title: The optional VenaTech(™) Convertible (™) vena cava filter: experimental study in sheep.
abstract: OBJECTIVE
  Retrieval of optional caval filters may be impaired by filter tilting, migration, fracture, or embedding in the IVC wall. The goal of this experimental study was to evaluate a new optional filter, convertible by unlocking and removing the filter head.
  
  
  METHODS
  Forty-nine Pre-Alp sheep (average weight, 55 kg) were anesthetized. IVC was catheterized via the right femoral vein (n = 46) or via the internal jugular vein (n = 3) with a 12.9-F sheath. VenaTech(™) Convertible(™) IVC filters were inserted as either permanent filters (n = 14) or as filters to be converted. Conversion was immediately after deployment (n = 19) or delayed after 1, 3, or 6 months (n = 20). Filter delivery, deployment, and conversion with measurement of migration and tilting were evaluated by cavography. Incorporation of the filter's stabilizers and arms in the IVC wall was assessed by gross anatomy.
  
  
  RESULTS
  Delivery system insertion, filter release, and immediate conversion were successful in all cases. Delayed conversion was completed in all but one sheep, due to insufficient snare tension. Complimentary balloon-catheter inflation was required in 12 of 20 delayed conversions to achieve filter opening. In all 49 sheep, no thrombosis, migration, or significant tilting occurred. Within 4 weeks of conversion, the filter's stabilizers and arms were incorporated into the IVC wall. Upon removal, the filter head was free of intimal growth.
  
  
  CONCLUSIONS
  The VenaTech(™) Convertible(™) optional IVC filter was successfully implanted in all sheep with no migration or tilting. Conversion at various dates by filter head removal was feasible in all but one case.
authors.affiliation: University of Picardie-Jules Verne, Amiens, France. le_blanche.alain@chu-amiens.fr
authors.forename: Alain F
authors.initials: AF
authors.lastname: Le Blanche
authors.forename: Jean-Baptiste
authors.initials: JB
authors.lastname: Ricco
authors.forename: Michel
authors.initials: M
authors.lastname: Bonneau
authors.forename: Philippe
authors.initials: P
authors.lastname: Reynaud
mesh_terms: D015901:Angiography, Digital Subtraction; D000818:Animals; D003287:Contrast Media / Q000008:administration & dosage; D005268:Femoral Vein / Q000601:surgery; D007479:Iopamidol / Q000008:administration & dosage; D011474:Prosthesis Design; D034561:Sheep, Domestic; D014654:Vascular Patency; D016306:Vena Cava Filters; D014682:Vena Cava, Inferior
chemical_list: D003287:Contrast Media; D007479:Iopamidol