Does location of the second internal thoracic artery graft influence outcome of coronary artery bypass grafting?

Background-We sought to determine whether location of the second internal thoracic artery (ITA) graft used for bilateral ITA grafting affects mortality and morbidity of patients with 3-system coronary artery disease and to identify factors associated with second ITA location. Methods and Results-From January 1972 to June 2006, 3611 patients with 3-system coronary artery disease underwent bilateral ITA grafting with one graft anastomosed to the left anterior descending system and the second to either the circumflex (n = 2926) or right coronary artery (n = 685) system. Follow-up was 9.2 +/- 7.2 years. Propensity score methodology was used to obtain risk-adjusted outcome comparisons between patients with the second ITA to circumflex versus right coronary artery. Hospital mortality (0.34% versus 0.58%; P = 0.4), stroke (0.96% versus 0.88%; P = 0.8), myocardial infarction (1.3% versus 0.73%; P = 0.2), renal failure (0.44% versus 0.29%; P = 0.6), respiratory insufficiency (3.5% versus 3.8%; P = 0.7), and reoperation for bleeding (3.4% versus 3.2%; P = 0.8) were similar in patients who received the second ITA to circumflex or right coronary artery and remained similar after propensity score adjustment. Late survival (86% versus 87% at 10 years) was also similar. Despite this, there was a gradual decline in ITA to right coronary artery grafting. Conclusions-Contrary to prevailing wisdom that the second ITA graft should be anastomosed to the next most important left-sided coronary artery in 3-system coronary artery disease, it may be placed to either the circumflex or right coronary artery system with similar early and late outcomes.