The use of long synthetic microvascular grafts in dogs with a view to clinical application.

Five centimetres long segments of 3 mm internal diameter synthetic expanded polytetrafluorethylene (E-PTFE) vascular graft (Gore-Tex) were implanted into the femoral arteries, proximal to the origin of the saphenous artery, of 10 mongrel dogs. In five cases saphenous island flaps were raised and the femoral artery was ligated distal to the saphenous origin so that a low flow system was created through the graft. In 10 femoral vessels the Gore-Tex graft was inserted without raising a flap and the distal femoral artery not ligated so that the graft acted purely as a conduit for blood flow to the distal limb. This created a high flow rate model compared to the reduced flow in the former group. In the first group flap survival was evaluated daily by direct observation of the flaps and graft patency was assessed every 48 h by means of Doppler ultrasound. None of these flaps survived longer then 48 h. In the second group, graft patency was monitored every 48 h with Doppler ultrasound and exploration of Gore-Tex grafts at 3 weeks showed that all had thrombosed.