[Determining the effectiveness of percutaneous cava filters: experimental studies]. / Bestimmung der Effektivität perkutaner Kavafilter: Experimentelle Untersuchungen.

ABSTRACT

PURPOSE: In vitro clot-trapping capacity of 16 different caval filters should be evaluated under varying experimental conditions. MATERIAL AND METHODS: In a flow model simulating in vivo conditions (soft latex tube, dextran solution at 37 degrees C, pulsatile flow at a mean rate of 3 1/min) the efficiency of 16 caval filters was evaluated in horizontal and vertical position by using 640 or 1280 clots/filter (8 sizes). Non-self centering filters were tested in centric and in tilted position. RESULTS: Efficiency of optimally centered caval filters varied between 97.8 and 69.4%. The largest thrombi were captured by all optimal centered filters. A change from vertical to horizontal position of the flow model resulted in a variation of filter efficiency by about 4.8%. Efficiency of non-self centering filters decreased significantly when placed in a tilted position (mean decrease 15.5%; range 2.7%-37.7%) resulting in a deterioration of the capture rate by as much as 43.2%. CONCLUSION: Under optimal study conditions efficiency of all evaluated caval filters was high. Tilting of caval filters resulted in a significant efficiency decrease.