title: PTFE-encapsulated endovascular stent-graft for transjugular intrahepatic portosystemic shunts: experimental evaluation.
abstract: OBJECTIVE
  To evaluate the safety and efficacy of a stent-graft designed for a transjugular intrahepatic portosystemic shunt (TIPS), assess angiographic and hepatic biologic responses to polytetrafluoroethylene (PTFE)-encapsulated stents, and compare with a bare stent.
  
  
  METHODS
  Twelve TIPS (eight with flexible PTFE-encapsulated balloon-expandable stent-grafts and four control TIPS with bare Wallstents) were created in 12 pigs. Shunt venography was performed at 1-month intervals and necropsy of graft-containing animals at 1, 2, 3, 4, and 5 months. Control animals were sacrificed at 6 weeks. Detailed histopathologic analyses were performed.
  
  
  RESULTS
  The stent-grafts were readily deployed in all cases. Seven of eight graft TIPS remained fully patent during the follow-up period without luminal encroachment. Typical myofibrolasts proliferated on the abluminal surface of the graft, without extension into the lumen. No inflammatory reaction was present. Cellular overgrowth from the hepatic vein occluded the end of one graft at 3 months, partly related to rapid axial growth of that animal. The endoluminal surface of this shunt was otherwise patent. At 4-6 weeks, one control TIPS was occluded and the other three showed 45%-85% stenoses. No bile staining was seen in any case.
  
  
  CONCLUSIONS
  This PTFE-encapsulated stent-graft is biocompatible and safe to place. It markedly improves TIPS patency, providing almost uninterrupted, unimpeded patency in this model.
authors.affiliation: Department of Radiology, Hospital of the University of Pennsylvania, Philadelphia 19104, USA.
authors.forename: Z J
authors.initials: ZJ
authors.lastname: Haskal
authors.forename: A
authors.initials: A
authors.lastname: Davis
authors.forename: A
authors.initials: A
authors.lastname: McAllister
authors.forename: E E
authors.initials: EE
authors.lastname: Furth
mesh_terms: D000818:Animals; D001672:Biocompatible Materials; D001807:Blood Vessel Prosthesis; D019917:Blood Vessel Prosthesis Implantation; D011138:Polytetrafluoroethylene; D011169:Portal Vein / Q000473:pathology; D019168:Portasystemic Shunt, Transjugular Intrahepatic / Q000295:instrumentation*; D011172:Portography; D011474:Prosthesis Design; D015607:Stents; D013552:Swine
chemical_list: D001672:Biocompatible Materials; D011138:Polytetrafluoroethylene