Gradual External Ventricular Drainage Weaning Reduces The Risk of Shunt Dependency After Aneurysmal Subarachnoid Hemorrhage: A Pooled Analysis

BACKGROUND: Chronic posthemorrhagic hydrocephalus necessitating shunt placement is a common complication of subarachnoid hemorrhage (SAH). OBJECTIVE: To evaluate the role of external ventricular drainage (EVD) weaning on risk of shunt dependency after SAH. METHODS: Two German university hospitals with different EVD management regimes (rapid weaning [RW] vs gradual weaning [GW]) pooled the data of their observational cohorts containing altogether 1171 consecutive SAH patients treated between January 2005 and December 2012. Development and timing of shunt dependency in SAH survivals were the endpoints of the study. RESULTS: The final cohort consisted of 455 and 510 SAH survivors treated in the centers with RW and GW, respectively. Mortality rates, as well as baseline demographic, clinical, and radiographic parameters, showed no differences between the centers. Patients with GW were less likely to develop shunt dependency (27.5% vs 34.7%, P = .018), Multivariate analysis confirmed independent association between RW regime and shunt dependency (P = .026). Shunt-dependent SAH patients undergoing GW required significantly longer time until shunting (mean 29.8 vs 21.7 d, P < .001) and hospital stay (mean 39 vs 34.4 d, P = .03). In addition, patients with GW were at higher risk for secondary shunt placement after successful initial weaning (P = .001). The risk of cerebrospinal fluid infection was not associated with the weaning regime (15.3% vs 12.9%, P = .307). CONCLUSION: At the expense of longer treatment, GW may decrease the risk of shunt dependency after SAH without an additional risk for infections. Due to the risk of secondary shunt dependency, SAH patients with GW require proper posthospital neurological care.