Inferior vena cava (IVC) filters are devices used to prevent pulmonary embolism, an often fatal condition where a blood clot detaches from a large vein in the leg and becomes lodged in the lungs. IVC filters are put into place in the largest vein in the body, the vena cava, to catch the blood clot and prevent it from reaching the lungs or heart. They are used when people are unable to safely use blood thinning medications.
Many IVC filters are made to be permanent, but more modern designs are intended to be temporary. But, according to national data, the temporary, or retrievable IVC filters are often left in permanently, increasing the patient’s risk for the device to tilt, migrate, perforate or fracture. Despite the lack of clinical studies to prove the safety and efficacy of the filters, their use continues to rise year after year.
Researchers from Boston University School of Medicine (BUSM) have known for years that the use of IVC filters may not be such a great idea, due to the high failure rate and low retrieval rates. A study was conducted at Boston Medical Center (BMC), New England’s largest trauma center, in 2010. Researchers advised since most IVC filters are designed to be temporary, the device should be removed as soon as the risk of pulmonary embolism has resolved.
The study reviewed IVC filter use between August 2003 and February 2011 at BMC for a total of 978 patients. Of the 679 retrievable IVC filters, 91.5 percent of them could not be successfully removed. Unsuccessful attempts at retrieving the filters were made in 18 percent of patients, and nearly 8 percent of patients still experienced VTE’s (venous thromboembolism), and 25 pulmonary emboli occurred, all while the filter was in place.
Although the IVC filters were placed due to perceived inability to tolerate anticoagulation medication, 25 percent of the patients were discharged on therapeutic anticoagulation.
Due to the high failure rate of temporary IVC filters, the device manufacturers such as Rex Medical, C.R. Bard, Johnson & Johnson’s subsidiary Cordis, and Cook Medical have been facing a large number of lawsuits for injuries and deaths linked to the filters.