Aspirin for Primary Prevention in Patients With Elevated Coronary Artery Calcium Score: A Systematic Review of Current Evidences

Abstract

The 2019 American College of Cardiology and American Heart Association guidelines regarding low-dose aspirin in the primary prevention of atherosclerotic cardiovascular disease (ASCVD) indicate an increased risk of bleeding without a net benefit. The coronary artery calcium (CAC) score could be used to guide aspirin therapy in high-risk patients without an increased risk of bleeding. With this systematic review, we aimed to analyze studies that have investigated the role of CAC in primary prevention with aspirin. A total of 4 relevant studies were identified and the primary outcomes of interest were bleeding events and major adverse cardiac events. The outcomes of interest were stratified into 3 groups based on CAC scoring: 0, 1 to 99, and ≥100. A study concluded from 2,191 patients that with a low bleeding risk, CAC ≥100, and ASCVD risk ≥5% aspirin confers a net benefit, whereas patients with a high bleeding risk would experience a net harm, irrespective of ASCVD risk or CAC. All other studies demonstrated net benefit in patients with CAC ≥100 with a clear benefit. CAC scores correspond to calcified plaque in coronary vessels and are associated with graded increase in adverse cardiovascular events. Our review has found that in the absence of a significant bleeding risk, increased ASCVD risk and CAC score corelate with increased benefit from aspirin. A study demonstrated a decrease in the odds of myocardial infarction from 3 to 0.56 in patients on aspirin. The major drawback of aspirin for primary prevention is the bleeding complication. At present, there is no widely validated tool to predict the bleeding risk with aspirin, which creates difficulties in accurately delineating risk. Barring some discrepancy between studies, evidence shows a net harm for the use of aspirin in low ASCVD risk (<5%), irrespective of CAC score.

Keywords: aspirin; bleeding; coronary artery calcium score; net benefit.