Aortic dissection

Question 1

What is an aortic dissection?

Answer 1

An aortic dissection is a tear in the tunica intima, causing blood to pool between the tunica intima and media, creating a false lumen, that may or may not communicate back to the true lumen. There are two types, one that affects the ascending aorta (Type A), and one that affects below the ascending aorta (Type B).
The dissection can bypass branches of the aorta causing no blood supply to these arteries (Coronary Arteries cause angina, spinal arteries cause paraplegia, distal aorta causes acute limb ischaemia, carotid arteries causes neurological deficit)

Question 2

What are the causes of aortic dissection

Answer 2

Common – Hypertension, Trauma, Connective tissue disorder, Aortic Valve Disease, Aortitis

Question 3

What will you find on a history taking of aortic dissection?

Answer 3

Symptoms:
Chest Pain - S (Central Chest), Q (Tearing), I (10), T (Immediate onset, R (Radiating to the back)
Systemic signs: Nausea, vomiting, fatigue

Risk Factors:
Hypertension
Smoking
Recent history of heavy lifting 
Cardiovascular risk factors 
Aortic Valve disease 

Differentials:
MI - Raised Troponin, pain is more crushing, pain comes on over minutes, not immediately
Pericarditis - Pain constant and worse on position
Pneumonia - Productive Cough
PE - Dyspnoea, hypoxia, and pleuritic chest pain.
MSK pain - Very localised, history of trauma
Acute Pancreatitis – Risk Factors E.g. Gallstones, Alcohol

Question 4

What will you find on an examination of a patient with aortic dissection?

Answer 4

End of the bed:
Pale from shock
Hands:
Cool peripheries
Weak Pulse
Reduced capillary refill time
A BP differential between the 2 arms is suggestive and a hallmark feature. 
Tachycardia
Hypotension 
Chest:
Diastolic Murmur – Due to aortic regurgitation 
Abdomen:
Tenderness

Question 5

What investigations will you order in an aortic dissection?

Answer 5

Bedside:
ECG – Aortic dissection commonly causes an inferior MI

Bloods:
Crossmatch – Risk of rupture
Troponin - To rule out MI
FBC - Assess Hb levels for transfusion and rule out infection and
Clotting - They are bleeding
LFT - They are going to theatre, there may be impaired liver function due to hypo-perfusion
U&E - They are going to theatre, there may be impaired renal function due to hypo-perfusion
Amylase – Rule out pancreatitis
ABG – To assess hypo-perfusion and shock, also a good marker of severity

Imaging:
CXR - Mediastinal widening
CT - First line diagnostic imaging
Transoesophageal echo – Another diagnostic imaging modality

Question 6

What is the treatment of an aortic dissection?

Answer 6

Resuscitation:
A-E approach
Get IV Access (2 Large Bore Cannulas)/Give O2 to maintain sats of 94+ /Attach 12 lead ECG
Assessment with AMPLE history and brief examination
Catheterise and monitor fluid output
Get help - Cardio-thoracic surgeon
Refer to ITU
Frequent Observations - Constant or 15 minutely
Don’t treat BP as normal- Permissible hypotension, aim for a BP of 100-120

Medical:
IV Beta Blocker E.g. Labetalol– Hypotensive to reduce blood pressure
Morphine and metoclopramide - Analgesia

Surgical:
Type A - Managed Surgically with removal of ascending aorta and replace with synthetic graft
Type B - Managed medically (continue above treatment) if stable, but may require endovascular stent repair if unstable (Uncontrollable hypertension, Limb Ischaemia, Uncontrollable pain)

What is the chronic treatment?
Lifestyle:
Yearly surveillance of the aorta due to risk of re-dissection.

Medical:
Lifelong antihypertensive therapy