Results:

The most important clinical advantage of the new, more-sensitive cTn assays is their ability to substantially reduce the initial “troponin-blind” interval in the first hours after MI onset and to allow novel, rapid strategies for the early rule-out or rule-in of MI. It is important to highlight several aspects when applying troponin-based strategies in clinical practice. First, they should be used only in conjunction with full clinical assessment, including a pretest probability assessment to identify those patients at high risk who may not be suitable for early discharge. Second, these strategies should be considered triage strategies rather than definite diagnostic strategies, as additional imaging tests (e.g., invasive coronary angiography, stress testing, echocardiography, or computed tomography angiography) may be necessary for a definite diagnosis. Third, the percentage of patients eligible for rule-out or rule-in varies widely from 9.8% to 77% depending on the underlying algorithm, the cTn assay used, and the clinical setting including the prevalence of MI. Fourth, these strategies should only be applied after the initial electrocardiogram (ECG) has excluded ST-segment elevation MI since these high-risk patients need prompt identification based on the ECG and immediate reperfusion therapy without the need for cTn testing. Finally, to maximize utility, all triage strategies should be embedded in the local standard operating procedures of the ED.