Retrograde Internal Carotid Artery Systolic Flow and a Patent External Carotid Artery Diagnosed by Duplex Scanning in a Patient with Common Carotid Artery Occlusion and Ipsilateral Subclavian Steal

Abstract

Occlusion of the common carotid artery (CCA) has been reported to occur in as high as 3 to 20% of patients with symptomatic extracranial cerebrovascular disease, although a more recent report estimates this to be 2%.2 Successful extracranial cerebrovascular revascularization can be accomplished only if a patent internal carotid artery or external carotid artery is present.In patients with CCA occlusion, conventional angiographic techniques have been able to predict internal or external carotid artery patency in only 26% of patients found to have either patent at the time of surgical exploration.2 Therefore, exploration of the carotid bifurcation has been recommended in symptomatic patients despite angiographic nonvisualization of its branches.2,3 Other modalities are needed to document internal and/ or external carotid artery patency in patients with common carotid artery occlusion. Although