What is Traumatic Aortic Injuries (Injury to the Aorta)?
In the United States, trauma is the fourth leading cause of death in adults and the main cause of death in kids and teenagers. A specific type of trauma, traumatic aortic injuries, are uncommon but dangerous emergencies that can be life-threatening if not immediately recognized and treated. These injuries typically occur due to penetrating chest wounds, sudden stopping injuries or blunt force chest trauma. Traumatic aortic injuries may range from a bruised aorta to a complete tear, also known as an aorta rupture. Initially, there may be a contained rupture which could show minor symptoms and could appear as a pseudoaneurysm. However, this won’t last long as this pseudoaneurysm could rupture, causing severe blood loss and death.
Traumatic aortic injuries often occur due to blunt trauma and pose serious challenges due to their subtle symptoms and rapid development towards lethal complications. Even though they’re not common, such injuries significantly contribute towards the complications and deaths in trauma patients, only second to traumatic brain injury. One-third of car accident deaths are a result of thoracic aortic injuries, and it’s estimated that 80% of these patients don’t make it to the hospital.
People enduring a blunt traumatic aortic injury can show a variety of symptoms in varying degrees. Around 80-85% of patients die at the scene, while another small group, around 2-5% of cases, make it to the hospital but are in unstable conditions with mortality rates between 90-98%. About 15-20% patients arrive at the hospital in a stable condition, but diagnosis usually takes between 4 to 18 hours after the injury. Even with improvements in trauma care, the hospital mortality rate within 24 hours is between 32-50%. Many of these deaths are due to other injuries as these patients often have multiple severe injuries.
Traumatic aortic injuries may resulting from penetrating trauma, like gunshot wounds or stabbings, which typically harm the abdominal aorta. Despite survival rates being slightly better compared to blunt force injuries, the overall risk of death remains high, nearing 80%.
Diagnosing and treating these injuries quickly is pivotal for patient survival. The method of repair depends on the severity of the injury, the patient’s condition, and any other injuries. Over the past two decades, endovascular treatments have become the standard method of care for these injuries. They carry less risk and result in better health and survival outcomes than open surgery.
What Causes Traumatic Aortic Injuries (Injury to the Aorta)?
A traumatic aortic injury refers to the damage or tearing of the aorta due to a penetrating or blunt force trauma.
Blunt Force Trauma
The main cause of traumatic aortic injury is blunt force trauma, which can happen abruptly and causes the heart and the aorta to quickly stop moving within the chest. Just to note, the heart and main blood vessels (like the superior vena cava, inferior vena cava, pulmonary arteries, ascending aorta, and others) can move within the chest cavity but the lower part of the aorta doesn’t.
The injury usually happens near the end of the aortic arch, also called the isthmus. This part of the aorta is right after the subclavian artery and is where the movable and fixed parts of the aorta meet. Because of how it is positioned, this part of the aorta can tear from sudden stopping, leading to different levels of wall damage. In some people, the tear could be mild while others may completely rupture their aorta. But those who survive these injuries usually have incomplete or non-circumferential tears that don’t completely penetrate the aorta, thanks to the tunica adventitia and pleura in the middle of the chest.
Blunt force traumatic aortic injuries usually come from strong impacts, most commonly from car crashes (around 81% of cases), motorcycle and airplane crashes, car hitting pedestrian accidents, serious falls of 10 feet or more, and crush injuries.
People used to think that aortic injuries were mainly from head-on vehicle crashes. But, new hospital reports show that side-impact collisions also pose significant risk for aortic injury. Other factors with high correlation to aortic injury and rupture include a sudden speed decrease of 20 mph or more, the patient being directly hit in the vehicle, and the car wall intruding into the vehicle compartment by 15 inches or more. Interestingly, the use of seatbelts or airbags doesn’t seem to affect the risk of aortic injuries.
Penetrating Trauma
Penetrating trauma happens when there’s a direct puncture or laceration of the aorta. The main causes are high-speed injuries like gunshot wounds and low-speed ones usually caused by sharp objects like knives, axes, and glass.
Injuries to the section of the aorta in the abdomen usually come from penetrating trauma, while blunt force trauma accounts for less than 1% of these types of injuries. This region of the aorta is more prone to injury because it is close to the vertebral column, leaving it vulnerable to fractures. These injuries commonly involve the sections below the kidneys (67%), above the kidneys (33%), or extend from an aortic injury in the chest (25%).
Risk Factors and Frequency for Traumatic Aortic Injuries (Injury to the Aorta)
Traumatic aortic injury is a rare condition, affecting less than 1% of all trauma patients. In the United States, it is estimated that between 7500 and 8000 such cases occur each year. Research has shown that only a small fraction of patients with chest injuries, about 0.25%, are diagnosed with a traumatic aortic injury.
Even though the rate of occurence is low, traumatic aortic injury holds the second position after traumatic brain injury in causing death in patients with blunt-force trauma. Specifically, the injury is reported in less than 1% of car accident cases, yet, it accounts for around 33% of deaths resulting from these accidents.
- Most patients with a traumatic aortic injury are men, primarily between the ages of 16 and 50.
- Approximately 70% of these injuries occur in men, and about 67% of the patients are overweight or obese.
- The average age of patients with this injury is 43 years old.
- About 71% of patients with a traumatic aortic injury are men.
- Around 40% of these patients were under the influence of alcohol at the time of the injury.
Signs and Symptoms of Traumatic Aortic Injuries (Injury to the Aorta)
Traumatic aortic injury is a challenging condition to diagnose because it doesn’t have specific signs or symptoms. To understand if someone might have this injury, doctors will usually consider how they were hurt. For example, they may look at whether the person was involved in a serious accident like a car crash. Doctors will also check if the person has a medical history of diseases that could make them more likely to have aortic issues, such as high blood pressure or connective tissue disorders.
In some cases, an initial protective response in the body can prevent the aorta (a major blood vessel) from rupturing after an injury. But, over time, blood can gather within the outer layer of the aorta, leading to discomfort. This can result in a specific type of chest pain that is felt behind the sternum (chest bone). Other symptoms like shortness of breath, cough, back pain, and hoarseness could be due to an expanding and swelling aorta. However, it’s also possible that a person might not show any symptoms at all.
During a physical check-up, the doctor might notice low blood pressure, visible injuries on the chest, a new sound in the heart, and psuedocoarctation, which is marked by high blood pressure in the upper body and low blood pressure in the lower body, often with missing pulses in the upper leg region. This can suggest damage to the aortic arch, a curved part of the aorta. Traumatic aortic injury could also be accompanied by other injuries such as brain injury, multiple broken ribs, lung bruise, heart bruise, ruptured diaphragm, damage to the spleen or liver, injury to the small bowel, internal bleeding, spine injuries, fractures, injuries to the upper extremities, and jaw or face injuries.
If there are no specific signs indicating traumatic aortic injury, detection often depends on a strong suspicion from doctors who also consider other injuries that may distract from or complicate the diagnosis. Timely identification of a traumatic aortic injury is extremely important because delay in diagnosis and treatment can result in disastrous consequences.
Testing for Traumatic Aortic Injuries (Injury to the Aorta)
If the possibility of a traumatic aortic injury is suspected, it’s important to run tests to confirm or rule it out. This is especially true following incidents like falls from a great height or high-speed car crashes. Doctors can use various types of examinations to make this diagnosis.
Chest X-rays are often the first step in diagnosing trauma patients due to their availability and speed. However, the detection rate for aortic injury is just 40%, meaning they can’t effectively identify the damage on their own. Signs of aortic injury on a chest X-ray can include a widened mediastinum (the space in the chest between the lungs), absence of the normal shadow of the aortic knob (bent section of the aorta), a build-up of fluid or blood in the left apical pleural cap (uppermost layer of the pleural cavity), left pleural effusion (build-up of fluid between the layers of tissue lining the lungs and chest), and the misalignment of the trachea or esophagus.
Computed tomography angiography (CTA) has also proven highly effective at identifying aortic injuries, making it the preferred testing method when an aortic injury is suspected after a high-speed accident. Tell-tale signs of aortic damage on a CTA scan include pseudoaneurysm formation (a false aneurysm where blood leaks from an artery into surrounding tissue), intimal flaps (separation of the inner layer of the aorta), luminal filling defects (flaws in the channel within the aorta), periaortic hematoma (blood collected around the aorta), an unusual aortic shape, and the leakage of injected contrast medium.
In cases where a CTA isn’t available or appropriate, or when results are inconclusive, angiography (also known as aortography) may be used instead. This can also help confirm a diagnosis when aortic damage is suspected but not confirmed by other tests. Similar signs to look out for in an angiograph are dissection, pseudoaneurysm, and active bleeding.
Transesophageal echocardiography (TEE) can also be performed quickly at the patient’s bedside, providing live diagnostic images of the aorta. This is especially useful for patients who are hemodynamically unstable.
A variety of other tests, like intravascular ultrasonography and magnetic resonance imaging (MRI), can also be used in certain cases. These are generally not as common as chest X-rays or CTA scans.
It’s important to accurately determine the severity of the aortic injury to optimize treatment strategies and patient outcomes. The grades of injury range from Grade I (mild) to Grade IV (severe) with higher grades indicating more severe damage and a higher need for immediate interventions.
Treatment Options for Traumatic Aortic Injuries (Injury to the Aorta)
When someone suffers from a traumatic aortic injury, there are several factors at play when deciding on treatment. These factors include the severity of the injury, the person’s overall physical stability and any concurrent injuries. Grade I injuries, which are the mildest, are often managed medically. More severe injuries, from grade II-IV, typically need surgical repair to correct the aortic injury. Deciding between immediate surgical repair or tackling more pressing injuries first can be a difficult decision.
Initial treatment usually follows the ‘ABCs of trauma’, which stands for Airway, Breathing, Circulation, Disability and Everything else. Any conditions that are life-threatening are treated immediately. Once stabilized, the patient then has the aortic injury repaired, whether by endovascular or open repair. In a few cases, it may be beneficial to delay repair which can reduce overall mortality, though this can also lead to complications and longer stays in the intensive care unit and hospital.
When someone has a traumatic aortic injury, the priority is to stabilize them and control the progress of the injury. This can involve controlling blood pressure with intravenous beta blockers like labetalol or esmolol, which reduce heart rate and lessen strain on the aortic wall. Vasodilators, which dilate the blood vessels, can also help by reducing the forces acting on the wall of the aorta.
Whether or not surgery is needed depends on several factors. If a patient is unstable, or if a scan reveals contrast leak from the blood vessels, a rapidly expanding bruise in the middle of the chest, or a penetrating aortic injury, surgery is typically required. It’s also needed for grades II-IV injuries, but grade I injuries usually heal on their own and do not require surgery. The choice between open surgery and endovascular surgery depends on the specifics of each case.
The most significant development in treating traumatic aortic injuries is the use of stent grafting, a method known as thoracic endovascular aortic repair (TEVAR). This involves inserting a graft (a type of stent) into the damaged portion of the aorta through the major blood vessels in the thighs, preventing further blood loss. This technique has improved survival rates compared to traditional open surgery. With TEVAR, the patient has lower odds of complications such as spinal cord injury, paralysis, stroke and kidney injury.
TEVAR is typically performed in a specialised operating room, with a team on hand in case a switch to open surgery is needed. An aorta scan is used to spot the injury and a suitable stent-graft is then selected and put into place. In some cases, stent placement might need to be followed by balloon angioplasty, and another angiography completion may be needed to check for any remaining leaks.
Despite the popularity and effectiveness of TEVAR and EVAR, open surgical repair is still an option in certain cases when the anatomy of the patient makes endovascular repair impossible. This more traditional method of repair involves opening up the chest, exposing the aorta, and stitching a tube graft into place. It carries higher risks and has an approximate 24% mortality rate, and a 19% chance of resulting in paralysis. Although circumstances may require open repair, further research is needed to determine the best approach in each case.
What else can Traumatic Aortic Injuries (Injury to the Aorta) be?
When trying to diagnose a suspected injury to the aorta, the large blood vessel branching off the heart, from a traumatic event, doctors consider several other conditions that could cause similar symptoms, such as:
- Aortic dissection: This is a serious condition in which there is a tear in the wall of the aorta. This can cause severe chest pain, which may or may not spread to the back.
- Acute coronary syndrome: This includes conditions like heart attacks and unstable chest pain, which can mimic the symptoms of an aortic injury. Doctors can use heart monitoring and tests for certain enzymes to tell them apart.
- Pulmonary embolism: This happens when a blood clot gets stuck in one of the pulmonary arteries in the lungs, causing sudden chest pain, breathlessness, and instability. It can be confused with an aortic injury, especially when it causes the aorta to widen. This condition is more likely in people who have recently had surgery, cannot move much, or have a history of deep vein thrombosis (blood clots in the leg).
- Thoracic spine injury: Injuries to the middle of the spine can cause severe pain in the back that can spread to the chest or shoulders. Specialized imaging tests like CT or MRI scans can help confirm this diagnosis.
- Esophageal conditions: Conditions affecting the esophagus can mimic the symptoms of an aortic injury. Esophageal spasms can cause severe chest pain. Esophageal rupture, often brought on by intense vomiting or medical procedures, can cause severe chest pain and difficulty swallowing. And, gastroesophageal reflux disease (GERD), where stomach acid frequently flows back into the tube connecting your mouth and stomach, can cause chest pain similar to that experienced with heart-related conditions.
- Anxiety or panic disorder: These psychological conditions can also cause symptoms like chest pain, palpitations, and shortness of breath.
- Musculoskeletal pain: Chest discomfort can also be caused by non-heart related conditions such as a broken rib, muscle strain or inflammation of the rib cartilage, all of which could be confused with an injury to the aorta.
- Pneumothorax: It is a condition also known as a collapsed lung, which can cause a sudden sharp pain in the chest and shortness of breath. This can be diagnosed with a chest x-ray or a CT scan.
- Pericarditis: It is an inflammation of the sac-like covering of the heart that can cause chest pain. Patients with pericarditis may have a distinctive sound when the heart beats or certain specific changes as seen on ECG.
- Pleuritis: This is the inflammation of the membrane surrounding the lungs and chest cavity. It results in a sharp chest pain that gets worse with deep breathing or coughing and it is usually associated with viral infections, pneumonia, or connective tissue diseases.
Making the correct diagnosis involves reviewing these conditions and carrying out the appropriate tests.
What to expect with Traumatic Aortic Injuries (Injury to the Aorta)
Despite advances in medical care for trauma patients, aortic injuries, which can happen due to a blunt force or piercing trauma, still often lead to poor outcomes. Where on the aorta the injury occurs, how severe it is, how quickly it’s identified and treated, whether or not the patient has any other injuries, the treatment approach, and the patient’s overall health, all play a role in their prognosis.
Tragically, about 80% of patients with a blunt aortic injury from trauma die before they even reach the hospital. Of those who do reach medical care alive, up to 100% die if their aorta has ruptured completely, and even the least severe aortic injuries adopt a mortality rate between 18% and 80%. Those who lose their lives due to traumatic aortic injury are often severely injured. The higher the severity of the injury, the higher the likelihood of dying from aortic damage.
According to a study by Demetriades et al that looked at piercing traumatic aortic injuries, the overall mortality was 80.6%, with gunshot injuries leading to death 87.5% of the time, while knife injuries led to death 64.7% of the time. The study also found that those with aortic injuries in the abdomen were three times as likely to survive than those with injuries in the chest (23.9% vs 7.7%).
Aortic injuries from blunt or piercing trauma are very serious and require immediate treatment. Piercing injuries may have better outcomes than blunt injuries if the right treatment is given quickly. Quick identification of the problem, rapid transportation to a traumatic care center, and a team of professionals like vascular surgeons, trauma surgeons, and other specialists are key to giving the patient the best chance of survival.
Possible Complications When Diagnosed with Traumatic Aortic Injuries (Injury to the Aorta)
Traumatic aortic injuries can lead to serious, even life-threatening complications if not promptly recognised and treated. There are also potential delayed issues that can occur days or weeks after the initial injury, such as the formation of a pseudoaneurysm or a late-onset aortic dissection. Regular monitoring and a high level of attention are key for spotting and managing these issues which can be:
- Aortic rupture: This can happen when the aorta, a major blood vessel, tears or bursts leading to heavy bleeding and, if not treated urgently, can cause a drop in blood pressure and death.
- Aortic dissection: A tear in the aorta’s inner layer caused by a traumatic injury can create a false cavity within the wall of the vessel. This could cause blood flow to be disturbed, potentially cutting off the supply of blood to vital organs, or it might trigger a devastating aortic rupture.
- Aortic aneurysm: A weakening of the aortic wall can lead to a bulge or dilation that could be at risk of rupturing, especially if it continues to grow or if there’s ongoing trauma to the area.
- Hemothorax: Severe aortic injury can result in bleeding into the space around the lungs, which can affect their function and cause respiratory distress unless the blood is promptly drained.
- Organ ischemia: Severe injuries to the aorta can interrupt blood flow to abdominal organs and the lower extremities, causing conditions like ischemic bowel, kidney failure, or limb ischemia.
- Spinal cord injury: Traumatic injuries to certain parts of the aorta can lead to a lack of blood flow to the spinal cord, which can result in neurological issues or even paralysis. This can be a serious complication of a traumatic aortic injury.
As with any surgical procedure, repairing a traumatic aortic injury carries risks of bleeding, infection, or damage to surrounding tissues. The use of endografts, or endovascular stent grafts, often used in repair procedures, bring their unique risks such as:
- Endoleak: This happens when blood leaks around the graft. This can increase rupture risk in the weeks or months following the procedure. The incidence of endoleak is reduced with correctly sizing the graft to the aorta.
- Migration: The graft can move from its original placement within the aorta, leading to potential leaks, misalignment, or compromise of branch vessel supply.
- Endograft limb occlusion: The graft can block the branch vessels or visceral arteries coming from the aorta, leading to reduced blood flow to affected organs.
- Infection: Though less common than with open surgery, infections can lead to sepsis and could be due to contamination during surgery, bacterial spread, or erosion of nearby structures.
- Thrombosis: Clotting in the graft or its branches can lead to sudden limb ischemia or compromised blood flow to vital organs.
- Device breaker or part degradation: The long-term endurance of endografts is still under analysis and complications can lead to leaks or device failure.
- Access site complications: These are well-documented and can cover femoral artery injury, hematoma, pseudoaneurysm formation or site infection.
Preventing Traumatic Aortic Injuries (Injury to the Aorta)
To prevent traumatic aortic injuries, it’s crucial to spread awareness about the ways in which they can be avoided. Here are a few strategies:
Road Safety Education
Safe driving practices can save lives. It’s important to respect speed limits, wear seat belts correctly, and avoid distractions like texting or taking calls while driving. Reckless driving can lead to serious injuries if a crash occurs, and everyone should be aware of this.
Workplace Safety Training
For those working in risky jobs, like construction, manufacturing, or transportation, safety training is vital. This could involve learning how to use machinery correctly, using personal protective gear, and following safety rules and guidelines.
Fall Prevention
Elderly individuals should be educated about preventing falls, which can lead to serious injuries. Some precautions could be improving home lighting, removing obstacles that could cause falls, using aids like handrails or grab bars, and doing exercises to increase strength, balance, and stability.
Violence Prevention
Raising awareness about the dangers of violence and providing resources for conflict resolution and anger management is beneficial. Individuals dealing with abuse should be encouraged to reach out for help. Community efforts that aim to reduce violence and foster peaceful resolution of conflicts should be promoted.