Abstract Body: Introduction: Urgent external ventricular drain (EVD) placement in aneurysmal subarachnoid hemorrhage (aSAH) is necessary for hydrocephalus treatment. However, it is unclear whether more rapid EVD placement is associated with better neurologic outcomes. In addition, EVD placement before aneurysm securement is thought to decrease aneurysmal transluminal pressure and may increase the risk of aneurysmal rerupture. We sought to better characterize whether the intervals from arrival to EVD placement and from EVD placement to aneurysm treatment were associated with differences in aneurysmal rerupture rates or neurologic outcomes.
Methods: A retrospective study of a prospectively collected cohort of patients with aSAH presenting from 2015 to 2023 to a single academic center was performed. Multivariate logistic regressions (MLR) were performed to analyze the time from hospital arrival to EVD and both preprocedural aneurysm rerupture as well as poor neurologic outcomes, defined as a modified Rankin scale (mRS) >3 at 3 months. In addition, a similar analysis was performed with time from EVD to aneurysm securement.

Results: Out of 434 patients with ruptured aSAH, we excluded those who received urgent craniotomy or craniectomy, as well as those who did not undergo angiography due to early mortality or EVD placement due to lack of hydrocephalus, resulting in a cohort of 231 patients (mean [SD] age, 57.6 [13.5]; 67.5% female, 69.3% white). Longer arrival to EVD was associated with an increased risk of preprocedural aneurysmal rerupture (OR 1.93, 95%CI 1.05, 3.66, p=0.038); however, longer EVD to aneurysm securement was not associated with differences in preprocedural aneurysmal rerupture (OR 0.66, 95%CI [0.41, 1.09], p=0.093). On MLR, longer arrival to EVD or longer EVD to aneurysm securement was not associated with differences in 3-month neurologic outcomes (OR 1.13, 95%CI [0.73, 1.75], p=0.6 and OR 0.74, 95%CI [0.51, 1.05], p=0.095, respectively).

Conclusion: We found that longer arrival to EVD was associated with an increased risk of preprocedural rerupture, but not associated with differences in neurologic outcomes at 3 months. While EVD placement prior to aneurysmal securement is theorized to decrease transluminal pressure and increase rerupture risk, we did not find an association between duration from EVD placement to aneurysm securement and rerupture risk.