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

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.

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.

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).

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.