Aortic Dissection

Question 1

Describe what an Aortic Dissection is

Answer 1

Failure of the aortic intima (innermost layer of the blood vessel wall). Causes blood to dissect in between the layers of the vessel wall. Blood into this space can extend the tear, create a false lumen and ultimately compromise perfusion at branch vessels or cause rupture.

Question 2

What are the 3 basic morphological of an Aortic Dissection?

Answer 2

• Typical AD: splitting of the aortic intima and media layers
• Penetrating aortic ulcer
• Intramural hematoma: Cresenteric layer of blood forms spontaneously in the aortic wall but without frank separation of the layers or intima flap. Not actually an AD but treated the same way.

Question 3

What are the 4 ways by which mortality occurs from aortic dissection?

Answer 3

• Causes acute cardiac tamponade (b/c intrapericardial rupture of the ascending aorta)
• Acute aortic insufficiency (aka aortic regurg). This produces immediate cardiogenic shock
• Aortic free rupture
• End-organ ischemia (any organ can be affected)

Question 4

Describe the management of ascending aortic dissection vs. descending aortic dissection

Answer 4

• Ascending (Type A of DeBakey Type I and II): Surgery
• Descending (Type B only or DeBakey Type IIIa and IIIb): Medical management. UNLESS there is compromise to a major branch vessel —> then surgery.

Question 5

When is surgery required for descending aortic dissections?

Answer 5

When a major branch vessel is compromised (such as SMA, Renal artery, iliac artery etc.)

Question 6

What are the main risk factors for aortic dissection?

Answer 6

• Uncontrolled HTN!
• Bicuspid aortic valve
• Connective tissue disease
• Cocaine abuse
• Aortic coarctation
• Others: Iatrogenic (cardiac catheterization, AV replacement), thoracic trauma, pregnancy
• Family history of AAA, AD, bicuspid aortic valve, or sudden cardiac death

Question 7

There are many possible physical exam findings to help suggest aortic dissection. What are some exam findings and Hx clues that should really increase your suspicion.

Answer 7

• Tearing/ripping pain
• Migrating pain
• Sudden-onset pain
• Focal neuro deficits
• Pulse deficit (difference of 20 mmHg between arms suggests aortic branch involvement)
• Aortic regurg murmur
• Syncope (suggests tamponade)
• Pulse deficits (check carotid, brachial, and femoral too)
• JVD, muffled heart sounds, puss paradoxes (think tamponade)
• Paraplegia or quadriplegia (suggests involvement of vessels feeding the anterior spinal arteries)

Question 8

Does chest pain with a positive troponin exclude aortic dissection as a diagnosis?

Answer 8

NO

About 18% of patients with AD have an elevated troponin

Question 9

What is the sensitivity and specificity of CT angiogram of the aorta for aortic dissection?

Answer 9

Nearly 100% for both!

Question 10

What are other imaging modalities to use to diagnose aortic dissection if CT is unavailable?

Answer 10

Trans Thoracic Echo - not sensitive, but if you find it then just consult vascular

CXR can give clues

TEE - not recommended because of the need for specialized equipment and training

MRA - highly sensitive and sepcificity, but takes too long and is a specialized exam with limited availability, thus could delay diagnosis.

Question 11

How do you treat Aortic Dissection in the ED?

Answer 11

Hypertensive and Tachycardic?

• Goal SBP: <120
• Goal HR: 60

2 drug strategy:

• Beta-blocker: Esmolol: 500 ug bolus then 50 ug/kg/min infusion up to 300 ug/kg/min max
• Antihypertensive: Nicardipine, Clevidipine, Sodium Nitroprusside, or Fenoldopam

1 drug strategy:

• Labetalol IV 10-20 mg bolus, then 20-80 mg blouses every 10-15 minutes to max 300mg or Labetalol infusion at 0.5-2 mg/min.
• Diltiazem if Beta-blocker is contraindicated.

Immediate surgical consult for ALL dissections (vascular surgery)