Renal Interventions 8

In this issue:

4–6

“EndoAVF 2.0” projects evaluated in CX debate

The advent of endovascular arteriovenous fistula (endoAVF) creation with the development of the Ellipsys (Medtronic) and WavelinQ (BD) systems marks a “major innovation in dialysis access”— and a “mounting evidence base” demonstrates their high functional patency rates. So said interventional radiology lead at East and North Herts NHS Trust (Stevenage, UK) Kate Steiner, who led a discussion of the next generation of endoAVF devices at the Charing Cross Symposium 2023 (25–27 April, London, UK). Joining her was Robert Shahverdyan (Asklepios Clinic Barmbek, Hamburg, Germany) and Simon Hogan (Pathfinder Medical, London, UK), who offered a preview of the future of the technology.

HOGAN OPENED PROCEEDINGS with a dive into the ePath system currently in development at Pathfinder Medical, which he explained has its roots in the work of the company’s electrical engineer CEO Sorin Popa at Imperial College London. He explained that it is a twin-catheter system with a 3Fr target that goes into the target artery, and a 5Fr crossing catheter for the target vein.

Under fluoroscopic guidance, the ePath system sees the two catheters inserted “either from a parallel point of view or anti-parallel way depending on the access sites that are being used”. The target device has a basket on the end that acts as a sensor, while there are four electrodes printed into the surface of the crossing device,” Hogan outlined. These electrodes generate electrical fields in which the alignment of the target basket can be detected.

“You know exactly where the needle is pointing when you rotate the handle. The display is very intuitive—it is just two arrows that point to each other, and when it turns green you know the devices are aligned. Then, the needle pops out straight into the middle of the basket. You deploy a guide wire, after which you can deploy a stent or balloon over the top of that: whatever the operator desires to create the fistula.”

Hogan added that preclinical trials in cadaveric and animal models had tested the system in the wrist and other sites in the forearm. “We hope to be able to advance our clinical research in the coming months,” he said.

Continued on page 13

New UKKA guideline places patient choice at

The recent haemodialysis access guideline update from the UK Kidney Association (UKKA) comes in the run-up to the 2023 UK Kidney Week conference (UKKW; 5–7 June, Newport, UK), and marks a considerable shift in how the organisation recommends that clinicians approach choices in vascular access for patients. Two of the UKKA update’s authors, Damien Ashby (Hammersmith Hospital, London, UK) and Catherine Fielding (University Hospitals of Derby and Burton NHS Foundation Trust, Derby, UK) spoke to Renal Interventions to detail how that shift was built on a desire to better consider the patient voice in all aspects of access care.

Asked what distinguishes this version of the UKKA guideline, Fielding began by highlighting the multidisciplinary involvement in the writing of the update. The text of the guideline states that nephrologists, surgeons and radiologists were all involved—as well as nurses like herself.

optimum form of access and provide a percentage of patients that should receive one. “It is not consistent with making the patient voice and patient choices the centre of care that hospitals should need to reach targets for types of access,” he argued. “We are moving away from that by recognising patient characteristics and what is sometimes the uncertainty of the evidence base.”

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Explaining the reasoning behind this, Fielding said: “It sometimes feels like it is not those who perform procedures like cannulation who are writing the guidelines on them. I am not saying that they should not have their own perspectives, but it leads you to wonder how some guideline proposals can be put into clinical practice. I think that practical, pragmatic element comes strongly through in this guideline—so that it is not just doctors but other professions that can implement it.”

Not only were a variety of specialties included, but there were also “three very active patient representatives” at the heart of the process. Developing this point, Ashby added: “The big thing that moves the needle with this guideline is how we constantly tried to involve the patient voice. The guideline emphasises different patient characteristics rather than just saying: ‘This is the best access for you.’”

Asked what might surprise some readers about the update, Ashby said that, though it would not surprise patients or nurses, it may be unexpected for some clinicians that the update does away with the concept of targets. Other guidelines, he suggested, prescribe fistulas as the

The patient voice is the fundamental difference in this guideline compared to both those issued by the UKKA in the past and those seen elsewhere, Ashby and Fielding agreed. Fielding also noted that the writing team contended with a “mushrooming” breadth of research in vascular access, which meant they were required to judge carefully what now warranted recommendation, and what still called for more research. In particular, however, they looked at qualitative data, something which they suggest may not have been included to the same degree in previous guidelines. “Once you start looking at studies of patient perspectives, it changes your own,” Ashby said.

The consideration of the patient perspective meant making the guideline more readable, too. Comparing the UKKA guideline with the Kidney Disease Outcomes Quality Initiative (KDOQI) guideline on vascular access, Ashby made the case that the references “running into the thou-

Continued on page 2

“The guideline emphasises diff erent patient characteristics rather than just saying: ‘This is the best access for you.'”

Damien Ashby

the heart of vascular access care

Wei Li and Mareena Zachariah on IN training pages 14

UK Kidney Week preview pages 12

CX Symposium summarised pages

Profile: Daniel Patel page 10

New UKKA guideline places patient choice at the heart of vascular access care

Continued from page 1

sands” in the latter make it a comprehensive and impressive document, but one that is more of a challenge for readers. Part of the UKKA guideline team’s motivation was to provide information in a clear manner even to patients and carers, facilitating more informed decision-making.

On the content of the update itself, Ashby and Fielding concurred on a range of issues it addresses. “Timely treatment” of thrombosis, it suggests, is most effective—and it makes fistulas in particular more likely to work. Ashby highlighted that this is “an example of something where a better access outcome is also better for a patient’s experience […] which might even be a better reason to do it”.

The guideline has added a dedicated section on central venous stenosis (CVS) because, Ashby averred, “it is an important but maybe hidden problem that we wanted to highlight in the correct way”. Ashby advised, however, that the CVS recommendations are “not easy to summarise due to a complex and diverse literature”, and that the section demands more detailed reading.

those decisions is very difficult”. However, she explained that the move towards shared decision-making is connected to a drive towards better informing patients, too. It is also about asking not only what is the best access from a clinician’s point of view, but taking a broader look at a patient’s life—and what kind of life they want to have after they receive their access.

follow-up time to improve AVF outcomes, study authors propose

Key recommendations:

“The other thing we have really highlighted through the guideline—and this is something both Damien and I are passionate about—is how important it is that the information we give patients is accurate and that we have interpreted the research accurately,” Fielding said. She further emphasised that it is vital that patients are informed of gaps in research, stating that “we should not be afraid” to tell patients when the literature is “ambiguous”. She also said that it is important to remember the “actual consequences to having a vascular access”, particularly on patients’ “day-to-day life”, referencing not only infection risk but also the “adverse effects of using it for haemodialysis”, such as cannulation pain.

An association has been found between early follow-up evaluation in the wake of arteriovenous fistula (AVF) creation procedures and reduced time to successful cannulation for dialysis by the authors of a report in the Annals of Vascular Surgery.

FIRST AUTHOR MARIAH BUZZELL AND corresponding author Yana Etkin (both Zucker School of Medicine at Hofstra/Northwell, Hempstead, USA) et al carried out a retrospective analysis of patients at a single centre to examine the effects of follow-up timing on cannulation outcomes. With reference to studies including Jehad Almasri (Mayo Clinic, Rochester, USA) et al’s in the Journal of Vascular Surgery in 2015, they state that AVF maturation takes 3–4 months with a 25–50% rate of secondary maturation and 20–60% overall failure rate.

Ashby and Fielding concurred elsewhere also that an endovascular approach to many types of access dysfunction is “at least as good” as a surgical one. On new technologies such as drugcoated balloons, there was not sufficient existing evidence to make definitive recommendations, they said.

Queried on the potential consequences of giving patients an increased role in clinical decisions, Fielding stated that “actually putting all of the responsibility on the patient to make

Ashby concurred, saying: “It is not like giving someone a menu in a different language then asking what they want for dinner. You have got to help people to work out what those choices are and what they mean.” He drew a comparison with oncology, where he argued that cancer patients are often presented with a range of treatments, and he suggested that kidney disease patients should be offered similar “genuine choices” that reflect their needs and preferences. He referred to William Osler, who stated: “The good physician treats the disease; the great physician treats the patient who has the disease.”

Their concluding assessment of the guideline was that it “honestly summarises” the research in the field, “acknowledging uncertainties”. Most of all, they stressed its focus on the patient, while Fielding said that the full text of the guideline provides “very detailed rationales” for its suggestions. Both paid tribute to one of the patient representatives on the writing team who passed away during the writing process, which Ashby said served as a “big reminder” of the reality behind the recommendations. “For these people, it is their lives and their lifestyle. There is no way you can be doing this without remembering that this is all about a patient and their experience.”

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They note also that the Kidney Disease Outcomes Quality Initiative (KDOQI) guideline recommends a follow-up evaluation at 4–6 weeks for those who receive an AVF. “This recommendation,” they emphasise however, “is based only on expert opinion and [is] ‘ungraded’ due to lack of strong evidence, as few studies have assessed the follow-up schedule.”

Seeking to contribute to the body of evidence, they devised their single-centre retrospective analysis to include 517 patients with AVFs created by one board-certified surgeon between 2017 and 2021. In total, after loss to follow-up, the data from 400 patients were used, with 289 in an early follow-up group, where the median time to follow-up was 39 days, and 111 in a delayed follow-up group, where the median time was 78 days.

The authors found a maturation rate of 81% in the early group and 87% in the delayed group (p=0.1), and both groups experienced similar rates of reintervention for maturation assistance (57% versus 66%; p=0.2). Regarding time to first cannulation, however, there was significant difference. The early group had a “significantly shorter median time to cannulation” of 50 days compared with the delayed group’s 88 (p<0.0001). The patients in this group also experienced a shorter median time to catheter-free haemodialysis of 75 days to 118 (p<0.0001). Four months after their AVF creation procedures, 74% of those in the early follow-up group had successfully undergone cannulation compared to 63% in the delayed follow-up group (p=0.0001). At the same point, the incidence of catheter-free dialysis was 65% in the early follow-up group and 50% in the delayed follow-up group (p=0.036).

Reviewing their findings, the study authors cite advantages of successful AVFs compared with central venous catheters (CVCs), among them better long-term patency and lower infection rates. Cited as a drawback, AVFs’ long maturation periods may be mitigated, Buzzell et al suggest, by earlier follow-up. “Instituting a standardised post-operative follow-up schedule after AVF creation could be a low-cost intervention for improving access-related outcomes,” they propose, adding finally that it may also succeed in cutting the time spent by patients using CVCs.

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Catherine Fielding

Damien Ashby

Cut

“I think that practical, pragmatic element comes strongly through in this guideline—so that it is not just doctors but other professions that can implement it.”

Catherine Fielding

Patient choice on treatment is vital—the effect of a treatment on quality of life an essential consideration

“Timely” thrombosis treatment leads to better outcomes for fistulas— and better experiences for patients

Endovascular treatment of access dysfunction as good as surgical

IN.PACT AV three-year subanalysis trial data show “durable” long-term results

The vascular access masterclass session at Charing Cross (CX) Symposium 2023 (25–27 April, London, UK) saw a first-to-podium presentation by Andrew Holden (Auckland City Hospital, Auckland, New Zealand) in which he presented new data from the IN.PACT AV Access trial of the IN.PACT AV (Medtronic) drug-coated balloon (DCB). Offering three-year subanalysis data, he said that the study is “the only randomised pivotal trial of a device treating dysfunctional arteriovenous fistulas (AVFs) to demonstrate consistent and sustained clinical benefit” up to three years.

Establishing some background to the study, Holden noted that there have been eight published peer-reviewed studies with outcomes reported through to three years, but he said that all of these were single-centre with no adjudication—and that “all except one were single-arm and retrospective”. That means there is, in his words, “a paucity of evidence of long-term outcomes after treatment of stenoses in AV access”.

The IN.PACT AV study was initially planned to extend to 24 months, and a five-year extension meant a shrinking of the pool of participants as a result of death, withdrawal and declined consent

to further study. In total, 133 participants completed their three-year visit out of an original cohort of 330 patients receiving the index procedure. Of that 330, 170 were in the IN.PACT AV arm, while 160 received percutaneous transluminal angioplasty (PTA). In the IN.PACT AV arm, the mean age was 65.8 years and 112 of 170 were male. The standard PTA arm had a mean age of 65.5 and 101/160 were male.

As presented last year at CX, at 36 months, the DCB arm yielded a target lesion primary patency (TLPP) rate of 43.1% while the PTA arm had a rate of 28.6%, a statistically significant patency advantage for the DCB. This year, Holden set out for the first time the results of subgroup analyses in patients receiving an AVF in the forearm and upper arm at three years.

Those analyses included one in which the results were stratified by AVF type. In that analysis, the IN.PACT AV arm had a patency rate of 44.5% in forearm (radiocephalic) AVFs and 39.9% in upper arm (brachiocephalic and brachiobasilic) AVFs at 36 months, while the same rates with PTA were 33.8% and 21.3%, respectively. The patency advantage for DCB was significant for both forearm and upper arm fistulas.

The authors also stratified results by lesion type, with a DCB rate of TLPP of 50.6% at 36 months for de novo lesions and 40.5% for restenotic lesions. This was

First-in-human study update indicates “excellent” patency results with restorative dialysis graft

In a first-to-podium presentation during the vascular access masterclass, Frans Moll (University Medical Center Utrecht, Utrecht, Netherlands) provided the audience with an update on the novel Axess graft (Xeltis), which is intended to improve haemodialysis access outcomes via endogenous tissue restoration (ETR).

“THIS GRAFT CAN BRING A BRIGHTER future for the increasing number of patients who depend on dialysis treatments,” Moll told Renal Interventions. “And, I think we could see this in the next two-to-three years—the study is running, patients are actively being enrolled, and we are seeing very positive outcomes. We always have to be modest, but we are certainly optimistic about this.”

Moll highlighted the goal of the device: to provide an implantable polymer-based technology that harnesses the body’s natural ability to regenerate cells. The Axess graft utilises supramolecular chemistry and precise electrospin-

ning, offering the basis for a tuneable medical device that can act as a scaffold and allow the body to effectively create its own vessel.

Following implantation, ETR enables the graft to gradually be absorbed by the body, resulting in a ‘natural, living’ graft akin to an autologous arteriovenous fistula (AVF). Moll also noted that the proprietary technology behind Axess can be ‘coded’ during the manufacturing process, enabling absorption times to be adjusted.

The goal, Moll said, is to combine the early-stage benefits of an arteriovenous graft (AVG), including the possibility for early cannulation and no maturation requirement, with the more longterm advantages associated with AVFs, such as improved patency rates, and a reduced number of interventions and infections over time.

Moving on to outline the latest data with Axess from an EU first-in-human (FIH) study, Moll detailed that enrolment of a total of 20 patients across six sites has now been completed. As per

statistically superior to TLPP rates for PTA which were 42.2% and 22.7%.

A further subgroup analysis by lesion location focused on peri-anastomotic, cephalic arch and venous outflow lesions. For peri-anastamotic lesions, IN.PACT AV had a TLPP rate of 40.4% while PTA had a rate of 31.1% at 36 months. For cephalic arch lesions, the DCB arm saw a rate of 40.9% and the PTA arm one of 27.9%, while on venous outflow lesions the former had a rate of 45.6% and the latter of 25.5%. While patency was statistically superior at all lesion locations, the most notable effect was seen in peri-anastomotic and cephalic arch lesions.

For the first time, the 48-month all-cause mortality results were presented which again showed no evidence of a safety concern using a paclitaxel-eluting device in the AV access circuit. The mortality at 48 months was actually higher in the PTA arm at 41.8%, compared to to the DCB arm where mortality was 34.6%, although this did not reach statistical significance.

Summarising the findings, Holden stated that they demonstrated “sustained patency benefit for IN.PACT AV DCB compared to PTA in all subgroup analyses”, and he highlighted restenoses, perianastomotic and cephalic arch lesions in particular. Concluding his talk, he said: “Durable long-term data suggest the use of IN.PACT AV DCB as a standard of care for AVF maintenance in patients with end-stage kidney disease.”

follow-up data, which were available for all 20 patients, primary patency rates of 80% at six months and secondary patency rates of 100% at 12 months were achieved. The speaker also reported that no infections were observed. A full follow-up period of five years is now planned in these patients, and is ongoing.

Moll also provided attendees with insight based on surgeon feedback from the first 20 Axess implants—alluding to the fact it is a similar procedure to standard AVG implantation; the device being easier to suture and softer than traditional expanded polytetrafluoroethylene (ePTFE) products; and its improved adaptation to patient arteriotomy/venotomy proving “very helpful” in fragile vessels.

A prospective, single-arm EU pivotal trial of Axess is now also actively enrolling patients, at up to 25 sites spanning nine countries and with a total follow-up period of five years. Moll noted that enrolment in this larger-scale study began in Q4 2022. Among the key study endpoints is freedom from device-related serious adverse events during the first six months after implantation, and the pivotal trial is also powered to assess both primary and secondary patency rates.

See page 17 for more.

“Durable long-term data suggest the use of IN.PACT AV DCB as a standard of care for AVF maintenance [...]”

Andrew Holden

“This graft can bring a brighter future for the increasing number of patients who depend on dialysis treatments.”

Frans Moll

Thrombosis focus and interventional training ignite first CX renal interventions session

The renal interventions session at Charing Cross (CX) Symposium 2023 (25–27 April, London, UK) yielded a rich vein of education and audience participation on everything from stent positioning to interventional training. With speakers including Matthew Gibson (Berkshire Imaging, Reading, United Kingdom) and Georgia Georgopoulou (University Hospital of Patrai, Patras, Greece), its talks provided a wide snapshot of the renal space.

ONE EARLY PRESENTATION BY GIBSON SET OUT

“a real-world approach” to managing thrombosed haemodialysis access. Clotted access is usually preventable, Gibson said, and can be due to a “failure”. This failure could be the surgical or radiological formation technique, monitoring needling technique or homeostasis (dehydration/hypotension), Gibson added. He also established the particular problems raised by clotted access. Compared to a preventative fistulopasty, he said, a declotting procedure results in a worse patient experience, worse success and complications rates, and was more time- and resource-consuming. It also potentially poses the need for temporary access if delayed or unsuccessful.

But, he asked, what should you do when presented with access thrombosis? First, he urged listeners to “act quickly and effectively” to remove a thrombus and to treat the culprit lesion. Though there are a range of techniques available, there are no randomised controlled trials to guide choice of technique. While there have been meta-analyses performed, Gibson argued that there is “no clear winner” on the issue. This is where real-world considerations could help to expedite a decision.

In the real world, he said, clinical decision-making during the COVID-19 pandemic changed to favour methods that were both the least invasive and most likely to be successful—as well as less resource-intensive. He noted that this had led to a fall in declotting procedures, especially surgical declotting, per a report on access management during the pandemic published in the Journal of Vascular Access by Christopher Seet (Barts Health NHS Trust, London, United Kingdom) et al in 2021. Gibson’s concluding message was to “treat [thrombosis] quickly and effectively, but be realistic and think of the future”. He added that technique is “less important than availability, skill and enthusiasm”.

Presenting towards the end of the session was Georgopoulou, who detailed the Nephrology Partnership for Advancing Technology in Healthcare (N-PATH) interventional nephrology training programme. She described it as “the first European advanced training course in diagnostic and interventional nephrology”, explaining that it comprises component modules in molecular pathology, vascular access, medical ultrasound and peritoneal dialysis, each with hands-on training sessions in cities across Europe including Milan and Prague, while also including online educational resources.

How effective is cost effectiveness for dialysis patients?

Attendees at the CX renal interventions session were treated to two presentations exploring the issue of cost effectiveness in renal care—and whether it should take priority over outcomes. In the corner of cost effectiveness was Jeremy Crane (Hammersmith Hospital, London, UK), but before him came Alexandros Mallios (Hôpital Paris Saint-Joseph, Paris, France), who insisted that outcomes should come first.

Mallios began by opining that, in an ideal world, the question of whether outcomes should be the priority would demand only a very short presentation—one in which he simply answered “yes”. He then posed another question: how are the best outcomes defined? For the government, he suggested, the best outcome might be the cheapest, while for the nephrologist it might be the one that gets him safely back to his office without a call from the nurse that there is a problem. Surgeons might have their own definitions, too—but what about the patient?

Having presented all of these options, Mallios then questioned why there should be a conflict between outcomes and cost effectiveness. He stated: “Best results and cost effectiveness can be compatible as long as the system provides incentives and rewards the right kind of care—although in most countries it does not currently do so”.

Offering a scenario in which a surgeon follows guidelines and creates a non-dominant radiocephalic fistula, he suggested such a patient could feasibly need a series of percutaneous transluminal angioplasty (PTA) procedures as their fistula repeatedly fails to mature—with a total treatment cost of €20,000, by Mallios’ estimation of the cost in France.

This, he suggested, achieves neither cost effectiveness nor the best outcomes compared to other procedures that perhaps have a higher initial cost. In the audience participation section following Mallios’ presentation, Karen Stevenson (Glasgow, United Kingdom) put it that “failure is expensive”—though she added that some patients prefer a short-term and others a longterm treatment strategy—and adopting those strategies may mean using different procedures.

Speaking finally on cost effectiveness, Mallios concluded: “I’m convinced that the benefits of

doing a fistula that works for a long time, and which offers a good quality of life to patients, are multiple—if not always measurable.”

The case for cost effectiveness

Next came Crane, who wryly described his path to the podium to advocate for cost effectiveness as a “walk of shame”. Once he got there, however, he nevertheless built the case for “bang for buck” in kidney care. Cost effectiveness he defined as “the value of a healthcare intervention”—it is “about the ability to provide the best outcomes possible while also being financially viable”, which means getting the most possible out of the available resources.

Turning to how cost effectiveness is measured, Crane then raised quality-adjusted life years (QALYs) as the main metric of an intervention’s offer of disease limitation. He also highlighted non-monetary benefits as a component of cost-benefit analyses. The measurement of cost effectiveness is “in essence” the same across healthcare systems, he added, but there is variation between public and private healthcare systems.

“Why is this so particularly applicable to vascular access for dialysis?” he asked next. The answer, he said, was the “growing demand worldwide” for dialysis care, and said that a combination of aging populations and increasing diabetes rates have combined with better dialysis provision in some countries to increase numbers of patients.

New technologies such as the VasQ device (Laminate Medical), Crane said, could improve cost effectiveness by improving outcomes in dialysis access. Cost effectiveness “should not come at the expense of patient safety,” but he concluded that it “will play a pivotal role in helping more patients receive successful dialysis as the years roll on”.

“Best results and cost effectiveness can be compatible if the system provides incentives and rewards the right kind of care.”

Jeremy Crane

Alexandros Mallios

Matthew Gibson

Peritoneal dialysis underutilised “across the world” despite advantages

Peritoneal dialysis (PD) has a number of advantages over haemodialysis—yet with a few exceptions, it is underutilised in most countries. So went the argument of transplant surgeon Frank Dor (Hammersmith Hospital, London, UK) when he spoke as part of the first ever renal interventions session at Charing Cross (CX) Symposium (25—27 April, London, UK), which followed an earlier session on vascular access.

DOR STAKED OUT A CLAIM THAT PRE-EMPTIVE living donor kidney transplantation was the “most ideal” therapy for kidney disease patients, and added that kidney transplantation is generally preferred over dialysis for a variety of reasons. However, he said that each of these therapies had their own roles to play—often in the course of treatment of the same patient—and he emphasised that “many patients have contraindications for transplantation”. Some experience transplant failure when there is not another donor immediately available. Those receiving treatment for chronic kidney disease (CKD) can use many modalities during their journey as a kidney patient, he said.

“In terms of access for dialysis, there are not technically many contraindications,” Dor stated. “However, if you ask people their preferences—when they are given unbiased pre-dialysis education—about 50% opt for PD.” For this claim, he referenced a number of studies including Johanna C Korevaar (University of Amsterdam, Amsterdam, The Netherlands) et al’s from 2003. Nevertheless, only one region is listed as performing PD over 50% of the time—Hong Kong.

For a number of “complex” reasons, however, PD

remains “underutilised”, he argued, citing a list of patient-reported factors that lead them to favour the modality. Chief among them is the improved freedom and autonomy it provides, allowing them to more easily work and travel. It also relieves them of the need to visit a dialysis centre to receive treatment, allowing them to perform it at home—something hit upon again in the question and answer section after the presentation, where Dor said that PD and home haemodialysis both offered this advantage and were “complementary” rather than in competition, catering as they do to differing suitability in different patients.

PD also offers greater dietary freedom, with fewer fluid restrictions, as well as the “avoidance of painful needle sticks”. Those concerned about the appearance

DBB-EXA dialysis machine found less reliable for flow rate measurement than Transonic

The DBB-EXA dialysis machine (Nikkiso) consistently underestimates vascular access (VA) flow rates compared with the Transonic technique of measurement—that is the conclusion of a new study in the Journal of Vascular Access comparing the two methods.

THE REPORT, PUT TOGETHER BY LEAD author Georgios Kosmadakis (Aura Santé, Clermont-Ferrand, France) and colleagues, begins by setting out that the existing methods of measuring VA flow “are usually based on the indicator dilution theory”. Monitoring VA flow can, according to a study led by Loay Salman (Albany Medical College, Albany, USA) and published in Kidney International Reports in 2020, result in a reduced rate of thrombotic events in patients with fistulas.

Noting the results of Salman et al’s study, Kosmadakis and colleagues set out to compare the accuracy of the DBB-EXA and Transonic technologies for VA flow measurement. They devised an observational study including 65 patients, 38 of whom were male. The patients had a mean age of 72±10 years, and

VA flow was measured twice with DBB-EXA and twice with Transonic while they were undergoing dialysis. This was then repeated again seven days later.

With a total of 130 double measurements for each method on the first day, Transonic found a mean flow of 1413±715ml/ min while DBB-EXA found one of 1,297±664ml/min. Additionally, a Bland-Altman analysis found that the mean difference between the two methods was 159 ± 211 ml/min (limits of agreement: −274 and 572ml/min). Of the 130 DBB-EXA measurements, 81 were within 25% of those with Transonic, representing an accuracy rate of 62%.

Turning to the reproducibility of the results on different days, the authors add that mean difference in the Bland-Altman analysis was 29±620ml/

of an angioaccess site on their arm may also prefer it. From a clinical perspective, Dor makes the case that it presents an option that is cheaper with lower mortality rates, better cognitive function for patients, and preservation of urinary output for longer, while also better suiting elderly or frail patients, as well as transplant recipients.

Why, Dor asked, is PD nevertheless underutilised? He suggested in answer that “nephrology and surgical trainees are not properly trained” on the therapy, nor are patients properly informed. Adding that “haemodialysis facilities need to stay open,” he said there was therefore “a financial incentive for haemodialysis.” PD also presents several technical issues, with a “relatively high mechanical complication rate” and a 20% failure rate of PD catheter insertion—though these issues, he put forward, may be related to the shortage of proper training.

As part of the International Society of Peritoneal Dialysis (ISPD), Dor explained that the society’s guideline advises the use of advanced laparoscopic PD catheter insertion as a solution. This, he said, could improve PD catheter insertion through “thorough assessment of the peritoneal cavity”, as well as a maximisation of surgical working space, among other advantages. Speaking to this newspaper, he said: “For the advanced laparoscopic technique, it is equally important that adjunctive procedures that would enable better PD catheter survival can be done during the insertion operation, which cannot be done using different techniques.”

He noted that the yearly course he chairs on behalf of the ISPD in Vienna, “ISPD PD University for Surgeons— Europe”, was helping to contribute to improved provision of PD access.

1,297 ±  664ml/ min

min (limits of agreement: −1,186 and 1,244ml/ min) for the Transonic measurements and 132±625ml/min (limits of agreement: −1,092 and 1,356ml/min) for the DBB-EXA measurements.

The authors also note that the measurements on two different days “were within 25% of each other for 52 of the 65 patients (80%) with the Transonic method, and for 35 of the 65 patients (54%) with the DBB-EXA method”.

The authors describe their findings on reproducibility as “poor for both methods” in different-day measurements. They conclude that DBB-EXA “underestimates VA flow rates compared to the Transonic technique” and describe its 62% accuracy rate as “limited”. Ultimately, they state: “The DBB-EXA method could be used as a simple tool for a rough estimate of VA flow rates but cannot replace the Transonic reference method.”

“If you ask people their preferences—when they are given unbiased pre-dialysis education—about 50% opt for PD.”

Georgios Kosmadakis

“The DBB-EXA method could be used as a simple tool for a rough estimate of VA flow rates but cannot replace the Transonic reference method.”

EndoAVF usually less cost effective compared with sAVF, study finds

The Society for Clinical Vascular Surgery (SCVS) 50th Annual Symposium (25–29 March, Miami, USA) hosted a series of abstract presentations. Among them was one by Bianca Mulaney and colleagues including Elizabeth George (both Stanford University, Stanford, USA) on the cost effectiveness of endovascular arteriovenous fistula (endoAVF) creation when compared with surgical AVF (sAVF) creation.

Mulaney began her presentation by telling the SCVS audience that around US$2.8 billion is estimated to be spent on vascular access and its complications each year in the USA, which she said amounts to “a significant cost burden” as well as “a significant portion of the vascular surgeon’s caseload”. Though endoAVF has demonstrated lower rates of complications such as steal syndrome in some studies, “the clinical and financial impact of endoAVF remains uncertain”, according to Mulaney. It is this uncertainty that the study she led aimed to resolve.

“The one way we can get at this question, in the absence of concrete data from a randomised controlled trial (RCT), is a cost-effectiveness analysis aimed at forecasting the outcomes of the two approaches,” Mulaney said.

The parameters for her cost effectiveness analysis came from a systematic review she conducted to obtain data on technical success of the procedures along with maturation, patency,

and utility values, as well as data from the Medicare 2022 fee schedule for costs associated with the two procedures. She presented a decision tree linked to a probabilistic cohort state-transition model comparing endoAVF and sAVF outcomes over five years. Further outlining the study authors’ methods, the abstract states that they used “a five-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 (WTP) threshold of US$50,000".

Setting out the study’s findings, Mulaney stated clearly that endoAVF was found not to be cost effective when compared with sAVF. “Although endoAVF increases QALYs by the equivalent of about one-and-a-half months of extra life for the average patient with end-stage renal disease (ESRD),” she added, “it comes at a significantly greater cost.” Comparing endoAVF (per capita US$30,129 costs, 2.19 QALYs; 65% patent at five years) with sAVF (per capita US$12,987 costs, 2.11 QALYs; 66% patent at five years) generated an incremental cost-effectiveness ratio (ICER) of US$227,504 per QALY gained.

However, Mulaney specified that a series of one-way sensitivity analyses revealed that, when several variables reached certain thresholds, endoAVF did become cost effective. When the endoAVF maturation rate is greater than 90%, for instance, it became cost effective compared with sAVF. Other examples include when the

A call to arms: Reuse of mature venous conduits urged

“Recycle that vein!”—that was the appeal from the authors of a new study that trialled the explantation of mature arteriovenous fistulas (AVFs) from patients with venous outflow obstruction in one extremity and translocation of them to the contralateral extremity. Led by Guillermo A Escobar (Emory University, Atlanta, USA), the small study’s abstract was put to the audience at the SCVS symposium and presented by Brandi Mize (Emory University).

THE AUTHORS NOTE THAT unresolvable venous obstruction in cases of a patent AVF brings extremity dysfunction and pain, traditionally followed by the ligation and disposal of a mature vein. This leads to “prolonged dialysis catheter dependence” as a new vein is sought for maturation or a prosthetic is used. They

say it can be “especially devastating” when there is not an appropriate alternative vein for access as catheter dependence leads to further central stenosis. Escobar et al sought to establish whether the translocation of even “potentially aneurysmal or thrombus-laden” AVFs was an effective treatment for the swelling associated with venous obstruction as well as a means of providing “early, autologous access” to reduce patients’ dependence on dialysis catheters. They asked: “Why ligate a >10mm autologous conduit?”

The authors removed matured AVF in patients with venous outflow obstruction and repaired them ex vivo if needed. The repairs consisted of thrombectomy, endarterectomy, resection/plication of aneurysms with end-to-end reanastomosis, or any combination. Following this, they were then reimplanted in patients’ contralateral extremities to form a new AVF.

They evaluated four patients facing

initial cost of sAVF creation exceeds endoAVF by at least US$600, the additional QALYs gained from endoAVF exceeds 0.12 QALYs/year and when sAVF maturation rate is beneath 65%.

The abstract presented by Mulaney ascribes endoAVF’s inferior cost effectiveness when modelling five-year outcomes to the “four times higher up-front cost for endoAVF creation as well as a relatively low initial maturation rate for endoAVF”. Mulaney expanded on this, putting forward the suggestion that an RCT is “definitely warranted” to further examine when endoAVF may be more cost effective. Responding to audience questions, Mulaney highlighted maturation rates as something which the study found to be having a particular impact on cost effectiveness. She called on device companies to improve device capabilities to increase maturation rates. Looking forward, she also said she would welcome future studies examining the differences between specific endoAVF devices.

occluded central or extremity outflow veins despite multiple attempts at endovascular resolution. “All patients had complete resolution of their original symptoms,” Escobar et al state. All went from experiencing “severe swelling, pain and a disfigured extremity”—even with “elephantiasis and ulceration of the arm”— to having a functional access following the procedure, with a mean time to use of 44 days (median 37) and as early as 20 days in their study, though Escobar et al add that earlier access is likely “feasible in as little as 14 days”. Primary patency was a mean of 315 days (median 300). Though three of the four needed repair or partial resection of AVF aneurysms before the implantation of their fistula in the contralateral extremity, only one required reintervention in the form of angioplasty of outflow vein without interruption of dialysis.

In their conclusion, the authors state: “Translocation of mature venous conduits to new sites seems very successful even if they require repair/resection of aneurysmal portions.” They note that “surgical times are long”, as the harvest, repair and reimplantation takes a mean time of almost eight hours. The procedure also demands “meticulous technical skill” for the repair and anastomosis of what they call “a very mismatched vein to a radial artery”, but they say that it appears to offer resolution of symptoms and the creation of a functional, autologous access.

“In addition, there is short catheter dependence compared to traditional approaches of ligation, recreation and awaiting unpredictable AVF maturity,” they add. Speaking to Renal Interventions, they suggest the findings offer a “paradigm shift” away from ligating mature AVFs and instead “recycling” them: “We believe that discarding usable, autologous venous conduits should be discouraged despite the technical challenges.”

“The one way we can get at this question, in the absence of concrete data from a randomised controlled trial (RCT), is a cost effectiveness analysis.”

“We believe that discarding usable, autologous venous conduits should be discouraged despite the technical challenges.”

Guillermo A Escobar

Brandi Mize

Bianca Mulaney

Brian Rifkin

kidney replacement therapy if necessary and desired by the patient, or encouraging kidney transplantation and home dialysis. So: would it not make more sense, given our lizard brain’s need for dopamine, to flip reimbursement on its head and incentivise pre-dialysis CKD care? Well, change is hard.

There are still many obstacles to be negotiated before VBC models perform as intended. Slowing dialysis initiation is a clinical and economical goal, but the incentives for pre-dialysis care have not been well established, and its development in some cases may be unfavourable for providers. Incentives and protocols matter, as was shown with ESAs, as only about 40% of patients with CKD are on an angiotensin-converting-enzyme (ACE) inhibitor/angiotensin II receptor blockers (ARBs), a standard of CKD care.6 Thus, there is a need for direct VBC economic incentives to physicians for initiating evidence-based CKD treatments.

Aligning incentives to improve patient outcomes

Doctors are human (OK, Captain Obvious). We are subject to the same psychological pressures that drive people’s worst impulses. Did you think physicians were above biases and outside influences? That we are somehow “superhuman”, and always do what is in our patient’s best interest?

There are examples in clinical decision making that make our faults quite obvious. Many of them are associated with a shift in clinical care directly related to payment models. In an ideal world, incentives (including monetary payments) would align both patient and physician interests. Let me give you an example from the not-too-distant past in the treatment of anaemia in patients on dialysis.

Epoetin came to market in 1989, and cut transfusion rates by 50% one year after its introduction. I have been a private practice nephrologist in the USA since the early 2000s: back in those days, erythropoietin stimulating agents (ESAs) were already ubiquitous, and were a separately billable item (more ESA use meant larger payments). We knew from the 1998 Normal Hematocrit Trial1 that normalisation of haematocrits in dialysis patients was associated with worse cardiovascular outcomes. Additional studies2 looked at increased haemoglobins over 13g/ dL in dialysis patients, though none of these were able to show improved mortality or cardiovascular outcomes.

Unfortunately, the available evidence did little to slow the increasing doses and increasing average haemoglobins in dialysis patients. Then, in 2006, the Kidney Disease Outcomes Quality Initiative (KDOQI) updated their guidelines on anaemia. These guidelines were underwritten by Amgen, the manufacturer of epoetin alfa. The guidelines, in the face of the above data, actually increased the target haemoglobin from 11–12 to 11–13g/dL. The most amazing thing about the detour to haemoglobins of 13 and beyond is that we knew everything we needed to know from 1998’s Normal Hematocrit Trial. Much of the enthusiasm for high haematocrits was finally derailed by CHOIR, CREATE, and then TREAT3 (in patients with CKD not on dialysis).

These studies convinced the most important people of all, the government payers for ESAs, to finally follow the data. On 1 January 2011, the dialysis “bundle” was initiated. It brought about a new frugality and cost consciousness in the use of medications and other resources in the management of patients with ESKD. Dialysis providers were challenged to control costs, while providing quality care.4 As a result of the bundle, medicines suddenly became a cost centre versus a profit centre, and, as in many other practices, our use of ESAs plummeted by 40–45% in the following

months. Finally, in February 2016, Glenn Chertow and colleagues5 looked at the rates of cardiovascular outcomes and found that, in 2011 and 2012 (the years with the biggest fall in average haemoglobins), heart failure, stroke, and venous thrombosis were all lower than predicted. Taking our foot off the ESA accelerator appeared to be benefitting patients. The decreased use of ESAs ultimately occurred well after the clinical evidence suggested it should, and much closer, rather, to the change in reimbursement. Would this frugality in ESA use have occurred without the changes in payment incentives?

Which brings us to the subject of value-based care (VBC) models in nephrology. This is the latest iteration of incentives, or penalties, that attempt to align physician payments with patient care. Many accountable care organisations (ACOs) have been using VBC guidelines for shared savings bonus payments. Our ACO monitors VBC compliance by examining the rates of recommended procedures completed for common disorders. This has led to more cancer screenings (cancer prevention), diabetic eye screenings (blindness prevention) and improved use of statins and beta-blockers in patients with cardiac disease (cardiovascular death prevention). This in turn helps to maintain “per patient” budgets at or below estimated costs by early detection or slowing chronic disease progression.

Value-based care in nephrology

Most physicians would agree that prevention is preferable to treatment in most diseases. So, why should nephrology care about VBC models? Despite our “best efforts”, currently one in seven people in the USA have CKD, and 40% of individuals nearing dialysis are not aware of their diagnosis of CKD. More than 50% of patients “crash” into dialysis without prior CKD care. While the annual cost of CKD for Medicare patients is US$90 billion (for 37 million patients), the cost of ESKD is US$37 billion (for roughly 500,000 patients).

Most physicians would also agree the real focus of nephrology should include slowing CKD stage 4/5 progression, patient education, optimising dialysis initiation and decreasing the total cost of care. Unfortunately, we USA-based private practice nephrologists have been functioning under a very perverse reimbursement system. Currently, there are more financial incentives for initiation of dialysis rather than for prolonging the course of CKD prior to initiation of dialysis. In addition, in contrast to the highly structured processes in place for dialysis care, there are few organised, well-funded programmes that target preventing or slowing progression of kidney disease among individuals with CKD. Nor are there such programmes promoting a smooth transition to

The medical industry is moving toward VBC and, if doctors do not get involved, someone else will. Currently, population health programmes, such as Monogram Health, receive payments to decrease patient expenditures through at-home patient education. Unfortunately, there is sometimes poor alignment with the patient’s primary nephrologist, and these organisations often have a narrow focus based solely upon economic factors. There will have to be better co-ordination on behalf of the patient for education, treatment initiation and dialysis choices. Finally, success in VBC requires physician engagement and significant data reporting in order to get to incentives, both of which may carry significant upfront cost. In addition, most VBC programmes will also ask physicians to take on risk to receive performance incentives, making financial benefits murkier.

VBC models have many moving parts, and input from multiple sources. Policy makers must consider performance-based adjustments based upon socioeconomic disparities, attempt to eliminate barriers to education services like co-pays, and determine ways to make VBC models viable for all size practices and population distributions. Close co-operation between policymakers, economists and nephrologists is needed to ensure a high quality of pre-dialysis care that has a meaningful benefit to patients. Perhaps we can learn from the mistakes of the past and move more quickly to programmes that benefit physicians for making better choices for our patients. VBC models are a tool that will require some further adjustments but will, in the future, hopefully align physician incentives with patient care goals.

References:

1. Besarab A, Bolton WK, Browne JK, et al. The effects of normal as compared with low hematocrit values in patients with cardiac disease who are receiving hemodialysis and epoetin. N Engl J Med. 1998 Aug 27;339(9):58490. doi: 10.1056/NEJM199808273390903. PMID: 9718377.

2. Furuland H, Linde T, Ahlmén J, et al. A randomized controlled trial of haemoglobin normalization with epoetin alfa in pre-dialysis and dialysis patients. Nephrol Dial Transplant . 2003 Feb;18(2):353-61. doi:10.1093/ ndt/18.2.353. PMID: 12543892.

3. Landmark Trials in Anemia & Kidney Disease - Renal Fellow Network, www.renalfellow.org/2020/02/19/landmark-trials-in-amenia-kidney-disease/, downloaded 4/2/23.

4. Charnow JA. How “Bundling” Changed Dialysis Care. Renal and Urology News. 3/2/17.

5. Chertow GM, Liu J, Monda KL, et al. Epoetin Alfa and Outcomes in Dialysis amid Regulatory and Payment Reform. J Am Soc Nephrol. 2016 Oct;27(10):3129-38. doi: 10.1681/ASN.2015111232. Epub 2016 Feb 25. PMID: 26917691; PMCID: PMC5042674.

6. Murphy DP, Drawz PE, Foley RN. Trends in Angiotensin-Converting Enzyme Inhibitor and Angiotensin II Receptor Blocker Use among Those with Impaired Kidney Function in the United States. J Am Soc Nephrol. 2019 Jul;30(7):1314-1321. doi: 10.1681/ASN.2018100971. Epub 2019 Jun 5. PMID: 31167823; PMCID: PMC6622408.

The author stated no relevant disclosures.

“Slowing dialysis initiation is a clinical and economical goal, but the incentives for pre-dialysis care have not been well established.”

Brian Rifkin is a nephrologist at Hattiesburg Clinic (Hattiesburg, USA). He is an ASDIN member.

People in the USA who have CKD

1 in 7

Individuals nearing dialysis who are not aware of their condition

40%

ESRD strongly associated with adverse limb events in new study

A new investigation into the association between end-stage renal disease (ESRD) and major adverse limb events (MALEs) has found that not only is it strong, but ESRD is particularly associated with below-knee amputation. The details of the study were presented at the Society of Interventional Radiology (SIR) Annual Scientific Meeting (4–9 March, Phoenix, USA).

THE AUTHORS, LED BY YONATAN Babore (Perelman School of Medicine at the University of Pennsylvania, Philadelphia, USA), state in their abstract that their focus was on uncovering the likelihood of MALEs and amputation with ESRD specifically in chronic limb-threatening ischaemia (CLTI) patients who were undergoing percutaneous vascular intervention (PVI) for their condition. They therefore designed a study in which they performed propensity score matching with the data from two contemporaneous cohorts, both of whom were undergoing PVI for symptomatic CLTI. The data was gathered from 2012 to 2022, and the cohorts were differentiated by ESRD status.

The database used included 628 patients, who underwent 1,297 lower extremity revascularisation procedures. These were then matched to 147 patients. Outcomes from procedures on 180 limbs were considered in total— 90 limbs for each group—while both Kaplan-Meier and Cox proportional hazard analyses were performed with the data, intended to examine the effect of the presence of ESRD on the probability of MALEs. MALEs themselves were stratified into reintervention, meaning PVI or bypass surgery, as well as major amputation. This latter category was subdivided into aboveand below-knee amputation.

Babore et al found that, following a PVI procedure, 31.3% of patients in the matched cohorts experienced a MALE. Among those experiencing ESRD, 45.7% experienced a MALE while only 18.2% of those without ESRD did so. On major amputation, patients without ESRD experienced an event at a rate of 5.2%, while those with the condition did so at the higher rate of 27.1%. The proportional hazard analysis found that ESRD “was an independent predictor of MALE” (hazard ratio [HR] 3.15; 95%, confidence interval [CI] 1.58–6.29; p ¼ 0.001), major amputation (HR 7.00; 95% CI 2.06–23.79; p ¼ 0.002), and below-knee amputation (HR 7.56; 95% CI 1.71–33.50; p ¼ 0.008).

Summarising the findings, the authors state that ESRD is “strongly predictive” of both MALE and major amputation for CLTI patients who are receiving PVI procedures, and particularly so in the case of below-knee amputation. Finally, they look forward, calling for more research: “These patients warrant closer follow-up, and new methods may become necessary to predict and further reduce their amputation risk.”

The AVeNEW study, a 24-month multicentre, international, prospective and randomised clinical trial has published results investigating percutaneous transluminal angioplasty (PTA) compared to PTA with placement of a covered stent for the treatment of arteriovenous fistula (AVF) stenosis.

The covered stent group had improved target lesion primary patency (TLPP) compared to PTA alone, with comparable safety. Bart Dolmatch (Palo Alto Medical Foundation, Mountain View, USA) led the 24-site study that included 280 patients. The AVeNEW results have led to US Food and Drug Administration (FDA) clearance of the Covera covered stent (BD) for use in AVFs. In the authors’ view, the results demonstrated both safety and improved outcomes when using a covered stent to treat AVF stenosis in upper arm dialysis AVFs.

Stenosis development can limit flow in a haemodialysis arteriovenous fistula (AVF), say the authors of the study, which was published in Kidney International. This can lead to struggles with cannulation, spontaneous access thrombosis and other complications including “prolonged bleeding”—not to mention “ineffective dialysis” itself, they note.

Though angioplasty is often used to treat AVF stenosis, there have been randomised clinical trials showing that placing a covered stent following angioplasty of arteriovenous graft (AVG) venous anastomotic stenosis “affords superior target lesion primary patency (TLPP) compared to PTA alone”. In light of these results, the authors sought to examine if covered stent placement would improve outcomes when treating stenoses in AVFs, and conducted “the first large, prospective, randomised study” to address this question.

In total, 280 patients across 24 sites in the USA, Europe, Australia, and New Zealand were randomised in the trial, with 142 patients in the covered stent group and 138 in the PTA group. Dolmatch et al set out a few of the most common comorbidities among the cohort, including “hypertension (97.1%), dyslipidaemia (97.1%), type 2 diabetes mellitus (69.6%), coronary artery disease (35%), congestive heart failure (26.8%), and peripheral arterial disease (18.9%)”. The majority of those enrolled had an

AVF in their upper arm (93.6%), with slightly more than half of the randomised AVFs having a brachiocephalic configuration (57.9%). Target lesions were mostly restenotic (73.2%), while slightly more than half of the target stenoses were in the cephalic vein arch (52.9%).

The primary safety outcome was 30-day freedom from adverse events requiring reintervention or surgery, or that facilitated or caused hospitalisation or death. The primary patency outcome was target lesion primary patency (TLPP) at six months, which was lost if there was a clinically-driven reintervention at the target lesion site, or abandonment of the AVF. Secondary hypothesis-tested outcomes included technically successful placement of the covered stent, TLPP at 12 months, and access circuit primary patency (ACPP) at six months. Other outcomes were observational and included TLPP and ACPP out to 24 months.

Regarding the primary outcome measures, the covered stent group demonstrated non-inferior safety to the angioplasty group (non-inferiority p=0.002) at 30 days, while TLPP was superior to the angioplasty group (78.7% vs. 47.9%) at 180 days (modified intention to treat analysis; Kaplan-Meier survival analysis; p<0.001). ACPP, while numerically better for the covered stent group, was not statistically superior at six, 12, or 24 months. The authors note:

“While superior ACPP would have been desirable, it was not surprising that circuit patency was not statistically better for the covered stent group [since] circuit patency is multifactorial and represents the combined impact of target site patency, new stenoses, AVF thrombosis, and non-target stenoses treated at the index procedure that recur.”

Limitations included the fact that investigators and staff were not blinded to treatment allocation, and 24-month attrition was 21% (largely due to mortality) which reduced the study population available for analysis. Regarding the ongoing challenge of deciding when to use PTA, covered stents, drug-coated balloons, or other methods to treat AVF stenosis, the authors call for properly powered comparative randomised studies. Nevertheless, the authors conclude that the AVeNEW trial demonstrated that the Covera stent offered “statistically superior TLPP results and modest clinical benefit for patients” when compared to PTA alone.

Led by Hyangkyoung Kim (Ewha Womans University Medical Center, Seoul, South Korea) and featuring corresponding author Hoon Suk Park (The Catholic University of Korea School of Medicine, Seoul, South Korea), a study published in Hemodialysis International has found that arteriovenous fistulas (AVFs) are a safer and more effective option for end-stage kidney disease (ESKD) patients aged ≥ 65 years than arteriovenous grafts (AVGs).

THE STUDY SOUGHT TO ESTABLISH THE outcomes from the two procedures in this specific population in response to the “fistula first” initiative, which they describe as “controversial in patients ≥ 65 years”. This population, they point out, is one that makes up nearly half of those who initiate haemodialysis.

Previous studies have raised questions about the advantages of AVFs in older populations. These include a 2013 study by Ranil N DeSilva (Beth Israel Deaconess Medical Center, Boston, USA) et al, which suggested that “a competing strategy of AVG” should be considered for elderly patients, finding no statistically significant advantage on mortality for AVF over AVG.

Kim and Park carried out a retrospective review of data from South

Korea’s National Health Insurance Service relating to 41,989 patients aged ≥ 65 years. The patients’ characteristics and outcomes, encompassing “vascular access patencies, risk factors associated with patencies, and patient survival between AVF and AVG”, were then compared.

Among those patients, 28,467 received a permanent AV access with an AVF while 13,522 received an AVG. The AVF group demonstrated superior primary, primary-assisted and secondary patencies (all p<0.001), while they also showed better rates of survival (p<0.001). A Cox regression analysis found that AVG was a risk factor relative to AVF for all-cause mortality (adjusted hazard ratio [HR]: 1.307; 95% confidence interval [CI]: 1.272–1.343; p<0.001) as well as primary patency (adjusted HR: 1.745; 95% CI: 1.701–1.790; p<0.001). Similarly, it was also a risk factor on primary-assisted patency (adjusted HR: 2.163; 95% CI: 2.095–2.233; p<0.001) and secondary patency (adjusted HR: 3.718; 95% CI: 3.533–3.913; p<0.001).

The authors state clearly that their results point to AVF as a markedly superior option for permanent access for haemodialysis, even in those aged ≥ 65 years. It should be “strongly considered” for those in this age group with ESKD, argue Kim and Park, who suggest finally that “the age limit for AVF creation in ESKD patients should be adjusted upwards”.

Covered stent improves AVF angioplasty outcomes in new trial

Age ceiling for AVF “should be adjusted upwards”

Hyangkyoung Kim Hoon Suk Park

Bart Dolmatch

Yonatan Babore

Daniel Patel

American Society of Diagnostic and Interventional Nephrology (ASDIN) certification and accreditation

chairman Daniel Patel is the medical director for interventional nephrology at the VolusiaFlagler Vascular Center, which he founded in his hometown of Daytona Beach, USA. He speaks to Renal Interventions to discuss everything interventional nephrology (IN), connecting with patients, and the unlikely similarity between snowboarding and doing procedures.

What drew you to a career in medicine and IN?

My father is a retired nephrologist and was part of bringing dialysis to Central Florida in the late 1970s. Growing up, I saw the passion and commitment he had towards his patients— which inspired me to go into medicine. He never pointed me towards it, but he definitely served as a role model for me as I went through my training. He always genuinely enjoyed the science and art of medicine, and was well respected in his field. The inflection point came at the end of high school, when I had been accepted to a business programme at an Ivy League university, and I had also been accepted into an accelerated combined medical programme at the University of Miami. It was a difficult decision at the time, but I chose a path in medicine—I wanted to pursue a career in helping others.

Who are your mentors and who has inspired you during your career?

As a third-year medical student in 2003, I attended an internal medicine grand rounds on IN by Arif Asif. At the time, he was a pioneer in the field—I was amazed at the procedures he was performing, and he allowed me to spend some time in his lab at the University of Miami. He took me under his wing, and greatly influenced my early career. I later learned that as a trainee Asif had been considering a career in transplant nephrology, but had been encouraged to consider a career in IN by a friendly physician he met at a Florida Society of Nephrology meeting—who we later learned was my father. I was also fortunate to have been accepted to Emory University in Atlanta, which had a thriving IN programme at the time led by Jack Work, Monnie Wasse, and Vandana Niyyar. As another pioneer in the field, Work supported my pursuit of IN training, and was a fantastic mentor.

How do you see the progress and future of IN?

There has been significant progress in the field of IN over my career. Early battles with surgeons and interventional radiologists have given way to a much more collaborative and congenial relationship between the specialties. We all deal with a very complex patient population, and dialysis access can be a challenging area to fully understand and manage. I think there is a shared passion for taking care of these patients—and this shared commitment has brought the various fields together. Dialysis access could be considered its own specialty, and demand for such specialists will increase as the population of patients needing access care increases. Looking to the future, advances in technology and treatments along with growing interest in research in vascular access have made the field more and more exciting.

What do you hope to see in kidney care through the work of ASDIN?

ASDIN has been a fundamental part of my career, from my early days as a student to my current active involvement with the organisation. ASDIN remains as the foundation for IN in the USA, and now has gained an international reach to help support interventional nephrologists worldwide. The scope has gone beyond only nephrologists, with more and more surgical and radiology involvement in the society over the years as well. Nurses are now also represented on the council, and I hope to see a continued focus on research, mentorship, and patient advocacy. Continued strong support for reimbursement will be vital to maintain the success of the field, which ultimately will allow for quality access to care for our patients. ASDIN has collaborated better with other vascular societies over the years as well, which has fostered a better foundation for research and teaching in the field of vascular access as a whole.

What changes would you like to see in dialysis access care?

Ideally, we will see continued investment and focus on innovation to improve outcomes. But these investments must be something that healthcare systems will pay for. Without adequate reimbursement, there will be a stifling of further investment into dialysis access innovation. A more ideal scenario would be greater access to renal transplants and less dialysis in general, but until we get there we will continue to need innovation in dialysis access care.

What is your current view of the drug-coated balloon (DCB) space?

The conventional management of dialysis access stenosis with plain balloon angioplasty is a relatively crude treatment approach, with poor long-term patency and frequent recurrent stenosis. Treating dialysis access stenosis at a more fundamental biological level is intriguing, and the DCB space is an exciting new area of development in the field of dialysis access management. The IN.PACT AV paclitaxel data is particularly compelling, showing significant long-term benefits of DCB use in AV access lesions, but the lack of reimbursement in the United States is very frustrating. Ideally, there would be better payment systems which recognise the research showing DCBs’ cost effectiveness, and that would better allow for their application.

What advice would you give to young physicians interested in IN and vascular access?

Unfortunately, training in IN and vascular access in general is somewhat limited in the USA and across the world. Only a handful of academic centres in the USA even offer training in IN, and fewer and fewer academic interventional radiology and vascular surgery programmes have specific dedication to dialysis access. Therefore, I would recommend trainees and even established physicians go to vascular access meetings and get involved with dialysis access societies. I attended my first ASDIN meeting as a medical student, and regularly attended all the major dialysis access meetings in the USA. Not only are these meetings valuable for all the learning opportunities, but the contacts and friendships that you make at these meetings can last a lifetime—and it is good to share ideas and cases with colleagues, particularly early on in your career.

What do you see as the biggest unresolved question in kidney care?

I think we need a better understanding of the nature of dialysis access stenosis, and the best management options. For years, our main tool has been plain-balloon angioplasty. Drug coatings have been introduced, but we are essentially applying drug treatments that were designed for arterial stenosis to the dialysis access. Is there a better drug to treat dialysis access stenosis? Is dialysis access stenosis different on a biological level than arterial stenosis? I suspect that there is a heterogeneity to dialysis access stenosis, and we may be treating neointimal hyperplasia, calcification, scar tissue and/or a combination of pathologies leading to stenosis. Central lesions may be different biologically than peripheral lesions. If we can better understand the under-

Fact file

Current appointments:

Medical director, interventional nephrology, VolusiaFlagler Vascular Center (Daytona Beach, USA)

Consultation Nephrology, Nephrology Consultants PA, (Ormond Beach, USA)

Education:

1997–1999: Honours Programme in Medical Education (Six-year accelerated medical programme)

2000–04: University of Miami School of Medicine

2009: Nephrology and Interventional Nephrology fellowship, Emory University

Honours (selected):

2005: American Society of Nephrology Resident’s programme travel grant for 2005 annual meeting

2006: American College of Physicians, travel grants for Advocacy Meetings in Washington DC

2007: University of Miami Department of Medicine, “Eliseo Perez –Sable M.D.”

Professionalism Award

2007: University of Miami, Pat Caralis Award, Ethics and Professionalism

2007: ASDIN member

2008: Emory University, Fellow of the Year award

2016: ASDIN fellow

2018: Journal of Vascular Access editorial board member

2022: Chairman, ASDIN Credentialing Committee

lying pathophysiology, we may be able to better tailor treatments for access stenosis. Stent grafts have been revolutionary in the management of dialysis access grafts, and studies are now demonstrating more compelling applications in AV fistulas. Further research here could help us achieve more durable outcomes in AV access management.

What is your philosophy as a physician?

I was always trained to have a “patient-first” mentality, and this manifests in many ways. It is my responsibility to try to stay as cutting-edge and up to date as possible to provide the highest-quality care I can. At the end of the day it is about making a connection with the patient. Our patients come from all walks of life, but they all share the burden of a significant disease state. Making that personal connection makes

the doctor-patient relationship much more meaningful on both sides. We play music in our centre—usually classics from the seventies and eighties that I heard as a kid, like Elton John, Stevie Wonder and the Eagles—and that puts the patients at ease. At the end of the day, it is a privilege to help these patients, and it is an honour and responsibility to be able to do it.

What are your interests outside of medicine?

As I get older, I really enjoy learning new things again. Getting out of my element and learning new things keeps life fun. I am learning to race cars, and I am also an avid snowboarder. Perfecting a corner on a race track or refining skills on a snowboard are great feelings, and they take me back to the feeling I had when I did my first procedures and learned new techniques. I also love to travel with my family, my wife and two girls.

Illustration by: Andy Watt / NB Illustration

“I think we need a better understanding of the nature of dialysis access stenosis, and the best management options [...] Drug coatings have been introduced, but we are essentially applying drug treatments that were designed for arterial stenosis to the dialysis access.”

Andrew Frankel

SGLT2 inhibitor guideline update builds on new evidence

AT THIS YEAR’S UK KIDNEY WEEK (UKKW) event (5–7 June, Newport, UK), Will Herrington (University of Oxford, Oxford, UK) will be presenting on the EMPA Kidney study at a plenary session, and will be referencing how this study has influenced the new UK Guideline Group recommendations on how sodium glucose co-transporter 2 inhibitors (SGLT2i) should be used in the treatment of chronic kidney disease (CKD), on which I was also an author.

Over the last 20 years there has been year-on-year growth in the number of people with CKD progressing to end-stage kidney failure and requiring either a kidney transplant or dialysis.

Katie Wong

The response must be to identify those individuals earlier and optimise their therapy with interventions that reduce the progression of their kidney disease. The factors that have proven to be central to optimisation and treatment of CKD include better glucose control, blood pressure control and the use of inhibitors of the renin aldosterone angiotensin system (RAASi). In addition, careful attention to cardiovascular risk is important to reduce the increased cardiovascular complications associated with CKD. These treatments have been augmented by publications that have demonstrated the significant benefit that SGLT2i have on progression of CKD and,

additionally, their benefits in relation to prevention of heart failure progression. In response to this important information, in September 2021 the UK Kidney Association (UKKA) published evidencebased guidance on the use of these agents in people with kidney disease. However, the field has been rapidly changing with the publication of two further important large trials in 2022: DELIVER, which investigated the use of the SGLT2i dapagliflozin in people with heart failure with preserved or mildly reduced ejection fraction, and EMPA-KIDNEY, which investigated the use of empagliflozin in people with CKD including people with and without diabetes and people with and without albuminuria. The results from these trials and an additional meta-analysis of the totality of evidence has greatly expanded our understanding of the uses of SGLT2i and have increased the strength of evidence on which to make recommendations for use. Because of this an early update of the UKKA Guidance was required and has now been delivered.

The updated guideline maintains its original structure but has now also been published in the format of an interactive PDF which makes it much easier to navigate the guideline in order to find both the information on treatment recommendations and also to review the rationale and evidence to support the recommendations within that guideline.

The latest data has resulted in a broadening of the recommendations covering the groups of people who would benefit from the use of SGLT2i. The updated guideline extends the use of these agents to people both with and without diabe-

tes and evidence of kidney disease. For people with diabetes and any evidence of kidney disease—or indeed high cardiovascular risk—there is stronger evidence to support the use of SGLT2i. In regard to people without diabetes and CKD (people with a glomerular filtration rate [GFR] that is <60 and/or proteinuria), the guideline has extended the recommendations to use SGLT2i in those with lower degrees of proteinuria based on the evidence that SGLT2i slows the rate of decline in GFR thereby delaying the requirement for end-stage kidney failure treatment for this group of individuals. These benefits are in addition to their general benefits in relation to prevention of heart failure. There is also now evidence to support the use of SGLT2i in people with lower degrees of kidney function and, although the grade of evidence is not as strong as for people with GFR>20, the guideline suggests that consideration is given to the use of SGLT2i in people with GFR<20.

Implementation of the recommendations from these guidelines should have a significant effect on the long-term risk of CKD and provide significant population benefit as well as improving the longterm outlook for many individuals with CKD. The implementation of these recommendations will become a priority for the healthcare community in discussion with those individuals with CKD.

Andrew Frankel is consultant physician and nephrologist at Imperial College Healthcare NHS Trust (London, UK)

The author stated no relevant disclosures.

Improving our data

We are constantly working to make sure the data we collect is as in-depth and as up-todate as possible. We have added 362,503 kidney function results to the RaDaR database in the last six months using older data supplied by renal units. We now have a total of over 2.1 million kidney function readings stretching back over 40 years to the 1980’s for some participants.

The UK National Registry of Rare Kidney Diseases (RaDaR) at UK Kidney Week

OUR TEAM TEAM BEHIND THE UK National Registry of Rare Kidney Disease (RaDaR) are presenting the results of several research projects at UKKW. I will set out some of what they will discuss, what is possible with RaDaR data, and what RaDaR might be capable of in the future.

A rare disease is defined in Europe as a condition affecting less than one in 2,000 people. As rare kidney diseases only impact a small number of people, it can be difficult to find reliable information on them. RaDaR was formed

to help provide detailed information on rare kidney conditions for patients and clinicians. It collects information about people living with 30 rare kidney diseases and is now in its thirteenth year. RaDaR’s oldest recruiting site is Bristol Royal Hospital for Children (Bristol, UK), which started recruiting in 2010, and it now enrols patients from 108 renal units across all four nations of the UK. To date, RaDaR has recruited over 30,000 patients. It is the largest rare kidney disease registry in the world.

We have also received nearly 350 genetic reports for RaDaR patients with Alport Syndrome from Guy’s and St Thomas’ Genetic Laboratory (London, UK). The analysis team at RaDaR have been able to use these to identify the exact genetic change for each of these patients. These genetic results will help us understand how different types of genetic changes might affect how severe each person’s kidney disease may become. We are in the process of obtaining more reports from genetics laboratories at Great Ormond Street Hospital (London, UK) and Bristol.

How we can use RaDaR

We will be presenting the results from several research projects using enriched RaDaR data at UKKW:

• Centre-level variation in tolvaptan prescribing for autosomal dominant polycystic kidney disease (ADPKD) in the UK: This study looked at whether there were any differences in how tolvaptan, a

medication for ADPKD, was prescribed in different renal units across the UK.

• The RaDaR: cross-sectional analyses of 25,817 adults and children with rare kidney diseases in the UK: Here we describe important clinical and social characteristics of more than 25,000 patients living with rare kidney diseases in the UK. We identify differences in ethnicity and social deprivation between rare diseases, and between adults and children recruited to RaDaR.

• The clinical demographics and natural history of rare kidney diseases in the UK: A longitudinal descriptive analysis using data from the RaDaR: In this study we used largescale patient data from RaDaR to describe patterns and risks of kidney function decline, end-stage kidney disease (ESKD) and death for 20 rare kidney diseases.

• Proteinuria and its association with disease progression in IgA nephropathy: analysis of the UK national RaDaR IgA nephropathy cohort: This study, recently published in the Clinical Journal of the American Society of Nephrology (CJASN), used RaDaR data to describe relationships between proteinuria, rates of kidney function decline and lifetime risks of kidney failure for individuals with IgA nephropathy.

Katie Wong is a clinical research fellow at the University College London Department of Renal Medicine (London, UK)

The author stated no relevant disclosures.

2.0” projects evaluated in CX debate

Shahverdyan spoke next, offering an overview of the Velocity device (Venova Medical) from his point of view as a member of the scientific board advising on the product’s development. Its designers, he detailed, looked to build on the first generation of endoAVF devices by resolving their “reintervention and cannulation difficulties”. He explained that, unlike the ePath system, the Velocity is a single-catheter device that is guided by ultrasound only and without a sheath. It is used in the proximal radial artery, and the procedure utilises a 2.1cm long 4–5mm diameter tapered and fenestrated stent graft.

“When you deploy the implant and remove the catheter, you do not need to use external force for the anastomosis as in previous devices,” Shahverdyan stated. “You also cover the major branches during AVF creation, which otherwise steal the flow into the deep veins—this may help to achieve faster and better maturation rates of the superficial veins without losing flow into the deep veins. Hopefully, this will also reduce the risk of secondary interventions due to juxta-anastomotic issues.”

Animal studies produced “great results”, before first-in-human studies with a total of nine patients saw 100% procedural technical success, Shahverdyan said. The procedure should also be less painful than some alternatives as it can be performed under local anaesthesia.

Queried by Steiner on the unique advantages of these second-generation devices relative to earlier endoAVF technologies, Shahverdyan argued that, in the USA, the current rate of reinterventions with endoAVF is high. These fistulas frequently require balloon angioplasty and/or deep vein coil-embolization to assist maturation, and this is something which Shahverdyan envisions to be less of an issue with newer technologies.

existing devices. With both available systems, Shahverdyan averred, one of the exclusion criteria is the limited distance between the vessels at the anastomosis site. A stent graft would hence increase the number of suitable patients. With that in mind, he said, Venova Medical decided to broaden the length between the artery and the vein to 3mm in their VENOS 1 first-in-human trial. Asked where he saw the Velocity device fitting into his practice, Shahverdyan said that, if it lived up to its promise (high maturation and patency rates with low reintervention rates), it could be a complete replacement for both existing endoAVF devices.

Noting that Velocity uses stent graft and ePath offers them as an option, Steiner posed the question: “Will we see some of the issues we have seen with stents elsewhere—acute thrombosis, in-stent stenosis, edge stenosis?”

tend to feel less pressurised than typical sAVFs, probably due to the reduction of that turbulent flow. We anticipate similar haemodynamic changes. It is worth remembering that sAVF will still be there, and if endoAVF fails it will still be an option. It is an addition and not a direct replacement unless the results are significantly better for endoAVF.”

Hogan weighed in here to say it was flexibility around the site of fistula creation that was unique to the ePath system, enabled by the small size of the devices involved: “We can get down into some very small peripheral arterial and venous trees […] I think that should open up a broader range of patients that includes patients with vessels that are too far apart for either an Ellipsys or a WavelinQ procedure.” Preclinical trials in an animal model found even distances of 7–8mm were surmountable, he said, while adding as an aside that adjunctive procedures such as brachial vein embolisation can be done through the same access with which the device is inserted. These features both mark advances on the offering of first-generation devices.

Steiner stated in summary that, with second-generation systems, vessels could be further apart, resolving a limitation with both

Admitting he remained unsure, Shahverdyan said the initial trial in nine patients yielded only one early occlusion. Stent grafts, he suggested, benefitted from low resistance in the venous system to pull blood from the proximal or distal radial artery, leading to the implant remaining open for the longest six-week follow-up period recorded so far by the Velocity developers. “We will see in the future whether it comes to edge stenosis. If we achieve unassisted maturation of the target vein and can cannulate early, hence removing the dialysis catheters as soon as possible, that possible secondary hyperplasia would not be so relevant anymore.”

“Stent technology is moving on at great pace,” Hogan added. “In our case, the ePath allows us to deploy the stent that is most appropriate for a patient and their anatomy. We are not limited to one type or design of stent.”

Steiner suggested both devices create something that more closely resembles a surgical AVF (sAVF) than Ellipsys or WavelinQ. “But if it does,” she asked, “why not create an sAVF?”

“The idea of endoAVF is not only that it is minimally invasive now,” Shahverdyan answered, “but it is also that low flow into the superficial veins might keep them from aneurysm or stenosis—especially downstream cephalic arch stenosis. We think that with a tapered formation of the implant it almost mimics the VasQ (Laminate Medical) anastomotic external support device in that we have tapered laminar flow—VasQ AVFs

Hogan echoed this desire to preserve laminar flow by creating a gentler turn for the blood. This, he hopes, will limit flow issues. Steiner put it that, though it was a “very similar anatomical location [with ePath] to a sAVF, it was still a very different way of making the fistula” compared with a sAVF. Agreeing, Hogan said it was about “standing on the shoulders of giants, learning from previous endoAVF technologies as well as sAVF. It is about trying to combine the best of all of those approaches into one offering for patients and for clinicians.”

Asked to “put his business head on”, Hogan answered the issue of adoption and cost by saying that the upfront cost of endoAVF technology sometimes prevents clinicians from seeing the long-term cost benefit offered by their improved outcomes. Shahverdyan concurred, saying that fast procedures and good outcomes— and the avoidance of failed sAVF procedures— could save on costs in the long run.

Quizzed finally by Steiner on the prospects for their devices, Hogan said that, from a pivotal study and regulatory point of view, things would be “much clearer” in around a year. On Velocity, Shahverdyan said a multicentre pilot study was “hopefully planned” for autumn or winter 2023. Steiner stated simply: “Watch this space.”

“EndoAVF

Velocity system

(from left) Robert Shahverdyan, Simon Hogan and Kate Steiner discuss the future of endoAVF technology

“We can get down into some very small peripheral arterial and venous trees […] I think that should open up a broader range of patients that includes patients with vessels that are too far apart for either an Ellipsys or a WavelinQ procedure.”

Simon Hogan

ePath system

Point of View

Wei Li & Mareena Zachariah

A multidisciplinary IN fellowship training programme for a new paradigm in kidney care

Emerging in 1966 when pioneers Belding Hibbard Scribner, Stanley Shaldon, and Michael J Brescia broke ground in vascular access for haemodialysis,1 interventional nephrology (IN) has grown, evolved, and now expanded with a wide range of minimally invasive techniques to diagnose and treat kidney-related conditions. These include vascular access creation and maintenance, thrombectomy, embolisation, and stent placement, among others. IN has become an essential component of nephrology practice, where it offers patients with kidney disease a less invasive and more efficient way of managing their conditions.

Societies, including the American Society of Diagnostic and Interventional Nephrology (ASDIN), have helped to provide education and training for nephrologists interested in interventional techniques since the 2000s2, during which time the IN training has been led by interventional nephrologists, mainly in private practice settings. 3 There is a consensus that the future of IN will depend on the quantity and quality of its fellowship training programmes in tertiary medical centres, especially large academic medical institutions.1-5 However, as the demand for training in IN increases, IN programme directors may encounter several challenges—or even find themselves in the centre of “turf wars” in hospitals with sophisticated hierarchies and subspecialties, including endovascular and vascular surgery, and interventional radiology.

The first hurdle is patient-related factors. Patients with ESKD often have multiple other vascular comorbidities, which can increase their risk of intra-procedural complications that need immediate on-the-table surgical interventions. Another is that IN trainees need to be taught with a high level of technical expertise. There has been recent emphasis on ultrasound utilisation in IN,2,3 but unlike vascular surgeons interventional nephrologists are not currently required to possess Registered Physician in Vascular [ultrasound] Interpretation qualifications (RPVIs).

Interventional nephrologists may face challenges related to limited resources, such as access to standard operating room, specialised equipment, and imaging technologies with a hybrid setting where

open surgeries can be performed simultaneously with endovascular procedures. This can make it difficult for interventional nephrologists to perform complex haemodialysis access procedures and achieve optimal outcomes for patients.

There is also a lack of standardisation. ASDIN has developed multiple clinical practice guidelines, issued current IN fellowship accreditations, and aimed to receive Accreditation Council for Graduate Medical Education (ACGME) approval for subspecialty certification.2,3,5 However, current IN fellowship graduates have not been equally recognised as other ACGME accredited fellows by hospital credentialing committees, who may raise some possible liability concerns, where interventional nephrologists are not adequately and equally as trained to perform dialysis access procedures as the vascular surgeons are. This has been particularly noted in countries like the USA, where medical malpractice is a major burden on both hospitals and physicians.6,7

Building the programme

To address the above challenges, it is essential to think via an out-of-the box strategy and expand the scope of multidisciplinary care not only in patient care but also for training future interventional nephrologists. We propose, through a collaborative effort from multiple specialties, the unique venture of an endovascular and vascular surgeon-led IN fellowship training programme.

An endovascular and vascular surgeon-directed IN fellowship training programme can provide a range of advantages to trainees looking to pursue a career in the field of IN. A surgeon-led training programme can provide IN fellows with

comprehensive training, including a greater emphasis on surgical techniques as well as endovascular means of dialysis access while covering both vascular and nephrology dimensions. This can help IN trainees in becoming more skilled and confident in performing IN procedures, which can improve not only their knowledge and expertise but also their competency while bolstering their overall training experience. A vascular surgeonled programme may offer access to specialised equipment, resources, and facilities designed for complex vascular procedures. Hands-on experience with and exposure to the latest hybrid technology and techniques can enrich their skillset.

A vascular surgeon-led IN fellowship training programme can provide a more multidisciplinary approach to care, enabling collaboration among more surgical specialties to improve patient care. The existing broad scope of vascular surgery practice has an inherent power to facilitate this among nephrologists, vascular surgeons and interventional radiologists. By allowing vascular surgeons to lead an IN training programme, fellows may be better prepared for a variety of broader career opportunities. Furthermore, IN fellows graduating from a surgeon-led training programme have the advantage of the necessary credentials to perform certain surgical dialysis accesses, which may expand their scope of practice.

The winning strategy for such a training programme should include several key components to ensure success by focusing on providing a comprehensive and structured training programme that covers all aspects of IN. First among those is a set of clear goals and objectives. These goals should help them develop the necessary knowledge, skills, and abilities to become proficient in IN procedures, rather than just as a “surgeon and nephrologist”. The curriculum, meanwhile, should cover all aspects of IN and be updated regularly to incorporate new techniques, hands-on training, and opportunities for research and scholarly activities .

High quality of care should be a top priority. The programme should ensure that the fellows have a clear understanding of the importance of patient safety, ethical considerations, and informed

consent with close adherence on the current individualised and patient-centred Kidney Disease Outcomes Quality Initiative (KDOQI) guideline. 8 Through the lens of social determinants of health, the programme should also advocate a culture of continuous learning, safety and professionalism while emphasising ethical conduct when caring for underserved and vulnerable patient populations.

There are pitfalls to avoid with a surgeon-led IN programme. It is important to ensure that the programme—both faculty and trainees—is diverse and inclusive in race, gender, and ethnicity. Collaborations with training programmes from other specialties should be encouraged, as should the wise allocation of cases. That is especially important when the programme faculty members also serve on other training programmes, such as vascular surgery residency/fellowship programmes—it is vital to stay away from ACGME red tape.

There is a risk of inadequate support for fellows. Such support can include financial support, access to resources, and mentorship. Good communication is critical for a successful programme, too, with clear channels in place to ensure that all stakeholders are informed and involved. The programme should avoid inflexibility and be able to adapt to the changing needs of the fellows and the field of IN.

This can include incorporating new technologies and techniques as they become available. For example, the development of the endovascular arteriovenous fistula (endoAVF) has had a significant impact on the field of IN and vascular surgery, including IN and vascular surgery training programmes. An endovascular and vascular surgeon-led interventional nephrology fellowship offers a unique training module with a “one-stop shop approach”, meaning endovascular, possible surgical arteriovenous fistula (sAVF) creation through a single visit. In addition, with a surgical capability as back-up, certain complex and challenging end-stage renal disease access cases can be achieved safely and successfully with the new technology, when patients would otherwise have been left with only a life-long central venous catheter as a dialysis option.10

Overall, an endovascular and vascular surgeon-led IN fellowship training programme can provide significant advantages for IN trainees, including a comprehensive training curriculum and exposure to complex cases, as well as enhanced collaboration with vascular surgeons and other specialties’ providers. These will ultimately improve patient outcomes. Such a fellowship also offers trainees unique professional development experience that may prepare them with better credentialing opportunities for successful future career pathways in the field.

Wei Li (SUNY Upstate Medical University & Syracuse VA Medical Center, Syracuse, USA) is an endovascular and vascular surgeon and the founding programme director of a surgeon-led future IN fellowship programme.

Mareena Zachariah (Texas Tech University Health Sciences Center, Lubbock, USA) is a division chief and expert on transplant nephrology, onco-nephrology, and general nephrology.

References available online at renalinterventions.net

Disclosures: Wei Li disclosed that he is a consultant with Gore Medical and principal investigator on the CONNECT-AV trial from BD. Mareena Zachariah stated no relevant disclosures.

“A surgeon-led training programme can provide IN fellows with comprehensive training, including a greater emphasis on surgical techniques.”

Angioplastyassisted maturation effective even in

small veins

It has been suggested by some, such as Khalid Bashar (University Hospital Limerick, Limerick, Ireland) et al in the International Journal of Surgery in 2015, that cephalic veins smaller than 3mm in diameter used for arteriovenous fistulas (AVFs) are more prone to maturation failure than larger veins. Now, however, a new study in Hemodialysis International has suggested that balloon angioplasty for maturation assistance can be as effective in these smaller veins as in ones larger than 3mm.

THE STUDY AUTHORS, LED BY Tsung-Chi Kao (Chang Gung Memorial Hospital, Taoyuan City, Taiwan), emphasise the view that small-diameter veins are commonly “considered to have poor outcomes” for AVF maturation. It was with this in mind that they investigated the long-term patency outcomes of these veins in the context of angioplasty assistance.

For this study, Kao and colleagues devised a single-centre study including 61 patients, of whom 22 experienced full maturation of their AVF without extra intervention. The remaining 39 AVFs failed to mature, and 38 of these underwent a salvage balloon angioplasty procedure while one patient received peritoneal dialysis. From the 38, 36 achieved a functional AVF as a result of the assistance.

A Kaplan-Meier analysis “revealed no significant differences between the [unassisted] AVF and balloon-assisted maturation groups”, with primary functional patency for the former (p=0.503) proving similar to the latter (p=0.499). At one-year follow-up, primary functional patency in the angioplasty group was 94.7% compared with 93.1% in the unassisted maturation group. At three years, patency was 88.0% compared with 93.1% and at five years it was 79.2% compared with 88.3%. The authors did not find any significant difference in the duration of primary functional patency and assisted primary functional patency (p>0.05).

On a multivariate analysis, both the number of angioplasty procedures a patient underwent, as well as the diameter of the vein used, were found to be independent predictors of primary functional patency in both groups. A 1mm increase in the size of the vein was associated with a 0.13-fold probability of decreased patency duration (hazard ratio [HR]=0.13, 95% confidence interval [CI]: 0.02–0.99, p=0.049). Two balloon-assisted maturation procedures were associated with a 2.885-fold increased likelihood of decreased primary functional patency duration (HR=2.885, 95% CI: 1.09–7.63, p=0.033) compared with having only one such procedure.

Summarising the findings in their discussion, the authors state: “Balloon-assisted maturation is a relatively effective salvage management option with an acceptable long-term patency rate, even for small cephalic veins.”

Haemodialysis patients prefer comfort over longer life, study suggests

More patients undergoing maintenance haemodialysis for kidney disease have expressed a preference for a comfort-focused treatment over one that lengthens their life as much as possible in a new study published in JAMA Internal Medicine The findings suggest “important opportunities to improve the quality of care” of dialysis patients, say lead author Susan P Y Wong (University of Washington, Seattle, USA) and colleagues.

The style of care given to maintenance dialysis patients, Wong et al argue, can be particularly intensive compared even with patients suffering from other serious diseases. They are more likely to spend time in intensive care units, more likely to die in hospital and less likely to receive hospice care. There is evidence, however, that this is not in step with patient preferences, with a previous JAMA Internal Medicine-published study, also led by Wong, among several suggesting that treatment choices for end-of-life dialysis patients “are more strongly and consistently associated with system-level and healthcare professional–level factors than with individual patient characteristics”.

In this study, Wong et al took particular interest not only in whether patients preferred intensive or comfort-focused care, but also whether such a preference showed in how they perceived or prepared for end-of-life care. To that end, they designed a survey study that included questions on both “a range of aspects of end-of-life care” and “level of engagement in advance

Minimum staffing ratios fail to improve dialysis outcomes

A new study published in Hemodialysis International has found that minimum staffing regulations for haemodialysis facilities may not be associated with improved patient outcomes. Led by Allan Jacob (Physicians Dialysis, Miami, USA) and featuring corresponding author Edward Timmons (West Virginia University, Morgantown, USA), the authors have called for research on such regulations at the facility level.

JACOB AND COLLEAGUES SET OUT SOME CONTEXT for their research by noting that eight US states, as well as Washington, DC, have mandated regulations on staffing numbers in an attempt to improve dialysis treatment. For their study, they used data from the US Renal Data System to analyse the effects of a mandated minimum ratio between treatment staff and dialysis patients. They employed a synthetic difference-in-differences method of estimation to compare death and hospitalisations for patients with end-stage renal disease (ESRD) in centres with and without mandates.

“We were unable to find evidence that mandated dialysis staffing ratios are associated with a reduction in mortality or hospitalisations,” Jacob et al aver. They add that they estimate “a slight reduction in deaths per 1,000 patient hours” as well as a “slight

planning” among haemodialysis patients. The survey was completed in the period 2015–2018 by 1,006 patients from 31 non-profit and not-for-profit dialysis centres in the greater metropolitan areas of Seattle and Nashville, USA. The patients’ survey responses were then linked to their data in the United States Renal Data System (USRDS), with a final analytical cohort of 933.

Participating patients had a mean age of 62.6 years, while 525 (56.3%) were male and 254 (27.2%) were Black. In total, 452 (48.4%) stated they would prefer comfort-focused care, 179 (19.2%) that they would value longevity-focused care, and 302 (32.4%) that they were “unsure which of these they would prefer”.

However, these differences “did not translate into substantial differences in either engagement in advance care planning or end-of-life care.” A large proportion did not have a designated surrogate decision-maker (estimated probability, 47.5%; 95% confidence interval [CI] 42.9%–52.1%). There was not a significant difference in rates of discussion of hospice care or in discussion of stopping dialysis.

Reviewing the findings, the authors set out the challenge suggested by the results: “Advance care planning is a proactive process that aims to clarify patients’ values, goals, and preferences for future medical care to ensure that each individual receives care that is aligned with what is most important to them. Our findings speak to the obstacles to achieving this ideal and the important targets for intervention to improve advance care planning in this population.”

increase in hospitalisations” in response to their results, but that neither of these were found to be statistically significant effects.

The results echo the suggestions of previous analyses of data on minimum staffing ratios. In an editorial published in the Clinical Journal of the American Society of Nephrology (CJASN) in 2018, Anjay Rastogi (University of California Los Angeles, Los Angeles, USA) and Glenn M Chertow (Stanford University School of Medicine, Palo Alto, USA) made the case that “publicly available data from Dialysis Facility Compare and the ESKD Quality Incentive Program” demonstrated that “outcomes, including survival, rates of hospitalisation and infection, and patient satisfaction are not superior in states where mandated staffing ratios are in effect”.

Conversely, the Identifying Best Practices in Dialysis (IBPiD) study led by Brennan M R Spiegel (VA Greater Los Angeles Health System, Los Angeles, USA), the results of which were published in the American Journal of Kidney Disease (AJKD) in 2010, suggested access to additional staffing was associated with improved outcomes when facilities were compared by haemoglobin outcomes.

Jacob and colleagues state that their own findings “highlight the need for future work” to clarify the situation on staff mandates. They add that an analysis that examines results at the “facility level”, rather than more broadly, may elucidate their capacity to improve outcomes.

Speaking exclusively to Renal Interventions, Timmons said: “Our work provides evidence that minimum staffing ratios in haemodialysis clinics may not be serving their intended purpose of improving quality. Policy makers may wish to reconsider these mandates since they impose additional cost on dialysis facilities.”

Edward Timmons

Susan P Y Wong

Michael Casey & Derek DuBay

Multilevel intervention to improve racial equity in access to kidney transplant

Several studies report that African Americans are less likely to be added to the kidney transplant waitlist in the USA.1-3 A recent study reported that African Americans were surprisingly referred for kidney transplantation at a higher rate than Caucasians, but were less likely to initiate kidney transplant evaluation, complete kidney transplant evaluation, and be added to the waitlist.4 Thus, efforts need to focus on reducing barriers to initiating and completing an evaluation once referred for transplant.

At the Medical University of South Carolina, 65% of patients referred for kidney transplant self-identify as African American. We clearly recognised a disparity in African Americans not completing evaluations and being added to the waitlist compared to Caucasians. Therefore, our centre enacted a multilevel intervention to reduce structural barriers in trans-

Demographic reporting “essential” to cut renal trial racial disparities

Though Black patients are “wellrepresented” in nephrology trials in the USA, Asian patients are insufficiently represented in both US and international studies. That is the conclusion of a new study published in the Journal of the American Society of Nephrology (JASN). Its authors, led by Qandeel Soomro (NYU Langone Health, New York, USA), argue that under-representation risks “worsen[ing] disparities” in health outcomes between ethnic groups.

tan areas geographically distant from our transplant centre, allowing for improved communication and coordination with community nephrologists and dialysis centres. Finally, our centre adopted virtual social work, pharmacy, and dietary assessments to free up the in-person evaluation visit for physician assessment and key medical testing.

We used a modified version of the Kidney Transplant Equity Index (KTEI)7 to measure the impact of these interventions over time. KTEI was defined as the proportion of African Americans initiating evaluation, completing evaluation and waitlisting (numerator) divided by the proportion of African Americans in South Carolina receiving dialysis (denominator).

A KTEI=1 signifies equity and a KTEI<1 signifies disparity. From 2017 to 2021, KTEI trends significantly improved for initiated evaluations (KTEI 0.88 to 1.00), completed evaluations (KTEI 0.85 to 0.95), and waitlist additions (KTEI 0.83 to 0.96).5

plant waiting list. It is imperative that we, as a transplant community, create a more streamlined process to allow more underrepresented ESKD patients access to the waiting list and a life-saving transplant.

Michael Casey is a transplant nephrologist at the Medical University of South Carolina (Charleston, USA).

Derek DuBay is a transplant surgeon at the Medical University of South Carolina

References:

1. Saunders MR, Cagney KA, Ross LF, et al. Neighborhood poverty, racial composition and renal transplant waitlist. Am J Transplant 2010;10:1912–7.

2. Patzer RE, Amaral S, Wasse H, et al. Neighborhood poverty and racial disparities in kidney transplant waitlisting. J Am Soc Nephrol 2009;20:1333–40.

plant access in effort to close the racial disparity gap.5

The first intervention was reducing physician variability in the evaluation process via the development of a formal algorithm for medical and social work evaluation which was disseminated to all persons involved in the evaluation as a laminated card and made available on our centre’s intranet. Adherence to this algorithm eliminated extraneous testing and provided a consistent message to patients, referring providers, and dialysis centres. The second intervention (reported previously 6 ) involved dialysis centre-based transplant education designed to increase patient’s knowledge and self-efficacy with regards to their belief that they could complete a transplant workup. Another intervention utilised virtual evaluations to initiate kidney transplant evaluations and telehealth hubs based in metropoli-

This single-centre study suggests that the kidney transplant evaluation process is overly burdensome and reducing structural barriers during the referral and evaluation processes affords the opportunity for more African Americans to gain access to kidney transplantation. The net result of these interventions is a more streamlined evaluation process that is simpler for patients to navigate. The authors admit that there remain many opportunities to further refine the process.

The structural barriers addressed in these interventions were not originally developed with the goal of excluding certain patient populations from kidney transplantation. In fact, the (complex) kidney transplant evaluation process was created with the best of intentions, to provide a comprehensive medical and social assessment of the end-stage kidney disease patient (ESKD). There is a growing body of literature, however, that calls into question if some commonly-utilised medical tests used during the transplant evaluation process accurately risk stratify patients.8 Furthermore, there is increasing ethical scrutiny levelled against components of the social assessment.9

In the USA, there are roughly 500,000 ESKD patients on dialysis and only 20% of those are represented on the kidney trans-

MAKING THE CLAIM THAT THERE HAS NOT BEEN sufficient description previously of reporting and enrolment practices in randomised clinical trials (RCTs), particularly in regard to racial and ethnic minorities, Soomro et al set out to compile data from PubMed that would provide greater clarity. In their analysis, the authors retrieved data from “ten high-impact journals” for the period 2000–2021 from PubMed. Pilot trials and those with fewer than 50 participants were not included, while the outcomes of interest were designated as the proportion of trials reporting race and ethnicity as well as of number of participants enrolled “in each race and ethnicity category”.

In total, data from 380 trials were included from across the world. Soomro et al found that “just over half” reported race, while only 12% reported ethnicity. Though “most enrolled participants were White,” they note, “Black individuals accounted for ≤10% of participants except in dialysis trials where they accounted for 26% of subjects.” They also point out that Black patients’ enrolment rates were high “relative to disease population prevalence” in trials taking place in the USA that related to chronic kidney disease (CKD), dialysis and kidney transplantation.

3. Ng Y-H, Pankratz VS, Leyva Y, et al. Does racial disparity in kidney transplant wait-listing persist after accounting for social determinants of health? Transplantation 2020;104:1445–55.

4. Patzer RE, McPherson L, Wang Z, et al. Dialysis facility referral and start of evaluation for kidney transplantation among patients treated with dialysis in the Southeastern United States. Am J Transplant 2020;20:2113–25.

5. Taber DJ, Su Z, Gebregziabher M, et al. Multilevel Intervention to Improve Racial Equity in Access to Kidney Transplant. J Am Coll Surg 2023;236(4):721-7.

6. Morinelli TA, Taber DJ, Su Z, et al. A dialysis center educational video intervention increases patient self-efficacy and kidney transplant evaluations. Prog Transplant 2022;32:27–34.

7. Delman AM, Turner KM, Silski LS, et al. The Kidney Transplant Equity Index: improving racial and ethnic minority access to transplantation. Ann Surg 2022;276:420–9.

8. Cheng XS, Van Wagner LB, Costa SP, et al. Emerging Evidence on Coronary Heart Disease Screening in Kidney and Liver Transplantation Candidates: A Scientific Statement From the American Heart Association: Endorsed by the American Society of Transplantation. Circulation 2022;146:e299–e324.

9. Berry KN, Daniels N, Ladin K. Should Lack of Social Support Prevent Access to Organ Transplantation? Am J Bioeth. 2019;19(11):13-24. doi:10. 1080/15265161.2019.1665728

The authors stated no relevant disclosures.

There, they represented 19% for acute kidney injury (AKI) trials, 26% for CKD, 44% for glomerulonephritis, 40% for dialysis and 26% for transplantation trials. Hispanic patients, meanwhile, represented 13% of participants in US dialysis trials—though they make up 29% of the US dialysis population. The authors go on to describe global under-representation of Asian patients in nephrology trials, adding that there is “marked underrepresentation in US CKD, dialysis and transplants trials”.

Though they make the case that “Black and Hispanic patients are well-represented” in nephrology trials, Soomro and colleagues argue in reviewing the findings: “More complete recording of race and ethnicity in nephrology trials is needed […] Asian patients are poorly represented in kidney trials both globally and in the USA.”

Speaking on the study to Renal Interventions, Soomro stated: “Our systematic review highlights the crucial need for comprehensive reporting of the demographics of the study population and transparent enrolment processes. This is essential to translate the findings of the trial into clinical practice. All stakeholders must make concerted efforts to ensure reporting standards are met and the study population reflects the disease and population prevalence.”

Qandeel Soomro

Clinical and Industry News

AstraZeneca shares real-world data from REVOLUTIONIZE I study

AstraZeneca has presented data from the REVOLUTIONIZE I real-world evidence (RWE) study that show the recurrent nature of hyperkalaemia in patients with CKD and demonstrate the unmet need for these patients at the National Kidney Foundation (NKF) Spring Clinical Meeting (11–15 April, Austin, USA).

REVOLUTIONIZE I was a retrospective, observational, RWE study of US electronic health records that evaluated the recurrence of hyperkalaemia following a medical nutrition therapy (MNT) visit, also referred to as dietary counselling, in 2,048 adults with hyperkalaemia and Stage 3 or 4 CKD. Patients were followed up for six months post-MNT and were censored when they died or initiated outpatient potassium binder therapy. The study found that the percentage of patients with CKD stage 3/4 who had recurrent hyperkalaemia increased from one month (37.4%) to six months (56%).

When looking at the patient population from first hyperkalaemia recurrence (n=842) to the fourth hyperkalaemia recurrence (n=204), the average time between recurrences progressively decreased to less than 30 days over time (from 45 days to 27 days) and the percentage of patients with hyperkalaemia recurrence increased in those with a prior recurrence (from 56% to 70%) during the six-month follow-up post-MNT.

The RWE study, an AstraZeneca press release states, highlights an unmet need for an oral anti-hyperkalaemia therapy for treating patients with the condition.

Humacyte completes enrolment in Phase 3 trial of Human Acellular Vessel for vascular access

Humacyte, a clinical-stage biotechnology platform company developing universally implantable bioengineered human tissue at commercial scale, has announced that it has completed enrolment of a Phase 3 trial in haemodialysis access. The V007 trial is designed to assess the efficacy and safety of its Human Acellular Vessel (HAV) product in establishing vascular access for haemodialysis patients with end-stage renal disease (ESRD) as compared to autogenous arteriovenous fistulas (AVFs).

The trial is a prospective, multicentre, randomised, comparative study in 240 haemodialysis patients suffering from ESRD in the USA. Enrolled individuals were randomly assigned to either the HAV, or an AV fistula for haemodialysis. Efficacy assessments include usability of the conduit for dialysis at six and 12 months and a comparison of secondary patency, evaluated at 12 months. The rate of dialysis-related infections in both HAV and AVF subjects will also be tracked as a secondary endpoint.

“Completing enrolment in this Phase 3 trial brings us one step closer to our goal of providing vascular

access for dialysis patients that is usable more quickly after implant and reduces reliance on catheters, compared to AVF procedures,” said Shamik Parikh, chief medical officer at Humacyte. “We believe our regenerative medicine technology has the potential to transform the quality of care nephrologists are able to provide to their patients, and address the substantial failure rate and risk of infection associated with the current AV access options for haemodialysis.”

Xenotransplantation data presented on porcine donor kidneys

At the NKF Spring Clinical Meetings, researchers from Massachusetts General Hospital (Boston, USA) presented new data highlighting long-term outcomes for cynomolgus macaques transplanted with kidney xenografts from porcine donors harbouring genetic modifications as part of a new study.

In the study, kidney xenografts from porcine donors, modified to remove three major carbohydrate xenoantigens, called “triple knockout” (TKO) and express up to seven human transgenes, were evaluated in a nonhuman primate transplant model. The genetic modifications were intended to address cross-species molecular incompatibilities that lead to organ rejection, a major hurdle in the field of xenotransplantation. Xenografts from donors with TKO and human transgenes demonstrated prolonged survival compared to those with TKO alone, with one graft surviving over two years posttransplant.

“The two-year transplant survival outcome is a highly encouraging finding and represents a significant milestone for the xenotransplantation field,” said Toshihide Tomosugi, (Massachusetts General Hospital, Boston, USA). “This groundbreaking study brings us one step closer to clinical testing of a geneedited porcine renal graft in humans, potentially offering a much-needed approach to supply human compatible organs to alleviate the organ shortage and also providing an alternative therapeutic option for end-stage kidney disease (ESKD).”

MAGMA trial results suggest spironolactone effective for CKD

The main results of the Magnetic Resonance Imaging Evaluation of Mineralocorticoid Receptor Antagonism in Diabetic Atherosclerosis (MAGMA) trial, a National Heart, Lung, and Blood Institute (NHLBI)-sponsored trial were presented last month at the NKF Spring Clinical Meetings. Although the results of the trial are not final, they offer new information for patients using the generic drug spironolactone. The drug activates white cells and reduces tissue damage, and also reduces proteins that “would normally be considered inflammatory”, according to a press release. This may help limit chronic kidney disease (CKD).

“My message to patients is to

consider using spironolactone as their generic drug choice if they can for appropriate indications. We want to consider using this drug in high-risk patients with diabetes and atherosclerosis, because the benefit of the drug might extend not only to preventing kidney disease progression but potentially other benefits,” explained Sanjay Rajagopalan (Case Western Reserve University School of Medicine, Cleveland, USA). “Having a drug that works on these systems in a connective manner is a big benefit to a patient, and this drug happens to be one of those.”

A press release highlights details of the trial, including that 79 patients were randomised at 4 sites in the USA and Canada to spironolactone (n=37) vs placebo (n=42) for 12 months, after a two-week single-blind placebo lead-in period and four-week dose escalation phase. Mean age was 64±8 years; haemoglobin A1c (HbA1c) 7.3±1.3%; estimated glomerular filtration rate (eGFR) 44ml/min/1.73m2; baseline systolic blood pressure 132 ±19mmHg.

New data presented on IceCure cryoablation system for tumour treatment

IceCure, developer of the minimallyinvasive cryoablation ProSense System which has shown promise in the treatment of renal masses, has announced that it has been used in a single-site study conducted at the Sorbonne University Department of Interventional Radiology and Oncology, Tenon Hospital in Paris, France by lead investigator Francois H Cornelis, (Memorial Sloan Kettering Cancer Center, New York, USA) and a team of doctors.

on chronic maintenance dialysis. The approval is applicable to all 27 European Union member states plus Iceland, Norway and Liechtenstein. Vadadustat is now approved in 32 countries.

“We are extremely pleased the EC has approved Vafseo, an important milestone for Akebia, but even more impactful for the hundreds of thousands of Europeans diagnosed with anaemia associated with CKD on dialysis,” said John P Butler, chief executive officer of Akebia. “We believe patients receiving chronic maintenance dialysis would benefit from additional therapeutic options. With approval, we are eager to select a European partner who can quickly bring Vafseo to those patients.”

Anaemia associated with CKD, common in patients on dialysis, is a debilitating condition which may be associated with many adverse clinical outcomes. Vafseo, approved in 150mg, 300mg and 450mg film-coated tablets, provides a once-daily oral treatment option for dialysis dependent patients with symptomatic anaemia associated with CKD. Throughout Europe, more than 200,000 dialysis patients are currently treated for anaemia associated with CKD.

Xeltis presents six-month first-in-human data on aXess graft

Xeltis has presented “highlyencouraging” six-month data from its first-in-human (FIH) aXess vascular graft trial at the 13th Congress of the Vascular Access Society (VAS; 27–29 April, Porto, Portugal).

The study, titled “Pain-free survival after percutaneous image-guided cryoablation of extraperitoneal endometriosis” was published in the Journal of Vascular and Interventional Radiology (JVIR). The independent study and published paper were not sponsored by IceCure. Cornelis presented the study data at the Society of Interventional Radiology 2023 Annual Scientific Meeting (4–9 March, Phoenix, USA). The study concluded that percutaneous cryoablation is a safe and effective procedure that significantly reduces pain and obtains local control of experitoneal endometriosis. The median follow-up was 13.5 months after cryoablation.

Anaemia drug Vafseo approved for treatment of dialysis patients

Akebia Therapeutics has announced that the European Commission (EC) has granted marketing authorisation for Vafseo (vadadustat), an oral hypoxiainducible factor prolyl hydroxylase (HIF-PH) inhibitor for the treatment of symptomatic anaemia associated with chronic kidney disease (CKD) in adults

A press release outlines that sixmonth data from the FIH trial found that the aXess vascular access graft for haemodialysis demonstrated high patency rates (80% primary patency, 95% primary assisted patency, 100% secondary patency). At six months, a 0% infection rate and low re-intervention rates were reported, resulting in a highly favourable safety profile. Haemodialysis was successfully performed through the graft, and compared to current standard of care measures, which typically show lower rates of patency combined with a greater risk of infection or rejection, aXess demonstrated “extremely promising” results.

Tozzi, who is principal investigator in Xeltis’ FIH clinical trial, said: “These six-month data are very promising in terms of patency and infection rates and suggest that aXess has great potential to be a game-changing alternative to existing vascular access options, which have a number of significant shortcomings. Xeltis’ vascular access implants, which harness the power of the body’s natural healing processes, could play a vital part in significantly improving the lives of patients requiring haemodialysis.”

The aXess FIH trial is a single-arm, non-randomised FIH feasibility study in Europe evaluating the preliminary safety and performance of the aXess graft in subjects who are older than 18 years with end-stage renal disease, and who are deemed unsuitable for fistula creation. Follow-up visits were conducted at regular intervals after initial procedure, with full study followup visits to be conducted at five years. The aXess pivotal trial is currently enrolling up to 110 patients across up to 25 sites in nine EU countries.

IceCure cryoablation system

Clinical and Industry News

South Korea) has engineered an artificial kidney that allows for the early detection of adverse drug reactions.

Smartphone CKD test wins digital health innovation award

Juniper Research’s Future Digital Awards 2023 has announced Healthy.io as the platinum winner for ‘Best Digital Diagnostics Solution’ in the Digital Health Innovation category for its Minuteful Kidney test.

The Minuteful Kidney test kit allows for early detection of chronic kidney disease (CKD) by enabling patients to take a clinical-grade, albumin-tocreatinine ratio (ACR) test in their own homes using a smartphone camera. The test kit is delivered directly to a patient’s front door and, at their own convenience, the Minuteful Kidney app walks them step-by-step through the test. Advanced colour vision and machine learning technology then read the image, translate it to a clinical-grade result, and inform the patient—and their doctor—about their kidney function.

The ACR test is a simple urine test that looks for albumin in urine, which can be a leading indicator for CKD. The Minuteful Kidney test is the first and only FDAcleared, smartphone-powered, at-home kidney test. The test uses smartphones to “break down barriers to care, such as high costs and transportation”, which is “important considering CKD’s symptoms do not surface until the late stages of the disease”.

Renalytix announces publication of real-world evidence on KidneyIntelX risk assessment test

Renalytix has announced the release of new real-world evidence case studies published in the peer reviewed journal Diabetic Nephropathy entitled: “The Need for Risk Stratification in Type 2 Diabetes and Chronic Kidney Disease: Proposed Clinical Value of KidneyIntelX”. The publication “underscores the importance of enabling early risk assessment in diabetic kidney disease to reduce likelihood of progression to kidney failure and dialysis”, according to a Renalytix press release.

The release lists a set of “key themes” emerging from the company’s “multidisciplinary clinical advisory panel” using KidneyIntelX. Among them are the claim that a lack of kidney disease education and patient awareness in the primary care setting is “a real barrier to care management”. A significant opportunity exists, the press release states, for type 2 diabetic patients to learn about chronic kidney disease

(CKD) management to improve health behaviour and medication compliance. It adds that a lack of risk assessment tools in primary care can prohibit identification of patients at high risk for kidney disease progression in early stages of the disease, and that primary care represents a “key point of contact for the entire diabetic kidney disease population”.

Furthermore, the press release argues, guideline recommendations to mitigate kidney disease effects in diabetes patients “are not optimally followed in routine clinical treatment”, and it suggests that earlier specialist referral of higher-risk diabetic kidney disease patients can mitigate patient overload in nephrology.

Handheld ECG device scoops CX 2023 Innovation Showcase prize

Judges of the CX 2023 Dragon’s Denstyle contest—the finale of the Charing Cross (CX) Symposium (25–27 April, London, UK) Innovation Showcase programme—described the field of entrants to this year’s edition of the competition as the strongest line-up in its history.

The judging panel of physicianinnovators selected HeartEye, a Netherlands-based developer of handheld electrocardiogram (ECG) devices, as the overall winner of the innovation prize, which comes with a £1,000 award. Honourable mention was given to four other entrants from the field of 12.

Peter Doevendans (UMC Utrecht, Utrecht, The Netherlands) gave an overview of the HeartEye technology in a short presentation entitled ‘ECG anytime, anywhere in 60 seconds’, describing it as a “digital transformation” for ECG acquisition. HeartEye is a pocket-sized device that can take clinical-standard ECG readings wirelessly, negating the need for a large, stationary ECG unit.

The technology, which has been developed with the support of an Innovative Medical Devices Initiative (IMDI) grant from the Netherlands Organisation for Health Research and Development (ZonMw) is patented, and could be marketed to healthcare providers or direct to consumers within two years, Doevendans explained.

“We have been doing this for a number of years, and this was the toughest by far,” said judging panellist Robert Mitchell (Park City, USA), before the announcement of HeartEye as the winner of the prize.

Artificial kidney for early detection of drug toxicity developed

The kidney plays a vital role in maintaining homeostasis within the body by eliminating toxic and superfluous substances in the bloodstream, including waste generated during metabolic processes, through urine. Nevertheless, toxicity can also be induced in the kidney from certain medications. Recently, a research team from Pohang University of Science and Technology (POSTECH; Pohang,

The POSTECH research team led by Dong-Woo Cho and Jinah Jang (POSTECH, Pohang, South Korea) fabricated a glomerular microvesselon-a-chip, which includes glomerular endothelial cells, podocyte layers, and a glomerular basement membrane (GBM) using a single-step fabrication process. The research findings have been published in the journal Biofabrication

“We have successfully replicated glomerular units of the kidney, which offer boundless potential for drug screening and nephrotoxicity testing in clinical practice,” explained Dong-Woo Cho, who led the study. He added: “This development will enable us to detect drug toxicity early by facilitating glomerulus disease modelling and to provide personalised treatment for patients.”

Percutaneous treatment better than ureteroscopy for kidney stones, study finds For patients with kidney stones measuring 1–2cm, a technique called mini-percutaneous nephrolithotomy (mini-PCNL) provides a higher stone elimination rate than another ureteroscopy, concludes a randomised trial in The Journal of Urology

“In our clinical trial, mini-PCNL was more likely to achieve stone-free outcomes, compared to ureteroscopy,” comments senior author Jorge GutierrezAceves (Cleveland Clinic, Cleveland, USA). “In patients with intermediatesized kidney stones, mini-PCNL may offer a more effective procedure, with similar safety and cost impact.”

Mini-PCNL is carried out through a small incision in the patient’s side. Previous studies comparing the outcomes of URS and mini-PCNL have had “important limitations”, a press release states. In the new study, 101 patients with 1–2cm kidney stones were randomly assigned to treatment with URS or mini-PCNL. All patients had a single intermediate-sized stone in one kidney. In both procedures, once the surgeon visualised the stone through instruments placed into the kidney, the stone was fragmented using a laser and removed using a basket device.

The study provides new information for the “nuanced” decision-making process for treatment of kidney stones measuring 1–2cm. The research authors state that their study is the largest North American randomised trial to directly compare mini-PCNL versus ureteroscopy for this group of patients.

New algorithm promises to predict diabetic kidney disease

Researchers from Sanford Burnham Prebys Medical Discovery Institute (La Jolla, California) and the Chinese University of Hong Kong (Hong Kong) have developed a computational approach to predict whether a person with type 2 diabetes will develop kidney disease. Their results are published in Nature Communications. The new

algorithm depends on measurements of DNA methylation, which a press release notes “can be easily measured through blood tests”.

“This study provides a glimpse into the powerful future of predictive diagnostics,” says co-senior author Kevin Yip (Sanford Burnham Prebys Medical Discovery Institute). “Our team has demonstrated that by combining clinical data with cutting-edge technology, it’s possible to develop computational models to help clinicians optimise the treatment of type 2 diabetes to prevent kidney disease.”

“There has been significant progress developing treatments for kidney disease in people with diabetes,” says co-senior author Ronald Ma (Chinese University of Hong Kong).

“Our computational model can use methylation markers from a blood sample to predict both current kidney function and how the kidneys will function years in the future, which means it could be easily implemented alongside current methods for evaluating a patient’s risk for kidney disease,” says Yip.

MediBeacon appoints new chief medical officer

MediBeacon has announced the appointment of a new chief medical officer, Steve Miller. A company press release details that Miller formerly served as executive vice president and chief clinical officer at Cigna, and has also been vice president and chief medical officer at Barnes-Jewish Hospital, Washington University School of Medicine in St Louis, USA. He has been a member of the MediBeacon board of directors since 2015.

MediBeacon is a medical technology company that, the press release states, is focused on advancing fluorescent technology to help improve patient care through the science of tracer agents and transdermal measurement.

“We are thrilled to have Miller take on a more active role at MediBeacon,” said Steve Hanley, chief executive officer, MediBeacon. “He has a strong understanding of the MediBeacon kidney monitoring technology as it applies to a range of unmet medical needs.”

“Understanding kidney function remains a significant clinical challenge,” said Miller. “Real-time, accurate renal function measurements have the potential to have meaningful impact in patient management. MediBeacon’s goal continues to be to provide technology to aid in both improving health outcomes and reducing costs of kidney disease.”

The MediBeacon Transdermal GFR Measurement System (TGFR) is designed to measure glomerular filtration rate (GFR), an indicator of kidney function, in real-time without the need for blood sampling or urine collection. The TGFR was given breakthrough device designation by the US Food and Drug Administration (FDA) and an Innovative Medical Device designation by the Chinese National Medical Products Administration (NMPA).

Currently underway is the MediBeacon TGFR Pivotal Study, which is a Phase 3 open label, multicentre, safety and pharmacokinetic study of Lumitrace (relmapirazin) and the use of the MediBeacon TGFR in normal and renal compromised subjects for the evaluation of kidney function.

Ronald Ma Kevin Yip

Healthy.io Minuteful Kidney test kit

Conference Calendar

05–07 June

UK Kidney Week (UKKW) Newport, UK ukkw.org

06–09 June

Leipzig Interventional Course (LINC) Leipzig, Germany leipzig-interventional-course.com

14–17 June

Society for Vascular Surgery (SVS)

Vascular Annual Meeting (VAM23) National Harbor, USA vascular.org/vam-2023

15–18 June

60th European Renal Association (ERA) Congress Milan, Italy era-online.org/en/milan2023

23–24 June

Endo Vascular Access (EVA) Meeting Patras, Greece evameeting.org

08–09 September

5th Hamburg Dialysis Access Symposium Hamburg, Germany asklepios.com/hamburg/barmbek/aerzte/ fortbildung/shunt-symposium/

Meet our editorial board

Ziv Haskal is a professor of radiology, and an interventional radiologist and interventional oncologist, at the University of Virginia School of Medicine in Charlottesville, USA.

09–13 September

Cardiovascular and Interventional Radiological Society of Europe (CIRSE) Annual Congress

Copenhagen, Denmark cirsecongress.cirse.org/about/promo-material/

17–20 September

European Society for Organ Transplantation (ESOT) Congress

Athens, Greece esot.org/esot-events/esot-congress-2023/

17–20 September

Vascular Access Society of Britain and Ireland (VASBI) Annual Scientific Meeting

Birmingham, UK vasbi.org.uk/vasbi-2023

Nicholas Inston Chairman of the Editorial Board

Nicholas Inston is a transplant and vascular access surgeon, and the clinical service lead for renal surgery, at Queen Elizabeth Hospital in Birmingham, UK.

Ziv Haskal Board Member

Stephen Hohmann Board Member

Stephen Hohmann is a vascular and general surgeon at the Texas Vascular Associates clinic in Dallas, USA.

Robert Jones Board Member

Robert Jones is an interventional radiologist at Queen Elizabeth Hospital in Birmingham, UK.