Log in to MyACC
CAC for Allocation of Aspirin in Primary Prevention of CVD
Study Questions:
What is the value of coronary artery calcium scoring (CAC) for guiding aspirin allocation for primary prevention using 2019 aspirin meta-analysis data on atherosclerotic cardiovascular disease (ASCVD) relative risk reduction (RRR) and bleeding risk?
Methods:
The study included 6,470 participants from the MESA (Multi-Ethnic Study of Atherosclerosis. ASCVD risk was estimated using the Pooled Cohort Equations (PCEs), and three strata were defined: <5%, 5-20%, and >20%. All participants underwent CAC scoring at baseline and CAC scores were stratified as =0, 1-99, ≥100, and ≥400. A 12% RRR in CVD events was used for 5-year number needed to treat (NNT5) calculations, and a 42% RR increase in major bleeding events was used for 5-year number needed to harm (NNH5) estimations.
Results:
Only 5% of MESA participants would qualify for aspirin consideration for primary prevention according to American College of Cardiology/American Heart Association (ACC/AHA) guidelines and using >20% estimated ASCVD risk to define “higher risk.” Benefit/harm calculations were restricted to aspirin-naïve participants aged <70 years not at high risk of bleeding (n = 3,540). The overall NNT5 with aspirin to prevent one CVD event was 476 and the NNH5 was 355. The NNT5 was also greater than or similar to the NNH5 among estimated ASCVD risk strata. Conversely, CAC ≥100 and CAC ≥400 identified subgroups in which NNT5 was lower than NNH5. This was true both overall (for CAC ≥100, NNT5 = 140 vs. NNH5 = 518) as well as within ASCVD risk strata. Also, CAC = 0 identified subgroups in which the NNT was much higher than the NNH5 (overall, NNT5 = 1,190 vs. NNH5 = 567).
Conclusions:
CAC may be superior to the PCEs to inform allocation of aspirin in primary prevention. Implementation of current 2019 ACC/AHA guideline recommendations together with the use of CAC for further risk assessment may result in a more personalized, safer allocation of aspirin in primary prevention. Confirmation of these findings in experimental settings is needed.
Perspective:
In the 2019 meta-analysis utilized for the study, aspirin was associated with reductions in the primary cardiovascular composite outcome and increases in major bleeding risks in both low and high CVD risk populations and in participants with diabetes, but the risk versus benefit was marginal. Many feel it is reasonable to conclude that aspirin should be reserved for those whose ASCVD risk is 10% while on a statin. For the many people <70 years of age who have had a CAC score, the MESA risk estimator can be used to identify risk of those on statins (https://mesa-nhlbi.org/MESACHDRisk/MesaRiskScore/RiskScore.aspx). As yet, there have been no trials conducted to test the value of aspirin for primary prevention in persons on statins.
Clinical Topics: Dyslipidemia, Geriatric Cardiology, Noninvasive Imaging, Prevention, Nonstatins, Novel Agents, Statins
Keywords: Aspirin, Atherosclerosis, Cardiovascular Diseases, Diagnostic Imaging, Diabetes Mellitus, Geriatrics, Hemorrhage, Hydroxymethylglutaryl-CoA Reductase Inhibitors, Plaque, Atherosclerotic, Primary Prevention, Risk Assessment, Risk Factors
< Back to Listings
