QFR vs. FFR: Is Coronary Revascularization Deferral Safe? Results from a FAVOR III Sub-Analysis

In cases of intermediate coronary lesions, functional assessment is recommended to aid the decision-making process regarding revascularization. There are several tools currently used to that end, such as fractional flow reserve (FFR) and non-hyperemic coronary flow indices. The quantitative flow ratio (QFR) is an angiography-based method that estimates FFR values.

Several studies have validated the use of QFR to guide revascularization decisions in intermediate coronary lesions. However, in the recent randomized FAVOR III Europe trial, a QFR-based strategy did not meet non-inferiority criteria compared to FFR regarding the incidence of major adverse cardiac events (MACE). While deferring revascularization based on physiological factors has proven to be safe, the safety of this strategy with QFR specifically has not yet been established.

The aim of this sub-analysis of the FAVOR III Europe Study (a randomized and multicenter trial) was to assess the safety of revascularization deferral based on QFR compared to FFR.

The primary endpoint (PEP) was the one-year MACE rate, defined as a composite of all-cause death, acute myocardial infarction (AMI), or unplanned coronary revascularization. The secondary endpoint (SEP) included the individual components of the PEP and target vessel failure (TVF).

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The FAVOR III Europe Study included 2000 patients. Among them, 1008 were randomized to the QFR group and 992 to the FFR group. The mean age was 66 years, and most subjects were men. The most frequent clinical presentation was chronic coronary syndrome. A total of 523 patients (55.2%) in the QFR group and 599 patients (65.3%) in the FFR group had at least one deferred revascularization. Of these, 433 patients (82.8%) in the QFR group and 511 (85.3%) in the FFR group had complete deferred revascularization of all lesions.

In the group of patients with complete deferred revascularization, the MACE rate was significantly higher in the QFR group compared to the FFR group (24 [5.6%] versus 14 [2.8%]; hazard ratio [HR] 2.07; 95% confidence interval [CI]: 1.07-4.03; p=0.03). In the subgroup with at least one deferred lesion, the MACE rate was 5.6% versus 3.6%, respectively (HR 1.55; 95% CI: 0.88-2.73; p=0.13).

Conclusion

In this sub-analysis, QFR-based coronary revascularization deferral was associated with a higher MACE rate compared to the FFR-based strategy. This difference was mainly due to a higher number of unplanned revascularizations.

Original Title: Coronary revascularisation deferral based on quantitative flow ratio or fractional flow reserve: a post hoc analysis of the FAVOR III Europe trial.

Reference: Birgitte K. Andersen MD et al EuroIntervention 2025;21:e1-e10.