Perioperative risk of bilateral internal mammary artery grafting: analysis of 500 cases from 1971 to 1984.

The records of the first 500 patients (420 men, 80 women, mean age 55 years, range 24 to 78) undergoing bilateral internal mammary artery (IMA) grafting were reviewed to determine in-hospital morbidity and mortality. Sixty patients (12%) had had previous cardiac operations and 130 (26%) previous saphenous vein removal. From two to seven total grafts (mean 3.2) were performed, including 595 IMA grafts to the anterior descending or diagonal artery, 355 to the circumflex, and 105 to the right coronary system. To assess changing risks, the first 125 patients (group A, 1971 to 1982) were compared with the next 375 (group B, 1982 to 1984). Major complications in groups A and B included stroke, four (3.2%) vs ine (2.4%); wound complications requiring reoperation, three (2.4%) vs five (1.3%); prolonged (greater than 48 hr) respiratory care, seven (5.6%) vs 19 (5.1%); and death, two (1.6%) vs five (1.3%) (no p value less than .05). Complications significantly less frequent in group B were new Q waves in nine (7.2%) vs 10 (2.7%) in group A (p = .02) and reoperation for bleeding in 17 (13.6%) vs 16 (4.3%) in group A (p = .0003). Logistic regression analysis showed that major complications did not correlate with gender, diabetes, number of grafts, or preoperative left ventricular function but were associated with increasing age (p = .0001) and previous cardiac surgery (p = .009) and were decreased by the use of cardioplegia (p = .002). The excellent long-term patency of IMA grafts, combined with low and decreasing perioperative risk, supports the continued use of bilateral IMA grafting.