Abdominal Aortic Aneurysm - Condition Summary

ABDOMINAL AORTIC ANEURYSM (AAA)
AAA = abnormal dilatation of abdominal aorta with a diameter > 3cm.
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Presentation
Frequently asymptomatic, the presence of symptoms often indicates rupture/impending rupture.
§ Back pain or loin pain
§ Abdominal pain ® radiates to back
§ Haemodynamic compromise ® hypotension, tachycardia, collapse
§ Pulsatile abdominal mass.
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Pathophysiology
§ Considered a degenerative condition of the aorta, but it’s aetiology not fully understood
§ Less common causes: secondary to infection, inflammatory disease or trauma

Risk factors ® age, male, atherosclerotic disease, FH, smoking, hypertension, connective tissue disorder.
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Investigation
Screening
§ On NHS for men aged 65 and over
§ Also indicated if patient at greater risk of AA (e.g. FH)
o NICE guidance 2020: consider in women >70 with any one of COPD/vascular
disease/FH/hyperlipidaemia/hypertension/smoker or ex-smoker
§ Consists of abdominal USS
§ <3cm: no follow up required
§ 3-4.4cm: advise yearly screening with USS, lifestyle advise, refer to vascular service to be seen within 12 weeks
§ 4.5-5.4cm: advise 3 monthly screening with USS, lifestyle advise, refer to vascular service to be seen within 12 weeks
§ >5.4cm: urgent 2ww referral to vascular for management.

Bloods
§ FBC, U&E, LFT, clotting, ABG/VBG, G&S, crossmatch.

AXR
§ Not sensitive test
§ May be routinely ordered in work up of abdominal pain
§ May show: dilated aorta if aortic wall calcification seen

Abdominal USS
§ Simple, non-invasive
§ Readily available and commonly done.

MRI/CT
§ Used for pre-op in elective setting to plan
§ May be used acutely in stable patients.

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Management
Elective Management
Conservative
§ Stable AAA not requiring surgical input
§ Advised to follow healthy lifestyle, evaluated for hyperlipidaemia and HTN and treated
§ AAA monitored based on diameter.

Surgical
§ Open surgical repair
§ Elective surgery indicated in:
o Diameter >5.5 cm
o Symptomatic aneurysms
o Asymptomatic >4 cm and grown by >1 cm in 1 year