D-006 LARGE ARTERIAL STIFFNESS AND 24-HOUR BLOOD PRESSURE VARIABILITY IN UNTREATED PATIENTS

Abstract

Objective Short time blood pressure variability (BPV), such as 24-hour ambulatory BPV, was an independent predictor for adverse cardiovascular outcome. We hypothesized that arterial stiffness, as a surrogate of cardiovascular endpoints, could be influenced by BP level as well as by BPV. Methods We performed 24-hour ambulatory BP monitoring in 439 subjects (47.4% male, mean age 53 years) who were not taking antihypertensive drugs. Standard deviation (SD) of 24-hour BP, day-night weighted average SD of daytime and nighttime BP (SDdn), and reading-to-reading average real variability of BP (ARV) were calculated as 24-hour short BPV measures. Carotid-femoral pulse wave velocity (cf-PWV) was obtained by using SphygmoCor system (Australia). Brachial-ankle PWV (ba-PWV) was measured by Omron Colin VP-1000 device (Japan). Results Pearson simple correlation analyses showed that 3 measures of systolic BPV were all positively correlated with cf-PWV and ba-PWV (r = 0.18–0.37, P < 0.001). SDdn and ARV of diastolic BP were significantly correlated with cf-PWV only (P < 0.05). Multivariate regression analyses showed that after adjustment for age, sex, body mass index, 24-hour pulse rat, current smoking and corresponding 24-hour BP level, only ARV of systolic BP was significantly associated with cf-PWV (P = 0.016) and ba-PWV(P = 0.049), whereas other systolic and diastolic BPV measures were not associated with arterial stiffness indexes (P ≥ 0.11). With 1-SD elevation in ARV of systolic BP (2.4mmHg), cf-PWV and ba-PWV increased by 0.17m/s and 0.21m/s, respectively. However, ARV added only 1% to the explained variance of cf-PWV or ba-PWV while accounting for conventional risk factors including 24-hour systolic blood pressure level. Conclusions Increased 24-hour systolic BPV, if measured as ARV, was an independent risk factor for large arterial stiffness, but its contribution was small. It indicated that in clinical practice we should mainly focus on blood pressure level, but at the same time not to ignore BPV.