What are the steps for an abdominal aortic aneurysm (AAA) endovascular repair?

Step-by-Step Guide for Endovascular Abdominal Aortic Aneurysm (AAA) Repair

Endovascular aneurysm repair (EVAR) is the preferred approach for AAA repair in patients with suitable anatomy and reasonable life expectancy (>2 years), offering reduced perioperative mortality (<1%) compared to open repair. 1

Pre-Procedure Assessment

Patient Selection Criteria

• Elective repair indicated when:
  • AAA diameter ≥55 mm in men or ≥50 mm in women 2
  • Saccular aneurysm ≥45 mm 2
  • Aneurysm growth ≥5 mm in 6 months or ≥10 mm per year 2
• Contraindications:
  • Limited life expectancy (<2 years) 2
  • Unsuitable anatomy for EVAR

Anatomical Assessment

• CT angiography is the primary imaging modality for preoperative planning 2
• Key anatomical considerations:
  • Proximal neck morphology: length >10-15 mm, diameter <30 mm 2
  • Neck angulation (<60°) 2
  • Presence of mural thrombus/calcification (<90% circumference) 2
  • Iliac access vessel diameter and tortuosity 2
  • Evaluate for concomitant femoro-popliteal aneurysms with DUS 2

Procedural Steps for EVAR

1. Pre-Procedure Preparation

• Administer appropriate prophylactic antibiotics
• Position patient supine on angiography table
• Prepare and drape bilateral groins for femoral access
• Establish appropriate anesthesia (general or local with sedation)

2. Vascular Access

• Obtain bilateral femoral artery access via:
  • Surgical cutdown approach, or
  • Percutaneous approach with closure devices
• Place vascular sheaths in both femoral arteries
• Administer systemic heparin to achieve anticoagulation

3. Initial Angiography

• Perform diagnostic angiography with calibrated catheter
• Confirm renal artery position and other critical branches
• Verify measurements from pre-procedure imaging

4. Main Body Deployment

• Advance the main body delivery system through the larger iliac vessel
• Position the device precisely below the renal arteries
• Partially deploy the proximal portion of the main body
• Confirm position with angiography before complete deployment
• Deploy the main body while maintaining position

5. Contralateral Limb Cannulation

• Cannulate the contralateral gate of the main body from the contralateral access
• Confirm wire position in the main body with angiography
• Advance and deploy the contralateral limb

6. Ipsilateral Limb Deployment

• Advance and deploy the ipsilateral limb extension if needed

7. Balloon Angioplasty

• Perform balloon angioplasty at:
  • Proximal attachment site
  • Overlap zones between components
  • Distal attachment sites

8. Completion Angiography

• Perform final angiography to:
  • Confirm exclusion of the aneurysm sac
  • Verify patency of renal and hypogastric arteries
  • Check for presence of endoleaks
  • Evaluate distal runoff

9. Closure

• Remove delivery systems and sheaths
• Close access sites (suture for cutdown, closure devices for percutaneous)
• Apply sterile dressings

Post-Procedure Management

Immediate Post-Procedure Care

• Monitor vital signs and access sites
• Assess for signs of complications (limb ischemia, renal dysfunction)
• Maintain appropriate hydration to prevent contrast nephropathy

Surveillance Protocol

• First post-procedure imaging at 1 month 1
• Follow-up imaging at 12 months, then yearly thereafter 1
• CT angiography is the preferred surveillance modality 2

Potential Complications and Management

Endoleaks

• Five types of endoleaks can occur 2:
  • Type I: Seal failure at attachment sites (requires immediate correction)
  • Type II: Retrograde flow from branch vessels (observe if sac stable)
  • Type III: Graft defect or component separation (requires immediate correction)
  • Type IV: Graft porosity (usually resolves spontaneously)
  • Type V: Endotension (requires close monitoring)

Other Complications

• Access site complications (hematoma, pseudoaneurysm)
• Limb occlusion or stenosis
• Renal dysfunction
• Graft migration
• Aneurysm sac enlargement despite EVAR

Technical Considerations

Device Selection

• Choose appropriate device based on:
  • Anatomical measurements
  • Need for suprarenal vs. infrarenal fixation 2
  • For complex anatomy, consider fenestrated or branched endografts 2

Common Pitfalls to Avoid

• Underestimating neck angulation or thrombus burden
• Inaccurate sizing of components
• Inadequate post-EVAR surveillance leading to missed endoleaks 1
• Performing repair in patients with limited life expectancy 2

EVAR has transformed AAA management with lower perioperative morbidity and mortality compared to open repair, but requires meticulous planning, appropriate patient selection, and lifelong surveillance to ensure long-term success.