Association of intracranial atherosclerotic stenosis with 1-year cognitive impairment after acute ischemic stroke or transient ischemic attack: a nationwide prospective cohort study

Background and purpose Intracranial atherosclerotic stenosis (ICAS) is common in patients with acute ischemic stroke (AIS) or transient ischemic attack (TIA), but its relationship with long-term cognitive impairment remains unclear. This study examined whether ICAS was associated with 1-year cognitive impairment after AIS/TIA independently of cerebral small vessel disease (CSVD) and extracranial carotid artery stenosis (ECAS).Methods Data were obtained from the impairment of cognition and sleep after AIS or TIA in Chinese patients (ICONS), a subgroup of the China National Stroke Registry III. Patients with AIS or TIA within 7 days of onset who had baseline vascular imaging and 12-month cognitive assessment were included. ICAS was defined as intracranial arterial stenosis ≥50%. The primary outcome was cognitive impairment at 12 months, defined as a Montreal Cognitive Assessment (MoCA) score <23. Multivariable logistic regression and domain-specific linear regression analyses were performed after adjustment for demographic characteristics, vascular risk factors, CSVD markers, ECAS, stroke severity, and baseline cognitive status.Results A total of 1261 patients were included. Patients with ICAS had a significantly higher rate of cognitive impairment at 1 year than those without ICAS. After full adjustment, ICAS remained independently associated with 1-year cognitive impairment (odds ratio 1.524, 95% confidence interval 1.068–2.176; p = 0.020). ICAS was also significantly associated with poorer recall performance (β = −0.182, 95% confidence interval −0.293 to −0.071; p = 0.001), but not with other cognitive domains.Conclusions ICAS was independently associated with an increased risk of 1-year cognitive impairment after AIS/TIA, particularly in memory performance.