What is the role of endovascular repair in treating aortic aneurysm?

Endovascular Repair for Aortic Aneurysm

Endovascular repair (EVAR) is the preferred treatment for most aortic aneurysms when anatomy is suitable, offering superior perioperative mortality (<1%) compared to open repair, though it requires lifelong surveillance and carries higher long-term reintervention rates. 1

Abdominal Aortic Aneurysm (AAA)

Indications for Repair

Size thresholds for elective repair:

• ≥55 mm in men or ≥50 mm in women (Class I, Level A recommendation) 1
• ≥45 mm for saccular aneurysms due to increased rupture risk at smaller diameters (Class IIb, Level C) 1
• Rapid growth ≥5 mm in 6 months or ≥10 mm per year may warrant intervention (Class IIb, Level C) 1, 2

EVAR vs Open Repair Decision Algorithm

For ruptured AAA with suitable anatomy:

• EVAR is strongly recommended over open repair to reduce perioperative morbidity and mortality (Class I, Level B) 1
• 30-day mortality: 24.2% for EVAR vs 44.2% for open repair 3
• This survival advantage persists to 5 years (37% vs 26% cumulative survival) 3

For elective AAA in patients with suitable anatomy and life expectancy >2 years:

• EVAR should be considered as the preferred therapy based on shared decision-making (Class IIa, Level B) 1
• Perioperative mortality <1% with EVAR vs approximately 4.2% with open repair 1, 4
• Short-term mortality benefit (1.4% vs 4.2%, OR 0.33) does not persist beyond 4 years 4

For patients with limited life expectancy (<2 years):

• Elective AAA repair is not recommended regardless of technique (Class III, Level B) 1, 2

Complex Anatomy Considerations

For juxta-renal or para-renal AAA:

• Fenestrated or branched stent endografts should be considered to allow perfusion of visceral vessels 1, 2
• Both open and endovascular approaches can be offered in high-volume centers with similar short- and long-term results 1
• Current devices expand treatment possibilities to 60-70% of infrarenal AAA cases 1

Critical Pre-operative Requirements

Mandatory assessments:

• Duplex ultrasound (DUS) of the femoro-popliteal segment to detect concomitant aneurysms (Class IIa, Level B) 1, 2

What NOT to do:

• Routine coronary angiography and systematic revascularization is not recommended in patients with chronic coronary syndromes (Class III, Level C) 1, 2

Descending Thoracic Aortic Aneurysm (DTA)

Treatment Selection

For unruptured DTA aneurysm ≥55 mm:

• TEVAR is recommended over open repair when anatomy is suitable (Class I, Level B) 1
• Intervention threshold may be lowered to <55 mm for women, connective tissue disorders, or rapid growth 1

Important nuance: The early mortality benefit of TEVAR decreases after 1 year, and long-term survival (10 years) appears better with open repair 1. Therefore, open repair is advisable for young, healthy patients with unsuitable TEVAR anatomy and prolonged life expectancy (Class IIa, Level B) 1.

When TEVAR involves planned left subclavian artery (LSA) coverage:

• Revascularize the LSA before TEVAR to reduce risk of spinal cord ischemia and stroke (Class I, Level B) 1

Thoracoabdominal Aortic Aneurysm (TAAA)

Repair Thresholds

Standard threshold:

• ≥60 mm diameter for elective repair in low-moderate surgical risk patients (Class I, Level B) 1

Lower threshold (≥55 mm) should be considered when:

• Patients present with high-risk features 1
• Patients are at very low surgical risk under care of experienced surgeons in multidisciplinary aorta teams (Class IIa, Level B) 1

For suitable anatomy:

• Endovascular repair using fenestrated and/or branched endografts should be considered in experienced centers (Class IIa, Level B) 1
• Post-operative spinal cord ischemia incidence (~5%) is similar between endovascular and open repair 1

Complications and Surveillance

Endoleaks: The Most Common Complication

Incidence and types:

• Endoleaks occur in up to one-third of patients after EVAR 1, 2, 5
• Type I and Type III endoleaks require immediate correction with new endovascular procedures to prevent rupture (Class I, Level B) 1, 2
• Type II endoleaks are present in ~25% of patients but may spontaneously seal and can be observed 1, 2

Risk factors:

• Chronic anticoagulation constitutes a risk factor for reintervention, late conversion surgery, or mortality 1

Mandatory Follow-up Protocol

After EVAR:

• Imaging at 1 month and 12 months post-operatively with CCT (or CMR) and DUS/CEUS (Class I, Level A) 1
• If no abnormalities: DUS/CEUS yearly, repeating CCT or CMR every 5 years (Class I, Level A) 1
• At 6-12 months: assess for growing aneurysm sac (≥10 mm warrants consideration of embolization if feasible) 1

After open AAA repair:

• First follow-up imaging within 1 post-operative year, then every 5 years if findings are stable (Class I, Level A) 1

Reintervention Rates

Critical trade-off:

• EVAR carries significantly higher long-term reintervention rates than open repair (OR 1.98,95% CI 1.12-3.51) 4
• Up to 23% of EVAR patients require secondary interventions for endoleaks or graft migration 3
• Most reinterventions following EVAR are catheter-based with low mortality 4

Common Pitfalls to Avoid

Size threshold errors:

• Do not wait for the standard 55 mm threshold in saccular aneurysms - repair at ≥45 mm due to increased rupture risk 2
• Do not apply male thresholds to women - use ≥50 mm threshold 1

Patient selection errors:

• Do not offer elective repair to patients with life expectancy <2 years regardless of aneurysm size 1, 2
• Do not assume EVAR is always superior - young, healthy patients with long life expectancy may benefit more from open repair due to lower long-term reintervention rates 1, 4

Surgical technique considerations:

• For obese patients undergoing open repair, consider prophylactic mesh use to reduce incisional hernia risk 1, 2

Follow-up failures:

• Failure to maintain lifelong surveillance after EVAR can result in missed endoleaks and rupture 5, 3
• Close follow-up of all EVAR survivors is mandatory given the 23% reintervention rate 3