Aspirin in Primary Prevention: What Changed? A Critical Appraisal of Current Evidence

Aspirin has been the mainstay of both secondary and primary prevention of cardiovascular disease for half a century. In 2018, 3 trials showed a modest reduction in cardiovascular outcomes that appeared counterbalanced by the risk of clinically significant bleeding. The latest ACC/AHA primary prevention guidelines downgraded their recommendation for aspirin use in primary prevention to that of physician preference. Despite the consistent and robust evidence previously supporting the use of aspirin in cardiovascular disease prevention, little discussion has been given to mechanisms or analytic explanations for this revision of recommendations. In this review, we explore 3 possible mechanisms that may have contributed to the alteration of our perception of aspirin's role in primary prevention. These include changes in the population potentially using aspirin in primary prevention, changes in cardiovascular disease and its presentation, and changes in aspirin itself. Here we present a translational look at knowledge gaps that should be addressed to better guide contemporary aspirin use in primary prevention. In conclusion, based on these considerations, the current recommendations might be improved by recalibration of the cardiovascular risk threshold above which aspirin should be recommended for primary prevention, including the incorporation of newer risk assessment modalities such as calcium scoring. A second enhancement would be developing a bleeding risk calculator to support clinicians' assessment of risk vs benefit. The use of enteric-coated aspirin vs noncoated aspirin should also be reassessed.