Debates in cardiac CT: The force of data is with CAC — and it's rock solid

In 2022, the data supporting the use of the coronary artery calcium (CAC) score for further risk assessment in asymptomatic individuals uncertain about their management is rich and rock solid. The strong correlations between CAC burden, total coronary plaque, and incident coronary heart disease and atherosclerotic cardiovascular disease events have been confirmed across multiple cohorts. This information can be used to make personalized decisions involving preventive therapy allocation, informed by absolute risk and expected absolute risk reduction. A more flexible risk management if CAC ​= ​0 is now endorsed across international guidelines, from the US to Europe and Oceania, and recent studies confirming a very low prevalence of severe coronary stenosis and of high-risk plaque features among asymptomatic people with CAC ​= ​0 provide further reassurance about the “power of zero”. In contrast, evidence supporting a potential role of coronary computed tomography angiography (CCTA) for risk assessment on top of CAC is very limited in primary prevention. The same is true for the attractive but so far unproven paradigm of using CCTA to screen for subclinical plaque in the general population in lieu of traditional risk scores. The ongoing SCOT-HEART 2 will shed light on the benefits/risks of this strategy, and we encourage our esteemed contenders to include CAC testing as part of the CCTA arm of the trial to maximize clinical relevance. Moving forward, CCTA may have a role in further enhancing the allocation of add-on therapies on top of statins, an interesting area of innovation. However, for now, we pose that rather than replacing CAC with CCTA, the priority should be to improve reimbursement and access to CAC testing, so that more individuals unsure about their risk management can benefit from this information.