Beneficial effect of prodromal angina pectoris is lost in elderly patients with acute myocardial infarction

Abstract

Background Prodromal angina pectoris occurring shortly before the onset of acute myocardial infarction is associated with a favorable outcome by the mechanism of ischemic preconditioning. Recent experiments have reported that the beneficial effect of ischemic preconditioning are reversed in the aged heart. Methods We studied 990 patients who underwent coronary angiography within 12 hours after the onset of acute myocardial infarction. Patients were divided into 2 groups: those aged <70 years (nonelderly patients, n = 722) and those aged ≥ 70 years (elderly patients, n = 268). Prodromal angina in the 24 hours before infarction was found in 190 of 722 nonelderly patients and in 66 of 268 elderly patients (26% vs 25%, P = .61). Results In nonelderly patients, prodromal angina was associated with lower peak creatine kinase levels (2438 ± 1939 IU/L vs 2837 ± 2341 IU/L, P = .04), lower in-hospital mortality rates (3.7% vs 8.8%, P = .02), and better 5-year survival rates ( P = .007). On the contrary, in elderly patients there was no significant difference in peak creatine kinase levels (2427 ± 2142 IU/L vs 2256 ± 1551 IU/L, P = .51), in-hospital mortality rate (21.2% vs 17.4%, P = .49), and 5-year survival rates ( P = .47). A multivariate analysis showed that prodromal angina in the 24 hours before infarction was associated with 5-year survival rate in nonelderly patients (odds ratio 0.49, P = .009) but not in elderly patients (odds ratio 1.12, P = .65). Conclusions In nonelderly patients, prodromal angina in the 24 hours before infarction was associated with a smaller infarct size and better short- and long-term survival, suggesting a relation to ischemic preconditioning. However, such a beneficial effect was not observed in elderly patients.