Abstract
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 (FFR(Dobutamine)) 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 mm(2) in systole; from 7.6 to 3.7 mm(2) in diastole), while FFR(Dobutamine) was 0.85 and iFR(Dobutamine) was 0.72. DISCUSSION: The patient's iFR(Dobutamine) matched geometrical changes and clinical presentation, while his FFR(Dobutamine) underestimated ischemia. TAKE-HOME MESSAGE: In the case of predominant diastolic, stress-induced intramural deformation of the R-AAOCA vessel, iFR(Dobutamine)-targeting diastolic stress-pressure ratio-may be preferred over FFR(Dobutamine), as the latter may miss ischemia given its cardiac cycle-averaged hyperemic calculations.