Abstract 368: Contrast-Functional Flow Reserve vs. Instantaneous Wave-Free Ratio for Functional Assessment of Coronary Stenosis: A Systematic Review and Meta-analysis

Abstract

Background: Fractional flow reserve (FFR) remains underutilized due to practical concerns related to the need for hyperemic agents. Adenosine-free indexes including instantaneous wave-free ratio (iFR) and contrast-FFR (cFFR) are newly proposed modalities to circumvent the use of vasodilators. We performed this meta-analysis to assess the diagnostic performance of cFFR and iFR in evaluating coronary stenosis severity with FFR as the reference standard. Methods: A comprehensive literature search of PUBMED, EMBASE, and Cochrane databases was conducted in September 2019 to include relevant studies with the diagnostic accuracy of iFR or cFFR referenced to FFR. Correlation data were extracted from individual studies and then pooled using a random effect model as Pearson's correlation, with 95% confidence intervals. We used Cochran's Q test and I 2 index to assess heterogeneity. Results: A total of 16 studies involving 6370 patients were included in the analysis. Overall, 4822 and 2021 coronary lesions were evaluated by iFR and cFFR, respectively. The Pearson's correlations were 0.80 (95%CI 0.78-0.81, I 2 63%) and 0.92 (95%CI 0.90-0.94, I 2 81%) for iFR and cFFR, respectively. The pooled sensitivity and specificity were 83% (95%CI 0.77-0.88) and specificity of 82% (95%CI 0.78-0.85) for iFR and 88% (95%CI 0.75-0.95) and 93% (95%CI 0.87-0.96) for cFFR, respectively. Conclusions: Our meta-analysis demonstrates that cFFR has higher correlation than iFR in functional assessment of coronary stenosis when FFR is used as the standard reference. Further studies are warranted to evaluate the accuracy of cFFR in detecting functional ischemia.