Coronary physiology in patients with severe aortic stenosis: Comparison between fractional flow reserve and instantaneous wave-free ratio
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Roberto Scarsini1, Gabriele Pesarini1, Carlo Zivelonghi1
1Division of Cardiology, Department of Medicine, University of Verona, Italy.
Insights
The conventional instantaneous wave-free ratio (iFR) threshold has lower diagnostic accuracy for coronary artery disease in severe aortic stenosis patients. A lower iFR cut-off is needed for accurate assessment in this population.
Area of Science:
- Cardiology
- Interventional Cardiology
- Diagnostic Imaging
Background:
- Functional assessment of coronary artery disease (CAD) in patients with severe aortic stenosis (AS) lacks validation.
- Optimal physiological investigation strategies for coronary stenosis in AS patients remain undetermined.
Purpose of the Study:
- To compare the diagnostic performance of instantaneous wave-free ratio (iFR) and fractional flow reserve (FFR) in patients with severe AS.
- To evaluate the agreement between iFR and FFR in assessing coronary lesions in AS patients.
Main Methods:
- Investigated 179 coronary lesions in 85 AS patients using on-line iFR and FFR.
- Compared diagnostic performance with a control group of 167 patients (290 lesions) with stable CAD without AS.
- Tested iFR-FFR agreement using the conventional 0.80 FFR cut-off.
Main Results:
- iFR and FFR correlation was similar between AS and CAD groups (AUC 0.97 vs 0.96).
- Conventional iFR cut-off (0.89) showed significantly lower diagnostic accuracy in AS patients (76.3%) compared to CAD patients (86.1%).
- An optimized iFR cut-off of 0.83 for AS patients significantly improved accuracy (91.3%) and maintained high negative predictive value (95.5%).
Conclusions:
- The conventional iFR cut-off has reduced diagnostic agreement with FFR in severe AS patients.
- Severe AS influences iFR ischemic thresholds, necessitating further comparative studies to establish optimal cut-offs.
Background:
The functional assessment of coronary artery disease (CAD) in patients with aortic stenosis (AS) has not been validated so far, and the best strategy to physiologically investigate the relevance of coronary stenosis in this specific setting of patients remains undetermined. The aim of the study is to compare the diagnostic performance of instantaneous wave-free ratio (iFR) and fractional flow reserve (FFR) in patients with severe AS.
Methods:
The functional significance of 179 coronary lesions was investigated with on-line iFR and FFR measurements in 85 AS patients and compared with a control group formed by 167 patients (290 lesions) with stable CAD and without AS. The iFR-FFR diagnostic agreement has been tested using the conventional 0.80 FFR cut-off.
Results:
The correlation between iFR and FFR was similar between AS and CAD patients, as well as the area under the curve at ROC curve analysis (0.97 vs 0.96, p=0.88). However, using the standard iFR 0.89 threshold, the diagnostic accuracy of iFR was significantly lower in AS compared with CAD (76.3% vs 86.1%, p=0.009). According to ROC analysis, the best iFR cut-off in predicting FFR≤0.8 was lower in AS (0.83, J=0.82) compared with CAD (0.89, J=0.81). Using the ROC derived cut-off of 0.83, the iFR accuracy increased significantly (91.3%, p=0.003) while maintaining an elevated negative predictive value (95.5%).
Conclusions:
In the presence of severe AS, conventional iFR cut-off had lower diagnostic agreement with FFR classification of coronary lesions compared to stable CAD patients. AS seems to influence iFR cut-off ischemic thresholds and deserves further comparative studies.
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