In the United States, trauma remains the leading cause of death in those less than 44 years of age, and for those older than 45, trauma is one of the top five causes of death. Of all injuries sustained in a trauma, the aortic injury is one of the most time-sensitive, life-threatening conditions, second only to head injury as a cause of death. The morbidity and mortality associated with traumatic aortic injury are about 30% within the first 24 hours. Some predisposing factors for traumatic aortic injury include; penetrating chest injuries, deceleration injuries, and blunt chest trauma. There are no clinical findings specific for aortic injury. However, hypotension, external evidence of trauma, and altered mental status are common. Many patients with complete transection of the thoracic aorta die before arriving at the emergency department (ED). Those who survive arrival in the ED may have small tears or partial-thickness tears of the aortic wall with a pseudo-aneurysm formation. The survival of patients after traumatic aortic injury depends on a clinician’s high index of suspicion, rapid diagnosis, and prompt management.
Blunt force trauma is more common. This involves rapid deceleration mechanisms such as motor vehicle accidents or falls from great heights. Aortic trauma can also be caused by penetrating traumas, such as stab injury and firearm injury.
It is the second most common cause of death in patients with blunt force trauma (head trauma is the most common). Over 80% of those with aortic injury die at the scene. Up to 15% of all deaths following motor vehicle collisions are due to injury to the thoracic aorta.
The aorta has some fixed regions, particularly the relatively fixed aortic arch (to the thoracic inlet by the brachiocephalic vessels). The remaining portions of the aorta are relatively free. Ascending and descending aorta are relatively mobile. These can result in an unequal distribution of shear forces on the relatively fixed arch and mobile ascending and descending aorta and stress at the site of attachment of the aorta, particularly the aortic root and the aortic isthmus.
The most common sites of injury are the following:
Major mechanisms involved in aortic trauma injuries are as follows:
Type of injury:
Beware that delayed adventitial rupture may occur during hospitalization.
There are no clinical findings specific for aortic injury. However, hypotension, external evidence of trauma, and altered mental status are common.
The symptoms may include the following:
Be aware that symptoms may not reliably predict aortic injury.
Clinical suspicion should be based on mechanism and severity of the injury, the hemodynamic stability of the patient and/or the presence of associated injuries. The possibility of aortic injuries should be considered and excluded in patients with a history of a falls from heights or high-speed motor vehicle crashes.
Although this has a low sensitivity, it is used as a primary screening test and often determines whether additional imaging is required.
The following findings may be present in patients with aortic injury; but, they are not diagnostic.
Beware that it is difficult to assess these findings on a supine, portable chest radiograph.
Although FAST examination is required to evaluate any intra-abdominal injury, it may not provide adequate information about the aortic injury, since it does not include the aorta.
The decision of whether to obtain a CT scan or angiography depends on institutional preferences, the patient's status, and the presence of associated injuries. CT scan is an initial screening modality for patients where the mechanism of injury may suggest this type of injury. In recent years, newer generation multi-detector helical CT scans have replaced angiography.
Currently, CT angiography is increasingly used, and it is the investigational modality of choice. Most experts agree that a negative CT-angiogram may obviate the need for angiography. It should be obtained in patients who are involved in high-speed accidents, to exclude aortic injury.
For mediastinal hematoma, the following signs may be seen:
The following signs may suggest aortic injury:
The severity of the aortic injury is classified as follows:
Treatment of an aortic injury is a surgical emergency. The survival of patients following a traumatic aortic injury depends on early recognition, rapid diagnosis, and prompt management. Surgical repair of the injured thoracic aorta is associated with a high mortality and morbidity. The initial resuscitation includes ABCDE, based upon Advanced Trauma Life Support (ATLS) principles: If any life-threatening condition is identified, it should be immediately treated.
Assessment of associated injuries includes:
Management decisions for patients with aortic injury depend on the following:
Associated injuries and medical conditions: beware that despite having a contained aortic injury, the patient may be hemodynamically unstable due to hemorrhage from other organs, such as liver or spleen. Hemorrhage control is still the priority. However, if the aorta is not the cause of active hemorrhage, control of active bleeding should be the priority.
Indications for operative repair are as follows:
Surgical treatment is by either primary repair of the aorta or resection of the injured segment and grafting. The repair of aorta should not be delayed beyond the time required to evaluate and treat other emergent conditions. The aortic repair can be performed by either an open or endovascular method. Since the endovascular technique is not widely available, its role in the treatment of traumatic aortic disruption has yet to be determined.
Aortic trauma is not an uncommon presentation to the emergency department. The condition needs a prompt referral to a thoracic or vascular surgeon. Because of the risk of rupture and a high mortality, the condition is best managed by a multidisciplinary team that includes an emergency department physician, trauma surgeon, thoracic surgeon, interventional radiologist, vascular surgeon, and an intensivist. Once diagnosed the two options for repair include open surgery or an endovascular procedure. The patient should be closely monitored in an ICU setting after surgery. The biggest risk of surgery is paraplegia, which even in the best of hands occurs at a rate of 5-10%. (level V)