title: In vitro evaluation of optionally retrievable and permanent IVC filters.
abstract: OBJECTIVE
  To systematically evaluate different optionally retrievable and permanent inferior vena cava (IVC)-filters with respect to their capture rates.
  
  
  METHODS
  Seven optionally retrievable and permanent IVC filters were tested in an in vitro flow model with a tube size of 22 mm in horizontal and vertical positions. To analyze the capture efficiency the IVC filters were implanted in concentric and eccentric positions and subsequently exposed to single and multiple blood clots of different sizes (3x5, 3x10, 5x10, 5x20, 7x20, 10x24 mm). Capture rates and pressure changes were measured and compared between the different IVC filters.
  
  
  RESULTS
  There were significant differences between the tested IVC filters. In general, the capture rate improved with increasing clot size (P<0.0001). In the single-clot exposure the highest mean capture rate was achieved with the Celect filter (90.4%+/-15.7%), whereas the Günther Tulip filter achieved best results in the multi-clot exposure (76.7%+/-12.5%). Capture rates differed significantly between the various IVC filters (single-clot: P<0.0001; multi-clot: P=0.0016). The position (horizontal or vertical) did not show a significant influence, whereas capture rates significantly decreased in the multi-clot test with eccentric filter positions (P=0.0299). In this study optionally retrievable IVC filters were more efficient than the tested permanent IVC filters (single-clot: P<0.0001; multi-clot: P=0.0002).
  
  
  CONCLUSIONS
  Optionally retrievable IVC filters are efficient. Clot size, IVC filter type, and position significantly influence capture rate. Deliberate selection of the most efficient IVC filter and concentric positioning are important to ensure optimal results.
authors.affiliation: Applied Medical Engineering, Helmholtz Institute, Department of Diagnostic Radiology, RWTH Aachen University, Germany. mahnken@rad.rwth-aachen.de
authors.forename: Andreas H
authors.initials: AH
authors.lastname: Mahnken
authors.forename: Jochen
authors.initials: J
authors.lastname: Pfeffer
authors.forename: Sven
authors.initials: S
authors.lastname: Stanzel
authors.forename: Anne
authors.initials: A
authors.lastname: Mossdorf
authors.forename: Rolf W
authors.initials: RW
authors.lastname: Günther
authors.forename: Thomas
authors.initials: T
authors.lastname: Schmitz-Rode
mesh_terms: D001777:Blood Coagulation / Q000502:physiology*; D004867:Equipment Design; D006801:Humans; D066298:In Vitro Techniques; D011655:Pulmonary Embolism / Q000517:prevention & control*; D013927:Thrombosis / Q000517:prevention & control*; D013997:Time Factors; D016306:Vena Cava Filters; D014682:Vena Cava, Inferior