Inclusion Criteria:
1. Age 40-85 years;
2. Patients with recent hospitalization for documented ACS (the index event occurring 30-90 days before randomization) and meeting all of the following:
1. During the index hospitalization, patients underwent either PCI or diagnostic coronary angiography alone,
2. At least one non-culprit coronary lesion with 30%-70% diameter stenosis by visual estimation on coronary angiography,
3. Clinically stable throughout the screening period,
4. Receiving standard of care therapy for ACS in accordance with national guidelines,
5. Peripheral blood DNA available for targeted sequencing, with results demonstrating either TET2-CHIP or no CHIP-associated variants;
3. Written informed consent.
Exclusion Criteria:
1. Prior PCI or coronary artery bypass grafting (CABG) before documented ACS;
2. Other clinically significant cardiovascular diseases, including moderate-to-severe valvular heart disease (moderate or severe), heart failure (NYHA class III-IV), or atrial fibrillation;
3. Non-culprit coronary anatomy (e.g., marked tortuosity, bifurcation lesions, or small vessels \<1.5 mm in diameter) deemed to preclude plaque assessment by CCTA;
4. Planned PCI or CABG;
5. Abnormal liver function (ALT \>3 times the upper limit of normal range) at randomization;
6. Abnormal renal function (serum creatinine \>1.5 times the upper limit of normal range or estimated eGFR \<45 mL/min/1.73 m²) at randomization;
7. Hematologic abnormalities: anemia (hemoglobin \<100g/L), thrombocytopenia (platelet count \<100×109/L) or leukopenia (white blood cell \<3×109/L) at randomization;
8. Inflammatory bowel disease (Crohn's or ulcerative colitis) or active diarrhea;
9. Symptomatic peripheral neuropathy, pre-existing progressive neuromuscular disease or creatine kinase (CK) level \> 3 times the upper limit of normal range as measured within the past 30 days and determined to be non-transient through repeat testing;
10. Pregnancy, breastfeeding, or women of childbearing potential who are not using an effective method of contraception;
11. Any contraindication, known allergy or intolerance to colchicine;
12. Colchicine use within 30 days prior to randomization, or planned colchicine therapy for other indications;
13. Current or planned use of any of cyclosporine, verapamil, HIV protease inhibitors, azole antifungals, or macrolide antibiotics;
14. Existing or planned treatment with other anti-inflammatory or immunosuppressive drugs;
15. History of malignancy (hematologic or solid-tumor);
16. History of transplantation (hematopoietic stem cell or solid-organ);
17. Significant radiation exposure (≥40 mSv) within the past 12 months;
18. Known hypersensitivity to iodinated contrast media or uncontrolled active hyperthyroidism;
19. Current enrollment in another clinical trial;
20. A predicted life expectancy \< 1 year;
21. Any other circumstances in which the investigator judges that the patient is not suitable to participate in the clinical trial.
