Bypass surgery for left main coronary artery disease. Reduced perioperative myocardial infarction with preoperative intra-aortic balloon counterpulsation.

From July 1975 to December 1977, 91 consecutive patients with left main coronary artery disease defined by cardiac catheterisation as greater than or equal to 50 per cent luminal narrowing underwent coronary bypass surgery. Prospective examination of the preoperative and postoperative clinical course of these patients was performed to determine the incidence of perioperative myocardial infarction. Intra-aortic balloon counterpulsation was instituted preoperatively in 35 patients, and these patients were classed as group A. Fifty-six patients did not receive the intra-aortic balloon pump and were classed as group B. Of 26 demographic, clinical, haemodynamic, and operative descriptors, only two were found to be significantly different between the two groups: the severity and the pattern of angina. Group A had a higher percentage of patients with class IV angina (80% vs 45%) and a greater proportion with unstable angina (37% vs 7%). Despite these differences group A patients had only a 3 per cent incidence of perioperative myocardial infraction while group B had a 23 per cent perioperative infarction rate. It is suggested that perioperative intra-aortic balloon counterpulsation can reduce the risk of perioperative myocardial infraction in patients with left main coronary artery stenosis.