From the Guidelines
A patient with coronary artery calcification (CAC) should only be considered for aspirin therapy if they have a CAC score ≥100 and are at high risk of ischemic events, as the benefits of aspirin outweigh the bleeding risks in this subgroup, as supported by the most recent guidelines 1. The decision to start aspirin therapy in patients with CAC should be individualized, taking into account their overall cardiovascular risk profile, including factors such as age, blood pressure, cholesterol levels, diabetes status, smoking history, and family history of premature cardiovascular disease. Aspirin (typically 75-100 mg daily) has been shown to reduce the risk of non-fatal myocardial infarction, non-fatal ischemic stroke, and death from vascular causes in patients with chronic coronary syndromes, as demonstrated in a recent meta-analysis 1. However, the benefits of aspirin must be weighed against the risks of bleeding, particularly in patients with increased bleeding risk. The presence of CAC indicates atherosclerosis, but aspirin's antiplatelet effects primarily prevent clot formation rather than addressing the underlying plaque buildup. For most patients with elevated CAC scores, the focus should be on aggressive risk factor modification, including statin therapy, blood pressure control, smoking cessation, and lifestyle changes (diet, exercise, weight management). Recent guidelines, such as those from the American SCCT and the NLA, recommend considering aspirin therapy for patients with CAC ≥100, as the benefits of aspirin are thought to outweigh the risks in this subgroup 1. In contrast, patients with CAC <100 or those with increased bleeding risk may not benefit from aspirin therapy, and alternative strategies should be considered. Ultimately, the decision to start aspirin therapy in patients with CAC should be made on a case-by-case basis, taking into account the individual patient's risk profile and medical history. The most recent and highest quality study on this topic, published in 2024, supports the use of aspirin in patients with CAC ≥100, as it reduces the risk of ischemic events and improves outcomes 1.
From the Research
Aspirin Therapy in Patients with Coronary Artery Calcification (CAC)
- The decision to use aspirin therapy in patients with coronary artery calcification (CAC) depends on various factors, including the patient's bleeding risk, atherosclerotic cardiovascular disease (ASCVD) risk, and CAC score 2, 3.
- Studies have shown that patients with a CAC score of 100 or higher may benefit from aspirin therapy, especially if they have a low bleeding risk and an ASCVD risk of 5% or higher 2, 4.
- However, patients with a high bleeding risk may experience net harm from aspirin therapy, regardless of their CAC score or ASCVD risk 2, 3.
- The use of CAC scoring can help identify individuals who are likely to derive net benefit from aspirin therapy, and can inform personalized decision-making in primary prevention 5, 4.
- A CAC score of zero is associated with a low long-term risk of cardiovascular disease, and may be used to de-risk individuals and inform the safe delay or avoidance of certain preventive therapies, including aspirin 5, 6.
Key Findings
- A study of 2,191 patients found that aspirin confers a net benefit in patients with a CAC score of 100 or higher, a low bleeding risk, and an ASCVD risk of 5% or higher 2.
- Another study found that a CAC score of 100 or higher identifies individuals who would experience net benefit from aspirin therapy, but only in those with a low bleeding risk and an ASCVD risk of 5% or higher 3.
- The MESA study found that CAC scoring may be superior to the pooled cohort equations in informing the allocation of aspirin in primary prevention, and that a CAC score of 100 or higher identifies subgroups in which the number needed to treat (NNT) is lower than the number needed to harm (NNH) 4.
Implications for Clinical Practice
- The use of CAC scoring can help clinicians make informed decisions about aspirin therapy in patients with coronary artery calcification, and can inform personalized risk assessment and management 2, 3, 5, 4, 6.
- Clinicians should consider a patient's CAC score, bleeding risk, and ASCVD risk when deciding whether to prescribe aspirin therapy, and should use CAC scoring to inform personalized decision-making in primary prevention 2, 3, 5, 4, 6.