Atherosclerosis in internal mammary and related arteries.

The incidence of atherosclerosis in internal mammary, subclavian, carotid and coronary arteries was studied in an autopsy series of 153 patients, and the structure of the internal elastic lamina was compared in internal mammary and radial arteries. Atherosclerotic changes were exceptional in internal mammary artery, whereas only 12-30% of the other arteries were macroscopically normal. The internal elastic lamina of internal mammary artery was found to be significantly less fragmented than that of radial artery, which may partly explain both the lower incidence of atherosclerosis in internal mammary artery and failure of radial artery grafts. As six (3.9%) of the 153 patients had total or almost total subclavian artery occlusion, subclavian angiography is recommended for patients who are candidates for coronary bypass grafting with internal mammary artery.