The aorta can rupture completely or incompletely after blunt or penetrating chest trauma. Signs may include asymmetric pulses or blood pressure, decreased blood flow to the lower extremities, and precordial systolic murmur. Diagnosis is often suspected because of the mechanism of injury and/or chest x-ray findings and confirmed by CT, ultrasonography, or aortography. Treatment is open repair or, more commonly, stent placement.
(See also Overview of Thoracic Trauma.)
Etiology of Traumatic Aortic Disruption
With blunt trauma, the usual mechanism is a severe deceleration injury; patients often have multiple rib fractures, first and/or second rib fractures, or other manifestations of severe chest trauma.
With penetrating trauma, the usual wound traverses the mediastinum (eg, entering between the nipples or the scapulae).
Pathophysiology of Traumatic Aortic Disruption
Complete rupture causes rapid death by exsanguination. Partial disruption with contained rupture tends to occur near the ligamentum arteriosum (see figure Most Partial Ruptures of the Aorta Occur Near the Ligamentum Arteriosum) and to have blood flow maintained, usually by an intact adventitial layer. However, partial ruptures may also cause limited mediastinal hematomas.
Most Partial Ruptures of the Aorta Occur Near the Ligamentum Arteriosum
Symptoms and Signs of Traumatic Aortic Disruption
Patients with traumatic aortic disruption typically have chest pain.
Signs can include upper extremity pulse deficits, a harsh systolic murmur over the precordium or posterior interscapular space, hoarseness, and evidence of impaired blood flow to the lower extremities, including decreased pulse strength or blood pressure in the lower extremities compared to the upper extremities.
Diagnosis of Traumatic Aortic Disruption
Aortic imaging
Traumatic aortic disruption should be suspected in patients with a suggestive mechanism or suggestive chest x-ray findings.
Suggestive chest x-ray findings include the following:
Widened mediastinum (high sensitivity except among older patients)
First or second rib fracture
Obliteration of the aortic knob
Deviation of the trachea or esophagus (and thus also any nasogastric tube) to the right
Depression of the left mainstem bronchus
Pleural or apical cap (typically on the left)
Hemothorax, pneumothorax, or pulmonary contusion
However, some of these suggestive chest x-ray findings may not be present immediately. Also, no finding or combination of findings is sufficiently sensitive or specific; thus, many authorities recommend aortic imaging for all patients who have had a severe deceleration injury, even in the absence of suggestive findings on examination or chest x-ray.
The aortic imaging study of choice varies by institution. Studies that are reasonably accurate include the following:
CT angiography: Immediately available (in most trauma centers) and rapid.
Aortography: Considered the most accurate but is invasive (resulting in a higher complication rate) and takes longer to complete (usually 1 to 2 hours).
Transesophageal echocardiography is no longer used as an initial imaging study, but it may be performed intraoperatively if the patient is undergoing abdominal surgery and hemodynamics are not explained by the abdominal findings. Transesophageal echocardiography has a low complication rate and can detect certain associated injuries (eg, to the innominate vessels) that can be missed on CT.
Treatment of Traumatic Aortic Disruption
Blood pressure and heart rate control
Surgical repair or stent placement
≤ 90 beats/minute and systolic blood pressure ≤
Endovascular stent placement is now the treatment of choice for repairing traumatic aortic disruption. Repair can be delayed while evaluating and treating other potentially life-threatening injuries.
Key Points
Partial disruption of the aorta should be considered in patients with a chest injury caused by severe deceleration.
Chest x-ray abnormalities are common but may be absent and are often nonspecific; better aortic imaging studies include CT angiography and aortography.
Control heart rate and blood pressure (usually with a beta-blocker) and place an endovascular stent for definitive repair.
