A Study Evaluating the Vascular Healing and Neointimal Transformation at 1 Month After Implantation of BioFreedom™ Drug-coated Stents and the Xience Drug-eluting Stent System in Patients With Acute Coronary Syndrome and High Bleeding Risk Using Optical Coherence Tomography

Inclusion criteria

• Age ≥18 years
• Male or non-pregnant female
• Acute coronary syndrome (ACS) patients requiring percutaneous coronary intervention (PCI)
• No contraindications for coronary artery bypass grafting (CABG)
• High bleeding risk (HBR) patients per ARC-HBR definition (meeting ≥1 major or 2 minor criteria):

Major Criteria:

• Expected long-term oral anticoagulation
• Severe/end-stage chronic kidney disease (eGFR <30 mL/min)
• Moderate/severe anemia (Hb <110 g/L)
• Spontaneous bleeding requiring hospitalization/transfusion within 6 months (or recurrent)
• Chronic bleeding diathesis
• Moderate/severe thrombocytopenia pre-PCI (platelet count <100×10⁹/L)
• Liver cirrhosis with portal hypertension
• Active malignancy in past 12 months (excluding non-melanoma skin cancer; defined as diagnosis/treatment within 12 months)
• History of spontaneous intracranial hemorrhage
• Traumatic intracranial hemorrhage within 12 months
• Known cerebral arteriovenous malformation
• Moderate/severe ischemic stroke within 6 months
• Major surgery/severe trauma within 30 days pre-PCI
• Planned non-deferrable major surgery during dual antiplatelet therapy

Minor Criteria:

• Age ≥75 years
• Moderate chronic kidney disease (eGFR:30~59 ml/min)
• Mild anemia (male: Hb=110~129 g/L; female: Hb=110~119 g/L)
• Spontaneous bleeding requiring hospitalization/transfusion within 6-12 months pre-PCI
• Chronic NSAID/steroid use post-PCI
• Ischemic stroke >6 months pre-PCI
• Capable of understanding trial objectives and providing informed consent

Angiographic Inclusion Criteria:

• Target lesion must be primary native coronary artery lesion
• Target lesion with ≥70% diameter stenosis (visual estimate), or 50-70% diameter stenosis (visual estimate) with ischemic evidence
• ≥1 non-target lesion requiring intervention
• Non-target lesions eligible for elective treatment within 1 month

Exclusion criteria

General Exclusion Criteria:

• Presence of ≥1 evidence of heart failure including:

• NYHA Class III or higher, or
• Killip classification ≥ Grade 2, or
• Left ventricular ejection fraction (LVEF) ≤30% within 30 days pre-procedure (by echocardiography or intraoperative ventriculography)
• Cardiogenic shock patients
• Known allergies to: Aspirin / clopidogrel / ticagrelor / heparin, Contrast agents/drugs used in drug-eluting stents or contraindications to aspirin/ clopidogrel / ticagrelor
• Life expectancy <12 months or factors potentially compromising clinical follow-up
• Participation in other drug/medical device trials prior to enrollment without reaching primary endpoint timelines
• History of substance abuse (alcohol/cocaine/heroin, etc.)
• Severe arrhythmias (e.g., high-risk ventricular premature contractions/ ventricular tachycardia)
• Other medical conditions deemed unsuitable by investigators

Angiographic Exclusion Criteria:

• Left main coronary artery disease
• Bypass graft lesions
• Evidence of extensive thrombus in target vessel