Diagnostic Performance of In‐Procedure Angiography‐Derived Quantitative Flow Reserve Compared to Pressure‐Derived Fractional Flow Reserve: The FAVOR II Europe‐Japan Study

Abstract

BackgroundQuantitative flow ratio (QFR) is a novel modality for physiological lesion assessment based on 3‐dimensional vessel reconstructions and contrast flow velocity estimates. We evaluated the value of online QFR during routine invasive coronary angiography for procedural feasibility, diagnostic performance, and agreement with pressure‐wire–derived fractional flow reserve (FFR) as a gold standard in an international multicenter study.Methods and Results FAVOR II E‐J (Functional Assessment by Various Flow Reconstructions II Europe‐Japan) was a prospective, observational, investigator‐initiated study. Patients with stable angina pectoris were enrolled in 11 international centers. FFR and online QFR computation were performed in all eligible lesions. An independent core lab performed 2‐dimensional quantitative coronary angiography (2D‐QCA) analysis of all lesions assessed with QFR and FFR. The primary comparison was sensitivity and specificity of QFR compared with 2D‐QCA using FFR as a reference standard. A total of 329 patients were enrolled. Paired assessment of FFR, QFR, and 2D‐QCA was available for 317 lesions. Mean FFR, QFR, and percent diameter stenosis were 0.83±0.09, 0.82±10, and 45±10%, respectively. FFR was ≤0.80 in 104 (33%) lesions. Sensitivity and specificity by QFR was significantly higher than by 2D‐QCA (sensitivity, 86.5% (78.4–92.4) versus 44.2% (34.5–54.3); P<0.001; specificity, 86.9% (81.6–91.1) versus 76.5% (70.3–82.0); P=0.002). Area under the receiver curve was significantly higher for QFR compared with 2D‐QCA (area under the receiver curve, 0.92 [0.89–0.96] versus 0.64 [0.57–0.70]; P<0.001). Median time to QFR was significantly lower than median time to FFR (time to QFR, 5.0 minutes [interquartile range, –6.1] versus time to FFR, 7.0 minutes [interquartile range, 5.0–10.0]; P<0.001).ConclusionsOnline computation of QFR in the catheterization laboratory is clinically feasible and is superior to angiographic assessment for evaluation of intermediary coronary artery stenosis using FFR as a reference standard.Clinical Trial Registration URL: https://www.clinicaltrials.gov. Unique identifier: NCT02959814.

Quantitative flow ratio for immediate assessment of nonculprit lesions in patients with ST‐segment elevation myocardial infarction—An iSTEMI substudy

“…The diagnostic performance of QFR with FFR as reference is well documented in patients with stable angina . Our data indicate that QFR might also be a valuable tool in the evaluation of NCLs in patients with acute STEMI undergoing primary PCI.…”

“…The complete list of anatomical and angiographic exclusion criteria is presented in Supporting Information Table S1. These criteria for QFR analysis match those of prior QFR studies …”

Diagnostic performance of quantitative flow ratio in prospectively enrolled patients: An individual patient‐data meta‐analysis

“…For patients undergoing invasive coronary angiography, QFR may be the obvious preferred functional imaging alternative, as it is easier to integrate in the workflow of the catheterization laboratory workflow than CT‐FFR. Further, QFR is computed within the time of conventional FFR measurements . Hence, it is promising that diagnostic performance of QFR in comparison to FFR appears to be at least as good as was shown for iFR in the early validation studies of that technology .…”

“…For 2D‐ and 3D‐QCA, ≥50% DS was used as diagnostic cut‐off. The acquisition guide for QFR computation was previously published for FAVOR II E‐J . QFR analysis in the remaining studies followed the same principles.…”

“…To improve access to functional lesion evaluation during invasive coronary angiography, quantitative flow ratio (QFR) based on three‐dimensional reconstruction of coronary arteries and application of mathematical equations was recently developed. Validation of QFR in mid‐sized prospective studies showed good diagnostic accuracy of QFR in core‐lab and in‐procedure settings using FFR as the reference standard with an overall classification agreement ranging between 80 and 90% . In this systematic, individual participant data meta‐analysis based on prospective studies, we aimed to evaluate the diagnostic performance of the CE‐marked QFR algorithm (Medis medical imaging b.v. and Pulse Medical Imaging Technology Co.) and identify predictors for discrepancy between QFR and FFR.…”