Aortic Dissection

Question 1

Definition of aortic dissection

Answer 1

Tear in intima resulting in a false lumen between aortic layers, with blood dissecting through media & separating layers - surgical emergency/shock

Question 2

AD are due to?

Answer 2

Mechanical wall stress, weakened aortic wall

Question 3

Risk factors for AD?
What’s the main cause?

Answer 3

Hypertension (MC) due to stress = increased blood vol or coarctation (narrowing)

Connective tissue disorders (marfins syndrome, Ehlers Danlos syndrome)

Family history

AAA/AD

Trauma

Smoking

Aneurysms

Question 4

Anatomy of aorta from LV to descending aorta?

Answer 4

Insert pic

Question 5

What are the 2 main locations for AD?

Answer 5

1. Sinotubular junction - where aortic root becomes ‘tubular’ aorta, near aortic valve - most common (A)

2 just distal to left subclavian artery (in descending aorta - thoracic) (B)

Question 6

what are the 2 classifications for location of AD?

Answer 6

Stanford
Debakey

Question 7

What is the Stanford classification for location of AD?

Answer 7

A - proximal to left subclavian artery (ascending + arch) 2/3 MC

B - distal to left subclavian (descending thoracic) 1/3 LC

Question 8

What is the debakey classification for location of AD?

Answer 8

1. Aortic root (sinotubular junction - MC)
2. Aortic arch
3. Descending aorta

Question 9

Pathology of AD

Answer 9

Blood dissects intima + media + pools in false lumen which can propagate forwards (anterograde) -along aorta or backwards (retrograde- towards aortic root)

Low perfusion to end organ = organ failure + shock

Question 10

Signs and symptoms of AD

Answer 10

Sudden onset, ripping/tearing chest pain, radiate to back

systemic shock/hypotension

Radio-radial delay (BP)
10+ mmHg
(brachial/femoral - left arm)
Difference in BP in L&R arms

Weak peripheral pulse

New aortic insufficiency murmur (aortic regurgitation)
Retrograde blood pooling if at sinotubular junction

Question 11

Differential diagnosis for AD?

Answer 11

MI
Central crushing with gradually worsening intensity

Question 12

Diagnosis of AD

Answer 12

Chest x ray = widened mediastinum/aorta
>8cm = suspicious

Gold standard =
CT angiogram (v specific + sensitive) - intimal flap, false lumen, rupture/leak
Used more if patient haemodynamically stable

(Can do TOE (transoesophageal echocardiogram)
More invasive than TTE but more specific & sensitive for AD
Classify AD as A or B)

Question 13

2 Surgical treatment for AD

Answer 13

open repair (remove dissected aorta & reconstruct it)

EVAR (stent inserted)

Question 14

Tx for AD?
medical and surgical
A and B

Answer 14

A = Requires surgery and give IV Labetalol

B = No surgery, just give IV Labetalol

Question 15

What type of medication is given in AD and why?
what medication don’t we give and why?

Answer 15

Labetalol
Combine alpha and beta blocker
-ve chronotropy and ionotropy (beta)
Peripheral vasodilation to lower BP (alpha)

Doesn’t cause reflex tachycardia (eg. like nitroprusside)

Question 16

Complications of AD

Answer 16

Total transmural aorta rupture = death

Cardiac tamponade

Organ ischemia (renal - pre renal AKI/ Cerebral - stroke/ bowel/ limbs/necrosis)

Question 17

Causes of radio radial delay?
(3 conditions)

Answer 17

Aortic dissection
Co arctation of aorta
Subclavian artery stenosis