Prevalence of local venous thrombosis after transfemoral placement of a Bird's Nest vena caval filter.

Bird's Nest vena caval filters were placed in 63 patients over a 6-month period by means of a transfemoral (n = 62) or transjugular (n = 1) approach. To determine the prevalence of access-site thrombosis, compression color Doppler flow imaging was performed 1-11 days after the procedure in 48 patients without suspected or documented preexisting thrombus. Clinical follow-up was from 5 to 289 days (mean, 100 days). Findings at ultrasound (US) examination were normal in 38 patients, and all of these patients remained clinically asymptomatic. Nonocclusive thrombus was seen in nine patients, eight of whom remained asymptomatic. A single patient had an occlusive thrombus at US. This patient had leg swelling. Nonocclusive thrombus did not predispose patients to the development of clinically evident occlusive thrombosis. The authors conclude that the transfemoral placement of the Bird's Nest vena caval filter is associated with a low prevalence (2%) of femoral vein occlusion documented at US follow-up. This contrasts with results from a similarly designed study demonstrating a 17% prevalence after percutaneous Greenfield filter placement.