THE INCIDENCE OF PERIOPERATIVE MYOCARDIAL-INFARCTION IN MEN UNDERGOING NONCARDIAC SURGERY

Objectives: To determine the incidence of and risk factors for perioperative myocardial infarction with noncardiac surgery and to test the accuracy of a risk stratification system. Design: Prospective cohort study. Setting: A large urban Veterans Affairs hospital. Participants: A total of 1487 men older than 40 years undergoing major, nonemergent, noncardiac operations. Measurements: Infarction was established by at least two of the following: development of new Q waves, typical change in creatine kinase MB, and positive technetium pyrophosphate scintigraphy. Patients were stratified preoperatively into high-, intermediate-, low-, and negligible-risk strata based on clinical markers corresponding to different levels of coronary artery disease prevalence. Main Results: Patients with coronary disease (high-risk stratum) had a 4.1 % incidence of infarction (13 of 319; 95% Cl, 1.8% to 6.4%); patients with peripheral vascular disease but no evidence of coronary disease (intermediate-risk stratum) had a 0.8% incidence (2 of 260, upper bound of Cl, 2.0%); patients with high atherogenic risk factor profiles but no clinical atherosclerosis (low-risk stratum) had a 0% incidence (0 of 256, upper bound of Cl, 1.2%). No cardiac deaths occurred in 652 men who had no atherosclerosis and low atherogenic risk factor profiles (the negligible-risk stratum). Factors independently associated with infarction included age more than 75 years (adjusted odds ratio, 4.77; Cl, 1.17 to 19.41), signs of heart failure on the preoperative examination (adjusted odds ratio, 3.31; Cl, 0.96 to 11.38), coronary disease (adjusted odds ratio, 10.39; Cl, 2.27 to 47.46), and a planned vascular operation (adjusted odds ratio, 3.72; Cl, 1.12 to 12.37). Conclusions: Coronary artery disease is the major risk factor for perioperative infarction. The stratification scheme identifies subsets of patients with different risks, and finer within-stratum distinctions can be made using additional variables.