PURPOSE: To prospectively evaluate the safety and effectiveness of adjunctive administration of abciximab observed within 30 days and at 6 months after randomization in patients undergoing endovascular revascularization of long-segment femoropopliteal occlusions. MATERIALS AND METHODS: The study was approved by the local ethical committee, and patients gave written informed consent. In a prospective, double-blind, placebo-controlled design, patients undergoing percutaneous treatment for long-segment (>5 cm) femoropopliteal occlusions were randomly assigned to receive abciximab or a placebo; all patients also received standard-dose heparin. Effectiveness and safety analyses were based on an intention-to-treat approach. Patency was calculated according to life-table analysis, and P values were derived from the log-rank statistic. The P values for dichotomous safety end points were calculated with the Fisher exact test. Odds ratios were calculated for subgroup analyses. Logistic regression modeling was used for analysis of the safety bleeding data. RESULTS: A total of 98 patients (103 limbs) were included: 47 patients received abciximab and 51 received a placebo. Patency with abciximab versus placebo was 95.7% versus 80.4% (relative risk, 0.21; 95% confidence interval: 0.05, 0.96; P =.02) at 30 days and was 61.7% versus 41.2% (relative risk, 0.57; 95% confidence interval: 0.32, 1.01; P =.03), coupled with a better clinical outcome according to the Rutherford score, at the end of follow-up (P =.03). Risk of major bleeding was not significantly increased, while access-site bleeding was significantly higher among patients receiving abciximab (odds ratio, 2.9; 95% confidence interval: 1.04, 8.2; P =.04). CONCLUSION: The data show that adjunctive administration of abciximab has a favorable effect on patency and clinical outcome in patients undergoing complex femoropopliteal catheter interventions not hampered by serious bleeding. Treatment effect of abciximab observed at 30 days was maintained at 6-month follow-up. (c) RSNA, 2005.