Bilateral Internal Thoracic Artery Composite Y Grafts: Analysis of 464 Angiograms in 296 Patients

The use of bilateral internal thoracic arteries (BITA) in coronary artery bypass graft surgery improves patient survival. The optimum BITA graft configuration is unknown. This study evaluates outcomes after the use of bilateral internal mammary Y grafting as the primary grafting strategy.

Patients who underwent BITA composite Y grafting (n = 1,011) between October 1994 and March 2009 were identified from a cardiac surgical database. Follow-up (mean 12 years) was obtained by cross-reference with the state death registry and local cardiology databases.

Perioperative mortality was 1.6%. Kaplan-Meier 10-year survival was 87.2%. There were 464 episodes of postdischarge angiography in 296 patients, at an average of 5.5 years to first angiography. Graft failure occurred in 151 patients, predominately affecting the right ITA limb (n = 139). Degree of native vessel stenosis (odds ratio [OR] 0.66 per 10% increase), anatomic territory grafted (circumflex OR 2.64, right coronary OR 6.73 versus anterior), and end-to-side free wall anastomoses (OR 1.98) predicted anastomotic occlusion. The left anterior descending artery graft patency was unaffected by sequential grafting. Progression to graft failure after the first angiogram was rarely seen in the 111 patients who had serial angiography.

Outcomes of BITA Y grafting are similar to those for other BITA configurations. The rate of presentation with arterial graft dysfunction decreases over time. Although competitive flow affects anastomotic patency, there is no threshold at which risk of occlusion substantially increases.