Experimental study on vascular graft. I. Replacement of inferior vena cava with crimped woven Tetoron (polyester) grafts and those reinforced with stainless steel coil

Experimental replacement of inferior vena cava with crimped woven Tetoron arterial graft was performed in dogs. Bypass-graft to thoracic inferior vena cava was not successful in two animals. Total repacement of thoracic inferior vena cava was attempted in four animals, and thoracoabdominal long implantation to inferior vena cava through diaphragm behind liver, followed by excision of thoracic inferior vena cava between the anastomoses, was done in 12 animals. Of these 16 animals, the graft was patent or not occluded in nine at autopsy between the 30th and the 451st day after implantation. Similar thoracoabdminal implantation of a graft reinforced with a steel coil was made in seven animals. Two grafts were patent at autopsy after 37 and 251 days, respectively. Abdominal vena cava replacement with a graft reinforced with a coil was undertaken in three animals. Two grafts were patent at autopsy after 117 and 142 days, respectively. On the whole, long term survival without occlusion over 30 days was obtained in fifteen/twenty-eight animals. Aside from the instances of simple bypassgraft and obvious technical errors in early experiments, it was in fifteen/ eighteen, and the graft was completely patent in ten/eighteen animals. The failures within 30 days resulted mostly from either lung complications or technical errors, and the latter were remarkable in the thoracoabdominal group where the graft reinforced with coil was used, but the application of the coil was very effective in protecting the graft against the compression by the adjacent organs. Tissue reaction to Tetoron was not noticeable and to the silk thread it was very slight and seemed not to affect long term success. By the present method even the total replacement of theracic inferior vena cava can be performed safely under normothermia and thoracoabdominallong implantation to inferior vena cava is also possible with considerable success. In order to prepare a more suitable synthetic graft for vein, it requires further search for harder, lighter, more elastic and physicochemically more stable material. The fabric of venous graft should be preferably more porous and thinner than that of the arterial graft available at the present in order to make the organization within the shortest time possible.