Aortic Aneurysm

Question 1

Where do abdominal aortic aneurysms occur?

Answer 1

Usually located below the level of the renal arteries (infra-renal)

Question 2

What are the risk factors for abdominal aortic aneurysm?

Answer 2

• Atherosclerosis and its risk factors- smoking, hypertension, cholesterol.
• Demographic- male, older
• Family history
• Rarely, due to specific inflammatory (Behcet’s) or connective tissue (Marfan’s) cause.

Question 3

How does stable abdominal aortic aneurysm present?

Answer 3

Stable aneurysm-

• Usually asymptomatic - can be detected through screening.
• On examination- there may be a pulsatile mass visible or palpable in the abdomen. Pain on palpation suggests increased risk of rupture.

Question 4

How does a ruptured abdominal aortic aneurysm present?

Answer 4

• Abdominal, flank or back pain.
• Shock
• Syncope- consider ruptured AAA in all older men(>55) or women (>70) presenting with collapse.

Question 5

How is suspected abdominal aortic aneurysm investigated?

Answer 5

Bloods-

• Basic bloods- FBC, coag, U&E, LFTs
• Pre-op- cross-match

Imaging-

• CXR
• ECG
• Diagnosis is usually with US. One off screening is offered to men in the UK age 65.
• CT contrast or MRI angio provide more information and are used if US not clear or before planned surgery. CT may show ‘high-attenuating crescent’, a bleed within the aneurysmal wall suggesting imminent rupture.

Question 6

How is stable abdominal aortic aneurysm managed?

Answer 6

Conservative-
Regular US monitoring if small and asymptomatic
Manage risk factors
Contact DVLA if >6cm

Surgical-
Indications- aneurysm >5.5cm.
At this point, the risk of rupture overtakes the risk of surgery for most. This may differ in those who are not fit for surgery.
Open repair involves clamping the artery and sewing a graft inside the aneurysm sac to replace it.
Endovascular aneurysm/aortic repair is a less invasive alternative, whereby stents are inserted through the femoral artery. Quicker recovery, lower short-term mortality and no long-term mortality difference. Risk of endovascular leaks, which need to be monitored with regular CT or US.
1.5% in-hospital mortality risk after elective repair.

Question 7

How is ruptured abdominal aortic aneurysm managed?

Answer 7

• Resuscitation with blood products.
• Emergency repair- open repair traditionally used, but EVAR increasingly used.
• 80% mortality risk, 40% if operated.

Question 8

What is a pseudoaneurysm?

Answer 8

A bleed from an artery which pools in an enclosed compartment next to the vessel. Vessel not dilated.

Question 9

What is an aneurysm?

Answer 9

Dilation of an artery which is bound by all 3 walls of the vessel (intimate, media, adventitia). Is at risk of rupture or dissection.