Uterine Fibroid Embolization: Technical Approaches, Embolic Agent Selection, and Patient Outcomes

Úvod

Uterine fibroids, also known as leiomyomas or myomas, are the most common benign tumors of the female reproductive system, affecting a significant proportion of women during their reproductive years. While often asymptomatic, fibroids can cause a range of debilitating symptoms, including heavy menstrual bleeding (menorrhagia), pelvic pain or pressure, urinary frequency, constipation, and infertility. These symptoms can significantly impact a woman’s quality of life, leading many to seek treatment.

Historically, hysterectomy (surgical removal of the uterus) was the definitive treatment for symptomatic fibroids. While effective, hysterectomy is a major surgical procedure associated with significant morbidity, prolonged recovery, and the loss of fertility. Myomectomy (surgical removal of fibroids while preserving the uterus) offers a fertility-sparing alternative but is also a surgical procedure with associated risks and potential for fibroid recurrence.

Over the past two decades, uterine fibroid embolization (UFE), also known as uterine artery embolization (UAE), has emerged as a safe, effective, and minimally invasive alternative to surgery for the management of symptomatic fibroids. This image-guided procedure involves the selective occlusion of the uterine arteries, which supply blood to the fibroids. By interrupting the blood supply, UFE causes the fibroids to shrink and soften, leading to significant improvement or resolution of symptoms in the vast majority of patients.

UFE offers several advantages over traditional surgical approaches, including reduced invasiveness, shorter hospital stay, faster recovery, and preservation of the uterus. It has become a well-established treatment option, supported by extensive clinical evidence demonstrating its long-term efficacy and safety. However, successful UFE requires meticulous technique, appropriate patient selection, and careful consideration of embolic agent choice.

This comprehensive review explores the technical aspects of uterine fibroid embolization, examining patient selection criteria, procedural techniques, embolic agent selection principles, evidence-based outcomes, and potential complications. By understanding the nuances of UFE, clinicians can better counsel patients and optimize treatment strategies for women suffering from symptomatic uterine fibroids.

Zřeknutí se lékařské odpovědnosti:

Understanding Uterine Fibroids

Epidemiology and Pathophysiology

1. Prevalence: Estimated to affect 70-80% of women by age 50, though many are asymptomatic.
2. Risk Factors: African American race, early menarche, nulliparity, obesity, family history.
3. Pathogenesis: Monoclonal proliferation of smooth muscle cells, influenced by estrogen and progesterone.
4. Classification: Based on location within the uterus:
   • Submucosal: Protrude into the uterine cavity (most likely to cause heavy bleeding).
   • Intramural: Contained within the uterine wall (most common type).
   • Subserosal: Protrude from the outer surface of the uterus.
   • Pedunculated: Attached to the uterus by a stalk (submucosal or subserosal).

Klinická prezentace

Symptoms depend on fibroid size, number, and location:

1. Abnormal Uterine Bleeding: Heavy menstrual bleeding (menorrhagia), prolonged periods, intermenstrual bleeding.
2. Bulk-Related Symptoms: Pelvic pain or pressure, abdominal bloating, urinary frequency or urgency, constipation, dyspareunia (painful intercourse).
3. Reproductive Issues: Infertility, recurrent pregnancy loss, obstetric complications.

Diagnosis

1. Pelvic Examination: May reveal an enlarged, irregular uterus.
2. Transvaginal Ultrasound: Primary imaging modality for initial diagnosis and characterization.
3. Magnetic Resonance Imaging (MRI): Gold standard for detailed assessment of fibroid number, size, location, and vascularity; essential for UFE planning.
4. Hysteroscopy/Saline Infusion Sonohysterography: Evaluation of submucosal fibroids and uterine cavity.

Patient Selection for UFE

Careful patient selection is crucial for optimizing outcomes and minimizing complications.

Indikace

1. Symptomatic Uterine Fibroids: Primarily heavy menstrual bleeding and/or bulk-related symptoms.
2. Desire to Preserve Uterus: Patients who wish to avoid hysterectomy.
3. Poor Surgical Candidate: Patients with comorbidities increasing surgical risk.
4. Failed Medical Management: Patients unresponsive to or intolerant of hormonal therapies.

Kontraindikace

1. Absolutní kontraindikace:

   • Těhotenství
   • Active pelvic infection (pelvic inflammatory disease, endometritis)
   • Suspected gynecologic malignancy (uterine, cervical, ovarian)
   • Undiagnosed adnexal mass
   • Severe allergy to iodinated contrast media (unless alternative imaging used)

2. Relativní kontraindikace:

   • Desire for future pregnancy (controversial, requires careful counseling)
   • Postmenopausal status (fibroids typically regress after menopause)
   • Severe renal insufficiency (contrast load concern)
   • Uncorrectable coagulopathy
   • Large pedunculated subserosal fibroids with narrow stalk (risk of detachment)
   • Predominantly adenomyosis (UFE less effective)
   • Prior pelvic radiation

Pre-Procedure Evaluation

1. Comprehensive Gynecologic Assessment: Including Pap smear, endometrial biopsy (if indicated to rule out malignancy), infection screening.
2. Pelvic MRI: Essential for:
   • Confirming diagnosis and excluding alternative pathology.
   • Mapping fibroid number, size, location, and enhancement characteristics.
   • Identifying ovarian artery supply to fibroids (present in 5-10% of cases).
   • Assessing for adenomyosis.
   • Guiding procedural planning.
3. Laboratory Tests: Complete blood count (assess anemia), coagulation profile, renal function tests.
4. Patient Counseling: Detailed discussion of risks, benefits, alternatives, expected outcomes, potential impact on fertility, and post-procedure course.

Technical Aspects of UFE Procedure

UFE is typically performed by an interventional radiologist in an angiography suite.

Vascular Access

1. Femoral Artery Access: Most common approach.
   • Unilateral (typically right common femoral artery) or bilateral access.
   • Requires crossover technique for contralateral uterine artery catheterization if unilateral access used.
2. Radial Artery Access: Emerging alternative.
   • Potential benefits: Reduced access site complications, faster ambulation.
   • Requires longer catheters and specific operator expertise.

Catheterization Techniques

1. Aortography/Pelvic Angiography: Initial roadmap to identify uterine arteries and potential collateral supply (e.g., ovarian arteries).
2. Selective Internal Iliac Artery Catheterization: Using a base catheter (e.g., 4-5 Fr Simmons, Cobra, or vertebral catheter).
3. Selective Uterine Artery Catheterization: Using a microcatheter (e.g., 2.4-2.8 Fr) coaxially through the base catheter.
   • Goal: Catheterize uterine artery distal to cervicovaginal branches to minimize non-target embolization.
   • Bilateral catheterization is standard for optimal results.

Embolization Technique

1. Embolic Agent Preparation: Suspension of particles in contrast medium.
2. Injection Method: Slow, pulsatile injection under fluoroscopic guidance.
3. Angiographic Endpoint: Near-stasis or