Volume of Aneurysmal Subarachnoid Hemorrhage and Cognitive Outcomes.

Background: The modified Fisher score is commonly used after aneurysmal subarachnoid hemorrhage (aSAH) to estimate hemorrhage burden and support early prognostication, although its accuracy in predicting cognitive outcomes remains limited. This study compares the predictive value of the subjective asessment of aSAH volume through the modified Fisher score with an objetive volumetric quantification in prognosticating cognitive outcomes.

Methods: This retrospective observational study included patients with aSAH between 2009 and 2024 and good functional recovery (modified Rankin score ≤ 2) at least 6 months after aSAH. Cognitive outcomes were assessed using Montreal Cognitive Assessment scores normalized to population data, with poor outcomes defined as Montreal Cognitive Assessment scores < 25th percentile for normative data. A semiautomated method was used to quantify hemorrhage volume from presentation on computed tomography scans. Logistic regression, receiver operating characteristic curves, and mediation analyses were conducted to evaluate the potential relationship between aSAH volume, clinical variables, and cognitive outcomes.

Results: A total of 142 patients with aSAH were included in the study, with 30% of patients (43/142) experiencing poor cognitive outcomes. The objective quantification of hemorrhage volume demonstrated a superior predictive performance compared with the modified Fisher score in determining poor cognitive outcomes (area under the curve 0.75 vs. 0.66, p = 0.037). An aSAH volume cutoff of 24 mL yielded a sensitivity of 72% and a specificity of 60% in predicting poor cognitive outcomes. Mediation analysis revealed partial mediation by vasospasm in the relationship between hemorrhage volume and poor cognitive outcomes.

Conclusions: There is a high rate of cognitive impairment among survivors with aSAH with good functional recovery. Volume quantification outperformed the modified Fisher score in predicting cognitive outcomes after aSAH. aSAH volumes more than 24 mL are linked to worse outcomes, with vasospasm contributing to this association.