Aortic Dissection

Question 1

What is aortic dissection? [3]

Answer 1

A tear in tunica intima of aortic wall, blood then enters the tear and forces itself between the layers forming a false 2nd lumen [1] that propagates up or down the aorta.p; chronic forms [1]

Question 2

What causes aortic dissection? [6]

Answer 2

• Direct blunt trauma to chest
• Cardiac Surgery
• Marfan’s Syndrome, EDS
• Congenital Bicuspid AV
• Atherosclerosis
• Familial thoracic aortic aneurysm T1&2

Question 3

What are the risk factors for aortic dissection? [6]

Epidemiology [2]

Answer 3

• Smoking
• Hypercholesterolaemia
• Hypertension
• Pregnancy
• Cocaine use
• Arteritis

Ep: M>F, <50y/o

Question 4

Describe the pain in aortic dissection [5]
Other key symptoms aortic dissection [2]
Symptoms depending on occlusion of smaller arteries by occlusion process [4]

Answer 4

1. Pain
   - Sudden severe back or chest pain
   - Tearing, ripping, sharp character
   - Radiation as dissection progresses
   - Proximal dissection: pain usually restrosternal
   - Distal: pain between scapula and back
2. Cardiac tamponade
3. Pleural effusion (haemothorax): pleuritic pain, SOB
4. Symptoms depending on occlusion of smaller arteries by occlusion process:
   o Coronary arteries: angina or MI
   o Spinal arteries: paraplegia
   o Distal aorta: limb ischaemia, mesenteric ischaemia, renal ischaemia (monitor urine output), retroperitoneal haemorrhage (back pain and bruising)
   o Carotid artery: neuro deficit

Question 5

What are the clinical signs of aortic dissection? [5]

What finding would you see on ECG? [1]

Answer 5

• Reduced or absent peripheral pulses
• BP mismatch between limbs
• AR murmur (sort early diastolic)
• Hyper/Hypotension
• Pulmonary Oedema
• On ECG, Inferior ST elevation

Question 6

How do we investigate a case of Aortic Dissection? [3]

Answer 6

CXR: Can show mediastinal widening - pleural effusion - Loss of aortic knob - tracheal deviation. A -ve CXR doesnt rule out AD

CTA/MRA: MRA is the best and can confirm the diagnosis

TOE: The most common way to confirm the diagnosis

Question 7

Describe the 2 classifications of aortic dissection [5]

Answer 7

Stanford:
A = Asc. Aorta involved - treat Surgically
B = Asc. aorta excluded - Treat medically

Debakey:
1 = Propagates from Asc. Aorta
2 = Stays in Asc. Aorta
3 = Starts in Desc. Aorta and can move

Question 8

How do we medically treat Aortic Dissection? [3]

Which type warrants medical treatment?

Answer 8

Medical treatment is indicated for Stanford B classification
With Strict BP control:
- CCBs 
- Beta Blockers 
- Sodium Nitroprusside (vasodilator)

Question 9

How do we surgically treat Aortic Dissection?

Which type warrants medical treatment?

Answer 9

Surgically replacing the valve and/or a section of the aorta.
Surgical treatment is indicated for Stanford A classification

Question 10

What are the possible complications of aortic dissection? [2]

Answer 10

Rupturing into lumen, pericardium (tamponade) or Mediastinum (haemothorax)

Occlusion of important branches

Question 11

How will a dissected aorta appear histologically? [3]

Answer 11

There will be a loss of elastin & muscle fibres [1] with an accumulation of mucopolysaccharides in cyst-like spaces. [1]

This is called ‘Cystic Medial Necrosis’ [1]