Value of Cardiac Troponin I Cutoff Concentrations below the 99th Percentile for Clinical Decision-Making
Open Access
- 1 January 2009
- journal article
- research article
- Published by Oxford University Press (OUP) in Clinical Chemistry
- Vol. 55 (1), 85-92
- https://doi.org/10.1373/clinchem.2007.101683
Abstract
Background: The aim of this study was to evaluate factors influencing the 99th percentile for cardiac troponin I (cTnI) when this cutoff value is established on a highly sensitive assay, and to compare the value of this cutoff to that of lower cutoffs in the prognostic assessment of patients with coronary artery disease. Methods: We used the recently refined Access AccuTnI assay (Beckman-Coulter) to assess the distribution of cTnI results in a community population of elderly individuals [PIVUS (Prospective Study of the Vasculature in Uppsala Seniors) study; n = 1005]. The utility of predefined cTnI cutoffs for risk stratification was then evaluated in 952 patients from the FRISC II (FRagmin and Fast Revascularization during InStability in Coronary artery disease) study at 6 months after these patients had suffered acute coronary syndrome. Results: Selection of assay results from a subcohort of PIVUS participants without cardiovascular disease resulted in a decrease of the 99th percentile from 0.044 μg/L to 0.028 μg/L. Men had higher rates of cTnI elevation with respect to the tested thresholds. Whereas the 99th percentile cutoff was not found to be a useful prognostic indicator for 5-year mortality, both the 90th percentile (hazard ratio 3.1; 95% CI 1.9–5.1) and the 75th percentile (hazard ratio 2.8; 95% CI 1.7–4.7) provided useful prognostic information. Sex-specific cutoffs did not improve risk prediction. Conclusions: The 99th percentile of cTnI depends highly on the characteristics of the reference population from which it is determined. This dependence on the reference population may affect the appropriateness of clinical conclusions based on this threshold. However, cTnI cutoffs below the 99th percentile seem to provide better prognostic discrimination in stabilized acute coronary syndrome patients and therefore may be preferable for risk stratification.Keywords
Funding Information
- AstraZeneca
This publication has 25 references indexed in Scilit:
- Universal Definition of Myocardial InfarctionCirculation, 2007
- Persistent Cardiac Troponin I Elevation in Stabilized Patients After an Episode of Acute Coronary Syndrome Predicts Long-Term MortalityCirculation, 2007
- Usefulness of Detectable Levels of Troponin, Below the 99th Percentile of the Normal Range, as a Clue to the Presence of Underlying Coronary Artery DiseaseThe American Journal of Cardiology, 2007
- Guidelines for the diagnosis and treatment of non-ST-segment elevation acute coronary syndromes: The Task Force for the Diagnosis and Treatment of Non-ST-Segment Elevation Acute Coronary Syndromes of the European Society of CardiologyEuropean Heart Journal, 2007
- A Model for Troponin I as a Quantitative Predictor of In-Hospital MortalityJournal of the American College of Cardiology, 2006
- Development and Preliminary Clinical Validation of a High Sensitivity Assay for Cardiac Troponin Using a Capillary Flow (Single Molecule) Fluorescence DetectorClinical Chemistry, 2006
- 5-year outcomes in the FRISC-II randomised trial of an invasive versus a non-invasive strategy in non-ST-elevation acute coronary syndrome: a follow-up studyThe Lancet, 2006
- Troponin I as a Predictor of Coronary Heart Disease and Mortality in 70-Year-Old MenCirculation, 2006
- A Comparison of Three Different Methods to Evaluate Endothelium-Dependent Vasodilation in the ElderlyArteriosclerosis, Thrombosis, and Vascular Biology, 2005
- Invasive compared with non-invasive treatment in unstable coronary-artery disease: FRISC II prospective randomised multicentre studyThe Lancet, 1999