Midterm results of coronary artery bypass graft surgery with internal thoracic artery under low free-flow conditions

Background We use the left internal thoracic artery (LITA) even when flow is very low. In this study, we investigated midterm outcome of coronary artery bypass graft surgery with low free-flow LITA. Methods One hundred patients undergoing coronary artery bypass graft surgery using LITA with a free flow of less than 20 mL/min were reviewed. The mean follow-up duration was 47.4 months, ranging from 1 to 65 months. Graft angiography was performed postoperatively. The diameter of the LITA was assessed angiographically. Cumulative graft patency, cardiac-related event-free rate, and actuarial survival rate were calculated by the Kaplan-Meier method. Results An early postoperative Doppler study showed that the diastolic-to-systolic ratio in the LITA was 1.76 ± 0.33. A 1-month postoperative angiography revealed LITA string sign in 2 patients. One had a percutaneous coronary intervention, whereas string sign was not detected in the second patient, and LITA patency showed a marked improvement in 1-year postoperative angiogram. One month postoperatively the LITA diameter was 1.6 ± 0.4 mm, and significantly enlarged in the second angiogram (1.9 ± 0.4 mm, p = 0.0003). There was a significant correlation between the diameter of the LITA and the left anterior descending coronary artery (r = 0.889, p = 0.0001). The cumulative graft patency rate at 1 and 4 years was 99.0% and 94.3%, respectively. The cardiac-related event-free rate at 1 and 5 years was 97.0% and 93.3%, respectively. The actuarial survival rate at 5 years was 97.1%. Conclusions Even with a very low LITA free flow, graft function improves with LITA growth, if there was no mechanical damage that impedes recovery.