Abdominal Aortic Aneurysm Rupture

Question 1

What are the risk factors for abdominal aortic aneurysm rupture?

Answer 1

The risk of AAA rupture increases exponentially with the diameter of the aneurysm, but the risk is also increased by smoking, hypertension, and female gender.

Question 2

What are the clinical features of AAA rupture?

Note: signs and symptoms

Answer 2

An AAA rupture can present with abdominal pain, back pain, syncope or vomiting.

Question 3

What are the clinical features of AAA rupture?

Note: on examination

Answer 3

On examination they will typically be haemodynamically compromised, with a pulsatile abdominal mass and tenderness.

Question 4

What is the ‘classic triad’ of ruptured AAA?

Answer 4

Around 50% patients present with the ‘classic triad’ of ruptured AAA:

1. Flank or back pain
2. Hypotension
3. Pulsatile abdominal mass

Question 5

In which direction do most AAA rupture? And how does this impact prognosis?

Answer 5

20% of AAA ruptures will rupture anteriorly into the peritoneal cavity, which are associated with a very poor prognosis.

80% rupture posteriorly into the retroperitoneal space.

Question 6

Briefly describe what is shown on the CT scan

Answer 6

A ruptured AAA, as seen on axonal imaging on CT scan, rupturing into the retroperitoneal space.

Question 7

Briefly describe the management of AAA rupture

Answer 7

Any suspected AAA rupture warrants immediate high flow O₂, IV access (2x large bore cannulae), and urgent bloods taken (FBC, U&Es, clotting) with crossmatch for minimum 6U units.

Any shock should be treated very carefully.

The patient should be transferred to the local vascular unit, with the vascular registrar, consultant, anaesthetist, theatre and blood transfusion lab informed.

• If the patient is unstable, they will require immediate transfer to theatre for open surgical repair
• If the patient is stable, they will require a CT angiogram to determine whether the aneurysm is suitable for endovascular repair

Question 8

Why does shock need to be treated carefully in AAA rupture?

Answer 8

Raising the BP will dislodge any clot and may precipitate further bleeding, therefore aim to keep the BP≤100mmHg (termed ‘permissive hypotension’, preventing excessive blood loss). As long as the patient is cerebrating, the BP is generally adequate.