What is an Endovascular Aneurysm Repair (EVAR)?

What is Endovascular Aneurysm Repair (EVAR)?

EVAR is a minimally invasive procedure that treats abdominal aortic aneurysms by placing a stent-graft inside the aneurysm to exclude it from arterial circulation, thereby preventing rupture. 1, 2

Procedure Overview

EVAR involves deploying a bifurcated or tubular stent-graft through small groin incisions (rather than open laparotomy) to line the inside of the aneurysm and redirect blood flow away from the weakened aortic wall. 2, 3 The stent-graft is typically inserted via the femoral arteries and positioned to create proximal and distal "landing zones" that seal against healthy aortic tissue. 1

Key Anatomic Requirements

For conventional EVAR to be feasible, specific anatomic criteria must be met:

• Proximal neck length: ≥10-15 mm of healthy aorta below the renal arteries 1
• Proximal neck diameter: <30 mm 1
• Neck angulation and morphology: Favorable configuration without excessive calcification (>90% circumferential calcification increases risk of type I endoleak and graft migration) 1
• Iliac access: Adequate diameter and tortuosity to accommodate device delivery 1

More than 50% of patients have anatomy unsuitable for conventional EVAR, though fenestrated EVAR (FEVAR) extends treatment options for those with inadequate neck length. 1

Clinical Advantages Over Open Repair

EVAR demonstrates significant perioperative benefits:

• Reduced 30-day mortality: 1.7% with EVAR versus 4.7% with open repair (odds ratio 0.35, p=0.009) 1, 4
• Decreased hospital stay and perioperative morbidity 1
• Minimal surgical trauma: Only requires stab incisions rather than laparotomy 2, 5
• Faster recovery time 2, 3

However, long-term mortality equivalence emerges over time, with similar all-cause mortality rates at 6 years (7.5 vs 7.7 deaths per 100 person-years, p=0.72). 1

Critical Limitation: Lifelong Surveillance Requirement

The primary trade-off of EVAR is mandatory lifelong imaging surveillance due to higher reintervention rates compared to open repair (5.1% vs 1.7%, p=0.001). 1 This surveillance requirement makes EVAR less suitable for patients unable to comply with regular follow-up. 1, 3

Surveillance Must Monitor For:

• Endoleaks (most common complication—blood flow outside graft but inside aneurysm sac) 1
• Aneurysm sac expansion (indicating treatment failure and rupture risk) 1
• Stent-graft complications: Migration, kinking, thrombosis, infection 1
• Renal dysfunction 1

Endoleak Classification and Management

Endoleaks occur in up to one-third of EVAR cases and are classified by etiology: 1

• Type I and Type III: Require immediate correction as they expose the sac to systemic pressure 1
• Type II: Present in ~25% of patients but may spontaneously seal 1

Current Guideline Recommendations

For patients with suitable anatomy and reasonable life expectancy (>2 years), EVAR should be considered as the preferred therapy based on shared decision-making. 1 The 2024 ESC guidelines specifically recommend EVAR over open repair for ruptured AAA with suitable anatomy to reduce perioperative morbidity and mortality. 1

Open repair remains reasonable for good surgical candidates who cannot comply with lifelong surveillance requirements. 1

Common Pitfall to Avoid

Do not offer EVAR to patients with limited life expectancy (<2 years) or those unlikely to maintain long-term imaging follow-up, as the reintervention burden negates perioperative advantages. 1 The requirement for lifelong CTA surveillance (with associated radiation exposure and contrast nephrotoxicity risk) must be explicitly discussed during shared decision-making. 1