title: In vitro function of an adjustable temporary venous spring filter: comparison with the temporary RF02 filter and the permanent Greenfield vena cava filter.
abstract: OBJECTIVE
  The authors compared in vitro function of a temporary venous spring filter with that of a temporary RF02 filter and a permanent Greenfield filter.
  
  
  METHODS
  All three types of filters were placed in thin polyethylene tubes (diameters, 10.0-18.0 mm). Physiologic saline was substituted for flowing blood, and blood clots of three sizes (6 x 10 mm, 6 x 20 mm, 9 x 20 mm) were funneled to the filters. Clot-trapping ability of each filter and elevation of intraluminal pressure after clot trapping were assessed for each tube size.
  
  
  RESULTS
  No statistically significant elevation in intraluminal pressure was detected immediately after placement of any filter. The clot-trapping ability of the spring filter and of Greenfield filter were slightly lower than that of the RF02 filter, but the differences were not statistically significant. After filters had trapped large clots, a high pressure gradient was detected in the 10.0-mm tube for all filters. The spring filter was associated with a higher pressure than the other filters in the 12.0-mm tube (P < .05).
  
  
  CONCLUSIONS
  In vitro function of the spring filter was satisfactory in comparison with that of the RF02 filter and the Greenfield filter. For efficient filtering in the inferior vena cava, development of a larger version of the filter may be necessary.
authors.affiliation: Section for Experimental Radiology, National Hospital, University of Oslo, Norway.
authors.forename: J
authors.initials: J
authors.lastname: Hosaka
authors.forename: S
authors.initials: S
authors.lastname: Roy
authors.forename: K
authors.initials: K
authors.lastname: Kvernebo
authors.forename: I
authors.initials: I
authors.lastname: Enge
authors.forename: F
authors.initials: F
authors.lastname: Laerum
mesh_terms: D004867:Equipment Design; D066298:In Vitro Techniques; D008961:Models, Structural; D011655:Pulmonary Embolism / Q000517:prevention & control; D016306:Vena Cava Filters