Early coronary artery bypass grafting for complicated acute myocardial infarction

The occurrence of unstable angina or cardiogenic shock after an acute myocardial infarction characterizes a subgroup of patients with increased morbidity and mortality. To assess the efficacy of surgical revascularization in this cohort, 96 patients who underwent coronary artery bypass grafting within 6 weeks of an acute myocardial infarction were compared to 485 patients who underwent myocardial revascularization without recent infarction. Fourteen (15%) of the patients with acute infarction were in cardiogenic shock and 82 (85%) patients had unstable angina at the time of surgery. Preoperatively, the patients with acute infarction compared to the patients without acute infarction were older (+3.5 years), had an increased incidence of congestive heart failure (21% vs 13%), and had a lower mean ejection fraction (4% vs 65%). Preoperative intraaortic balloon support was used in 9 patients (65%) with cardiogenic shock, and in 16 patients (19%) with unstable angina. Mean interval to surgery from time of infarction was 14.9 days. Overall operative mortality was 7.3% (7 patients) for the acute infarction group 28% for patients with cardiogenic shock and 3.7% for patients with unstable angina compared to 3.7% for the group of patients without recent infarction. Earlier surgical intervention did not result in a significant increase in operative mortality. Discriminant analysis of the recent infarction cohort demonstrated that preoperative ejection fraction less than 45% and age greater than 70 were the most significant predictors of early mortality. Of the 89 patients surviving surgery, actuarial survival was 97% at 3 years with no late infarctions. At follow-up 95% of survivors were NYHA Class I or II.(ABSTRACT TRUNCATED AT 250 WORDS)