title: Percutaneous retrieval of the Tulip vena cava filter: feasibility, short- and long-term changes--an experimental study in dogs.
abstract: OBJECTIVE
  To evaluate experimentally the retrievability of the Tulip inferior vena cava (IVC) filter in an in vivo study. Changes which accompany venous healing after filter retrieval were investigated.
  
  
  METHODS
  In 12 dogs, 23 filters were inserted percutaneously into the lumbar and intrahepatic segments of the IVC. Two weeks (n = 21 filters) or 3 weeks (n = 2 filters) after insertion, filter retrieval was attempted through an 11 Fr coaxial retrieval sheath system placed via the jugular vein. Follow-up studies before and after filter retrieval included cavography, computed tomography and intravascular ultrasound of the IVC. Seven dogs were killed immediately after filter retrieval to confirm short-term changes of the IVC, and 5 dogs were killed 6 months after filter retraction to evaluate long-term changes of the IVC related to filter retrieval. Post-mortem examinations and histologic specimens of the IVC were obtained to evaluate caval wall abnormalities secondary to filter removal.
  
  
  RESULTS
  All but one filter were successfully retrieved 2 weeks post-implantation. However, 3 weeks after insertion, filter retrieval was impossible. There were no complications caused by filter extraction. Follow-up studies after filter retrieval revealed no significant changes in the integrity, morphology or composition of the IVC and pericaval tissue. Histologic examination 6 months after filter retrieval revealed only flimsy fibrotic intimal plaques at the sites of former hook insertion.
  
  
  CONCLUSIONS
  The Tulip filter allows percutaneous insertion and retrieval up to 14 days after insertion, suggesting that it may be useful for either permanent or temporary prophylaxis against pulmonary embolism.
authors.affiliation: Department of Diagnostic and Interventional Radiology, Evangelisches und Johanniter Klinikum Duisburg, Germany. joe.g.neuerburg@ejk.de
authors.forename: J M
authors.initials: JM
authors.lastname: Neuerburg
authors.forename: S
authors.initials: S
authors.lastname: Handt
authors.forename: K
authors.initials: K
authors.lastname: Beckert
authors.forename: K
authors.initials: K
authors.lastname: Tonn
authors.forename: E
authors.initials: E
authors.lastname: Rasmussen
authors.forename: D
authors.initials: D
authors.lastname: Hunter
authors.forename: R W
authors.initials: RW
authors.lastname: Günther
mesh_terms: D000818:Animals; D020878:Device Removal; D004285:Dogs; D017743:Equipment Reuse; D005240:Feasibility Studies; D005500:Follow-Up Studies; D023421:Models, Animal; D011180:Postmortem Changes; D011474:Prosthesis Design; D019919:Prosthesis Implantation; D013997:Time Factors; D014057:Tomography, X-Ray Computed; D017539:Tunica Intima / Q000000981:diagnostic imaging / Q000473:pathology; D018084:Ultrasonography, Interventional; D014654:Vascular Patency / Q000502:physiology; D016306:Vena Cava Filters; D014682:Vena Cava, Inferior / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery