Thoracic Aortic Aneurysm and Aortic Dissection

What is a thoracic aortic aneurysm?

Location of Aortas and Arteries in the Body

The aorta is the largest blood vessel in the body. It delivers oxygenated blood from the heart to the rest of the body. An aortic aneurysm is a bulging, weakened area in the wall of the aorta. Over time, the blood vessel balloons and is at risk for bursting (rupture) or separating (dissection). This can cause life threatening bleeding and potentially death. 

Illustration of thoracic aortic aneurysm"Thoracic" refers to the part of the aorta that runs through the chest (thoracic aortic aneurysm). Aneurysms occur more often in the portion of the aorta that runs through the abdomen (abdominal aortic aneurysm). 

Once formed, an aneurysm will gradually increase in size and get progressively weaker. Treatment for a thoracic aneurysm may include surgical repair or removal of the aneurysm, or inserting a metal mesh coil (stent) to support the blood vessel and prevent rupture.

What causes a thoracic aortic aneurysm to form?

Different disease processes can cause thoracic aortic aneurysms including:

  • Degenerative disease that causes breakdown of the tissue of the aortic wall

  • Genetic disorders

  • Family history

  • Atherosclerosis

  • Infection (rare)

  • Inflammation of the arteries (vasculitis)

What are the symptoms of a thoracic aortic aneurysm?

Thoracic aortic aneurysms may not cause symptoms. When symptoms do occur, they may be related to the location, size, and how fast the aneurysm is growing. 

Sudden, severe pain associated with a thoracic aneurysm may be a sign of a life-threatening medical emergency.

Symptoms of a thoracic aneurysm may include:

  • Pain in the jaw, neck, or upper back

  • Pain in the chest or back

  • Wheezing, coughing, or shortness of breath as a result of pressure on the trachea (windpipe)

  • Hoarseness as a result of pressure on the vocal cords

  • Trouble swallowing due to pressure on the esophagus

The symptoms of a thoracic aortic aneurysm may look like other conditions. See your doctor for a diagnosis.

How is a thoracic aortic aneurysm diagnosed?

Your doctor will do a complete medical history and physical exam. Other possible tests include:

  • Computed tomography scan (also called a CT or CAT scan). This test uses X-rays and computer technology to make horizontal, or axial, images (often called slices) of the body. A CT scan shows detailed images of any part of the body, including the bones, muscles, fat, and organs. CT scans are more detailed than standard X-rays.

  • Magnetic resonance imaging (MRI). This test uses a combination of large magnets, radiofrequencies, and a computer to produce detailed images of organs and structures within the body.

  • Echocardiogram (also called echo). This test evaluates the structure and function of the heart by using sound waves recorded on an electronic sensor that make a moving picture of the heart and heart valves, as well as the structures within the chest, such as the lungs and the area around the lungs and the chest organs.

  • Transesophageal echocardiogram (TEE). This test uses echocardiography to check for aneurysm, the condition of heart valves, or presence of a tear of the lining of the aorta. TEE is done by inserting a probe with a transducer on the end down the throat.

  • Chest X-ray. This test uses invisible electromagnetic energy beams to make images of internal tissues, bones, and organs onto film.

  • Arteriogram (angiogram). This is an X-ray image of the blood vessels that is used to assess conditions such as aneurysm, narrowing of the blood vessel, or blockages. A dye (contrast) will be injected through a thin, flexible tube placed in an artery. The dye makes the blood vessels visible on an X-ray.

What is the treatment for thoracic aortic aneurysm?

Treatment may include:

  • Monitoring with MRI or CT. These tests are done to check the size and rate of growth of the aneurysm.

  • Managing risk factors. Steps, such as quitting smoking, controlling blood sugar if you have diabetes, losing weight if overweight, and eating a healthy diet may help control the progression of the aneurysm.

  • Medicine. Used to control factors such as high cholesterol or high blood pressure.

  • Surgery.

    • Thoracic aortic aneurysm open repair. The type of surgery will depend on the location and type of aneurysm, and your overall health. For an ascending or aortic arch aneurysm, a large incision may be made through the breastbone. If an ascending aneurysm involves damage to the aortic valve of the heart, the valve may be repaired or replaced during the procedure. For a descending aneurysm, a large incision may extend from the back under the shoulder blade around the side of the rib cage to just under the breast. This lets the surgeon to see the aorta directly to repair the aneurysm.

    • Endovascular aneurysm repair (EVAR). EVAR requires only small incisions in the groin. Using X-ray guidance and specially-designed instruments, the surgeon can repair the aneurysm by inserting a metal mesh coil, called a stent-graft, inside the aorta. Not all thoracic aneurysms can be repaired by means of EVAR.

A small aneurysm or one that doesn't cause symptoms may not require surgical treatment until it reaches a certain size or is rapidly increasing in size over a short period of time. Your doctor may recommend "watchful waiting." This may include a CT scan or MRI scan every 6 months to closely monitor the aneurysm, and blood pressure medicine may be used to control high blood pressure.

Your doctor may recommend surgery if the aneurysm is causing symptoms or is large.

What is aortic dissection?

An aortic dissection starts with a tear in the inner layer of the aortic wall of the thoracic aorta. The aortic wall is made up of 3 layers of tissue. When a tear occurs in the innermost layer of the aortic wall, blood is then channeled into the wall of the aorta separating the layers of tissues. This generates a weakening in the aortic wall with a potential for rupture. Aortic dissection can be a life-threatening emergency. The most commonly reported symptom of an acute aortic dissection is severe, constant chest or upper back pain, sometimes described as "ripping" or "tearing." The pain may move from one place to another.

When a diagnosis of aortic dissection is confirmed, immediate surgery or stenting is usually done.

Illustration of aortic dissection

What causes aortic dissection?

The cause of aortic dissection is unclear. However, there are several risk factors associated with aortic dissection, such as:

  • High blood pressure

  • Connective tissue disorders, such as Marfan disease, Ehlers-Danlos syndrome, and Turner syndrome

  • Cystic medial disease (a degenerative disease of the aortic wall)

  • Aortitis (inflammation of the aorta)

  • Atherosclerosis

  • Bicuspid aortic valve (only 2 flaps in the aortic valve, rather than the normal 3)

  • Trauma

  • Coarctation of the aorta (narrowing of the aorta)

  • Excess fluid or volume in the circulation (hypervolemia)

  • Polycystic kidney disease (a genetic disorder characterized by the growth of numerous cysts filled with fluid in the kidneys)

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