Bilateral internal mammary artery Y construct with multiple sequential grafting improves survival compared to bilateral internal mammary artery with additional vein grafts: 10-year experience at 2 different institutions

OBJECTIVES: Utilization of bilateral internal mammary arteries (BIMAs) has been shown to improve long-term outcomes in patients undergoing coronary artery bypass grafting. To achieve complete revascularization, BIMAs may be used as either sole conduits for revascularization through a Y-graft configuration (BIMA-Y) or deployed with additional grafts used in conjunction with BIMAs. The purpose of this study was to compare the long-term outcomes of two institutions that predominantly used either the BIMA-Y configuration or BIMA plus additional grafts to achieve optimal revascularization. METHODS: From 1 January 2000 to 31 December 2010, 436 patients were revascularized using a non-sequential BIMA grafting at one institution (Group A), with veins being used for additional targets. At the second institution (Group B), 771 patients were revascularized using a BIMA-Y graft for all distal targets. Kaplan–Meier analysis was used to compare unadjusted survival between the groups. Cox proportional hazards regression modelling was used to provide an adjusted comparison of survival between the groups. RESULTS: There was no statistically significant difference between the average number of anastomotic sites used in Group A and Group B (A = 4.0 ± 0.7 vs B = 4.0 ± 0.7; P = 0.24). Group A did not have a significantly greater in-hospital mortality (0.7% vs 1.0% P = 0.39), stroke (0.5% vs 0.8% P = 0.40), deep sternal wound infection (0.0% vs 0.6% P = 0.11) or reoperation for bleeding (1.6% vs 0.6% P = 0.10) than Group B. Cox proportional hazards analyses demonstrated that at 14 years, Group B had a significantly improved survival compared to Group A (Group B = 88% vs Group A = 81%) with an overall reduction in mortality (adjusted hazard ratio 0.780, 95% confidence interval 0.448–0.849; P = 0.043). CONCLUSION: Utilization of the BIMA-Y configuration was associated with improved survival when compared to BIMA grafting with additional vein grafts. Further studies are necessary to evaluate the efficacy of BIMA-Y grafting against other means of providing complete arterial revascularization.