Inclusion Criteria:  General Inclusion Criteria:  Over 18 years old; Be able to understand the purpose of the test and sign the informed consent form; Previous intracoronary stent implantation; According to the comprehensive clinical evaluation, coronary angiography and FFR were proposed;  CTA image Inclusion Criteria:  The coronary CT angiography images showed that the reference vessel diameter of the stenosis segment in the stent was ≥ 2mm; The stenosis degree of coronary stent diameter ≥ 30% and ≤ 90% by visual inspection.  Exclusion Criteria:  General exclusion criteria:  Previous coronary artery bypass grafting (CABG), artificial heart valve implantation, pacemaker or implantable defibrillator implantation; There are persistent or active symptoms of clinical instability, including acute chest pain (sudden onset), cardiogenic shock, unstable blood pressure state (systolic blood pressure less than 90 mmHg), severe congestive heart failure (NYHA cardiac function grade III or IV) or acute pulmonary edema; Acute myocardial infarction occurred within 7 days before enrollment; Patients with other severe diseases are not suitable for clinical trials, such as complex congenital heart history, sick sinus syndrome, long QT syndrome, severe arrhythmia or tachycardia, severe asthma, severe or very severe chronic obstructive pulmonary disease, chronic renal function impairment (serum creatinine value > 1.5 mg / dL or creatinine clearance rate < 45ml / kg · 1.73m2); There are contraindications to the use of disodium adenosine triphosphate; Allergic to iodized contrast media; Pregnancy or unknown pregnancy status; The expected life is less than 2 months; There are any other factors that the researchers believe are not suitable for inclusion or completion of this study.  CTA image exclusion criteria:  The coronary artery image was obviously misplaced; Coronary artery occlusion.