Perioperative myocardial infarction: late clinical course after coronary artery bypass surgery.

The effects of perioperative myocardial infarction (MI) on long-term survival and symptomatic status after coronary bypass surgery was assessed by a 64.9-month follow-up of the survivors (225) of all isolated coronary bypass surgery (227) performed at our institution from November 1975 to July 1976. Patients were separated into three groups: group 1 (111 patients) showed no postoperative ECG changes; group 2 (31 patients) showed appearance and persistence of new or enlarged Q waves with localized ST elevation; and group 3 (83 patients) showed less specific ECG changes. Group 2 had greater technetium pyrophosphate scan positivity (eight of 19 vs one of 35, p < 0.0005) and higher peak MB-CK activity (83 20 vs 20 + 3 IU/I (mean + SEM) (p < 0.01) than group 1. Using the ECG criteria of group 2, the incidence of perioperative MI was 13.7% (31 of 227 patients). Groups 1 and 2, compared according to age, prior infarction, number of diseased vessels, left main stenosis, coronary collaterals, left ventricular ejection fraction and number of grafts inserted, were not significantly different. However, both ischemic (aortic cross-clamp) time and total pump time were greater in group 2 than in group 1 (65 + 3 vs 51 2 minutes and 166 + 7 vs 132 ± 3 minutes, respectively, p < 0.05). There were no perioperative (30-day) deaths in group 1, whereas group 2 had a perioperative mortality rate of 3.2% (one of 31). The 5-year survival rates ofgroup 1 (94.3%), group 2 (96.8%) and group 3 (91.1 %) were not significantly different. Late postoperative status regarding relief of angina, dyspnea, level of physical activity, and use of cardiac medications were not different between the groups. In all patients and in those age 55 years or younger, work status was not different. Although perioperative MI may be associated with a higher operative mortality, late survival and cardiac status were not affected by it in 5 years of follow-up.