clot filters, which are implanted in the veins of people at risk of
developing blood clots in their legs, eventually need to be removed or replaced to avoid complications. Complications
have been found to arise when the filters, even those intended to be
permanent, are left in longer than three to six months.
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.
‘Blood clot filters may be potentially dangerous and require specialized techniques to remove them. Using advanced tools radiologists have pioneered methods to remove these filters.’
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.
Rush team traps, covers, folds and removes filters
radiologists at Rush University Medical Center have pioneered methods
to remove filters that previously couldn't be removed for various
reasons. Some of the newest pioneered techniques are published in the
November issue of the Journal of Vascular and Interventional Radiology
by the interventional radiology team at Rush.
"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, 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
Thanks to these methods, the Rush team has achieved a 100% 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 anesthesia 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 five 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.
All patients with an IVC filter should consult specialist about removing it
Rush team lead by Bulent Arslan and Ulku Turba 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. Arslan is associate professor of radiology and
director, vascular and interventional radiology. Turba is associate
professor of diagnostic radiology.
While there are a variety of
risk factors and illness that can lead to blood clot formation, some
blood clots produce no symptoms until they become dislocated and travel
to other sites in the circulatory system. Some of the causes of blood
clot formation can include heart conditions, prolonged immobility,
smoking, surgery or inherited blood-clotting disorders.
retrievable filters were approved by the U.S. Food and Drug
Administration (FDA) in 2003 and 2004 and were recommended for deep vein
thrombosis (leg pain due to circulation problems caused by clots) in
2012. The length of time the filter is left inside the body depends on
the expected amount of time that protection is needed to prevent a blood
clot from traveling up to the heart and lungs.
filters are not always removed once the initial threat of a blood clots
traveling to the heart and lungs subsides, because there hasn't
previously been awareness of the potential risks of leaving them in,"
says Sreekumar Madassery, an interventional radiologist at Rush
University Medical Center and Rush Oak Park Hospital.
The FDA now
recommends that anyone who has an IVC filter talk to an interventional
radiologist about having the filter removed as soon as possible. Not
every filter should be removed, but everyone who has one should be