Blunt Aortic Injury
I’m Ed Smith, a Sacramento Car Accident Lawyer. Most people who sustain a major injury to the aorta during a blunt aortic injury die instantly. Of those who survive to make it to the hospital, many die during the initial management of the condition and don’t make it to surgery. Hemorrhage from other nearby veins or rib fractures, vertebral fractures, or sternal fractures can mimic an aortic injury. Most aortic injuries are tears straight across the aorta with smooth edges. The injury can be as slight as a tear of the inner lining of the aorta to a complete transection of the aorta. Sometimes these injuries may be called cardiac contusions.
As a Sacramento Car Accident Lawyer, I’ve seen my fair share of these tragic injuries. The blunt aortic injury is the most lethal of all chest trauma injuries. The major risk factors include the following:
- Being in the front seat
- Being older than age 60
- Not wearing a seat belt restraint
- Front or near-side motor vehicle crashes
- Abrupt deceleration injury
- Crushed vehicle
- Intrusion into the passenger space
- Being hit by an SUV
Getting Properly Diagnosed Right Away
Patients who fall more than ten feet or are involved in a rapid deceleration injury from a motor vehicle crash over 40 miles per hour are at the greatest risk for sustaining a blunt aortic injury. Almost 80 percent of the time, death is immediate because the aorta is transected completely through. In a small minority of patients, the structures around the aorta contain the rupture so that the patient survives the trip to the hospital. If the blunt aortic trauma is not diagnosed, the patient usually suffers a rupture within a day. Prompt evaluation and management of these patients is vital and may save some of their lives.
Proper Clinical Testing
There are no sensitive clinical signs or findings on examination that can detect a blunt aortic injury. This means that the doctor should use x-ray studies and CT scans to assess every patient who has sustained a high energy trauma with severe chest injury or a mechanism of injury that involves rapid deceleration. The initial study should be a chest x-ray, which should be looked at carefully for signs of an aortic trauma.
Good News When the Chest X-Ray is Negative
If the chest x-ray is negative, there is very little chance that a blunt aortic trauma exists. In such cases, no further studies are needed. If the chest x-ray is suspicious, a CT scan of the chest should be done. If this is normal, it usually means nothing further needs to be done in the way of more testing. If there is a strong suspicion of acute aortic injury, even if the chest x-ray is negative, a CT scan should be checked.
Other Clinical Testing
Other tests for blunt traumatic injury to the aorta include an angiogram and transesophageal echocardiography. Angiography is the gold standard evaluation; however, it should be reserved for people who have equivocal CT scans of the chest. It is more time consuming than a CT scan and is also more invasive and rarely adds to the management if the CT scan is suspicious.
Suspicion of Blunt Aortic Injury
A CT scan of the chest should be done whenever there is clinical suspicion of a blunt aortic injury. This includes the following situations:
- A high energy impact with rapid deceleration
- Chest wall deformity or bruising
- Multiple fractures of the ribs
- Abnormal chest x-ray on initial evaluation
Contrast CTs are Best
The chest CT with contrast has the best sensitivity and specificity for blunt aortic trauma and is the test most likely to make the diagnosis of injury. It also helps determine if there are other chest injuries.
When the Chest X-ray is Abnormal
If the chest x-ray is abnormal, the chest CT can identify the source of the abnormality about 20-30 percent of the time. If the CT scan is done just because the mechanism of injury dictates it should be done, findings are noted only about 5 percent of the time. The angiogram should only be done if the CT scan has been found to be equivocal.
Another Excellent Test for Blunt Aortic Injury
Transesophageal echocardiography or TEE is an excellent test for blunt aortic injury in patients too unstable to go for a chest CT. It can be done in the emergency department or in the operating room and requires no contrast. It can also tell if the heart and its function are normal. It shouldn’t be done in cases of unstable cervical spine trauma or injuries to the esophagus.
Test Able To Diagnose Tears
The transesophageal echocardiogram compares favorably to the other studies in most cases and is able to diagnose some tears of the inner lining of the aorta not seen on angiography, although this may not be clinically significant. It can also help diagnose injuries to the heart valves and fluid around the heart. Transthoracic echocardiography, on the other hand, can successively diagnose significant pericardial effusions but can’t reliably diagnose a blunt aortic injury.
Those with blunt aortic injury waiting to be treated in the operating room need careful blood pressure and heart rate control. This means keeping the blood pressure as low as possible and treating the heart rate so it is as slow as possible without causing shock.
Repair of Blunt Aortic Injury
Repair of the injured aorta includes an open repair via a thoracotomy (opening up of the chest) or through repair from the inside of the blood vessel. In some cases, it is not feasible to do emergency surgery. Immediate aortic repair may not be appropriate for those who have other injuries to their lungs, heart, or head.
Sometimes Delay in Repair of Blunt Aortic Injury is an Option
Delayed repair is an option for those patients that have stable vital signs and no evidence of impending rupture of the aorta, a blood clot in the aorta, blockage of the aorta, or a large hemothorax. During the waiting period, the heart rate and blood pressure need to be in tight control.
Postoperative outcomes seem to be better when the individual has a delayed repair when compared to individuals who have immediate repair. The risk of death and paraplegia are higher in those who have early repair when compared to those who have later repair of their aortic injury.
As mentioned, there are two types of blunt aortic injury repair:
- Open repair. A tube prosthetic graft is placed over the aorta through open surgery.
- Endovascular repair. Access is through the iliac or femoral arteries and the repair is made inside the damaged blood vessel itself. A graft can also be used but it is put on the inside of the blood vessel.
In endovascular repair, the outcomes after thirty days appear to be improved compared with open surgery. The long term effect of endovascular stenting in this younger population of patients needs further study.
Follow up and Mortality
Bunt aortic injury is a major cause of death in blunt chest trauma. It is responsible for 16 percent of deaths in which the individual sustained a blunt chest trauma in a motor vehicle accident. About 80-85 percent of patients die before they arrive at the emergency department. Of those that survive to arrive at the hospital, about 70-90 percent will survive the repair of their injury. This leads to an overall survival rate of about 10-18 percent.
Patients Usually Have Other Injuries
Most patients who die of their injuries have many other injuries besides their blunt aortic injury. Mortality depends on the other injuries as well as the severity of disruption of the aortic wall. The management of these patients without surgery (who have minimal injuries) and delayed treatment in the operating room for those individuals who meet certain criteria, as well as the use of endovascular repair rather than open repair, have contributed to a lessened mortality rate in many cases.
The death rate is higher in those who have serious aortic injury who can’t be managed with surgery. One study showed that there was a mortality rate of 46 percent for patients who were not repaired compared to 9-19 percent in patients who had their aortas repaired by either means.
The incidence of blunt thoracic trauma is between 1-2 percent among those patients who sustained blunt thoracic trauma to the chest. Aortic injury is a major cause of immediate death after a motor vehicle crash. Only about 20 percent of patients survive to be able to be treated in a hospital or emergency department.
The routine evaluation of a blunt chest trauma injury includes a plain chest x-ray followed by a CT scan if the patient is stable and a blunt aortic injury is suspected. A transesophageal echocardiogram can also be done in the emergency department.
Patients need two large bore peripheral IVs for fluids and resuscitation medications. For those who have a blood pressure greater than 100 mm Hg, medications to reduce blood pressure should be given. The goal is to keep the heart rate less than 100 beats per minute and a systolic blood pressure of around 90-100 beats per minute.
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