Most filters – whether for water or a furnace – eventually need to be removed or replaced to avoid complications.
Blood clot filters, which are implanted in the veins of people at risk of developing blood clots in their legs, require a similar precaution.
Complications have been found to arise when the filters, even those intended to be permanent, are left in longer than three to six months. These complications may include part of the filter breaking off and traveling to the heart and lungs, abdominal pain, filter tilt, and the filter tearing or creating a blockage in the veins of the abdomen (inferior vena cava) or in the legs. The chance of complications increases the longer the filter has been in place. Blood clot filters, also known as inferior vena cava (IVC) filters, potentially are dangerous and require specialized techniques to remove them.
Interventional radiologists at Rush University Medical Center have pioneered methods to remove filters that previously couldn’t be removed for various reasons.
‘We have both the standard retrieval methods as well as the most advanced tools to remove any type of filter, and we have the medical expertise to treat any complications from the filter being implanted,’ says Osman Ahmed, MD, primary author and interventional radiologist at Rush University Medical Center and Rush Oak Park Hospital.
The techniques involve a careful method of catching or ‘snaring’ the filter to hold it in place and then covering it to prevent parts of it breaking free. The team also uses tools such as alligator forceps and excimer laser in removing filters.
Thanks to these methods, the Rush team has achieved a 100 percent retrieval rate over the past five years, including difficult-to-remove filters from patients who have been referred to Rush from other hospitals.
The minimally invasive procedure is performed on an outpatient basis using twilight (conscious) sedation in the interventional radiology suite, which is similar to an operating room but also includes special imaging equipment. More advanced retrievals are performed using general anaesthesia due to the time it may take to remove the filter.
The filter removal is performed through a small incision in the neck or groin (the maximum size is around 5 mm) and the filter is removed using X-ray guidance to manipulate wires, catheters, and other devices necessary to remove the filter, which can be up to 29 mm in length.
The Rush team lead by Bulent Arslan, MD, and Ulku Turba, MD, developed these techniques to remove IVC filters, which are implanted in the inferior vena cava, a large vein just below the kidneys, in order to trap blood clots before they travel to the heart and lungs and cause permanent damage.
Rush University Medical Center www.newswise.com/articles/pioneers-in-ivc-filter-removal