title: Experimental ovine model of primary venous valve incompetence: a pilot study.
abstract: OBJECTIVE
  To compare two techniques used to create a larger animal model of venous valve incompetence.
  
  
  METHODS
  To achieve vein dilatation as the primary cause of valve incompetence, common carotid jugular vein (JV) fistulas were created and optional filters were placed into the JV of sheep. Altogether, nine inferior vena cava filters were placed in three sheep in two stages. Six filters were placed caudal to the most caudal JV valve in three sheep and removed 6 weeks later. Then, three filters were placed across the most caudal valve in two sheep with competent valves and removed 3 weeks later. A common carotid artery-JV fistula was created in three sheep and followed-up for 1-3 weeks. Ascending and descending venograms were obtained to determine the JV sizes and function of their valves. The JVs removed at necropsy were studied with venoscopy.
  
  
  RESULTS
  Only one of the six JVs with filters caudal to the most caudal valve had incompetent valves after filter removal at 6 weeks. In addition, only one of three JVs with the filter across the valve had incompetent valves after filter removal at 3 weeks. At 1-3-week follow-up of the group with common carotid artery-JV fistula, all three JVs had incompetent valves in the cephalad vein portion, but only one JV had an incompetent valve in its caudal portion. At venoscopy, the incompetent valves showed various degrees of damage ranging from shortening to the destruction of valve leaflets.
  
  
  CONCLUSIONS
  Dilation of the valve annulus with a removable vena cava filter failed to produce valve incompetence. The promising results with the common carotid artery-JV fistula justify further detailed research.
authors.affiliation: Dotter Interventional Institute, Oregon Health & Sciences University, 3181 SW Sam Jackson Park Road, L-342, Portland, OR 97239-3098, USA.
authors.forename: Won Kyu
authors.initials: WK
authors.lastname: Park
authors.forename: Dusan
authors.initials: D
authors.lastname: Pavcnik
authors.forename: Brad
authors.initials: B
authors.lastname: Shirley
authors.forename: Wei
authors.initials: W
authors.lastname: Lu
authors.forename: Barry T
authors.initials: BT
authors.lastname: Uchida
authors.forename: Qiang
authors.initials: Q
authors.lastname: Yin
authors.forename: Hanno
authors.initials: H
authors.lastname: Hoppe
authors.forename: Man Kim
authors.initials: MK
authors.lastname: Duck
authors.forename: Long
authors.initials: L
authors.lastname: Liu
authors.forename: Frederick S
authors.initials: FS
authors.lastname: Keller
authors.forename: Josef
authors.initials: J
authors.lastname: Rösch
mesh_terms: D000818:Animals; D004195:Disease Models, Animal; D005260:Female; D010865:Pilot Projects; D011859:Radiography; D012756:Sheep; D020246:Venous Thrombosis / Q000000981:diagnostic imaging* / Q000503:physiopathology*