Right Internal Thoracic Artery Patency Is Affected More by Target Choice Than Conduit Configuration

Although coronary artery bypass grafting using bilateral internal thoracic arteries (ITA) maximizes long-term survival, knowledge of the effect of different right ITA (RITA) inflow configurations on graft patency is limited. We have compared RITA occlusion among these configurations and identified its risk factors while adjusting for outflow coronary target location.

From January 1972 to January 2016, of 7092 patients undergoing bilateral ITA grafting at a single center, 1331 received one ITA to the left anterior descending coronary artery and had one or more evaluable postoperative coronary angiograms: 835 (63%) in situ, 496 free RITA grafts (311 [63%] originating from aorta; 98 [20%] left ITA [LITA], 76 [15%] saphenous vein graft, 11 [2%] radial graft). RITA occlusion reported on 1983 angiograms performed a median of 5.8 years later was estimated using nonlinear mixed-effects longitudinal modeling.

RITA patency was 90% at 1 year, 87% at 5 years, and 86% at 10 and 15 years. At 15 years, in situ RITA patency was 91% and free RITA patency from aorta was 91%, LITA 89%, and saphenous vein graft 77%. After adjusting for coronary target location and degree of stenosis, occlusion was similar in free RITAs from aorta (P = .15), LITA (P = .4), saphenous vein grafts (P = .13), and in situ RITAs. However, RITAs grafted to the left anterior descending coronary artery had fewer occlusions (P < .001), with patency similar to LITAs.

Among patients with bilateral ITA grafting requiring interval coronary angiography, long-term RITA patency was high and independent of its inflow configuration. Therefore, priority should be a RITA configuration optimizing its reach to important coronary targets, including the left anterior descending coronary artery.