OVERCOMING FAILURE OF VENOUS VASCULAR PROSTHESES

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  • 1 January 1984
    • journal article
    • research article
    • Vol. 96  (3) , 503-510
Abstract
Thrombogenicity of graft material, low velocity of blood flow and wall collapsibility have been cited as the main factors responsible for the high occlusion rate of vascular prostheses placed in the venous system. The effects of measures taken to overcome each of these factors were analyzed. The thrombogenicity of expanded polytetrafluoroethylene (ePTFE) was evaluated by determination of the 3-h deposition of radionuclide-labeled platelets and fibrin on grafts placed in the infrarenal ven cava of 18 dogs. Wetting of prosthesis with heparin before implantation significantly decreased platelet deposition at the cranial anastomosis (P < 0.025) and on the graft surface (P < 0.01), whereas the decrease of fibrin deposition was not statistically significant. The effets of flow velocity and graft support were studied in 44 dogs subjected to iliocaval bypass. A flow-increasing arteriovenous fistula evidently was necessary to maintain patency of ePTFE grafts (P < 0.01) but did not enhance patency of autogenous vein grafts. External ring support of ePTFE grafts did not significantly improve early patency. Decreasing thrombogenicity by wetting the grafts with heparin and increasing the blood flow by constructing an arteriovenous fistula helps in overcoming failure of venous vascular prostheses.