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A more accurate descriptive and clinically useful diagnosis based upon pathophysiology for what is commonly referred to as venous outflow stenosis is inflow-outflow imbalance. In these cases, the total outflow capacity of the AV access is inadequate to handle the inflow volume (Qa) without an increase in pressure. The relative inadequacy of the access outflow capacity in comparison to Qa results in increased outflow resistance and a proportional increase in intraluminal pressure. The clinical indicators associated with venous stenosis are the resulting manifestations of this imbalance. The point at which this occurs is dependent upon variations in these two parameters-Qa and outflow resistance. The variations in these two parameters are considerable and reciprocal. Excessive Qa results in or can lead to an entire list of serious problems that adversely affect patient morbidity and mortality. Most studies dealing with AV access Qa reduction have been for the treatment of an existing condition rather than its prevention; however, prevention of disease rather than waiting for its development is an important tenet of medical practice. The resulting clinical picture of inflow-outflow imbalance is taken as an indication for corrective treatment. In the past, in most cases this has meant angioplasty to open the outflow if it is reduced; however, this clinical picture may be associated with an excessive Qa and angioplasty in these cases creates the risk for a further increase in Qa. It is the authors' opinion that access flow measurements should be a part of the evaluation of these cases prior to planning treatment. Using this information, a bimodal approach to primary treatment should be adopted involving either angioplasty for cases with a low or normal Qa or flow reduction in cases with an elevated Qa., Competing Interests: Declaration of conflicting interestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Introduction: The long-term survival and low complication rate of autogenous fistulas for hemodialysis access is often offset by early thrombosis and slow or failed maturation leading to the use of central venous catheters. A regenerative material may have the potential to overcome these limitations. A completely biological acellular vascular conduit was investigated in this first-in-human clinical study., Methods: With approval of the ethics board and patients' informed consent, five subjects were enrolled based on predetermined inclusion criteria. Five patients underwent implant of a novel acellular, biological tissue conduit (TRUE AVC™) in the upper arm in a curved configuration between brachial artery and axillary vein. After maturation, standard dialysis was commenced through the new access. Patients were followed up to 26 weeks with ultrasound and physical exam. Serum samples were evaluated for an immune response to the novel allogeneic human tissue implant., Results: This new tissue conduit handled well surgically, with properties similar to that of native human vein. Post procedure conduit flow was excellent in all cases, averaging 1098 ± 388 ml/min at week 4 and remaining stable through 1248 ± 355 ml/min at 26 weeks. Surgical site healing was normal with no edema or erythema by week 4. Six-month primary assisted patency was 80% and secondary patency was 100%. Prescribed dialysis was successfully delivered without infection, and there was no significant change in conduit diameter. Serum testing showed no increase in PRA or IgG specific to the TRUE AVC. One implant required intervention at 5 months with thrombectomy and covered stent procedure., Conclusion: This first-in-human 6-month study with favorable patency and low complication rate establishes the initial safety and feasibility of this novel biological tissue conduit for dialysis access in patients with end-stage kidney disease. Its mechanical durability and lack of immune response establishes TRUE AVC as a potential regenerative material for clinical use., Competing Interests: Declaration of conflicting interestsAH, CP, KG, MM, KS, RM, MS and ZS are share-holders and employee of Vascudyne. HW is paid consultant for Vascudyne.

Background: The perforator vein determines whether it is feasible to create a percutaneous (pAVF) or surgical "Gracz-type" arteriovenous fistula (sAVF). Creating a standard anatomic classification of the antecubital region is beneficial to both the selection of the appropriate device and/or procedure and technical outcomes. Accordingly, an analysis of a large cohort of patients undergoing pAVF/sAVF was performed, focusing on perforator vein anatomical suitability, and a novel anatomical classification of the antecubital region was developed and proposed., Methods: Between August 2018 and July 2022, chronic or end-stage kidney disease patients as well as patients anticipated an initiation of apheresis, who were referred for vascular access planning, underwent a standardized evaluation of upper extremities. A vessel mapping summary detailing the vasculature and the access creation plan was completed, indicating the anatomical suitability for sAVF and pAVF (Ellipsys and WavelinQ) techniques., Results: Of 524 patients, 36.5% were female (average age 65 years). 53.2% were on dialysis, 41.6% had diabetes, and 13.2% had a previously failed permanent dialysis access. The anatomy for successful pAVF creation was judged to be suitable in 54% of patients for an Ellipsys-pAVF, and 29.8% for WavelinQ-pAVF. Of the WavelinQ group, 54.4% had suitable anatomy for ulnar, 26.9% for radial, and 18.6% for both ulnar/radial anastomoses. Additionally, 60.7% had suitable anatomy for pAVF creation with at least one of the systems, while 22.5% were suited for both types of pAVF-systems. 80.3% were candidates for creation of a Gracz-AVF., Conclusion: Overall, we found that about 60% of patients are likely candidates for a pAVF, with 80% being candidates for creation of a Gracz-AVF. Male patients have significantly higher suitability for most types of AVF creation, and younger patients are more suitable for Ellipsys-pAVF and RCAVFs. Most importantly, a universal classification of perforator vein was developed, which is indispensable in modern vascular access planning., Competing Interests: Declaration of conflicting interestsThe author(s) declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article: RS: consultant for Becton Dickinson and Company, Medtronic, Laminate Medical Technologies, Bluegrass Vascular Technologies; speaker fees from W.L. GORE. KK: no competing interests. SS: no competing interests. HW: consultant for Medtronic, Vascudyne, Bluegrass Vascular Technologies.

Mechanisms underlying long COVID remain poorly understood. Patterns of immunological responses in individuals with long COVID may provide insight into clinical phenotypes. Here we aimed to identify these immunological patterns and study the inflammatory processes ongoing in individuals with long COVID. We applied an unsupervised hierarchical clustering approach to analyze plasma levels of 42 biomarkers measured in individuals with long COVID. Logistic regression models were used to explore associations between biomarker clusters, clinical variables, and symptom phenotypes. In 101 individuals, we identified three inflammatory clusters: a limited immune activation cluster, an innate immune activation cluster, and a systemic immune activation cluster. Membership in these inflammatory clusters did not correlate with individual symptoms or symptom phenotypes, but was associated with clinical variables including age, BMI, and vaccination status. Differences in serologic responses between clusters were also observed. Our results indicate that clinical variables of individuals with long COVID are associated with their inflammatory profiles and can provide insight into the ongoing immune responses., Competing Interests: GC is an Abbott Laboratories employee and shareholder. AL is a consultant with Abbott Laboratories. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be constructed as a potential conflict of interest., (Copyright © 2024 Dhingra, Fu, Cloherty, Mallon, Wasse, Moy, Landay and Kenny.)

Brachiocephalic arteriovenous fistulas (AVF) makeup approximately one third of prevalent dialysis vascular accesses. The most common cause of malfunction with this access is cephalic arch stenosis (CAS). The accepted requirement for treatment of a venous stenosis lesion is ⩾50% stenosis associated with hemodynamically abnormalities. However, the correlation between percentage stenosis and a clinically significant decrease in access blood flow (Qa) is low. The critical parameter is the absolute minimal luminal diameter (MLD) of the lesion. This is the parameter that exerts the key restrictive effect on Qa and results in hemodynamic and functional implications for the access. CAS is the result of low wall shear stress (WSS) resulting from the effects of increased blood flow and the unique anatomical configuration of the CAS. Decrease in WSS has a linear relationship to increased blood flow velocity and neointimal hyperplasia exhibits an inverse relationship with WSS. The result is a stenotic lesion. The presence of downstream venous stenosis causes an inflow-outflow mismatch resulting in increased pressure within the access. Qa in this situation may be decreased, increased, or within a normal range. Over time, the increased intraluminal pressure can result in marked aneurysmal changes within the AVF, difficulties with cannulation and the dialysis treatment, and ultimately, increasing risk of access thrombosis. Complete characterization of the lesion both hemodynamically and anatomically should be the first step in developing a strategy for management. This requires both access flow measurement and angiographic imaging. Patients with CAS present a relatively broad spectrum as relates to both of these parameters. These data should be used to determine whether primary treatment of CAS should be directed toward the anatomical lesion (small MLD and low Qa) or the pathophysiology (large MLD and high Qa).

Long COVID, a type of post-acute sequelae of SARS-CoV-2 (PASC), has been associated with sustained elevated levels of immune activation and inflammation. However, the mechanisms that drive this inflammation remain unknown. Inflammation during acute coronavirus disease 2019 could be exacerbated by microbial translocation (from the gut and/or lung) to blood. Whether microbial translocation contributes to inflammation during PASC is unknown. We did not observe a significant elevation in plasma markers of bacterial translocation during PASC. However, we observed higher levels of fungal translocation - measured as β-glucan, a fungal cell wall polysaccharide - in the plasma of individuals experiencing PASC compared with those without PASC or SARS-CoV-2-negative controls. The higher β-glucan correlated with higher inflammation and elevated levels of host metabolites involved in activating N-methyl-d-aspartate receptors (such as metabolites within the tryptophan catabolism pathway) with established neurotoxic properties. Mechanistically, β-glucan can directly induce inflammation by binding to myeloid cells (via Dectin-1) and activating Syk/NF-κB signaling. Using a Dectin-1/NF-κB reporter model, we found that plasma from individuals experiencing PASC induced higher NF-κB signaling compared with plasma from negative controls. This higher NF-κB signaling was abrogated by piceatannol (Syk inhibitor). These data suggest a potential targetable mechanism linking fungal translocation and inflammation during PASC.

As numerous complex pathologies stem from cellular energy dysfunction, we aimed to elucidate mitochondrial function and associated stress pathologies in kidney disease in a cohort of hemodialysis patients with end-stage kidney disease (ESKD). The bioenergetics study was conducted using peripheral blood mononuclear cells (PBMCs) of ESKD patients (n = 29) and healthy controls (no ESKD, n = 10). PBMCs were isolated from whole blood and seeded into assay plates to detect changes in oxidative phosphorylation and glycolysis. The bioenergetics analysis (i.e., mitochondrial stress test) was performed using Seahorse XFe24 flux analyzer. We observed significant reduction in mitochondrial respiration in patient PBMCs in terms of fundamental bioenergetics parameters such as basal respiration, ATP turnover, maximal respiration and spare respiratory capacity. These findings were correlated with the expression levels of proteins coordinating cellular energy status and regulating mitochondrial dynamics. Our data demonstrates an association between mitochondrial oxygen consumption of PBMCs and ESKD. AMPK activity, its downstream effector PGC-1α and mitochondrial fission/fusion proteins are partially responsible for the decrease in oxidative phosphorylation of PBMCs isolated from ESKD patients. We propose a link between mitochondrial dysfunction and ESKD and a role for mitochondria as a potential site for therapeutic interventions., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Altintas, DiBartolo, Tadros, Samelko and Wasse.)

Rationale & Objective: Optimizing vascular access use is crucial for long-term hemodialysis patient care. Because vascular access use varies internationally, we examined international differences in arteriovenous fistula (AVF) patency and time to becoming catheter-free for patients receiving a new AVF., Study Design: Prospective cohort study., Setting & Participants: 2,191 AVFs newly created in 2,040 hemodialysis patients in 2009 to 2015 at 466 randomly selected facilities in the Dialysis Outcomes and Practice Patterns Study (DOPPS) from the United States, Japan, and EUR/ANZ (Belgium, France, Germany, Italy, Spain, Sweden, United Kingdom, Australia, and New Zealand)., Predictors: Demographics, comorbid conditions, dialysis vintage, body mass index, AVF location, and country/region., Outcomes: Primary/cumulative AVF patency (from creation), primary/cumulative functional patency (from first use), catheter dependence duration, and mortality., Analytical Approach: Outcomes estimated using Cox regression., Results: Across regions, mean patient age ranged from 61 to 66 years, with male preponderance ranging from 55% to 66%, median dialysis vintage of 0.3 to 3.2 years, with 84%, 54%, and 32% of AVFs created in the forearm in Japan, EUR/ANZ, and United States, respectively. Japan displayed superior primary and cumulative patencies due to higher successful AVF use, whereas cumulative functional patency was similar across regions. AVF patency associations with age and other patient characteristics were weak or varied considerably between regions. Catheter-dependence following AVF creation was much longer in EUR/ANZ and US patients, with nearly 70% remaining catheter dependent 8 months after AVF creation when AVFs were not successfully used. Not using an arteriovenous access within 6 months of AVF creation was related to 53% higher mortality in the subsequent 6 months., Limitations: Residual confounding., Conclusions: Our findings highlight the need to reevaluate practices for optimizing long-term access planning and achievable AVF outcomes, especially AVF maturation. New AVFs that are not successfully used are associated with long-term catheter exposure and elevated mortality risk. These findings highlight the importance of selecting the best access type for each patient and developing effective clinical pathways for when AVFs fail to mature successfully., (Copyright © 2020 The Authors. Published by Elsevier Inc. All rights reserved.)

Background: Vasodilator nuclear stress testing is frequently ordered for risk stratification prior to kidney transplantation. Since 82 Rb-positron emission tomography-computed tomography can measure myocardial blood flow (MBF), the response to vasodilator stress can be verified rendering the results of the scan more reliable., Methods: We reviewed the MBF response to dipyridamole infusion in 328 patients with end-stage kidney disease (ESKD) prior to transplant (188 hemodialysis-HD, 120 peritoneal dialysis-PD, and 20 pre-dialysis patients-CKD5) and in 100 controls with normal kidney function. A stress/rest MBF ratio ≥ 2 was considered an adequate response to dipyridamole. Coronary artery calcium (CAC) was measured on CT., Results: Inadequate MBF response was seen in 36%-HD, 21%-PD, 45%-CKD5 vs. 23%-controls (p = 0.006). Univariable predictors of poor MBF response in ESKD patients were age, diabetes mellitus, and CAC (all p < 0.03) while serum hemoglobin was borderline significant (p = 0.052). Multivariable predictors of a poor MBF response were age (p = 0.002) and lower serum hemoglobin (p = 0.014). Ischemia was identified in 8% of ESKD patients and 24% of controls (p < 0.001)., Conclusions: ESKD patients are less likely to respond appropriately to vasodilator stress compared to patients with normal renal function and had a lower incidence of ischemia despite a high pre-test probability of disease. Physicians performing vasodilator stress without MBF measurement should be aware of the high probability of a false negative response.

Purpose: Thoracic central venous obstruction is commonly associated with the use of central venous catheters. The Surfacer System to Facilitate Access in Venous Occlusions Study was an Food and Drug Administration-approved US Investigational Device Exemption study designed to evaluate the performance and safety of the Surfacer System when used to facilitate central venous access in patients with thoracic central venous obstruction., Methods: Thirty patients were enrolled in this prospective, multicenter, single-arm study between December 2017 and May 2019. Device performance and adverse events were collected peri-procedurally and at discharge. Enrollment included 15 female and 15 male subjects with a mean age of 55.5 ± 12.9 (range: 30-79) years. Twenty-eight patients (93.3%) required central venous access for hemodialysis access. Locations of thoracic central venous obstruction were graded from 1 to 4 based on severity and extension of venous occlusions. Seven patients (23.3%) had type 1, 6 (20.0%) type 2, 16 (53.3%) type 3, and 1 (3.3%) type 4 obstruction., Results: Successful central venous catheter placement was achieved in 27 of 30 patients (90.0%). The procedure was discontinued in three (10.0%) due to tortuous anatomy discovered intraprocedurally. All 27 patients with successful CVC placement achieved adequate catheter patency and tip positioning with a mean overall procedural time and time to achieve central venous access with the Surfacer System being 44.1 ± 30.6 and 19.1 ± 25.1 min, respectively. There were no device-related adverse events or catheter malposition., Conclusion: The results of the SAVEUS Study confirm the safety and efficacy of the Surfacer System and the Inside-Out procedure when used for the placement of right-sided central venous access in patients with thoracic central venous obstruction.

End-stage kidney disease patients who are candidates for surgical arteriovenous fistula creation commonly experience obstacles to a functional surgical arteriovenous fistula, including protracted wait time for creation, poor maturation, and surgical arteriovenous fistula dysfunction that can result in significant patient morbidity. The recent approval of two endovascular devices designed to create a percutaneous arteriovenous fistula enables arteriovenous fistula creation to be placed in the hands of interventionalists, thereby increasing the number of arteriovenous fistula providers, reducing wait times, and allowing the patient to avoid surgery. Moreover, current studies demonstrate that patients with percutaneous arteriovenous fistula experience improved time to arteriovenous fistula maturation. Yet, in order to realize the potential advantages of percutaneous arteriovenous fistula creation within our hemodialysis patient population, it is critical to select appropriate patients, ensure adequate patient and dialysis unit education, and provide sufficient instruction in percutaneous arteriovenous fistula cannulation and monitoring. In this White Paper by the American Society of Diagnostic and Interventional Nephrology, experts in interventional nephrology, surgery, and interventional radiology convened and provide recommendations on the aforementioned elements that are fundamental to a functional percutaneous arteriovenous fistula.

Rationale & Objective: Vascular access type (arteriovenous fistula [AVF] vs arteriovenous graft [AVG] vs central venous catheter [CVC]) associates with clinical outcomes in patients with end-stage kidney disease undergoing hemodialysis. Whether a similar association exists with outcomes after kidney transplantation is unknown. We hypothesized that AVGs would associate with worse outcomes, perhaps owing to persistent subclinical inflammation., Study Design: Retrospective cohort study., Setting & Participants: Using US registry data merged with electronic health records of a large dialysis organization (2006-2011), we selected patients receiving a first-ever kidney transplant after undergoing more than 30 days of hemodialysis., Exposure: Hemodialysis access used during the patient's last pretransplantation hemodialysis session., Outcomes: Patients were followed up from kidney transplantation for all-cause mortality, kidney allograft loss from any cause, and allograft loss not from death., Analytical Approach: Time-to-event analysis including Kaplan-Meier plots and Cox proportional hazards regression estimated cause-specific HRs and 95% CIs., Results: Among 9,291 patients who underwent kidney transplantation between 2006 and 2011, a total of 65.3% used an AVF, 20.4% used an AVG, and 14.3% used a CVC for hemodialysis before transplantation. Multivariable regression models adjusted for demographic variables, comorbid conditions, transplant characteristics, and laboratory parameters identified no independent associations between vascular access type and all-cause mortality (HR AVG , 1.13 [95% CI, 0.97-1.33]; HR CVC , 1.00 [95% CI, 0.83-1.21]). Similarly, AVG and CVC use were not independently associated with all-cause allograft loss compared with AVF use (HR AVG , 1.13 [95% CI, 1.00-1.28]; HR CVC , 1.12 [95% CI, 0.96-1.29]). CVC use was associated with 30% higher risk for allograft loss from causes other than death compared with AVF use (HR CVC , 1.30 [95% CI, 1.06-1.57]), but AVGs were not (HR AVG , 1.17 [95% CI, 0.98-1.39])., Limitations: Nonrandomized exposure leading to potential residual confounding., Conclusions: No association was found for AVG use before kidney transplantation with mortality, all-cause allograft loss, and allograft loss from all causes other than death, compared with AVF use. The association of CVC use with allograft loss from causes other than death requires further investigation., (© 2019 The Authors.)

Background: An arteriovenous fistula (AVF) is the recommended vascular access for hemodialysis (HD). Previous studies have not examined the resources and costs associated with creating and maintaining AVFs., Study Design: Retrospective observational study., Setting & Participants: Elderly US Medicare patients initiating hemodialysis therapy during 2010 to 2011., Predictor: AVF primary and secondary patency and nonuse in the first year following AVF creation., Outcomes: Annualized vascular access costs per patient per year., Results: Among patients with only a catheter at HD therapy initiation, only 54% of AVFs were successfully used for HD, 10% were used but experienced secondary patency loss within 1 year of creation, and 83% experienced primary patency loss within 1 year of creation. Mean vascular access costs per patient per year in the 2.5 years after AVF creation were $7,871 for AVFs that maintained primary patency in year 1, $13,282 for AVFs that experienced primary patency loss in year 1, $17,808 for AVFs that experienced secondary patency loss in year 1, and $31,630 for AVFs that were not used. Similar patterns were seen among patients with a mature AVF at HD therapy initiation and patients with a catheter and maturing AVF at HD therapy initiation. Overall, in 2013, fee-for-service Medicare paid $2.8 billion for dialysis vascular access-related services, ∼12% of all end-stage renal disease payments., Limitations: Lack of granularity with certain billing codes., Conclusions: AVF failure in the first year after creation is common and results in substantially higher health care costs. Compared with patients whose AVFs maintained primary patency, vascular access costs were 2 to 3 times higher for patients whose AVFs experienced primary or secondary patency loss and 4 times higher for patients who never used their AVFs. There is a need to improve AVF outcomes and reduce costs after AVF creation., (Copyright © 2018 The Authors. Published by Elsevier Inc. All rights reserved.)

Background: Vascular access practice is strongly associated with clinical outcomes. There is substantial international variation in the use of arteriovenous fistulas (AVFs) and grafts (AVGs), as well as AVF maturation time and location., Study Design: Prospective cohort study., Setting & Participants: Hemodialysis patients participating in the prospective Dialysis Outcomes and Practice Patterns Study (DOPPS) from the United States, Japan, and Europe/ANZ (Belgium, France, Germany, Italy, Spain, Sweden, United Kingdom, Australia, and New Zealand), including 3,850 patients receiving 4,247 new AVFs and 842 patients receiving 1,129 new AVGs in 2009 to 2015. AVF location trends were based on 38,868 AVFs recorded in DOPPS 1 to 5 cross-sections (1996-2015)., Predictors: Demographics, comorbid conditions, dialysis vintage, body mass index, facility percentage AVF use, median blood flow rate, and AVF location., Outcomes: AVF location; successful AVF/AVG use (≥30 days of continuous use); time-to-first successful AVF/AVG use (maturation)., Results: During DOPPS 1 to 5, the percentage of AVFs created in the lower arm was consistently ≥93% in Japan and 65% to 77% in Europe/ANZ, but in the United States, this value declined from 70% (DOPPS 1) to 32% (DOPPS 5). Patient characteristics associated with AVF location differed by region. Successful AVF use was 87% in Japan, 67% in Europe/ANZ, and 64% in the United States, whereas successful AVG use was 86%, 75%, and 78%, respectively. Successful AVF use was greater for upper- versus lower-arm AVFs in the United States, with little difference in Europe/ANZ and the opposite pattern in Japan. Median time until first successful AVF use was 10 days in Japan, 46 days in Europe/ANZ, and 82 days in United States; until first successful AVG use: 6, 24, and 29 days, respectively., Limitations: Potential measurement error related to chart data abstraction in multiple hemodialysis facilities., Conclusions: Large international differences exist in AVF location, predictors of AVF location, successful use of AVFs, and time to first AVF/AVG use, challenging what constitutes best practice. The large US shift from lower- to upper-arm AVFs raises serious concerns about long-term health implications for some patients and how policies and practices aimed at increasing AVF use have affected AVF placement location., (Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.)

This paper is part of the Clinical Trial Endpoints for Dialysis Vascular Access Project of the American Society of Nephrology Kidney Health Initiative. The purpose of this project is to promote research in vascular access by clarifying trial end points which would be best suited to inform decisions in those situations in which supportive clinical data are required. The focus of a portion of the project is directed toward arteriovenous access. There is a potential for interventional studies to be directed toward any of the events that may be associated with an arteriovenous access' evolution throughout its life cycle, which has been divided into five distinct phases. Each one of these has the potential for relatively unique problems. The first three of these correspond to three distinct stages of arteriovenous access development, each one of which has been characterized by objective direct and/or indirect criteria. These are characterized as: stage 1-patent arteriovenous access, stage 2-physiologically mature arteriovenous access, and stage 3-clinically functional arteriovenous access. Once the requirements of a stage 3-clinically functional arteriovenous access have been met, the fourth phase of its life cycle begins. This is the phase of sustained clinical use from which the arteriovenous access may move back and forth between it and the fifth phase, dysfunction. From this phase of its life cycle, the arteriovenous access requires a maintenance procedure to preserve or restore sustained clinical use. Using these definitions, clinical trial end points appropriate to the various phases that characterize the evolution of the arteriovenous access life cycle have been identified. It is anticipated that by using these definitions and potential end points, clinical trials can be designed that more closely correlate with the goals of the intervention and provide appropriate supportive data for clinical, regulatory, and coverage decisions., (Copyright © 2018 by the American Society of Nephrology.)

The population of patients with end-stage renal disease (ESRD) in the United States is progressively increasing, with hemodialysis (HD) as the major mode of renal replacement therapy. National guidelines recommend increasing the use of arteriovenous fistulae (AVF) in both incident and prevalent hemodialysis patients. Pre-operative vascular mapping prior to the surgical creation of an AVF is now considered standard of care and may be helpful in achieving these goals. This manuscript focuses on the advantages and limitations of the various imaging techniques currently available for vessel mapping including physical examination, ultrasonography, angiography (iodinated contrast vs. CO 2 ), and magnetic resonance angiography (MRA), with specific suggestions for clinical use., (© 2017 Wiley Periodicals, Inc.)

While central venous stenosis is a common consequence of protracted central venous catheter use, intracardiac device transvenous leads, and central venous instrumentation, the majority of patients who develop symptomatic central venous stenosis present with characteristic venous hypertension. However, some patients may develop an abnormal intracranial venous circulation and present with neurologic symptoms. This paper will summarize findings from case reports that describe the neurologic sequelae that can develop as a result of central venous stenosis/occlusion in end-stage renal disease patients with a functional arteriovenous access.

The majority of dialysis patients initiate dialysis using hemodialysis, rather than peritoneal dialysis (PD), although they may be candidates for either modality.Multiple factors account for this selection, including pre-dialysis education, physician familiarity with hemodialysis versus PD, and patient-related factors. This paper will discuss the various considerations by both providers and patients in the selection of PD as a modality.

Aim: To assess the association of measured gait speed with hemodialysis (HD) patients' hospitalization, in conjunction with, and apart from, recent fall history., Methods: Gait speed was measured by a standard protocol and falls during the past 12 mo were ascertained for a prevalent multi-center HD cohort (n = 668) aged 20-92. Hospitalization during the past 12 mo was identified in the patient's clinic records, and the first hospitalization after gait speed assessment (or the competing event of death) was identified in the 2013 United States Renal Data System Standard Analysis Files., Results: Slow gait speed, defined as < 0.8 m/s, characterized 34.7% of the patients, and 27.1% had experienced a recent fall. Patients with slow gait speed but without a history of recent falls were 1.79 times more likely to have been hospitalized during the past 12 mo (OR = 1.79, 95%CI: 1.11-2.88, P = 0.02), and patients with slow gait speed and a history of recent falls were over two times more likely to have been hospitalized (OR = 2.10, 95%CI: 1.19-3.73, P = 0.01), compared with patients having faster gait speed and no recent fall history. Prospective examination of gait speed/fall history status in relation to first hospitalization (or death) incurred by the end of follow-up December 31, 2011 also showed that slow gait speed was associated with these events in conjunction with a history of falls (HR = 1.54, 95%CI: 1.04-2.30, P = 0.03)., Conclusion: The International Task Force on Nutrition and Aging reported that gait speed is a powerful predictor for older adults of adverse outcomes such as hospitalization. In our data, gait speed--apart from, as well as in conjunction with, recent fall history--was associated with HD patients' hospitalization for multiple causes. Gait speed may be a sensitive health indicator among HD patients across the age spectrum.

Background: Falls among patients undergoing maintenance hemodialysis (HD) have significant consequences for quality of life and functional independence, morbidity, healthcare utilization and even mortality, but studies on the etiology of falls within large HD cohorts are limited., Methods: Falls during the past 12 months were ascertained for a prevalent multi-center HD cohort (n = 762) aged 20-92 years, and associations with demographic and treatment characteristics, comorbidities, cognitive function, prescribed medications, balance tests, frailty and depressive symptoms were assessed., Results: Falls were sustained by 28.4% of participants. In multivariable-adjusted analyses, participants classified as frail were over two times more likely to report falls [odds ratio (OR): 2.39, 95% confidence interval (CI): 1.22-4.71, P = 0.01], and participants with a CES-D score 18+ and/or prescribed antidepressants were over 80% more likely to be fallers (OR: 1.83, 95% CI: 1.23-2.74, P = 0.003) than were participants with a CES-D score <18 and no prescribed antidepressants., Conclusions: Frailty and depressed mood, factors that are potentially modifiable, are prominently associated with falls.

Background: It is unknown whether the selection of healthier patients for arteriovenous fistula (AVF) placement explains higher observed catheter-associated mortality among elderly hemodialysis patients., Methods: From the United States Renal Data System 2005-2007, we used proportional hazard models to examine 117 277 incident hemodialysis patients aged 67-90 years for the association of initial vascular access type and 5-year mortality after accounting for health status. Health status was defined as functional status at dialysis initiation and number of hospital days within 2 years prior to dialysis initiation., Results: Patients with catheter alone had more limited functional status (25.5 versus 10.8% of those with AVF) and 3-fold more prior hospital days than those with AVF (mean 18.0 versus 5.4). In the unadjusted model, the likelihood of death was higher for arteriovenous grafts (AVG) {Hazard ratio (HR) 1.20 [95% CI (1.16-1.25)], catheter plus AVF [HR 1.34 (1.31-1.38)], catheter plus AVG [HR 1.46 (1.40-1.52)] and catheter only [HR 1.95 (1.90-1.99)]}, compared with AVF (P < 0.001). The association attenuated -23.7% (95% CI -22.0, -25.5) overall (AVF versus all other access types) after adjusting for the usual covariates (including sociodemographics, comorbidities and pre-dialysis nephrology care) {AVG [HR 1.21 (1.17-1.26)], catheter plus AVF [HR 1.27 (1.24-1.30)], catheter plus AVG [HR 1.38 (1.32-1.43)] and catheter only [HR 1.69 (1.66-1.73)], P < 0.001}. Additional adjustment for health status further attenuated the association by another -19.7% (-18.2, -21.3) overall but remained statistically significant ., Conclusions: The observed attenuation in mortality differences previously attributed to access type alone suggests the existence of selection bias. Nevertheless, the persistence of an apparent survival advantage after adjustment for health status suggests that AVF should still be the access of choice for elderly individuals beginning hemodialysis until more definitive data eliminating selection bias become available.

Purpose: While vitamin D is critical for optimal skeletal health, it also appears to play a significant role in vascular homeostasis. This pilot study compared arteriovenous (AV) access outcomes following cholecalciferol supplementation compared to placebo in end-stage renal disease patients preparing to undergo AV access creation., Methods: A total of 52 adult hemodialysis patients preparing for arteriovenous fistula (AVF) creation were randomized to receive perioperative high-dose cholecalciferol versus placebo in this double-blind, randomized, placebo-controlled pilot study. The primary outcome was mean response to high-dose oral cholecalciferol versus placebo, and secondary outcome AV access maturation at 6 months. Logistic regression was used to assess the association between AV access maturation and baseline, posttreatment and overall change in vitamin D concentration., Results: A total of 45% of cholecalciferol-treated and 54% of placebo-treated patients were successfully using their AVF or arteriovenous graft (AVG) at 6 months (p=0.8). Baseline serum concentrations of 25(OH)D and 1,25(OH)2D did not differ between those who experienced AVF or AVG maturation and those who did not (p=0.22 and 0.59, respectively). Similarly, there was no relationship between AVF or AVG maturation and posttreatment serum 25(OH)D and 1,25(OH)2D concentration (p=0.24 and 0.51, respectively)., Conclusions: Perioperative high-dose vitamin D3 therapy does correct 25(OH)D level but does not appear to have an association with AV access maturation rates. Future research may include extended preoperative vitamin D3 therapy in a larger population or in certain subpopulations at high risk for AVF failure.

Background: The contribution of multiple retained nonfunctional arteriovenous grafts (AVGs) to the burden of chronic inflammation in chronic hemodialysis patients has not been well studied. Here, we sought to evaluate the association between plasma levels of C-reactive protein (CRP), interleukin-6 (IL-6), tumor necrosis factor alpha (TNF-alpha) and albumin and the number of retained nonfunctional AVGs., Methods: This cross-sectional study enrolled 91 prevalent patients undergoing in-center hemodialysis without evidence of infection or inflammation. A baseline blood sample was obtained at study enrollment. A general linear model (GLM) was used to compare levels of biomarkers of systemic inflammation across groups defined by the number of retained, nonfunctional AVGs., Results: A total of 43 patients had one or more retained thrombosed AVG and had significantly greater plasma log-CRP levels compared with patients without a previous AVG (P= 0.036), regardless of the current AV access type. Using a GLM, we found that for every additional retained thrombosed AVG, plasma log-CRP, log-IL-6 and TNF-alpha concentrations increased significantly by 0.30 mg/L (P= 0.011), 0.18 pg/mL (P= 0.046) and 0.72 pg/mL (P= 0.046), respectively, following adjustment., Conclusions: Hence, the severity of inflammation increases with the number of retained nonfunctional AVG's, suggesting that AVG accumulation may contribute to the cardiovascular morbidity and mortality associated with chronic inflammation in asymptomatic end-stage renal disease (ESRD) patients. Further study is indicated to determine whether patients with one or more thrombosed, retained AVG may benefit from periodic screening with CRP monitoring to identify those patients who may benefit from AVG resection.

Purpose: Low levels of physical activity among end-stage renal disease (ESRD) patients are associated with increased risk of hospitalization and mortality, and contributors to low activity levels are important to identify. Among hemodialysis (HD) patients, use of a central venous catheter (CVC) might impede physical activity due to factors such as infection or patient fear of catheter dislodgement., Methods: This Comprehensive Dialysis Study surveyed patients who had recently started regular dialysis. Physical activity level was ascertained using responses to the Human Activity Profile (HAP) provided by 1,458 HD participants. We examined the association of vascular access type with patients' scores on HAP subscales measuring self-care and leg effort, two dimensions that are especially important for daily living., Results: 32.6% of patients used an arteriovenous fistula (AVF), 11.5% used an arteriovenous graft, 51.8% used a CVC, and 4.1% used a CVC with another maturing access. Patients' self-care and leg effort scores differed by vascular access type and receipt of early nephrology care, and the mean self-care score of AVF users who received early care was similar to the mean score reported for healthy adults., Conclusions: Reported levels of self-care and leg effort activity were higher among incident HD patients using an AVF compared to those using a CVC. Future research should examine whether reinforcing the importance of regular physical activity in the pre-dialysis period, as well as wider early use of AVF in the HD population, may improve physical activity levels among ESRD patients.

Cardiovascular implantable electronic devices (CIEDs) are frequently utilized for management of cardiac dysrhythmias in patients with chronic kidney disease or end-stage renal disease receiving hemodialysis. The survival benefit from use of implantable cardioverter defibrillators in patients with CKD or ESRD is not as clear as in the general population, particularly when used for primary prevention of sudden cardiac death. Transvenous CIED leads are associated with central vein stenosis resulting in significant adverse consequences for existing or future arteriovenous access. Venous hypertension from CIED lead-related central vein stenosis is a challenging clinical problem and may require repeated percutaneous interventions, replacement of the CIED, or creation of alternative arteriovenous access. Infections associated with transvenous CIED leads are more frequent and associated with worse outcomes in patients with renal disease. Epicardial CIED leads or other nontransvenous devices may reduce complications of both central venous stenosis and endovascular infection in these vulnerable patients. Consensus recommendations are offered for avoidance and management of complications arising from the use of CIEDs and arteriovenous hemodialysis access., (© 2012 Wiley Periodicals, Inc.)

Although hemodialysis patients who initiate and maintain a permanent form of dialysis vascular access have improved all-cause and cardiovascular survival compared with those who use catheters, the presence of an arteriovenous fistula has been shown to have a short-term, adverse effect on cardiac function. Through its effect as a left-to-right extracardiac shunt, the arteriovenous fistula can increase cardiac workload substantially, and, in certain patients, result in a high-output state and resultant heart failure over time. Here we review the mechanisms by which dialysis arteriovenous access may promote the development of high-output cardiac failure in end-stage renal disease patients, describe risk factors for and the diagnosis of high-output heart failure, and suggest management strategies for patients who develop high-output heart failure., (Copyright © 2012 Elsevier Inc. All rights reserved.)

Background: Vitamin D deficiency contributes to secondary hyperparathyroidism, which occurs early in chronic kidney disease (CKD)., Objectives: We aimed to determine whether high-dose cholecalciferol supplementation for 1 y in early CKD is sufficient to maintain optimal vitamin D status (serum 25-hydroxyvitamin D [25(OH)D] concentration ≥30 ng/mL) and decrease serum parathyroid hormone (PTH). A secondary aim was to determine the effect of cholecalciferol on blood pressure and serum fibroblast growth factor-23 (FGF23)., Design: This was a double-blind, randomized, placebo-controlled trial. Forty-six subjects with early CKD (stages 2-3) were supplemented with oral cholecalciferol (vitamin D group; 50,000 IU/wk for 12 wk followed by 50,000 IU every other week for 40 wk) or a matching placebo for 1 y., Results: By 12 wk, serum 25(OH)D increased in the vitamin D group only [baseline (mean ± SD): 26.7 ± 6.8 to 42.8 ± 16.9 ng/mL; P < 0.05] and remained elevated at 1 y (group-by-time interaction: P < 0.001). PTH decreased from baseline only in the vitamin D group (baseline: 89.1 ± 49.3 to 70.1 ± 24.8 pg/mL; P = 0.01) at 12 wk, but values were not significantly different from baseline at 1 y (75.4 ± 29.5 pg/mL; P = 0.16; group-by-time interaction: P = 0.09). Group differences were more pronounced in participants with secondary hyperparathyroidism (group-by-time interaction: P = 0.004). Blood pressure and FGF23 did not change in either group., Conclusions: After 1 y, this oral cholecalciferol regimen was safe and sufficient to maintain serum 25(OH)D concentrations and prevent vitamin D insufficiency in early CKD. Furthermore, serum PTH improved after cholecalciferol treatment, particularly in patients who had secondary hyperparathyroidism.

Background: In an effort to improve identification and treatment of patients with chronic kidney disease (CKD), the National Kidney Foundation (NKF) developed the Kidney Disease Quality Outcomes Initiative (KDQOI) clinical practice guidelines, which include measurement of proteinuria among all patients with CKD who are not receiving chronic dialysis therapy. Encouraging dissemination and utilization of these guidelines may be enhanced by the development of performance measures. The question of whether adequate evidence exists to advocate for the measurement of proteinuria in CKD as a performance measure was explored., Methods: The US Preventive Services Task Force "chain of evidence" framework was used to guide evidence synthesis from the systematic review. Five questions were applied to specific links in the evidence chain: (1) Is there direct evidence that testing for proteinuria improves health outcomes? (2) What is the yield of testing, in terms of both accuracy and reliability of the test and the prevalence of undiagnosed proteinuria? (3) What adverse effects result from testing a person for proteinuria? (4) Does treatment of proteinuria as a result of testing provide an incremental benefit in health outcomes? and (5) What adverse effects result from treating a person for proteinuria? The systematic search specifically targeted meta-analyses and systematic reviews., Findings: The systematic review revealed no direct evidence that testing for proteinuria among patients with CKD reduced incidence of end-stage renal disease (ESRD). However, the strong links between testing, treatment, and outcome suggest a correlation between proteinuria testing and ESRD., Conclusions: Current evidence suggests that proteinuria testing (using the albumin-to-creatinine ratio [ACR]) among patients with CKD would be an appropriate health care quality performance measure for improving patient outcomes.

Purpose: Intimal hyperplasia (IH), a well-recognized cause of dialysis vascular access failure, is generally believed to be an acquired pathologic lesion. Recent data suggests that IH is present prior to AVF creation. We sought to determine whether pre-existing inflammation and oxidation co-exist with IH prior to their incorporation into an AVF conduit, as their presence may predispose the AVF to further IH following AVF creation., Methods: At the time of first AV access surgery, vein segments were collected from ten Stage 4 and 5 CKD patients undergoing AVF creation 6-12 months prior to anticipated dialysis initiation. Morphometry and immunohistochemistry was performed to detect inflammatory markers IL-6, TGF-ß1, and TNFa, and markers of DNA oxidative damage (8-Hydroxy-2'-deoxyguanosine [HNE]) and lipid peroxidation (4-Hydroxy-2-Nonenal [8OHdG])., Results: The degree of IH severity was variable. IL-6, TGF-ß1, and TNFa co-localized with a-smooth muscle actin prominently within the venous intima and media. Although more diffuse, HNE and 8OHdG were intensely expressed in parallel with the inflammatory markers. In spite of these findings, however, neither extant IH nor the intensity of inflammatory or oxidative markers were associated with primary or secondary AVF failure at 12 month follow-up., Conclusions: Not only does venous IH pre-exist, but inflammation and oxidation markers are present within veins used for the AVF conduit prior to its creation in CKD patients as early as one year before dialysis is commenced. Nevertheless, short and long-term AVF outcomes were not associated with the inflammatory or oxidative burden, suggesting the complexity of AVF dysfunction in humans with CKD.

Vitamin D deficiency is associated with a variety of skeletal, cardiometabolic, and immunologic co-morbidities that are present in chronic kidney disease (CKD). We performed a systematic review to investigate the effects of vitamin D supplementation, in the form of ergocalciferol or cholecalciferol, on various health outcomes in early CKD. Seventeen clinical trials were identified, only two of which were randomized, placebo controlled trials. The majority of studies supplementing with > 2,000 IU/day of cholecalciferol achieved optimal vitamin D status, whereas studies supplementing with ergocalciferol were less consistent. Studies varied widely in their effects on lowering serum parathyroid hormone concentrations. Few studies investigated effects of vitamin D treatment on other clinical health indicators in early CKD. Rigorous studies are necessary to investigate optimal vitamin D dosing strategies in early CKD for the maintenance of adequate vitamin D status, management of secondary hyperparathyroidism and improvement of non-skeletal related clinical outcomes.

Chymase, a serine protease found in mast cell granules, is released into the interstitium following injury or inflammation. Chymase is the primary ACE-independent pathway of angiotensin II formation, and also functions to activate TGF-beta and other promoters of extracellular matrix degradation, thereby playing a role in tissue remodeling. In the diseased kidney, chymase-containing mast cells markedly increase and their density correlates with tubulointerstitial fibrosis severity. Studies in humans support the pathologic role of chymase in diabetic nephropathy, while animal studies form the basis for the importance of increased chymase-dependent angiotensin II formation in progressive hypertensive, diabetic and inflammatory nephropathies. Moreover, humans with kidney disease express chymase in diseased blood vessels in concordance with significantly elevated plasma chymase levels. Conversely, specific chymase inhibitors attenuate angiotensin II production and renal fibrosis in animal models, suggesting their potential therapeutic benefit in human nephropathy, where chymase-containing mast cells accumulate and contribute to progressive disease.

Background: Vitamin D deficiency is highly prevalent among hemodialysis patients, but little data exist in support of an optimal repletion regimen., Objective: The objective was to ascertain the efficacy of weekly very-high-dose cholecalciferol (vitamin D(3)) in correcting vitamin D insufficiency and deficiency in patients with stage 5D chronic kidney disease., Design: We conducted a prospective, double-blind, randomized controlled pilot study that compared placebo with very high doses of oral cholecalciferol for 3 wk (200,000 IU/wk) in hemodialysis patients. We examined the rate of correction of vitamin D insufficiency or deficiency and the effect of treatment on markers of mineral metabolism and routine laboratory variables., Results: Twenty-seven subjects received placebo, and 25 received cholecalciferol. The majority (94%) of subjects had serum 25-hydroxyvitamin D [25(OH)D] concentrations <30 ng/mL. Study groups were similar with respect to baseline clinical characteristics, with the exception of hemoglobin concentrations, which were lower in the cholecalciferol-treated group (P < 0.04). At follow-up, 90.5% of subjects treated with cholecalciferol achieved serum 25(OH)D concentrations ≥30 ng/mL in contrast to 13.6% of the placebo group. There were no significant changes in serum calcium, phosphate, or intact parathyroid hormone during the study., Conclusion: Short-term, high-dose oral cholecalciferol treatment of vitamin D deficiency in hemodialysis patients appears to be effective and with no evidence of toxic effects. This trial was registered at clinicaltrials.gov as NCT00912782.

The underlying inflammatory component of chronic kidney disease may predispose blood vessels to intimal hyperplasia (IH), which is the primary cause of dialysis access failure. We hypothesize that vascular pathology and markers of IH formation are antecedent to arteriovenous (AV) fistula creation. Blood, cephalic, and basilic vein segments were collected from predialysis chronic kidney disease (CKD) patients with no previous AV access and patients with end-stage renal disease (ESRD). Immunohistochemistry was performed with antibodies against mast cell chymase, transforming growth factor-beta (TGF-β) and interleukin-6 (IL-6), which cause IH. Plasma chymase was measured by ELISA. IH was present in 91% of CKD and 75% of ESRD vein segments. Chymase was abundant in vessels with IH, with the greatest expression in intima and medial layers, and virtually absent in the controls. Chymase colocalized with TGF-β1 and IL-6. Plasma chymase concentration was elevated up to 33-fold in patients with CKD versus controls and was associated with increased chymase in vessels with IH. We show that chymase expression in vessels with IH corresponds with plasma chymase concentrations. As chymase inhibition attenuates IH in animal models, and we find chymase is highly expressed in IH lesions of patients with CKD and ESRD, we speculate that chymase inhibition could have therapeutic value in humans., (© 2011 Wiley Periodicals, Inc.)

Background: Circulating 25-hydroxyvitamin D [25(OH)D] concentration is inversely associated with peripheral arterial disease and hypertension. Vascular remodeling may play a role in this association, however, data relating vitamin D level to specific remodeling biomarkers among ESRD patients is sparse. We tested whether 25(OH)D concentration is associated with markers of vascular remodeling and inflammation in African American ESRD patients., Methods: We conducted a cross-sectional study among ESRD patients receiving maintenance hemodialysis within Emory University-affiliated outpatient hemodialysis units. Demographic, clinical and dialysis treatment data were collected via direct patient interview and review of patients records at the time of enrollment, and each patient gave blood samples. Associations between 25(OH)D and biomarker concentrations were estimated in univariate analyses using Pearson's correlation coefficients and in multivariate analyses using linear regression models. 25(OH) D concentration was entered in multivariate linear regression models as a continuous variable and binary variable (<15 ng/ml and ≥15 ng/ml). Adjusted estimate concentrations of biomarkers were compared between 25(OH) D groups using analysis of variance (ANOVA). Finally, results were stratified by vascular access type., Results: Among 91 patients, mean (standard deviation) 25(OH)D concentration was 18.8 (9.6) ng/ml, and was low (<15 ng/ml) in 43% of patients. In univariate analyses, low 25(OH) D was associated with lower serum calcium, higher serum phosphorus, and higher LDL concentrations. 25(OH) D concentration was inversely correlated with MMP-9 concentration (r = -0.29, p = 0.004). In multivariate analyses, MMP-9 concentration remained negatively associated with 25(OH) D concentration (P = 0.03) and anti-inflammatory IL-10 concentration positively correlated with 25(OH) D concentration (P = 0.04)., Conclusions: Plasma MMP-9 and circulating 25(OH) D concentrations are significantly and inversely associated among ESRD patients. This finding may suggest a potential mechanism by which low circulating 25(OH) D functions as a cardiovascular risk factor.

Background: Few US patients with kidney failure start treatment on peritoneal dialysis (PD) despite its potential survival, quality of life, and cost-saving benefits. We investigated patient awareness of PD and variables associated with PD selection, including dialysis unit ownership and geographic area., Methods: In a cohort study, incident dialysis patients identified by the Centers for Medicare and Medicaid Services (CMS) and included in the United States Renal Data System (USRDS) were surveyed from 2005 to 2007 for the USRDS Comprehensive Dialysis Study. Participants reported whether PD had been discussed with them before they started regular treatment for kidney failure, and initial dialysis modality was verified in the USRDS patient registry., Results: The proportion of patients in our study cohort who reported that PD had been discussed with them (61%) was higher than in previous surveys, but only 10.9% of informed patients initiated PD. With patient demographic and clinical characteristics controlled for, the proportion of informed patients who started PD differed substantially across large dialysis organizations. Substantial variation in selection of PD was also evident among patients starting dialysis in the 18 end-stage renal disease Network areas., Conclusions: Despite patients' early awareness of PD as a treatment option, PD selection was low in this national cohort. Factors associated with PD selection merit continued study as CMS seeks to improve quality and cost-effectiveness of kidney patient care.

Background: The Centers for Medicare & Medicaid Services (CMS) established a national goal of 66% arteriovenous fistula (AVF) use in prevalent hemodialysis (HD) patients for the current Fistula First Breakthrough Initiative. The feasibility of achieving the goal has been debated. We examined contemporary patterns of AVF use in prevalent patients to assess the potential for attaining the goal by dialysis facilities and their associated End-Stage Renal Disease Networks in the United States., Study Design: Observational study., Setting & Participants: US dialysis facilities with a mean HD patient census of 10 or more during the 40-month study period, January 2007-April 2010., Outcomes & Measurements: Mean changes in facility-level AVF use and percentage of facilities achieving the 66% prevalent AVF goal within the United States and each network., Results: Mean prevalent AVF use within dialysis facilities increased from 45.3% to 55.5% (P < 0.001) in the United States, but varied substantially across regions. The percentage of facilities achieving the 66% AVF use goal increased from 6.4% to 19.0% (P < 0.001). During the 40 months, 35.9% of facilities achieved the CMS goal for at least 1 month. On average, these facilities sustained mean use ≥66% for 12.9 ± 11.7 (SD) months. Case-mix and other facility characteristics explained 20% of the variation in proportion of facility patients using an AVF in the last measured month, leaving substantial unexplained variability., Limitations: This analysis is limited by the absence of facility case-mix data over time, and the national scope of the initiative precludes use of a comparison group., Conclusions: Achieving the CMS goal of 66% prevalent AVF use is feasible for individual dialysis facilities. There is a need to decrease regional variation before the CMS goal can be fully realized for US HD facilities., (Copyright © 2010 National Kidney Foundation, Inc. All rights reserved.)

There is substantial geographic variability in both incident and prevalent arteriovenous fistula (AVF) use among patients with ESRD. This study examined the degree to which these variations associate with poverty in the county of a patient's treatment center. We performed a cross-sectional study including 28,135 patients treated by 1127 hemodialysis centers in five ESRD networks (16 states) between June 1, 2005 and May 31, 2006. We used the 2000 U.S. Census to categorize county-level poverty and ascertained incident AVF use from the Medicare CMS 2728 form. We calculated the 30-month slope of change in AVF prevalence from monthly facility reports collected between 2003 and 2005. More than 33% of treatment centers were located in high-poverty counties. County poverty inversely associated with incident AVF use (P for trend = 0.001). In contrast, substantial increases in prevalent AVF rates from 30.9 to 38.6% (P < 0.001) among treatment centers did not associate with county poverty (P = 0.9519). In conclusion, the concentration of poverty in the county where a treatment is located associates with incident AVF use by patients with ESRD but not with subsequent improvement in AVF use among prevalent patients. These results suggest that the Medicare ESRD program may mitigate poverty effects on AVF use.

Background: Arteriovenous fistula (AVF) use is reported to differ among racial and gender groups. We sought to identify risk factors associated with incident AVF and whether racial and gender differences in AVF use persist after controlling for these factors., Methods: We evaluated 28,712 incident adult hemodialysis patients (age ≥ 18) from five ESRD networks starting dialysis between June 1, 2005 and May 31, 2006. Data were obtained from the Center for Medicaid and Medicare Services 2728 form., Results: Incident AVF use was reported for 11% of black and 12% of white patients [OR = 0.89 (95% CI: 0.83, 0.96)], and for 9% of females and 13% of males [OR = 0.66 (0.62-0.71)]. After adjusting for facility clustering, blacks were as likely as whites to use an AVF [OR = 1.00 (0.92-1.09)], while gender differences persisted [OR = 0.64 (0.59-0.69)]. Compared to patients with no renal care prior to dialysis initiation, incident AVF use was 16-fold greater among those with ≥ 12 months of nephrology care [OR = 15.99 (13.25-19.29)], 9-fold greater among those with 6-12 months of care [OR = 9.00 (7.45-10.88)] and 7-fold greater among those with at least 6 months of care [OR = 7.13 (5.73-8.88)]., Conclusion: Racial, but not gender, differences in incident AVF use were eliminated after accounting for clustering within facilities., (Copyright © 2010 S. Karger AG, Basel.)

Background: Early detection of chronic kidney disease (CKD) is sub-optimal among the general population and among high risk patients. The prevalence and impact of major CKD risk factors, diabetes (DM) and hypertension (HTN), on CKD documentation among managed care populations have not been previously reported. We examined this issue in a Kaiser Permanente Georgia (KPG) CKD cohort., Methods: KPG enrollees were included in the CKD cohort if they had eGFRs between 60 and 365 days apart that were <90 ml/min during 1999-2006. The current analysis is restricted to participants with eGFR 10-59 ml/min/1.73 m2. CKD documentation was defined as a presenting diagnosis of CKD by a primary care physician or nephrologist using ICD-9 event codes. The association between CKD documentation and DM and HTN were assessed with multivariate logistic regression models., Results: Of the 50,438 subjects within the overall KPG CKD cohort, 20% (N = 10,266) were eligible for inclusion in the current analysis. Overall, CKD diagnosis documentation was low; only 14.4% of subjects had an event-based CKD diagnosis at baseline. Gender and types 2 diabetes interacted on CKD documentation. The prevalence of CKD documentation increased with the presence of hypertension and/or type 2 diabetes, but type 2 diabetes had a lower effect on CKD documentation. In multivariate analysis, significant predictors of CKD documentation were eGFR, hypertension, type 2 diabetes, congestive heart failure, peripheral artery disease, statin use, age and gender. CKD documentation was lower among women than similarly affected men., Conclusion: Among patients with an eGFR 10-59, documentation of CKD diagnosis by primary and subspecialty providers is low within a managed care patient cohort. Gender disparities in CKD documentation observed in the general population were also present among KPG CKD enrollees.

The population of patients with ESRD in the United States is progressively increasing, with hemodialysis (HD) as the major mode of renal replacement therapy. The National Kidney Foundation's Dialysis Outcomes and Quality Initiative and the Fistula First Initiative recommend increasing the use of arteriovenous fistulae (AVF) in both incident and prevalent hemodialysis patients. One measure proposed is the use of pre-operative vascular mapping to assess the upper extremities for the presence of suitable vessels prior to the surgical creation of an AVF among both pre-dialysis CKD and ESRD patients on HD. This article aims to review the literature on vascular mapping, including the various techniques; their advantages and disadvantages; and whether they help to maximize the AVF creation rate as well as increase the use of AVF in the HD population.