Hemodialysis vascular access options in pediatrics: considerations for patients and practitioners

Use of 4% tetrasodium EDTA (KiteLock™) to prevent central venous catheter-related bloodstream infections in pediatric hemodialysis patients

BACKGROUND

Central venous catheter (CVC)-related bloodstream infections (CRBSI) are common in children receiving hemodialysis and cause significant morbidity and healthcare costs. Unlike standard locking solutions, 4% tetrasodium EDTA (KiteLock™) has antimicrobial and antibiofilm properties. We aimed to study the safety and efficacy of 4% tetrasodium EDTA CVC locking in pediatric hemodialysis.

METHODS

Single-center, before-and-after quality improvement study. We included all chronic hemodialysis patients (6 months-18 years) from 2016-2022 (before) to 2022-2024 (after). The standard CVC locking solution was changed from heparin (1000 units/mL) to 4% tetrasodium EDTA. We compared unit-level incidence of CRBSI, CVC replacement procedures (exchange or removal and reinsertion), laboratory results, alteplase use, and adverse events before and after 4% tetrasodium EDTA implementation.

RESULTS

We included 22 pediatric chronic hemodialysis patients (median age 13.5 years, 50% female). CRBSI incidence was 0.89 infections per 1000 catheter-days (25,769 total catheter-days) before and 0.18 per 1000 catheter-days (5426 total catheter-days) after 4% tetrasodium EDTA (IRR 0.21, 95%CI 0.03-1.52). CVC replacement procedure incidence was 1.99 procedures per 1000 catheter-days (4027 total catheter-days) before and 1.29 per 1000 catheter-days (5426 total catheter-days) after 4% tetrasodium EDTA (IRR 0.65, 95%CI 0.24-1.79). There were no significant differences in hemodialysis treatment parameters, alteplase use (12% of treatments before vs. 18% after), or access complications (12% of treatments before vs. 15% after).

CONCLUSIONS

CVC locking with 4% tetrasodium EDTA was associated with sustained reductions in CRBSI and CVC replacement procedure incidence. Incorporation of 4% tetrasodium EDTA locking into standardized CVC care bundles may prolong vascular access survival.

Preparing a dialysis patient

Preparing a dialysis patient for access placement is a process that should ideally begin well before the need for access use. Unfortunately, this is often not the case and patients are often seen well after dialysis has been initiated with a catheter. The process should include a detail-oriented history and a thorough vascular oriented physical examination. A complete history and physical exam will help tailor access options in individual patients. The KDOQI guideline structures the selection and timing of dialysis access, ensuring each patient's medical circumstances and preferences are taken into account. The preparation of a dialysis patient should also include discussion with the patient in regard to their values and expectations before coming to a life-long plan for the patient. This holistic approach aims to achieve reliable and functioning access while preserving future options and improving patient outcomes. This following review will cover the elements of both as well as adjunctive imaging modalities and their indications to allow for successful access placement.

Long-Term Experience of Arterio-Venous Fistula Surgery in Children on Hemodialysis

Background: Arterio-venous fistulas (AVF) are used as first-line access for hemodialysis (HD) in the pediatric population. The aim of this investigation was to describe a single-center experience in the creation of AVF, together with its patency in children. Methods: This single-center retrospective study included all patients aged ≤18 years with AVFs created between 1993 and 2023. The collected data included patients' demographics, hemodialysis history, intraoperative data, and required reinterventions in order to determine the impact of these variables on primary, primary-assisted, and secondary patency. Results: Fifty-seven patients were analyzed with a median age of 15 years (range, 7-18 years). Fifty-four forearm and four upper arm fistulas were performed. The median follow-up was 6.9 years (range, 0-23 years). The primary failure rate was 10.5%. The primary patency rate was 67.6%, 53.6%, 51.4%, and 38.1% after 1, 3, 5, and 10 years; primary-assisted patency was 72.9%, 62.8%, 60.6%, and 41.5%; and secondary patency was 87.3%, 81.3%, 76.8%, and 66.6% after 1, 3, 5, and 10 years in the studied population. Conclusions: AVFs showed an acceptable rate of primary failure and excellent long-term patency. In this context, AVFs are an appropriate option for HD access, especially in pediatric patients.

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.

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.

"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.

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.

Practice patterns of dialysis access and outcomes in patients wait-listed early for kidney transplantation

BACKGROUND

Early kidney transplantation (KT) is the best option for patients with end-stage kidney disease, but little is known about dialysis access strategy in this context. We studied practice patterns of dialysis access and how they relate with outcomes in adults wait-listed early for KT according to the intended donor source.

METHODS

This study from the REIN registry (2002-2014) included 9331 incident dialysis patients (age 18-69) wait-listed for KT before or by 6 months after starting dialysis: 8342 candidates for deceased-donor KT and 989 for living-donor KT. Subdistribution hazard ratios (SHR) of KT and death associated with hemodialysis by catheter or peritoneal dialysis compared with arteriovenous (AV) access were estimated with Fine and Gray models.

RESULTS

Living-donor candidates used pretransplant peritoneal dialysis at rates similar to deceased-donor KT candidates, but had significantly more frequent catheter than AV access for hemodialysis (adjusted OR 1.25; 95%CI 1.09-1.43). Over a median follow-up of 43 (IQR: 23-67) months, 6063 patients received transplants and 305 died before KT. Median duration of pretransplant dialysis was 15 (7-27) months for deceased-donor recipients and 9 (5-15) for living-donor recipients. Catheter use in deceased-donor candidates was associated with a lower SHR for KT (0.88, 95%CI 0.82-0.94) and a higher SHR for death (1.53, 95%CI 1.14-2.04). Only five deaths occurred in living-donor candidates, three of them with catheter use.

CONCLUSIONS

Pretransplant dialysis duration may be quite long even when planned with a living donor. Advantages from protecting these patients from AV fistula creation must be carefully evaluated against catheter-related risks.

Left innominate vein creation using left internal jugular vein tunneled to right internal jugular vein

BACKGROUND

Left innominate vein occlusion is a known complication of pacemaker and central venous catheter placement. For dialysis-dependent patients with an arteriovenous fistula (AVF), this can prevent successful hemodialysis and may require surgical intervention.

CASE REPORT

An 8-month-old male was diagnosed with hemolytic uremic syndrome and became dialysis-dependent at 11 months of age. After multiple vascular access and peritoneal dialysis complications, the patient had construction of a brachiobasalic AVF in his left arm at 13 years old. While waiting for the AVF to mature, an attempt to remove a previously placed left subclavian vein port-a-cath was unsuccessful and a follow-up imaging revealed that the vessel had become occluded. The fistula remained patent, but due to arm swelling and venous obstruction, his fistula was not accessible. Multiple attempts to percutaneously cross the left innominate vein were unsuccessful and the patient was referred for surgical intervention. At 15 years old, the patient was taken to the operating room for transposition of the left internal jugular vein (LIJ) to the right internal jugular vein (RIJ). The LIJ was transected under the mandible and anastomosed to the RIJ. Subsequently the patient underwent VWING insertion rather than venous transposition for constant site dialysis. Although he has required frequent transcatheter dilation of the LIJ-RIJ anastomosis, the patient was successfully dialyzed using this fistula for 5 years. The patient received a cadaveric renal transplant at 5 years 20 days.

CONCLUSIONS

In cases of left innominate vein stenosis, transposing the LIJ can create a new left innominate vein that can alleviate venous hypertension and preserve fistula function. This procedure avoids sternotomy and only requires one anastomosis.

Challenges of Vascular Access in the Pediatric Population

The incidence and prevalence of renal replacement therapy has continued to increase in the pediatric population. Recent data have shown that hemodialysis was the most frequently used dialysis modality, especially in pediatric ESRD patients (age 0-21 years). A well-functioning vascular access is required for effective hemodialysis and choosing the best vascular access option for pediatric patients can be difficult. Pediatric vascular options include arteriovenous fistula, arteriovenous graft, and central venous catheters (CVCs). There is a national initiative for fistula first-catheter last approach; however, CVCs have been reported as the most conventionally utilized vascular access option in pediatric patients. The use of CVCs should be minimized or avoided as they are associated with high risk of infections, thrombosis, and other complications. Thus, it is important for practitioners to plan appropriately in advance, practice good clinical judgment, and assure that the best vascular access is placed according to the patient's needs. Therefore, this article reviews the different types of pediatric vascular access and the associated benefits and potential complications of each.

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.

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.

Vascular Access Choice, Complications, and Outcomes in Children on Maintenance Hemodialysis: Findings From the International Pediatric Hemodialysis Network (IPHN) Registry

RATIONALE & OBJECTIVE

Arteriovenous fistulas (AVFs) have been recommended as the preferred vascular access for pediatric patients on maintenance hemodialysis (HD), but data comparing AVFs with other access types are scant. We studied vascular access choice, placement, complications, and outcomes in children.

STUDY DESIGN

Prospective observational cohort study.

SETTING & PARTICIPANTS

552 children and adolescents from 27 countries on maintenance HD followed up prospectively by the International Pediatric HD Network (IPHN) Registry between 2012 and 2017.

PREDICTOR

Type of vascular access: AVF, central venous catheter (CVC), or arteriovenous graft.

OUTCOME

Infectious and noninfectious vascular access complication rates, dialysis performance, biochemical and hematologic parameters, and clinical outcomes.

ANALYTICAL APPROACH

Univariate and multivariable linear mixed models, generalized linear mixed models, and proportional hazards models; cumulative incidence functions.

RESULTS

During 314 cumulative patient-years, 628 CVCs, 225 AVFs, and 17 arteriovenous grafts were placed. One-third of the children with an AVF required a temporary CVC until fistula maturation. Vascular access choice was associated with age and expectations for early transplantation. There was a 3-fold higher living related transplantation rate and lower median time to transplantation of 14 (IQR, 6-23) versus 20 (IQR, 14-36) months with CVCs compared with AVFs. Higher blood flow rates and Kt/V_urea were achieved with AVFs than with CVCs. Infectious complications were reported only with CVCs (1.3/1,000 catheter-days) and required vascular access replacement in 47%. CVC dysfunction rates were 2.5/1,000 catheter-days compared to 1.2/1,000 fistula-days. CVCs required 82% more revisions and almost 3-fold more vascular access replacements to a different site than AVFs (P<0.001).

LIMITATIONS

Clinical rather than population-based data.

CONCLUSIONS

CVCs are the predominant vascular access choice in children receiving HD within the IPHN. Age-related anatomical limitations and expected early living related transplantation were associated with CVC use. CVCs were associated with poorer dialysis efficacy, higher complication rates, and more frequent need for vascular access replacement. Such findings call for a re-evaluation of pediatric CVC use and practices.

A propensity-matched comparison of hard outcomes in children on chronic dialysis

Data concerning outcomes of children on hemodialysis (HD) and peritoneal dialysis (PD) are scarce and frequently derived from single-center experiences. We sought to compare survival and transplantation rates in a large cohort of PD and HD patients. We extracted all patients initiating dialysis under 16 years of age between 2004 and 2013 from the Italian Registry of Pediatric Chronic Dialysis. Patients on PD were propensity-matched to those on HD based on gender, age, primary cause of ESRD, and the number of co-morbidities. Stratified Cox proportional hazard models were used to compare outcomes by dialysis modality. Three hundred ten patients were matched from 452 incident patients. In the unmatched cohort, PD patients were younger, more likely to be diagnosed with CAKUT, and had a higher urine output than HD patients. In the propensity-matched cohort, covariates were balanced between the two groups. At 2 years, the cumulative hazard ratio for death was similar (CHR 0.95, 95% CI 0.17-5.20) for HD relative to PD patients; and at 5 years, the CHR was lower for HD patients (0.22 95% CI 0.16-0.29). The cumulative incidence of transplantation at 3 years after dialysis initiation was 60.9% in HD patients and 59.7% in PD patients, with a CHR of 1.03 (95% CI 0.73-1.45).

CONCLUSIONS

Pediatric PD and HD patients have distinct characteristics. After controlling for treatment-selection biases, children selected to start on PD or HD exhibit a similar mortality risk during the first 2 years on treatment, after which this risk increases in PD children. What is Known: • Few studies have compared hard outcomes in children on maintenance dialysis. • Children started on different dialysis modalities have distinct characteristics that impact on survival. What is New: • After controlling for treatment-selection biases, children selected to start dialysis on PD or HD exhibit a similar mortality risk during the first 2 years on treatment, after which this risk appears to be increased in PD children. • An "integrative care" approach should be used in children on PD, switching them to HD when PD-related morbidity tends to increase.

Microsurgery for "wrist" arteriovenous fistula creation in children: a retrospective cohort study

INTRODUCTION

Creating functional arteriovenous fistulae (AVF) at the wrist is challenging in paediatric patients because of the small calibre of the blood vessels.

METHODS

We report our experience with AVF surgery in children younger than 15 years of age using microsurgical techniques. Twenty-five patients underwent AVF surgery between 2003 and 2015 (20 for haemodialysis, 4 for plasmapheresis and 1 for parenteral nutrition). Median (range) age was 9 (2-15) years and median weight was 24 (8-61) kg.

RESULTS

The one-month occlusion rate was 8%. The primary and secondary patency rates at 1, 2, 3 years were: 60%, 49%, 42%, and 82%, 72%, 54%, respectively. The median (range) maturation time was 4.53 (0.5-11.2) months. We found no statistically significant effect of patient age, body weight, type of AVF and indication for AVF creation on the primary and secondary patency rates.

CONCLUSIONS

Microsurgical AVF creation at the wrist can be performed with satisfactory results and should be the preferred technique in the paediatric population.

Dialysis in Children and Adolescents: The Pediatric Nephrology Perspective

The care of children with end-stage renal disease (ESRD) is highly specialized and often poorly understood by nonpediatric providers and facility/institution administrators. As such, this position paper has been created to offer provider, facility, and institutional guidance regarding the components of care necessary for children receiving dialysis. Key differences between adult and pediatric dialysis units are highlighted. Responsibilities and expectations of the members of the interdisciplinary dialysis team are outlined as they pertain specifically to the care of pediatric dialysis patients. Physical and staffing requirements of the dialysis facility are reviewed, again focusing on unique needs and challenges faced by the pediatric dialysis care team. Among these, vascular access options and proper planning of ESRD care are underscored. Pediatric quality-of-life metrics differ significantly from adult quality variables, and proper tools for assessment must be used. Endorsed by the Council of the American Society of Pediatric Nephrology (ASPN), this position paper serves as a reference tool for the provision of care to pediatric patients with ESRD.

Timing of first arteriovenous fistula cannulation in children on hemodialysis

BACKGROUND

Due to lower complication rates in comparison to central venous catheter (CVC) arteriovenous fistulas (AVFs) are now the preferred hemodialysis access. Recommendations for the first access cannulation range from 6 to 12 weeks, which could lead to temporary or even permanent preference for CVC while awaiting the maturation of the newly created AVF. The aim of this study was to evaluate the influence of first cannulation of AVFs on primary (PP) and secondary (SP) patency rates in children on hemodialysis (HD).

METHODS

This was a retrospective cohort study of 42 pediatric patients with a median age of 14 (range 7-17) years. At the time of surgical AVF creation 21 patients (end-stage renal disease) were still on HD via CVC or peritoneal catheter, while 21 were pre-emptive with initiation of HD expected within a few weeks. All patients received an AVF by the same experienced surgeon between February 1993 and May 2014. Primary failure (PF) was defined as the inability to use the AVF even once due to absent maturation or occlusion within 4 weeks after creation. PP was defined as the interval from time of access placement to any intervention designed to maintain or reestablish patency, to access thrombosis or the time of measurement of patency, while SP was defined as the total lifespan from creation to access abandonment, end of follow-up or loss.

RESULTS

Primary failure was observed in six (14.3 %) of 42 AVFs (all radiocephalic fistulas) within the first 10 days after cannulation. Excluding PF, the PP/SP rates at 1, 3, 6, 12, 18 and 24 months were 100/100, 91/99, 86/98, 76/95, 55/85 and 44/77 %, respectively. There was a significant decrease in PP when first cannulation was performed within the first 30 days after creation compared to first cannulation performed after 30 days (p = 0.004). In terms of PP/SP outcome and timing of the first cannulation, there was no significant difference in thee outcome of PP/SP between first cannulation within the first 45 days after creation and that after 45 days (p = 0.091/0.883).

CONCLUSIONS

The findings suggest that cannulation of AVF within 30 days after surgical creation reduces PP, while SP may be influenced less by time until cannulation. We also found no significant differences in PP after maturing periods of >45 days.

Does pre- and post-angioplasty Doppler ultrasound evaluation help in predicting vascular access outcome?

BACKGROUND

Kidney Disease - Improving Global Outcomes (KDIGO) recommends post-percutaneous transluminal angioplasty (PTA) <30% residual stenosis (RS) and hemodynamic parameters improvement. Primary end point: how post-PTA access blood flow (ABF) improvement predicts vascular access (VA) outcome. Secondary: compare Doppler ultrasound (DU) and angiography diagnostic accuracy; determine how other factors predict outcome.

METHODS

Eighty patients. DU evaluation performed pre- and post-PTA. Several parameters recorded. Secondary patency verified after 6 months.

RESULTS

Initial ABF 537 ± 248 mL/min; final ABF 1013 ± 354 mL/min. Number and location of stenosis was highly correlated between DU and angiography (p<0.001); central vessels mismatching. First semester overall survival was 63%; significantly better for fistulas (76%) than grafts (51.7%), p 0.044. Final RS>30% associated to better survival, p 0.038. Initial ABF<500 mL/min and multiple stenosis did not affect outcome (p>0.05). A >2-fold ABF increase had no significant impact on fistulas (p>0.05) but was significantly associated with worst outcomes in grafts (23.1% vs. 73.5%, p 0.009). Grafts had lower survival (HR 3.3, p 0.034).

CONCLUSIONS

Although less accurate for central lesions, DU has a key role on VA surveillance, allowing a morphologic and hemodynamic assessment. Angioplasty is effective in preserving VA; however, it may increase restenosis due to accelerated neointimal hyperplasia. Current parameters are not useful. Trials addressing this issue are needed.

Pediatric patients undergoing arteriovenous fistula surgery without intraoperative heparin

INTRODUCTION

Arteriovenous fistula (AVF) creation in children could be extremely challenging for vascular surgeons due to small vessels with a high tendency of vasospasm. This could be one reason for primary failures (PF) and early access thrombosis. There exists no guideline for the need of intraoperative heparin administration during hemodialysis fistula creation. The aim of this study was to evaluate the effect of intra-operative heparin administration on immediate outcome.

METHODS

Medical records of 42 pediatric patients aged between 7 and 17 years were retrospectively reviewed. All received an AVF under inpatient conditions by exclusively one vascular surgeon with many years of professional experience. The intraoperative anticoagulation standards changed by the years 2001 based on the decision of the vascular surgeon. Therefore, we build two groups (group 1: 14 patients with 5000 IU of intravenous heparin during surgery and group 2: 28 patients without heparin). Major complications included hematoma or bleeding leading to surgery. PF was defined as the inability to use the AVF even once due to absent maturation or occlusion within 4 weeks after creation.

RESULTS

We found 6 (14%) PF with the need of immediate surgical access revision (three from group 1 and three from group 2; p = 0.350). There were no bleedings leading to surgery in all cases, but 5 (12%) hematomas without the need of surgical revision (three from group 1 and two from group 2; p = 0.736).

CONCLUSIONS

We found no benefit of heparin administration during clamping the arteries while performing the arteriovenous fistula in pediatric patients.

Vitamin K antagonists in children with central venous catheter on chronic haemodialysis: a pilot study

BACKGROUND

To date, no study has investigated the use of vitamin K antagonists (VKA) in children undergoing chronic haemodialysis (HD) with a central venous catheter (CVC).

METHODS

Consecutive patients aged <18 years with a newly placed tunnelled CVC for chronic HD were enrolled over a 3-year period. Children with active nephrotic syndrome or a history of venous thrombosis received warfarin (VKA group) with therapeutic target international normalised ratios of between 2.0 and 3.0. Patients at standard risk of CVC malfunction were not treated with VKA (standard group). The primary end-point was overall CVC survival.

RESULTS

The VKA group consisted of nine patients (median age 10.6 years; range 1.2-15.3 years) with 11 CVC, and the standard group comprised eight patients (11.8 years; 6.1-17.3 years) with ten CVC. The 6- and 12-month CVC survival was significantly longer in the VKA group than in the standard group (100 vs. 60 % and 83.3 vs. 16.7 %, respectively; p < 0.05), with a median survival of 369 and 195 days, respectively (p < 0.05). None of the CVC in the VKA group required removal due to malfunction, as compared to four in the standard group. No major bleeding episodes occurred in either group.

CONCLUSIONS

Therapy with VKA would appear to be safe in children on chronic HD and may improve CVC survival in patients at increased risk of CVC thrombosis.

Predictive parameters of arteriovenous fistula functional maturation in a population of patients with end-stage renal disease

INTRODUCTION

With increasing numbers of patients diagnosed with ESRD, arteriovenous fistula (AVF) maturation has become a major factor in improving both dialysis related outcomes and quality of life of those patients. Compared to other types of access it has been established that a functional AVF access is the least likely to be associated with thrombosis, infection, hospital admissions, secondary interventions to maintain patency and death.

AIM

Study of demographic factors implicated in the functional maturation of arteriovenous fistulas. Also, to explore any possible association between preoperative haematological investigations and functional maturation.

METHODS

We performed a retrospective chart review of all patients with ESRD who were referred to the vascular service in the University Hospital of Limerick for creation of vascular access for HD. We included patients with primary AVFs; and excluded those who underwent secondary procedures.

RESULTS

Overall AVF functional maturation rate in our study was 53.7% (52/97). Female gender showed significant association with nonmaturation (P = 0.004) and was the only predictor for non-maturation in a logistic regression model (P = 0.011). Patients who had history of renal transplant (P = 0.036), had relatively lower haemoglobin levels (P = 0.01) and were on calcium channel blockers (P = 0.001) showed better functional maturation rates.

CONCLUSION

Female gender was found to be associated with functional non-maturation, while a history kidney transplant, calcium channel-blocker agents and low haemoglobin levels were all associated with successful functional maturation. In view of the conflicting evidence in the literature, large prospective multi-centre registry-based studies with well-defined outcomes are needed.

Maintenance dialysis in developing countries

Patients with end-stage renal disease require renal replacement therapy with maintenance hemodialysis or chronic peritoneal dialysis while awaiting transplantation. In addition to economic issues and limited state funding for advanced health care, the lack of trained medical personnel contributes to scarce dialysis facilities for children in developing countries. The establishment and operation of a hemodialysis unit with multidisciplinary facilities is both cost- and labor-intensive. Hemodialysis is usually carried out three times a week in a hospital setting and affects the curricular and extracurricular activities of the patient. Chronic ambulatory or cyclic peritoneal dialysis is technically simpler and allows better nutrition and growth, but is expensive for the majority of patients who must pay out of their own pocket. Multiple initiatives to enhance the training of pediatricians and nurses in skills related to initiating and managing patients on maintenance dialysis have resulted in the improved survival of children with end-stage renal disease. Support from state governments and philanthropic institutions have helped in establishing pediatric nephrology units that are equipped to provide renal replacement therapy for children.

Vascular access for chronic hemodialysis in children: arteriovenous fistula or central venous catheter?

BACKGROUND

The choice of vascular access (VA) for hemodialysis (HD) in end-stage renal disease (ESRD) is arteriovenous fistula (AVF) or central venous catheter (CVC). Whereas clinical practice guidelines suggest AVF to preserve the vascular bed, pediatric nephrologists tend to favor CVC for shorter-term dialysis. Our objective was to determine whether pediatric priority allocation policies for deceased-donor kidneys affect VA planning.

METHODS

Pediatric priority for deceased-donor kidneys was instituted in Quebec in 2004. We retrospectively compared clinical practice on AVF, CVC, wait time on transplant list, HD duration in pre-policy (group A) and post-policy (group B) from 1997-2011.

RESULTS

We identified 78 patients with a median age of 14.7 years (range, 0.7-20.5 years) and weight of 46 kg (12.5-95 kg); AVF decreased from 76 % in group A to 41 % in group B (p = 0.002). Wait times on transplant list were significantly reduced: median 413.5 days (range, 2-1,910 days) in group A vs. 89 days (range, 18-692 days) in group B (p = 0.003). Time on HD for deceased-donor recipients was shorter: 705 (range, 51-1,965 days) group A vs. 349.5 days (range, 158-1,060 days) group B (p = 0.01).

CONCLUSIONS

This is the first study to document VA changes related to pediatric priority allocation policy. Our fistula-first center saw a shift toward CVC-first.

Outcome of tunnelled central venous catheters used for haemodialysis in children weighing less than 15 kg

PURPOSE

Central venous catheters (CVC) are frequently used for haemodialysis (HD) in children. However, there is paucity of information on the outcomes of CVCs when used for HD in very young patients. Our objective is to report the success, safety and complication rates of CVCs used for HD in children weighing less than 15 kg.

MATERIALS AND METHODS

This is a single-center retrospective study of all patients with end-stage renal disease (ESRD) weighing <15kg, who underwent a tunneled CVC placement for HD, between July 2006 and June 2012 at our institution. Analysed data included clinical background, age and weight at initiation of HD, outcome of HD, CVC vein insertion site, reason for removal, and catheter survival (in days).

RESULTS

Thirty-one CVC were placed in 11 patients weighing <15 kg, 8 males and 3 females. The main causes of ESRD were renal dysplasia and congenital nephrotic syndrome. At the beginning of HD, mean age was 27.5 (range 5-60) months and mean weight was 10.4 kg (4.5-13 kg). The preferred insertion site was the right internal jugular vein (90%). Mean duration of HD was 312 days. Mechanical factors were the main reason for catheter removal (39%). Mean catheter survival was 110 days/catheter.

CONCLUSIONS

We believe our study provides relevant information and encouraging data to support the use of CVC for HD in this cohort of infants; however, further improvement in prevention of catheter thrombosis and management of infections needs to be achieved.

Hemodialysis for infants, children, and adolescents

Children with chronic kidney disease stage 5 requiring dialysis can be treated by peritoneal or hemodialysis. In the United Kingdom nearly twice as many children receive peritoneal dialysis compared with hemodialysis. Technical aspects of pediatric hemodialysis are challenging and include the relative size of extracorporeal circuit and child's blood volume, assessment of adequacy,technical and complications of vascular access. Alternatives to standard hospital-based hemodialysis are also increasingly available. Optimizing nutritional status with the support of specialist pediatric dietitians is key to the management of children receiving hemodialysis. The effects of chronic illness on growth and school achievement, as well as the psychological, emotional, and social development of the child should not be underestimated. This review focuses on the above elements and highlights common pediatric practice in the United Kingdom.

Outcomes with arteriovenous fistulas in a pediatric population

OBJECTIVE

Kidney Disease Outcome Quality Initiative guidelines recommend permanent access in dialysis patients aged 0 to 19 years who weigh >20 kg and are unlikely to receive a transplant within 1 year. Unfortunately, >80% of these patients currently receive dialysis through a permanent catheter and are exposed to the associated risks and shortcomings. With a clear imperative to increase the incident use of permanent access in pediatric patients, our objective was to examine the long-term outcomes of pediatric arteriovenous fistulas (AVFs).

METHODS

A retrospective review was performed of all AVFs created in a hemodialysis (HD) population aged 0 to 19 years at a single institution from 1999 to 2012. Data abstracted included age, weight, etiology of renal failure, time on dialysis, central venous catheter history, and transplantation history. Data were analyzed to determine the influence of these variables on primary and secondary patency.

RESULTS

During the study period, 101 AVFs were performed in 93 patients, of whom 65 patients (70%) were male. Mean patient age was 14 years (range, 3-19 years), and mean weight was 51 kg (range, 12-131 kg). At the time of AVF creation, 66 patients (82%) were already receiving HD, with a mean length of HD dependence of 18 months. At the time of surgery, 78% of patients had a previous central venous catheter, and 24% had two or more catheters. Procedures performed included 43 radiocephalic fistulas, 29 brachiocephalic fistulas, 20 basilic vein transpositions, and 9 femoral vein transpositions. Mean follow-up was 2.5 years. The 2-year and 4-year primary and secondary patency rates were 83% and 92%, and 65% and 83%, respectively. Increasing age was correlated with improved primary patency (P = .02) but had no effect on secondary patency. Weight, etiology, catheter location, and catheter history were not significantly associated with primary or secondary patency. During the postoperative period, 68 patients (75%) received a renal transplant, with a mean time to transplant of 556 days.

CONCLUSIONS

AVFs demonstrate excellent long-term patency with minimal complications in pediatric HD patients, regardless of weight. Concerted efforts should be made to improve the incident use of AVFs in all pediatric patients with end-stage renal disease.

A comparison of arteriovenous fistulas and central venous lines for long-term chronic haemodialysis

BACKGROUND

Despite the Fistula First initiative there is still reluctance to use arteriovenous fistulas (AVF) for chronic haemodialysis (HD) in children. Our aim was to compare outcomes of AVFs and central venous lines (CVL) in children on chronic HD in a centre where AVF is the primary choice for vascular access.

PATIENTS AND METHODS

This was a retrospective case notes analysis of access complications, dialysis adequacy and laboratory outcomes in children who underwent dialysis for at least a year by AVF (n = 20, median age 14.2 years, range (2.9-16.5) and CVL (n = 5, median age 2.4 years, range 2.0-12.2) between January 2007 and December 2010.

RESULTS

Primary access failure rate (patient-months) was 1 per 78.8 for AVF (n = 5) and 1 per 15.5 for CVLs (n = 7, p = 0.3). Failure thereafter was 1 per 131.3 and 1 per 18.5 for AVF and CVLs respectively (n = 3 and 6 respectively; p = 0.2). The annualised hospitalisation rate for access malfunction was 0.44% and 3.1% for AVFs and CVLs respectively (p = 0.004). Patients with AVFs had a lower infection rate of 0.25 per 100 patient-months compared with CVL at 3.2 per 100 (p = 0.002). There was no difference in dialysis adequacy or laboratory values between AVF and CVL groups. Access survival rates (including both primary and secondary access failure) were significantly higher for AVF compared with CVL (p = 0.0002, hazard ratio = 0.15, 95% confidence interval 0.04-0.37).

CONCLUSIONS

Patients with AVF spend less time in hospital than those dialysed by CVLs and have a much lower access infection rate. These findings emphasise the need to use AVF as first-line access for paediatric patients on chronic HD.

Vascular access: choice and complications in European paediatric haemodialysis units

BACKGROUND

European and U.S. guidelines emphasise that permanent vascular access in the form of arteriovenous fistulae (AVF) or grafts (AVG) are preferable to central venous catheters (CVC) in paediatric patients on long-term haemodialysis. We report vascular access choice and complication rates in 13 European paediatric nephrology units.

METHODS

A survey of units participating in the European Pediatric Dialysis Working Group requesting data on type of vascular access, routine care and complications in patients on chronic haemodialysis between March 2010 and February 2011.

RESULTS

Information was complied on 111 patients in 13 participating centres with a median age of 14 (range 0.25-20.2) years. Central venous catheters were used in 67 of 111 (60%) patients, with 42 patients (38%) having an AVF and two patients (2%) having an AVG. Choice of vascular access was significantly related to patient age, with patients with AVF/AVG having a median age of 16 years compared to 12 years for patients with CVCs (p < 0.001). Routine CVC exit site care and catheter lock solution use differed between centres. CVC infections requiring intravenous antibiotics were reported at a rate of 1.9 and exit site infections at a rate of 1.8 episodes/1000 catheter days. Overall infective complications necessitating CVC change occurred at a rate of 0.9 episodes/1000 catheter days. No infective complications were reported in patients with AVF/AVG access. The rate of CVC infections requiring intravenous antibiotics was significantly lower in patients in whom CVC exit sites were cleaned weekly as opposed to every dialysis session (relative risk with every session cleaning vs. weekly cleaning 2.58, 95% confidence interval 1.17-5.69). Catheter malfunction (inadequate blood flow) was a more prevalent complication necessitating 22.4 thrombolytic interventions/1000 catheter days and 2.1 CVC changes/1000 catheter days.

CONCLUSIONS

Central venous catheters remain the predominant choice of vascular access in Europe despite problems of malfunction and infection. AVF/AVG were predominantly used in adolescents without reported complications. More regular exit site cleaning may predispose to CVC infection, but this observation requires prospective evaluation.

Antithrombotic therapy in neonates and children: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines

BACKGROUND

Neonates and children differ from adults in physiology, pharmacologic responses to drugs, epidemiology, and long-term consequences of thrombosis. This guideline addresses optimal strategies for the management of thrombosis in neonates and children.

METHODS

The methods of this guideline follow those described in the Methodology for the Development of Antithrombotic Therapy and Prevention of Thrombosis Guidelines: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines.

RESULTS

We suggest that where possible, pediatric hematologists with experience in thromboembolism manage pediatric patients with thromboembolism (Grade 2C). When this is not possible, we suggest a combination of a neonatologist/pediatrician and adult hematologist supported by consultation with an experienced pediatric hematologist (Grade 2C). We suggest that therapeutic unfractionated heparin in children is titrated to achieve a target anti-Xa range of 0.35 to 0.7 units/mL or an activated partial thromboplastin time range that correlates to this anti-Xa range or to a protamine titration range of 0.2 to 0.4 units/mL (Grade 2C). For neonates and children receiving either daily or bid therapeutic low-molecular-weight heparin, we suggest that the drug be monitored to a target range of 0.5 to 1.0 units/mL in a sample taken 4 to 6 h after subcutaneous injection or, alternatively, 0.5 to 0.8 units/mL in a sample taken 2 to 6 h after subcutaneous injection (Grade 2C).

CONCLUSIONS

The evidence supporting most recommendations for antithrombotic therapy in neonates and children remains weak. Studies addressing appropriate drug target ranges and monitoring requirements are urgently required in addition to site- and clinical situation-specific thrombosis management strategies.

Permanent vascular access survival in children on long-term chronic hemodialysis

The aim of this study is to report a single-center experience regarding the management and outcome of permanent vascular accesses (VA) in children on chronic hemodialysis (HD). We analyzed the survival of permanent VA in 79 pediatric patients with end-stage renal disease patients on chronic HD between January 2000 and December 2008. One hundred and thirty-seven VA [89 native fistulas (AVFs) and 48 grafts (AVGs)] were created in 79 children. The creation of AVFs was significantly more frequent in children weighing >25 kg and AVGs in children weighing <25 kg (p = 0.003). The 1-year primary patency rate was 50% for AVF and 30% for AVG. The secondary patency rates at 1, 2, and 3 years for AVFs were 73, 50, and 20% and for AVGs were 64, 36, and 20%, respectively. The total number of surgical and endovascular interventions was significantly higher in AVGs (p <or=0.05). Access stenosis, thrombosis and infection episodes occurred more frequently in AVG (p = 0.02). VAs had a high rate of interventions. Our study demonstrated better results of AVFs formation over AVGs, for long-term HD access in pediatrics. Surveillance and radiologic procedures are necessary for early detection and treatment of access complications in order to extend access survival.