Effect of Care Guided by Cardiovascular Magnetic Resonance, Myocardial Perfusion Scintigraphy, or NICE Guidelines on Subsequent Unnecessary Angiography Rates:The CE-MARC 2 Randomized Clinical Trial

IMPORTANCE: Among patients with suspected coronary heart disease (CHD), rates of invasive angiography are considered too high. OBJECTIVE: To test the hypothesis that among patients with suspected CHD, cardiovascular magnetic resonance (CMR)-guided care is superior to National Institute for Health and Care Excellence (NICE) guidelines-directed care and myocardial perfusion scintigraphy (MPS)-guided care in reducing unnecessary angiography. DESIGN, SETTING, AND PARTICIPANTS: Multicenter, 3-parallel group, randomized clinical trial using a pragmatic comparative effectiveness design. From 6 UK hospitals, 1202 symptomatic patients with suspected CHD and a CHD pretest likelihood of 10% to 90% were recruited. First randomization was November 23, 2012; last 12-month follow-up was March 12, 2016. INTERVENTIONS: Patients were randomly assigned (240:481:481) to management according to UK NICE guidelines or to guided care based on the results of CMR or MPS testing. MAIN OUTCOMES AND MEASURES: The primary end point was protocol-defined unnecessary coronary angiography (normal fractional flow reserve >0.8 or quantitative coronary angiography [QCA] showing no percentage diameter stenosis ≥70% in 1 view or ≥50% in 2 orthogonal views in all coronary vessels ≥2.5 mm diameter) within 12 months. Secondary end points included positive angiography, major adverse cardiovascular events (MACEs), and procedural complications. RESULTS: Among 1202 symptomatic patients (mean age, 56.3 years [SD, 9.0]; women, 564 [46.9%] ; mean CHD pretest likelihood, 49.5% [SD, 23.8%]), number of patients with invasive coronary angiography after 12 months was 102 in the NICE guidelines group (42.5% [95% CI, 36.2%-49.0%])], 85 in the CMR group (17.7% [95% CI, 14.4%-21.4%]); and 78 in the MPS group (16.2% [95% CI, 13.0%-19.8%]). Study-defined unnecessary angiography occurred in 69 (28.8%) in the NICE guidelines group, 36 (7.5%) in the CMR group, and 34 (7.1%) in the MPS group; adjusted odds ratio of unnecessary angiography: CMR group vs NICE guidelines group, 0.21 (95% CI, 0.12-0.34, P