Predictors of Ventriculoperitoneal shunting following Subarachnoid Hemorrhage treated with External Ventricular Drainage

Background/Objectives: Aneurysmal subarachnoid hemorrhage (aSAH) is commonly associated with hydrocephalus due to subarachnoid hemorrhage blood products obstructing cerebrospinal fluid outflow. Hydrocephalus after aSAH is routinely managed with temporary external ventricular drainage (EVD) followed by standard EVD weaning protocols, which determine the need for ventriculoperitoneal shunting (VPS). We sought to investigate aSAH patients who initially passed EVD weaning trials and had EVD removal, but later presented with recurrent, delayed, symptomatic hydrocephalus requiring a VPS. Methods: We conducted a retrospective review of all patients at our tertiary care medical center who presented with aSAH, requiring an EVD. We analyzed variables associated with ultimate VPS dependency during hospitalization. Results: We reviewed 489 patients with aSAH over a 6-year period (2008–2014). One hundred and thirty-eight (28.2%) developed hydrocephalus requiring a temporary EVD. Forty-four (31.9%) of these patients died or had withdrawal of care during admission, and were excluded from final analysis. Of the remaining 94 patients, 29 (30.9%) failed their clamp trial and required VPS. Sixty-five (69.1%) patients passed their clamp trial and were discharged without a VPS. However, 10 (15.4%) of these patients developed delayed hydrocephalus after discharge and ultimately required VPS [mean (range) days after discharge, 97.2 (35–188)]. Compared to early VPS, the delayed VPS group had a higher incidence of symptomatic vasospasm (90.0% vs 51.7%; P = 0.03). When comparing patients discharged from the hospital without VPS, delayed VPS patients also had higher 6- and 12-month mortality (P = 0.02) and longer EVD clamp trials (P < 0.01) than patients who never required VPS but had an EVD during hospitalization. Delayed hydrocephalus occurred in only 7.8% of patients who passed the initial EVD clamp trial, compared to 14.3% who failed the initial trial and 80.0% who failed 2 or more trials. Conclusion: Patients who failed their initial or subsequent EVD clamp trials had a small, but increased risk of developing delayed hydrocephalus ultimately requiring VPS. Additionally, the majority of patients who presented with delayed hydrocephalus also suffered symptomatic vasospasm. These associations should be further explored and validated in a larger prospective study.