High-sensitivity cardiac troponin I (hs-cTnI) levels can be used to identify patients at low and high risk for acute myocardial infarction (AMI), according to study results published in the Journal of the American College of Cardiology.
The results indicated that a threshold of hs-cTnI <5 ng/L identifies low-risk patients whereas hs-cTnI ≥120 ng/L identifies patients at high risk.
The study included patients with suspected AMI from 29 US sites (N=2212). The researchers measured hs-cTnI using the Atellica® IM TnIH and ADVIA Centaur® TNIH (Siemens Healthineers, Munich, Germany) assays. In order to identify low-risk patients, the researchers examined baseline hs-cTnI concentrations for sensitivities and negative predictive values (NPVs) for AMI and myocardial infarction or death at 30 days. To identify high-risk patients, they evaluated positive predictive values and specificities for AMI.
Of 2212 patients, 12% experienced AMI.
For AMI or death at 30 days, the limits of detection or quantitation produced highly accurate sensitivities (range, 98.6% to 99.6%) and NPVs (range, 99.5% to 99.8%).
When using an optimized threshold of <5 ng/L, the researchers could identify nearly half of all participants as low-risk, with sensitivities of 98.6% (95% CI, 97.2%-100%) and NPVs of 99.6% (95% CI, 99.2%-100%) for AMI or death at 30 days across both assays.
The results indicated that hs-cTnl ≥120 ng/L results in positive predictive values for AMI of ≥70% in high-risk patients.
“[A] single measurement at presentation can also facilitate the triage of patients at high risk, with concentrations ≥120 ng/[L] identifying a subset of patients at high risk for acute MI at presentation in whom prompt evaluation and/or management is needed in the appropriate clinical context,” the researchers wrote.
Sandoval Y, Nowak R, deFilippi C, et al. Myocardial infarction risk stratification with a single measurement of high-sensitivity troponin I. J Am Coll Cardiol. 2019;74(3):271-282.