Nontraumatic thoracic aortic dissection

Background

2-3x > men usually 50-70 yrs old

Predisposing factors: Marfans, Ehlers-Danlos, congenital heart dz, pregnancy (third trimester), bicuspid valve (9x), cocaine, decelerating trauma, aortitis (syphilis, Takayasu, giant cell)

RISK FACTOR: Hypertension >>> smoking, cocaine, dyslipidemia

Classification

Stanford:

• Type A - involves ascending Aorta, +/- descending Ao (DeBakey I & II)
• Type B - distal to the origin of the L subclavian a (DeBakey III)

DeBakey:

• Type I - ascending and descending Ao
• Type II - isolated to ascending Ao
• Type III - isolated to descending Ao

Chronic > 2wks otherwise Acute

Diagnosis

History

• Pain - 90% - abrupt
• VasoVagal - sweat, N\V, lt headed
• Neurologic Deficit - 20-40%
• Syncopy - 5-10%

Physical Exam

• Tachycardia
• Pulse Deficits/Discrepencies - (50% of proximal lesions but can be fleeting)
• Aortic Insufficiency
• Tamponade
• Neuro - hemiplegia, parapesia, neuropathy
• Rare - fever unknown origin

Studies

• D-Dimer always elevated (sensitive but not specific)
• ECG - Vent. hypertrophy from HTN, 10-40% may show ischemia or infarction, 33% normal
• CXR - 60-90% mediastinal widening (S/S 67/70), double shadow, aortic knob, CA+ sign rare but specific, pleural effusions
• Echo (TEE) (S/S 97-100/90-100)
• CT & MRI - 95%
• Aortography (S/S 94/88)

Treatment

Keep BP 100-120sys, HR 60-80

1. Nitroprusside (0.5-1.0mcg/kg/min; titrate) & B-blocker eg esmolol (0.5mg/kg loading, 0.05mg/kg/min infusion; titrate)
2. Labetalol (10-20mg IV q10mins, or initial infusion rate at 2mg/min; titrate) or
3. Verapamil

1. Type A - Surgery, unless worsening stroke

2. Type B - Medical, unless uncontrolled BP, Cont Pain, Rupture.

Complications

• Rupture
  • pericardium --> tamponade
  • mediastinum --> hemothorax
• Obstruction of branch vessels
  • coronaries --> acute MI
  • arch vessels --> stroke
  • lumbar --> paraplegia
  • mesenteric, renal, or limb ischemia
• AV Insufficiency
  • diastolic murmur and CHF

Prognosis

Uncomplicated Type B with aggressive medical therapy

• 30 day mortality: 10%
• 5 year mortality: 45-60%

Source

Adapted from Donaldson, Bessen, Pani, DeBonis