Abstract 12127: Diagnostic Performance of Fractional Flow Reserve, Instantaneous Wave-Free Ratio and Quantitative Flow Ratio, on the Same Patient and Procedure

Abstract

Introduction: Contemporary percutaneous coronary intervention (PCI) seeks precision and physiological assessment of coronary artery stenosis. Fractional Flow Reserve (FFR) is currently the gold standard for lesion physiology assessment; however, it's invasive and expensive. Other modalities, such as Quantitative Flow Ratio (QFR) and Instantaneous Wave-Free Ratio (iFR), can also determine the functional repercussion of coronary stenosis less invasively. Hypothesis: The results of FFR, iFR, and QFR of the same lesion, obtained during the same PCI, demonstrate the significant diagnostic capability of iFR and QFR, compared with FFR. Methods: Retrospective and unicentric study with stable chronic heart disease patients who underwent PCI. For every angiographic lesion, FFR, iFR and QFR were realized during the PCI. QFR was performed by an X-ray technician, blinded to the FFR and iFR results. A descriptive analysis was performed, as well as a correlation between the three measurements with Pearson’s r, chi-square, and ROC curve; and Bland-Altman plot for the results of FFR and QFR. Results: Thirty-six lesions of 27 patients were analyzed. For FFR, stenosis was considered significant when the result was <0.80, obtaining 17 lesions (52%) as significant; for iFR, it was <0.89, obtaining 14 significant lesions (38%); and for QFR, it was <0.85, resulting in 19 (52%) significant lesions. Considering that FFR is the actual gold standard, a ROC curve was used to analyze QFR, were the best cutoff value was 0.88 with a sensitivity of 88% and specificity of 64% (AUC of 0.86, 95% CI 0.736- 0.991, p<0.001), while for iFR the best cutoff value was 0.90 with a sensitivity of 82% and specificity of 74% (AUC of 0.85, 95% CI 0.722-0.984, p<0.001). Pearson’s r revealed a significant correlation between FFR-iFR (r=0.6, p<0.001), FFR-QFR (r=0.58, p<0.001), and QFR-iFR (r=0.62, p<0.001). Bland-Altman plot showed no significant difference between the data obtained with FFR and QFR. Chi-square test determined (p<0.001) that the three angiographic methods had a good correlation in determining whether a lesion was significant. Conclusion: The study demonstrated the significant diagnostic capability that the QFR and iFR methods have, when compared against the current gold standard FFR.