263 Neurofilament light chain is a predictor of outcome after aneurysmal subarach- noid haemorrhage

BackgroundThe best predictor of clinical outcome after aneurysmal subarachnoid haemorrhage (aSAH) is the World Federation of Neurological Surgeons (WFNS) score. Yet, this marker of early brain injury only explains 12% of the variance in outcome. Prolonged neurotoxicity via extracellular haemoglobin (Hb) may play a role. Neurofilament light chain (NFL) is released during neuronal damage. We hypothesize that CSF NFL predicts clinical outcome after aSAH and reflects Hb-induced neurotoxicity.MethodsCSF was collected via an external ventricular drain from 44 high-grade aSAH patients over 14 days post-ictus, and via lumbar puncture from 11 non-haemorrhagic, non-inflammatory neurologi- cal control patients. NFL and Hb were measured using enzyme-linked immunosorbent assay and ultra- performance liquid chromatography respectively. Clinical outcome after aSAH was assessed using the modified Rankin Score (mRS).ResultsNFL was higher in aSAH versus control CSF. High CSF NFL and high WFNS independently predicted worse mRS. CSF NFL was a stronger predictor than WFNS. Post-ictus, NFL and Hb CSF concentration gradually increased over two weeks. Maximum CSF NFL was correlated with maximum preceding CSF Hb, but not WFNS.ConclusionThe biomarker NFL is a predictor of clinical outcome after aSAH. NFL concentration likely reflects delayed Hb-induced neurotoxicity rather than early brain injury.pg1p07@soton.ac.uk