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 o 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 lview 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% Cl, 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% Cl, 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% Cl, 0.12-0.34, P < .001); CMR group vs the MPS group, 1.27(95% CI, 0.792.03, P =.32). Positive angiography proportions were 12.1% (95% Cl, 8.2%-16.9%; 29/240 patients) for the NICE guidelines group, 9.8% (95% Cl, 7.3%12.8%; 47/481 patients) for the CMR group, and 8.7% (95% Cl, 6.4%-11.6%; 42/481 patients) for the MPS group. A MACE was reported at a minimum of 12 months in 1.7% of patients in the NICE guidelines group, 2.5% in the CMR group, and 2.5% in the MPS group (adjusted hazard ratios: CMR group vs NICE guidelines group, 1.37 [95% Cl, 0.52-3.57]; CMR group vs MPS group, 0.95 [95% CI, 0.46-1.95]). CONCLUSIONS AND RELEVANCE In patients with suspected angina, investigation by CMR resulted in a lower probability of unnecessary angiography within 12 months than NICE guideline-directed care, with no statistically significant difference between CMR and MPS strategies. There were no statistically significant differences in MACE rates.