Question 13

College answer

Not available.

Discussion

The question asked "explain", not "list", which means a bit of discourse is called for:

Medical management:

• Overall management goals:
  • Decrease aortic wall stress 
  • Thus, reduce the risk of rupture
  • Decrease the risk of propagation of the dissection flap
  • Maintain the perfusion of compromised organs
• Haemodynamic objectives which serve these goals: 
  • Decrease cardiac contractility (dP/dT)
  • Decrease blood pressure
  • Decrease heart rate
• Options to achieve these goals:
  • Labetalol infusion (15mg bolus, then 5mg/hr)
  • Alternatively, esmolol, verapamil, diltiazem
  • Once contractility and rate control is achieved,
    vasodilators can also be used (nitroprusside, clevidipine, etc)
  • Analgesia +/- sedation to decrease sympathetic output
• Endpoints of therapy:
  • Systolic blood pressure 100-120 mmHg
  • HR < 70
  • Improved surrogate measures of organ perfusion

Indications for surgical management:

• Complicated Type B dissection:
  • Features suggesting instability:
    • Aortic rupture
    • Refractory hypertension
    • Aortic total diameter of > 4.5 cm
    • Extension of dissection on repeat imaging
  • Ischaemia:
    • Visceral and renal ischaemia
    • Lower extremities ischaemia
    • Spinal cord ischaemia
  • Malperfusion:
    • Paraparesis or paraplegia
    • Abdominal pain, nausea, or diarrhea
    • Renal failure or LFT derangement
• Uncomplicated Type B dissection
  • Can usually be managed conservatively
  • If the aorta is dilated (>4cm) or the false lumen is large (>22mm), surgical management may still be preferred to prevent long-derm aneurysmal degeneration