THERAPEUTIC APPROACHES TO POSTOPERATIVE ISCHEMIA

Previous attempts to Identify predictors of cardiac complications, an important cause of postoperative morbidity and mortality following non cardiac surgery, have focused mainly on the patient's preoperative sta te. Our research group, however, has found that adverse cardiac outcom e correlates most highly with the appearance of at least 1 ischemic ep isode determined by continuous ambulatory electrocardiographic monitor ing (AEM) in the early postoperative period. Such early postoperative ischemia conferred (1) a greater than 9-fold increased risk of experie ncing in-hospital cardiac death, nonfatal myocardial infarction, or po stoperative unstable angina, and (2) a greater than 2-fold increased l ong-term (2-year) risk of cardiac death, myocardial infarction, or ang ina requiring coronary angioplasty or coronary artery bypass grafting (CABG). Additionally, 5 predictors of such postoperative ischemia were identified: left ventricular hypertrophy, diabetes mellitus, hyperten sion, definite coronary artery disease, and preoperative digoxin use. These findings suggest that patients who are at high risk for postoper ative myocardial ischemia warrant more intensive postoperative monitor ing. Moreover, since such ischemia is potentially reversible, the test ing of strategies designed to prevent or manage postoperative ischemia appears warranted and is discussed. Our group also has established th e usefulness of AEM for identifying ischemic episodes in patients unde rgoing CABG. However, patients who require cardiopulmonary bypass pres ent unique problems regarding the interpretation of AEM recordings. We describe guidelines for the interpretation of AEM results obtained un der these conditions and suggest criteria based on the degree of inter pretability for patient inclusion in future studies.