Shunt-Dependent Hydrocephalus and Cognitive Outcomes After Aneurysmal Subarachnoid Hemorrhage

Hydrocephalus is a common complication after aneurysmal subarachnoid hemorrhage (aSAH), frequently requiring permanent cerebrospinal fluid (CSF) diversion. The relationship between chronic, shunt-dependent hydrocephalus and cognitive outcomes after aSAH remains poorly defined. This study evaluated whether patients requiring permanent CSF diversion demonstrate worse cognitive outcomes at 90 days after aSAH.

A post hoc analysis of the multicenter NEWTON-2 clinical trial data set was conducted. Patients with ruptured saccular aneurysms (World Federation Neurosurgical Societies 2-4) who had Montreal Cognitive Assessment (MoCA) scores available at 90 days were included. Patients undergoing ventriculoperitoneal shunt placement were classified as having chronic hydrocephalus. The primary outcome was MoCA score at 90 days. Negative binomial regression was used to model MoCA scores, and logistic regression was performed using a clinically validated cutoff for cognitive impairment (MoCA ≤25). Multivariable models adjusted for age, sex, hypertension, World Federation Neurosurgical Societies grade, and delayed cerebral ischemia.

Among 215 patients with available 90-day MoCA scores, 77 (36%) required permanent CSF diversion. Median MoCA scores were lower in shunted patients compared with nonshunted patients (24 [IQR 16-26] vs 26 [IQR 22-28], P = .0007). Shunt placement was independently associated with increased odds of cognitive impairment at 90 days (odds ratio 2.13, 95% CI, 1.11-4.14) and an approximately 2.7-point reduction in MoCA scores after adjustment for covariates.

Permanent CSF diversion after aSAH is independently associated with worse cognitive performance at 90 days. Shunt-dependent hydrocephalus may identify patients at increased risk for persistent cognitive impairment who may benefit from enhanced monitoring and targeted rehabilitation.