Body mass index and preinfarction angina in elderly patients with acute myocardial infarction

Background: Preinfarction angina, a clinical equivalent of ischemic preconditioning, seems to protect against in-hospital death, cardiogenic shock, and the combined endpoints in adult but not in elderly patients with acute myocardial infarction. Experimental evidence indicates that caloric restriction may restore ischemic preconditioning in aged animals. Objective: The objective was to verify whether body mass index (BMI) influences the cardioprotective effect of preinfarction angina in the elderly. Design: We retrospectively studied 820 patients aged greater than or equal to 65 y with acute myocardial infarction by evaluating BMI and major (death and cardiogenic shock) and minor in-hospital outcomes. Results: In-hospital death, cardiogenic shock, and the combined endpoints were not significantly different between elderly patients with and without preinfarction angina. Interestingly, in-hospital death, cardiogenic shock, and the combined endpoints were significantly fewer in elderly patients with than without preinfarction angina in the subset of patients with the lowest BMI (P < 0.01, < 0.01, and < 0.01, respectively). Regression analysis showed that preinfarction angina did not protect against in-hospital death when analyzed in all patients independently of BMI, whereas it was protective in the subset of patients with the lowest BMI (odds ratio: 0.06; 95% CI: 0.00, 0.54). Conclusions: Preinfarction angina does not protect against in-hospital death, cardiogenic shock, or the combined endpoints in elderly patients with acute myocardial infarction. With stratification by quartiles of BMI, the protective effect of preinfarction angina is preserved in elderly patients with the lowest BMI.