Building an EndoAVF Program

Bulent Arslan, MD, FSIR, Professor and Director, Vascular and Interventional Radiology, Rush University Medical Center, Chicago, Illinois, started an endovascular arteriovenous fistula (AVF) program at his institution about 2 years ago. During an International Symposium on Endovascular Therapy (ISET) 2021 session on AV access, he shared some pearls and pitfalls with attendees.

One of the key components, not surprisingly, is creating a referral pathway. “Most vascular surgeons have an established pathway already, so it’s not a big deal for them, but for an interventionalist who hasn’t been involved in the creation of the fistula, they need kind of a start-up [mentality] and they need to identify patients,” he said.

Training on patient selection and mapping, the procedure, and appropriate follow-up are other key components, but both of the companies that provide endoAVF devices offer in-house team training. Important skills to master include the ultrasound evaluation and support for cannulation, Dr. Arslan noted, “because the cannulation is not just like the surgical AV fistulas, it requires a little bit more training and adjustment.”

“To build the program, you need to be good at the procedure. If you’re not good at the procedure, it’s not going to work. And you also need to convince your referring physician that you're good at it,” he said. Better assessment is key to better success rates — don’t rush into doing this on every patient," he stressed.

If you already have an established relationship with referring physicians, that obviously helps get things going, but even then you may need to do some work to convince them that the endovascular option is a good one, said Dr. Arslan.

There are currently two endoAVF device options: Elipsys (Avenu Medical) and WavelinQ (BD). “Both have technical nuances that require decent interventional and imaging skills, and both has advantages and disadvantages. Whereas Ellipsys is somewhat easier to use and doesn’t require arterial access, it has a relatively smaller patient candidacy. WavelinQ, on the other hand, is more complicated requiring arterial access and dealing with valves, but provides more options and larger patient candidacy," Dr. Arslan summarized.

“In my mind, they're more complimentary than competitive. There's definitely a group of patients for whom you can use both devices, but there’s usually, as you get into the details of the procedure, there is usually a better option for each patient.”

WavelinQ

The WavelinQ system used to be a 6 French device and is now 4 French, which has reduced arterial access site complications. “With the 4 French, that’s been reduced significantly, but you still have to get both of the catheters aligned in the artery and vein, and that’s how you produce the fistula,” said Arlsan, walking the audience through the basic procedural steps.

First step: preoperative ultrasound assessment. “Again, very important to choose the right patients.” Venous access can be obtained either antegrade or retrograde. If you do antegrade access, you need to be able to navigate the valves to get into the target area. With retrograde, the vessels are small, “but I’ve done on occasional retrograde access even with the 6 French.”

“It can be confusing if you haven’t assessed the arterial system very well, so both arterial and venous anatomy needs to be worked out very well,” he said.

“And then you need to position the electrode and ceramic catheters and make sure they are in a good position to create the fistula. One you confirm that with fluoroscopy — because these magnets have to be completely facing each other — if you’re not confirming this with 90-degree angle that they are aligned perfectly, you may just be creating a pseudoaneurysm or perforation rather than creating a fistula between the vein and the artery.”

Once alignment is confirmed, “you activate the device, and on the way out you embolize the brachial vein access site to divert more flow into the superficial system.”

His group has been able to offer WavelinQ to almost 80% of their patients. One advantage, Dr. Arslan noted, is that it can be used to create an ulnar-to-ulnar fistula. “The good thing about the ulnar is that nobody uses the ulnar, so it's a good place for a patient to potentially have a fistula.”

Ellipsys

The Ellipsys device is a single catheter access, 6 French device. It has a power controller and creates a fistula through a thermal process, reported Dr. Arslan.

Again, ultrasound assessment is very important, but with the Elipsys “you need to make sure that there is a good size perforator [vein], at least 2.5 to 3 millimeters, and then it connects with the cephalic vein, because your access will be right at that confluence. You're going to thread a micropuncture under ultrasound guidance through the perforator, which is supposed to be on top of the radial artery, and you get into the radial artery.”

It looks a little bit cumbersome, he acknowledged, but with good ultrasound skills it can be done. “And once you do that step, the rest of the procedure is a lot easier and requires only a venous access.”

At the end, the angioplasty of the anastomosis with the 5 mm balloon has reduced thrombosis rates significantly. “It kind of worries me to have a 5 mm balloon in the radial artery, but so far we haven’t had an issue.”

Ultimately, it’s important to learn and master both procedures and be able to offer both to your patients, he stressed.

With a few more pearls of wisdom, Dr. Arslan concluded by stating that, at his center, they’ve done 30 cases, 29 successfully. Their reintervention rate is about 25%, he said.