A Prospective Multicenter Real-World Registry of Quantitative Flow Ratio-Guided Coronary REvascularization and QuAlity evaLuation

This is a prospective, multicenter, observational registry study conducted at more than 50 centers across China. Patients with coronary angiography showing visually estimated at least one main branch stenosis ≥50% who undergo PCI or receive conservative treatment for acute coronary syndrome (including unstable angina, non-ST-segment elevation myocardial infarction, and ST-segment elevation myocardial infarction >4 weeks after onset) or chronic coronary syndrome (including stable angina and asymptomatic myocardial ischemia) will be consecutively enrolled. Coronary angiographic images will be submitted to an independent core laboratory for retrospective QFR analysis. The study will establish a QFR-based quality control standard system for coronary revascularization.

Prespecified subgroup analyses will be performed to assess the concordance rates, overtreatment, and undertreatment rates between clinical decisions and offline core laboratory QFR, and to explore heterogeneity across hospital levels, clinical presentations, disease complexity, target vessel, operator annual PCI volume, QFR image analyzability, and lesion morphology. Other prespecified subgroups will be analyzed for the primary and secondary endpoints, including age, sex, diabetes, smoking status, acute coronary syndrome, body mass index, left ventricular ejection fraction, lesion location, length and reference vessel diameter, stenosis severity, multivessel disease, calcified lesion, bifurcation, tandem and bending/tortuous lesion, QFR gray zone (0.75-0.85), QFR based functional and residual functional SYNTAX score, residual QFR, center experience for invasive physiology, and learning experience with QFR.

Inclusion criteria

• Age ≥18 years
• Coronary angiography showing visually estimated at least one main branch coronary stenosis ≥50% in patients with acute coronary syndrome (including unstable angina, non-ST-segment elevation myocardial infarction, and ST-segment elevation myocardial infarction >4 weeks after onset) or chronic coronary syndrome (including stable angina and asymptomatic myocardial ischemia) who undergo PCI or receive conservative treatment
• Ability to understand the study design and provide written informed consent

Exclusion criteria

• ST-segment elevation myocardial infarction within 4 weeks of onset
• History of coronary artery bypass grafting (CABG) or planned CABG within 6 months
• Inability to undergo coronary angiography
• Non-cardiac cause with expected survival <1 year
• Other conditions that may interfere with follow-up (e.g., dementia, substance abuse including drug addiction and other drug dependencies)
• Refusal to participate in the study