Pilot Study to Asses the Function and Patency of Polyester-Coated Composite Bypasses From Autologous Varicose Veins

Overview

If patients need to undergo bypass surgery, either an autologous vein can be used as bypass or, if there are no suitable veins are available, a prosthetic graft can be implanted. Varicose veins normally are judged not to be suitable as bypass. The ProVena vein support, made from polyester, is considered to strengthen varicose veins so that they they become suitable as bypass. Thereby, the advantages of an autologous bypass and the stability of polyester material can be combined. Patients that take part in the trial recieve an autologus bypass with a varicose vein, coated with ProVena. They are followed up at 3 and 6 months after implantation of a ProVena-coated bypass via duplex-sonography to assess the graft patency.

The ProVena trial is a non-randomised multi-centre trial, aiming to assess the suitability of the ProVena vein support. Currently, autologous veins are preferred to prosthetic grafts (Klinkert et al. 2004), but they are not considered to be suitable if they are varicose. Some early data indicate that these veins can be used if an external support is applied (Moritz et al. 1993, 1992, Neufang et al. 2003). The proVena vein graft has been tested in animal experiments. All bypasses showed a reduced intima hyperplasia, no disadvantages were found. Nevertheless, as a ProVena-coated bypass cannot be regarded as completely autologus, it is necessary whether the coating does not increase the risk of * infections * scar formation, reducing the patency * higher incidence of seroma ProVena is made from polyester filaments, similar to the material used for prosthetic grafts. As the material is used since years in peripheral bypass surgery, we do not expect increased risks. It is planned to include 50 Patients in 10 centres. Patients can be included if they match the eligibility criteria, need to undergo peripheral bypass surgery and have varicose veins normally not suitable to form a bypass graft. If patients agree to take part and give informed consent, baseline data are collected and the surgery is protocolled. Patients are followed up after 3 ands six months by duplex sonography. The inflammation parameters are detected via analysis of a blood sample. Main endpoints and secondary endpoints are as follows: Main endpoints: * Infection rate * primary patency * primary assisted patency * secondary patency Secondary endpoints: * complication rate * occurence of bypass stenosis * time needed for preparation of the bypass vein * technical success i. e. successful implatation of the ProVena Graft