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

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.

Two-year cumulative patency of endovascular arteriovenous fistula

BACKGROUND AND OBJECTIVES

The recent advent of a device to create a proximal radial artery arteriovenous fistula using an endovascular approach to create the anastomosis represents a significant advance in dialysis access creation. This endovascular arteriovenous fistula offers the beneficial attributes of the proximal radial artery arteriovenous fistula while adding the advantages of avoiding a surgical procedure. The endovascular arteriovenous fistula can be created safely, functions well, has excellent patency, and has a high degree of patient satisfaction. The purpose of this study is to report the 2-year cumulative patency rate for a large multicenter cohort of endovascular arteriovenous fistula cases.

DESIGN

An endovascular arteriovenous fistula was created in 105 patients using either local or regional anesthesia and conscious sedation. Patient data were obtained from each program's electronic health record system. Data collection was truncated at 2 years postprocedure and used to calculate cumulative patency. Post-access creation patient satisfaction was assessed.

RESULTS

A physiologically mature arteriovenous fistula (blood flow ⩾500 mL/min and a target vein internal diameter ⩾4 mm) was obtained in 98%. A clinically functional arteriovenous fistula (supporting two-needle dialysis according to the patient's dialysis prescription) was demonstrated in 95%. Access failure resulting in the loss of access occurred in eight cases during the study period. The cumulative patency rate at 6, 12, 18, and 24 months was 97.1%, 93.9%, 93.9%, and 92.7%, respectively. The post-procedure patient evaluation emphasized a high level of patient satisfaction.

CONCLUSION

The proximal radial artery arteriovenous fistula created using an endovascular approach for the anastomosis is associated with excellent 2-year cumulative patency and is associated with a high level of patient satisfaction.

Feasibility for arteriovenous fistula creation with Ellipsys®

OBJECTIVE

To investigate the feasibility of percutaneous arteriovenous fistula creation in consecutive patients screened for first access creation.

METHODS

Prospective study of ultrasound mapping based on the following minimal anatomic requirements: a patent proximal radial artery and adjacent elbow perforating vein with straight trajectory, each greater than or equal to 2 mm in diameter and within 1.5 mm of each other. In addition, the same population was evaluated for feasibility of a distal radiocephalic fistula established.

RESULTS

One hundred consecutive patients were examined between November 2018 and January 2019. Sixty-seven were male (67%) and mean age was 61 years. Sixty-three patients (63%) and a total of 100 limbs (50%) were found to be eligible for a percutaneous fistula creation with Ellipsys^®. Thirty-seven percent of patients were ineligible because of the absence of both median cephalic and median cubital veins (15%), absence or inadequate elbow perforating vein and/or smaller than 2 mm proximal radial artery (14%), and/or distance greater than 1.5 mm (8%). We found suitable vessels for a surgical distal fistula creation in 91 extremities (45%), but this percentage dropped to 17% in patients over 70 years old. Among the 100 limbs eligible for percutaneous arteriovenous fistula, only 30 (30%) were eligible for radiocephalic arteriovenous fistula.

CONCLUSION

More than 60% of patients were eligible for Ellipsys. The absence of veins at the elbow and a large distance between vessels were the most common limiting factors. Less than one half of the patients were candidates for surgical fistula and this percentage dropped significantly for older individuals.

WavelinQ created arteriovenous fistulas versus surgical radiocephalic arteriovenous fistulas? A single-centre observational study

Purpose:

Devices to permit percutaneous endovascular arteriovenous fistula formation have recently been introduced into clinical practice with promising initial evidence. As guidelines support a distal fistula first policy, the question of whether an endovascular arteriovenous fistula should be performed as an initial option is introduced. The aims of this study were to compare a matched cohort of endovascular arteriovenous fistula with surgical radiocephalic arteriovenous fistulas.

Materials and methods:

Using data from a prospectively collected database over a 3-year period, a matched comparative analysis was performed.

Results:

WavelinQ arteriovenous fistulas (group W, n = 30) were compared with radiocephalic arteriovenous fistulas (group RC; n = 40). Procedural success was high with 96.7% for group W and 92.6% for group RC. Primary patency at 6 and 12 months was greater in group W (65.5% 6mo and 56.5% 12mo) compared to group RC (53.4% 6mo and 44% 12mo) ( p = 0.69 and 0.63). Mean primary patency was significantly lower for RC (235 ± 210 days) vs W (362 ± 240 days) ( p < 0.05). Secondary patency for group W was 75.8% and 69.5% at 6 and 12 months, respectively. Secondary patency for RC was lower at 66.7% and 57.6% at 6 and 12 months, respectively.

Conclusion:

Outcomes of WavelinQ arteriovenous fistulas in this series are similar to published results. When compared to a contemporaneously created group of surgical fistulas, WavelinQ demonstrated superior outcomes. These data would support that WavelinQ endovascular arteriovenous fistulas may be considered as a first option in the access pathway particularly if vessels at the wrist are absent or less than ideal.

Early cannulation of percutaneously created arteriovenous hemodialysis fistulae

INTRODUCTION

The optimal vascular access for most dialysis patients is an arteriovenous fistula and the recognized appropriate process of care for the chronic kidney disease patient is to have the access in place ready for use when renal replacement therapy is required. Unfortunately, as a result of multiple barriers, most patients start dialysis with a catheter and many experience multiple interventions. The recent advent of the percutaneous arteriovenous fistula may offer at least a partial solution to these problems. The purpose of this study was to report of the results of early cannulation of the percutaneous arteriovenous fistula.

MATERIALS AND METHODS

Early cannulation, less than 14 days post creation, was performed in 14 cases in order to avoid an initial catheter or continued use of a problematic catheter for dialysis. Immediately post access creation, blood flow ranged from 491 to 1169 mL/min (mean = 790 mL/min). Ultrasound was used to map potential cannulation sites prior to use. Cannulation was performed using plastic fistula cannulas.

RESULTS

Early cannulation was successful in this cohort of cases except for one cannulation complication. Dialysis treatments were otherwise uncomplicated. Primary patency at 3, 6, and 12 months was 76%, 76%, and 66%, respectively. Assisted primary patency for the same intervals was 100%, 100%, and 91%, respectively. Cumulative patency was 100% at all three-time intervals.

CONCLUSION

The results of this study suggest that the possibility of successful early cannulation with a percutaneous arteriovenous fistula can be considered as an additional factor in making this access a reasonable alternative for a surgically created arteriovenous fistula in appropriate patients.

Early cannulation of percutaneously created arteriovenous hemodialysis fistulae

INTRODUCTION

The optimal vascular access for most dialysis patients is an arteriovenous fistula and the recognized appropriate process of care for the chronic kidney disease patient is to have the access in place ready for use when renal replacement therapy is required. Unfortunately, as a result of multiple barriers, most patients start dialysis with a catheter and many experience multiple interventions. The recent advent of the percutaneous arteriovenous fistula may offer at least a partial solution to these problems. The purpose of this study was to report of the results of early cannulation of the percutaneous arteriovenous fistula.

MATERIALS AND METHODS

Early cannulation, less than 14 days post creation, was performed in 14 cases in order to avoid an initial catheter or continued use of a problematic catheter for dialysis. Immediately post access creation, blood flow ranged from 491 to 1169 mL/min (mean = 790 mL/min). Ultrasound was used to map potential cannulation sites prior to use. Cannulation was performed using plastic fistula cannulas.

RESULTS

Early cannulation was successful in this cohort of cases except for one cannulation complication. Dialysis treatments were otherwise uncomplicated. Primary patency at 3, 6, and 12 months was 76%, 76%, and 66%, respectively. Assisted primary patency for the same intervals was 100%, 100%, and 91%, respectively. Cumulative patency was 100% at all three-time intervals.

CONCLUSION

The results of this study suggest that the possibility of successful early cannulation with a percutaneous arteriovenous fistula can be considered as an additional factor in making this access a reasonable alternative for a surgically created arteriovenous fistula in appropriate patients.

Early experience and observations in endovascular dialysis fistula re-intervention

In recent years, new emerging technology has allowed the endovascular creation of dialysis fistulas in the proximal forearm without the need for open surgery. Two such systems currently exist, and evidence to date has demonstrated high rates of technical success in fistula creation, high rates of dialysis functionality, and low rates of re-intervention using both systems. Whilst early trial data has demonstrated lower rates of re-intervention to maintain patency compared to surgical fistulas, endovascular re-interventions are still required to maintain functionality. The endovascular fistula (endoAVF) typically exhibits a shared drainage pattern and is morphologically distinct from the surgical fistula and patterns of failure observed often differ to what has been traditionally encountered. A fresh approach and understanding is therefore required and here we share our observations and experience of endovascular re-intervention in endoAVF created with the Wavelinq system.

Patient selection, education, and cannulation of percutaneous arteriovenous fistulae: An ASDIN White Paper

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

Preoperative assessment for percutaneous and open surgical arteriovenous fistula creation in patients for haemodialysis

Preoperative assessment prior to surgical arteriovenous fistulas (AVFs) including ultrasound-guided mapping has been shown to have beneficial effects on their immediate success as well as early outcomes. This has led to their wide acceptance and adoption however clinical practice criteria is variable and is reflected in variabilities in practice. When transposing this to percutaneously created endovascular AVFs (endoAVFs), variable preoperative assessment criteria could equally result in variable practice and potentially subsequent and expectant outcomes. We aimed to review literature on reported validated methodologies and workflows of preoperative assessment for surgical AVF creation as reported in highest levels of available evidence, specifically randomized controlled trials. Published practice recommendations and guidelines on best clinical practice as well as systematic reviews and meta-analyses of published studies were also reviewed. Data on practice methodology from identified trial publications and protocols was collated and a summative narrative synthesis was carried out which compared these methodologies to additional assessments that may be required when targeting assessment for percutaneous endoAVF formation, based on our units experience as part of an international multicentre trial. In this review we present a brief overview of published literature and guidelines and propose a unified and uniform workflow for preoperative assessment for surgical AVFs and endoAVFs to aide clinical and imaging practice.

A systematic review, meta-analysis, and meta-regression of the efficacy and safety of endovascular arteriovenous fistula creation

OBJECTIVE

The percutaneous endovascular approach to arteriovenous fistula (AVF) creation is a minimally invasive alternative to surgical AVF creation. This systematic review and meta-analysis aimed to investigate the efficacy and safety of endovascular AVF creation in patients with end-stage renal disease.

METHODS

This study conformed to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. An electronic search was performed on major databases to identify relevant articles. Meta-analysis of proportions and meta-regression were conducted.

RESULTS

Seven studies totaling 300 patients were included, of which four evaluated the everlinQ (TVA Medical, Austin, Tex) and three employed the Ellipsys (Avenu Medical, San Juan Capistrano, Calif) systems. The overall technical success rate was 97.50% (95% confidence interval [CI], 94.98-99.31%; I² = 0.00%; P = .487). The 90-day maturation rate was 89.27% (95% CI, 84.00-93.66%; I² = 21.29%; P = .283), and the 6-month patency and 12-month patency were 91.99% (95% CI, 87.98-95.35%; I² = 0.00%; P = .780) and 85.71% (95% CI, 79.90-90.71%; I² = 0.00%; P = NS), respectively. The overall procedure-related complication rate was 5.46% (95% CI, 0.310-14.42%; I² = 81.21%; P = .000). Meta-regression was conducted on the pooled rates of technical success and complication, showing that age, diabetes, white race, hypertension, on dialysis, and body mass index were not significant sources of heterogeneity.

CONCLUSIONS

Current endovascular AVF systems appear to be effective and safe. However, given the lack of head-to-head comparative analyses with surgical AVF creation, superiority cannot be established.

Ultrasound in dialysis access: Opportunities and challenges

Sonography is increasingly being used by nephrologists and the field of dialysis access is no exception. Advances in technology have allowed the addition of this universally available, portable, non-invasive tool to the nephrologist's armamentarium, which provides information on both morphology and physiology without the need for contrast or radiation. Ultrasound may be used across the spectrum of dialysis access, including central venous catheter placements, vascular mapping, regional anesthesia, creation, maintenance and assessment of hemodialysis access as well as assessment of the abdominal wall and peritoneal dialysis catheter placements. However, the lack of exposure in most training programs limits incorporation of routine use of ultrasounds in nephrology practice. As our specialty embarks on the ultrasound revolution, a two-pronged approach is essential to provide ample training opportunities while ensuring establishment of basic standards for training and competency.

Vascular access for hemodialysis: A perpetual challenge

Vascular access for hemodialysis has a long and rich history. This article highlights major innovations and milestones in the history of angioaccess for hemodialysis. Advances in achievement of lasting hemodialysis access, swift access transition, immediate and sustaining access to vascular space built the momentum at different turning points of access history and shaped the current practice of vascular access strategy. In the present era, absent of large-scale clinical trials to validate practice, the ever-changing demographic and comorbidity makeup of the dialysis population pushes against stereotypical angioaccess goals. The future of hemodialysis vascular access would benefit from proper randomized clinical trials and acclimatization to clinical contexts.

Percutaneous arteriovenous fistulae: Technique, feasibility and results

Patients with end-stage renal disease that require chronic haemodialysis need a reliable vascular access. Unanimously, native arteriovenous fistulae are considered to be the most reliable access for patients with reasonable life expectancy. For the last 60 years arteriovenous fistulae have been created surgically at the wrist or the elbow with variable rates of success, maturation problems, reinterventions and complications, making this field of surgery particularly challenging and full of scientific controversies. The recent addition of the technical ability to create arteriovenous fistulae percutaneously comes to add one more option for the patients and one more source of controversy for the experts.

Clinical hemodialysis experience with percutaneous arteriovenous fistulas created using the Ellipsys® vascular access system

INTRODUCTION

The aim of this study is to report our clinical hemodialysis experience using a percutaneous arteriovenous fistula (pAVF) created with the Ellipsys® vascular access system. This pAVF device creates a permanent AVF anastomosis between the proximal radial artery (PRA) and the deep communicating vein (DCV) in the proximal forearm.

METHODS

The medical records of all patients with a pAVF were retrospectively reviewed. The clinical data analyzed included reliability of pAVF use, quality of dialysis, rate and success of puncture, and pAVF related complications, along with incidence of subsequent interventions.

FINDINGS

Between May 2017 and November 2018, 34 patients had a pAVF created with technical success in 33 patients (97%). Twenty-eight out of 34 (82%) patients had successful two-needle cannulation within 10 days to 6 weeks after pAVF creation. The mean Kt/v was 1.6 (1.2-2) and the average recirculation was 10%. Fifteen patients (44%) needed no further access intervention. Twelve patients (35%) required an additional procedure to assist maturation of the pAVF in order to facilitate puncture. The average blood flow measured at the brachial artery, before the first cannulation, was 850 ml/min. From causes unrelated to the procedure, four patients died during the follow-up study. Two patients required revision to a surgical AVF. None of the pAVFs developed aneurysmal degeneration steal syndrome, or high access flow related issues.

DISCUSSION

The Ellipsys® pAVF offers a safe and functional vascular access for hemodialysis. Advantages included prompt access maturation, avoidance of high flow AVFs, and a simple nonsurgical procedure with high patient satisfaction. Functional outcomes are equivalent and likely better than surgical fistulas. There appears to be less aneurysmal degeneration and need for future re-intervention. Objective dialysis parameters indicate excellent quality of hemodialysis for the patient.

Future of IR: Emerging Techniques, Looking to the Future…and Learning from the Past

Innovation has been the cornerstone of interventional radiology since the early years of the founders, with a multitude of new therapeutic approaches developed over the last 50 years. What is the future holding for us? This article presents an overview of the in-coming developments that are catching on at this moment, particularly focusing on three items: the new applications of existing techniques, particularly embolotherapy and interventional oncology; the cutting-edge devices; the imaging technologies at the forefront of the image-guidance. Besides this, clinical vision and patient relation remain crucial for the future of the discipline.

A survival guide for endovascular declotting in dialysis access: procedures, devices, and a statistical analysis of 3,000 cases

INTRODUCTION

Thrombosis is the most important access-related complication. Several declotting procedures have been suggested falling mainly into two categories; thrombolysis-dependent and thrombectomy-dependent.

AREAS COVERED

Seventeen studies after 2001 have been published on percutaneous treatment of thrombosed vascular access. Authors performed a systematic review of these studies together with a parametric meta-analysis of data available investigating clinical success, postintervention assisted primary patency (PAPP) and independent factors that could influence outcome measures.

EXPERT COMMENTARY

A shift to thrombectomy-dependent procedures is observed with a view to diminishing complications from the use of thrombolytic agents. Arteriovenous fistulas provide significantly better PAPP, while newer studies show improved, non-significant results compared with older ones. The role of improvement of devices for subsequent angioplasty is of equal importance, if not more, for improved declotting results.