Can simple clinical features be used to identify patients with severe carotid stenosis on Doppler ultrasound?

Objectives-Carotid endarterectomy reduces the risk of stroke in symptomatic patients with severe ipsilateral carotid stenosis. Symptomatic patients sh ould therefore undergo carotid Doppler imaging, but in some centres access to imaging is limited. It was therefore investigated whether simple clinica l features alone or in combination could be used to identify patients with severe carotid stenosis, so that they could be referred preferentially for carotid imaging. Methods-1041 patients with acute stroke, cerebral or retinal transient isch aemic attacks, and retinal strokes admitted to Western General Hospital or seen in neurovascular clinics were assessed by a stroke physician. Their ca rotid arteries were investigated using colour Doppler imaging by a consulta nt neuroradiologist. Patients with primary intracerebral haemorrhage, total anterior circulation strokes, posterior circulation strokes, or posterior circulation transient ischaemic attacks were excluded because carotid surge ry would be inappropriate. Results-726 patients were used in the analysis. Stepwise logistic regressio n showed that there were significant positive associations between severe c arotid stenosis and an ipsilateral bruit, diabetes mellitus, and previous t ransient ischaemic attacks; and a negative association with lacunar events. The strategy with the highest specificity (97%) was "any three of these fo ur features" but sensitivity was only 17%. The strategy with the highest se nsitivity (99%) was to use one or more of the four features, but specificit y was only 22%. Conclusion-None of the strategies identified all patients with severe carot id stenosis with a reasonable specificity. When access to carotid imaging i s severely Limited, simple clinical features are of some use in prioritisin g patients for imaging, but access to carotid imaging should be improved.