the risk of death or severe congestive heart failure was 34 percent (95 percent confidence interval, 8 to 54 percent; P = 0.018). The reduction in risk was 46 percent (95 percent confidence interval, 11 to 71 percent; P = 0.018) for severe congestive heart failure and 25 percent (95 percent confidence interval, -11 to 60 percent; P = 0.19) for death. After one year of observation, the mortality rate was significantly lower in the zofenopril group (10.0 percent) than in the placebo group (14.1 percent); the reduction in risk was 29 percent (95 percent confidence interval, 6 to 51 percent; P = 0.011).

CONCLUSIONS: Treatment with zofenopril significantly improved both short-term and long-term outcome when this drug was started within 24 hours after the onset of acute anterior myocardial infarction and continued for six weeks.