Arteriosclerotic histologic evaluation of the internal mammary artery in patients undergoing coronary artery bypass grafting

Abstract

During 1991, 52 patients undergoing myocardial revascularization had a biopsy of the distal internal left mammary artery (IMA) taken. There were 48 male and 4 female patients with a medium age of 58 years. Arteriosclerotic involvement of the IMA was assessed according to the scale of Kay. Using this index, grade 0 corresponds to a normal artery without atherosclerosis, grade 1 represents minimal disease, grade 2 a narrowing of less than 25% of the lumen, grade 3 narrowing between 25 and 50%, and grade 4 narrowing of 50% or greater of the lumen. Of the 52 IMA examined, the arteries with degree 0, 1, 2, 3, and 4 were: 19 (36.5%), 20 (38.4%), 9 (17.6%), 4 (7.6%) and zero. Thirty-three arteries (63.4%) had some degree of atherosclerosis. Considering the arteries with some atherosclerotic narrowing, 13 (25%) of the whole group had this pathological alteration. The IMA has a low but consistent incidence of arteriosclerosis involvement. Preoperative angiographic investigation of the IMA could be routinely performed.