Femoropopliteal angioplasty. Factors influencing long-term success. Prospective data was recorded on 217 percutaneous transluminal angioplasty (PTA) procedures performed in the superficial femoral and popliteal arteries over an 8-year period. After the initial procedure, patients were followed with serial noninvasive studies and, in 71 patients, repeat angiography. The mean follow-up period was 7 years (range, 2-11 years). Standard life-table survival analysis was used to assess the factors potentially affecting long-term outcome. Excluding an initial technical failure rate of 10%, overall patencies at 1, 3, and 5 years were 81%, 61%, and 58%, respectively. After the first year, the prognosis (i.e., failure rate) appears to be linear over the long term (i.e., up to 10 years). Factors negatively influencing long-term patency include the presence of diabetes mellitus, diffuse atherosclerotic cardiovascular disease, or threatened limb loss. Technical factors correlated with failure include lesion length, moderate eccentricity, and a poor post-PTA appearance. 