Nontraumatic thoracic aortic dissection

Background

• Incidence estimated 2.6-3.5 per 100,000 person years
• most commonly seen in males, 60-80 yrs old

Risk Factors

• HTN
• Inflammatory vasculitis
• Smoking
• Cocaine
• 3rd trimester pregnancy
• Decelerating trauma
• Connective tissue disorders (Marfan, Ehlers Danlos syndrome)
• Bicuspid aortic valve
• History of surgery (coarctation of aorta repair, aortic valve replacement, cardiac cath)

Classification (Stanford)

• Type A - Involves any portion of ascending aorta
  • Requires surgery
• Type B - Isolated to descending aorta
  • Primarily medical management with surgery consultation

Diagnosis

History

• Chest Pain - Abrupt, severe (90% of pts), classically radiating to back
• Neurologic Deficit
• Syncope (10%)

Physical Exam

• Pulse discrepencies (15%)
• Aortic regurgitation (30%)
• Tamponade
• Neuro - hemiplegia, parapesia, neuropathy (15%)

Studies

• ECG
  • Ischemia - 15%
  • Nonspec ST-T changes - 40%
• CXR
  • Abnormal in 90%
    • Mediastinal widening (seen in 63%)
    • Left sided pleural effusion (seen in 19%)
    • Widening of aortic contour, displaced calcification (6mm), aortic kinking, double density sign
• CT Aortogram
  • Study of choice
• TEE
  • 99% sensitivity, 77% specificity when done alone
  • Can aid in surgical planning with type A dissections

Treatment

• Keep BP 100-120sys, HR 60-80

1. Beta-Blockers
   1. Esmolol
      1. Bolus 0.1-0.5mg/kg over 1min; infuse 0.025-0.2mg/kg/min
   2. Metoprolol
      1. 5mg IV x 3; infuse at 2-5mg/hr
   3. Labetalol
      1. 10-20mg w/ repeat doses of 20-40mg q10min up to 300mg
2. Vasodilators
   1. Only use if beta-blocker is ineffective
   2. Do not use without a beta-blocker
   3. Nitroprusside 0.3-0.5mcg/kg/min

Complications

• AV RegurgitationInsufficiency
  • CHF w/ diastolic murmur
• Rupture
  • Pericardium > tamponade
  • Mediastinum > hemothorax
• Vascular obstruction
  • Coronary > ACS
  • Carotid > CVA
  • Lumbar > Paraplegia
  • Mesenteric, renal, limb

Source

Tintinalli