Subarachnoid Extension Predicts Lobar Intracerebral Hemorrhage Expansion

BACKGROUND AND PURPOSE—We investigated whether subarachnoid extension (SAHE) of intracerebral hemorrhage (ICH) is associated with hematoma expansion (HE). METHODS—Retrospective analysis of patients with primary spontaneous ICH admitted at 3 academic hospitals in Italy. The study population was divided into a development and a replication cohort. SAHE was rated on baseline noncontrast computed tomography by investigators blinded to clinical data. The main outcome of interest was HE, defined as ICH growth >33% mL and/or >6 mL. Predictors of HE were explored with multivariable logistic regression stratified by ICH location (lobar versus nonlobar). RESULTS—A total of 360 and 192 patients were included in the development and replication cohort, respectively. SAHE was identified with good interrater reliability (K=0.82), and its frequency was 27.8% in the development and 24.5% in the replication cohort. In univariate analysis, HE was more common in patients with SAHE (52.0% versus 27.3%; P