In patients with subclinical coronary artery disease, the ASCAD-P study aims to assess the feasibility of a larger phase 3 pragmatic randomized controlled trial comparing prescription versus no prescription of low-dose aspirin in routine clinical practice.

Cardiovascular disease remains the leading cause of mortality worldwide. Recent large randomized trials have demonstrated limited net clinical benefit of aspirin in unselected primary prevention populations, leading to guideline recommendations against its systematic routine use for cardiovascular protection.

Patients with subclinical coronary artery disease represent a high-risk subgroup. These individuals have documented coronary artery disease but have not experienced overt cardiovascular events or undergone revascularization. Observational data suggest that this population carries a substantially increased risk of myocardial infarction compared with individuals without coronary atherosclerosis. However, the benefit-risk balance of aspirin in this intermediate-risk group remains uncertain

Primary Objective:

To evaluate the recruitment rate of a pilot randomized trial comparing low-dose aspirin prescription versus no prescription.

Secondary Objectives

To evaluate key feasibility metrics, including:

• The proportion of eligible patients who are randomized;
• Adherence and persistence to the assigned intervention at 12 months;
• The proportion of patients who do not complete the 12-month follow-up;
• Barriers to recruitment, adherence, and retention.

Exploratory Objectives:

To explore clinical outcomes at 12 months, including:

• The incidence of clinically significant bleeding events (BARC type 2, 3, or 5) and bleeding site;
• The incidence of major adverse cardiovascular events (MACE), defined as a composite of all-cause mortality, non-fatal myocardial infarction, non-fatal stroke, or coronary revascularization;
• Individual components of the composite endpoint;
• Cardiovascular mortality;
• Adverse Events and Serious Adverse Events.

Inclusion Criteria:

1. Documented coronary atherosclerosis, as defined by one of the following criteria:

   1. Coronary artery calcium (CAC) score > 0;
   2. Cardiac CT angiography (CCTA) / CoroScan: lesions <70% in the right coronary (RCA), left anterior descending (LAD), and circumflex (Cx) arteries or their branches, and <50% in the left main coronary artery;
   3. Coronary angiography: lesions <70% in the right coronary (RCA), left anterior descending (LAD), and circumflex (Cx) arteries or their branches, and <50% in the left main coronary artery; if performed, physiological coronary assessments (FFR, dPR, iFR, etc.) and intracoronary imaging (IVUS or OCT) must be negative for significant disease.

2. Willing and able to provide informed consent and comply with study procedures

Exclusion Criteria:

1. History of myocardial infarction (MI), coronary revascularization, stroke, transient ischemic attack (TIA), or peripheral arterial revascularization procedure;
2. Current prescription or clear indication for aspirin, low-molecular-weight heparin (LMWH), direct oral anticoagulants, or any other antithrombotic medication;
3. Clear contraindication to aspirin;
4. History of significant bleeding within the past year;
5. Severe illness with limited life expectancy (i.e., <5 years);
6. Any condition that, in the investigator's judgment, would make participation unsafe for the patient.