Bovine arch and carotid artery atherosclerosis: are they related?

Abstract

The prevalence of the "bovine" arch in the population is known (8-25%). However, its prevalence in patients with significant carotid atherosclerosis has never been investigated. Altered flow patterns or turbulence that may occur in these patients may play a causative role in the development of atherosclerotic lesions. The primary purpose of this study was to retrospectively compare the prevalence of aortic arch variants in patients with and without significant carotid artery atherosclerosis, as we hypothesize that carotid atherosclerosis may be more prevalent in patients with a bovine arch due to hemodynamic alterations. A secondary objective was to review radiologist reporting of arch anatomy.Single-center, retrospective, case-control study in which 79 patients with hemodynamically significant carotid artery atherosclerosis who underwent computed tomography angiography, magnetic resonance angiography, or unenhanced computed tomography (CT) imaging including the aortic arch were identified. These patients were then compared with 95 randomly selected controls without carotid atherosclerosis that underwent similar imaging during the same time period. Images were independently reviewed by two blinded radiologists, who assessed arch anatomy as normal, bovine, or other variant. The original radiology reports were reviewed for reporting of arch anatomy.In controls, 70% had normal arch anatomy, and 24% had a bovine arch. Among patients with significant carotid disease, these numbers were 70% and 20%, respectively. There was no statistically significant difference between incidence of arch variants in subjects with and without carotid artery atherosclerosis (P=.97). There was good interreader agreement. Among patients with aortic arch anomalies, 20% of the original radiology reports did not mention arch anatomy.In our experience, percentage of bovine arch anomalies in patients with significant carotid atherosclerosis is not significantly different from those without disease. Clinicians should be aware of the high prevalence of arch anomalies, which can impact endovascular approach and management, and radiologists should be aware of the clinical importance of reporting such variants.