Thoracic aortic aneurysm

Medical quality assurance by Dr. Albrecht Nonnenmacher, MD at April 30, 2016
StartDiseasesThoracic aortic aneurysm

Thoracic aortic aneurysm or TAA is a rare, but serious condition in which a section of the aorta wall weakens, potentially leading to tearing that can result in harmful or fatal internal bleeding. Affecting less than a fraction of one percent of the population, they can be the result of genetics, lifestyle, previous injury, or another preexisting medical condition.

Contents

Definition & Facts

A type of aortic aneurysm, thoracic aortic aneurysm occurs when part of the wall of the aorta, the largest artery in the body and its primary blood vessel, weakens. This causes that section of the aorta to widen or balloon out. The weaker this part of the aorta wall gets, the greater the risk of it rupturing, leading to internal bleeding and eventually death.

Symptoms & Complaints

Usually, TAAs develop over time and expand slowly. Symptoms may be imperceptible or mistaken for other ailments. Thus, it can be difficult to detect them until they rupture, causing blood to leak out along the wall of the aorta.

Because consistent symptoms are rare or shared with other maladies, TAAs are discovered while the patient is being tested or treated for some other complaint. Some TAA patients complain of a sharp, tearing pain, especially between the shoulder blades; this is rare, but can occur if the aneurysm is large, developing quickly, or about to tear.

If the aneurysm balloons up to a great enough size, it can put pressure on or obstruct other organs, such as the lungs and airway, as it grows. This can cause shortness of breath, difficulty swallowing, high-pitched breathing, or visible lumps in the neck; these symptoms, too, are rare. Other symptoms include rapid heart rate, nausea, or vomiting, clammy skin, and a sense of dread.

Causes

Thoracic aortic aneurysms are most commonly caused by arteriosclerosis, or a hardening of the arteries. This condition is most common in smokers and people with high blood pressure or high cholesterol. Risk of an aneurysm can also increase with age or following injuries sustained during a fall or motor vehicle accident.

Certain types of TAAs are most commonly associated with atherosclerosis, a type of arteriosclerosis. This is usually seen in men over the age of 55, especially those who have a history of atherosclerosis in their families. 20% of cases occur in families in which there is a history of thoracic aortic aneurysms. There are also several diseases which seem to be associated with TAAs. These include, but are not limited to:

Diagnosis & Tests

Diagnosis of a thoracic aortic aneurysm can be difficult, as symptoms develop slowly and are easily mistaken for other complaints. They are frequently diagnosed incidentally, while being tested for another complaint.

Aneurysms may show up in chest X-rays, CT scans, or MRIs. Echocardiograms and TEEs can also reveal tears in the wall of the aorta; where the former uses sound waves to build an image of the organs in question, a TEE involves inserting a probe with a transducer down the patient's throat. This allows for a closer look at any potential weakening or tears in the aorta wall.

An arteriogram or angiogram, in which a contrast dye is injected into an artery, can also be conducted to assess the condition of blood vessels and search for both tears and arterial conditions that could indicate the likelihood of an aneurysm.

Treatment & Therapy

Treatment is not necessary for all aneurysms. If a weakening or ballooning of the artery wall is caught early enough, it may only require regular medical check-ups. In these cases, a patient may be asked to visit their doctor once or twice a year for an MRI to monitor the size and severity of the aneurysm.

Medication may also be prescribed to combat high blood pressure or cholesterol, and lifestyle changes such as quitting smoking, or altering one's diet may be recommended. If the aneurysm is large, or if the patient is symptomatic, surgery may be performed. A typical TAA surgery involves deploying an artificial graft inside the aorta, limiting blood flow to the aneurysm.

Risks of this surgery include bleeding, heart attack, irregular heartbeat, paralysis, stroke, graft infection, and kidney damage. This type of surgery may also affect the blood vessels leading to the legs, which may require a second surgery to fix. The success of the surgery depends largely on the patient's condition overall, taking into account other issues such as blood pressure and cholesterol.

Prevention & Prophylaxis

Although there is no definite way to prevent a thoracic aortic aneurysm from occurring, the likelihood of suffering one is extremely rare. Risk of thoracic aortic aneurysms can run in the family, but it is possible to make lifestyle changes both to lessen the likelihood of occurrence and to remain healthy if an aneurysm already exists.

Quitting smoking and making efforts to maintain healthy blood pressure and cholesterol levels can help to reduce potential aneurysms. People for whom TAAs or related diseases run in the family may benefit from regular medical screenings, even if they are not yet showing symptoms.