Coronary CT angiography for improved assessment of patients with acute chest pain and low-range positive high-sensitivity troponins: study protocol for a prospective, observational, multicentre study (COURSE trial)

Abstract

Introduction: Current evaluation of patients suspected of a non-ST-elevation acute coronary syndrome (NSTE-ACS) involves the use of algorithms that incorporate clinical information, electrocardiogram (ECG) and high-sensitivity cardiac troponins (hs-troponins). While primarily designed to rule out NSTE-ACS safely, these algorithms can also be used for rule in of NSTE-ACS in some patients. Still, in a substantial number of patients, these algorithms do not provide a conclusive work-up. These patients often present with an atypical clinical profile and low-range positive hs-troponin values without a characteristic rise or fall pattern. They represent a heterogeneous group of patients with various underlying conditions; only a fraction (30%-40%) will eventually be diagnosed with a myocardial infarction. Uncertainty exists about the optimal diagnostic strategy and their management depends on the clinical perspective of the treating physician ranging from direct discharge to admission for invasive coronary angiography. Coronary CT angiography (CCTA) is a non-invasive test that has been shown to be safe, fast and reliable in the evaluation of coronary artery disease. In this study, we will determine the usefulness of CCTA in patients with acute chest pain and low-range positive hs-troponin values.

Methods and analysis: A prospective, double-blind, observational, multicentre study conducted in the Netherlands. Patients aged 30-80 years presenting to the emergency department with acute chest pain and a suspicion of NSTE-ACS, a normal or non-diagnostic ECG and low-range positive hs-troponins will be scheduled to undergo CCTA. The primary outcome is the diagnostic accuracy of CCTA for the diagnosis of NSTE-ACS at discharge, in terms of sensitivity and negative predictive value.

Ethics and dissemination: This study was approved by the Medical Research Ethics Committee of Erasmus Medical Center in Rotterdam, the Netherlands (registration number MEC-2017-506). Written informed consent to participate will be obtained from all participants. This study's findings will be published in a peer-reviewed journal.

Trial registration number: ClinicalTrials.gov (NCT03129659).

Keywords: cardiology; cardiovascular imaging; coronary heart disease; myocardial infarction.

Figure 1

Adopted from the European Society of Cardiology 2020 guidelines. Proposed 0-hour/1-hour algorithm for the diagnostic work-up of suspected non-ST-elevation acute coronary syndrome (NSTE-ACS). *Only applicable if chest pain onset >3 hours; ∆, delta. CCTA, coronary CT angiography; CCU, coronary care unit; hs-cTn, high-sensitivity cardiac troponin.

Figure 2

Study design. Observational group refers to patients who do not meet the criteria for either ‘rule-out’ or ‘rule-in’. CCTA, coronary CT angiography; Dx, diagnosis; ICA, invasive coronary angiography; Rx, medication.

Figure 3

Rule-out and rule-in algorithm, adopted from the European Society of Cardiology 2020 guidelines for the diagnostic work-up of non-ST-elevation acute coronary syndrome (NSTE-ACS). ‘0 hour/1 hour’ rule-out and rule-in algorithms using high-sensitivity cardiac troponin (hs-cTn) assays. #=‘0-hour/3-hour’ algorithm is only used as a substitute in cases where the standard ‘0-hour/1-hour’ algorithm is not feasible. 0 hour, 1 hour and 3 hour refer to the time (in hours) from first blood draw. hs-cTnI, high-sensitivity cardiac troponin I; hs-cTnT, high-sensitivity cardiac troponin T; ∆, delta.

Figure 4

Exemplary case showcasing the use of CCTA as a gatekeeper for patients with low-range positive high-sensitivity troponin levels in the emergency department (ED). CAD, coronary artery disease; CCTA, coronary CT angiography; ESC, European Society of Cardiology; hs-TnT, high-sensitivity troponin T; ICA, invasive coronary angiography; LAD, left anterior descending artery; LCX, left circumflex artery; RCA, right coronary artery.