Good afternoon, and let's proceed to talk a little bit more about ERCP, which Dr. Call was just talking about, and on EUS, too. All right, so the objectives are to define ERCP and EUS, learn the indications, contraindications, and pre-procedure preparation, including, of course, as we talked about before, informed consent. Describe the components of both of these procedures, diagnostic and therapeutic, because both of these procedures are used in both of these goals. And determine the best practices for post-procedure care for ERCP and EUS patients, and to discuss the components of proper post-procedure follow-up for ERCP and EUS, because as we said before, procedures are not stand-alones. They only have relevance in the context of the overall care of the patient. So let's start with a polling question. Which of the following tests is most appropriate for evaluation of a patient with a low suspicion for bile duct stones? If a patient has a low suspicion for bile duct stones, which of these four is the most appropriate test? Is it ERCP, transabdominal ultrasound, MRCP, or abdominal CT? You want a low-risk test that's comparatively inexpensive, that has a high pickup rate for bile duct stones. Which one of these is it? Yes, you're a very smart group. That's right. ERCP, as Dr. Call just explained, is an invasive procedure with real procedural risks. You don't want to be using that to look for a bile duct stone. You might to take one out. We'll talk about that in a minute. Transabdominal ultrasound is an inexpensive test with essentially no risk, but while it has high sensitivity for gallbladder stones, it has comparatively low sensitivity and therefore a low pickup rate for bile duct stones. MRCP, which is an MRI tuned to look at the bile duct, protocoled that way, is low risk. You can even do it without IV contrast, but it has high sensitivity for bile duct stones. Abdominal CT has a comparatively lower likelihood of finding bile duct stones. It really would require contrast to show you much. Most bile duct stones are cholesterol stones, which are radiolucent and not radiopaque and therefore not well imaged by CT. So the best answer there for low suspicion of stones, you want something with a high pickup rate that's noninvasive, that would be an MRCP. ERCP adverse events include, Dr. Call just talked about this, pancreatitis, bleeding, perforation, hypoxia, all of the above. Excellent. Yes, all of the above. Pancreatitis has a, that risk is about five to 20% depending on what you're doing. So it's far from a small risk. Need to design a question next time where all of the above is the wrong answer. Okay. EUS is used for diagnosis and staging of pancreas cancer, endoscopic necrosectomy, and pseudocyst range, FNA of mediastinal lymphadenopathy, anastomosis creation with lumen opposing stents, all of the above. Yes, you got it. What started out as a solely diagnostic procedure, these days is a powerful therapeutic modality for treating patients with disease, as well as diagnosis and staging. Excellent. Okay, let's start with ERCP, which is the older test that's been around for over 50 years. And this is endoscopic retrograde cholangiopancreatography. It's endoscopic because it uses a scope. It's retrograde because you're injecting dye against the natural flow of bile from top to bottom. You're injecting from bottom to top. So it's retrograde. It is a cholangiogram because you're imaging the bile duct, and it might also be a pancreatogram because you're possibly imaging the pancreatic duct. We only do that either incidentally when we don't mean to, but get in the pancreas because it's easier to get in that direction, so inadvertently, or we do it if we're actually interested in looking at or treating the pancreas. So sometimes you will hear the term ERC batted around because they're only doing a cholangiogram or an ERP if just a pancreatogram is being done and the bile duct is ignored because it's not important in the context of what's going on with the patient. This, of course, is, as Dr. Kahl mentioned, a way not only to image, diagnose, but also more and more these days actually to treat conditions of the bile duct and pancreas, although we do use it frequently diagnostically still for tissue acquisition in disorders where there are bile duct strictures like primary sclerosing cholangitis or situations where we suspect a malignant stricture. This, of course, combines endoscopy with X-ray, live X-ray imaging, which we call fluoroscopy, and the ERCP team actually reads that fluoroscopy live. We don't depend on a radiologist to do that. This utilizes water-soluble contrast that's actually injected through a catheter that's placed through the scope. That catheter is advanced into the duct, the contrast is injected, and then live X-ray or fluoroscopy is used to actually see the dye that's in the duct. It is actually the contrast contour that you're seeing, not the actual duct tissue itself, unless you are doing a scope and scope, which I'll mention later. Imaging diagnosis and treatment is generally under radiologic rather than endoscopic guidance. This uses a dedicated scope made for ERCP. It has a lens on its side. It's called a duodenoscope. The fluoroscope that we use is identical to what interventional radiology has. These are really not fluoroscopes that are expressly made for ERCP. They're made for angiography, and we use them, which makes sense because a bile duct is a vessel. It just carries bile instead of blood. Some of the smaller bile ducts are the size of a coronary artery. Of course, the device that's used to image a coronary artery would work for us just fine, and that's exactly what we have. The platform is actually more robust in dealing with biliary issues than pancreatic disorders. EUS is king when it comes to the pancreas. ERCP, though, is combined with EUS and tag-teamed with IR in meeting out some therapies. As I was mentioning, ERCP is over 50 years old. It was first described by an OB-GYN, believe it or not, in a surgical journal in 1968. The original device was this thing that you see in the bottom left that was manufactured by a company in Chicago and ultimately morphed into the early fiber optic device that had an eyepiece that you had to peer into that you see to your right. Here's a historical picture. That's Jack Venice, who was at the Minneapolis VA Medical Center and was on faculty at the University of Minnesota. He was one of the first Americans to go to Japan to train on ERCP, bring the equipment back to the United States, and apply it here. You can see the TVs, literally, the CRT tube televisions that are being used as monitors. He is sitting down to do the procedure, which is how endoscopy used to be done. He passed away over a decade ago and was quite a pioneer. ERCP became way better and entered the therapeutic world when sphincterotomy was first described, ironically, on opposite faces of the earth. Keiichi Kawai described it in the ASGE journal, Gastrointestinal Endoscopy, in 1974. In that same year, Meinhard Klassen described in the German literature exactly the same thing. This, of course, was able to open up the major papilla, cut through the muscle there, and allow us to enter the bile duct to not only opacify it with contrast under fluoroscopy, but also to start doing things to treat, such as removing stones. What you see here is a basic device called a traction sphincterotome. If the procedure nurse applies traction to the tome, it bows up just like a violin bow, and that allows you to place it in the direction of the bile duct or the pancreas duct more selectively. Wire is usually used to navigate your way into the duct of choice, and then that wire is a diathermic wire, and it's used to cut the upper lip of the papilla right through the sphincter muscle and allow better access, entry, and removal of devices and foreign objects, such as stones in the bile duct. The scope can be used to place stents, as you see in the radiograph to the right. Any number of things. There are a number of indications for ERCP, whether that be in the bile duct or the pancreas. You might be going into acquired tissue when there's diagnostic tissue acquisition or brushing for cytology that's required. As a general theme, there may be some sort of an obstruction, whether that's an object like a stone that needs to be removed or a stricture or a tumor blocking the duct that requires dilation or stenting. And there may also be a leak of the bile duct, most commonly after liver or biliary surgery, such as a gallbladder removal. That can be mitigated without patching the leak, just by performing a sphincterotomy and placing a stent at the ampulla, at the papilla there, to reduce the gradient across the papilla. Once that gradient is lower than the gradient across the leak, the bile chooses to go through the stent instead of the leak, because that is the lower gradient of pressure and the leak will seal up typically within a few days. Very effective. The most common indication of ERCP when it comes to therapy, though, is bile duct stones. And this is done as described to you earlier, typically, at least in the United States, a sphincterotomy. So that incision with a hot wire will be performed and then a balloon or basket are both used to remove the stone. We also deal with malignant biliary obstructions. This is more frequently pancreatic cancer, but could be bile duct cancer or gallbladder cancer, or due to an intrahepatic or porta hepatis mass that's compressing the bile duct extrinsically. Any of those can be dealt with very effectively in almost all situations with endoscopic stenting. We talked about leaks, we talked about strictures, but there are also some that are benign due to some of these disease issues that I have enumerated here. Those can be dealt with typically by dilation and sometimes stenting as well. The choice of stent may be different, however, in a benign procedure or in a benign tumor. With chronic pancreatitis, patients develop intraductal stones in the pancreas duct, also strictures there. Sometimes there is swelling of the pancreatic head as a result of that inflammatory process that can cause extrinsic compression of the bile duct and poor biliary flow and obstruction and jaundice. Stenting can deal with that. Balloons and baskets and lithotripsy can remove pancreatic stones. Pancreatic leaks are dealt with pretty much the same way that bile duct leaks are often with stenting. I just put all of this up to remind you about biliary anatomy. The liver has, grossly speaking, two lobes. We think of the left system and the right system of the biliary tree corresponding to those lobes. The extra hepatic bile duct goes from the ampulla of vater up to the hepatic hilum where the left and right ducts flow into it. The common duct is then again subdivided between the common bile duct, which is the lower part of that tree trunk of the biliary tree that goes from the ampulla up to the cystic duct insertion, and then from the cystic duct insertion to the hilar bifurcation or confluence is called the common hepatic duct. Here is the bile duct in reference to the pancreatic duct. As you can see, the distal common bile duct is intrapancreatic in its location. That's why a tumor in the head of the pancreas can cause extrinsic compression and obstruction of the bile duct frequently treated through ERCP with stent placement. This is what a side-viewing duodenoscope, which is the ERCP scope, looks like when it's in use. This type of scope has a lens on the side rather than on the front of the scope, so that rather than getting the train driver's view in the subway, you actually get the passenger window view in the subway using this scope. Why? Because the major papilla, which is the target of all of our diagnosis and therapy, is on the sidewall of the second portion of the duodenum. In classic position, the patient is usually placed in a left lateral oblique position, often with a triangle wedge on their front side to tip them up a bit, and the scope is inserted. These days, most of these are done under general anesthesia in the United States. Where anesthesia is less available, it's still done with larger doses of moderate sedation. There is a device called an elevator you see at the bottom right there. Because the lens is on the side and the instrument channel goes directly in a perpendicular plane to the lens, there's a little ramp that's controlled with your left thumb trigger. When you push down on that lever, it lifts that device up into the view of that side viewing lens, which is also in the direction of the papilla. That's the elevator, and that is unique to scopes that are used to access that area of the anatomy. Of course, just as important as the scope is the fluoroscope we talked about before. That is a typical fixed C-arm angio machine. That's actually the device that we have in our units, and that is identical to the device that interventional radiology in the room next to mine uses to perform their angio procedures, typically in vessels that carry blood instead of bile and pancreas juice. We mentioned the elevator before. Here's a picture of an elevator bringing a guide wire into the proper papilla-oriented position. Other devices that go through the scope over the elevator and into the papilla and the ducts are listed for you here. You see to the right a cholangiogram, which is where the catheter device cannula or papillotome here is advanced through the papilla into the bile duct used to inject contrast. Where the stones are that you see there, there is less or no contrast, because the stones displace the contrast. Therefore, you can see them very, very clearly lined up. Here you would perform a sphincterotomy and then use an extraction balloon or basket to remove them. This is a sphincterotomy that's being made with a monopolar traction sphincterotome. That's the proper name of the device. You can see that being used here on this video. This is typically cut almost or completely flush to the duodenal wall. If you cut it farther than that, you would actually perforate into the retroperitoneum, so we avoid that. That's a sphincterotomy. Here's another one being performed in a slightly different orientation. And the most common indication for that is stone extraction. If you can start that video for me, Sam. For some reason, it's not coming up. There we go. Thank you, sir. And you can already see the stone crowning there as we're putting traction on it. Larger stones don't necessarily need an extension of that sphincterotomy. You just need some patience. The tissue will accommodate after a while. It'll start to stretch if you give it time. And so you're seeing constant traction is being applied with a balloon catheter. And that stone just popped out. And not to belabor it, but there are multiple others, as you saw in that cholangiogram before. But every one of those is then taken out one by one through the duct. Most endoscopists will tell you that that is most satisfying. A lot of stents are made out of plastic polyethylene or polyurethane and other PTFE-type fluorinated hydrocarbon materials. They come in different shapes. Most of these things, like side flaps and pigtails, are there to keep the stent from migrating. They're anti-migration devices. So you can see how that's placed over a guide wire. And that's the end product of a plastic stent. If you can start that video for me, Sam, we don't always just deal with issues in the tree trunk part of the bile duct here. We're in the left intrahepatic duct. If you use a slick-coated hydrophilic guide wire that has a 90- or 45-degree angle at its tip, you can flick it in and out of the catheter, spin it around, and by chance, find your way into exactly the branch duct that you need to get into. This was a patient whose right side was full of tumor. We wanted to get into the largest obstructed left system where we could place one decent-sized stent to drain that side of the liver. And if you can start this video, Sam, this shows you what it looks like on the endoscopic imaging side. You saw the X-ray imaging side, and this is what's going on on your scope view. So we're going to look at both of these images going on at the same time. So your eyes are darting left to right, left to right, and looking at both. And you can see a flexible type of plastic stent being inserted into that bile duct that's obstructed from a metastatic adrenal cancer. This style of stent has some side holes in it, as you can see, which will recruit drainage from side branch ducts. We can also stent the gallbladder. You can see the contrast in the gallbladder, but there's a white area in the middle, and that's where the gallbladder is. And that's a gigantic stone that was obstructing the gallbladder. The patient was too sick to have a cholecystectomy, so the surgeons asked us to place a stent endoscopically. And we can very easily get into the gallbladder, just like we can get into pretty much any specific branch bile duct that you need us to get into. So the stent is being placed, and this is what it looks like on the endoscopic side. Sometimes we'll place two stents into the gallbladder so that even if stone material obstructs the lumen of the stent, you can still wick between the two of them, and these things can stay open for years without exchange, unlike bile duct stents. There are also stents that are woven, or die cut, or laser cut out of metal or metal wire. There are many different kinds. Some are bare wire, which we call bare metal or uncovered stents. Some are embalmed with a silicone or Teflon type of material to allow them to be removable. The ones that are not covered embed themselves permanently into the tissue and are not removable, and therefore only for use in patients who have a limited lifespan from an unresectable malignancy, or that part's going to be resected at future surgery. So that is crammed onto a catheter thin enough to go through the scope. Once in position, the outer covering is removed, and the stent is deployed in the bile duct and fully expands over several hours to a day afterwards. The advantage of metal stents is that they can expand to diameters larger than the scope channel with pipes. The larger the diameter, the longer they stay patent. And so if in the right situation, if the stent can fully expand, the patient may be better off with a metal stent, not because it's metal, but solely because it's a larger diameter and will stay open longer. Pancreatic stents are typically smaller because the panc duct is smaller than the bile duct, but they also come in different shapes and sizes depending on what's called for in this situation. Much as with the luminal gastrointestinal tract, there are different kinds of dilators. Most commonly used are balloon dilators, just like in the luminal gut. These are all wire guided for the biliary and pancreatic systems, but we also do have Savory type tapered plastic dilators. They're just a thin Savory that goes over a wire that are a small enough size to go through the duodenoscope, typically to dilate one or the other duct system. We also have screw dilators that tap our way through and then allow us to follow that through with a balloon. They're inflated with a manometric inflation device. We not only have extraction baskets, balloons rather, but we also have baskets. These are analogous to the devices that are used in urology. We have cytology brushes that are typically wire guided. Pediatric biopsy forceps and dedicated pancreatic biliary biopsy forceps can be used under endoscopic and fluoroscopic guidance and needles too. Chalangioscopy and pancreatoscopy is the use of a miniature scope through the duodenoscope. So this is a scope and scope paradigm. This type of device has been around actually for about 30 years, so it's not new. Although the disposable platform that we use these days is only about half that old. This is an electronic device. It's single use, so it's rather expensive per use. But as you can see in my video there, there's an impacted stone that I'm going after to shatter it with a laser filament that I can place through the scope to break it up and then take the fragments out. That can also be used to look at strictures where you're concerned about tumors and other things that require a direct look at the surface of the bile duct. So we talked about the role of ERCP in bile duct stones. There are guidelines for what's high risk and what's lower risk, which will guide whether to go directly to an ERCP versus doing as we did in our polling question, going to a non-invasive, almost no risk procedure like an MR. As we talked about in the endoscopy preparation lecture, pre-procedural assessment is paramount. Before you start, you need to do this. You do your risk assessment for both the endoscopy and the sedation or anesthesia plan. If they have a do not intubate order, you're going to need to reverse that. And then antibiotics, we typically only give if there is a concern for incomplete drainage of the contrast that we put in. The reason is that our contrast has sugar in it and the mouth and GI tract that the scope goes through picks up bacteria. Sugar and bacteria in an undrainable bile duct is a bad combination and can result in a liver abscess. And so you want to give antimicrobial prophylaxis before the procedure and sometimes afterwards, orally after they go home for a few days in certain patients in whom complete drainage is not expected. We give either rectal endomethasin or diclofenac suppositories to reduce the risk post ERCP. Different practices have different outlooks on how to interpret the data, which is to say who to give that prophylaxis to and who not to give it to. Our pharmacy in-house formulates diclofenac for 10 bucks a dose. But if you buy endomethasin suppositories on the market, they're about 400 bucks a dose. And so this is not like taking a couple of Advil orally at home. You do have to think about cost effectiveness. Management of anticoagulation, what really makes ERCP in the high risk category is that sphincterotomy or if you're performing a balloon dilation. If you're not doing those things, ERCP alone is actually low risk. If you're just going in to brush somebody or even to perhaps remove a stone in a patient who already has a decent size sphincterotomy, if the indication for the anticoagulation or antiplatelet agent or platelet or both is a strong indication, you may actually be better off just keeping them on those medications for the procedure. Informed consent for ERCP, remember to talk about the risk of complications. The most common is pancreatitis. Thankfully, most ERCP related pancreatitis is mild, which is to say severe pain, a short admission to the hospital, pain control, NPO for a few days and IV hydration. That's mild pancreatitis. The severe necrotizing type is less common than say from stones. Perforation is relatively rare unless you're talking about a wire puncture of a duct. That can happen, but stenting at the time, as long as you recognize it, will get rid of that very quickly. Bleeding typically only if there's a sphincterotomy, that's typically easily treated with clips or cautery. And of course, there are anesthesia and sedation related risks that need to be discussed with the patient, as well as a misdiagnosis. And the fact that interventions diagnostically like brushings are typically only about 50% sensitive. So remember to discuss that a negative brushing by no means says that there isn't cancer present. And of course, always ask about whether the patient can accept blood or not. Some patients religiously are not allowed to receive blood transfusions. You need to know about that ahead of time. And we document that in our consent. Post-procedure, generally speaking, they can start clear liquids as soon as they're awake enough to not aspirate. There's no consensus on diet advancement. I love to eat, so I tell my patients, if you feel well and you wanna eat, you can eat whatever you want. One of my colleagues doesn't let them eat at all and only says clear liquids for 24 hours. You decide, your team decides. Monitor for clinical response to the procedure. If they're not having the expected response, something's not right. So arrange for proper followup, whatever that is to be. And I can't underscore enough, don't leave a stent in there that needed to come out. You need to put in the note what the interval is that that stent should be in place and when it needs to be removed and how to schedule that removal procedure. EUS is endoscopic ultrasound. Dr. Call covered this to some extent as well. This originally started out as a diagnostic technique and is now very therapeutic as well. Basically, this is an endoscope that has a small ultrasound machine built into the tip. And more often than not these days, this is a linear array echo endoscope, as you see to the right here, rather than a radial echo endoscope as was the original design where you see 360 degrees around all at once. The linear endoscope to get a 360 degree view, you would need to torque it. Around left and right. Now the big advantage of the linear endoscope is that any device that is passed through the accessory channel will go right through the plane of imaging. So you can actually literally watch what you're doing. EUS not only sees the surface of the mucosa as regular endoscopy does, but it sees the layers of the gut beneath the mucosa all the way out to the outer fibrous coating of that luminal gut. And so that is a very powerful imaging capability that really is unmatched by any other technology. So we said that EUS is used for diagnosis, but also for staging of various tumors, not just in the abdomen, but also in the chest and the pelvis, wherever that scope can get, it can help with cancer staging and also in obtaining a tissue diagnosis. Furthermore, there's all sorts of therapy that can be guided by the echo endoscope, such as drainage of a pseudocyst or pancreatic necrosis, draining a bile duct or a gallbladder that ERCP can't get to. Nerve blocks in various locations, injection of glue and coil into varices and other blood vessels. It's kind of like IR that way these days, as well as EUS guided ERCP, where ERCP is unsuccessful at obtaining cannulation. Sometimes an EUS approach can get that job done by throwing a line down across the papilla and to grade. Also anastomosis can be created such as a gastrojejunostomy or a hepatic gastrostomy, where there are blockages in the gut. EUS can be used to find a great window to create an intended fistula. And that fistulization is usually stented to overcome the obstruction. EUS is also very sensitive in picking up bile duct stones, as you can see there. Usually you will see that very clearly and as you do in this image, and you'll see shadowing of the sound waves beneath the stone. This is analogous to the image that Dr. Call shared with you already, where the instrument here, a biopsy needle that's advanced through the echo endoscope goes right through the image plane, and you can actually see that needle going in and out of the tumor. That's your biopsy. Get that pre-procedure assessment done. We already talked about that multiple times, so I won't belabor it. Management of anticoagulation, basically diagnostic EUS. If you're just looking, that's a low risk for bleeding procedure. It's not a big deal to keep the patient on antithrombotics. However, if you're going to do a needle aspiration or a biopsy or any of these therapeutic interventions that I mentioned earlier, those get you into the high risk for bleeding territory. You're usually going to want to hold the antithrombotics, although that's always dependent on what the indication for the antithrombotic medication is and how urgent the procedure is. If they're going to be able to stop those agents in two months and it's not an urgent procedure, why not just wait until they are able to stop it safely? This is a patient-to-patient thing that requires you preoperatively going through the chart and sometimes having an active conversation with the provider who has the patient on these agents for whatever disease they're treating with that. It's not about the INR. It's not a specific number we're looking for. It's more about how high risk for bleeding the procedure is and how strong the indication is for the antithrombotics. Just to remember, antithrombotics equals anticoagulants and antiplatelet agents. Those together combined are the category, the broader category of antithrombotics. Diagnostic staging EUS without FNA, as I just mentioned, is low risk. Informed consent for EUS is similar to what I described with ERCP these days. Practice pearls ERCP and EUS are essential procedures for management of GI and non-GI diseases. Appropriate patient selection is extremely important. Less invasive, lower risk tests ought to be chosen when possible. And I showed you what the guidelines tell us about that. Pre-procedure management of antithrombotics and operative risk is key to success and avoiding adverse events. And when complications do occur, early recognition and prompt expert management are essential and proper. Thank you so much.

ERCP

EUS

bile duct disorders

pancreatic disorders

endoscopic procedures

therapeutic interventions

patient care