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

<jats:sec xml:lang="en"> <jats:title>Background</jats:title> <jats:p xml:lang="en"> Quantitative flow ratio ( <jats:styled-content style="fixed-case">QFR</jats:styled-content> ) 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 <jats:styled-content style="fixed-case">QFR</jats:styled-content> during routine invasive coronary angiography for procedural feasibility, diagnostic performance, and agreement with pressure‐wire–derived fractional flow reserve ( <jats:styled-content style="fixed-case">FFR</jats:styled-content> ) as a gold standard in an international multicenter study. </jats:p> </jats:sec> <jats:sec xml:lang="en"> <jats:title>Methods and Results</jats:title> <jats:p xml:lang="en"> <jats:styled-content style="fixed-case">FAVOR II</jats:styled-content> 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. <jats:styled-content style="fixed-case">FFR</jats:styled-content> and online <jats:styled-content style="fixed-case">QFR</jats:styled-content> computation were performed in all eligible lesions. An independent core lab performed 2‐dimensional quantitative coronary angiography (2D‐ <jats:styled-content style="fixed-case">QCA</jats:styled-content> ) analysis of all lesions assessed with <jats:styled-content style="fixed-case">QFR</jats:styled-content> and <jats:styled-content style="fixed-case">FFR</jats:styled-content> . The primary comparison was sensitivity and specificity of <jats:styled-content style="fixed-case">QFR</jats:styled-content> compared with 2D‐ <jats:styled-content style="fixed-case">QCA</jats:styled-content> using <jats:styled-content style="fixed-case">FFR</jats:styled-content> as a reference standard. A total of 329 patients were enrolled. Paired assessment of <jats:styled-content style="fixed-case">FFR</jats:styled-content> , <jats:styled-content style="fixed-case">QFR,</jats:styled-content> and 2D‐ <jats:styled-content style="fixed-case">QCA</jats:styled-content> was available for 317 lesions. Mean <jats:styled-content style="fixed-case">FFR</jats:styled-content> , <jats:styled-content style="fixed-case">QFR,</jats:styled-content> and percent diameter stenosis were 0.83±0.09, 0.82±10, and 45±10%, respectively. <jats:styled-content style="fixed-case">FFR</jats:styled-content> was ≤0.80 in 104 (33%) lesions. Sensitivity and specificity by <jats:styled-content style="fixed-case">QFR</jats:styled-content> was significantly higher than by 2D‐ <jats:styled-content style="fixed-case">QCA</jats:styled-content> (sensitivity, 86.5% (78.4–92.4) versus 44.2% (34.5–54.3); <jats:italic>P</jats:italic> <0.001; specificity, 86.9% (81.6–91.1) versus 76.5% (70.3–82.0); <jats:italic>P</jats:italic> =0.002). Area under the receiver curve was significantly higher for <jats:styled-content style="fixed-case">QFR</jats:styled-content> compared with 2D‐ <jats:styled-content style="fixed-case">QCA</jats:styled-content> ( <jats:styled-content style="fixed-case">area under the receiver curve,</jats:styled-content> 0.92 [0.89–0.96] versus 0.64 [0.57–0.70]; <jats:italic>P</jats:italic> <0.001). Median time to <jats:styled-content style="fixed-case">QFR</jats:styled-content> was significantly lower than median time to <jats:styled-content style="fixed-case">FFR</jats:styled-content> (time to <jats:styled-content style="fixed-case">QFR,</jats:styled-content> 5.0 minutes [ <jats:styled-content style="fixed-case">interquartile range</jats:styled-content> , –6.1] versus time to <jats:styled-content style="fixed-case">FFR,</jats:styled-content> 7.0 minutes [ <jats:styled-content style="fixed-case">interquartile range,</jats:styled-content> 5.0–10.0]; <jats:italic>P</jats:italic> <0.001). </jats:p> </jats:sec> <jats:sec xml:lang="en"> <jats:title>Conclusions</jats:title> <jats:p xml:lang="en"> Online computation of <jats:styled-content style="fixed-case">QFR</jats:styled-content> in the catheterization laboratory is clinically feasible and is superior to angiographic assessment for evaluation of intermediary coronary artery stenosis using <jats:styled-content style="fixed-case">FFR</jats:styled-content> as a reference standard. </jats:p> </jats:sec> <jats:sec xml:lang="en"> <jats:title>Clinical Trial Registration</jats:title> <jats:p xml:lang="en"> <jats:styled-content style="fixed-case">URL</jats:styled-content> : <jats:ext-link xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="uri" xlink:href="https://www.clinicaltrials.gov">https://www.clinicaltrials.gov</jats:ext-link> . Unique identifier: <jats:styled-content style="fixed-case">NCT</jats:styled-content> 02959814. </jats:p> </jats:sec>