Rapid Rule-Out of Myocardial Infarction Using a Single High-Sensitivity Cardiac Troponin I Measurement Strategy at Presentation to the Emergency Department: The SAFETY Study

Abstract

Abstract Background Our study addressed the diagnostic performance of the Atellica® IM High-Sensitivity Troponin I (hs-cTnI) assay for the rapid rule-out of myocardial infarction (MI) using a single hs-cTnI measurement at presentation in patients presenting to a US emergency department (ED). Methods This was a prospective, observational, cohort study of consecutive ED patients with suspected acute coronary syndrome, using 12-lead electrocardiogram and serial hs-cTnI measurements ordered on clinical indication (SAFETY, NCT04280926). ST-segment elevation MI patients were excluded. The optimal threshold required a sensitivity ≥99% and a negative predictive value (NPV) ≥99.5% for MI during index hospitalization as primary outcome. Type 1 MI (T1MI), myocardial injury, and 30-day adverse events were considered secondary outcomes. Event adjudications were established using the hs-cTnI assay used in clinical care. Results In 1171 patients, MI occurred in 97 patients (8.3%), 78.3% of which were type 2 MI. The optimal rule out hs-cTnI threshold was <10 ng/L, which identified 519 (44.3%) patients as low risk at presentation, with sensitivity of 99.0% (95% CI, 94.4–100) and NPV of 99.8% (95% CI, 98.9–100). For T1MI, sensitivity was 100% (95% CI, 83.9–100) and NPV 100% (95% CI, 99.3–100). Regarding myocardial injury, the sensitivity and NPV were 99.5% (95% CI, 97.9–100) and 99.8% (95% CI, 98.9–100), respectively. For 30-day adverse events, sensitivity was 96.8% (95% CI, 94.3–98.4) and NPV 97.9% (95% CI, 96.2–98.9). Conclusions A single hs-cTnI measurement strategy enabled the rapid identification of patients at low risk of MI and 30-day adverse events, allowing potential discharge early after ED presentation. Clinicaltrials.gov Registration number NCT04280926.