To date, there has been only one randomized controlled trial completed on IVC filters. This study found that IVC filters reduced the incidence of PE but increased the incidence of deep vein thrombosis (DVT). All patients were on anticoagulation drugs during the study. Results from the PREPIC study and other studies which have shown many long-term complications of IVC filters led to the introduction of retrievable IVC filters. The first retrievable IVC filters were approved by FDA in 2003 and 2004.