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

To report the mid-term results of 63 patients who received a new commercially-available retrievable vena cava filter, ALN.

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.

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-up 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-up 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).

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.