Objective
In the first days after cardiac arrest, accurate prognostication is challenging. Serum biomarkers are a potentially attractive adjunct for prognostication and risk stratification. Our primary objective in this exploratory study was to identify novel early serum biomarkers that predict survival after cardiac arrest earlier than currently possible.
Design
Prospective, observational study
Setting
A single academic medical center
Subjects
Adult subjects who sustained cardiac arrest with return of spontaneous circulation
Intervention
None
Measurements and Main Results
We obtained blood samples from each subject at enrollment, 6, 12, 24, 48 and 72 hours after return of spontaneous circulation. We measured serum levels of novel biomarkers including neutrophil gelatinase-associated lipocalin (NGAL), high-mobility group protein B1 (HMGB), intracellular cell adhesion molecule 1 (ICAM-1) and leptin, as well as previously characterized biomarkers including neuron specific enolase (NSE) and S100B protein. Our primary outcome of interest was survival to hospital discharge. We compared biomarker concentrations at each time point between survivors and non-survivors and used logistic regression to test the unadjusted associations of baseline clinical characteristics and enrollment biomarker levels with survival. Finally, we constructed a series of adjusted models to explore the independent association of each enrollment biomarker level with survival.
A total of 86 subjects were enrolled. Enrollment levels of HMGB, NGAL and S100B were higher in non-survivors than survivors. Enrollment leptin, NSE and ICAM-1 levels did not differ between non-survivors and survivors. The discriminatory power of enrollment NGAL level was greatest (c-statistic 0.78 (95%CI 0.66 – 0.90), and remained stable across all time points. In our adjusted models, enrollment NGAL level was independently associated with survival even after controlling for development of acute kidney injury and its addition to clinical models improved overall predictive accuracy.
Conclusion
Serum NGAL levels are strongly predictive of survival to hospital discharge after cardiac arrest.