Correlation between intracoronary physiology and myocardial perfusion imaging in patients with severe aortic stenosis. (1st October 2019) - Scarsini, Roberto
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 < 0.89) was observed using iFR vs FFR: 39% vs 12%, p = 0.011. Using a pre-specified 0.82 cut-off, the iFR agreement with SPECT increased to 73%. 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. Highlights: FFR and iFR have not been validated in patients with severe aortic stenosis (AS). The role of physiology in guiding revascularization in AS remains controversial. FFR demonstrated substantial agreement with myocardial perfusion imaging. iFR agreement with myocardial perfusion imaging was inferior compared with FFR. iFR diagnostic performance increased using a prespecified lower cut-off (0.82).