This study aims to compare the clinical outcomes between routine use of potassium competitive acid blocker (P-CAB) and guideline-directed gastrointestinal (GI) protection strategy in patients with acute myocardial infarction (AMI) undergoing percutaneous coronary intervention (PCI) and being treated with dual antiplatelet therapy (DAPT).

This is a prospective, open-label, two-arm, randomized, multi-center trial. A total of 5,000 patients with acute myocardial infarction (AMI) undergoing percutaneous coronary intervention (PCI) and receiving dual antiplatelet therapy (DAPT) will be enrolled and randomized in a 1:1 ratio. Patients will be assigned to either the routine use of P-CAB group or the guideline-directed GI protection strategy group. The primary endpoint is the occurrence of Net Adverse Clinical Events (NACE), a composite of death from any causes, myocardial infarction, stroke, or Bleeding Academic Research Consortium (BARC) type 3-5 bleeding at 1 year.

Inclusion Criteria:

• Patients aged 19 years or older.
• Patients diagnosed with acute myocardial infarction (ST-segment elevation myocardial infarction [STEMI] or non-ST-segment elevation myocardial infarction [NSTEMI]).
• Patients who underwent percutaneous coronary intervention (PCI) with drug-eluting stents (DES) or drug-coated balloons (DCB).
• Patients (or their legal representatives) who understood the study risks and benefits and provided voluntary written informed consent.

Exclusion Criteria:

• History of hypersensitivity (e.g., allergic reaction, anaphylactic shock) or contraindication to study drugs (potassium-competitive acid blocker [P-CAB] or proton pump inhibitor [PPI]).
• Presence of active gastrointestinal bleeding.
• Pregnant or breastfeeding women.
• Non-cardiac life expectancy of less than 1 year or patients expected to have low compliance (as determined by the investigator's medical judgment).
• Patients who refuse to participate or are unable to follow the requirements specified in the study protocol.