Association of High-Sensitivity Cardiac Troponin I Concentration With Cardiac Outcomes in Patients With Suspected Acute Coronary Syndrome

Abstract

IMPORTANCE High-sensitivity cardiac troponin I testing is widely used to evaluate patients with suspected acute coronary syndrome. A cardiac troponin concentration of less than 5 ng/L identifies patients at presentation as low risk, but the optimal threshold is uncertain. OBJECTIVE To evaluate the performance of a cardiac troponin I threshold of 5 ng/L at presentation as a risk stratification tool in patients with suspected acute coronary syndrome.

Clinical chemistry score versus high-sensitivity cardiac troponin I and T tests alone to identify patients at low or high risk for myocardial infarction or death at presentation to the emergency department

“…For identifying low-risk patients who may be suitable for discharge, many different approaches have been proposed, with the simplest being a low or undetectable hs-cTn concentration. 2,3 Despite the ease of these approaches, using hs-cTn alone has not reliably achieved a sensitivity greater than 99.0% to safely rule out MI and discharge patients presenting to the emergency department in large populations. 2,3 At the other extreme, for rule in of MI and identifying patients at high risk who require hospital admission, besides the use of electrocardiograms, algorithms that have used hs-cTn tests alone use cut-offs that are several-fold higher than the published 99th percentiles.…”

“…2,3 Despite the ease of these approaches, using hs-cTn alone has not reliably achieved a sensitivity greater than 99.0% to safely rule out MI and discharge patients presenting to the emergency department in large populations. 2,3 At the other extreme, for rule in of MI and identifying patients at high risk who require hospital admission, besides the use of electrocardiograms, algorithms that have used hs-cTn tests alone use cut-offs that are several-fold higher than the published 99th percentiles. 35 The required specificity or PPV for algorithms to identify patients at high risk have not undergone the same methodological approach as the sensitivity estimate.…”

“…We performed receiver operating characteristic (ROC) curve analysis for the CCS algorithms for each emergency department population, including sex-specific analysis that assessed the CCS algorithms for the primary outcome, with comparison to hs-cTn concentration alone (low risk: hs-cTnI < 5 ng/L or hs-cTnT < 6 ng/L; high risk [overall 99th percentiles]: hs-cTnI > 26 ng/L or hs-cTnT > 14 ng/L) 3,30,33 in the overall emergency department population. We generated the ROC curves based on data without smoothing, and we calculated the area under the ROC curves (AUC) correspondingly.…”

“…3 However, as hs-cTn assays become even more analytically sensitive and precise at lower concentrations, it will be expected that all individuals will have a detectable concentration of cardiac troponin, which would make this cut-off obsolete. Second, we elected to assess outcomes only to 30 days after presentation to the emergency department.…”

More evidence for high-sensitivity troponin assays

“…This topic is addressed in the present manuscript by Chapman et al 3. The authors from the High-STEACS research group investigated the diagnostic performance of a novel hs-TnI assay, which is run on the Siemens Atellica system.…”