Two hour algorithm for triage towards rule-out and rule-in of acute myocardial infarction using high-sensitivity cardiac Troponin T.
Am J Med. 2014 Nov 13;
Authors: Reichlin T, Cullen L, Parsonage WA, Greenslade J, Twerenbold R, Moehring B, Wildi K, Mueller S, Zellweger C, Mosimann T, Rubini-Giménez M, Rentsch K, Osswald S, Mueller C
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 was measured at presentation and after two hours. A diagnostic algorithm incorporating hs-cTnT 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<0.001) in patients classified as "rule-out", "observational-zone" and "rule-in" in the two cohorts respectively.
CONCLUSIONS: A simple algorithm incorporating hs-cTnT baseline values and absolute changes over two hours allowed a triage towards safe rule-out, or accurate rule-in, of AMI in the vast majority of patients with only 20% requiring more prolonged monitoring and serial blood sampling.
PMID: 25446294 [PubMed - as supplied by publisher]