MedicalResearch.com Interview with:
Dr Andrew R. Chapman
BHF Clinical Research Fellow
University of Edinburgh
Chancellors Building
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.
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