Radial artery vs saphenous vein grafts for sequential coronary bypass grafting as a second conduit for the left coronary territory

Objective Although the radial artery graft has an adaptive property to flow demand, its flow characteristics in aorto-coronary sequential bypass grafting are not well elucidated. We evaluated the differences between the vein and radial artery grafts in the patency and the transit time flow meter-derived parameters (flow and pulsatile index), according to the stenosis rate of terminal target vessels and the number of anastomoses, in sequential bypass grafting to the left coronary territories as a second conduit. Methods We analyzed 222 patients who underwent isolated on-pump beating coronary artery bypass grafting with an aorto-coronary bypass to the left coronary territory. The patients were divided into radial artery group (n = 154) and vein graft group (n = 68). Sequential bypass was performed 1n 171 patients (127 radial arteries, 44 veins). Results Flow of the radial artery grafts was lower than that of the vein grafts (40.9 +/- 22.3 vs 47.5 +/- 23.8 mL/min, p = 0.044), while it became higher as the number of anastomoses per graft increased (1: 28.9 +/- 16.3 vs 2: 40.9 +/- 19.9 vs 3: 55.8 +/- 27.5, p < 0.001). The patency of radial artery grafts was better than that of vein grafts (98.0% vs 92.6%, p = 0.010; p < 0.001 after propensity score weighting). Conclusions Although intraoperative flow rate of the radial artery graft is lower, it has sufficient flow reserve for sequential bypass grafting, and its early patency is high enough. Radial artery is suitable for sequential bypass grafting to the left coronary territories as a second arterial conduit.