Uterine
Fibroids & Uterine Artery Embolization for Fibroids
Uterine Artery Embolization for Fibroids (UAE/UFE)
Introduction
Uterine artery embolization represents a fundamentally new
approach to the treatment of fibroids. Embolization is a minimally
invasive means of blocking the arteries that supply blood to
the fibroids. It is a procedure that uses angiographic techniques
(similar to those used in heart catheterization) to place a catheter
into the uterine arteries. Small particles are injected into
the arteries, which results in their blockage. This technique
is essentially the same as that used to control bleeding that
occurs after childbirth or pelvic fracture, or bleeding caused
by malignant tumors. The procedure was first used in fibroid
patients in France as a means of decreasing the blood loss that
occurs during myomectomy. It was discovered that after the embolization,
while awaiting surgery, many patient's symptoms went away and
surgery was no longer needed. The blockage of the blood supply
caused shrinkage of the fibroids resulting in resolution of their
symptoms. This has led to the use of this technique as a stand-alone
treatment for symptomatic fibroids.
The Procedure
The procedure is usually done in the hospital with an overnight
stay or same day discharge post-procedure. The patient is sedated
and very sleepy during the procedure. The uterine arteries are
most easily accessed from the femoral artery, which is at the
crease at the top of the leg (Figure Below). Initially, a needle
is used to enter the artery to provide access for the catheter.
Local anesthesia is used, so the needle puncture is not painful.
The catheter is advanced over the branch of the aorta and into
the uterine artery on the side opposite the puncture.
Before the embolization is started, an arteriogram (an injection
of contrast material while X-rays are performed) is performed
to provide a road map of the blood supply to the uterus and fibroids.
After the arteriogram, particles of polyvinyl alcohol (PVA) are
injected slowly with X-ray guidance (see figure at left). These
particles are about the size of grains of sand. Because fibroids
are very vascular, the particles flow to the fibroids first.
The particles wedge in the vessels and cannot travel to any other
parts of the body. Over several minutes the arteries are slowly
blocked. The embolization is continued until there is complete
blockage of flow to the fibroids.
Both uterine arteries are embolized to ensure the entire blood
supply to the fibroids is blocked. After the embolization, another
arteriogram is performed to confirm the completion of the procedure.
Arterial flow will still be present to some extent to the normal
portions of the uterus, but flow to the fibroids is blocked.
The procedure takes approximately 1 to 1 1/2 hours.
Complications
Serious complications are rare after UAE, occurring in less
than 4% of patients. These include injuries to the arteries through
which the catheters are passed, infection or injury to the uterus,
blood clot formation, and injury to the ovary.
The most severe complications to date have been 4 deaths reported
after UAE, 3 in Europe and 1 in the United States. In England,
a patient developed a very serious infection in the uterus 10
days after the procedure. Despite a hysterectomy, the patient
developed septicemia (blood stream infection) and died 2 weeks
later. Another patient recently died in the Netherlands from
a similarly severe infection. There have been 2 deaths from pulmonary
embolus, which is the passage of a blood clot from the veins
in the legs or the pelvis to the lungs. Pulmonary embolus may
occur after any of a number of different surgical procedures,
including most gynecologic surgeries. It does not appear that
a patient treated with UAE is at any greater (or lesser) risk
for pulmonary embolus than surgery patients. While pulmonary
embolus usually does not result in permanent injury, it can cause
death in rare instances. These very serious complications are
the only deaths that have occurred in the 20,000 to 25,000 patients
treated worldwide thus far.
About 1% of the time, a patient might have an injury to the
uterus or infection in the uterus that might necessitate a hysterectomy.
Injuries to other pelvic organs is possible but has not yet been
reported. There have been a few patients that have had a nerve
injury, either in the pelvis or at the puncture site, although
happens in less than 1 in 200 patients. An injury to the puncture
site, such as clot formation or bleeding, is also similarly rare.
The most likely problem to develop in the first several months
after the procedure is the passage of fibroid tissue. This is
only likely to happen with submucosal or intramural fibroids
that touch the lining of the uterus. In our experience, this
occurs in about 2 or 3 % of cases. While the fibroids may pass
on their own, a D and C may be needed to remove the tissue. While
the passage of tissue may be beneficial in the long run, it may
be associated with infection or bleeding and this may be severe
enough to require hospitaliation. For this reason, it is important
to monitor this process carefully to avoid more serious problems.
X-rays are used to guide the procedure and this raises a concern
about potential long-term effects. There have now been several
studies of X-ray exposure during uterine embolization, and in
most of these, exposure was found to be below the level that
would be anticipated to have any health effect to the patient
herself or to future children. It is always possible that very
prolonged exposure could cause an injury, and there has been
one patient reported that developed a skin burn after uterine
artery embolization for fibroids. Most interventionalists limit
the duration of X ray exposure in any procedure and will stop
the procedure if it cannot be completed within a safe interval.
Another unresolved question is the effect, if any, of this
procedure on the menstrual cycle. The overwhelming majority of
women who have had embolization of fibroids have had decreased
bleeding with normal menstrual cycles. There have been a few
women (most of whom are near the age when menopause would be
expected) who have lost their menstrual periods after uterine
embolization. The most likely cause is decrease in blood supply
to the ovaries as a result of the embolization. Most researchers
have noted a 2 to 6% chance of losing menstrual periods and the
onset of menopause as a result of UAE. There has been one study
that noted a higher rate of menopause after the procedure (15%
of patients treated) but the reason for this higher rate is not
clear.
About 1% of the time, a patient might have an injury to or
infection in the uterus that might necessitate a hysterectomy.
Injuries to other pelvic organs is possible but has not yet been
reported and the chance of other significant complications is
less than 4%.
Expected result
As of this time, 20,000 to 25,000 patients have had this procedure
world-wide. The results that have been published or presented
at scientific meetings, suggest that symptoms will be improve
in 85-90% of patients with the large majority of patients markedly
improved. The improvement rate is similar for heavy menstrual
bleeding and for pressure and pain symptoms. Most patients have
rated this procedure as very tolerable and in almost all cases
hospitalization is necessary for only one night. In some centers,
the patients are treated and discharged the same day.
The expected average reduction in the volume of the fibroids
is 40-50% in three months, with reduction in the overall uterine
volume of about 30-40%. Over time, the fibroids continue to shrink.
With several years follow-up now available, it does not appear
that fibroids successfully treated regrow. It is not known whether
patients may develop new fibroids.
If you would like to consider this procedure or would like
more information about uterine artery embolization, please call
The Toronto Endovascular Centre at 416-925-2676.
While UAE has not been used as a fertility procedure, there
have been many pregnancies after uterine artery embolization.
Uterine Artery Embolization for Fibroids Case Study
Sanjoy Kundu BSc., M.D., F.R.C.P.(C), D.A B.R., FASA, Division
of Interventional Radiology
Scarborough Hospital – General Division, Scarborough, Ontario,
Canada
Case History:
47 year old female presented with a one year history of very
heavy periods lasting for four days during each menstrual
cycle. Her past medical and surgical history was otherwise
unremarkable. A MRI demonstrated a dominant intramural
fibroid in the uterine fundus (Figure 1). After assessing the
different therapeutic options, the patient chose to go ahead
with a
Interventional Procedure (Case performed at Scarborough General
Hospital – General Campus):
Uterine Artery Embolization Procedure for her fibroids. The
patient’s right common femoral artery was accessed. Using
a C2 catheter, the patient’s left uterine artery was cannulated
(Figure 2). One and a half vials of Contour SE PVA measuring
500-700um was injected, until there was complete stasis in
the main left uterine artery (Figure 3). Cannulation of the
right uterine artery was also performed followed by injection
of one and half vials of Contour SE PVA.
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Figure 1 |
Figure 2 |
Outcome:
A nine month follow up MRI demonstrated greater than 50 percent
reduction in size of the index fibroid. The patient’s menstrual
cycles also normalized with no episodes of heavy bleeding
during her periods (Figure 4).
Comments:
Uterine artery embolization for fibroids is a attractive,
less invasive treatment for women with symptomatic fibroids.
Uterine artery embolization is a viable and effective alternative
to surgical myomectomy or hysterectomy, without the postoperative
risks of bleeding, ureteric injury or pulmonary thromboembolism.
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Figure 3 |
Figure 4 |
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