Does the angiographic appearance of a carotid stenosis predict the risk of stroke independently of the degree of stenosis?

We aimed to determine whether the angiographic characteristics of recently symptomatic carotid stenosis predict risk of subsequent ischaemic stroke independently of the degree of stenosis. First, two observers compared the angiographic characteristics of patients who subsequently suffered a carotid distribution ischaemic stroke ipsilateral to the stenosis (n = 50) with those of stroke-free controls (n = 100) matched for the degree of stenosis of the symptomatic internal carotid artery. No significant differences were found. Secondly, seven independent observers attempted to identify the angiograms of 50 patients who subsequently suffered a stroke from those of 50 stroke-free controls matched for degree of stenosis, age and sex. None of the observers identified the stroke case more often than was expected by chance alone. We conclude that clinicians cannot differentiate between 'high risk' and 'low risk' carotid stenoses on the basis of angiographic characteristics other than the degree of stenosis.