The purpose of this study was to investigate the association of 24-hour (24-h) brahical and aortic systolic blood pressure variabilities (BPVs) with carotid intima-media thickness (CIMT) and the differences between brachial and aortic 24-h systolic BPVs in relation to CIMT.Design and method:
445 consecutive outpatients (aged 54.0 ± 13.0 years, 57.1% men) for consultation on hypertension were recruited. 24-h brachial and aortic systolic BPVs were evaluated by average real variability (ARV) and 24-h time-weighted standard deviation (wSD) using a validated 24-h ambulatory blood pressure monitor (Mobil-O-Graph NG apparatus, Germany). Bilateral CIMT was measured by ultrasound and averaged for analysis.Results:
After adjustment for 24-h mean systolic BP, CIMT was significantly correlated with brachial and aortic ARVs and wSDs (p < 0.001). In the multiple regression model, after adjustment for confounders, 1-SD increases in brachial and aortic systolic BPVs were significantly associated with 14.50 μm and 13.71 μm increases in CIMT in ARV mode, and with 15.06 μm and 16.10 μm in wSD mode. The differences between the brachial and aortic BPV did not reach statistical significance. In the multiple logistic regressions, atherosclerosis, defined as CIMT>900 μm, was significantly associated with aortic systolic ARV [Odds Ratio (OR) = 1.33; 95% confidence interval (CI): 1.02–1.74] and wSD (OR = 1.58; 95% CI: 1.16–2.15), but not with brachial systolic ARV (OR = 1.25; 95% CI: 0.95–1.64) or wSD (OR = 1.36; 95% CI: 0.99–1.88). Receiver operator characteristics (ROC) curve analysis indicated that aortic better than brachial wSD in identifying atherosclerosis (area under the curve: 0.72 versus 0.69, P = 0.046), while there was no difference between aortic and brachial ARVs.Conclusions:
Although 24-h aortic and brachial systolic BPVs were both significantly associated with CIMT, 24-h aortic systolic BPV showed its superiority over brachial BPV in identification of atherosclerosis.