Does mammary artery grafting increase surgical risk?

From 1980 through 1982, 7105 patients underwent primary isolated myocardial revascularization. Of these, 49.2% received only vein grafts and 50.2% received at least one internal mammary artery graft. The incidence of mammary artery grafting increased from 33.5% in 1980 to 67.1% in 1982. The operative mortality rate was 1.4% in the vein group and 0.2% in the mammary artery group (p less than .0001). A multivariate analysis identified six incremental risk factors for operative mortality. After adjusting for these risk factors, the use of vein grafts only was found to be an incremental risk factor (p less than .0001). In a subset of patients without major risk factors, there was no difference in the incidence of perioperative infarction, respiratory insufficiency, wound complication, stroke, use of intra-aortic balloon, reoperation for bleeding, or blood requirements. We conclude that internal mammary artery grafting is safe and is not associated with increased surgical morbidity or mortality.