['Single-segment great saphenous vein (ssGSV) is the conduit of choice in infrainguinal bypass for critical limb ischemia (CLI). The aim of this study was to assess results of other autologous vein grafts and risk factors for graft stenosis development and graft failure. The purpose was also to evaluate outcome of patients with high operative risk undergoing infrainguinal alternative autologous vein bypass for CLI.', 'We retrospectively reviewed 1,109 consecutive infrainguinal bypasses performed between 2000 and 2007 for CLI. Rate and type of operations needed to maintain graft patency were evaluated. Outcome of different types of vein grafts in terms of primary patency, assisted primary patency, secondary patency, and limb salvage was assessed using Kaplan-Meier method. Predictors of poor outcome as well as patient- and graft-related risk factors for graft revision and graft failure were analyzed using multivariate analysis.', 'Median follow-up period was 37 (0-121) months. Primary patency, assisted primary patency, secondary patency, and limb salvage at 1 and 3 years were significantly better in ssGSV graft group than in alternative autologous vein graft (AAVG) group-74.4% and 67.1% versus 53.7% and 42.0% (P < 0.0001), 82.8% and 78.2% versus 67.2% and 57.8% (P < 0.0001), 84.8% and 80.8% versus 69.9% and 61.4% (P < 0.0001), and 88.9% and 86.9% versus 83.0% and 77.2% (P < 0.0001), respectively. In multivariate analysis, non-ssGSV graft was the only independent risk factor for the graft stenosis development (relative risk [RR]: 2.62, 95% confidence interval [CI]: 1.56-4.38, P < 0.0001), for graft occlusion (RR: 2.27, 95% CI: 1.52-3.40, P < 0.0001), and for graft failure (stenosis or occlusion) (RR: 2.00, 95% CI: 1.39-2.88, P < 0.0001). Revision rate of non-ssGSV conduits was higher than that of ssGSV grafts (18% vs. 12%, P = 0.007). High-risk patients (age of >80 years, coronary artery disease, estimated glomerular filtration rate of <30 mL/min/1.73 m(2)) who underwent bypass with arm vein or spliced vein had extremely poor outcome (1-year leg salvage rate and survival rate of 71.4% and 28.6%, respectively).'] Is outcome of infrainguinal single-segment great saphenous vein bypass for critical limb ischemia superior to alternative autologous vein bypass , especially in patients with high operative risk?