Thrombus Embolization Into IVC Filters During Catheter-Directed Thrombolysis for Proximal Deep Venous Thrombosis

Purpose: To assess the frequency of embolization into retrievable inferior vena cava (IVC) filters during catheter-directed thrombolysis (CDT) and stent placement for acute iliocaval deep venous thrombosis (DVT). Methods: Serial phlebograms from 40 patients (28 women; median age 32 years) consecutively treated with CDT for DVT during a 12-year period were retrospectively evaluated for visible emboli in the IVC filter. Clinical and procedural data extracted from a prospectively maintained database were evaluated to identify predictors for embolization into the filter. Results: Visible emboli were found in 18 (45%) patients. Visible embolization to the IVC filter was less frequent in patients with a hypercoagulable disorder (n=29, 31%) than in patients without a hypercoagulable disorder (n=11, 69%; OR 0.1, 95% Cl 0.02 to 0.56, p=0.006). No patient developed clinical symptomatic pulmonary embolism or a complication related to the placement or retrieval of the IVC filter. Conclusion: Thrombus embolization during CDT is a common phenomenon in patients with proximal DVT. Placement of a retrievable IVC filter during thrombolytic therapy can prevent silent and symptomatic pulmonary embolism.