An 11-Year-Old Athlete With Dynamic Stenosis of Coronary Artery Anomaly With Normal FFR-Dobutamine But Abnormal...

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.

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 FFR_Dobutamine was 0.85 and iFR_Dobutamine was 0.72.

The patient's iFR_Dobutamine matched geometrical changes and clinical presentation, while his FFR_Dobutamine underestimated ischemia.

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.