A thoracic aortic aneurysm is a weakened area in the upper part of the aorta. The aorta is the major blood vessel that feeds blood to the body.
A thoracic aortic aneurysm may also be called thoracic aneurysm and aortic dissection (TAAD) because an aneurysm can lead to a tear in the artery wall (dissection) that can cause life-threatening bleeding. Small and slow-growing thoracic aortic aneurysms may not ever rupture, but large, fast-growing aneurysms may rupture.
Depending on the cause, size and growth rate of your thoracic aortic aneurysm, treatment may vary from watchful waiting to emergency surgery. Ideally, surgery for a thoracic aortic aneurysm can be planned if necessary.
Thoracic aortic aneurysms often grow slowly and usually without symptoms, making them difficult to detect. Some aneurysms will never rupture. Many start small and stay small, although many expand over time. How quickly an aortic aneurysm may grow is difficult to predict.
As a thoracic aortic aneurysm grows, some people may notice:
- Tenderness or pain in the chest
- Back pain
- Shortness of breath
Aortic aneurysms can develop anywhere along the aorta, which runs from your heart through your chest and abdomen. When they occur in the chest, they are called thoracic aortic aneurysms. Aneurysms can occur anywhere in the thoracic aorta, including the ascending aorta near the heart, the aortic arch in the curve of the thoracic aorta and the descending aorta in the lower part of the thoracic aorta.
Aneurysms that form in the lower part of your aorta — called abdominal aortic aneurysms — are more common than thoracic aortic aneurysms. An aneurysm can also occur in between the upper and lower parts of your aorta. This type of aneurysm is called a thoracoabdominal aneurysm.
When to see a doctor
Most people with aortic aneurysms do not have symptoms unless a tear (dissection) or rupture occurs. A rupture or dissection is a medical emergency. Call 911 or your local emergency number for immediate assistance.
If an aneurysm ruptures or one or more layers of the artery wall splits (dissection), you may feel:
- Sharp, sudden pain in the upper back that radiates downward
- Pain in your chest, jaw, neck or arms
- Difficulty breathing
If you have a family history of aortic aneurysm, Marfan syndrome or other connective tissue disease, or bicuspid aortic valve, your doctor may recommend regular ultrasound or radiology testing such as computerized tomography (CT) scan or magnetic resonance imaging (MRI) exams to screen for aortic aneurysm.
Factors that can contribute to an aneurysm's development include:
- Hardening of the arteries (atherosclerosis). As plaque builds up on your artery walls, they become less flexible, and the additional pressure can cause them to weaken and bulge. High blood pressure and high cholesterol are risk factors for hardening of the arteries. This is more common in older people.
Genetic conditions. Aortic aneurysms in younger people often have a genetic cause. People who are born with Marfan syndrome, a genetic condition that affects the connective tissue in the body, are particularly at risk of a thoracic aortic aneurysm. Those with Marfan syndrome may have a weakness in the aortic wall that makes them more susceptible to aneurysm. People with Marfan syndrome often have distinct physical traits, including tall stature, very long arms, a deformed breastbone and eye problems.
Besides Marfan syndrome, Ehlers-Danlos, Loeys-Dietz and Turner syndromes, and other family-related disorders can cause an aortic aneurysm. Ehlers-Danlos syndrome causes your skin, joints and connective tissue to be fragile and makes your skin stretch easily.
- Other medical conditions. Inflammatory conditions, such as giant cell arteritis and Takayasu arteritis, may cause thoracic aortic aneurysms.
- Problems with your heart's aortic valve. Sometimes people who have problems with the valve that blood flows through as it leaves the heart (aortic valve) have an increased risk of thoracic aortic aneurysm. This is mainly true for people who were born with a bicuspid aortic valve, meaning the aortic valve has only two cusps instead of three.
- Untreated infection. Though it is a rare cause of thoracic aortic aneurysm, it's possible to develop this condition if you've had an untreated infection, such as syphilis or salmonella.
- Traumatic injury. Rarely, some people who are injured in falls or motor vehicle crashes develop thoracic aortic aneurysms.
An aortic aneurysm is different from an aortic dissection. Aortic dissection can occur in the same place many aneurysms occur. In aortic dissection, a tear occurs in the wall of the aorta. This causes bleeding into and along the aortic wall and, in some cases, completely outside the aorta (rupture).
An acute aortic dissection is a potential life-threatening emergency, depending on where in the aorta it occurs. It's important to treat an aortic aneurysm to try to prevent dissection. If dissection occurs, people can still be treated with surgery, but they will have a higher risk of complications.
Thoracic aortic aneurysm risk factors include:
- Age. Thoracic aortic aneurysms occur most often in people age 65 and older.
- Tobacco use. Tobacco use is a strong risk factor for the development of an aortic aneurysm.
- High blood pressure. Increased blood pressure damages the blood vessels in the body, raising your chances of developing an aneurysm.
- Buildup of plaques in your arteries (atherosclerosis). The buildup of fat and other substances that can damage the lining of a blood vessel (atherosclerosis) increases your risk of an aneurysm. This is a more common risk in older people.
- Family history. People who have a family history of aortic aneurysm are at increased risk of having one. Those with a family history of aneurysms tend to develop aneurysms at a younger age and are at higher risk of rupture. This is a primary risk factor in younger people.
- Marfan syndrome and related disorders. If you have Marfan syndrome or related disorders, such as Loeys-Dietz syndrome or Ehlers-Danlos syndrome, you have a significantly higher risk of a thoracic aortic aneurysm.
- Bicuspid aortic valve. Nearly half of those who have an aortic valve with two cusps instead of three (bicuspid aortic valve) may develop an aortic aneurysm.
Tears in the wall of the aorta (dissection) and rupture of the aorta are the main complications of thoracic aortic aneurysm. A ruptured aortic aneurysm can lead to life-threatening internal bleeding. In general, the larger the aneurysm, the greater the risk of rupture.
Signs and symptoms that your thoracic aortic aneurysm has burst include:
- Sudden, intense and persistent chest or back pain
- Pain that radiates to your back
- Trouble breathing
- Low blood pressure
- Loss of consciousness
- Shortness of breath
- Trouble swallowing
- Weakness or paralysis of one side of the body, difficulty speaking, or other signs of stroke
Blood clot risk
Another complication of aortic aneurysms is the risk of blood clots. Small blood clots can develop in the area of the aortic aneurysm. If a blood clot breaks loose from the inside wall of an aneurysm, it can block a blood vessel elsewhere in your body, possibly causing serious complications.