see also:

• chest pain in the ED;
• ADD - an aortic dissection risk assessment tool
• Features and diagnosis of aortic dissection
• AFTB lecture notes - aortic dissection

• mortality in 1st 24-48hrs is 1-2% per hour
• all pts with suspected dissection should have careful monitoring of:
  • ECG
  • BP - preferably with arterial line
  • urine output
• IV opiate analgesia

• objectives of early Mx are to eliminate forces favoring progression ASAP whilst Dx tests are performed:
  • maintain BP between 100-120mmHg systolic or lowest commensurate with vital organ perfusion:
    • options:
      • IV sodium nitroprusside infusion if no C/I to beta blockers:
        • 0.5-3ug/kg/min
      • IV trimethaphan if C/I to beta blockers:
        • 1-2mg/min
      • IV labetalol has also been used as a single agent:
        • 10-20mg bolus, repeat prn until BP controlled, then infusion 1-2mg/min
      • see also: Antihypertensive agents
  • reduce force of cardiac contraction & rate of rise of arterial pulse (dP/dT):
    • beta blocker options (esp. if nitroprusside used):
      • IV propranolol 1mg every 5min (max. 0.15mg/kg) aiming to reduce heart rate to 60-80bpm
        • then additional doses 2-6mg 4-6hrly IV
      • IV metoprolol
      • IV esmolol infusion
• some patients develop hypotension (30-40%), which is most commonly due to cardiac tamponade but there are limited safe options for the Rx of this within the ED, and one is largely restricted with the Rx option of iv fluids aiming to keep systolic BP > 70mmHg whilst awaiting definitive surgery
  • vasopressors have the potential to cause further false lumen propagation.
  • inotropic agents are likely to increase the force and rate of ventricular contraction and thus increase sheer stress on the aortic wall.
  • pericardiocentesis has been associated with recurrent pericardial bleeding and increased mortality. For patients with obvious cardiac tamponade who cannot survive until surgery, pericardiocentesis may be performed by withdrawing just enough fluid to restore perfusion.
  • other complications that may result in hypotension include severe dissection-related aortic regurgitation, true lumen obstruction by a compressing false lumen, acute MI and rupture of the false lumen into adjacent structures. All require definitive operative management.

• Type A dissections require surgical Rx
  • refer to cardiothoracic services ASAP
  • operative mortality 7%
  • if aortic regurg. present, then correction via valve resuspension or replacement
  • immediate Sx repair C/I if concurrent progressing stroke
• Rx of Type B dissections is less clear:
  • tend to have worse surgical risks
  • usually managed by vascular surgical unit
  • hospital mortality in pts Rx without surgery with acute dissections is 15-20%
  • comparable to or better than surgical mortality in most institutions, although it is decreasing
  • BP control
  • surgery if:
    • persistent pain
    • uncontrolled HT
    • occlusion of major arterial trunk
    • frank aortic leaking/rupture
    • development of localised aneurysm

• these pts have survived their period of greatest mortality risk, thus usually Rx medically with BP control:
  • usually beta blockers +/- diuretics, Ca channel blockers, ACEIs
• follow up visits for:
  • BP monitoring
  • detecting signs of progression or recurrence incl. CCF, aortic regurg.
  • CXRs to monitor mediastinal size
  • periodic CT or MRI
• unless complications mandate Sx:
  • re-dissection
  • development of localised aneurysm
  • progressive aortic insufficiency