Recruitment into randomised trials of arteriovenous grafts: A systematic review

Although randomised controlled trials (RCT) are considered the optimal form of evidence, there are relatively few in surgery. Surgical RCT are particularly likely to be discontinued with poor recruitment cited as a leading reason. Surgical RCT present challenges over and above those seen in drug trials as the treatment under study may vary between procedures, between surgeons in one unit, and between units in multi-centred RCT. The most contentious and debated area of vascular access remains the role of arteriovenous grafts, and thus the quality of the data that is used to support opinions, guidelines and recommendations is critical. The aim of this review was to determine the extent of variation in the planning and recruitment in all RCT involving AVG. The findings of this are stark: there have been only 31 RCT performed in 31 years, the vast majority of which exhibited major limitations severe enough to undermine the results. This underlines the need for better quality RCT and data, and further inform the design of future studies. Perhaps most fundamental is the planning for a RCT that accounts for the intended population, the uptake of a RCT and the attrition for the significant co-morbidity in this population.

Frailty in Kidney Disease: A Comprehensive Review to Advance Its Clinical and Research Applications

Frailty is a multisystem syndrome of decreased physiologic reserve that has been shown to strongly and independently predict morbidity and mortality. Frailty is prevalent in patients living with kidney disease and occurs earlier in individuals with kidney disease as compared to the general population. In this comprehensive review, we examine clinical and research applications of frailty in kidney disease populations. Specifically, we clarify the definition of frailty and address common misconceptions, review the mechanisms and epidemiology of frailty in kidney disease, discuss challenges and limitations in frailty measurement, and provide updated evidence related to risk factors for frailty, its associated adverse outcomes, and interventions. We further add to the literature in this topic by highlighting the potential applications of frailty measurement in the care of patients with kidney disease and conclude with our recommendations for future research related to this important syndrome.

Patients, healthcare providers, and general population preferences for hemodialysis vascular access: a discrete choice experiment

Background

A patient-centered dialysis treatment option requires an understanding of patient preferences for alternative vascular accesses and nephrologists often face difficulties when recommending vascular access to end-stage kidney disease (ESKD) patients. We aimed to quantify the relative importance of various vascular access characteristics to patients, healthcare providers and general population, and how they affect acceptability for patients and healthcare providers.

Methods

In a discrete choice experiment, patients with maintenance hemodialysis (MHD), healthcare providers, and individuals from the general population were invited to respond to a series of hypothetical vascular access scenarios that differed in five attributes: cumulative patency, infection rate, thrombosis rate, cost, and time to maturation. We estimated the respondents' preference heterogeneity and relative importance of the attributes with a mixed logit model (MXL) and predicted the willingness to pay (WTP) of respondents via a multinomial logit model (MNL).

Results

Healthcare providers (n = 316) and the general population (n = 268) exhibited a favorable inclination toward longer cumulative patency, lower access infection rate and lower access thrombosis rate. In contrast, the patients (n = 253) showed a preference for a 3-year cumulative patency, 8% access infection rate, 35% access thrombosis rate and 1.5 access maturity time, with only the 3-year cumulative patency reaching statistical significance. Among the three respondent groups, the general population found cumulative patency less important than healthcare providers and patients did. Patients demonstrated the highest WTP for cumulative patency, indicating a willingness to pay an extra RMB$24,720(US$3,708) for each additional year of patency time.

Conclusion

Patients and healthcare providers had a strong preference for vascular access with superior patency. While the general population preferred vascular access with lower thrombosis rates. These results indicate that most patients prefer autogenous arteriovenous fistula (AVF) as an appropriate choice for vascular access due to its superior patency and lower complications than other vascular access types.

Frailty screening for determination of hemodialysis access placement

OBJECTIVE

Choosing the right hemodialysis vascular access for frail patients remains difficult because the patient's preferences and the likelihood of access function and survival must be considered. We hypothesize that patients identified before arteriovenous (AV) access as frail by the PRISMA-7 score may have worse outcomes, indicating that fistula creation may not be the most clinically beneficial option and it would be in the best interest of the patient to receive either AV graft (AVG) placement or dialysis through a percutaneous catheter. Our pilot study aims to determine whether an association exists between patient frailty as defined by PRISMA-7 and newly created AV fistula (AVF) and AVG access outcomes.

METHODS

This was a single institutional prospective cohort study of patients undergoing new AVF or AVG intervention from April 2021 to May 2023. Patients were assessed using the PRISMA-7 frailty questionnaire before their AV access surgery. Patients were grouped by frailty score and score groups were examined for trends. Univariable analysis was performed for baseline differences between frail and nonfrail patients. Failure to achieve maturation, postoperative infection, and 180-day mortality difference was also investigated for frail vs nonfrail patients. Univariable analysis was performed for nonmaturation using standard comorbidities, arterial and venous diameters, and frailty. Multivariable binary logistic regression was performed for the outcome of nonmaturation using frailty as one of the variables in conjunction with the univariable risks associated with nonmaturation.

RESULTS

A total of 40 patients undergoing new AV access placement were investigated, among whom 53% were designated as frail (PRISMA-7 score ≥3). When comparing the frail and nonfrail new AV access groups, the access (AVF and AVG combined) failed in 48% (10/21) of the frail patients, but only failed in 5% (1/19) of the nonfrail patients 1 (P = .012). When distinguishing between AV access types, AVF creations followed the overall trend with 60% of AVF access (9/15) sites in frail patients failing to mature when compared with nonfrail patients, who all had fistulas that matured to use (P = .049). Surgical site infection was absent in all frail patients and present in 5% of nonfrail patients (1/19). Both 30-day and 60-day readmission rates were higher in the frail group compared with the nonfrail group. There was 180-day mortality present in 5 of frail patients % (1/21) and absent in nonfrail patients. Multivariable analysis revealed that both frailty (adjusted odd ratio, 10.19; 95% confidence interval, 1.20-82.25); P = .033) and younger age (adjusted odd ratio, 0.953; 95% confidence interval, 0.923-0.983; P = .002) both had a significant association with nonmaturation. Power analysis revealed a power statistic of 0.898 indicating a probability of type 2 error of 10.02% with a P value of .002. Hosmer-Lemeshow goodness of fit for the logistic regression had 75% overall accuracy for the model.

CONCLUSIONS

Patient frailty is significantly associated with an increased incidence of AV access failure to mature.

Guidelines on vascular access for hemodialysis from the Brazilian Society of Angiology and Vascular Surgery

Chronic kidney disease is a worldwide public health problem, and end-stage renal disease requires dialysis. Most patients requiring renal replacement therapy have to undergo hemodialysis. Therefore, vascular access is extremely important for the dialysis population, directly affecting the quality of life and the morbidity and mortality of this patient population. Since making, managing and salvaging of vascular accesses falls within the purview of the vascular surgeon, developing guideline to help specialists better manage vascular accesses for hemodialysis if of great importance. Thus, the objective of this guideline is to present a set of recommendations to guide decisions involved in the referral, evaluation, choice, surveillance and management of complications of vascular accesses for hemodialysis.

Study protocol of a randomized controlled trial of fistula vs. graft arteriovenous vascular access in older adults with end-stage kidney disease on hemodialysis: the AV access trial

BACKGROUND

Treatment of end-stage kidney disease (ESKD) with hemodialysis requires surgical creation of an arteriovenous (AV) vascular access-fistula (AVF) or graft (AVG)-to avoid (or limit) the use of a central venous catheter (CVC). AVFs have long been considered the first-line vascular access option, with AVGs as second best. Recent studies have suggested that, in older adults, AVGs may be a better strategy than AVFs. Lacking evidence from well-powered randomized clinical trials, integration of these results into clinical decision making is challenging. The main objective of the AV Access Study is to compare, between the two types of AV access, clinical outcomes that are important to patients, physicians, and policy makers.

METHODS

This is a prospective, multicenter, randomized controlled trial in adults ≥ 60 years old receiving chronic hemodialysis via a CVC. Eligible participants must have co-existing cardiovascular disease, peripheral arterial disease, and/or diabetes mellitus; and vascular anatomy suitable for placement of either type of AV access. Participants are randomized, in a 1:1 ratio, to a strategy of AVG or AVF creation. An estimated 262 participants will be recruited across 7 healthcare systems, with average follow-up of 2 years. Questionnaires will be administered at baseline and semi-annually. The primary outcome is the rate of CVC-free days per 100 patient-days. The primary safety outcome is the cumulative incidence of vascular access (CVC or AV access)-related severe infections-defined as access infections that lead to hospitalization or death. Secondary outcomes include access-related healthcare costs and patients' experiences with vascular access care between the two treatment groups.

DISCUSSION

In the absence of studies using robust and unbiased research methodology to address vascular access care for hemodialysis patients, clinical decisions are limited to inferences from observational studies. The goal of the AV Access Study is to generate evidence to optimize vascular access care, based on objective, age-specific criteria, while incorporating goals of care and patient preference for vascular access type in clinical decision-making.

TRIAL REGISTRATION

This study is being conducted in accordance with the tenets of the Helsinki Declaration, and has been approved by the central institutional review board (IRB) of Wake Forest University Health Sciences (approval number: 00069593) and local IRB of each participating clinical center; and was registered on Nov 27, 2020, at ClinicalTrials.gov (NCT04646226).

Differential hemodynamics between arteriovenous fistulas with or without intervention before successful use

A significant number of arteriovenous fistulas (AVFs) fail to maturate for dialysis. Although interventions promote maturation, functional primary patency loss is higher for AVFs with interventions (assisted maturation) than AVFs without interventions (un-assisted maturation). Although blood flow-associated hemodynamics have long been proposed to affect AVF remodeling, the optimal hemodynamic parameters for un-assisted maturation are unclear. Additionally, AVF maturation progress is generally not investigated until 6 weeks after AVF creation, and the examination is focused on the AVF's venous limb. In this exploratory study, patients (n = 6) underwent magnetic resonance imaging (MRI) at 1 day, 6 weeks, and 6 months after AVF creation surgery. Before successful use for hemodialysis, three AVFs required intervention and three did not. MRI of the AVFs were used to calculate lumen cross-sectional area (CSA) and perform computational fluid dynamics (CFD) to analyze hemodynamics, including velocity, wall shear stress (WSS), and vorticity. For the venous limb, the no-intervention group and intervention group had similar pre-surgery vein diameter and 1-day post-surgery venous CSA. However, the no-intervention group had statistically larger 1-day venous velocity (0.97 ± 0.67 m/s; mean ± SD), WSS (333 ± 336 dyne/cm2) and vorticity (1709 ± 1290 1/s) than the intervention group (velocity = 0.23 ± 0.10 m/s; WSS = 49 ± 40 dyne/cm2; vorticity = 493.1 ± 227 1/s) (P < 0.05). At 6 months, the no-intervention group had statistically larger venous CSA (43.5 ± 27.4 mm2) than the intervention group (15.1 ± 6.2 mm2) (P < 0.05). Regarding the arterial limb, no-intervention AVF arteries also had statistically larger 1-day velocity (1.17 ± 1.0 m/s), WSS (340 ± 423 dyne/cm2), vorticity (1787 ± 1694 1/s), and 6-month CSA (22.6 ± 22.7 mm2) than the intervention group (velocity = 0.64 ± 0.36 m/s; WSS = 104 ± 116 dyne/cm2, P < 0.05; vorticity = 867 ± 4551/s; CSA = 10.7 ± 6.0 mm2, P < 0.05). Larger venous velocity, WSS, and vorticity immediately after AVF creation surgery may be important for later lumen enlargement and AVF maturation, with the potential to be used as a tool to help diagnose poor AVF maturation earlier. However, future studies using a larger cohort are needed to validate this finding and determine cut off values, if any.

Shared decision-making in hemodialysis vascular access practice

Shared decision-making (SDM) is a process of collaborative deliberation in the dyadic patient-physician interaction whereby physicians inform the patients about the pros and cons of all available treatment options and reach an agreement with the patients on their preferred treatment plan. In hemodialysis vascular access practice, SDM advocates a deliberative approach based on the existence of reasonable alternatives-that is, arteriovenous fistula, arteriovenous graft, and central venous catheter-so that patients are able to form and share preferences about access options. In spite of its ethical imperative, SDM is not broadly applied in hemodialysis vascular access planning. Physicians and surgeons commonly deliver prescriptive fistula-centered recommendations concerning the approach to vascular access care. This paternalistic approach has been shaped by directions from long-held clinical practice guidelines and is reinforced by financial payment models linked with the prevalence of arteriovenous fistula in patients on hemodialysis. Awareness is growing that what may have initially seemed a medically and surgically appropriate approach might not always be focused on each individual's goals of care. Clinician's recommendations for vascular access often do not sufficiently consider the uncertainty surrounding the potential benefits of the decision or the cumulative impact of the decision on patient's quality of life. In the evolving health care landscape, it is time for the practice of hemodialysis vascular access to shift from a hierarchical doctor-patient approach to patient-centered care. In this article we review the current state of vascular access practice, present arguments why SDM is necessary in vascular access planning, review barriers and potential solutions to SDM implementation, and discuss future research contingent on an effective system of physician-patient participative decision-making in hemodialysis vascular access practice.

New Frontiers in Vascular Access Practice: From Standardized to Patient-tailored Care and Shared Decision Making

Vascular access planning is critical in the management of patients with advanced kidney disease who elect for hemodialysis for RRT. Policies put in place more than two decades ago attempted to standardize vascular access care around the model of optimal, namely arteriovenous fistula, and least preferred, namely central venous catheter, type of access. This homogenized approach to vascular access care emerged ineffective in the increasingly heterogeneous and complex dialysis population. The most recent vascular access guidelines acknowledge the limitations of standardized care and encourage tailoring vascular access care on the basis of patient and disease characteristics. In this article, we discuss available literature in support of patient-tailored access care on the basis of differences in vascular access outcomes by biologic and social factors-age, sex, and race. Further, we draw attention to the overlooked dimension of patient-reported preferences and shared decision making in the practice of vascular access planning. We discuss milestones to overcome as requisite steps to implement effective shared decision making in vascular access care. Finally, we take into consideration local practice cofactors as major players in vascular access fate. We conclude that a personalized approach to hemodialysis vascular access will require dynamic care specifically relevant to the individual on the basis of biologic factors, fluctuating clinical needs, values, and preferences.

Long-term patency and comparisons of venous outflow in hemodialysis forearm arteriovenous grafts

INTRODUCTION

This retrospective study investigated the factors and the effects of different venous outflows on forearm arteriovenous graft patency.

METHODS

The venous outflow sites included basilic, cephalic, median antecubital, and deep veins. Comparisons among multiple groups were analyzed.

FINDINGS

A total of 179 patients with forearm loop arteriovenous grafts met the inclusion criteria. Of these, 72 were basilic, 48 were cephalic, 44 were median antecubital, and 15 were deep. The median observation period was 19 months. The survival rate was 84.9% at 24 months and 78.2% at 48 months. Primary, secondary, and assisted primary patency rates for all arteriovenous grafts were 48.9%, 72.4%, and 68.4% at 12 months; 13.8%, 33.9%, and 23.6% at 24 months; and 0.6%, 4.6%, and 2.3% at 48 months, respectively. Differences in primary patency were statistically significant compared with those of secondary and assisted primary patency (P < 0.05). Primary patency rates for cephalic, median antecubital, basilic, and deep were 47.9%, 48.6%, 47.7%, and 40.0% at 12 months and 12.5%, 13.9%, 22.7%, and 0% at 24 months, respectively. Secondary patency rates for cephalic, median antecubital, basilic, and deep were 75.0%, 69.4%, 75.0%, and 73.3% at 12 months and 39.6%, 30.6%, 38.6%, and 13.3% at 24 months, respectively. There was no significant difference in primary thrombosis among basilic, cephalic, median antecubital and deep. There were no significant differences observed in primary or secondary patency rates among all the groups. Stenoses in the venous anastomosis and outflow vein were frequently observed in all types of arteriovenous grafts. Central venous stenosis was most commonly seen in deep (26.67%). On average, 1.9 interventions per patient were performed on the graft to maintain function.

CONCLUSION

Different venous outflow selections were not associated with long-term patency and the occurrence of thrombosis in hemodialysis forearm loop arteriovenous grafts.

Long-Term Outcomes of the Flixene Vascular Graft Used for Haemodialysis

Introduction

The Flixene™ vascular graft (Maquet-Atrium Medical, Hudson, NH) has emerged as a new generation synthetic graft, which allows for early needling for haemodialysis. Most studies have shown satisfactory early results. The aim of this study is to report on long-term outcomes of the Flixene graft over eight years in a cohort of patients.

Methods

From February 2011 to September 2019, 61 patients had 64 arteriovenous graft fistulas (AVGs) by using the Flixene grafts. The median patient age was 67 years; the male to female ratio was 30:31. Diabetes was the reason for the majority of kidney failures (57%). The configuration of the grafts used was mostly upper arm straight AVG. The primary patency rate, secondary patency rate, and surgical complications were assessed.

Results

In a median follow-up of three years (interquartile range (IQR): 2 - 6), 36 of the AVGs required a fistulogram. Venous side stenosis was the most common cause of high venous pressure or AVG occlusion in 97%. The one-year primary patency rate was 30%. The secondary patency rate was 94.8%, 83.7%, and 77.7% at one, three, and five years, respectively. The longest functional AVG was observed for up to seven years.

Conclusions

This study has shown satisfactory long-term results of the Flixene graft used for hemodialysis. The Flixene graft could be needled within 72 hours without increased complications, which allows the creation of an AVG under an emergency setting to avoid the placement of a central venous catheter (CVC). This strategy should be advocated in future clinical practice.

Single Asian Center Experience Using the Flixene™ Early Cannulation Graft for Hemodialysis Access Creation

BACKGROUND

The aim of this study was to review the efficacy of the Flixene™ (Atrium™, Hudson, NH, USA) hemodialysis arterio-venous graft (AVG) in a multiethnic Asian cohort of patients with end-stage renal failure (ESRF). Primary outcome was graft primary patency rate and secondary end points included graft usability, time to cannulation, reinterventions required for access salvage, complications, and patient mortality.

METHODS

Single-center, single-arm, multi-investigator nonrandomized retrospective study. Patients with ESRF who underwent Flixene™ graft implantation over a two-year period (January 2017 - December 2018) were included to allow at least one-year follow-up. Demographics, procedural and follow-up data were collected from the hospital electronic medical records.

RESULTS

About 48 patients (49 AVG) were included. There were 24 (50%) men; mean age 63.7 (IQR 58.2-71.3) years. Technical success rate was 45/49 (91.8%); 4/49 (8.2%) AVG created did not reach cannulation. 11/49 (22.4%) and 28/49 (57.1%) achieved cannulation within 1 and 2 weeks, respectively. 6- and 12- month primary patencies were 33.5% and 19.6%, respectively. Primary-assisted patency rates were 46.6% and 29.6% at the same time intervals. Secondary patency rate was 77.6% and 63.9% at 6 and 12 months, respectively. There were 6 (12.2%) graft infections requiring explant and one-year mortality was 14%.

CONCLUSIONS

Our experience with the Flixene™ early cannulation graft is comparable with other AVGs in terms of patency and infection rates. However, early cannulation rates are lower than in other case series.

A systematic review of the brachial vein arteriovenous fistulas as a viable option for haemodialysis access

OBJECTIVES

International guidelines recommend the use of autogenous vascular access. Where suitable superficial veins are unavailable deeper veins may be used as an option. In most cases, basilic veins are used when cephalic veins are unavailable; arteriovenous fistulas using the brachial vein from the deep venous network are rare. Therefore, the purpose of the present study was to conduct a systematic review of the available literature evaluating the use of the brachial vein in arteriovenous fistulas.

METHODS

Systematic literature search of electronic databases in accordance with PRISMA was conducted. The primary outcomes of this study were primary and secondary patency rates for brachial vein arteriovenous fistulas; the secondary outcomes were the rates of access thrombosis, steal syndrome, pseudo-aneurysm and infection.

RESULTS

The 1-year primary, assisted, and secondary patency was recorded at (24%-77%), (45%-85%) and (45%-96%), respectively. The 2-year primary, assisted and secondary patency rate was recorded at (12%-46%), (19%-75%) and (19%-92%), respectively. However, the consistency regarding the reports and definitions used were highly variable. The incidence rate of infection, thrombosis and steal syndrome was 5% (0%-12%), 15.9% (9.5%-35%) and 3% (2%-6%), respectively.

CONCLUSION

Available studies support the use of brachial veins as a reliable access option in patients with non-accessible superficial veins where an autologous option is required.

Challenges and novel therapies for vascular access in haemodialysis

Advances in standards of care have extended the life expectancy of patients with kidney failure. However, options for chronic vascular access for haemodialysis - an essential part of kidney replacement therapy - have remained unchanged for decades. The high morbidity and mortality associated with current vascular access complications highlights an unmet clinical need for novel techniques in vascular access and is driving innovation in vascular access care. The development of devices, biological approaches and novel access techniques has led to new approaches to controlling fistula geometry and manipulating the underlying cellular and molecular pathways of the vascular endothelium, and influencing fistula maturation and formation through the use of external mechanical methods. Innovations in arteriovenous graft materials range from small modifications to the graft lumen to the creation of completely novel bioengineered grafts. Steps have even been taken to create new devices for the treatment of patients with central vein stenosis. However, these emerging therapies face difficult hurdles, and truly creative approaches to vascular access need resources that include well-designed clinical trials, frequent interaction with regulators, interventionalist education and sufficient funding. In addition, the heterogeneity of patients with kidney failure suggests it is unlikely that a 'one-size-fits-all' approach for effective vascular access will be feasible in the current environment.

Vascular access placement and mortality in elderly incident hemodialysis patients

BACKGROUND

Arteriovenous fistulas (AVFs) are the preferred vascular access type in most hemodialysis patients. However, the optimal vascular access type in octogenarians and older (≥80 years) hemodialysis patients remains widely debated given their limited life expectancy and lower AVF maturation rates.

METHODS

Among incident hemodialysis patients receiving care in a large national dialysis organization during 2007-2011, we examined patterns of vascular access type conversion in 1 year following dialysis initiation in patients <80 versus ≥80 years of age. Among a subcohort of patients ≥80 years of age, we examined the association between vascular access type conversion and mortality using multivariable survival models.

RESULTS

In the overall cohort of 100 804 patients, the prevalence of AVF/arteriovenous graft (AVG) as the primary vascular access type increased during the first year of hemodialysis, but plateaued thereafter. Among 8356 patients ≥80 years of age and treated for >1 year, those with initial AVF/AVG use and placement of AVF from a central venous catheter (CVC) had lower mortality compared with patients with persistent CVC use. When the reference group was changed to patients who had AVF placement from a CVC in the first year of dialysis, those with initial AVF use had similar mortality. A longer duration of CVC use was associated with incrementally worse survival.

CONCLUSIONS

Among incident hemodialysis patients ≥80 years of age, placement of an AVF from a CVC within the first year of dialysis had similar mortality compared with initial AVF use. Our data suggest that initial CVC use with later placement of an AVF may be an acceptable option among elderly hemodialysis patients.

Quality indicators of vascular access procedures for hemodialysis

Improved quality of surgical procedures can minimize complications, the morbidity and mortality of patients, and in addition decrease costs. Quality indicators in angioaccess surgery are, however, not clearly defined. The aim of this review article is therefore to find the most important factors affecting quality in vascular access procedures. Even though autogenous arteriovenous fistula has been recognized as the best vascular access for hemodialysis, the high percentage of unsuccessful attempts associated with it raises the question about quality assessment in angioaccess procedures. Unfortunately, quality indicators in vascular access surgery are difficult to define and measure. Among those that can be obtained are: the time between the presentation of patients to a vascular access surgeon and the construction of a fistula, the percentage of autogenous fistulas, the percentage of functional fistulas in prevalent and incident hemodialysis patients, the percentage of creation of a functional fistula in the first attempt, and durability of an access. Organizational improvement and educational programs are also necessary at institutions with inferior quality indicators of vascular access care, as even small increase in quality may mean the survival of an individual patient. Quality indicators in angioaccess surgery can also serve as a helpful tool in choosing the best vascular access surgeon or vascular access center. The choice can consequently reflect on increased survival and quality of life in patients needing hemodialysis.

The Role of Far Infrared Therapy in the Unassisted Maturation of Arterio-venous Fistula in Patients with Chronic Kidney Disease

Introduction:

The goal of arterio-venous fistula (AVF) creation is to achieve a well-functioning access that can be cannulated repetitively and can provide adequate flow for the dialysis. The objective of this study was to assess the role of far infrared (FIR) therapy in the unassisted maturation of newly created AVF in patients with chronic kidney disease (CKD).

Materials and Methods:

In this prospective open labeled randomised control trial, 107 patients were randomized. Participants in the control arm received oral clopidogrel 75 mg once daily for 30 days along with isometric hand exercise, whereas those in the test arm received FIR therapy twice weekly, 40 min session each, for 4 weeks. A biopsy from venous end was taken during fistula surgery. Doppler study of AVF was done at the end of the 4^th and 12^th week to assess AVF. Vascular access guidelines proposed by National Kidney Foundation –Kidney Disease Outcomes Quality Initiative (NKF- KDOQI) in 2006 were adapted to define the maturation of AVF.

Results:

Out of 107 patients, 51 were randomized to the test arm and 56 to the control arm. During follow-up, the blood flow rate through AVF (Qa) and the diameter of the cephalic vein draining (CVd) the AVF were measured. At the end of 3 months, Qa in Radio-Cephalic Fistula (RCF) was high in the test arm (p–0.003). The AVF failures were 5 (10.2%) and 14 (28%) in the test and control arms, respectively (p: 0.025). However, when adjusted for AVF failure within 6 h of surgery (may be related to surgical technique) this difference in AVF patency was statistically insignificant (p: 0.121). The mean Qa was high in patients with an arterial intimal medial thickness (AIMT) <0.5 mm. The IMT of the anastomosed artery had statistically significant correlation with the primary failure rate of AVF (P < 0.001).

Conclusion:

In patients with CKD, FIR therapy was effective in increasing the AVF blood flow rate at the end of 3 months, though the difference in primary failure rate was statistically insignificant.

Vascular access as a survival factor for the hemodialysis population: a retrospective study

BACKGROUND

The creation of vascular access is an essential condition for providing hemodialysis, which remains the only option for most patients suffering from end-stage renal disease. Selection of the type of vascular access affects patients' clinical outcomes, access maintenance frequency, risk of infection and major adverse cardiac events during dialysis. To improve the decision-making process, we performed a retrospective clinical data analysis of dialyzed patients and critically compared the survival rates between two types of vascular access applied during dialysis therapy during a 5 years follow-up period.

METHODS

Using nationally representative data from 18 dialysis centers across Slovakia, we explore and compare survival rates of 960 adult patients undergoing hemodialysis using either a central venous catheter (CVC) or an arteriovenous fistula (AVF). Length of dialysis, protein malnutrition and comorbidities were examined as possible covariates that might influence survival rates.

RESULTS

Chances of surviving for a one-year period were higher by 52% in AVF patients compared to CVC patients (HR 1.52; 95% CI 1.27-1.83; P<0.001) regardless of age, sex, nutritional status, time spent on dialysis and comorbidities. The presence of cardiac congestion (HR 1.26 [95% CI 1.06-1.50], P<0.01) and malnutrition (protein malnutrition: HR 0.98 [95% CI 0.96-1.00], P<0.05; lean tissue index: HR 0.79 [95% CI 0.67-0.93], P<0.01) decreases chances for survival.

CONCLUSIONS

A functional arteriovenous fistula is a significant predictor of survival in the population dependent on hemodialysis, independently of sociodemographic parameters and serious comorbidities. Therefore, if various types of vascular accesses are applicable for the patient, AVF should be prioritized over CVC.

Vascular Access Failure - Cause or Complication of Central Venous Catheterization: Case Report

The quality of life and patient survival rate in terminal chronic renal insufficiency depends on the duration of vascular approaches. Dialysis catheters are used to establish an adequate vascular approach when emergency hemodialysis is indicated and when all approaches are exhausted. Complications of CVC can be classified into three categories: mechanical (hematoma, arterial puncture, pneumothorax, hemothorax, catheter misplacement, and stenosis), infectious (insertion site infection, CVC colonization, and bloodstream infection) and thrombotic (deep vein thrombosis). Despite the increasing prevalence of haemodialysis patients with complex access issues, there remains no consensus on the definition of vascular access failure or end-stage vascular access. The dilema in these cases remains whether the generalized vascular insufficiency is the cause or a complication of exhausted vascular accesses. This case report is one of the examples of combined complications with generalized vascular access insufficiency. During the year and a half of the chronic dialysis program, the patient had several changes of vascular approaches, and each approach became dysfunctional in certain time due to various causes. After six months of successful hemodialysis, the patient was admitted with signs of infection and during hospitalization was again subjected to multiple changes of the vascular approach due to infection, thrombosis, and vascular access failure.

A double-blind, randomized, placebo-controlled pilot trial to evaluate safety and efficacy of vorapaxar on arteriovenous fistula maturation

BACKGROUND

Protease-activated receptor-1 antagonism by vorapaxar could facilitate arteriovenous fistula maturation but may increase bleeding risk.

OBJECTIVE

The primary objective of the Vorapaxar Study for Maturation of arteriovenous fistula for Hemodialysis Access (VorapAccess) was to determine if vorapaxar improves arteriovenous fistula functional maturation in patients with end-stage renal disease.

METHODS

VorapAccess was a randomized, placebo-controlled, double-blind pilot trial comparing 2.5 mg vorapaxar per day with placebo for twelve weeks starting on day two after arteriovenous fistula creation. The primary outcome was time to functional maturation defined as successful cannulation for six hemodialysis sessions within three weeks. The planned sample size was 50 participants. The study was terminated early after withdrawal of planned financial support. Given the small number of randomized patients, we performed descriptive analyses without inference testing.

RESULTS

A total of 13 participants were randomly allocated study drug (six vorapaxar and seven placebo). The median age was 56 years and seven participants (54%) were female. The median (minimum-maximum) days to functional maturation were 169 (77-287) days in the vorapaxar group and 145 (48-198) days in the placebo group. Six of the 13 (46%) participants had arteriovenous fistula functional maturation within 180 days; two of six (33%) in the vorapaxar group and four of seven (57%) in the placebo group. There was one bleeding event in the placebo group.

CONCLUSION

Fewer than half of participants had functional maturation within 180 days after surgery, suggesting a major need for agents or strategies that enhance arteriovenous fistula maturation.

Outcomes of vascular access in hemodialysis patients: Analysis based on the Korean National Health Insurance Database from 2008 to 2016

Background

Controversies exist whether arteriovenous fistula (AVF) placement is preferred over arteriovenous graft (AVG) for elderly patients. Current guidelines did not offer specific recommendations. Thus, this study was conducted to analyze the all-cause mortality and primary patency associated with various vascular access (VA) types according to age group.

Methods

This retrospective observational study investigated the Korean insurance claims data of chronic kidney disease patients who began hemodialysis between January 2008 and December 2016. We investigated all-cause mortality associated with initial VA in incident hemodialysis patients and primary patency between AVF and AVG according to age group.

Results

The proportion of patients with a tunneled dialysis catheter (TDC) that was first placed for VA increased from 18.4% in 2008 to 52.3% in 2016. Incident hemodialysis patients with a TDC or AVG for the initial VA had significantly higher mortality risk than patients with an AVF, except for patients over 85 years, who showed no significant difference in all-cause mortality regardless of VA type. In the patency analysis on initial AV access, AVG had significantly poorer primary patency than AVF in all age groups.

Conclusion

AVF had better patency than AVG in all age groups; however, the benefit of AVF attenuated in the older age groups. The mortality rate between AVF and AVG was not significantly different in patients over 85 years. Therefore, a “patient-first” approach should be emphasized over a “fistula-first” approach in AV access creation for incident hemodialysis patients older than 85 years.

Hemodialysis vascular access in the elderly-getting it right

Choosing the optimal hemodialysis vascular access for the elderly patient is best achieved by a patient-centered coordinated multidisciplinary team approach that aligns the patient's end-stage kidney disease Life-Plan, i.e., the individual treatment approach (supportive care, time-limited or long-term kidney replacement therapy, or combination thereof) and selection of dialysis modality (peritoneal dialysis versus hemodialysis) with the most suitable dialysis access. Finding the right balance between the patient's preferences, the likelihood of access function and survival, and potential complications in the context of available resources and limited patient survival can be extremely challenging. The framework for choosing the most appropriate vascular access for the elderly presented in this review considers the individual end-stage kidney disease Life-Plan, the patient life expectancy, the likelihood of access function and survival, the timing of dialysis relative to access placement, prior access history, and patient preference. This complex decision-making process should be dynamic in order to accommodate patients' changing needs and life and health circumstances. Effective and timely communication between the patient, their caregivers, and treating team is key to delivering truly patient-centered care. Delivering this care also requires overcoming the limitations of the currently available evidence that is predominantly based on observational data with its inherent risks of bias. While challenging, future randomized controlled studies exploring the risks, benefits, costs, and timing of placement of available access types in the elderly are required to help us "get it right" for our patients.

Beyond the Technical: Determining Real Indications for Vascular Access and Hemodialysis Initiation in End-Stage Renal Disease

Determining valid indications for vascular access creation and hemodialysis initiation in end-stage renal disease requires utilization of verified prognostication tools and recognition of triggers to initiate serious conversations, and implementation of concurrent palliative care and/or hospice care is recommended. Establishment of a multi-disciplinary team that includes consideration of interventionalists in the pre-dialysis medical situation is important. A "catheter best" approach may be the most appropriate for some patients to meet goals of care.

Vascular Access for Hemodialysis Patients: New Data Should Guide Decision Making

This commentary critically examines key assumptions and recommendations in the 2006 Kidney Disease Outcomes Quality Initiative vascular access guidelines, and argues that several are not relevant to the contemporary United States hemodialysis population. First, the guidelines prefer arteriovenous fistulas (AVFs) over arteriovenous grafts (AVGs), on the basis of their superior secondary survival and lower frequency of interventions and infections. However, intent-to-treat analyses that incorporate the higher primary failure of AVFs, demonstrate equivalent secondary survival of both access types. Moreover, the lower rate of AVF versus AVG infections is counterbalanced by the higher rate of catheter-related bloodstream infections before AVF maturation. In addition, AVFs with assisted maturation (interventions before successful AVF use), which account for about 50% of new AVFs, are associated with inferior secondary patency compared with AVGs without intervention before successful use. Second, the guidelines posit lower access management costs for AVFs than AVGs. However, in patients who undergo AVF or AVG placement after starting dialysis with a central venous catheter (CVC), the overall cost of access management is actually higher in patients receiving an AVF. Third, the guidelines prefer forearm over upper arm AVFs. However, published data demonstrate superior maturation of upper arm versus forearm AVFs, likely explaining the progressive increase in upper arm AVFs in the United States. Fourth, AVFs are thought to fail primarily because of aggressive juxta-anastomotic stenosis. However, recent evidence suggests that many AVFs mature despite neointimal hyperplasia, and that suboptimal arterial vasodilation may be an equally important contributor to AVF nonmaturation. Finally, CVC use is believed to result in excess mortality in patients on hemodialysis. However, recent data suggest that CVC use is simply a surrogate marker of sicker patients who are more likely to die, rather than being a mediator of mortality.

Reporting quality of pilot clinical trials in chronic kidney disease patients on hemodialysis: a methodological survey

BACKGROUND

The conduct of high-quality pilot studies can help inform the success of larger clinical trials. Guidelines have been recently developed for the reporting of pilot trials.

OBJECTIVE

This methodological survey evaluates the completeness of reporting in pilot randomized controlled trials in chronic kidney disease patients on hemodialysis (HD patients) and explores factors associated with better completion of reporting.

METHODS

The authors searched Pubmed on July 1, 2018, for all pilot trials conducted in HD patients. Reporting quality was assessed against the 40-item Consolidated Standards of Reporting Trials (CONSORT) Extension for Pilot Trials. Study factors including year and country of publication, intervention, number of centers, type of funding, and journal endorsement of CONSORT were also examined.

RESULTS

The mean number of items reported from the CONSORT extension for pilot trials across all included articles was 18.4 (standard deviation [SD] = 4.4). In the adjusted analysis, studies reported in later years (IRR = 1.026, 95% CI [1.018, 1.034], p < 0.001) and an increase of 20 persons in sample size (adjusted IRR = 1.021, 95% CI [1.010, 1.031], p < 0.001) were associated with a significantly higher number of CONSORT pilot items reported.

CONCLUSIONS

Current reporting completeness of pilot trials in HD patients is suboptimal. Endorsing the CONSORT extension specific to pilot and feasibility studies and ensuring that pilot trials focus on the feasibility objectives may improve reporting completeness of these trials.

Patency rates of arteriovenous fistulas created before versus after hemodialysis initiation

In an incident hemodialysis (HD) population, we aimed to investigate whether arteriovenous fistula (AVF) creation before HD initiation was associated with improved AVF patency compared with AVF creation from a central venous catheter (CVC), and also to compare patient survival between these patients. Between January 2011 and December 2013, 524 incident HD patients with identified first predialysis vascular access with an AVF (pre-HD group, n = 191) or an AVF from a CVC (on-HD group, n = 333) were included and analyzed retrospectively. The study outcome was defined as AVF patency and all-cause mortality (time to death). On Kaplan-Meier survival analysis, primary and secondary AVF patency rates did not differ significantly between the two groups (P = 0.812 and P = 0.586, respectively), although the overall survival rate was significantly higher in the pre-HD group compared with the on-HD group (P = 0.013). On multivariate analysis, well-known patient factors were associated with decreased primary (older age and diabetes mellitus [DM]) and secondary (DM and peripheral arterial occlusive disease) AVF patency, whereas use of a CVC as the initial predialysis access (hazard ratios, 1.84; 95% confidence intervals, 1.20-2.75; P = 0.005) was significantly associated with worse survival in addition to well-known patient factors (older age, diabetes mellitus, and peripheral arterial occlusive disease). Worse survival in the on-HD group was likely confounded by selection bias because of the retrospective nature of our study. Therefore, the observed lower mortality associated with AVF creation before HD initiation is not fully attributable to CVC use, but rather, affected by other patient-level prognostic factors. There were no CVC-related complications in the pre-HD group, whereas 10.2% of CVC-related complications were noted in the on-HD group. In conclusion, among incident HD patients, compared with patients who underwent creation of an AVF from a CVC, initial AVF creation showed similar primary and secondary AVF patency rates, but lower mortality risk. We also observed that an initial CVC use was an independent risk factor associated with worse survival. A fistula-first strategy might be the best option for incident HD patients who are good candidates for AVF creation.

Comparison of Outcomes of Hybrid and Surgical Correction for De Novo Arteriovenous Graft Occlusion

Purpose

This study aimed to compare surgical revisions and balloon angioplasty after surgical thrombectomy on thrombosed dialysis access as a first event.

Materials and Methods

Records of patients undergoing creation of arteriovenous grafts (AVGs) at the Gachon University Gil Medical Center between March 2008 and February 2016 were reviewed. Among them, patients who underwent treatment on first-time thrombotic occlusion after AVG creation were identified. Outcomes were primary, primary-assisted, and secondary patency. The patency was generated using the Kaplan-Meier method, and patency rates were compared by log-rank test.

Results

A total of 59 de novo interventions (n=26, hybrid interventions; n=33, surgical revisions) for occlusive AVGs were identified. The estimated 1-year primary patency rates were 47% and 30% in the surgery and hybrid groups, respectively. The estimated primary patency rates were not different between the two groups (log-rank test, P=0.73). The Kaplan-Meier estimates of 6 and 12 months for primary-assisted patency rates were 68% and 57% in the surgery group and 56% and 56% in the hybrid group. The Kaplan-Meier estimates of 12 and 24 months secondary patency rates were 90% and 71% in the surgery group and 79% and 62% in the hybrid group. There were no differences in the estimated primary-assisted and secondary patency rates between the two groups.

Conclusion

Our results showed no significant difference between the two groups in terms of primary patency (P=0.73), primary-assisted patency (P=0.85), and secondary patency (P=0.78). However, percutaneous transluminal angioplasty can give more therapeutic options for both surgeons and patients.

Prediction of Arteriovenous Fistula Clinical Maturation from Postoperative Ultrasound Measurements: Findings from the Hemodialysis Fistula Maturation Study

BACKGROUND

The utility of early postoperative ultrasound measurements in predicting arteriovenous fistula (AVF) clinical maturation is uncertain.

METHODS

We investigated the relationships of ultrasound parameters with AVF clinical maturation in newly created AVF, measured at 1 day and 2 and 6 weeks, in 602 participants of a multicenter, observational cohort study. A backward elimination algorithm identified ultrasound measurements that independently predicted unassisted and overall AVF maturation. Candidate variables included AVF blood flow, diameter, and depth, upper arm arterial diameter, presence of stenosis, presence of accessory veins, seven case-mix factors (age, sex, black race, AVF location, diabetes, dialysis status, and body mass index), and clinical center. We evaluated the accuracy of the resulting models for clinical prediction.

RESULTS

At each ultrasound measurement time, AVF blood flow, diameter, and depth each predicted in a statistically significant manner both unassisted and overall clinical maturation. Moreover, neither the remaining ultrasound parameters nor case-mix factors were associated with clinical AVF maturation after accounting for blood flow, diameter, and depth, although maturation probabilities differed among clinical centers before and after accounting for these parameters. The crossvalidated area under the receiver operating characteristic curve for models constructed using these three ultrasound parameters was 0.69, 0.74, and 0.79 at 1 day and 2 and 6 weeks, respectively, for unassisted AVF clinical maturation and 0.69, 0.71, and 0.76, respectively, for overall AVF maturation.

CONCLUSIONS

AVF blood flow, diameter, and depth moderately predicted unassisted and overall AVF clinical maturation. The other factors considered did not further improve AVF maturation prediction.

Vascular Surgery and Geriatric Patients

As the population ages, surgical decision-making in vascular surgery has become more complex. Older patients may not have been offered vascular surgical intervention in the past because of prohibitive physiologic demands and poor health. Patients now have more aggressive management of vascular risk factors with medications, such as statin therapy, and less invasive endovascular or hybrid treatment options. Outcomes in elderly patients may not be comparable with younger patients for entities such as aortic aneurysm repair, carotid endarterectomy, or lower extremity revascularization. Despite this, desirable outcomes can be successfully achieved and should be offered to carefully selected elderly individuals.

Spanish Clinical Guidelines on Vascular Access for Haemodialysis

Vascular access for haemodialysis is key in renal patients both due to its associated morbidity and mortality and due to its impact on quality of life. The process, from the creation and maintenance of vascular access to the treatment of its complications, represents a challenge when it comes to decision-making, due to the complexity of the existing disease and the diversity of the specialities involved. With a view to finding a common approach, the Spanish Multidisciplinary Group on Vascular Access (GEMAV), which includes experts from the five scientific societies involved (nephrology [S.E.N.], vascular surgery [SEACV], vascular and interventional radiology [SERAM-SERVEI], infectious diseases [SEIMC] and nephrology nursing [SEDEN]), along with the methodological support of the Cochrane Center, has updated the Guidelines on Vascular Access for Haemodialysis, published in 2005. These guidelines maintain a similar structure, in that they review the evidence without compromising the educational aspects. However, on one hand, they provide an update to methodology development following the guidelines of the GRADE system in order to translate this systematic review of evidence into recommendations that facilitate decision-making in routine clinical practice, and, on the other hand, the guidelines establish quality indicators which make it possible to monitor the quality of healthcare.

A completely biological "off-the-shelf" arteriovenous graft that recellularizes in baboons

Prosthetic arteriovenous grafts (AVGs) conventionally used for hemodialysis are associated with inferior primary patency rates and increased risk of infection compared with autogenous vein grafts. We tissue-engineered an AVG grown from neonatal human dermal fibroblasts entrapped in bovine fibrin gel that is then decellularized. This graft is both "off-the-shelf" (nonliving) and completely biological. Grafts that are 6 mm in diameter and about 15 cm in length were evaluated in a baboon model of hemodialysis access in an axillary-cephalic or axillary-brachial upper arm AVG construction procedure. Daily antiplatelet therapy was given. Grafts underwent both ultrasound assessment and cannulation at 1, 2, 3, and 6 months and were then explanted for analysis. Excluding grafts with cephalic vein outflow that rapidly clotted during development of the model, 3- and 6-month primary patency rates were 83% (5 of 6) and 60% (3 of 5), respectively. At explant, patent grafts were found to be extensively recellularized (including smoothelin-positive smooth muscle cells with a developing endothelium on the luminal surface). We observed no calcifications, loss of burst strength, or outflow stenosis, which are common failure modes of other graft materials. There was no overt immune response. We thus demonstrate the efficacy of an off-the-shelf AVG that is both acellular and completely biological.

Early cannulation grafts for haemodialysis: An updated systematic review

Purpose:

Early cannulation grafts are specifically designed for dialysis, whereas standard expanded polytetrafluoroethylene grafts were not. There is developing collective experience and literature available to allow the assessment of outcomes of these early cannulation grafts. The aim of this review was to review the evidence for both short- and long-term outcomes of early cannulation grafts.

Methods:

Using standardized searches of electronic databases in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses, the primary outcomes for this study were primary and secondary patency rates for early cannulation grafts for dialysis at 12 months and beyond. Secondary outcomes were timing of first cannulation, rates of access thrombosis, steal syndrome, pseudo-aneurysm and infection.

Results:

A total of 19 studies were identified and included. These were divided into different graft types. Flixene™, Avflo™, Acuseal™ and Vectra™ grafts all showed that early cannulation within 72 h is possible. Twelve-month pooled primary and secondary patency rates were 43.3% (95% confidence interval: 31.6–55.4) and 73.4% (95% confidence interval: 63–82.7) for the Flixene graft, 58.2% (95% confidence interval: 48–68.1) and 79.2% (95% confidence interval: 68–88.7) for the Avflo graft, 43.6% (95% confidence interval: 30.7–56.9) and 70.5% (95% confidence interval: 49.7–87.8) for the Acuseal graft and 63.7% (95% confidence interval: 53.4–73.4) and 85.8% (95% confidence interval: 82.9–88.4) for the Vectra graft. Data for outcome beyond 12 months were limited to the more recent studies.

Conclusion:

This review confirms that early cannulation is not detrimental on the early outcome of early cannulation graft patencies. It has also shown that both Vectra and Avflo grafts have adequate long-term patencies. The data do not allow specific graft recommendations, as comparative trials would be required.

Tradeoffs in Vascular Access Selection in Elderly Patients Initiating Hemodialysis With a Catheter

RATIONALE & OBJECTIVE

National vascular access guidelines recommend placement of arteriovenous fistulas (AVFs) over grafts (AVGs) in hemodialysis patients, but have not been comprehensively assessed in the elderly. We evaluated clinically relevant vascular access outcomes in elderly patients receiving an AVF or AVG after hemodialysis therapy initiation.

STUDY DESIGN

Retrospective cohort study using national administrative data.

SETTINGS & PARTCIPANTS

Claims data from the US Renal Data System of 9,458 US patients 67 years and older who initiated hemodialysis therapy from July 1, 2010, to June 30, 2011, with a catheter and received an AVF (n=7,433) or AVG (n=2,025) within the ensuing 6 months.

PREDICTOR

Arteriovenous access subtype, AVF or AVG.

OUTCOMES

Successful use of vascular access, interventions to make vascular access functional, duration of catheter dependence before successful use of vascular access, frequency of interventions, and abandonment after successful use of vascular access.

ANALYTICAL APPROACH

Multivariable logistic regression analysis was used to compare the need for intervention before successful use of AVFs and AVGs, and negative bionomial regression was used to calculate the frequency of intervention after successful use of vascular access.

RESULTS

Unsuccessful use of vascular access within 6 months of creation was higher for AVFs versus AVGs (51% vs 45%; adjusted HR, 1.86; 95% CI, 1.73-1.99). Interventions to make vascular access functional were greater in AVFs versus AVGs (42% vs 23%; OR, 2.66; 95% CI, 2.26-3.12). AVFs had a lower 1-year abandonment rate after successful use compared with AVGs (OR, 0.71; 95% CI, 0.62-0.83) and required one-fourth fewer interventions after successful use (relative risk, 0.75; 95% CI, 0.69-0.81). Patients receiving an AVF had substantially longer catheter dependence before successful use than those receiving an AVG (median time, 3 vs 1 month; P<0.001).

LIMITATIONS

Residual confounding due to vascular access choice, restriction to an elderly population, and 1-year follow-up period.

CONCLUSIONS

In elderly hemodialysis patients initiating hemodialysis therapy with a catheter, the optimal vascular access selection depends on tradeoffs between shorter catheter dependence and less frequent interventions to make the vascular access (AVG) functional versus longer access patency and fewer interventions after successful use of the vascular access (AVF).

Vascular Access Type and Clinical Outcomes among Elderly Patients on Hemodialysis

BACKGROUND AND OBJECTIVES

The optimal type of initial permanent access for hemodialysis among the elderly is controversial. Duration of central venous catheter dependence, patient comorbidities, and life expectancy are important considerations in whether to place an arteriovenous fistula or graft. We used an observational study design to compare clinical outcomes in elderly patients who initiated hemodialysis with a central venous catheter and subsequently had an arteriovenous fistula or graft placed.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We identified 9458 United States patients ages ≥67 years old who initiated hemodialysis from July 1, 2010 to June 30, 2011 with a central venous catheter and no secondary vascular access and then received an arteriovenous fistula (n=7433) or graft (n=2025) within 6 months. We evaluated key clinical outcomes during the 6 months after vascular access placement coincident with high rates of catheter use and used a matched propensity score analysis to examine patient survival.

RESULTS

Central venous catheter dependence was greater in every month during the 6-month period after arteriovenous fistula versus graft placement (P<0.001). However, rates of all-cause infection-related hospitalization (adjusted relative risk, 0.93; 95% confidence interval, 0.87 to 0.99; P=0.01) and bacteremia/septicemia-related hospitalization (adjusted relative risk, 0.90; 95% confidence interval, 0.82 to 0.98; P=0.02) were lower in the arteriovenous fistula versus graft group as was the adjusted risk of death (hazard ratio, 0.76; 95% confidence interval, 0.73 to 0.80; P<0.001).

CONCLUSIONS

Despite extended central venous catheter dependence, elderly patients initiating hemodialysis with a central venous catheter who underwent arteriovenous fistula placement within 6 months had fewer hospitalizations due to infections and a lower likelihood of death than those receiving an arteriovenous graft.

Autologous fat transplants to deliver glitazone and adiponectin for vasculoprotection

The insulin sensitizing glitazone drugs, rosiglitazone (ROS) and pioglitazone (PGZ) both have anti-proliferative and anti-inflammatory effects and induce adipose tissue (fat) to produce the vaso-protective protein adiponectin. Stenosis due to intimal hyperplasia development often occurs after placement of arteriovenous synthetic grafts used for hemodialysis. This work was performed to characterize the in vitro and in vivo effects of ROS or PGZ incorporation in fat and to determine if fat/PGZ depots could decrease vascular hyperplasia development in a porcine model of hemodialysis arteriovenous graft stenosis. Powdered ROS or PGZ (6-6000μM) was mixed with fat explants and cultured. Drug release from fat was quantified by HPLC/MS/MS, and adiponectin and monocyte chemotactic protein-1 (MCP-1) levels in culture media were measured by ELISA. The effect of conditioned media from the culture of fat with ROS or PGZ on i) platelet-derived growth factor-BB (PDGF-BB)-stimulated proliferation of human venous smooth muscle cells (SMC) was measured by a DNA-binding assay, and ii) lipopolysaccharide (LPS)-induced human monocyte release of tumor necrosis factor-alpha (TNFα) was assessed by ELISA. In a porcine model, pharmacokinetics of PGZ from fat depots transplanted perivascular to jugular vein were assessed by HPLC/MS/MS, and retention of the fat depot was monitored by MRI. A porcine model of synthetic graft placed between carotid artery and ipsilateral jugular vein was used to assess effects of PGZ/fat depots on vascular hyperplasia development. Both ROS and PGZ significantly induced the release of adiponectin and inhibited release of MCP-1 from the fat. TNF production from monocytes stimulated with LPS was inhibited 50-70% in the presence of media conditioned by fat alone or fat and either drug. The proliferation of SMC was inhibited in the presence of media conditioned by fat/ROS cultures. Fat explants placed perivascular to the external jugular vein were retained, as confirmed by MRI at one week after placement. PGZ was detected in the fat depot, in the external jugular vein wall and in adjacent tissue at clinically relevant levels, whereas levels in plasma were below detection. External jugular vein exposed to fat incorporated with PGZ had increased adiponectin expression compared to vein exposed to fat alone. However, the development of hyperplasia within the arteriovenous synthetic grafts was unchanged by treatment with fat/PGZ depots compared to no treatment.

Choice of Hemodialysis Access in Older Adults: A Cost-Effectiveness Analysis

BACKGROUND AND OBJECTIVES

Although arteriovenous fistulas have been found to be the most cost-effective form of hemodialysis access, the relative benefits of placing an arteriovenous fistula versus an arteriovenous graft seem to be least certain for older adults and when placed preemptively. However, older adults' life expectancy is heterogeneous, and most patients do not undergo permanent access creation until after dialysis initiation. We evaluated cost-effectiveness of arteriovenous fistula placement after dialysis initiation in older adults as a function of age and life expectancy.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Using a hypothetical cohort of patients on incident hemodialysis with central venous catheters, we constructed Markov models of three treatment options: (1) arteriovenous fistula placement, (2) arteriovenous graft placement, or (3) continued catheter use. Costs, utilities, and transitional probabilities were derived from existing literature. Probabilistic sensitivity analyses were performed by age group (65-69, 70-74, 75-79, 80-84, and 85-89 years old) and quartile of life expectancy. Costs, quality-adjusted life-months, and incremental cost-effectiveness ratios were evaluated for up to 5 years.

RESULTS

The arteriovenous fistula option was cost effective compared with continued catheter use for all age and life expectancy groups, except for 85-89 year olds in the lowest life expectancy quartile. The arteriovenous fistula option was more cost effective than the arteriovenous graft option for all quartiles of life expectancy among the 65- to 69-year-old age group. For older age groups, differences in cost-effectiveness between the strategies were attenuated, and the arteriovenous fistula option tended to only be cost effective in patients with life expectancy >2 years. For groups for which the arteriovenous fistula option was not cost saving, the cost to gain one quality-adjusted life-month ranged from $2294 to $14,042.

CONCLUSIONS

Among older adults, the cost-effectiveness of an arteriovenous fistula placed within the first month of dialysis diminishes with increasing age and lower life expectancy and is not the most cost-effective option for those with the most limited life expectancy.

Effect of Age on the Association of Vascular Access Type with Mortality in a Cohort of Incident End-Stage Renal Disease Patients

BACKGROUND/AIMS

All hemodialysis (HD) patients are generally recommended to create a fistula first; but to create a mature arteriovenous fistula (AVF) can be challenging in elderly individuals. It is unclear if elderly incident HD patients derive a survival benefit from an AVF over an arteriovenous graft (AVG) or a tunneled central venous catheter (TDC).

METHODS

We examined the association of vascular access type (AVF, AVG, and TDC with and without a maturing AVF/AVG at dialysis transition) at HD initiation with all-cause, cardiovascular (CV), and infection-related mortality in 46,786 US veterans using Cox models with adjustment for confounders. Effect modification by age was examined by examining associations in pre-specified age subgroups (<60, 60-<70, 70-<80, and ≥80 years old), and by including interaction terms.

RESULTS

Patients numbering 8,940 (19%) started HD with an AVF, 1,090 (3%) with an AVG, 8,262 (18%) with a TDC and a maturing AVF/AVG and 28,494 (61%) with a TDC without a maturing AVF/AVG. A total of 13,303 all-cause, 4,392 CV, and 1,058 infection-related deaths were observed in the first year after HD transition. Compared to patients with AVF, those with AVG and TDC with and without maturing AVF/AVG had incrementally higher overall risk of all-cause mortality and CV mortality. Only TDC use was associated with higher infection-associated mortality. These associations were not modified by age.

CONCLUSION

Although most of our patients consisted of male veterans and the results may not be generalized to the general population, the use of TDCs is associated with poor outcomes even in the most elderly incident HD patients.

A comparison of efficacy of endovascular versus surgical repair for the treatment of arteriovenous fistula stenosis in Taiwan

BACKGROUND

Percutaneous transluminal angioplasty (PTA) and fistula reconstruction surgery are therapeutic options for vascular access occlusion in hemodialysis patients. However, owing to its convenience, PTA has gradually become the preferred therapeutic option for fistula stenosis or occlusion. This study investigated the effects of the two therapeutic methods on the vascular access maintenance duration (number of days) and maintenance costs of fistula in dialysis patients from different dialysis units.

METHODOLOGY

In this study, 544 hemodialysis patients from 2 dialysis units in a teaching hospital in the southern area of Taiwan were included in the analysis of the frequency of PTA or revascularization surgery and the use of related medical resources by conducting a retrospective chart review.

RESULTS

The frequency of PTA in the patients undergoing long-term hemodialysis was not significantly associated with their demographic characteristics. The efficacy of PTA has declined with shorter maintenance duration with increasing PTA frequency. The cost profile of PTA was more expensive than that of fistula revascularization surgery.

CONCLUSIONS

In this study, PTA was found to be just a temporary solution for fistula thrombosis, whereas fistula reconstruction surgery is inexpensive and improves survival time. Therefore, dialysis units should establish an appropriate standard of care to avoid over-reliance on PTA in order to reduce the fistula failure rate, improve the dialysis efficacy, and reduce the psychological stress in patients, as well as to reduce the maintenance costs and rationalize the medical expenses.

Preoperative computer simulation for planning of vascular access surgery in hemodialysis patients

Introduction

The arteriovenous fistula (AVF) is the preferred vascular access for hemodialysis patients. Unfortunately, 20-40% of all constructed AVFs fail to mature (FTM), and are therefore not usable for hemodialysis. AVF maturation importantly depends on postoperative blood volume flow. Predicting patient-specific immediate postoperative flow could therefore support surgical planning. A computational model predicting blood volume flow is available, but the effect of blood flow predictions on the clinical endpoint of maturation (at least 500 mL/min blood volume flow, diameter of the venous cannulation segment ≥4 mm) remains undetermined.

Methods

A multicenter randomized clinical trial will be conducted in which 372 patients will be randomized (1:1 allocation ratio) between conventional healthcare and computational model-aided decision making. All patients are extensively examined using duplex ultrasonography (DUS) during preoperative assessment (12 venous and 11 arterial diameter measurements; 3 arterial volume flow measurements). The computational model will predict patient-specific immediate postoperative blood volume flows based on this DUS examination. Using these predictions, the preferred AVF configuration is recommended for the individual patient (radiocephalic, brachiocephalic, or brachiobasilic). The primary endpoint is FTM rate at six weeks in both groups, secondary endpoints include AVF functionality and patency rates at 6 and 12 months postoperatively.

Trial registration

ClinicalTrials.gov (NCT02453412), and ToetsingOnline.nl (NL51610.068.14).

The Usefulness of Duplex Ultrasound for Hemodialysis Access Selection

Purpose

A native vessel is preferable to an artificial graft for dialysis access. Duplex ultrasound (DUS) is noninvasive, cost-effective modality to evaluate the vessels for dialysis. The purpose of this study was to compare the rates of utilization of native vessels after preoperative imaging with DUS and contrast venography (CV).

Materials and Methods

A retrospective review was performed on patients who received an arteriovenous fistula (AVF) or arteriovenous graft (AVG) between June 2006 and July 2010. Patients were classified into 3 groups. In group 1, CV was used to evaluate the vessel. Both DUS and CV were used in group 2. In group 3, only DUS was used. The frequency of utilization of a native vessel was analyzed in each group. The chi-square test was used for statistical analysis.

Results

During the study period, 173 patients received an AVF or AVG. Eighty-nine patients were male. The mean age was 60.6±14.6 years. A native vessel was used in 56/81 patients (69.1%) and 74/81 patients (91.4%) in groups 1 and 3, respectively (P<0.001). In group 2, all patients underwent access procedures using native vessels. AVG was initially planned for 2 patients in group 2 after vessel evaluation using CV, but a native vessel was successfully used because DUS identified optimal vessels for AVF. The 1-year primary patency rate was similar in 3 groups.

Conclusion

Preoperative DUS is safe and easy to use for vessel evaluation, and can be used as a primary imaging modality for creation of access.

The Significance of Inflow Artery and Tourniquet Derived Cephalic Vein Diameters on Predicting Successful Use and Patency of Arteriovenous Fistulas for Haemodialysis

OBJECTIVE

To investigate the significance of inflow artery and cephalic vein diameters on predicting patency of radiocephalic and brachiocephalic arteriovenous fistulas (AVFs).

DESIGN

Single centre study with retrospective analysis of prospectively collected data between November 2010 and July 2015.

METHODS

A detailed history and physical examination was undertaken, including age, gender, history and duration of haemodialysis, cause of chronic kidney disease, and the presence of comorbidities/risk factors. Pre-operative arterial and venous upper extremity mapping was performed and inner vessel diameter was recorded, using a tourniquet for the veins. Outcome measures included AVF use (functionality), primary, primary assisted, secondary, and functional secondary patency.

RESULTS

One hundred and thirty five AVFs (57 and 78 radiocephalic and brachiocephalic AVFs, respectively) were constructed and followed up for 5 years. A cephalic vein diameter <4.3 mm (lower three quartiles) was the single independent predictor of inferior secondary and also functional secondary patency of radiocephalic AVFs (p = .02, HR 11.2, 95% CI 1.44-90.9). A brachial artery diameter ≤4.1 mm (lowest quartile) was an independent predictor of AVF functionality (57% vs. 83% for larger arteries, p = .017), and inferior primary, primary assisted, secondary, and functional secondary patency of brachiocephalic AVFs (primary assisted patency 21.9% vs. 55.9% at 3 years, p = .001/log-rank test, HR 3.1, p = .002/Cox regression). The presence of lower extremity PAD or use of dual antithrombotics was also independently associated with an inferior secondary patency. The number of risk factors (brachial artery diameter ≤4.1 mm, PAD, and use of dual antithrombotics) demonstrated risk stratification capabilities for functional secondary patency.

CONCLUSIONS

Among patients undergoing radiocephalic AVFs, a tourniquet derived cephalic vein diameter <4.3 mm was the single independent predictor of inferior secondary and functional secondary patency. Among patients undergoing brachiocephalic AVFs, all patency rates were inferior in the presence of a brachial artery diameter ≤4.1 mm and secondary patency was inferior in the presence of multiple risk factors.

Placement of Upper Extremity Arteriovenous Access in Patients with Central Venous Occlusions: A Novel Technique

BACKGROUND

Central venous occlusion is a common occurrence in patients with end-stage renal disease. Placement of upper extremity arteriovenous access in patients with occlusion of the brachiocephalic veins is often not an option. Avoidance of lower extremity vascular access can decrease morbidity and infection.

METHODS

The central venous lesions were crossed centrally via femoral access. The wire was retrieved in the neck extravascularly. A Hemodialysis Reliable Outflow catheter was then placed in the right atrium and completed with an arterial anastomosis.

RESULTS

We describe a novel technique for placing upper extremity arteriovenous access in patients with occlusion of the brachiocephalic veins. This technique was utilized in 3 patients. The technical success was 100%.

CONCLUSIONS

The placement of upper extremity arteriovenous access in patients with central venous occlusions is technically feasible.

Upper-arm hemodialysis access in Sweden

AIM

To provide the contemporary use of upper-arm access for hemodialysis in Sweden using data from a unique national registry for hemodialysis access.

METHODS

Data were retrieved from a nation-wide registry for dialysis access in Sweden, Dialysis Access Database (DiAD) on the use and function of specific access types with a focus on upper-arm accesses.

RESULTS

The data demonstrate an increased use of upper-arm access, likely dependent on a changing patient population, with brachiocephalic arteriovenous fistula (AVF) as the most common access type. Women received more upper-arm accesses than men. Given the recent establishment of the registry, patency and access function can at this point give preliminary data. Indications of a better function for brachiobasilic AVFs in staged procedures were observed as well as for upper-arm arteriovenous grafts (AVGs) in women.

CONCLUSIONS

Registry data support an increased use of upper-arm accesses, especially in women. The study also demonstrates the potential of a dedicated national access registry to improve access care.