Aortic Dissection

Question 1

Definition

Answer 1

Tear in vascular tunica intima resulting in blood dissecting through tunica media creating a false lumen. Results in abnormal flow through false lumen occluding flow through branches of the aorta.
Surgical emergancy
Separating layers apart

Question 2

Risk factors

Answer 2

• HTN
• Smoking
• Family history
• Bicuspid aortic valve
• Coarctation of the aorta
• Connective tissue disorders: Marfans, Ehlers Danlos
• Turners and Noonans
• Trauma
• Pregnancy
• Syphillis

Question 3

Pathology

Answer 3

Tear in intimal layer of aorta = collection of blood between intima + medial layers.
Blood dissects media + intima + pools in false lumen which can propagate fowards (anterograde - toward aortic root) or backwards (retrograde) -> decreased perfusion to end organs; organ failure + shock

Question 4

Signs and symptoms

Answer 4

Symptoms:
- SUDDEN ONET RIPPING/TEARING CHEST PAIN
- Syncope
Signs:
- Radio-radial or radio-femoral delay
- A difference in blood pressure between two arms: >10 mmHg
- Tachycardia and hypotension
- Diastolic murmur
- Signs of connective tissue disorders

Question 5

Diagnosis

Answer 5

ECG: non specific changes: T wave inversion, ST segment depression or elevation
CXR - widened mediastinum -> 8cm SUSPICIOUS
Group & Save crossmatch: all suspected patients in event of transfusion
U&Es: Required prior to CT with contrast for pre-renal AKI
GOLD STANDARD = Contrast-enhanced CT angiogram: intimal flap, false lumen, rupture/leak
Transoesophageal echocardiography (TOE) more suitable for unstable patients who are too risky to take to CT scanner

Question 6

Stanford classification

Answer 6

STANFORD CLASSIFICATION
A: Proximal to left subclavian artery, dissection involves ascending aorta with or without involvement of arch
B: Distal to left subclavian artery, at the descending thoracic aorta or abdominal aorta

Question 7

De Bakey Classification

Answer 7

Type I : originates in the ascending aorta and involves at least the aortic arch, but can extend distally
Type II : originates and confined to the ascending aorta
Type III : originates in the descending aorta and extends distally, but can extend proximally

Question 8

Treatment

Answer 8

Surgical = open repair (typically A) or endovascular repair (more B)
If hypotensive = consider IV fluid, blood transfusion + adrenaline
Medical (prevention) = AIM (SBP 100-120, HR - 60s)
FIRST LINE = SPECIAL BB = ESMOLOL or LABETOLOL
* beta-blocker + partial a/b; prevents reflex tachycardia = decrease BP
SECOND LINE = vasodilator = SODIUM NITROPRUSSIDE

Question 9

Complication

Answer 9

Cardiac tamponade
Aortic insufficiency (regurg)
Pre-renal AKI
Stroke (Ischaemic)