No‐Touch Harvesting Technique of the Great Saphenous Vein Graft Affects Graft Flow Velocity During Coronary Artery Bypass Grafting

Objectives: We aimed to investigate whether the no‐touch (NT) harvesting technique for the great saphenous vein graft (SVG) affects graft flow velocity during coronary artery bypass grafting. Methods: The study included 132 and 138 conduits that underwent NT and conventional (CV) harvesting techniques, respectively (NT and CV groups, respectively). Transit‐time flow measurements and contrast‐enhanced computed tomography (CT) were performed to assess graft flow velocity and patency. Results: Intraoperative graft flows, assessed using a transit‐time flowmeter, were 40 ± 19 and 48 ± 27 mL/min/anastomosis in the NT and CV groups, respectively. Preoperative SVG diameters, assessed via vascular ultrasound, were 2.8 ± 0.7 and 2.8 ± 0.8 mm in the NT and CV groups, respectively. However, postoperative SVG diameters, measured using contrast‐enhanced CT, were 2.7 ± 0.5 and 3.5 ± 0.6 mm in the NT and CV groups, respectively, indicating a significant reduction in the NT group ( p < 0.01). Graft flow velocities, calculated from graft flow and vascular diameter, were 7.3 ± 4.2 and 5.4 ± 3.2 cm/s/anastomosis in the NT and CV groups, respectively, being significantly higher in the NT group ( p < 0.01). The incidence of postoperative occlusion was significantly lower in the NT group (two conduits, 1.5%) than in the CV group (10 conduits, 7.3%) ( p = 0.02). Significant differences were found in the 5‐year patency rates between the two groups (NT group, 98.4%; CV group, 92.9%; p = 0.04). Conclusions: The NT SVG harvesting technique prevents postoperative graft diameter expansion and significantly increases graft flow velocity and patency. Further randomized studies are needed to determine whether differences in blood flow velocity are essential for graft patency over an extended observation period.