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

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.

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.

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.

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.