Purpose: To assess the relationship between plasma homocysteine levels and restenosis after femoropopliteal percutaneous transluminal angioplasty.Methods: Over a 10-month period, 128 consecutive, symptomatic patients (72 men; median age 70 years) having successful femoropopliteal angioplasty for atherosclerotic occlusive disease were prospectively enrolled in the study. Plasma homocysteine levels were determined the day before the procedure. The primary endpoint was restenosis >50%, documented by duplex sonography, at up to 12 months' follow-up. Cox proportional hazards analysis was used to determine the risk of restenosis in relation to pretreatment homocysteine levels.Results: The restenosis rate at 12 months was 46%. Median baseline plasma homocysteine levels were not different in patients with and without restenosis (15.4 versus 16.7 micromol/L, p=0.30). Compared to patients with homocysteine levels </=14 micromol/L (lower tertile, n=43), the hazard ratio of incident restenosis was 0.75 (95% CI 0.40 to 1.40) in patients with homocysteine levels from 14.1 to 19.6 micromol/L (middle tertile, n=42) and 0.64 (95% CI 0.33 to 1.22) in patients with homocysteine levels >/=19.7 micromol/L (upper tertile, n=42) (p=0.38). Multivariate analysis showed that lesion length (p<0.0001) and lack of hypertension (p=0.0013) were associated with restenosis.Conclusions: Elevated plasma homocysteine levels are not associated with restenosis after femoropopliteal angioplasty. Therefore, plasma homocysteine cannot be considered as an important risk factor influencing the outcome after initially successful angioplasty in femoropopliteal arteries.