Abdominal aortic aneurysm
Abdominal aortic aneurysm is focal dilation of the abdominal aorta to 3 cm or more, usually degenerative and often asymptomatic until rupture. Management is risk-factor control and surveillance for small aneurysms and elective repair at 5.5 cm (men) or with rapid growth or symptoms; rupture is a catastrophic emergency.
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What this article covers
- Overview
Definition: abdominal aortic aneurysm (AAA) is a focal dilation of the abdominal aorta to a diameter of 3 cm or more (a loss of parallel walls), usually infrarenal.
- Epidemiology
More common in older men and smokers. Prevalence rises with age.
- Risk factors
Smoking (the strongest modifiable risk factor).
- Pathophysiology
Medial degeneration: inflammation, proteolysis, and loss of elastin and smooth muscle weaken the aortic wall.
- Clinical features
Usually asymptomatic, an incidental or screening finding.
- Differential diagnosis
Thoracic aortic aneurysm: aortic dilation above the diaphragm, distinguished by its location on imaging and a normal-caliber abdominal aorta, unlike the infrarenal dilation of AAA (Thoracic aortic aneurysm).
- Diagnosis
Establish and size with abdominal ultrasound, and use CT angiography for planning and rupture: the diagnostic basis is ultrasound demonstrating an aortic diameter of 3 cm or more (the screening and…
- Management
First-line for small aneurysms, control risk factors and surveil: smoking cessation, blood pressure control (for example amlodipine 5 to 10 mg PO daily), and a statin (atorvastatin 40 to 80 mg PO…
- Complications
Rupture and exsanguination. Distal embolization and limb ischemia.
- Prognosis
Rupture carries very high mortality. Elective repair has low mortality and prevents rupture.
- Prevention
Smoking cessation (the key modifiable measure).
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