Uterine fibroid embolization (UFE), or uterine artery embolization, is a minimally invasive treatment for uterine fibroids that can relieve symptoms without surgery. There is no large surgical incision or scar, less pain than surgery and recovery in seven to 10 days. This procedure was first performed in the United States in 1997 and MedStar Georgetown is recognized world-wide as a leading center in this procedure, with one of the most experienced teams in the world. MedStar Georgetown researchers have published more studies on this procedure than any other group in the country.

Very few side effects or complications are experienced with UFE. More importantly, research has shown that the risks and complications are significantly lower than surgery.

UFE involves injecting microscopic particles into particular targeted arteries to selectively block blood flow to the fibroids, causing the fibroids themselves to gradually and consistently shrink over time. This procedure is 90 percent effective in treating bleeding caused by fibroids, and there are virtually no significant risks.

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

Uterine Artery Embolization catheterThe procedure is usually done in the hospital with an overnight stay 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 at right). 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.

Uterine Artery Embolization closeupBoth 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.
There is variability in the technique used at different centers that are performing UAE. At MedStar Georgetown, a second arterial catheter is placed from the opposite femoral artery to the other uterine artery and the embolizaton of the fibroids is done from both sides simultaneously. At other centers, a single catheter technique is used with one side treated then the other. In any case, all physicians who are performing UAE treat both uterine arteries.
There are other variations in technique, including the use of different types and sizes of particles to block the arteries. Many patients have questions about the particles and their fate. 

 

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 embolization. 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. We have completed a study on ovarian function after uterine embolization. In women under the age of 45, there was no permanent change in FSH, a hormone often used to estimate ovarian reserve.

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%. We have recently reviewed our experience in the first 230 patients treated at MedStar Georgetown and we have summarized our complications. 

Expected Result

As of this time, 20.000 to 25,000 patients have had this procedure world-wide. Our initial results, along with those 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 quality of life of patients also improves significantly. Again in research completed here at MedStar Georgetown, with either a quality of life questionnaire specific for fibroids or a more general questionnaire, statistically significant improvement is evident in all areas.
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.

Pregnancy after UAE

While UAE has not been used as a fertility procedure, there have been many pregnancies after uterine artery embolization.

The long-term effect that UAE may have on a woman's ability to have a child is not known. It may reduce chances of becoming pregnant for some women, but in others it may be just as likely that the chances will increase.

There are a number of ways that pregnancies may be affected by UAE. During the procedure, some of the flow in the uterine arteries is decreased at least temporarily. It is uncertain what effect this will have on the ability to become pregnant or to carry a pregnancy to term. It appears that in most patients, the arteries reopen to the normal parts of the uterus and it is rare for there to be a permanent injury to the uterus. As the fibroids die and begin to shrink, in some cases this may weaken the wall of the uterus. This would appear to be most likely with large fibroids that span the entire wall of the uterus. However, fibroids compress the normal uterine tissue adjacent to them and as they shrink, we have seen the normal tissue restored to a more normal configuration. For any individual, it is difficult to predict whether the uterus will be weakened to the point where there might be a problem during delivery of a baby. For our patients that have become pregnant, we recommend that a sonogram be performed to assess the site of implantation and the overall integrity of the uterine wall.

Another potential effect of this procedure is the loss of menstrual cycles, with the onset of menopause. 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 cause is most likely 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 (1-4). 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 (5). It is very rare for a woman under the age of 45 to lose menstrual periods.

To further evaluate ovarian function after UAE, at MedStar Georgetown, we have completed a study on ovarian function after uterine embolization (6). Among the 35 women in the study under the age of 45, there was no permanent change in FSH, a hormone often used to estimate the likelihood of pregnancy. None of the women in that study had cessation of menstrual periods.

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