Early kinetic profiles of troponin I and T measured by high-sensitivity assays in patients with myocardial infarction

• Published in: Clinica chimica acta 2020-06, Vol.505, p.15-25
• Main Authors: Pickering, John W., Young, Joanna M., George, Peter M., Pemberton, Christopher J., Watson, Antony, Aldous, Sally J., Verryt, Toby, Troughton, Richard W., Richards, A. Mark, Apple, Fred S., Than, Martin P.
• Format: Article
• Language: English
• Subjects: Acute myocardial infarction; Aged; Biomarkers; Clinical Decision-Making; Emergency department; Emergency room; Female; High-sensitivity cardiac troponin; Humans; Kinetics; Limit of Detection; Male; Middle Aged; Myocardial Infarction - diagnosis; Myocardial Infarction - metabolism; Non-ST Elevated Myocardial Infarction - metabolism; Prospective Studies; Risk Assessment; Treatment Outcome; Troponin I - analysis; Troponin I - metabolism; Troponin T - analysis; Troponin T - metabolism
• ISSN: 0009-8981; 1873-3492
• DOI: 10.1016/j.cca.2020.02.009

•In NSTEMI patients there was considerable variation in the kinetic profiles of cTn concentrations.•cTnI concentrations increased at a much more rapid rate than cTnT concentrations.•Concentrations of 33% of patients took 3 h from symptom onset to exceed rule-out thresholds. The early concentration kinetic profiles of cardiac troponin in patients with non-ST-elevated myocardial infarction (NSTEMI) measured by high-sensitivity cardiac troponin I (hs-cTnI) and T (hs-cTnT) assays have not been described. In intermediate-to-high-risk of NSTEMI patients we measured serial cTn concentrations on ED arrival, at 1, 2, 3, 6–12, 24 and 48-hours with hs-cTnI and hs-cTnT assays. Log-normal curves were fitted to concentrations from time from symptom onset, and the time to rule-out decision thresholds estimated (hs-cTnI: 2 ng/L and 5 ng/L; hs-cTnT: 5 ng/L). Among 164 patients there were 58 NSTEMI. The hs-cTnI to hs-cTnT ratio increased linearly over the first 6–12 h following symptom onset. The estimated times from symptom onset to the 2 ng/L and 5 ng/L thresholds for hs-cTnI were 1.8 (0.1–3.1) and 1.9 (1.1–3.5) hours, and to the 5 ng/L threshold for hs-cTnT 1.9 (1.1–3.8) hours. The estimated time to exceed 5 ng/L was ≥3 hours in 32.6% (95%CI: 20.0% to 48.1%) cases for hs-cTnI and 33.3% (19.6% to 50.0%) for hs-cTnT. cTnI concentrations increased at a much more rapid rate than cTnT concentrations in patients with NSTEMI. Concentrations of a high proportion of patients took longer than 3 hours from symptom onset to exceed the 5 ng/L rule-out decision threshold.