MedicalResearch.com Interview with:
Dr Andrew R. Chapman
BHF Clinical Research Fellow
University of Edinburgh
MedicalResearch.com: What is the background for this study? What are the main findings?
Response: High-sensitivity cardiac troponin tests allow accurate measurement of cardiac troponin in the bloodstream. Currently, guidelines recommend we evaluate patients with suspected myocardial infarction using these tests, by looking for levels which are above the upper reference limit (99th centile). These troponin measurements are taken on arrival, and often repeated after admission to hospital up to six hours later. When levels are below this limit, the diagnosis of myocardial infarction is ruled out. However, using such a high limit in patients on arrival to hospital may not be safe, as lower risk stratification thresholds has been shown to reduce missed events, and in these patients admission to hospital for repeat testing may not be necessary. However, there is no consensus as to the optimal threshold for use in practice.
In a worldwide study of 23,000 patients from 9 countries, we have shown when high-sensitivity cardiac troponin I concentrations are below a risk stratification threshold of 5 ng/L at presentation, patients are at extremely low risk of myocardial infarction or cardiac death at 30 days, with fewer than 1 in 200 patients missed. Importantly, this threshold identifies almost 50% of all patients as low risk after a single blood test. As admission or observation of these patients is estimated to cost as much as $11 billion per year in the United States, this strategy has major potential to improve the efficiency of our practice.
MedicalResearch.com: What should clinicians and patients take away from your report?
Response: Risk stratification thresholds are safe and may reduce the need for admission to hospital in up to 50% of all patients presenting with chest pain and suspected acute coronary syndrome. We believe this threshold, when applied in conjunction with a non-ischaemic electrocardiogram, has major potential to improve the safety and efficiency of our practice. As we demonstrate this strategy is safe across a variety of healthcare settings with variation in practice, we believe our findings ar generalzable, and that international guidelines should change to reflect the role of risk stratification thresholds in practice.
MedicalResearch.com: What recommendations do you have for future research as a result of this study?
Response: The assay under investigation (High-Sensitivity Cardiac Troponin I, Abbott Diagnostics) has been available for commercial use in Europe, Australasia and Canada since 2013, and is pending FDA approval for use in the United States. As all studies to evaluate this test to date are observational, implementation studies are required to assess the real world clinical and cost effectiveness. We are therefore conducting a consecutive patient randomized controlled trial across 30,000 patients in Scotland (clinicaltrials.gov NCT:03005158) and aim to report our findings in 2018.
Disclosures: Dr Chapman receives research grants from the British Heart Foundation (BHF), and has previously received speaker fees for Abbott Diagnostics and AstraZeneca.
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Citation: AHA abstract 2017 and JAMA publication:
Chapman AR, Lee KK, McAllister DA, Cullen L, Greenslade JH, Parsonage W, Worster A, Kavsak PA, Blankenberg S, Neumann J, Söerensen NA, Westermann D, Buijs MM, Verdel GJE, Pickering JW, Than MP, Twerenbold R, Badertscher P, Sabti Z, Mueller C, Anand A, Adamson P, Strachan FE, Ferry A, Sandeman D, Gray A, Body R, Keevil B, Carlton E, Greaves K, Korley FK, Metkus TS, Sandoval Y, Apple FS, Newby DE, Shah ASV, Mills NL. Association of High-Sensitivity Cardiac Troponin I Concentration With Cardiac Outcomes in Patients With Suspected Acute Coronary Syndrome. JAMA. Published online November 11, 2017. doi:10.1001/jama.2017.17488
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