The aim of this study was to investigate the accuracy of quantitative flow ratio (QFR) for predicting fractional flow reserve (FFR) ≤0.80 in an independent core laboratory.

FFR is an invasive physiological index used to define coronary stenosis that causes ischemia. Several studies have suggested that FFR-based percutaneous coronary intervention (PCI) can reduce adverse clinical outcomes compared to angiography-guided PCI. Although FFR is highly recommended in current guidelines, it is underused in real-world practice. QFR is a method for evaluating fractional flow reserve FFR without the use of an invasive coronary pressure wire or pharmacological hyperemic agent.

The aims of this study were:

1. To investigate diagnostic accuracy of angiography-based QFR for hemodynamic assessment of coronary artery stenosis compared to pressure wire-based FFR.
2. To compare the diagnostic performance of QFR versus % diameter stenosis (DS) in identifying physiologically significant coronary artery disease (CAD) using FFR as the reference standard.
3. To identify factors affecting QFR accuracy.
4. To compare the coronary CT data with QFR.

Inclusion Criteria:

• Patients suspected with CAD undergoing diagnostic coronary angiography with an indication for to perform invasive FFR

Exclusion Criteria:

• Suboptimal angiographic image quality for QFR analysis
• Primary myocardial or valvular disease
• Left ventricular ejection fraction ≤40%
• Patients with cardiogenic shock

Patients suspected with CAD undergoing diagnostic coronary angiography with an indication for to perform invasive FFR were included. Clinical exclusion criteria included cardiogenic shock, reduced ejection fraction (EF ≤40%), or suboptimal angiographic image quality for QFR analysis.

The sharing plan will be decided by the study committee.