Blutmenge im 4. Ventrikel nach aneurysmatische Subarachnoidalblutung: prognostische Bedeutung und Einfluss der aktiven Blut clearance.

Blood in the fourth ventricle is associated with particularly poor outcomes after aneurysmal subarachnoid hemorrhage (aSAH). We investigate a) the prognostic significance of 4^th-ventricular hemorrhage severity, and, b) the influence of active blood clearance on outcome in patients with 4^th ventricular hemorrhage.

A retrospective review of our aSAH database was performed, and 817 patients with aSAH admitted between 01.01.2009 and 31.12.2022 were included. Blood clearance by cisternal fibrinolysis was introduced in 10.2015 and the data set was split in two cohorts with 473 patients BEFORE availability of active blood clearance and 344 patients AFTER introduction of active blood clearance, which was performed in 111 (32.3%) patients. 4^th ventricular hemorrhage was classed into 4 categories: grade 1 (no or minimal blood), grade 2 (partly filled), grade 3 (completely filled/ cast), grade 4 (ballooning due to hemorrhage). Neurological outcome was assessed using the modified Rankin Scale after 6 months by an independent rater.

4^th-ventricular hemorrhage was present in 39.7% of patients. Ruptured aneurysms in the posterior circulation were associated with a higher risk for a high-grade (3-4) 4^th-ventricular hemorrhage (p=0.008). In the BEFORE cohort, patients with grade 3 and 4 hemorrhages had poor outcome in 75.6% and 92.7%, respectively. In the AFTER cohort, active blood clearance was performed in 24.7% (grade 3) and 31.7% (grade 4) of patients, and poor-outcome was reduced to 57.5% and 75.6% (p=0.043, p=0.017), respectively. Grade 4 hemorrhage was the most powerful predictor for poor-outcome (OR:19.2, p<0.001) without active blood clearance. This association, however, was reduced after implementation of active blood clearance (OR:2.45, p=0.075).

Ballooned 4^th ventricular hemorrhage represents a very powerful predictor of poor outcome after aSAH. Implementation of active blood clearance significantly improved outcomes in high-grade 4^th ventricular hemorrhage patients.