Are Inferior Vena Cava Filters Effective?

Baton Rouge, LAThe number of lawsuits consolidated for pretrial proceedings in two MDLs continues to grow, with plaintiffs alleging their health was put in jeopardy by IVC filters that broke, fractured or otherwise failed. Meanwhile, researchers asked in an article how IVC filters could have been approved for use with so little evidence of their effectiveness.

The article appeared in JAMA Internal Medicine (2013) and argues that the effectiveness of IVC filters has not been proven in empirical studies. Researchers note that they know of only one randomized controlled trial of the IVC filter. That trial (PREPIC) found that after two years, there was no difference in the mortality rates of patients who received a permanent filter compared with those who did not receive a filter. But, they did find a higher rate of deep vein thrombosis in patients who received the filter. By eight years, patients who received the filter had lower risk of pulmonary embolism, but higher risk of deep vein thrombosis. Mortality between the two groups was similar.

IVC (inferior vena cava) filters are implanted in patients who cannot use anticoagulants or other therapies to prevent blood clots and pulmonary embolisms. The filters are implanted so that the legs of the filter can trap blood clots, preventing them from traveling to the patient’s lungs where they could cause a pulmonary embolism.

While the filters perform an important duty, lawsuits allege some filters have a higher risk of fracturing. When that happens, portions of the filters can break free and migrate to other organs, perforate veins, or cause other internal and potentially life-threatening damage. The risks are high enough that researchers writing for JACC Cardiovascular Interventions (4/16) wrote that without a congenital anomaly, unretrieved IVC filters are the most common cause of IVC thrombosis.

The study’s authors were concerned that filters are being retrieved too infrequently, putting patients at risk for developing IVC thrombosis. Although IVC thrombosis is rare, it can be deadly.

IVC filters come in permanent and retrievable forms. The permanent form is used in patients who have a long-term risk of blood clots. The retrievable form is for patients who are at risk of a blood clot over the short-term, linked, for example, to a car accident, surgery or certain treatments. In such cases, the FDA recommends removing the filter between 29 and 54 days of implantation if the risk/benefit profile favors removal of the device.

As of April 15, 2016, there were 382 lawsuits consolidated in MDL 2641 against Bard, up from 93 in March. There were also 343 consolidated in MDL 2570 against Cook Medical, up from 289 in March. Those lawsuits allege the IVC filters had a risk of breaking or otherwise failing early, causing significant health risks when they did.