Double Aortic Arch Suspected upon Transthoracic Echocardiography and Diagnosed upon Computed Tomography

A 21-year-old man without prior respiratory or vocal ailments was referred to our hospital for pneumonia. Neither his personal nor his family medical history indicated noteworthy disease. Chest radiography showed enlargement of the upper mediastinum (Fig. 1). Transthoracic echocardiography (TTE), transesophageal echocardiography (TEE), and computed tomography (CT) were planned to resolve a differential diagnosis of aortic aneurysm or dissection. On TTE, the apical and the parasternal long- and short-axis views showed the aorta to be within normal range, but the suprasternal view showed 2 descending aortic flow patterns, separated by a membrane. This finding (Figs. 2 and 3) suggested an aortic anomaly—probably a double aortic arch. The patient could not tolerate TEE. Multidetector CT was used. It revealed a double aortic arch, each arch with its own vascular structure (Figs. 4 and 5). Because the patient was asymptomatic, he was discharged from the hospital with instructions for periodic follow-up.

Fig. 1 Chest radiograph shows upper mediastinal enlargement.

Fig. 2 Two-dimensional trans-thoracic echocardiography of the double aortic arch: Doppler-flow recordings, (A) and (C); 2-dimen-sional suprasternal view (B). Arrows show direction of flow. L = left; R = right

Fig. 3 Color-flow Doppler transthoracic echocardiography (suprasternal view) shows the double aortic arch, with 2 descending aortic flow patterns, and the direction of flow (arrows).

Fig. 4 Three-dimensional computed tomographic reconstruction (posterior view) shows the double aortic arch and the surrounding vasculature.

Desc Ao = descending aorta; L arch = left aortic arch; LCC = left common carotid artery; L Pa = left pulmonary artery; LS art = left subclavian artery; R arch = right aortic arch; RPa = right pulmonary artery

Fig. 5 Three-dimensional computed tomographic reconstruction (superior view) shows the double aortic arch and the surrounding vasculature.

Desc Ao = descending aorta; L arch = left aortic arch; LCC = left common carotid artery; L Pa = left pulmonary artery; LS art = left subclavian artery; Main P Art = main pulmonary artery; R arch = right aortic arch; RCC = right common carotid artery; RS art = right subclavian artery

Aortic arch anomalies that form a vascular ring can compress the trachea and esophagus.¹ Because our patient had no symptoms that we attributed to compression, such as vocal changes or respiratory stridor, we suspected a more extraordinary finding.

The diagnosis of double aortic arch can be reached by use of echocardiography; however, the diagnosis may be missed due to a lack of experience with this uncommon anomaly. This case reminds us that aortic arch anomalies can be suspected non-invasively upon TTE and confirmed upon use of multidetector CT.