Successful weaning versus permanent cerebrospinal fluid diversion after aneurysmal subarachnoid hemorrhage: post hoc analysis of a Swiss multicenter study
Authors: El-Garci Ahmed , Zindel-Geisseler Olivia , Dannecker Noemi , Rothacher Yannick , Schlosser Ladina , Zeitlberger Anna , Velz Julia , Sebök Martina , Eggenberger Noemi , May Adrien , Bijlenga Philippe , Guerra-Lopez Ursula , Maduri Rodolfo , Beaud Valérie , Starnoni Daniele , Chiappini Alessio , Rossi Stefania , Robert Thomas , Bonasia Sara , Goldberg Johannes , Fung Christian , Bervini David , Gutbrod Klemens , Maldaner Nicolai , Früh Severin , Schwind Marc , Bozinov Oliver , Neidert Marian C. , Brugger Peter , Keller Emanuela , Germans Menno R. , Regli Luca , Hostettler Isabel C. , Stienen Martin N. , _ _ , _ _ , Krayenbühl Niklaus , Esposito Giuseppe , Moiraghi Alessandro , Starnoni Daniele , Rocca Alda , Seule Martin A. , Weyerbrock Astrid , Hlavica Martin , Mueller Mandy 
Published: April 2023

OBJECTIVE
Acute hydrocephalus is a frequent complication after aneurysmal subarachnoid hemorrhage (aSAH). Among patients needing CSF diversion, some cannot be weaned. Little is known about the comparative neurological, neuropsychological, and health-related quality-of-life (HRQOL) outcomes in patients with successful and unsuccessful CSF weaning. The authors aimed to assess outcomes of patients by comparing those with successful and unsuccessful CSF weaning; the latter was defined as occurring in patients with permanent CSF diversion at 3 months post-aSAH.

METHODS
The authors included prospectively recruited alert (i.e., Glasgow Coma Scale score 13–15) patients with aSAH in this retrospective study from six Swiss neurovascular centers. Patients underwent serial neurological (National Institutes of Health Stroke Scale), neuropsychological (Montreal Cognitive Assessment), disability (modified Rankin Scale), and HRQOL (EuroQol-5D) examinations at < 72 hours, 14–28 days, and 3 months post-aSAH.

RESULTS
Of 126 included patients, 54 (42.9%) developed acute hydrocephalus needing CSF diversion, of whom 37 (68.5%) could be successfully weaned and 17 (31.5%) required permanent CSF diversion. Patients with unsuccessful weaning were older (64.5 vs 50.8 years, p = 0.003) and had a higher rate of intraventricular hemorrhage (52.9% vs 24.3%, p = 0.04). Patients who succeed in restoration of physiological CSF dynamics improve on average by 2 points on the Montreal Cognitive Assessment between 48–72 hours and 14–28 days, whereas those in whom weaning fails worsen by 4 points (adjusted coefficient 6.80, 95% CI 1.57–12.04, p = 0.01). They show better neuropsychological recovery between 48–72 hours and 3 months, compared to patients in whom weaning fails (adjusted coefficient 7.60, 95% CI 3.09–12.11, p = 0.02). Patients who receive permanent CSF diversion (ventriculoperitoneal shunt) show significant neuropsychological improvement thereafter, catching up the delay in neuropsychological improvement between 14–28 days and 3 months post-aSAH. Neurological, disability, and HRQOL outcomes at 3 months were similar.

CONCLUSIONS
These results show a temporary but clinically meaningful cognitive benefit in the first weeks after aSAH in successfully weaned patients. The resolution of this difference over time may be due to the positive effects of permanent CSF diversion and underlines its importance. Patients who do not show progressive neuropsychological improvement after weaning should be considered for repeat CT imaging to rule out chronic (untreated) hydrocephalus.