Two patients with total occlusion of the right internal carotid artery, were anesthetized for ACAB with remifentanil and thoracic epidural anesthesia. Case 1: A 71-year-old man with hypertension and diabetes mellitus underwent single-vessel ACAB under IV remifentanil analgesia, the dose of which was adjusted to 0.04-0.05 microg x kg(-1) x min(-1), along with an epidural infusion of 10 ml x hr(-1) of a mixture of 2% lidocaine and 2.5 microg x ml(-1) of fentanyl, the PaCO2 being maintained at 52-55 mmHg. When the patient felt pain, the remifentanil dose was elevated to 0.08 microg x kg(-1) x min(-1) and PaCO2 increased to 60 mmHg. Case 2: A 66-year-old man with rheumatoid arthritis underwent ACAB for two grafts. An intraaortic balloon pump (IABP) was inserted preoperatively. The anesthetic method used was the same as in case 1, except for an additional right femoral block to provide anesthesia for extraction of the saphenous vein. Remifentanil was infused at 0.05 microg x kg(-1) x min(-1) and PaCO2 maintained at 49-53 mmHg. In response to the patient's pain and movement, the remifentanil dose was increased to 0.07-0.10 microg x kg(-1) x min(-1) and PaCO2 to 60 mmHg.