Temporary inferior vena cava filters: in vitro comparison with permanent IVC filters.
OBJECTIVE
An in vitro comparison of clot-trapping abilities of permanent and temporary inferior vena cava (IVC) filters.


METHODS
A flow model was used to simulate the IVC. Two permanent IVC filters, the titanium Greenfield and LG-Medical (LGM), were compared with two temporary filters, the Filcard International and Gunther. Clot sizes used were 2.5 x 2.5 mm, 2.5 x 5 mm, 5 x 5 mm, 5 x 10 mm, and 5 x 20 mm. Individual clots were presented to the filters with the simulated IVC in a horizontal or vertical orientation. Clot-trapping dynamics and pressure gradient changes during the injection of multiple, sequential clots were also examined.


RESULTS
As clot size diminished, all filters trapped fewer clots; however, the temporary filters trapped more small clots than the permanent filters. Very little difference was observed in clot-trapping abilities among the filters for clots of 5 x 10 mm or greater. In the horizontal orientation, the permanent filters trapped 38% of all clots delivered, while the temporary filters trapped 73%, chi 2 = 24.8 (P < .001). In the vertical orientation, the overall clot-trapping abilities of the filters improved, with the permanent filters trapping 73% of all clots delivered, while the temporary filters trapped 95%, chi 2 = 18 (P < .001). During trapping of multiple clots, the temporary filters allowed fewer clots to pass.


CONCLUSIONS
The temporary filters performed better than the permanent filters in both individual clot-trapping orientations. During multiple clot-trapping experiments, fewer clots were allowed to pass by the temporary filters. The temporary filters demonstrated the ability to capture clots both inside and outside the wire struts.
Stoneham
G W
GW
Department of Medical Imaging, Royal University Hospital, Saskatoon, Saskatchewan, Canada.
Burbridge
B E
BE
Millward
S F
SF
D000818:Animals; D001777:Blood Coagulation / Q000502:physiology; D004867:Equipment Design; D006801:Humans; D008955:Models, Cardiovascular; D011673:Pulsatile Flow; D013927:Thrombosis / Q000473:pathology*; D016306:Vena Cava Filters