By: Staff Writers | Published: August 10th, 2010
After receiving more than 900 reports of problems with IVC filters over the last five years, federal regulators are warning doctors to remove the filters, which are meant to prevent pulmonary embolisms, before they can break free inside the patient and do damage.
The FDA issued a safety alert this week for inferior vena cava (IVC) filters. The IVC filters are placed inside patients to prevent blood clots from breaking free and traveling to the lungs or heart and causing a pulmonary embolism. However, the FDA is telling doctors they should remove the filters once the danger of the clot has passed, or else the filters could break free and travel through the body of the patient.
The FDA warning notes that the agency has received 921 adverse event reports involving problems with IVC filters implanted. Of those, 328 involved the filter breaking free and migrating through the body, 146 involved components breaking loose, 70 involved the IVC being perforated and 56 reports were of the filters fracturing. While the agency did not detail the types of injuries resulting due to the side effects of IVC filter failure, it did note that some of the events led to “adverse clinical outcomes” for the patients.
The agency’s recommendations are that physicians remove the filters, which are designed to be retrievable, once the threat of pulmonary embolism has passed. The FDA warning said that all physicians are encouraged to consider the benefits and health risks of IVC filter removal for each patient.
A pulmonary embolism can occur when blood clots travel through the blood stream and becomes lodged near the lung. This can cause a sudden blockage of the artery that brings blood into the lungs, causing serious and potentially fatal injuries.
In conjunction with the FDA warning, a clinical study was published online by the Archives of Internal Medicine that highlights the high failure rate of C.R. Bard’s Bard Recovery and Bard G2 IVC filters. An editorial accompanying the article says the problem with the Bard IVC filters highlights the failures of the FDA’s 510(k) premarket approval system, which has come under heavy fire in the last year.
Researchers found that the Bard IVC filter problems appear to be both commonplace and severe, with sometimes deadly results. The clinical trial involved 80 patients who received either the Bard Recovery or the Bard G2 filters. Of those, 13 of the patients had at least one strut that was part of the IVC filter fail.
The Bard Recovery, the older of the two filter designs, was the worst, with a failure rate of 25%. Of the seven out of 28 Bard Recovery filters that failed, five of them (71%) resulted in a piece of the filter traveling to the patient’s heart. Three patients experienced life-threatening complications, and one of them died as a result.
The Bard G2 filters had a failure rate of about 12%, with six of the 52 implants fracturing. In two cases, parts of the filters broke off and traveled through the patient’s body.
Researchers pointed out that addressing the problems of failed filters could require open-heart surgery. They also noted that the patients receiving the filters generally have a much higher mortality rate than the average population, making them even more vulnerable to IVC filter problems. They also said they suspect the failure rates would have been higher if the filters would have been left in longer.
The editorial, by Dr. Rita F. Redberg, an editor with the medical journal, points out that both of the Bard IVC filters involved in the study were approved using the expedited 510(k) approval process, which only requires that a medical device be substantially equivalent to a device already on the market for approval. The filters were categorized as Class II medical devices, the same classification as mercury thermometers, and were approved without any clinical data of safety and effectiveness.
The editorial comes as FDA officials and lawmakers are considering ways to strengthen the FDA’s control of medical devices and close some of the loopholes in the 510(k) premarket approval process.