IVC filter use is on the decline in the United States—but not nearly enough, according to several prominent voices in the field of internal medicine. They are calling for a temporary prohibition or severe restriction on the use of inferior vena cava (IVC) filters, citing evidence that the medical devices have not been shown to be safe or effective and that they pose serious risks to health.
IVC filters are placed in the inferior vena cava, a large vein that carries blood from the lower body back to the heart. They are meant to catch blood clots and prevent them from traveling to the lungs and causing a pulmonary embolism. But the filters have a history of fracturing, breaking loose and migrating to the heart, or puncturing the IVC and damaging surrounding organs. The consequences have sometimes been fatal. Patients have filed thousands of IVC filter lawsuits, charging filter manufacturers with negligence and failure to warn consumers of the dangers of IVC filter placement.
Recently, Rita Redberg, MD, editor of the prestigious journal, JAMA Internal Medicine, called for a moratorium on IVC filters, “unless or until there are data showing efficacy greater than risk.” Her editorial appeared in the September 2017 issue of the journal. In that same issue, doctors at Temple University Hospital in Philadelphia, PA, and the Mayo Clinic in Rochester, MN, reported on their research into IVC filter use. While they did not call for a ban, they expressed the view that the filters are being used much too frequently.
IVC Filter Use in Decline
The Temple University research team was led by Riyaz Bashin, Professor of Medicine at Temple’s Lewis Katz School of Medicine and Director of Vascular and Endovascular Medicine at Temple University Hospital.
The researchers studied trends in IVC filter use between January 2005 and December 2014, with a particular interest in what happened after 2010. That was the year the U.S. Food and Drug Administration (FDA) warned physicians about adverse events linked to the filters, including device migration, filter fracture, and perforation of the inferior vena cava by the filter. The agency advised physicians to remove retrievable IVC filters as soon as patients no longer needed protection from a pulmonary embolism.
The warning did appear to have some effect. The Temple University researchers found that after climbing for five years, IVC filter use began to decline in 2010. The rate of IVC filter placement decreased from 55 placements per 100,000 U.S. population in 2010, to 39 placements per 100,000 in 2014. This occurred even though the rate of hospitalizations for venous thromboembolism (the formation of a blood clot in a vein) was essentially unchanged during this period.
That decline, however, was not enough for the Temple University doctors. Use in the United States, they wrote, is 25 times higher than in Europe. Due to the short and long-term consequences of IVC filter implantation, they recommended that IVC filter placement be reduced to a rate “similar to or lower than the rate observed in Europe.” That would be less than three per 100,000 population, as opposed to the 2014 rate of 39 placements per 100,000.
A December 2017 study, also published in JAMA Internal Medicine, confirmed the findings of the Temple University group and added an additional layer of analysis that included the medical reasons for the filter placement—deep vein thrombosis [DVT], pulmonary embolism [PE], or prophylactic use in patients with neither condition. The study was conducted by researchers at the Washington University School of Medicine, led by David L. Brown, Professor of Medicine, and a Fellow of the American College of Cardiology.
The researchers analyzed national hospital discharge data between 2005 and 2014 and found that IVC filter use increased from 2005 to 2010 but then began decreasing, from 412 filter placements per 100,000 hospital discharges in 2010 to 322 placements in 2014.
Dr. Brown also investigated rates of IVC filter placement in cases where anticoagulant medication could not be used due to a medical condition such as hemophilia, pericardial disease, or recent surgery. He found that filter placements decreased both in patients where anticoagulation medication was contraindicated (could not be used) as well as in patients for which there was no contraindication for anticoagulants.
No Evidence of IVC Filter Efficacy
Dr. Redberg and the researchers involved in the two studies all pointed to a lack of evidence for the effectiveness and safety of IVC devices in the medical literature. Dr. Redberg remarked that at the time of the FDA’s 2010 warning, she had observed that the agency placed IVC filters in the same risk category as mercury thermometers and approved the devices with no clinical evidence (evidence from testing on human subjects) of safety and effectiveness. Her views were echoed in a 2013 article published in JAMA Internal Medicine, written by three doctors from the National Cancer Institute, Northwestern University, and the University of Chicago Department of Medicine, respectively. They titled their paper, “The Inferior Vena Cava Filter – How Could a Medical Device Be So Well Accepted Without Any Evidence of Efficacy?”
The Temple University Hospital doctors wrote that the effectiveness of IVC filters in reducing morbidity and mortality associated with venous thromboembolism (blood clots in the veins) “is uncertain.”
The Washington University scientists made several significant observations about IVC filter efficacy. They wrote that their own finding that IVC filter use varied widely by U.S. geographic region “is consistent with a lack of evidence supporting the use of IVC filters.” In California, Oregon, and Washington, for example, IVC placement rates averaged 251 per 100,000 hospital discharges, whereas in New York, Pennsylvania, and New Jersey the rate was 387, 54% higher. Citing a 2005 study, they stated that IVC filters can reduce the risk of a pulmonary embolism, but they increase the risk of deep vein thrombosis and have no positive effect on survival. Finally, they repeated what Dr. Redberg had stated back in 2010—evidence from well-designed research involving human subjects is lacking. To their knowledge, they said, there have been no well-designed studies involving patients with a contraindication for anticoagulant medication and none that investigated prophylactic filter use in patients without DVT or PE.
These findings point to a troubling breakdown in the systems designed to keep patients safe. There appears to be a broad consensus that evidence for the safety and effectiveness of IVC devices is lacking. Indeed, by 2014 the FDA had put the risk/benefit ratio for the devices in very concrete terms, stating that somewhere between 29 and 54 days after filter placement, the risks begin to outweigh the benefits in patients for whom the “transient risk for pulmonary embolism has passed.”
Today the discussion continues in medical journals. But now the legal system is called upon to intervene where the medical system has failed to protect consumers.