IVC Filters: How A Dangerous Device Stayed On The Market

In 2013, the Journal of the American Medical Association published an editorial with the provocative title: “How could a medical device be so well accepted without any evidence of efficacy?” IVC filters, the respected medical journal noted, should work. It’s only logical, after all. If you want to catch a traveling blood clot before it reaches the lungs, placing a small wire net in the body’s largest vein should do the trick.

ivc filters

But as the title suggests, there’s never been any empirical evidence showing that IVC filters perform the function they’re being sold for.

How “Untested” Device Made Its Way Into Our Bodies

That’s even more surprising when you consider how prevalent these medical devices have become. In 1979, according to the US Food & Drug Administration, around 2,000 IVC filters were implanted in patients, primarily people at an increased risk of suffering pulmonary embolism. By 2007, 28 years and numerous product redesigns later, nearly 167,000 patients received IVC filters. Demand for the devices was off the charts, increasing by 295% every year.


We started out by suggesting that no studies have looked into whether or not IVC filters actually present any health benefits for patients. That’s not quite true.

IVC Filters Increase Deep Vein Thrombosis Risk

There’s been one study, conducted in France, that looked at 400 patients with deep vein thrombosis, a blood clot in the lower limbs that can eventually pass up to block veins in the lungs. That risk, known as a pulmonary embolism, is what IVC filters are designed to prevent. Half of the 400 patients were outfitted with IVC filters, while the other half were treated solely with “standard anticoagulant treatments” like warfarin. Then the researchers sat back, for eight years, tracking patient progress and recording health outcomes.

To their credit, IVC filters lowered the risk of pulmonary embolism, preventing blood clots from reaching the lungs. In the group without filters, 24 patients suffered from “symptomatic” PE, while only 9 patients with IVC filters did. But the study also produced a counter-intuitive, some would say troubling, result: patients with IVC filters were at an increased risk for developing deep vein thrombosis. In other words, filters appeared to cause one of the conditions they were designed to treat.

30 Years Of Use, Absolutely No Evidence

Adding insult to injury, the French study was performed between 1997 and 2005. That means no member of the medical community began investigating the device’s efficacy until 30 years after the first device to resemble a modern-day IVC filter was used. For all that time, and into the present, the benefit of these devices has remained completely untested. They may be utterly useless.

In the meantime, IVC filter manufacturers were busy cooking up new features for their devices, increasing “benefits” for patients and easing the implantation process for health care professionals. These new designs didn’t just come out of the blue, though. They were spurred by numerous studies that found serious long-term consequences, and little benefit, associated with IVC filters designed for permanent implantation.

In a 1973 study, IVC filters were found to reduce the rate of pulmonary embolism, but had no effect on ultimate mortality rates. Besides the French study discussed earlier, this paper written in 1973 is the only clinical trial to assess the effectiveness of IVC filters against an “established alternative,” according to Dr. Judith Walsh, a professor at the University of California San Francisco.

FDA Takes On Retrievable IVC Filters

In 2011, the FDA asked Dr. Walsh, a member of the California Technology Assessment Forum, to review the evidence for and against using IVC filters. Her work, however, was hampered by the shocking lack of medical research on the devices. Two things she could say with certainty? IVC filters don’t seem to improve “net health outcomes” (like survival rates) for patients. They don’t appear to be as beneficial as existing alternatives, like the industry standard anticoagulants, either.

Walsh’s review came on the heels of an FDA Safety Communication, released to the public and medical community on August 9, 2010. A new generation of “retrievable” IVC filters, designed to overcome many of the problems observed with permanent IVC filters, had been approved 4 years earlier. These devices were outfitted with small hooks or “snares,” and could be pulled out using a catheter after implantation.

But the trick with these filters is that they must be removed, preferably as soon as a patient’s risk of pulmonary embolism has subsided. On the basis of 921 adverse event reports, the FDA surmised that many doctors were leaving filters inside patients, long after their (questionable) effectiveness had disappeared. IVC filters, the agency learned, were breaking apart inside patients, sending shards of metal into the blood stream and perforating vital organs. Entire devices were migrating from the site of implantation and blocking the pulmonary vein that leads straight to the lungs.

Patients Suffer, But There’s Still No Answer

There’s little evidence that this problem has improved for patients, although IVC filters remain a main-stay for many physicians. In 2014, the Food & Drug Administration released an update to its Safety Communication, reiterating the dangers of leaving IVC filters in patients for too long, and summarizing several safety studies that are on-going. On the basis of mathematical models, the agency suggested that doctors consider removing filters between 29 and 54 days after they are implanted. Beyond those guidelines, the FDA had nothing more to say and took no regulatory action.

In its 2013 editorial, the Journal for the American Medical Association framed the “history of the IVC filter” as a “valuable insight into the shortcomings of medical device approval in the United States.” Placing blame squarely on the shoulders of the FDA is not entirely unwarranted. The agency approved IVC filters with no clinical evidence of their efficacy, and waited 4 years before telling physicians how long they should leave the devices inside patients. But critics have turned their attention elsewhere, to the manufacturers of IVC filters, companies like Cook Medical and C.R. Bard.

A growing body of evidence suggests that these companies have been actively concealing the dangers of IVC filters for years.

Do Manufacturers Bear Responsibility For Harm?

C.R. Bard and Cook Medical are America’s largest manufacturers of IVC filters. Together, they make seven different models, including several that have been withdrawn from the market over safety concerns.

In 2005, Bard stopped selling its Recovery filter after a study in the Journal of Vascular & Interventional Radiology found that up to 40% of the devices would fracture inside patients within 5.5 years. The company went back to the drawing board, eventually releasing an updated model called the Bard G2. But the G2 still breaks in up to 12% of patients, according to researchers at Penn State.

For all the talk of promoting patient safety, the company only appears interested in making minor tweaks to a device many critics say is defective in design. In their minds, it’s the very concept of an IVC filter that’s broken.

Bard Cited For Multiple FDA Violations

Beyond facing marked criticism for selling a medical device without any evidence to support its use, C.R. Bard has even been hit by formal warnings from the FDA. On July 13, 2015, an FDA official from Los Angeles sent Bard’s CEO, Timothy Ring, a warning letter, citing eight different violations of FDA requirements. From improper manufacturing processes and inadequate quality assurance procedures, Bard’s violations run the gamut. But two citations were particularly damning:

  1. The company had been manufacturing and marketing two IVC models that were never cleared for sale by the FDA.
  2. C.R. Bard had failed to report serious complications to the FDA, including cases of serious injury. Other reports involving injury, which Bard did submit, were incorrectly classified as “device malfunctions” but made no mention of the patient’s injuries.

Now, C.R. Bard and Cook Medical are facing civil lawsuits as well. Lots of them.

Hundreds Of IVC Filter Lawsuits Filed

To date, more than 200 personal injury lawsuits have been filed against Cook Medical, by patients who say the companies Gunther Tulip and Celect filters caused them serious injury. Consolidated in the US District Court for the Southern District of Indiana, the claims allege Cook marketed a medical device that was defective in design, while misrepresenting its efficacy and failing to warn the public of risks.

More than 22 lawsuits against C.R. Bard were given the same treatment on August 17, 2015 and transferred to the US District Court of Arizona. As part of a Multi-District Litigation, the cases will go through pre-trial proceedings together, allowing plaintiffs to share resources and evidence. To date, over 70 lawsuits have been brought against Bard, involving injuries allegedly caused by the company’s Recovery, G2 and G2 Express filters.

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