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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