KDOQI Clinical Practice Guideline for Vascular Access: 2019 Update.

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

KDOQI Clinical Practice Guideline for vascular access: 2019 update

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

Medicare Costs Associated With Arteriovenous Fistulas Among US Hemodialysis Patients.

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.

Definitions and End Points for Interventional Studies for Arteriovenous Dialysis Access.

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.

Bioengineered human acellular vessels for dialysis access in patients with end-stage renal disease: two phase 2 single-arm trials.

BACKGROUND: For patients with end-stage renal disease who are not candidates for fistula, dialysis access grafts are the best option for chronic haemodialysis. However, polytetrafluoroethylene arteriovenous grafts are prone to thrombosis, infection, and intimal hyperplasia at the venous anastomosis. We developed and tested a bioengineered human acellular vessel as a potential solution to these limitations in dialysis access. METHODS: We did two single-arm phase 2 trials at six centres in the USA and Poland. We enrolled adults with end-stage renal disease. A novel bioengineered human acellular vessel was implanted into the arms of patients for haemodialysis access. Primary endpoints were safety (freedom from immune response or infection, aneurysm, or mechanical failure, and incidence of adverse events), and efficacy as assessed by primary, primary assisted, and secondary patencies at 6 months. All patients were followed up for at least 1 year, or had a censoring event. These trials are registered with ClinicalTrials.gov, NCT01744418 and NCT01840956. FINDINGS: Human acellular vessels were implanted into 60 patients. Mean follow-up was 16 months (SD 7·6). One vessel became infected during 82 patient-years of follow-up. The vessels had no dilatation and rarely had post-cannulation bleeding. At 6 months, 63% (95% CI 47-72) of patients had primary patency, 73% (57-81) had primary assisted patency, and 97% (85-98) had secondary patency, with most loss of primary patency because of thrombosis. At 12 months, 28% (17-40) had primary patency, 38% (26-51) had primary assisted patency, and 89% (74-93) had secondary patency. INTERPRETATION: Bioengineered human acellular vessels seem to provide safe and functional haemodialysis access, and warrant further study in randomised controlled trials. FUNDING: Humacyte and US National Institutes of Health.

HeRO graft versus lower extremity grafts in hemodialysis patients with long standing renal failure.

BACKGROUND: The role of the HeRO graft in central venous pathology has been defined in the literature and clinically. There have been two publications or abstracts that have compared the patency rates and outcomes of this graft to the lower extremity graft. AIM: The outcomes of both publications leads to an algorithm suggested by the author in determining which procedure should be used for specific patients. METHODS: Both papers trend to show that lower extremity grafts have improved patency rates when compared to the HeRO device in the upper extremity. DISCUSSION: The author will use these data to demonstrate that in younger patients and in patients with low morbidity and mortality, salvaging the upper extremity area for access may show that the HeRO device provides benefit for these patients.

Prospective multicenter study with a 1-year analysis of a new vascular graft used for early cannulation in patients undergoing hemodialysis.

OBJECTIVE: More than 85% of patients with end-stage renal disease start dialysis through a tunneled dialysis catheter (TDC) for long periods while their arteriovenous fistula or vascular access graft (arteriovenous graft [AVG]) matures. Because TDCs are associated with a high risk of complications, including death and infection, use of an AVG that can be cannulated safely immediately after implantation may reduce morbidity in these patients by allowing earlier TDC removal. We report a prospective multicenter study of a new early-cannulation AVG (Gore ACUSEAL Vascular Graft; W. L. Gore & Associates, Flagstaff, Ariz). METHODS: Patients requiring creation of a prosthetic vascular access for hemodialysis were enrolled between July 2010 and February 2012 and observed for 12 months. Data were collected on the patients' baseline characteristics; location, position, loss of patency, and revisions of prior AVGs; dialysis sessions using the AVG; and major adverse events related to graft implantation or cannulation. Cumulative and primary unassisted graft patency rates were calculated. A subgroup analysis compared outcomes in patients in whom the AVG was first cannulated within 72 hours after implantation with outcomes in patients in whom the initial cannulation was performed >21 days postoperatively. RESULTS: The population of this study was formed by 138 patients who received an ACUSEAL graft. During follow-up, 17 patients died and the AVG was abandoned in 27. The median value for follow-up was 360 days for all patients (variance 15,387). The overall mean time to initial cannulation was 15 days, with 54 grafts (40%) first cannulated within 72 hours after graft implantation and 33 grafts first cannulated >21 days afterward. The reason for late cannulation in some patients was dependent on the implanting surgeon's decision and the surgeon's personal experience with early cannulating grafts. The 1-year overall cumulative patency rate was 79% (95% confidence interval, 71%-85%); the primary unassisted patency rate was 35% (95% confidence interval, 27%-44%). Adverse events included 6 hematomas (two of which were related to cannulation and occurred 107 and 169 days, respectively, after AVG implantation), 15 graft infections, and 15 cases of steal syndrome requiring intervention. Patients in the early- and later-cannulation groups had similar characteristics and no significant differences in rates of cumulative or primary unassisted patency or adverse events. CONCLUSIONS: This study demonstrated that the new, early-cannulation AVG graft can be cannulated soon after implantation without a significant difference in patency and complication rates compared with rates associated with standard cannulation of expanded polytetrafluoroethylene grafts in the literature. This new AVG may allow early removal or avoidance of TDC use in patients undergoing hemodialysis, potentially reducing or eliminating the number of days of catheter-dependent dialysis, but further studies will be needed to demonstrate this potential.

Arteriovenous graft configuration in hemodialysis: does it matter?

PURPOSE: The current guidelines for arteriovenous graft (AVG) configuration in hemodialysis state the following sequence: forearm loop, upper arm straight or curved and upper arm looped. These recommendations are based upon literature from the 1980s. Modern patient demographics and patient treatment algorithms, i.e., the Fistula First initiative (FFI), have greatly changed the current practice environment. It is not clear if these changes alter the outcomes of AVGs based upon configuration. METHODS: The most recent National Kidney Foundation Kidney Disease Outcomes Quality Initiative (NKF/K-DOQI) guidelines for vascular access were reviewed. Articles cited to support recommendations for AVG configuration were evaluated. The following search terms: arteriovenous graft configuration, access configuration, PTFE configuration in hemodialysis and straight, looped, curved graft configuration were used to search PubMed, Ovid, Medline and Google scholar. Articles that included data comparing AVG configuration were included. Citations within those articles were examined for publications overlooked in the initial search. Four articles and one abstract were reviewed and separated into pre- and post-FFI groups. RESULTS: Pre-FFI articles demonstrate superiority of forearm looped AVG over straight forearm grafts. Post-FFI, the literature suggests that primary patency, thrombosis and steal are not affected by configuration and location, although looped configuration may have superior secondary patency. CONCLUSIONS: The available literature is mixed regarding the effect of configuration on AVG outcomes. Current studies illustrate the effect may be limited and that larger randomized controlled trials are necessary to draw firm conclusions. Regardless, adequate inflow and an appropriately sized outflow vein are paramount for optimal graft performance.

Patient compliance limits the efforts of quality improvement initiatives on arteriovenous fistula maturation.

OBJECTIVE: Our institutional quality-improvement (QI) initiative instituted a well-defined office follow-up schedule after arteriovenous fistula (AVF) creation, including an office visit within 30 days, fistulogram within 40 days, if indicated, and a second office visit within 55 days. In addition, a patient liaison contacted patients and dialysis units to improve follow-up. The purpose of this study was to determine the effect of the QI initiative on patient compliance and overall time to AVF permission to cannulate. METHODS: We performed a retrospective review of patients undergoing first-time radiocephalic, brachiocephalic, and basilic vein transposition creation before the QI initiative (pre-QI group: January to April 2012) and during the QI period (QI group: January to April 2013). Categoric data were compared using χ(2) analysis, and nominal data were compared using the Student t-test. RESULTS: We reviewed 198 first-time AVF creations in patients (57% male) with a mean age of 61 years. Demographics and comorbidities between the pre-QI and QI groups were similar. Compliance with the first 30-day postoperative appointment increased significantly after the QI initiative, from 48% in the pre-QI group to 65% in the QI group (P = .015). Yet, the QI initiative did not maintain an effect on the subsequent follow-up checkpoints. No statistical difference was identified for compliance with fistulogram within 40 days of access creation (pre-QI, 12% vs QI, 25%; P = .093) or for compliance with the 55-day postoperative appointment (pre-QI, 33% vs QI, 23%; P = .457). Both checkpoints demonstrated a very high noncompliance rate. Accordingly, the mean time to permission to cannulate was 88 days for both the pre-QI and QI groups, with a failure to mature rate of 22% for the pre-QI group and 21% for the QI group (P = .816). CONCLUSIONS: The QI initiative significantly increased the number of patients complying with the first 30-day follow-up appointment after AVF access creation. However, patient compliance with a timely fistulogram and the second follow-up appointment was poor and not influenced by the QI initiative, limiting the functional effect of the QI initiative on the time to AVF permission to cannulate.

The Venous Window Needle Guide, a hemodialysis cannulation device for salvage of uncannulatable arteriovenous fistulas.

BACKGROUND: Arteriovenous fistulas (AVFs) are recommended for hemodialysis access when possible. A noncannulatable but otherwise well functioning AVF leads to prolonged catheter dependency and frustration for the patient and the renal health care provider team. Difficult cannulation patients include obese individuals in whom cannulation sites are too deep, and others with vein segments that are short, tortuous, or otherwise difficult to palpate. The Venous Window Needle Guide for Salvage of AV Fistulae (SAVE) trial was designed to evaluate the efficacy and safety of the Venous Window Needle Guide (VWING; Vital Access Corp, Salt Lake City, Utah) device for salvage of such noncannulatable AVFs that are otherwise functional. METHODS: The SAVE study included patients with an established and otherwise mature AVF, in whom an additional procedure would otherwise be necessary to establish reliable cannulation. The VWING is a single-piece titanium device that allows repeated access of an AVF through a single puncture site (buttonhole technique). Inclusion criteria included mature AVFs 6.0 to 15.0 mm in depth with multiple failed attempts at cannulation or where the access could not be palpated. The devices were implanted subcutaneously and sutured to the anterior wall of the mature fistula. Study end points were reliable and successful cannulation and avoidance of adverse events during the 6-month follow-up, implant technical success, and clinical cannulation success. RESULTS: Enrollment included 54 patients at 11 trial sites with implantation of 82 VWING devices. Body mass index was 26 to 50 (median, 36), 40 (74%) patients were female, and age was 17 to 84 (median, 59) years. Forty (74%) individuals were diabetic. Thirty-three (61%) patients were white, 16 (30%) black, and 10 (18%) patients were Hispanic, Pacific Islander, or Native American. Three patients were excluded from data analysis for reasons unrelated to the device. Successful AVF access was achieved using the VWING in 49 (96%) of the 51 patients evaluated. The rate of device-related serious adverse events was 0.31 per patient-year; each event was resolved leaving the AVF functional. The rates of sepsis and study-related interventions were 0.04 and 0.65 per patient-year, respectively. There were no study-related deaths. One device was removed because of infection. The AVF survival rate at 6 months was 100%. The total number of study days was 9497 and the estimated number of device cannulations was 4238. CONCLUSIONS: The VWING was safe and effective in facilitating AVF cannulation for patients with an otherwise mature but noncannulatable fistula. Successful AVF access was achieved using the VWING in 49 (96%) of the 51 patients evaluated. The AVF survival rate at 6 months was 100%.

A comparison between the HeRO graft and conventional arteriovenous grafts in hemodialysis patients.

Venous stenosis and occlusion are a major cause of vascular access dysfunction and failure. The HeRO Graft bypasses occlusion and traverses stenosis with outflow directly into the central venous circulation. A randomized, multicenter study was conducted to evaluate the efficacy and safety of the HeRO Graft relative to conventional AV grafts. The design was to enroll 143 patients in a 2:1 randomization ratio between HeRO and conventional AV control groups. Data on 72 subjects (52 HeRO Graft and 20 AV graft controls) were obtained. The HeRO Graft and control cohorts were comparable in baseline characteristics. Adequacy of dialysis, bacteremia rates, and adverse events were consistent between groups. Twelve month Kaplan-Meier estimates for primary and secondary patency rates were 34.8% and 67.6% in the HeRO Graft cohort, and 30.6% and 58.4% in the control cohort. There was no statistical difference in terms of patency between groups. The rates of intervention were 2.2/year for HeRO Graft and 1.6/year for the control (p = 0.100). Median days to loss of secondary patency was 238 for HeRO Graft versus 102 for the control (p = 0.032). The HeRO Graft appears to provide similar patency, adequacy of dialysis, and bacteremia rates to those of conventional AV grafts.

Elderly patients with CKD--dilemmas in dialysis therapy and vascular access.

The population of elderly patients with end-stage renal disease (ESRD) is growing rapidly worldwide. The high prevalence of comorbidities, limited life expectancy and complex quality of life issues associated with this population pose substantial challenges for clinicians in terms of clinical decision-making and providing optimal care. The first dilemma encountered in the management of an elderly patient with ESRD is deciding whether to initiate renal replacement therapy and, if so, selecting the most-suitable dialysis modality. Planning vascular access for haemodialysis is associated with additional challenges. Several clinical practice guidelines recommend an arteriovenous fistula, rather than a central venous catheter or arteriovenous graft, as the preferred access for maintenance haemodialysis therapy. However, whether this recommendation is applicable to elderly patients with ESRD and a limited life expectancy is unclear. Selection and planning of the most appropriate vascular access for an elderly patient with ESRD requires careful consideration of several factors and ultimately should lead to an improvement in the patient's quality of life.

Outcomes comparison of HeRO and lower extremity arteriovenous grafts in patients with long-standing renal failure.

OBJECTIVE: The Hemodialysis Reliable Outflow (HeRO) graft is becoming a recognized alternative to lower extremity arteriovenous grafts (LEAVGs) as an option for patients who have exhausted traditional upper extremity access; however, which should be applied preferentially is unclear. METHODS: A retrospective review of LEAVG and HeRO implants from January 2004 to August 2010 was performed. Patient demographics, medical history, procedural data, and outcomes were evaluated. RESULTS: Within the time periods, 60 HeROs were placed in 59 patients and 22 LEAVGs were placed in 21 patients. Demographics were similar between the two groups for many factors; however, the patients who underwent HeRO placement had significantly higher body mass index compared with the LEAVG group. Mean follow-up was 13.9 months for the HeRO group and 11.9 months for the LEAVG group. The HeRO patients underwent a mean of 6.3 previous tunneled dialysis catheter insertions and 3.1 previous AVG/arteriovenous fistula placements. The LEAVG patients underwent placement of a mean of 4.1 previous tunneled dialysis catheters and 2.6 previous AVG/arteriovenous fistulas. The principal difference was the number of interventions to maintain patency, which was 2.21 per year in the HeRO group and 1.17 per year in the AVG group (P = .003) Secondary patency at 6 months was 77% for the HeRO patients and 83% for the LEAVG patients (P = .14). The HeRO and LEAVG groups had no difference in infection rate per 1000 days (0.61 vs 0.71; P = .77) or mortality rate (22% vs 19% respectively; P = .22) at 6 months. CONCLUSIONS: In access challenged patients, LEAVG and HeRO offer similar rates of secondary patency, infection, and all-cause mortality. The LEAVG required fewer interventions to maintain patency, and the HeRO maintains the benefit of utilizing the upper extremity site of venous drainage. In our practice, we prefer the HeRO to LEAVG, especially in patients with peripheral arterial disease and in the obese population, because it preserves lower extremity access options.

A multi-center, dose-escalation study of human type I pancreatic elastase (PRT-201) administered after arteriovenous fistula creation.

PURPOSE: To explore the safety and efficacy of PRT-201. METHODS: Randomized, double-blind, placebo-controlled, single-dose escalation study of PRT-201 (0.0033 to 9 mg) applied after arteriovenous fistula (AVF) creation. Participants were followed for one year. The primary outcome measure was safety. Efficacy measures were the proportion with intra-operative increases in AVF outflow vein diameter or blood flow ≥25% (primary), changes in outflow vein diameter and blood flow, AVF maturation and lumen stenosis by ultrasound criteria and AVF patency. RESULTS: The adverse events in the PRT-201 group (n=45) were similar to those in the placebo group (n=21). There were no differences in the proportion with ≥25% increase in vein diameter or blood flow, successful maturation or lumen stenosis. There was no statistically significant difference in primary patency between the dose groups (placebo n=21, Low Dose n=16, Medium Dose n=17 and High Dose n=12). In a subgroup analysis that excluded three participants with early surgical failures, the hazard ratio (HR) for primary patency loss of Low Dose compared with placebo was 0.38 (95% CI 0.10-1.41, P=0.15). In a Cox model, Low Dose (HR 0.27, 95% CI 0.04-0.79, P=0.09), white race (HR 0.17, 95% CI 0.03-0.79, P=0.02), and age <65 years (HR 0.25, CI 0.05-1.15, P=0.08) were associated (P<0.10) with a decreased risk of primary patency loss. CONCLUSIONS: PRT-201 was not different from placebo for safety or efficacy measures. There was a suggestion for improved AVF primary patency with Low Dose PRT-201 that is now being studied in a larger clinical trial.

HeRO Vascular Access Device.

Chronic hemodialysis via a tunneled dialysis catheter (TDC) is associated with a high incidence of infectious complications and increased mortality and, therefore, should only be considered when all other options for vascular access are exhausted. The Hemoaccess Reliable Outflow (HeRO) Vascular Access Device (Hemosphere, Inc., Minneapolis, MN) is an alternative to the TDC. Early results suggests that the infectious complications are significantly less for the HeRO device when compared to the TDC, and the secondary patency for the device approximates that for prosthetic accesses. The device can be successfully placed in >90% of catheter-dependent patients. Chronic hemodialysis via the HeRO Device is preferable to TDC use.

New biological solutions for hemodialysis access.

Since Scribner described the first prosthetic chronic dialysis shunt in 1961, the surgical techniques and strategies to maintain vascular access have improved dramatically. Today, hundreds of thousands of patients worldwide are treated with some combination of native vein fistula, synthetic vascular graft, or synthetic semipermanent catheter. Despite significantly lower efficacy compared with autologous fistulae, the basic materials used for synthetic shunts and catheters have evolved surprisingly slowly. The disparity between efficacy rates and concomitant maintenance costs has driven a strong campaign to decrease the use of synthetic grafts and catheters in favor of native fistulae. Whether arguing the benefits of Fistula First or "Catheter Last," the fact that clinicians are in need of an alternative to expanded polytetrafluoroethylene (ePTFE) is irrefutable. The poor performance of synthetic materials has a significant economic impact as well. End-stage renal disease (ESRD) accounts for approximately 6% of Medicare's overall budget, despite a prevalence of about 0.17%. Of that, 15%-25% is spent on access maintenance, making hemodialysis access a critical priority for Medicare. This clinical and economic situation has spawned an aggressive effort to improve clinical care strategies to reduce overall cost and complications. While the bulk of this effort has historically focused on developing new synthetic biomaterials, more recently, investigators have developed a variety of cell-based strategies to create tissue-engineered vascular grafts. In this article, we review the evolution of the field of cardiovascular tissue engineering. We also present an update on the Lifeline™ vascular graft, an autologous, biological, and tissue-engineered vascular graft, which was the first tissue-engineered graft to be used clinically in dialysis patients.

Preclinical results of a prosthetic, early-stick graft with functional endothelium.

PURPOSE: The purpose of this study was to evaluate the NanoVasc Vascular Graft in comparison with a marketed expanded polytetrafluoroethylene (ePTFE) graft, both in vitro and in vivo. The graft was evaluated for use as both a bypass and arteriovenous (AV) access graft. Early-stick capabilities and patency were the primary end points evaluated. METHODS: Third party, independent laboratories completed mechanical testing, biocompatibility, and preclinical data collection. An ovine carotid artery interposition model and a canine femoral AV access model were used to evaluate 5-mm and 6-mm internal diameter sizes, respectively. RESULTS: There was no statistical difference in either model between the NanoVasc and ePTFE grafts with respect to patency. Time to hemostasis after cannulation with a 16-gauge needle was achieved ~10 times faster with the NanoVasc graft (mean time 27 seconds) compared with ePTFE. Histological analysis demonstrated functional endothelialization (nitric oxide expression), positive wound healing (cellular infiltration into the wall of the graft), and hemocompatibility of the NanoVasc graft. CONCLUSIONS: The NanoVasc Vascular Graft is a strong candidate as a bypass and AV access graft. Its early-stick capabilities and patency rates are an attractive feature in comparison with current AV access grafts.

Renal artery stent infection and pseudoaneurysm management.

BACKGROUND: Infection of a renal artery stent and pseudoaneurysm is extremely uncommon, with four reports in the literature. We present a fifth case and the complex management resulting in kidney salvage. METHODS AND RESULTS: A 56-year-old female underwent right renal artery stenting for hypertension. Postoperatively, she developed methicillin-resistant Staphylococcus infection, treated with antibiotics. Eight-month follow-up duplex ultrasound revealed a right renal artery pseudoaneurysm just distal to the stent. Computed tomography angiography (CTA) showed 2.8 cm proximal and 4.2 cm distal mycotic aneurysms. Antibiotics and planning angiogram were prescribed. A Chevron incision and duodenal kocherization were employed. The aorta below the superior mesenteric artery and below the renal vein was mobilized, as were the right renal artery and vein, hepatic artery, and saphenous vein. Following heparinization, the aorta was cross-clamped, as was the right renal artery at the hilum. The kidney was infused with cold saline. The renal artery stent was explanted, and aneurysmectomy was performed. The renal artery ostium was oversewn. A renal artery to hepatic artery saphenous vein bypass was fashioned, and patency was confirmed with intraoperative duplex ultrasound. Postoperatively, creatinine was normal, renal scan showed the right kidney to be functional, and duplex ultrasound showed a patent bypass graft. The patient was discharged on postoperative day 11 on long-term antibiotics. Eight-month follow-up duplex and CTA showed a patent bypass and durable repair. CONCLUSION: Renal artery stent infection with pseudoaneurysm is rare and can be diagnosed with duplex ultrasound. Renal salvage can be obtained but requires stent removal and autologous bypass grafting.

Should fistulas really be first in the elderly patient?

BACKGROUND: The Kidney Disease Outcomes and Quality Initiative (K/DOQI) has developed guidelines from available data suggesting that arteriovenous fistulas (AVF) be performed in the majority of patients. Patient demographics were not included nor suggested in their recommendations. The purpose of this study is to analyze the outcomes of elderly patients, age greater than 70, undergoing first-time permanent access surgery. METHODS: A retrospective review of consecutive patients undergoing new, first time access procedures from January 2005 through December 2005 was performed. Patients with previous attempts at permanent Arteriovenous (AV) access were removed from analysis. Standard statistical methods were used and patency was determined with Kaplan-Meier curves. RESULTS: One hundred and sixty eight patients underwent first time AVF, 48 of whom were older than 70 years of age. Comparing elderly patients to younger ones, the 12 month primary assisted patency was 35% and 67%, respectively (p=0.002) and secondary patency was 36% and 67%, respectively (p=0.004). Of the 48 elderly patients, 48% had died in the subsequent follow up period as compared to just 20% of the 120 patients younger than 70. The 18-month survival for the elderly group was 50% versus 74% for the younger patients (p=0.004). Of the elderly group who died, the average time to death was 13.1 months and only 8 AVF were able to be accessed. Similar intervention rates per year were seen in both groups. DISCUSSION: With an aging population, more patients older than 70 are being evaluated for permanent vascular access. This group poses a difficult dilemma for surgeons attempting to adhere to K/DOQI guidelines. In light of the increased mortality and decreased patency of AVF, this data questions which form of permanent access should be first-line treatment in this subgroup of patients. CONCLUSION: This data suggest in the elderly patients, autogenous fistulas may not be the best option for this set of patients.

Initial experience and outcome of a new hemodialysis access device for catheter-dependent patients.

OBJECTIVE: The effects of a new long-term subcutaneous vascular access device were studied in access-challenged patients who were poor candidates for fistulas or grafts due to venous obstruction. Bacteremia rates, patency, and function of the Hemodialysis Reliable Outflow (HeRO) Vascular Access Device (Hemosphere Inc, Minneapolis, Minn) were evaluated. METHODS: The HeRO device consists of a 6-mm expanded polytetrafluoroethylene graft attached to a 5-mm nitinol-reinforced silicone outflow component designed to bypass venous stenoses and enter the internal jugular vein directly, providing continuous arterial blood flow into the right atrium. The HeRO device was studied in a multicenter clinical trial to test the hypothesis that access-challenged patients would experience a statistically significant reduction in bacteremia rates compared with a tunneled dialysis catheter (TDC) literature control of 2.3/1000 days. HeRO-related bacteremia rates, adequacy of dialysis, patency, and adverse events were analyzed. RESULTS: The HeRO device was implanted in 36 access-challenged patients who were followed for a mean 8.6 months (9931 HeRO days). The HeRO-related bacteremia rate was 0.70/1000 days. All HeRO-related bacteremias occurred during the bridging period when a TDC was still implanted before HeRO graft incorporation. HeRO adequacy of dialysis (mean Kt/V) was 1.7. HeRO primary patency was 38.9%, and secondary patency was 72.2%. CONCLUSIONS: In access-challenged patients, a statistically significant reduction in HeRO-related bacteremia was noted compared with TDC literature. The device had similar function and patency compared with conventional arteriovenous graft literature.