It was on April 8, 2013 that JAMA Internal Medicine (JAMA) published Indications, Complications, and Management of Inferior Vena Cava Filters: The Experience in 952 Patients at an Academic Hospital with a Level I Trauma Center.
The study authors concluded that a low retrieval rate combined with other factors, resulted in less-than-optimal outcomes “due to high rates of venous thromboembolism (VTE).”
In other words, retrievable IVC filters are not all they’re cracked up to be. What’s more, legal professionals involved in discovery ahead of bellwether trials note that problems with permanent IVC filters were few. Apparent design flaws with retrievable filters, however, appear to be exacerbating the problem. Further complicating things is the fact that IVC filters designed to be retrieved are not retrieved at all in the majority of cases.
The IVC filter is so named after the inferior vena cava, a primary artery. Patients who do not tolerate blood thinners and are at risk for stroke will often have an IVC filter implanted in the inferior vena cava to “catch” a meandering blood clot before it can migrate to the lung. As suggested earlier, the permanent version of the inferior vena cava filter appeared to have few issues.
It is the retrievable version that appears to be experiencing a myriad of problems, according to the JAMA-published study that proves enlightening.
For example, IVC filter usage - including the Bard IVC filter - continues to increase in spite of a lack of randomized, controlled trials. What’s more, guidelines governing their insertion are not unified. “The American College of Radiology and Society of Interventional Radiology guidelines state that a filter can be placed as prophylaxis for any patient at high risk of developing a DVT or PE,” state the study authors, “while the American College of Chest Physicians guidelines recommend against an IVC filter unless the patient has an acute proximal lower extremity DVT and cannot tolerate anticoagulants. These conflicting guidelines reflect the absence of good-quality data to guide clinical practice.”
Another issue is the retrievabilty of filters designed and approved to be retrieved. The US Food and Drug Administration (FDA) is among medical authorities that post guidelines on the retrieval timelines of retrievable filters. All agree that IVC filters should be retrieved when the danger of blood clot passes - however, the real-world success rate of retrieval is dreadful.
The JAMA-published study references an attempt to remove only 10.5 percent of the IVC filters. That translates to an 89.5 percent rate of retrievals that were not even attempted. Of those attempted, only 58 retrievals out of 679 were successful (8.5 percent). Another 13 retrievals were attempted but failed, for various reasons.
Those failures included: “Filter embedded in the IVC, filter protruding through a blood vessel, abnormal filter position, or a clot within the filter. One patient had more than one reason for retrieval failure, including a clot in the filter, and protrusion from the IVC.”
The study had more to say: “An important consideration when placing a filter is the risk of complications, not only during placement and retrieval but also long-term consequences if left in place. At least 10 serious complications were noted in this review. This is likely an underestimate of the total mechanical complications because minor mechanical issues were not systematically noted in this data set. Most of the filters in this review were designed for retrieval, yet only 8.5 percent were successfully removed. Therefore, approximately 91.5 percent of retrievable filters placed in patients at risk for VTE became permanent filters.”
They were not designed to be permanent filters. As indicated earlier, permanent IVC filters presented with few issues. In contrast, retrievable filters have been associated with an escalating series of problems, or so it has been alleged in IVC filter recall lawsuits.
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The risk of failure only increases the longer an IVC filter designed to be retrieved is left in place. In kind, a retrievable filter that winds up as a permanent fixture translates to limitless risk.
Many IVC retrievable filters, including the Bard G2 IVC filter, are the subjects of IVC filter lawsuits. Plaintiffs allege that filter manufacturers knew of the problems inherent to their products, but kept mum.
The study authors conclude, in part: “Our research suggests that the frequent use of IVC filters for VTE treatment and prophylaxis, combined with a low retrieval rate and inconsistent use of anticoagulant therapy, results in suboptimal outcomes, such as mechanical filter failure and high rates of VTE.”