Mid-term experience with the ALN retrievable inferior vena cava filter

Objective. To report the mid-term results of 63 patients who received a new commercially-available retrievable vena cava filter, ALN. Methods. Between January 2001 and October 2005, 63 patients (mean age 65 15 years) underwent placement of ALN filters. Filter removal was performed when anti-thrombotic prophylaxis was considered unnecessary or when the patient could safely resume full anticoagulant therapy. Results. Thirty-five patients (55%) had ilio-femoral venous thrombosis and 28 patients (45%) had ilio-caval thrombosis. Overall, 49% had pulmonary embolism. Technical success for filter insertion was 100%, without any complications. None of the procedures aborted or was converted due to technical difficulties. After a median follow-tip of 21-months (range 1-48, median 18), there were no cases of pulmonary embolism or vena cava thrombosis. Two patients died of a cause unrelated to deep venous thrombosis during the follow-tip period, without clinical evidence of pulmonary embolism or filter-associated complications. No device migration was observed. There were 20 (31.7%) retrieval attempts: in 16 cases filters were retrieved successfully, but 4 cases were aborted. The mean implantation period of the retrieved filter was 179 days (range 53-370). Conclusion. Our results confirm the clinical efficacy of the ALN filter for preventing potentially fatal pulmonary embolism whilst implanted and in absence of post-insertion complications, even when left in place indefinitely.