MicroRNAs as Biomarkers of Short-Term Complications After Cardiac Surgery.

Cardiac surgery carries substantial risk of early postoperative complications including postoperative atrial fibrillation (POAF, 30-50%), periprocedural myocardial infarction (PMI), acute kidney injury (AKI, 3.8-54.4%), bleeding (3-5%), stroke, and cognitive dysfunction. This narrative review synthesizes 30+ studies on circulating microRNAs (miRNAs) as perioperative biomarkers, identifying strongest evidence for cardiac-enriched miR-499 (AUC 0.93, sensitivity 85.7%, specificity 93.3%) and miR-133a (peaks 1-3 h post-declamping) in PMI diagnosis -outperforming troponins' 6h kinetics. POAF prediction favors preoperative miR-483-5p (AUC 0.78), while AKI, bleeding (miR-223), and neurological injury show emerging but less validated candidates (miR-21, miR-210-3p). We critically analyze limitations across studies and outline clinical translation barriers (3-6 h assay times, heparin inhibition, lacking standardization) with solutions for point-of-care implementation.