Cardiovascular Phenotypes in Children with CKD: The 4C Study

Hypertension and Cardiovascular Risk Among Children with Chronic Kidney Disease

PURPOSE OF REVIEW

Cardiovascular disease is the most common cause of mortality across the lifespan of children with chronic kidney disease (CKD). Hypertension is a common and important contributor, but other factors such as obesity, dyslipidemia and mineral bone disease play a role. This narrative review focusses on studies published in the past five years that have investigated hypertension and cardiovascular risk among children with CKD.

RECENT FINDINGS

Cohort studies such as Chronic Kidney Disease in Children (CKiD) and Cardiovascular Comorbidity in Children with CKD (4C) have continued to develop our understanding of blood pressure (BP) phenotypes, and of progressive changes in the structure and function of the heart and blood vessels occurring in children with CKD. Metabolic risk factors, such as dyslipidemia, may represent an under-recognized component of care. Trial data are less common than observational evidence, but support lifestyle interventions currently used, mainly the low sodium dietary approaches to stop hypertension (DASH) diet. The findings of the recently reported Hypertension Optimal Treatment in Children with Chronic Kidney Disease trial (HOT-KID) are described in relation to the use of office BP treatment targets. Cardiovascular health is critical to the long-term outcomes of children with CKD. Recognizing and treating hypertension remains a critical component to improving outcomes, along with measures to improve concurrent cardiovascular risk factors. Some cardiovascular changes may not be reversible with transplantation and further research is needed for children at all stages of CKD.

Dyslipidemia in children with chronic kidney disease-findings from the Cardiovascular Comorbidity in Children with Chronic Kidney Disease (4C) study

BACKGROUND

Dyslipidemia is an important and modifiable risk factor for CVD in children with CKD.

METHODS

In a cross-sectional study of baseline serum lipid levels in a large prospective cohort study of children with stage 3-5 (predialysis) CKD, frequencies of abnormal lipid levels and types of dyslipidemia were analyzed in the entire cohort and in subpopulations defined by fasting status or by the presence of nephrotic range proteinuria. Associated clinical and laboratory characteristics were determined by multivariable linear regression analysis.

RESULTS

A total of 681 patients aged 12.2 ± 3.3 years with a mean eGFR of 26.9 ± 11.6 ml/min/1.73 m2 were included. Kidney diagnosis was classified as CAKUT in 69%, glomerulopathy in 8.4%, and other disorders in 22.6% of patients. Nephrotic range proteinuria (defined by a urinary albumin/creatinine ratio > 1.1 g/g) was present in 26.9%. Dyslipidemia was found in 71.8%, and high triglyceride (TG) levels were the most common abnormality (54.7%). Fasting status (38.9%) had no effect on dyslipidemia status. Except for a significant increase in TG in more advanced CKD, lipid levels and frequencies of dyslipidemia were not significantly different between CKD stages. Hypertriglyceridemia was associated with younger age, lower eGFR, shorter duration of CKD, higher body mass index (BMI-SDS), lower serum albumin, and higher diastolic blood pressure.

CONCLUSIONS

Dyslipidemia involving all lipid fractions, but mainly TG, is present in the majority of patients with CKD irrespective of CKD stage or fasting status and is significantly associated with other cardiovascular risk factors.

Long-Term Kidney Outcomes in Children with Posterior Urethral Valves: A Population-Based Cohort Study

Key Points

Background

Posterior urethral valves represent the most common cause of lower urinary tract obstruction in male infants (approximately 1/4000 live births). Long-term kidney outcomes of posterior urethral valves remain uncertain. We aimed to determine the time-varying risk of major adverse kidney events (MAKE) following children with posterior urethral valves into adulthood.

Methods

A population-based retrospective cohort study of all male children (<2 years) diagnosed with posterior urethral valves between 1991 and 2021 in Ontario, Canada. Comparator cohorts were (1) male general population and (2) male children with pyeloplasty (both <2 years). The primary outcome was MAKE (death, long-term KRT [dialysis or kidney transplant], or CKD). Time to MAKE was analyzed using multivariable-adjusted Cox proportional hazards models. We censored for provincial emigration or administrative censoring (March 31, 2022).

Results

We included 727 children with posterior urethral valves, 855 pyeloplasty comparators, and 1,013,052 general population comparators. The median follow-up time was 16.6 years (Q1–3, 8.6–24.5) overall. Throughout follow-up, 32% of children with posterior urethral valves developed MAKE versus 1% of the general population and 6% of pyeloplasty comparators. Their adjusted hazard ratio for MAKE was 36.6 (95% confidence interval, 31.6 to 42.4) versus the general population. The risk of developing MAKE declined over the first 5 years after posterior urethral valves diagnosis but remained elevated for >30-year follow-up. Children with posterior urethral valves were also at higher risk of death, CKD, long-term KRT, hypertension, and AKI than the general population or pyeloplasty comparators.

Conclusions

Children with posterior urethral valves are at higher risk of adverse long-term kidney outcomes well into adulthood.

Changes in the cardiovascular risk profile in children approaching kidney replacement therapy

Background

Despite significant cardiovascular (CV) morbidity in children on dialysis and after kidney transplantation, data on the evolution of CV damage in children with chronic kidney disease (CKD) approaching kidney replacement therapy (KRT) is unknown.

Methods

The burden, progression, and predictors of CV damage before KRT onset were explored in two prospective multicenter cohorts from Europe and Canada: Cardiovascular Comorbidity in Children with CKD (4C) and Haemodiafiltration, Heart and Height (3H) studies, conducted from 2009-19 and 2013-16, respectively. CV damage and risk factors were evaluated (i) cross sectionally at KRT-start (n = 248), and (ii) longitudinally over the 2-years preceding KRT start (n = 157; 331 patient-visits). Longitudinal analyses with mixed-effects models estimated associations of modifiable CV risk factors with change in carotid intima-media thickness (cIMT) standard deviation score (SDS), pulse wave velocity (PWV-SDS), left ventricular (LV) mass and systolic dysfunction.

Findings

248 patients, age 14.3 (12.2, 16.2) years were evaluated at median 35 (28-114) days before KRT start. Elevated cIMT-SDS and PWV-SDS were present in 43% and 25%, and LV hypertrophy and systolic dysfunction in 49% and 33%. Aortic stiffness and LV hypertrophy significantly increased, especially in the year before KRT start (adjusted odds ratio, OR 0.33, P = 0.002 and OR 0.54, P = 0.01, respectively). 79% of children had >3 modifiable CV risk factors at KRT onset. Diastolic BP and BMI were strongly associated with a linear increase in all CV measures. After controlling for CV risk factors, the time to KRT onset no longer predicted the burden of CV damage.

Interpretation

This comprehensive CV evaluation shows the progressive accrual of modifiable risk factors and a high burden of CV damage in the years preceding KRT onset. CV damage in the pre-KRT period is preventable.

Funding

Supported by EU4Health Programme (101085068) and Kidney Research UK (RP39/2013).

Nutritional management of the child with chronic kidney disease and on dialysis

While it is widely accepted that the nutritional management of the infant with chronic kidney disease (CKD) is paramount to achieve normal growth and development, nutritional management is also of importance beyond 1 year of age, particularly in toddlers, to support the delayed infantile stage of growth that may extend to 2-3 years of age. Puberty is also a vulnerable period when nutritional needs are higher to support the expected growth spurt. Inadequate nutritional intake throughout childhood can result in failure to achieve full adult height potential, and there is an increased risk for abnormal neurodevelopment. Conversely, the rising prevalence of overweight and obesity among children with CKD underscores the necessity for effective nutritional strategies to mitigate the risk of metabolic syndrome that is not confined to the post-transplant population. Nutritional management is of primary importance in improving metabolic equilibrium and reducing CKD-related imbalances, particularly as the range of foods eaten by the child widens as they get older (including increased consumption of processed foods), and as CKD progresses. The aim of this review is to integrate the Pediatric Renal Nutrition Taskforce (PRNT) clinical practice recommendations (CPRs) for children (1-18 years) with CKD stages 2-5 and on dialysis (CKD2-5D). We provide a holistic approach to the overall nutritional management of the toddler, child, and young person. Collaboration between physicians and pediatric kidney dietitians is strongly advised to ensure comprehensive and tailored nutritional care for children with CKD, ultimately optimizing their growth and development.

Long-term Effects of Kidney Transplantation Compared With Dialysis on Intima-media Thickness in Children-Results From the 4C-T Study

BACKGROUND

Children requiring kidney replacement therapy experience high burden of cardiovascular (CV) disease leading to increased mortality. Intima-media thickness (IMT) indicating atherosclerosis is a validated surrogate marker for future CV events.

METHODS

We investigated the effect of different treatment modalities (dialysis, preemptive kidney transplantation (KTx), late KTx after dialysis) on IMT by multivariable linear mixed-effect modeling. Patients were enrolled in a prospective cohort study.

RESULTS

A total of 261 analyzed children had a mean follow-up of 3 y. Children after preemptive and late KTx had lower levels of IMT when compared with dialysis. Using an interaction term, a significant progression of IMT over time was seen during dialysis (β = 0.0053 mm/y, P   =  0.004). IMT before the start of therapy was the most influential determinant in all models. Low IMT was associated with maintenance steroid treatment after preemptive KTx. High IMT on dialysis was associated with higher systolic blood pressure, lower body mass index, lower serum albumin, and lower bicarbonate.

CONCLUSIONS

IMT remained rather stable in children several years after KTx. In contrast, children on dialysis had higher IMT values, which increased over time. In these children, blood pressure control, calorie and protein intake, and acid-base homeostasis seem important. Taken together, children might profit from early transplantation to limit accumulation of CV risk.

Ambulatory Blood Pressure and Number of Subclinical Target Organ Injury Markers in Youth: The SHIP AHOY Study

Background

Hypertension in adolescence is associated with subclinical target organ injury (TOI). We aimed to determine whether different blood pressure (BP) thresholds were associated with increasing number of TOI markers in healthy adolescents.

Methods

244 participants (mean age 15.5±1.8 years, 60.1% male) were studied. Participants were divided based on both systolic clinic and ambulatory BP (ABP), into low- (<75 th percentile), mid- (75 th -90 th percentile) and high-risk (>90 th percentile) groups. TOI assessments included left ventricular mass, systolic and diastolic function, and vascular stiffness. The number of TOI markers for each participant was calculated. A multivariable general linear model was constructed to evaluate the association of different participant characteristics with higher numbers of TOI markers.

Results

47.5% of participants had at least one TOI marker: 31.2% had one, 11.9% two, 3.7% three, and 0.8% four. The number of TOI markers increased according to the BP risk groups: the percentage of participants with more than one TOI in the low-, mid-, and high groups based on clinic BP was 6.7%, 19.1%, and 21.8% (p=0.02), and based on ABP was 9.6%, 15.8%, and 32.2% (p<0.001). In a multivariable regression analysis, both clinic BP percentile and ambulatory SBP index were independently associated with the number of TOI markers. When both clinic and ABP were included in the model, only the ambulatory SBP index was significantly associated with the number of markers.

Conclusion

High SBP, especially when assessed by ABPM, was associated with an increasing number of subclinical cardiovascular injury markers in adolescents.

Decline in Left Ventricular Early Systolic Function with Worsening Kidney Function in Children with Chronic Kidney Disease: Insights from the 4C and HOT-KID Studies

INTRODUCTION

Adults with childhood-onset chronic kidney disease (CKD) have an increased risk of cardiovascular disease. First-phase ejection fraction (EF1), a novel measure of early systolic function, may be a more sensitive marker of left ventricular dysfunction than other markers in children with CKD.

OBJECTIVE

To examine whether EF1 is reduced in children with CKD.

METHODS

Children from the 4C and HOT-KID studies were stratified according to estimated glomerular filtration rate (eGFR). The EF1 was calculated from the fraction of left ventricular (LV) volume ejected up to the time of peak aortic flow velocity.

RESULTS

The EF1 was measured in children ages 10.9 ± 3.7 (mean ± SD) years, 312 with CKD and 63 healthy controls. The EF1 was lower, while overall ejection fraction was similar, in those with CKD compared with controls and decreased across stages of CKD (29.3% ± 3.7%, 23.5% ± 4.5%, 19.8% ± 4.0%, 18.5% ± 5.1%, and 16.7% ± 6.6% in controls, CKD 1, 2, 3, and ≥ 4, respectively, P < .001). The relationship of EF1 to eGFR persisted after adjustment for relevant confounders (P < .001). The effect size for association of measures of LV structure or function with eGFR (SD change per unit change in eGFR) was greater for EF1 (β = 0.365, P < .001) than for other measures: LV mass index (β = -0.311), relative wall thickness (β = -0.223), E/e' (β = -0.147), and e' (β = 0.141) after adjustment for confounders in children with CKD.

CONCLUSIONS

Children with CKD exhibit a marked and progressive decline in EF1 with falling eGFR. This suggests that EF1 is a more sensitive marker of LV dysfunction when compared to other structural or functional measures and that early LV systolic function is a key feature in the pathophysiology of cardiac dysfunction in CKD.

Recommended calcium intake in adults and children with chronic kidney disease-a European consensus statement

Mineral and bone disorders (MBD) are common in patients with chronic kidney disease (CKD), contributing to significant morbidity and mortality. For several decades, the first-line approach to controlling hyperparathyroidism in CKD was by exogenous calcium loading. Since the turn of the millennium, however, a growing awareness of vascular calcification risk has led to a paradigm shift in management and a move away from calcium-based phosphate binders. As a consequence, contemporary CKD patients may be at risk of a negative calcium balance, which, in turn, may compromise bone health, contributing to renal bone disease and increased fracture risk. A calcium intake below a certain threshold may be as problematic as a high intake, worsening the MBD syndrome of CKD, but is not addressed in current clinical practice guidelines. The CKD-MBD and European Renal Nutrition working groups of the European Renal Association (ERA), together with the CKD-MBD and Dialysis working groups of the European Society for Pediatric Nephrology (ESPN), developed key evidence points and clinical practice points on calcium management in children and adults with CKD across stages of disease. These were reviewed by a Delphi panel consisting of ERA and ESPN working groups members. The main clinical practice points include a suggested total calcium intake from diet and medications of 800-1000 mg/day and not exceeding 1500 mg/day to maintain a neutral calcium balance in adults with CKD. In children with CKD, total calcium intake should be kept within the age-appropriate normal range. These statements provide information and may assist in decision-making, but in the absence of high-level evidence must be carefully considered and adapted to individual patient needs.

Gut-immune axis and cardiovascular risk in chronic kidney disease

Patients with chronic kidney disease (CKD) suffer from marked cardiovascular morbidity and mortality, so lowering the cardiovascular risk is paramount to improve quality of life and survival in CKD. Manifold mechanisms are hold accountable for the development of cardiovascular disease (CVD), and recently inflammation arose as novel risk factor significantly contributing to progression of CVD. While the gut microbiome was identified as key regulator of immunity and inflammation in several disease, CKD-related microbiome-immune interaction gains increasing importance. Here, we summarize the latest knowledge on microbiome dysbiosis in CKD, subsequent changes in bacterial and host metabolism and how this drives inflammation and CVD in CKD. Moreover, we outline potential therapeutic targets along the gut-immune-cardiovascular axis that could aid the combat of CVD development and high mortality in CKD.

Role of hypertension in progression of pediatric CKD

Hypertension is frequent in children with chronic kidney disease (CKD). Its prevalence varies according to CKD stage and cause. It is relatively uncommon in children with congenital kidney disease, while acquired kidney disease is associated with a higher prevalence of hypertension. Studies in children with CKD utilizing ambulatory blood pressure monitoring also showed a high prevalence of masked hypertension. Uncontrolled and longstanding hypertension in children is associated with progression of CKD. Aggressive treatment of high blood pressure should be an essential part of care to delay CKD progression in children.

Identifying barriers and utility of obtaining ambulatory blood pressure monitoring in a pediatric chronic kidney disease population

BACKGROUND

Hypertension is a prevalent complication of Chronic Kidney Disease (CKD) and Ambulatory Blood Pressure Monitoring (ABPM) is the gold standard for diagnosis. The aim of our study was to assess the usefulness of obtaining ABPM and to identify barriers to ABPM in this pediatric patient population.

METHOD

In this retrospective analysis of patients with CKD stage 3-5 who were seen in one academic medical center's outpatient Pediatric Nephrology clinics between 2018 and 2021, we performed logistic regression to evaluate for associations between demographic factors and odds of having an ABPM.

RESULT

Among 96 patients included in the study, 48 patients carried a diagnosis of hypertension. 31 patients had ABPM performed with usable data. In those who had ABPM done, 21 had normotension and 10 had undertreated hypertension. Our study also showed 1 had masked hypertension and 5 had white coat hypertension or effect. We did not find a statistically significant difference in those who did or did not undergo ABPM evaluation based on gender, previous diagnosis of hypertension, distance from clinic, language preference, or racial or ethnic identity.

CONCLUSION

ABPM is a useful tool in our CKD population for the diagnosis and management of hypertension. We did not identify specific barriers to ABPM in our CKD population, and there were no differences in patients who obtained ABPM when looking at specific demographic and disease characteristics. Given these findings, we recommend focusing on areas of future improvement in spheres of patient and provider education as well as better quantification using surveys to further illuminate barriers.

Stricter Blood Pressure Control Is Associated With Lower Left Ventricular Mass in Children After Kidney Transplantation: A Longitudinal Analysis of the 4C-T Study

BACKGROUND

We assessed the effect of blood pressure (BP) control on left ventricular mass index (LVMI) and left ventricular hypertrophy (LVH).

METHODS

Ninety-six patients (64 males) ≥9 months post-kidney transplantation from the 4C-T (Cardiovascular Comorbidity in Children with Chronic Kidney Disease and Transplantation) study were analyzed longitudinally (mean follow-up, 2.6±1.3 years). Cumulative systolic blood pressure (SBP)/diastolic BP exposure was calculated as a time-averaged area under the curve and categorized: ≤50th, 50th to ≤75th, 75th to ≤90th, and >90th percentile (pct). We performed adjusted linear and logistic mixed models for LVMI and LVH, respectively.

RESULTS

At baseline, LVMI was 49.7±12.7g/m2.16 with 64% (n=61) kidney transplantation recipients displaying LVH. Compared with patients with cumulative SBP exposure >90th pct, patients with cumulative SBP of 50th to ≤75th showed a significant LVMI reduction of -5.24g/m2.16 (P=0.007). A similar tendency was seen for cumulative SBP≤50th (β=-3.70 g/m2.16; P=0.067), but patients with cumulative SBP of 75th to ≤90th pct showed no reduction. A post hoc analysis in patients with cumulative SBP≤75th revealed that median SBP exposure was at 57.5th pct. For cumulative diastolic BP, a significant LVMI reduction was seen in all 3 categories ≤90th pct compared with patients >90th pct. Patients with cumulative SBP of ≤50th or 50th to ≤75th pct showed 79% or 83% lower odds of developing LVH, respectively. Patients with cumulative diastolic BP ≤50th showed a tendency of 82% lower odds for LVH (95% CI, 0.03-1.07).

CONCLUSIONS

Stricter BP control led to regression of LVMI and LVH. Our data suggest a BP target below the 60th pct, which needs to be substantiated in a randomized controlled trial.

The significance of central blood pressure for cardiovascular target organ damage in children and adolescents after kidney transplantation

BACKGROUND

Cardiovascular (CV) complications are important causes of morbidity and mortality in children after kidney transplantation (KTx). In adults, central blood pressure (cBP) is an accepted predictor of CV sequelae. We aimed to assess the prognostic value of cBP over peripheral blood pressure (pBP) for existing CV damage.

METHODS

We measured cBP and pBP in 48 pediatric KTx recipients (mean age: 13.5 ± 4.2 years). Assessment of left ventricular mass index (LVMI) and aortic pulse wave velocity (PWV) allowed detection of CV target organ damage. LVMI and PWV were used as endpoints in multivariable linear regression models, in which cBP and pBP were compared for their predictive value.

RESULTS

Using cBP z-scores, we identified a larger number of patients with uncontrolled or untreated hypertension compared to pBP (36% vs. 7%). Central systolic blood pressure (cSBP) was a significant independent predictor of LVMI, while peripheral systolic blood pressure (pSBP) was not. Comparing central (cDBP) and peripheral (pDBP) diastolic blood pressure for their predictive value on PWV revealed a greater estimate for cDBP (0.035 vs. 0.026 for pDBP) along with a slightly better model fit for cDBP.

CONCLUSIONS

Our data in a small group of patients provide first evidence that cBP measurements in pediatric KTx recipients might be helpful in identifying patients at risk for the development of CV sequelae. Investigating a larger patient number, ideally repeatedly, is needed to create further evidence supporting our findings. In light of available devices measuring cBP noninvasively, the implementation of such clinical studies post-KTx care should be feasible. A higher resolution version of the Graphical abstract is available as Supplementary information.

Short-term safety and efficacy of escalating doses of atorvastatin for dyslipidemia in children with predialysis chronic kidney disease stage 2-5

BACKGROUND

Dyslipidemia is a potentially modifiable risk factor in patients with chronic kidney disease (CKD). Information on the safety and efficacy of statins in pediatric CKD is limited.

METHODS

Patients with CKD stage 2-5 and aged 5-18 years with low-density lipoprotein cholesterol (LDL-C) > 130 mg/dL and/or non-high-density lipoprotein cholesterol (non-HDL-C) > 145 mg/dL were enrolled from September 2019 to February 2021. All patients were administered atorvastatin 10 mg/day, which was escalated to 20 mg/day if LDL-C remained > 100 mg/dL and/or non-HDL-C > 120 mg/dL at 12 weeks. Proportion of patients achieving target lipid levels (LDL-C ≤ 100 mg/dL and non-HDL-C ≤ 120 mg/dL) and adverse events were assessed at 24 weeks.

RESULTS

Of 31 patients enrolled, target lipid levels were achieved in 45.2% (95% CI 27.8-63.7%) at 24 weeks; 22 patients required dose escalation to 20 mg at 12 weeks. There was no difference in median lipid level reduction with 10 (n = 9) versus 20 mg/day (n = 22, P = 0.3). Higher baseline LDL-C (OR 1.06, 95% CI 1.00-1.11) and older age (OR 36.5, 95% CI 2.57-519.14) were independent predictors of failure to achieve target lipid levels with 10 mg/day atorvastatin. None had persistent rise in AST/ALT > 3 times upper normal limit (UNL) or CPK > 10 times UNL. No differences were noted in adverse events due to atorvastatin 10 or 20 mg/day.

CONCLUSION

Atorvastatin (10-20 mg/day) administered for 24 weeks was safe and effectively reduced LDL-C and non-HDL-C in children with CKD stages 2-5. Patients with higher baseline LDL-C required higher doses to achieve the target. A higher resolution version of the Graphical abstract is available as Supplementary information.

Associations of Biomarkers of Kidney Tubule Health, Injury, and Inflammation with Left Ventricular Hypertrophy in Children with CKD

Key Points

Higher plasma and urine kidney injury molecule-1, urine monocyte chemoattractant protein-1, and lower urine alpha-1-microglobulin were associated with left ventricular hypertrophy, even after adjustment for confounders. Biomarkers of tubular injury, dysfunction, and inflammation may indicate the severity of kidney pathology and are associated with left ventricular hypertrophy.

Background

Left ventricular hypertrophy (LVH) is common in children with CKD and is associated with an increased risk of cardiovascular disease and mortality. We have shown that several plasma and urine biomarkers are associated with increased risk of CKD progression. As CKD is associated with LVH, we sought to investigate the association between the biomarkers and LVH.

Methods

In the CKD in Children Cohort Study, children aged 6 months to 16 years with an eGFR of 30–90 ml/min per 1.73 m2 were enrolled at 54 centers in the United States and Canada. We measured plasma biomarkers kidney injury molecule-1 (KIM-1), tumor necrosis factor receptor-1, tumor necrosis factor receptor-2, soluble urokinase-type plasminogen activator receptor and urine KIM-1, monocyte chemoattractant protein-1 (MCP-1), YKL-40, alpha-1-microglobulin (alpha-1m), and epidermal growth factor in stored plasma and urine collected 5 months after enrollment. Echocardiograms were performed 1 year after enrollment. We assessed the cross-sectional association between the log2 biomarker levels and LVH (left ventricular mass index greater than or equal to the 95th percentile) using a Poisson regression model, adjusted for age, sex, race, body mass index, hypertension, glomerular diagnosis, urine protein-to-creatinine ratio, and eGFR at study entry.

Results

Among the 504 children, LVH prevalence was 12% (n =59) 1 year after enrollment. In a multivariable-adjusted model, higher plasma and urine KIM-1 and urine MCP-1 concentrations were associated with a higher prevalence of LVH (plasma KIM-1 prevalence ratio [PR] per log2: 1.27, 95% confidence interval [CI], 1.02 to 1.58; urine KIM-1 PR: 1.21, 95% CI, 1.11 to 1.48; and urine MCP-1 PR: 1.18, 95% CI, 1.04 to 1.34). After multivariable adjustment for covariates, lower urine alpha-1m was also associated with a higher prevalence of LVH (PR: 0.90, 95% CI, 0.82 to 0.99).

Conclusions

Higher plasma and urine KIM-1, urine MCP-1, and lower urine alpha-1m were each associated with LVH prevalence in children with CKD. These biomarkers may better inform risk and help elucidate the pathophysiology of LVH in pediatric CKD.

Cardiovascular health and potential cardiovascular risk factors in young athletes

Introduction

Cardiovascular disease remains the most common cause of death worldwide, and early manifestations are increasingly identified in childhood and adolescence. With physical inactivity being the most prevalent modifiable risk factor, the risk for cardiovascular disease is deemed low in people engaging in regular physical exercise. The aim of this study was to investigate early markers and drivers of cardiovascular disease in young athletes pursuing a career in competitive sports.

Methods

One hundred and five athletes (65 males, mean age 15.7 ± 3.7 years) were characterized by measurement of body impedance to estimate body fat, blood pressure (BP), carotid femoral pulse wave velocity (PWV) to evaluate arterial elasticity, ergometry to assess peak power output, echocardiography to calculate left ventricular mass, and blood tests.

Results

Systolic BP was elevated in 12.6% and thereby more than twice as high as expected for the normal population. Similarly, structural vascular and cardiac changes represented by elevated PWV and left ventricular mass were found in 9.5% and 10.3%. Higher PWV was independently associated with higher systolic BP (β = 0.0186, p < 0.0001), which in turn was closely correlated to hemoglobin levels (β = 0.1252, p = 0.0435). In this population, increased left ventricular mass was associated with lower resting heart rate (β = -0.5187, p = 0.0052), higher metabolic equivalent hours (β = 0.1303, p = 0.0002), sport disciplines with high dynamic component (β = 17.45, p = 0.0009), and also higher systolic BP (β = 0.4715, p = 0.0354).

Conclusion

Despite regular physical exercise and in the absence of obesity, we found an unexpected high rate of cardiovascular risk factors. The association of PWV, systolic BP, and hemoglobin suggested a possible link between training-induced raised hemoglobin levels and altered vascular properties. Our results point toward the need for thorough medical examinations in this seemingly healthy cohort of children and young adults. Long-term follow-up of individuals who started excessive physical exercise at a young age seems warranted to further explore the potential adverse effects on vascular health.

Improving Clinical Care for Children With CKD: A Report From a National Kidney Foundation Scientific Workshop

Development of clinical guidelines and recommendations to address the care of pediatric patients with chronic kidney disease (CKD) has rarely included the perspectives of providers from a variety of health care disciplines or the patients and parents themselves. Accordingly, the National Kidney Foundation hosted an in-person, one and a half-day workshop that convened a multidisciplinary group of physicians, allied health care professionals, and pediatric patients with CKD and their parents, with the goal of developing key clinical recommendations regarding best practices for the clinical management of pediatric patients living with CKD. The key clinical recommendations pertained to 5 broad topics: addressing the needs of patients and parents/caregivers; modifying the progression of CKD; clinical management of CKD-mineral and bone disorder and growth retardation; clinical management of anemia, cardiovascular disease, and hypertension; and transition and transfer of pediatric patients to adult nephrology care. This report describes the recommendations generated by the participants who attended the workshop.

Associations of body mass index (BMI) and BMI change with progression of chronic kidney disease in children

BACKGROUND

Obesity is prevalent among children with chronic kidney disease (CKD) and is associated with cardiovascular disease and reduced quality of life. Its relationship with pediatric CKD progression has not been described.

METHODS

We evaluated relationships between both body mass index (BMI) category (normal, overweight, obese) and BMI z-score (BMIz) change on CKD progression among participants of the Chronic Kidney Disease in Children study. Kaplan-Meier survival curves and multivariable parametric failure time models depict the association of baseline BMI category on time to kidney replacement therapy (KRT). Additionally, the annualized percentage change in estimated glomerular filtration rate (eGFR) was modeled against concurrent change in BMIz using multivariable linear regression with generalized estimating equations which allowed for quantification of the effect of BMIz change on annualized eGFR change.

RESULTS

Participants had median age of 10.9 years [IQR: 6.5, 14.6], median eGFR of 50 ml/1.73 m2 [IQR: 37, 64] and 63% were male. 160 (27%) of 600 children with non-glomerular and 77 (31%) of 247 children with glomerular CKD progressed to KRT over a median of 5 years [IQR: 2, 8]. Times to KRT were not significantly associated with baseline BMI category. Children with non-glomerular CKD who were obese experienced significant improvement in eGFR (+ 0.62%; 95% CI: + 0.17%, + 1.08%) for every 0.1 standard deviation concurrent decrease in BMI. In participants with glomerular CKD who were obese, BMIz change was not significantly associated with annualized eGFR change.

CONCLUSION

Obesity may represent a target of intervention to improve kidney function in children with non-glomerular CKD. A higher resolution version of the Graphical abstract is available as Supplementary information.

Longitudinal follow-up on vascular morphology and function in children with kidney transplants

AIM

Our aim was to evaluate cardiovascular risk profile in 42 children with kidney transplants (KT) at the Queen Silvia Children's Hospital, Gothenburg Sweden.

METHODS

Forty-two children (7.1-18 years) with KT, time from transplantation 3.5 (0.9-13) years, were examined at inclusion and annually for three consecutive years. Eighteen matched controls were examined once. Cardiovascular phenotyping included ultra-high-frequency ultrasound (UHFUS), pulse wave velocity (PWV), and endothelial function.

RESULTS

Children with KT had higher body mass index (BMI) z-score and blood pressure (BP) z-score than healthy controls (BMI z-score: 0.4 ± 1.0 and - 0.2 ± 0.9, respectively, p = 0.02; SBP z-score: 0.5 ± 0.9 and - 0.8 ± 0.7; DBP z-score: 0.7 ± 0.7 and - 0.3 ± 0.5, respectively, p < 0.001). BP z-score decreased significantly over 3 years; other vascular markers remained unchanged. PWV and carotid intima thickness (IT) were higher in children with KT compared to healthy controls. Children with pre-emptive KT had lower radial IT and dorsal pedal media thickness (MT) compared to children with preceding dialysis.

CONCLUSION

Children with KT show increased cardiovascular risk parameters, not increasing over time. Children on dialysis before KT have more pronounced vascular changes than those with pre-emptive KT, suggesting pre-emptive transplantation more beneficial for cardiovascular health.

Arterial stiffness and blood pressure increase in pediatric kidney transplant recipients

BACKGROUND

Pulse wave velocity (PWV) is a measure of arterial stiffness. We investigated PWV and blood pressure (BP) to determine to what extent BP changes contribute to arterial stiffness, and secondly, to identify influencing factors on BP in children after kidney transplantation.

METHODS

Seventy children ≥ 2.5 years post-transplantation with at least two PWV measurements were included. Changes of systolic (Δ SBP) and diastolic BP (Δ DBP) were classified into "stable/decreasing," "1-10 mmHg increase," and " > 10 mmHg increase." Linear mixed modeling for PWV z-score (PWVz) adjusted either for Δ SBP or Δ DBP was performed. An extended dataset with monthly entries of BP, immunosuppression, and creatinine was obtained in 35 participants over a median of 74 months to perform linear mixed modeling for SBP and DBP.

RESULTS

PWVz increased with a rate of 0.11/year (95% CI 0.054 to 0.16). Compared to participants with stable BP, those with 1-10-mmHg SBP and DBP increase showed a higher PWVz of 0.59 (95% CI 0.046 to 1.13) and 0.86 (95% CI 0.43 to 1.30), respectively. A > 10-mmHg BP increase was associated with an even higher PWVz (SBP β = 0.78, 95% CI 0.22 to 1.34; DBP β = 1.37, 95% CI 0.80 to 1.94). Female sex and participants with lower eGFR showed higher PWVz. In the extended analysis, DBP was positively associated with cyclosporin A and everolimus trough levels.

CONCLUSIONS

A higher increase of PWV is seen in patients with greater BP increase, with higher cyclosporin A and everolimus trough levels associated with higher BP. This emphasizes the role of BP as a modifiable risk factor for the improvement of cardiovascular outcome after transplantation. A higher resolution version of the Graphical abstract is available as Supplementary information.

Nutritional management of the infant with chronic kidney disease stages 2-5 and on dialysis

The nutritional management of children with chronic kidney disease (CKD) is of prime importance in meeting the challenge of maintaining normal growth and development in this population. The objective of this review is to integrate the Pediatric Renal Nutrition Taskforce clinical practice recommendations for children with CKD stages 2-5 and on dialysis, as they relate to the infant from full term birth up to 1 year of age, for healthcare professionals, including dietitians, physicians, and nurses. It addresses nutritional assessment, energy and protein requirements, delivery of the nutritional prescription, and necessary dietary modifications in the case of abnormal serum levels of calcium, phosphate, and potassium. We focus on the particular nutritional needs of infants with CKD for whom dietary recommendations for energy and protein, based on body weight, are higher compared with children over 1 year of age in order to support both linear and brain growth, which are normally maximal in the first 6 months of life. Attention to nutrition during infancy is important given that growth is predominantly nutrition dependent in the infantile phase and the growth of infants is acutely impaired by disruption to their nutritional intake, particularly during the first 6 months. Inadequate nutritional intake can result in the failure to achieve full adult height potential and an increased risk for abnormal neurodevelopment. We strongly suggest that physicians work closely with pediatric renal dietitians to ensure that the infant with CKD receives the best possible nutritional management to optimize their growth and development.

Correlation of Serum FGF23 and Chronic Kidney Disease-Mineral and Bone Abnormality Markers With Cardiac Structure Changes in Maintenance Hemodialysis Patients

Background

CKD-MBD is a mineral and bone metabolism syndrome caused by chronic kidney disease. FGF23 is an important factor regulating phosphorus and is the main influencer in the CKD-MBD process. In this study, we observed the correlation among serum FGF23 and calcium, phosphorus and parathyroid hormone, and the correlation between FGF23 levels and cardiac structural changes in MHD patients.

Methods

We examined serum FGF23 concentrations in 107 cases of MHD patients using the ELISA method, recorded demographic information and biochemical data, and analyzed the correlation between serum FGF23 levels and blood calcium and blood phosphorus and PTH levels. All patients were evaluated by cardiac color ultrasound, and we finally analyzed the association between the FGF23 level and cardiac structural changes.

Results

In 107 cases of MHD patients, serum FGF23 levels were linearly associated with serum calcium (r = 0.27 P < 0.01) and parathyroid hormone levels (r = 0.25, P < 0.05). FGF 23 was negatively correlated with age (r = -0.44, P < 0.01).Serum FGF23 levels were correlated with right atrial hypertrophy in HD patients (P < 0.05). No correlation was found among FGF23, left ventricular hypertrophy/enlargement, and valve calcification stenosis (P > 0.05).

Conclusion

Serum FGF23 showed a positive correlation among blood calcium levels and PTH levels in hemodialysis patients, and FGF23 levels can affect the incidence of right atrial hypertrophy in MHD patients.

Baseline characteristics of participants enrolled in the KoreaN cohort study for Outcomes in patients With Pediatric Chronic Kidney Disease (KNOW-Ped CKD)

BACKGROUND

We developed the KoreaN cohort study for Outcomes in patients With Pediatric Chronic Kidney Disease (KNOW-Ped CKD) as a subcohort of KNOW-CKD to investigate the different characteristics of pediatric CKD between countries and races.

METHODS

Children aged younger than 18 years with stage 1 ~ 5 CKD were recruited at seven major pediatric nephrology centers in Korea. Blood and urine samples, as well as demographic and clinical data, were collected. From 2011 to 2016, 458 children were enrolled, and the baseline profiles of 437 children were analyzed.

RESULTS

The median age of the cohort was 10.9 years old, and 68.0% were males. The median estimated glomerular filtration rate was 53.1 mL/min/1.73 m². The most common etiology of CKD was congenital anomalies of the kidney and urinary tract (42.6%), followed by glomerulopathies (25.6%).

CONCLUSION

We report a cross-sectional analysis of the overall baseline characteristics such as age, CKD stage, and underlying kidney disease of the KNOW-Ped CKD. The cohort will be longitudinally followed for ten years. "A higher resolution version of the Graphical abstract is available as Supplementary information."

Inflammation in Children with CKD Linked to Gut Dysbiosis and Metabolite Imbalance

BACKGROUND

CKD is characterized by a sustained proinflammatory response of the immune system, promoting hypertension and cardiovascular disease. The underlying mechanisms are incompletely understood but may be linked to gut dysbiosis. Dysbiosis has been described in adults with CKD; however, comorbidities limit CKD-specific conclusions.

METHODS

We analyzed the fecal microbiome, metabolites, and immune phenotypes in 48 children (with normal kidney function, CKD stage G3-G4, G5 treated by hemodialysis [HD], or kidney transplantation) with a mean±SD age of 10.6±3.8 years.

RESULTS

Serum TNF-α and sCD14 were stage-dependently elevated, indicating inflammation, gut barrier dysfunction, and endotoxemia. We observed compositional and functional alterations of the microbiome, including diminished production of short-chain fatty acids. Plasma metabolite analysis revealed a stage-dependent increase of tryptophan metabolites of bacterial origin. Serum from patients on HD activated the aryl hydrocarbon receptor and stimulated TNF-α production in monocytes, corresponding to a proinflammatory shift from classic to nonclassic and intermediate monocytes. Unsupervised analysis of T cells revealed a loss of mucosa-associated invariant T (MAIT) cells and regulatory T cell subtypes in patients on HD.

CONCLUSIONS

Gut barrier dysfunction and microbial metabolite imbalance apparently mediate the proinflammatory immune phenotype, thereby driving the susceptibility to cardiovascular disease. The data highlight the importance of the microbiota-immune axis in CKD, irrespective of confounding comorbidities.

Atherosclerotic Cardiovascular Risk as an Emerging Priority in Pediatrics

Over the last decades, childhood and adolescence have emerged as an important window of opportunity to prevent atherosclerotic cardiovascular disease (ASCVD) later in life. Here, we discuss the underlying advances in the field. First, atherosclerosis development starts as early as childhood. Atherogenesis initiates in the iliac arteries and abdominal aorta and subsequently develops in higher regions of the arterial tree, as has been demonstrated in nonhuman primate studies and human autopsy studies. Obesity, hypertension, hyperlipidemia, and hyperglycemia at a young age can accelerate atherogenesis. Children and adolescents with obesity have a relative risk of ∼ 2.5 for ASCVD mortality later in life, compared to peers with a normal weight. Conversely, early prevention improves long-term cardiovascular outcomes. Second, we review disease-associated factors that add to the traditional risk factors. Various pediatric disorders carry similar or even higher risks of ASCVD than obesity, including chronic inflammatory disorders, organ transplant recipients, familial hypercholesterolemia, endocrine disorders, childhood cancer survivors, chronic kidney diseases, congenital heart diseases, and premature birth, especially after fetal growth restriction. The involved disease-associated factors that fuel atherogenesis are diverse and include inflammation, vascular, and endothelial factors. The diverse and growing list of pediatric groups at risk underscores that cardiovascular risk management has solidly entered the realm of general pediatrics. In a second review in this series, we will, therefore, focus on recent advances in cardiovascular risk assessment and management and their implications for pediatric practice.

Cardiovascular Risks of Hypertension: Lessons from Children with Chronic Kidney Disease

Hypertension is the most common complication of chronic kidney disease (CKD) in children, having a strong association with subsequential cardiovascular disease (CVD). In pediatric CKD, a considerable percentage of children with hypertension are undiagnosed or undertreated. Prior research has evaluated structural and functional markers of subclinical CVD and biomarkers in adults with CKD, while ideal biomarkers in pediatrics are still insufficiently studied. The ultimate goal of this review is to summarize what is currently known about state of hypertension, cardiovascular risk factors, and potential CVD markers/biomarkers in children with pre-dialysis CKD. We discuss omics-related biomarkers and the pathophysiologic processes of endothelial dysfunction, kidney injury, oxidative stress and inflammation that are classified by specific biomarkers. Moreover, we illustrate the existing challenges and highlight the paucity of pediatric CKD research to evaluate these CVD biomarkers for future clinical pediatric practice. Thus, achieving clinical utility of CVD biomarkers for use in pediatric CKD remains a significant challenge requiring additional efforts.

Arterial Stiffness and Chronic Kidney Disease Progression in Children

BACKGROUND AND OBJECTIVES

CKD has been linked to increased arterial stiffness in adults, but data in children with CKD remain conflicting. We aimed to investigate the longitudinal dynamics and determinants of pulse wave velocity in children with CKD and its association with CKD progression.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We performed an analysis of the Cardiovascular Comorbidity in Children with Chronic Kidney Disease (4C) study, which prospectively followed children aged 6-17 years with CKD stages 3-5. Follow-up was censored at the time of KRT initiation. Two separate analyses were performed: with absolute pulse wave velocity (primary outcome) and with pulse wave velocity standardized to height (z score; restricted to participants ≤17 years) as a sensitivity analysis.

RESULTS

In total, 667 patients with a mean baseline eGFR of 27 ml/min per 1.73 m2 were included. Pulse wave velocity above the 95th percentile was observed in 124 (20%) patients at baseline. Absolute pulse wave velocity increased gradually over the median follow-up of 2.7 (interquartile range, 0.7-4.4) years, whereas pulse wave velocity z score remained relatively stable. Absolute pulse wave velocity over time associated with time; older age; higher mean arterial pressure, LDL cholesterol, and albuminuria; and lower ferritin. Pulse wave velocity z score (n=628) was associated with the same variables and additionally, with higher diastolic BP z score, lower height z score, younger age, and girls. Of 628 patients, 369 reached the composite end point of CKD progression (50% eGFR loss, eGFR <10 ml/min per 1.73 m2, or the start of KRT) during a median follow-up of 2.4 (interquartile range, 0.9-4.6) years. Pulse wave velocity z score did not associate with CKD progression by univariable or multivariable proportional hazard analysis correcting for the established predictors eGFR, proteinuria, and BP.

CONCLUSIONS

Pulse wave velocity is increased in children with CKD but does not associate with eGFR or CKD progression.

Fibroblast Growth Factor 23 Level and Cardiovascular Parameters in Children with Chronic Kidney Disease

OBJECTIVE

To find out the serum fibroblast growth factor 23 (FGF-23) levels in different grades of CKD, and the prevalence of abnormal left ventricular mass index (LVMI), carotid intima-medial thickness (cIMT), and central pulse wave velocity (cPWV) and the risk factors including FGF-23 for these abnormalities.

METHODS

Fifty-nine patients of CKD with G2 to G5, aged 2-18 y were included. The LVMI, cIMT, and cPWV were measured using standard techniques, and serum intact FGF-23 levels were estimated at enrollment.

RESULTS

Median FGF-23 levels were significantly raised in all the grades of CKD than controls (p < 0.001), and also in G4 and G5 in comparison to G2&3 and in G5D than G5. Increased LVMI in 42 (71.2%), elevated cIMT in 30 (57.7%), and cPWV in 14 (26.9%) patients were found. The FGF-23 showed significant negative correlation with eGFRcr and positive with serum iPTH, phosphate and alkaline phosphatase levels, but had no correlations with LVMI, cIMT SDS, and cPWV SDS. Only systolic BP SDS (odds ratio 1.5, 95% CI 1.008-2.231, p = 0.046) was observed as a significant predictor for increased cIMT, while no variables had any association with abnormal LVMI and cPWV.

CONCLUSIONS

Serum FGF-23 showed higher levels with increasing grades of CKD, but no significant association with cardiovascular parameters. Systolic BP SDS was found as a significant risk factor for increased cIMT in children with CKD.

Cardiovascular Burden Is High in Pediatric Lung Transplant Recipients

BACKGROUND

Cardiovascular morbidity is common in adults after lung transplantation (LTx) but has not been described for pediatric LTx recipients. Early subclinical cardiovascular damage is reflected by increases in pulse wave velocity (PWV; indicating arteriosclerosis), intima-media thickness (IMT; indicating atherosclerosis), and left ventricular mass index (LVMI; indicating left ventricular hypertrophy).

METHODS

We annually assessed 47 pediatric LTx recipients in a prospective longitudinal study (144 observations, mean 3.1 visits/patient, range of 1-4 visits, mean follow-up 2.2 y).

RESULTS

At inclusion, increased PWV and IMT were detected in 13% and 30%, respectively, and elevated LVMI was detected in 33%. Higher PWV was associated with male sex, longer time since LTx, higher diastolic blood pressure, and lower glomerular filtration rate. Male sex and lower hemoglobin levels were associated with higher IMT, and the presence of diabetes was associated with higher LVMI.

CONCLUSIONS

Pediatric LTx recipients suffer from a high and sustained burden of subclinical cardiovascular damage. In light of improving long-term outcomes, cardiovascular morbidity needs to be addressed. Our analysis identified classical and nonclassical risk factors to be associated with the measures for cardiovascular damage, which could serve as targets for intervention.

The causes and consequences of paediatric kidney disease on adult nephrology care

Adult nephrologists often look after patients who have been diagnosed with kidney disease in childhood. This does present unique challenges to the adult nephrologist, who may be unfamiliar with the underlying cause of kidney disease as well as the complications of chronic kidney disease (CKD) that may have accumulated during childhood. This review discusses common causes of childhood CKD, in particular congenital anomalies of the kidney and urinary tract (CAKUT), autosomal dominant tubulointerstitial kidney disease (ADTKD), polycystic kidney disease, hereditary stone disease, nephrotic syndrome and atypical haemolytic uraemic syndrome. The long-term consequences of childhood CKD, such as the cardiovascular consequences, cognition and education as well as bone health, nutrition and growth are also discussed.

Evaluation of pulse wave velocity and central systolic blood pressure in children and adolescents with chronic kidney disease

OBJECTIVE

Investigate pulse wave velocity and central systolic blood pressure among pediatric population with chronic kidney disease.

METHODS

In this cross-sectional study, 57 patients (61.4% male) aged 6.2 to 17.5 years old, 44 with nondialysis chronic kidney disease and 13 on chronic dialysis, were included in the analysis. The pulse wave velocity and the central systolic blood pressure were measured with an oscillometric device with an inbuilt ARC SolverⓇ algorithm and were compared with previously established percentiles.

RESULTS

The prevalence of elevated pulse wave velocity was 21.1% (95%Cl: 11.4-33.9) and elevated central systolic blood pressure was 28.1% (95%CI: 17.0-41.5). According to the generalized linear model, there was a higher risk of elevated pulse wave velocity in patients undergoing chronic dialysis treatment than nondialysis chronic kidney disease patients (adjPR=4.24, 95%CI: 1.97-9.13, p=<0.001). Hypertensive patients (stage 2) had a higher risk of elevated pulse wave velocity than normotensive ones (adjPR=2.70, 95%CI: 1.05-6.95, p=0.040), as did patients younger than 12 years than the older patients (adjPR=2.95, 95%CI: 1.05-8.40, p=0.041). Hypertensive patients had a higher risk of elevated central systolic blood pressure than normotensives (adjPR=3.29, 95%Cl: 1.36-7.94), as did patients undergoing chronic dialysis treatment when comparing to nondialysis chronic kidney disease patients (adjPR=2.08, 95%Cl: 1.07-4.02).

CONCLUSION

Younger age, dialysis, and hypertension in children are independently associated with higher pulse wave velocity. Hypertension and dialysis are independently associated with higher central systolic blood pressure.

Low-density lipoprotein and blood pressure are important risk factors for vasculopathy in children on dialysis: a single center study

INTRODUCTION

We searched for risk factors of cardiovascular assessment among children on dialysis.

METHODS

This is a cross-sectional study of cardiovascular assessment of all patients on dialysis at xxx University Children's Hospital. Pediatric patients between the ages of 6 and 21 who were on hemodialysis and peritoneal dialysis treatment were included in the study. Cardiovascular evaluation included left ventricular mass index (LVMI), pulse wave velocity (PWV), and carotid intima-media thickness (cIMT) measurements.

RESULTS

Nineteen patients were included in this study. The LDL had a correlation with the cIMT z-score, but not to PWVz-score. Binary Logistic regression analysis found that only LDL was significantly associated to increased cIMT.

CONCLUSION

This study reports an association between high LDL and high blood pressure increased cIMT on dialyzed children. Strategies to reduce LDL and blood pressure in dialysis patients may prevent vasculopathy and long-term cardiovascular complications.

High blood pressure in children and adolescents: current perspectives and strategies to improve future kidney and cardiovascular health

Hypertension is one of the most common causes of preventable death worldwide. The prevalence of pediatric hypertension has increased significantly in recent decades. The cause of this is likely multifactorial, related to increasing childhood obesity, high dietary sodium intake, sedentary lifestyles, perinatal factors, familial aggregation, socioeconomic factors, and ethnic blood pressure (BP) differences. Pediatric hypertension represents a major public health threat. Uncontrolled pediatric hypertension is associated with subclinical cardiovascular disease and adult-onset hypertension. In children with chronic kidney disease (CKD), hypertension is also a strong risk factor for progression to kidney failure. Despite these risks, current rates of pediatric BP screening, hypertension detection, treatment, and control remain suboptimal. Contributing to these shortcomings are the challenges of accurately measuring pediatric BP, limited access to validated pediatric equipment and hypertension specialists, complex interpretation of pediatric BP measurements, problematic normative BP data, and conflicting society guidelines for pediatric hypertension. To date, limited pediatric hypertension research has been conducted to help address these challenges. However, there are several promising signs in the field of pediatric hypertension. There is greater attention being drawn on the cardiovascular risks of pediatric hypertension, more emphasis on the need for childhood BP screening and management, new public health initiatives being implemented, and increasing research interest and funding. This article summarizes what is currently known about pediatric hypertension, the existing knowledge-practice gaps, and ongoing research aimed at improving future kidney and cardiovascular health.

Sex-Based Differences in Risk Factors and Complications of Chronic Kidney Disease

Globally, females are ∼30% more likely to have pre-dialysis chronic kidney disease (CKD) than males for reasons that are not fully understood. CKD is associated with numerous adverse health outcomes which makes understanding and working to eradicating sex based disparities in CKD prevalence essential. This review maps both what is known, and what is unknown, about the way sex and gender impacts (1) the epidemiology and risk factors for CKD including age, diabetes, hypertension, obesity, smoking, and cerebrovascular disease, and (2) the complications from CKD including kidney disease progression, cardiovascular disease, CKD mineral and bone disorders, anaemia, quality-of-life, cancer and mortality. This mapping can be used to guide future research.

The burden of subclinical cardiovascular disease in children and young adults with chronic kidney disease and on dialysis

Background

Cardiovascular disease (CVD) is a common cause of morbidity and mortality even in young people with chronic kidney disease (CKD). We examined structural and functional CV changes in patients ˂30 years of age with CKD Stages 4 and 5 and on dialysis.

Methods

A total of 79 children and 21 young adults underwent cardiac computed tomography for coronary artery calcification (CAC), ultrasound for carotid intima-media thickness (cIMT), carotid–femoral pulse wave velocity (cfPWV) and echocardiography. Differences in structural (CAC, cIMT z-score, left ventricular mass index) and functional (carotid distensibility z-score and cfPWV z-score) measures were examined between CKD Stages 4 and 5 and dialysis patients.

Results

Overall, the cIMT z-score was elevated [median 2.17 (interquartile range 1.14–2.86)] and 10 (10%) had CAC. A total of 16/23 (69.5%) patients with CKD Stages 4 and 5 and 68/77 (88.3%) on dialysis had at least one structural or functional CV abnormality. There was no difference in the prevalence of structural abnormalities in CKD or dialysis cohorts, but functional abnormalities were more prevalent in patients on dialysis (P < 0.05). The presence of more than one structural abnormality was associated with a 4.5-fold increased odds of more than one functional abnormality (95% confidence interval 1.3–16.6; P < 0.05). Patients with structural and functional abnormalities [cIMT z-score >2 standard deviation (SD) or distensibility <−2 SD) had less carotid dilatation (lumen:wall cross-sectional area ratio) compared with those with normal cIMT and distensibility.

Conclusions

There is a high burden of subclinical CVD in young CKD patients, with a greater prevalence of functional abnormalities in dialysis compared with CKD patients. Longitudinal studies are required to test these hypothesis-generating data and define the trajectory of CV changes in CKD.

Insights from the 4C-T Study suggest increased cardiovascular burden in girls with end stage kidney disease before and after kidney transplantation

Mortality in children with kidney failure is higher in girls than boys with cardiovascular complications representing the most common causes of death. Pulse wave velocity (PWV), a measure of vascular stiffness, predicts cardiovascular mortality in adults. Here, PWV in children with kidney failure undergoing kidney replacement therapy was investigated to determine sex differences and potential contributing factors. Two-hundred-thirty-five children (80 girls; 34%) undergoing transplantation (150 pre-emptive, 85 with prior dialysis) having at least one PWV measurement pre- and/or post-transplantation from a prospective cohort were analyzed. Longitudinal analyses (median/maximum follow-up time of 6/9 years) were performed for PWV z-scores (PWVz) using linear mixed regression models and further stratified by the categories of time: pre-kidney replacement therapy and post-transplantation. PWVz significantly increased by 0.094 per year and was significantly higher in girls (PWVz +0.295) compared to boys, independent of the underlying kidney disease. During pre-kidney replacement therapy, an average estimated GFR decline of 4ml/min/1.73m² per year was associated with a PWVz increase of 0.16 in girls only. Higher diastolic blood pressure and low density lipoprotein were independently associated with higher PWVz during pre-kidney replacement therapy in both sexes. In girls post-transplantation, an estimated GFR decline of 4ml/min/1.73m² per year pre-kidney replacement therapy and a longer time (over 12 months) to transplantation were significantly associated with higher PWVz of 0.22 and of 0.57, respectively. PWVz increased further after transplantation and was positively associated with time on dialysis and diastolic blood pressure in both sexes. Thus, our findings demonstrate that girls with advanced chronic kidney disease are more susceptible to develop vascular stiffening compared to boys, this difference persist after transplantation and might contribute to higher mortality rates seen in girls with kidney failure.

Pediatric hemodialysis access

Pediatric hemodialysis access is a demanding field. Procedures are infrequent, technically challenging, and associated with high complication and failure rates. Each procedure affects subsequent access and transplants sites. The choice is made easier and outcomes improved when access decisions are made by a multidisciplinary, pediatric, hemodialysis access team. This manuscript reviews the current literature and offers technical suggestions to improve outcomes.

Fibroblast growth factor 23-Klotho and hypertension: experimental and clinical mechanisms

Hypertension (HTN) and chronic kidney disease (CKD) are increasingly recognized in pediatric patients and represent risk factors for cardiovascular morbidity and mortality later in life. In CKD, enhanced tubular sodium reabsorption is a leading cause of HTN due to augmented extracellular fluid volume expansion. The renin-angiotensin-aldosterone system (RAAS) upregulates various tubular sodium cotransporters that are also targets of the hormone fibroblast growth factor 23 (FGF23) and its co-receptor Klotho. FGF23 inhibits the activation of 1,25-dihydroxyvitamin D that is a potent suppressor of renin biosynthesis. Here we review the complex interactions and disturbances of the FGF23-Klotho axis, vitamin D, and the RAAS relevant to blood pressure regulation and discuss the therapeutic strategies aimed at mitigating their pathophysiologic contributions to HTN.

How FGF23 shapes multiple organs in chronic kidney disease

Chronic kidney disease (CKD) is associated with distinct alterations in mineral metabolism in children and adults resulting in multiple organ dysfunctions. Children with advanced CKD often suffer from impaired bone mineralization, bone deformities and fractures, growth failure, muscle weakness, and vascular and soft tissue calcification, a complex which was recently termed CKD-mineral and bone disorder (CKD-MBD). The latter is a major contributor to the enhanced cardiovascular disease comorbidity and mortality in these patients. Elevated circulating levels of the endocrine-acting phosphaturic hormone fibroblast growth factor (FGF) 23 are the first detectable alteration of mineral metabolism and thus CKD-MBD. FGF23 is expressed and secreted from osteocytes and osteoblasts and rises, most likely due to increased phosphate load, progressively as kidney function declines in order to maintain phosphate homeostasis. Although not measured in clinical routine yet, CKD-mediated increased circulating levels of FGF23 in children are associated with pathological cardiac remodeling, vascular alterations, and increased cognitive risk. Clinical and experimental studies addressing other FGF23-mediated complications of kidney failure, such as hypertension and impaired bone mineralization, show partly conflicting results, and the causal relationships are not always entirely clear. This short review summarizes regulators of FGF23 synthesis altered in CKD and the main CKD-mediated organ dysfunctions related to high FGF23 levels.

Hemodiafiltration maintains a sustained improvement in blood pressure compared to conventional hemodialysis in children-the HDF, heart and height (3H) study

BACKGROUND

Hypertension is prevalent in children on dialysis and associated with cardiovascular disease. We studied the blood pressure (BP) trends and the evolution of BP over 1 year in children on conventional hemodialysis (HD) vs. hemodiafiltration (HDF).

METHODS

This is a post hoc analysis of the "3H - HDF-Hearts-Height" dataset, a multicenter, parallel-arm observational study. Seventy-eight children on HD and 55 on HDF who had three 24-h ambulatory BP monitoring (ABPM) measures over 1 year were included. Mean arterial pressure (MAP) was calculated and hypertension defined as 24-h MAP standard deviation score (SDS) ≥95th percentile.

RESULTS

Poor agreement between pre-dialysis systolic BP-SDS and 24-h MAP was found (mean difference - 0.6; 95% limits of agreement -4.9-3.8). At baseline, 82% on HD and 44% on HDF were hypertensive, with uncontrolled hypertension in 88% vs. 25% respectively; p < 0.001. At 12 months, children on HDF had consistently lower MAP-SDS compared to those on HD (p < 0.001). Over 1-year follow-up, the HD group had mean MAP-SDS increase of +0.98 (95%CI 0.77-1.20; p < 0.0001), whereas the HDF group had a non-significant increase of +0.15 (95%CI -0.10-0.40; p = 0.23). Significant predictors of MAP-SDS were dialysis modality (β = +0.83 [95%CI +0.51 - +1.15] HD vs. HDF, p < 0.0001) and higher inter-dialytic-weight-gain (IDWG)% (β = 0.13 [95%CI 0.06-0.19]; p = 0.0003).

CONCLUSIONS

Children on HD had a significant and sustained increase in BP over 1 year compared to a stable BP in those on HDF, despite an equivalent dialysis dose. Higher IDWG% was associated with higher 24-h MAP-SDS in both groups.

Reducing the burden of cardiovascular disease in children with chronic kidney disease: prevention vs. damage limitation

Cardiovascular disease (CVD) is a life-limiting condition in patients with chronic kidney disease (CKD) and is rapidly progressive, especially in those with stage 5 CKD and on dialysis. Cardiovascular mortality, although reducing, remains at least 30 times higher than in the general pediatric population. The American Heart Association guidelines for cardiovascular risk reduction in high-risk pediatric patients has stratified pediatric CKD patients in the "high risk" category for the development of CVD, with associated pathological and/or clinical evidence for manifest coronary disease before 30 years of age. While improving patient survival is a key priority, other patient-related outcomes, such as psychosocial development, quality of life and growth are of major importance to children and their caregivers. Once vascular damage or calcification has developed, there are no data to suggest that they can be reversed. Treatments such as intensified dialysis and transplantation may attenuate the progression of subclinical cardiovascular disease, but no treatment to date has shown that the inexorable progression of CVD in CKD can be reversed. Thus, our management must focus on early diagnosis and robust preventative strategies to give our patients the best chance of optimal cardiovascular health and survival. In this review, the pathophysiology and importance of preventing the development of CVD in CKD is discussed.

Longitudinal outcomes of body mass index in overweight and obese children with chronic kidney disease

BACKGROUND

Longitudinal changes in body mass index (BMI) among overweight and obese children with chronic kidney disease (CKD) are not well characterized. We studied longitudinal trajectories and correlates of these trajectories, as results may identify opportunities to optimize health outcomes.

METHODS

Longitudinal changes in age-sex-specific BMI z-scores over 1851 person-years of follow-up were assessed in 524 participants of the Chronic Kidney Disease in Children Study. A total of 353 participants were categorized as normal (BMI > 5th to < 85th percentile), 56 overweight (BMI ≥ 85th to 95th percentile) and 115 obese (BMI ≥ 95th percentile) based on the average of three BMI measurements during the first year of follow-up. Studied covariates included age, sex, race, CKD etiology, corticosteroid usage, household income, and maternal education.

RESULTS

In unadjusted analysis, BMI z-scores decreased over time in elevated BMI groups (overweight: mean = - 0.06 standard deviations (SD) per year, 95% CI: - 0.11, - 0.01; obese: mean = - 0.04 SD per year, 95% CI: - 0.07, - 0.01). Among obese children, only age was associated with change in BMI z-score; children < 6 years had a mean decrease of 0.19 SD during follow-up (95% CI: - 0.30, - 0.09). Socioeconomic factors were not associated with change in BMI.

CONCLUSION

Overweight and obese children with CKD demonstrated a significant annual decline in BMI, though the absolute change was modest. Among obese children, only age < 6 years was associated with significant decline in BMI. Persistence of elevated BMI in older children and adolescents with CKD underscores the need for early prevention and effective intervention.

Pathophysiology and consequences of arterial stiffness in children with chronic kidney disease

Changes in arterial structure and function are seen early in the course of chronic kidney disease (CKD) and have been causally associated with cardiovascular (CV) morbidity. Numerous potential injuries encompassing both traditional and uremia-specific CV risk factors can induce structural arterial changes and accelerate arterial stiffening. When the buffering capacity of the normally elastic arteries is reduced, damage to vulnerable microcirculatory beds can occur. Moreover, the resultant increase to cardiac afterload contributes to the development of left ventricular hypertrophy and cardiac dysfunction. Adult studies have linked arterial stiffness with increased risk of mortality, CV events, cognitive decline, and CKD progression. Pulse wave velocity (PWV) is currently the gold standard of arterial stiffness assessment but its measurement in children is challenging due to technical difficulties and physiologic aspects related to growth and poor standardization between algorithms for calculating PWV. Nevertheless, studies in pediatric CKD have reported increased arterial stiffness in children with advanced CKD, on dialysis, and after kidney transplantation. Development of arterial stiffness in children with CKD is closely related to mineral-bone disease and hypertension, but other factors may also play a significant role. The clinical relevance of accelerated arterial stiffness in childhood on cardiovascular outcomes in adult life remains unclear, and prospective studies are needed. In this review we discuss mechanisms leading to arterial stiffness in CKD and its clinical implications, along with issues surrounding the technical aspects of arterial stiffness assessment in children.

Could arterial stiffness be early reversible target organ damage test in childhood hypertension?

OBJECTIVE

The recommended treatment for hypertension (HTN) in children has been revised recently. This study aimed to present the changes in target organ damage (TOD) and arterial stiffness parameters after treatment in children with primary HTN who were managed in accordance with the 2016 European Society of Hypertension Guidelines.

METHODS

Patients with primary HTN included in this study were newly diagnosed, untreated, and were followed-up for a minimum of 6 months. HTN was confirmed by 24-h ambulatory blood pressure monitoring (ABPM). All patients underwent the following assessments: anthropometrical measurements of body mass index (BMI), carotid intima-media thickness (cIMT), left ventricular mass index (LVMI), plasma creatinine, urea, electrolytes, uric acid, fasting plasma glucose, blood lipids, urinalysis, urine culture, and first morning urine albumin tocreatinine ratio. The ABPM device performed measurements such as central blood pressure (cBP) and pulse wave velocity (PWV).

RESULTS

Thirty-two of 104 patients were enrolled. Seventeen patients were male, and 53% were obese. Compared with pretreatment, creatinine, urea, systolic BP (SBP), diastolic BP (DBP), systolic load, diastolic load, central SBP (cSBP), cSBP z score, cDBP, and PWV z score decreased, whereas LVMI and BMI z scores were unchanged.

CONCLUSION

After BP improvement, while LVMI did not regress, the cSBP, cSBP z, and PWV z score values, which are markers of arterial stiffness, regressed. This supports the corrective effect of BP control on the cardiovascular system even in a short-term follow-up. Further longitudinal studies are needed for the assessment of BP control on arterial stiffness in childhood.

Cardiovascular disease in childhood and adolescence: Lessons from children with chronic kidney disease

Children suffering from chronic kidney disease (CKD) have the apparent highest risk for the development of cardiovascular disease (CVD) at a young age. While symptoms of CVD are characteristically absent in childhood and adolescence, remodelling of the myocardium, medium and large-sized arteries and of the microcirculation is clinically significant and can be assessed with non-invasive technology. Kidney disease and its progression are the driver of CVD, mediated by an unparalleled accumulation of risk factors converging on several comorbid conditions including hypertension, anaemia, dyslipidaemia, disturbed mineral metabolism and chronic persistent inflammation. Large prospective paediatric cohorts studies have provided valuable insights into the pathogenesis and the progression of CKD-induced cardiovascular comorbidity and have characterised the cardiovascular phenotype in young patients. They have also provided the rationale for close monitoring of risk factors and have defined therapeutic targets. Recently discovered new biomarkers could help identify the individual risk for CVD. Prevention of CVD by aggressive therapy of modifiable risk factors is essential to enable long-term survival of young patients with CKD.

Bone evaluation in paediatric chronic kidney disease: clinical practice points from the European Society for Paediatric Nephrology CKD-MBD and Dialysis working groups and CKD-MBD working group of the ERA-EDTA

Mineral and bone disorder (MBD) is widely prevalent in children with chronic kidney disease (CKD) and is associated with significant morbidity. CKD may cause disturbances in bone remodelling/modelling, which are more pronounced in the growing skeleton, manifesting as short stature, bone pain and deformities, fractures, slipped epiphyses and ectopic calcifications. Although assessment of bone health is a key element in the clinical care of children with CKD, it remains a major challenge for physicians. On the one hand, bone biopsy with histomorphometry is the gold standard for assessing bone health, but it is expensive, invasive and requires expertise in the interpretation of bone histology. On the other hand, currently available non-invasive measures, including dual-energy X-ray absorptiometry and biomarkers of bone formation/resorption, are affected by growth and pubertal status and have limited sensitivity and specificity in predicting changes in bone turnover and mineralization. In the absence of high-quality evidence, there are wide variations in clinical practice in the diagnosis and management of CKD-MBD in childhood. We present clinical practice points (CPPs) on the assessment of bone disease in children with CKD Stages 2-5 and on dialysis based on the best available evidence and consensus of experts from the CKD-MBD and Dialysis working groups of the European Society for Paediatric Nephrology and the CKD-MBD working group of the European Renal Association-European Dialysis and Transplant Association. These CPPs should be carefully considered by treating physicians and adapted to individual patients' needs as appropriate. Further areas for research are suggested.

Promoting cardiovascular health post-transplant through early diagnosis and adequate management of hypertension and dyslipidemia

Despite correction of underlying solid organ failure by transplantation, pediatric transplant recipients still have increased mortality rates compared to the general pediatric population, in part due to increased cardiovascular risk. In particular, pediatric kidney and non-kidney transplant recipients with chronic kidney disease have significant cardiovascular risk that worsens with declining kidney function. Biomarkers associated with future cardiovascular risk such as casual and ambulatory hypertension, dyslipidemia, vascular stiffness and calcification, and left ventricular hypertrophy can be detected throughout the post-transplant period and in patients with stable kidney function. Among these, hypertension and dyslipidemia are two potentially modifiable cardiovascular risk factors that are highly prevalent in kidney and non-kidney pediatric transplant recipients. Standardized approaches to appropriate BP measurement and lipid monitoring are needed to detect and address these risk factors in a timely fashion. To achieve sustained improvement in cardiovascular health, clinicians should partner with patients and their caregivers to address these and other risk factors with a combined approach that integrates pharmacologic with non-pharmacologic approaches. This review outlines the scope and impact of hypertension and dyslipidemia in pediatric transplant recipients, with a particular focus on pediatric kidney transplantation given the high burden of chronic kidney disease-associated cardiovascular risk. We also review the current published guidelines for monitoring and managing abnormalities in blood pressure and lipids, highlighting the important role of therapeutic lifestyle changes in concert with antihypertensive and lipid-lowering medications.

Cardiovascular disease in children with chronic kidney disease

PURPOSE OF REVIEW

Cardiovascular disease (CVD) is a significant cause of morbidity and mortality in children with chronic kidney disease (CKD). The cause of CVD in children with CKD is multifactorial and there are new and emerging data regarding prevalence and risk factors for CVD in this population.

RECENT FINDINGS

A number of recent publications from longitudinal cohort studies of children with CKD have greatly increased our knowledge about the prevalence and risk factors for CVD including hypertension, obesity and dyslipidaemia. Masked hypertension and isolated nocturnal hypertension both correlate with surrogate markers of CVD in children. Obesity and adiposity are associated with an increased risk of CVD. Markers other than BMI such as waist to height ratio and fat-free tissue to fat tissue ratio better correlate with the presence of CVD in children. Dyslipidaemia is extremely prevalent in the paediatric CKD population, but there is a lack of consensus on treatment. More data on the relationship between bone mineral disease and CVD continue to emerge including an association between hyperparathyroidism and isolated nocturnal hypertension.

SUMMARY

Children with CKD have multiple potentially modifiable risk factors for CVD. Research focused on CVD outcomes in children is needed.

Enteral Ca-Intake May Be Low and Affects Serum-PTH-Levels in Pre-school Children With Chronic Kidney Disease

Treatment of chronic kidney disease (CKD) mineral bone disorder (MBD) is challenging in growing children due to the high amount of calcium needed for normal bone mineralization and the required dietary phosphate restriction, which often includes intake of calcium-rich products such as milk. Therefore, enteral calcium-intake (Ca-I) was calculated. Patients: We looked at pediatric CKD-Patients aged 0-6 years. Design: We used a retrospective analysis of Ca-I from dietary data collections. Ca-I below 60% or above 100% of the D-A-CH and the KDOQI reference values were considered as severe Ca deficiency or Ca overload, respectively. Results: We had 41 children, median age 1.1 (range 0-5.8) years, body weight 7.3 (2.4-19.9) kg, and length 68 (48-105) cm at the time of first dietary data collection. Renal function was classified as CKD stage III in 20, IV in 28, V in 44, and VD in 142 dietary data collections. At the first dietary data collection, 5 children were in the CKD stage III, 10 in IV, 9 in V, and 17 were on dialysis. Only one child progressed to a higher CKD stage. In total, 234 dietary data collections were analyzed, and 65 follow-up collections were available from 33 children after a time interval of 26 (1-372) days. The median caloric intake was 120 (47-217)% of D-A-CH RDI. In 149 (63.6%) of the dietary data collections, enteral Ca-I was below the target (<100% of the D-A-CH and KDOQI RDI). Severe Ca-deficiency was found in 11 (26%) and 4 (12%) of the children at the first and second dietary data collection, respectively. In total, 11 children were on Ca-containing phosphate binders. In dietary data collection 1 and 2, there were seven children. From these, 4/7 and 4/7 patients had an enteral total Ca-I above the 100% D-A-CH-limit or above the KDOQI limit, respectively. Absolute dietary Ca-I and Ca-I normalized to body weight correlated negatively with PTH (r = -0.196, p < 0.005 and r = -0.13, p < 0.05). Conclusion: Enteral Ca-I should repeatedly be monitored in CKD children because many may may otherwise be underexposed to enteral calcium and overexposed when calcium-containing phosphate binders are given. Our findings suggest a major impact of dietary calcium supply on bone health in pediatric CKD.