IN-VITRO AND IN-VIVO EVALUATION OF A SMALL-CALIBER VASCULAR PROSTHESIS FIXED WITH A POLYEPOXY COMPOUND

A small caliber vascular prosthesis obtained from an ovine internal th oracic artery (3.8-4.5 mm ID) fixed with a polyepoxy compound and trea ted with heparin has been evaluated. Cytocompatibility was evaluated i n vitro using human endothelial cells (HEC). HEC were obtained from hu man saphenous vein and cultivated in culture medium supplemented with 25% human serum. Graft segments were rinsed using a standard protocol proposed by the manufacturer. Tissue reaction was tested on a rabbit m odel of subcutaneous implantation. The patency rate and healing patter ns were evaluated comparatively with polytetrafluorethylene (PTFE) 4 m m ID prosthesis in a canine model of carotid interposition. Cytocompat ibility assay showed that there was low adhesion on vascular grafts (2 0 +/- 2% of endothelial cells seeded) and no growth of HEC on the graf t surface. The graft patency rate was 55% in both groups, and actuaria l freedom from occlusion was not different at 3 months (37.7 +/- 15% i n Denacol-fixed grafts versus 38.1 +/- 14% in PTFE). Histological stud ies on the biological grafts shows a frequent neointimal hyperplasia a t the anastomosis (5/12), a lack of endothelial cells lining the graft surface, a good preservation of the media, and a moderate inflammator y response in the adventicia. The Denacol-fixed graft has presented ex cellent surgical properties and preservation of the histological struc ture. Nevertheless, the patency rate was not improved when compared wi th the PTFE control graft.