The aim of this clinical trial is to explore the optimal preventative treatment strategy for non-flow-limiting vulnerable plaques. The main question it aims to answer is: Can interventional therapy further improve the outcome of non-flow-limiting vulnerable plaques on top of optimal pharmacologic therapy? Researchers will randomly assign patients who meet the inclusion criteria to preventative intervention plus optimal drug therapy (experimental group) or optimal drug therapy alone (control group). Participants will: Assigned to the control group: optimized drug therapy consisting of lifestyle improvement and intensive drug therapy including high-dose statin or other therapy to achieve target levels (low-density lipoprotein cholesterol \<1.4 mmol/L and decreased by 50% compared to the baseline). Lifestyle improvement and risk factor management included smoking cessation, nutritional optimization, physical activity, compliance with prescribed medications, and control of diabetes and hypertension. Assigned to the experimental group: all non-flow-limiting vulnerable plaques were treated with conventional second-generation drug-eluting stents. After the procedure, participants received dual antiplatelet therapy for about 12 months as well as other medications in the control group.