Abstract WP488: Imaging Correlates of Vascular Cognitive Impairment After Recent Ischemia in Intracranial Atherosclerosis: Evidence From SAMMPRIS

Abstract

Background: More than 50% of individuals with recently symptomatic intracranial atherosclerotic disease (ICAD) manifest cognitive dysfunction. The imaging correlates of such cognitive impairment due to large vessel disease remain largely unknown. We examined the degree of cognitive dysfunction associated with detailed quantification of MRI DWI and FLAIR lesions at baseline in the SAMMPRIS trial. Methods: Central, blinded, adjudication of baseline MRI included measurement of DWI and FLAIR lesions and corresponding volumes. Cognitive function was assayed with the Montreal Cognitive Assessment (MoCA) score (0-30). Statistical analyses were used to describe MRI lesion characteristics and the correlation with baseline MoCA score. Results: At enrollment in SAMMPRIS, baseline DWI was available in 309/451 (69%) subjects, with FLAIR in 293/451 (65%). Baseline MoCA was median 25.0 (10-30). Chronic ischemic lesion burden on FLAIR was median 2.7 cc (0-87.0), with greater extent in those older than 60 years (p=0.03) and those on anti-thrombotics (p=0.01). DWI lesion volume (median 1.45 cc, range 0-71.84) was associated with NIHSS score (p<0.01), antithrombotic use (p=0.01) and time from qualifying event to enrollment (p=0.05). The number of DWI lesions (median 9, range 1-69) correlated (r=0.63, p<0.01) with total volume of acute infarction and was associated with more than 7 days from qualifying event (15.3 vs. 10.7, p<0.01). Chronic FLAIR lesion burden was associated with worse cognitive function or lower MoCA (r=-0.18, p=0.01) at baseline. Importantly, the volume or number of acute DWI lesions was unrelated to MoCA. Conclusions: Cognitive impairment associated with recently symptomatic intracranial atherosclerosis reflects the underlying burden of chronic, not acute, ischemia. Routine MRI, including FLAIR may inform future studies of vascular cognitive impairment in large vessel disease.