An 11-Year-old Athlete with Dynamic Stenosis of Coronary Artery Anomaly with Normal FFR-Dobutamine but Abnormal Ifr-Dobutamine

BACKGROUND:Anomalous aortic origin of a right coronary artery (R-AAOCA) can cause stress-induced ischemia owing to dynamic stenosis of the intramural course. While fractional flow reserve during dobutamine challenge (FFRDobutamine) is the reference standard for hemodynamic assessment, specific scenarios favoring instantaneous wave-free ratio (iFR) over FFR remain unclear. CASE SUMMARY:An 11-year-old male competitive basketball athlete with exertional angina and R-AAOCA underwent invasive angiography. Intravascular ultrasound showed a reduction in the intramural coronary lumen cross-sectional areafrom rest to dobutamine stress (from 4.6 to 3.1 mm2 in systole; from 7.6 to 3.7 mm2 in diastole), while FFRDobutamine was 0.85 and iFRDobutamine was 0.72. DISCUSSION:The patient's iFRDobutamine matched geometrical changes and clinical presentation, while his FFRDobutamine underestimated ischemia. TAKE-HOME MESSAGE:In the case of predominant diastolic, stress-induced intramural deformation of the R-AAOCA vessel, iFRDobutamine-targeting diastolic stress-pressure ratio-may be preferred over FFRDobutamine, as the latter may miss ischemia given its cardiac cycle-averaged hyperemic calculations.