SADI_OAGB_Final

Hello and welcome to the BTK audience. This is Matt Martin here with the Behind the Knife Bariatric Surgery team. We've got a great episode today. We're going to be talking about a couple of recent articles. On some newer or lesser well known bariatric procedures, which are single anastomosis procedures, the one anastomosis gastric bypass, and the single anastomosis duodenal ileostomy.

I'm Matt Martin. I'm a bariatric MIS surgeon at University of Southern California. Hello, everyone. My name is Paul Vyshnovsky, and I am a fourth year resident at the University of Southern California. And I'm Adrian Dan. I'm an associate professor of surgery at Northeast Ohio University and also a bariatric MIS and foregut surgeon at Summa Health in Akron, Ohio.

And we've got a new member of the team today. Hi, everyone. I'm Crystal Johnson Mann. I am an assistant

professor at the University of Florida, where I am one of the bariatric and foregut surgeons. So I'm happy to join the team. Welcome. Great to have you. All right. So before we jump into these papers, I know that not all of our listeners may be familiar with the procedures we're going to cover.

So to start off, Dr. Martin, can you give us a brief outline about of an OAGB? Sure. An OAGB stands for one anastomosis gastric bypass. It was most commonly called a mini bypass. But O A G B is now kind of the official abbreviation we've all decided on not done very often in the U. S. But it is done very commonly in Mexico and some parts of Europe.

So you likely will run into this procedure at some point. And basically it's a gastric bypass with a single anastomosis loop gastrojejunostomy rather than a roux y reconstruction. So it, it consists of making a gastric pouch

that's somewhat longer than a standard pouch you would make for usual gastric bypass.

Usually formed over a 34 to 36 French bougie. A loop of dejunum is then measured, typically about 150 to 250 centimeters from the ligament of trites, brought up to the stomach and then an anastomosis is created by a variety of anastomotic techniques that have been described. Interestingly, the original description of the gastric bypass was a loop in 1969 by Dr.

Mason, isn't that right? Yes, and this is considered a version of that original loop gastric bypass. And in terms of the pouch I usually conceptualize it as it's about half of a sleeve. So it's a longer pouch than you would get with a normal gastric bypass. If you think about the size and shape of a sleeve, if you kind of divided that about midway, that's about the size of the usual gastric pouch for these.

That's perfect. So the procedure has been described as a simpler operation like Dr. Martin mentioned that

eliminates the jejuno jejunostomy and the typical Roux en Y gastric bypass and thereby theorized to reduce the risk of potential leak sites and internal hernia. Dr. Dan, would you be able to go over a SADI?

So this operation is also referred to as the loop duodenal switch. The first part is to complete a sleeve gastrectomy, although the conduit is typically somewhat larger than for a standalone sleeve. It can be constructed over a 50, a 60 French bougie, or even over a 40 very loose sleeve. The dissections then carried out distally past the pori for about two to three centimeters of the duodenum, which is dissected and divided.

This requires a retro duodenal de dissect, and the gastroduodenal artery is the landmark of the dissection limit. I then count 300 centimeters of ilium. That can be increased or decreased depending on the patient, but I do that by five centimeters because it's so important to make sure that you have a good

count of this common channel.

At 300 centimeters, I perform a duodenal ileostomy, either with a linear staple or laparoscopically, or in a hand sewn fashion, robotically. So the CDS can be done as either a primary procedure or in stages with first a sleeve gastrectomy, followed by a duodenal ileo bypass later. Again, this procedure has increased interest as it eliminates anastomosis from the classic duodenal swish.

making the argument that this may be actually a little safer. Awesome. Now that we have some of the background information covered, let's dive into our first paper. We're going to look at the outcomes of the SADI and OAGB compared to the bypass from an MBSA QIP study. This is a retrospective observational study that uses the MBSA QIP database.

The author, authors reviewed the 30 day complications of SADI and OAGB compared to bypass between the years of 2018 and 2021. So one of the things to kind of keep in

mind with this data is that it's somewhat limited because it's only mostly providing 30 day outcomes. So it's not going to be the best study to evaluate some of our more prominent bariatric outcomes such as weight loss and effects on metabolic outcomes.

However, it does provide some solid information as to the technical complications of these procedures. Yeah, and you know, our patients like to be presented with the 30 day outcomes in terms of their decision making, but really, they want to know what's going to happen for the rest of their lives. Most of them should live more than 30 days and that's what they want to know.

But in this particular study, the authors reviewed nearly 180, 000 patients. This looked again at the MBSA QAP database over about three years. And as we all know, most procedures are sleeves. So what was left behind is the patients who had gastric bypass, SAD and OAGB. Of those, roughly 98 percent underwent gastric bypass due to the current popularity of the procedure.

The SADI and

OAGB groups were then propensity matched to the bypass group based on age, sex, BMI, operation length, and ASA classification, and that's how they were compared. Yeah, and they looked at outcomes between the SADI compared to the RU I gastric bypass. And then they looked at outcomes between the one anastomosis bypass versus the standard Roux Wyatt gastric bypass.

And they did pretty standard univariate statistical comparisons for those outcome measures we talked about. And then they also did logistic regression modeling to identify any significant independent factors that were associated with the outcomes and those associated odds ratios. Yeah, but in terms of the outcomes, at least for mortality between the two groups, there were no differences in the or the Sadie cohorts compared to the bypass groups.

However, in the Sadie versus bypass analysis, Sadie patients were found to have higher rates of staple line leaks,

sepsis, organs based infections, as well as pneumonia's. Yeah, and I think it's important to consider too what outcomes. So, so looking at mortality, that's a horrible outcome for modern bariatric surgery because it is such an uncommon outcome, right?

You would need. Hundreds of thousands of patients with modern methods to try to show any difference in mortality. So that's not a great outcome. But the other outcomes, they did show some worse outcomes with the Sadie, which is interesting. But despite the higher rates of these post operative complications, they really didn't see a difference in readmissions re, operations or other interventions.

Between the SADE and the gastric bypass and interestingly, the SADE patients had a significantly lower rate of ER visits, which seems contradictory to the complication data. Which is interesting, actually, as you say that, because one of the important outcomes that's not listed in this study

is actually hospital stay.

And so potentially, there is the chance that the SADE patients have longer hospitalizations, which in turn may explain some of which, why they had decreased ER visits. I'm not surprised to see SADI having more complications given the novelty of this operation in North America. The ASMBS endorsed the procedure in 2019 and as it gains popularity, as with any procedure we've seen in the past, I'd expect to see a dramatic drop in the complications.

As surgeons become more familiar and more comfortable with the dissection and the procedure, I think that's just a matter of time. I think the experience with gastric bypass somewhat goes along with that, or especially when we transition from open to the initial laparoscopic gastric bypass. Leak rates were 6%, even up to 10 to 15 percent in some series, and those have now come way down.

So most centers have a leak rate

that's around 1 percent or less. So there is something to say about the learning curve. But I would say it's often not as simple as that because what we see with new procedures often are you have innovators, very small group that start doing these. They tend to be.

Very experienced surgeons they standardize it, they get very good outcomes. Then when it starts to become more widely adopted and we say, Oh, complications are going to decrease because now we're doing it more. But that's usually when you see an increase in complication of these people who don't have the experience of those innovators start trying to do this.

And they realize that, Oh this is a little harder than I imagined. So oftentimes you'll see an Increasing complications with wider adoption and then later a drop in those as they, they get a learning curve, but also serve on the adoption aspect. This is the argument of going between open surgery to laparoscopic surgery to robotic surgery.

There is that adoption that does have to take place.

Absolutely. I think you guys hit the nail on the head and Matt, that's why you have so much gray hair. I'd like to say. Less and less every day. Well, I've been an early adopter of CDS. The retroduodenal dissection can scare some people off at first, and it can be challenging, especially in patients, the previous open call cystectomy or other previous foregut operations.

However, with time and patience, it actually becomes fun and becomes enjoyable to do the dissection. I'm a proponent of a complete dissection, which includes taking the right gastric artery and straightening the sleeve conduit. But some experienced surgeons will perform a minimal dissection and create a tunnel behind the duodenum to pass the stapler, reducing the amount of work and preserving some blood supply to the duodenum.

But it's it's a lot of fun once you get the hang of it. The learning curve is not that steep for experienced bariatric surgeons. Yeah, yeah, I agree. And I did a lot of duodenal switches. So

once you get comfortable with that dissection, I agree. It is, it's a fun dissection. It's something a little different than what you're used to doing.

But even then the anastomosis between the duodenum and the jejunum, I think that's just generally something that most bariatric surgeons are less conscious of. commonly performing or less comfortable with. And as bariatric surgeons, we're very accustomed to doing gastrogygenostomies. So, so a very low leak rate for those.

And it's not surprising there might be a slightly higher leak rate as we start to do these duodenal ileostomies. There's also the fact that the stomach is a pretty hardy organ. It takes a lot to hurt. It takes a lot to injure the blood supply. The same is not true of the duodenum. So, so Poor handling of that tissue can really lead to inadvertent injuries that you wouldn't see when you're just handling the stomach.

No, absolutely. The duodenum is not friendly territory by any means. And so absolutely bringing the together, the anastomosis can be consequential if you do have any

tissue handling issues. The paper mentioned a sub analysis comparing SADI cases done in 2020 versus 2021. They noted that the higher odds of infection, leaks, and unplanned intubations was not consistent in 2021 with what was seen in 2020.

This supports that there is a learning curve, but the data does not track surgeons and the institutions. You know, we did our first fusadiases laparoscopically and then quickly adopted a robotic approach with a hand sewn duodenal ileostomy. It's really a lot of fun and becomes second nature after about 10 to 20 cases.

With more adoption by more surgeons, we probably will see some more complications before the rates decrease. Yeah. I also think it's important. To understand when papers say, oh, there's an increased rate of leaks and our odds ratio is three. And that sounds horrible, right? Three times the rate, but

you also need to know what the absolute rates you're talking about.

So, you know, you'll have a 0. 1 percent to a 0. 3 percent and it's, oh, it's an odds ratio of three, but. You're talking about extremely uncommon events. And that's one potential criticism of this analysis too, is they report odds ratios and they don't actually give you the raw leak rates, which again, I'm sure they're definitely less than 5 percent and guessing they're probably two to 3 percent or less.

So, so you have to also just remember to look at the absolute rates and not just count on odds ratios, because those are often used to inflate. something that may not be clinically significant. But let's talk about the other analysis. So they also then compared one anastomosis gastric bypass to standard Roux en Y gastric bypass.

Interestingly for this, there was no difference in anastomotic leaks as was shown with the SADI. But the one anastomosis operation did have reduced odds of a couple complications like

surgical site infections, transfusion requirements, or GI bleeds. ICU admission and post op bowel obstructions.

Additionally, they found lower healthcare utilization which lowered re operations, re admissions and interventions in the OAGB group. You know, you know, Dr. Martin, it's interesting to me because like, like the SADI, the OAGB is relatively, I guess, newer operation as well, but compared to that, this seems to have better short term outcomes compared to the rheumatoid gastric bypasses.

Any thoughts on, you know, Why, though, those outcomes might be improved? Well, the OEGV involves a gastrogygenostomy, a procedure that's familiar to bariatric surgeons. Plus, it has one less anastomosis, one less place where you can have bleeding, leaking, and it reduces some of the postoperative complication risks.

Plus, sort of thinking about the complication list that was part of this study, they seem to be related to the elimination of an anastomosis.

And so we know bleeding often occurs, as we've just sort of mentioned, at a staple line, either intraluminally or extraluminally. So decreased transfusions and GI bleeds make sense.

Yeah, and it's hard to say again exactly why the OEGB had lower complications based on this data, which is from a big national registry, where a very, very few centers are doing the OEGBs. And then they're taking the RU I gastric bypass group from essentially. Every center across the country while these data are optimistic, and I think they do support that the seems to be a reasonable operation with comparable or even better, very short term complications, the tail of bariatric surgery outcomes are told in decades.

So, we really need to know outcomes like weight loss, nutritional complications, because we know loop G. J's have complications. Right? And the board

answer to all of those is what? Convert it to RUI. So, so we really need that longer term data, I think, before we start widely adopting it. Awesome, thank you guys.

So, to summarize these results just very briefly, the SADE was associated with higher odds of postoperative complications, which appear to be somewhat related to an anastomotic leak. While on the other hand, the OAGB had reduced short term postoperative complications, but as everyone had mentioned, these are all short term data and longer data are required to make better conclusions onto these studies.

Nevertheless, I think that this feeds well into our next study. The Y Omega trial. Full name of this is the efficacy and safety of the OAGB versus Roux en Y gastric bypass for obesity. This is a multi center, randomized, open label, non inferiority trial that was done in France, which evaluated the outcomes of the OAGB versus the bypass after two years.

Now

there is a lot to unpack with this one. Dr. Johnson, man, if you would like to get started. Absolutely. So the patients that were enrolled in this trial were either were BMI of 40 or greater or 35 or greater with comorbidities. The authors excluded patients with esophagitis, severe GERD that was resistant to proton pump inhibitors, and previous bariatric surgery.

Yeah, and of course, it's always critical when you're reading studies like this to look at, well, what was the exact technique they used? Because it's technically not a, randomized trial of OAGV versus gastric bypass. It's a randomized trial of this technique of OAGV versus this technique of bypass. So, their bypasses had a standardized pouch size of about 30 mls, although they never specify how they calibrated that.

And a 150 centimeter roux limb and 50 centimeter biliopancreatic limb, which I think is pretty good. Pretty standard. Now the O. A. G.

B. S. Were created with long gastric tube over a thirty seven French bougie starting at the end Cesara. And then in terms of their limb lengths, which is critical, they use the 200 centimeter biliopancreatic limb.

So they ran it 200 centimeters from the ligament of trites, brought it up to the stomach and did a linear stapled gastro jejunostomy. All of the patients had standardized post op care regimen, including vitamin supplementations. I think it's important to put this paper in perspective a little bit. Some of the prominent surgeons that do OAGB in the world are from France, and the French have a slightly different health care system.

Well, for the most part, you can only get your bariatric procedure at a center, a designated center of excellence. So after the study was done and commissioned by the French government to determine the Capabilities of the procedure versus the incumbent Roux en Y gastric bypass. To this point, as that I know of, you can no

longer get an OAGB in France.

And the primary endpoint was percent excess BMI loss at two years with a variety of secondary endpoints including weight loss, BMI, operative time, length of stay, GERD, steatorrhea, and metabolic profile. Of note, an endoscopy was performed on patients at two years postoperatively. Yeah, and then the author said a non inferiority difference of 7 percent between the two procedures.

That's assuming a mean percent excess BMI loss of about 60 percent at two years. There were a total of 234 patients with 117 patients per group. All data was analyzed with an intention to treat and missing data was was amputated for missing data in the per protocol population. There were approximately 21 percent of the and 24 percent of their run wide gastric bypass that were lost to follow up, which is which are interesting numbers to that's a pretty high loss to follow up rate, which

factor that into your interpretation.

So, looking at their outcomes. Their weight loss outcomes were actually pretty good and on the higher end I think of what's usually reported for gastric bypass. So the mean percent excess BMI loss at two years was essentially 86 percent in the bypass group and 88 percent in the OAGB group.

Essentially no difference. A mean percent difference of about 3%, which was not statistically significant. So this did demonstrate non inferiority between the two procedures or. OAGB is not inferior to the standard gastric bypass in terms of weight loss at two years. The OAGB group had a greater number of serious adverse events, 42 compared to 24 in the bypass group.

While there's a sizable difference between these figures, when evaluating the proportion of patients with at least one serious adverse event, there was no difference between the groups. And furthermore,

there is no clear data on the reoperation of the two groups, but they mentioned four OAGB patients required conversion to a Roux en Y gastric bypass for various reasons, and five Roux en Y gastric bypass patients with abdominal pan to wind reoperation.

Yeah, so, so due to the configuration of the anastomosis, There seems to be more of a trade off between the two procedures with OAGV patients reporting more reflux symptoms, which then required conversion to a gastric bypass, but the gastric bypass patients being at an increased risk of the typical internal hernia.

Or chronic abdominal pain that prompts another surgery to look for an internal hernia. Yeah. One of the risks is the from what I understand increased reflux from the OEGB or risk of it. Did the authors report on gastritis or esophagitis in these cohorts or in this specific cohort? Yeah, the, they actually perform endoscopy on their patients at two years.

16% of those

patients in the OAGB group had bile in the stomach, but there was no difference in rates of gastritis or esophagitis between the group. Of notes. One patient in the OAGB arm had intestinal metaplasia in the stomach and esophagus, but no dysplasia. Yeah. And then they looked at a bunch of secondary outcomes, including some important metabolic outcomes.

And actually the OAGB had a greater reduction in hemoglobin A1C with about a 2.3% reduction compared to 1.3 with the rig gastric bypass. And in a subgroup analysis of patients with diabetes. Actually, 60 percent of those patients had complete remission with the OAGB compared to 38 percent in the gastric bypass arm.

However, this was not statistically significant, which could be due to either there's truly no difference or there is a difference and the study's underpowered to detect it. In addition to that, they also found,

as we would expect, that the operative time was significantly shorter for OAGB, about 85 minutes, compared to 111 minutes for the Roux en Y gastric bypass.

And of course, this makes sense. It's an operation where you have one fewer anastomosis and less to do. You know, what's the other shoe drops. So the OGB patients did have higher rates of nutritional complications, actually a rate of 21 percent compared to zero in the gastric bypass group. One patient required conversion from an OGB to a gastric bypass for Wernicke's encephalopathy.

Also, six of those patients developed diarrhea or anal fissures, which suggests a greater melatonin effect of the one niacinosis gastric bypass. But they mentioned at least from the metabolic profile cholesterol, hyperlipidemia and triglycerides as well as albumin and prealbumin, there were no differences between the two groups.

Yeah. And it's not surprising to see an increased nutritional complication rate with with the OAGB. And Whichever complication you look at, you have to remember there's really good pearls, surgical pearls that you have to abide by in order to decrease the amount of gastritis, the amount of bile reflux, and of course, the amount of nutritional complications that can arise.

With a limb of 200 centimeters, you're going to see more and for that reason, some authors have recommended decreasing that to a standard of about 150 centimeters for the. aferin limb or the biliopancreatic limb as it's also known to mitigate these issues. But it's important to consider the total elementary limb, which in this operation is also going to be your aferin limb or your common channel.

And many surgeons who do this operation will not take the time to count that. You've got to make sure you count that because with this type of an operation where you have a relatively small pouch without a

pylorus and a lengthy biliopancreatic limb, You need probably at least 400 centimeters of common channel and you should not do this operation if your common channel is going to be less than that because you will run into these problems.

Matt, what do you think about that? Oh, yeah. Well, I mean, just per the study protocol, we have no idea. what the common channel and total out of memory lengths are. So they're just measuring a BP length and then assuming they have enough common channel. But we know the length of small bowel can vary significantly between patients.

So I agree 100%. Lastly, they did look at quality of life, which, of course, another important measure at the two year time point. And they use several validated survey tools, including the Barrows and the I. W. Q. O. L. Surveys. There was no significant difference in patients who reported either a good or better outcome in which was reporting 86 percent of that group compared to 94 percent of the bypass

group.

So both groups were reasonably happy with the results of their operation. But in summary, OAGB was associated with decreased operative time with non inferior weight loss, albeit possible increased metabolic deficiencies, which may be limb dependent, as we sort of discussed about variance in limb length and equal improvements to quality of life.

The only other thing that I would add is just that we can't be complacent with the status quo, and this is why we are always trying to improve care for our patients, because as we know, obesity in and of itself is multifactorial, and there's not one operation that's best suited for one patient for all patients, and so we're still in this sort of trying to manipulate ways that we can continue to improve upon these outcomes, and this requires Dr.

Sometimes changing procedures and looking at different techniques and, but the bottom line is with that information, as we've talked about kind of throughout this podcast already is the length of follow up is especially important because there's a certain things we're not going to know one year, two years, five years.

And this stuff is going to take decades to

arise. And so we're just really not going to know until we have more follow up, but certainly these procedures are here to stay. Yeah. And maybe in the last few minutes we can just each comment on where these procedures fall into your current practice or where you see they think they fit best.

For me I'm not doing OEGB and I really haven't been tempted to and I'm I don't find the second anastomosis to be that much of a detriment or difficult. Sadie though, I think is a great option. I see its biggest role, at least in my practice, is the prior sleeve who has not lost an ideal weight or who has weight recidivism.

So florida is really interesting. So we have a unique patient population where we are at UF. And so, we are certainly not doing one anastomosis gastric bypasses. And I even come up to sort of the forefront of our thought processes. I agree with you for Sadie is a great operation for patients with weight

regain after a sleeve or inadequate weight loss.

The issues that we run into in our part of Florida is our payer mix. And so Sadie is not something that is actually covered by most of the insurances. And, but you, and you have no temptation to try to start doing OGBs. I have zero temptation. This data is not making me more tempted. Nothing against any one procedure.

All of these procedures have saved more lives than any trouble they've been. For that reason, I adopted Sadie about four years ago. But my algorithm has been to to do sleeves on the majority of patients that don't have severe obesity or severe diabetes. And to reserve Sadie for those patients where the disease is so bad.

So severe that they will need something much more powerful than the sleeve gastrectomy. The sleeve gastrectomy is a nice place to, for an entry. And when people say, well, then you've got to do two operations. And the insurance company doesn't like that. I

always remind them that I don't work for the insurance company.

I work for my patients. What about OAGB? Well, initially it went from a loop gastric bypass 1969 to the Roux and then the mini gastric bypass, and it turns out, as you mentioned, that the metabolic impact may be slightly better than the gastric bypass. So shorter operation, fewer possibilities of internal hernias.

A better metabolic outcome. I think it's a win win and that's why I think eventually it will be adopted. But at this point I don't, I think the worst thing for the OAGB is that it came a couple years after the Sadie in North America because a lot of people see the benefits of the Sadie and want to leave that pylorus in place to avoid bioreflux and dumping and you know the other things that could come with a smaller pouch All right.

I agree. But the most important thing we want to know though,

so Paul you're going to be doing a fellowship doing these and you're a patient. Do you want to have an OAGB or a SADI, or do you want to stick with our traditional operations? I suppose this will be a good way to sum up these these papers.

So, I am optimistic about some of the outcomes of these these operations. However, I think that there is still some data, at least long term, that I would like to have before committing myself to either an OAGB or a SADI. I'll stick with the traditional ones for now.

All right, well, that was a great discussion. This is an important topic, especially with Sadie you're going to be seeing a lot more of these. I actually, I agree with both of you. I think it is a great option for the right patient. I want to thank everyone for joining us reviewing these two important papers.

And we will close out. Let's do a dominate the day all together. Okay?

Dominate the day!