Management of Infrarenal Abdominal Aortic Aneurysm
For good surgical candidates with infrarenal AAA ≥5.5 cm, both open and endovascular repair are equally indicated, with no long-term survival difference between techniques. 1
Size-Based Treatment Algorithm
Aneurysms ≥5.5 cm
- Repair is indicated to eliminate rupture risk, regardless of whether open or endovascular approach is chosen. 1, 2
- Both techniques demonstrate equivalent all-cause mortality (7.5 vs 7.7 deaths per 100 person-years) and aneurysm-related mortality (1.0 vs 1.2 deaths per 100 person-years) over 6-year follow-up, based on the EVAR trial of 1,252 patients. 1
- Endovascular repair offers lower 30-day mortality (1.8% vs 4.3%, P=0.02) but requires reintervention in 5.1% of patients compared to 1.7% for open repair (P<0.001). 1, 2
Aneurysms 5.0-5.4 cm
- Repair can be beneficial and should be strongly considered, particularly in women where intervention is recommended at ≥5.0 cm. 2, 3
- Surveillance every 6-12 months with ultrasound or CT is appropriate if repair is deferred. 3
Aneurysms 4.0-4.9 cm
- Monitoring every 6-12 months by ultrasound or CT is indicated. 3
- Intervention is not recommended for asymptomatic aneurysms <5.0 cm in men or <4.5 cm in women. 3
Aneurysms <4.0 cm
- Surveillance every 2-3 years with ultrasound is reasonable. 3
Immediate Repair Indications (Regardless of Size)
Symptomatic Aneurysms
- Any patient with abdominal/back pain, pulsatile mass, and hypotension requires immediate surgical evaluation and repair within 24-48 hours. 2, 3, 4
Rapid Expansion
- Growth ≥0.5 cm in 6 months or ≥1.0 cm/year warrants repair within 2-4 weeks to allow cardiac risk stratification. 2, 4
Choosing Between Open vs. Endovascular Repair
Favor Endovascular Repair When:
- Patient is good surgical candidate with suitable anatomy on CT angiography. 1, 2
- Lower 30-day procedural mortality is prioritized (1.8% vs 4.3%). 1, 2
- Patient can comply with mandatory lifelong surveillance imaging. 1, 2
Favor Open Repair When:
- Patient cannot comply with lifelong post-EVAR surveillance requirements. 1, 2
- Hostile neck anatomy makes EVAR technically unsuitable. 4
- Patient preference after informed discussion of equivalent long-term outcomes. 1
Uncertain Effectiveness:
- Endovascular repair in patients at high surgical/anesthetic risk due to severe cardiac, pulmonary, or renal disease has uncertain effectiveness. 1, 3
Pre-Intervention Workup
Imaging Requirements
- Obtain CT angiography with 3D reconstruction to assess EVAR anatomic suitability, neck anatomy, iliac access, and plan repair approach. 2, 4
- Measure external anteroposterior diameter, not residual lumen, as mural thrombus does not change size-based repair thresholds. 2
Cardiac Risk Optimization
- Start beta-blocker therapy if not contraindicated, particularly for patients with coronary disease. 2, 4
- Aggressive blood pressure control reduces wall stress. 2, 4
Medical Management During Surveillance
Mandatory Interventions
- Smoking cessation is mandatory using behavior modification, nicotine replacement, or bupropion. 2, 3
- Aggressive blood pressure control to reduce wall stress. 2, 3
Pharmacologic Considerations
- Beta-blockers may be considered to reduce expansion rate, though propranolol trials showed serious side effects. 2, 3, 5
- Statins have shown potential in observational studies to limit AAA expansion. 5
- Perioperative beta-blockade is indicated for patients with coronary disease undergoing repair. 2
Post-EVAR Surveillance Protocol
Imaging Schedule
- Lifelong surveillance imaging is mandatory to monitor for endoleaks, sac stability, stent migration, and graft position. 1, 2, 4
- CT imaging at 1 month, 12 months, then annually if stable. 4
- Annual duplex ultrasound to monitor for endoleaks, sac size changes, stent patency, and migration. 3
- Cross-sectional imaging (CT or MRI) every 5 years to assess stent integrity and subtle endoleaks. 3
Critical Pitfall
- Non-compliance with surveillance is associated with 10% rupture rate versus 0% in compliant patients. 4
- Immediate additional CT or MRI is required if ultrasound detects endoleak, sac enlargement, stent migration, kinking, or decreased flow. 3