Coronary Artery Calcium to Guide a Personalized Risk-Based Approach to Initiation and Intensification of Antihypertensive Therapy
Background—There is interest in using atherosclerotic cardiovascular disease (ASCVD) risk to personalize systolic blood pressure (SBP) treatment goals. Therefore, we studied whether Coronary Artery Calcium (CAC) can further guide the allocation of anti-hypertensive treatment intensity.
Methods—We included 3,733 participants from the Multi-Ethnic Study of Atherosclerosis with SBP between 120-179mmHg. Within subgroups categorized by both SBP (120-139, 140-159, 160-179mmHg) and estimated 10-year ASCVD risk (using the ACC/AHA pooled-cohort equations), we compared multivariable-adjusted hazard ratios (HRs) 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 (NNT10) for an intensive SBP goal of 120mmHg by applying the treatment benefit recorded in meta-analyses to event rates within CAC strata.
Results—Mean age was 65 years. There were 642 composite events over a median of 10.2 years. In persons with SBP <160mmHg, CAC stratified risk for events. For example, among those with ASCVD risk <15% and who had SBP of either 120-139 or 140-159mmHg, respectively, we found increasing HRs for events with CAC 1-100 (1.7 [95% CI, 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 160-179mmHg, irrespective of ASCVD risk level. Estimated NNT10 for a SBP goal of 120mmHg varied substantially according to CAC levels when predicted ASCVD risk <15% and SBP <160mmHg (e.g. NNT10 of 99 for CAC=0 and 24 for CAC>100, when SBP 120-139mmHg). However, few participants with ASCVD risk <5% had elevated CAC. Furthermore, NNT10 estimates were consistently low and varied less among CAC strata when SBP was 160-179mmHg or when ASCVD risk was ≥15% at any SBP level.
Conclusions—Combined CAC-imaging and assessment of global ASCVD risk has potential to guide personalized SBP goals (e.g., choosing a traditional goal of 140 or a more intensive goal of 120 mmHg), particularly among adults with estimated ASCVD risk 5-15% and pre-hypertension or mild hypertension.
- Received October 3, 2016.
- Accepted November 2, 2016.