CORONARY-BYPASS GRAFTING IN THE ELDERLY - SINGLE VERSUS BILATERAL INTERNAL MAMMARY ARTERY GRAFTS

A surgical experience between October 1983 and December 1990, with 1467 consecutive patients 65 years of age and over, was used to compare patients receiving single internal mammary artery grafts (n = 736) with those receiving bilateral internal mammary artery grafts (n = 731). The mean age in the single-graft group was 73.2 years and 70.9 years in the bilateral-graft group (p < 0.001). Various clinical parameters were analyzed that revealed that the single-graft group had more women and more patients with unstable angina, a history of previous myocardial infarction, and emergency surgery (p < 0.05). There was no significant difference in cigarette smoking, hypertension, diabetes mellitus, hyperlipidemia, triple vessel coronary artery disease, left main coronary artery stenosis, or left ventricular function between the two groups. Hospital mortality for the single-graft group was 6.4% (47 patients) and 3.1% (23 patients) for the bilateral-graft group (p < 0.004). No significant difference was observed between the groups in the rate of reoperation for bleeding, sternal infection, respiratory failure, stroke, or perioperative infarction. Follow-up was obtained in 663 hospital survivors (96.4%) in the single-graft group and in 691 (97.7%) in the bilateral-graft group. Mean follow-up in the single-graft group was 42.5 months (range, 1 to 92.4 months) and 43.0 months (range, 1 to 90.3 months) in the bilateral-graft group. In the single-graft group, survival was 60.7% +/- 4.8% (+/-standard error of the mean ) at 8 years (60 patients at risk); it was 67.9% +/- 8.1% (18 patients at risk) for the bilateral-graft group (p < 0.028). This comparative study demonstrates that bilateral internal mammary artery grafting can be accomplished in elderly patients with low operative risk and hospital morbidity. Moreover, patients in both groups had a reduction in cardiac events and significant functional improvement.