Thoracic Aortic Aneurysm

Depending on the size, cause or growth rate of the thoracic aortic aneurysm treatment may vary from watchful waiting to emergency surgery. Ideally, surgery for a thoracic aortic aneurysm should be planned in order to prevent among others its deadly complications.

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Symptoms

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Thoracic aortic aneurysms usually grow slowly and without symptoms, which makes them difficult to detect. Some aneurysms may never rupture as they start small and stay small, although many other expand over time. No one can predict how quickly an aortic aneurysm may grow.

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People with such an aneurysm may refer:

• Chest pain or tenderness

• Hoarseness

• Back pain

• Cough

• Shortness of breath

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Aortic aneurysms may be located anywhere along the aorta, from the heart through the chest and abdomen. When they are located in the chest, they are called thoracic aortic aneurysms. If they are located in the abdomen they are called abdominal aneurysms. Aneurysms can happen anywhere in the thoracic aorta, including the ascending aorta (ascending aorta aneurysm) near the heart, the aortic arch (arch aneurysm) in the curve of the thoracic aorta and the descending aorta (descending aorta aneurysm) in the lower part of the thoracic aorta.

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Causes

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Factors that can be related to an aneurysm's development include:

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Atherosclerosis. When the plaques build up on artery walls, they become more rigid, and the additional pressure make them to weak and bulge. Hypertension and high cholesterol are risk factors for hardening of the arteries. This is common in older people.

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Genetic conditions. Aortic aneurysms in young people often have a genetic origin. People with Marfan syndrome, a genetic condition that affects the connective tissue in the body, are at higher risk of a thoracic aortic aneurysm, so they are more susceptible to aneurysm. They often have distinct physical traits, including tall stature, very long arms, a deformed breastbone and eye problems.

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Besides Marfan syndrome, Ehlers-Danlos, Loeys-Dietz and Turner syndromes, and other family-related disorders can cause aortic aneurysm.

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Medical conditions. Inflammatory conditions, such as giant cell arteritis and Takayasu arteritis, may also cause thoracic aortic aneurysms.

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Aortic valve problems. Sometimes people with aortic valve problems have an increased risk of ascending aortic aneurysm. This is chiefly true for people with a bicuspid aortic valve.

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Not treated infection. An untreated infection, such as syphilis or salmonella rarely may be the reason of a thoracic aortic aneurysm.

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Risk factors

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Thoracic aortic aneurysm risk factors include:

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Age. Thoracic aortic aneurysms occur most often in people age 65 and older.

Smoking. Tobacco use is a strong risk factor an aortic aneurysm.

High blood pressure. Increased blood pressure damages the arteries, raising the risk of developing an aneurysm.

Atherosclerosis. The buildup of fat and other substances that can damage the lining of a blood vessel increases the risk of an aneurysm. There is a more 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 there is Marfan syndrome or other disorders, such as Loeys-Dietz syndrome or Ehlers-Danlos syndrome, there is a significantly higher risk of a thoracic aortic aneurysm.

Bicuspid aortic valve. Nearly 50% of those with bicuspid aortic valve may develop an aortic aneurysm.

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Complications

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Dissection and rupture of the aorta are the main complications of thoracic aortic aneurysm. The rupture can lead to life-threatening bleeding. In general, the larger the aneurysm, the greater the risk of rupture.

Symptoms that thoracic aortic aneurysm has burst include:

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• Sudden, intense and persistent chest or back pain

• Pain that extends to your back

• Shortness of breath

• Hypotension

• Loss of consciousness

• Trouble swallowing

• Signs of stroke such as partial weakness or paralysis of the body, difficulty speaking etc.

 

Blood clot risk

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Another complication of aortic aneurysms (mainly in descending thoracic aneurysm) is the risk of blood clots. Small blood clots can develop in the area of the aortic aneurysm. If a blood clot breaks loose, it can block a blood vessel elsewhere in the body, possibly causing serious complications.

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Diagnosis

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Thoracic aortic aneurysm is often found in a routine medical tests, such as a chest X-ray, CT scan, or ultrasound of the heart, sometimes ordered for a different reason.

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If doctor suspects that you have an aortic aneurysm, specialized tests that can confirm it may include:

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Chest X-ray. First suspect that someone has a thoracic aortic aneurysm may be by looking at chest X-ray images ordered to check for another condition.

Echocardiogram. This exam can diagnose the thoracic aortic aneurysms and is used as screening test for family members of those with thoracic aortic aneurysm. An echocardiogram uses sound waves to capture real-time images of your heart and the ascending aorta. Echocardiogram also shows if the heart chambers and valves work properly. Occasionally, to see more detailed the aorta, a transesophageal echocardiogram may recommend.

Thoracic computerized tomography. This test can provide doctors with clear images of aorta including the size and shape of an aneurysm. Alternatively, a thoracic CT angiogram with 3D reconstruction of the images is a very accurate test for diagnosis and detailed assessment.

Thoracic magnetic resonance imaging. This test can also provide doctors with good images of aorta including the size and shape of an aneurysm and may be an alternative to CT scans for people who need frequent monitoring, in order to reduce their exposure to radiation.

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Screening for thoracic aortic aneurysms

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Conditions that cause a thoracic aortic aneurysm may also be present in other family members. That is why doctors may recommend tests to check for thoracic aortic disorders if a first-degree relative has Marfan syndrome or another condition that could cause a thoracic aortic aneurysm. These tests may include:

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Imaging tests. Echocardiogram or CT scan or MRI. If there is an enlarged aorta or an aneurysm, there will be need for another imaging test within six months to make sure that aorta hasn't grown larger.

Genetic testing. If there is a family history of aneurysm or any other genetic condition that raises the risk of thoracic aortic aneurysm then a genetic testing should be considered.

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Treatment

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The goal of treatment is to prevent aneurysm from growing, and intervening before its dissection or rupture. The treatment options are medication, monitoring or intervention, which mainly involves surgery. The decision depends on the size, location of the aortic aneurysm and how fast it's growing.

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Medical monitoring

If thoracic aortic aneurysm is small, there will be a need for medication, monitoring with imaging, and management of other medical conditions that could enlarge the aneurysm. That means regular imaging tests to check on the size of aneurysm including echocardiogram, CT scan or magnetic resonance angiography (MRA) at least six months after the aneurysm is diagnosed, and at regular follow-up exams. The frequency of the imaging tests depends on the cause, the size, whether and how fast the aneurysm is growing.

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Medications

If there is hypertension, the patient will be necessary to receive medications in order to lower blood pressure and also reduce cholesterol levels to reduce the risk of complications. These medications could include:

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Beta blockers

Beta blockers lower your blood pressure by slowing your heart rate.

Angiotensin II receptor blockers

These medications are prescribed if beta blockers aren't enough to control the blood pressure or if there is contraindication for beta blockers.

Statins

These medications can help lower cholesterol, which can help reduce your risk of aneurysm complications.

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Smoker patients with thoracic aneurysm must quit smoking.

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Surgery

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If a thoracic aortic aneurysm is diagnosed, surgery is generally recommended if dimensions are about 5 centimeters and larger. In case of Marfan syndrome, or bicuspid aortic valve, or a family history of aortic dissection, surgery is indicated for smaller aneurysms because of the increased risk of complications.

For most of the thoracic aortic aneurysms open-chest surgery is the only choice, but in some selected cases that doctor may determine, some patients will be candidates for a less invasive repair that uses a stent, called endovascular surgery.

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Open-chest surgery

Open-chest surgery for thoracic aortic aneurysm involves replacement of the dilated aorta with a synthetic graft. This procedure requires open-chest surgery, and it will take a month or more to fully recover. In case of Marfan syndrome or other related conditions, the patient may need surgery to treat the ascending aorta, including the aortic root. In aortic root replacement, the surgeon removes a section of the aorta and sometimes also removes the aortic valve. The aortic valve is replaced with a mechanical or biological valve. Alternatively, valve-sparing aortic root repair is an excellent option to replace the enlarged section of the aorta with a graft, while preserving the native aortic valve.

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Endovascular surgery

Doctors attach a synthetic graft to the end of a catheter that's inserted through an artery of the leg and threaded up into the aorta. The graft — a woven tube covered by a metal mesh support — is placed at the site of the aneurysm and fastened in place with small hooks or pins. The graft reinforces the weakened section of the aorta to prevent rupture of the aneurysm.

Recovery time is generally faster with this procedure than with open-chest surgery, but endovascular surgery can't be done on everyone. Discussion with the doctor is necessary in order to make the right decision whether someone is or not a candidate for this procedure. After endovascular surgery, a regular follow-up imaging scans should be done in order to ensure that the graft isn't leaking.