Accuracy of Intravascular Ultrasound-Based Fractional Flow Reserve in Identifying Hemodynamic Significance of Coronary Stenosis

Abstract

Background: Ultrasonic flow ratio (UFR) is a novel method for fast computation of fractional flow reserve (FFR) from intravascular ultrasound images. The objective of this study is to evaluate the diagnostic performance of UFR using wire-based FFR as the reference. Methods: Post hoc computation of UFR was performed in consecutive patients with both intravascular ultrasound and FFR measurement in a core lab while the analysts were blinded to FFR. Results: A total of 167 paired comparisons between UFR and FFR from 94 patients were obtained. Median FFR was 0.80 (interquartile range, 0.68–0.89) and 50.3% had a FFR≤0.80. Median UFR was 0.81 (interquartile range, 0.69–0.91), and UFR showed strong correlation with FFR ( r =0.87; P <0.001). The area under the curve was higher for UFR than intravascular ultrasound-derived minimal lumen area (0.97 versus 0.89, P <0.001). The diagnostic accuracy, sensitivity, specificity, positive predictive value, negative predictive value, positive likelihood ratio, and negative likelihood ratio for UFR to identify FFR≤0.80 was 92% (95% CI, 87–96), 91% (95% CI, 82–96), 96% (95% CI, 90–99), 96% (95% CI, 89–99), 91% (95% CI, 93–96), 25.0 (95% CI, 8.2–76.2), and 0.10 (95% CI, 0.05–0.20), respectively. The agreement between UFR and FFR was independent of lesion locations ( P =0.48), prior myocardial infarction ( P =0.29), and imaging catheters ( P =0.22). Intraobserver and interobserver variability of UFR analysis was 0.00±0.03 and 0.01±0.03, respectively. Median UFR analysis time was 102 (interquartile range, 87–122) seconds. Conclusions: UFR had a strong correlation and good agreement with FFR. The fast computational time and excellent analysis reproducibility of UFR bears the potential of a wider adoption of integration of coronary imaging and physiology in the catheterization laboratory.

Fibre optic intravascular measurements of blood flow: A review

“…For performing intravascular microstructural imaging, IV-OCT is complementary to intravascular ultrasound (IVUS). A similar complementarity may emerge between quantitative flow measurements performed with IV-DOCT and those with IVUS [140,141]. The slower pullback speeds of IVUS, as compared with those of OCT, are a disadvantage in terms of limiting the effects of cardiac motion for computational flow measurements [141]; however, IVUS does not require flushing, which can be advantageous in terms of covering greater distances with a pullback.…”

“…A similar complementarity may emerge between quantitative flow measurements performed with IV-DOCT and those with IVUS [140,141]. The slower pullback speeds of IVUS, as compared with those of OCT, are a disadvantage in terms of limiting the effects of cardiac motion for computational flow measurements [141]; however, IVUS does not require flushing, which can be advantageous in terms of covering greater distances with a pullback. The spatial resolution of OCT is higher than that of IVUS, which may be advantageous for resolving fine variations in flow within a vessel.…”

“…The spatial resolution of OCT is higher than that of IVUS, which may be advantageous for resolving fine variations in flow within a vessel. Lumen delineation with IVUS and OCT has recently been used to obtain computational FFR estimates [141][142][143][144].…”

Diagnostic performance of deep learning and computational fluid dynamics-based instantaneous wave-free ratio derived from computed tomography angiography

“…Time efficiency is a key factor in diagnosing patients with CAD, and shortening diagnosis time is of great clinically significance. The optimal cut-off values for OCT-FFR and IVUS-FFR were 0.80 [ 30 , 31 ]. As a result, we used AccuiFRct ≤ 0.89 as the optimal threshold for predicting ischemic lesions.…”

Coronary physiologic assessment based on angiography and intracoronary imaging

“…Recently, a novel method was developed for fast computation of IVUS-based FFR called ultrasonic flow ratio (UFR) using a prototype software package (IvusPlus prototype, Pulse Medical Imaging Technology) [36] . The software is AI-based, which allows autodelineation of lumen contours and the external elastic lamina to generate 3D reconstruction of the interrogated vessel ( Fig.…”