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.
Department of Medical Imaging, Royal University Hospital, Saskatoon, Saskatchewan, Canada.
G W
GW
Stoneham
B E
BE
Burbridge
S F
SF
Millward
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