Replacement of the inferior vena cava and iliac veins with heterologous grafts in animal tests.

The use of a modified bovine collagen graft as a low-pressure conduit was investigated by implantation into the iliocaval system of dogs. In the 210 day observation period, a patency rate of 87.5% was achieved. Nearly all graft failures occured within the first 14 days following implantation; failure after that time did not seem to be dependent upon length of time of implantation. Progressive organization of the neointima was seen histologically. New smooth muscle fibers were observed in the neointima with electron microscopic evidence of reconstitution of the subendothelial membrane. Continuing resorption of graft collagen coincided with its replacement by newly developed collagen type III fibers in a surface-parallel orientation.