Hemodiafiltration for children with stage 5 chronic kidney disease: technical aspects and outcomes.

Despite significant medical and technical improvements in the field of dialysis, the morbidity and mortality among patients with chronic kidney disease (CKD) stage 5 on dialysis remains extremely high. Hemodiafiltration (HDF), a dialysis method that combines the two main principles of hemodialysis (HD) and hemofiltration-diffusion and convection-has had a positive impact on survival when delivered with a high convective dose. Improved outcomes with HDF have been attributed to the following factors: HDF removes middle molecular weight uremic toxins including inflammatory cytokines, increases hemodynamic stability, and reduces inflammation and oxidative stress compared to conventional HD. Two randomized trials in adults have shown improved survival with HDF compared to high-flux HD. A large prospective cohort study in children has shown that HDF attenuated the progression of cardiovascular disease, improved bone turnover and growth, reduced inflammation, and improved blood pressure control compared to conventional HD. Importantly, children on HDF reported fewer headaches, dizziness, and cramps; had increased physical activity; and improved school attendance compared to those on HD. In this educational review, we discuss the technical aspects of HDF and results from pediatric studies, comparing outcomes on HDF vs. conventional HD. Convective volume, the cornerstone of treatment with HDF and a key determinant of outcomes in adult randomized trials, is discussed in detail, including the practical aspects of achieving an optimal convective volume.

Technical requirements and devices available for long-term hemodialysis in children-mind the gap!

Children requiring long-term kidney replacement therapy are a "rare disease" cohort. While the basic technical requirements for hemodialysis (HD) are similar in children and adults, key aspects of the child's cardiovascular anatomy and hemodynamic specifications must be considered. In this article, we describe the technical requirements for long-term HD therapy for children and the devices that are currently available around the world. We highlight the characteristics and major technical shortcomings of permanent central venous catheters, dialyzers, dialysis machines, and software available to clinicians who care for children. We show that currently available HD machines are not equipped with appropriately small circuits and sensitive control mechanisms to perform safe and effective HD in the youngest patients. Manufacturers limit their liability, and health regulatory agencies permit the use of devices, only in children according to the manufacturers' pre-specified weight limitations. Although registries show that 6-23% of children starting long-term HD weigh less than 15 kg, currently, there is only one long-term HD device that is cleared for use in children weighing 10 to 15 kg and none is available and labelled for use in children weighing less than 10 kg anywhere in the world. Thus, many children are being treated "off-label" and are subject to interventions delivered by medical devices that lack pediatric safety and efficacy data. Moreover, recent improvements in dialysis technology offered to adult patients are denied to most children. We, in turn, advocate for concerted action by pediatric nephrologists, industry, and health regulatory agencies to increase the development of dedicated HD machines and equipment for children.

Update on the creation and maintenance of arteriovenous fistulas for haemodialysis in children.

Arteriovenous fistulas (AVFs) are widely used for haemodialysis (HD) in adults with stage 5 chronic kidney disease (CKD 5) and are generally considered the best form of vascular access (VA). The 'Fistula First' initiative in 2003 helped to change the culture of VA in adults. However, this cultural change has not yet been adopted in children despite the fact that a functioning AVF is associated with lower complication rates and longer access survival than a central venous line (CVL). For children with CKD 5, especially when kidney failure starts early in life, there is a risk that all VA options will be exhausted. Therefore, it is essential to develop long-term strategies for optimal VA creation and maintenance. Whilst AVFs are the preferred VA in the paediatric population on chronic HD, they may not be suitable for every child. Recent guidelines and observational data in the paediatric CKD 5 population recommend switching from a 'Catheter First' to 'Catheter Last' approach. In this review, recent evidence is summarized in order to promote change in current practices.

Vascular access in children requiring maintenance haemodialysis: a consensus document by the European Society for Paediatric Nephrology Dialysis Working Group

There are three principle forms of vascular access available for the treatment of children with end stage kidney disease (ESKD) by haemodialysis: tunnelled catheters placed in a central vein (central venous lines, CVLs), arteriovenous fistulas (AVF), and arteriovenous grafts (AVG) using prosthetic orbiological material. Compared with the adult literature, there are few studies in children to provide evidence based guidelines for optimal vascular access type or its management and outcomes in children with ESKD.

Vascular access in children requiring maintenance haemodialysis: a consensus document by the European Society for Paediatric Nephrology Dialysis Working Group.

BACKGROUND: There are three principle forms of vascular access available for the treatment of children with end stage kidney disease (ESKD) by haemodialysis: tunnelled catheters placed in a central vein (central venous lines, CVLs), arteriovenous fistulas (AVF), and arteriovenous grafts (AVG) using prosthetic or biological material. Compared with the adult literature, there are few studies in children to provide evidence based guidelines for optimal vascular access type or its management and outcomes in children with ESKD. METHODS: The European Society for Paediatric Nephrology Dialysis Working Group (ESPN Dialysis WG) have developed recommendations for the choice of access type, pre-operative evaluation, monitoring, and prevention and management of complications of different access types in children with ESKD. RESULTS: For adults with ESKD on haemodialysis, the principle of "Fistula First" has been key to changing the attitude to vascular access for haemodialysis. However, data from multiple observational studies and the International Paediatric Haemodialysis Network registry suggest that CVLs are associated with a significantly higher rate of infections and access dysfunction, and need for access replacement. Despite this, AVFs are used in only ∼25% of children on haemodialysis. It is important to provide the right access for the right patient at the right time in their life-course of renal replacement therapy, with an emphasis on venous preservation at all times. While AVFs may not be suitable in the very young or those with an anticipated short dialysis course before transplantation, many paediatric studies have shown that AVFs are superior to CVLs. CONCLUSIONS: Here we present clinical practice recommendations for AVFs and CVLs in children with ESKD. The Grading of Recommendations Assessment, Development, and Evaluation (GRADE) system has been used to develop and GRADE the recommendations. In the absence of high quality evidence, the opinion of experts from the ESPN Dialysis WG is provided, but is clearly GRADE-ed as such and must be carefully considered by the treating physician, and adapted to local expertise and individual patient needs as appropriate.

Effects of Hemodiafiltration versus Conventional Hemodialysis in Children with ESKD: The HDF, Heart and Height Study.

BACKGROUND: Hypertension and cardiovascular disease are common in children undergoing dialysis. Studies suggest that hemodiafiltration (HDF) may reduce cardiovascular mortality in adults, but data for children are scarce. METHODS: The HDF, Heart and Height study is a nonrandomized observational study comparing outcomes on conventional hemodialysis (HD) versus postdilution online HDF in children. Primary outcome measures were annualized changes in carotid intima-media thickness (cIMT) SD score and height SD score. RESULTS: We enrolled 190 children from 28 centers; 78 on HD and 55 on HDF completed 1-year follow-up. The groups were comparable for age, dialysis vintage, access type, dialysis frequency, blood flow, and residual renal function. At 1 year, cIMT SD score increased significantly in children on HD but remained static in the HDF cohort. On propensity score analysis, HD was associated with a +0.47 higher annualized cIMT SD score compared with HDF. Height SD score increased in HDF but remained static in HD. Mean arterial pressure SD score increased with HD only. Factors associated with higher cIMT and mean arterial pressure SD-scores were HD group, higher ultrafiltration rate, and higher ß2-microglobulin. The HDF cohort had lower ß2-microglobulin, parathyroid hormone, and high-sensitivity C-reactive protein at 1 year; fewer headaches, dizziness, or cramps; and shorter postdialysis recovery time. CONCLUSIONS: HDF is associated with a lack of progression in vascular measures versus progression with HD, as well as an increase in height not seen in the HD cohort. Patient-related outcomes improved among children on HDF correlating with improved BP control and clearances. Confirmation through randomized trials is required.

Dalteparin anticoagulation in paediatric home haemodialysis.

BACKGROUND: The aim of this study was to investigate whether dalteparin is a safe and effective anticoagulant for paediatric home haemodialysis (HD) and to assess the determinants of dosing. METHODS: Data were collected for all children (< 18 years) undergoing home HD from 2011 to 2017 at one large paediatric nephrology centre in the UK. All children had anticoagulation with dalteparin sodium according to a standardised protocol. Dalteparin safety was assessed by monitoring for accumulation, adequate clearance of dalteparin and adverse events. Dalteparin efficacy was assessed through monitoring for clot formation in dialysis circuits. Potential determinants of dalteparin dosing were assessed. RESULTS: Eighteen children were included, their median age at start was 12 years, and 50% were male. Eighty-three percent of children had four home HD sessions each week, with a median total dialysis hours of 20 h/week. Thirty-three percent of children had nocturnal home HD. Median dalteparin dose at 12-month follow-up was 40 IU/kg (range 8-142 IU/kg). Factors associated with higher dalteparin dosing requirements included a younger age of the child (p < 0.01), a lower blood flow rate (p < 0.01) and the use of a central venous line for dialysis access (p = 0.038). No children had evidence of bioaccumulation of dalteparin or inadequate clearance. No significant bleeding or adverse events were reported. CONCLUSIONS: Dalteparin is a safe and effective anticoagulant when used for paediatric home HD. In this study, there was no evidence of bioaccumulation or significant adverse events. Further research is required to directly compare dalteparin with unfractionated heparin (UFH) and evaluate anticoagulant choice for paediatric home HD.

Assessing the hydration status of children with chronic kidney disease and on dialysis: a comparison of techniques.

Background: Fluid balance is pivotal in the management of children with chronic kidney disease (CKD) and on dialysis. Although many techniques are available to assess fluid status, there are only a few studies for children, of which none have been comparable against cardiovascular outcome measures. Methods: We performed a longitudinal study in 30 children with CKD5-5D and 13 age-matched healthy controls (71 measurements) to determine a correlation between optimal weight by bioimpedance spectroscopy (Wt-BIS) and clinical assessment (Wt-CA). The accuracy of Wt-BIS [relative overhydration (Rel-OH)] was compared against indicators of fluid status and cardiovascular measures. Results: There was poor agreement between Wt-CA and Wt-BIS in children on dialysis (P = 0.01), but not in CKD5 or control subjects. We developed a modified chart to plot Rel-OH against systolic blood pressure (SBP) z-score for the appropriate representation of volume status and blood pressure (BP) in children. In total, 25% of measurements showed SBP >90th percentile but not with concurrent overhydration. Rel-OH correlated with peripheral pulse pressure (P = 0.03; R = 0.3), higher N-terminal pro-brain natriuretic peptide (P = 0.02; R = 0.33) and left ventricular end-diastolic diameter (P = 0.05; R = 0.38). Central aortic mean and pulse pressure significantly associated with the left ventricular end-diastolic diameter (P = 0.03; R = 0.47 and P = 0.01; R = 0.50, respectively), but not with Rel-OH. SBP was positively associated with pulse wave velocity z-score (P = 0.04). In total, 40% of children on haemodialysis and 30% on peritoneal dialysis had increased left ventricular mass index. Conclusions: BIS provides an objective method for the assessment of hydration status in children on dialysis. We noted a marked discrepancy between BP and hydration status in children on dialysis that warrants further investigation.

A dedicated vascular access clinic for children on haemodialysis: Two years' experience.

BACKGROUND: Arteriovenous fistula (AVF) formation for long-term haemodialysis in children is a niche discipline with little data for guidance. We developed a dedicated Vascular Access Clinic that is run jointly by a transplant surgeon, paediatric nephrologist, dialysis nurse and a clinical vascular scientist specialised in vascular sonography for the assessment and surveillance of AVFs. We report the experience and 2-year outcomes of this clinic. METHODS: Twelve new AVFs were formed and 11 existing AVFs were followed up for 2 years. All children were assessed by clinical and ultrasound examination. RESULTS: During the study period 12 brachiocephalic, nine basilic vein transpositions and two radiocephalic AVFs were followed up. The median age (interquartile range) and weight of those children undergoing new AVF creation were 9.4 (interquartile 3-17) years and 26.9 (14-67) kg, respectively. Pre-operative ultrasound vascular mapping showed maximum median vein and artery diameters of 3.0 (2-5) and 2.7 (2.0-5.3) mm, respectively. Maturation scans 6 weeks after AVF formation showed a median flow of 1277 (432-2880) ml/min. Primary maturation rate was 83 % (10/12). Assisted maturation was 100 %, with two patients requiring a single angioplasty. For the 11 children with an existing AVF the maximum median vein diameter was 14.0 (8.0-26.0) mm, and the median flow rate was 1781 (800-2971) ml/min at a median of 153 weeks after AVF formation. Twenty-two AVFs were used successfully for dialysis, a median kt/V of 1.97 (1.8-2.9), and urea reduction ratio of 80.7 % (79.3-86 %) was observed. One child was transplanted before the AVF was used. CONCLUSIONS: A multidisciplinary vascular clinic incorporating ultrasound assessment is key to maintaining young children on chronic haemodialysis via an AVF.

Home hemodialysis in children.

Pediatric home hemodialysis is infrequently performed despite a growing need globally among patients with end-stage renal disease who do not have immediate access to a kidney transplant. In this review, we expand the scope of the Implementing Hemodialysis in the Home website and associated supplement published previously in Hemodialysis International and offer information tailored to the pediatric population. We describe the experience and outcomes of centers managing pediatric patients, and offer recommendations and practical tools to assist clinicians in providing quotidian dialysis for children, including infrastructural and staffing needs, equipment and prescriptions, and patient selection and training.

Intensified home haemodialysis for managing severe cardiac failure.

BACKGROUND: Conventional thrice weekly haemodialysis (HD) provides adequate dialysis to prevent mortality, but morbidity is prevalent in both the paediatric and adult population. There has been growing interest in the potential of intensive dialysis regimes entering the realm of optimal dialysis, with superior health and quality of life outcomes. CASE DIAGNOSIS/TREATMENT: We present the case of a 13-year-old girl who had bilateral nephrectomies as a result of bilateral Wilms tumors. In the third year of treatment with conventional HD, she presented with symptomatic progressive cardiac failure, presumably secondary to anthracycline-induced cardiomyopathy. Consequently, she was taken off the renal transplant list and became increasingly dependent on frequent in-centre dialysis sessions to manage her symptoms. Five months after switching to a frequent and extended home HD regime, we observed a tremendous improvement in her health and well-being, with complete reversal of her cardiac dysfunction. CONCLUSIONS: Home HD is a practically viable option in children with severe cardiac dysfunction. Gentler, more intensive dialysis will draw out and improve the ureamic component of heart disease. This may translate into improved cardiac function.

Home haemodialysis.

Haemodialysis (HD) began as an intensive care treatment offered to a very select number of patients in an attempt to keep them alive. Outcomes were extremely poor, and the procedure was cumbersome and labor intensive. With increasing expertise and advances in dialysis equipment, HD is now recognised as a life-sustaining treatment that is considered a standard of care for children with end stage renal disease (ESRD). Assessment of efficacy has evolved from mere survival, through achieving minimal standards of "adequate" dialysis with reduced morbidity, towards the provision of "optimal dialysis", which includes attempts to more closely mimic normal renal function, and of individualised care that maximizes the patient's health, psychosocial well-being and life potential. There is a renewed interest in dialysis, and the research profile has extended, exploring themes around convective versus diffusive treatments, HD time versus frequency and home versus in-centre dialysis. The results thus far have led dialysis care full circle from prolonged, home-based therapies to shorter, intense in-centre dialysis back to the belief that long or frequent HD at home achieves the best outcomes.