Blood pressure variability and left ventricular mass index in children

Clinical implications of blood pressure variability (BPV) on subclinical organ damage in children are unknown. The authors sought to explore the potential utility of two newly derived BPV indices: weighted standard deviation (wBPSD) and real average variability (ARV), as well as two standard ambulatory blood pressure indices: average 24-hour systolic blood pressure (SBP) and 24-hour SBP load, to identify children at high risk for left ventricular (LV) hypertrophy (LVH). The study group consisted of 67 consecutive children who were referred to our institution for evaluation of suspected hypertension. LV mass was estimated by M-mode echocardiography using Devereux's formula according to the Penn convention and indexed for height(2.7) . We found a statistically significant, positive correlation between 24-hour wBPSD and LV mass index (LVMI) (ρ=0.389; P=.002) and no correlation between 24-hour ARV and LVMI (P>.05). However, partial correlation analysis of 24-hour wBPSD adjusted for body mass index (BMI) and LVMI showed only a weak correlation (ρ=0.3; P=.022). By using multiple linear regression analysis in a model with LVMI as a dependent variable and 24-hour wBPSD, 24-hour ARV, and BMI as independent variables, only BMI showed statistically significant independent positive associations with LVMI (P=.028). Results of our study showed that currently used BPV indices (24-hour wBPSD and 24-hour ARV) are not clinically reliable parameters to identify children at risk for LVH. Apparent contribution of the 24-hour wBPSD parameter to LVMI is negligible and is secondary to its close correlation with BMI (ρ=0.335 P=.009).