Blood Biomarker Predicts Cognitive Outcomes After Cardiac Arrest

Long-term cognitive impairment is a frequent consequence of out-of-hospital cardiac arrest yet early prediction remains difficult. Clinicians commonly use blood-based markers to estimate brain injury risk during hospitalization, but current tools have limitations. Better prognostic indicators could guide imaging, rehabilitation, and family counseling. A new study now shows that early measurement of neurofilament light chain (NfL) in blood may improve identification of patients at high risk of later cognitive dysfunction.

New data presented at ESC Acute CardioVascular Care 2026, the annual congress of the Association for Acute CardioVascular Care, shows that early blood testing for NfL may better predict long-term cognitive impairment after out-of-hospital cardiac arrest (OHCA). Investigators compared NfL with the current standard biomarker, neuron-specific enolase (NSE), for assessing later cognitive outcomes.

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Researchers analyzed blood samples from participants in the Blood Pressure and Oxygenation Targets after Cardiac Arrest (BOX) trial who had been resuscitated from OHCA and were comatose on admission. NfL and NSE were measured in samples collected 48 hours after the cardiac arrest. Cognitive function was assessed months later using the Montreal Cognitive Assessment (MoCA), with analyses restricted to survivors who had both biomarker measurements and outcome data.

NfL concentrations at 48 hours were inversely correlated with MoCA score, indicating that higher NfL levels were associated with worse long-term cognitive function. In contrast, NSE levels at 48 hours showed no association with cognitive outcomes at follow-up. According to the investigators, routine early NfL testing could help identify high-risk patients, inform decisions about additional tests and scans, and support targeted rehabilitation, pending further validation and standardization of NfL assays.

“Neurofilament light chain levels measured early after cardiac arrest, while patients were still admitted to hospital, were related to long-term cognitive function. This association with cognitive function was not observed with neuron-specific enolase testing," said study presenter Doctor Martin Meyer, Rigshospitalet – Copenhagen University, Denmark. "The introduction of routine early neurofilament light chain measurement could potentially assist in the identification of patients at high risk, helping to optimise decision-making about other tests and scans, improve the targeting of rehabilitation and enable clinicians to better inform patients and their families about expectations for the future. Further validation and standardisation of neurofilament light chain assays are now needed.” 

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ESC Association for Acute CardioVascular Care