LAUSR

Objective: Disturbed circadian blood pressure (BP) profile is a risk factor for cardiovascular complications in adults. The study aimed to evaluate factors affecting circadian BP profile and its association with hypertension-mediated organ damage (HMOD) in pediatric patients with primary hypertension (PH). Design and method: The study included 112 children (79 boys, 33 girls, 14.7 ± 2.7 years) with untreated PH. Circadian BP profile was assessed by 24-hour ABPM. Disturbed circadian BP profile (non-dipping) was defined as a nocturnal drop in systolic or diastolic BP (SBP, DBP) < 10%. A nocturnal drop in SBP or DBP > 20% was defined as extreme dipping. Patients were evaluated for central BP, HMOD (left ventricular mass index - LVMI, aortic pulse wave velocity, augmentation index (AIx75HR), intima-media thickness, albuminuria), and clinical and biochemical parameters, including sodium-potassium balance. Results: In the study group, the mean nocturnal drop in SBP was 10.9 ± 5.9 [%] and in DBP - 16.2 ± 8.5 [%]. Non-dipping was found in 50 (44.6%) children and extreme-dipping in 29 (25.9%) patients. The nocturnal drop in SBP correlated negatively with Z-scores of body weight (r = -0.191, p = 0.043) and BMI (r = -0.242, p = 0.010) and with LVMI [g/m2.7] (r = -0.395, p = 0.006). The nocturnal drop in SBP and DBP correlated positively with urinary potassium excretion [mmol/kg/24 h] (r = 0.656, p = 0.001 and r = 0.540, p = 0.011, respectively). Patients with disturbed circadian blood pressure profile were characterized by higher LVMI (44.5 ± 12.5 vs. 36.8 ± 8.8 [g/m2.7]) and albuminuria (median: 10.8, IQR: 5.3–53.3 vs. median: 8.1, IQR: 5.5–16.4 [mg/24 h], p = 0.043) and lower urinary potassium excretion (0.6 ± 0.2 vs. 1.1 ± 0.3 [mmol/kg/24 h]). Extreme-dipping patients had a higher AIx75HR than the other patients (median: + 3.3, IQR: -6.3- + 17.7 vs. -4.6, IQR: -17.3- + 4.0 [%], p = 0.048). Conclusions: 1. Disturbed circadian BP profile is common in children with PH and should not be considered a marker of secondary hypertension. 2. Disturbed circadian BP profile may be associated with higher body weight and lower dietary potassium intake. 3. Pediatric patients with PH and disturbed BP profile are at risk for HMOD: left ventricular hypertrophy and microalbuminuria. 4. Extreme-dipping may be associated with increased arterial stiffness in children with PH.