Effect of shunt-dependency on long-term outcome after aneurysmal subarachnoid hemorrhage: a post-hoc analysis of the EARLYDRAIN prospective patient cohort

Shunt-dependent hydrocephalus is common after aneurysmal subarachnoid hemorrhage (aSAH) and has the risk to compromise the functional recovery of affected patients. This study investigated whether shunt-dependency is associated with the long-term outcome after aSAH. A post-hoc analysis was performed using the patient cohort of a prospective randomized controlled trial (EARLYDRAIN) conducted between 2011 and 2016. Patients were randomized for an early lumbar drainage (144 patients) or standard treatment alone (143 patients). Shunt insertion within 180 days after ictus was considered as shunt-dependency. The modified Rankin scale (mRS) at 180 days (mRS ≤ 2 equaling favorable outcome) was used for outcome assessment. The study population involved 287 aSAH patients with a mean age of 55 years. Shunt-dependent hydrocephalus was found in 29% of all patients. Patients without shunt-dependency had a better functional outcome at discharge (mRS 3.2 ± 2.0) compared to shunt-dependent patients (mRS 3.9 ± 1.5). Univariate analyses revealed worse functional outcome at 180 days in the patients with shunt-dependency compared to those without shung-dependency (mRS 2.8 ± 1.7, vs. mRS 2.2 ± 2.3). In multivariate analysis, adjusted for age, severity of the initial subarachnoid hemorrhage and the use of a lumbar drain, shunt-dependency was not associated with long-term outcome (p = 0.26). After correction for age, treatment and SAH-grade, shunt-dependency did not show an association with the outcome in aSAH patients after rehabilitation. Clinical improvement due to rehabilitation after shunt insertion may be the explanation why chronic hydrocephalus per se does not represent an independent factor associated with long-term outcome.