The WavelinQ™ EndoAVF System takes an innovative approach in creating EndoAVF by BIBA Publishing

24 WavelinQTM EndoAVF System: The radial approach from a vascular surgery perspective / Advertorial

September 2021 | Issue 83

The WavelinQ™ EndoAVF System takes an innovative approach in creating endovascular AV fistula (endoAVF) for dialysis patients. Rethink fistula creation and maintenance with Tobias Steinke, Ounali Jaffer, Panagiotis Kitrou and Robert Jones in this four-page advertorial, sponsored by BD.

Minimally-invasive, outpatient WavelinQ offers an alternative to open surgery According to Tobias Steinke, head of Vascular and Endovascular Surgery, Schoen Klinik Duesseldorf, Duesseldorf, Germany, patients are often keen to undergo minimally invasive procedures and may prefer these to open surgical options. As a vascular surgeon, the WavelinQ System offers additional anatomic sites for percutaneous arteriovenous fistula (AVF) creation that may not compromise surgical alternatives, which is a really important aspect, according to Steinke.

multidisciplinary team involving nephrologists, vascular surgeons, interventional radiologists, anaesthetists, nurses and vascular technologists is key to approaching decision-making before AVF creation, says Steinke. “It is quite important that all the physicians involved in creating, using and maintaining AVFs communicate with each other. How quickly is this access required for needling? Which options allow the quickest needling of the access?” These are examples of questions that generate multidisciplinary discussion, he notes. “In our practice, if there is time and the patient is young, we prefer to begin with a surgical creation of a radiocephalic fistula, because long-term, if it works as intended, this will be the best option. If we have a Parallel: Access from upper arm (brachial artery/ brachial vein)

Target Creation Site

WavelinQ offers the option of creating EndoAVF at multiple creation sites in the forearm

patient who needs an access quite quickly, we usually move to the level of the elbow and again, surgically create a brachiocephalic fistula, which often has a shorter maturation time. The EndoAVF options can be used for patients who have vessels with accepted criteria, Tobias Steinke and work very well as they are positioned in the “middle ground” between the two surgical options at the wrist and above the arm,” explains Steinke. WavelinQ EndoAVF creation offers versatility in enabling multiple creation sites. “There are several anatomical options: lateral radial vein; medial radial vein; lateral ulnar vein; medial ulnar vein; and the location of the perforator plays a role as well. The target creation site should be as close as possible to the perforator to create conditions for the outflow to enable large amounts of blood to pass through these vessels for dialysis,” elaborates Steinke. “The case I am about to discuss involved a patient with end-stage renal disease. He had a surgically created radiocephalic fistula, which failed over time.

The next distal option to create another AVF, before going directly to the level of the elbow to create a brachiocephalic surgical fistula was at the lateral radial vein in direct connection with the perforator. The patient’s vessels were highly suitable for WavelinQ EndoAVF creation with the perforator optimally located to create a radial-radial fistula. In assessing vessel suitability for EndoAVF creation I always look at the diameter of vessels, location of the perforator and calcification. “Vessel mapping is mission critical. Operators really do have to understand the relationship between the arteries and veins in the arm and how the deep venous system is connected to the superficial venous system, especially with reference to the perforator vein. You have to construct a three-dimensional mind map of the venous and arterial system to establish the ideal location to create the AVF. So, proper vessel mapping, and really knowing how those veins are connected to each other is essential to be successful,” he concludes.

WavelinQ EndoAVF creation results in little or no disfigurement, which often convinces patients, especially those who refuse open surgery, to undergo the procedure.”

My procedural considerations

Target Creation Site

• Practising ultrasound puncture techniques is critical. There is a learning curve associated with this aspect, especially when puncturing the vein. Therefore, practice makes perfect. Moreover, procedural success also rests on puncturing the radial artery, which is usually pretty small (2mm) and this can also be challenging.

Parallel: Access from wrist (ulnar artery /ulnar vein or radial artery/radial vein)

• Always consider coiling during the procedure if the anatomy allows. Coils should be placed proximally to the created EndoAVF so that the venous outflow into the deep venous system is embolised and you direct the flow up to the superficial system. This can help facilitate maturation. • Always check the deep radial veins in different views that is parallel to the brachial artery above the elbow.

Anti-Parallel: Access from wrist (ulnar vein) and upper arm (brachial artery)

• Use the several connecting bridges from the medial to the lateral radial vein, which allow crossing from one side to the other to get the best parallel wire position during the procedure. Interventionalists may use those bridges to cross over with a guidewire to find the best catheter position. Some operators prefer to puncture the vein and then go straight up.

Target Creation Site Figure 1. Advancing venous catheter using a valve crosser to protect the electrode. Figure 2. The tissue gap before and after the delivery of radiofrequency energy. Figure 3. Post-creation fistulogram

• Aim to create the AVF as near as possible to the perforator.

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Advertorial / WavelinQ™ EndoAVF System: The wrist approach from an interventional radiology perspective 25

Patients’ wishes and multidisciplinary approach central to EndoAVF creation with WavelinQ “I am a firm advocate of informed patient choice whereby every patient is actively involved in the treatment that they actually receive. In the case described below, the patient went to see his nephrologist, having seen an article in the local newspaper about our hospital being the first to offer the endovascular arteriovenous fistula (EndoAVF) creation procedure within the UK’s National Health Service (NHS).

“T

he patient was then referred to our multidisciplinary clinic and all options were presented by the appropriate specialists, after which he remained set on having an WavelinQTM EndoAVF System,” says Ounali Jaffer, interventional radiologist and Interventional Radiology Research and Innovation lead at Barts Health, London, UK. “The rationale for choosing the EndoAVF approach in this particular patient was driven by the fact that he actively sought out the procedure but most importantly because it was the right option for him. While there were several other centres who had performed this procedure in a research setting, we at the Royal London were the first in the UK to offer the service on the NHS. The ensuing publicity, and our engagement with local patient groups have helped spread the message of this relatively novel treatment,” explains Jaffer, who is My procedural considerations • Adhere to the recommended guidelines in terms of vessel size—2mm or more in diameter at the access as well as the creation site for both the ulnar and the radial artery and concomitant veins. Outflow veins such as the cephalic need to be at least 2.5mm to allow for maturation. When screening, always start with assessment of the perforator vein as this may not be present in up to 15% of patients and ensure that is greater than 2mm. Especially when starting out, you have to be disciplined in the cases you pick by adhering to the guidelines and thereby minimising potential problems and maximising the chance of success in the first few cases.

My patient selection flowchart Patients considered healthy enough to have a standard endovascular procedure and an arteriovenous fistula qualify for further assessment

• Consider vascular anomalies. Sometimes there is more than one perforator. • When using the wrist approach, assess that both anatomically and physically (i.e. Allen’s or Barbeau test) to make sure it is suitable. • Ensure that postprocedure aftercare is very standardised. If reintervention is required, this should be done at the most optimum timepoint to reduce the risk of arterialisation to the deep veins or any maturation challenges. • When you perform a venogram and are unsure about the anatomy, especially above the elbow, remember you have an ultrasound in your hand. Use the two imaging modalities in conjunction to problem solve.

Perform ultrasound assessment – Tourniquet up – Patient has normal hydration

Confirmation of the creation site with identification of the perforator

also deputy director, Research, Group Clinical Services at the hospital.

Multidisciplinary team invested in EndoAVF critical to success

Jaffer also emphasises how vital the multidisciplinary approach is to the successful creation of EndoAVF. “We have a very defined, focused multidisciplinary team approach with nephrologists, vascular access surgeons, interventional radiologists, and very importantly clinical nurse specialists, lead dialysis nurses and vascular scientists. All of us are focused on building the success of the programme and ensuring it is patientcentric; at every stage, the patient’s voice will be heard and passed on to the other groups when relevant to do so. We have a weekly vascular access meeting in which all EndoAVF cases performed are discussed and all future options assessed.” Jaffer particularly draws out that decision-making is underpinned by the Kidney Disease Outcomes Quality Initiative (KDOQI) guidelines in that the fistula creation is geared to deliver the “right access, in the right patient, at the right time, for the right reasons”. From a practical standpoint, EndoAVF creation relies firmly on an incredibly robust ultrasound screening programme to ensure that the patient’s vasculature is suitable as anatomy obviously drives the choice of percutaneous device quite strongly, he clarifies. The team at Barts Health favours starting with the radiocephalic surgical option. “If this is a no-go, or has been used, then we always consider a percutaneous option before we go above the elbow. I think as time evolves, there will be an algorithm, which is specific to how we incorporate endovascular AVF creation, both in terms of the particular device used and how it fits in with surgical options,” Jaffer opines.

Ounali Jaffer

Avoidance of scars and additional anatomic locations for AVF creation

There are certain aspects that make the WavelinQ a very attractive option, and Jaffer particularly draws out the lack of creation scarring, versatility in terms of future surgical options and ease of use. “We cannot underestimate or discount the impact of haemodialysis on a patient’s life. Often, life has been turned on its head for patients. They are suddenly having to go to a hospital or a dialysis centre thrice a week, which has a tremendous psychological effect. With the percutaneous Upper arm vein(s) ≥2.5mm diameter?

Perforator present, feeding upper arm vein(s)?

Perforator vein on ultrasound

Post-creation arteriogram

approach, firstly, you avoid surgical creation scarring, which is an important factor for many people, and it might be the reason that they are refusing to have a surgical option and choose instead to stay on a line, which traditionally has much higher rates of morbidity and mortality. “Secondly, with the WavelinQ EndoAVF System, you can get a split flow, or maturation of two veins, which may lead to a longer length than you would with above-arm fistulas in terms of areas that you can cannulate. The procedure I performed did not take away future surgical options. Indeed, it simply provides choices for AVF creation for patients who have a finite number of alternatives. In my opinion, the WavelinQ device is user friendly in terms of the actual procedure,” he says. Furthermore, WavelinQ is a complete programme in that the screening, AVF creation and post-procedural aspects such as maturation and cannulation are equally important. “Every aspect along the entire pathway has to be completely on the ball to get to that patency rate that you are looking for. There is obviously a learning curve, as with any device, but this is relatively quick and the support from the company, for the procedure, preprocedural planning, and the postprocedural maturation and cannulation aspects is very good,” he notes. Brachial, radial or ulnar artery ≥2mm diameter? At least one brachial vein ≥2mm diameter?

Not an EndoAVF candidate

At least one ulnar or radial vein ≥2mm diameter?

EndoAVF candidate

Not an EndoAVF candidate

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26 WavelinQTM EndoAVF System: The antiparallel approach / Advertorial

Screening with ultrasound and vessel mapping prerequisite to success with WavelinQ™ EndoAVF System Focusing on the importance of vessel mapping and its impact on his team’s choice of WavelinQ for EndoAVF creation, Panagiotis Kitrou, assistant professor in interventional radiology at Patras University Hospital in Patras, Greece, says: “Screening of the patient with ultrasound is a prerequisite. This is true not only for percutaneously created fistulas but also for those created surgically.”

“W

hen using WavelinQ in particular, apart from being the main exam for eligibility, it also offers the ability to plan the procedure in terms of access. There is also the advantage of coming up with a back-up plan, as in most cases, more than one access option is available.”

Emerging evidence in support of EndoAVF

Commenting on the data evolving in 2021 to back EndoAVF, Kitrou asserts that this is “still in its infancy”. “There are few studies available, and the number of patients recruited in these studies is still small, but the initial results are very encouraging. However, BD has an extensive clinical programme regarding WavelinQ with two studies, the CONNECT-AV in the USA and the WAVE-Global, set to recruit more than 400 patients and aiming to provide a significant amount of evidence regarding the technology. CONNECT-AV is a prospective, single-arm, open-label study that will follow patients treated with My procedural the WavelinQ EndoAVF considerations System for 24 months. The study’s dual primary • No shortcuts! Because of the effectiveness endpoints are versatility of options the percentage of patients provided both for dialysing using successful creation and access two-needle cannulation for with WavelinQ, one should respect all at least 75% of the dialysis the steps of the sessions over a continuous procedure. 28-day period at six months, and the patients

maintaining primary patency at six months. The primary safety endpoint is freedom from device and procedure-related serious adverse events through 30 days. The trial is expected to enrol 280 patients in the USA. Panagiotis Kitrou Similarly, WAVE-Global is a prospective, single-arm, open-label study that will follow patients treated with the WavelinQ EndoAVF System for 24 months. The primary endpoints are the number of interventions needed post-creation to facilitate and/or maintain AV fistula use at six months, and the proportion of participants with freedom from clinical events committee adjudicated device- or procedure-related serious adverse events at 30 days. The trial is expected to enrol 150 participants globally (outside of the USA).

Choosing EndoAVF and the antiparallel approach

An important consideration when making the choice to perform percutaneous AVF creation, for Kitrou, is that it is not antagonistic to surgical fistula creation. “It is complementary and provides additional options for AVF creation for the patient. The WavelinQ device in particular offers four potential added sites for anastomosis. Moreover, EndoAVF creation may not compromise future surgical options.” Specifically commenting on the different approaches, Kitrou says: “Once the vessels of creation are decided, the vessels of access should be chosen. I prefer accessing

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the wrist vessels. In the case of the artery, the wrist is more superficial, enabling an ease to post-intervention compression. When venous puncture is undertaken, wrist access is antegrade to venous flow. This may offer better opacification of the venous network and better valve negotiation compared to brachial access. If one of those is not possible, then brachial access is the next choice and this leads to the antiparallel approach. Again, I would like to emphasise that vessel mapping is a prerequisite and a key to success.” Kitrou explains how the development of EndoAVF has provided interventional radiologists with the option to perform fistula creation. “In my centre, as an interventional radiologist I was not involved in fistula creation in the past. This percutaneous option has allowed our discipline to get involved. We have extensively discussed the matter in our dialysis multidisciplinary meeting and decided to include WavelinQ into our algorithm three years ago. Every decision we make to create an EndoAVF is a multidisciplinary decision. Additionally, when patients are offered a less-invasive option, they often prefer it to the surgical option. We have now treated more than 40 patients, in a hospital that was never a reference centre for AVF creation, and the results, so far, are encouraging.”

Percutaneous AVF creation is not antagonistic to surgical fistula creation. It is complementary […] WavelinQ, in particular, offers four potential extra sites for anastomosis.”

Figure 1. Image of the patient’s left hand. Arrows show the antiparallel approach with the arterial puncture from the wrist (ulnar artery) and the venous puncture from the upper arm (lateral brachial vein) Figure 2. Catheter alignment at the level of the forearm prior to activation Figure 3. Final fistulogram showing the different parts of the vascular access circuit. Following the blood flow: ulnar artery > anastomosis > lateral ulnar vein > perforator > cephalic vein/median cubital vein – basilic vein. The coiled lateral brachial vein is also indicated

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Advertorial / WavelinQ™ EndoAVF System: Secondary interventions 27

Utilising angioplasty to treat stenosis post EndoAVF Reinterventions following WavelinQ™ EndoAVF System creation may be required. The go-to procedure remains balloon angioplasty. Angioplasty in this setting is occasionally needed to treat stenosis of the perforator and deep vein segment adjacent to the arteriovenous (AV) communication.

obert Jones, consultant interventional radiologist at the Queen Elizabeth Hospital, Birmingham, UK, says: “Our experience has revealed that secondary interventions—primarily angioplasty, are effective if a stenosis develops and, less commonly, embolization of venous tributaries is required for diverting flow superficially to aid fistula flow and maturation. In a data-scarce field, a “typical” timeframe for reinterventions is hard to pinpoint with accuracy at this stage. We have learnt a lot about secondary interventions after WavelinQ EndoAVF at my centre and are in the process of analysing our data.” The two main categories that secondary reintervention fall into, in Jones’s practice, are those aimed at promoting maturation, and those to maintain patency, such as angioplasty of problematic stenoses. He also clarifies that some WavelinQ EndoAVF failing to mature may be the result of stenosis that develops early on. With increasing experience and understanding in the relatively new and novel space of EndoAVF creation and maintenance, the approach to secondary treatment is evolving, he clarifies. “Early on, when we identified small numbers of EndoAVF that failed to mature, we followed a protocol of coil embolizing deep veins or collaterals to promote maturation. I now wonder whether we were overlooking underlying subtle stenosis at the time,” says Jones, who is also the treasurer of the Vascular Access Society of Britain & Ireland (VASBI). With the WavelinQ EndoAVF system offering many options for fistula creation at multiple anatomical sites in the proximal forearm (ulnar-ulnar vein or radialradial), Jones makes the point that further experience will be required to determine whether there is a difference regarding the types of problems that emerge, and reinterventions needed between the two sites of fistulas. Explaining the evaluations used to guide any secondary interventions, Jones identifies reviewing fistula creation angiograms; relevant ultrasound findings; assessing the clinical status of the patient; and the functional status of the fistula as key considerations before planning the procedure. “The first thing I would want to review is the imaging from the original fistula creation. Secondly, I would assess the current clinical

and dialysis information in conjunction with previous imaging. Was the patient dialysing well before the problem arose, or is this an issue of poor function and maturity from the beginning? Then, I would look at any Robert Jones current and relevant ultrasound findings to assess whether the fistula is still patent or not, because that is an important consideration,” he says. Jones elaborates that while the principles of reintervening in surgical fistulas are similar to those created percutaneously. With the latter, the approach needs to be more tailored to the individual patient in terms of the configuration of the fistula and location of problem. “With WavelinQ EndoAVF, the AV communication is side-to-side, there are multiple outflow veins and therefore the anatomy is very different to the traditional wrist or above elbow surgical fistula. Traditionally, for a dysfunctional surgical fistula, we would perform an

ultrasound/Doppler in the first instance to establish whether there is a stenosis or occlusion. With a WavelinQ EndoAVF, because there are multiple outflow veins, and the location of the AV communication is deeper, the problem can be more challenging to precisely identify with ultrasound but this is still an important, non-invasive, first-line investigation, especially in assessing brachial artery inflow rates. A subtle stenosis in the deep veins in proximity to the AV communication could easily be overlooked with ultrasound. You really need an

• Carry out a diagnostic fistulogram from the arterial side in the first instance and it is useful to have a higher digital subtraction angiography frame rate when performing the angiogram, with oblique projections often helpful.

• If there is a stenosis, it is often observed in the juxta-arteriovenous communication deep vein or perforator, rather than the outflow veins. Scrutinise this region in detail. • My preferred approach to intervention is a separate venous access to avoid upsizing the arterial access. • Aim for a ‘straight-shot’ to the problem—plan to treat any stenosis or coil embolizations via the straightest possible route, as it can be challenging to negotiate tortuous anatomy, especially via the AV communication.

Case for secondary intervention

The patient is a 70-year-old man with a left ulnarulnar WavelinQ EndoAVF created in 2018. The patient had had previous secondary interventions, previous angioplasties of the perforator vein and juxtaanastomotic lateral ulnar vein since fistula creation to treat recurrent stenosis. Each of these interventions resulting in significantly improved dialysis function. He recently reported difficulty in needling the fistula and poor thrill. There was also a drop in brachial artery flow demonstrated on ultrasound from a baseline of 1,600ml/min to 450ml/min. These were the indications for intervention.

WavelinQ™ Venous and Arterial Catheter

My procedural considerations

• Carefully ascertain whether there is a stenosis; or are there competing venous outflow issues?

angiogram from the arterial side to get a clear idea of what is happening. “Firstly, I either puncture the relevant artery at the wrist, or the brachial artery above the elbow, with a micropuncture set and carry out a diagnostic fistulogram to establish whether there is a stenosis and to assess the outflow dynamics to ascertain if there are competing deep veins or collaterals that may have developed that could be stealing flow from the superficial veins. This diagnostic fistulogram then allows planning of interventions—angioplasty (to treat stenosis) or coiling (to embolize deep veins or collaterals to promote more superficial flow to the cannulation sites). Often, a second access point is called for. So rather than approaching a stenosis, for example, from the arterial access that has been gained to obtain the diagnostic angiogram, we might need to obtain access in the relevant outflow vein,” he emphasises.

Figure 1. Pre-angioplasty angiogram

Figure 2. Post-intervention angiogram demonstrating improved appearances

Following a diagnostic fistulogram from the arterial side, Jones gained retrograde access in the cephalic vein in the upper arm and performed an angioplasty of the perforator stenosis in a straight-line fashion, without having to cross the AV communication (Fig 1 and 2).

The go-to procedure remains balloon angioplasty. Angioplasty in this setting is occasionally needed to treat stenosis of the perforator and deep vein segment adjacent to the arteriovenous (AV) communication.”

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28 Advertorial

Disclaimer: Please consult Becton, Dickinson and Company product labels and inserts for any indications, contraindications, hazards, warnings, cautions and instructions for use. The opinions and clinical experiences presented herein are for informational purposes only. The results from this case report may not be predictive for all patients. Individual results may vary depending on a variety of patient specific attributes. The clinicians have been compensated by Becton, Dickinson and Company to participate in this presentation.

WavelinQ™ EndoAVF System (WavelinQ™ System, WavelinQ™ or REF WQ4305) Components

INDICATIONS: The WavelinQ™ EndoAVF System is intended for the cutting and coagulation of blood vessel tissue in the peripheral vasculature for the creation of an arteriovenous fistula used for hemodialysis. CONTRAINDICATIONS: Known central venous stenosis or upper extremity venous occlusion on the same side as the planned AVF creation. Known allergy or reaction to any drugs/fluids used in this procedure. Known adverse effects to moderate sedation and/or anesthesia. Distance between target artery and vein > 1.5 mm. Target vessels < 2 mm in diameter.

WARNINGS: The WavelinQTM EndoAVF System is only to be used with the approved commercially available devices specified in the IFU. Do not attempt to substitute non-approved devices or use any component of this system with any other medical device system. The WavelinQTM EndoAVF System catheters are single use devices. DO NOT re-sterilize or re-use either catheter. Potential hazards of reuse include infection, device mechanical failure, or electrical failure, potentially resulting in serious injury or death. Use caution when performing electrosurgery in the presence of pacemakers. Improper use could damage insulation that may result in injury to the patient or operating room personnel. Do not plug device into the electrosurgical pencil with ESU on. Keep active accessories away from patient when not in use. Do not permit cable to be parallel to and/or in close proximity to leads of other devices. Do not wrap cable around handles of metallic objects such as hemostats. Consult the ESU User’s Guide on its proper operation prior to use. Do not use closure devices not indicated to close the artery used for access. CAUTIONS: Only physicians trained and experienced in endovascular techniques should use the device. Adhere to universal precautions when utilizing the device. Do not kink, pinch, cut, bend, twist, or pull excessively or with excessive force on any portion of the devices. Damage to the catheter body may cause the device to become inoperable. Avoid sharp bends. This may cause the device to become inoperable. Do not pinch or grasp the catheter

with excessive force or with other instruments. This may cause the device to become inoperable. Do not bend the rigid portion of the catheter near the electrode or backstop. Do not touch or handle the active electrode. Electrode dislodgement may occur. Always use the hemostasis valve crosser to assist insertion of the venous catheter through the introducer sheath. Insertion into introducer sheath without hemostasis valve crosser may damage electrode. Do not attempt to remove the hemostasis valve crosser located on the venous device. Device damage or fracture may occur. PRECAUTIONS: Care should be taken to avoid the presence of fluid on the ESU. Care should be taken during handling of the arterial and venous catheters in patients with implantable cardiac defibrillators or cardiac pacemakers to keep the distal 3 inches of the catheters at least 2 inches from the implanted defibrillator or pacemaker. Care should be taken to avoid attempting fistula creation in a heavily calcified location of a vessel as fistula may not be adequately formed. The safety and performance of this device has not been established for pediatric patients. If the device does not perform properly during the creation of the endovascular fistula it is possible that a fistula will not be created or there may be some vessel injury. Keep magnetic ends of catheters away from other metallic objects which may become attracted and collide with devices.

POTENTIAL ADVERSE EVENTS: The known potential risks related to the WavelinQ™ EndoAVF System and procedure, a standard AVF, and endovascular procedures may include, but are not limited to: aborted or longer procedure; additional procedures; bleeding, hematoma, or hemorrhage; bruising; burns; death; electrocution; embolism; failure to mature; fever; increased risk of congestive heart failure; infection; numbness, tingling, and/ or coolness; occlusion/stenosis; problem due to sedation or anesthesia; pseudoaneurysm; aneurysm; sepsis; steal syndrome or ischemia; swelling, irritation, or pain; thrombosis; toxic or allergic reaction; venous hypertension (arm swelling); vessel, nerve, or AVF damage or rupture; wound problem. Please consult product labels and instructions for use for all indications, contraindications, hazards, warnings and precautions.

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