Inferior vena cava (IVC) filters are umbrella-shaped devices that are implanted into a patient’s inferior vena cava, a major vein carrying blood from the lower part of the body to the heart. They are used when patients are at risk for a pulmonary embolism, a potentially life-threatening condition where a piece of a blood clot can break off from elsewhere, such as the leg (deep vein thrombosis), and travel to the lungs. IVC filters are meant to stop a blood clot before it reaches the heart and lungs. Some are retrievable.
Baylor University Medical Center Proceedings recently published a case report of one woman who was implanted with the Bard G2 IVC filter; it remained for six years before it was retrieved. A CT scan showed that two of the struts had fractured and the filter was tilted more than 15 degrees out of position. The fractured struts had punctured the IVC in multiple locations. The authors write that an IVC filter can migrate when there is a foreshortening and flattening of the IVC and this motion gets transferred to the filter. They state that although IVC removal is has a high rate of success in the first year and is generally considered safe, allowing the device to remain for long periods of time can increase the risk of complications.
Potential complications associated with retrievable IVC filters, according the authors, include: perforation (0%–41%), filter migration (0%–18%), filter fracture (2%–10%), and IVC occlusion (2%–30%), the study states. The authors note that “Caval perforation can result in injury to adjacent structures, although most are asymptomatic. Extreme examples include gastrointestinal hemorrhage and aortic dissection. Migration of fracture fragments can cause serious complications, such as life-threatening arrhythmias and myocardial perforation with cardiac tamponade.”
In 2010, the U.S. Food and Drug Administration (FDA) advised health care professionals to remove IVC filters when the threat of pulmonary embolism was longer present. The agency issued another alert in 2014 advising doctors to remove the IVC filters approximately one to two months after the patient is no longer at risk for a pulmonary embolism. The alert was issued because the risk of complications appeared to be greater the longer the device is left in place.
Lawsuits filed against IVC filter manufacturers allege that the devices fractured, migrated, tilted and perforated. Court records indicate that 1,500 such cases have been filed, with plaintiffs alleging that device makers failed to warn about these risks. The suits also allege that doctors were not adequately warned about the increased risk of complications when IVC filters are retrieved after longer periods of time.
Device makers such as C.R. Bard, Cook and Cordis are facing lawsuits over IVC filters. More than 700 lawsuits are consolidated in a Bard IVC Filter multidistrict litigation in Arizona. Additionally, more than 650 cases are pending against Cook Medical in Indiana and 100 have been filed against Cordis in California state court.