title: Transjugular intrahepatic portosystemic shunts formed with polyethylene terephthalate-covered stents: experimental evaluation in pigs.
abstract: OBJECTIVE
  To evaluate the safety, efficacy, and tissue response associated with Wallstents covered with polyethylene terephthalate (PETP) compared with those associated with uncovered Wallstents for creation of transjugular intrahepatic portosystemic shunts (TIPS) in a porcine model.
  
  
  METHODS
  Thirteen TIPS were created in 13 minipigs: eight with PETP-covered Wallstents, five with standard Wallstents. Shunt venography was performed at 5-8 weeks, and necropsy was performed at 7-8 weeks. Histopathologic, immunohistochemical, and scanning electron microscopic examinations were performed.
  
  
  RESULTS
  Mean shunt stenoses of the control and graft groups were 45% and 53%, respectively. Graft stenoses involved the entire graft-bearing segment, whereas bare stent stenoses were localized within the liver tract. Myofibroblast and extracellular collagen matrix proliferation encompassed both control and graft-covered stents. There was one graft TIPS occlusion. One control TIPS stenosis was due to transstent proliferation of normal porcine hepatic tissue. A small focus of bile staining was seen on the abluminal surface of one TIPS, which was a patent PETP-lined shunt.
  
  
  CONCLUSIONS
  PETP graft TIPS provided equal, but not superior, patency to that of bare stent TIPS. The pattern of PETP TIPS graft healing differed from that of bare stents but was similar to that reported with other polyester graft vascular implants and consisted of diffuse transmural penetration and paving of the graft surface by extracellular collagen matrix and myofibroblasts.
authors.affiliation: Department of Radiology, Hospital of the University of Pennsylvania, Philadelphia, USA.
authors.forename: Z J
authors.initials: ZJ
authors.lastname: Haskal
authors.forename: L H
authors.initials: LH
authors.lastname: Brennecke
mesh_terms: D000818:Animals; D020099:Coated Materials, Biocompatible; D019544:Equipment Failure Analysis; D006083:Graft Occlusion, Vascular / Q000000981:diagnostic imaging / Q000473:pathology; D008855:Microscopy, Electron, Scanning; D010690:Phlebography; D011093:Polyethylene Terephthalates; D019168:Portasystemic Shunt, Transjugular Intrahepatic / Q000295:instrumentation*; D015607:Stents; D013552:Swine
chemical_list: D020099:Coated Materials, Biocompatible; D011093:Polyethylene Terephthalates