Challenging the 99th percentile: A lower troponin cutoff leads to low mortality of chest pain patients

Background: Rule-out of non-ST-elevation myocardial infarction is based on consecutive measurements of cardiac troponins using the 99th percentile of the respective assay as cutoff. The new ESC guidelines alternatively offer rapid 1 h algorithms with lower cutoffs than the 99th percentile for rule-out of non-ST-elevation myocardial infarction. We aimed to compare a recently introduced 1 h algorithm based on a high-sensitivity cardiac troponin I (hs-TnI) cutoff of 6 ng/L at 0 h and 1 h to the current standard of care using the 99th percentile (27 ng/L) as cutoff with reference to follow-up events in a large chest pain cohort. Methods: Hs-TnI was measured at three time points (0 h, 1 h and 3 h) in 1625 patients presenting with suspected myocardial infarction to the emergency department of the University-Medical Center Hamburg-Eppendorf. Seventy-five patients with ST-elevation myocardial infarction were excluded from the analysis. All-cause mortality, cardiac death, acute myocardial infarction, revascularization and cardiac rehospitalization after 12 months were assessed. Results: Patients ruled out by the 1 h algorithm showed significantly less cardiac rehospitalizations (12.84% vs. 17.66%; p < 0.001), and overall mortality (1.30% vs 3.46%, p < 0.001) compared to using the 99th percentile as cutoff. The majority of deaths were caused by non-cardiac reasons. Cardiac deaths were rare using the 1 h algorithm (0.21%). Conclusion: The commonly used 99th percentile as cutoff neglects patients with a high risk in the setting of acute chest pain. (C) 2016 Elsevier Ireland Ltd. All rights reserved.