8 YEARS OF CLINICAL ENDOTHELIAL-CELL TRANSPLANTATION - CLOSING THE GAP BETWEEN PROSTHETIC GRAFTS AND VEIN GRAFTS

After years of in vitro studies and non human primate implantations, t he authors commenced their clinical program of autologous in vitro end othelialization of polytetrafluoroethylene (ePTFE) grafts in 1989. Bas ed on the successful 3 year results of a pilot study (Phase I) with 49 patients (1:2 randomization, assigning 33 patients to the endothelial ized group and 16 to the control group), the authors offered in vitro endothelialized grafts to all patients who did not have a suitable sap henous vein available from tune 1993 onward (Phase II). Another 72 pat ients received 81 successfully endothelialized ePTFE grafts in this se cond phase of the transplantation program. In the Phase I randomized t rial, the Kaplan-Meier survivorship analysis showed a primary 3 year p atency rate of 84.7% for endothelialized grafts and 55.4% for control grafts. After 5 years, it was 73.8% for the endothelialized group and 20.8% for the controls. At the end of the 7 year follow-up period, the primary patency rate for endothelialized grafts remained high at 73.8 %, whereas that for the control grafts dropped to zero (log-rank test; p = 0.001 and Wilcoxon test; p = 0.003). The subsequent Phase II rout ine clinical implantation of endothelialized ePTFE grafts showed a 3 1 /2 year primary patency rate of 72.9% for all femoropopliteal reconstr uctions. The authors' overall 7 year follow-up with endothelialized fe moropopliteal ePTFE grafts (n = 108) shows a patency of 66.0%. When pr etreated with fibronectin (n = 43), the 7 year patency was 72.1%. In t he above-knee group, the 7 year patency for fibronectin treated grafts was as high as 75.8% (n = 36). After 8 years of clinical endothelial cell transplantation, the authors conclude that in vitro endothelializ ation of ePTFE grafts results in a patency rate of arterial prostheses comparable with that of vein grafts.