Effect of small-vessel disease on cognitive trajectory after atrial fibrillation-related ischaemic stroke or TIA

Post-stroke dementia is common but has heterogenous mechanisms that are not fully understood, particularly in patients with atrial fibrillation (AF)-related ischaemic stroke or TIA. We investigated the relationship between MRI small-vessel disease markers (including a composite cerebral amyloid angiopathy, CAA, score) and cognitive trajectory over 12 months. We included patients from the CROMIS-2 AF study without pre-existing cognitive impairment and with Montreal Cognitive Assessment (MoCA) data. Cognitive impairment was defined as MoCA <26. We defined "reverters" as patients with an "acute" MoCA (immediately after the index event) score <26, who then improved by 2 points at 12months. In our cohort (n=114), 12-month MoCA improved overall relative to acute performance (mean difference 1.69 points, 95% CI 1.03-2.36, p<0.00001). 12-month cognitive impairment was associated with increasing CAA score (per-point increase, adjusted OR 4.09, 95% CI 1.36-12.33, p=0.012). Of those with abnormal acute MoCA score (n=66), 59.1% (n=39) were "reverters". Non-reversion was associated with centrum semi-ovale perivascular spaces (per-grade increase, unadjusted OR 1.83, 95% CI 1.06-3.15, p=0.03), cerebral microbleeds (unadjusted OR 10.86, 95% CI 1.22-96.34, p=0.03), and (negatively) with multiple ischaemic lesions at baseline (unadjusted OR 0.11, 95% CI 0.02-0.90, p=0.04), as well as composite small-vessel disease (per-point increase, unadjusted OR 2.91, 95% CI 1.23-6.88, p=0.015) and CAA (per-point increase, unadjusted OR 6.71, 95% CI 2.10-21.50, p=0.001) scores. In AF-related acute ischaemic stroke or TIA, cerebral small-vessel disease is associated both with cognitive performance at 12months and failure to improve over this period.