Objectives: This study sought to assess the independent contribution of nonfatal reinfarction to the risk of subsequent death in patients with acute myocardial infarction undergoing thrombolytic therapy.
Background: A composite of "unsatisfactory outcomes" as an end point has increased statistical power and facilitated evaluation of evolving treatment regimens in acute myocardial infarction. The significance of nonfatal reinfarction as a component of a composite end point has not been evaluated in the thrombolytic era.
Methods: Event rate of nonfatal reinfarction over 3-year follow-up was evaluated in patients with acute myocardial infarction entered into the Thrombolysis in Myocardial Infarction Phase II trial. The independent risk of nonfatal reinfarction for subsequent death within various time intervals of follow-up was determined. The mortality rate after nonfatal reinfarction was compared with that of a matched control group.
Results: During 3-year follow-up, 349 of 3,339 patients had a nonfatal reinfarction. Univariate predictors were history (antedating the index event) of angina (p = 0.01), hypertension (p = 0.01), multivessel disease (p = 0.007) and not a current smoker (p = 0.003); the latter was an independent predictor (relative risk [RR] 1.3, 99% confidence interval [CI] 1.0 to 1.8). Forty-three of the 349 patients with a nonfatal reinfarction died: RR for death (vs. patients without a nonfatal reinfarction) was 1.9 (99% CI 1.1 to 3.2) if reinfarction occurred within 42 days of study entry, 6.2 (99% CI 3.0 to 12.9) if reinfarction occurred between 43 and 365 days and 2.9 (99% CI 0.6 to 13.4) if reinfarction occurred between 366 days and 3 years. The cumulative 3-year death rate was 14.1% in patients with a nonfatal reinfarction compared with 7.9% (p < 0.01) in a matched control group. Univariate predictors of death after nonfatal reinfarction were age > or = 65 years (p < 0.001), not low risk category (p = 0.015) and history of heart failure before the index event (p < 0.001). Age > or = 65 years was the only independent predictor (RR 5.4, 99% CI 2.3 to 12.4).
Conclusions: Nonfatal reinfarction is a strong and independent predictor for subsequent death. It represents a powerful component for a composite end point in patients who received thrombolytic therapy after acute myocardial infarction.