Left main coronary artery stenosis: factors predicting cardiac events in patients awaiting coronary surgery

Although most patients with left main coronary artery stenosis undergo urgent coronary artery bypass grafting, limited information is available regarding the risk factors that might lead to cardiac events between angiographic diagnosis and surgery. We retrospectively reviewed 1,731 cases of coronary artery bypass grafting at our institution, 97 of which were performed in patients with significant (> or = 50%) left main coronary artery stenosis. These patients were placed in 1 of 2 groups: eventful waiting or uneventful waiting. We analyzed multiple preoperative variables, and the incidence of serious cardiac events (death, myocardial infarction, unstable angina, left ventricular failure, and life-threatening ventricular arrhythmias) during the waiting period between angiography and surgery Four patients (4.1%) experienced serious cardiac events while awaiting surgery (1 had non-ST-elevation myocardial infarction; 3 had life-threatening ventricular arrhythmias); none died. All the events occurred more than 24 hours after cardiac catheterization. Of the preoperative variables analyzed (acute coronary syndrome, age, history of diabetes, hypertension, hyperlipidemia, smoking, renal failure, severity of left main stenosis, right coronary artery involvement, ejection fraction, and use of intra-aortic balloon pump), only acute coronary syndrome predicted the incidence of preoperative cardiac events (P=0.001). The occurrence of severe cardiac events while patients await coronary artery bypass grafting is rare. Carefully selected patients with severe left main coronary artery stenosis can safely await surgery. Concomitant acute coronary syndrome and severe left main coronary artery stenosis indicate a high risk for cardiac events. Therefore, in patients with these conditions, emergency coronary artery bypass may be preferable.