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Updated: Oct 6, 2025
Ultrasound Based Assessment of Coronary Artery Flow and Coronary Flow Reserve Using the Pressure Overload Model in Mice
Published on: April 13, 2015
Characterization of quantitative flow ratio and fractional flow reserve discordance using doppler flow and clinical
Jelmer Westra1, Ashkan Eftekhari1, Mick Renkens2
1Department of Cardiology, Aarhus University Hospital, Palle Juul Jensens Boulevard 99, 8200, Aarhus N, Denmark.
Insights
Physiological mechanisms causing disagreement between fractional flow reserve (FFR) and quantitative flow ratio (QFR) are unclear. This study found that differences in coronary flow reserve, microvascular resistance, and lesion severity partly explain FFR-QFR discordance.
Area of Science:
- Cardiovascular Physiology
- Interventional Cardiology
- Medical Imaging Analysis
Background:
- Fractional flow reserve (FFR) and quantitative flow ratio (QFR) are used to assess coronary artery stenosis severity.
- Disagreement between FFR and QFR can impact clinical decision-making.
- The underlying physiological mechanisms of FFR-QFR discordance are not fully understood.
Purpose of the Study:
- To characterize the coronary flow and resistance profile in intermediate stenosed epicardial coronary arteries.
- To compare physiological and anatomical parameters in lesions with concordant and discordant FFR and QFR values.
- To assess the association of QFR with two-year target vessel failure in non-revascularized vessels.
Main Methods:
- Post-hoc analysis of the DEFINE-FLOW study data.
- Comparison of anatomical and Doppler-derived physiological parameters for different FFR/QFR concordance groups.
- Assessment of the association between QFR and target vessel failure using Cox proportional hazards models.
Main Results:
- Lesions with discordant FFR/QFR (FFR+QFR-) showed higher coronary flow reserve, lower hyperemic microvascular resistance, and less anatomical severity compared to FFR+QFR+ lesions.
- Lesions with FFR-QFR+ discordance had more severe anatomical stenosis but similar coronary flow reserve and hyperemic microvascular resistance compared to FFR-QFR- lesions.
- FFR demonstrated higher agreement and diagnostic performance than QFR and coronary flow reserve when using hyperemic stenosis resistance as the reference standard.
Conclusions:
- Disagreement between FFR and QFR is partly explained by variations in physiological factors (coronary flow reserve, microvascular resistance) and anatomical lesion severity.
- FFR, validated against hyperemic stenosis resistance, shows robust performance in assessing coronary stenosis.
- Further research is needed to fully elucidate the complex interplay of factors contributing to FFR-QFR discordance.
Abstract:
The physiological mechanisms of quantitative flow ratio and fractional flow reserve disagreement are not fully understood. We aimed to characterize the coronary flow and resistance profile of intermediate stenosed epicardial coronary arteries with concordant and discordant FFR and QFR. Post-hoc analysis of the DEFINE-FLOW study. Anatomical and Doppler-derived physiological parameters were compared for lesions with FFR+QFR- (n = 18) vs. FFR+QFR+ (n = 43) and for FFR-QFR+ (n = 34) vs. FFR-QFR- (n = 139). The association of QFR results with the two-year rate of target vessel failure was assessed in the proportion of vessels (n = 195) that did not undergo revascularization. Coronary flow reserve was higher [2.3 (IQR: 2.1-2.7) vs. 1.9 (IQR: 1.5-2.4)], hyperemic microvascular resistance lower [1.72 (IQR: 1.48-2.31) vs. 2.26 (IQR: 1.79-2.87)] and anatomical lesion severity less severe [% diameter stenosis 45.5 (IQR: 41.5-52.5) vs. 58.5 (IQR: 53.1-64.0)] for FFR+QFR- lesions compared with FFR+QFR+ lesions. In comparison of FFR-QFR+ vs. FFR-QFR- lesions, lesion severity was more severe [% diameter stenosis 55.2 (IQR: 51.7-61.3) vs. 43.4 (IQR: 35.0-50.6)] while coronary flow reserve [2.2 (IQR: 1.9-2.9) vs. 2.2 (IQR: 1.9-2.6)] and hyperemic microvascular resistance [2.34 (IQR: 1.85-2.81) vs. 2.57 (IQR: 2.01-3.22)] did not differ. The agreement and diagnostic performance of FFR using hyperemic stenosis resistance (> 0.80) as reference standard was higher compared with QFR and coronary flow reserve. Disagreement between FFR and QFR is partly explained by physiological and anatomical factors. Clinical Trials Registration https://www.clinicaltrials.gov ; Unique identifier: NCT01813435.
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