Central Blood Pressure Stronger Predictor of Death Than Brachial BP

Blood pressure (BP) measured at the central aorta (central blood pressure, CBP) may be a better indicator of future cardiovascular events than standard BP measured at the brachial arteries (cuff BP), according to a new analysis published in the Journal of the American College of Cardiology.

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The study used a derivation cohort to generate diagnostic thresholds and a validation cohort to test these thresholds to predict mortality. The derivation cohort included 1,272 Taiwanese patients with normal BP or untreated hypertension. The validation cohort included 2,501 Taiwanese individuals with normal BP or untreated hypertension and no history of cardiovascular disease or stroke. Follow-up for cardiovascular-related mortality was conducted for 15 years and 10 years in the derivation and validation cohorts, respectively.

Results showed similar diagnostic thresholds for CBP in the two analyses. After rounding, systolic/diastolic threshold was 110/80 mmHg for optimal BP and 130/90 mmHg for hypertension. However, the risk of cardiovascular mortality increased significantly in subjects with hypertension (hazard ratio 3.08, 95% confidence interval 1.05-9.05), compared to those with optimal BP.

According to the study authors, this is the first study to derive and validate the outcome-driven diagnostic thresholds of CBP for the diagnosis of hypertension. Despite being based only on a Taiwanese population, they note that the results represent "an important step toward the application of the CBP concept to clinical risk factor profiles for cardiovascular disease." The authors suggest using a CBP of 130/90 mm Hg as cutoff limits for normality because these values were characterized by greater discriminatory power for cardiovascular mortality in the Validation Cohort, with the caveat that the study findings may not be generalizable to other ethnic groups and further studies in this regard are needed.

In an accompanying editorial, Michael A. Weber, MD, FACC, State University of New York, Downstate College of Medicine, Brooklyn, and Raymond R. Townsend, MD, Penn Hypertension Program, University of Pennsylvania, echo the caution about generalizing the results to other ethnic group. At the same time, however, they note that the study provides important contributions to the growing understanding and importance of CBP in clinical practice, "There should be some care in generalizing the findings of this research," the write. However, "the work by Chen et. al. in establishing thresholds is a vital step in a broader use of central BP in research and clinical practice." They suggest that ongoing and future clinical trials seek to test the validity of the 130/90 mm Hg CBP threshold.

Keywords: Ethnic Groups, Stroke, Follow-Up Studies, Brachial Artery, Risk Factors, Confidence Intervals, Diastole, Hypertension, Systole, United States

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