Operation for two-vessel coronary artery disease: Midterm results of bilateral ITA grafting versus unilateral ITA and saphenous vein grafting - Discussion

Background. Several studies have demonstrated that single internal thoracic artery (ITA) grafting achieves better results than the use of vein grafts alone, but it is less clear whether bilateral ITA grafting produces better long-term results than a single ITA graft to the left descending coronary artery does. Methods. We analyzed the early and midterm results of the surgical treatment of two-vessel coronary artery disease (left anterior descending artery and right coronary artery) in two groups of 80 consecutive patients operated on between 1985 and 1989 who received either a bilateral ITA graft or a unilateral ITA graft combined with a saphenous vein graft. Patients were selected from a data base so as to be rigorously matched for demographic and clinical factors as well as angiographic variables, with the researcher being blinded to any additional intraoperative or postoperative data. Follow-up examination was performed after a mean postoperative interval of 8 years. Results. Univariate analysis showed a somewhat higher incidence of sternal complications in the bilateral ITA group (4.8% versus 1.2%; p < 0.02) and a significantly lower reintervention-free survival at 8 years in the group of patients who received a unilateral ITA and saphenous vein graft (84% ± 5.5% versus 95% ± 1.5%; p < 0.02). The latter was predominantly due to the development of significant main stem lesions necessitating a redo procedure during the follow-up interval or to the need for percutaneous coronary angioplasty of circumflex artery lesions that were not critical at the time of the initial operation. Perioperative risk was similar in both groups of patients. Old age and a history of congestive heart failure were the most important predictors of perioperative mortality and morbidity for patients receiving bilateral ITAs. Multivariate analysis did not demonstrate any benefit from bilateral arterial grafting over unilateral ITA bypass combined with saphenous vein grafting in terms of overall survival and event-free and intervention-free survival. Conclusions. Although bilateral ITA grafting can be performed with a perioperative risk comparable with that for unilateral ITA and saphenous vein grafting, long-term results (up to 8 years) of surgically treated two-vessel coronary artery disease are not improved by bilateral ITA grafting.