Stroke patterns in unilateral atherothrombotic occlusion of the internal carotid artery.

BACKGROUND AND PURPOSE: Stroke patterns in patients with occlusion of the internal carotid artery (ICA) and no potential cardiac cause of stroke remain unknown. The aim of our study was to determine the pattern of stroke in patients with an occlusion of the ICA of presumed atherosclerotic origin.

METHODS: Of 873 consecutive patients admitted for an acute ischemic event during a 49-month period, 40 (29 men and 11 women; mean age, 63 years) had a unilateral occlusion of the ICA of presumed atherosclerotic origin and no other potential cause of stroke. They underwent two computed tomographic scans, Doppler ultrasonography, and B-mode echotomography of the cervical arteries or angiography and echocardiography. We compared stroke patterns between both hemispheres.

RESULTS: We found ipsilateral infarcts in 32 patients (80%; 99% confidence interval [CI], 64% to 96%) and contralateral infarcts in 12 patients (30%; 99% CI, 11% to 49%). Infarcts ipsilateral to the ICA occlusion were more likely to be cortical (odds ratio, 9.33; 99% CI, 2.4 to 36.35) or subcortical infarcts 15 mm or greater (odds ratio, 16.71; 99% CI, 1.05 to 267.3). The prevalence of subcortical infarcts less than 15 mm did not differ between hemispheres.

CONCLUSIONS: Symptomatic infarcts related to an ICA occlusion are more likely to be cortical or large subcortical infarcts. Small subcortical infarcts have the same prevalence in both hemispheres and therefore may be coincidental.