Predictors of Shunt-Dependent Hydrocephalus Following Aneurysmal Subarachnoid Hemorrhage

BACKGROUND: Shunt-dependent hydrocephalus is a common complication of aneurysmal subarachnoid hemorrhage (aSAH). There is a need to identify patients who require ventriculoperitoneal shunt (VPS) insertion so that any modifiable risk factors can be addressed early after aSAH. METHODS: Exploratory analysis was performed on 413 patients enrolled in CONSCIOUS-1, a prospective randomized controlled trial of patients with aSAH treated with clazosentan. The association between clinical and neuroimaging covariates and VPS placement was first determined by univariate analysis. Covariates with P < 0.15 on univariate analysis were then analyzed in a multivariate logistic regression model. Receiver operating characteristic curve analysis was used to define optimal predictive thresholds. The published literature was reviewed to determine the overall rate of VPS insertion after aSAH. RESULTS: Overall, 17.2% (71/413) of patients required VPS insertion. Multivariate analysis demonstrated that insertion of an external ventricular drain (odds ratio, 6.21; 95% confidence interval, 2.51-16.91) and increasing volume of cerebrospinal fluid (CSF) drainage per day (odds ratio, 1.004; 95% confidence interval, 1.000-1.009) were associated with VPS insertion. Receiver operating characteristic curve analysis revealed an optimal daily CSF output threshold of 78 mL was predictive of VPS insertion. Among 41,789 patients with aSAH from 66 published studies, the overall VPS insertion rate was 12.7%. CONCLUSIONS: The presence of an external ventricular drain and increased daily CSF output (above 78 mL/day) seems to be predictive of subsequent VPS insertion after aSAH. Although we could not identify modifiable risk factors for needing a VPS, nevertheless, these findings identify patients at greatest risk of VPS placement and inform treatment decisions as well as patient expectations.