Thoracic aortic aneurysm
A thoracic aortic aneurysm is a weakened area in the body’s main artery (aorta) in the chest. When the aortic wall is weak, the artery may widen. When the vessel is significantly widened, it’s called an aneurysm.
A thoracic aortic aneurysm is also called a thoracic aneurysm.
What causes a thoracic aortic aneurysm to form?
- Degenerative disease that causes breakdown of the tissue of the aortic wall
- Genetic disorders
- Family history
- Infection (rare)
- Inflammation of the arteries (vasculitis)
Symptoms and Signs
Most thoracic aneurysms are asymptomatic. When symptoms occur, they depend largely on the size and the position of the aneurysm and its rate of growth. Substernal back or neck pain may occur. Pressure on the trachea, esophagus, or superior vena cava can result in the following symptoms and signs: dyspnea, stridor, or brassy cough; dysphagia; and edema in the neck and arms as well as distended neck veins. Stretching of the left recurrent laryngeal nerve causes hoarseness. With aneurysms of the ascending aorta, aortic regurgitation may be present due to dilation of the aortic valve annulus. Rupture of a thoracic aneurysm is catastrophic because bleeding is rarely contained, allowing no time for emergent repair.
The aneurysm may be diagnosed on chest radiograph by the calcified outline of the dilated aorta. CT scanning is the modality of choice to demonstrate the anatomy and size of the aneurysm and to exclude lesions that can mimic aneurysms, such as neoplasms or substernal goiter. MRI can also be useful. Cardiac catheterization and echocardiography may be required to describe the relationship of the coronary vessels to an aneurysm of the ascending aorta.
Indications for repair depend on the location of dilation, rate of growth, associated symptoms, and overall condition of the patient. Aneurysms measuring 6 cm or larger may be considered for repair. Aneurysms of the descending thoracic aorta are treated routinely by endovascular grafting. Repair of arch aneurysms should be undertaken only if there is a skilled surgical team with an acceptable record of outcomes for these complex procedures.
The availability of thoracic aortic endograft technique for descending thoracic aneurysms or complex branched endovascular reconstructions for aneurysms involving the arch or visceral aorta (custom-made grafts with branches to the vessels involved in the aneurysm) does not change the indications for aneurysm repair. Aneurysms that involve the proximal aortic arch or ascending aorta represent particularly challenging problems.
Open surgery is usually required; however, it carries substantial risk of morbidity (including stroke, diffuse neurologic injury, and intellectual impairment) because interruption of arch blood flow is required.