Optimal target vessel selection for composite and sequential radial artery grafting with an in situ internal thoracic artery

Objectives: We retrospectively evaluated graft patency in patients who underwent no-touch aortic arterial off-pump coronary artery bypass grafting to determine the optimal selection of target vessels for improved graft patency of composite and sequential radial artery I-grafts. Methods: The radial artery was anastomosed to the end of an in situ internal thoracic artery and was sequentially anastomosed to non-left anterior descending arteries. This composite graft was defined as an “I-graft.” We evaluated 145 I-grafts with 2, 3, or 4 sequential anastomoses (437 graft segments). A graft segment with the final distal anastomosis of every I-graft was defined as the last graft segment (LGS). When a sequential anastomosis was initiated from the left coronary branch, the I-graft assumed a clockwise course (69.0%). When a sequential anastomosis was initiated from the right coronary branch, the I-graft assumed a counterclockwise course (31.0%). Results: On multivariable analysis, right coronary branch (P < 0.001), moderately stenotic (50-75%) target vessel (P = 0.004), and LGS with moderately stenotic target vessel (P = 0.005) were predictors of mid-term graft occlusion. In situations where the LGS was anastomosed to a severely stenotic target vessel (>75%) with a clockwise course, when the number of moderately stenotic target vessels among sequential graft segments was 0, 1, or ≥2, the mid-term graft patency rates of I-grafts were 94.0%, 86.0%, and 81.4%, respectively. Conclusions: The selection of target vessels for severely stenotic lesions among sequential graft segments and the clockwise course enhance the mid-term graft patency of sequential radial I-grafts.