Localization of subarachnoidal hemorrhage and outcome: a retrospective, single center analysis

The outcome of acute subarachnoidal haemorrhage (aSAH) is highly variable and depends on the severity of the aSAH. The brain is characterized by an anterior and posterior cerebral circulation, which are interconnected through the circulus of Willis. An ischemic stroke in the posterior circulation has a different presentation and outcome, compared with an ischemic stroke in the anterior circulation. We hypothesized that aSAH in the posterior circulation results in a worse outcome, compared with an aSAH of the anterior circulation. This retrospective single center study analyzed patients who underwent a surgical procedure for aSAH from January 2017 until December 2021 at the Ziekenhuis Oost- Limburg’ ZOL, Genk, Belgium. Length of ICU and hospital stay and hospital mortality were the main outcome variables. Patients with an aSAH in the posterior circulation had a higher World Federation of Neurosurgical Societies (WFNS) and Fisher grade on admission. Higher WFNS grade resulted in longer duration of stay in ICU and hospital, and in a higher mortality rate. However, in multivariable logistic regression analysis the localization of the aSAH was not independently associated with mortality. While patients with an aSAH, deriving from an aneurysm in the posterior circulation, had a higher severity of stroke upon admission and a more complicated trajectory in the hospital the posterior localization was not independently associated with worse outcome.