The clinical utility of cardiac magnetic resonance imaging in patients with angina but no obstructive coronary disease (CorCMR): A diagnostic study and nested randomised trial

Background: More than 247,000 coronary angiograms are performed in the NHS annually, and >1 in 3 patients have no evidence of obstructive coronary artery disease (NOCAD). The diagnosis and onward management may be uncertain and prognosis is affected. Hypothesis: Microvascular angina is common in patients with NOCAD and a CMR-strategy improves outcomes.

Design: A diagnostic imaging study and nested, randomised, controlled, strategy trial.

Inclusion: Consecutive patients (n=280; intention-to-treat) with angina and NOCAD (0.80) after invasive coronary angiography (ICA) will be invited to undergo cardiac magnetic resonance (CMR) with stress perfusion; 1:1 randomisation (CMR-disclosed/guided vs. CMR-blinded. Exclusions: 1) Alternative causes of angina (e.g. aortic stenosis, cardiomyopathy), 2) Contraindications to CMR.

Outcomes: Primary: Reclassification of the initial diagnosis after CMR. Secondary: Health status/quality-of-life; NHS resources. Blinded follow-up: minimum 6-months (last patient-in), maximum 24 months (first patient-in). Value: Results relevant to patients, clinicians and the NHS.