Thoracic aortic injury
Updates to Synonym Attributes
Updates to Synonym Attributes
Updates to Article Attributes
Thoracic aortic injury is a life threatening, and often life ending event. It can result from either blunt or penetrating trauma:
- blunt trauma (more common)
- rapid deceleration (eg. motor vehicle accident, fall from great height)
- crush injury
- penetrating trauma
- stab wound
- gunshot wound
Clinical presentation
Approximately 7080% 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 haemodynamic instability. Clinical suspicion is usually based on mechanism and severity of the injury, the haemodynamic status of the patient and/or the presence of related injuries. The diagnosis ultimately relies on appropriate imaging.
Pathology
Trauma to the aorta may result in:
-
aortic laceration
- a: a tear in the intima which may extend through the vessel wall; the tear is typically transverse -
aortic transection:
- lacerationlaceration of all three layers of the vessel wall, also known as aortic rupture -
aortic pseudoaneurysm
- aortic: aortic rupture contained by adventitia or periaortic tissue -
aortic intramural haematoma
- haematoma
An aortic dissection is a longitudinal tear in the aortic wall and is rarely a sequelae of trauma.
Site
- aortic isthmus
- 90: 90% -
ascending aorta
- 5: 5% - diaphragmatic hiatus
- 5: 5%
The isthmus is 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 to 25-25% 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 haemopericardium with pericardial tamponade.
Radiographic features
Plain film - chest radiograph
Initial screening investigation in the trauma patient. The mediastinum on a portable supine film may difficult to assess, especially if taken in expiration or if the patient is rotated. Direct signs of aortic injury are not visible on CXRchest x-ray (CXR) but indirect signs may be detected: mediastinal haematoma, other chest injuries.
Signs of mediastinal haematoma:
- widened mediastinum
- indistinct or abnormal aortic contour
- deviation of trachea or NGT to the right
- depression of left main bronchus
- widened paraspinal stripe
- left apical pleural cap
The detection of mediastinal haematoma on CXR has a high sensitivity for aortic injury but a low specificity because most mediastinal haematoma is due to other causes such as tearing of mediastinal vessels, sternal injury or thoracic spine injury. Only 12.5% of mediastinal haematoma is due to aortic injury. However, the negative predictive value of a normal CXR of good quality is ~97%.
CT
Non-contrast CT chest
May show indirect signs of aortic injury:
- mediastinal haematoma
- periaortic fat stranding
- other chest injuries
CTA chest
The investigation of choice. Excellent at showing direct signs of aortic injury as well as indirect signs - sensitivity 100%; specificity 100%.
Signs of mediastinal haematoma:
- abnormal soft tissue density around the mediastinal structures
- location is important – periaortic haematoma much more suggestive of aortic injury than isolated mediastinal haematoma remote from the aorta.
Signs of aortic injury:
- intraluminal filling defect (intimal flap or clot)
- abnormal aortic contour (mural haematoma)
- pseudoaneurysm
- extravasation of contrast
Conventional angiography
Rarely performed due to the advent of high quality CTA.
Signs of aortic injury:
- resistance in advancing guidewire
- intraluminal filling defect (intimal flap or clot)
- abnormal aortic contour (mural haematoma)
- pseudoaneurysm
- extravasation of contrast
Complications:
- general risks of angiography
- dissection or rupture due to guidewire or catheter
Other imaging methods
Generally not used in the acute setting:
- MRI
- transoesphageal echocardiography
- intravascular ultrasound
Treatment and prognosis
Aortic injury is a surgical emergency. Treatment is with an aortic stent graft (see Case 6) or open repair. Mortality is very high 3:
- >95% if untreated
- ~80% die immediately
- >30% if in hospital and treated
Complications
- death from aortic rupture and haemorrhage
- chronic traumatic pseudoaneurysm
- embolisation from pseudoaneurysm
Differential diagnosis
Other causes of widened mediastinum on a chest radiograph
- technical factors
- vascular ectasia
- mediastinal lipomatosis
- mediastinal masses
Mimics of a mediastinal haematoma on CT include
- artefact
- thymic tissue
- unopacified vessels
- pericardial recesses
- paramediastinal lung atelectasis
Mimics of aortic injury on CTA or conventional angiography
- artefact
- streaming of contrast
- aortic atheroma
- ductus diverticulum
- infundibulum of branch vessel
See also
-<li><a href="/articles/gun-shot">gun shot wound</a></li>- +<li><a href="/articles/imaging-of-gun-shot-injuries">gunshot wound</a></li>
-</ol><h4>Clinical presentation</h4><p>Approximately 70% of patients with <a href="/articles/thoracic-aorta">thoracic aortic</a> 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 haemodynamic instability. Clinical suspicion is usually based on mechanism and severity of the injury, the haemodynamic status of the patient and/or the presence of related injuries. The diagnosis ultimately relies on appropriate imaging.</p><h4>Pathology</h4><p>Trauma to the <a href="/articles/aorta">aorta</a> may result in:</p><ul>- +</ol><h4>Clinical presentation</h4><p>Approximately 80% of patients with <a href="/articles/thoracic-aorta">thoracic aortic</a> 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 haemodynamic instability. Clinical suspicion is usually based on mechanism and severity of the injury, the haemodynamic status of the patient and/or the presence of related injuries. The diagnosis ultimately relies on appropriate imaging.</p><h4>Pathology</h4><p>Trauma to the <a href="/articles/aorta">aorta</a> may result in:</p><ul>
-<a href="/articles/aortic-laceration">aortic laceration</a> - a tear in the intima which may extend through the vessel wall; the tear is typically transverse</li>- +<a href="/articles/aortic-laceration">aortic laceration</a>: a tear in the intima which may extend through the vessel wall; the tear is typically transverse</li>
-<a href="/articles/aortic-transection">aortic transection</a><strong> </strong>- laceration of all three layers of the vessel wall, also known as <a href="/articles/aortic-rupture">aortic rupture</a>- +<a href="/articles/aortic-transection">aortic transection</a><strong>:</strong> laceration of all three layers of the vessel wall, also known as <a href="/articles/aortic-rupture">aortic rupture</a>
-<a href="/articles/aortic-pseudoaneurysm">aortic pseudoaneurysm</a> - aortic rupture contained by adventitia or periaortic tissue</li>- +<a href="/articles/aortic-pseudoaneurysm">aortic pseudoaneurysm</a>: aortic rupture contained by adventitia or periaortic tissue</li>
-<a href="/articles/aortic-intramural-haematoma">aortic intramural haematoma</a><strong> </strong>- haematoma within the wall of the aorta</li>- +<a href="/articles/aortic-intramural-haematoma">aortic intramural haematoma</a>: haematoma within the wall of the aorta</li>
-<li>aortic isthmus - 90%</li>- +<li>aortic isthmus: 90%</li>
-<a href="/articles/ascending-aorta">ascending aorta</a> - 5%</li>-<li>diaphragmatic hiatus - 5%</li>-</ul><p>The isthmus is portion of the proximal descending thoracic aorta between the left <a href="/articles/subclavian-artery">subclavian artery</a> origin and the <a href="/articles/ligamentum-arteriosum">ligamentum arteriosum</a>. Tethering of the aorta by the ligamentum arteriosum is believed to account for the high frequency of aortic injury in this region.</p><p>The above figures represent the site of injury in those patients who present to hospital. The ascending aorta is injured in 20 to 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 haemopericardium with <a href="/articles/pericardial-tamponade">pericardial tamponade</a>.</p><h4>Radiographic features</h4><h5>Plain film - chest radiograph</h5><p>Initial screening investigation in the trauma patient. The mediastinum on a portable supine film may difficult to assess, especially if taken in expiration or if the patient is rotated. Direct signs of aortic injury are not visible on CXR but indirect signs may be detected: mediastinal haematoma, other chest injuries.</p><p>Signs of mediastinal haematoma:</p><ul>- +<a href="/articles/ascending-aorta">ascending aorta</a>: 5%</li>
- +<li>diaphragmatic hiatus: 5%</li>
- +</ul><p>The isthmus is portion of the proximal descending thoracic aorta between the left <a href="/articles/subclavian-artery">subclavian artery</a> origin and the <a href="/articles/ligamentum-arteriosum">ligamentum arteriosum</a>. Tethering of the aorta by the ligamentum arteriosum is believed to account for the high frequency of aortic injury in this region.</p><p>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 haemopericardium with <a href="/articles/pericardial-tamponade">pericardial tamponade</a>.</p><h4>Radiographic features</h4><h5>Plain film - chest radiograph</h5><p>Initial screening investigation in the trauma patient. The mediastinum on a portable supine film may difficult to assess, especially if taken in expiration or if the patient is rotated. Direct signs of aortic injury are not visible on chest x-ray (CXR) but indirect signs may be detected: mediastinal haematoma, other chest injuries.</p><p>Signs of mediastinal haematoma:</p><ul>
-</ul><h4>Treatment and prognosis</h4><p>Aortic injury is a surgical emergency. Treatment is with an aortic stent graft (see Case 6) or open repair.</p><h5>Complications</h5><ul>- +</ul><h4>Treatment and prognosis</h4><p>Aortic injury is a surgical emergency. Treatment is with an aortic stent graft or open repair. Mortality is very high <sup>3</sup>:</p><ul>
- +<li>>95% if untreated</li>
- +<li>~80% die immediately</li>
- +<li>>30% if in hospital and treated</li>
- +</ul><h5>Complications</h5><ul>
-</ul><h4>See also</h4><ul><li><a href="/articles/traumatic-aortic-injury-in-the-exam">traumatic aortic injury in the exam</a></li></ul>- +</ul>
References changed:
- 3. Steenburg SD, Ravenel JG. Acute traumatic thoracic aortic injuries: experience with 64-MDCT. AJR Am J Roentgenol. 2008;191 (5): 1564-9. <a href="http://dx.doi.org/10.2214/AJR.07.3349">doi:10.2214/AJR.07.3349</a> - <a href="http://www.ncbi.nlm.nih.gov/pubmed/18941102">Pubmed citation</a><span class="auto"></span>
- 4. O'Conor CE. Diagnosing traumatic rupture of the thoracic aorta in the emergency department. Emerg Med J. 2004;21 (4): 414-9. <a href="http://emj.bmj.com/content/21/4/414.full">Emerg Med J (full text)</a> - <a href="http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1726377">Free text at pubmed</a> - <a href="http://www.ncbi.nlm.nih.gov/pubmed/15208221">Pubmed citation</a><span class="auto"></span>
Image 10 CT (C+ arterial phase) ( create )
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