Coronary artery calcium (CAC) was found to improve risk-based treatment choice in stage 1 hypertension, according to study results published in The American Journal of Cardiology.
The 2017 American blood pressure (BP) guidelines called for individualized treatment of hypertension based on risk assessment. In line with those recommendations, CAC and thoracic aortic calcium (TAC) have been proposed as having an impact on risk in this patient population.
In this secondary analysis of the Multi-Ethnic Study of Atherosclerosis trial, a multicenter prospective cohort study conducted between July 2000 and August 2002, the data of 1859 participants (ages, 45-84 years; mean age, 62.8±9.4 years; 46.4% women) were examined. Participants had stage 1 hypertension (systolic BP [SBP], 130-139 mm Hg or diastolic BP 80-89 mm Hg) at baseline, but no other clinical cardiovascular disease.
The study’s primary outcome was a composite of incident atherosclerotic cardiovascular disease (ASCVD) or heart failure (HF) in 3 CAC/TAC score categories (0, 1-100, or >100). Comparisons were performed in the overall cohort, 4 high-risk subgroups in which patients had a BP < 130/80 mm Hg treated with pharmacotherapy, and a low-risk subgroup ineligible for medication therapy. In addition, the 10-year number-needed-to-treat (NNT10) for achieving SBP < 130 mm Hg and preventing the primary ASCVD/HF outcome was estimated.
Across a median of 13.8 years of follow-up (at 9-12-month intervals), 300 total events occurred. The absolute event rates were 4.1 to 10.8 per 1000 person-years in the high-risk groups for those with CAC=0 and 28.4 per 1000 person-years in the low-risk group with CAC >100.
A CAC >100 vs CAC=0 (reference point) was found to be independently associated with a higher relative risk of the composite endpoint, particularly in the low-risk subgroup (hazard ratio [HR], 9.5; 95% CI, 1.8-18.7), but also in the entire cohort and the high-risk subgroups. In the entire cohort, CAC scores between 1 and 100 and >100 compared with CAC=0 had HRs of 2.5 (95% CI, 1.7-3.7) and 4.3 (95% CI, 2.7-6.8), respectively. The NNT10 were 3 to 5 times higher for CAC=0 compared with CAC >100.
The TAC scores did not significantly affect long-term results and were not considered reliable risk modifiers or useful in determining treatment allocation.
Study limitations include a small sample size, low event rates, and the inability to estimate the number-needed-to-harm.
“Going forward, CAC may be used, in addition to traditional risk factors, to further inform the initiation or intensification of treatment to a BP goal <130/80 mmHg in patients with stage 1 hypertension, particularly in those with CAC>100,” noted the authors.
Funding and Conflicts of Interest Disclosures:
Please see original article for funding information and conflict of interest declarations.
Elshazly MB, Abdellatif A, Dargham SR, et al. Role of coronary artery and thoracic aortic calcium as risk modifiers to guide antihypertensive therapy in stage 1 hypertension (from the Multi-Ethnic Study of Atherosclerosis). Am J Cardiol. March 2020. doi:10.1016/j.amjcard.2020.02.036