A new self-convertible inferior vena cava filter: Experimental in-vitro and in-vivo evaluation

Purpose: To evaluate using in-vitro and in-vivo models the feasibility and capture efficiency of a new self-convertible inferior vena cava filter (SCF), equipped with a biodegradable self-converting switch. Materials and Methods: Capture rates were tested in an in-vitro flow model for simulated supine and upright positions with clot diameters of 3 mm and 5 mm and tube diameters of 22 mm, 25 mm, and 28 mm. In the in-vivo study, five filters were implanted in five adult dogs. Venography was performed after the procedure every 2 weeks until filter conversion. Results: All filters were successfully implanted and completely converted with a mean trapping efficiency of 75.5% in the in-vivo study. The SCF was most efficient at 92% in the upright orientation with 5-mm clots and a 22-mm caval diameter. All five filters exhibited successful delivery and conversion in vitro. The SCFs were manually manufactured without barbs or hooks, and because of this feature, migration occurred. Conclusions: The SCF is feasible and highly efficient and converts itself successfully. Evaluation is planned of future prototypes with appropriate modifications for risk of migration of the filter.