Neurofilament light chain as an early and sensitive predictor of long-term neurological outcome in patients after cardiac arrest

BACKGROUND: Neurofilament light chain (NF-L) is the major intermediate filament specifically expressed in neurons and their axons. No data are available concerning serum levels of NF-L after global cerebral ischemia due to cardiac arrest. To find a specific neuronal marker of long-term neurological outcome, we examined serum levels of NF-L in patients after cardiac arrest.

METHODS: A prospective observational cohort study was conducted. Blood samples for the measurement of NF-L were analyzed from 85 patients within 2h after admission, as well as on 2nd, 3rd, 5th, and 7th day. Neurological outcome was assessed 6 months after cardiac arrest by employing the Modified Glasgow Outcome Score (MGOS).

RESULTS: The serum course of NF-L in patients with poor neurological outcome (MGOS 1+2) was significantly augmented compared to patients with good neurological outcome (MGOS 3+4+5) (on admission (pg/ml): good: 125 ± 11.7 vs. poor: 884.4 ± 86.2 pg/ml; 3rd day: good: 153.1 ± 13.2 vs. poor: 854.4 ± 119.1; 7th day: good: 112.5 ± 10.4 vs. poor: 1011.8 ± 100.8; P<0.001). Intermediate NF-L serum values were found in patients with MGOS 0, which represents a mixture of patients who died with and without certified brain damage (on admission (pg/dl): 433.7 ± 49.8; 3rd day: 598.3 ± 86.6; 7th day: 474 ± 77.4). A prediction power of 0.93 (c-statistic, 95%-CI 0.87-0.99) on 1st, 0.85 (0.81-0.95) on 2nd, 0.92 (0.85-0.99) on 3rd, 0.97 (0.92-1) on 5th and 0.99 (0.98-1) on 7th day was achieved for NF-L predicting poor neurological outcome.

CONCLUSIONS: The present data suggest that within 7 days after cardiac arrest serum NF-L is a valuable marker of long-term neurological outcome.