Standardized definitions for hemodialysis vascular access

Future research directions to improve fistula maturation and reduce access failure

With the increasing prevalence of end-stage renal disease, there is a growing need for hemodialysis. Arteriovenous fistulae (AVF) are the preferred type of vascular access for hemodialysis, but maturation and failure continue to present significant barriers to successful fistula use. AVF maturation integrates outward remodeling with vessel wall thickening in response to drastic hemodynamic changes in the setting of uremia, systemic inflammation, oxidative stress, and pre-existent vascular pathology. AVF can fail due to both failure to mature adequately to support hemodialysis and development of neointimal hyperplasia that narrows the AVF lumen, typically near the fistula anastomosis. Failure due to neointimal hyperplasia involves vascular cell activation and migration and extracellular matrix remodeling with complex interactions of growth factors, adhesion molecules, inflammatory mediators, and chemokines, all of which result in maladaptive remodeling. Different strategies have been proposed to prevent and treat AVF failure based on current understanding of the modes and pathology of access failure; these approaches range from appropriate patient selection and use of alternative surgical strategies for fistula creation, to the use of novel interventional techniques or drugs to treat failing fistulae. Effective treatments to prevent or treat AVF failure require a multidisciplinary approach involving nephrologists, vascular surgeons, and interventional radiologists, careful patient selection, and the use of tailored systemic or localized interventions to improve patient-specific outcomes. This review provides contemporary information on the underlying mechanisms of AVF maturation and failure and discusses the broad spectrum of options that can be tailored for specific therapy.

Peripherally Inserted Central Catheters and Hemodialysis Outcomes

BACKGROUND AND OBJECTIVES

Use of peripherally inserted central catheters has expanded rapidly, but the consequences for patients who eventually require hemodialysis are undefined.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Our national, population-based analysis included 33,918 adult Medicare beneficiaries from the US Renal Data System who initiated hemodialysis with central venous catheters as their sole vascular access in 2010 and 2011. We used linked Medicare claims to identify peripherally inserted central catheter exposures and evaluate the associations of peripherally inserted central catheter placement with transition to working arteriovenous fistulas or grafts and patient survival using a Cox model with time-dependent variables.

RESULTS

Among 33,918 individuals initiating hemodialysis with a catheter as sole access, 12.6% had received at least one peripherally inserted central catheter. Median follow-up was 404 days (interquartile range, 103-680 days). Among 6487 peripherally inserted central catheters placed, 3435 (53%) were placed within the 2 years before hemodialysis initiation, and 3052 (47%) were placed afterward. Multiple peripherally inserted central catheters were placed in 30% of patients exposed to peripherally inserted central catheters. Recipients of peripherally inserted central catheters were more likely to be women and have comorbid diagnoses and less likely to have received predialysis nephrology care. After adjustment for clinical and demographic factors, peripherally inserted central catheters placed before or after hemodialysis initiation were independently associated with lower likelihoods of transition to any working fistula or graft (hazard ratio for prehemodialysis peripherally inserted central catheter, 0.85; 95% confidence interval, 0.79 to 0.91; hazard ratio for posthemodialysis peripherally inserted central catheter, 0.81; 95% confidence interval, 0.73 to 0.89).

CONCLUSIONS

Peripherally inserted central catheter placement was common and associated with adverse vascular access outcomes. Recognition of potential long-term adverse consequences of peripherally inserted central catheters is essential for clinicians caring for patients with CKD.

A modified nontransposed brachiobasilic arteriovenous fistula versus brachiocephalic arteriovenous fistula for maintenance hemodialysis access

OBJECTIVE

With the growing need for reliable and durable upper arm hemodialysis access, we sought to compare the performance of a novel modified nontransposed brachiobasilic arteriovenous fistula (mNT-BBAVF) with that of the more traditional brachiocephalic arteriovenous fistula (BCAVF).

METHODS

Briefly, to construct an mNT-BBAVF, an incision is made on the ulnar side of the elbow. The brachial artery and basilic vein are then isolated, and a side-to-side anastomosis is performed without transposition of the basilic vein. Next, the proximal basilic vein and the perforating veins within the surgical field are ligated. In this study, we retrospectively reviewed the medical records of all patients who underwent either an mNT-BBAVF or a BCAVF between January 2011 and October 2014 to compare 1-year primary unassisted patency, cumulative patency, and complications. We also examined hemodynamic parameters of vessels in each fistula type.

RESULTS

We identified a total of 84 patients: 45 had a BCAVF, and 39 had an mNT-BBAVF. The two groups were well matched for baseline characteristics. Maturation rates at 1 month were 97% for mNT-BBAVF and 96% for BCAVF. The 1-year primary unassisted patency was significantly higher in the mNT-BBAVF group than that in the BCAVF group (87% vs 67%; hazard ratio, 2.86; 95% confidence interval, 1.11-6.40; P = .03), although cumulative patency did not differ (90% vs 73%; hazard ratio, 2.80; 95% confidence interval, 0.98-6.96 ; P = .06). There were no differences in thrombosis, failure of maturation, bleeding, steal syndrome, arm swelling, aneurysm, and stenosis between the two groups during the 12-month study. Importantly, diameters and blood flow volumes of the proximal cephalic vein, distal cephalic vein, and distal basilic vein in patients who received an mNT-BBAVF increased significantly after 12 months. All three vessels met the Kidney Disease Outcomes Quality Initiative (KDOQI) criteria for fistula maturation and were available for dialysis cannulation, whereas only the proximal cephalic vein in the BCAVF group met the maturation criteria and could be used for cannulation.

CONCLUSIONS

mNT-BBAVF appeared to be an effective alternative to BCAVF for upper arm hemodialysis access.

Impact of preoperative ultrasonography findings on the patency rate of vascular access in Japanese hemodialysis patients

Background

Although ultrasonography before a vascular access (VA) operation has become popular in recent years, benchmarks for the diameter or blood flow of arteries or veins are not defined in Japan. The objective of the present study is to analyze the relationship between preoperative US findings and the patency rate of VA in Japanese hemodialysis patients.

Methods

139 patients with end stage kidney disease were enrolled in this study. They had been given primary radiocephalic arteriovenous fistula (AVF) from February 2009 to December 2010 at the Juntendo University Hospital and were followed up over 2 years. We defined the interval from the time of AVF creation until first access thrombosis or any intervention to maintain or restore blood flow as patency time (primary patency). We examined the correlation between the 2-year primary patency rate of VA and the diameter of the radial artery (RA), brachial artery (BA), or cephalic vein at an anastomosis presumptive region by US, the blood flow of RA or BA, as measured by US, age, gender, and primary kidney diseases.

Results

The average patency term was 448.6 ± 271.3 days, with the 1-year and 2-year patency rate as 64.0 and 51.2 %, respectively. The patency rate was significantly lower in elderly patients over the age of 75 and in patients with diabetes mellitus. US findings of 2.0 mm or less in the RA diameter also resulted in a noticeably low patency rate. A multivariate analysis indicated that those factors were risk factors for early VA failure.

Conclusions

Preoperative US findings of the diameter of RA may involve the patency rate of VA, making it appears that an RA of 2.0 mm or more in diameter at an anastomosis region may be more effective for the improvement in the patency rate of VA.

Aortic Arch Calcification Predicts Patency Loss of Arteriovenous Fistula in End-Stage Renal Disease Patients

Aortic arch calcification (AAC) is recognized as an important cardiovascular risk factor in patients with end-stage renal disease (ESRD). The aim of the study was to evaluate the impact of AAC grade on patency rates of arteriovenous fistula (AVF) in this specific population. The data of 286 ESRD patients who had an initial AVF placed were reviewed. The extent of AAC identified on chest radiography was divided into four grades (0–3). The association between AAC grade, other clinical factors, and primary patency of AVF was then analyzed by Cox proportional hazard analysis. The multivariate analysis demonstrated that the presence of AAC grade 2 (hazard ratio (95% confidence interval): 1.80 (1.15–2.84); p = 0.011) and grade 3 (3.03 (1.88–4.91); p < 0.001), and higher level of intact-parathyroid hormone (p = 0.047) were associated with primary patency loss of AVF. In subgroup analysis, which included AVF created by a surgeon assisted with preoperative vascular mapping, only AAC grade 3 (2.41 (1.45–4.00); p = 0.001), and higher intact-parathyroid hormone (p = 0.025) level were correlated with AVF patency loss. In conclusion, higher AAC grade and intact-parathyroid hormone level predicted primary patency loss of AVF in an ESRD population.

The association of endothelial progenitor cell markers with arteriovenous fistula maturation in hemodialysis patients

AIMS

Arteriovenous fistula (AVF) failure is one of the most important clinical problems in end-stage renal disease. Endothelial progenitor cells (EPCs) have a role on vascular angiogenesis and endothelialization. We aimed to investigate the association markers of EPCs on AVF maturation by measuring the surface expressions of CD34, CD309 and CD133 on the monocytes.

METHODS

This prospective observational study was conducted in 54 voluntary patients with end-stage renal disease who were admitted for their first renal replacement therapy and were available for AVF creation. Venography was performed in all patients before AVF creation. Six patients were excluded due to inadequate veins after venographic imaging, and also seven patients were excluded due to postoperative thrombosis. The blood samples were analyzed a day before the fistula operation, and the expressions of CD34, CD133 and CD309 on the surface of monocytes were measured.

RESULTS

Patients were divided into two groups after the evaluation of AVF maturation, as the mature group and the failure group. The CD309 expression level on the monocytes was 338.00 (35.00-479.00) in the mature group; however, it was 36.00 (5.50-237.00) (p 0.031) in the failure group. Multiple logistic regression analyses showed that both BMI and the mean fluorescence intensity level of CD309 expression on monocytes independently predicted AVF maturation.

CONCLUSIONS

The presence of DM and increased BMI negatively correlated with AVF maturation. High intensity of CD309 expression on monocytes was observed in patients with successful AVF maturation.

Retrospective review of arteriovenous fistula success rate in a multi-ethnic Asian population

BACKGROUND

Native vein arteriovenous fistulas (AVFs) are the recommended first-line vascular access in hemodialysis patients. Despite this, AVFs are plagued with unfavorable maturation rates. We conducted a retrospective cohort study to assess the AVF success rate and to identify any significant associating factors.

METHODOLOGY

Demographic and clinical data of all AVFs created from January 2011 to June 2013 at a single center with a multi-ethnic Asian population, were reviewed. The primary outcome was AVF successfully used for hemodialysis (FUSH) at 6 months. Secondary endpoints were the overall FUSH and actual maturation time of the AVFs. Univariate and multivariate analyses were performed to identify factors associated with AVF success.

RESULTS

A total of 375 fistulas were created during the study period (110 radiocephalic, 176 brachiocephalic, 89 brachiobasilic). The mean age was 59.4 ± 12.6 years and 42.9% were females. Seventy-one percent of patients had diabetes, 32.5% had ischemic heart disease and 10.7% had peripheral vascular disease. 246/375 (65.6%) AVFs FUSH by 6 months, and the average AVF maturation time was 16.1 ± 10.7 weeks. Of the 246 AVFs, 11% required secondary procedure to assist their success. Univariate analysis showed that gender (p = 0.035), age (p = 0.018), vein size on pre-operative vein mapping (p = 0.004) and operating surgeon (p = 0.021) were significant factors associated with AVF success. On multivariate analysis, age, pre-operative vein size and operating surgeon were significantly associated with fistula success.

CONCLUSIONS

Reasonable FUSH rates can be achieved in the study patients. Patient age, pre-operative vein mapping size and operating surgeon were shown to influence AVF success rate.

A Retrospective Study of Preferable Alternative Route to Right Internal Jugular Vein for Placing Tunneled Dialysis Catheters: Right External Jugular Vein versus Left Internal Jugular Vein

Background

Right internal jugular vein (IJV) is a preferred access route for tunneled (cuffed) dialysis catheters (TDCs), and both right external jugular vein (EJV) and left IJV are alternative routes for patients in case the right IJV isn’t available for TDC placement. This retrospective study aimed to determine if a disparity exists between the two alternative routes in hemodialysis patients in terms of outcomes of TDCs.

Methods

49 hemodialysis patients who required TDCs through right EJV (n = 21) or left IJV (n = 28) as long-term vascular access were included in this study. The primary end point was cumulative catheter patency. Secondary end points include primary catheter patency, proportion of patients that never required urokinase and incidence of catheter-related bloodstream infections (CRBSI).

Results

A total of 20,870 catheter-days were evaluated and the median was 384 (interquartile range, 262–605) catheter-days. Fewer catheters were removed in the right EJV group than in the left IJV group (P = 0.007). Mean cumulative catheter patency was higher in the right EJV group compared with the left IJV group (P = 0.031). There was no significant difference between the two groups in the incidence of CRBSI, primary catheter patency or proportion of patients that never required urokinase use. Total indwell time of antecedent catheters was identified as an independent risk factor for cumulative catheter patency by Cox regression hazards test with an HR of 2.212 (95% CI, 1.363–3.588; p = 0.001).

Conclusions

Right EJV might be superior to left IJV as an alternative insertion route for TDC placement in hemodialysis patients whose right IJVs are unavailable.

Venous aneurysm complicating arteriovenous fistula access and matrix metalloproteinases

Introduction

An arteriovenous fistula (AVF) for placed for hemodialysis may be burdened by one particular complication—the formation of a venous aneurysm. It has been shown that matrix metalloproteinases (MMPs) and neutrophil gelatinase-associated lipocalin (NGAL) could represent markers of disease in both venous and arterial vessels.

Materials and methods

This case study reports a rare case of enormous venous aneurysm-correlated MMP and NGAL levels in a woman with an AVF.

Results

Significantly higher levels of plasma MMP-1, MMP-8, MMP-9, and NGAL were detected in this patient during aneurysmal evaluation before the surgery; these levels significantly decreased 1, 3 and 6 months after surgery.

Conclusion

MMP and NGAL levels could represent a marker of aneurysmal disease, and their plasma evaluation could help physicians to stratify the risk of complications in patients with an AVF.

Should patients be on antithrombotic medication for their first arteriovenous fistulae?

PURPOSE

Evidence on the effect of antithrombotic medication on reducing early and late fistula failure is inconclusive. Antithrombotic use carries risks in patients with end-stage renal failure and could increase the risk of needling complications as a result of bleeding. The objectives of this study are to determine the effect of antithrombotic agents on early and late fistula failure and on the risk of interrupted start of cannulation of the fistula.

METHODS

Retrospective analysis of two prospectively maintained databases of access operations and dialysis sessions of 671 patients who had their first fistula between 2004 and 2011. Early failure was defined as failure to reach six consecutive dialysis sessions at any time with two needles on the index form of access. Fistula survival was defined as the time from when the fistula was first used to fistula abandonment.

RESULTS

Primary failure was similar between patients on antiplatelet (18.8%), anticoagulants (18.4%) or no antithrombotic medication (18.8%; p = 0.998). Antithrombotic medication did not have an effect on AVF survival (p = 0.86). Antithrombotic medication did not increase complicated cannulation rates, defined as the percentage of patients failing to achieve six uninterrupted dialysis sessions from the start (p = 0.929).

CONCLUSIONS

Antithrombotic medication had no significant effect on primary failure rate, long-term fistula survival or initial complicated cannulation rates in our study. This suggests that patients already on antithrombotic medication can continue taking them without increasing the risk of interrupted dialysis.

Percutaneous creation of an arteriovenous fistula for hemodialysis access

PURPOSE

Arteriovenous fistulae (AVFs) created by conventional surgical techniques are associated with suboptimal short- and long-term patency. This study investigated the feasibility of creating fistulae with a percutaneous system and evaluated the utility of percutaneous AVFs (pAVFs) in providing hemodialysis access.

MATERIALS AND METHODS

From August 2012 to September 2013, a percutaneous system was used to attempt pAVF creation between the proximal ulnar artery and a closely associated ulnar vein in 33 patients. Technical success, adverse events, and time to pAVF maturity were recorded, as was clinical effectiveness at 6 months.

RESULTS

A pAVF was successfully created in 32 of 33 patients (97%). Four patients died during the follow-up period from causes unrelated to the procedure; one patient was lost to follow-up. Of the remaining 27 patients, 24 were undergoing successful dialysis via their pAVF at 6 months. Two additional patients had usable access but did not initiate dialysis during the study. One spontaneous pAVF thrombosis occurred in a patient with preexisting central vein stenosis. Cumulative pAVF patency at 6 months was 96.2% (26 of 27; standard error, 3.8%). Mean time to pAVF maturation was 58 days (range, 37-168 d). There was one serious procedure-related adverse event and five minor procedure-related adverse events.

CONCLUSIONS

Although larger studies are required to validate efficacy in a wide range of patients, this study demonstrates hemodialysis access successfully created with an endovascular catheter-based system. Patency of pAVFs and time to maturation were superior to published results of surgical techniques.

Epidemiology of haemodialysis catheter complications: a survey of 865 dialysis patients from 14 haemodialysis centres in Henan province in China

OBJECTIVES

To investigate the incidence rates and risk factors for catheter-related complications in different districts and populations in Henan Province in China.

DESIGN

Cross-sectional.

SETTING

Fourteen hospitals in Henan Province.

PARTICIPANTS

865 patients with renal dysfunction undergoing dialysis using catheters between October 2013 and October 2014.

MAIN OUTCOME MEASURES

The main outcome measures were complications, risk factors and patient characteristics. Catheter-related complications included catheter-related infection (catheter exit-site infection, catheter tunnel infection and catheter-related bloodstream infection), catheter dysfunction (thrombosis, catheter malposition or kinking, and fibrin shell formation) and central vein stenosis.

RESULTS

The overall incidence rate was 7.74/1000 catheter-days, affecting 38.61% of all patients, for catheter infections, 10.58/1000 catheter-days, affecting 56.65% of all patients, for catheter dysfunction, and 0.68/1000 catheter-days, affecting 8.79% of all patients, for central vein stenosis. Multivariate analysis showed that increased age, diabetes, primary educational level or below, rural residence, lack of a nephropathy visit before dialysis and pre-established permanent vascular access, not taking oral drugs to prevent catheter thrombus, lower serum albumin levels and higher ferritin levels were independently associated with catheter infections. Rural residence, not taking oral drugs to prevent thrombus, lack of an imaging examination after catheter insertion, non-tunnel catheter type, lack of medical insurance, lack of nephropathy visit before dialysis and pre-established permanent vascular access, left-sided catheter position, access via the femoral vein and lower haemoglobin level were independently associated with catheter dysfunction. Diabetes, lack of nephropathy visit before dialysis and pre-established permanent vascular access, lack of oral drugs to prevent catheter thrombus, left-sided catheter location and higher number of catheter insertions, were independently associated with central vein stenosis.

CONCLUSIONS

The rate of catheter-related complications was high in patients with end-stage renal disease in Henan Province. Our finding suggest that strategies should be implemented to decrease complication rates.

Preoperative vascular access evaluation for haemodialysis patients

BACKGROUND

Haemodialysis treatment requires reliable vascular access. Optimal access is provided via functional arteriovenous fistula (fistula), which compared with other forms of vascular access, provides superior long-term patency, requires few interventions, has low thrombosis and infection rates and cost. However, it has been estimated that between 20% and 60% of fistulas never mature sufficiently to enable haemodialysis treatment. Mapping blood vessels using imaging technologies before surgery may identify vessels that are most suitable for fistula creation.

OBJECTIVES

We compared the effect of conducting routine radiological imaging evaluation for vascular access creation preoperatively with standard care without routine preoperative vessel imaging on fistula creation and use.

SEARCH METHODS

We searched Cochrane Kidney and Transplant's Specialised Register to 14 April 2015 through contact with the Trials' Search Co-ordinator using search terms relevant to this review.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) that enrolled adult participants (aged ≥ 18 years) with chronic or end-stage kidney disease (ESKD) who needed fistulas (both before dialysis and after dialysis initiation) that compared fistula maturation rates relating to use of imaging technologies to map blood vessels before fistula surgery with standard care (no imaging).

DATA COLLECTION AND ANALYSIS

Two authors assessed study quality and extracted data. Dichotomous outcomes, including fistula creation, maturation and need for catheters at dialysis initiation, were expressed as risk ratios (RR) with 95% confidence intervals (CI). Continuous outcomes, such as numbers of interventions required to maintain patency, were expressed as mean differences (MD). We used the random-effects model to measure mean effects.

MAIN RESULTS

Four studies enrolling 450 participants met our inclusion criteria. Overall risk of bias was judged to be low in one study, unclear in two, and high in one.There was no significant differences in the number of fistulas that were successfully created (4 studies, 433 patients: RR 1.06, 95% CI 0.95 to 1.28; I² = 76%); the number of fistulas that matured at six months (3 studies, 356 participants: RR 1.11, 95% CI 0.98 to 1.25; I² = 0%); number of fistulas that were used successfully for dialysis (2 studies, 286 participants: RR 1.12, 95% CI 0.99 to 1.28; I² = 0%); the number of patients initiating dialysis with a catheter (1 study, 214 patients: RR 0.66, 95% CI 0.42 to 1.04); and in the rate of interventions required to maintain patency (1 study, 70 patients: MD 14.70 interventions/1000 patient-days, 95% CI -7.51 to 36.91) between the use of preoperative imaging technologies compared with standard care (no imaging).

AUTHORS' CONCLUSIONS

Based on four small studies, preoperative vessel imaging did not improve fistula outcomes compared with standard care. Adequately powered prospective studies are required to fully answer this question.

Influência do diabetes mellitus sobre a perviedade da fístula arteriovenosa para hemodiálise

ResumoContextoA incapacidade das fístulas arteriovenosas (FAVs) atenderem aos quesitos mínimos para realização da hemodiálise (HD) corresponde a uma das maiores causas de morbidade nos pacientes em terapia renal substitutiva. Identificar os fatores de risco associados com a falência do acesso vascular é fundamental para o manejo e sucesso da terapia hemodialítica.ObjetivoComparar o tempo médio de patência e a sobrevida das fístulas arteriovenosas realizadas nos pacientes portadores de diabetes mellitus com pacientes não portadores de diabetes mellitus (DM) em HD.MétodosTrata-se de um estudo retrospectivo observacional, no qual foram observados os prontuários médicos de todos os pacientes em HD no Hospital Santa Casa de Misericórdia de Ponta Grossa, no período de fevereiro de 2014. Foram analisados dados clínicos referentes à confecção, manutenção e utilização das FAVs como adjuvante na terapia dialítica, comparando o tempo médio de patência das fístulas em uso para HD, bem como a sobrevida das FAVs ocluídas. Os pacientes selecionados foram divididos em dois grupos para comparação, conforme a presença ou ausência de DM.ResultadosOs indivíduos do Grupo DM apresentaram maior média de idade (59,97 ± 10,12), menor tempo de acompanhamento no serviço de hemodiálise (25,42 ± 21,03 meses), menor tempo médio até a oclusão da fístula arteriovenosa (9,03 ± 11,60 meses) e menor média de sobrevida dos acessos vasculares em 24 meses (50,25%).ConclusõesO estudo concluiu que para os pacientes diabéticos houve um menor tempo médio da patência das FAVs e menor taxa de sobrevida dos acessos em 24 meses.

Benefits and harms of citrate locking solutions for hemodialysis catheters: a systematic review and meta-analysis

BACKGROUND

Citrate has theoretical advantages over heparin for locking hemodialysis central venous catheters (CVCs), but the comparative effectiveness of these agents is not clear.

OBJECTIVES

1) To compare the benefits and harms of citrate versus heparin locking solutions among patients undergoing hemodialysis through CVCs; 2) to appraise methodological quality of the supporting evidence.

DATA SOURCES

CENTRAL, MEDLINE, EMBASE, CINAHL, ISI Web of Science, and nephrology conference abstracts.

STUDY ELIGIBILITY PARTICIPANTS AND INTERVENTIONS

We included randomized, parallel arm clinical trials that enrolled adult patients (>18 years) receiving chronic hemodialysis through CVCs using a citrate locking solution. We excluded studies in which citrate was combined with other agents, such as antibiotics.

APPRAISAL AND SYNTHESIS METHODS

We used the GRADE approach to systematic reviews and quality appraisal. Two reviewers performed data extraction independently and in duplicate. We pooled count data using generic inverse variance with random-effects models, and used fixed-effect models when only two studies were available for pooling. Subgroups included low (≤5%) vs. higher (≥30%) citrate.

RESULTS

We screened 600 citations. Forty-one proceeded to full-text screen; 5 met inclusion criteria. Studies included between 19 and 291 participants (Median N = 61) followed for a total of 174.6 catheter-years; 2 were multi-centred trials. Three studies assessed all-cause mortality; the pooled relative risk for death was 0.71 (95% CI = 0.42-1.24; p = 0.21; I(2) = 0%). The rate ratio for bacteremic episodes was 0.54 (95% CI = 0.23-1.29; p = 0.16; I(2) = 65%) while the rate ratio for bleeding was 0.48 (95% CI = 0.3-0.75; p = 0.001;I I(2) = 5%). Rates of catheter exchange/replacement, all-cause hospitalization and in-situ thrombolysis were not significantly different between groups in any of the pooled analyses. Risk of bias within pooled studies was low.

LIMITATIONS

Outcome definitions varied across studies. Imprecision due to small sample sizes and low event rates reduce our overall confidence in the pooled effect estimates.

IMPLICATIONS

Benefits and harms of citrate vs. heparin locking solutions remain unclear; larger studies and standardization of outcome measurement and reporting are warranted.

TRIAL REGISTRATION

Protocol Registration Number: CRD42013004781.

Novel therapies for hemodialysis vascular access dysfunction: myth or reality?

Hemodialysis vascular access dysfunction is a major source of morbidity for patients with ESRD. Development of effective approaches to prevent and treat vascular access failure requires an understanding of the underlying mechanisms, suitable models for preclinical testing, systems for targeted delivery of interventions to maximize efficacy and minimize toxicity, and rigorous clinical trials that use appropriate outcome measures. This article reviews the substantial progress and ongoing challenges in developing novel treatments for arteriovenous vascular access failure and focuses on localized rather than systemic interventions.

A single institutional experience of conversion of non-tunneled to tunneled hemodialysis catheters: a comparison to de novo placement

PURPOSE

To compare the outcomes of conversion of non-tunneled to tunneled hemodialysis catheters with de novo placement of tunneled catheters and to determine the effect of time to conversion of non-tunneled to tunneled catheters on the incidence of complications.

MATERIALS AND METHODS

A retrospective data analyses was performed on 1,154 patients who had de novo placement of tunneled hemodialysis catheters (control group) and 254 patients who underwent conversion of non-tunneled to tunneled catheters (study group). The outcomes including technical complications, infection, and catheter dysfunction were compared between the two groups.

RESULTS

The technical success rate was 100 % in both the groups with no complications recorded at the time of procedure or within 24 h of insertion. The most common complication encountered in both the groups was catheter dysfunction (15.6 % in controls and 18.1 % in study). Infection rates/100 catheter days for the control and study groups were 0.17 and 0.19, respectively. Infection-free survival was not statistically different between the two groups. The time spent with non-tunneled catheter prior to conversion did not significantly alter the rates of catheter dysfunction and infection in the study group.

CONCLUSION

The efficacy and safety of conversion of non-tunneled to tunneled hemodialysis catheters are similar to de novo placement with no difference in the rates of technical success, catheter dysfunction, or infection. However, the exchange of non-tunneled to tunneled catheter can help in preservation of veins for future vascular access, which is of vital importance in patients with chronic renal disease.

Cumulative patency of contemporary fistulas versus grafts (2000-2010)

BACKGROUND AND OBJECTIVES

Comparisons of fistulas and grafts often overlook the high primary failure rate of fistulas. This study compared cumulative patency (time from access creation to permanent failure) of fistulas and grafts.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Vascular accesses of 1140 hemodialysis patients from two centers (Toronto and London, Ontario, Canada, 2000-2010) were analyzed. Cumulative patency was compared between groups using Kaplan-Meier survival curves and log-rank tests. Hazard ratios (HRs) for fistula failure relative to grafts and 95% confidence intervals (95% CIs) are reported.

RESULTS

There were 1012 (88.8%) fistulas and 128 (11.2%) grafts. The primary failure rate was two times greater for fistulas than for grafts: 40% versus 19% (P<0.001). Cumulative patency did not differ between fistulas and grafts for the patients' first access (median, 7.4 versus 15.0 months, respectively [HR, 0.99; 95% CI, 0.79-1.23; P=0.85]) or for 600 with a subsequent access (7.0 versus 9.0 months [HR, 0.93; 95% CI, 0.77-1.13; P=0.39]). However, when primary failures were excluded, cumulative patency became significantly longer for fistulas than for grafts for both first and subsequent accesses (61.9 versus 23.8 months [HR, 0.56; 95% CI, 0.43-0.74; P<0.001] and 42.8 versus 15.9 months [HR, 0.56; 95% CI, 0.44-0.72; P<0.001]). Results were similar for forearm and upper-arm accesses. Compared with functioning fistulas, grafts necessitated twice as many angioplasties (1.4 versus 3.2/1000 days, respectively; P<0.001) and significantly more thrombolysis interventions (0.06 versus 0.98/1000 days; P<0.001) to maintain patency once matured and successfully used for dialysis.

CONCLUSIONS

Cumulative patency did not differ between fistulas and grafts; however, grafts necessitated more interventions to maintain functional patency.

Care of undocumented-uninsured immigrants in a large urban dialysis unit

Background

Medical, ethical and financial dilemmas may arise in treating undocumented-uninsured patients with end-stage renal disease (ESRD). Hereby we describe the 10-year experience of treating undocumented-uninsured ESRD patients in a large public dialysis-unit.

Methods

We evaluated the medical files of all the chronic dialysis patients treated at the Tel-Aviv Medical Center between the years 2000–2010. Data for all immigrant patients without documentation and medical insurance were obtained. Clinical data were compared with an age-matched cohort of 77 insured dialysis patients.

Results

Fifteen undocumented-uninsured patients were treated with chronic scheduled dialysis therapy for a mean length of 2.3 years and a total of 4953 hemodialysis sessions, despite lack of reimbursement. All undocumented-uninsured patients presented initially with symptoms attributed to uremia and with stage 5 chronic kidney disease (CKD). In comparison, in the age-matched cohort, only 6 patients (8%) were initially evaluated by a nephrologist at stage 5 CKD. Levels of hemoglobin (8.5 ± 1.7 versus 10.8 ± 1.6 g/dL; p < 0.0001) and albumin (33.8 ± 4.8 versus 37.7 ± 3.9 g/L; p < 0.001) were lower in the undocumented-uninsured dialysis patients compared with the age-matched insured patients at initiation of hemodialysis therapy. These significant changes were persistent throughout the treatment period. Hemodialysis was performed in all the undocumented-uninsured patients via tunneled cuffed catheters (TCC) without higher rates of TCC-associated infections. The rate of skipped hemodialysis sessions was similar in the undocumented-uninsured and age-matched insured cohorts.

Conclusions

Undocumented-uninsured dialysis patients presented initially in the advanced stages of CKD with lower levels of hemoglobin and worse nutritional status in comparison with age-matched insured patients. The type of vascular access for hemodialysis was less than optimal with regards to current guidelines. There is a need for the national and international nephrology communities to establish a policy concerning the treatment of undocumented-uninsured patients with CKD.

Diagnosis of arteriovenous fistula dysfunction

Arteriovenous fistula (AVF) dysfunction remains a major contributor to the morbidity and mortality of hemodialysis patients. The failure of a newly created AVF to mature and development of stenosis in an established AVF are two common clinical predicaments. The goal is to identify a dysfunctional AVF early enough to intervene in a timely manner to either assist with the maturation process or to prevent thrombosis. The currently available tools in our armamentarium include clinical evaluation, physical examination of the AVF, and surveillance tests. Physical examination has been recognized as a simple and cost-effective tool, but is often not implemented either because of lack of training or time constraints. Surveillance tests include measurement of access flow or pressure as a surrogate marker of AVF dysfunction. Surveillance tests often require expensive equipment, additional personnel, and are controversial. Currently, there are guidelines and recommendations to include all of these measures while evaluating an AVF. Implementing judicious use of these tools in clinical practice can facilitate early diagnosis for timely intervention in the appropriate population. Furthermore, this strategy may avoid unnecessary interventions and assist with healthcare cost containment.

Effect of fish oil supplementation on graft patency and cardiovascular events among patients with new synthetic arteriovenous hemodialysis grafts: a randomized controlled trial

CONTEXT

Synthetic arteriovenous grafts, an important option for hemodialysis vascular access, are prone to recurrent stenosis and thrombosis. Supplementation with fish oils has theoretical appeal for preventing these outcomes.

OBJECTIVE

To determine the effect of fish oil on synthetic hemodialysis graft patency and cardiovascular events.

DESIGN, SETTING, AND PARTICIPANTS

The Fish Oil Inhibition of Stenosis in Hemodialysis Grafts (FISH) study, a randomized, double-blind, controlled clinical trial conducted at 15 North American dialysis centers from November 2003 through December 2010 and enrolling 201 adults with stage 5 chronic kidney disease (50% women, 63% white, 53% with diabetes), with follow-up for 12 months after graft creation.

INTERVENTIONS

Participants were randomly allocated to receive fish oil capsules (four 1-g capsules/d) or matching placebo on day 7 after graft creation.

MAIN OUTCOME MEASURE

Proportion of participants experiencing graft thrombosis or radiological or surgical intervention during 12 months' follow-up.

RESULTS

The risk of the primary outcome did not differ between fish oil and placebo recipients (48/99 [48%] vs 60/97 [62%], respectively; relative risk, 0.78 [95% CI, 0.60 to 1.03; P = .06]). However, the rate of graft failure was lower in the fish oil group (3.43 vs 5.95 per 1000 access-days; incidence rate ratio [IRR], 0.58 [95% CI, 0.44 to 0.75; P < .001]). In the fish oil group, there were half as many thromboses (1.71 vs 3.41 per 1000 access-days; IRR, 0.50 [95% CI, 0.35 to 0.72; P < .001]); fewer corrective interventions (2.89 vs 4.92 per 1000 access-days; IRR, 0.59 [95% CI, 0.44 to 0.78; P < .001]); improved cardiovascular event-free survival (hazard ratio, 0.43 [95% CI, 0.19 to 0.96; P = .04]); and lower mean systolic blood pressure (-3.61 vs 4.49 mm Hg; difference, -8.10 [95% CI, -15.4 to -0.85]; P = .01).

CONCLUSIONS

Among patients with new hemodialysis grafts, daily fish oil ingestion did not decrease the proportion of grafts with loss of native patency within 12 months. Although fish oil improved some relevant secondary outcomes such as graft patency, rates of thrombosis, and interventions, other potential benefits on cardiovascular events require confirmation in future studies.

TRIAL REGISTRATION

isrctn.org Identifier: ISRCTN15838383.

Complications of arteriovenous fistulae: beyond venous stenosis

Vascular access is the lifeline of hemodialysis patients. Currently, arteriovenous fistulae and grafts are considered permanent options for vascular access, and they share common access problems. The successful creation of a permanent vascular access depends on patient characteristics, vessel parameters, and possibly genetic factors. Utilization of a dialysis access at least 3 times a week leads to significant wear and tear of the access. The buttonhole technique is associated with a higher incidence of infection, and evidence regarding various perceived advantages remain contradictory. Infiltration and aneurysm formation of an access are common, and the literature on its impact on vascular access outcomes is limited. A patient who undergoes hemodialysis often requires multiple accesses during his or her lifetime, and the maintenance of a persistent vascular access may require creative solutions. Intensified research is crucial to comprehending the pathophysiology and treatment options for some of the common problems of vascular accesses.