Coronary artery calcium (CAC) is considered a useful test for enhancing risk assessment in the primary prevention setting. Clinical trials are under consideration. The National Heart, Lung, and Blood Institute convened a multidisciplinary working group on August 26 to 27, 2019, in Bethesda, Maryland, to review available evidence and consider the appropriateness of conducting further research on coronary artery calcium (CAC) testing, or other coronary imaging studies, as a way of informing decisions for primary preventive treatments for cardiovascular disease. The working group concluded that additional evidence to support current guideline recommendations for use of CAC in middle-age adults is very likely to come from currently ongoing trials in that age group, and a new trial is not likely to be timely or cost effective. The current trials will not, however, address the role of CAC testing in younger adults or older adults, who are also not addressed in existing guidelines, nor will existing trials address the potential benefit of an opportunistic screening strategy made feasible by the application of artificial intelligence. Innovative trial designs for testing the value of CAC across the lifespan were strongly considered and represent important opportunities for additional research, particularly those that leverage existing trials or other real-world data streams including clinical computed tomography scans. Sex and racial/ethnic disparities in cardiovascular disease morbidity and mortality, and inclusion of diverse participants in future CAC trials, particularly those based in the United States, would enhance the potential impact of these studies.