A 0/1-Hour Algorithm Using High-Sensitivity Cardiac Troponin.

Abstract

The European Society of Cardiology (ESC) guidelines recommend the use of high-sensitivity cardiac troponin (hs-cTn) 0-hour/1-hour algorithms in patients presenting with suspected non ST elevation myocardial infarction (NSTEMI) as Class I, Level B. This algorithm stratified patients into three group including, rule-out, observe, and rule-in. The introduction of a time axis consisting of a relatively short time, 0-hour/1-hour, is worth mentioning in this algorithm. The specificity and negative predictive value to rule-out of myocardial infarction (MI) was more than 95%, respectively. In prospective Asian study consist of around 400 patients with suspected NSTEMI, "elective" catheter intervention was performed on 13 patients in both rule-out and observe group. None of them had MI, or needed an urgent coronary angiography (CAG) within 30 days. Although there was two patients on whom CAG and percutaneous coronary intervention (PCI) were performed less than 7 hours after presenting to the emergency department (ED), they were classified as moderate risk according to the Framingham Risk Score. The diagnostic performance for patients with suspected NSTEMI to combine the novel risk score with the algorithm would be much improved. The development of excellent assays was also key to establish the algorithm. The hs-cTn assay has limits of detection (LoD) approximately 10-fold lower than those of conventional assays, and their 99th percentiles are analytically very precise. After the emergence of the hs-cTn assays, rises in the cases of NSTEMI were accompanied by a reciprocal reduction in the percentage of patients diagnosed with unstable angina (UA). This excellent algorithm has a possibility to reduce ED crowding and unnecessary CAG.