Long-term follow-up of Vena Tech-LGM filter: predictors and frequency of caval occlusion.

PURPOSE: To report the frequency of caval occlusion after Vena Tech-LGM filter placement and identify related factors and their potential clinical significance.

MATERIALS AND METHODS: The filter was inserted into 243 patients, 142 of whom met inclusion criteria for this prospective study. Follow-up examinations performed every 2 years included clinical evaluation, plain frontal radiography of the abdomen, duplex scanning of the inferior vena cava (IVC), and/or phlebocavography.

RESULTS: A progressive decrease in IVC patency was observed, reaching 66.8% at 9 years of follow-up. Complete caval occlusion occurred in 28 patients and was significantly (P < 10(-6)) associated with retraction in 24 cases. Caval occlusion was not related to age, sex, pulmonary embolism (PE), deep venous thrombosis level, underlying conditions predisposing to a thromboembolic disease before filter insertion, the level of filter placement, use of anticoagulant therapy, and death during follow-up. PE with anticoagulation failure was a predictive factor (P = .016) of subsequent filter occlusion during follow-up as compared to all other clinical indications for filter placement. Filter patency at 9 years of follow-up was 35.2% in the PE group with anticoagulation failure and 80% for other patients (odds ratio, 2.5; 95% confidence interval 1.16-5.4).

CONCLUSION: PE with anticoagulation failure was the only factor predictive of subsequent caval occlusion observed in patients after Vena Tech-LGM filter placement. Caval occlusion was also related to Vena Tech-LGM filter retraction, which usually occurred at the time of occlusion.