The overall purpose of Flash FFR Ⅱ is to investigate whether coronary angiography-derived fractional flow reserve (caFFR), compared with fractional flow reserve (FFR) measured by a pressure wire, has non-inferior clinical effect and cost benefit in guiding the percutaneous coronary intervention (PCI) for patients with moderate coronary artery stenosis in terms of long-term clinical prognosis.

Flash FFR Ⅱ is a prospective, multicenter, blinded, randomized, non-inferiority trial. Eligible patients with moderate coronary artery stenosis will be included in the study and randomly assigned to either caFFR-guided group or FFR-guided group. Participant caFFR or FFR will be used to guide percutaneous coronary intervention (PCI) strategy.

The rate of major cardiovascular adverse events (MACE) and the cost data will be collected during the long-term follow-up (2 years). MACE is defined as a composite of all-cause death, myocardial infarction (MI), unplanned revascularization. Clinical outcomes and cost-effectiveness will be compared between the two groups.

A subgroup analysis is pre-set and included in the protocol, including age, sex, body mass index, diabetes mellitus, smoking status, mean aortic pressure (resting state), acute coronary syndrome, left ventricular ejection fraction, lesion site, lesion stenosis severity, target vessel reference diameter, small vessel lesion, blood flow velocity, PCI mode, and so on.

The trial is equipped with a core laboratory. Some interesting sub-studies will be carried out, such as a comparison of laboratory and operator analysis results.

If the trial results show non-inferiority, it should be noted that caFFR can bring new benefits to both operators and patients as a new index of physiological assessment of coronary artery stenosis severity with the advantages of lower cost, less risk, faster time, and less use of resources.

Inclusion Criteria:

• General inclusion criteria:

  1. Age above 18 years old, no limit on the gender;
  2. Angiography is considered necessary and feasible by investigator, and PCI will be performed if necessary;
  3. Suspected coronary heart disease, stable angina pectoris, unstable angina pectoris, non-culprit vascular assessment in participants with acute non-ST-segment elevation myocardial infarction, and non-culprit vascular assessment in patients with previous ST-segment elevation acute myocardial infarction;
  4. Participants voluntarily participate in this clinical trial and sign informed consent form.

• Coronary angiography inclusion criteria:

The presence of at least one stenosis and meets the following imaging findings:

1. The degree of coronary artery stenosis≥50% and ≤90% by visual measurement;
2. The reference diameter of the stenotic segment≥2.25 mm by visual measurement;
3. The investigator visually observes the target vessel through angiographic images, and consider that PCI surgery is technically feasible.

Exclusion Criteria:

• General exclusion criteria:

  1. Acute ST-segment elevation myocardial infarction within 6 days;
  2. Cardiogenic shock or left ventricular ejection fraction≤50%;
  3. eGFR < 30 mL/min (1.73 m2);
  4. Severe coagulation dysfunctions or bleeding disorders;
  5. Allergic to iodine contrast medium or contraindications for adenosine administration;
  6. Severe aortic stenosis;
  7. Life expectancy less than 1 year;
  8. Pregnant women or women planning a recent pregnancy;
  9. Participation in any other clinical trials of devices or drugs (ongoing or within the past 1 month);
  10. The investigator believes that the particitant has other conditions that are not suitable for clinical trials.

• Coronary angiography exclusion criteria:

  1. TIMI flow in the target vessel\

In the Flash FFR II study, clinical outcome assessors (including the follow-up research personnel, clinical events committee (CEC), data and safety monitoring board (DSMB), and core laboratory) will be blinded to randomization arm. The data safety monitoring board (DSMB) may request unblinding of grouping information due to patient safety reasons. All the study site personnel will receive training for the blinding requirements before the trial initiating to prevent disclosure of random assignment to the follow-up personnel in any unplanned way.