Correlation between intracoronary physiology and myocardial perfusion imaging in patients with severe aortic stenosis

Abstract Background Aortic stenosis (AS) is frequently associated with coronary artery disease (CAD). However, the best tool to functionally assess CAD in AS remains undetermined. Fractional flow reserve (FFR) and instantaneous wave-free ratio (iFR) have never been validated in AS. Methods FFR, iFR and stress single photon emission computed tomography (SPECT) were performed in a consecutive series of 28 patients with severe AS and 41 borderline coronary lesions during the work-up for valve replacement. Results Both FFR and iFR were correlated with an abnormal SPECT. At ROC analysis, FFR yielded an AUC = 0.91 with negative predictive value (NPV) = 95% in detecting ischemia according to SPECT. iFR showed significant worse agreement with myocardial perfusion imaging compared to FFR (59% vs 85%, p = 0.014). Specifically, a significant larger proportion of false positive measurements (negative SPECT and iFR  Conclusions FFR yielded a good correlation with SPECT and a high NPV in detecting ischemia-provoking lesions. iFR diagnostic metrics were inferior compared with FFR and improved adopting a lower ischemic threshold.