Abstract 15380: Diagnostic Performance of Ultrasonic Flow Ratio versus Quantitative Flow Ratio for Assessment of Coronary Artery Stenosis

Abstract

Introduction: Ultrasonic flow ratio (UFR) is a novel intravascular ultrasound (IVUS)-derived method for fast computation of fractional flow reserve (FFR) without pressure wires and adenosine. Aims: The aim of this study was to evaluate the diagnostic performance of UFR and compare it with angiography-based quantitative flow ratio (QFR), using FFR as the reference standard. Methods: Patients who underwent coronary angiography, IVUS and FFR were analyzed. UFR and QFR was computed offline in a central core-lab by independent analysts blinded to FFR. Results: A total of 111 paired comparisons between UFR, QFR and FFR from 56 patients were analyzed. UFR showed a numerically better correlation (r=0.83 vs. 0.79; p=0.27) and significant better agreement (standard deviation of the difference=0.07 vs. 0.08; p=0.02) with FFR than QFR. Diagnostic accuracy, sensitivity, specificity, positive predictive value, negative predictive value, positive likelihood ratio and negative likelihood ratio for UFR to predict FFR was 92% (95% CI: 85%-96%), 85% (95% CI: 71%-94%), 97% (95% CI: 89%-99%), 95% (95% CI: 83%-99%), 90% (95% CI: 82%-95%), 27.6 (95% CI: 7.0-108.4), and 0.16 (95% CI: 0.08-0.31), respectively. The area under curve for UFR to predict an FFR ≤ 0.80 was 0.94, is equivalent to QFR (difference=0.04; p=0.23), and higher than minimal lumen area (difference=0.09, p=0.006). Diagnostic accuracy was not significantly different in bifurcation lesions, nor in non-bifurcation lesions. Conclusions: The UFR showed good diagnostic concordance with FFR, equivalent to QFR. The good diagnostic performance of UFR provides a potentiality for the integration of physiological assessment and intravascular imaging in real-world clinical practice.