Myocardial Revascularization Exclusively With Bilateral Internal Thoracic Arteries in T-Graft Configuration: Effects on Late Survival

Abstract

We studied long-term survival using bilateral internal thoracic artery (BITA) grafting in a T-configuration exclusively versus using single internal thoracic artery (SITA) grafting in patients with multivessel disease. Consecutive coronary operations performed at a single center between 1996 and 2014 were reviewed. Long-term survival among patients receiving coronary revascularization exclusively with BITA grafting in a T-configuration (n= 2,098) versus SITA grafts plus other types of conduits (saphenous vein graft [SVG] and radial artery [RA]) grafts (n= 1,659). In patients who underwent BITA grafting, the left internal thoracic artery (LITA) was grafted mainly to the left anterior descending artery, whereas the right internal thoracic artery (RITA) was used more commonly to graft the circumflex (Cx) artery and the right coronary system as T-grafts. A total of 485 pairs of patients were matched using propensity scores. Cox proportional hazard models were generated to examine the association of arterial BITA grafting with mortality. Patients in the BITA group were more likely to be younger (BITA, 63.7 ± 9.1 versus SITA, 65.0 ± 9.9; p<0.0001). At 30 days, patients who underwent BITA grafting experienced reduced unadjusted mortality (BITA, 1.2% versus SITA, 4.4%; p < 0.0001). At 10 years, patients who underwent BITA grafting experienced superior unadjusted survival (BITA, 82.6% ± 1.8% versus SITA, 76.1% ± 1.3%; p= 0.001). Cox regression analysis in the entire study cohort showed that BITA grafting was associated with improved survival (hazard ratio [HR], 0.71; 95% confidence interval [CI], 0.58-0.87; p < 0.001). In the propensity-score-adjusted analysis, patients who underwent BITA grafting had similar in-hospital mortality (BITA, 1.6% versus SITA, 2.9%; p= 0.196). Patients who underwent BITA grafting still showed improved survival at 10 years (BITA, 81.0% ± 4.1% versus SITA, 71.8% ± 2.5%; p= 0.039). This study suggests that coronary artery operations exclusively with BITA grafting in a T-configuration may be associated with better long-term survival than grafting with SITA plus other types of conduits.