Long-term outcome of the in situ versus free internal thoracic artery as the second arterial graft.

OBJECTIVES: The study objective was to determine the impact on outcome associated with using the second internal thoracic artery as a free compared with an in situ graft among patients who received the first internal thoracic artery as an in situ internal thoracic artery to the left anterior descending artery. METHODS: Among 2600 patients who underwent bilateral internal thoracic artery with an in situ internal thoracic artery to the left anterior descending artery, the second internal thoracic artery was used as a free graft bilateral internal thoracic artery in 136 patients and as an in situ graft (in situ bilateral internal thoracic artery) in 2464 patients. One-to-many propensity score matching was performed to produce a cohort of 134 patients with a second free graft internal thoracic artery matched to 2359 patients with a second in situ internal thoracic artery. Early and long-term outcomes including survival, hospital readmission, and repeat revascularization up to a maximum of 25.8 years were compared. RESULTS: There were no differences between the 2 matched groups' preoperative baseline characteristics and early adverse events. Long-term survival at 5, 10, and 15 years was significantly higher among patients with an in situ bilateral internal thoracic artery compared with patients with a free graft bilateral internal thoracic artery (hazard ratio free graft bilateral internal thoracic artery vs in situ bilateral internal thoracic artery, 1.53; 95% confidence interval, 1.14-2.10; P = .004). However, the long-term risk of readmission to the hospital for cardiovascular reasons and need for repeat revascularization were not significantly different between the 2 matched groups. CONCLUSIONS: In a small, propensity-matched cohort of patients undergoing coronary artery bypass grafting, the use of a second in situ internal thoracic artery was associated with an increase in late survival compared with the use of a second internal thoracic artery as a free graft. However, the risk of late hospital readmission and the need for repeat revascularization were similar.