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

Intraoperative transit time flow measurement predicts maturation of radiocephalic arteriovenous fistulas

OBJECTIVE

The arteriovenous fistula (AVF) is the first choice for gaining vascular access for hemodialysis. However, 20% to 50% of AVFs fail within 4 months after creation. Although demographic risk factors have been described, there is little evidence on the intraoperative predictors of AVF maturation failure. The aim of this study was to assess the predictive value of intraoperative transit time flow measurements (TTFMs) on AVF maturation failure.

METHODS

In this retrospective cohort study, intraoperative blood flow, measured using TTFM, was compared with AVF maturation after 6 weeks in 55 patients. Owing to its significantly higher prevalence and risk of nonmaturation, the radiocephalic AVF (RCAVF) was the main focus of this study. A recommended cutoff point for high vs low intraoperative blood flow was determined for RCAVFs, using a receiver operating characteristic curve.

RESULTS

The average intraoperative blood flow in RCAVFs was 156 mL/min. Patients with an intraoperative blood flow equal or lower than the determined cutoff point of 160 mL/min, showed a 3.03 times increased risk of AVF maturation failure after 6 weeks, compared with patients with a higher intraoperative blood flow (P < .001).

CONCLUSIONS

The intraoperative blood flow in RCAVFs measured by TTFM provides an adequate means of predicting AVF nonmaturation 6 weeks after surgery. For RCAVFs, a cutoff point for intraoperative blood flow of 160 mL/min is recommended for maximum sensitivity and specificity to predict AVF maturation failure after 6 weeks.

Clinical practice recommendations on lipoprotein apheresis for children with homozygous familial hypercholesterolaemia: An expert consensus statement from ERKNet and ESPN

Homozygous familial hypercholesterolaemia is a life-threatening genetic condition, which causes extremely elevated LDL-C levels and atherosclerotic cardiovascular disease very early in life. It is vital to start effective lipid-lowering treatment from diagnosis onwards. Even with dietary and current multimodal pharmaceutical lipid-lowering therapies, LDL-C treatment goals cannot be achieved in many children. Lipoprotein apheresis is an extracorporeal lipid-lowering treatment, which is used for decades, lowering serum LDL-C levels by more than 70% directly after the treatment. Data on the use of lipoprotein apheresis in children with homozygous familial hypercholesterolaemia mainly consists of case-reports and case-series, precluding strong evidence-based guidelines. We present a consensus statement on lipoprotein apheresis in children based on the current available evidence and opinions from experts in lipoprotein apheresis from over the world. It comprises practical statements regarding the indication, methods, treatment goals and follow-up of lipoprotein apheresis in children with homozygous familial hypercholesterolaemia and on the role of lipoprotein(a) and liver transplantation.

Antibiotic lock solutions as adjunct therapy for catheter-related blood stream infections in pediatric hemodialysis patients

The predominant use of intravenous catheters as primary access type in the pediatric hemodialysis population is associated with an increased risk of catheter related blood stream infections. While strict adherence to catheter placement and long-term care guidelines have helped to decrease the incidence of these infections, blood stream infections remain an infection burden in pediatric patients with long term hemodialysis catheters. The formation of biofilms on the surfaces of these catheters has been shown to be a source of microbes causing blood stream infections. One of the strategies for preventing bacterial colonization, inhibiting microbial multiplication, and suppressing the seeding of these microbes from biofilms upon maturation, has been the use of antibiotic-based lock solutions in-between dialysis treatments. Although clinical guidelines for the use of antibiotic lock solutions are yet to be developed, available evidence suggests a beneficial role of antibiotic lock solutions in the management of catheter related blood stream infections. Additionally, a clear understanding of how biofilms are formed and their role in the pathogenesis of catheter related bloodstream infection will facilitate the development of solutions that can prevent biofilm formation and inhibit their multiplication, maturation and seeding into the bloodstream.

Case Report: Vascular access in paediatric haemodialysis patients-creating and maintaining the patency of an arteriovenous fistula

Introduction

Paediatric vascular access is a demanding field. The need for a multidisciplinary team is mandatory in children with end-stage kidney disease (ESKD). Central venous catheters (CVCs) remain the preferred option worldwide. Recent emerging data demonstrated the benefits of using arteriovenous fistulas (AVFs) in the paediatric population for long-term vascular access. The small vessel size in children represents a surgical challenge for vascular access.

Case presentation

We report three cases from our haemodialysis department and the difficulty in maintaining permanent vascular access. The first case is an adolescent girl who required a change in vascular approach after multiple central venous catheter (CVC) infections and catheter thrombosis secondary to thrombophilia. Three AVFs were performed but failure occurred early. The patient was also diagnosed with a complex vascular thrombosis with total occlusion of the inferior vena cava and completed distal thrombosis of the superior vena cava. A permanent CVC was placed in the right jugular vein with the tip in the azygos vein. The second case is of an adolescent boy with systemic vasculitis with multiple CVC infections secondary to immunosuppression. The first thrombosis of two right AVFs occurred early with the development of a pseudo-aneurysm that required surgical intervention. The left brachial-cephalic fistula required surgery for closing the collaterals, repositioning and superficialisation. The third case is an adolescent boy with one surgical stage brachial-basilic left AVF and difficulties in venous puncturing.

Conclusion

Vascular access in paediatric haemodialysis remains a demanding field. There is a need for a multidisciplinary team, consisting of a vascular surgeon and an interventional radiologist specialising in children.

Creating hemodialysis autogenous access in children and adolescents

OBJECTIVE

End-stage renal disease (ESRD) in childhood and adolescence is rare, with relatively few published reports of pediatric ESRD vascular access. This study analyzes a 10-year experience creating arteriovenous fistulas (AVFs) in children and adolescents. Our goal is to review our strategy for creating functional autogenous vascular access in younger patients and report our results.

METHODS

We retrospectively reviewed data and outcomes for consecutive vascular access patients aged ≤19 years during a 10-year period. Each patient had preoperative vascular ultrasound mapping by the operating surgeon in addition to physical examination. A distal forearm radiocephalic AVF was the first access choice when feasible, and a proximal radial artery inflow AVF was the next option. Demographic data, inflow artery, venous outflow target, and required transposition vs direct AVFs were variables included in the analysis. Primary and cumulative patency were calculated by Kaplan-Meier analysis.

RESULTS

Thirty-seven AVFs were created in 35 patients. No grafts were used. Ages were 6 to 19 years (mean, 15 years), and 20 were male. Causes of ESRD included glomerular disease (n = 18) and urinary obstruction or reflux (n = 7), among others. Three had previous AVFs, and 10 were obese. The proximal radial artery supplied AVF inflow in 25 patients and the brachial artery in only seven. Eleven individuals required a transposition and one a vein translocation to the contralateral arm. No patients developed hand ischemia, although two later required banding procedures for high flow. Eleven patients had successful transplants. A single patient died, unrelated to the vascular access. Five AVFs failed. Of these, two had new successful AVFs created, two regained renal function, one was transplanted, and one declined other procedures. Primary and cumulative patency rates were 75% and 85% at 12 months, 70% and 85% at 24 months, and 51% and 85% at 36 months, respectively. Median follow-up was 16 months.

CONCLUSIONS

Creating an AVF for hemodialysis is a successful vascular access strategy for pediatric and adolescent patients. Proximal radial artery AVFs provided safe and functional access when a distal AVF was not feasible. Cumulative AVF patency was 85% at 36 months.

Exchange of Extracorporeal Membrane Oxygenation Cannulas for Hemodialysis Catheters in Children Requiring Renal Replacement Therapy

BACKGROUND

Pediatric patients requiring extracorporeal membrane oxygenation (ECMO) may require renal replacement therapy even after decannulation. However, data regarding transition from ECMO cannulation to a hemodialysis catheter in pediatric patients is not currently available.

METHODS

Patients <18 years old who had an ECMO cannula exchanged for a hemodialysis catheter during decannulation at a tertiary care children's center from January 2011 to September 2022 were identified. Data was collected from the electronic medical record.

RESULTS

A total of 10 patients were included. The cohort was predominantly male (80.0%, n = 8) with a median age of 1 day (IQR 1.0, 24.0). All ECMO cannulations were veno-arterial in the right common carotid artery and internal jugular vein. The median time on ECMO was 8.5 days (IQR 6.0, 15.0). One patient had the venous cannula exchanged for a tunneled hemodialysis catheter during decannulation, two were transitioned to peritoneal dialysis, and seven had the temporary hemodialysis catheter converted to a tunneled catheter by Interventional Radiology (when permanent access was required) at a median time of 10 days (IQR 8.0, 12.5). Of these 7 patients, 28.6% (n = 2) developed catheter-associated infection within 30 days of replacement, with one requiring catheter replacement. Transient bloodstream infection occurred in 10.0% (n = 1) within 30 days of ECMO cannula exchange.

CONCLUSION

Venous ECMO cannula exchange for a hemodialysis catheter in children requiring renal replacement therapy after decannulation is possible as a bridge to a permanent hemodialysis or peritoneal catheter if renal function does not recover, while supporting vein preservation.

Vascular access challenges in hemodialysis children

BACKGROUND

Hemodialysis (HD) success is dependent mainly on vascular access (VA). The aim of this study is to share the experience of Pediatric Nephrology Unit (PNU), Cairo University Children's Hospital (CUCH), with VA-related obstacles in end stage kidney disease (ESKD) HD children.

METHODS

This is a retrospective analysis of VA related data of 187 ESKD children received regular HD over 3 year duration (2019-2021). Kaplan-Meier curves were used to present arteriovenous fistula (AVF) and cuffed catheters survivals.

RESULTS

Uncuffed central venous catheter (CVC) was the primary VA for HD in up to 97.3% with 2.7% of patients had AVF performed and attained maturation before initiation of regular HD. Fifty-six (29.9%) patients have inserted 120 tunneled CVCs. AVFs & AV grafts (AVF) were performed in 79 (42.2%) and 6 (3.2%) patients respectively. There were 112 uncuffed CVCs implanted beneath the screen in Rt internal jugular vein (IJV) (44%) Lt IJV (17%), right internal mammary vein (2.7%) while Trans hepatic (TH) technique was used to place 39 uncuffed CVCs (34%) in the inferior vena cava (IVC). Catheter-related bacteremia (CRB) was the most frequent complication in uncuffed and cuffed CVCs (2.58 / 100 catheters day and 10.1 /1000 catheter days respectively). AVFs achieved a high success rate (83%) after 757.71 ± 512.3 functioning days.

CONCLUSION

Native AVF is the preferred VA for pediatric HD but its creation is limited by the small sized vessels where non-cuffed CVC could be a reasonable relatively long-term alternative. Challenging situations (occluded central veins) could benefit from TH technique of CVC insertion in IVC.

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.

Clinical practice recommendations on lipoprotein apheresis for children with homozygous familial hypercholesterolemia: an expert consensus statement from ERKNet and ESPN

Homozygous familial hypercholesterolaemia is a life-threatening genetic condition, which causes extremely elevated LDL-C levels and atherosclerotic cardiovascular disease very early in life. It is vital to start effective lipid-lowering treatment from diagnosis onwards. Even with dietary and current multimodal pharmaceutical lipid-lowering therapies, LDL-C treatment goals cannot be achieved in many children. Lipoprotein apheresis is an extracorporeal lipid-lowering treatment, which is well established since three decades, lowering serum LDL-C levels by more than 70% per session. Data on the use of lipoprotein apheresis in children with homozygous familial hypercholesterolaemia mainly consists of case-reports and case-series, precluding strong evidence-based guidelines. We present a consensus statement on lipoprotein apheresis in children based on the current available evidence and opinions from experts in lipoprotein apheresis from over the world. It comprises practical statements regarding the indication, methods, treatment targets and follow-up of lipoprotein apheresis in children with homozygous familial hypercholesterolaemia and on the role of lipoprotein(a) and liver transplantation.

Changes in vascular access profile for pediatric hemodialysis patients over time: A registry-based study from Catalonia

BACKGROUND

The criteria for vascular access (VA) selection in pediatric hemodialysis (HD) population has changed over time until the current patient-centered approach using the individualized Life-Plan. We analyzed the type of VA used by incident and prevalent end-stage kidney disease (ESKD) pediatric patients (pts) treated with HD in Catalonia.

METHOD

Data from the Catalan Renal Registry of ESKD pts under 18 years of age undergoing kidney replacement therapy (KRT) were examined for a 22-year period (1997-2018).

RESULTS

ESKD children starting KRT through HD decreased progressively from 55.6% (1997-2001) to 38.2% (2012-2018) and, conversely, there was an increase in pts starting KRT by preemptive kidney transplantation (KT) from 28.9% to 42.6% between the same periods (for both comparisons, p = 0.007). Most ESKD pts started HD by fistula (AVF) from 1997 to 2001 (56.5%) but this percentage decreased over time and no AVFs were used to start HD in children from 2012 to 2018. Likewise, the percentage of children starting HD by tunneled catheter increased progressively from 8.7% to 72.2% between the same periods (for both comparisons, p < 0.001). Regarding prevalent ESKD pts, children on HD decreased from 34.9% in 1997 to 4.7% in 2018 and, conversely, pts with a functioning kidney graft increased from 62.8% to 92.4% during the same periods (for both comparisons, p < 0.001). There was a progressive decrease in the percentage of children dialyzed by AVF from 100% in 1997 to 0% in 2018 (p < 0.001). The KT rate increased from 5.4 per million population (pmp) in 1997 to 17.1 pmp in 2018 (p = 0.007). The median time on HD prior to the first KT progressively decreased to 6.6 months (2014-2018).

CONCLUSION

The high KT rate was a determining factor in choosing the VA type in the incident and prevalent pediatric population treated with HD in Catalonia.

Validating a novel three-times-weekly post-hemodialysis ceftriaxone regimen in infected Indigenous Australian patients-a population pharmacokinetic study

OBJECTIVES

To describe the total and unbound population pharmacokinetics of a 2 g three-times-weekly post-dialysis ceftriaxone regimen in Indigenous Australian patients requiring hemodialysis.

METHODS

A pharmacokinetic study was carried out in the dialysis unit of a remote Australian hospital. Adult Indigenous patients on intermittent hemodialysis (using a high-flux dialyzer) and treated with a 2 g three-times-weekly ceftriaxone regimen were recruited. Plasma samples were serially collected over two dosing intervals and assayed using validated methodology. Population pharmacokinetic analysis and Monte Carlo simulations were performed using Pmetrics in R. The probability of pharmacokinetic/pharmacodynamic target attainment (unbound trough concentrations ≥1 mg/L) and toxicity [trough concentrations (total)  ≥100 mg/L] were simulated for various dosing strategies.

RESULTS

Total and unbound concentrations were measured in 122 plasma samples collected from 16 patients (13 female) with median age 57 years. A two-compartment model including protein-binding adequately described the data, with serum bilirubin concentrations associated (inversely) with ceftriaxone clearance. The 2 g three-times-weekly regimen achieved 98% probability to maintain unbound ceftriaxone concentrations ≥1 mg/L for a serum bilirubin of 5 µmol/L. Incremental accumulation of ceftriaxone was observed in those with bilirubin concentrations >5 µmol/L. Three-times-weekly regimens were less probable to achieve toxic exposures compared with once-daily regimens. Ceftriaxone clearance was increased by >10-fold during dialysis.

CONCLUSIONS

A novel 2 g three-times-weekly post-dialysis ceftriaxone regimen can be recommended for a bacterial infection with an MIC ≤1 mg/L. A 1 g three-times-weekly post-dialysis regimen is recommended for those with serum bilirubin ≥10 µmol/L. Administration of ceftriaxone during dialysis is not recommended.

Impact of Isometric Exercise in Adolescents With End Stage Kidney Disease and Unsuitable Vessels For An Autologous Arteriovenous Fistula

INTRODUCTION

Despite the lack of calcification, to perform a native Arteriovenous Fistula (AVF) in young patients may pose a challenge due to small vessel diameter. We report a case series with no options of AVF in which vessel caliber improvement after isometric exercise allowed for radiocephalic fistula creation in all of them.

METHODS

Since 2017 to 2019, four patients were referred to our unit to create an AVF. Following a first assessment with physical examination and doppler ultrasound, none of them were eligible for AVF performance due to small vessel caliber. Once they were considered unsuitable for it, they started an isometric exercise program.

RESULTS

Age ranged from 13 to 19 years. There were three males and one female. Two were in predialysis and two in hemodialysis program. Initial diameters of the forearm cephalic vein and the radial artery respectively were: case A < 1.5/2.3 mm, case B 1.5/1.6 mm, case C < 1.5/1.6 mm and case D 2.1/1.3 mm. Median duration of exercise program was 13 weeks (range 5-23). Post-exercise vessel diameters were: case A 2.7/2.3 mm, case B 2.5/2 mm, case C 2.8/1.8 mm and case D 2.7/2 mm. Radiocephalic AVF were performed in the four cases. After a median follow up of 19 months (range 9-30 months), 75% of patients required further interventions but all of them had a functional AVF.

CONCLUSIONS

In these four cases isometric preoperative exercise allowed the creation of AVF. Without the improvement in vessel diameter observed afterwards, all of them would have been rejected for AVF performance. Despite the high rate of adjunctive interventions needed, given the safety of the program and the potential risks of Central Venous Catheters, we consider it a valuable option.

Good outcomes for arteriovenous fistula with buttonhole cannulation for chronic hemodialysis in children and adolescents

BACKGROUND

Arteriovenous fistula (AVF) is the preferred access for chronic hemodialysis (HD) in children and adolescents, but central venous catheter use is still high.

METHODS

Retrospective chart review of children and adolescents with AVF created between January 2003 and December 2015 was performed to assess primary failure (PF), maturation time, functional primary and functional cumulative patency, and potential risk factors for AVF dysfunction.

RESULTS

Ninety-nine AVF were created in 79 patients (54% male; 7-24 years; 16-147 kg) by experienced surgeons. Duplex ultrasonography vein mapping was used to assist with site selection. PF occurred in 17 AVF (17%) in 14 patients. Patient age, gender, ethnicity, underlying disease, time on dialysis, and AVF site were not associated with PF or patency. Coagulation abnormality was positively associated with PF (p = 0.03). Function was achieved in 82 AVF (83%) in 77 patients (97%). Median maturation time was 83 days (range 32-271). AVF were accessed via buttonholes. Functional primary patency was 95%, 84%, and 53% at 1, 2, and 5 years. Overall 1- and 2-year functional cumulative patency was 95%, but lower for small patients 16-30 kg (88%) and those greater than 80 kg (91%). The 5-year patency rate was 80%, but significantly lower for 16-30 kg (59%) and greater than 80 kg (55%). Risk analysis showed significantly better patency for 31-45 kg and 46-80 kg groups (p < 0.01), non-obese BMI (p = 0.01), and buttonhole self-cannulation (p = 0.03).

CONCLUSIONS

This study provides more information about successful AVF with buttonhole cannulation in pediatric hemodialysis patients lending additional support for AVF use in pediatrics. A higher resolution version of the Graphical abstract is available as Supplementary information.

The effects of hospital and dialysis unit characteristics on hospitalizations for access-related complications among children on maintenance dialysis: a European, multicenter, observational, cross-sectional study

BACKGROUND

Previous studies investigating hospitalizations in dialysis patients have focused primarily on patient-centered factors. We analyzed the impact of hospital and dialysis unit characteristics on pediatric dialysis patients' hospitalizations for access-related complications (ARCs).

METHODS

This cross-sectional study involved 102 hemodialysis (HD) and 163 peritoneal dialysis (PD) patients. Data between July 2017 and July 2018 were analyzed.

RESULTS

Children's hospitals (CHs) had more pediatric nephrologists and longer PD experience (years) than general hospitals (GHs) (p = 0.026 and p = 0.023, respectively). A total of 53% of automated PD (APD) and 6% of continuous ambulatory PD (CAPD) patients were in CHs (p < 0.001). Ninety-three percent of APD and 69% of CAPD patients were treated in pediatric-specific PD units (p = 0.001). CHs had a higher prevalence in providing hemodiafiltration (HDF) than GHs (83% vs. 30%). Ninety-seven percent of HDF vs. 66% for conventional HD (cHD) patients, and 94% of patients with arteriovenous fistula (AVF) vs. 70% of those with central venous catheters (CVC), were dialyzed in pediatric-specific HD units (p = 0.001 and p = 0.016, respectively). Eighty patients (51 PD and 29 HD) had 135 (84 PD, 51 HD) hospitalizations. CAPD was an independent risk factor for hospitalizations for infectious ARCs (I-ARCs) (p = 0.009), and a health center's PD experience negatively correlated with CAPD patient hospitalizations for I-ARCs (p = 0.041). cHD and dialyzing in combined HD units significantly increased hospitalization risk for non-infectious (NI-)ARCs (p = 0.044 and p = 0.017, respectively).

CONCLUSIONS

CHs and pediatric-specific dialysis units have higher prevalence of APD and HDF use. Hospitalizations for I-ARCs in CAPD are lower in centers with longer PD experience, and pediatric HD units are associated with fewer hospitalizations due to NI-ARCs. A higher resolution version of the Graphical abstract is available as Supplementary information.

Epidemiology and Risk Factors for Hemodialysis Access-Associated Infections in Children: A Prospective Cohort Study From the SCOPE Collaborative

RATIONALE & OBJECTIVE

Infections cause significant morbidity and mortality for children receiving maintenance hemodialysis (HD). The Standardizing Care to Improve Outcomes in Pediatric End-Stage Kidney Disease (SCOPE) Collaborative is a quality-improvement initiative aimed at reducing dialysis-associated infections by implementing standardized care practices. This study describes patient-level risk factors for catheter-associated bloodstream infections (CA-BSIs) and examines the association between dialysis center-level compliance with standardized practices and risk of CA-BSI.

STUDY DESIGN

Prospective cohort study.

SETTING & PARTICIPANTS

Children enrolled in SCOPE between June 2013 and July 2019.

EXPOSURES

Data were collected on patient characteristics and center-level compliance with HD catheter care practices across the study period. Centers were categorized as consistent, dynamic (improved compliance over the study period), or inconsistent performers based on frequency of compliance audit submission and changes in compliance with HD care practices over time.

OUTCOME

CA-BSIs.

ANALYTICAL APPROACH

Generalized linear mixed models were used to evaluate (1) patient-level risk factors for CA-BSI and (2) associations between change in center-level compliance and CA-BSIs.

RESULTS

The cohort included 1,277 children from 35 pediatric dialysis centers; 1,018 (79.7%) had a catheter and 259 (20.3%) had an arteriovenous fistula or graft. Among children with a catheter, mupirocin use at the catheter exit site was associated with an increased rate of CA-BSIs (rate ratio [RR], 4.45; P = 0.004); the use of no antibiotic agent at the catheter exit site was a risk factor of borderline statistical significance (RR, 1.79; P = 0.05). Overall median compliance with HD catheter care practices was 87.5% (IQR, 77.3%-94.0%). Dynamic performing centers showed a significant decrease in CA-BSI rates over time (from 2.71 to 0.71 per 100 patient-months; RR, 0.98; P < 0.001), whereas no significant change in CA-BSI rates was detected among consistent or inconsistent performers.

LIMITATIONS

Lack of data on adherence to HD care practices on the individual patient level.

CONCLUSIONS

Improvement in compliance with standardized HD care practices over time may lead to a reduction in dialysis-associated infections.

Clinical profile and outcome of arterio-venous fistulae in children on maintenance hemodialysis belonging to a low resource setting

INTRODUCTION

Arterio-venous fistula (AVF) is the recommended access of choice in children on maintenance hemodialysis. The challenges of creating and maintaining a fistula in children are many. The objective of our study was to study the clinical profile and outcomes of arteriovenous fistulae in children from a resource limited setting METHODS: A retrospective analysis of children who have had an AVF for maintenance hemodialysis from 2010 to 2020 was done. The centre protocol for creation and management of complications was followed. Failure of fistula to mature and failure to use fistula after it had been used were defined was primary failure and secondary failure respectively. Primary patency was defined as the time from maturation to first complication requiring intervention. The primary and secondary failure rates, risk factors for loss of primary patency and fistula survival were studied.

RESULTS

Thirty-six children (38 AVF) with median age of 11 (8,13) years were included. Brachio-cephalic anastomosis was the most common site (75%) of AVF. The primary and secondary failure rates were 5.5%(2/36) and 8.8%(3/34) respectively. The median time to loss of primary patency was 32 (16, 61.5) months. There were no particular risk factors identified for loss of primary patency. The 1- and 5-year survival was 91% and 73% respectively.

CONCLUSIONS

In resource limited settings, AVF is a feasible and durable access for maintenance hemodialysis in children with low failure rates.

Computational investigation of the haemodynamics shows criticalities of central venous lines used for chronic haemodialysis in children

BACKGROUND

Haemodialysis is a life-saving treatment for children with kidney failure. The majority of children have haemodialysis through central venous lines (CVLs). The use of CVLs in pediatric patients is often associated to complications which can lead to their replacement. The aim of this study is to investigate haemodynamics of pediatric CVLs to highlight the criticalities of different line designs.

METHODS

Four models of CVLs for pediatric use were included in this study. The selected devices varied in terms of design and sizes (from 6.5 Fr to 14 Fr). Accurate 3D models of CVLs were reconstructed from high-resolution images including venous and arterial lumens, tips and side holes. Computational fluid dynamics (CFD) analyses were carried out to simulate pediatric working conditions of CVLs in ideal and anatomically relevant conditions.

RESULTS

The arterial lumens of all tested CVLs showed the most critical conditions with the majority of blood flowing through the side-holes. A zone of low flow was identified at the lines' tip. The highest shear stresses distribution (>10 Pa) was found in the 8 Fr line while the highest platelet lysis index in the 10 Fr model. The analysis on the anatomical geometry showed an increase in wall shear stress measured in the 10 F model compared to the idealised configuration. Similarly, in anatomical models an increased disturbance and velocity of the flow was found inside the vein after line placement.

CONCLUSION

This study provided a numerical characterization of fluid dynamics in pediatric CVLs highlighting performance criticalities (i.e. high shear stresses and areas of stagnation) associated to specific sizes (8 Fr and 10 Fr) and conditions (i.e. anatomical test).

Outcomes of arteriovenous fistula for hemodialysis in pediatric age group

Introduction

The feasibility of arteriovenous fistula (AVF) creation in pediatric patients has long been documented, but few studies have evaluated the forms and long-term outcomes. The aim of this article is to highlight the types, techniques and outcomes of AVFs in pediatric age group.

Methods

This is multi-center, retrospective, single cohort study, including all the cases of pediatric (less than 18 year old) cases underwent AVF creation during four years (2015–2019). The following data were obtained from the patients' medical records and analyzed; socio-demographics, etiology of renal failure (RF), history of dialysis and transplantation, type and site of AVF, the outcomes and complications.

Results

The study included 108 patients, 89 patients (82.4%) were female. The mean age was 13 years. The most common cause of RF was the urological causes which were found in 34 cases (31.5%), followed by nephrotic syndrome (32 cases, 29.6%), glomerulonephritis (27 cases, 25%), and polycystic kidney disease (12 cases, 11.1%). The decision for choosing access site was performed only by clinical examination in 96 patients (88.9%) while duplex ultrasound was requested for 12 cases (11.1%). The operation was done under local anesthesia in 81 cases (75%) and general anesthesia in 27 cases (25%). The procedure was performed in the wrist in 58 cases (53.7%) and in cubital fossa in 50 cases (46.2%). The most common early complication was hematoma (12 cases, 11.1%), followed by ecchymosis (10 cases, 9.3%), infection (8, 7.4%), seroma (4, 3.7%) and thrombosis (3, 2.8%). The one-year primary patency rate was found in 95 patients (88%) and two-year patency rate in 86 patients (79.6%).

Conclusion

Native AVF in pediatric is the first choice dialysis access even in pediatric population. Radiocephalic in the non-dominant hand is the most preferred site.

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The feasibility of AVF creation in pediatric patients has long been documented.

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Few studies have evaluated the forms and long-term outcomes.

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Physical examination is an effective method for determining the proper site for access creation.

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The aim of this article is to highlight the types, techniques and outcome of AVFs in pediatric age group.

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.

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.

Sonographic 3-D Power Doppler Imaging Enhances Rapid Assessment of Morphologic and Pathologic Arteriovenous Fistula Variations

Early detection of pathologic variations in an arteriovenous fistula (AVF) is essential for preventing fistula dysfunction in individuals undergoing hemodialysis. This study aimed to evaluate the clinical applicability of 3-D tomographic ultrasound (tUS) for rapid and simple visualization of AVF morphology and pathology. We assessed 53 AVFs in 50 consecutive patients using 3-D tUS including secondary, blinded reading. For all examinations, a high-end ultrasound (US) device was used with linear probe, attached to a tUS system to allow freehand 3-D scanning. Participants were examined by 2-D US and 3-D tUS with different raw data (B-mode, power Doppler, B-flow). Additional angiography was available for 15 participants with scheduled interventions. In all participants, 3-D tUS allowed a 3-D representation of AVFs in angiographic-like images with good image quality. The 2-D US assessment took 7.9 ± 4.0 min. A 3-D power Doppler scan required, on average, 1.4 ± 0.6 min. Diagnostic accuracy of blinded reading for pathologies was high (86.8% for aneurysms and 79.2% for stenoses). Bland-Altman plots showed an excellent correlation of 3-D tUS with 2-D US and angiography. 3-D tUS is an easily and rapidly applicable method for visualizing morphologic and pathologic AVF variations. Color-coded 3-D reconstruction of power Doppler data simplifies detection of perfused aneurysms and stenoses.

"Save the Vein" Initiative in Children With CKD: A Quality Improvement Study

RATIONALE & OBJECTIVE

The preferred vascular access for hemodialysis recipients is an arteriovenous fistula in the nondominant arm. Prior placement of a peripheral intravenous (PIV) catheter can lead to vascular injury and limit options for arteriovenous fistula creation, a particular problem for children, who may need hemodialysis for their entire lifetime. We instituted an initiative to increase the frequency of PIV catheter placement in the dominant arm for hospitalized pediatric patients with advanced chronic kidney disease (CKD).

STUDY DESIGN

Quality improvement initiative.

SETTING & PARTICIPANTS

Children with CKD stage 3-5, receiving dialysis, and/or following kidney transplantation who were hospitalized at one children's hospital between September 2018 and August 2020.

QUALITY IMPROVEMENT ACTIVITIES

Retrospective data on PIV catheter location for patients from January 1 to June 30, 2017, served as baseline data. Quality improvement activities consisted of: 1) education of the multidisciplinary treatment team, patients, and parents regarding importance of vein preservation; 2) placement of individualized notes in the electronic medical record identifying the preferred arm for PIV catheter placement; 3) use of "restricted extremity" arm bands; and 4) vascular access team participation to minimize attempts for PIV catheter placement.

OUTCOME

Monthly compliance with placement of PIV catheters in dominant arms.

ANALYTICAL APPROACH

Location of PIV catheter placements were determined monthly and used to create run charts describing compliance.

RESULTS

At baseline and before institution of this initiative, 34 of 72 (47%) PIV catheters were placed in patients' dominant arms, with only 2 of 8 (25%) PIV catheters placed in the dominant arm for children aged<5 years. After instituting the initiative, 345 of 371 (93%) PIV catheters were placed in the dominant arm of 93 children; in children aged<5 years, 58 of 62 (94%) PIV catheters were placed in the dominant arm. Only 38 of 371 (10%) PIV catheters were placed in the antecubital vein.

LIMITATIONS

Single-center study.

CONCLUSIONS

Education regarding the importance of vein preservation, along with implementation of a standardized process for identifying children for whom vein preservation is important, can help direct PIV catheter placement and potentially preserve vasculature in pediatric patients with CKD.

Silent and dangerous: catheter-associated right atrial thrombus (CRAT) in children on chronic haemodialysis

BACKGROUND

Catheter-associated right atrial thrombus (CRAT) is a recognised complication of central venous catheter (CVC) use for haemodialysis (HD) patients.

METHODS

This was a single-centre retrospective longitudinal observational study of consecutive children aged 6 months-18 years over a 7-year period receiving in-centre chronic HD. Echocardiograms as per routine cardiac surveillance were performed 6 months or earlier given clinical concerns.

RESULTS

Sixty-five children, 36 boys (55.4%), median (IQR) age 11.8 (5.3, 14.7) years, received HD for kidney failure with replacement therapy (KFRT). Initial modality was HD in 45 (69.2%), with CVC as initial access in 42 (93.3%) and AVF in 3 (6.7%); in the remaining 20 (30.8%) patients PD was the initial modality before switching to HD. Seven of 65 (10.8%) developed CRAT at median 2 (0.8, 8.4) months from CVC insertion, with one CRAT detected 3 days following insertion. One child had 2 episodes of CRAT and one additionally thrombosed their AVF. No patient had an underlying primary kidney disease associated with a pro-thrombotic state. Those with CRAT were younger, had more frequent CVC change and received dialysis for longer duration compared to those with no CRAT. Six episodes of CRAT (75%) received anticoagulation therapy. Infective complications were observed in 25% and catheter malfunction in 50%. Five CRAT episodes (62.5%) resulted in CVC loss. One patient died after a haemorrhagic complication of anticoagulation and sepsis, and another developed life-threatening superior vena cava obstruction syndrome. Overall mortality 14% (1/7).

CONCLUSIONS

This is the first report of CRAT in a paediatric HD population. There was ~ 11% incidence of CRAT in patients receiving chronic HD detected by surveillance echocardiography. Although frequently asymptomatic, CRAT is associated with serious sequelae. Anticoagulation and surveillance with expert echocardiography remain mainstays of management. Graphical abstract.

Cardiovascular Outcome of Pediatric Patients With Bi-Allelic (Homozygous) Familial Hypercholesterolemia Before and After Initiation of Multimodal Lipid Lowering Therapy Including Lipoprotein Apheresis

Twenty-four patients with bi-allelic familial hypercholesterolemia commencing chronic lipoprotein apheresis (LA) at a mean age of 8.5 ± 3.1 years were analysed retrospectively and in part prospectively with a mean follow-up of 17.2 ± 5.6 years. Mean age at diagnosis was 6.3 ± 3.4 years. Untreated mean LDL-C concentrations were 752 mg/dl ± 193 mg/dl (19.5 mmol/l ± 5.0 mmol/l). Multimodal lipid lowering therapy including LA resulted in a mean LDL-C concentration of 184 mg/dl (4.8 mmol/l), which represents a 75.5% mean reduction. Proprotein convertase subtilisin/kexin type 9-antibodies contributed in 3 patients to LDL-C lowering with 5 patients remaining to be tested. After commencing chronic LA, 16 patients (67%) remained clinically stable with only subclinical findings of atherosclerotic cardiovascular disease (ASCVD), and neither cardiovascular events, nor need for vascular interventions or surgery. In 19 patients (79%), pathologic findings were detected at the aortic valve (AV), which in the majority were mild. AV replacement was required in 2 patients. Mean Lipoprotein(a) concentration was 42.4 mg/dl, 38% had >50 mg/dl. There was no overt correlation of AV pathologies with other ASCVD complications, or Lipoprotein(a) concentration. Physicochemical elimination of LDL particles by LA appears indispensable for patients with bi-allelic familial hypercholesterolemia and severe hypercholesterolemia to maximize the reduction of LDL-C. In conclusion, in this rare patient group regular assessment of both the AV, as well as all arteries accessible by ultrasound should be performed to adjust the intensity of multimodal lipid lowering therapy with the goal to prevent ASCVD events and aortic surgery.

Challenges of long-term vascular access in pediatric hemodialysis: Recommendations for practitioners

Kidney transplantation is the preferred treatment of end-stage renal disease in children. However, time to transplant varies, making a well-functioning long-term vascular access essential for performing hemodialysis efficiently and without disruption until a kidney becomes available. However, establishing long-term vascular access in pediatric patients can present distinct challenges due to this population's unique characteristics, such as smaller body size and lower-diameter blood vessels. There are three main pediatric long-term vascular access options, which include central venous catheters (CVC), arteriovenous fistula (AVF), and arteriovenous graft (AVG). CVC are currently the most widely used modality, although various studies and guidelines recommend AVF or AVG as the preferred option. Although AVF should be used whenever possible, it is crucial that clinicians consider factors such as patient size, physical exam findings, comorbidities, predicted duration of treatment to decide on the most optimal long-term vascular access modality. This article reviews the three long-term vascular access methods in children and the benefits and complications of each.

Predictors of time to first cannulation for arteriovenous fistula in pediatric hemodialysis patients: Midwest Pediatric Nephrology Consortium study

BACKGROUND

Permanent vascular access (PVA) is preferred for long-term hemodialysis. Arteriovenous fistulae (AVF) have the best patency and the lowest complication rates compared to arteriovenous grafts (AVG) and tunneled cuffed catheters (TCC). However, AVF need time to mature. This study aimed to investigate predictors of time to first cannulation for AVF in pediatric hemodialysis patients.

METHODS

Data on first AVF and AVG of patients at 20 pediatric dialysis centers were collected retrospectively, including demographics, clinical information, dialysis markers, and surgical data. Statistical modeling was used to investigate predictors of outcome.

RESULTS

First PVA was created in 117 children: 103 (88%) AVF and 14 (12%) AVG. Mean age at AVF creation was 15.0 ± 3.3 years. AVF successfully matured in 89 children (86.4%), and mean time to first cannulation was 3.6 ± 2.5 months. In a multivariable regression model, study center, age, duration of non-permanent vascular access (NPVA), and Kt/V at AVF creation predicted time to first cannulation, with study center as the strongest predictor (p < 0.01). Time to first cannulation decreased with increasing age (p = 0.03) and with increasing Kt/V (p = 0.01), and increased with duration of NPVA (p = 0.03). Secondary failure occurred in 10 AVF (11.8%). Time to first cannulation did not predict secondary failure (p = 0.29), but longer time to first cannulation tended towards longer secondary patency (p = 0.06).

CONCLUSIONS

Study center is the strongest predictor of time to first cannulation for AVF and deserves further investigation. Time to first cannulation is significantly shorter in older children, with more efficient dialysis treatments, and increases with longer NPVA duration.

Tunneled hemodialysis catheter care practices and blood stream infection rate in children: results from the SCOPE collaborative

OBJECTIVE

The Standardizing Care to Improve Outcomes in Pediatric End Stage Renal Disease (SCOPE) collaborative seeks to reduce hemodialysis (HD) catheter-associated blood stream infections (CA-BSI) by increasing implementation of standardized HD catheter care bundles. We report HD catheter care practices and HD CA-BSI rates from SCOPE.

METHODS

Catheter care practices and infection events were collected prospectively during the study period, from collaborative implementation in June 2013 through May 2017. For comparative purposes, historical data, including patient demographics and HD CA-BSI events, were collected from the 12 months prior to implementation. Catheter care bundle compliance in 5 care bundle categories was monitored across the post-implementation reporting period at each center via monthly care observation forms. CA-BSI rates were calculated monthly, and reported as number of infections per 100 patient months. Changes in CA-BSI rates were assessed using generalized linear mixed model (GLMM) techniques.

RESULTS

Three hundred twenty-five patients with tunneled HD catheters [median (IQR) age 12 years (6, 16), M 53%, F 47%] at 15 centers were included. A total of 3996 catheter care observations over 4170 patient months were submitted with a median (IQR) 5 (2, 14) observations per patient. Overall bundle compliance was high at 87.6%, with a significant and progressive increase (p < 0.001) in compliance for 4/5 bundle categories over the 48-month study period. The adjusted CA-BSI rate significantly decreased over time from 3.3/100 patient months prior to implementation of the care bundles to 0.8/100 patient months 48 months after care bundle implementation (p < 0.001).

CONCLUSIONS

Using quality improvement methodology, SCOPE has demonstrated a significant increase in compliance with a majority of HD catheter care practices and a significant reduction in the rate of CA-BSI among children maintained on HD.

Ultrasound dilution and thermodilution versus color Doppler ultrasound for arteriovenous fistula assessment in children on hemodialysis

BACKGROUND

This study is aimed at comparing ultrasound dilution (UD) and thermodilution (TD) with color Doppler ultrasound (CDU) for arteriovenous fistula (AVF) assessment in children on hemodialysis (HD).

MATERIAL AND METHODS

All patients were dialysed with the Fresenius 5008 HD machine. UD was performed using the Transonic device. The two methods were compared with CDU performed on a non-HD day. AVF flow rate was expressed as ml/min/1.73 m².

RESULTS

Sixteen measurements of AVF flow rate and recirculation with UD and TD were compared with CDU in 16 patients with a median weight of 39 kg. Both UD and TD overestimated AVF flow rate when compared with CDU (+437 (95% CI + 200, + 674) and + 476 (95% CI + 80, + 871) ml/min/1.73 m² for UD and TD, respectively). CDU flow rate was significantly correlated to UD flow rate (r² = 0.761, p < 0.001), but not to TD flow rate (r² = 0.164, p = 0.120). Although recirculation in all AVF was estimated to be 0% and < 15% with UD and TD, respectively, 7 significant stenoses were diagnosed by CDU. AVF with stenosis had lower flow rates when measured by CDU, UD or TD, but only CDU measurements reached statistical significance (p = 0.008, p = 0.142 and p = 0.174, respectively).

CONCLUSION

UD and TD overestimate AVF flow rate when compared with CDU, which is the most reliable non-invasive method for screening vascular access for stenosis. UD seems more accurate than TD for AVF flow rate assessment. Recirculation via UD or TD should not be used for early screening of AVF stenosis in children on HD.