Incidence of aortic arch anomalies in patients with thoracic aortic dissections.

Background And Aim Of Study: Traditionally aortic arch anomalies have been viewed as a "normal" and clinically insignificant; therefore, they are often overlooked by radiologists and go unreported. Arch anomalies have been reported to occur in 7% to 15% of patients without thoracic aortic aneurysm or dissection. This study aims to define the incidence of aortic arch anomalies in patients with a thoracic aortic dissection (TAD).

Methods: We retrospectively reviewed all patients from 2006 to 2010 with a TAD admitted to a single institution. Thoracic computed tomography images of 176 patients with dissected thoracic aortas and 179 consecutive, unselected age-matched patients without dissection as controls were reviewed to determine the incidence of bovine arch and other arch anomalies. Statistical analysis of demographic data and clinical outcomes was performed to evaluate significant differences between the groups.

Results: Arch anomalies occurred in 34% of patients with TAD compared to controls (19%, p = 0.0017). The most common variant was a common origin of the innominate and left common carotid arteries ("bovine" arch) found in 31% of dissection patients compared to 15% in the control group (p = 0.0004). Overall arch anomalies occurred in 27% of all Type A dissections and 39% (p = 0.1409) of all Type B dissections. The association was statistically significant in patients ages 50 to 79 with TAD (36.4%, p = 0.0011) and in African Americans collectively (43.2%, p = 0.0033).

Conclusions: Aortic arch anomalies occur frequently in patients with TAD and therefore may represent a proclivity for this life threatening condition.