Objective:

To systematically evaluate evidence for microRNAs (miRNAs) as prognostic biomarkers of neurologic outcome after cardiac arrest.

Background:

Accurate neuroprognostication after cardiac arrest remains challenging due to limited reliable predictors. Ideal biomarkers should reflect hypoxic-ischemic brain injury and allow standardized, reproducible measurement. miRNAs have emerged as promising candidates because of their stability, detectability in body fluids, and role in gene regulation associated with cellular injury.

Design/Methods:

A systematic search of MEDLINE, EMBASE, and Cochrane Library databases was conducted using predefined terms related to cardiac arrest, neuroprognostication, and miRNA. Two independent reviewers screened and extracted data from eligible studies, with discrepancies resolved by a third reviewer. Study quality was assessed using the CEBM prognostic study checklist.

Results:

Twelve studies met inclusion criteria, encompassing 28 distinct miRNAs. miR-124 was the most frequently and consistently studied, followed by miR-122, miR-9, miR-483, and miR-574. Among all candidates, eight (miR-124, miR-9, miR-483, miR-125b, miR-129, miR-6511b, miR-let-7a, and miR-let-7c) demonstrated strong prognostic linkage, typically within 6–48 hours after return of spontaneous circulation. Prognostic accuracy varied, with reported AUC values up to 0.96. However, heterogeneity in sample timing, analytical methods, and outcome measures limited comparability and meta-analysis.

Conclusions:

Evidence supports several miRNAs, particularly miR-124, as promising biomarkers for neurologic prognostication following cardiac arrest. Current studies are heterogeneous and limited by small sample sizes and inconsistent methodologies. Future large-scale, standardized investigations should explore composite miRNA signatures and optimal sampling times to establish clinical utility in post–cardiac arrest neuroprognostication.