Early revascularisation and 1-year survival in 14-day survivors of acute myocardial infarction: a prospective cohort study.

BACKGROUND: Randomised trials of early revascularisation in acute coronary syndromes have yielded conflicting results with respect to effects on survival. We assessed the association between revascularisation within 14 days after the index event and 1-year mortality in individuals who survived for at least 14 days after an acute myocardial infarction.
METHODS: We studied a prospective cohort of patients admitted to the coronary care units of 61 Swedish hospitals between 1995 and 1998. We obtained 1-year mortality data from the Swedish National Cause of Death Register. We assessed 21,912 individuals with first registry-recorded acute myocardial infarction, who were younger than age 80 years, and alive at day 14. Relative risk of 1-year mortality in patients who had revascularisation (n=2554) or those who did not (n=19,358) within 14 days was calculated by Cox regression analysis, adjusting for multiple covariates that affect mortality and with a propensity score that adjusted for covariates that affected the likelihood of early revascularisation.
FINDINGS: At 1 year, unadjusted mortality was 9.0% (1751 deaths) in the conservative group and 3.3% (84 deaths) in the early revascularisation group. In the Cox regression analysis early revascularisation was associated with a reduction in 1-year mortality (relative risk 0.47; 95% CI 0.37-0.60; p<0.001). This relative reduction of mortality was similar in all subgroups irrespective of age, sex, baseline characteristics, previous disease manifestations, or treatment.
INTERPRETATION: Early revascularisation in individuals with acute myocardial infarction is associated with substantial reduction in 1-year mortality. Our findings lend support to the use of an invasive approach early after an acute myocardial infarction.