New research suggests that patients with inferior vena cava (IVC) filters are more likely to experience retrieval complications the longer the devices remain in the body. The study, which was published June 12th in Cardiovascular Interventions, indicated that standard retrieval techniques fail more often among patients who have had filters in place longer than 7 months, resulting in the need for more advanced removal procedures.
IVC filters are used in patients who are at risk for a dangerous type of blood clot called pulmonary embolism, but who are unable to use standard blood-thinning medications. The devices are placed in the inferior vena cava, where the small, cage-like structures intercept blood clots before they can travel to the heart and lungs. Retrievable blood clot filters are intended to be removed from the body once patients are out of danger. However, research published by JAMA Internal Medicine in 2013 suggested that just 8.5% of these devices were successfully removed from patients.
Since 2010, the U.S. Food & Drug Administration (FDA) has issued two safety alerts regarding the use of retrievable blood clot filters. The first was released in August 2010, after the devices were linked to hundreds of adverse events, including reports of filters fracturing and migrating to other areas of the body. In other cases, pieces of the filters perforated organs and blood vessels. In May 2014, the FDA issued a second alert to remind doctors of the importance of timely filter retrieval, recommending the devices be removed within 29 to 54 days of their implantation to reduce the risk of patient harm.
Since the FDA acted, thousands of IVC filter lawsuits have been filed in U.S. courts on behalf individuals who allegedly suffered severe and life-threatening complications related to retrievable devices manufactured by C.R. Bard, Inc. and Cook Medical, Inc. Plaintiffs involved in these litigations claim that the companies’ retrievable filters are prone to fracture, migration and other problems that can result in life-threatening complications, and accuse the device makers of failing to warn patients and doctors about these risks.
For this study, researchers at the Northwestern University Feinberg School of Medicine analyzed data from 762 IVC filter retrieval procedures. The devices were successfully retrieved in 82% of patients, while 18% of the procedures failed. However, the failure rate hit nearly 41% if the blood clot filter was left in the patient for seven months or more. Dwell time was the only risk factor for retrieval failure.
“The necessity of advanced techniques to maintain technical success of retrieval increases with dwell time,” the study authors concluded. “Patients with retrievable inferior vena cava filters in place beyond 7 months may benefit from referral to centers with expertise in advanced filter retrieval.”