In vivo evaluation of a retrievable vena cava filter : The Dibie-Musset filter : Experimental results

To evaluate, in an animal model, the efficacy and safety of a 7 Fr percutaneous vena cava filter for temporary or permanent use. The Dibie-Musset (DM) filter is a wire preformed into a double-spiral shape with a spring effect. The experiment was performed in 15 adult sheep and consisted of the insertion of 45 filters, clot trapping tests, and filter retrieval. Follow-up in all sheep consisted of radiologic (abdominal radiograph, inferior vena cavogram, abdominal computed tomography), macroscopic, and microscopic examinations between days 8 and 386 after filter placement. Of the 45 filters implanted in 15 sheep, 29 were retrieved between day 0 and day 15. Filtration efficiency was 100% for clots 4 x 4 x 20 mm. No long-term (1 year) side-effects were detectable. Microscopic examination of the vein wall showed only a dense intimal fibrosis without signs of acute inflammation at 1 year. These results support the efficiency and safety of the DM filter in an animal model.