Aneurysms

Question 1

What is an aneurysm?

Answer 1

An artery with a dilation >1.5x its original diameter.

Question 2

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

Answer 2

1. True - abnormal dilations involving all layers of arterial wall.
2. False - collection of blood in outer layer only (communicates with lumen)

Question 3

Where do >90% of AAAs occur?

Answer 3

Below the renal arteries

Question 4

What is the underlying aetiology of an aneurysm?

Answer 4

1. Media layer (smooth muscle) gives aorta strength.
2. Enlarging atherosclerotic plaque causes degradation of aortic wall connective tissue, inflammation, infiltration of lymphocytes and decreased elastin.
3. Aortic wall weakened and it dilates.
4. Atheroma, trauma, connective tissue disorders, inflammation.

Question 5

Where are the most common sites for aneurysm formation?

Answer 5

1. Aorta (infrarenal)
2. Iliac arteries
3. Femoral arteries
4. Popliteal arteries

Question 6

In which patient groups is an unruptured AAA more common?

Answer 6

> 50 years old, M:F 6:1, less common in diabetics.

Question 7

What symptoms may be present in an unruptured AAA?

Answer 7

1. Often none
2. May be abdominal/back pain
3. Often discovered incidentally on abdominal exam

Question 8

What are the risk factors for the development of an unruptured AAA?

Answer 8

1. Atherosclerosis - cigarette smoking
2. FHx of AAA
3. Increased age - >55yrs in men, >65yrs in women
4. HTN, high cholesterol
5. Caucasian
6. Connective tissue disorders

Question 9

How do you investigate a suspected unruptured AAA?

Answer 9

1. Presence of RFs
2. Abdominal mass only tends to be felt when >5cm
3. USS definitive test

Question 10

What is the management for symptomatic unruptured AAA?

Answer 10

Repair indicated regardless of diameter.

Question 11

What is the management for an asymptomatic unruptured AAA?

Answer 11

1. Annual USS screening 3-4.5cm, quarterly 4.5-5.5cm
2. Elective surgery >5.5cm/expanding >1cm per year/becomes symptomatic.
3. Control RFs - smoking cessation, statins and antihypertensives.

Question 12

Which patients are more likely to have a rupture of a AAA?

Answer 12

Female, HTN, smoker, +ve FHx

Question 13

Which groups are invited for AAA screening in the UK?

Answer 13

All males >65 years of age

Question 14

What is the surgical option in an unruptured AAA?

Answer 14

EVAR (endovascular aneurysm repair) - symptomatic AAA, less early mortality but higher graft complications.

Question 15

What are the complications of a AAA?

Answer 15

1. Rupture

2. Thrombosis and embolism

Question 16

What is this a presentation of?
Intermittent or continuous abdominal pain (radiating to back, iliac fossa, or groins). Collapse, shock, expansile abdominal mass.

Answer 16

Ruptured AAA

Question 17

What is the classic triad in ruptured AAA?

Answer 17

Abdominal pain, expansile abdominal mass, and hypotension.

Question 18

What is the emergency management of a ruptured AAA?

Answer 18

1. Call vascular surgeon and anaesthetist and warn theatre.
2. ECG, bloods (amylase, Hb, crossmatch), catheterise.
3. IV access with 2 large bore cannulas.
4. Treat shock with O Rh- blood.
5. Keep systolic BP <100mmHg to avoid rupturing contained leak.
6. CT needed
7. Prophylactic Abx (co-amoxiclav 625mg IV)
8. Open surgery (clamping aorta, end organ ischaemia, reperfusion injury) vs EVAR

Question 19

What is the difference between a fusiform and a saccular aneurysm?

Answer 19

1. Fusiform - 360 degrees of vessel wall

2. Saccular - one area of vessel wall