Inferior vena cava filters simply have one purpose, that is to prevent thrombus (blood clot) travelling from the legs or pelvis into the right side of heart and lungs (pulmonary embolus = PE).
Associate Professor Lyon is a world expert on IVC filters and has been asked to speak locally and internationally on this subject. He is widely published on filters and is a consultant to both Cook Medical and Bard. Stuart’s opinion is also sought on complex retrievals and advice on filter removal techniques.
IVC filters were shown to be highly effective in the prevention of pulmonary embolism (blood clot travelling into lung arteries) in a randomised trial called PREPIC. There has been an increasing incidence of PE and use of modern filters (permanent/ retrievable IVC filter) throughout the world over the last 15 years. The modern filter or permanent/retrievable filter, is designed to take the effectiveness of IVC filters as shown in the PREPIC study and minimise the complications of long term filter use, by having these devices retrieved and removed when no longer needed.
Stuart can be contacted through Melbourne Endovascular for opinions on when to remove filters, anticoagulation for filters and PE/DVT, options for previously failed retrievables, complications of or problematic filters, periprocedural management of high risk DVT or PE patients, treatments of large DVT or PE. Stuart has designed a number of techniques to allow for high retrieval rates in his practice. Recently, Melbourne Endovascular added the “Jaws of life” rigid bronchial forceps, which now allows us to have filter retrieval rates of very close to 100%. Stuart is not infrequently asked to look at retrieving filters from both interstate patients and patients who have previously had failed or traumatic attempts at filter retrievals.
A 41 year old lady who had an IVC filter implanted 7 months earlier after bowel surgery, was complicated by large DVT and massive PE. The patient had a predisposition to blood clots (thrombophilia), and spent a complicated course in ICU post surgeries. There was no longer a need to keep the IVC filter after the patient was out of hospital and there was some occasional fever which raised concern of the filter being infected.
Two retrievals had been attempted interstate, but were unsuccessful. The patient was referred to Stuart Lyon and the filter was retrieved under general anaesthetic, using rigid bronchial forceps (see Image 2), to detach the heavily tethered filter from the IVC wall and retrieve safely (see Image 1).
“There is no doubt this filter saved this patient from a further large and very devastating pulmonary embolus, looking at the burden of clot that has landed in this filter. However, it is good to be able to remove this clot and filter so we do not see any of the longer term problems with such a chronically implanted device.”
The patient was delighted and luckily no infection could be found on the filter.
Image 1 - Retrieved filter with organised clot.
Image 2 - Using rigid bronchial forceps.