Protein S100B as a reliable tool for early prognostication after cardiac arrest

Purpose: Early and reliable prognostication after cardiac arrest (CA) remains crucial. We hypothesized that protein-S100B (PS100B) could predict more accurately outcome in the early phase of CA compared with other current biomarkers.

Methods: This prospective single-center study included 330 adult comatose non-traumatic successfully resuscitated CA patients, treated with targeted temperature management but not extra-corporeal life support. Lactate, pH, creatinine, NSE, and PS100B were sampled in ICU early after return of spontaneous circulation (ROSC) corresponding to admission (Adm). Serial measurements were also performed at H24 and H48. PS100B was the sole biomarker blinded to physicians.

Measurements and main results: The median delay between ROSC and first PS100B sampling was 220 min. At admission, all biomarkers were significantly associated with good outcome (CPC1-2; 109 patients) at 3-month follow-up (P ≤ 0.001, except for NSE: P = 0.03). PS100B-Adm showed the best AUC of ROC curves for outcome prediction at 3-month (AUC 0.83 [95%-CI: 0.78-0.88]), compared with other biomarkers (P < 0.0001), while AUC for lactate-Adm was higher than for NSE-Adm. AUC for PS100B-H24 was significantly higher than for other biomarkers except NSE-H24 (P ≤ 0.0001), while AUC for NSE-H24 was higher than for lactate-H24 and pH-H24. AUCs for PS100-H48 and NSE-H48 were significantly higher than for all other biomarkers (P < 0.001). Compared to patients with decreased PS100B values over time, an increasing PS100B value between admission and H24 was significantly associated with poor outcome at 3 months (P = 0.001). No-flow, initial non-shockable rhythm, PS100B-Adm, lactate-Adm, pH-Adm, clinical seizures, and absence of therapeutic hypothermia were independent predictors associated with poor outcome at 3-month in multivariate analysis. Net-Reclassification-Index was 70%, 64%, and 81% when PS100B-Adm was added to the clinical model, to clinical model with NSE-Adm, and to clinical model with standard biological parameters, respectively.

Conclusions: Early PS100B compared with other biomarkers was independently correlated with outcome after CA, with an interesting added value.