BACKGROUND:The use of atherosclerotic cardiovascular disease (ASCVD) risk to personalize systolic blood pressure (SBP) treatment goals is a topic of increasing interest. Therefore, we studied whether coronary artery calcium (CAC) can further guide the allocation of anti-hypertensive treatment intensity. METHODS:We included 3733 participants from the Multi-Ethnic Study of Atherosclerosis (MESA) with SBP between 120 and 179 mm Hg. Within subgroups categorized by both SBP (120-139 mm Hg, 140-159 mm Hg, and 160-179 mm Hg) and estimated 10-year ASCVD risk (using the American College of Cardiology/American Heart Assocation pooled-cohort equations), we compared multivariable-adjusted hazard ratios for the composite outcome of incident ASCVD or heart failure after further stratifying by CAC (0, 1-100, or >100). We estimated 10-year number-needed-to-treat for an intensive SBP goal of 120 mm Hg by applying the treatment benefit recorded in meta-analyses to event rates within CAC strata. RESULTS:The mean age was 65 years, and 642 composite events took place over a median of 10.2 years. In persons with SBP <160 mm Hg, CAC stratified risk for events. For example, among those with an ASCVD risk of <15% and who had an SBP of either 120 to 139 mm Hg or 140 to 159 mm Hg, respectively, we found increasing hazard ratios for events with CAC 1 to 100 (1.7 [95% confidence interval, 1.0-2.6] or 2.0 [1.1-3.8]) and CAC >100 (3.0 [1.8-5.0] or 5.7 [2.9-11.0]), all relative to CAC=0. There appeared to be no statistical association between CAC and events when SBP was 160 to 179 mm Hg, irrespective of ASCVD risk level. Estimated 10-year number-needed-to-treat for a SBP goal of 120mmHg varied substantially according to CAC levels when predicted ASCVD risk <15% and SBP <160mmHg (eg, 10-year number-needed-to-treat of 99 for CAC=0 and 24 for CAC>100, when SBP 120-139mm Hg). However, few participants with ASCVD risk <5% had elevated CAC. Furthermore, 10-year number-needed-to-treat estimates were consistently low and varied less among CAC strata when SBP was 160 to 179 mm Hg or when ASCVD risk was ≥15% at any SBP level. CONCLUSIONS:Combined CAC imaging and assessment of global ASCVD risk has the potential to guide personalized SBP goals (eg, choosing a traditional goal of 140 or a more intensive goal of 120 mm Hg), particularly among adults with an estimated ASCVD risk of 5% to 15% and prehypertension or mild hypertension.