Detrimental effect of perioperative myocardial infarction on late survival after coronary artery bypass. Report from the Coronary Artery Surgery Study--CASS.

The influence of perioperative myocardial infarction on late survival after coronary artery bypass grafting was reviewed in 9,777 patients who underwent operation between 1974 and 1979. Definite or probable perioperative myocardial infarction was diagnosed in 561 patients (5.7%). The incidence decreased from 6.6% in 1974 to 4.1% in 1979 (p less than 0.005). Actuarial survival, including hospital deaths, at 1, 3, and 5 years was significantly greater in patients without infarction than in patients with infarction (96%, 94%, and 90% versus 78%, 74%, and 69%; p less than 0.0001). The difference persisted among patients dismissed from the hospital. Reduction in late survival among patients with perioperative infarction was due to the poor outcome of those who had complications (5 year survival rates 40% overall and 73% for patients dismissed from the hospital). Multivariate analysis identified perioperative myocardial infarction as an important independent predictor of late survival after bypass grafting; it was surpassed only by left ventricular function (wall motion score), age, and number of associated medical diseases.