Comparison between externally stented and unstented PTFE vascular grafts.

It has been suggested that external stenting of synthetic vascular prosthetic material may improve patency rates in the low flow situation or across joints. This study compared externally stented polytetrafluoroethylene (PTFE) vascular grafts placed across the hip joint in dogs with nonstented PTFE grafts in regard to patency. Twenty animals underwent bilateral common iliac to common femoral artery bypass with proximal ligation of the femoral artery. In each animal one groin was randomly assigned to receive stented PTFE and the other nonstented PTFE. One animal was sacrificed at 2 weeks for graft infection. Nineteen animals received 38 grafts that remained in place 90-120 days. Patency was confirmed with angiography prior to sacrifice. Overall patency was 65 per cent with no significant difference between the two types of graft. Eighteen of 19 dogs (95%) had both the stented and nonstented PTFE grafts either open or closed. It is concluded that intrinsic factors, rather than external graft support, are a more important influence on graft patency in this model.