Long-term follow-up of the bird's nest IVC filter

AIM: This study is a long-term clinical follow-up of the Bird's Nest Filter which addresses issues such as caval patency, filter integrity, morbidity and mortality. MATERIALS AND METHODS: 78 consecutive patients with Bird's Nest Filters inserted between 1989 and 1994 were recalled for clinical assessment and imaging follow-up. Pre- and post-filter medical histories were obtained from the patients and their medical records. They were examined for clinical signs of inferior vena cava occlusion. Imaging follow-up was by plain abdominal radiography, colour duplex ultrasound and computed tomography. RESULTS: 52 patients were alive and well at 4–6 years. Thirty-day mortality was 5.1 %. Three-year mortality was 19.2%. Recurrent pulmonary embolus occurred in 1.3%. IVC occlusion was demonstrated in 4.7%. No evidence of filter migration was seen. Wire prolapse occurred in 70% on abdominal X-ray and asymptomatic performation of the caval wall in 85.3% on CT. Morbidity and mortality were the same whether the patient was anticoagulated or not. CONCLUSION: The Bird's Nest Filter is safe and effective in both the short and long term.