Variants of the Aortic Arch in Adult General Population and their Association with Thoracic Aortic Aneurysm Disease

Abstract

Background. Query a single institution computed tomography (CT) database to assess the prevalence of aortic arch anomalies in general adult population and their potential association with thoracic aortopathies. Methods. CT chest scan reports of patients aged 50-85 years old performed for any indication at a single health system between 2013 and 2016 were included in the analysis. Characteristics of patients with and without aortic arch anomalies were compared by t-test and Fisher exact tests. Logistic regression analysis was performed to assess for independent risk factors of thoracic aortic aneurysm. Results. Of 21,336 CT scans, 603 (2.8%) described arch anomalies. Bovine arch (n=354, 58.7%) was the most common diagnosis. Patients with arch anomalies were more likely to be female (p<0.001), non-Caucasian(p<0.001), and hypertensive (p<0.001). Prevalence of thoracic aortic aneurysm in arch anomalies group was 10.8% (n=65) compared to 4.1% (n=844) in the non-arch anomaly cohort (p<0.001). The highest prevalence of thoracic aneurysm was associated with right-sided arch combined with aberrant left subclavian configuration (33%), followed by bovine arch (13%), and aberrant right subclavian artery (8.2%). On binary logistic regression, arch anomaly (OR=2.85 [2.16-3.75]), aortic valve pathology (OR 2.93 [2.31-3.73]), male sex (OR 2.38 [2.01-2.80]), and hypertension (OR 1.47 [1.25-1.73]) were significantly associated with increased risk of thoracic aneurysm disease. Conclusions. Reported prevalence of aortic arch anomalies by CT imaging in the older adult population is ~3%, with high association of thoracic aortic aneurysm (OR=2.85) incidence in this subgroup. This may warrant a more tailored surveillance strategy for aneurysm disease in this subpopulation.