We studied the factors that affected the primary patency and the clinical and procedural success of WALLSTENTS (stents) that were used at our institution from 1 March 1994 to 30 October 1995 for the treatment of iliac and femoral artery occlusive disease. This prospective study comprised 63 patients with 82 lesions. Follow-up was performed for a mean duration of 18.7 months. Pre- and post-procedural duplex ultrasonography, together with estimation of ankle-brachial index scores, was performed on all patients, and additional studies were performed at clinical follow-up if indicated. The technical success rate was 100%. Ankle-brachial index scores improved considerably from 0.52 +/- 0.21 before the procedure to 0.73 +/- 0.27 after the procedure. The significant predictors by univariate analysis of primary patency failure were: Fontaine class III or IV (P = 0.044); femoral location (P = 0.004); lesion length > 100 mm (P = 0.010); poor or moderate outflow (P = 0.026); and number of stents > or = 3 (P = 0.012). Cox regression analysis showed that > or = 3 stents (risk ratio = 5.61), poor or moderate outflow (risk ratio = 6.05), and femoral location (risk ratio = 5.18) were the significant predictors of primary patency failure. Femoral lesions required more stents than did iliac lesions (2.2 +/- 0.8 vs 1.3 +/- 0.5). Primary patency rates for iliac and femoral stents were 86% and 49%, respectively, at 12 months, and 82% and 41% at 24 months.