Aspirin 50mg vs 100mg Combined With P2Y12 Inhibitor After PCI

This is a randomized, open-label, active-controlled, non-inferiority clinical trial (the ASPIRE-LD trial) conducted in China. It aims to compare the efficacy and safety of low-dose aspirin (50 mg once daily) versus standard-dose aspirin (100 mg once daily), both in combination with a P2Y12 inhibitor, in patients who have successfully undergone percutaneous coronary intervention (PCI) and plan to receive at least 12 months of dual antiplatelet therapy (DAPT). A total of 2640 eligible patients will be randomly assigned in a 1:1 ratio to receive either 50 mg or 100 mg of enteric-coated aspirin daily, plus a P2Y12 inhibitor (ticagrelor 90 mg twice daily or clopidogrel 75 mg once daily, prescribed according to routine clinical practice). All participants will be followed for 12 months after randomization. The primary goal is to verify that 50 mg aspirin is non-inferior to the 100 mg standard dose in preventing major adverse cardiac and cerebrovascular events (MACCE: cardiovascular death, non-fatal myocardial infarction, definite/probable stent thrombosis, and ischemic stroke) at 12 months post-PCI. If non-inferiority is confirmed, the study will further test whether 50 mg aspirin reduces clinically relevant bleeding events (BARC type 2, 3, or 5) better than the standard dose. The study is sponsored by the First Hospital of Jilin University and will be carried out in 10-15 tertiary hospitals across China. Its findings will provide evidence for optimizing aspirin dosing in post-PCI DAPT.

Inclusion Criteria: * Aged 18 to 85 years at the time of screening * Diagnosed with acute coronary syndrome (ACS) or chronic coronary syndrome (CCS) * Has undergone successful percutaneous coronary intervention (PCI) with stent implantation * Planned to receive at least 12 months of dual antiplatelet therapy (DAPT) with aspirin plus a P2Y12 inhibitor after PCI * Able to provide written informed consent and comply with study follow-up requirements Exclusion Criteria: * Known hypersensitivity or contraindication to aspirin, P2Y12 inhibitors, or related excipients * High bleeding risk: history of intracranial hemorrhage, gastrointestinal bleeding within 6 months, active bleeding diathesis, or coagulopathy * Severe hepatic dysfunction (Child-Pugh class C) or severe renal impairment (eGFR \< 30 mL/min/1.73 m²) * Ischemic or hemorrhagic stroke within 3 months before enrollment * Pregnant or lactating women; women of childbearing potential unwilling to use effective contraception * Life expectancy \< 12 months due to other severe comorbidities such as advanced malignancy * Participation in another interventional clinical trial within 30 days before screening * Any other condition judged by the investigator to make the patient unsuitable for the study