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 ins
erted between 1989 and 1994 were recalled for clinical assessment and imagi
ng 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 r
adiography, 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 occu
rred in 1.3%. IVC occlusion was demonstrated in 4.7%. No evidence of filter
migration was seen, Wire prolapse occurred in 70% on abdominal g-ray and a
symptomatic performation of the caval wall in 85.3% on CT. Morbidity and mo
rtality 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. Nicholson, A. A. et al. (1999) Clinical Radiology 54, 759-76
4. (C) 1999 The Royal College of Radiologists.