Abdominal aortic aneurysm

Question 1

What is the definition of an aneurysm? What is the normal aortic diameter?

Answer 1

Dilatation of a vessel by more than 50% of its normal diameter (can be saccular/fusiform/mycotic)

Normal aortic diameter 1.2 – 2.0 cm

Question 2

What is the difference between a true and a false aneurysm?

Answer 2

True aneurysm:
The vessel wall is intact (i.e. all 3 layers)

False aneurysm:
There is a breach in vessel wall (surrounding structures act as vessel wall)

Question 3

What is the pathogenesis of abdominal aortic aneurysm?

Answer 3

Medial degeneration:
-Regulation of elastin/collagen in aortic wall
-Aneurysmal dilatation
-Increase in aortic wall stress
Progressive dilatation

Question 4

What are the 4 risk factors for AAA?

Answer 4

age: 8% men >65 years
gender- Male:female 6:1
smoking
hypertension

Question 5

What are the two different presentations of AAA?

Answer 5

Asymptomatic (75% of AAA):
-Identified on imaging for other pathology

-Surveillance

Symptomatic:
-Pain - May mimic renal colic

• “Trashing” (distal embolisation causing trash foot: triad of thigh and foot pain, livedo reticularis, and intact peripheral pulses)
• Rupture

Question 6

What are the clinical features of AAA rupture?

Answer 6

Sudden onset epigastric/central pain
May radiate through to back
May mimic renal colic
Collapse

Question 7

What are the 5 clinical features found on examination for AAA?

Answer 7

May look ‘well’

Hypo/hypertensive

Pulsatile, expansile mass +/- tender

Transmitted pulse

Peripheral pulses

Question 8

What are the implications for rupture being retroperitoneal or intra-peritoneal?

Answer 8

Most retroperitoneal, contained rupture

Free intra-peritoneal rupture is rapidly fatal

Question 9

When is an AAA treated?

Answer 9

Symptomatic:
-Pain

• “Trashing”
• Rupture

Asymptomatic:
-Size: >5.5 cm AP diameter
(Surveillance of small AAA)

• Expansion >0.5cm/6 months or >1cm/year
• Surveillance

Question 10

What imaging is used for AAA?

Answer 10

Duplex USS: for asymptomatic/surveillance

• shows AP diameter
• shows involvement iliac arteries

Contrast CT scan in the arterial phase:

• shows shape/size/iliac involvement
• allows for management planning
• ONLY imaging method to identify ruptured AAA

Question 11

What is the different surgical management for AAA?

Answer 11

Open

EVAR: endovascular aneurysm repair