The Role of Inferior Vena Cava Filters in Pulmonary Embolism.

Pulmonary embolism (PE) is a cause of significant morbidity and mortality, with an estimated 600,000 cases of clinically significant PE in the United States annually, and roughly 200,000 deaths per annum directly attributable to PE. By far the most frequent cause of PE is deep vein thrombosis originating in the lower extremities, which travels to the pulmonary vasculature. The mainstay of treatment is anticoagulation, but multiple additional treatments exist for patients in whom anticoagulation is inadequate or contraindicated. The absolute indications for inferior vena cava (IVC) filtration are narrow, but many filters are placed in patients with relative indications. There is growing concern for overuse of IVC filters, with a relatively low rate of retrieval. It is essential for interventional radiologists to understand the appropriate and correct use and retrieval of IVC filters. Familiarity with placement techniques, protocols and techniques for retrieval, current and emerging technologies, and the clinical model for management of venous thromboembolism, will ensure that interventional radiologists remain an integral member of the care team for these often complex patients.

Needs-Based Innovation in Interventional Radiology: The Biodesign Process.

There are many possible mechanisms for innovation and bringing new technology into the marketplace. The Stanford Biodesign innovation process is based in a deep understanding of clinical unmet needs as the basis for focused ideation and development. By identifying and vetting a compelling unmet need, the aspiring innovator can "derisk" a project and maximize chances for successful development in an increasingly challenging regulatory and economic environment. As a specialty founded by tinkerers, with a history of disruptive innovation that has yielded countless new ways of delivering care with minimal invasiveness, lower morbidity, and lower cost, interventional radiologists are uniquely well positioned to identify unmet needs and develop novel solutions free of dogmatic convention.

Inferior Vena Cava Filters: When to Place and When to Remove.

Pulmonary embolism (PE) is a common and feared result of deep vein thrombosis. While anticoagulation is the mainstay of management, interruption of flow of thrombus from leg veins to the pulmonary circulation is frequently desired either in lieu of or in addition to anticoagulation. Inferior vena cava filters have become frequently used to prevent PE despite a paucity of evidence for efficacy and increasing concerns about the long-term complications of indwelling filters.

Alternative Aortic Access: Translumbar, Transapical, Subclavian, Conduit, and Transvenous Access to the Aorta.

Large-caliber access to the arterial system is more frequently required in the age of thoracic endovascular aneurysm repair, endovascular aneurysm repair, and transaortic valve implantation. Frequently either anatomical or vessel size constraints preclude use of common access points such as the common femoral, radial, and brachial arteries. Alternative approaches include percutaneous access at alternate sites (subclavian, axillary, and carotid), open surgical access to the heart (left ventricular apex), open surgical access to large-caliber vessels (ascending aorta, subclavian, and axillary arteries, retroperitoneal access to the iliac artery or distal aorta), and novel percutaneous approaches (transvenous). Such approaches require additional skill sets, equipment, and, frequently, multidisciplinary teams to ensure safety and success. The techniques and approaches outlined in this article may allow expansion of endovascular treatments to greater patient populations and disease states than previously thought feasible.

Milestones in magnetic resonance imaging and transcranial sonography of movement disorders.

Twenty-five years ago, when this journal was initiated, imaging of movement disorders was in its infancy. Since that time, magnetic resonance imaging has become a standard technique that is routinely performed in patients with movement disorders in order to exclude secondary causes and in some instances to provide specific information that aids in making the diagnosis of a neurodegenerative condition. Transcranial sonography is a more recent advance and is now widely employed to aid in the diagnosis of Parkinson's disease and possibly in detecting individuals in the premotor phases of the disease. Investigations are currently under way to evaluate the value of this technique in other movement disorders.