Two-hour algorithm for triage toward rule-out and rule-in of acute myocardial infarction using high-sensitivity cardiac troponin T

ABSTRACT Background: High-sensitivity cardiac troponin (hs-cTn) may allow an earlier diagnosis of acute myocardial infarction (AMI). Methods: We prospectively enrolled 1148 (derivation cohort) and 517 (external validation cohort) unselected patients presenting with suspected AMI to the emergency department. Final diagnosis was adjudicated by two independent cardiologists. Hs-cTnT wasmeasured at presentation and after two hours. A diagnostic algorithm incorporating hscTnT values at presentation and absolute changes within the first two hours was derived. Results: AMI was the final diagnosis in 16% of patients in the derivation and 9.1% in the validation cohort. The 2h algorithm developed in the derivation cohort classified 60% of patients as “rule-out”, 16% as “rule-in” and 24% in the “observational- zone”. Resulting sensitivity and negative predictive value (NPV) were 99.5% and 99.9% for rule-out, and specificity and positive predictive value (PPV) 96% and 78% for rule-in. Applying the 2h triage algorithm in the external validation cohort, 78% of patients could be classified as “rule-out”, 8% as “rule-in” and 14% in the “observational-zone”. Resulting sensitivity and NPV were 96% and 99.5% for rule-out and specificity and PPV 99% and 85% for rule-in. Cumulative 30-day survival rates were 100%, 98.9% and 95.2% (p<0.001) and 100%,100% and 95% (p