Impaired Myocardial Perfusion on Stress CMR Correlates With Invasive FFR in Children With Coronary Anomalies.

BACKGROUND Invasive fractional flow reserve (FFR) is considered the gold standard to evaluate coronary artery flow. Stress cardiovascular magnetic resonance (sCMR) is an emerging non-invasive tool to evaluate myocardial perfusion in children. We sought to compare sCMR with FFR to determine impaired intracoronary flow in children with anomalous aortic origin of a coronary artery (AAOCA) and/or myocardial bridge (MB) who presented concern for myocardial ischemia. METHODS From December 2012 to May 2019, AAOCA and/or MB patients (<20 years old) were prospectively enrolled and underwent sCMR and FFR. Abnormal sCMR included perfusion/regional wall-motion abnormality in the involved coronary distribution. FFR was performed at baseline and with dobutamine/regadenoson and considered abnormal if <0.8 in the affected coronary segment. RESULTS Of 376 patients evaluated, a total of 19 (age range, 0.2-17 years) underwent 24 sets of sCMR and FFR studies, with 5 repeat studies following intervention. Types of anomalies included 6 isolated MB/normal CA origins, 5 single CAs, 5 left AAOCAs, and 3 right AAOCAs. Seventeen patients (89.5%) had MB/intramyocardial course - 14 involving the left anterior descending coronary artery and 3 with multivessel involvement. sCMR correlated with FFR in 19/24 sets (7 sCMR and FFR positive, 12 sCMR and FFR negative) and it did not correlate in 5/24 sets. The positive percent agreement was 77.8%, negative percent agreement was 80.0%, and overall percent agreement was 79.2%. CONCLUSIONS Assessment of myocardial perfusion using non-invasive sCMR concurred with FFR, particularly if performed with close proximity in time, and may contribute to risk stratification and decision making in children with AAOCA and/or MB.