Identifying high-risk asymptomatic carotid stenosis

Introduction: With more intensive medical therapy, the risk of stroke in patients with asymptomatic carotid stenosis (ACS) is now below the risk of carotid endarterectomy or stenting (intervention); ∼ 90% of patients would be better with only medical therapy. It is important, therefore, to have methods to identify the ∼ 10% of patients who stand to benefit from intervention. Areas covered: We review the evidence that the risk of asymptomatic stenosis is now below the risk of intervention, and evidence for several approaches to identifying high-risk ACS: transcranial Doppler embolus detection, echolucency and neovascularity on ultrasound, ulceration on three-dimensional ultrasound, plaque composition on magnetic resonance imaging (MRI), plaque inflammation on positron emission tomography and assessment of cerebral blood flow reserve. Expert opinion: Carotid endarterectomy or stenting should be performed only in patients with ACS if they have microemboli on transcranial Doppler, three or more ulcers detected on three-dimensional ultrasound or other features of unstable plaque such as plaque echolucency on ultrasound, intraplaque hemorrhage detected on MRI, inflamed plaques detected on PET/CT or reduced cerebral blood flow reserve. Most patients with ACS (∼ 90%) would be better off with intensive medical therapy than with intervention.