QFR in clinical practice: raising the bar for quality and reproducibility

The emergence of angiography-based physiology represents one of the most important advances in contemporary interventional cardiology. Quantitative flow ratio (QFR) was introduced with great promise: a rapid, wire-free, and hyperaemia-free method to extend the reach of functional coronary assessment. By lowering the barriers associated with pressure wires and pharmacological agents, QFR was envisioned as a pragmatic solution to the persistent underuse of physiology in daily practice. Early studies demonstrated good diagnostic accuracy and outcomes with QFR, leading to its inclusion in the European Society of Cardiology (ESC) guidelines as a Class I-recommended approach for guiding revascularisation1.

The results of the FAVOR III Europe trial, however, delivered a reality check2. When deployed across 34 centres in routine practice, a QFR-guided strategy resulted in higher revascularisation rates and failed to meet non-inferiority to fractional flow reserve (FFR) for clinical outcomes. This unexpected finding raised a fundamental question: were the limitations inherent to the QFR algorithm itself or to its application at the point of care?

In this issue of EuroIntervention, Kristensen et al discuss the REPEAT-QFR substudy, which provides the first comprehensive...