Next, we're going to focus on ERCP and EUS, which are a subset of advanced endoscopy. So there are a couple of procedures within that larger umbrella of advanced endoscopy. I have no disclosures. So the objectives of this talk are to define ERCP and EUS, to learn the indications, contraindications, and pre-procedure preparation, including informed consent, to describe the components of ERCP and EUS procedures, both from the diagnostic and therapeutic standpoint, because these two procedures are used both to diagnose and treat disease, to determine the best practices for post-procedure care for ERCP and EUS procedures, and to discuss the components of proper post-procedure follow-up for ERCP and for EUS. Let's start with a couple of polling questions. Which of the following tests is most appropriate for evaluation of a patient with a low suspicion for choledocholithiasis, which, of course, is bile duct stones? Is it, number one, ERCP, two, ultrasound, three, MRCP, four, abdominal CT? Only one is correct. Okay. So I understand why one would have chosen ultrasound. And that would actually be correct if we were talking about gallbladder stones, which is chololithiasis. Choledocholithiasis is bile duct stones. And while ultrasound has a high sensitivity, which is to say a good pickup rate for gallbladder stones, it isn't all that good for finding bile duct stones. Here, the sensitivity is about 25%, which isn't that great. MRCP, which is an MRI that's reconstructed and protocol to look at the bile duct and the pancreas duct, actually has a high sensitivity for bile duct stones and is non-invasive and therefore much lower risk than an ERCP, which is an invasive test, and has a higher pickup rate for bile duct stones than abdominal CT, which is about as poor as transabdominal ultrasound is at finding stones. Now, endoscopic ultrasound has a high pickup rate for bile duct stones. But here, we're talking about just plain old ultrasound, which is transabdominal ultrasound. So the answer here is number three. ERCP adverse events include pancreatitis, bleeding, perforation, hypoxia, or all of the above. Remember what Dr. Call said about test taking here. Excellent. But for those of you who chose pancreatitis, that is the, frankly, most commonly seen true procedural complication for ERCP. So I want to underscore that. So I know you're thinking about it. EUS is used for diagnosis and staging of pancreatic cancer, endoscopic necrosectomy and pseudocyst drainage, FNA of mediastinal lymphadenopathy, evaluation of common bile duct dilatation, or is it all of the above? Yep. And of course, it's all of the above. And this is a good question, particularly because it reminds you that EUS is useful not only for diseases of the gut, but for all sorts of chest indications, because you can actually reach those areas. All right. The informed consent process does not always include a discussion about procedure indication, a discussion of procedure-related risks, the written signature of the patient undergoing the procedure, and opportunity for the patient or patient's guardian, parent, power of attorney to ask questions. All right. And this harkens back to my earlier talk, but is particularly important in therapeutic endoscopy. You need to have pretty specific discussions with the patient in your consent process, as we discussed. However, the patient isn't always going to be able to provide a written signature, right? They may be injured, they may be unconscious, it may be an emergency situation, or they may actually be a patient who has a power of attorney. So these are some caveats to remember. So it's not always going to be a written signature for various reasons. So what is ERCP? Well, it stands for endoscopic retrograde cholangiopancreatography, because you're using an endoscope to inject dye from down to up, which is what makes it retrograde in the bile duct and the pancreatic duct, which is what the cholangiopancreaticography is all about. So it's a way to image, diagnose, and importantly, treat conditions of the bile and pancreas ducts. Now, Dr. Kahl and others have mentioned that for purely diagnostic purposes, ERCP has been supplanted by other less invasive or non-invasive modalities, which is frankly really good, because going into an ERCP, most of the time we're going in to treat something. And when we go in to treat, we're not going in blind. There are frequently other imaging studies that have been done to give us a roadmap so that we're not taking a road trip to unknown territories without a map. So that's all a good thing. ERCP is particularly interesting because it combines endoscopy with fluoroscopy, which is live x-ray imaging. Very exciting. It uses water-soluble x-ray contrast, which we inject carefully into the ducts to produce an image, and based on that image, in the same sitting, we're going to diagnose and frequently treat the problems that we see. We use a dedicated scope called a duodenoscope and also a live x-ray machine called a fluoroscope, which is exactly the same machine that they use in interventional radiology to perform angiography and other procedures. Think about it. Your body's basically like your house. You're full of pipes, clean water pipes, dirty water pipes, hot and cold. And when you think about it, a pancreas duct is about the same size as a coronary artery. So why would the x-ray machine used to view and treat it be any different? This platform is more robust in biliary procedures than in pancreatic disorders. So we do a lot more biliary therapeutic ERCP than we do pancreatic. But when called for, we have many useful things we can do in the pancreas too. And these days, ERCP is often combined with EUS and interventional radiology to perform tag team or rendezvous procedures. So a lot's been going on over the past 54 years. 1968, were you even around? And if you were, what were you doing? These are the sorts of things that were going on in 1968. And what importantly was going on then also was that ERCP was being born. First described in 1968 by an obstetrical surgeon, go figure out what they were doing. Although, as you know, pregnancy is a major risk factor for gallstones, right? So maybe it had something to do with that. But the scope looked nothing like what we use today, but was actually this flexible esophagus and stomach scope that interestingly was manufactured on Clyburn Avenue in Chicago that they used to do the first ERCP. And the early years of ERCP actually looked like this, tube TVs and the whole part. This is actually Jack Venice at the Minneapolis VA working with an early fiber optic duodenoscope in the early 70s with his team. Even the lead aprons look different back then. Here's your dial telephone. And here is the processor for the endoscope. Really something else, right? The ERCP became way better when it became a therapeutic procedure, which is what we mainly know it as today. And that was when sphincterotomy was introduced just six years after ERCP was first written about, namely in 1974. And even more interesting was that endoscopic sphincterotomy at ERCP was described during the same year by both a group in Japan and a group in Germany, the Japanese group published in the ASGE journal in English, the German group published in a German journal in the German language, but both in the same year. So bright minds think alike. And you can see the homemade needle knife that was used to perform that sphincterotomy. Of course, there were no commercially available products of this nature at the time, so they did what they could in the garage and hammered that out. And here are some early images. Obviously, x-ray wasn't as good back then either, so the images look fuzzy to you. There was no digital fluorography back then, but there certainly is now, thankfully. But even then, you could see that stone down here in the ampullary outlet blocking the bile duct and the pancreatic duct, and they cut their way in with this homemade needle knife, opened up the papilla, and then extracted the stone. It didn't come easily back then. This is another Jack Venice picture at the Minneapolis VA, where they did so much early ERCP work in a legendary way back in the early 70s. So we've come a long way. Conceptually, this is what it looks like. This is a side-viewing scope, so the visualization that you're getting is more like the vision you get, the view that you get sitting as a passenger in a subway looking at the walls, so you can see the advertisements on the wall of the tube really well, which the train driver probably can't see as well because they can see the tracks looking forward, which you can't. So with a colonoscope or an upper GI endoscope, you're looking forward and getting the train driver's view. Here, you're getting the passenger view. Why? Because the business, the papilla that you're going to be cannulating and working on, is on the sidewall, the medial sidewall of the duodenum. So you need a scope that looks and points the device as you put down the scope, directed towards the side of the duodenum, not straight down. And getting this sideway view, you can get in the bile duct, place stents, take stones out, and do all sorts of things. So looking at ERCP indications from a conceptual point of view, we're performing cholangiography and pancreatography. We may be performing ductal tissue acquisition. We may be performing procedures to get rid of obstructions, strictures, stones, otherwise in those duct systems. And we may be mitigating leaks that can occur in the bile duct and the pancreas duct. Specific clinical applications then include stone disease in the duct, sometimes even in the gallbladder, malignant biliary obstruction from pancreatic cancer, putting a squeeze from the outside on the bile duct, or bile duct cancer itself, cholangiocarcinoma, or other masses that are putting a squeeze on the bile duct, such as liver masses putting a squeeze on the intrahepatic ducts. We may be dealing with post-surgical leaks after liver resection, after a gallbladder is removed, after a liver transplant, etc. We may be dealing with benign biliary strictures, trying to find out what they are from, whether they're precancerous or not, or dealing with any sorts of treatment necessary to resolve benign biliary strictures, usually resulting from surgery or radiation therapy, or even chemotherapy sometimes. Or we may be treating chronic pancreatitis, which leads to pancreatic duct stones, pancreas duct strictures, or chronic pancreatitis inflammatory masses causing extrinsic compression of the bile duct, and therefore biliary strictures. And of course, we treat pancreatic duct injuries and leaks via ERCP as well. So it's important to remember your biliary anatomy, so you can refer back to these pictures in G.I. Leap. Remember, the terminology is such that the main bile duct, the tree trunk of the bile duct downstream from where the cystic duct inserts is the common bile duct. That part between the cystic duct insertion and the hyalur bifurcation or confluence is called the common hepatic duct. The entire extrahepatic bile duct is sometimes simply referred to as the common duct or the main bile duct or the extrahepatic bile duct. The duct that connects the common duct to the gallbladder is the cystic duct, and then you have the left and right main hepatic ducts, and then the right and left intrahepatic ducts upstream from there. And here is the pancreas anatomy included with that. This is a busy intersection in humans and in opossums, but not in other mammals. We're the two types of mammals that have a joint pancreatic-obiliary union. And both the bile duct and the pancreas duct empty their contents out through the papilla of water into the second portion of the duodenum, the pancreas secreting bicarbonate and digestive enzymes and the bile duct secreting bile. And so this is why if you have an ampullary-level obstruction, say from a bile duct stone that's impacted there or from a neoplasm there, you can actually obstruct both the bile duct and the pancreatic duct and have symptoms in both organs. That is unique to humans and opossums. So there is a picture of a tumor here blocking the bile duct, leading to obstruction of outflow of bile. This can also obstruct outflow from the gallbladder, which is attached, which can cause pain in the bile duct, particularly if inflammation and infection set in because naturally occurring bacteria that are always getting up into the bile duct get up there but then suddenly can't leave and then grow unchecked and can result in infection. Typical symptoms and biliary obstruction then can include jaundice from the bile not being able to escape the biliary system and that all backing up into the blood. It can cause pain from the stone being impacted there and the refluxation of bile into the pancreas duct or the outflow obstruction to the pancreatic duct can result in obstructive pancreatitis known as gallstone pancreatitis. Those are some of the symptoms that can occur. And here is a duodenoscope traversing the esophagus and stomach into the duodenum to the level of the major papilla where we do our work under both endoscopic and fluoroscopic guidance, including things like placing stents, not even just into the pancreas or into the bile ducts, but also sometimes through the cystic duct into the gallbladder. So the way this is organized is that there is a fluoroscope with a fluoroscopy table, which is that live x-ray equipment that I was referring to. The patient lies on the x-ray table. The x-ray comes from a radiation source underneath the patient, then is beamed through the patient to an electronic detector, which then goes to an image processor, which converts that electronic information to an image that you can see on an x-ray monitor. And then the scope being down the hatch at the level of the papilla gives you an endoscopic view on a second separate monitor. So we're always looking at two monitors. And generally, this procedure, for a number of anatomic reasons, is preferred to be done usually in a semi-prone position, usually 30 to 45 degrees left lateral oblique. And here's some artwork to show you what the scope position and the end of the scope look like. So it's a little bit different scope from an upper GI endoscope because it looks and works to the side of the intestine, but the controls themselves are the same with the addition of a thumb trigger, which raises an elevator up and down to bring the device from being in a straightforward position up into the field of view and pointing it towards the major papilla. And here is a modern day common fluoroscopy machine that we would use in ERCP. So here is what the elevator would look like in action. It raises the device that you're working with up into the visual field, which is then also directed towards the papilla. And much as with upper endoscopy, we have a suite of devices that we can put through this accessory channel, including guide wires, different catheters, devices to extract things from the bile duct, including baskets and balloons, things to crush stones, lithotripters, stents, tissue acquisition items like forceps, brushes, needles, et cetera, and even a miniature scope called a cholangioscope that you can actually put through this accessory channel and see endoscopically right up the duct, and I'll show you that in a few minutes. So there are various types of cannulas or just straight catheters for injecting contrast into the biliary tree. Sphincteratomes have a small monopolar cutting wire, which is used for two things. It's strung up almost like a violin bow, so that if the procedure nurse tightens up on that wire, it bows the wire with an excursion away from the catheter. And this does two things. It gives you another plane of control of the device to lift it up into a biliary angle to facilitate cannulation of the bile duct specifically. And because it's monopolar, you can add cut and coagulation current to this wire to cut the sphincter muscle at the papilla to open it up to allow you to perform various therapies through a larger opening, because that tiny native opening of the papilla is only about as big as the opening at the bottom of your ballpoint pen. We use different types of guide wires and different diameters and lengths through the scope for different applications. Choledocholithiasis means bile duct stones. And so here you're seeing the artist's conception of what an impacted bile duct stone can look like, blocking the pancreas and the bile duct and putting an extraction balloon in after a sphincterotomy to remove that stone. And here's what a cholangiogram looks like with what we call filling defects, which are floating in a live fluoroscopic endoscopy. You can actually see these moving around as you inject the dye. Here's what a sphincterotomy looks like in the process of performing one and when we're done with one. And this is what it actually looks like in a short video clip. Here I'm performing one, going right up and bisecting the impression of the bile duct on the duodenum and taking that incision to make it big enough to remove a stone. Just like that. Right sizing it for the size of stone. Here's another sphincterotomy. We've already started it and now we're extending it a little bit further for a larger stone. And as you can see, as you cut that muscle, the configuration of that tissue changes and so I alter my scope position to continue that cut. And this is just a picture of a stone coming out after the incision has been made and the stone is extracted. We have a number of different types of tubes or stents that we can put in the bile duct to get across strictures. Or if there are stones that can't be removed in one sitting, we might advance the stent across the stones up above the stones to allow for drainage around them. And here's what it looks like when you place that guide wire up the bile duct and then advance the stent over that guide wire. And this is what it looks like in the end, providing biliary drainage. Usually to do this, this is a video if you can run it for me. We will, under fluoroscopic imaging, put a guide wire up the duct, followed up with the catheter, inject some dye to show us the duct that we want to see and then chase that contrast by spinning our guide wire to try to get it into the exact duct that we want to work in. Here, we are advancing the catheter to inject this specific duct here because we're ultimately going to want to stent that. So this is the fluoroscopic view. As you can see, once we're up the duct, our imaging is actually done by X-ray, not by endoscopy. And mind you, the nurse is actually handling that catheter and guide wire. So ERCPs are particularly fun and interesting because both the physician endoscopist and the technical nurse both have a technical role in performing the procedure. Lots of fun. And the patient truly benefits. This is a view of the stent endoscopically viewed going over that guide wire and stent guide right up that bile duct you just saw the nurse I'm working with and myself accessing that particular duct. And this is a long stent that has a bunch of side holes in it that we are putting up into that duct to drain this patient's bile duct, which was obstructed by a very large metastatic adrenal cancer that was metastasized to the liver and blocking the bile duct. And now the bile will flow, the patient's jaundice will go away and she'll be able to receive more chemotherapy, which couldn't be administered during bile duct blockage because the toxic metabolites of the chemotherapy are mainly gotten rid of through the body by getting it out through the bile. Now the exhaust pipe is placed and the patient can be treated again. I showed you earlier, we can even stent the gallbladder. And so here we're injecting contrast into the gallbladder, which has a very large stone and was infected because it was obstructed. We've put the wire in and we can put a stent right up that guide wire, the very same way I just showed you in the bile duct. So there it goes. Okay. And there's the endoscopic view. Remember, we're looking at both screens back and forth at the same time. We have two different monitors that are running at the same time. So these are stents that are being inserted right through the bile duct into the gallbladder. We not only have plastic stents, but we have self-expanding metal ones that are basically made out of wire. Looks like basically the screen that's outside the window of your house rolled up into a tube up to about a centimeter in size if you're putting it in for ERCP. And when you pull them and make them really skinny and put a cover on them, they're small enough to put through your scope. And then when you peel the cover off, when you have the stent in place, they expand in position. And some of them are bare metal and others are covered with a silicone or Teflon material, depending on whether you want them to be permanently embedded, or if you want to be able to remove them in the future. And here's what it looks like when it's going into a bile duct. And here's what it looks like when it is expanding once you have put it up the bile duct. And when you're done, it looks like that. The advantage of metal stents is that because they can expand bigger than the diameter when you put them in, big pipes have a tendency to stay open longer than small pipes. So you don't have to change them or revise them as often as the smaller diameter plastic stents, which can't expand. Now, plastic stents are often used in the pancreas as well. They come in different shapes and sizes. We have different balloons that we use to dilate strictures. We also have taps that we can screw across really tight strictures to then allow us to put balloons across and make them bigger. We also have pancreticobiliary, that is to say smaller versions of tapered plastic dilators. So these are basically pancreticobiliary, savory type dilators that can be pushed across strictures in the pancreas of the bile duct to stretch them as well. We have baskets that are very similar to urological stone baskets. They're modeled after them, which we can also use in the bile duct in concert with balloons. We have brushes, biopsy forceps, aspiration needles that can be used in the ducts as well. And as I mentioned earlier, we have a miniature scope called a cholangioscope that can be put over a guide wire into the bile duct or the pancreas duct. Here, I'm looking into a bile duct at a small impacted intrahepatic stone. And we have various miniature devices we can put through the cholangioscope, such as a forcep or a basket. Interesting image there. So the role of endoscopy in bile duct stones is for high-risk bile duct stones will sometimes go straight to ERCP if that stone is likelier than not to be there. So a bile duct stone that's seen on ultrasound CT or MR, the bilirubin is greater than four with a dilated bile duct on imaging, or if there's frankly ascending cholangitis, that's high risk and will generally go straight to ERCP. With lower risk like that case that I brought up for you at the beginning of this talk, there may be a rise in liver enzymes, but maybe they're already coming down. Dilated duct on ultrasound without anything else or acute biliary pancreatitis. You may wanna go in and do less invasive imaging, maybe non-invasive with an MR first, which is high sensitivity, but non-invasive. EUS, which is invasive and does require anesthesia, but is less invasive and lower risk than ERCP. Or perhaps go straight to cholecystectomy as the patient's gonna need a gallbladder removal with stone disease anyway, in which setting many surgeons can do an intraoperative cholangiogram. And if that intraoperative cholangiogram demonstrates no stone or just small stones that can be flushed out at surgery, the patient can avoid an endoscopic procedure like an ERCP altogether. Again, no pre-procedure assessment is always imperative for any endoscopy review. That risk assessment, the ASA classification, make a decision on what your sedation or anesthesia plan's gonna be. If the patient is DNR, DNI, you need to reverse that DNI order, particularly if you know going in you're gonna need to intubate the patient. Antibiotics are not needed for patients who you know you're gonna be able to attain complete biliary drainage at the end of the procedure. But if they've got PSC or they're post liver transplant, or they're likely for anatomic reasons to not achieve complete biliary drainage, then you better give them some pre-procedure and post-procedure antibiotics. And depending on your practice, either in all comers or in patients at higher risk for procedure-related pancreatitis, provide rectal NSAIDs, either endomethacin or diclofenac, whichever one your institution uses. Also manage your anticoagulation. Remember patients who have sphincterotomy are at high risk for bleeding. And so in those patients where you're gonna perform or are likely to perform sphincterotomy, hold their anticoagulation and antiplatelet agent. There's no standard recommendation for a particular INR, particular platelet count, but in most practices, you're going to want to have an INR of around 1.8 to two in order to do a sphincterotomy. And you're going to want to hold that for a couple of days because the risk of a sphincterotomy bleed is not just the day of the procedure, but it extends for a couple of days after that. If you're not performing a sphincterotomy or a dilation, diagnostic ERCP or the other things that you do like brushing or a sweep alone, or just a cholangiogram, a pancreatogram are low bleeding risk. So you can perform those on active anticoagulation and active antiplatelet agents. Informed consent is important. Review the procedure goals, personnel alternatives. We talked about these things. The main complications are procedure-related pancreatitis, about five to 10% perforations, less than 1%. Bleeding lower still. Remember cardiopulmonary risks and death. Those risks are real, even though the risks are low. And there's also the risk of the procedure being unsuccessful. Discuss all of these things with the patient. Remember to ask them if they have any questions. And importantly, don't forget them to ask if they're willing to receive blood products if necessary. Remember some people won't or can't receive blood products for personal or religious reasons or otherwise. You want to know before you start. Post-procedure management is equally important. They can start clear liquids when they're recovered from anesthesia. There is no consensus for diet advancement. Some physicians who perform ERCP don't want the patients to eat afterwards. But since there's no evidence basis for that recommendation, many of us tell them to start with clear liquids if they tolerate that, to eat light, solid. And then if they tolerate that, to go ahead and eat a regular diet. There's no right or wrong there. Ask those in your practice what the practice consensus is and go with that. Monitor for clinical response to the procedure goes without saying. And then arrange for proper follow-up, including removing or replacing stents. No pipes stay open in a dirty area like the bile duct or the pancreas duct. Remember there's lots of food and bacteria down there. So this isn't like coronary arteries. Let's shift gears to EUS endoscopic ultrasound. This technique is for diagnosis and staging and management of a broad range of not only GI, but also non-GI disorders, particularly in the approachable lower GI tract and the approachable thoracic area. Unlike ERCP, the number of cases of EUS performed have steadily increased over the last couple of decades. And this combines endoscopy with high frequency ultrasonography. So this is basically an endoscope that actually has an ultrasound built into the tip. Just fascinating. And there are two iterations of this. One variant is a radial endoscope where you get an ultrasound image where the ultrasound machine is seeing in 360 degrees. But there's also a linear endoscope where you're getting an image that is in the axis of the organ that you're looking at. Now, of course, you can get a radial image by torquing this scope around, but in any one scope position, you're seeing along this axis. The advantage here is that any device, including an aspiration or biopsy needle that you put out of the accessory channel is actually seen by your ultrasound images. So you can do tissue acquisition and all sorts of treatments with this type of scope. So a linear echo endoscope is a very powerful endoscope indeed, probably the most powerful endoscope in our entire armamentarium. This is a little cartoon of the different layers that you can see. Feel free to read this a few times on GI Leap. Happy to go over it if you have questions, but in the interest of time, I'm gonna keep plowing through. The indications are diagnosis, staging, and therapies. Diagnosis includes not only pancreatic solid and cystic lesions, but subepithelial lesions in the wall of the gut, mediastinal masses and lymph nodes, liver masses, thickened gastric folds, bile duct dilatation, bile duct stones, which we talked about a few minutes ago. In staging of esophageal cancer, gastric cancer, pancreas and lung cancer, ampullary cancer, rectal cancer, very strong staging device. And for invasive diagnostic, that is to say biopsies. And then therapies are growing all the time. Therapeutic indications for EUS and tag team EUS with ERCP, including not only pseudocyst drainage, but getting rid of necrotic pancreas tissue. That's actually done via an EUS technique, often mitigating the need for a huge surgery. Really remarkable. Bile duct and gallbladder drainage can be done all the time with therapeutic EUS. Nerve blocks in the celiac plexus and elsewhere, glue or coil embolization of varices, something that used to only be done in interventional radiology, now done with EUS. And EUS guided ERCP where EUS is used to throw a line to perform ERCP where ducts can't be accessed with ERCP alone. Lots of things that you can see well with EUS, including stones in both the bile and pancreas duct, frankly. And not only can you see pancreas masses, because with a linear echo endoscope, you can actually see in your echo image, the needle, you can drive the needle right through the tumor that you're seeing and very, very safely get tissue, avoiding vessels that you might otherwise puncture accidentally. Again, as with every procedure, pre-procedural assessment is very important and is exactly the same. Remember to prescribe antibiotics if you're needling a mediastinal cystic lesion or performing therapeutic EUS procedures, you need to manage antithrombotics in invasive EUS, but otherwise it's essentially the same as other therapeutic endoscopy. And so again, the same point that I made earlier about anticoagulants and antiplatelet agents. Informed consent is exactly the same as it is in other endoscopic procedures. So practice, PEARLS, ERCP and EUS are essential procedures for the management of GI and frankly, some non-GI diseases. Appropriate patient selection, that was extremely important, especially in therapeutic procedures. Less invasive and lower risk tests should be chosen where that's possible. Pre-procedure management of antithrombotics and operative risk is the key to success and to avoiding adverse events because you'd rather avoid adverse events than to actually manage them, right? And when complications do occur though, early recognition and prompt and expert management are essential to successful management. Thank you very much.

ERCP

EUS

endoscopic retrograde cholangiopancreatography

high-frequency ultrasonography

patient selection

complications management

pre-procedure preparation

post-procedure care