Optimal Configuration for Bypass of the Left Anterior Descending Artery During Bilateral Internal Thoracic Artery Grafting

Background. The left internal thoracic artery (LITA) to left anterior descending (LAD) artery bypass remains the reference standard for coronary artery bypass graft surgery. With the advent of bilateral internal thoracic artery (BITA) grafting, optimal bypass configuration to the LAD is unclear. The objective of this study was to compare clinical outcomes between LITA-LAD and right internal thoracic artery (RITA)-LAD configurations in BITA grafting. Methods. The primary outcome was the need for percutaneous or surgical reintervention of the LAD. Secondary outcomes included all-cause mortality and cardiac mortality. Cox proportional hazard and competing risk models were used with entropy weighting. Results. Among BITA patients, 1527 had LITA-LAD grafts, and 523 RITA-LAD. Before entropy weighting, RITA-LAD patients were older with more diabetes, peripheral vascular disease, and left ventricular dysfunction, more urgent status (P < .05), and more frequently performed off-pump (P < .001). Need for repeat revascularization of the LAD territory at 10 years was 2.8% in the LITA-LAD group and 1.8% in the RITA-LAD group (subhazard ratio = 0.686; 95% confidence interval [CI], 0.296-1.589; P = .38). Adjusted survival at 10 years was 97.2% in the LITA-LAD group and 98.2% in the RITA-LAD group (hazard ratio = 1.056; 95% CI, 0.677-1.647; P = .81). There was no difference in cardiac mortality (subhazard ratio = 1.063; 95% CI, 0.502-2.251; P = .87). Conclusions. Use of either LITA or RITA for LAD grafting during BITA revascularization has no effect on long-term all-cause or cardiac mortality or need for repeat revascularization of the LAD. Cardiac surgeons should be confident in using a RITA-LAD bypass during BITA grafting. (C) 2020 by The Society of Thoracic Surgeons