Embolization Therapy: Principles and Clinical Applications, 1 Ed.

Uterine Fibroids

James B. Spies

Uterine fibroid embolization (UFE) is now well established as an effective treatment for uterine fibroids, with substantial evidence of its efficacy. Since the first published small case series reported by Ravina et al.1 in 1995, there have been hundreds of publications on the procedure, including several randomized trials. The accumulated evidence led the American College of Obstetricians and Gynecologists2in 2008 to recognize UFE as a safe and effective alternative to hysterectomy in women who have completed childbearing.

This chapter reviews the indications for UFE, the technical details of the procedure, periprocedural care, and anticipated outcomes, with the intent of summarizing this treatment option and its place in current fibroid management.

BACKGROUND

Leiomyomas are the most common tumor of the female reproductive tract, affecting a large proportion of women of reproductive age, with a cumulative incidence of 80% in African American women and nearly 70% in Caucasians by age 50 years in the United States.3 The prevalence is even higher if hysterectomy specimens are examined using serial thin uterine sections, with leiomyomas found in 77% of uteri in one study.4

Fibroids are a condition of women of reproductive age, typically arising in a patient’s 30s and regressing after menopause. The natural history of fibroids is typically progressive growth until menopause, with the greatest growth most likely in medium to large fibroids that are intramural.5 The growth rate is variable between patients and for individual fibroids within a single uterus.

Of those women with fibroids, a substantial proportion will develop symptoms during the course of their reproductive lives.6 The most common symptom is menorrhagia, which is often accompanied by cramping, pelvic pain, pressure, and increased urinary frequency. Less commonly, patients may have dyspareunia, urinary incontinence, urinary retention, or hydronephrosis. For many women, symptoms are of sufficient severity to warrant treatment.

TECHNICAL DETAILS

Patient Selection

To properly select patients for UFE, it is important that they be properly assessed with a gynecologic history and physical examination, including a pelvic examination by a medical provider experienced in gynecologic care. Often, this will be the patient’s gynecologist before referral for UFE evaluation. The diagnosis must be confirmed with imaging. The choice of imaging modality depends on available resources. Ultrasound certainly can confirm the diagnosis of fibroids and exclude other gynecologic pathology in most cases. However, the findings should be confirmed by personal review of the images rather than relying on the report alone. The quality of ultrasound examinations is very variable, and very poor quality or limited examinations should be repeated to ensure that other significant gynecologic pathology is not present.

Ideally, magnetic resonance imaging (MRI) would be the modality of choice for imaging fibroids and the uterus. It provides better spatial resolution and anatomic detail of the architecture of the uterus than ultrasound, and it also provides excellent assessment of adnexal structures. Some uterine conditions, such as adenomyosis, are much more reliably identified with MRI, and in one study, the management of patients was altered based on MRI findings in 22% of cases.7 Based on the MRI findings, UFE was not performed in 19% of women in whom the procedure was initially planned.

There are no clearly established criteria for who should or should not be treated with embolization. The evidence to date has not been definitive in establishing selection criteria. Some exclusion criteria have been suggested based primarily on a concern that some specific subtypes of fibroids or patients with certain clinical conditions might not do as well.8 The uterine-specific factors include uteri greater than 20 to 24 weeks size (potentially poorer outcomes), submucosal fibroids greater than 10 cm (due to potential increased risk of fibroid expulsion and infection), and pedunculated fibroids (either submucosal or serosal) that have an attachment to the uterine wall less than 50% the diameter of the fibroid (due to potential for detachment). Unfortunately, there is little evidence to support any of these suppositions, at least to the extent that the evidence makes these “contraindications.” For example, although there is some evidence that very large uteri may not have as much shrinkage as smaller uteri and patient satisfaction may trend lower,9 there are other studies suggesting this is not the case.10 Similarly, there is little evidence that narrow-based pedunculated fibroids are unsafe to treat.11,12

Other nonuterine factors that have been considered contraindications include large hydrosalpinx (due to perceived increased risk of infection), prior pelvic surgery, or procedure that might alter pelvic arterial anatomy, such as salpingo-oophorectomy or surgery for ectopic pregnancy or pelvic radiation. There is essentially no evidence to support these views.

Thus, there are few absolute contraindications and few proven relative contraindications. Clearly, current pregnancy or known or suspected uterine or adnexal malignancy are contraindications. Most anatomic limitations related to fibroids themselves are really in the context of considering the other treatment options for the patient. Large intracavitary fibroids may be more prone to expulsion, and in some cases, other treatments such as myomectomy or hysterectomy may be preferred. Similarly, a small pedunculated serosal fibroid in a multifibroid uterus may be best treated by UFE, whereas a large pedunculated single serosal fibroid might be better approached surgically with myomectomy.

Further, the question of future fertility must always be considered. Although the fertility outcomes are reviewed later in this chapter, the question of whether the patient is interested in future childbearing must be answered. The limited data available from randomized trials currently suggest that myomectomy should be the first consideration in a patient who would like to become pregnant in the subsequent 2 years.

When evaluating patients for UFE, the anatomy of the uterus, the presence or absence of adnexal abnormalities, the patient’s age, her interest in pregnancy, and her willingness to consider hysterectomy or other surgical alternatives all should be considered before making a recommendation for the patient. UFE is suitable for most patients with symptomatic fibroids, but so are other fibroid treatments. The patient should understand the range of the options for her in order for her to make an informed choice.

Technique

UFE is an angiographic procedure usually performed via femoral arterial access. Most practitioners use unilateral femoral access, usually on the right side. There is an alternate method, that of bilateral femoral access, which has been used by some groups. Because each UFE usually requires embolization of both uterine arteries, bilateral approach allows for simultaneous embolization. This results in shorter fluoroscopy times and shorter procedure times.13

Regardless of whether unilateral or bilateral access is used, UFE requires selective catheterization of the uterine arteries before embolization. There is some controversy regarding placement of the catheter tip within the vessel. Early in the development of UFE, a case report was published on a patient who experienced sexual dysfunction after UFE, and the authors speculated it could be from occlusion of the cervical vaginal branch of the uterine artery.14This lead to the belief that embolization should only be done with the catheter tip distal to that branch. This can be difficult as it often arises from the mid transverse portion of the uterine artery and is distal to multiple looping segments of the vessel. Even with the use of a microcatheter, placement of the catheter tip at that level can be very difficult. This degree of manipulation of the catheter can also cause significant spasm in the vessel. Because successful embolization of the fibroids depends on the free flow of the embolic material to the fibroid vessels, it is important to avoid spasm that might impede that flow. Thus, our approach is to place the catheter tip distal to that branch if feasible without causing spasm, but if not, then more proximal position would be acceptable.

Spasm both limits the flow to the fibroids but can also lead to a false end point, with the appearance that there has been adequate reduction in flow when in fact a part of the apparent reduction in flow is due to flow restriction from spasm. One means of trying to avoid or relieve spasm is the use of a microcatheter. Some interventionalists use them routinely for just that reason, whereas others use them selectively. Use of a microcatheter should be the first consideration in relieving spasm. Antispasm medications, such as nitroglycerin, may also be used to help relieve spasm.

Once the catheter(s) is (are) in appropriate position, most interventionalists will perform a preembolization arteriogram to verify anatomy, assess for communications with the ovarian arteries, and ensure there are no abnormal arteriovenous communications before embolization. There is at least one reported case of misembolization of embolic material due to a uterine arteriovenous fistula, with embolic material passing through a patent foramen ovale into the heart, brain, and other organs.15

Embolic material is injected in small aliquots, with the flow within the uterine arteries carrying the embolic to the fibroid vessels. The vessels feeding fibroids are very large compared to normal myometrial branches (Fig. 54.1). As a result, the flow to them is greatest initially. There is therefore preferential flow to the fibroids. Fibroids are supplied by a limited number of end vessels, and if these are occluded, collaterals cannot reperfuse the fibroid. Because fibroids are very sensitive to ischemia, the occlusion of the feeding vessels typically results in the complete or near complete infarction of the fibroid without injury to adjacent normal myometrium (Fig. 54.2). The extent of fibroid occlusion can vary depending on the embolic material chosen and the end point of embolization. These two topics are discussed further in the following sections.

Although most patients will have uterine and fibroid supply from both uterine arteries, there are some variations. First, occasionally there is only one or perhaps two fibroids that are supplied by one vessel only, with the opposite uterine artery normal. These may be treated by unilateral embolization if certain conditions can be met. First, MRI should be used to clearly define the number and location of the fibroids and to confirm that they are only on one side of the uterus. Unilateral embolization of major fibroids and nontreatment of smaller fibroids on the opposite side will only hasten the recurrence of fibroids and should be avoided. With unilateral fibroids, angiography at the time of embolization must confirm supply to the fibroids from the one uterine artery only. The uterine artery that is to be considered for nonembolization must be normal, perfusing normal myometrium only. If these criteria are met, there is evidence that fibroid infarction rates will match those of bilateral embolization, and it is likely the patient will have diminished pain after embolization when compared to bilateral UFE.16,17

There are also variations of the uterine arteries or additional supply to the uterus or fibroids from other vessels, most commonly the ovarian arteries. Several studies have evaluated the frequency of ovarian artery supply to the uterus and it occurs in approximately 5% of cases.1820 Most interventionalists will perform an aortogram after embolization if ovarian supply from the uterus is suspected. Pelage et al.21recommended performing an aortogram in those cases in which there is a large uterus, a large fundal fibroid, prior myomectomy, or tubal surgery; a study should also be done in cases in which one uterine artery is diminutive or absent.

Currently, most experts recommend that if ovarian artery embolization is to be performed as an adjunct to UFE, a microcatheter should be used for selective catheterization of the vessel and that the tip of the microcatheter be advanced about a third of the distance from the origin to the level of the ovary. Embolization is typically performed with particulate embolics, and usually, only a small amount of embolic is needed, with an end point of near stasis regardless of embolic. In most cases of ovarian embolization, only one ovarian artery requires embolization. Although data are not extensive, it does not appear that embolization of the ovarian arteries increases the risk of ovarian failure after embolization.2224 Rarely, other sources of supply, such as the round ligament artery25 or the inferior mesenteric artery,26 can provide the uterus or fibroids and should be considered when neither the uterine or the ovarian arteries appear to provide all the vascular supply to the fibroids.

Embolic Material

There are several embolic materials currently available for embolization and also a considerable amount of literature regarding the relative effectiveness of these different products.

There are three embolic materials currently cleared by the U.S. Food and Drug Administration (FDA) specifically for UFE. These are trisacryl gelatin microspheres (TAGM, Embosphere Microspheres; Merit Medical Systems, Inc., South Jordan, Utah), polyvinyl alcohol (PVA) particles (Contour; Boston Scientific Corporation, Natick, Massachusetts), and spherical polyvinyl alcohol (sPVA, Contour SE; Boston Scientific Corporation, Natick, Massachusetts). There are additional materials that are cleared for use for hypervascularized tumors and that are regularly used for fibroid embolization. These are acrylamido PVA microspheres (Bead Block; Biocompatibles, Inc., Oxford, Connecticut), Polyzene-F–coated PVA hydrogel spheres (Embozene Microspheres; CeloNova BioSciences, Inc., San Antonio, Texas), and PVA particles (Cook Medical, Inc., Bloomington, Indiana). In addition, gelatin sponge is used in some settings, although it does not have FDA clearance for use as an embolic agent.

There have been several studies comparing the outcomes of embolization from different embolics. Based on the outcomes from some long-term studies, it has become clear that the best measure of an embolic’s efficacy for UFE is the extent to which the fibroids are infarcted.27 This has been measured by estimating the fibroid infarction rate, usually the estimated percentage of the visible fibroid tissue no longer perfused on a contrast-enhanced MRI.28

The first randomized comparative study of embolics for UFE was by Spies et al.,29 in which the outcomes of UFE using TAGM and PVA particles were compared. Surprisingly, there were few differences between the materials. Before that study, it was widely believed that the use of TAGM caused less postprocedural pain than PVA, but no difference was found. The fibroid infarction rates were nearly identical, with 77% of TAGM and 76% of PVA patients with complete fibroid infarction. This study set the benchmark by which other embolics would be subsequently be compared.

The same group initiated a second study comparing sPVA to Embospheres for UFE and surprisingly did find a significant difference between the two materials.30 There was a large difference in fibroid infarction rate, with sPVA having a mean residual perfused fibroid volume of 44% versus 9.6% for TAGM. The TAGM group also noted a greater improvement in quality of life scores at 3 months after treatment. Siskin et al.31 published a similar comparative study and had similar findings: treatment failure in 29.6% of the sPVA group and 3.8% for TAGM, with less fibroid infarction in the sPVA group. Additional studies have confirmed that for UFE, spherical PVA is not as effective as conventional PVA and TAGM for this procedure.

A single randomized trial has compared acrylamido PVA microspheres to TAGM. No difference in fibroid infarction rates was noted, although there was a better quality of life outcome for TAGM.32Unfortunately, there were only 44 patients in this study, a small number to compare the embolic efficacy. There have been other nonrandomized trials that have found poorer outcomes with acrylamido PVA, and at this time, the question remains unsettled.

There are case series supporting the efficacy of Polyzene-F–coated PVA hydrogel spheres (Embozene),33,34 with preliminary evidence suggesting excellent clinical outcomes and high rates of fibroid infarction. There are no comparative studies published to date with the product, although a randomized trial is ongoing currently.

There is relatively little published experience on the use of gelatin sponge for UFE in Western countries, but it has been the standard used in Japan for many years. Katsumori3537 has reported extensively on both the short- and long-term outcomes using this material, finding very similar short-, mid-, and long-term outcomes. Whereas in the West gelatin sponge is commonly used as a slurry or as large pledgets, in Japan, it is cut into very small particles of between 500 and 1,000 µm in size. It is not known whether this preparation is critical in obtaining good results.

End Points of Embolization

There has been much discussion over the years regarding the extent to which the uterine arteries need to be occluded to result in fibroid ischemia sufficient to infarct the fibroids. These discussions have been hampered by the lack of tools to objectively measure the end point. Most articles reporting results have used a descriptive end point that can be subject to variation in interpretation.

Initially, UFE was performed with PVA, with either a gelatin sponge plug or a coil used at the end of the embolization to completely occlude the uterine artery, leaving just a stump of a vessel.38,39 Although the initial results suggested this was successful in causing fibroid shrinkage and presumably fibroid infarction, it also resulted in very significant ischemic pain immediately after the procedure. This technique has been largely abandoned.

When TAGM was first tested in the United States, a descriptive end point was created, with complete occlusion of the fibroid flow but with remaining slow flow in the uterine arteries.40 This has subsequently been described as the pruned-tree appearance, with complete distal occlusion of the uterine artery branches to the fibroids, but the main trunk of the uterine artery still patent with sluggish flow (Fig. 54.3). This has become the standard end point of embolization, and complete occlusion of the vessel by TAGM results in more severe ischemia and therefore should be avoided as TAGM packs tightly in vessels.

PVA particle, acrylamido PVA, and Polyzene-F–coated PVA hydrogel all are used with a similar end point—with near stasis. This is described as very sluggish residual flow, often with to-and-fro flow in the angled segments of the vessel and essentially complete occlusion of all portions of the fibroid feeding branches angiographically (Fig. 54.4). This more aggressive end point is suggested to ensure that these materials, which are believed to not pack as densely as TAGM, do not recanalize early after the completion of the embolization.

Periprocedural Management

Preprocedure Considerations

Beyond the usual evaluation and preparation of any patient who is to undergo a sedated angiographic procedure, there are a few potential problems that should be considered. These are important because they can help address the common issues that patients are likely to experience after embolization.

Because there is typically significant ischemic pain that occurs immediately after embolization, it is important to have a pain protocol, including patient-controlled analgesia (PCA) pump, ready for start in the angiography suite immediately after the procedure. Although a patient can be treated with intermittent dosing of intravenous narcotics during the transition to the recovery area, there can be delays in nursing response or in the initiation of the PCA pump if left to the recovery area. In any case, it is important for the interventionalist to plan the pain management protocol carefully and instruct nursing staff on the plan and orders to ensure a smooth transition of care.

Many interventionalists routinely use prophylactic antibiotics for UFE. Although there is little evidence to support their use as the risk of periprocedure infection is low, a single preoperative dose has little risk. There is no clear preference of antibiotics defined in the literature. The most important point is for the antibiotic to be given intravenously 30 to 60 minutes before the procedure. There is no evidence for continued use beyond that single preprocedure dose and there is potential harm, therefore it is not recommended.

A Foley catheter is helpful as the uterine arteries can become obscured by the contrast filling the bladder if the procedure is prolonged. It also is helpful for the first several hours while the patient is at bedrest after the procedure. Some operators choose not to use Foley catheters to reduce the chance of urinary tract infection. If used, it should be discontinued at the earliest time possible, typically within several hours after the procedure when the patient first ambulates.

There is a risk of venous thromboembolism, as will be discussed in a later section. This risk can be potentially reduced by the routine use of pneumatic compression devices and the prophylactic use of low-molecular-weight heparin in patients at high risk.

Postprocedure Pain Management

The key to a successful recovery is proper anticipation of patient problems and planning to manage them. The recovery process can be divided into two phases: in hospital and postdischarge.

Typically, patients will experience moderate to severe pain for several hours after the procedure. This is ischemic pain in the uterus and is caused at least in part by myometrial ischemia. It is known that there is occlusion of some normal uterine branches after UFE, and this results in nonperfusion temporarily to much of the deep myometrium.41 The degree of myometrial ischemia may be end point driven, although to date, there has been little study on that question. The significant ischemic pain that occurs for several hours after UFE is the first management priority.

There has been a detailed analysis of recovery after uterine embolization published by Bruno et al.42 Using data from a randomized trial comparing PVA particle and TAGM, the two most commonly used embolics currently and the end points as described in the earlier section, using a 10-point pain scale, the mean peak pain score was 3.03 in the first 24 hours, a relatively modest pain level. Eleven of 99 patients had a peak pain score of greater than 7 on that scale. This level of pain control may be attributed to the use of a standardized pain management regimen, with patients maintained on a PCA pump (in this study primarily morphine) and while being given regular intravenous doses of ketorolac every 6 hours. Supplemental doses of intravenous narcotics, either morphine or fentanyl, were used as needed. In this study, all patients were observed overnight. Nausea was a frequent additional issue, either due to the narcotics or from the procedure itself, and was managed with doses of ondansetron or promethazine as needed.

Pain management also is important after discharge home. Typically, this is a combination of around-the-clock oral nonsteroidal anti-inflammatory medications at a prescription dose and a combination oral narcotic/acetaminophen tablet taken as needed. Anti-inflammatories may be tapered after 4 to 5 days or sooner if cramping is well controlled. Typically, patients will experience cramping for 2 to 3 days and will need to limit activity during that time and for several days thereafter. Fatigue, loss of appetite, and malaise are common, and a third of patients will develop a low-grade temperature in the first week after embolization.42 These symptoms usually are self-limited and only require supportive care.

OUTCOMES

Clinical Outcomes

A substantial literature now exists documenting treatment outcomes after UFE. A PubMed search of UFE yields over 1,000 references, suggesting that the number of studies related to this topic is large. Given the limitations of space, this review of outcomes will to center on the pivotal randomized trials.

As of October 2013, there have been 37 published papers from randomized trials comparing technical aspects of UFE or comparing other therapies for fibroids with UFE. We will focus on two studies, the REST and EMMY Trials, that compare UFE primarily to hysterectomy and two that compare outcomes to myomectomy (the Fibroids of the Uterus: Myomectomy versus Embolization [FUME] Trial and a trial by Mara and coworkers from Prague). There are 9 publications from the EMMY Trial from the Netherlands, 4 from the REST Trial from the United Kingdom, 2 publications from the study of Mara and coworkers comparing UFE to myomectomy, and 1 from the FUME Trial. We will concentrate on the key publications from these studies comparing hysterectomy or myomectomy to UFE.

The EMMY Trial was a multicenter study completed in the Netherlands. There are several related publications, but two are key—the short-term results43 and the 2-year results44—and these will be reviewed here. The study included 177 patients randomly assigned to UFE (n = 88) or hysterectomy (n = 89). Short-term length of stay was shorter for UFE and there were no differences in major complications. Minor complications were more frequent with uterine embolization. There were higher readmission rates for UFE (11.1% vs. 0%, P = .003). To determine longer term outcomes, the EMMY Trial was designed to determine if uterine embolization was “not inferior” to hysterectomy, defined as at least 75% of UFE patients avoiding hysterectomy at 2 years after treatment. By the end of the initial 2 years after treatment, 24% of patients had undergone hysterectomy and the conclusion was that UFE was not inferior to hysterectomy. Both groups had similar improvements in health-related quality of life after treatment and had similar satisfaction levels with the outcomes from treatment.

The REST Trial was a multicenter study from the United Kingdom that randomized patients to either surgery (hysterectomy or myomectomy) or embolization in a ratio of 2 embolization patients to each surgery patient.45 The primary outcome measure was health-related quality of life after treatment using the SF-36. In the periprocedure period, the study found that UFE is less painful than surgery and has a shorter length of stay and a faster return to work. They found no differences in complications between the two groups. The median follow-up in the REST Trial was 32 months. They found no differences in the quality of life scores at 12 months. Both groups had significant improvement and there was no difference in satisfaction levels. Having said that, reintervention rates were much higher in UFE patients (21 for UFE vs. 1 for surgery, P < .001). Ten of these interventions occurred in the first year, presumably due to failure of symptom control, and 11 during subsequent follow-up.

The FUME Trial46 provides the best evidence of the relative effectiveness of embolization and myomectomy for controlling symptoms. One hundred sixty-three women were randomized to either myomectomy or embolization. Symptom status and quality of life were measured using the Uterine Fibroid Symptom and Health-Related Quality of Life (UFS QOL) questionnaire, a validated fibroid-specific questionnaire,47 and were compared at 1 and 2 years. Initial symptom control was excellent for both groups, although the myomectomy patients had lower mean symptom scores (fewer symptoms) at 3 months compared to the mean scores for UFE patients. The health-related quality of life scores were also poorer for the UFE group. Reinterventions trended toward greater frequency in the UFE group (14.8% vs. 4%, P = .067).

Thus, there are similar outcomes in terms of symptoms and quality of life when comparing surgery to UFE, but most studies have shown higher reintervention rates for UFE. This is balanced by the shorter recovery time, lower overall pain during recovery after UFE, and the minimally invasive nature of the procedure.

Reproductive Outcomes

Mara and coworkers from Prague48 are the only ones to date to review comparative reproductive outcomes in a randomized trial to date. In this study, 121 patients with a mean age of 32 years were randomly assigned to either myomectomy or uterine embolization. The patients were followed for 2 years and the reproductive outcomes were reported. Overall, the reproductive outcomes were better for the myomectomy group. The pregnancy rate after myomectomy was 78%, the delivery rate was 48%, and the abortion rate was 23% (compared to a pregnancy rate of 50%, delivery rate of 19%, and abortion rate of 64% for UFE). All of these differences were statistically significant. The study had some limitations in that myomectomy was recommended and performed after UFE in a third of the patients (19 of 58 patients), which delayed a trial of pregnancy in those patients and may also have imparted additional reproductive risk due to a second intervention. Regardless, based on this single trial, there appears likely that myomectomy may provide better reproductive outcomes than UFE in the short term.

A systematic review by Homer and Saridogan49 of reproductive outcomes after UFE provides additional insight. Its focus was on whether UFE imparts additional risk of early and late pregnancy complications when compared to women with fibroids that are untreated. This review summarizes all the reported pregnancies after UFE in the literature (N = 227), with controls identified from various studies. The results of this analysis demonstrate that there are increased rates of miscarriage (odds ratio [OR] = 2.8), cesarean section (OR =2.1), and postpartum hemorrhage (OR = 6.4) after UFE compared to controls. These results need to be interpreted with caution as the control groups were likely dissimilar in extent of disease, prior interventions, and age. Well-designed prospective registries might provide additional insights into pregnancy outcomes.

These studies suggest that although patients may become pregnant after UFE, the reproductive outcomes after myomectomy may be better for many patients. This presumes that the patient has not had prior interventions for fibroids and that she is at an age in which she is likely to become pregnant. Myomectomy also should be the first choice in those patients being considered for assisted reproductive technologies. On the other hand, the reproductive outcomes after a second myomectomy are uncertain and many women have extensive or large fibroids, and it often is not clear if myomectomy is feasible. For these patients, embolization may be a better choice. Each patient’s circumstance needs to be individually considered, including patient’s reproductive plans, her preferences, the extent of the fibroids, patient age, and feasibility of other therapies.

COMPLICATIONS

Overall, UFE is safe in the short-term and complications are infrequent. Due to space limitations, the focus here will be on complications specifically associated with UFE, with the assumption that the angiographic risks of this type of procedure are well-known.

Embolization-Related Complications

The embolization-related complications are rare. If the catheters or microcatheters are safely placed within the uterine arteries, then there is little likelihood that there will be a complication. Having said that, there are case reports of significant complications related to injury of adjacent structures, such as the vaginal wall, labia, bladder, and even the buttock.5055 There are several case reports in the literature reporting ischemic myometrial injury after embolization,5658 and this may result in the need for hysterectomy. However, this type of complication is rare as it was not reported in the FIBROID Registry or other large studies of complications.59,60

Ovarian dysfunction is a special case of embolization-related complication. The frequency of true ischemic injury to the ovaries is not known, but we know the frequency of amenorrhea after embolization in the FIBROID Registry was reported at 7.3%, 86% of whom were aged 45 years or older. A recent review of the impact of ovarian dysfunction by Kaump et al.61 showed that most reports of ovarian dysfunction occurred in patients older than the age of 45 years and that there was little evidence of ovarian dysfunction in those younger than 40 years of age.

Fibroid Passage and Infection

The most common late complication that occurs after uterine embolization is fibroid passage, often associated with infection.59 Although both fibroid passage and fibroid infection can occur as isolated events, often, there is a combination of both, with a spectrum of presentations ranging from minor episodes of tissue passage without infection to chronic low-grade infection and discharge to major tissue passage with substantial pain, bleeding, or infection.

In 2011, Shlansky-Goldberg reviewed his institution’s experience with fibroid expulsion and that report provides new insights into this complication.62 Of 759 patients treated, 37 (5%) had either bulk passage of a fibroid or sloughing over period of time. The mean time of fibroid expulsion was 14.8 weeks after treatment, with the range from 1.6 to 105.9 weeks. The most common presentation of women with symptomatic expulsion was bulk passage of either an entire fibroid or a major fragment, occurring in 89% (31 patients) in this series. Outcomes were generally good, with half the patients requiring no operative intervention. However, in the others, intervention was required, and in 16% (6 of 37) of those with symptomatic expulsion, hysterectomy was required.

Systemic Complications

Malaise, fatigue, and fever are common accompaniments to recovery after uterine embolization, and these are not considered complications.42 Rarely, pain can be severe and persisting and may require readmission. In this circumstance, if pain does not immediately respond to intravenous medications, a contrast-enhanced MRI should be obtained to assess for possible myometrial injury.

Venous thromboembolism is potentially among the most serious of UFE complications. This is a rare event, but pulmonary embolus has been reported in approximately 1 in 400 patients.63 It has been established that patients become temporarily hypercoagulable after UFE, similar although not as severe as the hypercoagulability that occurs after surgery.64 This predisposes to venous thrombosis. There has been one case report of death from pulmonary embolism after UFE,65 and interventionalists should consider prophylactic measures, particularly in high-risk patients, to prevent these serious outcomes.

TIPS AND TRICKS

Tips

• Complete occlusion of the uterine arteries is not necessary. Embolization should be continued until there is distal occlusion of the fibroid branches, with slow flow in the uterine arteries.

• The likelihood of fibroid expulsion can be estimated to some degree. The greater the fibroid size that has a submucosal component, the more likely it is to be expelled after embolization.

• Although it has often been said that the presence of an intrauterine device increases the risk of infection after UFE and therefore they should be removed, there is no evidence to confirm that belief and some evidence to the contrary.

• Controlling the radiation dose is important; the easiest ways to reduce are to reduce fluoroscopy frame rate to 7.5 per second or less and reduce the rate of filming to 0.5 or 1 per second. Collimation is also important.

• There is no clear advantage of trisacryl gelatin microspheres over PVA particles, the two most frequently used products that have specific clearance by the FDA.

• It is important to look for causes other than fibroids when the bleeding or pain pattern is atypical.

• Understanding the other treatments for fibroids is key to appropriately counseling patients, including the advantages and disadvantages they may have compared to UFE for that patient.

• Cervical fibroids are the one class of fibroids that are regularly not well treated with embolization.

Tricks

• If you have an assistant, bilateral femoral access with simultaneous embolization decreases procedure time and radiation exposure.

• Even when one’s routine is unilateral femoral access, consider a second femoral access when the ipsilateral femoral catheterization is difficult.

• Use microcatheters whenever there is uterine artery spasm.

• Retracting the microcatheter a centimeter or two within the uterine artery to above a kink often will relieve spasm.

• Never embolize unless the catheter tip is within the uterine artery; nonselective embolization with particulate embolic will result in injury to other pelvic structures. Also, the catheter should be well within the uterine artery and care should be taken to avoid reflux.

• It is helpful to wait several minutes at the apparent conclusion of the embolization to be sure the end point is stable.

• If an abdominal aortogram is done, it should be done at the end of the embolization. Ovarian arteries that provide supply to the fibroids at the beginning of the embolization often do not at the end of the uterine embolization.

CONCLUSION

UFE should be considered a first-line therapy for women with symptomatic uterine fibroids, with an extensive literature demonstrating its effectiveness and safety. With appropriate patient selection, technique, and periprocedural care, patients can anticipate a rapid recovery and routine to normal activity, with excellent clinical outcomes.

REFERENCES

 1. Ravina J, Herbreteau D, Ciraru-Vigneron N, et al. Arterial embolisation to treat uterine myomata. Lancet. 1995;346:671–672.

 2. American College of Obstetricians and Gynecologists. ACOG practice bulletin. Alternatives to hysterectomy in the management of leiomyomas. Obstet Gynecol. 2008;112:387–400.

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