Abstract P392: Early Brain Injury and Soluble ST2 After Non-Traumatic Subarachnoid Hemorrhage

Intro: Early Brain Injury (EBI) after non-traumatic subarachnoid hemorrhage (SAH) is a significant mediator of neurological injury, but the injury pathways and markers are not well understood. We hypothesized that the inflammatory mediator soluble ST2 (sST2) is associated with markers of EBI. Methods: We studied two independent cohorts, including 190 SAH patients in a discovery cohort and 50 patients in a replication cohort. Clinical markers of EBI included early loss of consciousness, Glasgow Coma Scale (GCS) score at 24 hours, and neurological deterioration within the first 72 hours (defined as a decrease in GCS ≥ 2 points). Radiographic markers included bicaudate index, clinically significant hydrocephalus requiring external ventricular drainage (EVD), and global cerebral edema. Serial plasma sST2 level was measured at early (3.5 ± 1.2 days post-hemorrhage), intermediate (7.8 ± 1.3 days post-hemorrhage), and late (13 ± 2.3 days post-hemorrhage) time points in the discovery cohort and daily during post-hemorrhage days 1-9 in the replication cohort. In the discovery cohort, the relationship between EBI markers and poor functional outcome (90-day modified Rankin Scale; mRS ≥ 3) was assessed using multivariable logistic regression. The association between sST2 level and EBI markers was evaluated using repeated measures analysis. In the replication cohort, associations were examined using an analysis of response profiles. Results: Clinical and radiographic markers of EBI, except for global edema, were each associated with functional outcome in univariate analysis. Of these EBI markers, independent predictors of poor outcome included 24-hour GCS (OR=5.76, 95% CI 2.31-14.4, p<0.001) and clinically significant hydrocephalus (OR=8.74, 95% CI 2.44-31.3, p=0.001). Elevated sST2 was associated with all markers of EBI except for global edema, and independently predicted poor outcome in a multivariate model that included EBI markers. These findings were further replicated in an independent cohort. Conc: Of the potential clinical and radiographic contributors to EBI, poor 24-hour GCS and clinically significant hydrocephalus remain independent predictors of poor outcome. Furthermore, soluble sST2 level is associated with EBI and poor outcome.