Timing of coronary artery bypass grafting after acute myocardial infarction.

Appropriate timing for coronary artery bypass grafting (CABG) after acute myocardial infarction (AMI) remains controversial. We retrospectively examined 423 patients who underwent CABG within 21 days of an AMI between 1992 and 1995, mainly for postinfarction angina and complex anatomy. The operative mortality rates associated with increasing time intervals between AMI and CABG were 17.4, 9.1, 4.0, and 5.8 per cent, for less than 6 hours, 6 to 24 hours, 1 to 7 days, and 7 to 21 days, respectively. There were 25 (5.9%) deaths overall. Statistical analysis was performed to evaluate the following preoperative parameters: age, sex, reoperation, previous myocardial infarction (MI), MI type and location, anatomy, cardiogenic shock, unstable angina, ventricular arrhythmias, extending MI, ejection fraction, indications for surgery, cardiac index, and interval from infarction to CABG. Interval between operation and AMI did not have a significant impact on patient outcome. Factors associated with an increased hospital mortality were ejection fraction < 30 per cent, age > 70 years, presence of cardiogenic shock, and cardiac index < 1.5. Only cardiac index proved to be a significant predictor of mortality (P < 0.001). We conclude that the timing of CABG, in and of itself, has no significant effect on hospital mortality of symptomatic patients within 3 weeks of AMI.