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INFERIOR VENA CAVA FILTRATION
Blood clots in the veins of the legs (deep venous thrombosis also known
as DVT) is a common medical condition. It occurs most frequently in patients
bedridden from surgery, injury, or illness, but may occur in otherwise
healthy active individuals. Typically, this condition is treated with blood
thinners to prevent new clot formation. Clots in the legs can break loose
and travel to the lungs where they cause serious illness (pulmonary embolus
also known as PE). Not all patients are candidates for treatment with blood
thinner. Inferior vena cava filtration is an alternate treatment.
An inferior vena cava filter is a metallic filter-like device
placed in the large vein in the back which drains the blood from the legs
back to the heart and lungs. The filter is used for the prevention of
recurrent pulmonary embolism in the following situations:
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Diagnosis of deep venous thrombosis or pulmonary embolism when blood
thinners can not be used. For instance, an active bleeding ulcer would be a
reason not to treat with blood thinner.
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Failure of blood thinner therapy. Some patients will develop new or
progressive blood clots in the legs or blood clots that break loose and go
to the lung despite adequate blood thinner treatment.
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Large floating clot. When imaging tests demonstrate a very large or loosely
attached clot in a large vein of the leg or pelvis, a filter may be
required. Large unstable clots are the type which are likely to cause
serious illness if they break loose and go to the lungs, and blood thinners
may not be adequate to prevent this.
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Patients with previous pulmonary embolus or deep venous thrombosis who have
severe heart or lung disease may not be strong enough to survive another
pulmonary embolus. Inferior vena cava filtration may be warranted in these
cases.
 An
inferior vena cava filter is a metallic device that looks like a
tiny cage.
Procedure
The procedure may be performed as an outpatient. The neck or groin is
washed, then a local anesthetic is administered. A small nick is made in the skin, and a
small plastic tube is advanced into the inferior vena cava (the large vein
that returns blood from the legs to the lungs). X-ray dye is injected and
x-rays are obtained for the purpose of evaluating the inferior vena cava.
These pictures are studied to determine the ideal location for filter
placement. Then, through the same small nick, the filter is advanced. It is
"spring loaded", and is released into the blood vessel. In that position, it
can trap clots that break loose from the legs and prevent them from
traveling to the lungs. The small tube is removed and a band-aid is applied.
If the patient is not bedridden and does not require prolonged bed rest for
other medical conditions, activity can be resumed in several hours. The
filters are permanent and good for life. They need no periodic maintenance
and they do not set off metal detectors.
NON-SURGICAL BIOPSY OR ASPIRATION
In some medical conditions, masses or fluid collections may develop
within the body and biopsy or aspiration may be necessary for diagnosis. As
well, some conditions are diagnosed by taking a small biopsy of an organ
such as the kidney or liver. Masses of the lung or thyroid are often
diagnosed with non-surgical biopsy.
Conventional open or surgical biopsies involving incision are
not always necessary. An interventional radiologist is trained and skilled
at using image guidance (ultrasound, CT or fluoroscopy) to precisely place a
needle in the correct location and obtain a biopsy. This eliminates the need
for surgery.
The first step is for the radiologist to review pertinent imaging such as CT
or US which demonstrates the area of interest. If the area of interest is
accessible with a small needle, blood work will be obtained to check for any
bleeding disorders and the patient will be scheduled for the biopsy usually
as an outpatient.
On the day of the procedure, patients are asked not to have
anything to eat or drink except necessary medications with small sips of
water. Often an IV will be placed to allow administration of relaxing
medications. The patient will be placed on a table and images will be
obtained of the area of interest for the purposes of accurately localizing
the area for biopsy. Relaxing medicines are administered if needed and the
area is washed with sterile soap. Numbing medicine is applied. Then using
image guidance, a small needle is advanced into the area of interest and
several biopsies are obtained. The biopsy is sent to the laboratory for
interpretation by a pathologist. The needle is removed and a band-aid is
applied. The recovery period and time to return to regular activities is
determined by the region of the body which is biopsied.
Results in most cases are available in about two working days. This
information is sent to the physician who requested the biopsy.
What are the risks? All procedures involve some risk. Due to
precise localization with image guidance and use of small needles, the risks
generally are small, particularly compared with surgical biopsies. Possible
complications include discomfort, bleeding, infection and puncture of an
adjacent organ. Fortunately, these complications are uncommon. Risks are
minimized by checking blood work and patient history for risk of bleeding,
use of sterile techniques and small needles, use of accurate image guidance
and performance by a skilled radiologist.
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