Guidelines for Abdominal Aortic Aneurysm (AAA) Management
Elective repair is recommended when AAA diameter reaches ≥55 mm in men or ≥50 mm in women, with duplex ultrasound (DUS) as the primary surveillance modality. 1
Surveillance Strategy
Use DUS for all AAA surveillance unless inadequate visualization occurs, in which case cardiovascular CT (CCT) or cardiovascular MRI (CMR) is required. 1
Surveillance Intervals Based on Size:
- 25-29 mm diameter: Every 4 years with DUS (if life expectancy >2 years) 1
- 30-39 mm diameter: Every 3 years with DUS 1
- 40-44 mm in women or 40-49 mm in men: Annually with DUS 1
- 45-50 mm in women or 50-55 mm in men: Every 6 months with DUS 1
Women have a four-fold higher rupture risk than men at equivalent diameters, justifying more aggressive surveillance and earlier intervention thresholds. 1
Indications for Intervention
Definitive Indications (Class I):
- ≥55 mm diameter in men 1
- ≥50 mm diameter in women 1
- Symptomatic AAA regardless of size 2
- Ruptured AAA 1
Consider Intervention (Class IIb):
- Rapid growth ≥10 mm per year or ≥5 mm in 6 months (even below size threshold) 1
- Saccular morphology ≥45 mm 1
Do NOT Intervene:
- Limited life expectancy <2 years 1
Choice of Repair Technique
For ruptured AAA with suitable anatomy, endovascular repair (EVAR) is recommended over open repair to reduce perioperative morbidity and mortality. 1
For elective AAA with suitable anatomy and reasonable life expectancy (>2 years), EVAR should be considered as preferred therapy based on shared decision-making, as it reduces perioperative mortality to <1% compared to open repair. 1
Pre-operative Assessment:
- CCT is mandatory for complete aorto-iliac system evaluation and EVAR feasibility determination 1, 3
- DUS assessment of femoro-popliteal segment should be performed to detect concomitant aneurysms 1
- Routine coronary angiography and systematic revascularization is NOT recommended in patients with chronic coronary syndromes 1
Common Pitfall:
Do not perform routine pre-operative coronary revascularization, as evidence shows this strategy does not improve outcomes or reduce 30-day MI rates. 1
Medical Management
Optimal cardiovascular risk management and medical treatment are recommended for all AAA patients to reduce major adverse cardiovascular events (MACE). 1
Specific Recommendations:
- Intensive lipid management with LDL-C target <1.4 mmol/L (<55 mg/dL) if embolic event with aortic arch atheroma 1
- Single antiplatelet therapy (SAPT) should be considered in complicated aortic atherosclerotic plaques with concomitant CAD 1
- Avoid fluoroquinolones unless compelling clinical indication with no reasonable alternative 1
Important Caveat:
Low-dose aspirin is not associated with higher AAA rupture risk but could worsen prognosis in cases of rupture. 1
Post-Intervention Surveillance
Perform 30-day imaging with CCT plus DUS/contrast-enhanced ultrasound (CEUS) to assess intervention success. 1, 3
Long-term Follow-up:
- Follow-up at 1 and 12 months post-operatively, then yearly until fifth post-operative year 3
- Type I and Type III endoleaks require correction with new endovascular procedure 1
- Type II endoleaks are present in ~25% of patients but may seal spontaneously; intervene only if associated with aneurysm sac expansion 1, 4
Surveillance After EVAR:
Lifelong surveillance is mandatory due to higher risk of late complications (endoleaks, migration, rupture) and re-interventions compared to open repair. 1
Initial Evaluation
When an AAA is identified at any location, assessment of the entire aorta is recommended at baseline and during follow-up. 1