Title: Accelerated cardiovascular magnetic resonance in coronary artery disease
Funder: Department of Health and Social Care

Abstract: Background Coronary artery disease (CAD) is the leading cause of death and disability in the UK. In patients with suspected angina, major guidelines recommend the use of non-invasive diagnostic imaging. Although the NICE 2016 stable chest pain guidelines recommend computed tomography coronary angiography (CTCA) as the first-line investigation in patients with new onset angina, it is acknowledged that CTCA may be unsuitable in some subjects, and a role remains for alternative functional imaging techniques. Cardiovascular magnetic resonance (CMR) is a safe and accurate imaging modality whose diagnostic performance surpasses that of alternative functional imaging techniques. Despite the recent expansion of CMR services in the UK, capacity has been insufficient to meet increasing demand. Therefore, there is a strong impetus to improve the time efficiency of CMR imaging protocols for the assessment of CAD. Recent technological innovations in CMR theoretically enable shorter CMR examination times (15-20 minutes versus 45-50 minutes for a standard scan) together with improved patient comfort. Whole-heart cine and scar imaging can be performed free-breathing (within 2 minutes for each modality), more rapidly than with standard CMR imaging (where each component takes 8-10 minutes, involving multiple breath-holds). Quantitative perfusion assessment has the potential to improve objectivity and accuracy compared with standard, qualitative evaluation. However, it is important to establish whether the accelerated scan combining these techniques achieves non-inferior diagnostic accuracy when compared with standard CMR imaging. Aims and objectives: to determine, in patients with suspected coronary artery disease, the diagnostic accuracy of an accelerated cardiovascular magnetic resonance (CMR) protocol (15-20 minutes) to determine whether the accelerated CMR protocol achieves non-inferior diagnostic accuracy when compared with a standard CMR scan (45-50 minutes) Methods The lead investigator is the recipient of an NIHR Clinician Scientist award, funding a single-centre diagnostic accuracy study comparing CMR versus CTCA (with fractional flow reserve &ndash; FFRCT) for identifying significant CAD. This study involves 300 patients with suspected angina referred for invasive coronary angiography. Study participants will be invited to take part in a substudy involving an additional accelerated CMR scan. A total of 167 patients will undergo both accelerated and standard CMR scans, enabling a head-to-head comparison of diagnostic performance (diagnostic accuracy, sensitivity and specificity) for identifying functionally significant coronary disease (as defined by fractional flow reserve Timelines for delivery: Study setup - 6 months Recruitment &ndash; 18 months Analysis and reporting &ndash; 6 months Future grant preparation &ndash; 6 months Anticipated impact and dissemination If non-inferior diagnostic accuracy and superior cost effectiveness can be demonstrated for the accelerated protocol, this result will impact clinical practice and future NICE guidance. If the accelerated scan achieves comparable diagnostic accuracy, its adoption within the NHS would enable twice as many patients to be scanned, improving time efficiency and cost-effectiveness, as well as patient comfort and accessibility to CMR. The latest NICE guidelines have based the recommendation of CTCA on cost-effectiveness, but a dramatically faster and cheaper CMR scan could potentially alter the balance in favour of CMR.

Lay abstract: Aim To assess whether a faster and less expensive test can accurately diagnose narrowed heart arteries in patients with chest pain suspected of having heart disease. Background Angina is a condition that causes chest pain due narrowed heart arteries, reducing blood supply to the heart muscle. It affects about 2 million people in the UK. Good treatments are available but we first need to identify who has a problem. Many patients with angina undergo a type of internal X-ray, which involves inserting a small plastic tube into a person s blood vessel. This is called coronary angiography . It is expensive, unpleasant, uses radiation and can go wrong. Imaging scans which take pictures of the heart are safer and more comfortable. One type of scan, Magnetic Resonance Imaging (MRI) is very good at detecting angina but takes around 45-50 minutes and is relatively expensive. Using recent technological advances, we have devised a &ldquo;faster&rdquo;, more comfortable scan, which takes 15-20 minutes. Before the new scan can be recommended, we need to test if it is as accurate as the longer one. Design and methods We will invite 167 people to have both the &ldquo;fast&rdquo; scan and the standard scan, to compare them and see if the &quot;fast&quot; scan is as accurate. We have another project already underway exploring different types of scans in 300 people who have come to hospital with chest pain and need coronary angiography as part of their routine care. We will invite these patients to have the extra, fast scan. Patient/public involvement We will work with patients representatives from the NIHR Leicester Biomedical Research Centre throughout the project. They have helped us design this study and we explored wider patient opinions with a survey. Three Research Champions with relevant life experience will join our Study Steering Group as patient advocates and collaborate on the running of the study. We hope that the Research Champions will play a key role in promoting the study. Expected value of results If the &quot;fast&quot; scan is as accurate as the standard scan, its adoption within the NHS would enable twice as many patients to be scanned in the same time as a standard scan. This will improve efficiency, patient comfort and access to MRI, as well as reducing costs.

Research activity codes: 4.2 EVALUATION OF MARKERS AND TECHNOLOGIES
Health categories: CARDIOVASCULAR