CT Quantification of Intraventricular Hemorrhage Volume in Poor-Grade Aneurysmal Subarachnoid Hemorrhage: Impact on Mortality and Long-Term Disability

Background: Aneurysmal subarachnoid hemorrhage (aSAH) is a life-threatening condition with high morbidity and mortality, particularly in poor-grade patients (World Federation of Neurosurgical Societies grades IV-V). Intraventricular hemorrhage (IVH) is associated with worse outcomes, but its predictive value and interaction with demographic and clinical factors remain unclear. Purpose: To evaluate the prognostic value of IVH volume (IVHV) quantified on admission computed tomography (CT) in association with mortality and long-term disability, as well as its interaction with demographic and clinical variables in patients with poor-grade aSAH. Methods: We retrospectively analyzed all consecutive patients with poor-grade aSAH and IVH that were admitted to nine Italian tertiary centers between 1 January 2015 and 31 May 2023. Bivariate and multivariable analyses were performed to identify factors associated with mortality and disability (modified Rankin Scale [mRS]). Global intracranial hemorrhage volume (GHV) as well as the volumes of ICH (ICHV), IVH (IVHV), and SAH (SAHV) were calculated by means of analytical software in a semiautomated setting. We employed an explainable machine learning approach to examine the interplay between hemorrhage volume distribution, demographic and clinical variables to define prognostic thresholds, and to develop a decision tree model. Results: Among 326 patients with IVH (median age 61 years [IQR: 53-70], 65.6% male), IVHV was the strongest factor independently associated with mortality and disability. An IVHV threshold of 8 mL optimized sensitivity and specificity for the outcome. Combining IVHV with age and ICHV further improved prognostic thresholds in the studied population; specificity was 92% for mortality and 71% sensitivity for disability. Adding IVHV to the SAFIRE scale significantly improved its predictive power (De Long p .008). Conclusions: IVHV is a key factor associated with mortality and disability in poor-grade aSAH with intraventricular involvement. Quantifying hemorrhage volume on admission CT is a valuable tool for improving outcome stratification and guiding clinical decision-making.