Early postinfarction ischemia: Clinical, angiographic, and prognostic significance

Abstract

Early ischemia, defined as angina with transient ST-T changes during hospitalization, 24 hr or more after an acute myocardial infarction (MI), was observed in 79 (18%) of a consecutive series of 449 patients surviving an MI and catheterized a mean of 10 ± 3 days after admission. Three clinical factors present 24 hr after admission could identify patients at low, medium, and high risk of subsequent ischemia: the 32 patients with a non-Q wave MI, previous angina, and two or more risk factors had a risk greater than 50% and the 118 patients with Q wave MI, no previous angina, and absence of risk factors had a risk of less than 8%. The angiographic correlates of early ischemia were number of vessels with 70% or more stenosis (2.1 ± 0.8 vs 1.7 ± 0.8/patient, p < .0001), number of diseased coronary artery segments (2.8 ± 1.4 vs 2.1 ± 1.2, p < .0002), collateral circulation at jeopardy (24% vs 15% of patients, p < .005), and fewer collateral vessels distal to a tight stenosis (59 vs 72% of patients, p = .04). The stepwise logistic regression retained one angiographic and two clinical independent predictors of early ischemia: number of diseased vessels (p = .0008), presence of a non-Q wave MI (p = .0027), and previous angina (p = .017). Extension of the infarction during hospitalization was diagnosed in 31 patients (7% of the total population) and could be independently predicted only by the presence of early ischemia: it occurred in 22 of the 79 patients with ischemia (28%) vs nine of 370 without (2.4%, p < .0001). During a mean follow-up of 14 ± 8 months (2 to 28), cumulative survival was 83% in patients with early ischemia and 92% in those without (p = .01); survival without MI was 67% vs 81%, respectively. Thus, early ischemia after MI is a frequent finding that is clinically predictable. It is associated with more severe coronary artery disease and identifies, independently of non-Q wave MI and of extent of coronary artery disease, a group at high risk for MI extension in hospital and for cardiac events during follow-up.