Aortic dissection

Question 1

Define aortic dissection

Answer 1

Condition where a tear in the aortic intima allows blood to surge into aortic wall, causing a split between inner & outer tunica media, creating a false lumen

TYPE A - ascending aorta (most common)
TYPE B - descending aorta (distal to left subclavian artery)

Question 2

Aetiology of aortic dissection

2

Answer 2

Usually preceded by degenerative changes in the smooth muscle of the aortic media

Expansion of the false lumen can lead to obstruction of the subclavian, carotid, coeliac & renal arteries
hypoperfusion of target organs can lead to other symptoms

Question 3

Epidemiology of aortic dissection

age/gender

Answer 3

Most common in males 40-60 years old

Question 4

Presenting symptoms of aortic dissection

main + 6

Answer 4

MAIN SYMPTOM
Sudden central “tearing” pain that may radiate to back in between shoulder blades (can mimic MI)

Other symptoms caused by obstruction of branches of aorta:

Carotid artery - hemiparesis, dysphasia, blackout
Coronary artery - chest pain (angina or MI)
Subclavian artery - ataxia, loss of consciousness
Anterior spinal artery - paraplegia
Coeliac axis - severe abdominal pain (due to ischaemic bowel)
Renal artery - anuria, renal failure

Question 5

Signs of aortic dissection on physical examination

8

Answer 5

Murmur on back (below left scapula) descending to abdomen

Hypertension

BP diff. between 2 arms >20mm Hg

Wide pulse pressure

Hypotension may suggest tamponade
- check pulsus paradoxus

Signs of aortic regurgitation

Unequal arm pulses

May be palpable abdominal mass

Question 6

Risk factors for aortic dissection

8

Answer 6

HYPERTENSION
Aortic atherosclerosis
Connective tissue disease (e.g. Marfan’s, Ehlers-Danlos, SLE)
Congenital cardiac abnormalities (e.g. coarctation of aorta)
Aortitis
Iatrogenic (e.g. during angioplasty/angiography)
Trauma
Crack cocaine

Question 7

Signs of aortic regurgitation

2

Answer 7

High volume collapsing pulse

Early diastolic murmur over aortic area

Question 8

Investigations for aortic dissection

6

Answer 8

Bloods
CXR
ECG
CT thorax
Echocardiography
Cardiac catheterisation & aortography

Question 9

Investigations for aortic dissection - bloods

4

Answer 9

FBC
X-match 10 units of blood
U&Es - check renal function
Clotting screen

Question 10

Investigations for aortic dissection - CXR

Answer 10

Widened mediastinum

Question 11

Investigations for aortic dissection - ECG

2

Answer 11

Often NORMAL

If ostia of right coronary artery is compromised, may get signs of left ventricular hypertrophy or inferior MI

Question 12

Investigations for aortic dissection - CT thorax

Answer 12

Shows false lumen

Question 13

Investigations for aortic dissection - echocardiography

Answer 13

Transoesophageal allows visualisation