Abstract 16653: Coronary Artery Calcium, SPRINT Eligibility and Role of Risk Prediction for Intensive Blood Pressure Therapy: The Coronary Artery Calcium Consortium

Abstract

Introduction: Coronary artery calcium (CAC) is a strong predictor of future cardiovascular events. We assessed whether CAC scoring could be used to identify hypertensive adults aged >50 years who have cardiovascular disease (CVD) mortality rates similar to those observed in the Systolic Blood Pressure Intervention Trial (SPRINT) and who therefore might benefit from intensive blood pressure therapy. In addition, we examined the ability of CAC to stratify CVD risk among hypertensive adults, including those who are eligible for SPRINT. Methods: We studied 16,167 hypertensive adults from the CAC Consortium, among whom 5,163 were SPRINT-eligible (age >50 years, Framingham Risk Score >15%, and no diabetes mellitus). In order to determine what CAC scores were associated with CVD mortality rate observed in the standard-treatment group of SPRINT (0.43%/year), this rate was first age-standardized to the population structure of the CAC Consortium (age-standardized annual CVD mortality rate = 0.35%/year). A CAC-CVD mortality plot was then generated. A y-axis line was placed at the age-standardized CVD mortality rate, and its intersection with the CAC-CVD mortality plot was interpreted as the CAC-score equivalent of SPRINT-level risk. We also compared multivariable-adjusted hazard ratios of coronary heart disease (CHD) and CVD deaths by CAC category (0, 1-100, 100-400, >400). Results: Mean age of the study population was 58.1±10.6 years. Over a mean follow-up of 11.6±3.6 years, there were 409 CVD and 207 CHD deaths. A CAC score of 220 (confidence range 165-270) was associated with the age-standardized CVD mortality rate observed in SPRINT. Additionally, increasing CAC scores were associated with increased CHD and CVD mortality in the overall study population [CHD - CAC 100-400: Hazard ratio (95% confidence interval) 1.9 (1.0-3.4), CAC>400: 4.2 (2.3-7.4); CVD - CAC 100-400: 1.9 (1.3, 2.8), CAC>400: 3.5 (2.4, 5.1)]. A similar pattern was observed in the SPRINT-eligible population. Conclusions: CAC risk stratifies adults with hypertension, including SPRINT-eligible adults. A CAC score of around 220 can identify hypertensive adults aged >50 years with CVD risk similar to SPRINT and may therefore help identify candidates for more intensive blood pressure therapy.