Troponin in Acute Chest Pain to Risk Stratify and Guide EffecTive Use of Computed Tomography Coronary Angiography

Most patients presenting to hospital with symptoms of a heart attack are sent home without further tests once a heart attack has been ruled out. Current strategies to assess patients with a suspected heart attack involve blood tests to measure troponin, a protein released into the bloodstream when the heart muscle is damaged. Despite having had a heart attack ruled-out, some patients have unrecognised heart disease and are at risk of having a heart attack in the future. However, clinicians do not know what is the best approach to identify and treat these patients. This study will use a heart scan known as computed tomography coronary angiogram (CTCA) to look for unrecognised heart disease in patients who have had a heart attack ruled out. In an earlier study, the Investigators performed this scan in patients referred to the outpatient cardiology clinic with stable chest pain and found that this improved the diagnosis of heart disease, leading to improvement in patient care that prevented future heart attacks. Previous research from the Investigators has also found that troponin levels below those used to diagnose a heart attack may help to identify those who are at greater risk of having a heart attack in the future. The aim of this study is to find out if patients with these low levels of troponin, where a heart attack has been ruled out, will benefit from CTCA to look for unrecognised coronary heart disease.

Inclusion Criteria: * Presenting to hospital with symptoms of suspected acute coronary syndrome * Age 18 years and over * Maximum high-sensitivity cardiac troponin concentration between 5ng/L and the 99th percentile Exclusion Criteria: * Diagnosis of myocardial infarction during index presentation * Clear alternative diagnosis or participant requires further inpatient clinical assessment * Recent CTCA or invasive coronary angiogram (within 1 year) * Patient inability to undergo CT scanning, e.g. due to severe renal failure (estimated glomerular filtration rate \<30 mL/min) or major allergy to iodinated contrast media * Current pregnancy or breast feeding * Inability to give informed consent * Further investigation for coronary artery disease would not be in the patient's interest, e.g. due to limited life expectancy, quality of life or functional status * Previous randomisation into the trial