How often should surveillance be performed for a growing endoleak (Endoleak, type of vascular leakage)?

Surveillance Protocol for Growing Endoleaks After EVAR/TEVAR

For a growing endoleak, surveillance imaging should be performed every 6 months for at least 24 months, with consideration for more frequent imaging if the aneurysm sac expands ≥10 mm. 1

Initial Assessment and Classification

Growing endoleaks require careful monitoring as they can lead to aneurysm sac expansion and potential rupture. The surveillance frequency depends on:

• Type of endoleak
• Rate of aneurysm sac growth
• Size of expansion

Endoleak Types and Risk Stratification:

• Type I and III endoleaks: Highest rupture risk (7.5% at 2 years and 8.9% at 1 year respectively) 2

  • Require immediate correction with new endovascular procedure 1

• Type II endoleaks: Most common (25% of patients)

  • May seal spontaneously in ~50% of cases 1
  • Require intervention if associated with significant sac expansion (≥10 mm) 1

• Type IV: Rare with modern devices, typically benign 1

• Type V (endotension): Causes sac expansion without visible endoleak 1

Surveillance Protocol Based on Sac Growth

For Aneurysm Sac Growth ≥10 mm:

• Perform CCT (cardiovascular computed tomography) or DUS/CEUS (duplex ultrasound/contrast-enhanced ultrasound) 1
• Consider embolization if feasible (Class IIa recommendation) 1
• If embolization not feasible or unsuccessful, consider open surgery 1

For Aneurysm Sac Growth <10 mm or Shrinking:

• Surveillance every 6 months for 24 months 1
• Then annual surveillance with CCT or DUS/CEUS for the first 5 years 1

Imaging Modalities

• CCT with contrast: Gold standard, especially for TEVAR 1

  • Limitations: Radiation exposure, contrast nephrotoxicity 1

• DUS/CEUS: 95% accurate for measuring aneurysm sac diameter and 100% specific for Type I and III endoleaks 1, 3

  • Limitations: Less reliable for Type II endoleaks, limited ability to detect stent migration or fracture 1
  • May be superior to CT for determining need for intervention 4

• MRI: High diagnostic accuracy for endoleaks but requires plain radiograph to assess stent fracture 1, 3

Long-term Surveillance

• After the initial intensive monitoring period (24 months):
  • Continue annual surveillance with CCT or DUS/CEUS for the first 5 years 1
  • For stable cases after 5 years: CCT or DUS/CEUS every 5 years 1, 2
  • For persistent endoleaks: Continue more frequent surveillance 5

Clinical Pitfalls and Caveats

• Persistent type II endoleaks (>6 months) are associated with adverse outcomes including:

  • Increased aneurysm sac growth (OR 25.9)
  • Higher reintervention rates (OR 19.0)
  • Increased rupture risk 5

• Chronic anticoagulation is a risk factor for endoleak persistence, late conversion surgery, and mortality 1

• Stent graft complications (fracture and migration) occur in 3-4% by 4 years postoperatively 1, 3

• Late rupture risk remains >5% through 8 years of follow-up after EVAR 1, 3

Special Considerations

• For TEVAR, CCT is the preferred imaging technique since DUS/CEUS does not permit correct evaluation of the thoracic aorta 1

• In renally impaired patients, consider non-contrast CCT combined with DUS as an alternative surveillance strategy 1

• Type II endoleaks with sac expansion require a more aggressive approach, as up to 90% of type II endoleaks without sac growth resolve spontaneously 2, 6