Aortic Dissection

Question 1

What is AD?

Answer 1

• tear in the intimal layer of the aortic wall, causing blood to flow between and splitting apart the tunica intima and media

Question 2

What are the two types of AD?

Answer 2

• Acute
  
  • <=14 days
• Chronic
  
  • >14days

Question 3

What can AD progress to?

Answer 3

• progress distally, proximally, or in both directions from the point of origin.
• Anterograde dissections propagate towards the iliac arteries
• retrograde dissections propagate towards the aortic valve

Question 4

What are the two classifications used for AD?

Answer 4

• Standford Classification
• DeBakey Classification

Question 5

Describe the Stanford classification

Answer 5

• Group A
  
  • DeBakey Types 1&2
  • Involves ascending aorta, can propagate to arch or descending aorta
• Group B
  
  • DeBakey Type 3
  • X involve ascending aorta

Question 6

Describe the DeBakey Classification

Answer 6

• Type I: Involves the ascending aorta, dissection extends into arch and beyond
• Type II: Limited to the ascending aorta (proximal to brachiocephalic artery)
• Type IIIa: Involves the descending thoracic aorta (distal to left subclavian artery, proximal to coeliac artery)
• Type IIIb: Involves descending thoracic aorta and abdominal aorta

Question 7

What are the RF for AD?

Answer 7

• Hypertension
• Atherosclerotic disease
• Male gender
• Connective tissue disorders* (typically Marfan’s syndrome or Ehler’s-Danlos syndrome)
• Biscuspid aortic valve

Question 8

What are the clinical features of AD?

Answer 8

Symptoms

• Chest pain (classically tearing and maximal at onset, though frequently this is not seen)
• Back pain
• Abdominal pain
• Dyspnea
• Syncope / collapse

Signs

• Intra-arm blood pressure differential
• Neurological deficit
• Horners syndrome
• Absent peripheral pulses

Question 9

What are the cx of AD?

Answer 9

• cardiac tamponade
• aortic regurgitation

Question 10

What is the classical triad seen in cardiac tamponade?

Answer 10

Beck’s Triad

• Raised JVP
• Muffled heart sounds
• Hypotension

Question 11

How would acute aortic regurgitation present?

Answer 11

• Diastolic murmur
• Wide pulse pressure
• Signs of heart failure

Question 12

What are the differentials for AD?

Answer 12

• MI
• PE
• Pericarditis
• MSK back pain

Question 13

What Ix would you order for AD?

Answer 13

Bedside

• Bilateral BP - may be different for both
• ECG - may show MI

Bloods

• FBC (leucocytosis may be present)
• U&E
• LFT
• Clotting screen
• D-DIMER (may be elevated)
• Troponin (may be elevated in dissection or indicate the involvement of coronary vessels)
• ABG / VBG
• Group & Save / Cross-match

Question 14

What imaging would you order for AD?

Answer 14

• CXR - widened midiastinum, pericardial effusion
• CT angiogram - definitive imaing
• Aortography - gold standard. but may be inconvinient to perform
• MRI
• Echocardiogram - assess cardiac tamponade & aortic regurgitation

Question 15

How would you mx Standford Type A?

Answer 15

• transfer to cardiothoracic centre
• emergency surgery
  
  • removal of the ascending aorta and replacement with synthetic graft

Question 16

How would you mx Standford Type B?

Answer 16

Uncomplicated Stanford B dissections

• blood pressure mx
• analgesia

Standford B dissections with Cx

• urgent surgery

Question 17

What cx would warrant surgical intervention in Standford Type B?

Answer 17

• rupture
• renal, visceral or limb ischaemia
• refectory pain
• uncontrollable hypertension

Question 18

What are the Cx of AD?

Answer 18

• Aortic rupture
• Aortic regurgitation
• Myocardial ischaemia
• Secondary to coronary artery dissection
• Cardiac tamponade
• Stroke or paraplegia