Thoracic aortic aneurysm

DEFINITION

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 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.

CAUSES

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. Younger people with an ascending aortic aneurysm 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, other related disorders, such as Ehlers-Danlos and Loeys-Dietz syndromes, can contribute to a thoracic 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 your 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 leaflets 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.

Aortic dissection and aortic aneurysm

Aortic emergencies

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).
Aortic dissection is a life-threatening emergency. It’s important to treat an aortic aneurysm before dissection occurs. If dissection occurs, people can still be treated with surgery and treatments, but they will have a higher risk of complications.

SYMPTOMS

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
• Hoarseness
• Cough
• Shortness of breath

Thoracic aortic aneurysm

Aneurysms can develop anywhere along the aorta, which runs from your heart through your abdomen. When they occur in the upper part of the aorta, 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 has occurred. 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 exams to screen for aortic aneurysm.