Shunt-dependent hydrocephalus after aneurysmal subarachnoid hemorrhage: Predictors and long-term functional outcomes

Background: Although chronic hydrocephalus requiring shunt placement is a known sequela of aneurysmal subarachnoid hemorrhage (aSAH), its effect on long-term functional outcomes is incompletely understood. Objective: To identify predictors of shunt-dependent hydrocephalus and shunt complications after aSAH and determine the effect of shunt dependence on functional outcomes in aSAH patients. Methods: We evaluated a database of patients treated for aSAH at a single center from 2000 to 2015. Favorable and unfavorable outcomes were defined as modified Rankin Scale grades 0 to 2 and 3 to 6, respectively. We performed statistical analyses to identify variables associated with shunt-dependent hydrocephalus, unfavorable outcome, and shunt complication. Results: Of the 888 aSAH patients, 116 had shunt-dependent hydrocephalus (13%). Older age (P = .001), intraventricular hemorrhage (IVH) (P = .004), higher World Federation of Neurological Surgeons (WFNS) grade (P < .001), surgical aneurysm treatment (P = .002), and angiographic vasospasm (P=.005) were independent predictors of shunt-dependent hydrocephalus in multivariable analysis. Functional outcome was evaluable in 527 aSAH patients (mean follow-up 18.6 mo), with an unfavorable outcome rate of 17%. Shunt placement (P < .001), shunt infection (P = .041), older age (P < .001), and higher WFNS grade (P = .043) were independently associated with an unfavorable outcome in multivariable analysis. Of the shunt-dependent patients, 18% had a shunt-related complication. Higher WFNS grade (P= .011), posterior circulation aneurysm (P= .018), and angiographic vasospasm (P=.008)were independent predictors of shunt complications inmultivariable analysis. Conclusion: aSAH patients with shunt-dependent hydrocephalus have significantly poorer long-term functional outcomes. Patients with risk factors for post-aSAH shunt dependence may benefit from increased surveillance, although the effect of such measures is not defined in this study.