Even with standard treatments like statins, patients with coronary artery disease often face a residual risk of further heart events. This risk is largely driven by ongoing inflammation and unstable fatty plaques in the heart's blood vessels. Icosapent ethyl (IPE) is a highly purified prescription medication known to improve cardiovascular outcomes, but its detailed effects on the heart's structure and inflammation in everyday clinical practice need further exploration.

This study is a prospective, observational, real-world study designed to evaluate the effectiveness of IPE in patients with Acute Coronary Syndrome (ACS) or Chronic Coronary Syndrome (CCS). The study plans to enroll 420 patients who will be followed for 12 months. Based on their routine clinical prescriptions, participants will be grouped into a control group (receiving standard cardiovascular care, including statins) and an exposure group (receiving standard care plus IPE).

Throughout the 1-year follow-up, researchers will conduct regular blood tests and advanced heart imaging. The main goal is to determine if adding IPE to standard therapy leads to a more significant reduction in inflammation. Additionally, the study will observe how IPE affects the stability of coronary plaques and the healing process of ventricular remodeling in a real-world clinical setting.

Inclusion Criteria:

• Age 18 years and older, of any sex.

  • Definite diagnosis of chronic coronary syndrome (CCS) according to the Chinese Guidelines for the Diagnosis and Management of Patients with Chronic Coronary Syndrome, or acute coronary syndrome (ACS) according to the 2025 ACC/AHA/ACEP/NAEMSP/SACI Guideline for the Management of Acute Coronary Syndromes.
  • Laboratory evaluation showing fasting triglycerides (TG) >= 1.7 mmol/L.
  • Ability to fully understand the study purpose, voluntary participation, and provision of signed written informed consent.

Exclusion Criteria:

• Women who are planning a pregnancy, currently pregnant, or lactating.

  • Known hypersensitivity or allergic reaction to the active ingredient of icosapent ethyl (IPE) or any of its excipients (applicable to patients in the exposure cohort).
  • Diagnosed with major life-threatening conditions such as malignant tumors, end-stage lung disease, or advanced neurodegenerative diseases, with a life expectancy of less than 12 months.
  • Concurrent participation in any other interventional clinical trial involving investigational drugs or medical devices.
  • Any other condition or severe non-compliance that, in the judgment of the investigator, makes the patient unsuitable for enrollment in this study.

The study population consists of adult patients (aged 18 years and older) diagnosed with either acute coronary syndrome (ACS) or chronic coronary syndrome (CCS) who present to the cardiology inpatient wards or outpatient clinics of the participating medical centers. These are real-world patients who have elevated fasting triglyceride levels (>= 1.7 mmol/L) and are routinely receiving standard-of-care cardiovascular therapies, including statin therapy. Depending on their routine clinical prescriptions determined by their treating physicians, they are either receiving Icosapent ethyl (IPE) as an add-on therapy or continuing with standard of care alone.

De-identified individual participant data (IPD) that underlie the results reported in the primary publication, along with the study protocol and statistical analysis plan, will be shared.

Data will be available upon reasonable request to the Principal Investigator, beginning 6 months and ending 36 months following article publication.

To gain access, researchers must submit a methodologically sound proposal for secondary analysis or meta-analysis. The proposal will be reviewed by the study steering committee. If approved, data sharing will be strictly subject to a formal data-sharing agreement and must comply with the ethical regulations of the participating institutions. No specific IPD will be shared unconditionally.