The Lone Carotid: Ultrasound Findings in Rare Innominate Artery Occlusion

Abstract

A 70-year-old woman presented with bilateral asymptomatic carotid bruits. Carotid duplex ultrasound demonstrated to-and-fro right carotid artery waveforms, retrograde right vertebral artery flow, and monophasic waveforms in the right subclavian artery. This triad of findings indicates significant stenosis or occlusion of the innominate artery. Computed tomography angiography showed an occluded innominate artery, as well as an occluded left proximal vertebral artery, resulting in the left carotid artery being the only direct source of blood flow to the brain and right upper extremity via a patent Circle of Willis. Significant innominate artery blockage is an infrequent finding and, as such, publications regarding its prevalence, treatment, and natural course are scant. We report an unusual case of an innominate artery obstruction.