Correlation between ambulatory blood pressure variability and vasodilator function in middle-aged normotensive individuals

OBJECTIVE: The aim of this study was to investigate the association between ambulatory blood pressure variability and vasodilator function in a cohort of normotensive middle-aged individuals. PARTICIPANTS AND METHODS: This was a cross-sectional study of 285 randomly selected 40-59-year-old normotensive participants who underwent 24-h ambulatory blood pressure monitoring and brachial artery ultrasound assessment. Systolic and diastolic blood pressure variability (BPV) of 24-h, daytime, and night-time were calculated using the coefficients of variation (CV) and the average real variability (ARV) index. Brachial arterial endothelium-dependent vasodilation (EDD) was assessed in response to increased flow and endothelium-independent vasodilation (EID) was assessed in response to nitroglycerin. Relationships were explored using univariate and multivariate linear regression. RESULTS: The EDD were negatively associated with the CV of 24-h systolic blood pressure (SBP), the ARV of 24-h SBP, and diastolic blood pressure (DBP) in univariate analysis. However, the CV and ARV of 24-h SBP remained associated independently with % EDD in multivariate analysis. In addition, the mean levels of 24-h SBP and DBP, the CV of 24-h SBP and DBP, the ARV of 24-h SBP and DBP, the CV of daytime SBP, and the ARV of daytime DBP were all associated with % EID. However, in a multiple linear regression model, adjusting for covariates, only the CV and ARV of 24-h SBP, and the ARV of 24-h DBP were correlated negatively but weakly with % EID. CONCLUSION: Our results indicated that a higher 24-h BPV was associated independently with decreased endothelial-dependent and endothelial-independent vasodilator functions in a middle-aged normotensive population. Although 24-h BPV was associated with vasodilator function, relationships were attenuated after adjusting for covariates.