Hemodialysis Vascular Access Training and Practices Are Key to Improved Access Outcomes

A comparison of arteriovenous fistula failure between Malaysian and Australian and New Zealand participants enrolled in the FAVOURED trial

AIM

To describe and compare de novo arteriovenous fistula (AVF) failure rates between Australia and New Zealand (ANZ), and Malaysia.

BACKGROUND

AVFs are preferred for haemodialysis access but are limited by high rates of early failure.

METHODS

A post hoc analysis of 353 participants from ANZ and Malaysia included in the FAVOURED randomised-controlled trial undergoing de novo AVF surgery was performed. Composite AVF failure (thrombosis, abandonment, cannulation failure) and its individual components were compared between ANZ (n = 209) and Malaysian (n = 144) participants using logistic regression adjusted for patient- and potentially modifiable clinical factors.

RESULTS

Participants' mean age was 55 ± 14.3 years and 64% were male. Compared with ANZ participants, Malaysian participants were younger with lower body mass index, higher prevalence of diabetes mellitus and lower prevalence of cardiovascular disease. AVF failure was less frequent in the Malaysian cohort (38% vs 54%; adjusted odds ratio (OR) 0.53, 95% confidence interval (CI) 0.31-0.93). This difference was driven by lower odds of cannulation failure (29% vs 47%, OR 0.45, 95% CI 0.25-0.80), while the odds of AVF thrombosis (17% vs 20%, OR 1.24, 95% CI 0.62-2.48) and abandonment (25% vs 23%, OR 1.17, 95% CI 0.62-2.16) were similar.

CONCLUSIONS

The risk of AVF failure was significantly lower in Malaysia compared to ANZ and driven by a lower risk of cannulation failure. Differences in practice patterns, including patient selection, surgical techniques, anaesthesia or cannulation techniques may account for regional outcome differences and warrant further investigation.

Customizable modification of banding with external stenting for arteriovenous fistula flow reduction

We performed a single-center retrospective study of prospectively collected data for all patients who had flow reduction surgery with FRAME FR between November 2020 and January 2021. Ten patients had arteriovenous fistula flow reduction surgery with this technique. One patient had a distal fistula, whereas nine were within the cubital fossa. In nine patients the device was applied over the postanastomotic arteriovenous fistula outflow vein and in one in the preanastomotic radial artery. Technical success was achieved in all patients with a median flow reduction from 2150 to 825 mL/min. There were no wound or device-specific complications.

Evolution of Vascular Access Use among Incident Patients during the First Year on Hemodialysis: A National Cohort Study

Background

Although the arteriovenous fistula (AVF) confers superior benefits over central venous catheters (CVCs), utilization rates remain low among prevalent patients on hemodialysis (HD). The goal of this study was to determine the evolution of vascular access type in the first year of dialysis and identify factors associated with conversion from CVC to a functioning AVF.

Methods

We studiedadult patients (n=610) who began HD between the January 1, 2015 and December 31, 2016 and were treated for at least 90 days, using data from the National Kidney Disease Clinical Patient Management System in the Irish health system. Prevalence of vascular access type was determined at days 90 and 360 after dialysis initiation and at 30-day intervals. Multivariable logistic regression explored factors associated with CVC at day 90, and Cox regression evaluated predictors of conversion from CVC to AVF on day 360.

Results

CVC use was present in 77% of incident patients at day 90, with significant variation across HD centers (from 63% to 91%, P<0.001), which persisted after case-mix adjustment. From day 90 to day 360, AVF use increased modestly from 23% to 41%. Conversion from CVC to AVF increased over time, but the likelihood was lower for older patients (for age >77 years versus referent, adjusted hazard ratio [HR], 0.43; 95% CI, 0.19 to 0.96), for patients with a lower BMI (per unit decrease in BMI, HR, 0.95; 95% CI, 0.93 to 0.98), and varied significantly across HD centers (from an HR of 0.25 [95% CI, 0.08 to 0.74] to 2.09 [95% CI, 1.04 to 4.18]).

Conclusion

CVCs are the predominant type of vascular access observed during the first year of dialysis, with low conversion rates from CVC to AVF. There is substantial center variation in the Irish health system that is not explained by patient-related factors alone.

Comparison of surgical versus percutaneously created arteriovenous hemodialysis fistulas

OBJECTIVE

The aim of the present study was to compare the results between percutaneous arteriovenous fistulas (p-AVFs) created with the Ellipsys device (Ellipsys Vascular Access System; Avenu Medical, San Juan Capistrano, Calif) and surgical arteriovenous fistulas (s-AVFs).

METHODS

A single-center retrospective comparative study of the first 107 patients who had undergone p-AVF creation with the Ellipsys system from May 2017 to May 2018 with an equal number of consecutive patients who had undergone s-AVF creation in our center during the same period. The primary endpoints included the maturation and patency rates. The secondary endpoints were reintervention, risk of infection, and the incidence of steal syndrome and aneurysm formation.

RESULTS

The demographic, hypertension, and diabetes data were similar for both groups. The only difference between the two groups was that more p-AVF patients had already been receiving hemodialysis (61% vs 47%; P < .05). The p-AVFs showed superior maturation rates at 6 weeks (65% vs 50%; P = .01). The primary patency rates were greater for the s-AVFs at 12 months (86% vs 61%; P < .01). However, primary patency was comparable between the two groups at 24 months (52% vs 55%; P = .48). No significant difference was found in the secondary patency rates at 12 (90% vs 91%) and 24 (88% vs 91%) months. At the 2-year follow-up point, the rate of percutaneous reintervention was similar; however, the s-AVFs had required more frequent surgical revision (36% vs 17%; P = .01). Issues with wound healing and infection were also more frequent with s-AVFs (9% vs 0.9%; P < .01).

CONCLUSIONS

Fistulas created percutaneously with the Ellipsys system showed superior maturation rates and similar patency with s-AVFs created in an experienced high-volume vascular surgery practice. p-AVFs had a lower risk of wound healing issues, infection, and surgical revision. Larger, prospective, randomized multicenter studies are needed to confirm these findings.

Supply and Distribution of Vascular Access Physicians in the United States: A Cross-Sectional Study

Background

Because functioning permanent vascular access (arteriovenous fistula [AVF] or arteriovenous graft [AVG]) is crucial for optimizing patient outcomes for those on hemodialysis, the supply of physicians placing vascular access is key. We investigated whether area-level demographic and healthcare market attributes were associated with the distribution and supply of AVF/AVG access physicians in the United States.

Methods

A nationwide registry of physicians placing AVFs/AVGs in 2015 was created using data from the United States Renal Data System and the American Physician Association's Physician Masterfile. We linked the registry information to the Area Health Resource File to assess the supply of AVF/AVG access physicians and their professional attributes by hospital referral region (HRR). Bivariate analysis and Poisson regression were performed to examine the relationship between AVF/AVG access physician supply and demographic, socioeconomic, and health resource conditions of HRRs. The setting included all 50 states. The main outcome was supply of AVF/AVG access physicians, defined as the number of physicians performing AVF and/or AVG placement per 1000 prevalent patients with ESKD.

Results

The majority of vascular access physicians were aged 45-64 (average age, 51.6), male (91%), trained in the United States (76%), and registered in a surgical specialty (74%). The supply of physicians varied substantially across HRRs. The supply was higher in HRRs with a higher percentage white population (β=0.44; SEM=0.14; P=0.002), lower unemployment rates (β=-10.74; SEM=3.41; P=0.002), and greater supply of primary care physicians (β=0.18; SEM=0.05; P=0.001) and nephrologists (β=15.89; SEM=1.22; P<0.001).

Conclusions

Geographic variation was observed in the supply of vascular access physicians. Higher supply of such specialist physicians in socially and economically advantaged areas may explain disparities in vascular access and outcomes in the United States and should be the subject of further study and improvement.

Assessment of Use of Arteriovenous Graft vs Arteriovenous Fistula for First-time Permanent Hemodialysis Access

Importance

Initial hemodialysis access with arteriovenous fistula (AVF) is associated with superior clinical outcomes compared with arteriovenous graft (AVG) and should be the procedure of choice whenever possible. To address the national underuse of AVF in the United States, the Centers for Medicare & Medicaid has established an AVF goal of 66% or greater in 2009.

Objective

To explore contemporary practice patterns and physician characteristics associated with high AVG use compared with AVF use.

Design, Setting, and Participants

This review of 100% Medicare Carrier claims between January 1, 2016, and December 31, 2017, includes both inpatient and outpatient Medicare claims data. All patients undergoing initial permanent hemodialysis access placement with an AVF or AVG were included. All surgeons performing more than 10 hemodialysis access procedures during the study period were analyzed.

Exposures

Placement of an AVF or AVG for initial permanent hemodialysis access.

Main Outcomes and Measures

A surgeon-level AVG (vs AVF) use rate was calculated for all included surgeons. Hierarchical logistic regression modeling was used to identify patient-level and surgeon-level factors associated with AVG use.

Results

A total of 85 320 patients (median age, 70 [range, 18-103] years; 47 370 men [55.5%]) underwent first-time hemodialysis access placement, of whom 66 489 (77.9%) had an AVF and 18 831 (22.1%) had an AVG. Among the 2397 surgeons who performed more than 10 procedures per year, the median surgeon level AVG use rate was 18.2% (range, 0.0%-96.4%). However, 498 surgeons (20.8%) had an AVG use rate greater than 34%. After accounting for patient characteristics, surgeon factors that were independently associated with AVG use included more than 30 years of clinical practice (vs 21-30 years; odds ratio, 0.85 [95% CI, 0.75-0.96]), metropolitan setting (odds ratio, 1.25 [95% CI, 1.02-1.54]), and vascular surgery specialty (vs general surgery; odds ratio, 0.77 [95% CI, 0.69-0.86]). Surgeons in the Northeast region had the lowest rate of AVG use (vs the South; odds ratio, 0.83 [95% CI, 0.73-0.96]). First-time hemodialysis access benchmarking reports for individual surgeons were created for potential distribution.

Conclusions and Relevance

In this study, one-fifth of surgeons had an AVG use rate above the recommended best practices guideline of 34%. Although some of these differences may be explained by patient referral practices, sharing benchmarked performance data with surgeons could be an actionable step in achieving more high-value care in hemodialysis access surgery.

Dialysis Access: At the Intersection of Policy, Innovation, and Clinical Care

The Advancing American Kidney Health executive order aims to reduce the incidence of end-stage kidney disease, promote home dialysis therapies, increase the number of kidney transplants, and encourage innovation in new technologies, evidence-based practice, and early detection of kidney disease. Improvements in dialysis access care are essential to the success and expansion of this program, and to being able to provide high-quality, cost-efficient care to this patient population. Specifically, the need for expanded access to home dialysis will require surgeons and interventionalists to become proficient and trained in peritoneal dialysis catheter placement and for the referral process to be streamlined to accommodate the increased interest in this modality. In addition, new technologies, namely percutaneous fistula creation, bioengineered vessels, and a variety of interventions to reduce arteriovenous stenosis, will hopefully allow for timely and durable vascular access options that will support implementation of the executive order.

Prognosis of Vascular Access in Haemodialysis Patients with Autosomal Dominant Polycystic Kidney Disease

Vascular diseases are commonly observed in patients with autosomal dominant polycystic kidney disease (ADPKD). We aim to investigate the differences in the risk for arteriovenous fistula or graft (AVF/AVG) dysfunction in haemodialysis (HD) patients with and without ADPKD. 557 ADPKD and 1671 non-ADPKD patients were enrolled in the study after propensity score matching. The primary outcome measure is the incidence rate of AVF/AVG dysfunction. The incidence rates and risks of AVF/AVG dysfunction (per 100 person-years) for ADPKD and non-ADPKD patients were (1) 38.83 and 48.99 [SHR = 0.79, P = 0.137], respectively, for within 90 days, (2) 45.85 and 51.31 [SHR = 0.90, P = 0.300], respectively, for within 180 days, (3) 44.42 and 41.40 [SHR = 1.08, P = 0.361], respectively, for within the first year, (4) 27.38 and 24.69 [SHR = 1.09, P = 0.168], respectively, for within 5 years, (5) 17.35 and 13.80 [SHR = 1.19, P = 0.045], respectively, for between the 1st and 10th year, and (6) 25.40 and 21.22 [SHR = 1.14, P = 0.031], respectively, for all periods. ADPKD patients had lower incidence rates of AVF/AVG dysfunction within the first 180 days than non-ADPKD patients, but presented a higher incidence rate after 1 year of AVF/AVG creation and onwards.

A retrospective comparison analysis of results of drug-coated balloon versus plain balloon angioplasty in treatment of juxta-anastomotic de novo stenosis of radiocephalic arteriovenous fistulas

BACKGROUND

Juxta-anastomotic stenosis is a common issue of arteriovenous fistulas. We aimed to evaluate the results of percutaneous transluminal angioplasty with drug-coated balloon versus plain balloon for the treatment of juxta-anastomotic stenoses of mature but failing distal radiocephalic arteriovenous fistulas.

METHODS

A total of 80 patients with a juxta-anastomotic stenosis of distal radiocephalic arteriovenous fistula in our clinic between January 2016 and September 2017 were retrospectively analyzed. Patients were divided into two groups according to the type of treatment as drug-coated balloon - percutaneous transluminal angioplasty (n = 44) and plain balloon - percutaneous transluminal angioplasty (n = 43). Intra- and post-procedural data were recorded. Target lesion primary patency rate was evaluated at 6 and 12 months. Of all patients, 48 were females and 39 were males with a mean age of 56.3 ± 10.4 (range, 24-75) years. Both groups had mature fistulas, and the mean age of fistula was 11.3 ± 9.1 months in the drug-coated balloon - percutaneous transluminal angioplasty group and 10.3 ± 8.8 months in the plain balloon - percutaneous transluminal angioplasty group (p = 0.24).

RESULTS

There was no significant difference in the target lesion stenosis rate and the median lesion length between the groups. Technical and clinical success were achieved in both groups. Target lesion primary patency was similar at 6 months between the two groups (93.1% vs 81.3%, respectively; p = 0.14) but significantly higher for the drug-coated balloon - percutaneous transluminal angioplasty group at 12 months (81.8% vs 51.1%, respectively; p = 0.01).

CONCLUSION

Our study results suggest that the use of drug-coated balloon combined with percutaneous transluminal angioplasty is an effective treatment for juxta-anastomotic stenoses of mature but failing distal radiocephalic arteriovenous fistulas with significantly improved target lesion primary patency rates and reduced need for juxta-anastomotic reinterventions.

Surgeon Characteristics and Dialysis Vascular Access Outcomes in the United States: A Retrospective Cohort Study

RATIONALE & OBJECTIVE

An arteriovenous fistula (AVF) is the preferred access for most patients receiving maintenance hemodialysis, but maturation failure remains a challenge. Surgeon characteristics have been proposed as contributors to AVF success. We examined variation in AVF placement and AVF outcomes by surgeon and surgeon characteristics.

STUDY DESIGN

Retrospective cohort study.

SETTING & PARTICIPANTS

National Medicare claims and web-based data submitted by dialysis facilities on maintenance hemodialysis patients from 2009 through 2015.

EXPOSURES

Patient characteristics, including demographics and comorbid conditions; surgeon characteristics, including specialty, prior volume of AVF placements, and years since medical school graduation.

OUTCOMES

Percent of access placements that were an AVF from 2009 to 2015 (designated AVF placement), and percent of AVFs with successful use within 6 months of placement (maturation) from 2013 to 2014.

ANALYTICAL APPROACH

Multilevel logistic regression models examining the association of surgeon characteristics with the outcomes, adjusted for patient characteristics and dialysis facilities as random effects.

RESULTS

Among 4,959 surgeons placing 467,827 accesses, median AVF placement was 71% (IQR, 59%-84%). More recent year of medical school graduation and general surgery specialty (vs vascular, cardiothoracic, or transplantation surgery) were associated with higher odds of AVF placement. Among 2,770 surgeons placing 49,826 AVFs, the median AVF maturation rate was 59% (IQR, 44%-71%). More recent year of medical school graduation, but not surgical specialty, was associated with higher odds of AVF maturation. Greater prior volume of AVF placement was associated with higher odds of AVF maturation: OR of 1.46 (95% CI, 1.37-1.57) for highest (>84 AVF placements in 2years) versus lowest (<14) volume quintile.

LIMITATIONS

The study relied on administrative data, limiting capture of some factors affecting access outcomes.

CONCLUSIONS

There is substantial surgeon-level variation in AVF placements and AVF maturation. Surgeons' prior volume of AVF placements is strongly associated with AVF maturation.

Jury verdicts and outcomes of malpractice cases involving arteriovenous hemodialysis access

OBJECTIVE

To analyze malpractice cases involving hemodialysis access to prevent future litigation and improve physician education.

METHODS

Jury verdict reviews from the WESTLAW database from 1 January 2005 to 1 January 2015 were reviewed. The search terms "hemodialysis," "dialysis," "graft," "fistula," "AVG," "AVF," "arteriovenous," "catheter," "permacatheter," and "shiley" were used to compile data on the demographics of the defendant, plaintiff, allegation, complication, and verdict.

RESULTS

Sixty-six cases involving the litigation pertaining to hemodialysis catheter, arteriovenous fistula (AVF) or arteriovenous grafts (AVGs) were obtained. Of these, 55% involved catheter-based hemodialysis access, 18% involved AVF, and 27% involved AVG. The most frequent physician defendants were vascular surgeons (36%), internists (14%), nephrologists (14%), general surgeons (9%), and interventional radiologists (6%). Of the patients, 38% involved were male and the average patient age was 56.3 (standard deviation (SD) = 20.1) years. Region of injury was 50% in the neck or chest, 42% in the arm, and 8% in the groin. Injury was listed as death in 79% of cases. Of the deaths, 95% involved bleeding at some point in the chain of events. The most common claims related to the cases were failure to perform the surgery or procedure safely (44%), failure to diagnose and treat in a timely manner (30%), and negligent hemodialysis treatment (11%). The most common complications cited were hemorrhage (62%), loss of function of limb (15%), and ischemia due to steal syndrome (11%). A total of 26 cases (39%) were found for the plaintiff or settled. The median award was US$463,000 with a mean of US$985,299 (SD = US$1,314,557).

CONCLUSION

While popular opinion may indicate that steal syndrome is a commonly litigated complication, our data reveal that the most common injury litigated is death which may frequently be the result of a hemorrhagic episode. In addition to hemorrhage, the remaining most common complications included steal syndrome and loss of limb function. Therefore, steps to better prevent, diagnose and treat bleeding, nerve injury, and steal syndrome in a timely manner are critical to preventing hemodialysis-access-associated litigation.

Factors affecting arteriovenous fistula dysfunction: A narrative review

Vascular access dysfunction is one of the most important causes of morbidity and mortality in haemodialysis patients, contributing to up to one third of hospitalisations and accounting for a significant amount of the health care costs of these patients. In the past decades, significant scientific advances in understanding mechanisms of arteriovenous fistula maturation and failure have contributed to an increase in the amount of research into techniques for creation and strategies for arteriovenous fistula dysfunction prevention and treatment, in order to improve patient care and outcomes. The aim of this review is to describe the pathogenesis of vascular access failure and provide a comprehensive analysis of the associated risk factors and causes of vascular access failure, in order to interpret possible future therapeutic approaches. Arteriovenous fistula failure is a multifactorial process resulting from the combination of upstream and downstream events with consequent venous neo-intimal hyperplasia and/or inadequate outward remodelling. Inflammation appears to be central in the biology of arteriovenous fistula dysfunction but important triggers still need to be revealed. Given the significant association of arteriovenous fistula failure and patient's prognosis, it is therefore imperative to further research in this area in order to improve prevention, surveillance and treatment, and ultimately patient care and outcomes.

Relevance of a skilled vascular surgeon and optimized facility practices in the long-term patency of arteriovenous fistulas: a prospective study

Introduction:

Arteriovenous fistulas (AVF) are the best hemodialysis vascular accesses, but their failure rate remains high. Few studies have addressed the role of the vascular surgeon's skills and the facility's practices. We aimed to study these factors, with the hypothesis that the surgeon's skills and facility practices would have an important role in primary failure and patency rates at 12 months, respectively.

Methods:

This was a single-center, prospective cohort study carried out from March 2005 to March 2017. Only incident patients were included. A single surgeon made all AVFs, either in the forearm (lower) or the elbow (upper). Vascular access definitions were in accordance with the North American Vascular Access Consortium.

Results:

We studied 113 AVFs (65% lower) from 106 patients (39% diabetics, 58% started with catheter). Time to first connection was 21.5 days (IR: 14 - 31). Only 14 AVFs (12.4%) underwent primary failure and 18 failed during the first year. Functional primary patency rate was 80.9% (SE 4.1) whereas primary unassisted patency rate, which included PF, was 70.6% (4.4). Logistic regression showed that diabetes (OR = 3.3, 95%CI 1.38 - 7.88, p = .007) and forearm location (OR = 3.03, 95CI% 1.05 - 8.76, p = 0.04) were predictors of AVF failure. Patency of lower and upper AVFs was similar in non-diabetics, while patency in diabetics with lower AVFs was under 50%. (p = 0.003).

Conclusions:

Results suggest that a long-lasting, suitable AVF is feasible in almost all patients. The surgeon's skills and facility practices can have an important role in the long term outcome of AVF.

A modular vascular access training program for higher surgical trainees

INTRODUCTION

Access surgery is delivered by vascular/transplant surgeons with a division that is defined by historic practice. This has resulted in an inconsistent training pattern. We aimed to design a focused, modular training program (The Brighton Vascular Access Fellowship) providing trainees with a reproducible level of exposure and competence.

METHODS

The programme was 16 days over 8 weeks on a one-to-one basis with candidates expected to be performing procedures as first surgeon with ongoing, formative assessment. The outpatient setting took the format of a one-stop clinic to involve planning and the follow-up. Assessment was through caseload exposure and conventional statistical analyses to obtain median values (as proxy measures of training exposure consistency). Assessment of confidence and capability was through an electronically distributed qualitative survey tool.

RESULTS

A total of 14 candidates completed the programme by June 2017. Operative exposure was obtained for 11 (79%) with a total of 471 cases of which 286 were conducted as first surgeon. There was a median of 32 cases by each candidate with 25 of the cases performed as first surgeon. Qualitative assessment revealed that 13 of 14 (93%) were either practicing independently or no longer required the trainer to scrub in for the operation. A total of 13 of 14 (93%) strongly agreed that they felt comfortable with offering a basic access service.

CONCLUSIONS

Focused modular training might be one of the answers to the current era of restricted and sometimes inconsistent training in some aspects of surgery. This model is reproducible and may be applicable in other aspects of training.

Arteriovenous Fistula Maturation in Prevalent Hemodialysis Patients in the United States: A National Study

BACKGROUND

Arteriovenous fistulas (AVFs) are the preferred form of hemodialysis vascular access, but maturation failures occur frequently, often resulting in prolonged catheter use. We sought to characterize AVF maturation in a national sample of prevalent hemodialysis patients in the United States.

STUDY DESIGN

Nonconcurrent observational cohort study.

SETTING & PARTICIPANTS

Prevalent hemodialysis patients having had at least 1 new AVF placed during 2013, as identified using Medicare claims data in the US Renal Data System.

PREDICTORS

Demographics, geographic location, dialysis vintage, comorbid conditions.

OUTCOMES

Successful maturation following placement defined by subsequent use identified using monthly CROWNWeb data.

MEASUREMENTS

AVF maturation rates were compared across strata of predictors. Patients were followed up until the earliest evidence of death, AVF maturation, or the end of 2014.

RESULTS

In the study period, 45,087 new AVFs were placed in 39,820 prevalent hemodialysis patients. No evidence of use was identified for 36.2% of AVFs. Only 54.7% of AVFs were used within 4 months of placement, with maturation rates varying considerably across end-stage renal disease (ESRD) networks. Older age was associated with lower AVF maturation rates. Female sex, black race, some comorbid conditions (cardiovascular disease, peripheral artery disease, diabetes, needing assistance, or institutionalized status), dialysis vintage longer than 1 year, and catheter or arteriovenous graft use at ESRD incidence were also associated with lower rates of successful AVF maturation. In contrast, hypertension and prior AVF placement at ESRD incidence were associated with higher rates of successful AVF maturation.

LIMITATIONS

This study relies on administrative data, with monthly recording of access use.

CONCLUSIONS

We identified numerous associations between AVF maturation and patient-level factors in a recent national sample of US hemodialysis patients. After accounting for these patient factors, we observed substantial differences in AVF maturation across some ESRD networks, indicating a need for additional study of the provider, practice, and regional factors that explain AVF maturation.

Training vascular access surgeons: technicians or specialists?

Internationally, vascular access (VA) surgery is delivered in a varied and diverse fashion and subsequently, training in vascular access is poorly defined. Experience of VA during surgical training has implications on future practice. The scope of VA procedures is increasing, yet the focus in vascular training remains largely in the technical aspects of surgery rather than the more comprehensive aspects of surgery applied to dialysis and renal care. To achieve special skills in vascular access surgery may require a change to traditional training with an additional focus on developing an extended portfolio of knowledge and skills. A small number of specialized courses and training facilities are developing to address these issues.

The Burden of Tunneled Central Venous Catheters for Hemodialysis in a County Hospital

Prolonged use of central venous catheters (CVCs) for hemodialysis (HD) is associated with greater morbidity and mortality when compared with autogenous arteriovenous fistulas (AVF). The objective was to assess compliance with CVC guidelines in adults referred for hemoaccess at a county teaching hospital. Out of 256 patients, 172 (67.2%) were male, with a mean age of 50.0 ± 12.4 years. Overall 62.5 per cent initiated dialysis via CVC. Patients were divided into two groups (those with CVC (62.5%) and those without (37.5%)). Male gender was associated with initiation of dialysis via CVC versus no CVC (72.5 vs 58.3%, P = 0.02), as was a history of prior vascular access (P < 0.01). There were no significant differences between the groups regarding age, diabetes, smoking, ambulatory status, or insurance status. There were no differences in gender, age, insurance status, or prior vascular access between prolonged CVC use (≥90 days) and short-term CVC use (<90 days). We conclude that most patients initiated HD with CVC and exceed the recommended CVC duration. Men are more likely to initiate HD via CVC. Insurance status was not associated with CVC use. Multidisciplinary action may address barriers to reducing CVC duration.

Intradialytic Ultrafiltration Volume and Vascular Access Outcomes: A Japan Dialysis Outcomes and Practice Patterns Study Subanalysis

Introduction

The relationship between intradialytic ultrafiltration volume and vascular access (VA) patency remains unclear. Using data from the Japan Dialysis Outcomes and Practice Patterns Study, we analyzed whether large-volume ultrafiltration was associated with VA failure in hemodialysis patients.

Methods

We included 2736 patients for whom it was possible to evaluate VA patency and bodyweight change during dialysis. Patients were divided into three groups according to the tertile of intradialytic ultrafiltration by bodyweight: low, -9.5%-3.8%; middle, 3.8%-5.1%; and high, 5.1%-13.7%. Primary VA patency was defined as the time to first VA intervention, and secondary patency as the time to creation of a new VA. Hazard ratios for VA failure were compared across groups by using Cox regression models adjusted for age, sex, body mass index, diabetes, hemoglobin and phosphorus levels, Kt/V, and erythropoiesis-stimulating agent and antiplatelet use.

Results

For the low, middle, and high groups, the incidences of primary and secondary VA patency were 4.7, 5.6, and 6.7 events/100 person-years and 1.3, 1.6, and 1.7 events/100 person-years, respectively. Adjusted hazard ratios for primary VA patency in the middle and high groups versus the low group were 1.16 (95% confidence interval [CI], 0.88-1.52) and 1.41 (95% CI, 1.07-1.87), respectively; those for secondary VA patency were 1.29 (95% CI, 0.78-2.13) and 1.45 (95% CI, 0.86-2.45), respectively.

Discussion

Large-volume ultrafiltration during dialysis tended to increase VA failure in hemodialysis patients. We thus recommend smaller ultrafiltration volumes during hemodialysis to secure VA safely.

Pre-Access Creation Evaluation--Is Vein Mapping Enough?

The changing demographic of the hemodialysis population in the United States is posing significant challenge for selection and creation of an optimal vascular access. An arteriovenous fistula (AVF) is by far the most reliable access provided it matures and functions successfully. System-wide changes implemented by Fistula First Breakthrough Initiative and Kidney Disease Outcomes Quality Initiative guidelines have increased the awareness and incidence of AVF in the prevalent dialysis population; however, achieving the current goal of 68% AVF rate continues to remain elusive. The present article reviews the evidence in literature in support of and against using vessel mapping alone as a strategy to improve AVF rate. The current strategy of evaluating the vessels before an access is created seems to be inadequate. A patient-centered approach for an optimal vascular access needs to be considered to improve the AVF rate.

Arteriovenous Fistula Creation by Nephrologist Access Surgeons Worldwide

Several years ago, we published an article in this journal entitled "Autologous Arteriovenous Fistula Creation by Nephrologists." The goal of that effort was to review outcomes published by nephrologist access surgeons from around the world. An attempt was also made to define the elements that were necessary for successful autologous fistula creation in hopes that they might be used by others in an effort to increase the number of and durability of autologous fistulas in the dialysis population. Our goal, here, is to update the previous information based on recently published literature to better understand the role that nephrologist access surgeons play in the care of our dialysis patients worldwide.

Risk Evaluation of Immediate Surgical Failure During Thigh Hemodialysis Graft Placement by Sonographic Screening

OBJECTIVES

The purpose of this study was to determine whether preoperative sonographic evaluation of vascular diameters and calcification identifies patients at risk for immediate technical failure of thigh hemodialysis grafts.

METHODS

A retrospective analysis of 143 chronic hemodialysis patients who underwent thigh graft placement was performed. All patients underwent preoperative sonography to assess arterial and venous waveforms and vascular diameters. The degree of arterial calcification was assessed retrospectively. Patient characteristics and graft outcomes were examined. Statistical analyses were performed, with P< .05 considered clinically significant.

RESULTS

Sonography identified no or mild arterial calcification in 113 of 143 patients (79%) and moderate to severe calcification in 30 of 143 patients (21%). Primary surgical technical failure occurred in 23% of patients (7 of 30) with moderate to severe calcification, compared to 3.5% (4 of 113) of those with no or mild calcification (hazard ratio, 6.59; 95% confidence interval, 2.06-21.05; P = .002). Cumulative graft survival (time to permanent failure) was shorter in patients with moderate to severe arterial calcification (3-year graft survival, 37% versus 56%; hazard ratio, 2.32; 95% confidence interval, 1.48-6.69; P= .003) but was not significantly associated with venous (P= .82) or arterial (P = .43) diameters.

CONCLUSIONS

Preoperative sonographic assessment of thigh vessel diameters and calcification can identify patients who may be at risk for immediate technical graft failure and decreased cumulative graft survival. The use of sonography as a screening examination may improve preoperative assessment and surgical planning of hemodialysis thigh grafts.

Preserving arteriovenous fistula outcomes during surgical training

PURPOSE

Arteriovenous fistulae (AVFs) are the preferred option for vascular access, as they are associated with lower mortality in hemodialysis patients than in those patients with arteriovenous grafts (AVGs) or central venous catheters (CVCs). We sought to assess whether vascular access outcomes for surgical trainees are comparable to fully trained surgeons.

METHODS

A prospectively collected database of patients was created and information recorded regarding patient demographics, past medical history, preoperative investigations, grade of operating surgeon, type of AVF formed, primary AVF function, cumulative AVF survival and functional patency.

RESULTS

One hundred and sixty-two patients were identified as having had vascular access procedures during the 6 month study period and 143 were included in the final analysis. Secondary AVF patency was established in 123 (86%) of these AVFs and 89 (62.2%) were used for dialysis. There was no significant difference in survival of AVFs according to training status of surgeon (log rank x2 0.506 p=0.477) or type of AVF (log rank x2 0.341 p=0.559). Patency rates of successful AVFs at 1 and 2 years were 60.9% and 47.9%, respectively.

CONCLUSION

We have demonstrated in this prospective study that there are no significant differences in outcomes of primary AVFs formed by fully trained surgeons versus surgical trainees. Creation of a primary AVF represents an excellent training platform for intermediate stage surgeons across general and vascular surgical specialties.

Fistula eligibility: a work in progress

Effective hemodialysis requires a reliable vascular access. Clinical practice guidelines strongly recommend the fistula as the preferred option followed by arteriovenous (AV) grafts, with central venous catheters being least preferred. Recently, there has been a growing awareness of the limitations of the fistula, its high rate of primary failure and that a fistula may not be appropriate for all patients initiating or on hemodialysis. However, determinates for fistula eligibility have not been clearly defined. The creation and use of a fistula requires the complex integration of patient, biological, and surgical factors, none of which can be easily predicted or planned. There have been several successful initiatives over the last decade addressing patient suitability for AV access, but none have validated defined criteria for fistula eligibility. We discuss these initiatives by addressing: 1) process of care, 2) radiological and nonradiological tests and procedures, and 3) alternative surgical approaches. Careful clinical judgment, appropriate vascular access assessment and placement, and an individualized approach to the risks and benefits will optimize patient health outcomes while minimizing prolonged catheter dependence among hemodialysis patients.

Arterio venous fistula experience at a tertiary care hospital in Pakistan

OBJECTIVE

To evaluate the two year patency rate of functioning arteriovenous fistula.

METHODOLOGY

This prospective case series study was conducted at Department of Urology, Jinnah Postgraduate Medical Centre, Karachi, from 1(st) January 2009 to 31(st) December, 2010. Patients were chosen for CBRC arteriovenous fistula at wrist and patients undergoing other types of vascular access or secondary fistula formation were excluded.

RESULTS

One hundred and eighty two patients underwent arteriovenous fistula formation. The mean ± SD age was 63 ± 13 years and there were 102 (56%) males and 80 (44%) females. 12.6% fistulae failed within first month without dialysis. The primary patency rate was 66.5% at three months and 57.7% at six months. Failing arteriovenous fistula was managed by new arteriovenous fistula in our series. 28.6% patients had redo arteriovenous fistula. This study demonstrated a poor outcome for fistulas in diabetic patients. Fifteen out of 23 (65.2%) who failed primarily were diabetics and out of these diabetics 13 (86.7%) failed in first three months. Infection and burst fistulae were found in nine (4.9%), pseudo aneurysm in 3.2%, fever 4.9%, peri-operative failure 0.55% and burst fistulae 3.2%.

CONCLUSIONS

One-third of radiocephalic fistulas fail within two years. The outcome is worse for women and diabetic patients. This information may be useful in assessing and counseling patients with end-stage renal failure. Arteriovenous fistula is the better and ideal choice for haemodialysis. A Radiocephalic fistula in forearm seems to have better results as comparison to cubital fossa arteriovenous fistula. End to side anastomosis results are better than side to side anastomosis.

Arteriovenous Fistula Creation Using the Optiflow™ Vascular Anastomotic Connector: The Open (Optiflow PatEncy and MaturatioN) Study

Purpose

Arteriovenous fistulas (AVFs) are the preferred form of vascular access for hemodialysis. However, non-maturation and patency are major clinical problems. The Optiflow™ device is an implantable anastomotic connector used to standardize the creation of an AVF. Studies have suggested that the geometry of the anastomosis and experience of the surgeon impact patency and maturation rates. The Optiflow serves as a surgical template whereby the geometry and flow path of the anastomosis are predetermined. This prospective study was intended to evaluate maturation, patency and safety of the Optiflow.

Methods

Forty-one upper arm AVFs were created in 41 end-stage renal disease patients using the Optiflow device at two investigational sites. Patients were followed for 90 days with serial Doppler ultrasounds performed at approximately 14, 42 and 90 days to determine AVF maturation. The primary performance endpoint was unassisted maturation, defined as an outflow vein that was equal to or greater than 5 mm in diameter, and with flow equal to or greater than 500 mL/min without the need for any intervention intended to promote or maintain maturation. The primary safety endpoint was the rate of device-related serious adverse events.

Results

Unassisted maturation rates were 76%, 72% and 68% and unassisted patency rates were 93%, 88% and 78%, at 14, 42 and 90 days, respectively. There were no device-related serious adverse events.

Conclusions

The results suggest that the Optiflow is safe for its intended use and could play an important role in enhancing AVF maturation while standardizing the anastomotic technique.

Objectives and design of the hemodialysis fistula maturation study

BACKGROUND

A large proportion of newly created arteriovenous fistulas cannot be used for dialysis because they fail to mature adequately to support the hemodialysis blood circuit. The Hemodialysis Fistula Maturation (HFM) Study was designed to elucidate clinical and biological factors associated with fistula maturation outcomes.

STUDY DESIGN

Multicenter prospective cohort study.

SETTING & PARTICIPANTS

Approximately 600 patients undergoing creation of a new hemodialysis fistula will be enrolled at 7 centers in the United States and followed up for as long as 4 years.

PREDICTORS

Clinical, anatomical, biological, and process-of-care attributes identified pre-, intra-, or postoperatively.

OUTCOMES

The primary outcome is unassisted clinical maturation, defined as successful use of the fistula for dialysis for 4 weeks without maturation-enhancing procedures. Secondary outcomes include assisted clinical maturation, ultrasound-based anatomical maturation, fistula procedures, fistula abandonment, and central venous catheter use.

MEASUREMENTS

Preoperative ultrasound arterial and venous mapping, flow-mediated and nitroglycerin-mediated brachial artery dilation, arterial pulse wave velocity, and venous distensibility; intraoperative vein tissue collection for histopathologic and molecular analyses; postoperative ultrasounds at 1 day, 2 weeks, 6 weeks, and prior to fistula intervention and initial cannulation.

RESULTS

Assuming complete data, no covariate adjustment, and unassisted clinical maturation of 50%, there will be 80% power to detect ORs of 1.83 and 1.61 for dichotomous predictor variables with exposure prevalences of 20% and 50%, respectively.

LIMITATIONS

Exclusion of 2-stage transposition fistulas limits generalizability. The requirement for study visits may result in a cohort that is healthier than the overall population of patients undergoing fistula creation.

CONCLUSIONS

The HFM Study will be of sufficient size and scope to: (1) evaluate a broad range of mechanistic hypotheses, (2) identify clinical practices associated with maturation outcomes, (3) assess the predictive utility of early indicators of fistula outcome, and (4) establish targets for novel therapeutic interventions to improve fistula maturation.

Temporal risk profile for infectious and noninfectious complications of hemodialysis access

Vascular access complications are a major cause of morbidity in patients undergoing hemodialysis, and determining how the risks of different complications vary over the life of an access may benefit the design of prevention strategies. We used data from the Dialysis Outcomes and Practice Patterns Study (DOPPS) to assess the temporal profiles of risks for infectious and noninfectious complications of fistulas, grafts, and tunneled catheters in incident hemodialysis patients. We used longitudinal data to model time from access placement or successful treatment of a previous complication to subsequent complication and considered multiple accesses per patient and repeated access complications using baseline and time-varying covariates to obtain adjusted estimates. Of the 7769 incident patients identified, 7140 received at least one permanent access. During a median follow-up of 14 months (interquartile range, 7-22 months), 10,452 noninfectious and 1131 infectious events (including 551 hospitalizations for sepsis) occurred in 112,085 patient-months. The hazards for both complication types declined over time in all access types: They were 5-10 times greater in the first 3-6 months than in later periods after access placement or a remedial access-related procedure. The hazards declined more quickly with fistulas than with grafts and catheters (P<0.001; Weibull regression). These data indicate that risks for noninfectious and infectious complications of the hemodialysis access decline over time with all access types and suggest that prevention strategies should target the first 6 months after access placement or a remedial access-related procedure.

Re-envisioning Fistula First in a patient-centered culture

The main options for vascular access in hemodialysis patients are arteriovenous fistulas (AVFs), arteriovenous grafts, and tunneled cuffed central venous catheters. AVFs have the lowest complication rate and require the fewest interventions and lowest cost to maintain. There has been a dramatic national increase in prevalent AVFs among patients with ESRD in the United States driven, in part, by the Fistula First Breakthrough Initiative. The Fistula First Breakthrough Initiative has engaged stakeholders in the dialysis community to disseminate best practices and quality improvement activities to increase AVF prevalence in suitable candidates. In the pursuit of maximizing AVF placement and prevalence, less emphasis has been placed on the individual patient context. An AVF may not be the best access choice in a subset of patients, particularly those with poor long-term prognoses or comorbid chronic diseases with a short life expectancy, those patients more likely to die than to have their CKD progress to ESRD requiring dialysis, and those with vascular anatomy not amenable to successful AVF placement. Placement of an AVF in these patients subjects them to uncomfortable and likely unnecessary and/or unsuccessful surgeries at an expense, while doing little to improve their clinical outcome or their individual experience of care. AVF prevalence as a pay-for-performance measure without the appropriate case-mix adjustment may penalize providers for accepting higher-risk patients. Although a functioning AVF that provides reliable hemodialysis remains the gold standard for vascular access for most patients, it may not be the most suitable option for every patient.

Vascular access and infection prevention and control: a national survey of routine practices in Irish haemodialysis units

BACKGROUND

National and international guidelines recommend the use of effective vascular access (VA) and infection prevention and control practices within the haemodialysis environment. Establishing an arterio-venous fistula (AVF) and preventing central venous catheter (CVC)-related infections are ongoing challenges for all dialysis settings. We surveyed VA and routine infection prevention and control practices in dialysis units, to provide national data on these practices in Ireland.

METHODS

A descriptive survey was emailed to nurse managers at all adult (n = 19) and children (n = 1) outpatient haemodialysis units in the Republic of Ireland. Data collected included AVF formation, CVC insertion and maintenance practices, VA use and surveillance of infection and screening protocols. Nineteen of the 20 units responded to the survey.

RESULTS

The AVF prevalence was 49% for 1370 patients in 17 units who provided these data [mean prevalence per unit: 45.7% (SD 16.2)]; the CVC mean prevalence per unit was 52.5% (SD 16.0). Fourteen dialysis units experienced inadequate access to vascular surgical procedures either due to a lack of dedicated theatre time or hospital beds. Six units administered intravenous prophylactic antimicrobials prior to CVC insertion with only two units using a CVC insertion checklist at the time of catheter insertion.

CONCLUSION

In general, dialysis units in Ireland show a strong adherence to national guidelines. Compared with the 12 countries participating in the Dialysis Outcomes Practice Patterns Study (DOPPS 4), in 2010, AVF prevalence in Irish dialysis units is the second lowest. Recommendations include establishing an AVF national prevalence target rate, discontinuing the administration of intravenous prophylactic antimicrobials prior to CVC insertion and promoting the use of CVC insertion checklists.

Education in vascular access

The successful creation and use of an arteriovenous vascular access (VA) requires a coordinated, educated multidisciplinary team to ensure an optimal VA for each patient. Patient education programs on VA are associated with increased arteriovenous VA use at dialysis initiation. Education should be tailored to patient goals and preferences with the understanding that experiential education from patient to patient is far more influential than that provided by the healthcare professional. VA education for the nephrologist should focus on addressing the systematic and patient-level barriers in achieving a functional VA, with specific components relating to VA creation, maturation, and cannulation that consider patient goals and preferences. A deficit in nursing skills in the area of assessment and cannulation can have devastating consequences for hemodialysis patients. Delivery of an integrated education program increases nurses' knowledge of VA and development of simulation programs or constructs to assist in cannulation of the VA will greatly facilitate the much needed skill transfer. Adequate VA surgical training and experience are critical to the creation and outcomes of VA. Simulations can benefit nephrologists, dialysis nurses surgeons, and interventionalists though aiding in surgical creation, understanding of the physiology and anatomy of a dysfunctional VA, and practicing cannulation techniques. All future educational initiatives must emphasize the importance of multidisciplinary care to attain successful VA outcomes.

Hemodialysis access usage patterns in the incident dialysis year and associated catheter-related complications

BACKGROUND

Hemodialysis (HD) access is considered a critical and actionable determinant of morbidity, with a growing literature suggesting that initial HD access type is an important marker of long-term outcomes. Accordingly, we examined HD access during the incident dialysis period, focusing on infection risk and successful fistula creation during the first dialysis year.

STUDY DESIGN

Longitudinal cohort.

SETTING & PARTICIPANTS

All US adults admitted to Fresenius Medical Care North America facilities within 15 days of first maintenance dialysis session between January 1 and December 31, 2007.

PREDICTOR

Vascular access type at HD therapy initiation.

OUTCOMES

Vascular access type at 90 days and at the end of the first year on HD therapy, bloodstream infection within the first year by access type, and catheter complication rate.

RESULTS

Of 25,003 incident dialysis patients studied, 19,622 (78.5%) initiated dialysis with a catheter; 4,151 (16.6%), with a fistula; and 1,230 (4.9%), with a graft. At 90 days, 14,105 (69.7%) had a catheter, 4,432 (21.9%) had a fistula, and 1,705 (8.4%) had a graft. Functioning fistulas and grafts at dialysis therapy initiation had first-year failure rates of 10% and 15%, respectively. Grafts were seldom replaced by fistulas (3%), whereas 7,064 (47.6%) of all patients who initiated with a catheter alone still had only a catheter at 1 year. Overall, 3,327 (13.3%) patients had at least one positive blood culture during follow-up, with the risk being similar between the fistula and graft groups, but approximately 3-fold higher in patients with a catheter (P<0.001 for either comparison). Nearly 1 in 3 catheters (32.5%) will require tissue plasminogen activator use by a median of 41 days, with 59% requiring more than one tissue plasminogen activator administration.

LIMITATIONS

Potential underestimation of bacteremia because follow-up blood culture results did not include samples sent to local laboratories.

CONCLUSIONS

In a large and representative population of incident US dialysis patients, catheter use remains very high during the first year of HD care and is associated with high mechanical complication and bloodstream infection rates.

Dialysis adequacy today: a European perspective

The need to improve haemodialysis (HD) therapies and to reduce cardiovascular and all-cause mortality frequently encountered by dialysis patients has been recognized and addressed for many years. A number of approaches, including increasing the frequency versus duration of treatment, have been proposed and debated in terms of their clinical efficacy and economic feasibility. Future prescription of dialysis to an expanding end-stage chronic kidney disease (CKD-5D) population needs a re-evaluation of existing practices while maintaining the emphasis on patient well-being both in the short and in the long term. Efficient cleansing of the blood of all relevant uraemic toxins, including fluid and salt overload, remains the fundamental objective of all dialysis therapies. Simultaneously, metabolic disorders (e.g. anaemia, mineral bone disease, oxidative stress) that accompany renal failure need to be corrected also as part of the delivery of dialysis therapy itself. Usage of high-flux membranes that enable small and large uraemic toxins to be eliminated from the blood is the first prerequisite towards the aforementioned goals. Application of convective therapies [(online-haemodiafiltration (OL-HDF)] further enhances the detoxification effects of high-flux haemodialysis (HF-HD). However, despite an extended clinical experience with both HF-HD and OL-HDF spanning more than two decades, a more widespread prescription of convective treatment modalities awaits more conclusive evidence from large-scale prospective randomized controlled trials. In this review, we present a European perspective on the need to implement optimal dialysis and to improve it by adopting high convective therapies and to discuss whether inertia to implement these practice patterns may deprive patients of significantly improved well-being and survival.