Cardiovascular complications in pediatric end-stage renal disease

Long-term all-cause mortality and cardiovascular outcomes in Scottish children after initiation of renal replacement therapy: a national cohort study

BACKGROUND

Data on long-term outcomes in children who have received renal replacement therapy (RRT) for end-stage renal disease are limited.

METHODS

We studied long-term survival and incidence of fatal and nonfatal cardiovascular disease (CVD) events and determinants of these outcomes in children who initiated RRT between 1961 and 2013 using data from the Scottish Renal Registry (SRR). Linkage to morbidity records was available from 1981.

RESULTS

A total of 477 children of whom 55% were boys, almost 50% had congenital urinary tract disease (CAKUT), 10% received a transplant as the first mode of RRT and almost 60% were over 11 years of age at start of RRT were followed for a median of 17.8 years (interquartile range (IQR) 8.7-26.6 years). Survival was 87.3% (95% confidence interval (CI) 84.0-90.1) at 10 years and 77.6% (95% CI 73.3-81.7) at 20 years. During a median follow-up of 14.96 years (IQR 7.1-22.9), 20.9% of the 381 patients with morbidity data available had an incident of CVD event. Age < 2 years at start of RRT, receiving dialysis rather than a kidney transplant and primary renal disease (PRD) other than CAKUT or glomerulonephritis (GN), were associated with a higher risk of all-cause mortality. Male sex, receiving dialysis rather than a kidney transplant and PRD other than CAKUT or GN, was associated with a higher risk of CVD incidence.

CONCLUSIONS

Mortality and CVD incidence among children receiving RRT are high. PRD and RRT modality were associated with increased risk of both all-cause mortality and CVD incidence.

Cardiovascular risk factors in children after kidney transplantation--from short-term to long-term follow-up

Cardiovascular-related mortality is 100-fold higher in pediatric renal transplant recipients than in the age-matched general population. Seventy-seven post-renal transplant children's charts were reviewed for cardiovascular risk factors at two and six months after transplantation (short term) and at two yr after transplantation and the last follow-up visit (mean 7.14 ± 3.5 yr) (long term). Significant reduction was seen in cardiovascular risk factors prevalence from two months after transplantation to last follow-up respectively: Hypertension from 52.1% to 14%, hypercholesterolemia from 48.7% to 33%, hypertriglyceridemia from 50% to 12.5%, anemia from 29.6% to 18.3%, hyperparathyroidism from 32% to 18.3% and hyperglycemia from 11.7% to 10%, and left ventricular hypertrophy from 25.8% at short term to 15%. There was an increase in the prevalence of obesity from 1.5% to 3.9% and of CKD 3-5 from 4.75% to 24%. The need for antihypertensive treatment decreased from 54% to 42%, and the percentage of patients controlled by one medication rose from 26% to 34%, whereas the percentage controlled by 2, 3, and 4 medications decreased from 21.9%, 5.5%, and 1.4% to 6%, 2%, and 0. Children after renal transplantation appear to have high rates of cardiovascular risk factors, mainly on short-term follow-up.

Leptin and plasminogen activator inhibitor-1 levels in children on chronic dialysis

PURPOSE

In this study, it is aimed to compare the serum leptin and PAI-1 levels and evaluate their relationship in children on hemodialysis (HD) and peritoneal dialysis (PD).

METHOD

Thirty-six patients on HD (mean age: 15.0 ± 2.8 years), 19 patients on PD (mean age: 13.0 ± 3.5 years) and 15 healthy subjects (mean age: 14.5 ± 2.7 years) were included in the study. Laboratory investigations included blood count, biochemical parameters, serum iron, iron binding capacity, parathormone, erythrocyte sedimentation rate, C-reactive protein (CRP), prothrombin time (PT), partial thromboplastin time (PTT), fibrinogen, serum leptin and PAI-1 levels.

RESULTS

Serum leptin levels were significantly higher in HD group than in control group when the effects of BMI and sex were controlled, while PD and control groups had similar leptin levels. PAI-1 levels were also significantly higher in HD group than in control group, while there was no statistically significant difference in PAI-1 levels of PD and control group. PAI-1 levels and leptin levels were significantly correlated, which was independent of the effect of BMI in both HD and PD groups when they are evaluated separately.

CONCLUSION

Results of our study showed that HD patients had higher leptin and PAI-1 levels and leptin and PAI-1 levels were correlated significantly in both patient groups. The effect of elevated serum leptin and PAI-1 levels on the cardiovascular complications remains to be established.

The impact of change in volume and left-ventricular hypertrophy on left-ventricular mechanical dyssynchrony in children with end-stage renal disease

Left-ventricular dyssynchrony (LVD) adversely affects systolic performance and has not been previously evaluated in children with end-stage renal disease (ESRD). We hypothesized (1) that LVD in children with ESRD would be significantly increased compared with controls and (2) that volume load and left-ventricular hypertrophy (LVH) would be associated with increased LVD. This was a prospective observational study in which real-time three-dimensional echocardiographic data were acquired in 27 stable children with ESRD (13 peritoneal dialysis [PD] and 14 hemodialysis [HD]) and 29 normal controls. Data were acquired before and after an HD session. Dyssynchrony index (SDI) was defined per standard formulae and was normalized to cardiac cycle duration (SDIp). Left-ventricular mass (LVM) was obtained from M-mode echocardiography and was normalized to height(2.7) (LVM index). The mean age (13.8 vs. 11.3 years) and SDI, SDIp, LVM, and LVM index were significantly greater among children with ESRD than among controls (p < 0.05). Demographics and heart rates were comparable between HD and PD subgroups, whereas SDI 16 and 12 segments, SDIp 16 segments, and LVM were significantly greater in the HD group. SDI and SDIp 16 segments improved after an HD session (p < 0.05); LVM and LVM index remained unchanged. LVD was significantly greater in patients with LVH compared with those without LVH. Children with ESRD had significant LVD and increased LVM compared with controls. Increased LVD in those undergoing HD rather than PD, as well as the improvement in synchrony after HD, suggest that volume may modulate LVD. LVD was increased in children with LVH. LVD in children with ESRD may have pathogenic implications.

Cardiovascular risk assessment in children following kidney transplantation

CV diseases are the leading cause of death among patients with ESRD. RTX decreases the CV risk; however, it still remains definitely higher than that of the general population. Large multicenter and longitudinal studies are difficult to perform and hard end-points of CV events are usually missing among pediatric population. Thus, appropriate estimation of CV risk is of crucial importance to define the potential hazards and to evaluate the effect of treatments aimed to reduce the risk. A number of validated non-invasive methods are available to assess the extent of CV damage in adults, such as calcification scores, cIMT, aPWV, 24-h ABPM, AASI, and HRV; however, they need adaptation, standardization, and validation in pediatric studies. cIMT and PWV are the most promising methods, as pediatric normative values are already present. The up-to-date treatment of ESRD aims not only to save life, but to offer the patient a life expectancy approaching that of the healthy population and to ensure a reasonable quality of life.

Hypertension and future cardiovascular health in pediatric end-stage renal disease patients

BACKGROUND

There are now numerous studies that have documented an increased risk of cardiovascular morbidity and mortality in young adults who had childhood-onset end-stage renal disease (ESRD). Since the number of such patients surviving to adulthood is increasing, strategies to reduce this risk are urgently needed.

METHODS

The various risk factors contributing to adult cardiovascular disease in this population will be reviewed, with an emphasis on hypertension and its control. Data demonstrating the prevalence of hypertension in childhood chronic kidney disease as well as the results of improved blood pressure control in ESRD will also be presented.

CONCLUSIONS

Hypertension is exceedingly common in pediatric ESRD patients and frequently poorly controlled. Efforts to improve blood pressure control in this patient population could potentially reduce future cardiovascular morbidity and mortality.

Validating a new oscillometric device for aortic pulse wave velocity measurements in children and adolescents

BACKGROUND

Pulse wave velocity (PWV) is an indicator of aortic stiffness and a predictor of cardiovascular risk. Applanation tonometry (e.g., SphygmoCor) is a well-established method to measure aortic PWV (aPWV). The Vicorder, a new oscillometric device, has not been validated in children and adolescents.

METHODS

We performed intra- and interobserver repeatability studies in 14 individuals using the Vicorder. Vicorder and SphygmoCor measurements were compared in 156 healthy children (6-18 years) using two different path length measurements.

RESULTS

Intra- and interobserver repeatabilities of the Vicorder were excellent with coefficients of variation of 5.6% and 5.8% and intraclass correlation coefficients (ICCs) of 0.8 and 1.0. aPWV calculated using the distances (suprasternal notch-to-femoral recording point) - (suprasternal notch-to-carotid artery), the path length most commonly used in adults, revealed a mean of 4.8 ± 0.7 m/s for SphygmoCor and 4.9 ± 0.6 m/s for Vicorder. The percentage deviation between both devices was 13.0% and the limit of agreement (LoA) ranged from -1.0 to 1.7 m/s reflecting a good concordance. Using a path length that measured the distance from suprasternal notch to femoral recording point via the umbilicus (Umb), an even better agreement was found (percentage deviation: 11.8%, LoA: -1.0 to 1.6 m/s).

CONCLUSIONS

Vicorder aPWV values are similar to those obtained by SphygmoCor applanation tonometry. The best agreement between devices was obtained with the path length that most accurately describes the aortic tree. Excellent intra- and interobserver repeatability and ease of measurements make Vicorder appropriate for large multicentre studies in children and adolescents.

Longitudinal relations between obesity and hypertension following pediatric renal transplantation

Obesity and hypertension frequently complicate renal transplantation (RTxp). The objective was to assess relations among obesity, hypertension, and glucocorticoids in pediatric RTxp recipients. A retrospective cohort study was carried out in 141 RTxp recipients, 2-21 years of age, with >or=12 months of follow-up. Body mass index Z-score (BMI-Z), systolic and diastolic blood pressure Z-scores (SBP-Z and DBP-Z), and medications at 1, 3, 6, and 12 months and annually thereafter were recorded. Quasi-least squares regression analysis was used. The prevalence of obesity (BMI>or=95th percentile) increased from 13% at baseline to >30% from 3 months onward. Greater glucocorticoid exposure (mg/kg/day) was associated with greater increases in BMI-Z (p<0.001). This association was greater in males, younger recipients, and those with lower baseline BMI-Z (all interactions p<0.02). The prevalence of systolic hypertension (SBP>or=95th percentile) was 73% at 1 month and >or=40% at all follow-up visits. Greater glucocorticoid exposure (p<0.001) and increases in BMI-Z (p=0.005) were independent determinants of SBP-Z over time. Cyclosporine (versus tacrolimus) was independently associated with greater SBP-Z and DBP-Z (p=0.001). Sustained obesity and hypertension frequently complicated pediatric RTxp. Obesity was an independent determinant of systolic hypertension. Strategies are needed to prevent obesity and its impact on hypertension, cardiovascular disease, and allograft survival.

A standard, noninvasive monitoring of hematocrit algorithm improves blood pressure control in pediatric hemodialysis patients

Accurate dry weight assessment is difficult in pediatric hemodialysis patients but is essential to prevent chronic fluid overload, hypertension, and cardiovascular morbidity. A noninvasive monitoring (NIVM) of hematocrit-guided ultrafiltration algorithm was studied prospectively in 20 pediatric hemodialysis patients. The algorithm targeted the first 50% of total goal ultrafiltration to be removed during the first hour of dialysis with a maximum blood volume change of 8 to 12% per hour. The second 50% was removed during the remaining treatment time with a maximum blood volume change of 5% per hour. Data that were collected at baseline and 6 mo included weight, BP, number of antihypertensive medications, 24-h ambulatory BP monitoring (ABPM), echocardiogram, and ultrafiltration-associated symptoms. Sixteen of 20 enrolled patients completed the study. No difference was seen between baseline and 6-mo weight, predialysis casual BP, nighttime ABPM, or left ventricular mass index. There was a decrease in postdialysis casual systolic BP, daytime ABPM, number of antihypertensive medications prescribed, and rate of intradialytic events related to ultrafiltration (all P < or = 0.05). Adoption of a standardized NIVM-guided algorithm led to (1) improved ABPM profiles, (2) decreased antihypertensive medication burden, and (3) decreased ultrafiltration-associated symptoms. Wider use of NIVM-guided ultrafiltration may decrease cardiovascular morbidity in pediatric hemodialysis patients.

Cardiovascular risk factors in adolescents

Most children who are normal weight for height and otherwise healthy have risk factor levels associated with the absence of heart disease (ie, they do not smoke, do not have diabetes, are physically active, have low-density lipoprotein levels < 110 mg/dL, and have blood pressure < 120/80 mm Hg). However, by adolescence, the earliest lesions in the atherosclerotic process, fatty streaks and raised lesions, are present in the coronary arteries and the abdominal aorta. The severity of early atherogenesis is related to the coexistence of the major cardiovascular risk factors. Most commonly, the associated risk disturbances are mild: borderline hypertension, mild dyslipidemia, insulin resistance, overweight, physical inactivity, and initiation of tobacco use. Rarely, more severe risk factors are present: familial hypercholesterolemia (a genetic disorder of lipid metabolism), diabetes mellitus, secondary hypertension of long standing, or risk factors associated with chronic conditions such as end-stage renal disease. Thus, cardiovascular risk management in this age group has two components: primordial prevention (the prevention of the development of cardiovascular risk in the first place) and primary prevention (more aggressive treatment of identified risk factors in high-risk individuals either through behavioral or pharmacologic means). Trials beginning in adolescence of the primary prevention of atherosclerosis-related diseases have not been undertaken; thus, the decision to initiate pharmacologic management in high-risk adolescents requires careful thought.

Oxidative stress, inflammation and early cardiovascular damage in children with chronic renal failure

The relationship between inflammation, oxidant stress and cardiovascular damage in children with chronic renal failure (CRF) has not previously been investigated. The aim of this study was to investigate markers of oxidative stress, inflammation and early cardiovascular abnormalities. Therefore, erythrocyte superoxide dismutase (SOD) and catalase (CAT) activities; blood glutathione (GSH) and serum malondialdehyde (MDA) levels; C-reactive protein (CRP) and proinflammatory cytokines (IL-6, TNF-alpha,); and left ventricular masses (LVM) and intima media thicknesses (IMT) were measured in children with CRF. A total of 29 children with CRF (19 nondialysis, 10 peritoneal dialysis) were included. The control group consisted of 25 healthy subjects. CRF children had significantly increased IL-6, TNF-alpha, CRP and MDA concentrations and decreased SOD, CAT and GSH levels compared with controls (P<0.05). Nondialysis and peritoneal dialysis subgroups had similar oxidative stress and inflammation biomarkers (P>0.05). Erythrocyte CAT was positively correlated with CRP, TNF-alpha, and IL2-R in the study group. Positive correlations were found between cytokine concentrations, CRP and urea/creatinine levels. Significantly increased LVM and IMT values were found in CRF children (P<0.05). In conclusion, increased oxidant stress and inflammation together with early cardiovascular damage were found in CRF children. Further studies with more patients are needed to verify these results.