The Flash FFR Ⅱ Study

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 beperformed if necessary;
3. Suspected coronary heart disease, stable angina pectoris, unstable anginapectoris, non-culprit vascular assessment in participants with acutenon-ST-segment elevation myocardial infarction, and non-culprit vascularassessment in patients with previous ST-segment elevation acute myocardialinfarction;
4. Participants voluntarily participate in this clinical trial and sign informedconsent 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, andconsider 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 adenosineadministration;
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 withinthe past 1 month);
10. The investigator believes that the particitant has other conditions that are notsuitable for clinical trials.

• Coronary angiography exclusion criteria:

1. TIMI flow in the target vessel<grade III ;
2. Presence of myocardial bridge and systolic compression ≥50% in the target vessel;
3. Presence of artificial bypass in the target vessel;
4. Left main coronary artery or right coronary artery ostial lesions;
5. Stent implantation in the target vessel within 3 months;
6. Target vessel provides collateral support to chronically total occluded vessels;
7. Presence of factors affecting angiographic analysis and stenosis visualization,including incomplete vessel opacification, or overlap with other coronarybranches of extreme vessel foreshortening.