Percutaneous retrieval of the Tulip vena cava filter: feasibility, short- and long-term changes--an experimental study in dogs.

ABSTRACT

PURPOSE: 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. CONCLUSION: 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.