Accelerated cardiovascular magnetic resonance for the detection of coronary artery disease – a randomised controlled trial (ACCELERATE-CMR)

INTRODUCTION Cardiovascular magnetic resonance (CMR) is a non-invasive scan for diagnosing coronary artery disease (CAD). RESEARCH QUESTION (1) Does a newer, faster CMR scan perform clinically as well as a standard scan, and (2) is it preferred by people with suspected CAD? BACKGROUND TO THE RESEARCH CAD is the leading cause of death in the UK, disproportionately affecting minority ethnic groups and those in areas of high deprivation. Good treatments exist but first require accurate diagnosis. Invasive coronary angiography (ICA) is the diagnostic gold standard but is hampered by cost and risk of serious complications (1% risk of death/stroke/cardiac damage). Hence, guidelines recommend non-invasive imaging as a “gatekeeper” to refine diagnosis and appropriately select patients for ICA and revascularisation. CMR offers excellent diagnostic accuracy. However, in the UK, limited capacity restricts widespread use. One solution to reduce waiting lists is installing more scanners. Another is to develop faster, focused protocols to improve the efficiency of existing scanners. Using recent technical advances, we have devised a faster, more comfortable stress CMR scan: it takes 15-20 minutes instead of the usual 45-50 minutes. This method uses existing NHS scanners but with newer software. The lead investigator has received NIHR Clinician Scientist and Research for Patient Benefit awards to evaluate this new approach. This work (n=149) showed that the new scan is accurate compared with the gold standard (ICA), and shows excellent agreement with the longer, standard CMR scan. It is also more comfortable for patients. OBJECTIVES To determine whether, compared with a standard CMR scan, an accelerated CMR scan: 1) Is equally efficacious in terms of its clinical performance AND 2) Is preferred by patients METHODS We propose a prospective multi-centre, randomised trial of 2022 people with suspected CAD referred for clinical CMR. Participants will be randomised (1:1) to standard or accelerated CMR. Inclusion criteria are: 1) symptoms of chest pain/angina equivalent OR 2) known/suspected heart failure referred for diagnosis of CAD Exclusion criteria: standard exclusions for clinical stress CMR. The primary endpoint is a composite of unnecessary ICA (defined as no revascularisation or invasive fractional flow reserve =0.80), unplanned revascularisation (within 12 months) or additional non-invasive testing (within 12 months). Patient acceptance will also be assessed. The study is powered to show that accelerated CMR is non-inferior to standard CMR. Data will also be collected for future health economic analysis. TIMELINES FOR DELIVERY Study setup - 6m; recruitment - 3y; follow up -12m; analysis/reporting - 6m. ANTICIPATED IMPACT AND DISSEMINATION This trial has the potential for substantial clinical impact if efficacy is demonstrated. Adoption of accelerated CMR within the NHS will improve both time efficiency and cost effectiveness, enabling twice as many patients to receive CMR. Improved accessibility to accurate diagnostics will enable a step-change in management for patients who may otherwise have received inferior tests, and thus suboptimal care. Our findings will be shared with patients, clinicians and NHS commissioners, being published in leading cardiovascular journals and presented at international conferences. We will engage with our patient representatives to publicise the results, including via social and mainstream media.