There is no data about prevalence of intracranial stenosis (IS) in Northern Europe. This study aimed to investigate the prevalence of symptomatic and asymptomatic IS in a Norwegian, community-based ischemic stroke population.
In a prospective study, all ischemic stroke or transient ischemic attack (TIA) patients were screened for IS by transcranial color-coded sonography, magnetic resonance angiography, and/or computed tomography angiography. Patients with IS and any cardiac arrhythmia or other possible causes of IS than atherosclerosis were excluded. IS was defined as symptomatic if the infarct/symptoms were related to the territory of the stenotic artery. Risk factors for cerebrovascular disease were registered on admission.
During an 18-month study period, 607 patients had an ischemic stroke or a TIA. Out of 69 patients with IS (11.4%), 7 patients were excluded because having atrial fibrillation, and IS of possible atherosclerotic etiology was therefore diagnosed in 62 patients (10.2%). IS was symptomatic in 45 patients (7.4%). Diabetes mellitus was the only risk factor significantly associated with symptomatic IS (odds ratio 2.39, 95% confidence interval [CI] 1.03-5.54, P=.04).
IS occurs in approximately 10% and is symptomatic in about 7% of a Norwegian ischemic stroke/TIA population. Diabetes mellitus appears to be the major risk factor for IS.