Surgical Management of Infrarenal Abdominal Aortic Aneurysms
Both open surgical repair and endovascular aneurysm repair (EVAR) are indicated treatment options for infrarenal AAAs in good surgical candidates, with the choice depending on patient anatomy, surgical risk, and ability to comply with lifelong surveillance. 1, 2
Treatment Decision Algorithm
Size-Based Intervention Thresholds
Immediate repair is indicated for:
- Infrarenal AAAs ≥5.5 cm diameter to eliminate rupture risk 1, 2
- Any symptomatic AAA regardless of size 1, 2
- Clinical triad of abdominal/back pain, pulsatile mass, and hypotension requires immediate surgical evaluation 1, 2
Repair can be beneficial for:
Intervention is NOT recommended for:
Choosing Between Open vs. Endovascular Repair
Open surgical repair should be the primary choice when: 2
- Patient is a good or average surgical candidate 2
- Patient cannot comply with mandatory lifelong surveillance imaging required after EVAR 1, 2
- Anatomy is unfavorable for endovascular approach 2
Endovascular repair (EVAR) is reasonable when: 2
- Patient is at high risk for open surgery due to severe cardiac, pulmonary, or renal disease 1, 2
- Patient has low or average surgical risk and favorable anatomy (though long-term outcomes still being evaluated) 2
Important caveat: EVAR in high-risk patients has uncertain effectiveness, and the benefit may be limited 1. Technical success rates for EVAR range from 82-89% with deployment success of 98%, but secondary interventions are required in 16% of cases 3.
Perioperative Management
Mandatory perioperative interventions:
- Beta-adrenergic blocking agents must be administered perioperatively (unless contraindicated) to reduce cardiac events and mortality in patients with coronary artery disease 1
- Blood pressure control is essential 2
- Smoking cessation interventions including behavior modification, nicotine replacement, or bupropion 1, 2
Post-Operative Surveillance Requirements
After EVAR (Mandatory Lifelong Surveillance)
The risk of late aortic rupture after EVAR remains >5% through 8 years, making surveillance non-negotiable. 2
Annual surveillance protocol: 2
- Duplex ultrasound annually to monitor for endoleak, sac size changes, stent graft patency, and stent migration/kinking 2
- Cross-sectional imaging (CT or MRI) every 5 years for stable repairs 2
- Immediate additional CT/MRI if ultrasound detects endoleak, sac enlargement, stent migration, kinking, or decreased flow 2
After Open Repair
Long-term surveillance is still necessary: 4
- Biannual CT or MRI scanning of chest and abdomen 4
- 3-8% of patients develop new proximal aortic aneurysms after infrarenal repair, occurring on average 8.2 years later 4
- Evaluate for concomitant aneurysms in other vascular beds 2
Critical Pitfalls to Avoid
Discontinuing EVAR surveillance prematurely is dangerous - lifelong surveillance is mandatory due to persistent late complication risk including rupture 2
Relying solely on ultrasound after EVAR - this may miss stent migration, fracture, or non-contiguous aneurysms; periodic cross-sectional imaging is essential 2
Inadequate resection during open repair - consider resecting the entire infrarenal aorta during initial repair to reduce risk of subsequent proximal aneurysm formation 4
Non-compliance with surveillance - has been associated with 10% rupture rate compared to 0% in compliant patients 2
Comparative Outcomes
Short-term advantages of EVAR include: 3
- Lower 30-day mortality (1.6-2.0% vs. 2-6% for open repair) 3, 5
- Shorter ICU and hospital stays 3
- Lower short-term morbidity 3
However, EVAR requires 16% secondary intervention rate and has uncertain long-term durability compared to open repair 3.