Absolute serum neurofilament light chain levels and its early kinetics predict brain injury after out-of-hospital cardiac arrest

OBJECTIVES: To test if the early kinetics of neurofilament light (NFL) in blood adds to the absolute values of NFL in the prediction of outcome, and to evaluate if NFL can discriminate individuals with severe hypoxic–ischemic brain injury (sHIBI) from those with other causes of poor outcome after out-of-hospital cardiac arrest (OHCA). DESIGN AND SETTING: Monocentric retrospective study involving individuals following non-traumatic OHCA between April 2014 and April 2016. NFL concentrations were determined on a SiMoA HD-1 device using NF-Light Advantage Kits. PARTICIPANTS: Of 73 patients screened, 53 had serum samples available for NFL measurement at three timepoints (after 3, 24, and 48 h of admission). Of these 53 individuals, 43.4% had poor neurologic outcome at discharge as assessed by Glasgow–Pittsburgh cerebral performance categories, and, according to a current prognostication algorithm, poor outcome due to sHIBI in 20.7%. MAIN OUTCOME MEASURE: Blood NFL and its early kinetics for prognostication of outcome and prediction of sHIBI after OHCA. RESULTS: An absolute NFL > 508.6 pg/ml 48 h after admission, or a change in NFL > 494 pg/ml compared with an early baseline value predicted outcome, and discriminated severe sHIBI from other causes of unfavorable outcome after OHCA with high sensitivity (100%, 95%CI 70.0–100%) and specificity (91.7%, 95%CI 62.5–100%). CONCLUSIONS: Not only absolute values of NFL, but also early changes in NFL predict the outcome following OHCA, and may differentiate sHIBI from other causes of poor outcome after OHCA with high sensitivity and specificity. Our study adds to published data, overall corroborating that NFL measured in blood should be implemented in prognostication algorithms used in clinical routine.