Related Experiment Video
Updated: Nov 30, 2025
Ultrasound Based Assessment of Coronary Artery Flow and Coronary Flow Reserve Using the Pressure Overload Model in Mice
Published on: April 13, 2015
Borderline coronary lesion assessment with quantitative flow ratio and its relation to the instantaneous wave-free
Paweł Kleczyński1, Artur Dziewierz2, Łukasz Rzeszutko2
1Jagiellonian University Medical College, Faculty of Medicine, Institute of Cardiology, Department of Interventional Cardiology, John Paul II Hospital, Krakow, Poland.
Insights
Quantitative flow ratio (QFR) shows good correlation with instantaneous wave-free ratio (iFR) for assessing borderline coronary artery disease. Further iFR assessment may be needed in some cases after QFR evaluation.
Area of Science:
- Cardiovascular medicine
- Interventional cardiology
- Diagnostic imaging
Background:
- Borderline coronary artery disease requires accurate functional assessment.
- Quantitative flow ratio (QFR) is an emerging image-based index.
- Instantaneous wave-free ratio (iFR) is a pressure wire-derived index used for functional assessment.
Purpose of the Study:
- To investigate the correlation between QFR and iFR.
- To evaluate QFR's diagnostic performance in assessing intermediate coronary stenoses.
Main Methods:
- 110 vessels with borderline coronary lesions (40-90% stenosis) were analyzed.
- QFR was derived from angiography without hyperemia.
- Pressure wire-derived iFR served as the reference standard.
Main Results:
- QFR showed good agreement with iFR (ICC=0.87).
- QFR demonstrated high diagnostic accuracy (AUC=0.87) for detecting significant ischemia (iFR ≤0.89).
- Optimal QFR cutoff of 0.79 yielded 76.3% sensitivity and 83.3% specificity.
Conclusions:
- QFR is a reliable tool for assessing functional ischemia in intermediate coronary lesions.
- QFR demonstrates good diagnostic performance and correlation with iFR.
- Pressure wire-based iFR may still be necessary in approximately two-thirds of patients post-QFR.
Purpose:
Quantitative flow ratio (QFR) is a recently developed image-based index for the assessment of borderline coronary artery disease. We sought to investigate a correlation between QFR and instantaneous wave-free ratio (iFR) for the assessment of intermediate coronary stenoses.
Materials And Methods:
Patients with borderline coronary lesions (40-90% by visual assessment) undergoing iFR assessment were enrolled. QFR was derived from a modeled hyperemic flow velocity derived from angiography without adenosine-induced hyperemia. Pressure wire-derived iFR served as the reference.
Results:
Values of QFR and iFR from 110 vessels with a mean percent diameter stenosis of 44.6 ± 12.0% were compared. Mean iFR was 0.90 ± 0.07 and 38 (34.5%) had iFR ≤0.89. Mean QFR was 0.81 ± 0.10 and 44 (40%) had QFR ≤0.80. A good agreement between QFR and iFR measurements was confirmed with a mean difference of 0.09 (95%CI -0.027 to 0.207) and intraclass correlation coefficient of 0.87 (95%CI 0.81-0.91). The overall diagnostic accuracy (AUC in ROC analysis) of QFR in detecting iFR ≤0.89 was 0.87 (95%CI 0.79-0.93; p < 0.001). Regarding iFR ≤0.89, the optimal cutoff value of QFR was 0.79 with sensitivity, specificity, and accuracy of 76.3%, 83.3%, and 80.0%, respectively. A 100% sensitivity was observed for a QFR cutoff value of 0.88 and a 100% specificity for a QFR cutoff value of 0.69.
Conclusions:
Our study confirmed good QFR diagnostic performance and correlation with iFR for detecting the functional ischemia caused by intermediate lesions in coronary arteries. However, the pressure wire assessment with iFR might be warranted in 2/3 of patients after QFR assessment.
