[Small-caliber polyurethane arterial prosthesis: clinical and angiomorphological follow-up of 20 patients in a prospective study].

The five year patency rate for femoropopliteal vein bypass grafts is around 70% according to the literature. Patency rates for synthetic grafts (eg PTFE, Dacron) range between 43 and 57%. If a vein is not available there is a new polyurethane 6 mm artery substitute on the market, that has shown in vitro promising physical characteristics and good long term results after implantation in dogs. In a prospective, randomized trial the results of the new polyurethane graft (PUR) were compared with those of a Dacron graft of the same diameter. Included in the study were 20 patients with lower limb ischemia stage Fontaine II B, III and IV, 10 in each group. Patency rates, handling of the graft and complications were analysed. During the one year follow up 7 PUR grafts had to be changed due to recurrent bypass occlusion within the first 3 months. At the end of the year there were only one PUR-bypass but 8 Dacron grafts open. 5 PUR grafts were examined histologically and no morphological reason for the occlusion, especially no myointimal hyperplasia, was found. A special regard was brought to the arterial run-off in both groups. It was confirmed to be comparable with only slightly better data for the PUR group. The exact reasons for the astonishing bad results of the PUR graft for femoropopliteal above knee bypass cannot be explained in our study. Due to the unexpected high occlusion rate the study was stopped earlier then planned.