Vena Cava Filters

Considerable progress has been made in the last decade in understanding the natural history of “treated” venous thromboembolism (VTE). VTE occurs at a rate of 1/1000 in the general population1 and significantly increases with age, especially after age 60, with rates as high as 1/100.2 Duplex ultrasonography has largely replaced venography as the diagnostic test of choice for deep venous thrombosis (DVT),3 and spiral CT pulmonary angiography is rapidly replacing ventilation/perfusion lung scans as the diagnostic test of choice for pulmonary embolism (PE).4 Multiple agents are now available for the initial treatment of VTE including unfractionated heparin, low-molecular-weight heparin, and fondaparinux,5 and although the vitamin K antagonists remain the sole oral agents for the long-term treatment of VTE, new oral alternatives are on the horizon.6 As the result of large randomized controlled trials the secondary prevention of recurrent VTE has improved, with the duration of therapy now based on an understanding of the initial inciting event and the presence of ongoing risk factors.7 Patients with idiopathic DVT or persistent risk factors require anticoagulant therapy for a minimum of 6 months, and more likely, ≥12 months, with a cumulative risk of recurrence as high as 30% at 8 years.8 For patients with cancer and VTE, it has been shown that therapy with low-molecular-weight heparin for the first 3 to 6 months results in better outcomes than the outcomes of patients transitioned to warfarin early in the course of therapy.9 Unfortunately, …