Abstract:

BACKGROUND: Permanent vena cava filter as a long-term foreign body into the body may cause multiple complications, such as filter migration, perforation inferior vena cava (IVC), local thrombosis, and IVC occlusion,etc.
OBJECTIVE: To design and fabricate a biodegradable filter.
METHODS: A biodegradable filter was designed with a special center-thread expanding mechanism. Two-strut and five-strut biodegradable filter models were fabricated by using biodegradable polymer Poly (L- Lactide) Acid (PLLA), on which mechanical tests were performed, and in vitro degradation and clot-trapping experiments were conducted.
RESULTS AND CONCLUSION: The experimental results showed the center-thread not only expands the filter, but also enhances its radial stiffness. The biodegradable PLLA filter has similar mechanical property and clot-trapping ability as conventional metal filters. The major problem of the biodegradable filter lies in the debris, which may generate and detach from the filter during the degradation process. By incorporating a thin thread into the PLLA struts, the debris size is reduced to about  2 mm. Although the small debris is not likely to block the trunk or large branches of pulmonary arteries, its impact on human body is still unknown. Therefore, biodegradable filter has the potentials for clinical application and deserves further study.