AAA

Question 1

What is an abdominal aortic aneurysm (AAA)?

Answer 1

• This is where there is >50% dilatation of the aortas original diameter.
• Remember it is an ongoing process (continues to increase is size)

Question 2

What are the 2 main types of AAA?

Answer 2

• True aneurysms - involves all 3 layers of the arterial wall
• False aneurysms - involve a collection of blood only in the outer layer

Question 3

Who are AAA most common in ?

Answer 3

Older men

Question 4

What are the causes of AAA?

Answer 4

• Commonest = HTN, DM & smoking
• Others = connective tissue disorders e.g. marfans, trauma, infection

Question 5

What are the signs/symptoms of an unruptured AAA?

Answer 5

• Often asymptomatic
• May cause abdo/back pain or be found on abdominal exammination (expansile mass)

Question 6

What are the signs/symptoms of a ruptured AAA?

Answer 6

• Intermittent or continuous abdo pain (radiates to the back, iliac fossa or groins)
• Collapse & shock)
• Expansile abdo mass (expands & contracts)

Question 7

What screening protocol is done now to try to detect AAA as early as possible ?

Answer 7

All men aged 65 recieve an abdo U/S

Question 8

What is the outcome of the screening abdo U/S ?

Answer 8

• < 3 cm = Normal - No further action
• 3 - 4.4 cm = Small aneurysm - Rescan every 12 months
• 4.5 - 5.4 cm = Medium aneurysm - Rescan every 3 months
• ≥ 5.5cm = Large aneurysm - Refer within 2 weeks to vascular surgery for probable intervention

Question 9

What AAA are considered low risk for rupture and what is done for them?

Answer 9

• Those which are either asymptomatic or aortic diameter < 5.5cm
• Abdominal US surveillance done for these ones

Question 10

What AAA are considered high risk of rupture and what is done for them?

Answer 10

• Those which are either symptomatic, aortic diameter >=5.5cm or rapidly enlarging (>1cm/year)
• refer within 2 weeks to vascular surgery for probable intervention

Question 11

For AAA at high risk of rupture what investigation is then done ?

Answer 11

Arterial phase CT angiography

Question 12

What are the 2 surgical options for treatment of AAA?

Answer 12

2 options:

1. Open surgical repair
2. endovascular aortic aneurysm repair (EVAR)

Question 13

What is the most common way in which an AAA will rupture ?

Answer 13

Retroperitoneal

Question 14

What tends to happen in retroperiotoneal AAA ruptures and why is this relevent to the management of ruptured AAA?

Answer 14

These patients will tend to develop retroperitoneal haematoma. This can be disrupted if Bp is allowed to rise too high so aim for Bp 100mmHg.

Question 15

What should be done to confirm a suspected ruptured AAA?

Answer 15

Bedside abdominal ultrasound

Question 16

What additional investigation should be considerd to be done in someone with a ruptured AAA prior to sugery ?

Answer 16

CT angiography to help plan the surgery

Question 17

What is the preferred treatment of unruptured AAA needing surgery (high risk of rupture)?

Answer 17

Open surgical repair

Question 18

When may EVAR be done for surgical repair of an unruptured AAA requiring surgery (high risk of rupture)?

Answer 18

Only if there are anesthetic or medical contraindications to open surigcal repair

Question 19

What is the perferred surgical treatment of ruptured AAA?

Answer 19

1. Consider EVAR or open surgical repair for people with a ruptured infrarenal abdominal aortic aneurysm (AAA) - EVAR esp in women
2. Consider open surgical repair for people with a ruptured complex AAA - esp younger men

Question 20

What is thoracic aortic dissection ?

Answer 20

This where a tear in the tunica intima of the wall of the aorta forms

Question 21

What are the features of throacic aortic dissection ?

Answer 21

Sudden tearing chest pain which radiates to the back

As dissection expands branches of the aorta occlude leading to:

• Hemiplegia (carotid artery)
• Unequal arm pulses and BP or acute limb ischaemia,
• Paraplegia (spinal arteries)
• Anuria (renal arteries)

Majoirty have no ECG changes

Question 22

How are aortic dissections diagnosed ?

Answer 22

• Do a CXR first but diagnosed confirmed 1st line on CT angiogram
• 2nd line = TOE if CT unsuitable

Question 23

How are thoracic aortic dissections classified ?

Answer 23

• Type A - ascending aorta involved (2/3 of cases)
• Type B - if ascending aorta not involved it is a type B (1/3 of cases)

Question 24

What is the treatment of type A thoracic aortic dissections ?

Answer 24

Type A: ASS
Surgery and Systolic Management - BP should be controlled to a target systolic of 100-120 mmHg whilst awaiting intervention

Question 25

What is the treatment of type B thoracic aortic dissections ?

Answer 25

Type B: BooBs Bed rest and Beta Blockers * Conservative management - bed rest * Reduce blood pressure IV labetalol to prevent progression * May end up needing surgery if distal dissection that is leaking, ruptured or compromising vital organs (recall how it progresses with symptoms)

Question 26

What complications can develop because of a thoracic aortic dissection?

Answer 26

* aortic incompetence/regurgitation * MI: inferior pattern often seen due to right coronary involvement * unequal arm pulses and BP * stroke * renal failure