IN-VITRO STUDIES OF TEMPORARY VENA-CAVA FILTERS

Purpose: To evaluate the clot trapping capacity of different temporary vena cava filters in a vena cava model. Methods: A vena cava flow mod el was built using PVC tubing, a hemodialysis membrane and a pulsatile pump. Blood was imitated by a Dextran 40 solution. Five different tem porary vena cava filters and two prototypes were tested using human th rombi. The mechanism of clot capture was observed. Results: Decreasing rank order according to decreasing percentage of clots captured for t he 21-mm diameter vena cava model was Cook (C) > Angiocor (A) > Cordis (CD) > Antheor (TF-6) > DIL for thrombi with a diameter of 3 mm and A > C > CD > TF-6 > DIL for 5-mm thrombi. In a cava with diameter of 28 mm, decreasing rank order was C > CD = A > TF-6 > DIL and C > CD = A > DIL > TF-6 for 3- and 5-mm thrombi, respectively. Two new prototypes , the TF-8 and TF-10 filters, achieved better results than the TF-6 fi lter and were in most conditions comparable to the A and CD filters. I n most cases, thrombi were trapped between filter and cava wall. Concl usion: The vena cava flow model demonstrates significant differences i n rates of clot capture (range 22%-98%) depending on cava diameter, th rombus size, and filter type.