[Prosthesis replacement of the inferior vena cava]

The development of reconstructive venous surgery has been hampered by the lack of suitable graft materials. Fourteen carbon fibre grafts (phi: 8 mm), 30 glutaraldehyde treated ovine collagen grafts and 29 polytetrafluoroethylene (PTFE) grafts were used to replace a 35 mm segment of infrarenal inferior vena cava in pigs. Prostheses were removed 1 hour and 7, 14, 28, 56 and 112 days after implantation. All specimens were examined by light and scanning electron microscopy. The 112 day patency rate was 67% for ovine collagen grafts, while all carbon and PTFE grafts thrombosed. The difference was statistically significant (p less than 0.01). During the first hour after implantation, a thick (800-900 microns) thrombotic layer deposited on the inner surface of carbon grafts. This layer possibly caused the subsequent complete occlusion of the tubular segments. A thin neointima (less than 200 microns) developed on the flow surface of ovine collagen prostheses. This favoured complete endothelialization of the graft inner surface as soon as four weeks after surgery. In conclusion, glutaraldehyde treated ovine collagen would represent the first sound material to be used as venous substitute.