BACKGROUND: High-sensitivity cardiac troponin assays enable the early risk stratification of patients with suspected acute coronary syndrome to identify those at low risk of myocardial infarction or cardiac death. We evaluated the performance of a novel high-sensitivity cardiac troponin I assay in early rule out pathways.
METHODS: In 1920 patients with suspected acute coronary syndrome, cardiac troponin was measured using the Siemens Atellica high-sensitivity cardiac troponin I assay (99th centile: 34 ng/L women, 53 ng/L men). We evaluated three pathways which use either low risk-stratification thresholds of cardiac troponin (High-SensitivityTroponin in the Evaluation of patients with Acute Coronary Syndrome (High-STEACS) and the European Society of Cardiology (ESC) 1 hour pathway) or the 99th centile diagnostic threshold (ESC 3 hour pathway) to rule out myocardial infarction.
RESULTS: The primary outcome of myocardial infarction or cardiac death at 30 days occurred in 14.4% (277/1920). The High-STEACS pathway ruled out 63% of patients (1218/1920), with five missed events for a negative predictive value (NPV) of 99.5% (95% CI (CI) 99.1% to 99.8%). Similar performance was observed for the ESC 1 hour pathway with an NPV of 99.0% (97.6% to 99.8%). In contrast, the ESC 3 hour pathway ruled out 65% of patients (1248/1920), but missed 25 events for an NPV of 98.0% (97.1% to 98.7%).
CONCLUSIONS: A novel high-sensitivity cardiac troponin I assay can safely identify patients at low risk of myocardial infarction or cardiac death. Diagnostic pathways that use low cardiac troponin concentrations for risk stratification miss fewer events than those that rely on the 99th centile to rule out myocardial infarction.
TRIAL REGISTRATION: NCT1852123.
The results of this study are very informative as they provide further evidence that early risk stratification of patients suspected to have acute coronary syndromes is feasible and practical. Early rule out of myocardial infarction can be particularly useful in terms of early patients discharge and possibly reduction of the costs of care.
This prospective observational cohort study focuses on a novel high-sensitivity Troponin I assay in the evaluation of patients with suspect Acute Coronary Syndrome. By using this approach, the authors demonstrated that the identification of low-risk patients may improve safety and decision making in the emergency department. On the other hand, this investigation showed a serious selection bias as samples for the evaluation of the ESC 1 hour pathway were available in only 20% of patients. Although the authors recognized the limitation, it should be better emphasized in both abstract and conclusion. In turn, the title is not appropriate.
We already recognize the usefulness of cTnI measurements as published in the Lancet (2015;386:2481). It is important how quickly the results are obtained. The results of this study also highlight the excellence of the ESC 0/1 pathway.