Rita Knotts, MD, and Rena Yadlapati, MD, on the Chicago Classification 4.0

In this podcast, Dr Rita Knotts discusses Chicago Classification 4.0 for esophageal motility disorders on high-resolution manometry with Dr Rena Yadlapati, the primary author for the updated guideline.

Rena Yadlapati, MD, is the medical director of the Center for Esophageal Diseases at the University of California at San Diego. Rita Knotts, MD, is an assistant professor at the NYU Langone Center for Esophageal Health in New York City, and section editor for esophageal diseases for the Gastroenterology Learning Network.

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Reference:

Yadlapati R, Kahrilas PJ, Fox MR, et al. Esophageal motility disorders on high-resolution manometry: Chicago classification version 4.0. Neurogastroenterol Motil. 2021;33(1):e14058. doi: 10.1111/nmo.14058.

TRANSCRIPT:

Dr Rita Knotts:

Hello, everyone. Thank you so much for joining us here today. I'm Rita Knotts. I'm an assistant professor of medicine at NYU Langone Health and I work as an esophagologist at our Center for Esophageal Disease. We're here today with Dr Rena Yadlapati, who's the primary author for the latest version of the Chicago Classification version 4.0, to discuss the latest version and how we can approach the changes. We're doing this here today for the Gastroenterology Learning Network. Dr Yadlapati, thank you so much for joining us here today.

Dr Yadlapati:

Thank you, Dr Knotts. It's really an honor, and I'm really excited to talk about Chicago Classification and all things esophagus.

Dr Knotts:

Great. We're excited too. Let's get into it. So can you discuss the use and the evolution of the Chicago Classification? Why do you think we need this classification and the latest update to this classification?

Dr Yadlapati:

Absolutely. So it was just about 15 years ago when we didn't have a classification. And if you think back to that time, manometry was being done in many labs and all across the world, but the way it was being done was different— different protocols, the way that it was interpreted was distinct. You can imagine that we really weren't speaking the same language. One patient in one motility lab would get one diagnosis, and potentially, they could get a different diagnosis elsewhere. We often liken it to the story of the Tower of Babel, where people were speaking different languages and it was impeding collaboration, and really, progress.

But then in 2009, the first version came about. It really was a small collaboration with 3 experts in the esophageal field. Then it led to this international high resolution manometry working group. Now we're in the fourth iteration. And it's really amazing to see the Chicago Classification has become that quintessential classification scheme, and really meant to just unify how we approach manometry and how we diagnose it.

Dr Knotts:

So you mentioned a little bit about standardizing the protocol. Can you talk to us a little bit more about the change in this particular manometry protocol? What are the most significant changes here? And under the version 4.0, what's the recommended protocol, or is there a recommended protocol?

Dr Yadlapati:

Version 4.0 is really the first one to lay out a standardized protocol. So in the past, most people were using a similar type of protocol once the Chicago Classification had come out, but it hadn't been standardized, so there still were differences. What position was the patient being put in? How many swallows were we doing? So this was a key priority in 4.0, because really, in order for us to, again, speak the same language and then also to have research collaboration, we need to be performing the same type of protocol. So to do this, we had a working group that was specifically dedicated to it, and we really wanted it to be as evidence-based as possible. The protocol now, you could start off an either upright or a supine position, whatever your lab is used to, or you're comfortable with.

Most people I know—and I think that you guys do this as well—start in the supine position. So once the catheter is placed, we'll do 10 swallows. Those are 10 wet swallows. Now, after that—that is sort of the traditional, even what people were doing before 4.0—but now after those 10 swallows, it's recommended to have a multiple rapid swallow, so the stress test for the esophagus. And then we switch the patient to an upright position, or the opposite position. If you were upright, then you moved to supine. And then you do at least 5 swallows, wet swallows in the upright position or alternate position, and then a rapid drink challenge.

And we'll talk through maybe some of the diagnoses and how those apply for upright position and how that impacts it. But as far as whether labs can do this, yes, all of these are doable by any lab, really, any motility lab. What I just outlined is really the recommended protocol. Now, some patients, if they have achalasia and they're at a high risk of aspiration, you might decide to just do those 10 supine swallows and not move forward if there's a high aspiration risk, or if they're not tolerating. But otherwise, what I outlined is really the optimal recommended one.

Dr Knotts:

It seems like it's definitely more generalizable. And so would you recommend, at the minimum, keeping it to 10 swallows and also incorporating some provocative maneuvers?

Dr Yadlapati:

What I would recommend all labs do is 10 swallows in either the supine or upright position, a multiple rapid swallow, a rapid drink challenge, and then at least 5 swallows in the alternate position. I've been working with other labs where they haven't adopted this. And now when I see it, and now that we have 4.0, I'm like, "Oh, I wish I had those upright swallows because it really does make a big difference for some patients."

Dr Knotts:

Yeah. Especially when you're reading it in hindsight and you're questioning whether or not there's an outflow obstruction. I definitely think having a little bit of extra, having the upright swallows or provocative maneuvers, can be super helpful in making correct diagnosis. So can you discuss some of the new changes in version 4.0, and how this differs from 3.0 to make a diagnosis?

Dr Yadlapati:

Yeah. A lot stayed the same, especially most of the details with achalasia. But really, the key differences were that we wanted to distinguish certain patterns that we see on manometry, that when you see a pattern like achalasia, that is significant, that's actionable, but there are some patterns that we see on manometry that may just be patterns and don't require action, versus others that do need to be further evaluated and treated. And so we really wanted to distinguish between these types of disorders.

Probably the best example of this is EGJ outflow obstruction, right? Per version 3.0, EGJ outflow obstruction was one of the most common motility diagnoses seen on high resolution manometry. But when we look back, oftentimes it didn't really represent true primary dysfunction at the lower esophageal sphincter. It might have been from artifact or hiatal hernia or something that didn't really need to be treated.

For EGJ outflow obstruction now on manometry, it requires not only an elevated IRP in the supine position, but also in the upright position, and also intrabolus pressurization. And then even that, even if you have that, that meets criteria for a manometric diagnosis, but it doesn't necessarily mean that that is a clinical pathology that needs to be intervened on. So in order for it to be clinically relevant, the patient needs to have the right symptoms. And we even took it a step further where the patient needs to have another test that corroborates the outflow obstruction. We really wanted to minimize patients getting unnecessary invasive treatments if it wasn't needed.

There are other examples like distal esophageal spasm and hypercontractile esophagus. Those are kind of similar to EGJ outflow obstruction, where you might see it on manometry, but it doesn't always mean that we need to cut the muscle or relax the muscle. And so those also require the patient to have the clinically relevant symptoms before you think about acting or intervening. And then I think the one other change was ineffective esophageal motility, where the diagnosis became much more stringent. We were finding before that many patients had ineffective esophageal motility, but it might not have really related to their symptom burden. So now you have to have more than 70% of swallows that are ineffective to have a diagnosis of IEM.

Dr Knotts:

Do you think you can walk us quickly through the diagnostic algorithm of the Chicago Classification, just for our listeners here who are learning about this maybe for the first time?

Dr Yadlapati:

Yeah, of course. Really, the first pivotal question is, is that lower esophageal sphincter relaxing adequately when the patient swallows? So we look at the median IRP, and that's unchanged from prior versions. Now, if that median IRP is elevated, then you're thinking, okay, is this a diagnosis of achalasia or an EGJ outflow obstruction? And if you're looking at that algorithm, which is very busy, but if you're looking at it, then you're considering something on the left side. So type 1 achalasia is when all the swallows are failed. Type 2 is when all the swallows are failed and there's panesophageal pressurization. And then type 3 is when there's spasm and or all the swallows are failed. So those are your achalasias. Now, if you don't meet criteria for any of that, but that IRP was elevated, then you need to see, is it still elevated in the upright position, and is there that intrabolus pressurization?

And if there is, then you meet criteria for EGJ outflow obstruction. But if you go back to the top and you say, "Okay, nope, the IRP is normal," then now you're thinking of other disorders that are not achalasia-like. So is it absent contractility where all the swallows are failed? Is it distal esophageal spasm where at least 20% of the swallows are premature or spastic? Hypercontractile esophagus where 20% or more of the swallows are hyper contractile? Or as we talked about, is it ineffective esophageal motility? If your answer to all of that is no, you might have someone that has normal motility, or it might still be that that there's some subtle process going on. And so we do have some recommendations in the Chicago Classification. You could think about solid test swallows, pharmacologic provocation, so forth, if you really have a high suspicion of some process that wasn't detected according to that algorithm that we just talked about.

Dr Knotts:

Thank you so much. That was such a great summary. I think I have one last question for you. How do you think these changes alter management of how we treat these disorders right now? And how should we incorporate them into clinical practice?

Dr Yadlapati:

Yeah. Hindsight is always 20/20, and it's interesting. First, you're always a hard critic of, did we take the changes too far? Did we not do enough? But time tells, right? So recently, I've come across many studies that have looked at trying to validate whether the changes in 4.0 were clinically impactful. And I'm really happy to say that there have been many studies that are coming out that are positive. So for instance, intrabolus pressurization requiring obstructive symptoms correlates with meaningful EGJ outflow obstruction and with what we see on barium esophagram. So really, really think about that EGJ outflow obstruction. If you just see the IRP elevated in your 10 supine swallows, don't make a diagnosis of EGJ outflow obstruction. Look at the rest of the manometry. Look at other studies. I think that's probably one of the most important changes.

And then we're also seeing, now we have functional lumen imaging probe, right? The FLIP technology. We're seeing that patients that have distal esophageal spasm or hypercontractile esophagus on manometry, many of them on FLIP, they don't necessarily have achalasia, but they have this spastic reactive process. And maybe this is from GERD. Maybe this is a reactive process from something else, but it's not the primary LES dysfunction. So once again, don't necessarily send your patient for a myotomy, just because you see this pattern on manometry, but really think about it. Look at your other studies, look at their symptoms.

Dr Knotts:

Thank you so much. This is very helpful. And thank you for that amazing summary of the Chicago Classification. We're so happy to have had you here today. Thank you, Dr Yadlapati, and we look forward to hearing more from you and to following your work.

Dr Yadlapati:

It's truly my pleasure. Thank you so much, Dr Knotts.