FAVOR III Europe Trial of QFR-based Diagnostic Strategy Fails to Meet Primary Endpoint

October 30, 2024—Results from the FAVOR III Europe trial demonstrated that clinical outcomes at 1 year follow-up of a quantitative flow ratio (QFR)–guided diagnostic strategy did not meet noninferiority compared to a standard fractional flow reserve (FFR)–guided strategy in patients with intermediate coronary stenosis.

The FAVOR III Europe trial findings were reported at TCT 2024, the 36th annual Transcatheter Cardiovascular Therapeutics annual scientific symposium of the Cardiovascular Research Foundation held October 27-30 in Washington, DC. Simultaneously, the data were published by Birgitte Krogsgaard Andersen, MD, et al in The Lancet. The study was funded in part by Medis Medical Imaging Systems and Aarhus University in Aarhus, Denmark.

As noted in the TCT press release, QFR is diagnostic tool that estimates FFR based on computer analysis of coronary angiographic images without the need for a pressure wire. Current society guidelines recommend FFR or instantaneous wave-free ratio for invasive functional evaluation of intermediate coronary stenosis.

FAVOR III Europe was a randomized, multicenter, noninferiority trial comparing the strategies.

As summarized by TCT, the study was composed of 2,000 patients enrolled at 34 heart centers in Europe. The patients had either stable angina pectoris or acute coronary syndrome and had an indication for assessment of at least one intermediate coronary stenosis.

The patients were randomized to the QFR-guided strategy (1,008 patients) or the FFR-guided strategy (992 patients). Baseline characteristics were similar between both groups.

The most common indication for invasive coronary angiography in the trial was chronic coronary syndromes in 655 patients (66.8%) in the QFR group, and 645 patients (67.1%) in the FFR group. Revascularization was performed if QFR or FFR were ≤ 0.8.

The primary endpoint was major adverse cardiovascular events (MACE, a composite of death, myocardial infarction, and unplanned revascularization) at 12 months. All events were adjudicated by an independent clinical endpoint committee blinded to the assigned group.

MACE occurred in 6.7% of the QFR group versus 4.2% of the FFR group (hazard ratio [HR], 1.63; 95% CI, 1.11-2.41; P = .013). Noninferiority was not met.

Secondary endpoints for QFR versus FFR included the following:

• All-cause mortality—1.4% versus 1.1% (HR, 1.25; 95% CI, 0.57-2.76; P = .58)
• Myocardial infarction—3.7% versus 2.0% (HR, 1.84; 95% CI, 1.07-3.17; P = .028)
• Unplanned revascularization—3.3% versus 2.5% (HR, 1.36; 95% CI, 0.81-2.30; P = .25)
• Target vessel failure—5.0% and 3.6% (HR, 1.42; 95% CI, 0.92-2.19; P = .11).

“Mainly driven by higher rates of myocardial infarction and unplanned revascularization, a QFR-guided revascularization strategy did not meet noninferiority compared to a standard FFR-guided strategy for clinical outcomes at 1 year,” commented Niels Ramsing Holm, MD, who is from Aarhus University Department of Clinical Medicine, Aarhus University Hospital Department of Cardiology, Research, commented in the press TCT press release. “Additionally, use of QFR for decision-making was associated with a higher number of lesions treated than with an FFR-guided strategy.”