Single troponin measurement to rule-out acute myocardial infarction in early presenters.

BACKGROUND: A single high-sensitive cardiac troponin (hs-cTn) can be used to rule-out acute myocardial infarction (MI) in patients presenting >3 hours (3 h) after chest pain onset to the emergency department. This study aimed to investigate the safety of ruling-out MI in early presenters with chest pain ≤3 h using a single hs-cTnI at admission. METHODS: We prospectively enrolled patients presenting with chest pain suggestive of MI. Hs-cTnI (Siemens ADVIA Centaur TNIH, Limit of detection: 2.2 ng/L) was measured at admission. Two physicians adjudicated final diagnosis. A diagnostic cut-off value <3 ng/L was used to rule-out MI. Patients were classified as early (chest pain ≤3 h) or late presenters (>3 h). RESULTS: We included 1370 patients with available admission hs-cTnI results: median (Q1-Q3) age 65 (52-74), female sex: 43%, previous MI: 22%. We confirmed MI in 118 (8.6%) patients. Overall, 470 (34%) patients were classified as early, 770 (56%) as late presenters, and 130 (9%) patients had unknown onset. When applying the diagnostic cut-off value, MI was correctly ruled-out at admission in 370 (27%) patients: 134 (29%) early presenters, 206 (27%) late presenters and 30 (23%) patients with unknown onset. This resulted in an overall negative predictive value of 100% (95% CI: 99.0-100%), with both 100% (97.3-100%) for early and 100% (98.2-100%) for late presenters, respectively. Sensitivity was similarly high in the two groups. CONCLUSION: MI could be safely ruled-out in all patients presenting with chest pain ≤3 h when using a single hs-cTnI value <3 ng/L as diagnostic cut-off. TRIAL REGISTRATION NUMBER: NCT03634384.