Resting Pressure Indices Equivalence — EECC MCQ

Correct answer: D — RFR, DFR, and dPR are alternative resting indices that measure pressure ratios at the lowest resistance point of the cardiac cycle; they are concordant with iFR in >95% of cases and can be used interchangeably — all have the same ≤0.89 significance threshold

Following the validation of iFR (DEFINE-FLAIR, iFR-SWEDEHEART), several alternative resting coronary pressure indices have been developed: RFR (resting full-cycle ratio), DFR (diastolic hyperaemia-free ratio), and dPR (diastolic pressure ratio). These indices use slightly different algorithms but all identify the lowest resistance period of the cardiac cycle for pressure measurement — without requiring adenosine. Cross-validation studies show >95% concordance with iFR, and the same ≤0.89 threshold applies. The 2024 ESC CCS Guidelines recognise all validated non-hyperaemic pressure ratios (NHPR) as equivalent alternatives to iFR and FFR for physiological lesion assessment (Class I, LOE A). The practical advantage: any compatible pressure wire system can provide physiological assessment without adenosine.

Reference: ESC (2024): CCS Guidelines