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

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Abstract
The effects of perioperative myocardial infarction (MI) on long-term survival and symptomatic status after coronary bypass surgery were assessed by a 64.9-mo. follow-up of the survivors (225) of isolated coronary bypass surgery (227). Patients were separated into 3 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 (8 of 19 vs 1 of 35, P < 0.0005) and higher peak MB-CK creatine kinase activity (83 .+-. 20 vs. 20 .+-. 3 IU/l) (mean .+-. SEM [standard error of the mean]) (P < 0.01) than group 1. From 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 collaterrals, left ventricular ejection fraction and number of grafts inserted, were not significantly different. Both ischemic (aortic cross-clamp) time and total pump time were greater in group 2 than in group 1 (65 .+-. 3 vs 51 .+-. 2 min and 166 .+-. 7 vs 132 .+-. 3 min, 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% (1 of 31). The 5-yr survival rates of group 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 .ltoreq. 55 yr, 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 yr of follow-up.