What is the treatment for a slightly increased right common iliac artery (RIA) dissection from 16 mm to 18 mm?

Management of Right Common Iliac Artery Dissection with Slight Size Increase

For a right common iliac artery dissection that has slightly increased from 16mm to 18mm in size, surveillance imaging with continued medical management is recommended as the primary approach, with intervention reserved for symptomatic progression, rapid growth, or when the diameter reaches ≥3.5cm.

Assessment and Risk Stratification

The management of iliac artery dissections requires careful consideration of:

• Current size (18mm)
• Growth rate (2mm increase)
• Presence of symptoms
• Risk of progression or rupture

Size Considerations

• According to the American College of Cardiology/American Heart Association guidelines, common iliac artery aneurysms typically warrant elective repair when they reach ≥3.5cm 1
• The current 18mm size is below this threshold for intervention
• However, the 18mm diameter is clinically significant as studies show that common iliac arteries ≥18mm in diameter have:
  • Higher rates of type Ib endoleaks (7.2% vs 3.2%)
  • Increased late reinterventions (19% vs 11.8%)
  • Higher odds of composite EVAR failure (OR 1.8) 2

Recommended Management Approach

Immediate Management

1. Medical therapy:

   • Antiplatelet therapy (rated 8/9 for appropriateness in iliac artery disease) 2
   • Blood pressure control
   • Lipid management
   • Smoking cessation if applicable

2. Imaging surveillance:

   • CT angiography within 1 month to establish a new baseline 2
   • Follow-up imaging at 6-12 months if stable 2
   • Consider MRI as an alternative to reduce radiation exposure 2

Indications for Intervention

Intervention should be considered if:

• Diameter reaches ≥3.5cm 1
• Rapid growth (>5mm in 6 months)
• Development of symptoms (claudication, pain)
• Evidence of distal embolization
• Progression of dissection

Intervention Options (if needed)

If intervention becomes necessary:

• Endovascular approach: Preferred for suitable anatomy

  • Stenting is effective as primary therapy for common iliac artery lesions (Level of Evidence: B) 2
  • Consider preservation of hypogastric artery flow to prevent pelvic ischemia 1

• Surgical approach: Reserved for cases unsuitable for endovascular repair or failed endovascular treatment

Monitoring and Follow-up

• Regular clinical assessment for symptoms of claudication or pain
• Surveillance imaging protocol:
  • CT or MRI at 1 month, 12 months, and annually thereafter if stable 2
  • More frequent imaging if:
    • Growth rate accelerates
    • New symptoms develop
    • Changes in hemodynamic status occur

Potential Complications to Monitor

• Progression of dissection
• Aneurysmal degeneration
• Thrombosis
• Distal embolization
• Rupture (rare at current size)

The slight increase from 16mm to 18mm warrants close monitoring but not immediate intervention, as the current size remains well below the 3.5cm threshold for elective repair. However, the 18mm diameter does place this patient in a higher risk category for future complications if further growth occurs.