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.