Lack of relation between severity of stroke and severity of extracranial internal carotid artery lesions in Taiwanese first-ever ischemic stroke patients

Background and Purpose. The authors attempt to determine whether hemodynamically significant extracranial internal carotid artery (ICA) lesions correlate with the severity of first-ever hemispheric ischemic stroke. Methods. Carotid duplex was used to evaluate carotid arteries. The National Institutes of Health Stroke Scale was used to describe the severity of the stroke and was stratified as follows: 1-6=mild, 7-15=moderate, >15=severe. Duplex findings were categorized according to velocity criteria into <50% stenosis if ICA peak systolic velocity (PSV) (cm/s) <140 and >50% stenosis if ICA PSV >140 or ratio of ICA and common carotid artery in PSV >2. No detectable flow at ICA was considered occlusion. Stroke subtype was classified according to TOAST criteria. Results. Two hundred nineteen consecutive patients were enrolled, including 127 with mild, 65 with moderate, and 27 with severe stroke. The prevalence of ICA stenosis >50% in each group was 3.6%, 1.4%, 0.9%, respectively. Two patients in the severe group had total ICA occlusion. The overall prevalence of significant ICA lesions was 6.8%. Conclusions. There is no positive correlation of stroke severity with the severity of duplex findings, which may be due to low prevalence of significant ICA lesions or other stroke mechanisms. Most of the patients had mild stroke, and the majority had ICA stenosis <50%. Small-vessel occlusion tended to have mild severity of stroke. Intracranial artery lesions or other factors causing stroke in Taiwanese should be investigated. Given the low incidence of significant extracranial carotid disease in symptomatic Taiwanese stroke patients, routine screening of symptomatic Taiwanese for extracranial carotid artery disease does not provide enough information to determine stroke mechanism, and transcranial Doppler should be added to the screening tests.