We want to kind of move away from the pancreas and talk about endohepatology, new frontiers for the gastroenterology, although I will argue that we've been bending varices for quite a few decades, so the frontier is not new, but we are definitely expanding it, and David Dill has been on the forefront of that expansion. David. Thank you. Thanks to everyone, and thanks to you all for inviting me to do this. My disclosures. So endohepatology, one way of defining it is the emergence of endoscopic techniques that can be used for diagnosis and treatment of liver diseases. As we know, originally it was all EGD-based, looking for varices, banding varices, injecting them. ERCP then was the next important advancement, and now most of the advancements in the field of endohepatology are EOS-based. For further information, there is this multiple review papers in TIGE, so I refer you to those journals for an up-to-date review of the subject. And the reason endohepatology is even so important these days is obvious. It has to do with the obesity epidemic in this country, and the increased incidence of liver disease related to NASH, as you can see, as a rising cause of the need for a liver transplant. So the common current applications of endohepatology, of course EGD for a salvageal variceal diagnosis and management, EOS for evaluation of gallbladder and the biliary tree. And then I would submit that EOS-guided liver biopsy has been around long enough, and it's become one of the cornerstone methods in endohepatology. Emerging applications are EOS-guided shear wave elastography, EOS-guided portal pressure gradient assessment, EOS-assisted gastric variceal treatment, and then EOS-guided gallbladder drainage. And one of the goals of endohepatology is to provide a one-stop shop for evaluation of liver disease, where with an EOS scope one can, EGD and EOS scope, one can do a full assessment, not necessarily having to send the patient to interventional radiology. So as, you know, we have a very close working relationship with IR, always have, and with hepatology. And as endohepatology grows, what I see is the areas of overlap, we'll have more overlap with our hepatologists, and IR is going to get cut out of the business a little bit where, you know, we used to send them cases for liver biopsy, we used to send them cases for portal pressure assessment, and those are staying within interventional endoscopy now. The first part I want to touch on is EOS-guided liver biopsy. It's been around for a little while. The first case was from Wurselman and Levy, where they were using a Trucut needle, which was not a very good needle, but that was the first reported case of EOS-guided liver biopsy that I could find in literature. My colleague from Penn State, Abraham Matthew, wrote up a couple cases where he used that same needle to get biopsies, and I think really the landmark paper for me was Stavros's paper where he used just a plain 19-gauge needle, and he had adequate specimens in 20 out of 22 cases, and I had such trouble using the Trucut needle before this. After I read that paper, it really changed everything for me, and I led a multicenter study, and it showed very high specimen adequacy. We looked at tissue yields, and this is one area where there was initially a lot of pushback from hepatologists and sometimes pathologists, and what we found was that EOS-guided biopsy was comparable or better than percutaneous or transjugular liver biopsies in terms of portal triad counts and total specimen length. In this study that we did, this even predates an FNB needle. This was just with a regular 19-gauge FNA needle, and if we were to redo this study, it would greatly exceed both transjugular biopsy and percutaneous. Dispecimens we get are typically beautiful. You can great portal anatomy, and this is actually one of my favorite slides. This is a cirrhotic liver, and you can see all these cirrhotic nodules, and with a FNB needle, one can get very long cores that give adequate diagnosis for even advanced cirrhosis. There are several advantages of EOS-guided liver biopsy. First of all, if the patient needs an EGD, an EOS, even a colonoscopy, we can do in addition to the liver biopsy, we can do it all at the same time, which is very cost-saving and saves a lot of trouble for the patient. The yields, as I mentioned, are outstanding. The safety profile is outstanding. It's possible to do bilobar sampling, which is not generally, it's hard to do outside the IR suite. Certainly it's an improved patient experience with less anxiety, and it keeps the care within the GI department. Through several studies, we've been able to tune up the technique, and we found a few things. One, wet suction, which I'm going to show a demonstration of, is better than dry suction. A 19-gauge FNB needle is better than a 19-gauge FNA needle. One pass with three actuations is better than one in one. The 19-gauge FNB needle is better than a 22-gauge FNB needle. And if for the diagnosis of naphaldy, bilobar biopsy is better than unilobar. As far... I will talk about the technique a little bit. As I mentioned, one can use an FNA needle for this, as well as an FNB needle. Both generally are better with FNB. This is the wet suction I'm talking about, and this seems to be one of the most critical parts about getting the best yield. For wet suction, one pulls this dilate, and we use a heparin flush, and that just prevents clotting of blood in the needle. So we flush heparin through until there are a few drops of fluid, then we put a little bit of fluid in the syringe and cock the syringe, and so we are using full suction for this. And now the needle is ready for use. It's very important, I can't say this enough, confirm that you're looking at the liver. So here's the liver, there's the spleen, and you can see the echo texture is exactly the same. In fact, the spleen is even a bigger target. So there have been complications reported of inadvertent splenic puncture. So with a radial scope, it makes the point even more. You can see the liver on the left and the spleen on the right, and both very large structures. So just double check, if you're biopsying the left lobe, that you're looking at the liver and not the spleen, very important. We find a trajectory without intervening vessels, and it can be three centimeters, doesn't have to be full eight centimeters, here at three or four and a half. And one stick and three to-and-fros is what we found to be perfectly adequate, and it doesn't have to be fast. You can see that needle is traveling at a very reasonable pace, we don't have to jab it like you're sticking something. This is how to look at the right lobe. You typically transduodenal. And in this case, sometimes it's... We love to see the needle, of course. Sometimes in a hyperechoic liver like this, it's hard to see the needle tip, and you can see... You don't see exactly the needle, you can sort of see tissue moving. But the longer you can go with the needle, the longer the cores tend to be. We use the micro-sieve method, so if you've heparinized the needle, then the blood will not clot. And we take all the contents of the needle, put it in this sieve. And don't forget that if there's any blood in the syringe or in the stopcocks, your liver biopsy may be there. So don't overlook tissue that could be present in other parts of the system. Put those in there, and then we actually wash the specimen right away, and this way we can assess adequacy right on the spot and know we're good, we have a great specimen, or perhaps we have to do another pass. It also minimizes tissue handling. So you don't want to handle these specimens excessively. And you can see very nice specimen lengths. And I refer you to this top tips piece that I wrote recently that summarizes the approach to doing U.S. liver biopsy. Next I want to move on to U.S.-guided portal pressure measurement. So this system basically, it's a regular 25-gauge needle with a manometer on it. It got FDA clearance fairly recently, 2020. COVID, I think, put a little bit of a damper on rollout of it. So it's still early days as far as this being done. But the proposal is it be used instead of transjugular portal pressure measurements. And basically what we're doing is taking this 25-gauge needle, heparinized needle, going through liver parenchyma into a branch of a hepatic vein and a branch of a portal vein. And then we get pressure measurements. Advantages, again, it avoids a transjugular approach, so more acceptable patients. Again, it unifies care of our liver patients, keeps them within the GI department. And we can do an EGD, U.S. liver biopsy all at the same time. And adverse effects are quite rare. The indications, similar to indications for transjugular portal pressure measurement, really. When you Doppler these vessels, you get a different Doppler signal, a biphasic or triphasic signal if you're in a branch of the hepatic vein. And a monophasic if you're in a branch of the portal vein. And really the key to safety is to go through a parenchyma to get to the vessel. So you can see the needles going through a fair amount of parenchyma to get to the vessel. And that provides a safety margin. And with a 25-gauge needle, complications are very uncommon. There you can see how much liver the needle's going through and going right into a branch of the hepatic vein. It's courtesy of the UC Irvine group. And here they're going for a branch of a portal vein. Get measurements with this manometer. We typically get a series of three measurements, average them, and you can calculate a portal pressure gradient in a very straightforward way. You're familiar with, of course, with charts like this. I think the one thing that this allows is we can look at this, certainly not the florid portal hypertension people with varices, but this group here, like the 5 to 10 millimeters of mercury gradient. And maybe we can learn new things about this group. And it can even be used, since it's fairly easy to do, if one was going to institute a treatment, a new pharmaceutical treatment for portal hypertension, one can easily measure the effect by repeating this. These are some early studies that Ken Chang and his group did. This is in a pig model where they did simultaneous EOS-guided portal pressure measurements as well as transjugular and found very good correlation. So that was the initial. And then they followed up with a study looking at patients with various clinical categories of portal hypertension and found correspondence of the portal pressure gradient with clinical subgroups. So again, very early, very few papers have been published to date on it, but I expect to see great expansion with EOS-guided portal pressure measurement. The next area of endohepatology is management of gastric varices with EOS-guided glue injection and coiling. What we're talking about here really are the GOV1s and IGV1s. GOV1s typically can be managed with banding, but GOV2s, not well managed with banding. The term that's been used is endoscopic variceal obturation. And obturation means filling the varix with like glue or coils or both. And really, if you think about your own practice, it all depends on if you have someone who is willing and able to do this EOS-guided gastric variceal management, which is, let's face it, not very widespread. There are some centers that people relish doing this, and places that don't, we do rely on IR with their expertise with TIPS placement. Now one can do endoscopic glue injection as well, and there are a lot of experts who feel very comfortable with that. The downside is pulmonary embolization of the glue or embolization to other structures such as the brain. So what people have come to is EOS-guided glue plus coil injection. So the coils, we get these from the IR department. They have kind of like a furry coating, and that promotes thrombosis of the varix. So use of coils in addition to glue decreases the incidence of glue embolization. This video is from Ken VanMuller's group showing a large IGV1. So, these are usually treated with a 19-gauge needle. It's a very steady hand, obviously. And here they're pushing the coil through the needle, and it coils in the lumen of the vein. And it can take more than one coil in some cases, spinning around in that vein, as you can see. And that's followed by a glue injection. Some groups have been using gel foam injection. And this is basically the procedure, the U.S.-guided variceal buteration. So, really, the limitations are it requires an experienced endosynographer. In the acute setting, like, you know, in the middle of the night, it's limited availability, of course. Some groups are described looking for a single perforator vessel versus a complex variceal lake. So, it's in these very large lakes where you go down within the U.S. and there's no single perforator, it may need to be combined with an IR-type procedure. And glue embolization is possible. With the coils, it seems to reduce that. But checking for a PFO may be advised. Finally, I will claim it was guided gallbladder drainage under endohepatology, and I noticed it wasn't anywhere else in the program, so I put it here. This was first described by Lee in 2007 using plastic stents, and it's currently done with cautery-enhanced lumen-opposing metal stents. The technical success is very high, approximating 100%. Clinical success, also very high. Adverse effects, 10 to 20%, which also includes foot impaction and migration. Recurrent cholecystitis in 2 to 5%. In general, transduodenal stent position is favored to transgastric. We are seeing a lot of referrals from surgeons at our institution for this, and surgically unfit patients for various reasons, very elderly, dementia, other comorbidity. Patients with cirrhosis who need management of acute cholecystitis. And also people who might have had a percutaneous cholecystostomy done emergently, and these are non-surgical candidates who want that internalized. So this is an overview of the procedure. Through the duodenal bulb, hopefully we find a good target. So here you can see a nice gallbladder target, a lot of stones and sludge within. And in the usual fashion, we use the cautery-enhanced lamps to deploy the inner flange within the gallbladder lumen. And the luminal flange, of course, will end up in the duodenum. Very often we will post-dilate this dent. So there remains many unanswered questions about U.S.-guided gallbladder drainage. How long should the stents remain in place? This is not known. Similar to what Sam was talking about, these stents probably should not be left in indefinitely, and they can be exchanged for double pigtail plastic stents. Is there a need to place a double pigtail stent within the lambs? Not clearly known at this point. Is there a preferred lamb's diameter for doing these? And what about lap colostectomy after gallbladder lambs? Some, if you talk to surgeons, they'll say it's definitely harder, but there's at least one paper in literature that says that it did not interfere with doing surgery afterwards. So finally, the key takeaways about endohepatology. The future of endohepatology is as bright as awareness and usage expands. It can allow a one-stop-shop approach to diagnosis of liver diseases. U.S.-guided liver biopsy is equivalent or better than percutaneous liver biopsy. U.S.-guided portal pressure gradient measurement may replace transjugular route in most cases. And finally, we are seeing more referrals for U.S.-guided gallbladder drainage, particularly from surgeons. Thank you.

endohepatology

endoscopic techniques

liver diseases

obesity

liver transplants

varices