Three hundred thirty-four patients with critical limb ischemia undergoing PTFE bypass to below-knee arteries were randomly assigned to have an ordinary PTFE graft or one with external support. Follow-up was scheduled until amputation, death, or at most 5 years, whichever event occurred first.
Patients in both the femoropopliteal and femorodistal groups were randomized to have an externally supported PTFE graft (101/195 patients in the femoropopliteal group and 72/139 patients in the femorodistal group). Follow-up information was available for 329 of 334 randomized patients (99 % ). At 1 year postprocedure, primary patency for below-knee bypass was 0.55 (95 % confidence interval [CI], 0.47-0.64) with and 0.42 (95 % CI, 0.34-0.50) without externally supported PTFE grafts, and secondary patency was 0.58 (95 % CI, 0.51-0.67) and 0.47 (95 % CI, 0.39-0.56), respectively. The corresponding figures for limb salvage were 0.75 (95 % CI, 0.68-0.82) and 0.69 (95 % CI, 0.62-0.77), respectively. The log rank test revealed statistically significant differences between patients with or without externally supported grafts for patency (primary patency: ¦Ö2 = 4.2 [degrees of freedom = 1; P = 0.041]; secondary patency: ¦Ö2 = 4.3 [degrees of freedom = 1; P = 0.037]) but not for limb salvage (limb salvage: ¦Ö2 = 0.2 [degrees of freedom = 1; P = 0.657]).
External support to a PTFE graft used for bypass to below-knee arteries improves primary and secondary patency but not limb salvage.