Uterine Fibroid Embolization

James B. Spies and Ferenc Czeyda-Pommersheim

Uterine fibroid embolization (UFE) was first reported in the United States in 1997 as a minimally invasive alternative to hysterectomy and myomectomy for treatment of fibroids.¹ Since that time, its effectiveness has been confirmed by other investigators, including in two major randomized comparative trials,^2,3 and it has rapidly been incorporated into practice. In 2008, the American College of Obstetricians and Gynecologists, based on good and consistent scientific evidence (level A), concluded that “based on long- and short-term outcomes, uterine artery embolization is a safe and effective option for appropriately selected women who wish to retain their uteri.”⁴ With this acknowledgment, uterine artery embolization is now widely accepted as an alternative to hysterectomy.

Indications

Despite the very high incidence of uterine fibroids, many patients are asymptomatic. The most common symptom associated with uterine fibroids is heavy menstrual bleeding. Other symptoms include dysmenorrhea, pelvic pain and pressure, urinary frequency, and hydronephrosis. Fibroids have also been implicated in reduced fertility, infertility, and complicated pregnancies.

Most patients with symptomatic fibroids are candidates for UFE, and it is indicated for those who wish to avoid major surgery or definite loss of reproductive capacity. Although there are no well-established guidelines for UFE patient selection, in general, the size and extent of fibroids determine a patient’s suitability for embolization.

Fibroid location is also a consideration in patient selection, since there is some evidence that location may impact outcome ⁵ (Fig. e76-1). Submucosal fibroids shrink more rapidly than intramural fibroids, and intramural fibroids shrink more rapidly than those on the serosa. There are some fibroid locations that are likely less favorable, and these are discussed further under Contraindications.

FIGURE e76-1 Types of uterine leiomyomas. (Copyright David Klemm, 1998.)

Contraindications

UFE is contraindicated in patients who are pregnant or if uterine, cervical, or endometrial malignancy is suspected. Thus, patients with fibroids and imaging findings suggestive of malignant degeneration or patients with indeterminate adnexal masses merit further evaluation prior to proceeding with embolization.

Postmenopausal bleeding is rarely due to fibroids and always warrants endometrial biopsy to rule out malignancy. Similarly, we believe patients with marked irregularity of menstrual bleeding, which we define as vaginal bleeding more frequent than every 21 days or lasting longer than 10 days, should be considered for endometrial biopsy. Although continuous or frequent bleeding may occur with intracavitary or partially intracavitary fibroids, this type of bleeding pattern may also be caused by endometrial hyperplasia, polyps, endometrial malignancy, or other nonfibroid causes.

There are some specific subtypes of fibroids that may be best managed with surgery. Intracavitary fibroids, particularly when less than 3 cm, may be resectable using hysteroscopic methods. If a gynecologist skilled in hysteroscopic resection is unavailable or fails to remove the fibroid, embolization is certainly effective for this type of fibroid. Large serosal fibroids are often easily resectable by myomectomy, and the decision whether embolization or surgery is preferred depends on a number of factors. In most cases where the patient would like to become pregnant and when there has not been a previous myomectomy, surgery may be preferred. This is particularly true for very large fibroids that are mostly outside the uterine wall. The extreme example of a large narrow-based, completely pedunculated serosal fibroid is usually best treated surgically. This type of fibroid is likely to have relatively less shrinkage than other fibroids and is prone to adhesion formation. Similarly, for a woman with a massive uterus (>24 weeks size), the degree of shrinkage in the uterus may not be sufficient to provide long-term patient satisfaction, and these patients may have a better long-term outcome with surgery.⁶ Finally, there are some specific fibroid locations, notably broad ligament fibroids and cervical fibroids that anecdotally do not respond to UFE or respond poorly. These fibroids can be a therapeutic conundrum, since they are not easily treated surgically if the uterus is to be spared.

Equipment

One of the advantages of uterine embolization for interventional radiologists is that the procedure requires no equipment that is not usually on the shelves of any well-stocked interventional suite.

The first requirement is for an angiographic unit with a digital roadmapping or similar digital guidance system, essential if this procedure is going to be performed in a safe manner with a minimal fluoroscopic dose. Pulsed fluoroscopy is also very important to reduce patient radiation dose, and the pulse rate should be no higher than 15 pulses per second to minimize radiation exposure.

Standard 4F or 5F selective angiographic catheters are typically used for entry into the hypogastric arteries. Large-bore (0.025- to 0.028-inch lumen) microcatheters with appropriate microwires are required in patients with small or very tortuous uterine arteries, and many operators use them in all cases.

Embolic material is the central requirement of the procedure. Although Gelfoam pledgets or slurry have been used in rare cases, there is relatively little study of the effectiveness of the material outside Japan. The vast majority of fibroid embolizations in Western countries have been performed using particulate or spherical embolic materials.⁷ These are discussed later in the section on technical controversies.

Technique

Anatomy and Approach

The internal iliac artery provides the majority of the blood supply to the pelvis and inner thigh. The internal iliac artery bifurcates to an anterior and posterior division in 57% to 77% of the general population.8,9 Uterine fibroid tumors derive their main peripheral blood supply almost exclusively from the uterine artery.¹⁰ The uterine artery is the first or second branch of the anterior division of the internal iliac artery in 51% of the general population. The contralateral anterior oblique view is best used to image this variant. The uterine artery arises from a trifurcation of the internal iliac in approximately 40%, which is best imaged by the ipsilateral anterior oblique projection. In approximately 1% of the population, the uterine artery is absent; in these cases, it is often replaced by the ipsilateral ovarian artery.¹⁰