Patient selection for high sensitivity cardiac troponin testing and diagnosis of myocardial infarction: prospective cohort studyBMJ 2017; 359 doi: https://doi.org/10.1136/bmj.j4788 (Published 07 November 2017) Cite this as: BMJ 2017;359:j4788
- Anoop S V Shah, clinical lecturer in cardiology1,
- Yader Sandoval, consultant cardiologist2,
- Ala Noaman, foundation doctor1,
- Anne Sexter, statistician3,
- Amar Vaswani, foundation doctor1,
- Stephen W Smith, professor of emergency medicine4,
- Mathew Gibbins, biomedical scientist1,
- Megan Griffiths, foundation doctor1,
- Andrew R Chapman, clinical research fellow1,
- Fiona E Strachan, clinical research manager1,
- Atul Anand, clinical research fellow1,
- Martin A Denvir, consultant cardiologist,1,
- Philip D Adamson, senior research fellow in cardiology1,
- Michelle S D’Souza, medical student1,
- Alasdair J Gray, consultant and honorary professor of emergency medicine5,
- David A McAllister, senior clinical lecturer in public health6,
- David E Newby, professor of cardiology1,
- Fred S Apple, professor of laboratory medicine and pathology7,
- Nicholas L Mills, professor of cardiology1
- 1BHF Centre for Cardiovascular Science, University of Edinburgh, Edinburgh EH16 4SB, UK
- 2Division of Cardiology, Hennepin County Medical Center and Minneapolis Heart Institute, Abbott Northwestern Hospital, Minneapolis, MN, USA
- 3Chronic Disease Research Group of Minneapolis Medical Research Foundation, Hennepin County Medical Center and University of Minnesota, Minneapolis, MN, USA
- 4Department of Emergency Medicine, Hennepin County Medical Center and University of Minnesota, Minneapolis, Minnesota, USA.
- 5Emergency Medicine Research Group Edinburgh (EMeRGE) and Department of Emergency Medicine, Royal Infirmary of Edinburgh, Edinburgh, UK
- 6Institute of Health and Wellbeing, University of Glasgow, Glasgow, UK
- 7Department of Laboratory Medicine and Pathology, Hennepin County Medical Center and University of Minnesota, Minneapolis, MN, USA
- Correspondence to: A Shah
- Accepted 11 October 2017
Objective To evaluate how selection of patients for high sensitivity cardiac troponin testing affects the diagnosis of myocardial infarction across different healthcare settings.
Design Prospective study of three independent consecutive patient populations presenting to emergency departments.
Setting Secondary and tertiary care hospitals in the United Kingdom and United States.
Participants High sensitivity cardiac troponin I concentrations were measured in 8500 consecutive patients presenting to emergency departments: unselected patients in the UK (n=1054) and two selected populations of patients in whom troponin testing was requested by the attending clinician in the UK (n=5815) and the US (n=1631). The final diagnosis of type 1 or type 2 myocardial infarction or myocardial injury was independently adjudicated.
Main outcome measures Positive predictive value of an elevated cardiac troponin concentration for a diagnosis of type 1 myocardial infarction.
Results Cardiac troponin concentrations were elevated in 13.7% (144/1054) of unselected patients, with a prevalence of 1.6% (17/1054) for type 1 myocardial infarction and a positive predictive value of 11.8% (95% confidence interval 7.0% to 18.2%). In selected patients, in whom troponin testing was guided by the attending clinician, the prevalence and positive predictive value were 14.5% (843/5815) and 59.7% (57.0% to 62.2%) in the UK and 4.2% (68/1631) and 16.4% (13.0% to 20.3%) in the US. Across both selected patient populations, the positive predictive value was highest in patients with chest pain, with ischaemia on the electrocardiogram, and with a history of ischaemic heart disease.
Conclusions When high sensitivity cardiac troponin testing is performed widely or without previous clinical assessment, elevated troponin concentrations are common and predominantly reflect myocardial injury rather than myocardial infarction. These observations highlight how selection of patients for cardiac troponin testing varies across healthcare settings and markedly influences the positive predictive value for a diagnosis of myocardial infarction.
Contributors: ASVS and NLM designed the study and carried out the initial acquisition, analysis, or interpretation of data. All authors were involved in drafting and revising the manuscript and have given final approval of the version to be published. ASVS is the guarantor.
Funding: This research was funded by the British Heart Foundation (SP/12/10/29922 and PG/15/51/31596). NLM and DEN are supported by the Butler Senior Clinical Research Fellowship (FS/16/14/32023) and John Wheatley Chair (CH/09/002) awards respectively from the British Heart Foundation. DAM is supported by the Wellcome Trust (Intermediate Clinical Fellowship 201492/Z/16/Z). Abbott Laboratories provided high sensitivity cardiac troponin I assay reagents, calibrators, and controls.
Competing interests: All authors have completed the ICMJE uniform disclosure form at www.icmje.org/coi_disclosure.pdf (available on request from the corresponding author) and declare: support for the submitted work as described above; NLM has acted as a consultant for Abbott Diagnostics, Roche Diagnostics, and Singulex; ASVS has acted as a consultant for Abbott Diagnostics; AC has received speaker fees from Abbott Diagnostics; FSA has acted as a consultant to Metanomics Healthcare, an advisor to Instrumentation Laboratory and Abbott Diagnostics, and on the Board of Directors of HyTest Ltd; YS has acted as an advisor for Roche Diagnostics; no other relationships or activities that could appear to have influenced the submitted work.
Ethical approval: All three patient populations in this study included consecutive patients with approval from the regional or national research ethics committee and in accordance with the Declaration of Helsinki. For the unselected patient population, approval to obtain plasma surplus to clinical requirement was granted by the National Research Scotland BioResource and Tissue Governance Unit. For the selected patient populations in the UK and US, approval was granted by the Scotland A Regional Ethics Committee and the Human Subjects Research Committee of Hennepin County Medical Center respectively.
Data sharing: Patient level data and statistical code will be available from the corresponding author following publication of the primary study (HighSTEACS: NCT01852123). Participants’ consent to share data was not obtained, but the presented data are anonymised and risk of identification is low.
Transparency declaration: The lead author (the manuscript’s guarantor) affirms that the manuscript is an honest, accurate, and transparent account of the study being reported; that no important aspects of the study have been omitted; and that any discrepancies from the study as planned (and, if relevant, registered) have been explained.
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