Permanent hemodialysis vascular access survival in children and adolescents with end-stage renal disease

Establishing an autogenous vascular access program in a Guatemalan comprehensive pediatric nephrology center

BACKGROUND

The Guatemalan Foundation for Children with Kidney Diseases collaborated with Bridge of Life, a not-for-profit charitable organization, to establish a vascular access program. We reviewed our experience with graded surgical responsibility and structured didactic training, creating arteriovenous fistulas (AVF) for Guatemalan children.

METHODS

Pediatric vascular access missions were completed from 2015 to 2023 and analyzed retrospectively. Follow-up was completed by the Guatemalan pediatric surgeons, nephrologists, and nursing staff. AVF patency and patient survival were evaluated by Kaplan-Meier life-table analysis with univariate and multivariable association between patient demographic variables by Cox proportional hazards models.

RESULTS

Among a total of 153 vascular access operations, there were 139 new patient procedures, forming the study group for this review. The mean age was 13.6 years, 42.6% were female, and the mean BMI was 17.3. Radial or ulnar artery-based direct AVFs were established in 100 patients (71.9%) and ten of the 25 transposition procedures. Brachial artery inflow was required in 29 direct AVFs (20.9%). Two patients underwent femoral vein transpositions. Access-related distal ischemia was not encountered. Seven of the AVF patients later required access banding for arm edema; all had previous dialysis catheters (mean = 9, range 4-12). Primary and cumulative patency rates were 84% and 86% at 12 months and 64% and 81% at 24 months, respectively. The median follow-up was 12 months. Overall patient survival was 84% and 67% at 12 and 24 months, respectively. There were no deaths related to AVF access.

CONCLUSIONS

Safe and functional AVFs were established in a teaching environment within a Guatemalan comprehensive pediatric nephrology center.

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.

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.

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.

Chronic Kidney Disease in Children

Chronic kidney disease (CKD) in children occurs mostly due to congenital anomalies of kidney and urinary tract and hereditary diseases. For advanced cases, a multidisciplinary team is needed to manage nutritional requirements and complications such as hypertension, hyperphosphatemia, proteinuria, and anemia. Neurocognitive assessment and psychosocial support are essential. Maintenance dialysis in children with end-stage renal failure has become the standard of care in many parts of the world. Children younger than 12 years have 95% survival after 3 years of dialysis initiation, whereas the survival rate for children aged 4 years or younger is about 82% at one year."

Demography and Outcomes of Arteriovenous Fistula: Challenges and Future Directions

The incidence and prevalence rates of treated end-stage kidney disease (ESKD) patients are on the rise worldwide. Hemodialysis remains the main modality of providing renal replacement therapy for the ESKD patients, and the preferred vascular access is an arteriovenous fistula (AVF). The objective is to assess the patency rates and primary failures of the AVF. All patients who attended the Royal Hospital in Muscat, Oman, from January 2010 to December 2014 for AVF creation were included in this study. Data were extracted from the hospital's electronic medical record system where data are entered prospectively. During the period of study from 2010 to 2014, 465 primary fistulae were created in 427 patients. The mean age of the patient was 58 years. Only 6% needed general anesthesia, while the rest were done under regional or local anesthesia. Fifty-one percent of the patients were diabetic. Preemptive AVF was constructed in only 12% of patients. Most cases (47%) had left brachiocephalic (BC) fistulae. The left radiocephalic (RC) fistulae constituted 25.7% and the left brachiobasilic fistulae 9.9%. The remaining were constructed in the right upper limb. The total patency was achieved in 80% of fistulae and the failure rate was 20% at 6 months. Whereas, at 12 months, the total patency rate was 71% and the failure rate was 29%. Thus, we can conclude that more than 50% of patients, half of them being females, were diabetics. This resulted in more fistulae being constructed in the arm, namely left BC fistulae and left RC fistulae. Furthermore, it is important to note that only a very small percentage of patients had an established preemptive AVF. These factors may be responsible for a failure rate of 20% and 29% of the AVFs at 6 months and 12 months, respectively.

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.

Outcomes of kidney injury including dialysis and kidney transplantation in pediatric oncology and hematopoietic cell transplant patients

Pediatric oncology and hematopoietic cell transplant (HCT) patients are susceptible to both acute kidney injury (AKI) and chronic kidney disease (CKD). The etiologies of AKI vary but include tumor infiltration, radiation, drug-induced toxicity, and fluid and electrolyte abnormalities including tumor lysis syndrome. HCT patients can also have additional complications such as sinusoidal obstructive syndrome, graft-versus-host disease, or thrombotic microangiopathy. For patients with severe AKI requiring dialysis, multiple modalities can be used successfully, although continuous kidney replacement therapy (CKRT) is often the principal modality for critically ill patients. While increasing numbers of pediatric cancer and HCT patients are now surviving long term, they remain at risk for a number of chronic medical conditions, including CKD. Certain high-risk patients, due to underlying risk factors or treatment-related complications, eventually develop kidney failure and may require kidney replacement therapies. Management of co-morbidities and complications associated with kidney failure, including use of erythropoietin for anemia and potential need for ongoing cancer-related treatment while on dialysis, is an additional consideration in this patient population. Kidney transplantation can be successfully performed in pediatric cancer survivors, although additional features such as specific cancer diagnosis and duration of remission should be considered.

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.

Hemodialysis and peritoneal dialysis access related outcomes in the pediatric and adolescent population

BACKGROUND

There is paucity of comparative data on the objective performance of arteriovenous fistulas (AVF), grafts (AVG), hemodialysis (HD) catheter and peritoneal dialysis (PD) catheter in the pediatric population.

METHODS

A retrospective analysis of all patients <21 years in the United States Renal Database System who had an AVF, AVG, HD catheter or PD catheter placed for dialysis access between 1/2007 and 12/2014 was performed. Multivariable cox regression was used to evaluate mortality, patency (primary, primary-assisted and secondary), maturation and catheter survival.

RESULTS

The 11,575 patients studied comprised of 9445 (82%) HD, 1435 (12%) PD, 528 (4.6%) HD to PD and 167 (1.4%) PD to HD patients. The HD subcohort comprised of 1296 (13.7%) AVF initiates, 199 (2.1%) AVG initiates, 1347 (14.3%) AVF converts after initial HD catheter use, 292 (3.1%) AVG converts and 6311 (67%) patients who persistently utilized HD catheters. There was no difference between PD and HD in patients 0-5 (aHR: 1.36; 95% CI: 0.89-2.07; P = 0.15) and 6-12 years (aHR: 1.05; 95% CI: 0.72-1.52; P = 0.8). However, PD was associated with 73% and 76% increase in mortality relative to HD among patients in the 13-17 (aHR: 1.73; 95% CI: 1.35-2.21; P < 0.001) and 18-20 (aHR: 1.76; 95% CI: 1.38-2.24; P < 0.001) age categories. AVG was associated with 78% increase in mortality compared to AVF (aHR: 1.78; 95% CI: 1.41-2.25; P < 0.001). Persistent use of HD catheters was associated with 29% increase in mortality (aHR: 1.29; 95% CI: 1.07-1.57; P = 0.009) compared to initiation and persistent use of AVF. Conversion from HD catheter to AVF was associated with 66% decrease in mortality compared to persistent HD catheter use (aHR: 0.34; 95% CI: 0.28-0.40; P < 0.001). Primary, primary assisted and secondary patency were higher for AVF compared to AVG.

CONCLUSION

There was no difference in risk adjusted mortality between HD and PD in children less than 13 years. PD is associated with higher mortality compared to HD in adolescents. Initiation of HD with AVF is associated with better patency and patient survival relative to AVG and persistent use of HD catheters in pediatric patients irrespective of transplant potential. Conversion from HD catheter to AVF or AVG in patients who inevitably initiate HD with a catheter is associated with better survival compared to persistent HD catheter use.

TYPE OF STUDY

Retrospective cohort study.

LEVEL OF EVIDENCE

Level II.

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.

KDOQI Clinical Practice Guideline for Vascular Access: 2019 Update

The National Kidney Foundation's Kidney Disease Outcomes Quality Initiative (KDOQI) has provided evidence-based guidelines for hemodialysis vascular access since 1996. Since the last update in 2006, there has been a great accumulation of new evidence and sophistication in the guidelines process. The 2019 update to the KDOQI Clinical Practice Guideline for Vascular Access is a comprehensive document intended to assist multidisciplinary practitioners care for chronic kidney disease patients and their vascular access. New topics include the end-stage kidney disease "Life-Plan" and related concepts, guidance on vascular access choice, new targets for arteriovenous access (fistulas and grafts) and central venous catheters, management of specific complications, and renewed approaches to some older topics. Appraisal of the quality of the evidence was independently conducted by using a Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach, and interpretation and application followed the GRADE Evidence to Decision frameworks. As applicable, each guideline statement is accompanied by rationale/background information, a detailed justification, monitoring and evaluation guidance, implementation considerations, special discussions, and recommendations for future research.

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.

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.

Predictors of patency for arteriovenous fistulae and grafts in pediatric hemodialysis patients

BACKGROUND

Hemodialysis (HD) guidelines recommend permanent vascular access (PVA) in children unlikely to receive kidney transplant within 1 year of starting HD. We aimed to determine predictors of primary and secondary patency of PVA in pediatric HD patients.

METHODS

Retrospective chart reviews were performed for first PVAs in 20 participating centers. Variables collected included patient demographics, complications, interventions, and final outcome.

RESULTS

There were 103 arterio-venous fistulae (AVF) and 14 AV grafts (AVG). AVF demonstrated superior primary (p = 0.0391) and secondary patency (p = 0.0227) compared to AVG. Primary failure occurred in 16 PVA (13.6%) and secondary failure in 14 PVA (12.2%). AVF were more likely to have primary failure (odds ratio (OR) = 2.10) and AVG had more secondary failure (OR = 3.33). No demographic, clinical, or laboratory variable predicted primary failure of PVA. Anatomical location of PVA was predictive of secondary failure, with radial having the lowest risk compared to brachial (OR = 12.425) or femoral PVA (OR = 118.618). Intervention-free survival was predictive of secondary patency for all PVA (p = 0.0252) and directly correlated with overall survival of AVF (p = 0.0197) but not AVG. Study center demonstrated statistically significant effect only on intervention-free AVF survival (p = 0.0082), but not number of complications or interventions, or outcomes.

CONCLUSIONS

In this multi-center pediatric HD cohort, AVF demonstrated primary and secondary patency advantages over AVG. Radial PVA was least likely to develop secondary failure. Intervention-free survival was the only predictor of secondary patency for AVF and directly correlated with overall access survival. The study center effect on intervention-free survival of AVF deserves further investigation.

Autologous arteriovenous fistulas for hemodialysis using microsurgery techniques in children weighing less than 20 kg

BACKGROUND

This study aimed to describe the efficiency and longevity of arteriovenous fistula (AVF) for hemodialysis (HD) in children weighing ≤20 kg.

METHODS

We collected data of all AVFs created using microsurgery techniques between 1988 and 2015. Success was considered as the ability to use the AVF for HD. Primary and secondary patency rates were measured.

RESULTS

Forty-eight AVFs (35 forearm, 13 upper arm) were created in 41 children with a median weight of 13.5 kg (range 5.5-20). The need for a second AVF was significantly higher in younger and thinner children at the time of AVF creation (p = 0.046 and p = 0.019, respectively). Successful use for HD occurred in 42 AVFs (87.5%), while six (12.5%) resulted in failure for early thrombosis or nonmaturation. Median time to first cannulation was 18.8 weeks (range 2-166.3). Primary and secondary patency rates at 1, 5, and 10-year follow-ups were 54.2%, 29.2%, and 13.7%; and 85.4%, 57.7%, and 33%, respectively. Almost one third of thromboses after first AVF cannulation were observed at kidney transplantation (KT) perioperatively. At the end of the follow-up (median duration 5.07 years, range 0-17.95), one patient was still on HD via AVF, two died of unrelated reason, and 38 were transplanted-one of whom returned to HD with a new AVF.

CONCLUSIONS

AVF using microsurgery techniques is feasible in young children, showing an early failure rate of 12.5%. Time to first cannulation may be rather long, but secondary patency is excellent. Thrombosis rate is high during KT.

Primary Thromboprophylaxis with Heparins for Arteriovenous Fistula Failure in Pediatric Patients

Background

To reduce the incidence of early arteriovenous fistula failure (AVF) due to thrombosis in pediatric hemodialysis (HD) patients, a primary thromboprophylaxis (PTP) protocol was initiated at author's institution in June 2005. The goal of this study is to report author's experience with this protocol one year later.

Methods and Results

19 AVFs (14 patients, Historical group) and 8 AVFs (7 patients, PTP group) were created prior to and after initiation of PTP respectively. PTP consisted of unfractionated heparin (5–10 units/kg/hr) infusion postoperatively, followed by subcutaneous low molecular weigh heparin (LMWH) until AVF was matured. LMWH dosing was “Prophylactic” (0.5 mg/kg/d, anti-factor Xa levels: peak 0.25–0.5 and trough < 0.3 units/mL) and “Therapeutic” (1 mg/kg/d, anti-factor Xa level: peak 0.5-1 and trough < 0.5 units/mL) based on thrombosis predisposition. In Historical group, 12 AVFs did not receive thromboprophylaxis (No-treatment group), 5 received 81 mg aspirin/day (Aspirin group), and 2 received LMWH. In No-treatment group 10/12 AVFs failed: 9 thromboses and 1 stenosis. In Aspirin group 1/5 AVFs failed due to thrombosis. In PTP group 1/8 AVFs failed due to stenosis; the first 2 AVFs developed hematoma prompting a reduction in LMWH dose and monitoring trough anti-factor Xa levels, one AVF required thrombectomy after LMWH was transiently held. The incidence of thrombosis was less in PTP group (12.5%) when comparing to No-treatment group (83%) (p < 0.05).

Conclusion

PTP is a feasible option to prevent early thrombosis at AVF. Close clinical and laboratory monitoring including trough anti-factor Xa levels is required to adjust optimum anticoagulation. Larger studies are needed to clarify safety and efficacy of our PTP protocol.

Censoring-robust estimation in observational survival studies: Assessing the relative effectiveness of vascular access type on patency among end-stage renal disease patients

The proportional hazards model is commonly used in observational studies to estimate and test a predefined measure of association between a variable of interest and the time to some event T. For example, it has been used to investigate the effect of vascular access type in patency among end-stage renal disease patients (Gibson et al., J Vasc Surg 34:694-700, 2001). The measure of association comes in the form of an adjusted hazard ratio as additional covariates are often included in the model to adjust for potential confounding. Despite its flexibility, the model comes with a rather strong assumption that is often not met in practice: a time-invariant effect of the covariates on the hazard function for T. When the proportional hazards assumption is violated, it is well known in the literature that the maximum partial likelihood estimator is consistent for a parameter that is dependent on the observed censoring distribution, leading to a quantity that is difficult to interpret and replicate as censoring is usually not of scientific concern and generally varies from study to study. Solutions have been proposed to remove the censoring dependence in the two-sample setting, but none has addressed the setting of multiple, possibly continuous, covariates. We propose a survival tree approach that identifies group-specific censoring based on adjustment covariates in the primary survival model that fits naturally into the theory developed for the two-sample case. With this methodology, we propose to draw inference on a predefined marginal adjusted hazard ratio that is valid and independent of censoring regardless of whether model assumptions hold.

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.

Outcomes of Arteriovenous Fistula for Hemodialysis in Pediatric and Adolescent Patients

Purpose:

This retrospective review aimed to report the outcomes of arteriovenous fistula (AVF) and to evaluate the suitability of AVF as a permanent vascular access in pediatric populations.

Materials and Methods:

Data were collected for all patients aged 0 to 19 years who underwent AVF creation for hemodialysis between January 2000 and June 2014.

Results:

Fifty-two AVFs were created in 47 patients. Mean age was 15.7±3.2 years and mean body weight was 46.7±15.4 kg. Of the 52 AVFs, 43 were radiocephalic AVFs, 7 were brachiocephalic AVFs and 2 were basilic vein transpositions. With a mean follow-up of 49.7±39.2 months, primary patency was 60.5%, 51.4%, and 47.7% at 1, 3, and 5 years, respectively and secondary patency was 82.7%, 79.2% and 79.2% at 1, 3, and 5 years, respectively. Age, body weight, AVF type, the presence of a central venous catheter, use of anticoagulation therapy, and history of vascular access failure were not significantly associated with patency rates. There were 9 cases (17.3%) of primary failure; low body weight was an independent predictor. Excluding cases of primary failure, the mean duration of maturation was 10.0±3.7 weeks. During follow-up, 20 patients (42.6%) underwent kidney transplantation, with a median interval to transplantation of 36 months.

Conclusion:

AVF creation in children and adolescents is associated with acceptable long-term durability, primary failure rate and maturation time. Considering the waiting time and limited kidney graft survival, placement of AVFs should be considered primarily even in patients expected to receive transplantation.

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.

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

BACKGROUND

Arteriovenous fistula (AVF) formation for long-term haemodialysis in children is a niche discipline with little data for guidance. We developed a dedicated Vascular Access Clinic that is run jointly by a transplant surgeon, paediatric nephrologist, dialysis nurse and a clinical vascular scientist specialised in vascular sonography for the assessment and surveillance of AVFs. We report the experience and 2-year outcomes of this clinic.

METHODS

Twelve new AVFs were formed and 11 existing AVFs were followed up for 2 years. All children were assessed by clinical and ultrasound examination.

RESULTS

During the study period 12 brachiocephalic, nine basilic vein transpositions and two radiocephalic AVFs were followed up. The median age (interquartile range) and weight of those children undergoing new AVF creation were 9.4 (interquartile 3-17) years and 26.9 (14-67) kg, respectively. Pre-operative ultrasound vascular mapping showed maximum median vein and artery diameters of 3.0 (2-5) and 2.7 (2.0-5.3) mm, respectively. Maturation scans 6 weeks after AVF formation showed a median flow of 1277 (432-2880) ml/min. Primary maturation rate was 83 % (10/12). Assisted maturation was 100 %, with two patients requiring a single angioplasty. For the 11 children with an existing AVF the maximum median vein diameter was 14.0 (8.0-26.0) mm, and the median flow rate was 1781 (800-2971) ml/min at a median of 153 weeks after AVF formation. Twenty-two AVFs were used successfully for dialysis, a median kt/V of 1.97 (1.8-2.9), and urea reduction ratio of 80.7 % (79.3-86 %) was observed. One child was transplanted before the AVF was used.

CONCLUSIONS

A multidisciplinary vascular clinic incorporating ultrasound assessment is key to maintaining young children on chronic haemodialysis via an AVF.

AV Fistula Creation in Paediatric Patients: Outcome is Independent of Demographics and Fistula Type Reducing Usage of Venous Catheters

Purpose

Even though early transplantation is still the first-line therapy in paediatric patients with end-stage renal disease (ESRD), up to 30% of these patients still require haemodialysis (HD). Creating an arteriovenous fistula (AVF) is quite challenging, particularly in children, leading to disproportional use of catheters. In this paper, we describe our experience in the creation of AVF with currently no in-dwelling catheters in children and adolescents on HD.

Methods

From January 2009 to December 2013, there were 34 patients rated as unfit for transplantation for at least the next 6 months or who had already been on HD through a central venous catheter (CVC). Three patients aged between 12 months and 3 years and weighing 9-12 kg were not suitable for AVF. Finally 31 patients, from 6 to 19 years of age with a mean weight of 43.3 ± 14.5 kg (19-80 kg), were assigned to the alternative of AVF.

Results

During the above-mentioned time period, 31 patients were provided with 32 AVFs; 26 received a distal radiocephalic fistula, five a Gracz-type fistula and one a brachio-basilic fistula. All but two fistulae matured primarily, within an average time of 45 (range: 16-191) days until the first dialysis. The fistula's 1-year primary and primary assisted patency rates were 78% and 94%, respectively.

Conclusions

The creation of a native vascular access is an effective and durable procedure in paediatric and adolescent patients. It reduces using of CVCs and is appropriate both for long-term treatment and as a bridging procedure until renal transplantation.

Healthcare burden of venous thromboembolism in childhood chronic renal diseases

BACKGROUND

Chronic renal diseases (CRD) are associated with approximately 5% of pediatric venous thromboembolism (VTE) cases, but the epidemiology of VTE in CRD is ill-defined.

METHODS

Children (<18 years) with CRD were identified from MarketScan® Research databases. The VTE status of subjects with CRD who qualified for this study was ascertained during the 6 months following the initial diagnosis of CRD. Demographics, healthcare utilization, mortality, and co-morbid conditions were assessed.

RESULTS

A total of 22,877 children with predefined CRD ICD-9-CM codes were identified between April 1, 2003 and June 30, 2012, among whom 0.55% had VTE. Our analysis revealed that in-hospital mortality was more likely in children with VTE than in those without VTE (11.9 vs. 0.9%, respectively; p < 0.0001). The usage of healthcare facilities, based on the number of inpatient admissions, length of stay, outpatient visits, and pharmaceutical claims, was also significantly higher in patients with VTE than in those without (p < 0.0001). Total mean healthcare expenditures for the 6-month follow-up period were 13-fold greater in the VTE group than in the group without VTE ($338,338 ± $544,045 vs. $25,171 ± $90,792; p < 0.0001). In a multivariate model, infection, hemodialysis, and trauma/surgery significantly increased the likelihood of VTE.

CONCLUSIONS

Venous thromboembolism is rare in children with CRD, but it is associated with higher mortality and healthcare utilization when present. Among the children with CRD enrolled in our study, the likelihood of VTE was increased among those with co-morbid, non-renal chronic conditions.

Arteriovenous Access Monitoring with Ultrasound Dilution in a Pediatric Hemodialysis Unit

Background: Permanent arteriovenous (AV) access is the preferred access for dialysis delivery in children and adolescents requiring chronic hemodialysis (HD). Ultrasound dilution (UD) monitoring of AV access flow is widely used in adult HD units for the early detection of stenosis but experience in pediatrics is limited. Methods: We monitored all maintenance HD patients with AV access using a noninvasive screening algorithm based on UD access flow. We assessed the effectiveness of this algorithm by comparing it to fistulagrams and its impact on AV access-related morbidity. Results: AV access thrombosis rates fell from 13.5 per 100 patient-months on HD during the baseline period to 3.5 per 100 patient-months on HD during the screening period (p < 0.04). The mean blood flow rate by UD measurement was lower in AV accesses that went on to thrombose compared to those without thrombosis (1,203 ml/min/1.73 m2 vs. 1,683 ml/min/1.73 m2, p < 0.001). When compared to fistulagrams, the screening algorithm was 94% sensitive and 77% specific in detecting hemodynamically significant stenosis, with positive and negative predictive values of 83 and 91% respectively. Conclusions: A noninvasive UD screening algorithm of AV access flow is very sensitive in detecting hemodynamically significant stenosis and can decrease AV access thrombosis rates.

Reducing central venous catheters in chronic hemodialysis--a commitment to arteriovenous fistula creation in children

BACKGROUND

An internal permanent vascular access [arteriovenous fistula (AVF) or arteriovenous graft (AVG)] is preferred over central venous catheters (CVC) for chronic hemodialysis. However, CVC remain the most commonly used access in children. The objective of this study was to evaluate our experience with AVF.

METHODS

We conducted a retrospective chart review of children aged 1-18 years on chronic hemodialysis from 2001 to 2012. Patients were divided into three time periods: 2001-2005, 2006-2009 and 2010-2012. A systematic approach to AVF placement was introduced in our department in 2006 which resulted in a greater number of AVF being placed and used, but the access failure rate was still higher than desired. In 2010, a more experienced vascular surgeon was contacted to perform AVF surgery in our most difficult AVF candidates.

RESULTS

Sixty-five AVF were created in 55 patients (67.3 % male). The median age of the patients was 14 (3-18) years. Forty-one (63.1 %) AVF were used successfully, and this number increased from 52.6 to 57.6 to 92.3 % over the three time periods, respectively. Over time, AVF use rates increased and CVC use decreased. By 2012 only 7.7 % of our patients were using a CVC. The primary patency rate was 42.9 % at 1 year; secondary patency rates were 100 and 93.8 % at 1 and 2 years, respectively. Infection and hospitalization rates were higher for CVC than for AVF [0.8 vs. 0.1 infections per access-year (p < 0.001) and 0.9 vs. 0.2 hospitalizations per access-year (p < 0.001)].

CONCLUSIONS

With a dedicated approach and vascular access team it is possible to decrease CVC and increase AVF use in children on hemodialysis. In our study, increased AVF use resulted in decreased access-related infection and hospitalization rates.

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.

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.

Practical aspects of arteriovenous fistula formation in the pediatric population

The principle of "Fistula First" for hemodialysis has been widely adopted among adults with end-stage renal failure (ESRF). UK national targets aim to have 85 % of prevalent patients using permanent access (arteriovenous fistula or graft). Currently, hemodialysis in children relies heavily on central venous catheters (CVC). However, there is significant evidence that arteriovenous fistulae (AVF) are preferable for long-term dialysis in the pediatric population. We describe the principles of fistula formation including pre-operative work-up, surgical techniques for AVF creation, and post-operative monitoring.

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.

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.

Advances in pediatric renal replacement therapy

Advances in the understanding and clinical application of hemodialysis, peritoneal dialysis, and continuous renal replacement therapy have resulted in strategies designed to further improve their safety and efficacy. These advances have been particularly important to children, in whom a variety of clinical and technical issues must be taken into consideration for optimum dialysis across a broad spectrum of patient size and need. This manuscript reviews recent data pertaining to the use of renal replacement therapy, with an emphasis on those aspects of dialysis management that are especially pertinent to pediatric ESRD and acute kidney injury care.

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.

A vascular access team can increase AV fistula creation in pediatric ESRD patients: a single center experience

The National Kidney Foundation Dialysis Outcomes Quality Initiative (NKF-DOQI) recommends the use of a permanent vascular access for pediatric hemodialysis (HD) patients; however, central venous catheters are the most common vascular access used among children. In children receiving HD, central venous catheters, while suboptimal, are the most common vascular access used. As such, it is imperative that pediatric HD providers optimize vascular access techniques. We report outcomes of arteriovenous fistula (AVF) creation by a single surgeon in pediatric HD patients dialyzed at a single center. We further describe our experience and outcomes with the use of the operating microscope in the United States in children receiving HD under 15 kg in weight and as young as 4 years of age. AVF usage rates as well as short- and long-term patency rates can be quite high with proper management. We further illustrate that the Fistula First principles can be applied to the pediatric population in the setting of a single surgeon with single center experience. As such, we have surpassed the current NKF-DOQI recommendation of 50% fistula use in prevalent HD patients.

Retarded hand growth due to a hemodialysis fistula in a young girl

Long-term presence of an arteriovenous hemodialysis fistula (AVF) may lead to alterations in hand perfusion. In the case reported here, a 14-year-old girl developed pain associated with hand ischemia 5 years after a successful kidney transplantation. At age 8 years, she required a period of hemodialysis using an autogenous left upper arm AVF. Compared to the healthy right hand, a smaller ischemic left hand was observed in the presence of a patent AVF. Access flow was 1400 ml/min. Seldinger angiography demonstrated a stenotic brachial artery, and duplex measurements indicated a reversed blood flow in the radial artery. AVF ligation abolished the ischemic symptoms. Distal hypotension due to an impaired arterial inflow combined with a low resistance elbow AVF may result in chronic hypoperfusion of acral portions of the extremity and growth retardation. Access ligation is advised in children with an optimal renal transplant function and a patent elbow AVF suffering from lowered distal tissue perfusion.

Arteriovenous fistulas for hemodialysis access in children and adolescents using the proximal radial artery inflow site

INTRODUCTION

Hemodialysis (HD) for children and adolescents with renal failure is increasingly common in the United States. Consensus opinion views an arteriovenous fistula (AVF) as the best long-term access option, although catheter-based HD remains the most common vascular access in children and has greater risks of complications and higher mortality rates than AVF access. This report reviews our experience with children and adolescents undergoing vascular access operations.

METHODS

We reviewed 721 consecutive vascular access patients who had vascular access surgery by a single surgeon during the previous 5 years. Ten patients 20 years or younger were included in this study. In addition to physical examination, each patient had preoperative vascular ultrasound mapping by the operating surgeon. A radiocephalic AVF (RC-AVF) at the wrist was the first choice for dialysis access when feasible; however, the patients in this report were generally seen after years of intravenous access and venipunctures that necessitated more proximal AVF constructions. A proximal radial artery AVF (PRA-AVF) was our most common choice for vascular access when an RC-AVF was not suitable.

RESULTS

Patient ages were 9 to 20 years (mean, 16). Seven were male. Renal failure was caused by glomerulnephitis in 4 patients, 3 had a history of obstuctive uropathy, 2 were diabetic and one had congenital nephrotic syndrome. Eight patients had PRA-AVFs created, 1 had an RC-AVF, and 1 patient required a transposition AVF. Follow-up was 4 to 56 months (mean, 32 months). Primary, primary-assisted, and cumulative patencies were 77.8%, 100%, and 100% at 24 months. No prosthetic grafts were used in any vascular access patient during the study period.

CONCLUSION

We found HD access in children and adolescents was reliably established through use of a PRA-AVF when an RC-AVF was not feasible. Access sites were often possible through the upper arm cephalic veins and/or with retrograde flow into the forearm. Cumulative (secondary) patency was 100% at 24 months.

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

Recent data indicate that the incidence of end-stage renal disease (ESRD) in pediatric patients (age 0-19 years) has increased over the past two decades. Similarly, the prevalence of ESRD has increased threefold over the same period. Hemodialysis (HD) continues to be the most frequently utilized modality for renal replacement therapy in incident pediatric ESRD patients. The number of children on HD exceeded the sum total of those on peritoneal dialysis and those undergoing pre-emptive renal transplantation. Choosing the best vascular access option for pediatric HD patients remains challenging. Despite a national initiative for fistula first in the adult hemodialysis population, the pediatric nephrology community in the United States of America utilizes central venous catheters as the primary dialysis access for most patients. Vascular access management requires proper advance planning to assure that the best permanent access is placed, seamless communication involving a multidisciplinary team of nephrologists, nurses, surgeons, and interventional radiologists, and ongoing monitoring to ensure a long life of use. It is imperative that practitioners have a long-term vision to decrease morbidity in this unique patient population. This article reviews the various types of pediatric vascular accesses used worldwide and the benefits and disadvantages of these various forms of access.

Arteriovenous fistula for chronic hemodialysis in pediatric candidates for renal transplantation: Technical details and refinements

AVFs may be considered the best type of venous access for chronic hemodialysis in pediatric patients with more than 20 kg who are not likely to receive a kidney transplant or be transitioned to peritoneal dialysis within one yr. The aim of the study was to report the experience in the creation of AVFs in pediatric candidates for renal transplantation using microsurgical vascular techniques, with emphasis on the details of the surgical technique. Forty children underwent 50 fistula creations - 31 radial-cephalic, 11 brachial-cephalic, five brachial-basilic and three saphenous-femoral. The vein was anastomosed to the artery in an end-to-lateral fashion by using two separate 8/0 prolene running sutures. The overall patency rate was 76.0%:22 (70.9%) of the radial-cephalic fistulas, nine (81.8%) of the brachial-cephalic, five (100.0%) of the brachial-basilic and two (66.6%) of the saphenous-femoral. There was no significant difference in patency rates between the brachial-cephalic, brachial-basilic and radial-cephalic fistulas. The incidences of fistula patency were not different for patients weighing <20 kg compared with patients weighing >20 kg. AVF remains as a satisfactory method for providing hemodialysis in children. The utilization of microsurgical techniques with some technical refinements described herein permits the achievement of high fistula patency rates.

Long-term outcome of chronic dialysis in children

As the prevalence of children on renal replacement therapy (RRT) increases world wide and such therapy comprises at least 2% of any national dialysis or transplant programme, it is essential that paediatric nephrologists are able to advise families on the possible outcome for their child on dialysis. Most children start dialysis with the expectation that successful renal transplantation is an achievable goal and will provide the best survival and quality of life. However, some will require long-term dialysis or may return intermittently to dialysis during the course of their chronic kidney disease (CKD). This article reviews the available outcome data for children on chronic dialysis as well as extrapolating data from the larger adult dialysis experience to inform our paediatric practice. The multiple factors that may influence outcome, and, particularly, those that can potentially be modified, are discussed.

Vascular access complications in long-term pediatric hemodialysis patients

Current data demonstrate pediatric patients who remain on hemodialysis (HD) therapy are more likely to be dialyzed via central venous catheters (CVCs) than arteriovenous grafts (AVGs) and fistulae (AVFs). We retrospectively compared complications and health-related quality of life (HRQOL) associated with different vascular access types at two large centers over a 1-year period. Patients included in the study were younger than 25 years of age, weighed >20 kg, and had received HD for at least 3 months. Thirty CVC patients and 21 AVG/AVF patients received a total of 2,393 and 3,506 HD treatments, respectively. The infectious complication rate was higher for CVC patients, who were hospitalized 3.7 days for each 100 HD treatments versus 0.2 days for AVG/AVF patients (p < 0.01). CVC patients also had a much higher rate of access revision, needing 2.7 hospital days every 100 HD treatments compared with 0.2 days for AVG/AVF patients (p < 0.01). HRQOL scores did not differ between groups. Thus, despite similar HRQOL, CVCs were associated with more complications and greater morbidity when compared with AVG/AVFs. These findings further emphasize the need to use AVG/AVFs as primary HD access for pediatric patients expected to receive a long course of maintenance HD.

Patterns of use of vascular catheters for hemodialysis in children in the United States

BACKGROUND

Arteriovenous fistulas (AVFs) and grafts (AVGs) have been associated with improved clinical outcomes in children and adults with end-stage renal disease (ESRD) on maintenance hemodialysis (HD) therapy, but use of vascular catheters is high. Identifying the reasons for the high prevalence of vascular catheters in children on HD therapy is necessary to assess whether targeted interventions may increase the prevalence of AVFs/AVGs.

STUDY DESIGN

Retrospective cohort study.

SETTING & PARTICIPANTS

Children younger than 18 years on HD therapy in the 2001 to 2003 ESRD Clinical Performance Measures (CPM) Projects followed up in the US Renal Data System transplant files through December 31, 2004.

PREDICTOR

Vascular access type and reasons for use of a vascular catheter.

OUTCOMES & MEASUREMENTS

Demographic/clinical characteristics, including the reason provided for use of a vascular catheter, and the association of type of vascular access and (1) patient size and (2) time to kidney transplantation.

RESULTS

Of 1,284 prevalent pediatric CPM patients examined, 529 (41%) had an AVF/AVG and 755 (59%) had a vascular catheter. Of 755 children with a catheter, "small body size" was a commonly listed reason (N = 142); 49% of these children weighed 20 kg or more. Of 53 patients with catheters described as having an "AVF/AVG maturing" and present in the consecutive ESRD CPM project year, 64% had a functioning AVF/AVG the following year. For those with "transplantation scheduled" listed as a reason for a vascular catheter (N = 83), 69% underwent transplantation within 1 year, and median time to transplantation was 115 days. Of all children with vascular catheters (N = 755), 32.2% underwent transplantation within 1 year, and median time to transplantation was 264 days compared with 21.7% and 347 days for those with AVFs/AVGs, respectively (N = 529). Of the 445 incident children in this cohort, 89% had a vascular catheter at dialysis therapy initiation.

LIMITATIONS

Because of study design, only associations can be described.

CONCLUSIONS

Vascular catheter use in children on HD therapy is high. This is partially explained by expeditious transplantation and technical barriers to AVF/AVG placement in small children; however, only one-third of patients with a vascular catheter underwent transplantation within 1 year. Interventions to decrease vascular catheter use in this population may be necessary.

Disparities in fistula maturation persist despite preoperative vascular mapping

BACKGROUND AND OBJECTIVES

Failure to mature (primary failure) of new fistulas remains a major obstacle to increasing the proportion of dialysis patients with fistulas. This failure rate is higher in women than in men, higher in older than in younger patients, and higher in forearm than in upper arm fistulas. These disparities in the frequency of failure to mature may be due in part to marginal vessels in the high-risk groups and should be reduced by routine preoperative vascular mapping.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

A prospective, computerized database was queried retrospectively to evaluate the frequency of primary fistula failure in 205 hemodialysis patients for whom preoperative mapping was obtained. The association between clinical characteristics and risk for primary fistula failure was analyzed by univariate and multiple variable regression analysis.

RESULTS

The overall primary fistula failure rate was 40% (82 of 205 patients). On multiple variable logistic regression, three clinical factors were associated with an increased risk for failure to mature among patients who underwent preoperative vascular mapping: Female gender, age > or =65 yr, and forearm location. The primary fistula failure rate varied from 22% in younger men with an upper arm fistula to 78% in older women with a forearm fistula. Dynamic preoperative vascular measurements (change in peak systolic velocity and resistive index after tight fist clenching) did not differ between patients with mature and immature forearm fistulas.

CONCLUSION

Disparities in fistula maturation persist despite the use of routine preoperative vascular mapping.

Intermediate-term patency of upper arm arteriovenous fistulae for hemodialysis access in children

PURPOSE

The goal of this study was to estimate the 2-year cumulative thrombosis-free survival of basilic vein transposition (BVT) and brachiocephalic fistulae in children.

METHODS

All children who underwent BVT or brachiocephalic fistula construction at a tertiary care children's hospital from June 2001 to July 2006 were reviewed. Kaplan-Meier analysis, log-rank test, and proportional hazards regression were done.

RESULTS

Sixteen children (7 girls) with inadequate forearm veins underwent creation of 18 fistulae (12 BVT, 6 brachiocephalic). Median age was 14 (9-19) years. Mean (+/-SE) operative times for BVT and brachiocephalic fistulae were 3.4 (+/- 0.6) hours and 1.9 (+/-0.4) hours, respectively. The overall 2-year cumulative survival rate was 74% (BVT, 66%; brachiocephalic fistula, 83%). Four fistulae failed (1 brachiocephalic, 3 BVT) and 14 fistulae were censored (5, patent fistula; 4, renal transplantation; 2, unrelated death; 1, elective conversion to peritoneal dialysis; 1, surgical ligation of fistula; 1, lost to follow-up). Of 18 fistulae, 6 underwent additional interventions (4, percutaneous angioplasty; 2, surgical thrombectomy). There were no significant differences in survival times based on fistula type, prior transplant status, age, or operative time.

CONCLUSIONS

Brachiocephalic and BVT fistulae create reliable hemodialysis access for children who have inadequate forearm veins to allow construction of more distal fistulae.

Hemodialysis in children weighing less than 15 kg: a single-center experience

Despite significant technical improvements, hemodialysis in infants with end-stage renal disease (ESRD) is still associated with significant morbidity and mortality. The files of patients weighing less than 15 kg with ESRD who were treated with hemodialysis at our institute between 1995 and 2005 were reviewed for background and treatment characteristics, morbidity and outcome. The study group included 11 patients aged 7-75 months (mean 34.2 months) weighing 7.2-14.9 kg (mean 10.9 kg). Mean duration of dialysis was 11.3 months. Vascular access posed the major problem. Ten patients were dialyzed through a central venous cuffed catheter and one through an arteriovenous fistula. An average of three different vascular accesses was required per patient (range 1-9). Mechanical difficulties were the most common cause of central-line removal (56.5%), followed by infections (15.6%). Major complications causing significant morbidity were intradialytic hemodynamic instability, hyperkalemia, coagulation within the dialysis set, anemia, hypertension, inadequate fluid removal, and recurrent hospitalizations. Analysis of outcome revealed that eight patients underwent successful transplantation, one returned for hemodialysis after 4.5 years due to graft failure, and two died. Hemodialysis is a suitable option for low-weight pediatric patients with ESRD awaiting transplantation when performed in highly qualified centers.

Vascular Access in Children: The Importance of Microsurgery for Creation of Autologous Arteriovenous Fistulae

Microsurgery gives much better immediate and long term results than classical surgery for the creation of direct arteriovenous fistulae, the best chronic access to blood in children.

Clinical Course Associated with Vascular Access Type in a National Cohort of Adolescents Who Receive Hemodialysis: Findings from the Clinical Performance Measures and US Renal Data System Projects

Limited research has described clinical outcomes that are associated with the type of vascular access in pediatric patients who receive maintenance hemodialysis. This retrospective cohort study examined prevalent pediatric patients who were aged 12 to <18 yr and identified in the 2000 ESRD Clinical Performance Measures Project as receiving in-center hemodialysis. Vascular access type as of December 31, 1999, was identified. These patients were linked with 1 yr of data (January 1, 2000, through December 31, 2000) from US Renal Data System standard analytic files that allow for the comparison of rates of hospitalizations and access complications by access type. Of the 418 patients who met inclusion criteria, the mean age was 15.6 yr, 53% were male, 49% were white, the mean time on dialysis was 22 mo, and 42% had a structural/urologic cause of ESRD; 42% of patients had an arteriovenous graft or fistula, and 58% had a vascular catheter. Patients with a vascular catheter as compared with those with a graft or fistula had the following adjusted relative risks (95% confidence interval): 1.84 (1.38 to 2.44) for hospitalization for any cause, 4.74 (2.02 to 11.14) for hospitalization as a result of infection, and 2.72 (2.00 to 3.69) for a complication of vascular access. Vascular catheters are the predominant access type in adolescent patients who receive maintenance hemodialysis and are associated with significantly more hospitalizations and complications.