Uterine fibroid (artery) embolization. Ken U. Ekechukwu, MD, MPH, FACP.

What is uterine fibroid embolization?
Uterine fibroids are benign tumors (noncancerous) that grow in the uterus. There may be one or countless fibroids and they grow in any part of the uterus, frequently disfiguring it and making it grow to enormous proportions. These tumors grow and multiply under the influence of the female hormone, estrogen, which explains why they are commoner in women of child-bearing age and begin to shrivel at menopause (except in menopausal women who take hormonal replacement therapy, who may remain symptomatic from fibroids). They occur in women of all races, but are commoner in African American women and nulliparous and low-parity women.

Many women are unaware that they have fibroids because not all fibroids cause symptoms. Symptomatic women may complain of one or several of the following:
1. Heavy, irregular, and prolonged menstrual blood loss that leads to anemia over time.
2. Anemia causes many symptoms and may behave like many other diseases (Easy fatigability, exercise intolerance, dizziness, shortness of breathe, palpitations, etc.).
3. Fibroids can press on nerves in the pelvis and cause radiating pain in the legs.
4. If the womb is large enough it may result in frequent urges to urinate or cause constipation.
5. Sex and menstruation may become painful.
6. When sufficiently large the womb may bulge the abdomen.

Troublesome fibroids (symptomatic fibroids) bring a woman to her doctor’s attention; the quiet ones do not. Most of the women who seek help do so because of heavy and irregular menstruation.

There are several treatment options for symptomatic fibroids: oral contraceptive pills, hormonal injections, myomectomy (the ‘shelling’ out of fibroids), hysterectomy, thermal ablation, and uterine artery embolization. Each has its merits and demerits and the reader is encouraged to consult their health care provider for what these are.

Uterine fibroid embolization is the stopping of blood flow into the uterus by injecting embolic agents into the uterine arteries. Embolic agents are floating particles of finite sizes composed of biocompatible materials. These particles plug blood vessels whose sizes match theirs and prevent blood and nutrients from reaching tissues beyond the obstruction causing tissue death. Since fibroids receive more blood flow than the rest of the womb, they get the bulk of these particles and the lack of nourishment causes them to die and involute (shrink). 8 to 9.5 women out of 10 women with symptomatic uterine fibroids who undergo UFE for heavy bleeding report dramatic cessation of their problem or sufficient reduction in the amount of their monthly blood loss that pleases them. This statistic may not hold true if the reason for heavy menstrual loss is a disease other than fibroids. Sometimes such disease co-exists with uterine fibroids and alters the statistic as well. A good example is when uterine adenomyosis co-exists with uterine fibroids and contributes to a woman’s menstrual disorder, a situation that I have found in my experience forecasts a reasonable chance failure of UFE to control the menstrual anomaly. Thus, it is wise to exclude other uterine diseases that cause abnormal menses before proceeding with UFE/UAE, so that the patient and her physician are well prepared for any persistence of symptoms after the treatment; this information has made many a woman decline UFE/UAE in my practice.

How is UFE/UAE done and what should I expect after it?
UFE is not major surgery, rather, like many interventional radiological procedures, it requires little invasion of the body. It is performed in an interventional radiology suite because it requires the use of fluoroscopy (x-rays) for guidance.  It is performed with attention to asepsis and under conscious sedation using a combination of an opiate and a benzodiazepine. The operator finds the arteries that supply your uterus by passing a catheter (a small tube, about the size of uncooked spaghetti) through the artery in one or both groins or the artery in your left arm, using the flow of the radiocontrast (iodine dye) which he injects through the catheter as a road-map. Once he confirms that the tip of the catheter is at the right place in the right vessel, he injects the embolic agent until blood flow into the womb ceases or is significantly reduced.

You will then receive treatment for symptoms caused by the dying fibroids – nausea, vomiting, diminished appetite, abdominal pain, low-grade fever, and a general sense of feeling unwell – collectively called ‘post embolization syndrome’. These symptoms vary in intensity from patient to patient and in most women respond to supportive care; they last from 3 days to 3 weeks. Most of my patients feel well enough the next day to go home; a few have gone home the same day.  They receive prescriptions for medicines to control pain, relieve nausea, prevent infection, and soften their stools and a majority are ready to return to work or resume normal activities in a little over 1 week.

Most patients report passing thin darkish vaginal flow for a few days after their UFE; some resume normal menses after a few months of amenorrhea; others report amenorrhea for many months that merges into menopause; some in a few weeks or several months after the treatment call to report spontaneously passing meaty materials in the toilet bowl, which are fragments of disintegrating fibroids; and yet a very few report lack of change in their initial complaint. Post-UFE experience in my practice varies and I have successfully dealt with it by reassuring and counseling each patient when the frantic call comes. Practically, all show on their follow-up pelvic MRIs variable degrees of reduction in the volume of the uterus and evidence of devascularization and death of the fibroids. Dead fibroids never recur but new ones may develop and grow if the woman is young enough.

How do I prepare for UFE/UAE?
In addition to making necessary arrangements for your absence from home and work, you should prepare yourself mentally and emotionally for UFE. In truth, however, there is not much to fret over for the procedure, particularly if you have researched the procedure well and have had reassuring discussions with your physician. By now you should have completed the investigations necessary for undergoing the procedure: endometrial biopsy (if necessary) to exclude uterine cancer as reason for the bleeding problem; magnetic resonance imaging of your pelvis with intravenous administration of a gadolinium chelate which documents the state of the uterus, the endometrium, the ovaries, your pelvic and gonadal veins and your bone marrow; and blood work to assess your renal function, the severity of your anemia, and your likelihood of bleeding excessively during the procedure. Since you are likely to receive conscious sedation, it is wise to refrain from eating and drinking 6 to 8 hours prior to your procedure.

Who needs UFE/UAE and what are its contraindications?
If you have asymptomatic fibroids (fibroids that do not cause you symptoms) you do not have to have UFE or other treatment for them.

Some women ask to have UFE because they wish to lose weight. Well, although the return to normal size of a womb massively enlarged and grotesquely distorted by many fibroids is likely to come with some weight loss, this is likely to be marginal and will happen slowly over time. Remember that the fibroids do not evaporate into thin air over night after UFE; they took time to grow and will take time to shrink. So I do not flash the image of rapid weight loss as an inviting wand of promise to women seeking UFE for that purpose.

Many young women have symptomatic uterine fibroids and wish to keep their wombs because they are not yet done with having children or have not had any yet. They wish to know the likelihood of becoming pregnant after UFE. The jury is still out on this issue and I do not promise my patients the reward of improved fecundity after UFE. I know, however, that many women have become pregnant after UFE, carried their fetuses to term, and birthed uneventfully. I have had a few in my practice.

Perhaps UFE is best for the woman who is approaching menopause but saddled with the problem of torrential or difficult menstrual blood loss. Since we know that menopause will usher in relief of her symptoms, UFE, instead of hysterectomy, for her problem seems wiser given its simplicity; here UFE serves a bridging role into menopause.

The uterine arteries may be embolized for many other uterine bleeding problems, for instance, post-partum hemorrhage and adenomyosis of the uterus. However, the success rate of UAE for stopping bleeding due to adenomyosis in my experience is much lower than it is for symptomatic uterine fibroids (vide supra). Adenomyosis may coexist with fibroids, which is one other reason I obtain MRI of the pelvis for all my patients. It is prudent for the patient and the physician to be aware of the likelihood of treatment failure before embarking on applying UAE for adenomyosis. My approach to this issue is to present the facts to the patient, help her understand that hysterectomy may be used as a fall-back alternative in the event of UAE failure, and let her decide what option to choose.

Abnormal uterine or vaginal bleeding in a menopausal woman should not be treated with UFE, but investigated and its reason determined. Such bleeding may be ominous.

What are the complications of UFE/UAE?
The risks or complications of UFE are few. Since it is done with conscious sedation, the risks associated with general anesthesia do not exist. Since there are no major incisions, the risks associated with wound infection are absent, although the uterus may become infected after embolization. This is preventable and treatable with antibiotics. There may be complications at the puncture site (bleeding, hematoma, infection, finger numbness or paresthesia), all of which are rare, preventable, and treatable.  Another rare and preventable complication is the unintentional flow of the embolization particles to other arteries resulting in tissue ischemia or infarction. Minor non-target embolization of a well-vascularized area may not cause major problems, whereas more serious occurrence may be problematic and is best avoided by attention to embolization technique.