Combined Assessment of Stress Myocardial Perfusion Cardiovascular Magnetic Resonance and Flow Measurement in the Coronary Sinus Improves Prediction of Functionally Significant Coronary Stenosis Determined by Fractional Flow Reserve in Multivessel Disease

BACKGROUND: Recent studies using stress‐rest perfusion cardiovascular magnetic resonance (CMR) demonstrated a close correlation between myocardial ischemia and reduced fractional flow reserve (FFR). However, its diagnostic concordance may be reduced in patients with multivessel disease. We sought to evaluate the concordance of adenosine stress‐rest perfusion CMR for predicting reduced FFR, and to determine the additive value of measuring global coronary flow reserve (CFR) in the coronary sinus in multivessel disease. METHODS AND RESULTS: Ninety‐six patients with angiographic luminal narrowing >50% underwent comprehensive CMR study and FFR measurements in 139 coronary vessels. FFR <0.80 was considered hemodynamically significant. Global CFR was quantified as the ratio of stress‐rest coronary sinus flow measured by phase‐contrast cine CMR. In 25 patients with single‐vessel disease, visual assessment of perfusion CMR yielded high diagnostic concordance for predicting flow‐limiting stenosis, with the area under receiver operating characteristic curve of 0.93 on a per‐patient basis. However, in 71 patients with multivessel disease, perfusion CMR underestimated flow‐limiting stenosis, resulting in the reduced area under receiver operating characteristic curve of 0.74. When CFR of <2.0 measured in the coronary sinus was considered as global myocardial ischemia, combined assessment provided correct reclassifications in 7 patients with false‐negative myocardial ischemia, and improved the diagnostic concordance to 92% sensitivity and 73% specificity with the area under receiver operating characteristic curve of 0.88 (95% confidence interval, 0.80%–0.97%, P=0.002). CONCLUSIONS: Visual analysis of stress‐rest perfusion CMR has limited concordance with FFR in patients with multivessel disease. Multiparametric CMR integrating stress‐rest perfusion CMR and flow measurement in the coronary sinus is useful for detecting reduced FFR in multivessel disease.