Stent Placement for Severe Stenosis of the Left Common Carotid Artery with Internal-to-External Carotid Steal

We report the case of a 64-year-old male with internal carotid artery (ICA)-to-external carotid artery (ECA) steal due to severe stenosis of the common carotid artery (CCA). Left CCA occlusion was initially diagnosed on 3-dimensional time-of-flight magnetic resonance angiography, but digital subtraction angiography revealed severe stenosis of the left CCA and retrograde flow through the left ICA feeding the left ECA. Diverted blood flow from ECA to ICA in cases with occlusion or severe stenosis of the CCA represents a well-known alternative collateral flow pattern called ECA-to-ICA steal. However, collateral flow from ICA to ECA is rarely observed and may be termed ICA-to-ECA steal. We treated CCA stenosis in our patient by carotid artery stenting (CAS) because his CCA stenosis had been gradually progressing since the initial ischaemic attack. Antegrade ICA flow subsequently recovered. To the best of our knowledge, this is the first report of ICA-to-ECA steal normalised by the treatment of CCA stenosis using CAS.