To evaluate and compare the change of plaque composition by VH-IVUS imaging in subjects who take NXT and placebo in post-PCI of AMI patients during 12 months follow-up.

NXT-ASSESS is a placebo controlled,double-blind,randomised trial for assessment of the efficacy of Naoxingtong capsules in the treatment of coronary atherosclerotic plaque in patients with acute myocardial infarct on the basis of optimal medical therapy.A total of approximately 80 AMI patients with selective PCI indication who take NXT and placebo in post-PCI 12 months

Inclusion Criteria:

1. Signing informed consent;
2. Male or female aged 18 to 75 years old;
3. AMI patients with selective PCI indication primary PCI patients are exclusive;
4. No history of CABG or PCI;

Image inclusion criteria:

1. CCTA at least one in-segment ≥20% and ≤70% diameter stenosis non-culprit vessel in the proximal-middle segments of RCA, LCX, LAD (the proximal and distal plaque within 5mm, same as below);
2. Radiography diameter of target vessel, 2.5-4.0mm;
3. Studied vessel can be evaluated with OCT and IVUS; OCT: the visual target study lesion is lipid-rich plaque with lipid arc≥100 degree and fiber cap thickness≤120µm.

Exclusion Criteria:

1. Life expectancy is less than 1 year;
2. Cannot implant drug stent;
3. Received ≥4weeks systematic treatment of statin and other lipid-lowering drug in the 3 months before admission;
4. Received ≥4 weeks systematic treatment of any traditional Chinese medicine;
5. Known to have adverse reaction to ingredients of NXT capsule;
6. Patients with severe heart disease that CABG or selective PCI, heart transplantationSAVR/TAVR are required during the study(12 months);
7. LVEF<40%;
8. Drug uncontrollable recurrent and highly symptomatic arrhythmia such as ventricular tachycaidia, atrial fibrillation with rapid ventricular rate and paroxysmal supraventricular tachycardia in the 3 months before ACS admission;
9. Known any stroke;
10. Other operations arranged during the study period (12 months);
11. Uncontrollable hypertension, defined as resting systolic BP≥180mmHg;
12. Clinical confirmed as statin intolerance;
13. Type I diabetes or type 2 diabetes that is not well controlled;
14. Moderate and severe renal dysfunction (defined as eGFR<30ml/min/1.73m2);
15. Clinical confirmed liver disease or liver dysfunction (AST or ALT >3*ULN);
16. Clinical confirmed infection and other hematological, metabolic gastrointestinal or endocrine dysfunction that researchers believe not suitable for enrollment;
17. Known factors that may not be compliant, such as alcoholism, drug addiction, mental illness, etc.;
18. Participated in other clinical research projects, or within 30 days of the last participating clinical project;
19. Pregnant,breast feeding women or those plan to conceive during the study;
20. History of malignant tumor.

Lesion related:

1. Target segment severe calcification;
2. Failed PCI in culprit vessel;
3. Failed OCT screening (lipid arc/ fiber cap thickness does not match filter criteria);
4. Complications during the evaluation of OCT and IVUS/VH-IVUSOCT and IVUS/VH-IVUS evaluation failed due to instruments.