Hemodynamic Determinants of the Short-Term Blood Pressure Variability: Differential Roles of Arterial Stiffness and Wave Reflection

BACKGROUND: A high 24-hour ambulatory diastolic (DBP) but not systolic (SBP) blood pressure variability (BPV) is significantly predictive of long-term cardiovascular mortality in untreated hypertensive subjects, independent of office or 24-hour SBP. The present study was aimed to investigate hemodynamic factors that are independently associated with systolic and diastolic BPV from the 24-hour ambulatory blood pressure monitoring (ABPM). METHODS: A cohort of 624 normotensive and 633 untreated hypertensive participants with baseline ABPM was drawn from a community-based survey. BPV was assessed by the read-to-read average real variability of the 24-hour SBP and DBP (ARVs and ARVd, respectively). Hemodynamic variables including total peripheral resistance (TPR), carotid-femoral pulse wave velocity (cf-PWV), and amplitudes of the decomposed forward (Pf) and backward (Pb) carotid pressure waves were analyzed. RESULTS: In multivariable analyses, hemodynamic variables independently associated with 24-hour SBP were 24-hour heart rate (HR), TPR, cf-PWV, Pf, and Pb (model r2 = 0.535). Hemodynamic factors independently associated with ARV were 24-hour HR, Pf, and Pb for ARVs, and 24-hour HR, cf-PWV, Pf, and Pb for ARVd (model R2 = 0.345 and 0.220, respectively). Addition of 24-hour SBP to the ARV models only slightly improved variance explained by the models (R2 = 0.383 and 0.224, respectively). Pb accounted for >50% of total variance of ARVs and ARVd, whereas cf-PWV was a minor determinant of ARVd (<5% of total variance). CONCLUSIONS: ARVd was associated with fewer hemodynamic variables than to 24-hour SBP. Among those hemodynamic variables wave reflection but not arterial stiffness had the dominant independent association with ARV.