Abstract WP139: Impact of Intracranial Atherosclerosis Burden on Vasospasm Risk and Outcomes in Aneurysmal Subarachnoid Hemorrhage

Abstract

Background: Cerebral vasospasm is a well-known complication after aneurysmal subarachnoid hemorrhage (aSAH) and occurs more commonly in younger patients. We hypothesized that intracranial atherosclerosis, which is seen predominantly in older patients, affects vasospasm risk in aSAH. We sought to determine association between intracranial atherosclerosis burden with vasospasm and outcomes in aSAH. Design/Methods: We performed a retrospective study of a prospectively collected cohort of consecutive patients with aSAH admitted to a Comprehensive Stroke Center between July 2016 and April 2023. Intracranial atherosclerosis burden was quantified by using modified Woodcock (MW) score on CT angiograms measured by trained assessors. Vasospasm was defined based on transcranial Doppler (TCD) criteria. Worse outcome was defined as 3-month modified Rankin Scale 4-6. Univariable and multivariable logistic regression were used to test the association of predictors with outcomes. Results: We reviewed 302 cases of aSAH (mean age 56.8 years [SD 13.3], 65% female and 70% white). Cerebral vasospasm was reported in 46% of patients and was more common in younger patients (OR 0.91 for each year increase, 95% CI 0.89-0.94; p<0.001). MW scores were measured with excellent intra-rater and inter-rater reliability (Cohen’s kappa coefficient 0.9 and 0.83 respectively) ranging from 0 to 3 (median 0, IQR 0-1) with higher scores in older patients (beta coefficient 0.019, 95% CI 0.009-0.028; p<0.001). Higher MW calcification score was associated with lower risk of vasospasm (odds ratio 0.52 per point increase, 95% CI 0.36-0.78; p=0.001). There was an inverse correlation between MW scores and severity of vasospasm (beta coefficient -0.29, 95% CI -0.48, -0.1; p=0.003). However, MW score was not independently associated with worse functional outcome (p=0.62) when adjusted for age, Hunt and Hess grades, modified Fisher scores. Conclusions: Intracranial atherosclerosis is a potential mechanism for lower vasospasm rate in older SAH patients, however, it may not impact functional outcome. This may suggest intracranial atherosclerosis may affect TCD velocities without any clinical correlation. Larger prospective studies are needed to confirm our findings.