Aspirin Therapy Based on Coronary Artery Calcium Score

Introduction to Aspirin Recommendations

The American College of Cardiology recommends considering low-dose aspirin for primary prevention in patients with a Coronary Artery Calcium (CAC) score ≥100, if bleeding risk is not elevated, as this threshold identifies individuals who derive net cardiovascular benefit that exceeds bleeding risk 1, 2, 3

For patients with a CAC score of 0, the American Heart Association suggests that aspirin should not be initiated unless the ASCVD risk exceeds 20%, as bleeding risk outweighs cardiovascular benefit in this population 2, 3, 4
The Society for Cardiovascular Computed Tomography (SCCT) guidelines recommend considering aspirin for all CAC scores >100, as this threshold is associated with a net cardiovascular benefit that exceeds bleeding risk 2, 3
The National Lipid Association (NLA) guidelines suggest that aspirin 81 mg daily is reasonable for CAC scores ≥100, as this dose is associated with a reduced risk of cardiovascular events 2, 4
The Cardiac Society of Australia and New Zealand (CSANZ) guidelines recommend that patients with CAC scores 101-400 and >400 should receive preventive aspirin, as this is associated with a substantial reduction in cardiovascular risk 1, 2, 5

The European Society of Cardiology (ESC) recommends excluding high bleeding risk patients before initiating aspirin based on CAC score, as bleeding risk can outweigh cardiovascular benefit 2, 3, 6
Absolute contraindications for aspirin therapy include active GI bleeding or peptic ulcer disease, history of intracranial hemorrhage, severe thrombocytopenia, and known aspirin allergy/hypersensitivity 6, 7

The American College of Cardiology recommends a primary prevention dose of 75-100 mg daily (or 81 mg in US formulations) for patients with a CAC score ≥100, as this dose is associated with a reduced risk of cardiovascular events 1, 2, 4, 6

For patients with aspirin intolerance or hypersensitivity but CAC ≥100, the ESC recommends clopidogrel 75 mg daily as a safe and effective alternative, with a Class I, Level A recommendation 6, 7, 8

The ESC recommends adding a proton pump inhibitor for patients at increased GI bleeding risk receiving aspirin, as this can reduce the risk of GI bleeding 6, 7
The ESC also recommends reassessing bleeding risk if initiating anticoagulation or other antithrombotic agents, as this can increase the risk of bleeding 6

The 2014 American Heart Association/American Stroke Association stroke‑prevention guideline states that a history of lobar intracerebral hemorrhage suggestive of cerebral amyloid angiopathy is sufficient to tip the balance away from anticoagulation (and, by extension, aspirin) in patients with non‑valvular atrial fibrillation. 9

The 2010 ACC/AHA secondary‑prevention guideline (published in Circulation) recommends that aspirin should not be withheld when there is an unequivocal cardiovascular indication such as a recent myocardial infarction, unstable angina, or acute coronary syndrome. 10

According to a 2023 article in JACC: Cardiovascular Imaging, a coronary artery calcium (CAC) score ≥ 100, in the absence of hemorrhagic complications, can be used to identify patients in whom the cardiovascular benefits of aspirin may outweigh the bleeding risk associated with cerebral amyloid angiopathy. 11

The 2011 Stroke guideline recommends clopidogrel 75 mg daily as an alternative antiplatelet agent when aspirin is contraindicated, while emphasizing that the same hemorrhagic‑risk assessment applies. 12