Inferior vena cava filters.

Venous thromboembolism is common. Most pulmonary emboli arise as thromboses in the deep veins of the lower extremities and may result in serious complications. Inferior vena cava filters (IVCF) are intended to prevent the passage of deep vein thrombosis to the pulmonary arteries. Accepted indications for IVCF placement include the presence of acute venous thromboembolism with inability to administer anticoagulation medication or failure of anticoagulation. Despite these clear indications, IVCF have been commonly placed in patients for primary prevention of pulmonary emboli in patients deemed to be at high risk, along with several other "soft" indications. As a result, IVCF use has been rising over the past 2 decades, especially given the retrievable nature of modern devices. Nonetheless, IVCF are not free of complications, which may occur during implantation and retrieval and while retained in the body. Despite this increase in use, the long-term efficacy remains unclear, and the management of patients with retained filters is often controversial. Finally, filter retrieval in eligible patients is relatively infrequent, suggesting that systems must be in place to improve appropriate filter use and to increase retrieval.