Retrievable inferior vena cava (IVC) filters are small cage-like devices placed in the inferior vena cava, the large vein carrying deoxygenated blood to the heart. They are designed to capture blood clots traveling from the deep veins of the legs before they each the heart or lungs. The Food and Drug Administration (FDA) recommends that these devices be removed when they are no longer needed.
But according to a new analysis, the longer they are in they are left inside patients, the riskier the retrieval becomes. The study found that IVC filters with a “dwell time” inside the body of more than seven months have a failure rate of more than 40 percent.
“The message is that if you have a patient who’s had a filter in for seven months or longer, really consider that they may need more than a standard technique and consider referral for advanced retrieval,” said Kush R. Desai, MD, the study lead author, in an interview with TCTMD. Desai is with Northwestern University Feinberg School of Medicine in Chicago.
IVC filters were cleared by the FDA to remain in patients permanently. But in 2010, the agency issued a Safety Communication informing doctors that the devices were associated with serious adverse events. Reports included cases of the device migrating or fracturing causing embolization, lower limb deep vein thrombosis, and IVC occlusion. Due to the growing list of adverse events, the FDA recommended that IVC filters be removed when possible.
The number of adverse event reports related to prolonged dwell times is not known. But in a quantitative analysis published in the Journal of Vascular Surgery: Venous and Lymphatic Disorders, FDA researchers that the best outcomes with IVC filters were seen when the devices were removed between 29 and 54 days after implantation.
Based on the recent analysis, Desai and colleagues said that doctors should maintain close follow-up with their patients implanted with IVC filters and to act on their removal in a timely manner.