title: Experimental TIPS with spiral Z-stents in swine with and without induced portal hypertension.
abstract: OBJECTIVE
  To assess the suitability of spiral Z-stents for transjugular intrahepatic portosystemic shunt (TIPS) and the influence of portal hypertension on shunt patency in young swine.
  
  
  METHODS
  TIPS were established using spiral Z-stents in 14 domestic swine. In 7 animals, the portal venous pressure was normal; in the other 7, acute portal hypertension was induced by embolization of portal vein branches. Follow-up portal venography and histologic evaluations were done from 1 hr to 12 weeks after TIPS.
  
  
  RESULTS
  Follow-up transhepatic portal venograms showed progressive narrowing of the shunt, most prominent in the midportion of the tract. Ingrowth of liver parenchyma between the stent wires found after 3 weeks led to progressive shunt narrowing and shunt occlusion by 12 weeks. A pseudointima grew rapidly inside the stent, peaked in thickness around 4 weeks, and decreased later. Acutely created portal hypertension rapidly returned to normal and there was no difference in TIPS patency between the two groups of animals.
  
  
  CONCLUSIONS
  Although the spiral Z-stent can be used as a device for creation of TIPS in patients with cirrhotic livers, it is associated with extensive liver ingrowth in swine that leads to rapid shunt occlusion. Portal hypertension was only transient in this model.
authors.affiliation: Dotter Interventional Institute, Oregon Health Sciences University, Portland 97201, USA.
authors.forename: K
authors.initials: K
authors.lastname: Kichikawa
authors.forename: R R
authors.initials: RR
authors.lastname: Saxon
authors.forename: K
authors.initials: K
authors.lastname: Nishimine
authors.forename: N
authors.initials: N
authors.lastname: Nishida
authors.forename: B T
authors.initials: BT
authors.lastname: Uchida
mesh_terms: D000818:Animals; D004867:Equipment Design; D006975:Hypertension, Portal / Q000503:physiopathology* / Q000628:therapy; D008099:Liver / Q000473:pathology; D017082:Portal Pressure; D011169:Portal Vein / Q000473:pathology; D019168:Portasystemic Shunt, Transjugular Intrahepatic / Q000295:instrumentation*; D015607:Stents; D013552:Swine; D013997:Time Factors