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.