Most thoracic aneurysms are asymptomatic (eFigure 12–13). 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.