Aim. Expanded polytetrafluoroethylene (ePTFE) grafts are commonly used for femoropopliteal (FP) and femorocrural (FC) bypass grafting. Especially in below-knee (BK) reconstructions, patency is often inferior to the outcome in patients eligible for venous bypass grafting. This study assesses whether the Carmeda(R) BioActive Surface (CBAS), which employs covalent end-point linkage to retain heparin on the device surface, as it is used on the Propaten vascular graft successfully, can prolong patency. Methods. From June 2002 to December 2005,138 patients (97 men and 41 women; mean age: 73 years) received the CBAS-ePTFE graft for 153 infrainguinal bypass procedures. Seventy-five above-knee (AK) and 78 BK (including 37 FC) procedures were performed. Follow-up evaluations consisted of clinical examinations, ultrasonographic studies, and distal pulse assessments. Patency and limb salvage rates were assessed by using fife-table analyses. Results. The overall primary and secondary 2-year patency rates were 73.6% and 86%, respectively. Two-year primary patency rates according to bypass type were 76.2%, 72.6%, and 68.9% for AK FP, BK FP, and FC bypasses, respectively; the corresponding secondary patency rates were 87.5%, 87.8%, and 79.4%. The 2-year limb salvage rate in patients with critical limb ischemia (n=68) was 89.9%. Conclusion. Our findings show that CBAS-ePTFE bypass grafts appear to give prolonged patency rates and indicate that the use of this graft may represent a viable alternative for BK bypasses, which have traditionally yielded less than desirable outcomes. A prospective randomized trial is required to provide more definitive information about the graft's patency and limb salvage performance.