Traumatic aortic transection

Not to be confused with nontraumatic thoracic aortic dissection

Background

Aortic sebments.

Branches of the aorta.

Aortic isthmus laceration with pseudoaneurysm (arrow), mediastinal hematoma, and bilateral hemothorax

• Blunt traumatic mechanism, rapid deceleration
• Most common location is isthmus (90%) just distal to the left subclavian artery
  • Where the ligamentum arteriosum tethers the aorta and pulmonary artery
  • Other locations are:
    • Ascending aorta (5%)
    • Diaphragmatic hiatus (5%)
• Often asymptomatic but die without warning (80% die at scene)
• Do NOT have Hypotension (just die, but may have initial hypertension in upper extremities)
• Need high suspicion to diagnose

Clinical Features

No signs or symptoms are sufficiently sensitive for dignosis

Symptoms

• Chest pain
• Back pain
• Shortness of breath
• Dysphagia

Physical exam

• Seatbelt or steering wheel sign
• New murmur
• Subclavian hematoma
• Femoral pulse discrepancy
• Upper extremity hypertension if isolated traumatic aortic transection
  • Aortic hematoma stretches sympathetic fibers, increasing systemic vascular resistance
  • Patients either have moderately elevated BP or no blood pressure at all, as true rupture leads quickly to death

Differential Diagnosis

Thoracic Trauma

• Airway/Pulmonary
  • Bronchial injury
  • Diaphragmatic trauma
  • Hemothorax
  • Pneumomediastinum
  • Pulmonary contusion
  • Tracheal injury
  • Trachobronchial injury
  • Traumatic pneumothorax
    • Tension pneumothorax
• Cardiac/Vascular
  • Cardiac injury
    • Blunt cardiac injury
      • Cardiac contusion
      • Commotio cordis
    • Penetrating cardiac injury
    • Cardiac tamponade
  • Traumatic aortic transection
• Musculoskeletal
  • Clavicle fracture
    • Clavicle fracture (peds)
  • Rib fracture
    • Flail chest
  • Scapular fracture
  • Scapulothoracic dissociation
  • Sternoclavicular dislocation
  • Sternum fracture
  • Thoracic and lumbar fractures and dislocations
• Other
  • Esophageal injury or Perforation
  • Pneumomediastinum
  • Pneumopericardium
  • Traumatic asphyxia

Evaluation

Workup

Blunt thoracic aortic injury on CXR showing widened mediastinum

Acute  traumatic  aneurysm: small focal outpouching from the anterior aspect of the proximal descending thoracic aorta (curved arrow).

Traumatic dissection of the descending aorta. (a) Proximal border at the level of the isthmus. (b) Involvement of the abdominal part

• CT
  • Diagnostic study of choice
  • Good for aorta but not for branch vessels
• CXR (may be an initial screening study, but is not sensitive)
  • Widened mediastinum (>8cm on supine film)
  • Left apical cap
  • Enlarged aortic knob
  • Left hemothorax
  • Rightward tracheal/esophageal deviation
  • Depression of left mainstem bronchus
  • Elevation of right mainstem bronchus
  • Widened paratracheal stripe
  • Widened paraspinal interfaces
• Aortography
  • No longer routinely performed, although previously the gold standard
  • 25% have complications (i.e. infection & hematoma)

Diagnosis

Classification

(a) Grade 1: Intimal flaps at the level of the proximal descending aorta and 10 cm distal to the subclavian artery (arrowheads) with accompanying mediastinal hematoma. (b) Grade 3: large pseudoaneurysm formation. (c) and (d) Traumatic aortic transection (grade 4) with massive para-aortic hematoma.

Based on CT findings

• Type I: Intimal tear
• Type II: Intramural hematoma
• Type III: Pseudoaneurysm
• Type IV: Rupture (free rupture, periaortic hematoma)

Management

• Management per ATLS for multiple injuries, hypotension
• Initial medical management similar to Nontraumatic thoracic aortic dissection
• Keep SBP <120, HR 60-80 with α/β-blockers, calcium-channel blockers
• Type I injuries may be managed conservatively
• Surgical management for type II and greater

Disposition

• Admission

See Also

• Thoracic trauma
• Nontraumatic thoracic aortic dissection