PTFE-ENCAPSULATED ENDOVASCULAR STENT-GRAFT FOR TRANSJUGULAR INTRAHEPATIC PORTOSYSTEMIC SHUNTS - EXPERIMENTAL EVALUATION

PURPOSE: To evaluate the safety and efficacy of a stent-graft designed for a transjugular intrahepatic portosystemic shunt (TIPS), assess an giographic and hepatic biologic responses to polytetrafluoroethylene ( PTFE)-encapsulated stents, and compare with a bare stent. MATERIALS AN D METHODS: Twelve TIPS (eight with flexible PTFE-encapsulated balloon- expandable stent-grafts and four control TIPS with bare Wallstents) we re created in 12 pigs. Shunt venography was performed at 1-month inter vals and necropsy of graft-containing animals at 1, 2, 3, 4, and 5 mon ths. Control animals were sacrificed at 6 weeks. Detailed histopatholo gic analyses were performed.RESULTS: The stent-grafts were readily dep loyed in all cases. Seven of eight graft TIPS remained fully patent du ring the follow-up period without luminal encroachment. Typical myofib rolasts proliferated on the abluminal surface of the graft, without ex tension into the lumen. No inflammatory reaction was present. Cellular overgrowth from the hepatic vein occluded the end of one graft at 3 m onths, partly related to rapid axial growth of that animal. The endolu minal surface of this shunt was otherwise patent. At 4-6 weeks, one co ntrol TIPS was occluded and the other three showed 45%-85% stenoses. N o bile staining was seen in any case. CONCLUSION: This PTFE-encapsulat ed stent-graft is biocompatible and safe to place. It markedly improve s TIPS patency, providing almost uninterrupted, unimpeded patency in t his model.