Importance: Cognitive impairment appears to be common manifestation in patients with high grade intracranial stenosis. The rates of improvement in cognitive impairment and associated factors are not well known.
Objective: Identify the rates and predictors of major cognitive improvement in patients with non-disabling stroke or TIA attributed to 70%-99% stenosis of a major intracranial artery.
Methods: A post hoc analysis of patients in the Stenting and Aggressive Medical Management for Preventing Recurrent Stroke in Intracranial Stenosis (SAMMPRIS) Trial was performed. Each patient underwent cognitive assessment using the Montreal Cognitive Assessment (MoCA) prior to (within 30 day of TIA or non-disabling stroke) and at 3 months post randomization. Major cognitive improvement was defined by an increase in Montreal Cognitive Assessment score of 2 points or greater at follow up evaluation.
Results: A total of 172 (38.1%, 95% confidence interval [CI] 32.8 - 44.2) of 451 patients randomized had major improvement in cognitive assessment. The rate of major cognitive improvement was 151 (33.5% 95% CI 28.5 - 39.2) and 21 (4.7% 95% CI 3.0 - 7.0) among patients with MoCA score of <26 and ≥26 at baseline evaluation. The rates of major cognitive improvement did not differ between patients who were randomized to stent placement compared with best medical treatment (85 [49.4%] versus 87 [50.6%], relative risk [RR] 1.1, p=0.4). The rates of major cognitive improvement were significantly higher among patients aged ≥65 years (72 [41.9%] versus 55 [31.1%], relative risk [RR] 0.8, p=.03) and those with systolic BP ≥140 mm Hg at follow up visit (53 [30.8%] versus 39 (22.0%), relative risk [RR] 0.9, p=.05). There was a trend towards lower rates of major cognitive improvement in patients with HbA1C >6 at baseline assessment. No relationship between LDL cholesterol ≥70 mg/dl at baseline or follow up visit and major cognitive improvement was identified.
Conclusions: A relatively high rate of major cognitive improvement was observed in patients with high grade symptomatic intracranial stenosis within 3 months. The paradoxical relationship between greater age and higher systolic blood pressure at follow up evaluation with major cognitive improvement require further studies.