Saphenous Vein Endothelial Cell Viability: A Comparative Study of Endoscopic and Open Saphenectomy for Coronary Artery Bypass Grafting

BACKGROUND: The use of endoscopic saphenous vein harvesting (ESVH) for coronary artery bypass grafting (CABG) is growing. This study was done to investigate the extent of endothelial injury in ESVH compared with that of the standard open method (OSVH), and under various physical and chemical preservation factors. METHODS: We endoscopically removed the saphenous vein from 45 consecutive patients undergoing saphenectomy for CABG together with a segment retrieved by the no-touch OSVH method. Vein samples from each group were divided into 8 subgroups of 5 samples each, and incubated in Plasma-Lyte solution with or without papaverine, at distending pressures of 100 or 300 mm Hg, and at either 4°C or 28°C, respectively. A ninth subgroup was preserved at room temperature without pressure or papaverine. The viability of cultured saphenous vein endothelial cells was assessed by counting the number of total cells and deriving the proportion of viable cells, following incubation for 72 hours. RESULTS: The median proportion of viable cells (PVC) showed a slight decline over days 0 to 4 for both harvesting methods. No significant difference existed in the median PVC between the two techniques (day 0: 75%, 72%, P = 0.8; day 1: 66.7%, 66.7%, P = 0.9; day 2: 66.7%, 66.7%, P = 0.3; day 3: 65.3%, 66.7%, P = 0.16, respectively). The mean PVC compared across temperatures of 4°C, 28°C, and room temperature for the ESVH was highly significant, with the highest value being for room temperature (69.5%, 56.4%, 70.3%, respectively, P = 0.0003). Results for the OSVH were not significant. The effect of distension pressure did not vary significantly for 0, 100, and 300 mm Hg for both techniques (70.3%, 63.2% and 63.4%, respectively, P = 0.46 for the ESVH; 66.5%, 68.4%, 67.4%, respectively, P = 0.94 for the OSVH). The addition of papaverine improved PCV slightly for the OSVH only (61.7%, 64.3%, respectively, P = 0.02), whereas that for the ESVH was not significant (67.3%, 72.5%, P = 0.12). CONCLUSION: The effect of ESVH on endothelial cell viability is comparable to that of the OSVH. Among the factors influencing endothelial viability during vein preparation, temperature had a major effect with lower temperatures in the range of 4°C to room temperature being the most favorable one. Mechanical distension and papaverine had unimportant or inconsistent roles. We recommend the ESVH as the procedure of choice for saphenous vein harvesting due to the lower postoperative morbidity, and the lower incubation temperature needed for its better influence on potential graft patency.