Derivation and Validation of Diagnostic Thresholds for Central Blood Pressure Measurements Based on Long-Term Cardiovascular Risks
What is the threshold of central blood pressure (CBP) for diagnosing hypertension?
This was an analysis of individuals from two independently and prospectively recruited and longitudinally followed Taiwanese cohorts. The derivation cohort (for generating diagnostic thresholds for CBP) included 1,272 normotensive and untreated hypertensive patients with a median follow-up of 15 years. The derived thresholds were tested in a separate validation cohort (2,501 individuals with a median follow-up of 10 years). CBP was measured with carotid tonometry in the derivation cohort; radial artery tonometry with a generalized transfer function was used for CBP measurement in the validation cohort. Mortality was the main study endpoint. Participants did not have pre-existing cardiovascular disease.
Central systolic blood pressure and central pulse pressure were significantly associated with cardiovascular mortality (hazard ratio [HR], 1.149; 95% confidence interval [CI], 1.032-1.279 and HR, 1.102; 95% CI, 1.027-1.182), total mortality (HR, 1.09; 95% CI, 1.031-1.152 and HR, 1.065; 95% CI, 1.027-1.104), and stroke mortality (HR, 1.257; 95% CI, 1.07-1.476 and HR, 1.117; 95% CI, 1.003-1.243) in the validation cohort, respectively (p < 0.01 for all). Cuff had a significant association only with total mortality (HR, 1.061; 95% CI, 1.004-1.122) and stroke mortality (HR, 1.204; 95% CI, 1.025-1.415). A CBP value of 130/90 mm Hg was associated with better discriminatory ability than other diagnostic thresholds for defining hypertension.
In a validation cohort of Taiwanese subjects, a CBP of 130/90 mm Hg is characterized by greater discriminatory power for long-term events than other diagnostic thresholds.
This is a useful contribution to define diagnostic thresholds of CBP for the diagnosis of hypertension. Such thresholds have not been investigated in longitudinal event-based studies in the past, and CBP may be relevant for predicting cardiovascular outcomes. The limitations of the study aside (including generalizability to other populations and the use of two distinct measurement devices for CBP in the two cohorts), this study is an important step in establishing the diagnostic threshold of CBP for hypertension. Future work should validate this threshold and its response to antihypertensive therapy.
Keywords: Stroke, Cardiovascular Diseases, Risk Factors, Blood Pressure, Blood Pressure Determination, Hypertension
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