Objectives: To analyze the relationship of 24-h blood pressure variability (BPV) with vascular structure and function using the SD and the coefficient of variation (CV).
Patients and methods: A cross-sectional study was carried out in 344 hypertensive patients (aged 54.1±11.7 years, 59.6% men). BPV was estimated with the SD and CV over 24-h, both awake and sleep, by ambulatory blood pressure monitoring. Vascular structure and function were evaluated by the ambulatory arterial stiffness index (AASI), the pulse wave velocity (PWV) using SphygmoCor and the carotid intima-media thickness (IMT) as assessed by ultrasound.
Results: The systolic blood pressure (SBP) variability was greater than the diastolic blood pressure (DBP) variability using the SD and less using CV (P<0.001). SBP variability showed a positive correlation with the IMT, PWV and AASI. The CV of the DBP showed a positive correlation with the PWV and the AASI, whereas the SD of the DBP showed a negative correlation with the AASI. In the multiple regression analysis, after adjustment, the BPV measure that maintained their associations with the IMT was the CV of awake DBP and that with the PWV were the CV and the SD of 24-h and awake SBP/DBP. The AASI maintained the associations with the BPV measure in 24-h DBP, but not in SBP. The odds ratio of the SD and the CV for vascular damage varied between 1.182 and 1.276.
Conclusion: BPV in hypertensive patients, as evaluated by both SD and CV, is associated with arterial stiffness as evaluated with the PWV. The ambulatory blood pressure monitoring is more accessible at the clinic than the PWV; therefore, the assessment of BPV (24-h, awake and sleep) may be useful for assessment of arterial stiffness.
Trial registration: ClinicalTrials.gov NCT01325064.