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 filt ering efficiency of titanium Greenfield inferior vena cava filters in an in vitro model. Methods: Titanium Greenfield filters (TGF) were pla ced in an inferior vena cava (IVC) flow phantom with no interlocking l egs, or with one or two pairs of legs interlocked. Clot emboli of vary ing sizes were introduced into the stream of flow, and the frequency o f successful captures by the deformed filters was recorded. Results: I nterlocking 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. Conclu sion: When leg interlocking is verified radiographically, the filterin g efficiency of the TGF is reduced, and placement of a second IVC filt er may be indicated.