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.

In patients with intermediate-range coronary stenosis, FFR is effective in differentiating patients who do not require further diagnostic testing or intervention (FFR >0.80) from higher-risk patients (FFR ≤0.80) in whom further testing with invasive coronary angiography and possibly intervention may be needed. Further studies assessing the risk and optimal management strategy in patients undergoing first-line CTA with selective FFR testing are needed.

Objectives We aimed to provide robust performance estimates for quantitative flow ratio (QFR) in assessment of intermediary coronary lesions. Background Angiography‐based functional lesion assessment by QFR may appear as a cost saving and safe approach to expand the use of physiology‐guided percutaneous coronary interventions. QFR was proven feasible and showed good diagnostic performance in mid‐sized off‐line and on‐line studies with fractional flow reserve (FFR) as reference standard. Methods We performed a collaborative individual patient‐data meta‐analysis of all available prospective studies with paired assessment of QFR and FFR using the CE‐marked QFR application. The main outcome was agreement of QFR and FFR using a two‐step analysis strategy with a multilevel mixed model accounting for study and center level variation. Results Of 16 studies identified, four studies had prospective enrollment and provided patient level data reaching a total of 819 patients and 969 vessels with paired FFR and QFR: FAVOR Pilot (n = 73); WIFI II (n = 170); FAVOR II China (n = 304) and FAVOR II Europe‐Japan (n = 272). We found an overall agreement (mean difference 0.009 ± 0.068, I2 = 39.6) of QFR with FFR. The diagnostic performance was sensitivity 84% (95%CI: 77–90, I2 = 70.1), specificity 88% (95%CI: 84–91, I2 = 60.1); positive predictive value 80% (95%CI: 76–85, I2 = 33.4), and negative predictive value 95% (95%CI: 93–96, I2 = 75.9). Conclusions Diagnostic performance of QFR was good with FFR as reference in this meta‐analysis of high quality studies. QFR could provide an easy, safe, and cost‐effective solution for functional evaluation of coronary artery stenosis.

Background: In patients with increased bleeding risk, the biolimus A9-coated BioFreedom stent, a stainless steel drug-coated stent free from polymer, has shown superiority compared with a bare-metal stent. The aim of this study was to investigate whether the BioFreedom stent is noninferior to a modern ultrathin strut biodegradable polymer cobalt-chromium sirolimus-eluting Orsiro stent in an all-comers patient population treated with percutaneous coronary intervention. Methods: The SORT OUT IX trial (Scandinavian Organization for Randomized Trials With Clinical Outcome IX), was a large-scale, registry-based, randomized, multicenter, single-blind, 2-arm, noninferiority trial. The primary end point, major adverse cardiovascular events, was defined as the composite of cardiac death, myocardial infarction not related to any segment other than the target lesion, or target lesion revascularization within 1 year, analyzed by intention-to-treat. The trial was powered to assess noninferiority for major adverse cardiovascular events of the BioFreedom stent compared with the Orsiro stent with a predetermined noninferiority margin of 0.021. Results: Between December 14, 2015 and April 21, 2017, 3151 patients were assigned to treatment with the BioFreedom stent (1572 patients, 1966 lesions) or to the Orsiro stent (1579 patients, 1985 lesions). Five patients were lost to follow-up because of emigration (99.9% follow-up rate). Mean age was 66.3±10.9, diabetes mellitus was seen in 19.3% of patients, and 53% of the patients had acute coronary syndromes. At 1 year, intention-to-treat analysis showed that 79 (5.0%) patients, who were assigned the BioFreedom stent, and 59 (3.7%), who were assigned the Orsiro stent, met the primary end point (absolute risk difference 1.29% [upper limit of one-sided 95% CI 2.50%]; P noni nferiority =0.14). Significantly more patients in the BioFreedom stent group had target lesion revascularization than those in the Orsiro stent group (55 [3.5%] vs 20 [1.3%], rate ratio 2.77 [95% CI, 1.66–4.62]; P <0.0001). Conclusions: The biolimus A9-coated BioFreedom polymer-free stent did not meet criteria for noninferiority for major adverse cardiovascular events at 12 months when compared with the ultrathin strut biodegradable polymer sirolimus-eluting Orsiro stent in an all-comers population Registration: URL: https://www.clinicaltrials.gov ; Unique identifier: NCT02623140.

Objectives We evaluated the diagnostic performance of quantitative flow ratio (QFR) assessment of nonculprit lesions (NCLs) based on acute setting angiograms obtained in patients with ST‐segment elevation myocardial infarction (STEMI) with QFR, fractional flow reserve (FFR), and instantaneous wave‐free ratio (iFR) in the staged setting as reference. Background QFR is an angiography‐based approach for the functional evaluation of coronary artery lesions. Methods This was a post‐hoc analysis of the iSTEMI study. NCLs were assessed with iFR in the acute setting and with iFR and FFR at staged (median 13 days) follow‐up. Acute and staged QFR values were computed in a core laboratory based on the coronary angiography recordings. Diagnostic cut‐off values were ≤0.80 for QFR and FFR, and ≤0.89 for iFR. Results Staged iFR and FFR data were available for 146 NCLs in 112 patients in the iSTEMI study. Among these, QFR analysis was feasible in 103 (71%) lesions assessed in the acute setting with a mean QFR value of 0.82 (IQR: 0.73–0.91). Staged QFR, FFR, and iFR were 0.80 (IQR: 0.70–0.90), 0.81 (IQR: 0.71–0.88), and 0.91 (IQR: 0.87–0.96), respectively. Classification agreement of acute and staged QFR was 93% (95%Cl: 87–99). The classification agreement of acute QFR was 84% (95%CI: 76–90) using staged FFR as reference and 74% (95%CI: 65–83) using staged iFR as reference. Conclusions Acute QFR showed a very good diagnostic performance with staged QFR as reference, a good diagnostic performance with staged FFR as reference, and a moderate diagnostic performance with staged iFR as reference.