Since that time a number of additional products from manufacturers such as C.R. Bard (Bard) and Cook Medical (Cook) have appeared on the market, all designed for insertion into the inferior vena cava – the largest artery in the human body, which functions as the primary conduit to bring de-oxygenated blood up from the lower extremities to the heart, and lungs to be re-oxygenated. A blood clot from the lower extremities travelling up the inferior vena cava can have deadly consequences.
Middle-aged and older individuals are more susceptible. Susan Karnstedt was, at 24, in the minority. As it turned out, the insertion of an IVC filter succeeded in saving her life.
But there were problems later, as patients having received the first permanent IVC filters and later patients having received the more recent temporary, or retrievable IVC filters, have discovered.
In Karnstedt’s case, all was fine for a time. But then, according to a story posted at Stanford Health Care (01/12/11) she began experiencing intermittent pain in her abdomen. She chalked it up to her diet, or her active lifestyle. But the pain continued.
It was later determined that the filter had begun to impact her intestine. “Over time, a few of the filter legs had eroded through, perforating her IVC, and one of them had impaled her intestines,” said Dr. William Kuo, an interventional radiologist at Stanford Hospital and Clinics who has developed a method for extracting troublesome IVC filters. “The filter tip had also become tilted and was embedded within the IVC wall. The degree of filter leg penetration through the intestines was shocking and undoubtedly the cause of her chronic and worsening abdominal pain.” Karnstedt described it as a “fork poking” into her intestines.
The IVC filter, one of the original ‘permanent’ filters, had been in place for some 18 years. Kuo managed to remove it. Since then, there has been a litany of litigation as well as dialogue about the dangers of leaving even permanent filters in place too long, together with the newer breed of temporary filters designed to be inserted, then removed once the danger of a blood clot has passed.
The US Food and Drug Administration (FDA), in analyzing data collected by its Adverse Events Reporting System, recommends that IVC filters be removed immediately once the danger of blood clot has passed, and should not be left in place longer than about six weeks.
However some patients, such as those with a Bard G2 IVC filter, have seen their filters languish in their bodies far longer. The reasons can be varied: a patient may be fitted with an IVC filter as part of a temporary response to a blood clot by a surgeon in a different city, should a patient be travelling, for example. Then, the information doesn’t make it back to the individual’s primary care physician.
In other cases, attempts to remove an IVC filter have failed. A study published in 2013 in the Journal of the American Medical Association (JAMA) found that, on average, 18.3 percent of attempts to remove IVC filters failed. Those patients are left to deal with the presence of an IVC filter – permanent or temporary – for the rest of their lives, along with the reliance upon blood thinners to ward against blood clots and blockages at the insertion site for the IVC filter in the inferior vena cava.
That’s a Catch 22 for some patients, who are outfitted with an inferior vena cava filter due to problems tolerating blood thinners.
There are allegations that temporary, retrievable filters were founded upon the more robust design of the permanent version, only to evolve to a weaker, less-robust version to aid in removal. Were all temporary filters, such as the Bard G2 IVC filter, to be successfully removed within the recommended FDA time frames, the situation would be less serious than it is. However, with temporary IVC filters left in place too long – or in some cases, not retrievable – the risk for a catastrophic health event from device migration or injury from a broken strut increases exponentially.
“There are two types of filters,” says Kuo, in a video accompanying the Stanford Health story. “The original, permanent filters and retrievable devices that are now on the market – and both of these types can actually end up becoming permanent implants.
READ MORE IVC FILTER LEGAL NEWS
Plaintiffs bringing an IVC filter lawsuit allege manufacturers such as Cook Medical and C.R. Bard were negligent in bringing unsafe products to the market, and leaving them there. The Bard G2 IVC filter was brought to the market in 2005 as the successor to the allegedly troubled Bard Recovery filter, its first-generation retrievable product that was found to have a 25 percent rate of failure. The Bard G2 filter was found to have a 12 percent rate of failure, but was also criticized as not being much better than the IVC filter it succeeded.
One study found that all C.R. Bard filters combined to a 12 percent rate of failure.