383 Neurofilament Light Chain as a Marker for Cerebral Anoxia in Out-of-Hospital Cardiac Arrest

Abstract

Nationwide survival rates for out-of-hospital cardiac arrest (OHCA) approximate around 10-20% despite aggressive intervention. Approximately 90% of survivors will have moderate to severe neurological injury ranging from moderate cognitive impairment to brain death. There is a lack of early prognostic indicators. Traumatic brain injury studies have demonstrated that levels of blood biomarkers of neurological injury are reflective of degree of injury sustained. These biomarkers may be of prognostic value in OHCA patients where anoxic cerebral injury occurs. Non-traumatic OHCA patients ≥ 18 years old, with sustained return of spontaneous circulation (ROSC) for >1 hour were prospectively enrolled. Blood was collected within 59 minutes of ROSC, every 6 hours the first 24 hours, and then daily up to day 6. Patients were followed to day 6 post-OHCA, hospital discharge, or death, whichever occurred first. APACHE II and FOUR scores were recorded daily from time of ROSC (baseline) up to day 6. Five biomarkers of neuroinjury were analyzed: NF-L, GFAP, UCHL-1, Tau, and S100B. Cerebral Performance Category (CPC) was determined at 24 hours of ROSC and by death or within 24 hours before discharge. Primary outcomes were survival to discharge, and good versus poor (CPC 1-2 versus CPC 3-5) neurological outcome at 24 hours and discharge. The association between the biomarkers and other variables were assessed by using the Wilcoxon rank-sum test. Person correlation coefficient was used to assess the relationship between the biomarkers and continuous variables. All tests were performed with a 5% error rate. 13 OHCA patients were enrolled. Participants were mostly males (62%) with an average age of 60.5±9.6 (range 42-73) years. Their presenting rhythm was most often asystole (30.8%), VT/VF (46.2%), or PEA (23.1%). 38.5% of patients survived to discharge. Mean APACHE II at baseline did not significantly differ at 24 hours (26.38 versus 26.31). Of the biomarkers assayed, mean NF-L was significantly different between good versus poor outcome at 24 hours (1244.74 pg/mL versus 966.22 pg/mL, p=0.018), and remained consistently higher in poor outcome group at discharge (21.84 pg/mL versus 1556.46 pg/mL, p=0.012). NF-L levels also correlated with FOUR score at baseline and at 24 hours (p=0.026 and 0.027 respectively), as well as GCS at baseline and 24 hours (p=0.016). Early serum biomarker assays may be supportive in correlating with clinical outcomes and prognostication in out-of-hospital cardiac arrest. We report early pilot data demonstrating the promise of neurofilament light chain as a part of a strategy in supporting the clinical assessment of ischemic brain injury in post cardiac arrest patients.