Thrombogenicity and long-term patency in autologous vein, polytetrafluoroethylene (PTFE) and silk grafts in a sheep model: evaluated through the use of indium-III-labeled platelets.

Vascular conduits have different thrombogenicity and since platelet sequestration onto a graft surface is a contributing factor for subsequent graft occlusion, this constitutes an important feature. Most studies on thrombogenicity have been done as short-term experiments. In the present communication we have evaluated graft thrombogenicity for autologous vein, polytetrafluoroethylene (PTFE), and pure chinese silk grafts, immediately after graft implantation, 1, and 2 months thereafter, using Indium-111-labelled platelets, evaluated platelet consumption, and studied patency up to 4 months after graft implantation in a sheep model. The least thrombogenic graft material was found to be the autologous vein, followed by the silk graft and the PTFE graft. Already 1 month after graft implantation healing of the grafts seems to have occurred, resulting in a minimal detectable platelet sequestration. Platelet consumption by the graft can be seen as a decrease in platelet count in the peripheral blood. Four months after graft implantation the autologous vein grafts showed a patency rate of 71%, the silk grafts 55%, and the PTFE grafts 38%. The pure silk prosthesis revealed though at harvest of the grafts, a high incidence of aneurysmal graft dilatation.