1 or 6 Months of Dual Antiplatelet Therapy After Drug-coated Balloon Angioplasty for De-novo Small Coronary Artery Disease

Inclusion Criteria: * 1)Adults aged 19 years or older 2)Subjects who have undergone drug-coated balloon (DCB) angioplasty 3) Subjects with stable angina, asymptomatic ischemia, and angiographically confirmed coronary lesions 4)Patients who have not undergone coronary intervention and whose coronary angiography demonstrates a reference vessel diameter between 2.0 mm and 3.0 mm, meeting all of the following conditions: No severe dissection corresponding to National Heart, Lung, and Blood Institute (NHLBI) grade C to F No reduction in coronary blood flow defined as TIMI flow grade \< 2 No residual stenosis ≥ 30% 5)Patients newly diagnosed with small-vessel coronary artery disease among those maintained on single antiplatelet therapy (SAPT) for at least 6 months after undergoing: de novo percutaneous coronary intervention (de novo PCI),in-stent restenosis PCI (ISR PCI), or percutaneous transluminal coronary angioplasty (PTCA) 6)Subjects who voluntarily agree to participate in this clinical study and provide written informed consent Exclusion Criteria: * 1\) Patients diagnosed with Acute Coronary Syndrome (ACS), including STEMI, NSTEMI, or Unstable Angina. 2\) Patients undergoing concomitant Percutaneous Coronary Intervention (PCI) during the Drug-Coated Balloon (DCB) procedure. 3\) Patients undergoing PCI for In-Stent Restenosis (ISR). 4) Patients with a diagnosis of active bleeding or coagulation disorder within 2 months prior to obtaining informed consent. 5\) Patients who underwent surgery with moderate-to-high risk within 6 weeks prior to obtaining informed consent. 6\) Patients with a history of intracerebral hemorrhage (ICH). 7) Patients with Hemoglobin \< 10 g/dL or Platelet count \< 100 x 10³/mm³. 8) Patients unable to discontinue oral anticoagulation therapy (OAC). 9) Patients on long-term treatment with NSAIDs or COX-2 inhibitors (excluding aspirin). 10\) Patients with a life expectancy of less than 1 year due to malignancy or other comorbidities. 11\) Patients with moderate-to-severe hepatic impairment. 12) Patients at risk of symptomatic bradycardia (e.g., 2nd-degree Mobitz Type II block or 3rd-degree AV block). 13\) Patients with dyspnea, such as those with Chronic Obstructive Pulmonary Disease (COPD). 14\) Patients with intolerance or hypersensitivity to the investigational medicinal products. 15\) Patients who participated in other clinical trials within 3 months prior to informed consent (excluding non-interventional observational studies). 16\) Women who are pregnant or breastfeeding. 17) Patients with End-Stage Renal Disease (ESRD) on hemodialysis or peritoneal dialysis, or those who have undergone a kidney transplant. 18\) Patients with rare hereditary metabolic disorders, such as galactose intolerance, Lapp lactase deficiency, or glucose-galactose malabsorption. 19\) Any patient deemed unsuitable for participation in the clinical trial at the investigator's discretion.