Two-Hour Algorithm for Triage toward Rule-Out and Rule-In of Acute Myocardial Infarction by Use of High-Sensitivity Cardiac Troponin I

• Published in: Clinical chemistry (Baltimore, Md.) Vol. 62; no. 3; pp. 494 - 504
• Main Authors: Boeddinghaus, Jasper, Reichlin, Tobias, Cullen, Louise, Greenslade, Jaimi H, Parsonage, William A, Hammett, Christopher, Pickering, John W, Hawkins, Tracey, Aldous, Sally, Twerenbold, Raphael, Wildi, Karin, Nestelberger, Thomas, Grimm, Karin, Rubini Gimenez, Maria, Puelacher, Christian, Kern, Vera, Rentsch, Katharina, Than, Martin, Mueller, Christian
• Format: Journal Article
• Language: English
• Published: England Oxford University Press 01.03.2016
• Subjects: Accuracy; Acute coronary syndromes; Algorithms; Cardiovascular disease; Clinical medicine; Female; Funding; Heart attacks; Hospitals; Humans; Hypothesis testing; Laboratories; Limit of Detection; Male; Middle Aged; Myocardial infarction; Myocardial Infarction - blood; Myocardial Infarction - mortality; Pain; Predictive Value of Tests; Prospective Studies; Studies; Time Factors; Troponin I - blood
• ISSN: 0009-9147; 1530-8561
• DOI: 10.1373/clinchem.2015.249508

The early triage of patients toward rule-out and rule-in of acute myocardial infarction (AMI) is challenging. Therefore, we aimed to develop a 2-h algorithm that uses high-sensitivity cardiac troponin I (hs-cTnI). We prospectively enrolled 1435 (derivation cohort) and 1194 (external validation cohort) patients presenting with suspected AMI to the emergency department. The final diagnosis was adjudicated by 2 independent cardiologists. hs-cTnI was measured at presentation and after 2 h in a blinded fashion. We derived and validated a diagnostic algorithm incorporating hs-cTnI values at presentation and absolute changes within the first 2 h. AMI was the final diagnosis in 17% of patients in the derivation and 13% in the validation cohort. The 2-h algorithm developed in the derivation cohort classified 56% of patients as rule-out, 17% as rule-in, and 27% as observation. Resulting diagnostic sensitivity and negative predictive value (NPV) were 99.2% and 99.8% for rule-out; specificity and positive predictive value (PPV) were 95.2% and 75.8% for rule-in. Applying the 2-h algorithm in the external validation cohort, 60% of patients were classified as rule-out, 13% as rule-in, and 27% as observation. Diagnostic sensitivity and NPV were 98.7% and 99.7% for rule-out; specificity and PPV were 97.4% and 82.2% for rule-in. Thirty-day survival was 100% for rule-out patients in both cohorts. A simple algorithm incorporating hs-cTnI baseline values and absolute 2-h changes allowed a triage toward safe rule-out or accurate rule-in of AMI in the majority of patients.