Short-term patency and safety of an expanded polytetrafluoroethylene encapsulated endoluminal device at the venous anastomosis of a canine arteriovenous graft model

PURPOSE: To determine the safety and short-term patency of a polytetrafluor oethylene (PTFE)-encapsulated carbon-lined endoluminal device (ED) deployed across the venous anastomosis of arteriovenous conduits. MATERIALS AND METHODS: Arteriovenous grafts (n = 16) were created between f emoral arteries and veins in eight female canines and allowed to mature 30 days +/- 5 (SD). Five were excluded before implantation because of thrombos is or intragraft stenosis. Deployment was conducted in the remaining 11 ana stomoses. Fistulography and intravascular ultrasound (IVUS) were performed before and after the procedure and 1 month postimplantation. Stent migratio n, apposition, and stenosis were evaluated. The angle of the anastomosis wa s compared before and after deployment and at follow-up. Mural thrombus thi ckness, percentage of surface covering, and percentage of endothelializatio n within the device were measured histologically. RESULTS: There was no significant migration. By explant, all devices were c ompletely apposed. Stenosis occurred in three of nine grafts. The angle of the venous anastomosis decreased by 29.5 degrees (posteroanterior) and 32.4 degrees (oblique) after ED deployment. There was a further decrease of 6.1 degrees (posteroanterior) and 3.2 degrees (oblique) during the 4-week foll ow-up period. Hemostasis was difficult to achieve in this animal model. Fiv e required more than 1 hour to achieve hemostasis manually. Six in three an imals were closed with a Perclose device, achieving immediate hemostasis; h owever, three (one in each animal) re-bled intermittently 2 weeks after imp lantation for an average of 9.3 days. The puncture site of each graft that bled was radiographically shown abnormal. CONCLUSION: The ED can be deployed without stent migration and is completel y apposed and patent after 4 weeks. Although bleeding was a problem with th is animal model, delayed bleeding complications associated with puncture si te abnormalities were seen only in grafts closed with a percutaneous suturi ng device.