Risks and benefits of performing coronary artery bypass grafting (CABG) within 30 days of an acute myocardial infarction (AMI) were examined. In 642 patients operated on between January 1988 and December 1993, emergent CABG was performed in 46 patients for cardiogenic shock mainly for failed thrombolysis in patients with an evolving AMI. The remaining patients underwent urgent (< 72 hours) or elective (> 72 hours) revascularization for failed percutaneous transluminal coronary angioplasty (n = 73), postinfarction angina (n = 381), vein graft stenosis (n = 100), and complications after an AMI (n = 42). In patients who underwent primary CABG for an uncomplicated AMI, the infarct was subendocardial in 68, anterolateral or septal in 200, inferior or posteroinferior in 200, and posterolateral in 32 patients. Early mortality (< 30 days) was 5.9% for the entire series and 0%, 4.5%, 4.5%, 29%, 9%, 8%, 10%, and 26% for the subsets of patients with subendocardial infarct, anterolateral or septal infarct, inferior or posteroinferior infarct, ischemic mitral regurgitation, left ventricular aneurysm, redo CABG, age more than 70 years, and left ventricular ejection fraction less than 0.30, respectively. By multivariate analysis, independent predictors of early mortality were left ventricular ejection fraction less than 0.30, age more than 70 years, and cardiogenic shock.(ABSTRACT TRUNCATED AT 250 WORDS)