In an attempt to make evaluation of coronary artery bypass more meaningful, operative coronary arteriography has been used to aid in defining more precisely the technical aspects of the operation at a time when corrective measures can be carried out. Arteriography is performed following the completion of distal bypass graft anastomoses, whether saphenous vein or internal mammary artery (IMA) bypasses are used. Cut films are exposed at the rate of 2 to 4 frames per second and are evaluated for showing (1) status of anastomosis, (2) status of runoff, (3) lesions undetected preoperatively, and (4) any problems with the bypass conduit. A total of 934 vessels (including 107 IMA grafts) have been visualized in 535 patients. Some form of technical revision was necessary in nine instances. The use of this technique during intraoperative balloon dilatation, in conjunction with and to extend the benefits of conventional bypass, is currently being evaluated.