Abdominal Aortic Aneurysm (AAA)

smart doctor on

 

Abdominal Aortic Aneurysm (AAA)

Definition

  • True aneurysm = dilation of all 3 layers of aortic wall (intima, media, adventitia)

  • AAA: diameter ≥ 3 cm or ≥1.5 × normal

  • Location:

    • Infrarenal (most common, often extends to iliacs)

    • Suprarenal (less common)

  • Shape: fusiform (most) or saccular

Epidemiology

  • Peak: 60–70 yrs

  • M > F (≈ 2:1)

  • More common than TAA

Risk factors

  • Smoking (most important)

  • Advanced age

  • Atherosclerosis, hyperlipidemia, HTN

  • Male sex

  • Family history

  • Trauma

Pathophysiology

  • Inflammation + proteolytic degradation of collagen/elastin

  • Wall weakening → dilatation

  • Turbulence + mural thrombus → embolization (blue toe syndrome)

Clinical features

  • Usually asymptomatic (often incidental)

  • Symptomatic (before rupture):

    • Back/abdominal pain

    • Pulsatile abdominal mass (at/above umbilicus)

    • Bruit

    • Distal embolization (blue toe, livedo reticularis)

Diagnosis

  • Best initial & confirmatory: abdominal ultrasound (screening + surveillance)

  • CT angiography: best for symptomatic patients & preoperative planning

  • MRA: alternative if CT contraindicated

  • Arteriography: lumen only (may underestimate size due to thrombus)

Surveillance

  • Men 65–75 y, ever smokers → one-time US screening

  • Follow-up by size:

    • 3–3.9 cm → US q3y

    • 4–4.9 cm (men) / 4–4.4 cm (women) → US yearly

    • ≥5.0 cm (men) / ≥4.5 cm (women) → US q6mo

Management

General

  • Control CV risk: stop smoking, manage HTN, DM, lipids

  • Regular surveillance if below surgical threshold

Surgery (vascular consult)

Indications:

  • Symptomatic aneurysm

  • Rupture or impending rupture (emergency repair)

  • Asymptomatic but:

    • ≥5.5 cm (men), ≥5.0 cm (women)

    • Growth ≥0.5 cm/6mo

Procedures:

  • EVAR (endovascular repair): less invasive, preferred in high-risk pts; higher re-intervention rates

  • OSR (open surgical repair): durable, indicated for mycotic aneurysm, infected graft, unsuitable anatomy for EVAR

Ruptured AAA

  • Risk: large size, rapid growth, smoking

  • Classic triad:

    1. Severe tearing abdominal/back pain

    2. Pulsatile abdominal mass

    3. Hypotension/shock

  • May see Cullen/Grey-Turner signs (retroperitoneal bleed)

  • Management:

    • Permissive hypotension (SBP 70–90 mmHg)

    • Large-bore IVs, cross-match blood, massive transfusion protocol

    • Immediate vascular surgery (EVAR or OSR)

  • Mortality ≈ 80%

Complications

  • Rupture

  • Embolism → blue toe syndrome

  • Dissection

  • Post-repair: endoleak, graft infection, aortoenteric fistula, ischemia (bowel, kidneys, spinal cord)

Comments

Post a Comment