Condition- Aortic Dissection

Question 1

What is an aortic dissection?

Answer 1

A condition where a tear in the aortic intima allows blood to surge into the aortic wall, causing a split between the inner and outer tunica media, creating a false lumen

Question 2

What are the two classifications of aortic dissection and which is the most common?

Answer 2

1. Type A: ASCENDING Aorta: Most common (70%)
2. Type B: DESCENDING Aorta: Less common (30%) Distal to the subclavian artery

Question 3

Descirbe the pathophysiology of aortic dissection

Answer 3

1. An intimal tear is the initial event
2. Subsequent degeneration of the medial layer of the aortic wall
3. Blood then passes through the media, propagating distally or proximally and creating a false lumen
4. As the dissection propagates, flow through the false lumen can occlude flow through branches of the aorta

Question 4

List some risk factors for developing Aortic Dissection. What is the main RF?

Answer 4

• HYPERTENSION-often poorly controlled
• Aortic Atherosclerosis
• Smoking
• Usually in their 50s
• Iatrogenic- angioplasty etc.
• Younger patients may have:
  
  • Connective-tissue disorder (SLE, Marfan’s, Ehlers-Danlos)
  • Recent history of heavy lifting
  • cocaine use
  • Congenital cardiac abnormalities
• FHx of aortic aneurysms, dissection, or a connective-tissue disorder

Question 5

Describe the chest pain experienced by someone with aortic dissection

Answer 5

• S: Central
• O: Acute onset
• C: TEARING or RIPPING chest pain
• R: May radiate to the back in between the shoulder blades
• S: severe

Question 6

Describe some of the other symptoms that may be experienced dependent on which branches of the aorta are obstructed.

* Go through the different branches and think about what could happen if they were occluded

Answer 6

• Carotid: Hemiparesis, dysphasia, syncope
• Coronary: Chest Pain (MI)
• Subclavian: Ataxia, loss of consciousness
• Anterior Spinal: paraplegia
• Coeliac: Abdo pain
• Renal: Anuria, renal failure

Question 7

List some of the signs of Aortic Dissection on physical examination

Answer 7

• Distolic Murmur on the back below left scapula (crescendo pattern)
• Blood pressure differences >20mmHg between two arms
• Wide pulse pressure
• Hypertension
• Signs of aortic regurgitation:
  
  • High volume collapsing pulse
  • Early DBP over aortic area
• May be palpable abdo mass

Question 8

A difference in blood pressure greater than xmmHg between the two arms is suggestive of aortic dissection?

Answer 8

20mmHg

Question 9

Why might you get hypotension in a patient with aortic dissection. How could you check for this

Answer 9

Hypotension may suggest tamponade

Check for pulsus paradoxus = abnormally large decrease in systolic blood pressure and pulse wave amplitude during inspiration

Question 10

Which investigations could you order for someone with suspected aortic dissection? What is the GOLD STANDARD + FIRST LINE investigation?

Answer 10

1. CT and Echocardiography- can visualise intimal flap
2. ECG- to rule ou Myocardial Ischaemia. Should be normal. If MI get ST elevation or ST depression+ T inversion
3. Bloods
   
   • FBC- anaemia
   • X-match
   • U&Es: renal function
   • LFTs: clotting screen too
   • Lactate: indicates malperfusion
   • Cardiac enzymes: to rule out MI
4. CXR
   
   • Rule out pulmonary causes. May also see widened mediatinum