November 2020 | Educational Supplement
DCB in dialysis access
Do we finally have the right evidence?
vascularnews.com
This educational supplement has been sponsored by Medtronic
Treatment algorithm
Maintenance of arteriovenous dialysis access: My treatment algorithm Tobias Steinke talks through his treatment algorithm for the maintenance of arteriovenous dialysis access. AN ADEQUATE FUNCTIONING suggested the persistent effect of vascular access is the key factor the local paclitaxel application. for successful haemodialysis Target lesion primary patency was treatment. Guidelines advise the 86.1% at six months (standard creation and use of autologous PTA 68.9%). The access circuit arteriovenous fistulae (AVFs) primary patency at 6 months for haemodialysis, because of after using an IN.PACT drugbetter long-term patency and a Tobias Steinke coated balloon (DCB) was 73.2% lower incidence of complications. (112/153) in comparison to 48.0% Morbidity and mortality in haemodialysis (71/148) by standard PTA. Furthermore, the patients with AVFs is lower than in number of interventions required to maintain patients with grafts (AVG) or central vein target lesion patency through 210 days was catheters. The number of elderly patients on reduced by 56%. Results of the standard haemodialysis with multiple comorbidities, PTA arm were also impressive, highlighting poor vessel quality, previous vein punctures, the importance of vessel preparation and and earlier intravenous treatment are prolonged inflation time. This was already growing, making a successful creation and demonstrated by Panagiotis M Kitrou (Patras, providing a long-term patency of autologous Greece) in a subgroup analysis of the results AVFs in those patients more difficult. of a DCB Global Registry, presented at the The main cause of AVF or AVG 2019 Charing Cross Symposium (CX; 15–18 dysfunction is the development of stenoses April, London, UK), in which patients who that lead to reduced blood flow, which may reduce the efficacy of haemodialysis. If untreated, stenoses could progress and lead to thrombosis and loss of the access circuit. The standard of care for stenoses has been considered to be percutaneous transluminal angioplasty (PTA) alone; however, keep in mind that long-term patency is limited, and reinterventions to maintain patency are common. So, the main goal is to slow down the process of restenosis and to achieve a longer intervention-free period for did not undergo vessel preparation with haemodialysis patients. This was realised a high-pressure balloon had significantly over the last years by using drug-coated inferior patency rates compared with those balloons in AV-access. in which initial balloon angioplasty was A milestone was the data presentation performed. of the prospective, global, multicentre, When using a DCB, the avoidance of randomised IN.PACT AV Access trial in “geographic mismatch”, a prolonged inflation 2019 at the meeting of the Cardiovascular time, a greater DCB balloon diameter than and Interventional Radiological Society the standard PTA balloon (regularly 1mm), of Europe annual meeting (CIRSE; 7–11 and adequate inflation pressure are important September, Barcelona, Spain) showing to achieve superior results. A DCB is used encouraging results and delivering level to minimise the destructive effect of balloon 1 evidence. In this study, the increasing angioplasty due to vessel wall trauma. divergence of the curves showing primary Therefore the length of the DCB should patency and access circuit patency over be longer than the pre-dilatation injury, time was particularly convincing because it extending 5–10mm proximally and distally,
My strategy in treating AVaccess stenosis focuses on vessel preparation.”
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to ensure full coverage of the area. A DCB inflation time of more than three minutes was used in the IN.PACT trial with excellent results. To optimise balloon apposition to the lesion, and for the transmission of the drug into the vascular wall, a pressure higher than the nominal could be applied. Still, the current available meta-analysis carried out by Sean A Kennedy (Toronto, Canada) had limitations. Mostly patients with AVF were presented in the available literature; only a few studies investigated the use of DCB in patients with AVG. Further studies are needed, particularly for AVG and central stenosis, to raise the level of evidence. So the IN.PACT AV Access trial—a prospective, global, multicentre, 1:1 randomised, single-blinded study—adds most valuable data right now. Elastic recoil is another challenge. Dheeraj K Rajan (Toronto, Canada) proved that elastic recoil is quite common in vascular access; this may require a mechanical scaffold for its treatment. Situations with elastic recoil in AVF/AVG stenoses cannot be addressed by a DCB. Therefore, the approach of a “nothing left behind” strategy must be modified in those patients. Although not indicated for use, bare-metal stents (BMSs) have been used to treat AVF/AVG stenoses, despite the inconsistent results in observational studies, absence of randomised controlled trials, and the well-known high rate of restenosis. To overcome limitations associated with PTA and BMSs, stent grafts are a strong option to inhibit restenosis and re-establish a functional AV access. In summary, my personal strategy in treating AV-access stenosis focuses on vessel preparation by pre-dilating the lesion with a high pressure PTA balloon. The nominal balloon diameter should match the inner diameter of the reference vessel distal to the target lesion, measured prior to the intervention by ultrasound. Followed by a DCB if pre-dilatation was successful, balloon diameter here should be greater than the standard PTA and fully cover and extend beyond the lesion length for about 5–10mm, with complete wall apposition essential. In case of recoil or flow-limiting dissection post-dilatation, prolonged and repeat inflations might be useful to optimise lesion dilatation. If this remains unsuccessful, stent grafts are an option to inhibit restenosis and re-establish a functional AV access. Tobias Steinke is head of the vascular surgery department at the Schoen Clinic Düsseldorf in Düsseldorf, Germany. References for this article can be found on www.vascularnews.com
November 2020
Pathophysiology
IN.PACT AV Access
Pathophysiology of dialysis access restenosis: Why early treatment is better Matteo Tozzi discusses the pathophysiology of dialysis access restenosis and explains why early treatment is better.
FROM 1996 TO TODAY, THE INTIMAL hyperplasia still represents the Achilles heel of vascular access, and is the most frequent cause of non-maturation or loss of native or prosthetic access. The two main causes of failure of native access are an inability to mature and subsequent venous stenosis. The exact pathology that causes a primary dysfunction of these fistulas is unclear. The pathology of peri-anastomotic venous stenosis in native fistulas is believed to be similar to outflow stenosis in prosthetic vascular accesses. It has been shown that intimal hyperplasia is composed of smooth muscle cells with expression of cytokines and inflammatory mediators such as endothelin, PDGF and TGF-Beta, and various degrees of mitotic index. The architecture of the neointimal lesion is complex and can present microvessels and inflammatory infiltrates in the luminal side and adventitial neoangiogenesis with perivascular fibrosis. Cellular infiltration takes place from the adventitia to the inner part of the vascular wall. The greater presence of macrophages represents one of the most evident differences in the cell population of prosthetic stenoses. The evolution of the stenosis is well known; the progressive luminal obstruction
Figure 1. Section of intimal hyperplasia and structure
Figure 2. De novo lesion. The intimal hyperplasia that determines the stenosis inside the venous vessel is clearly evident.
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causes the thrombosis of vascular access. Angioplasty is the current standard of care in the treatment of stenosis due to intimal hyperplasia in vascular access. But the complexity of the pathophysiology of Matteo Tozzi intimal hyperplasia in vascular access immediately showed the failure of the procedure; in fact, restenosis at regular time intervals is evidence. The mechanical activity of percutaneous angioplasty alone is not sufficient in the treatment. But considering the genesis of stenosis (migration, replication, and collagen production by a prevalent SMC [smooth muscle cells] cellular histotype), the combination of an antiproliferative drug, paclitaxel, to the angioplasty balloon (rendering it a drug-coated balloon; DCB), represents the ideal application. Since the first comparative studies between DCB and angioplasty alone, the combined treatment has shown a significant increase in the time interval between restenosis. There are still many doubts associated with DCB treatment of stenoses of vascular access. But the new randomised studies on the use of DCBs has created incontrovertible evidence: DCB use is the first choice treatment for stenoses caused by vascular access, with statistically significant results, especially in de novo lesions. The stenosis produced by intimal hyperplasia involves an increase in the proliferative index of SMC with a progressive increase in the cell population responsible for matrix production, one of the fundamental structural components of the stenosis. The proliferative index is increased by numerous factors, such as the uremic inflammatory stimulus, the haemodynamics of vascular access, and the parietal damage produced by angioplasty. This last factor is particularly evident in the stenoses that present early restenosis in which the hedge between intima and media of the vessel wall are completely subverted by the infiltration of the SMC and the abundant matrix. The evolution of the stenosis involves an increase
of the matrix at the expense of the active cell population up to a fibrosis of the vascular wall. Although there are many variables and differences between the different types of stenotic lesions, also from the morphological aspect of the stenostic vascular segment, the most significant clinical results of angioplasty with DCB in the de novo lesions are explained by physiopathology of intimal hyperplasia. Elevated proliferative index of the SMC and low degree of fibrosis of the wall are the characteristics of the early
From 1996 to today, the intimal hyperplasia still represents the Achilles’ heel of vascular access.” stenosis. The early inhibition of the cell population with a greater proliferative index, the SMC, therefore represents the ideal application of DCBs. Matteo Tozzi is an associate professor in the Department of Medicine and Surgery at the University of Insubria in Varese, Italy.
Bibliography 1. Portugaller RH, Kalmar PI, Deutschmann H. The eternal tale of dialysis access vessels and restenosis: are drugeluting balloons the solution? J Vasc Access. 2014 NovDec;15(6):439–47. 2. Castier Y, Lehoux S, Hu Y, Foteinos G, Tedgui A, Xu Q. Characterization of neointima lesions associated with arteriovenous fistulas in a mouse model. Kidney Int. 2006 Jul;70(2):315–20. 3. Lemson MS, Daemen MJ, Kitslaar PJ, Tordoir JH. A new animal model to study intimal hyperplasia in arteriovenous fistulas. J Surg Res. 1999 Jul;85(1):51–8. 4. Chang CJ, Ko PJ, Hsu LA, Ko YS, Ko YL, Chen CF, Huang CC, Hsu TS, Lee YS, Pang JH. Highly increased cell proliferation activity in the restenotic hemodialysis vascular access after percutaneous transluminal angioplasty: implication in prevention of restenosis. Am J Kidney Dis. 2004 Jan;43(1):74–84. 5. Tozzi M, Franchin M, Angrisano A, Tadiello M, Gattuso A, Castelli P. Histological evaluation of prosthetic vascular access: early cannulation vs. standard ePTFE. Vascular Access for Hemodialysis Symposium, May 12-14, 2016 Chicago, USA.
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Case-based report
My typical AV access maintenance case: A step by step case-based report In this case-based report, Alexandros Mallios talks through a typical AV access maintenance case. NATIVE ARTERIOVENOUS FISTULAE (AVF) are undoubtedly the best vascular access for end stage renal disease (ESRD) patients. Increasing numbers of the aging population and changes of epidemiology, increased prevalence of vascular disease, hypertension, and diabetes have made vascular access and AVF maintenance— previously considered an “exile child” for a few passionate physicians—a hot topic for health care practitioners, industry and even the government.1–3 Being a vascular surgeon who would normally do all types of vascular interventions, I find myself overwhelmed with referrals of patients with access problems, often inadequately treated for a period of time, because few centres truly know how to deal with complex access maintenance problems, and even fewer physicians take the time to deal with these problems appropriately and provide longlasting solutions. My assessment always starts with a fast but full clinical assessment of the problem. Is there a thrill or is the AVF pulsatile? In the case of a pulsatile fistula, this indicates a draining vein stenosis; then I will follow the trajectory of the vessel until I detect a transition from pulse to strong thrill and then a soft fistula. The location of the strong thrill indicates the stenosis with almost absolute accuracy, allowing one to rapidly and efficiently target the balloon dilatation under fluoroscopy or, in our case, most of the time under ultrasound guidance. In cases of brachial artery inflow or distal AVF, especially in young patients with very strong thrill and pulsatile AVF, coexistence of high flow with a relative “functional stenosis” needs to be considered. For example, a moderate stenosis of the cephalic arch with patent lumen of 4–5mm that is repeatedly ballooned and finally stented may be a “stenosis” for a 1600ml/min flow AVF that will present as a pulsatile fistula. However, if the flow is reduced to 700ml, the clinical presentation will change to a soft fistula with a satisfactory thrill and adequate flow for dialysis. Soft thrill or absence of thrill with
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high recirculation rates, poor arterial pressures, and quality of dialysis often indicate an inflow problem, which may be a Alexandros Mallios post-anastomotic, anastomotic, or arterial stenosis – with the latter being common in elderly diabetic patients. In not so rare occasions, patients present with a soft pulse in the AVF, and this indicates a double problem of inflow and outflow. Clinical examination should always be completed with ultrasound evaluation; scanning the patient at the outpatient clinic will allow accurate planning of the intervention, and this plan is noted as a reminder on the patient’s chart, which
the angle of the anastomosis is too sharp, it may also be difficult to cross with the wire or get enough support to cross with the balloon. Retrograde access of the distal radial artery access, with a 5Fr sheath, is an excellent choice for inflow problems, and allows the utilisation of up to 6mm balloons that should be the maximum diameter for this type of AVF stenoses. Lesions located in any segment of the artery, anastomosis, or post-anastomotic segment can be treated, and haemostasis is easily achieved with an inflatable bracelet, allowing for a safe and rapid procedure.4 Balloon choice is usually done based on the size of the vein and location of lesions. Regular compliant balloons can be used, but it is better to choose the ones with high rated burst pressure. Often, high pressure non-compliant balloons are needed, as these lesions may be hard to open due to significant fibrosis. Long time inflation and adequate mechanical treatment of the lesion is key to success. We generally tend to avoid stent placement with very rare exceptions of significant recoil. Application of drugcoated balloons may reduce patient suffering and access related morbidity, which will eventually translate to better patient care and reduced costs for healthcare systems.
Few centres truly know how to deal with complex access maintenance problems.” will allow appropriate installation of the patient and selection of material (C-arm vs. ultrasound, type of sheaths and balloons, location of puncture or punctures). In cases of outflow problems, puncture of the AVF is performed with a 7Fr (most often, 7Fr is adequate, unless central vein is treated, and a large stent needs to be placed) sheath at the site, which will allow easy access of the stenosis. In particularly tortuous or aneurysmal AVF, accessing the AVF too far from the stenosis may lead to undue difficulties accessing the lesion. When an inflow issue is suspected, a retrograde AVF puncture can be applied. It is generally easier and safer. However, it may prove challenging to inject contrast against the flow of the AVF. Injecting while compressing the AVF outflow, or crossing with a catheter and injecting from the artery, can provide a solution. In distal AVF, when
Alexandros Mallios is director of Vascular Access, Paris St Joseph and Chief of Vascular CH Chartres, Paris, France.
References 1. https://www.managedhealthcareexecutive.com/industryanalysis/what-trumps-kidney-executive-order-meanshealthcare 2. https://www.hhs.gov/about/news/2019/07/10/hhs-launchespresident-trump-advancing-american-kidney-health-initiative. html 3. https://www.cnbc.com/2019/07/10/kidney-dialysis-stockssoar-as-investors-cheer-trump-executive-order.html 4. https://vascupedia.com/presentation/clinical-decisionmaking-in-av-fistula-maintenance-step-by-step-salvageprocedure/
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Resources
IN.PACT AV Access
Vascupedia AV access resources Stenosis after arteriovenous (AV) fistula is frequent and often results in multiple reinterventions or fistula thrombosis. Treatment requires not only technical skills but also knowledge of the restenosis mechanisms and experience in the decision-making. However, Giovanni Torsello argues that the main challenge is to identify who will play a mentoring role in the single practice and how the operators can get updated information to appropriately treat the patient.
The traditional way of training and education
The traditional way of education by means of participating at several conferences, visiting the company’s booth, reading scientific articles, asking face-to-face questions to the experts and building a network with other physicians during the coffee breaks of the symposium seems to be unable to cover the need of physicians around the globe. Why? Because this kind of education became expensive, time-consuming and less compatible to the new way of searching for information: ‘I have a very specific question and I want a very specific answer…now’.
E-learning as a complementary educational tool
Based on the feedback of other specialties, the introduction of e-learning as a complementary educational tool seems to fill nicely this gap. The visit to the booth is now replaced by online animations of the product, the live presentations are replaced by recorded online presentations, the voting by raising the hand is replaced through a dedicated app, the networking in the coffee breaks is replaced by chatting in the social media. Interestingly, the 5,000-words paper of a scientific journal is now shortened to a virtual abstract with the key messages of the study. Of note, all this body of information is global, easily accessible and available 24/7.
The current status of e-learning in vascular medicine In vascular medicine, e-learning has been supported by several societies as an additional educational tool. The main challenges were the differing degrees of enthusiasm among the members of
the society, the lower priority upload content or comment compared to the annual meetings, on it. The platform consists of the high costs of web design, three different virtual rooms: the and most importantly, the main arena, the polling station, construction of a dedicated and the exhibition area. In the team, which will take care main arena registered healthcare of the content. On the other professionals can upload hand, well-organised vascular their scientific presentations, medicine e-learning platforms case reports, vascular images have been widely accepted. and reviews after a peerHowever, the main limitation Giovanni Torsello review process. In the polling of this form of e-learning is that station registered healthcare it remains industry-driven and it may not professionals can vote on a monthly basis on cover the questions about troubleshooting, controversial topics of vascular medicine and complications, and non-product related learn from the opinion of an invited expert. decision-making. Finally, in the exhibition area registered companies provide a comprehensive and Vascupedia: an e-learning credible product information according to the platform for all indication for use. All companies are equally Taking all the aforementioned issues into presented in alphabetical order. Hence, account, a multidisciplinary team of vascular every Vascupedian has a fair overview of all specialists and nurses created a global manufacturers regardless of the size of the e-learning platform called Vascupedia company or the number of products. in order to fulfil the need for free and comprehensive education in vascular Vascupedia in numbers medicine. The aim of Vascupedia is wellVascupedia celebrated its first year of online defined: to help physicians worldwide to presence on 1 June 2019. During this period, perfect their interventions and by this way to 22,566 users from 140 countries visited the indirectly contribute to safety and well-being website and 1,561 healthcare professionals of patients with vascular diseases. were registered as Vascupedians. Without doubt, these numbers highlight that The structure of Vascupedia Vascupedia succeeded to fill a relevant gap Vascupedia is accessible and free for in the daily practice of vascular specialists everybody worldwide. However, only worldwide. registered healthcare professionals can In my opinion, the secret of this success is that this platform has been made by physicians for physicians, whilst trying to maintain an element of the traditional way of training and education. Giovanni Torsello is a vascular surgeon at St Franziskus Hospital in Münster, Germany.
See Vascupedia webinar on ‘Clinical decision-making in AV fistula maintenance’
November 2020
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Trial results
The IN.PACT AV Access results: A game-changing trial
Andrew Holden talks through the “game-changing” results of the IN.PACT AV Access trial. CHRONIC RENAL FAILURE IS A global health and economic burden with increasing numbers of patients requiring renal replacement therapy. Currently, plain balloon angioplasty is the primary treatment for AV circuit stenosis but these lesions are fibrotic and often refractory, requiring high pressure or specialty balloons to adequately dilate. Of more concern is the extremely high rate of restenosis, with many studies reporting a primary patency of about 50% at six months. Given the proven patency advantages of drug-coated balloons (DCBs) in the femoropopliteal and other arterial beds, it is not surprising that there has been considerable interest in evaluating DCBs in AV access circuit intervention. Initially, the use of DCBs in AV access intervention was reported in single centre studies characterised by small patient numbers. Although a trend toward better patency was reported with DCBs compared to plain balloon angioplasty, the confidence intervals were wide and some studies failed to show a benefit. There was considerable heterogeneity in technique reported in the studies, particularly the requirement and quality of vessel preparation prior to DCB deployment. These studies reinforced the need for large multicentre, well-powered randomised studies. The BD-Bard Lutonix AV Access IDE trial was the first such trial, randomising 285 participants to either DCB or plain balloon angioplasty after satisfactory pre-dilatation with a high-pressure balloon. Unfortunately, the trial did not meet its primary efficacy endpoint of six-month primary target lesion patency although the patency advantage of DCB did reach statistical significance at other time points. IN.PACT AV Access is a multicentre, multinational randomised controlled trial of 330 participants evaluating the safety and effectiveness of the IN.PACT AV DCB compared to plain balloon angioplasty after successful pre-dilatation with a high pressure balloon (defined as a residual stenosis < 30% diameter loss). The IN.PACT AV DCB is based on the 0.035” IN.PACT Admiral DCB with a paclitaxel dose of 3.5µg/mm2 (Figure 1). The device is available in diameters
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between 4mm and 12mm and balloon lengths between 40mm and 150mm. The catheter shaft includes 40cm, 80cm and 135cm lengths, the short catheter length particularly useful in many AV interventions. The IN.PACT AV Access trial included independent and blinded duplex ultrasound and angiographic core laboratories as well as a clinical events committee and was conducted in the USA, Japan and New Zealand. Participants treated in the trial had lesions in native AV fistulae with a lesion length of less than 10cm with a target vessel diameter between 4mm and 12mm. Baseline clinical and lesion characteristics were well-matched between participants in each treatment group, although the target lesion was significantly longer in the DCB group (mean length 46.9mm vs 40.0mm, p=0.021). Half of the participants in both groups had a radiocephalic fistula with the remainder primarily being upper arm access circuits (brachiocephalic and brachiobasilic). The type of lesion (de novo versus restenotic) as well as location within the access circuit were also evenly distributed. Device success (the ability to introduce the device and deploy to nominal diameter) was 100% in both groups
and all participants were able to resume successful dialysis. The primary endpoint results were first presented in 2019 at the meeting of the Cardiovascular and Interventional Andrew Holden Radiological Society of Europe annual meeting (CIRSE; 7–11 September, Barcelona, Spain), and were recently published in the New England Journal of Medicine. The IN.PACT AV Access trial is the first randomised DCB in AV access study to meet it is primary effectiveness endpoint and did so impressively (Figure 2). This primary effectiveness endpoint was sixmonth target lesion primary patency (TLPP), defined as freedom from clinically-driven target lesion revascularization (CD-TLR) or access circuit thrombosis measured through six months post-procedure and was measured to 210 days. A target lesion primary patency of 82.2% was achieved in the DCB group compared to 59.5% in the standard PTA group with a p-value <0.001). The six-month rate of CD-TLR was also significantly lower for participants treated with a DCB (16.4% vs 38.5%, p<0.001) as was the entire access circuit patency (73.2% vs 48.0%, p<0.001). These outstanding efficacy results are likely to significantly impact the management of patients on haemodialysis. Any meaningful improvement in primary patency and reduced reintervention is relevant for haemodialysis patients whose quality of life is already challenged by the need to have regular dialysis. In the IN.PACT AV Access study,
Figure 1. The IN.PACT Admiral DCB
Figure 2. Primary effectiveness and safety endpoints for the IN.PACT AV Access trial
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IN.PACT AV Access
there was a 56% reduction in the number of interventions required to maintain patency through 210 days in patients treated with a DCB compared to the control group. In the 170-participant group randomised to the DCB, there were only 40 reinterventions by six months compared to 91 reinterventions in the 160-participant standard angioplasty group. There was also a 47.6% reduction in the number of reinterventions required to maintain entire access circuit patency. This reduced reintervention rate resonates with clinicians, funders and patients alike and it would not be surprising to see DCB angioplasty become the standard of care for AV access stenosis intervention. There has been considerable discussion around the impact of AV access stenosis type, fistula type and stenosis lesion location on outcomes after angioplasty, including DCB angioplasty. There have been suggestions that stenoses occuring in forearm radiocephalic fistulae respond better after angioplasty than stenoses in upper arm fistulae including brachiocephalic and brachiobasilic access circuits. It is also known that stenoses in certain locations in the access circuit respond less well to angioplasty and have higher rates of restenosis. The AV anastomosis and the cephalic arch are particularly problematic locations in this regard. Recently, sub-group analysis data of the IN.PACT AV Access study was presented at the Vascular Interventional Advances 2019 conference (VIVA; 4–7 November, Las Vegas, USA). A significant patency advantage for DCB was seen in both de novo and restenotic lesions and all types of AV access. In particular, both radiocephalic and brachiocephalic AV access stenoses showed
Figure 3. Patency outcomes by lesion location through six months in the IN.PACT AV Access trial
a similar patency advantage after DCB angioplasty. Lesion location was defined by the Angiographic Core Laboratory into six locations—arterial inflow, anastomosis, swing point, in cannulation zone, venous outflow and cephalic arch. In a subgroup analysis by lesion location (Figure 3), it was pleasing to note a patency advantage for DCB in all access circuit lesion locations, especially the AV anastomosis and cephalic arch.
These exciting results are now published in NEJM.” One of the interesting findings in the IN.PACT AV Access study is how well the standard angioplasty group performed. A six-month target lesion primary patency of 59.5% is better than has been reported in the experimental group of many AV access device trials, including specialty balloons, covered stents and other DCBs. This suggests that the careful vessel preparation achieved by high pressure balloon angioplasty in trial should be replicated in clinical practice (Figure 4). It is also impressive that the AV DCB could still achieve such a highly significant patency advantage despite this excellent conventional angioplasty performance. It is important to note that the primary safety endpoint in the IN.PACT AV Access study, serious adverse events involving the access circuit within 30 days, was low and not significantly different between the DCB arm and standard angioplasty arm (4.2% vs. 4.4%). There have been recent concerns regarding
the safety of paclitaxel drug-coated devices, particularly in femoropopliteal arterial interventions. There should be caution in extrapolating this data into the use of paclitaxel based DCBs in other vascular beds and for different clinical indications. The life-expectancy of these patients may be very different to a claudicant population and the benefits of a patent vessel even more profound. In the USA, it is estimated the two-year mortality for haemodialysis patients is 33.2%, more than twice that of a claudicant population. A recently published metaanalysis of mortality after paclitaxel-coated devices in AV access showed no difference in short to mid-term mortality for DCBs compared to plain balloon angioplasty. The 12-month mortality results in the IN.PACT AV Access Study were almost identical in the DCB and control groups with Kaplan-Meier survival of 90.6% vs 90.4%. In conclusion, the IN.PACT AV Access Trial is the first DCB trial in AV access intervention to meet both its primary efficacy and safety endpoints, and promises to have a profound effect on the management of patients on haemodialysis. The device received US Food and Drug Administration (FDA) premarket approval in November 2019. Twelve-month results and cost effectiveness data were presented in 2020, and patients will be followed to five years. Andrew Holden is director of interventional services at Auckland City Hospital in Auckland, New Zealand. References for this article can be found on www.vascularnews.com
Figure 4. Use of the IN.PACT AV DCB in a routine clinical case. 56 year-old male on haemodialysis for three years via a right brachiocephalic AV fistula.
All rights reserved. Published by BIBA Publishing, London T:+44 (0)20 7736 8788, publishing@bibamedical.com. The opinions expressed in this supplement are solely those of Medtronic and the featured physicians and may not reflect the views of Vascular News.
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