Use of emboli-blocking filters increases, but rigorous data are lacking

Emboli-blocking filters placed in the inferior vena cava to trap blood clots before they reach the lungs have been used for more than 30 years. But the recent expanded use of these filters has given rise to concerns about the lack of long-term data and patient follow-up after placement. The possible complications of a permanent device has led to the development of retrievable filters, designed to prevent fatal pulmonary embolism during high-risk events but allowing for subsequent removal.