The Pivotal Multicenter Trial of Ultrasound-Guided Percutaneous Arteriovenous Fistula Creation for Hemodialysis Access

Research on comprehensive analysis of patient comfort and complication rate using haemodialysis indwelling needles in AVF puncture in haemodialysis treatment

Traditional needles for haemodialysis access can cause complications and discomfort. Indwelling needles may have advantages, but their efficacy needs to be investigated. Our study sought to compare the safety and efficacy of indwelling needles to traditional needles for haemodialysis access. A single-center retrospective study at the Pingyang County Hospital of Traditional Chinese Medicine included 70 haemodialysis patients. The intervention group used indwelling needles, whereas the control group used traditional needles. The rate of complications, limb mobility, blood chemistry, puncture success rates, operation times, haemostasis times, pain and comfort scores, and internal fistula failure rates were all compared. Overall, complication rates were slightly higher in the control group, but not statistically significant. Both groups improved their limb mobility and blood chemistry, but there were no significant differences. The intervention group had significantly higher puncture success rates (88.4% vs. 80.0%), shorter operation times (65.4 vs. 72.3 seconds), and faster haemostasis times (23.7 vs. 28.2 seconds) than the control group. Patients in the intervention group experienced less pain (3.7 vs. 4.2) and more comfort (8.1 vs. 7.5). The intervention group had slightly lower internal fistula failure rates (2.9% vs. 5.7%), but the difference was not statistically significant. Indwelling needles appear to improve puncture efficiency and patient comfort during hemodialysis.

Cost-effectiveness analysis of endovascular vs surgical arteriovenous fistula creation in the United States

OBJECTIVE

In the United States, an estimated $2.8 billion annually is spent on vascular access and its complications. Endovascular arteriovenous fistula (endoAVF) creation is a novel, minimally invasive alternative to traditional surgical AV fistula (sAVF) creation in ≤60% of patients. Although cost effective in single-payer systems, the clinical and financial impact of endoAVF in the United States remains uncertain.

METHODS

We constructed a decision tree followed by a probabilistic cohort state-transition model to study the cost effectiveness of endoAVF vs sAVF creation. We conducted a systematic review to obtain input parameters including technical success, maturation, patency, and utility values. We derived costs from the Medicare 2022 fee schedule and from the literature. We used a 5-year time horizon, an annual discount rate of 3% for costs and utilities (measured in quality-adjusted life-years [QALYs]), and the common willingness-to-pay threshold of $50,000. One-way and Monte Carlo probabilistic sensitivity analyses were performed varying technical success, patency, reintervention, cost, and utility parameters.

RESULTS

In the base-case scenario, endoAVF ($30,129 average per-person costs, 2.19 QALYs gained, 65% patent at 5 years) was not cost effective compared with sAVF ($12.987 average per-person costs, 2.11 QALYs gained, 66% patent at 5 years), generating an incremental cost-effectiveness ratio of $227,504 per QALY gained. In one-way sensitivity analyses, endoAVF becomes cost effective when the initial cost of sAVF creation exceeds endoAVF by ≥$600 (eg, if endoAVF creation costs ≤$3000 relative to the base-case sAVF cost of $3600), the additional QALYs gained from endoAVF exceeds 0.12 QALYs/year (eg, 0.81 QALYs gained/year from endoAVF compared with base-case sAVF 0.69 QALYs/year), the endoAVF maturation rate is >90% (base case 78%), or the sAVF maturation rate is <65% (base case 78%). Probabilistic sensitivity analysis demonstrated that sAVF remained the optimal strategy in 71% of iterations.

CONCLUSIONS

EndoAVF is not cost effective compared with sAVF when modeling 5-year outcomes. The main driver of sAVF remaining cost effective is the four times higher up-front cost for endoAVF creation, as well as a relatively low additional increase in quality of life for endoAVF. It will be important to establish how the endoAVF learning curve contributes to upfront costs and, given the annual cost attributed to vascular access nationally, a randomized controlled trial is warranted.

Evaluating patient perspectives of endovascular created arteriovenous fistulas for dialysis access (EndoAVF)

BACKGROUND

Patient reported experience measures are contemporary quality indicators that focus on evaluation of healthcare delivery processes. While surgical arteriovenous fistulas (otherAVF) are preferred for haemodialysis vascular access, fears about surgery and complications often result in refusal/delays. A new technique of endovascular arteriovenous fistula creation (EndoAVF) has been developed and as part of it's ongoing introduction into our unit, the patient perspective was felt critical to its evaluation. The Vascular Access Questionnaire (VAQ) provides a mechanism for identifying and scoring perceptions in this setting.

METHOD

Patients who had previously undergone EndoAVF formation were approached to undertake the VAQ as part of a service evaluation of their experience. In addition to the components of the VAQ, data questions relating to the patient's perception of their access were gathered. Results were compared with a matched historical cohort of surgically created fistulas (otherAVF) patients.

RESULTS

Patient satisfaction and self-reported ease of use with EndoAVF were high. Overall VAQ scores were similar between the EndoAVF and the surgically created cohort. Functionally, there was no significant difference in perception of their fistula by patients, irrespective of them being created surgically or radiologically.

CONCLUSION

Although numbers in this report are small limiting exploration of preserved inherent heterogeneity, we provide a useful initial patient reported experience and perspectives on comparative functional use of radiologically and surgically created AVFs. As real world experience gathers, future larger cohorts with adequate sampling may allow exploration of patient reported experiences and outcome measures.

Multidisciplinary working group: key role for percutaneous endovascular AV fistula program. Point of view

Chronic kidney disease is a progressive condition that affects more than 10% of the general population worldwide. Hemodialysis is the most common therapeutic option for kidney failure, which develops in around one out of 1000 individuals in the general population. Hemodialysis needs a vascular access to connect to the extracorporeal machine. In the last few years percutaneous endovascular arterio-venous fistula technique has been increasingly employed with very promising results. Several advantages have been demonstrated in comparison to the standard surgical creation of an arteriovenous fistula. The percutaneous endovascular arterio-venous fistula technique requires multidisciplinary team work. In our practice, we have organized a multidisciplinary team that includes nephrologists, play a key role, interventional radiologists, vascular surgeons, anesthesiologists, and dialysis nurses. Procedural outcomes and feedback received from patients and family members are evaluated periodically in order to improve results. Nephrologists are involved in each step of the management of the percutaneous endovascular arterio-venous fistula: selection, mapping, creation, and follow up. Patient empowerment, education and involvement is required at each step. A dedicated training program, involving patients and the caregiver team is therefore needed. Additional research is required to confirm the benefit of the multidisciplinary team management in end-stage kidney disease patients.

Percutaneous Creation of Hemodialysis Fistulas

Non-surgical, percutaneous, or endovascular hemodialysis arteriovenous creation represent an evolution of access creation away from traditional surgical fistulas. These fistulas are additional to surgical alternatives and published studies with the two commercially available devices suggest positive outcomes in terms of technical success, maturation, functionality, and patency. Relevant published studies are presented, and other considerations related to these new devices/procedures are also summarized.

Dialysis Access-Associated Steal Syndrome and Management

Dialysis-associated steal syndrome (DASS) occurs in 1-8% of hemodialysis patients with arteriovenous (AV) access. Major risk factors include use of the brachial artery for access creation, female sex, diabetes, and age > 60 years. DASS carries severe patient morbidity including tissue or limb loss if not recognized and managed promptly, as well as increased mortality. Diagnosis of DASS requires a directed history and physical exam supported by non-invasive testing. Prior to definitive therapy, detailed arteriography, fistulography, and flow measurements are performed to delineate underlying etiologies and guide management. To optimize success, DASS treatment should be individualized according to access location, underlying vascular disease, flow dynamics, and provider expertise. Possible causes of DASS include extremity inflow or outflow arterial occlusive disease, high AV access flow rate, and reversal of distal extremity arterial blood flow; DASS may also exist without any of the prior features. Depending on the DASS etiology, various endovascular and/or surgical interventions should be considered. Regardless, in the majority of patients presenting with DASS, access preservation can be achieved.

Early clinical experience and comparison between percutaneous and surgical arteriovenous fistula

BACKGROUND

Percutaneous arteriovenous fistula (pAVF) has been recently developed as an alternative to surgical AVF (sAVF). We report our experience with pAVF in comparison with a contemporaneous sAVF group.

METHODS

Charts of all 51 patients with pAVF performed at our institution were analyzed retrospectively, in addition to 51 randomly selected contemporaneous patients with sAVF (2018-2022) with available follow-up. Outcomes of interest were (i) procedural success rate, (ii) number of maturation procedures required, (iii) fistula maturation rates, and (iv) rates of tunneled dialysis catheter (TDC) removal. For patients on hemodialysis (HD), sAVF and pAVF were considered mature when the AVF was used for HD. For patients not on HD, pAVF were considered mature if flow rates of ≥500 mL/min were documented in superficial venous outflow; for sAVF, documentation of maturity based on clinical criteria was required.

RESULTS

Compared patients with sAVF, patients with pAVF were more likely to be male (78% vs 57%; P = .033) and less likely to have congestive heart failure (10% vs 43%; P < .001) and coronary artery disease (18% vs 43%; P = .009). Procedural success was achieved in 50 patients with pAVF (98%). Fistula angioplasties (60% vs 29%; P = .002) and ligation (24% vs 2%; P = .001) or embolization (22% vs 2%; P = .002) of competing outflow veins were more frequently performed on patients with pAVF. The surgical cohort had more planned transpositions (39% vs 6%; P < .001). When all maturation interventions were combined, pAVF required more maturation procedures, but this was not statistically significant (76% vs 53%; P = .692). When planned second-stage transpositions were excluded, pAVF had a statistically significant higher rate of maturation procedures (74% vs 24%; P < .001). Overall, 36 pAVF (72%) and 29 sAVF (57%) developed mature fistulas. This difference, however, was not statistically significant (P = .112). At the time of AVF creation, 26 patients with pAVF and 40 patients with sAVF were on HD, all through use of a TDC. Catheter removal was recorded in 15 patients with pAVF (58%) and 18 patients with sAVF (45%) (P = .314). The mean time until TDC removal in pAVF group was 146 ± 74 days, compared with 175 ± 99 in the sAVF group (P = .341).

CONCLUSIONS

Compared with sAVF, rates of maturation after pAVF seem to be similar, but this result may be related to the higher intensity of maturation procedures and patient selection. An analysis of appropriately matched patients will assist in elucidating the possible role of pAVF vis-a-vis sAVF.

Options for Dialysis and Vascular Access Creation

End-stage kidney disease (ESKD) affects nearly 800,000 patients in the United States. The choice of peritoneal dialysis (PD) versus hemodialysis (HD) should be patient centric. An ESKD Life-Plan is crucial with the goal of creating the right access, for the right patient, at the right time, for the right reason. Complex access should be considered when straightforward access options have been exhausted. Evolving techniques such as percutaneous access for HD and PD should be further investigated. Shared decision-making and palliative care is an essential part of the care of patients with CKD and ESKD..

A systematic review aggregated data and individual participant data meta-analysis of percutaneous endovascular arteriovenous fistula

OBJECTIVE

To assess the short-term and mid-term safety and efficacy of percutaneous endovascular arteriovenous fistula (pAVF) creation.

METHODS

A systematic search was implemented corresponding to the PRISMA 2020 and the PRISMA for individual participant data (IPD) systematic reviews 2015. Aggregated data from the included studies were obtained and meta-analyzed regarding both the overall pAVF efficacy and the comparison of pAVF with surgical AVF (sAVF). We performed a two-stage IPD meta-analysis for studies comparing pAVF and sAVF regarding primary and secondary patency. Primary end points included primary patency, secondary patency, and functional cannulation.

RESULTS

Eighteen studies with 1863 patients were included. The overall pAVF, primary patency, secondary patency, functional cannulation and abandonment rates were 54.01% (95% confidence interval [CI], 40.69-66.79), 87.27% (95% CI, 81.53-91.42), 79.94% (95% CI, 65.94-89.13), and 15.58% (95% CI, 7.77-28.79), respectively. The overall pAVF, technical success, maturation, reintervention per person-years and mean time to maturation rates were 97.08% (95% CI, 95.66-98.04), 82.13% (95% CI, 71.64-89.32), 0.80 (95% CI, 0.34-1.47), and 58 days (95% CI, 36.64-92.82), respectively. Secondary patency and pAVF abandonment rates where the only end points were WavelinQ and Ellipsys displayed statistically significant differences of 81.36% (95% CI, 76.15-85.65) versus 92.12% (95% CI, 87.94-94.93) and 32.54% (95% CI, 22.23-44.87) versus 11.13% (95% CI, 4.82-23.65). An IPD meta-analysis of hazard ratios for primary and secondary patency between pAVF and sAVF were 1.27 (95% CI, 0.61-2.67) and 1.25 (95% CI, 0.87-1.80), favoring sAVF. Statistically significant difference between pAVF and sAVF were solely depicted for steal syndrome relative risk of 5.91 (95% CI, 1.12-31.12) and wound infections relative risk of 4.19 (95% CI, 1.04-16.88). Plotting of pAVF smoothed hazard estimate displayed an upsurge in the probability of primary patency failure at 1 month after the intervention.

CONCLUSIONS

Although we failed to identify statistically significant differences between pAVF and sAVF regarding any of the primary end points, pAVF displayed a decreased risk for steal syndrome and wound infection. Although both the Ellipsys and WavelinQ devices displayed satisfactory secondary patency rates, Ellipsys demonstrated a statistically significant improved rate compared with WavelinQ. Additionally, and despite the borderline statistically insignificant inferior reintervention rate displayed by WavelinQ, one in three WavelinQ pAVFs resulted in abandonment. The introduction of pAVF as a treatment modality calls for standardized definition adjustment and improvement.

Endovascular Arteriovenous Fistula Creation-Review of Current Experience

Functioning vascular access is an essential element for life-saving hemodialysis therapy. A surgically-created arteriovenous fistula has been considered the best option for many years. Recently, two manufacturers developed systems for percutaneous/endovascular creation of an arteriovenous fistula (WavelinQ and Ellipsys). We provide a review of the available experience with these systems and discuss advantages and disadvantages.

Adapting a Dialysis Service for Delivery of Percutaneous Arteriovenous Fistulas

The percutaneous arteriovenous fistula (pAVF) is an exciting and novel addition to the vascular access options available to patients with end-stage kidney disease who require dialysis. Early clinical results have been promising, with high rates of maturation and low rates of reintervention. To successfully adapt an existing hemodialysis service to include the provision of pAVF formation, it is essential to identify and align the interests of key clinical and nonclinical stakeholders. Only through strong collaboration can the service be supported. The authors provide a comprehensive overview of the planning fundamentals required, including the referral pathway, screening and clinical assessment, and practical procedural elements and considerations, as well as follow-up requirements such as cannulation, fistula surveillance, and maintenance. Key staffing requirements are highlighted, including those pertaining to vascular US screening and dialysis nurse training. A broad and structured planning approach ensures that the entire network of key stakeholder interests is included and provides a strong foundation for a compelling business plan to attract the necessary funding and managerial support for the service. The authors present a systematic framework of the essential considerations necessary to facilitate the planning, funding, and ultimately delivery of a successful pAVF service. Online supplemental material is available for this article. ^©RSNA, 2022.

Sistema percutáneo de creación de fistulas arteriovenosas en pacientes con hemodiálisis: nuestra experiencia inicial

Introducción: La fístula arteriovenosa es considerada el acceso de elección para los pacientes en hemodiálisis; en los últimos años emerge una alternativa a la creación quirúrgica de esta: la fístula arteriovenosa endovascular. Esta nueva tecnología conlleva un método menos agresivo y sin cirugía.Objetivo: Describir los datos preliminares de nuestra unidad tras la implantación de este sistema novedoso, así como su implicación para enfermería.Material y Método: Análisis descriptivo retrospectivo de las FAV-endovasculares realizadas a cinco pacientes mediante técnica percutánea. Se consideraron las características de los pacientes, de las FAV-endovasculares realizadas y la dificultad para su punción (escala EVA).Resultados: La edad media fue de 63 (47-77) años, 100% hombres, dializándose con catéter tunelizado, a 4 de los pacientes se les había realizado al menos una fístula arteriovenosa quirúrgica sin éxito. La creación de la FAV-endovascular fue exitosa en 4 de los 5 pacientes, todas con localización radio-radial. No hubo complicaciones durante el procedimiento. De las 4 FAV-endovasculares 3 precisaron intervención endovascular posterior para su maduración. La media de tiempo de maduración 4,5 (4-5) meses; las 4 continuaron permeables al año.Puntuada por 9 enfermeras experimentadas, la mediana de dificultad fue: punción inicial: 7, a partir del mes: 5 y comparada con las FAV quirúrgicas: 5.Conclusiones: La FAV-endovascular supuso un procedimiento mínimamente invasivo con menor impacto para los pacientes, elevado éxito inicial, pero precisó intervención endovascular posterior para su maduración. La dificultad para la punción fue más elevada inicialmente. La ausencia de cicatriz  supuso realizar una exploración más exhaustiva.

Percutaneous endovascular arteriovenous fistula: A systematic review and meta-analysis

Objective

Currently, percutaneous endovascular creation of arteriovenous fistula (AVF) shows excellent outcomes. However, few systematic research evidence to support clinical decision making on the benefit of endovascular AVF is available. The purpose of this study was to evaluate the efficacy and safety of endovascular AVF (endoAVF) in patients with renal failure.

Methods

We searched the Medline, Embase, Cochrane Library, and ClinicalTrials.gov databases for studies on endovascular or endovascular versus surgery for the creation of AVF. Two reviewers independently selected studies and extracted data. A systematic review and meta-analysis were performed by Review Manager 5.4 software (Revman, The Cochrane Collaboration, Oxford, United Kingdom) and Stata 15.0 (Stata Corp, College Station, TX, United States).

Results

A total of 14 case series and 5 cohort studies, with 1,929 patients, were included in this study. The technique success was 98.00% for endoAVF (95% CI, 0.97–0.99; I² = 16.25%). There was no statistically significant difference in 3 cohort studies between endovascular and surgical AVF for procedural success (OR = 0.69; 95% CI, 0.04–11.98; P = 0.80; I² = 53%). The maturation rates of endoAVF were 87.00% (95% CI, 0.79–0.93; I² = 83.96%), and no significant difference was observed in 3 cohort studies between the 2 groups (OR = 0.73; 95% CI, 0.20–2.63; P = 0.63; I² = 88%). Procedure-related complications for endoAVF was 7% (95% CI, 0.04–0.17; I² = 78.31%), and it did not show significant difference in 4 cohort studies between the 2 groups (OR = 1.85; 95% CI, 0.37–9.16; P = 0.45; I² = 59%).

Conclusion

The endovascular creation of AVF is potentially effective and safe. These important data may provide evidence to support clinicians and patients in making decisions with endovascular AVF. But further research is great necessary due to lack of randomized controlled studies.

Outcomes of Wrist-Access Deep Venous Embolization Following Percutaneous Fistula Creation: A Two-Year Single Center Experience

PURPOSE

During percutaneous arteriovenous (pAVF) fistula creation, deep venous embolization is recommended to encourage superficial venous flow development. The safety of crossing adjacent to the newly formed fistula from wrist venous access has not been established. The purpose of this study was to evaluate the safety and efficacy of antegrade deep venous embolization after creation of the pAVF.

MATERIALS

A retrospective analysis was performed of all procedural data related to pAVF creation using the Wavelinq device from October 2019 to November 2021. Patient data from the hospital information systems were collected where the venous access for fistula creation was from the wrist-access (ulnar or radial vein) and where deep venous embolization was performed after forming the fistula and crossing adjacent to the anastomosis. Thirty-nine patients were identified.

RESULTS

Twenty pAVFs were created from wrist ulnar vein access and 19 from radial vein access. The accessed veins were used for embolization of the brachial veins central to the newly created anastomosis. No pAVFs were lost by crossing adjacent to the anastomotic area to perform deep venous embolization at time of creation. There were no major complications, specifically bleeding, infection, pseudoaneurysm formation. Rates of minor complications consisted of two coil migrations to the right atrium requiring uneventful retrieval (5%). Follow-up ultrasound data showed no evidence of delayed complications.

CONCLUSION

In this single center experience crossing alongside the anastomosis of a newly formed percutaneous fistula from an antegrade venous approach was safe with no risk of loss of the pAVF.

Percutaneous Hemodialysis Fistula Creation

Two devices have been recently introduced to European Union and North American clinical practice that allow for percutaneous creation of autogenous hemodialysis fistulas (pAVF). Although there are similarities between the devices, there are many differences. Adoption of either or both technologies by an interventionalist may be determined by the individual's comfort with the device. Importantly, current and future outcomes will shape acceptance and use of these devices. This review focuses on the similarities and differences of each device, the procedures, published outcomes to date and their interpretation and other clinical considerations towards initiation of a successful pAVF program.

Long Term Results from The Pivotal Multicenter Trial of Ultrasound Guided Percutaneous Arteriovenous Fistula Creation for Hemodialysis Access

PURPOSE

To report the five-year results from the Pivotal Multicenter Trial of Ultrasound Guided Percutaneous Arteriovenous Fistula (pAVF) Creation for Hemodialysis Access.

MATERIALS AND METHODS

Retrospective review of 107 intent-to-treat (ITT) patients from the pivotal trial provided a long-term follow-up population (LTP) of 85 patients followed a median 50 months (range 12-60). Data evaluated in the LTP group were fistula maturation and use, secondary procedures, and complications. Kaplan-Meier analysis of primary, primary assisted, cumulative patency, and functional patency (time from two-needle to abandonment) were performed for the ITT population.

RESULTS

In the LTP 99% (84/85) of fistulas were mature with 99% (78/79) of patients requiring hemodialysis using their pAVF. Sustained fistula use (two-needle cannulation at prescribed rate, 2/3 sessions) was achieved in 92% (78/85) of patients, with seven patients never using their pAVF because not on dialysis (n=4), peritoneal dialysis (n=2), and refusing to use fistula (n=1). Fistula maintenance was required in 31.8% (27/85) of patients and included fistula dysfunction (21.2%), thrombosis (5.9%), cannulation injury (12.9%), and arm swelling (4.7%). The number of procedures performed per patient per year (PPPY) to maintain function and patency was 0.32 (91/288) for years 2-5. The cumulative patency was 89.5%, 88.4%, 88.4%, 85.6%, and 82.0% years 1-5, respectively. The functional patency was 91.8% at the end of the study. There were no major complications related to pAVF during long-term follow-up CONCLUSION: Percutaneous fistulae have provided clinically effective and durable access for hemodialysis with low complications. Continued use and evaluation of pAVF is warranted.

Endovascular Versus Surgical Arteriovenous Fistulas: A Systematic Review and Meta-analysis

Rationale & Objective

To facilitate the process of dialysis for patients with kidney failure, an arteriovenous fistula (AVF) is created using either a surgical or percutaneous approach. We sought to compare the efficacy and procedural outcomes in creating an AVF percutaneously using Ellipsys (Avenu Medical) or WavelinQ (Becton Dickinson Medical) with surgery in all patients with kidney failure requiring a permanent AVF for dialysis.

Study Design

Systematic review and meta-analysis.

Setting & Study Populations

All patients requiring a permanent AVF for dialysis.

Selection Criteria for Studies

We included studies that compared either the Ellipsys device or WavelinQ directly with surgery to create an AVF for long-term dialysis.

Data Extraction

Two reviewers independently reviewed the studies and extracted the data. Conflicts were resolved with a discussion and approval from the senior author.

Analytical Approach

Fixed-effects or random-effects models were used to pool the fixed sizes and 95% CIs based on the level of heterogeneity.

Results

There was no statistically significant difference observed between surgical AVF and endovascular AVF when comparing the primary outcomes of procedural success (OR = 1.44; 95% CI, 0.35, 5.88; P = 0.61; I2 = 0%), complications (OR = 0.28; 95% CI, 0.06, 1.46; P = 0.13; I2 = 69%), and the secondary outcomes of interest that included follow-up time (mean difference [MD] = -17.71; 95% CI, -189.53, 154.12; P = 0.84; I2 = 94%), failure rate (OR = 1.03; 95% CI, 0.21, 5.13; P = 0.97; I2 = 85%), and time to 2-needle cannulation (MD = -5.40; 95% CI, -38.88, 28.08; P = 0.75; I2 = 0%). However, a statistically significant difference was seen among the 2 groups for procedural time (MD = -54.25; 95% CI, -59.78, -48.71; P < 0.001; I2 = 98%), number of interventions needed to maintain patency (OR = 1.73; 95% CI, 1.22, 2.45; P < 0.01; I2 = 94%), and primary patency rate (OR = 0.34; 95% CI, 0.23,0.52; P < 0.001; I2 = 0%).

Limitations

The total number of studies included in this review was limited, with 3 of the 4 included studies being retrospective and only 1 being prospective. There was a lack of heterogeneity and randomization.

Conclusions

Percutaneous fistula creation using Ellipsys or WavelinQ is a unique and safe alternative with outcomes comparable to surgery. Future studies are needed, including observational studies in current clinical practice, to evaluate the efficacy and outcomes of endovascular AVF creation in clinical populations.

Devices and Techniques for Percutaneous Creation of Dialysis Arteriovenous Fistulas

Dialysis treatment for chronic kidney disease was first developed by Dr. Willem Kolff in 1943, and its availability began to grow in 1962 after which it has become a mainstay treatment for patients with chronic kidney disease. It is estimated that, in 2021, 15% of adults in the United States (∼37 million people) have chronic kidney disease, of which 661,000 individuals have renal failure, and 468,000 individuals require dialysis. There have been several advancements in dialysis treatment since its advent, most notably the creation of arteriovenous fistulas (AVFs) for venous access in 1966. In recent years, the U.S. Food and Drug Administration approved two new devices for AVF creation using a percutaneous approach. These are the WavelinQ (Becton Dickinson, New Jersey) and the Ellipsys (Avenu Medical, California) endovascular AVF (endoAVF) devices that use radiofrequency and thermal technologies, respectively, to create the AVF. Since the introduction of these technologies, several studies have shown that they are safe and effective, with favorable durability and low rate of serious adverse events. In this article, we will discuss these two devices and the techniques used for percutaneous creation of dialysis AVF as an alternative to traditional open surgical techniques.

Leveraging real-world evidence for determining performance goals for medical device studies

Performance goals are numerical target values pertaining to effectiveness or safety endpoints in single-arm medical device clinical studies. Typically, performance goals are determined at the planning stage of the investigational study under consideration based on summarized outcome information from existing relevant clinical trials. In recent years, there is a growing interest in leveraging real-world evidence in medical product development. In this article, we introduce a new method for proposing performance goals by leveraging real-world evidence. The method applies entropy balancing to address possible patient dissimilarities between the study's target patient population and existing real-world patients, and can take into account operation differences between clinical studies and real-world clinical practice. An illustrative example is provided to demonstrate how to implement the proposed method for performance goal determination while leveraging real-world evidence.

Percutaneous arteriovenous fistula creation

The first percutaneous systems used to create an arteriovenous fistula for hemodialysis were approved by the US Food and Drug Administration in 2018 and included the Ellipsys and WavelinQ devices. Early results and longer-term studies of these catheter-based devices suggest that they offer important benefits and potentially improved outcomes in patients with appropriate anatomy. The deep communicating vein in the cubital fossa and its relationship to the proximal radial artery or proximal ulnar artery are key vascular elements of both systems. The devices differ significantly in technical design, energy source, imaging requirements, procedure times, catheters, access vessel sites, and techniques. We review the two approved percutaneous arteriovenous fistula devices, including technical considerations, selecting the appropriate patient, postoperative evaluation, interventions, outcomes, potential complications, and cannulation issues.

Feasibility of Creation of an Endovascular Arteriovenous Fistula in Patients Undergoing Preoperative Vascular Mapping

Background

The first endovascular arteriovenous fistula (endoAVF) device (WavelinQ), a novel percutaneous technique of AVF creation, was approved by the Food and Drug Administration in 2018 and has been placed in a small number of United States patients on hemodialysis. It is unknown how often patients with advanced CKD have vascular anatomy suitable for WavelinQ creation. The goal of this study was to determine the proportion of patients with vascular anatomy suitable for WavelinQ creation and to assess patient characteristics associated with such suitability.

Methods

All patients referred for vascular access placement at a large academic medical center underwent standardized preoperative sonographic vascular mapping to assess suitability for an AVF. During a 2-year period (March 2019 to March 2021), we assessed the suitability of the vessels for creation of WavelinQ. We then compared the demographic characteristics, comorbidities, and vascular mapping measurements between patients who were or were not suitable for WavelinQ.

Results

During the study period, 437 patients underwent vessel mapping. Of these, 51% of patients were eligible for a surgical AVF, and 32% were eligible for a WavelinQ AVF; 63% of those suitable for a surgical AVF were also suitable for a WavelinQ AVF. Patients with a vascular anatomy suitable for WavelinQ were younger (age 55±15 versus 60±14 years, P=0.01) but similar in sex, race, diabetes, hypertension, coronary artery disease, and peripheral artery disease.

Conclusions

Among patients with CKD with vascular anatomy suitable for a surgical AVF, 63% are also suitable for a WavelinQ endoAVF. Older patients are less frequently suitable for WavelinQ.

Research Priorities for Percutaneous Arteriovenous Fistula Creation in Patients with End-Stage Renal Disease: Proceedings and Recommendations from a Multidisciplinary Research Consensus Panel

Recently developed endovascular techniques to create percutaneous arteriovenous fistulas are an alternative to surgical arteriovenous fistula creation, although there is currently a lack of high-level evidence regarding their creation, maturation, utilization, and long-term function. Recognizing this, the Society of Interventional Radiology Foundation sponsored a Research Consensus Panel and Summit for the prioritization of a research agenda to identify and address the gaps in current knowledge.

Multicenter European real-world utilization of VasQ anastomotic external support device for arteriovenous fistulae

OBJECTIVE

To evaluate the outcomes of arteriovenous fistulae (AVF), created with VasQ external support device under standard clinical practice across three vascular access clinics.

METHODS

This multinational, retrospective study evaluated prospectively collected clinical outcomes of both forearm and upper arm brachiocephalic AVF (BCAVF) created using the VasQ device. Fifty-one AVF patients were pooled from three different vascular access centers in Germany, Italy, and Spain. Postprocedure outcomes were assessed by flow measurement with ultrasound examination in all centers. Primary failure, usability, patency, and intervention rates during the study period were evaluated.

RESULTS

Fifty-one VasQ devices were implanted during 37 forearm (36 radiocephalic and 1 ulnar-basilic AVF) and 14 BCAVF procedures. The study population comprised mostly males (73%) and Caucasians (82%), with a mean age of 62.5 years (range, 38-84 years) and mean body mass index of 29.2. One patient died owing to access-unrelated reasons, and one patient was lost to follow-up without AVF assessment after its creation. From the remaining 49, 3 patients had a follow-up of less than 4 weeks and were excluded from maturation, primary failure, and dialysis initiation analysis (because those factors could not be evaluated yet), leaving 46 patients in this evaluation. Maturation was achieved in 91% of patients. The primary failure rate was 9%. A primary patency rate of 77% was observed at 6, 12, and 18 months. The secondary patency rate was 91% at 6 months, and 85% at 12 months and 18 months. Both primary patency and secondary patency did not differ statistically when comparing forearm AVF with BCAVF (P > .25). Successful cannulation was achieved in 86% of patients (32/37) requiring dialysis with a median time from creation to cannulation of 46 days. Of those patients, the functional patency rate was 94%. Five patients underwent seven interventions to maintain or restore patency or functionality, with an overall rate of 0.248 interventions per patient-year.

CONCLUSIONS

AVFs created with VasQ external support device demonstrated promising patency and functionality outcomes in multicentric real-world setting across the two most commonly used anatomic locations.

A Comparison of Outcomes Between Open and Endovascular Arteriovenous Access Creation for Hemodialysis

OBJECTIVE

Preliminary outcomes for percutaneous endovascular autogenous access (endoAVF) have shown promising results; however, comparisons with surgical cohorts in dialysis populations are lacking. This study compares autogenous arteriovenous access created with the EverlinQ endoAVF system with accesses created by conventional surgical technique with respect to functional and patency related outcomes.

METHODS

This is a multicenter, retrospective review of autogenous arteriovenous accesses entered into a prospective database. Patients receiving radiocephalic, brachiocephalic, or endoAVF arteriovenous accesses between 2014 -2019 were included. Autogenous access maturation, primary patency, secondary patency, steal syndrome, and re-interventions were collected and analyzed using standard statistical and survival analyses.

RESULTS

A total of 369 accesses were created during the study period, including 61 endovascular accesses, 171 radiocephalic accesses, and 137 brachiocephalic accesses (median follow-up 17 months; range 1 - 71 months). Maturation failure at the end of follow-up was 27±6%, 27±5%, and 18±4% for endovascular, radiocephalic, and brachiocephalic accesses, respectively (p =.049 for brachiocephalic vs. endovascular accesses). Primary patencies at 12 and 24 months were 42±5% and 32±7% for endovascular accesses, 43±4% and 24±4% for radiocephalic accesses, and 42±4% and 29±4% for brachiocephalic accesses (p=.906). Secondary patencies at 12 and 24 months were 68±6% and 60±7% for endovascular accesses, 75±3% and 67±4% for radiocephalic accesses, and 91±3% and 81±4% for brachiocephalic accesses (p=.006 for brachiocephalic vs. endovascular accesses). There were no statistically significant differences in ischemic steal syndrome (3.3%, 4.1% and 8.0%; p=.229) or total reinterventions/year (1.0±3.1, 0.9±1.8, and 1.2±1.8; p=.289) for endovascular, radiocephalic, or brachiocephalic arteriovenous accesses, respectively.

CONCLUSIONS

EndoAVF compare favorably with respect to maturation and patency compared with surgically created accesses in a real-world cohort. Outcomes and reintervention rates are similar to conventional radiocephalic arteriovenous accesses, but are inferior with respect to patency and maturation to brachiocephalic accesses.

New Devices and Technologies for Hemodialysis Vascular Access: A Review

In the United States, hemodialysis remains the most common treatment modality for kidney failure, chosen by almost 90% of incident patients. A functioning vascular access is key to providing adequate hemodialysis therapy. Recently, major innovations in devices and technology for hemodialysis vascular access care have rapidly changed the landscape. Novel endovascular devices for creation of arteriovenous fistulas may offer a solution to the barriers encountered in initiating maintenance hemodialysis with a permanent vascular access rather than a central venous catheter (CVC). Furthermore, in the prevalent hemodialysis population, the minimally invasive endovascular arteriovenous fistula procedure should help improve long wait times for vascular access creation, which remains a major barrier to reducing CVC dependence. Bioengineered grafts are being developed and may offer another option to polytetrafluoroethylene grafts. Early studies with these biocompatible grafts are promising, as additional studies continue to evaluate their clinical outcomes in comparison to cryopreserved or synthetic options. Prolonging the vascular access patency with appropriate use of devices such as drug-coated balloons and stent grafts may complement the novel techniques of creating arteriovenous access. Finally, innovative solutions to treat stenosed and occluded thoracic central veins can provide an approach to creating a vascular access and allow patients with exhausted vasculature to remain on hemodialysis. The robust developments in hemodialysis vascular access are likely to change practice patterns in the near future.

Endovascular arteriovenous fistulas- are they the answer we haven't been looking for?

INTRODUCTION

Surgically created arteriovenous fistulas are the accepted gold standard for the establishment of hemodialysis access in patients requiring dialysis. However, primary and maturation failures may limit their usage. Recent advances in endovascular technology have resulted in the creation of devices for endovascular arteriovenous fistula formation. These devices may offer an additional or alternative approach to fistula formation in patients with end-stage kidney disease.

AREAS COVERED

This review describes the limitations of surgical arteriovenous fistulas and the endovascular devices currently available. The review covers initial trial data and subsequent studies examining their use.

EXPERT OPINION

Early results achieved with endovascular fistula formation are encouraging. Current limitations of this technology include anatomic suitability and a high rate of re-interventions required to establish maturity. Greater uptake of the technology will also require a review of long-term outcomes in larger patient cohorts.

Comparison of Ellipsys Percutaneous and Proximal Forearm Gracz-Type Surgical Arteriovenous Fistulas

RATIONALE & OBJECTIVE

Percutaneous arteriovenous fistulas (AVF) are created by establishing a proximal forearm anastomosis and offer a safe and reliable vascular access. This study compares the Ellipsys percutaneous AVF with a proximal forearm Gracz-type surgical AVF, chosen for comparison as it is constructed at the same anatomical site.

STUDY DESIGN

Retrospective study of prospectively collected clinical data.

SETTING & PARTICIPANTS

All vascular access procedures conducted during a 34-month period were reviewed. The study groups comprised 89 percutaneous AVFs and 69 surgical AVFs.

EXPOSURE

Percutaneous or surgical AVF placement.

OUTCOME

AVF patency, function, and complications.

ANALYTICAL APPROACH

Patency rates for each AVF group were evaluated by competing risk survival analysis using a cumulative incidence function. Association of primary, primary assisted, and secondary patency with the AVF groups was examined by Cox proportional hazard models.

RESULTS

Technical success was 100% for both groups. Average procedure times were 14 minutes for percutaneous AVFs and 74 minutes for surgical AVFs (P < 0.001). Proximal radial artery (PRA) was used in all percutaneous AVF cases. Inflow for surgical AVFs included radial (30%), ulnar (12%), and brachial (58%) arteries. Outflow veins for both groups were the cephalic and/or basilic veins. Access flow volumes, times to maturation, and overall numbers of interventions per patient-year were not significantly different. Cumulative incidence of primary patency failure at 12 months was lower for surgical AVF (47% vs 64%, P = 0.1), but secondary patency failure was not different between groups (20% vs 12%, P = 0.3). PRA surgical AVFs had similar primary patency (65% vs 64%, P = 0.8) but higher secondary patency failure rates than percutaneous AVFs at 12 months (34% vs 12%, P = 0.04).

LIMITATIONS

Retrospective study with a relatively short follow-up period, and not all patients required hemodialysis at the end of study.

CONCLUSIONS

Both percutaneous and surgical AVFs demonstrated high rates of technical success and secondary patency. Percutaneous AVFs required shorter procedure times. The rate of intervention was similar. When a distal radial artery AVF is not feasible, percutaneous AVF might offer an appropriate procedure for creating a safe and functional access, maintaining further proximal forearm surgical AVF creation options.

Comparison of surgical versus percutaneously created arteriovenous hemodialysis fistulas

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Initial Outcomes Following Introduction of Percutaneous Arteriovenous Fistula Program with Comparison to Historical Surgically Created Fistulas

BACKGROUND

Recently, there has been an abundance of encouraging data regarding the creation of percutaneous arteriovenous fistulas. Despite promising data regarding their clinical maturation, a paucity of data exists which provides direct comparison between percutaneously created AVFs (pAVF) and open surgically created AVFs (sAVF). This study has 2 primary objectives: First, to compare clinical outcomes of pAVFs to sAVFs, with emphasis on clinical maturation and frequency of postoperative interventions to facilitate maturation. Second, to contribute toward the evidence-based incorporation of the pAVF procedure into the hemodialysis access algorithm.

METHODS

A single-center retrospective review was performed on all consecutive patients undergoing surgically created brachiocephalic arteriovenous fistula (BC-AVF, sAVF group) from January 1, 2018 to December 31, 2018 and Ellipsys-created percutaneous arteriovenous fistula (pAVF group) from January 1, 2019 to December 31, 2019. Comparative analysis between groups was performed.

RESULTS

A total of 24 patients underwent Ellipsys-created pAVF with mean age of 56.7 ± 22.6 years (12 males [50%], 12 females [50%]) and 62 patients underwent surgically created BC-AVF with mean age of 62.5 ± 13.2 years (32 males [52%], 30 females [48%]). Both the pAVF and sAVF groups had comparable mean operating times (60 ± 40 vs. 56 ± 25 min, P = 0.67) and frequency of procedural technical success (23 [96%] vs. 62 [100%], P = 0.28), respectively. The pAVF group had a lower clinical maturation rate (12 [52%] vs. 54 [87%], P = 0.003) and a higher primary failure rate (9 [39%] vs. 6 [10%], P = 0.003) when compared to the sAVF group. The pAVF group had an increased overall rate of undergoing a postoperative intervention (18 [78%] vs. 13 [21%], P< 0.001), as well as an increased number of total postoperative interventions (1.1 ± 0.9 vs. 0.3 ± 0.6 interventions, P< 0.001) compared to the sAVF group. Percutaneous transluminal angioplasty of the juxta anastomotic segment was the most prevalent postoperative intervention performed in the pAVF group and occurred at a significantly increased frequency when compared to the sAVF group rate (13 [57%] vs. 5 [8%], P< 0.001).

CONCLUSIONS

In our single-center retrospective review, patients undergoing Ellipsys-created pAVF in the first year following introduction of percutaneous endovascular had inferior rates of clinical maturation and underwent more postoperative interventions when compared to historical patients undergoing surgically created BC-AVF. Outcome discrepancies compared to previously reported Ellipsys data demonstrate a need for further studies examining the practical translatability of the pAVF.

Initial experience with the Ellipsys Vascular Access System for percutaneous arteriovenous fistula creation in adolescents: A case report

This retrospective, single center, case report describes the first use of the Ellipsys Vascular Access System for percutaneous arteriovenous fistula (pAVF) creation in children. Two adolescent (<20 year of age) patients (18 and 19-year-old females), one of whom was developmentally delayed, were not considered candidates for traditional surgical arteriovenous fistula creation. pAVF creation was successful in both patients using the Ellipsys device and physiologic maturation of the fistula was achieved within 8 weeks of creation with subsequent 2 needle cannulation. No complications or adverse events were encountered. pAVF creation with the Ellipsys device can be safely performed in adolescents. Further studies will be needed to validate the expanded use of these devices in children.

Anatomic suitability for commercially available percutaneous arteriovenous fistula creation systems

OBJECTIVE

The Food and Drug Administration recently approved two percutaneous arteriovenous fistula creation systems: the Ellipsys vascular access (EL) system and WavelinQ EndoAVF (WQ) system. Although the initial clinical trials of each system have demonstrated a high success rate, little detail on anatomic suitability was provided. We sought to determine the real-world applicability of the EL and WQ systems by studying them in a single representative cohort.

METHODS

All patients receiving a first-time arteriovenous access consultation at a single Veterans Affairs institution underwent extensive vein mapping of the bilateral upper extremities. Anatomic suitability was assessed in accordance with the manufacturer's instructions for use (IFU), and clinical usability was determined using additional published anatomic guidelines. The suitability for radiocephalic fistula (RCF) creation was also assessed. To estimate how often these systems would be used in practice, a clinical algorithm was created, with a preference for RCF creation, followed by percutaneous arteriovenous fistula (pAVF) creation, surgical fistula creation at the elbow, and, finally, graft placement.

RESULTS

During the study period, 116 upper extremities were measured in 58 male patients. Per the IFU, the rate of extremity suitability was 93% and 52% for the WQ and EL systems, respectively (P < .0001). In the same population, 32% of the extremities had acceptable anatomy for RCF creation. The overall clinical usability of these systems using more recent published guidelines was 55% for the WQ system and 44% for the EL system (P = .09). The usability of both pAVF systems was most limited by the size of the deep perforating cubital vein. The proximity of the antecubital perforator vein and proximal radial artery additionally limited EL usability. Based on the clinical algorithm, initial access creation would have been RCF creation for 31% of the cohort, followed by the WQ (32%), the EL (23%), surgical fistula creation at the elbow (18%), and graft placement (17%).

CONCLUSIONS

Anatomic suitability was greater for WQ than for EL when considering only the IFU. Once the full requirements for pAVF creation were considered, we found no significant differences in usability between the two systems. Anatomic analysis showed that pAVF creation can constitute a substantial part of a hemodialysis access practice.

Challenges and novel therapies for vascular access in haemodialysis

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

The role of surgery for assisted maturation after endovascular and percutaneous arteriovenous fistula creation

Even in the best of circumstances, a significant number of patients will require adjunctive endovascular and/or surgical revision prior to achieving functional patency after endovascular or percutaneous AVF creation, at least within the United States. This rate appears to be higher after percutaneous AVF than after endovascular AVF, although because published reports of the former are mostly derived from American experience and those of the latter derived from experience outside the United States, it is unclear whether these differences are due to the technique itself or cultural and/or anatomic differences in dialysis access practices and patient populations. If arterial inflow is poor, this should be corrected first. When flow is adequate (perhaps 900 cc/min) but no single vein is cannulatable, a dominant suitable vein can be superficialized or transposed. If no suitable vein is dominant (most accurately assessed by using an intraoperative flowmeter), the best vein can be used, with or without occlusion of the other veins or reimplantation into the brachial artery. Finally, if the original anastomosis remains the sole supply to the cannulated vein, the original fistula has achieved assisted primary maturation (and assisted primary patency continues), while if a new arteriovenous anastomosis has been constructed, the original fistula has failed. We point out that for this reason as well as to best utilize the upper arm for later access, endovascular and percutaneous AVFs should be constructed and maintained within an atmosphere where both surgeons and non-surgeons work together on the overall access plan.

Initial 6-month quality review of a percutaneous endovascular arteriovenous fistula program

Background:

Percutaneous arteriovenous fistulas have recently proven successful alternatives to surgical arteriovenous fistulas with encouraging initial results. The Ellipsys Endovascular Arteriovenous Fistula System utilizing ultrasound and thermal energy has recently received approval for use in the United States. At the University of New Mexico, we developed an integrated service between Vascular Surgery, Interventional Radiology, and Interventional Nephrology for percutaneous arteriovenous fistulas utilizing Ellipsys.

Methods:

We performed a retrospective chart review of the initial 6 months (January 1st 2019 to July 1st 2019) of 18 percutaneous arteriovenous fistula placements to evaluate our initial technical success rate, the number of arteriovenous fistulas meeting maturation characteristics or use in dialysis, and to identify areas for quality improvement.

Results:

Initial technical success was achieved in 17 out of 18 arteriovenous fistulas (94.4%). Three patients did not report for any follow-up at the end of the initial 6 months. Of the remaining patients, 7 out of 15 were using their arteriovenous fistulas or meeting maturation characteristics at the end of the study (46.7%). Patient loss to follow-up/no-show (16.7%), patient not yet requiring hemodialysis (27.8%), and poor post-surgical maturation and/or need for additional maturation procedures (55.6%) were the predominate reasons for non-use. We identified improved coordination of care, early intervention, and outpatient dialysis center education as the primary areas of focus for quality improvement.

Conclusion:

Initial technical success rate of percutaneous arteriovenous fistulas placement was comparable to published studies. Early and aggressive secondary angiographic interventions of arteriovenous fistulas failing to meet cannulation requirements, improved coordination of post-operative care, and outpatient dialysis center education appear to be the primary targets for quality improvement.

Avoiding hemodialysis access-induced distal ischemia

Timely creation and maintenance of a safe and reliable vascular access is essential for hemodialysis patients with end-stage renal disease. Hemodialysis access-induced distal ischemia (HAIDI) is a recognized complication of arteriovenous fistulas and grafts that may result in serious or even devastating consequences. Avoiding such complications is clearly preferred over treatment of HAIDI once established. Proper recognition of patients at increased risk of HAIDI includes careful pre-operative evaluation of the patient's medical and surgical history along with physical examination and imaging to determine a plan for creating a functional permanent access while minimizing the risk of distal ischemia. Our aim is to review identifying characteristics of individuals at risk of HAIDI and provide recommendations regarding pre-operative assessment. Vascular access options and techniques are suggested for establishing a functional vascular access without distal ischemia for such patients.

Interventional Nephrology: Opportunities and Challenges

The nephrologist has a pivotal role as the leader of multidisciplinary teams to optimize vascular access care of the patient on dialysis and to promote multidisciplinary collaboration in research, training, and education. The continued success of interventional nephrology as an independent discipline depends on harnessing these efforts to advance knowledge and encourage innovation. A comprehensive curriculum that encompasses research from bench to bedside coupled with standardized clinical training protocols are fundamental to this expansion. As we find ourselves on the threshold of a much-awaited revolution in nephrology, there is great opportunity but also formidable challenges in the field - it is up to us to work together to realize the enormous potential of our discipline.

Creating percutaneous radiocephalic arteriovenous fistulas at the wrist

BACKGROUND

The first arteriovenous fistulas were created at the wrist more than 60 years ago. Basic surgical construction techniques remain unchanged with mobilization and repositioning of the vessels followed by a sutured anastomosis. We used the Ellipsys device to construct percutaneous radiocephalic-arteriovenous fistulas at the wrist and report the results.

METHODS

Data were reviewed retrospectively for all patients who had a percutaneous radiocephalic-arteriovenous fistula created during a 6-month period. Each individual underwent ultrasound vessel mapping in addition to physical examination. When a radiocephalic-arteriovenous fistula was feasible and a communicating vein ⩾ 2 mm in diameter was noted in the distal forearm along with a radial artery ⩾ 2 mm, a percutaneous radiocephalic-arteriovenous fistula was considered and reviewed with the patient.

RESULTS

Four individuals met the criteria to consider a percutaneous radiocephalic-arteriovenous fistula and all elected to have the procedure performed. Ages were 54-85 years. Three were diabetic and one was female. All percutaneous radiocephalic-arteriovenous fistulas were technically successful. Two individuals had not yet started dialysis therapy. Successful and repetitive cannulation for the two individuals with catheters was initiated at 4 and 8 weeks post procedure. The two pre-dialysis patients had physiologic arteriovenous fistula maturation (6 mm vein diameter and >500 mL/min flow) at 4 and 12 weeks. There were no procedural or late complications and none required intervention. Follow-up was 8-23 months (mean 16 months).

CONCLUSION

The success of these percutaneous radiocephalic-arteriovenous fistulas suggests that use of the Ellipsys device will be applicable at the wrist in selected patients where appropriate vessel sizes and configurations are found.

Percutaneous creation of proximal radio-radial arteriovenous hemodialysis fistula before secondary brachial vein elevation

Objective:

We evaluate the creation of a percutaneous proximal radial artery–radial vein arteriovenous fistula with Ellipsys® instead of the usual first-stage brachial artery fistula prior to a second-stage brachial vein elevation, in patients with inadequate cephalic and basilic veins.

Methods:

Single center study of eight patients (six males, mean = 54 years) who underwent a two-stage brachial vein elevation procedure between May 2017 and October 2019. Inclusion criteria were life expectancy > 6 months, patent brachial and proximal radial artery (>2 mm in diameter) absent/inadequate cephalic and basilic veins, existence of a brachial vein >3 mm in diameter, and in continuity with a proximal radial vein > 2 mm in diameter.

Results:

Technical success was 100%. Four patients required angioplasty of a juxta-anastomotic stenosis, accounting for a 6-month primary and secondary patency rates were 68% and 100%, respectively. Access flow averaged 982 mL/min (range 768–1586) at final follow-up evaluation. There were no significant adverse events related to the procedures. All fistulae were elevated at 4–12 (mean: 8) weeks post creation and were successfully cannulated with two needles after healing was completed (2–4 weeks after elevation). No patients developed hand ischemia or arm edema.

Conclusions:

Percutaneous creation of a proximal radial artery–radial vein fistula followed by brachial vein elevation is a safe and reliable option for autogenous access creation in patients with inadequate cephalic or basilic veins. Minimally invasive radial artery inflow and longer available length of the targeted brachial vein available for elevation are the main advantages in skilled hands.

Endovascular versus surgical creation of arteriovenous fistula in hemodialysis patients: Cost-effectiveness and budget impact analyses

Objectives:

The aim of the present study was to perform cost-effectiveness and budget impact analyses comparing endovascular arteriovenous fistula creation to surgical arteriovenous fistula creation in hemodialysis patients from the National Healthcare Service (NHS) perspective in Italy.

Methods:

A systematic literature review has been conducted to retrieve complications’ rates after arteriovenous fistula creation procedures. One study comparing endovascular arteriovenous fistula creation, performed with WavelinQ device, to the surgical approach through propensity score matching was preferred to single-arm investigations to execute the economic evaluations. This study was chosen to populate a Markov model to project, on a time horizon of 1 year, quality adjusted life years and costs associated with endovascular arteriovenous fistula (WavelinQ) and surgical arteriovenous fistula options for both cohorts of incident and prevalent hemodialysis patients.

Results:

For both incident and prevalent hemodialysis patients, endovascular arteriovenous fistula creation, performed with WavelinQ, was the dominant strategy over surgical arteriovenous fistula approach, showing less cost and better patients’ quality of life. Compared to the current scenario, progressively increasing utilization rates of WavelinQ over surgical arteriovenous fistula creation in the next 5 years in incident hemodialysis patients are expected to save globally 30–36 million euros to the NHS.

Conclusion:

Endovascular arteriovenous fistula creation performed with WavelinQ could be a cost-saving strategy in comparison with the surgical approach for patients in hemodialysis. Future studies comparing different devices for endovascular arteriovenous fistula creation versus the surgical option would be needed to confirm or reject the validity of this preliminary evaluation. In the meantime, decision-makers can use these results to take decisions on the diffusion of endovascular procedures in Italy.

The Nephrologist as an Ultrasonographer

Ultrasonography is increasingly being used in the practice of nephrology, whether it is for diagnosis or management of acute or chronic kidney dysfunction, until progression to end-stage kidney disease, including preoperative assessment, access placement, and diagnosis and management of dysfunctional hemodialysis access. Point-of-care ultrasounds are also being used by nephrologists to help manage volume status, especially in patients admitted to the intensive care units, and more recently, for guiding fluid removal in the outpatient dialysis units. Fundamental knowledge of sonography has become invaluable to the nephrologist, and performance and interpretation of ultrasound has now become an essential tool for practicing nephrologists to provide patient-centered care, maximize efficiency, and minimize fragmentation of care. This review will address the growing role of ultrasonography in the management of a patient with CKD from the point of initial contact with the nephrologist throughout the spectrum of kidney disease and its consequences.

Recent Advances in Arteriovenous Access Creation for Hemodialysis: New Horizons in Dialysis Vascular Access

Recent advances in technology show promise in providing greater vascular access options for hemodialysis patients. This review discusses novel methods for creating an anastomosis for arteriovenous (AV) fistulas and new materials for prosthetic AV grafts. Two technologies for endovascular arteriovenous fistula creation, the Ellipsys and WavelinQ endovascular systems, are discussed. When an AV fistula is not possible, an AV graft or devices to augment the AV fistula may be appropriate. New materials that have been developed that show promise as an alternative to the expanded polytetrafluoroethylene graft are discussed. Such potential conduits include bioengineered vessels and both allogenic or xenogenic biologic grafts. Devices designed to optimize blood flow to reduce maturation failure and improve AV fistula outcomes are explored.