Role of Coronary Artery Calcium for Stratifying Cardiovascular Risk in Adults With Hypertension

Abstract

We examined the utility of coronary artery calcium (CAC) for cardiovascular risk stratification among hypertensive adults, including those fitting eligibility for SPRINT (Systolic Blood Pressure Intervention Trial). Additionally, we used CAC to identify hypertensive adults with cardiovascular disease (CVD) mortality rates equivalent to those observed in SPRINT who may, therefore, benefit from the most intensive blood pressure therapy. Our study population included 16 167 hypertensive patients from the CAC Consortium, among whom 6375 constituted a "SPRINT-like" population. We compared multivariable-adjusted hazard ratios of coronary heart disease and CVD deaths by CAC category (0, 1-99, 100-399, ≥400). Additionally, we generated a CAC-CVD mortality curve for patients aged >50 years to determine what CAC scores were associated with CVD death rates observed in SPRINT. Mean age was 58.1±10.6 years. During a mean follow-up of 11.6±3.6 years, there were 409 CVD deaths and 207 coronary heart disease deaths. Increasing CAC scores were associated with increased coronary heart disease and CVD mortality (coronary heart disease-CAC 100-399: hazard ratio [95% CI] 1.88 [1.04-3.40], CAC ≥400: 4.16 [2.34-7.39]; CVD-CAC 100-399: 1.93 [1.31-2.83], CAC ≥400: 3.51 [2.40-5.13]). A similar increased risk was observed across 10-year atherosclerotic CVD risk categories and in the SPRINT-like population. A CAC score of 220 (confidence range, 165-270) was associated with the CVD mortality rate observed in SPRINT. CAC risk stratifies adults with hypertension, including those who are SPRINT eligible. A CAC score of 220 can identify hypertensive adults with SPRINT-level CVD mortality risk and, therefore, may be reasonable for identifying candidates for aggressive blood pressure therapy.

Keywords: blood pressure; calcium; cardiovascular disease; hypertension; risk.

Figure 1:. Absolute CHD and CVD mortality rates among hypertensives in the CAC Consortium.

Absolute (A) coronary heart disease (CHD) and (B) cardiovascular disease (CVD) mortality rates per 1000 person-years by ASCVD risk groups and CAC score categories. ASCVD indicates atherosclerotic cardiovascular disease; CAC, coronary artery calcium.

Figure 2:. CAC score equivalent of SPRINT-level risk among participants age >50 years

Graph shows the annual cardiovascular disease (CVD) mortality rate as a function of coronary artery calcium (CAC) scores among hypertensive patients age >50 years. Horizontal red line represents the age-adjusted CVD death rate observed in the SPRINT trial (0.35%/year). These lines intersect at CAC=270, with lower limit of confidence (accounting for possible 15% underestimation of risk in the CAC Consortium) at CAC=165.