The Thigh Saphenous Vein Versus the Calf Saphenous Vein: Searching for the Optimal Conduit for Coronary Artery Bypass Grafting.

BACKGROUND: The quality of saphenous vein (SV) grafts can vary depending on the site from which they are harvested. However, few studies have compared SV grafts harvested from the thigh with those harvested from the calf to explore which is more appropriate for use in coronary artery bypass grafting (CABG). In this study, we evaluated the graft patency rates of thigh and calf SV grafts over 5 years. We also assessed the functional and structural viability of SV endothelial and smooth muscle cells. METHODS: This retrospective observational study included 265 patients who underwent CABG performed by the same surgical team between 2015 and 2019. Each patient received one SV graft from either the thigh or the calf to the right coronary territory. The 1-, 3-, and 5-year postoperative coronary computed tomography (CT) angiography results were compared between patients who received the thigh and calf SV grafts. Surgical specimens were collected from 2015, which were evaluated by western blotting and immunohistochemistry to evaluate the expression, stability, morphology, and localization of von Willebrand factor (vWF), matrix metalloproteinase (MMP)-2, MMP-9, vimentin, and caveolin-1 (CAV-1). RESULTS: The 5-year coronary CT angiography results demonstrated a significantly higher patency rate for thigh SV grafts than for calf SV grafts (69.2% vs. 51.7%, p = 0.030). The protein expression of vWF, MMP-2, MMP-9, vimentin, and CAV-1 was significantly higher in calf SV grafts than in thigh SV grafts (all p ＜ 0.05). CONCLUSIONS: In this study, thigh SV grafts had significantly higher patency than calf SV grafts at 5 years after CABG. Moreover, the functional and structural viability of SV endothelial and smooth muscle cells in the thigh SV grafts were better preserved than those in the calf SV grafts. These findings suggest that thigh SV grafts appear to be more appropriate conduits than calf SV grafts for CABG.