Long-term retrieval of modified Günther Tulip vena cava Filters: an animal study.

We modified the Günther Tulip Filter to allow long-term retrieval and tested this modified filter design in an animal experiment. Fourteen modified Günther Tulip Filters (Celect filter) were inserted percutaneously into the inferior venae cavae of 7 domestic adult sheep (2 filters per animal). Before removal, 3 months after filter placement, cavography was performed and the filters were removed. Subsequently, cavography was obtained to check for any signs of bleeding. All venae cavae were prepared, removed, and macroscopically examined for bleeding. Filter placement was easy and successfully performed in all cases. No thrombi were detected inside the filters. All cases showed some narrowing of the vena cava at the level, where the filter legs were connected with the vessel wall. Neither cavograms after filter removal nor macroscopic examinations of the perivascular vena cava tissue showed any significant bleeding. The modified Günther Tulip Filter allowed for successful and uncomplicated filter removal up to 3 months after placement.