Aortic dissection

Question 1

Definition

Answer 1

Separation in aortic intima causing blood to enter the media
- Forms a channel in the wall

Question 2

Causes/ Association

Answer 2

Atherosclerosis/ HTN

Connective tissue disorder (weakens the media)
- Marfan’s
- Elhers Danlos

Iatrogenic (rare)
- Cardiac surgery, interventional surgery

Bicuspid aortic valve

Trauma

Pregnancy

Aortic anuerysm

Smoking

Question 3

Pathophysiology
- Most common location of tear

Answer 3

Tear in the intima creates false lumen in media.
- Flow of blood in false lumen can occlude flow in branches of aorta

Most common location of tear
- Above sinotubular junction
- Distal to Left SCA.

Question 4

Standford classifications

Answer 4

Type A (most common)
- Involves ascending aorta
- with/ wo arch and descending

Type B
- Doesn’t involve ascending
- Mainly descending or abdominal (distal to left subclavian)

Question 5

DeBakey classification

Answer 5

Classifies based on original intimal tear and extent of dissection.

Type 1
- Originates in ascending aorta
- Reaches aortic arch + beyond
- Most lethal form

Type 2
- Originates in ascending aorta
- Confined to this region

Type 3
- Originates in descending
- Rarely extends proximally
- Common seen in HTN, atherosclerosis

Question 6

Presentation
- Symptoms
- Signs

Answer 6

Symptoms
- Sudden, tearing chest pain
- Radiates to back (interscapular)
- Nausea
- Abdominal pain

Signs
- Left-right BP differential
- Pulse deficit, especially in proximal tear
- Diastolic murmur (aortic regurg)= crescendo, indicates aortic incompetence
- Syncope
- HTN
- less common (CNS ischaemia): paralysis,/ paraplegia, altered GCS, left pleural effusion

Question 7

Investigations

Answer 7

Gold standard for stable paitent, STAT
- CT angiography (Chest abdomen and pelvis)

Unstable= Echo
- Transthoracic/ transoesophageal

ECG + Cardiac enzymes
- Myocardial Ischaemia/ infarct
- Enzymes usually negative
- May show ST depression

RFT
- Renal perfusion may be compromised

LFTs
- Hepatic perfusion may be compromised (ALT, AST)

Lactate

Group and save + Xmatch

Question 8

Management
- Unstable, medical

Answer 8

1. Noradrenaline
   - With or without dobutamine (beta-1 agonist)
   + Resus

Beta blocker- aim for SBP 100-120
- labetalol, metoprolol, esmolol

2. Vasodilator if BB fails
   - Nitropusside
   - Dilitiazem

Question 9

Surgical management

Answer 9

Type A/ B with complications
- Open surgery/ endovascular stent-graft repair

Open surgery
- Replacement of ascending aorta (and aortic valve)
- Resect/ cover tear in type B dissection

Endovascular
- Fenestrating
- Stenting

Question 10

Long-term management of aortic dissection

Answer 10

Antihypertensives (beta blocker + ACEi first line)
- metoprolol/ enalapril
- second line: add hydrochlorothiazide/ nifedipine