24-hour blood pressure monitoring in children with chronic renal insufficiency

Abstract

Hypertension is a frequent complication in children with chronic renal insufficiency (CRI). To better assess hypertension in pediatric patients with CRI we performed 24-hour ambulatory blood pressure monitoring (ABPM) in 19 children, mean age 12.7±4.6 years. BP was measured every 20 minutes during the day and every 30 minutes at night. The median observation time was 24 hours, the mean number of reading was 54±15, and the mean percentage of successful reading was 82±16%. In addition, we evaluated the relationship between ABPM parameters and left ventricular hypertrophy (LVH), the marker of hypertensive end-organ injury. Hypertension was defined as 1) systolic BP (SBP) or diastolic BP (DBP) >95% for age, sex and height and 2) 24-hour SBP load > 35% or 24-hour DBP load > 25%. LVH was defined as left ventricular mass (LVM) index > 95% for age and sex. Nine (47%) patients were taking angiotensin converting enzyme inhibitors (ACEI). SBP or DBP >95% for age, sex and height were found in 5 (26%) patients by either casual BP or ABPM. Mean 24-hour SBP load was 36.1±28.2% and mean 24-hour DBP load was 26.8±22.8%. SBP mean 24-hour, daytime and nighttime load >35% was demonstrated in 8 (42%), 11 (58%) and 9 (47%) patients respectively. DBP mean 24-hour, daytime and nighttime load >25% was seen in 8 (42%), 9 (47%) and 6 (32%) patients respectively. Mean dipping was 7.9±7.8% for SBP and 12.3±9.4% for DBP. Nondipping pattern was found in 10 (53%) patients for SBP and in 5 (26%) patients for DBP. Three children had higher sleep SBP and DBP than awake BP. Lower SBP dipping was associated with lower glomerular filtration rate (r=0.44, p=0.05). LVH was found in 6 (32%) patients. There was no significant relationship between ABPM data and LVM but children with higher mean 24-hour SBP had a tendency to have higher LVM index (r=0.40, p=0.06). No significant difference in ABPM data and LV indexes were found between children on ACEI and without BP medications. These results confirm the high prevalence of hypertension using ABPM criteria in children with CRI. Worse CRI is associated with less of nighttime decline in blood pressure. A higher mean 24-hour SBP may be associated with increased LVM.