Background Hypertension and cardiovascular disease are common in children undergoing dialysis. Studies suggest that hemodiafiltration (HDF) may reduce cardiovascular mortality in adults, but data for children are scarce. Methods The HDF, Heart and Height study is a nonrandomized observational study comparing outcomes on conventional hemodialysis (HD) versus postdilution online HDF in children. Primary outcome measures were annualized changes in carotid intima-media thickness (cIMT) SD score and height SD score. Results We enrolled 190 children from 28 centers; 78 on HD and 55 on HDF completed 1-year follow-up. The groups were comparable for age, dialysis vintage, access type, dialysis frequency, blood flow, and residual renal function. At 1 year, cIMT SD score increased significantly in children on HD but remained static in the HDF cohort. On propensity score analysis, HD was associated with a +0.47 higher annualized cIMT SD score compared with HDF. Height SD score increased in HDF but remained static in HD. Mean arterial pressure SD score increased with HD only. Factors associated with higher cIMT and mean arterial pressure SD-scores were HD group, higher ultrafiltration rate, and higher b2-microglobulin. The HDF cohort had lower b2-microglobulin, parathyroid hormone, and high-sensitivity C-reactive protein at 1 year; fewer headaches, dizziness, or cramps; and shorter postdialysis recovery time. Conclusions HDF is associated with a lack of progression in vascular measures versus progression with HD, as well as an increase in height not seen in the HD cohort. Patient-related outcomes improved among children on HDF correlating with improved BP control and clearances. Confirmation through randomized trials is required.

Background Central systolic and pulse pressures are stronger predictors of cardiovascular risk and hypertensive organ damage than brachial blood pressure. It is suggested that isolated systolic hypertension typically seen in adolescents is associated with normal central blood pressure and does not lead to organ damage and this phenomenon is called spurious hypertension. Methods We assessed the prevalence of spurious hypertension and analyzed utility of pulse wave analysis as determinant of hypertensive organ damage in 294 children (62 girls; 15.0 ± 2.4 years) diagnosed as primary hypertension. White coat hypertension, ambulatory prehypertension, ambulatory hypertension, and severe ambulatory hypertension were diagnosed in 127, 29, 41, and 97 patients, respectively. Results Normal central blood pressure was found in 100% in patients with white coat hypertension, 93% in pre-hypertensives, 51.2% in those with ambulatory hypertension, and 27.8% with severe ambulatory hypertension ( p = 0.0001). Children with severe ambulatory hypertension had higher central systolic and pulse pressure, pulse wave velocity, and greater prevalence of left ventricular hypertrophy than white coat and prehypertensive children ( p < 0.05). Left ventricular mass index and carotid intima-media thickness correlated with central systolic and pulse pressure ( p < 0.05 for all). Receiver operating curve area was similar for augmentation pressure (0.5836), 24-h ambulatory systolic blood pressure (0.5841), central systolic blood pressure (0.6090), and central pulse pressure (0.5611) as predictors of left ventricular hypertrophy. Conclusions These findings suggest that pulse wave analysis is complementary to ambulatory blood pressure monitoring in assessment of risk of organ damage in hypertensive adolescents.

Although the importance of office prehypertension/high normal blood pressure (BP) has been well documented, the significance of ambulatory prehypertension (AmbPreHT) has not been determined. We analyzed markers of target organ damage and hemodynamics in adolescents with AmbPreHT in comparison with hypertensive and normotensive subjects. Out of 304 white patients aged 15.0±2.5 years with office hypertension, 30 children had AmbPreHT and were compared with 66 normotensive healthy children and 92 children with true hypertension (elevated office, ambulatory, and central BP), 22 had ambulatory hypertension (AmbHT), and 70 had severe AmbHT (SevAmbHT). Stroke volume and cardiac output were greater in AmbPreHT compared with patients with normotension but did not differ between AmbPreHT, AmbHT, and SevAmbHT. Similarly, AmbPreHT, AmbHT, and SevAmbHT had similar total peripheral resistance, lower than patients with normotension ( P <0.05). Central systolic BP was higher in patients with AmbPreHT, AmbHT, and SevAmbHT compared with normotensives ( P <0.01). In all 3 groups, the carotid intima-media thickness Z scores were significantly higher than in normotensive ( P <0.001). AmbPreHT and AmbHT patients had higher left ventricular mass index and prevalence of left ventricular hypertrophy compared with normotensive but lower compared with SevAmbHT ( P <0.001). Pulse wave velocity Z scores were increased in patients with AmbPreHT, AmbHT, and SevAmbHT compared with patients with normotension ( P <0.01). Multiple regression analysis showed that body mass index Z score, central systolic BP, and uric acid levels were significant independent predictors of left ventricular mass index. In conclusion, patients with AmbPreHT presented similar cardiovascular adaptations to those observed in patients with hypertensive and may be at risk of developing cardiovascular events.

Background Currently used pediatric kidney length normative values are based on small single-center studies, do not include kidney function assessment, and focus mostly on newborns and infants. We aimed to develop ultrasound-based kidney length normative values derived from a large group of European Caucasian children with normal kidney function. Methods Out of 1,782 children aged 0–19 years, 1,758 individuals with no present or past kidney disease and normal estimated glomerular filtration rate had sonographic assessment of kidney length. The results were correlated with anthropometric parameters and estimated glomerular filtration rate. Kidney length was correlated with age, height, body surface area, and body mass index. Height-related kidney length curves and table were generated using the LMS method. Multivariate regression analysis with collinearity checks was used to evaluate kidney length predictors. Results There was no significant difference in kidney size in relation to height between boys and girls. We found significant (p < 0.001), but clinically unimportant (Cohen’s D effect size = 0.04 and 0.06) differences between prone vs. supine position (mean paired difference = 0.64 mm, 95% CI = 0.49–0.77) and left vs. right kidneys (mean paired difference = 1.03 mm, 95% CI = 0.83–1.21), respectively. For kidney length prediction, the highest coefficient correlation was observed with height (adjusted R2 = 0.87, p < 0.0001). Conclusions We present height-related LMS-percentile curves and tables of kidney length which may serve as normative values for kidney length in children from birth to 19 years of age. The most significant predictor of kidney length was statural height. Graphic Abstract

BackgroundCardiovascular disease is prevalent in children on dialysis and accounts for almost 30% of all deaths. Randomised trials in adults suggest that haemodiafiltration (HDF) with high convection volumes is associated with reduced cardiovascular mortality compared to high-flux haemodialysis (HD); however paediatric data are scarce. We designed the haemodiafiltration, heart and height (3H) study to test the hypothesis that children on HDF have an improved cardiovascular risk profile, growth and nutritional status and quality of life, compared to those on conventional HD.We performed a non-randomised parallel-arm intervention study within the International Paediatric Haemodialysis Network Registry comparing children on HDF and conventional HD to determine annualised change in cardiovascular end-points and growth. Here we present the 3H study design and baseline characteristics of the study population.Methods190 children were screened and 177 (106 on HD and 71 on HDF) recruited from 28 centres in 10 countries. There was no difference in age, underlying diagnosis, comorbidities, previous dialysis therapy, dialysis vintage, residual renal function, type of vascular access or blood flow between HD and HDF groups. High flux dialysers were used in 63% of HD patients and ultra-pure water was available in 52%. HDF patients achieved a median convection volume of 13.3 L/m2; this was associated with the blood flow rate only ((p = 0.0004, r = 0.42) and independent of access type (p = 0.38).DiscussionThis is the largest study on dialysis outcomes in children that involves deep phenotyping across a wide range of cardiovascular, anthropometric, nutritional and health-related quality of life measures, to test the hypothesis that HDF leads to improved cardiovascular and growth outcomes compared to conventional HD.Trial registrationClinicalTrials.gov: NCT02063776. The trial was prospectively registered on the 14 Feb 2014.