Uterine artery embolization

Uterine artery embolization (UAE) is an interventional radiological technique to decrease the arterial supply to the uterus and is performed for various reasons.

History

Uterine artery embolization has been practised for more than 20 years for controlling post-partum hemorrhage.

The technique was first reported as an effective intervention for fibroids in 1995 when Ravina et al noted that several women with symptomatic leiomyomata who underwent uterine artery embolization as a pre-hysterectomy treatment had significant clinical improvement to an extent that hysterectomy was no longer required.

It is now estimated that more than 100,000 UAE procedures have been performed for the treatment of fibroids.

Indications

• uterine fibroids (intramural, submucosal, and subserosal)

  • menorrhagia 

  • pelvic pain and pressure/fullness

  • mass effect symptoms such as urinary frequency, bladder outlet obstruction and hydronephrosis due to ureteric compression

  • fibroids with otherwise undiagnosed infertility

  • as a preoperative technique to decrease the size of large fibroids

• dysfunctional uterine bleeding

• adenomyosis

• post-partum hemorrhage

• other less common indications include

  • uterine artery pseudoaneurysm(s)

  • uterine AVM: trauma, post curettage

  • if active extravasation of contrast is detected during angiography for another reason (post-trauma) 

Patients with fibroids, and their related problems, probably present the largest group who is most able to benefit from uterine artery embolization. Presently people with multiple and/or large symptomatic uterine fibroids traditionally undergo total abdominal, vaginal or laparoscopic-assisted hysterectomies around the world. The figure in the United States is about 60,000 hysterectomies per year. In less developed and more populous countries like India, the numbers may be even higher. There is an increasing need for minimally alternatives for uterine fibroids and dysfunctional bleeding.

Contraindications

• contraindications to angiography

  • severe anaphylactoid reaction to contrast media

  • uncorrectable coagulopathy

  • severe renal insufficiency

• current pregnancy

• active pelvic infection

• connective tissue disease (relative)

• prior surgery with adhesions (relative)

In addition, many gynecology societal guidelines do not recommend performing UAE on women who maintain a future desire for pregnancy. Exceptions to this may include women who have severe anemia or symptoms associated with fibroids, have failed conservative measures and have contraindications to surgery or those who consent to UAE within an approved research protocol. However, recent studies have shown that fertility and miscarriage rates after uterine artery embolization for fibroids are likely similar to the age-matched general population¹¹.

Procedure

Preprocedural evaluation

• a thorough gynecological history and examination covering the patient's symptoms and goals of treatment

• pelvic ultrasound and MRI

• up-to-date cervical screening

• consider endometrial biopsy if there are concerning clinical or imaging features

• relevant history of other medical problems

• allergies

Equipment

Catheter selection

Any catheter suitable for contralateral and ipsilateral uterine artery cannulation 

• Roberts uterine catheter (RUC): commonly used selective catheter for pelvic angiography

• Cobra glidecath: can also be used

• right internal mammary catheter: may be used, but less common

• microcatheters may be used to cannulate smaller caliber arteries

Embolic agents

The type of embolic agent selected will depend on the indication. 

• fibroids and adenomyosis

  • PVA (typically 300 - 500 or 500 to 700 µm)

  • Embosphere^® microspheres

• postpartum hemorrhage

  • gel foam slurry

  • n-butyl-cyanoacrylate (glue)

Technique

The approach is dependent on operator preference.

Femoral access

The contralateral internal iliac artery is selected. The uterine artery is a branch of its anterior division and has a distinctive radiographic appearance. Care is taken to avoid cervical and vaginal branches, this is usually avoided by selective catheterization of the uterine artery distal to the origin of these branches.

The ipsilateral uterine artery is selected, commonly by formation of a Waltman loop, and subsequent embolization performed.

Embolization endpoint is diminished forward flow or near-stasis of the main uterine artery trunk.

The ovarian arteries and inferior mesenteric artery may also be interrogated and if fibroid vascularity is detected these may also be embolized.  

Brachial or radial access

This is typically performed via the left upper limb. In general, this technique allows for easier uterine artery selection, however, it presents challenges regarding catheter length and there is a small risk of stroke as the catheter crosses the origin of the left vertebral artery.

Peri-procedural care

• IV sedation is commonly given by the treating interventional radiologist or anesthetic team

• patients may be required to stay in hospital overnight to ensure adequate pain relief

• analgesia

  • local anesthesia

    • hypogastric nerve block

    • intra-arterial local anesthetic injection has been described ¹²

• IV fluids

• antiemetics

• antibiotics

Intravenous fluids, analgesia, antiemetics and antibiotics need to be continued during the postprocedural period.

Complications

• angiography complications

  • ​post-embolization syndrome

  • uterine artery dissection

• sepsis is a rare but serious complication and can be difficult to differentiate from post embolization syndrome.

• vaginal expulsion of fibroid tissue

• fibroid fragment retention

• pregnancy outcomes are uncertain after uterine artery embolization

Outcomes 

For post-partum bleeding

• prevents the need for emergency hysterectomy

• retain fertility after UAE for postpartum hemorrhage (PPH) compared to hysterectomy

For fibroids

• menorrhagia/dysmenorrhea and metrorrhagia improve in 70-95% of cases

• shorter hospital stay and recovery period that hysterectomy and myomectomy

• hospital stay is rarely >48 hours

• patients are often back to work within 10 days

• no post laparotomy complications

• mean uterine volume reduction by 26-59%

• fibroid volume reduction by 40-75% (after 6-12 months)

• the overall complication rate is approximately 10% for minor complications, with major complications at 1.5%

• low rate of uterine infection as a complication (<2.5%) and very low rate of infection requiring hysterectomy (<0.7%) ¹³

In a study of follow up two and four years after uterine artery embolization or myomectomy, women with symptomatic uterine fibroids were likely to have mildly better health quality of life results with myomectomy than uterine artery embolization at two years, but equivalent outcome at four years ^10,14.

For adenomyosis

In studies of follow up after uterine artery embolization for adenomyosis, 74-82% of women with symptomatic adenomyosis had sustained improvement in quality of life scores and avoided hysterectomy ¹⁶.

Current recommendations

• American College of Obstetrics and Gynecology (ACOG) 2021 Practice Bulletin: UAE is recommended as an interventional procedure for the treatment of uterine leiomyomas in patients who desire uterine preservation and are counseled about the limited available data on reproductive outcomes ⁹

• NICE (UK) uterine artery embolization for fibroids 2010: UAE is efficacious for symptom relief in the short and medium term for a substantial proportion of patients ¹⁵

See also

• uterine artery embolization: MRI assessment