Prognostic Model for Chronic Shunt-Dependent Hydrocephalus After Aneurysmal Subarachnoid Hemorrhage

Abstract

Patients with aneurysmal subarachnoid hemorrhage (aSAH) are at risk of the development of chronic shunt-dependent hydrocephalus. However, identification of shunt-dependent patients remains challenging. We sought to develop a prognostic model to identify patients with aSAH at risk of chronic shunt-dependent hydrocephalus. In addition to the well-known prognostic variables, blood clearance in the cerebrospinal fluid (CSF) spaces was considered. We retrospectively analyzed the data from 227 patients treated at our institution from January 2012 to January 2016. The outcome was ventriculoperitoneal shunt placement within 30 days after aSAH. The candidate prognostic variables were patient age, World Federation of Neurological Surgeons grade and Fisher grade, external ventricular drainage, ventricular and intracerebral hemorrhage, and interval to blood clearance in the peripheral/basal CSF spaces. Adjustment for multiple testing was performed. Multivariable logistic regression analysis was used for model development. Bootstrapping was applied for internal validation. The model performance measures included indexes for explained variance (R2), calibration (graphic plot, Hosmer-Lemeshow test), and discrimination (c-statistic). Of the 227 patients, 90 (39.6%) required a ventriculoperitoneal shunt. The constructed prognostic model combined external ventricular drainage placement, the presence of ventricular blood, and the duration of blood clearance in the basal cisterns. The model performance was promising, with an R2 of 33% (20% after bootstrapping), the calibration plot was adequate, the Hosmer-Lemeshow test result was not significant, and the c-statistic was 0.85 (0.84 as assessed after bootstrapping) indicating a good discriminating prognostic model. Our prognostic model could help identify patients requiring permanent CSF diversion after aSAH, although additional modification and external validation are needed. Interventions aimed at accelerating the clearance of blood in the basal cisterns might have the potential to prevent the development of chronic hydrocephalus after aSAH.