Intro: Welcome to UAB MedCast, a continuing education podcast for medical professionals, providing knowledge that is moving medicine forwards. Here's Melanie Cole.

Melanie Cole, MS (Host): Welcome to UAB MedCast. I'm Melanie Cole. And today, we're delving into Interventional Endoscopic Ultrasound: Current and Future Directions. And joining me is Dr. Ramzi Mulki. He's an interventional endoscopist and an Assistant Professor at UAB Medicine. Dr. Mulki, it's a pleasure to have you join us today. Before we begin, can you provide an overview of how interventional endoscopic ultrasound has really evolved in recent years? Tell us what it is.

Dr. Ramzi Mulki: Yes. Thank you, Melanie, for having me. Well, endoscopic ultrasound was developed in the 1980s. And 1982 was actually the first radial echo-endoscope, which it's a scope that has a camera and an ultrasound probe that is passed through the upper GI tract or the lower GI tract, and you're able to see structures beyond the wall of the GI lumen.

And so in the 1980s, it developed into a purely diagnostic modality, where we were able to look at structures that are outside the GI tract, and we're able to diagnose different diseases. And then, in the 1990s, the linear echo-endoscope was developed. It's a different kind of echo-endoscope, but this one has what we call a working channel where you're able to pass tools and devices, most of which were diagnostic tools for like fine-needle aspiration of tissue.

And then, in the 2000s, the linear echo-endoscope has developed into larger working channels where now we can pass therapeutic devices through them and do more therapeutic-type interventions. And so, you know, it has really evolved over the past years. Even the number of publications going back from 1993 all the way to very recently has increased in the literature, and I had the pleasure to serve on the ASGE GI editorial board. And every year since 2020 up to 2022, we were writing articles, and the top trend was interventional endoscopic ultrasound in these publications. And so, it's an expanding field and it's an exciting time.

Melanie Cole, MS: Well, it certainly is. And I'd like to talk about the most common interventional uses for it, but how does it differ from what we've had in the past from diagnostic endoscopic ultrasound? Compare and contrast for us.

Dr. Ramzi Mulki: So, diagnostic endoscopic ultrasound has a specific type of scope. And so, at that point, you know, you're using a smaller channel, you're using fine-needle aspiration needles to be able to biopsy. Now, with the advent of newer technology, specifically larger caliber working channel scopes, but in addition to technology like stents and wires and different aspects like that, we're able now to do more luminal interventions.

And I think one of the major change was the lumen-apposing metal stent, which was developed in 2004, which really changed the way we approached interventional EUS. It was designed for pancreatic fluid collections. But we've used it, or we have been using it now for other interventional luminal procedures.

Melanie Cole, MS: Well, why don't you expand on that for us then, Dr. Mulki. What are the most common interventional procedures offered through the umbrella? And you and I discussed this at a different time, that umbrella of endoscopic ultrasound, how are they grouped? Tell us a little bit about that.

Dr. Ramzi Mulki: So, therapeutic EUS or interventional EUS, for example, in patients that have acute pancreatitis or pancreatic fluid collections, we're able to minimally invasively drain these collections within the GI tract. And in the past, we were limited to open surgery, which was very morbid, had a high mortality. And so, therapeutic EUS has been able to accomplish that. In addition, there are several biliary interventional procedures where now in patients that are non-surgical candidates for gallbladder drainage, we're able to provide them internal drainage.

Another example is bile duct access if patients that undergo ERCP that was unsuccessful were able to drain their bile duct using different modalities. In addition, we're able to perform what we call transluminal anastomosis. An example would be performing an endoscopic ultrasound-guided gastrojejunostomy. This essentially connects the stomach to the small intestine in patients that mostly have malignant gastric outlet obstruction. But also in patients in the recent obesity epidemic, we're seeing more and more patients with a Roux-en-Y gastric bypass. And we're able to bypass the stomach in a procedure called endoscopy-directed transgastric intervention where we also place this lumen-apposing metal stent to be able to access the excluded stomach.

There's also been a lot of expansion in endo-hepatology where we're now able to measure portal venous pressure, coil gastric varices, and recently, oncologic therapy as well, which, you know, we're able to provide chemotherapeutic agents directly into tumors. So, there's a lot of interventional endoscopic ultrasound procedures that have really revolutionized the field of GI.

Melanie Cole, MS: Isn't this an exciting time in your field and what a fascinating conversation we're having. Along those lines, are there any main risks that you can point out? How have advances in technology or technique helped to mitigate some of these? Tell us a little bit about some of the recent advances to minimize any complications.

Dr. Ramzi Mulki: So, I think, one of the main thing is training. You know, there's a lot of focus on being able to do these procedures safely. And in order to do that, you really have to have training in interventional GI. So, GI fellowship is three years of training. Beyond that is an interventional endoscopy year of training. So, you need to be able to do that. In addition, there's plenty of courses out there for people to learn that. But I think more importantly is being in a center of excellence where you have good surgical oncologists or excellent surgical oncologists, interventional radiologists, radiologists, and a core team of interventional GI to all work together, because the risks are high and what's unique about interventional EUS is that every patient has its specific risks and intricacies that we have to look into. And being in a center like UAB where there's a multidisciplinary approach to this is extremely important.

Melanie Cole, MS: Well, you're getting to my next question there, Dr. Mulki. In what areas of interventional endoscopic ultrasound do you see the most promising opportunities for this interdisciplinary collaboration and that multidisciplinary approach as we look at Oncology, Radiology, Surgery? Why is it so important for that specialized center to be able to do these procedures and use that approach?

Dr. Ramzi Mulki: Yeah, I think there's a lot of research that's going into interventional EUS. I think there's more tools that are being developed now that are going to make this procedure safer. In addition, I think that working in a multidisciplinary fashion with surgeons and interventional radiologists. And having a strong core interventional endoscopy program really is important and key for successful outcomes and minimizing adverse events. I think that's one of the main key points.

Melanie Cole, MS: Tell us where new technologies are so exciting, like artificial intelligence and advanced imaging. How are these likely to have the greatest impact on the future of endoscopic ultrasound?

Dr. Ramzi Mulki: Right. So, I think there's a lot of opportunities with artificial intelligence. You know, there has been recent advances from a diagnostic standpoint with EUS and AI. However, as the field continues to evolve, I think there's going to be a utility to do interventional EUS procedures safely with the assistance of artificial intelligence for sure. In addition, I think there's going to be more tools, such as stents and wires and different products and devices that are going to make this procedure safer and much more reproducible.

Melanie Cole, MS: Well, I think those are such important points that you made, Dr. Mulki. And as we get ready to wrap up, are there any ongoing or upcoming clinical trials you're excited about that are focusing on new interventional endoscopic ultrasound techniques? Wrap it up for us.

Dr. Ramzi Mulki: Yeah. I think interventional endoscopic ultrasound is a very large umbrella of various procedures that are available. I think there's more to come when it comes to radiofrequency ablation, for example, of tumors. I think there's a lot of potential opportunities there, especially in this area, when we're talking about pancreatic cancer, for example. So, I think that's an exciting time. Just recently, two days ago, there was a publication by a ASGE on the use of interventional endoscopic ultrasound and bile duct drainage. And I think, you know, this is a growing and expanding field, and I think it's a great opportunity to be involved and contribute to the research.

And lastly, I'd like to mention that, being at a center of excellence with high volume interventional endoscopic ultrasound, having a very strong interventional endoscopy team, with very advanced technological advancements in our endoscopy unit really is key and important to make these procedures successful and safe.

Melanie Cole, MS: All true. And thank you so much, Dr. Mulki, for joining us today and sharing your incredible expertise. And for more information, you can always visit our website at uabmedicine.org/physician. That concludes this episode of UAB MedCast. I'm Melanie Cole. Thanks so much for joining us today.