The Food & Drug Administration is recommending that physicians consider removing retrievable inferior vena cava filters after logging 921 reports of "adverse events" related to the devices.
The federal watchdog agency warned that certain IVC filters could fracture, causing pieces of the device to travel through the bloodstream to other parts of the body.
Doctors place the device in the inferior vena cava, the main vein that brings blood back to the heart from the lower half of the body, to keep blood clots from traveling to the lungs and causing pulmonary embolisms. The implant treats patients with venous thromboembolism who have not responded to or cannot take anti-clotting medications.
There are two types of IVC filters, a permanent implant and a "retrievable" device meant for temporary use. The FDA said many of the 921 events reported appeared to be related to "a retrievable filter remaining in the body for long periods of time, beyond the time when the risk of [PE] has subsided." The reports involved device movement within the body, detachment of device parts, filter fracture and perforation of the IVC. The agency said doctors should remove the filter once the risk of pulmonary embolism has passed.
The filters are made by 10 companies, including units of New Jersey-based C.R. Bard Inc. (NYSE:BCR) and Johnson & Johnson (NYSE:JNJ); Vancouver, B.C.-based Angiotech Pharmaceuticals Inc. (NSDQ:ANPI); and Conshohocken, Pa.-based Rex Medical LP. The FDA did not specify the number of adverse event reports per manufacturer.
A separate article published online Monday in the Archives of Internal Medicine found problems associated with two types of filter made by C.R. Bard. Doctors commenced the study that the article is based on after a patient suffered a perforation of the heart three years after receiving an IVC device.
The study looked at 80 patients who received either of the two devices between April 2004 and January 2009. Of 28 patients who received the Bard Recovery filter, the older of the two models, 25 percent experienced a fracture. Twelve percent of the patients who received the Bard G2 filter, the model which replaced the Recovery filter to reduce the risk of fracture, experienced a fractured device. The patients implanted with the Recovery filter had the device inside them for twice as long.
The FDA said about 167,000 filters were implanted in 2007, with projections of 259,000 implantations by 2012.
According to a post at MedGadget.com, doctors may decide to leave the retrievable filters in place in certain patients for whom the risk of pulmonary embolism never abates.
“While it’s nice to know the risks and attach numbers to the different kinds of (sometimes spectacular) device failures, our sense of the matter is IVC filters aren’t placed on just anybody. These are patients that have failed medical management of [deep vein thrombosis], have clotting disorders, or both. For many of these patients, the risk for PE will never ‘subside’ so IVC removal isn’t an appealing prospect. If the FDA (or some specialty society) could give guidelines as to how frequently these filters should be replaced, well, we’d be happy to report that good news,” according to the website.