Bioconvertible inferior vena cava filter could eliminate retrieval and complications


David Rosenthal, clinical professor of Surgery at the Medical College of Georgia, and chief of Vascular Surgery, Atlanta Medical Center, Atlanta, USA, presented data on a novel, bioconvertible vena cava filter at the VEITHsymposium in New York.

The new inferior vena cava filter is intended to offer temporary protection from a pulmonary embolism for a period of time and then become incorporated into the vena cava wall, Rosenthal said.

He noted that currently available permanent inferior vena cava filters are associated with an increased risk of long-term deep vein thrombosis, filter erosion into adjacent structures, and vena cava thrombosis. Retrievable inferior vena cava filters have reported additional problems which include filter tilting, perforation, migration and fracture and they require a second invasive retrieval procedure which has its own inherent risks and costs.

The Novate inferior vena cava filter, from Novate Medical, is a biodegradable and bioconvertible filter. It is designed as a filter with a stent-like support frame. The device stays in its filtering configuration for a minimum of 60 days, offering protection from pulmonary embolism during a patient’s high-risk period and then converts to its non-filtering, stent-like configuration. The filter arms are held in place by a bioabsorbable filament. When the bioabsorbable filament degrades, the filter arms open and retract to the vena cava wall for incorporation. “This unique design allows for temporary inferior vena cava filtration, but avoids the necessity of a second invasive procedure to remove the filter,” Rosenthal explained.

Rosenthal described results from animal studies that support the safety and performance of these filters. Fifteen filters were implanted in sheep. The filters were deployed at the desired location in the infrarenal inferior vena cava via right and left femoral vein approaches. Weekly abdominal X-rays were performed to evaluate the time to opening for each filter. All the filters exceeded the 60 day indicated filtering time.

“At six-month follow-up, vena cavography in 10 sheep demonstrated that the filters were incorporated into the inferior vena cava wall with normal unobstructed blood flow observed. There was no evidence of filter perforation, migration or fracture and at explant no pulmonary emboli were identified at lung necropsy,” Rosenthal said.

A first-in-man feasibility study demonstrated that the device remained in its filtering configuration for a minimum of 60 days. No device-related problems or pulmonary embolism were reported. To evaluate the safety and efficacy of the Novate Filter a multicentre patient trial will commence in the near future to evaluate the deployment system, deployment accuracy, filter-related complications (i.e. migration, fracture, tilting), the occurrence of deep vein thrombosis and/or pulmonary embolism, and the timed “opening” of the filter documented by CT venography and/or abdominal X-ray.

“The Novate inferior vena cava filter is a bioconvertible filter which represents the next generation filter,” Rosenthal concluded.