The superior long-term patency of the left internal thoracic artery (ITA) graft is reflected in the enhanced survival of the patients who undergo the procedure, and its use has been shown to lead to a reduced need for reoperation. Evidence is accumulating that use of both ITAs at the primary operation further decreases the need for reoperation, and it is hoped that the use of other arterial conduits will augment this trend. Therefore, the popularity of bilateral ITAs and other arterial conduits in coronary artery operations is growing. However, many surgeons defer using both ITAs at the primary operation partly out of fear of the difficulties that may arise in conjunction with a possible future reoperation. Thirty-six patients underwent reoperation at The Cleveland Clinic Foundation 2 days to 13 years after an earlier bilateral ITA operation because of the progression of native disease, failure of the ITA or vein grafts, or the development of valve disease or end-stage ischemic heart disease. There were four early deaths (11%) and two late deaths, with an average follow-up of 4.3 years (range, 0 to 9.8 years). Forty-seven ITAs were patent preoperatively and 11 crossed the midline. Eleven were patent but stenosed and in need of revision or replacement. Two were damaged during reoperation; both were repaired, but one was ultimately replaced. Although the mortality associated with this procedure is relatively high and these operations are difficult, reoperation can be performed at an acceptable risk, and substantial surgical objectives can be achieved with good long-term results.(ABSTRACT TRUNCATED AT 250 WORDS)