Aortic dissection

Question 1

What is aortic dissection?

Answer 1

Tear in aortic intima allows blood to surge into aortic wall, causing a split between the inner + outer tunica media, creating a false lumen.

Question 2

Describe the predisposing event of aortic dissection

Answer 2

Degenerative changes in the smooth muscle of the aortic media

Question 3

List 8 common causes and predisposing factors of aortic dissection

Answer 3

HTN
Aortic atherosclerosis
Connective tissue disease (e.g. SLE, Marfans, Ehlers–Danlos)
Congenital cardiac abnormalities (e.g. aortic coarctation)
Aortitis (e.g. Takayasus aortitis, tertiary syphilis)
Iatrogenic (e.g. angiography or angioplasty)
Trauma
Crack cocaine.

Question 4

What are the 2 classifications of aortic dissection?

Answer 4

Type A: ascending aorta tear (most common)
Type B: descending aorta tear distal to left subclavian artery

Question 5

Describe the epidemiology of aortic dissection

Answer 5

M > F
Most common in 40-60s

Question 6

What is the cardinal symptom of aortic dissection? What may this mimic?

Answer 6

Sudden central “tearing” pain, may radiate to the back
Mimics MI

Question 7

How may type A and B aortic dissections differ in presentation?

Answer 7

Type A: chest pain predominates
Type B: back pain more typical

Question 8

What are 5 signs of aortic dissection?

Answer 8

Murmur below left scapula descending into abdomen
HTN (if hypotensive may signify tamponade- check for pulses paradoxus)
BP discrepancy between arms of >20mmHg
Signs of AR: Wide pulse pressure, Collapsing pulse, Early Diastolic Murmur
Palpable abdominal mass

Question 9

What bloods should be ordered in aortic dissection?

Answer 9

FBC: anaemia in haemorrhage
X-match 10 units
U+Es (Renal hypoperfusion)
LFTs (Liver hypoperfusion)
Clotting

Question 10

What is seen on CXR in aortic dissection?

Answer 10

Widened mediastinum
Localised bulge in aortic arch

Question 11

Expansion of the false lumen can lead to obstruction of which vessels? What symptoms does this cause?

Answer 11

Subclavian: ataxia, loss of consciousness
Carotid: hemiparesis, dysphasia, blackout
Coeliac: severe abdo pain (due to ischaemic bowel)
Renal arteries: anuria, renal failure
Coronary: angina
Spinal arteries: paraplegia, complete weakness of lower extremeties

Question 12

What is seen on ECG in aortic dissection?

Answer 12

Often NORMAL

If ostia of RCA is compromised you may get signs of LV hypertrophy + Inferior MI

Question 13

What imaging techniques are used in aortic dissection? What is shown in each?

Answer 13

CT Thorax: shows false lumen
Echocardiography: Transoesophageal is highly specific
Cardiac catheterisation + aortography (contrast + XR)