Contemporary Approaches to Prehospital Acute Coronary Syndrome Risk Stratification: A Narrative Review.

Chest pain is a common high-risk complaint encountered by emergency medical services (EMS). Early identification and treatment of acute coronary syndromes (ACS) improve outcomes, yet prehospital evaluation remains constrained by limited diagnostic resources. This narrative review examines contemporary approaches to prehospital ACS risk stratification, diagnostic technologies, and decision-making. A targeted PubMed search of peer-reviewed publications and selected grey literature published between 2020 and 2025 was supplemented by targeted searches and citation review. Relevant literature published after the initial search period was incorporated during manuscript preparation and revision. Studies addressing prehospital ACS risk stratification, electrocardiogram (ECG) assessment, point-ofcare biomarkers, artificial intelligence (AI)-assisted diagnostics, and systems-level cardiac triage were included and synthesized thematically. Biomarker-integrated pathways, particularly HEART-derived approaches combined with point-of-care troponin testing, demonstrated the strongest evidence for safe prehospital risk assessment and reduced healthcare utilization. Biomarker-free approaches offered broader applicability but lower diagnostic certainty. ECG acquisition and transmission remained foundational for STEMI recognition and activation, while AI-assisted ECG interpretation and decision-support tools showed promising diagnostic performance but lacked prospective outcome-based validation. Gaps remain regarding atypical presentations, sex-specific strategies, and validation across diverse EMS environments. Overall, contemporary evidence supports structured prehospital risk stratification as decision support rather than definitive diagnosis. Implementation depends on provider training, protocol standardization, resources, and integration within regional systems of care. Future research should prioritize validation across diverse EMS settings, atypical and sex-specific presentations, and prospective evaluation of emerging diagnostic technologies.