Long-Term Patency of Individual Segments of Different Internal Thoracic Artery Graft Configurations

Background: Internal thoracic artery (ITA) grafts are the most durable conduits available for coronary artery bypass grafting (CABG). However, little is known about long-term angiographic outcomes of ITA grafts used in different configurations and whether sequential or Y grafting compromises patency of the inflow ITA graft. Methods: From January 1972 to August 2016, 60,500 patients underwent primary isolated CABG, of whom 326 received ITA grafts placed in sequential or Y configuration and were studied angiographically (median 4.8 years to first follow-up angiogram). Each sequential or Y segment was studied individually using a mixed-effects longitudinal model with the patient as the random effect. Results: At 15 years, patency of the proximal ITA segment (n = 331) was 99%; of a sequential segment (n = 222), 97%; and of the segment beyond anastomosis of a Y graft (n = 109), 99%. Patency of the Y grafts (n = 109) was 92% at 5 years, 91% at 10 years, and 90% at 15 years. After adjusting for proximal stenosis and graft location, Y grafts were associated with greater occlusion than the inflow segment of ITA grafts (odds ratio; 51, 95% confidence interval, 6.1 to 422; p = 0.003) and of sequential grafts (odds ratio, 12; 95% confidence interval, 1.14 to 120; p = 0.04). Conclusions: Long-term patency of ITA grafts in sequential or Y configuration is similar qualitatively, but not quantitatively, to the known patency of single ITA-to-left anterior descending grafts. Sequential or Y grafting does not compromise patency of the inflow portion of an ITA graft. Y-graft patency is lower than sequential graft patency but is still better than known patency of saphenous vein grafts.