Clinical review: how to identify high-risk surgical patients.

Postoperative outcome is mainly influenced by ventricular function. Tests designed to identify myocardial ischemia alone will fail to detect cardiac failure and are thus inadequate as a screening test for identification of cardiac risk in noncardiac surgical patients. We find that the degree of cardiac failure is the most important predictor of morbidity and mortality. We use cardiopulmonary exercise testing to establish the anaerobic threshold as the sole measure of cardiopulmonary function as well as to detect myocardial ischemia. Patients with an anaerobic threshold < 11 ml/min/kg are at risk for major surgery, and perioperative management must be planned accordingly. Myocardial ischemia combined with moderate to severe cardiac failure (anaerobic threshold < 11 ml/min/kg) is predictive of the highest morbidity and mortality.