Key result
QFR-guided strategy fails non-inferiority to FFR, increasing major adverse cardiac events by ~63%.
Why the study?
Fractional flow reserve (FFR) and quantitative flow ratio (QFR) are diagnostic methods for assessing intermediate coronary stenosis, but it is uncertain whether QFR yields non-inferior 12-month clinical outcomes compared with FFR.
Does a QFR-guided diagnostic strategy yield non-inferior 12-month clinical outcomes compared with an FFR-guided strategy in patients with intermediate coronary stenosis?
RCT (n=2,000)
Open-label
1:1
Yes
Does a QFR-guided diagnostic strategy yield non-inferior 12-month clinical outcomes compared with an FFR-guided strategy in patients with intermediate coronary stenosis?
Hazard Ratio: 1.63 (95% CI 1.11–2.41)
Absolute Event Rate: 6.7% vs 4.2%
Captured external expert commentary on this paper, strongest first. Original sources are linked where available.
“This recommendation is surprising and needs to be revised for two main reasons. The first is that pressure wire-derived physiology is the reference standard for assessing intermediate stenoses, and QFR, at the time of this recommendation, had not been shown to be equivalent. Moreover, just recently the FAVOR III Europe Trial, which randomised 2,000 patients with at least one intermediate stenosis to either pressure wire-derived FFR-guided assessment or QFR-guided assessment, was published, demonstrating a significantly higher rate of the composite of death, myocardial infarction or ischaemia-driven revascularisation at one year in the QFR-guided arm. Based on these inferior results for QFR, there is no longer evidence or general agreement that QFR is beneficial, useful and effective in this particular setting (the definition of a Class I indication).”
“The lower QFR values led to 21% more patients receiving study lesion revascularization [and] a 27% increase in the number of stents implanted in these lesions.”
“Among 1,122 deferred patients, QFR deferral was associated with a higher 1-year major adverse cardiac events rate (5.6%) versus FFR (2.8%; adjusted hazard ratio [HR] 2.07, 95% confidence interval: 1.07-4.03; p=0.03). Target vessel failure was also higher with QFR (3.7% vs 1.8%; HR 2.27; p=0.049). Outcomes were primarily driven by unplanned revascularisations in the QFR group. While invasive FFR demonstrated low 1-year event rates (<3%), the performance of QFR challenges its reliability as a substitute for FFR in PCI deferral decisions.”
A QFR-guided revascularisation strategy failed to demonstrate non-inferiority to an FFR-guided strategy for 12-month clinical outcomes in patients with intermediate coronary stenosis.
BACKGROUND Fractional flow reserve (FFR) or non-hyperaemic pressure ratios are recommended to assess functional relevance of intermediate coronary stenosis. Both diagnostic methods require the placement of a pressure wire in the coronary artery during invasive coronary angiography. Quantitative flow ratio (QFR) is an angiography-based computational method for the estimation of FFR that does not require the use of pressure wires. We aimed to investigate whether a QFR-based diagnostic strategy yields a non-inferior 12-month clinical outcome compared with an FFR-based strategy. METHODS FAVOR III Europe was a multicentre, randomised, open-label, non-inferiority trial comparing a QFR-based with an FFR-based diagnostic strategy for patients with intermediate coronary stenosis. Enrolment was performed in 34 centres across 11 European countries. Patients aged 18 years or older with either chronic coronary syndrome or stabilised acute coronary syndrome, and with at least one intermediate non-culprit stenosis (40-90% diameter stenosis by visual estimate; referred to here as a study lesion), were randomly assigned (1:1) to the QFR-guided or the FFR-guided group. Randomisation was done using a concealed web-based system and was stratified by diabetes and presence of a left anterior descending coronary artery study lesion. The primary endpoint was a composite of death, myocardial infarction, and unplanned revascularisation at 12 months. The predefined non-inferiority margin was 3·4% and the primary analysis was performed in the intention-to-treat population. The trial was registered with ClinicalTrials.gov (NCT03729739) and long-term follow-up is ongoing. FINDINGS Between Nov 6, 2018, and July 21, 2023, 2000 patients were enrolled and randomly assigned to the QFR-guided strategy (1008 patients) or the FFR-guided strategy (992 patients). The median age was 67·3 years (IQR 59·9-74·7); 1538 (76·9%) patients were male and 462 (23·1%) were female. Median follow-up time was 365 days (IQR 365-365). At 12 months, a primary endpoint event had occurred in 67 (6·7%) patients in the QFR group, and in 41 (4·2%) patients in the FFR group (hazard ratio 1·63 [95% CI 1·11-2·41]). The event proportion difference was 2·5% (90% two-sided CI 0·9-4·2). The upper limit of the 90% CI exceeded the prespecified non-inferiority margin of 3·4%. Therefore, QFR did not meet non-inferiority to FFR. A total of 18 (1·8%) patients in each group experienced an adverse procedural event, the most frequent being procedure-related myocardial infarction, which occurred in ten (1·0%) patients in the QFR group and seven (0·7%) in the FFR group. One patient in the QFR group died in relation to the index procedure. INTERPRETATION The results of the FAVOR III Europe trial do not support the use of QFR if FFR is available to guide revascularisation decisions in patients with intermediate coronary stenosis. This finding could have implications for current clinical guidelines recommending QFR for this purpose. FUNDING Medis Medical Imaging Systems and Aarhus University.
Journal, society, and media accounts. Useful signal, not independent expert judgment.
No takes yet. Share an insight, caveat, or question.
Andersen et al. (2024) conducted an RCT in Intermediate coronary stenosis (n=2,000). Quantitative flow ratio (QFR)-based diagnostic strategy vs. Fractional flow reserve (FFR)-based diagnostic strategy was evaluated on Composite of death, myocardial infarction, and unplanned revascularisation at 12 months (HR 1.63, 95% CI 1.11-2.41). A QFR-based diagnostic strategy failed to meet non-inferiority to an FFR-based strategy for death, MI, or unplanned revascularisation at 12 months (HR 1.63; 95% CI 1.11-2.41).
Synapse has enriched 5 closely related papers on similar clinical questions. Consider them for comparative context: