Strut interlocking of titanium Greenfield vena cava filters and its effect on clot capturing: an in vitro study.

PURPOSE

To determine the influence of filter leg-interlocking on filtering efficiency of titanium Greenfield inferior vena cava filters in an in vitro model.

METHODS

Titanium Greenfield filters (TGF) were placed in an inferior vena cava (IVC) flow phantom with no interlocking legs, or with one or two pairs of legs interlocked. Clot emboli of varying sizes were introduced into the stream of flow, and the frequency of successful captures by the deformed filters was recorded.

RESULTS

Interlocking filter legs diminished the filtering efficiency of the TGF by up to 80% with the flow phantom in a horizontal position; no such compromise existed when the phantom was in a vertical position.

CONCLUSION

When leg interlocking is verified radiographically, the filtering efficiency of the TGF is reduced, and placement of a second IVC filter may be indicated.