A Pathophysiologic Primary Prevention Review of Aspirin Administration to Prevent Cardiovascular Thrombosis

Cardiovascular disease is the leading metabolic cause of mortality in the United States. Among current therapies, low-dose aspirin has been shown to reduce cardiovascular thrombosis. However, aspirin also causes major complications (hemorrhagic stroke and gastrointestinal bleeding). The American Heart Association recommends that aspirin only be prescribed for "high-risk" individuals. No guidelines are available as to the duration of aspirin therapy.

A reasonable approach to aspirin administration is to determine the appropriateness of aspirin therapy based on the pathophysiology of coronary artery thrombosis. It suggests that the coronary artery calcium (CAC) score be used as the basis for determining "high risk." This score was shown to accurately predict future cardiovascular events. The greater the CAC score, the greater the extent of coronary artery atherosclerotic plaque and future cardiovascular risk.

A CAC score >400 places an individual at very-high 10-year risk for an atherosclerotic event. Since aggressive medical therapy initiates stabilization of unstable atherosclerotic plaques within 1 month and reversal within 2 years, this treatment significantly reduces the risk of the individual for a cardiovascular event. Thus, most individuals aged <75 years with a CAC score of >400 should receive aspirin therapy for a maximum of 2 years.

Utilization of a CAC score greatly simplifies the decision of whom to treat with aspirin and for what duration. Importantly, focusing on two factors (hemorrhage and plaque stabilization) is easily understood by both the physician and the patient.

CAC = coronary artery calcium; CVD = cardiovascular disease; LDL = low-density lipoprotein; OCT = optical coherence tomography.