Early iterations of the IVC filter were primarily designed as a permanent hedge against blood clots for those patients unable to tolerate blood thinners, or for whom anti-coagulants proved ineffective. The inferior vena cava filter is a spider-like device with struts that is placed in the inferior vena cava – the major artery that returns deoxygenated blood from the lower extremities to the heart and lungs. Blood clots often form in the legs due, in part to age and inactivity. Were blood clots to migrate up to the lungs, a dangerous and potentially fatal health event could ensue.
Anti-coagulants (blood thinners) are routinely prescribed as Americans age as a hedge against the development of blood clots. The subsequent development of the IVC filter, placed into the inferior vena cava as something akin to a catcher’s mitt, served as another spanner in a physician’s tool kit aimed at reducing the risk for blood clot migration by entrapping a clot in the spider-like appendages of the IVC filter.
Since those early days, the landscape has changed. Early filters designed to be permanent have proven problematic for some patients the longer they are left in the body. To that end, the longer an IVC filter remains in place, the more difficult the task to extract the filter due to the filter becoming more deeply embedded, with time, in tissue.
The second and most significant development has been the advent of the retrievable IVC filter, specifically designed for use as a temporary hedge against blood clot when blood clot risk is at its highest, and in patients for whom blood thinners are insufficient to stem the risk.
There have been accusations that retrievable IVC filters are less robust than their permanent counterparts, and are prone to fracture. Indeed, a plethora of IVC filter lawsuits allege failure of the IVC filter either through the fracture of struts which migrate through the bloodstream to vital internal organs, or the migration of the IVC filter itself to the heart and lungs.
It has been reported that the US Food and Drug Administration (FDA), the federal regulator responsible for the drug and medical device industry, has received over time a minimum of 900 reports of problems filed with the FDA’s Adverse Events Reporting System (AERS) – most involving device fracture, failure or migration. In response the FDA, in May of 2014, determined that the risk for adverse events associated with the inferior vena cava filter increases the longer a device is left in place. A statement indicated IVC filters should be removed as soon as the danger for blood clot has passed, with the recommended removal window described as 29, to 54 days following initial implantation.
A study published the following April in JAMA appeared to verify the FDA’s concern: that IVC filters were not as effective in preventing blood clots as anti-coagulants, with IVC filter patients twice as likely to suffer blood clot migration to the lung, as those on blood thinners.
In deference to the FDA’s assertion that IVC filter complications increase the longer a retrievable filter is left in place, various reports suggest that in the majority of cases retrievable filters are not retrieved, and certainly not within the window of removal recommended by the FDA. Industry watchers and healthcare advocates cite various reasons for this, including doctors who were not aware of the importance of retrieval, or IVC filter placement conducted as an emergency while the patient was travelling, for example, without adequate follow-up once the patient returned home.
In many cases, an attempt to retrieve an IVC filter has failed due to the device becoming embedded in tissue, or having migrated so close to vital organs, retrieval is deemed too great a risk.
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One of those competing manufacturers is C.R. Bard, makers of the Bard IVC filter. The Bard Recovery filter was introduced in 2003 but was soon shown to be failure-prone. The Bard G2 IVC filter was introduced some years later as a replacement for the Recovery filter (an IVC filter recall for the Recovery filter was never officially undertaken) boasting various enhancements and improvements with reduced tendency to fracture.
Plaintiffs tied to many an IVC filter lawsuit, however, claim the Bard G2 filter is no better than the Recovery filter it was meant to replace, with both having presented equally high rates of failure.