[Relationship between blood pressure variability and target organ damage in children with essential hypertension]

Objective: To investigate the correlation between blood pressure variability (BPV) and target organ damage in children with essential hypertension. Methods: A retrospective review identified 144 children (104 boys (72.2%) and 40 girls (27.8%), age (11.7±2.5)years) diagnosed with essential hypertension at Children's Hospital Affiliated to Capital Institute of Pediatrics from January 2013 to June 2018. Data on indicators for assessing fundus, cardiac, and renal damages obtained included 24-hour ambulatory blood pressure monitoring, BPV, fundus oculi examination, electrocardiogram, echocardiography, renal function, 24-hour urine protein quantitation, urine microalbumin, serum and urine β(2)-microglobulin. According to the existence of target organ damage, subjects were divided into target organ damage group and non-target organ damage group. Comparison between groups was analyzed using independent sample t test, chi square test and pearson correlation analysis. Results: The study included 144 children. There were 108 children (75.0%) diagnosed with phase 1 hypertension and 36 children (25.0%) diagnosed with phase 2 hypertension. Patients in target organ damage group (n=86, 59.7%) had a higher coefficient of 24 h diastolic BPV (14.5%±3.2% vs. 13.2%±2.5% t=2.558, P=0.012), a higher coefficient of daytime systolic BPV (8.2%±2.1% vs. 7.4%±2.0%, t=2.253, P=0.026) and a higher coefficient of daytime diastolic BPV (12.8%±3.4% vs.11.1%±2.4%, t=3.188, P=0.002) compared with patients in non-target organ damage group (n=58, 40.3%). The coefficients of daytime systolic BPV and daytime diastolic BPV were significantly associated with cardiac damage (r=0.190, P=0.023; r=0.366, P<0.01) and renal damage (r=0.167, P=0.046; r=0.167, P=0.045). The coefficient of daytime diastolic BPV was positively correlated with left ventricular mass index (r=0.366, P<0.01). Conclusions: There is a correlation between BPV and target organ damage in children with essential hypertension. Daytime BPV is strongly associated with cardiac and renal damage, and daytime diastolic BPV may predict early cardiac hypertrophy. As a noninvasive method, daytime BPV can provide evidence for early identification of hypertensive target organ damage.