Uterine Artery Embolisation

Description

Uterine Artery Embolisation (UAE) is a percutaneous, image-guided endovascular procedure that targets the uterine arteries to treat symptomatic uterine leiomyomas (fibroids). The procedure induces ischaemia within the fibroids by occluding their arterial blood supply, leading to cellular apoptosis and subsequent volume reduction. UAE is a viable alternative to surgical interventions like hysterectomy or myomectomy, particularly for patients seeking uterine conservation.

Indications

• Symptomatic Uterine Fibroids: UAE is primarily indicated for women with symptomatic fibroids, which may present with menorrhagia, pelvic pain, bulk-related symptoms, or compressive effects on adjacent structures.
• Adenomyosis: UAE is also applicable in cases of adenomyosis, especially when surgical management is contraindicated or declined by the patient.
• Uterine Preservation: It is an option for patients who wish to avoid the morbidity associated with hysterectomy or maintain fertility potential, albeit with some limitations.

Contraindications

Absolute

• Pregnancy: Embolisation during pregnancy is contraindicated due to potential harm to the fetus and disruption of placental blood flow.
• Active Pelvic Infection: Ongoing pelvic inflammatory disease precludes UAE as it can exacerbate the infection and complicate recovery.
• Suspected Malignancy: UAE is contraindicated if there is a suspicion of uterine malignancy, as embolisation could obscure diagnosis and delay appropriate oncological treatment.

Relative

• Future Fertility Considerations: Although some women can conceive after UAE, the impact on fertility is not fully predictable, making alternative treatments preferable for women with strong future fertility desires.
• Severe Contrast Media Allergy: Patients with significant hypersensitivity to iodinated contrast agents may require alternative imaging techniques or pre-procedural desensitisation protocols.
• Extremely Large or Numerous Fibroids: The efficacy of UAE may be reduced in patients with very large or numerous fibroids, possibly necessitating supplementary procedures or alternative treatments.

Risks

• Post-Embolisation Syndrome (PES): Characterised by transient pelvic pain, low-grade fever, nausea, and malaise. Occurs sin most patients within 24-48 hours post-procedure. Management involves NSAIDs, antiemetics, and hydration, with most symptoms resolving within a week.
• Infection: Uterine or pelvic infection post-UAE is rare but can occur, necessitating the use of prophylactic antibiotics and prompt treatment with broad-spectrum antibiotics if signs of infection arise.
• Non-Target Embolisation: Unintentional embolisation of arteries supplying non-uterine pelvic structures (e.g., bladder, rectum) can lead to ischaemic complications. This risk is mitigated by precise catheter positioning and real-time fluoroscopic monitoring during embolisation.
• Ovarian Failure: UAE may inadvertently affect ovarian blood supply, particularly in perimenopausal women, leading to premature ovarian insufficiency or amenorrhoea.
• Uterine Necrosis: Severe ischaemia, although rare, can lead to uterine necrosis, necessitating emergent hysterectomy.

Preprocedural Patient Preparation

• Imaging: A detailed pre-procedural evaluation with pelvic MRI or contrast-enhanced ultrasound is essential to characterise fibroid number, size, and vascularity, as well as to rule out concurrent pathologies.
• Laboratory Tests:
  • CBC: Ensures adequate hemoglobin levels and screens for anemia.
  • Coagulation Profile (INR, PT, PTT): Critical to evaluate for coagulopathy; correct any abnormalities to minimise bleeding risk.
  • Renal Function Tests: Serum creatinine should be checked to assess renal function and the safety of contrast administration.
• Anticoagulant Management:
  • Warfarin: Discontinued 3-5 days pre-procedure, with normalisation of INR prior to UAE.
  • DOACs: Held for 24-48 hours before the procedure depending on renal clearance.
  • Aspirin/NSAIDs: Discontinued 5-7 days prior to minimise bleeding risk.

Relevant Anatomy

The uterine arteries, typically arising from the anterior division of the internal iliac arteries, supply the uterus and adjacent structures. They course through the cardinal ligaments toward the uterus, where they bifurcate into ascending and descending branches, extensively anastomosing with the ovarian arteries. Detailed knowledge of uterine artery anatomy, including potential collateral vessels, is imperative for effective and safe embolisation. Non-target embolisation risks are minimised by precise catheter placement and thorough angiographic evaluation before particle delivery.

Equipment Required

• Vascular Access Sheath: Typically a 5-Fr or 6-Fr introducer sheath.
• Guidewires: A 0.035-inch hydrophilic wire, such as a Benson or Glidewire, for initial access, and a 0.018-inch microwire for selective catheterisation.
• Catheters: A 4-Fr or 5-Fr Cobra, Roberts Uterine, or Simmons catheter for selective uterine artery engagement.
• Embolic Agents: Non-spherical polyvinyl alcohol (PVA) particles (300-500 µm), tris-acryl gelatin microspheres, or calibrated microspheres are utilised to achieve permanent arterial occlusion.
• Imaging Equipment: High-resolution fluoroscopy with digital subtraction angiography (DSA) for precise visualisation of uterine arterial anatomy and embolisation.

Procedure

1. Vascular Access: Femoral artery access is typically obtained, though radial access can be considered depending on operator preference and patient anatomy.
2. Selective Catheterisation: The uterine arteries are selectively catheterised under fluoroscopic guidance. Both left and right uterine arteries are embolised sequentially.
3. Angiography: Pre-embolisation angiography confirms the vascular anatomy and identifies any anatomical variations or collateral vessels.
4. Embolisation: Embolic agents are injected slowly under fluoroscopy until arterial flow to the fibroids ceases. Careful monitoring ensures avoidance of non-target embolisation.
5. Completion Angiography: Post-embolisation angiography confirms adequate embolisation of the target vessels and checks for collateral perfusion to adjacent structures.
6. Sheath Removal and Hemostasis: The sheath is removed, and hemostasis is achieved either through manual compression or with a vascular closure device.

Postprocedural Management

• Analgesia: Administer NSAIDs and opioids as needed for pain control. Patient-controlled analgesia (PCA) can be considered for severe pain.
• Antibiotics: Continue prophylactic antibiotics for 24-48 hours to reduce the risk of infection.
• Observation: Patients are monitored for 4-6 hours post-procedure for any immediate complications, with attention to vital signs, pain, and signs of non-target embolisation.
• Follow-Up Imaging: MRI or ultrasound should be performed at 3-6 months post-procedure to evaluate fibroid response and overall uterine health.
• Recovery: Most patients can resume normal activities within 1-2 weeks, with a gradual return to full physical activity based on symptom resolution.

Postprocedural Image Findings

• The presence of branching, serpiginous, linear distribution of gas within the uterine arteries is an expected finding that may be seen as early as 1 month following uterine artery embolisation. It is thought to be the result of gas filling potential spaces left by tissue infarction/desiccation. This pattern rarely represents infection.
• Globular gas distribution more likely represents infection (pyomyoma).

Therapeutic Effects

• Symptomatic Relief: UAE typically results in a significant reduction in fibroid-related symptoms, including menorrhagia, pelvic pain, and bulk symptoms.
• Fibroid Size Reduction: Marked reduction in fibroid volume is usually observed within 3-6 months post-procedure, contributing to symptomatic improvement.
• Patient Satisfaction: UAE has a high satisfaction rate among patients, particularly those seeking an alternative to hysterectomy with preservation of uterine anatomy.

References

1. Spies JB, Spector A, Roth AR, Baker CM, Mauro L, Murphy-Skrzyniarz KM. Complications after uterine artery embolization for leiomyomas. Obstetrics & Gynecology. 2002;100(5 Pt 1):873-880.
2. de Bruijn AM, Ankum WM, Reekers JA, Birnie E, van der Kooij SM, Volkers NA, Hehenkamp WJK. Uterine artery embolization vs hysterectomy in the treatment of symptomatic uterine fibroids: 5-year outcome from the randomized EMMY trial. American Journal of Obstetrics and Gynecology. 2016;215(6):745.e1-745.e12.
3. Hirst A, Dutton S, Wu O, et al. A multi-centre retrospective cohort study comparing the efficacy and complications of uterine artery embolization and surgical treatment for symptomatic uterine fibroids (REST trial). Health Technology Assessment. 2008;12(5):1-248.
4. Worthington-Kirsch RL, Popky GL, Hutchins FL Jr. Uterine artery embolization for the management of leiomyomas: quality-of-life assessment and clinical response. Radiology. 1998;208(3):625-629.