Aortic Dissection

Question 1

Define Aortic Dissection

Answer 1

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

Question 2

Classification of aortic dissection

Answer 2

Type A: ASCENDING aorta (MOST COMMON)

Type B: DESCENDING aorta (distal to the left subclavian artery)

Question 3

Explain the aetiology

Answer 3

Aortic dissection is usually preceded by degenerative changes in the smooth muscle of the aortic media

Question 4

Common causes and risk factors

Answer 4

HYPERTENSION

Aortic atherosclerosis

Connective tissue disease (e.g. Marfan’s, Ehlers-Danlos- stretchy, fragile skin, hypermobility, SLE)

Congenital cardiac abnormalities (e.g. coarctation of the aorta)

Aortitis

Iatrogenic- due to medication/ examination (e.g. during angioplasty/angiography)

Trauma

Crack cocaine

NOTE: expansion of the false lumen can lead to obstruction of the subclavian, carotid, coeliac and renal arteries

Hypoperfusion of the target organs of these major arteries can give rise to other symptoms (e.g. carotid artery –> collapse)

Question 5

Summarise the epidemiology of aortic dissection

Answer 5

Most common in males aged 40-60 yrs

Question 6

Recognise the presenting symptoms of aortic dissection

Answer 6

MAIN SYMPTOM: sudden central ‘tearing’ pain, it may radiate to the back in between the shoulder blades (it can mimic MI)

Question 7

Other symptoms caused by obstruction of branches of the aorta

Answer 7

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 8

Recognise the signs of aortic dissection on physical examination

Answer 8

Murmur on the back (below the left scapula), descending to the abdomen

Hypertension

Blood pressure difference between the two arms > 20 mm Hg

Wide pulse pressure

Hypotension may suggest tamponade

Question 9

Cardiac tamponade

Answer 9

When fluid in the pericardium (the sac around the heart) builds up, resulting in compression of the heart

Question 10

pulsus paradoxus

Answer 10

abnormally large decrease in systolic blood pressure and pulse wave amplitude during inspiration

Question 11

what does pulsus paradoxus indicate

Answer 11

Tamponade

Pericarditis

Chronic sleep apnoea

Obstructive lung disease

Question 12

Signs of Aortic Regurgitation

Answer 12

High volume collapsing pulse

Early diastolic murmur over aortic area

Unequal arm pulses

There may be a palpable abdominal mass

Question 13

Identify appropriate investigations for aortic dissection

Answer 13

Bloods 
CXR 
ECG 
CT Thorax 
Echocardiography 
Cardiac catheterisation and aortography