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Updated: Jan 4, 2026
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Employing the Forced Oscillation Technique for the Assessment of Respiratory Mechanics in Adults
Published on: February 9, 2022
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Vive la difference: Factors and mechanisms predicting discrepancy between iFR and FFR
Morton J Kern1, Arnold H Seto1
1Veterans Administration Long Beach Health Care System, University of California, Irvine, California.
Summary
Fractional Flow Reserve (FFR) and instantaneous wave-Free Ratio (iFR) discordance occurs in 15-20% of cases. Lesion location, severity, and bradycardia predict this discordance, guiding revascularization decisions.
Area of Science:
- Cardiovascular physiology
- Interventional cardiology
- Diagnostic imaging
Background:
- Fractional Flow Reserve (FFR) and instantaneous wave-Free Ratio (iFR) are crucial for guiding revascularization in coronary artery disease.
- Discordance between FFR and iFR occurs in 15-20% of cases, leading to clinical uncertainty.
- The CONTRAST substudy investigated predictors of this discordance.
Discussion:
- Lesion location, severity, and bradycardia were identified as significant predictors of FFR/iFR discordance.
- Age was found to be a less significant predictor.
- Physiological mechanisms underlying resting and hyperemic pressure loss explain these predictors in atherosclerotic stenoses.
Key Insights:
- Understanding predictors of FFR/iFR discordance is essential for accurate revascularization decisions.
- Lesion characteristics and patient factors like bradycardia influence the agreement between FFR and iFR.
- A physiological approach can reconcile discrepancies between the two methods.
Outlook:
- Further validation of the proposed logical approach integrating both resting and hyperemic pressure ratios is warranted.
- Improved diagnostic strategies may reduce unnecessary interventions and optimize patient outcomes.
- Continued research into the interplay of lesion physiology and hemodynamic indices will refine clinical practice.
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