Blood biomarkers for brain injury in chronic subdural hematomas: postoperative dynamics and relation to long-term outcome

Abstract

Objective: The aim of this study was to investigate whether the biomarkers neuron-specific enolase (NSE), glial fibrillary acidic protein (GFAP), neurofilament light chain (NfL), and tau (total [t] and brain-derived [BD]) are elevated in plasma preoperatively; if there is a dynamic biomarker response to surgery; and if the biomarker levels are related to long-term outcome in chronic subdural hematomas (CSDHs).

Methods: Eighty-five CSDH patients surgically treated between 2022 and 2023 at Uppsala University Hospital, Uppsala, Sweden, were included in this prospective, observational study. NSE, GFAP, NfL, t-tau, and BD-tau were evaluated in plasma pre- and postoperatively (6-24 hours after surgery) and in the CSDH fluid. Health-related quality of life was evaluated using the 5-level EQ-5D (EQ-5D-5L) at 6 months postoperatively.

Results: GFAP, NfL, and tau levels decreased after CSDH surgery (p < 0.02). NSE and BD-tau levels also decreased, but not significantly. Older age and larger CSDH volume were associated with higher preoperative GFAP, NfL, and BD-tau levels (p < 0.05). Higher preoperative values and greater dynamics (Δ [postoperative value - preoperative value]) of GFAP, NfL, and BD-tau correlated significantly with worse levels of several EQ-5D-5L domains (p < 0.05). A higher preoperative NfL level in plasma was independently associated with a lower EQ-5D-5L visual analog scale score (p < 0.001).

Conclusions: Surgical CSDH patients exhibit ongoing central nervous system cellular injury, demonstrated via increased fluid biomarkers for brain injury preoperatively, which immediately improved after surgery and was strongly related to long-term outcome. The extent of preoperative biomarker elevation could aid in the decision-making for surgical indication and urgency.

Keywords: biomarkers; chronic subdural hematoma; glial fibrillary acidic protein; neurofilament light chain; neuron-specific enolase; tau; traumatic brain injury.