UTERINE FIBROID EMBOLIZATION

Uterine Fibroid Embolization: 
Nonsurgical Treatment for Symptomatic Fibroids
Jie Mao, M.D.

Figure 1.  Types of Fibroids

Fibroids are classified based on their location in the uterine wall. Submucous (or submucosal) fibroids occur just under the endometrial lining of the uterine cavity. Intramural fibroids occur in the muscular wall. Subserosal fibroids occur under the outside covering of the uterus. As fibroids enlarge, the distinction between the types becomes blurred.
Pedunculated fibroids (not shown) occur on a stalk, project from the surface of the uterus, and can be confused with ovarian masses. They can project from the inner lining of the uterus and even extend through the cervix.

Uterine fibroids, also known as leiomyomas, are benign smooth muscle tumors that arise from the uterine wall (Figure 1 and 2). They are the most common tumor of the female genital tract and affect 20-40% of all women of childbearing age.  Approximately 60-90% of all uterine fibroids are asymptomatic (1). Symptoms tend to develop in women between 30-40 years of age, and often increase in the perimenopausal period.  Clinical manifestations include dysfunctional uterine bleeding, pelvic pain, pelvic pressure, abdominal distention, urinary frequency, constipation, and infertility.

Interventional Radiologists have been successfully applying uterine artery embolization (UAE) techniques to control life threatening uterine hemorrhage after childbirth for over 20 years.  In the last 10 years, UAE has been increasingly utilized in the management of symptomatic fibroids.  The procedure is called uterine fibroid embolization (UFE). 

The Technique:

The procedure takes from 60-90 minutes and is performed under conscious sedation with local anesthetic. An arteriogram is performed to map the pelvic vascular anatomy through the femoral artery (although other vascular approaches are possible). The catheter is advanced into the uterine artery where small particles of polyvinyl alcohol (PVA) are deployed until the blood supply to the fibroid is occluded (Figure 3). The same approach is applied to the opposite uterine artery, usually from a single catheter insertion site. Most patients are observed for 23 hours then discharged home.


Figure 2. Uterine Fibroid Embolization

2A:  Right iliac angiogram shows extensive arterial vascularity from the internal iliac artery to the midline of the pelvis, towards the uterus, consistent with an enlarged fibroid uterus.
2B:  Selective catheterization using a microcatheter of the right uterine artery, showing that it is the main source of the vascular blush in the uterus.
2C:  Complete embolization of the uterine artery to stasis.

Results:

Technically both uterine arteries can be successfully embolized in >98% of patients (Figure 4). Average uterine volume is reduced by ~50% with individual fibroid shrinkage between 40-70% (by MRI). Abnormal uterine bleeding resolves in 85-90% by the second menstrual cycle and bulk-related symptoms are controlled in 80-90% within the first 6-8 weeks.  5% of the patients may not experience significant symptom relief due to development of collateral flow that keeps the fibroids vascularized, and the development of new fibroids may lead to symptom recurrence (3).  These patients are candidates for retreatment and have success rates similar to untreated patients.

Selection Criteria:

  • Premenopausal women with symptomatic uterine fibroids without other etiology for their symptoms (adenomyosis, endometriosis, or endometrial cancer).
  • Poor operative candidates or a desire to avoid surgery.
  • Women who have completed childbearing.  There is a 1% chance of premature ovarian failure in premenopausal women (13).
  • <18 weeks gestational size uterus.  Larger uteri may have < 50% reduction in volume which may be inadequate for symptom relief (4).
  • Fibroids that are growing in response to hormone replacement therapy can be considered for UFE (4).

Contraindications:



  		•

    Figure 3. 

    Pelvic MRI before (A) and after (B) embolization, showing decrease in size of the dominant fibroid and less mass effect in the pelvis.
    Pregnant
  • Endometrial cancer
  • Active infection
  • Presence of an IUD
  • History of severe allergic reaction to x-ray contrast
  • Patients with renal insufficiency (relative contraindication)

Post-procedure:

Almost all patients develop pelvic pain for the first 6-10 hours post-procedure.  Cramping that persists for a few days is known as the post embolization syndrome and is usually well controlled with NSAIDs (motrin) and oral narcotics. Readmission for pain control during the first week has been reported to occur at rates of 0-9% (10). The majority of patients return to their usual activities in 7-10 days (1). Spotting or discharge is not uncommon after the procedure and resolves spontaneously.
In 5% of cases a submucosal fibroid may detach from the uterine wall and pass out the vagina. Fibroid expulsion can occur days to several months after the procedure (1). If the fibroid is large it may fail to pass requiring assisted removal by a gynecologist.

Complications:

Major complications as a result of UAE are rare (<1%) and include uterine ischemia, amenorrhea, infection, sepsis, pulmonary emoblism and death.  Suspicion of infection has prompted hysterectomy on occasion (5).  Uterine necrosis is an extremely rare occurrence (6).  Amenorrhea is typically transient, but persistent amenorrhea can occur and appears to be age-related. The incidence is 1-2% in patients < 45 years old and 5-10% inpatients > 45 years old (4) (9). As of June 2003 30,000 procedures have been performed worldwide.  There have been three deaths reported within 30 days of UAE, two from uterine infection with sepsis and one from massive pulmonary embolism (4).
Minor complications are those common to any angiographic procedure.  These include minor contrast reactions, bleeding at groin puncture site, and vessel damage that may necessitate further intervention.

Figure 4. 

Schematic diagram of uterine artery embolization procedure, showing a microcatheter placed in the right uterine artery, delivering embolization particles (white, round beads).

Cost:

Two recent cost studies from a single institution found that UAE compares favorably with hysterectomy and myomectomy.  The hospital cost for UAE was $3080. Hysterectomy ranged from $3100- $4900 depending on the type of procedure performed, and the cost for myomectomy was $5597 (11).  These studies failed to include the indirect costs of lost working days which are significantly lower in UAE patients than those receiving surgical treatment.

Conclusion:

UFE is a safe and effective therapy when compared to traditional hysterectomy or myomectomy. UAE necessitates a shorter hospital stay, results in fewer major complications, treats all existing fibroids, has virtually no blood loss or need for transfusion, preserves fertility and is cost effective (11, 12). Using today’s methods, it is associated with minimal post procedural pain.
Furthermore, there has been a high level (~85%) of patient satisfaction with UAE as measured by significant improvement in quality of life measures (2).  In 2004 the American College of Obstetrics and Gynecology (OB/GYN) issued an Opinion Statement endorsing UAE as a viable treatment option for women with symptomatic fibroids.  Specifically they recommended a multi-disciplinary approach between Interventional Radiology and OB/GYN to promote optimal outcomes for patients with symptomatic fibroids.  UFE should be considered for patients with symptomatic fibroids who desire to seek uterine preserving methods of treatment.

References:

  1. Pelage Jp, Le Dref O, Jacob D, et al.  Uterine artery embolization:  anatomical and technical considerations, indications, results, and complications.  J Radiol 2000; 81:1863-1872
  1.  Pron, Gaylene et al.  Tolerance, hospital stay, and recovery after uterine artery embolization for fibroids:  The Ontario Uterine Fibroid Embolization Trial.  J Vasc Interv Radiol 2003; 14:1234-1250
  2.  Pron, Gaylene et al.  The Ontario Uterine Fibroid Embolization Trial. Part 2.  Uterine fibroid reduction and symptom relief after uterine artery embolization for fibroids.  Fertility and Sterility Jan. 2003 Vol. 79 No.1 pp 120-127
  3. Hovsepian, David et al.  Quality Improvement Guidelines for Uterine Artery Embolization for Symptomatic Leiomyomata.  J Vasc Interv Radiol 2004; 15:535-542
  4. Vashisht A, Studd J, Carey A, Burn P.  Fatal septicaemia after fibroid embolization.  Lancet 1999; 354:307-308
  5. Godfrey CD, Zbella EA.  Uterine necrosis after uterine artery embolization for leiomyoma.  Obstet Gynecol 2001; 98:950-952
  6. Worthington-Kirsch R, Hutchins F, Berkowitz R.  Interstitial gas after uterine artery embolization:  a benign finding.  J Intervent Radiiol 1999; 14:181-185
  7. Nott, V, Reidy J, Forman R, Braude P.  Complications of fibroid embolization.  Min Invas Ther Allied Technol 1999; 8:424-424
  8. Alumad A, Qadan L, Hassan N, Najarian K.  Uterine artery embolization treatment of uterine fibroids:  Effect on ovarian function in younger women.  J Vasc Interv Radiol 2002; 13:1017-1020
  9. Andrews RT, Spies JB, Sacks D, et al.  Standards of Practics:  Patient Care and Uterine Artery Embolization for Leiomyomata.  J Vasc Interv Radiol 2004; 15:115-120
  10. Baker CM, Winkel CA, Subramanian S, Spies JB.  Estimated costs for uterine artery embolization and abdominal myomectomy for uterine leiomyomata:  A comparative study at a single institution.  J Vasc Interv Radiol 2002; 13:1207-1210
  11.  Pinto I, Chimeno P, Romo A, et al.  Uterine fibroids:  Uterine artery embolization versus abdominal hysterectomy for treatment—A prospective, randomized, and controlled clinical trial.  Radiology 2003; 226:425-431
  12. Ravina JH, Vigeron NC, Aymard A, Dref OL, Merland JJ.  Pregnancy after embolization of uterine myoma:  report of 12 cases.  Fertility and Sterility Vol 73 No. 6 June 2000 pp 1241-1244
  13. Banovac F, Ascher SM, Jones DA, Black MD, Smith JC, Spies, JB.  Magnetic resonance imaging outcome after uterine artery embolization for leiomyomata with use of Tris-acryl Gelatin Microspheres.  J Vasc Interv Radiol 2002, 13:681-688