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Performance of highly sensitive cardiac troponin T assay to detect ischaemia at PET-CT in low-risk patients with acute coronary syndrome: a prospective observational study

Abstract

Background Highly sensitive troponin T (hs-TnT) assay has improved clinical decision-making for patients admitted with chest pain. However, this assay’s performance in detecting myocardial ischaemia in a lowrisk population has been poorly documented.

Purpose To assess hs-TnT assay’s performance to detect myocardial ischaemia at positron emission tomography/CT (PET-CT) in low-risk patients admitted with chest pain.

Methods Patients admitted for chest pain with a nonconclusive ECG and negative standard cardiac troponin T results at admission and after 6 hours were prospectively enrolled. Their hs-TnT samples were at T0, T2 and T6. Physicians were blinded to hs-TnT results. All patients underwent a PET-CT at rest and during adenosine-induced stress. All patients with a positive PET-CT result underwent a coronary angiography.

Results Forty-eight patients were included. Six had ischaemia at PET-CT. All of them had ≥1 significant stenosis at coronary angiography. Areas under the curve (95% CI) for predicting significant ischaemia at PET-CT using hs-TnT were 0.764 (0.515 to 1.000) at T0, 0.812(0.616 to 1.000) at T2 and 0.813(0.638 to 0.989) at T6. The receiver operating characteristicbased optimal cut-off value for hs-TnT at T0, T2 and T6 needed to exclude significant ischaemia at PET-CT was <4 ng/L. Using this value, sensitivity, specificity, positive and negative predictive values of hs-TnT to predict significant ischaemia were 83%/38%/16%/94% at T0, 100%/40%/19%/100% at T2 and 100%/43%/20%/100% at T6, respectively.

Conclusions Our findings suggest that in low-risk patients, using the hs-TnT assay with a cut-off value of 4 ng/L demonstrates excellent negative predictive value to exclude myocardial ischaemia detection at PET-CT, at the expense of weak specificity and positive predictive value.

Trial registration number ClinicalTrials.gov Identifier: NCT01374607.

  • troponin
  • acute coronary syndrome
  • positron emission tomography
  • ischemia

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Footnotes

  • Contributors BM and SF contributed to the conception of the study, to acquisition and analysis of the data, performed analysis and prepared the draft of the manuscript. MT gave the design of the study, gathered and managed the data. JOP, PAM and VD gathered the data, gave critical view to the design and the draft of the manuscript. NL and FR participated in analysis and gathering of the data. CT, J-FI and DK gathered the data, performed analysis and participated in preparation of the manuscript. OB, DB and SL performed laboratory analyses and data management. EE, OH and OM participated in the design of the study, approved all analyses and gave critical overview to the manuscript.

  • Competing interests None declared.

  • Patient consent Informed consent approved by the local ethical committe was obtained from all individual participants included in the study.

  • Ethics approval Ethical Commitee CHUV Lausanne.

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Data sharing statement No additional data available.

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