Postoperative angiographic studies were carried out at 1 month, 1 year, and 10 years in two groups of patients: 238 patients with saphenous vein (SV) grafts and 40 patients with internal mammary artery (IMA) grafts. Cumulative patency was better in IMA grafts, both at 1 year (88.5% vs 76.4%) and at 10 years (84.1% vs 52.8%). Atheromatous changes in patent grafts at 10 years were frequent in SV grafts (29/66 or 43.9%) and uncommon in IMA grafts (1/19 or 5.2%; p less than .02). Attrition rate (11.8%) during the first year in IMA grafts (representing our initial experience with IMA grafts) was comparable to that of SV grafts (15.2%) in a group of patients operated on after 2 years of experience. Therefore, early attrition rate may be related to both experience and type of conduit. Later, at 10 years, the conduit itself appears to be the dominant factor. Furthermore, patients who received IMA grafts had a better survival rate at 10 years (84.3% vs 70%) than those who underwent SV bypass grafting.