The overall purpose of the FAVOR III China trial is to investigate if a strategy of quantitative flow ratio (QFR)-guided percutaneous coronary intervention (PCI) yields superior clinical outcome and cost-effectiveness compared to a strategy of standard coronary angiography-guided PCI in evaluation of patients with coronary artery disease.

The FAVOR III China is a prospective, multicenter, blinded, randomized, superiority clinical trial comparing the clinical outcome and cost-effectiveness of the two PCI strategies, QFR-augmented angiography-guided (QFR-guided) strategy versus an angiography-only-guided (angiography-guided) strategy , in evaluation of patients with coronary artery disease (CAD). The study is adequately powered to detect if the primary outcome by the QFR-guided PCI strategy is superior to the standard angiography-guided PCI strategy. The hypothesis is that a QFR-guided PCI strategy results in superior clinical outcome, assessed by rate of Major Adverse Cardiac Events (MACE) defined as a composite of all-cause mortality, any myocardial infarction (MI) and any ischemia-driven revascularization at 1 year, compared to a standard angiography-guided PCI strategy. If QFR-guided strategy is shown to be superior to the angiography-guided strategy, the lower clinical costs and better clinical outcome by QFR may suggest it to be the preferred strategy for invasive functional evaluation of coronary artery stenosis.

The primary and major secondary endpoints will be analyzed in prespecified subgroups, 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.

For the purpose of protecting trial subjects and study personnel while maintaining trial data integrity during the coronavirus disease 2019 (COVID-19) pandemic, we particularly arranged an unscheduled telephone follow-up for all the participants, to evaluate the potential impact of the pandemic. Using a special designed follow-up questionnaire, all subjects were required to report the presence of COVID-19 infection and its related complications, any possible ischemia symptom, any hospitalization or outpatient visit, and interruption of cardiovascular medicine during this time (from Jan 20, 2019 to May 1, 2020). Clinical event committees (CEC) will update the working protocol to enable the re-adjudication of events from the onset of the pandemic to the end of the trial. All the events will be classified as related, possibly related, or not related to COVID-19 infection. To identify the interaction between COVID-19 pandemic and randomized revascularization strategy in the current study, several prespecified subsets will be added to the subgroups analysis, including COVID-19 positive vs. negative subjects, pre-pandemic vs. during pandemic vs. post-pandemic subjects, and the sites located at the high-risk region vs. low- to mediate-risk region.

Inclusion Criteria:

General inclusion criteria:

• Age ≥ 18 years
• Stable or unstable angina pectoris, or post-acute myocardial infarction (≥ 72 hrs)
• Signed written informed consent
• Eligible for PCI by the operators

Angiographic inclusion criteria:

• At least one lesion is present of DS% ≥50% and ≤90% in one major native epicardial coronary artery and supplying viable myocardium
• Reference lumen diameter ≥ 2.5mm by visual assessment

Exclusion Criteria:

General exclusion criteria:

• Cardiogenic shock or severe heart failure (NYHA ≥III)
• Severely impaired renal function: creatinine > 150μmol/L or Cockcroft-Gault calculated GFR < 45 ml/kg/1.73 m2
• Allergy to iodine-containing contrast agents
• Pregnancy or intention to become pregnant during the course of the trial
• Life expectancy less than one year

Angiographic exclusion criteria:

• With only one coronary artery lesion（DS%>90%）with TIMI flow < 3
• Target stenoses are culprit lesions related with acute myocardial infarction
• Target stenoses in the vessel involving myocardial bridge
• Poor angiographic image quality precluding vessel contour detection or with suboptimal contrast filling
• Severe overlap in the stenosed segment or severe tortuosity of any target vessel deemed unable for QFR measurement

This is a blinded clinical trial. Subjects and clinical assessor will be blinded to the assignment results. All the study site personnel will receive training for the blinding measures before the trial initiating. In addition to standard procedural sedation, music-playing headphones will be worn by the patient during the whole procedure, and patients in both groups will be preset a 10 minutes delay for QFR calculation before the PCI procedure, a lesion/device evaluation form is required to fill in during the period in both groups, to reduce the possibility of unblinding. All the study site personnel will be trained not to disclose the treatment assignment to the subject in any unplanned time. Subject blinding should be maintained until the one-year follow-up visit for all registered subjects is completed.