Thoracic aortic injury

Last revised by Raymond Chieng on 8 Oct 2023

Thoracic aortic injury is the most common type of traumatic aortic injury and is a critical life-threatening, and often life-ending event. 

Approximately 80% of patients with thoracic aortic injury die at the scene of the trauma. In those who make it to hospital, clinical diagnosis is difficult. The signs and symptoms are non-specific and distracting injuries are often present. Clinical presentation may include chest or mid-scapular back pain, signs of external chest trauma or hemodynamic instability. Clinical suspicion is usually based on mechanism and severity of the injury, the hemodynamic status of the patient and/or the presence of related injuries. The diagnosis ultimately relies on appropriate imaging.

Trauma to the aorta may result in:

An aortic dissection is a longitudinal tear in the aortic wall and is rarely a sequela of trauma.

Blunt thoracic aortic injury is uncommonly an isolated injury. A large autopsy study found that 97% of victims of aortic injury had other traumatic injuries outside the chest 5.

Thoracic aortic injury can be graded according to the severity of injury. One grading system is 6

  • grade 1: intimal tear
  • grade 2: intramural hematoma
  • grade 3: pseudoaneurysm formation
  • grade 4: free rupture

Another system is 7

  • grade I (intimal tears and intramural hematomas)
    • grade Ia: intimal tear
    • grade Ib: intramural hematoma
  • grade II: intimal injury with periaortic hematoma
  • grade III: transection +/- multiple injuries without rupture
    • grade IIIa: aortic transection with pseudoaneurysm
    • grade IIIb: multiple aortic injuries
  • grade IV: free rupture

Thoracic aortic injury can result from either blunt or penetrating trauma:

  1. blunt trauma (more common)
    • rapid deceleration (eg. motor vehicle accident, fall from great height)
    • crush injury
  2. penetrating trauma

The isthmus is the portion of the proximal descending thoracic aorta between the left subclavian artery origin and the ligamentum arteriosum. Tethering of the aorta by the ligamentum arteriosum is believed to account for the high frequency of aortic injury in this region.

The above figures represent the site of injury in those patients who present to hospital. The ascending aorta is injured in 20 -25% of cases at autopsy but most of these patients die at the scene from serious complications such as a ruptured aortic valve, coronary artery laceration or hemopericardium with pericardial tamponade.

A supine chest radiograph is the initial screening investigation in the trauma patient. The mediastinum on a portable supine film can be difficult to assess, especially if taken in expiration or if the patient is rotated. Direct signs of aortic injury are not visible on chest radiographs but indirect signs may be detected: either a mediastinal hematoma or signs of concomitant chest injuries.

Signs of mediastinal hematoma:

  • widened mediastinum (more than 8 cm when supine, or more than 6 cm when upright)
  • indistinct or abnormal aortic contour
  • deviation of trachea, ETT or NGT to the right
  • depression of left main bronchus
  • loss of the aortopulmonary window
  • widened paraspinal stripe
  • widened paratracheal stripe
  • left apical pleural cap
  • large left hemothorax

The detection of mediastinal hematoma on a chest radiograph has a high sensitivity for aortic injury but a low specificity because most mediastinal hematomas are due to other causes such as tearing of mediastinal vessels, sternal injury or thoracic spine injury. Only 12.5% of mediastinal hematomas are due to aortic injury. However, the negative predictive value of a normal chest radiograph of good quality is ~97% but this likely reflects the low incidence of blunt thoracic aortic injury.

May show indirect signs of aortic injury:

  • mediastinal hematoma
  • periaortic fat stranding
  • other chest injuries

CTA is the investigation of choice as it fast and has sensitivity and specificity of 100% at showing direct signs of aortic injury as well as indirect signs.

Signs of mediastinal hematoma:

  • abnormal soft tissue density around mediastinal structures
  • location is important – periaortic hematoma much more suggestive of aortic injury than isolated mediastinal hematoma remote from the aorta.

Signs of aortic injury:

  • intraluminal filling defect (intimal flap or clot)
  • abnormal aortic contour (mural hematoma)
    • sudden change in and/or decreased diameter
  • pseudoaneurysm
  • extravasation of contrast

Rarely performed due to the advent of high-quality CTA.

Signs of aortic injury:

  • resistance in advancing a guidewire
  • intraluminal filling defect (intimal flap or clot)
  • abnormal aortic contour (mural hematoma)
  • pseudoaneurysm
  • extravasation of contrast


  • general risks of angiography
  • dissection or rupture due to guidewire or catheter

Generally not used in the acute setting but can include:

  • MRI
  • transesophageal echocardiography
  • intravascular ultrasound

Aortic injury is a surgical emergency. Treatment is with an aortic stent graft or open repair. Mortality is very high 3:

  • >95% if untreated
  • ~80% die immediately
  • >30% if in hospital and treated

Other causes of widened mediastinum on a chest radiograph:

  • technical factors (supine vs erect)
  • vascular ectasia
  • mediastinal lipomatosis
  • mediastinal masses

Mimics of a mediastinal hematoma on CT include:

Mimics of aortic injury on CTA or conventional angiography:

  • aortic pulsation motion artifact (typically left anterior and right posterior aspects of the ascending aorta)
  • streaming of contrast
  • aortic atheroma
  • ductus diverticulum
  • infundibulum of branch vessel

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Cases and figures

  • Figure 1: illustrations
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  • Figure 2: aorta
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  • Case 1: aortic transection
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  • Case 2: aortic transection
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  • Case 3: post traumatic pseudoaneurysm
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  • Case 4: partial transection and pseduoaneurysm
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  • Case 5
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  • Case 6: post stent repair
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  • Case 7
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  • Case 8
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  • Case 9
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  • Case 9
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  • Case 10: traumatic aortic transection
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  • Case 11
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  • Case 12
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  • Case 13
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