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Interview by Jodie Elrod

Watch as Bradley Knight, MD, and Christopher Ellis, MD, discuss the 2025 SCAI/HRS Clinical Practice Guidelines on Transcatheter Left Atrial Appendage Closure at HRS 2025.

Bradley Knight, MD: Hi, I am Dr Brad Knight, Director of EP at Northwestern in Chicago. I'm also the editor of EP Lab Digest. We're here at Heart Rhythm 2025 in San Diego. The last time we were here was in 1999. I'm joined by my colleague and friend, Dr Christopher Ellis from Vanderbilt University. Chris has been a leader from the very beginning with left atrial appendage occlusion (LAAO) techniques and technology. He is really a high-volume implanter and is very experienced and has been involved with the new Heart Rhythm Society (HRS)/Society for Cardiovascular Angiography and Interventions (SCAI) joint document on guidelines for LAA closure and just presented some of the highlights of this about an hour ago at the meeting. So, welcome. Thanks for doing this, Chris. Can you start by telling me a little about how you got involved in this and what the impetus was to form this HRS/SCAI joint venture? 

Christopher Ellis, MD: Sure. Thank you for the invitation. SCAI initiated this and reached out to HRS leadership for the names of a few folks to be the leader or the co-chair from the HRS side. So, I was nominated for that and accepted it. That role is half electrophysiology (EP) and half interventional cardiology (IC). Dr Andy Goldsweig is the other co-chair from the interventional side, and he is in Massachusetts. There is a balanced panel of clinicians, many of whom are experienced LAA implanters from HRS side, and then there is also the same number of SCAI participants on the panel. There was also a technical review panel, who honestly did most of the heavy lifting in terms of doing the meta-analysis of the trials and data to get us something we could review and make a statement about that would make sense. There was also an evidence foundation partnership with both groups. So, it was a series of meetings. It took us about 9 months or so to get to our current draft, which is under review. 

Bradley Knight, MD: So, the status of this document is that it has not been published yet, is that right? 

Christopher Ellis, MD: Not published yet. It should be fairly soon, as soon as the HRS group internally approves the verbiage. What's interesting to me is just how detailed and nuanced every word in a clinical practice guideline needs to be. It's a careful choice—what you say can be interpreted in a lot of ways, but it must be very clear and then backed up by evidence, so we feel strong about the wording. 

Bradley Knight, MD: All these guidelines are there to help take care of patients in the best way possible, but once they're in print, they're often treated as gospel not just by other people, but by payers, attorneys, and litigation. I've seen the content of some of this, and I think there were 8 takeaway messages that you came up with. Could you tell us what those are? 

Christopher Ellis, MD: Yes, so what we did was take a series of questions based more on IC; their academic process includes something called PICO, which stands for population, intervention, comparator, and patient-important outcomes (PICO). So, for any question, you ask that group, you look at the details, and then also benchmark it to what the patient perspective, payer's perspective, system’s perspective, and clinician/researcher perspectives would be, so that you have all the different components. The way it is worded is very much like a patient would reasonably choose this option if they were X, Y, or Z. We listed all these questions, the top ones by priority were given a score, and those were the ones that we put in the guidelines. There were 8 of them, and the top 2 were specifically about the indication for LAA closure. So, I think that was where a lot of the heavy discussions took place. How do you word for a patient with atrial fibrillation (AFib) and a contraindication for anticoagulation? If they cannot take anticoagulation, are they better with an appendage closure device or no therapy? 

It seems intuitive and that we should be able to answer that question, but when you actually dig through all the trials and data, there's almost no study for that population. There was one study in a dialysis population looking at no anticoagulation versus anticoagulation, and so, the level of evidence is very low and our recommendation is what we call conditional. It means most patients would probably say they'd rather get an appendage closed than do nothing in that scenario. The next question is really a huge population. It's patients with AFib, no contraindication. Should they be on a blood thinner or should they get LAA closure? For that one, there is a moderate level of certainty, because we have several randomized trials, and for patients who had a contraindication, the panel said this is a reasonable thing for patients to choose, and we would suggest they could either get an appendage closure or take anticoagulation with the risk that comes with that blood thinner. But for the patients who are at low risk for bleeding, we made no recommendation, because we are still waiting for some really convincing data. The OPTION trial gave us a glimpse. CHAMPION and CATALYST were the big ones that will come in here in the next few years and maybe change that statement a little. 

Bradley Knight, MD: Still, even if there's benefit in one arm versus the other arm, it's very hard to come up with recommendations that say this person must have an appendage closure or vice versa, because there has to be some judgment. Not all patients are candidates and not all patients are capable of undergoing the procedure. What were the contentious issues? 

Christopher Ellis, MD: That was one of them. So, those were the first 2 questions. The next series was about imaging. What do we recommend? Should you get preprocedural imaging or not? It's a big topic. People have to travel. They get anesthesia for a transesophageal echocardiogram (TEE). It is an extra cost, but there is data that shows you probably do better if you have preprocedural imaging in terms of one implant in and no leak. So, we would generally recommend you do a TEE or computed tomography (CT) scan, but it's a conditional recommendation with a low level of evidence. 

Bradley Knight, MD: Yes. Well, it's an interesting question. We always get preprocedural imaging. We did TEE, now we do CT. There are some advantages, pros and cons, false-positives, and clots on the CTs that need follow-up, but the reality is it is a practical issue. The patient is coming in for procedure, so you need to be doing all that. They’re on the table, so you're going to do another TEE or ICE or some other imaging. It's not as if no imaging is used during the procedure. 

Christopher Ellis, MD: Correct. Yes, that's a different concept. I've heard of some folks doing imaging like LAA closure without fluoroscopy, which is an interesting concept. If you have good enough mapping and ICE and 4D ICE and all this new technology, that stuff is outside the scope of the guideline. 

Bradley Knight, MD: Rodney Horton presented a live case the other day here at the meeting. It was a concomitant procedure and he did no preprocedural imaging. 

Christopher Ellis, MD: So, I think that one was up for debate, and follow-up imaging is the other one. There is no proof in the literature that implanting the device and then doing some imaging affects outcomes. However, there is another bullet point in our guideline about device-related thrombus (DRT). That is a key factor—in a lot of DRTs, half of them show up late, beyond 45 days. So, 1-year imaging is still likely a good recommendation for people to detect DRT late. 

Bradley Knight, MD: Yes, we've talked about that as a group. We're probably doing a little more based on their risk, but it has not been routine for us. Do you routinely do that? 

Christopher Ellis, MD: We've been routinely doing it. 

Bradley Knight, MD: TEE or CT? 

Christopher Ellis, MD: Whichever. 

Bradley Knight, MD: You're mainly looking for DRT at that point? 

Christopher Ellis, MD: At that point, correct. But you already know about leak. 

Bradley Knight, MD: Yes. But at 45 days, the patient is still anticoagulated, almost all those patients are. So, the real question is, for someone who is permanently in AFib, with a big atrium, do they need to get imaging a year later? 

Christopher Ellis, MD: Yes. So, that was another one. The other ones where we had no recommendation, meaning we had zero data and there was a knowledge gap, is DRT. So, for a patient with a DRT, should they be put on anticoagulation indefinitely, or should you do nothing? There is no recommendation. We probably see a lot of DRTs that spontaneously resorb, and/or some of them are more laminar and fibrotic and are not sending off embolic events, and not all patients with a DRT have a clinical event. In a lot of patients, it shows up as an incidental finding with DRT being picked up on CT. So, we had no recommendation. There have not been any studies to really evaluate that. 

Bradley Knight, MD: It's a challenge, because many of those patients have contraindications to anticoagulation. 

Christopher Ellis, MD: Correct. 

Bradley Knight, MD: On the other hand, if you see a clot, the odds are high that you're going to treat them. Actually, we recently had one of our first cases with an embolic event, a huge DRT. There is also the option of surgery. 

Christopher Ellis, MD: Yes. To that point, DRT could be a non-issue if you just took the LAA off, whether that is done surgically, via clipping, thoracoscopically, etc. Unfortunately, I think that is not commonly available to most EPs. So, it becomes more about endocardial devices being the first option, and dealing with the DRT later is what we get stuck with in about 2% of cases. The other is peri-device leak of any amount. Anticoagulate or do nothing? I don't know the answer. It is not really something we can recommend one way or another yet. It's an important thing, because people are closing leaks and putting high-risk bleeders back on blood thinners, or maybe not doing anything if they have no transient ischemic attacks (TIAs) or embolic events. But we don't really know yet how to recommend treating peri-device leaks, at least to the level for it to be in a guideline. 

Bradley Knight, MD: Yes, so the guidelines often are very strict about requiring evidence, even though it is true, you must make a clinical decision in real-life practice. So, of the recommendations, I think there were 2 areas you felt were open for more research, even though the ones that have no recommendation also fall in that category. 

Christopher Ellis, MD: There is another one that had no recommendation, but there is more research taking place. That is the SIMPLAAFY study. So, the question would be single antiplatelet therapy (SAPT) after the device implant versus dual antiplatelet therapy (DAPT) or anticoagulation (OAC). The committee said that we don't have any data to do SAPT versus DAFT or versus OAC, but the SIMPLAAFY study is looking at Watchman (Boston Scientific) patients and having a prescriptive regimen of aspirin only, DAPT, or OAC. 

Bradley Knight, MD: Yes, there is some data on patients who had their DAPT suspended earlier, anticoagulation suspended early, surprisingly showing it was pretty safe, but we'll learn more. Were there specific things you thought needed or that had gaps in knowledge? 

Christopher Ellis, MD: One thing I thought that was interesting was on ICE versus TEE. The volume of these procedures is growing, especially with concomitant, and there is going to be a push for a lot more ICE utilization. Just based on the numbers, if you treated 1000 patients with ICE versus TEE for the implant, there were 5 more deaths per 1000 patients. Personally, I felt like we should recommend TEE over ICE, but the number that they had sort of set as our initial benchmark was 10. So, if we had 10 in 1000 deaths or more, it would have been enough to warrant a signal that you should probably not do ICE. So, I'm still a little nervous about that.

Bradley Knight, MD: I remember you told me before that you kind of went in the ICE direction. For almost all our cases, we still do both. It's kind of nice to have both. We've been not quite comfortable pulling away from having the TEE, and think I remember you kind of exclusively used ICE for a while and then kind of moved back.

Christopher Ellis, MD: Yes, largely because I was seeing more leaks no matter how hard we tried. But that seems to be just a side effect, that 20% of these devices will have some leak. 

Bradley Knight, MD: Finally, this is a joint effort between 2 groups of people who are doing the same procedure, which isn't very common in cardiology. There is data that has been published that outcomes between ICs and EPs are comparable. What probably matters for sure is the experience and expertise of that individual person, but this concomitant option really has kind of changed that equation a little. Do you have an opinion about if these procedures should be done by 1 EP, 2 EPs, IC, or IC/EP combo? How do you see that at most hospitals? 

Christopher Ellis, MD: My guess is that for concomitant, I think most patients are going to get treated by the person doing the ablation, and that's going to be the EP. I suppose the question is that in some sites where there are very high-volume, experienced ICs for the appendage closure, should they be doing the ablation? So, I mean, we think of it as the other way around. 

Bradley Knight, MD: Well, in the OPTION trial, only 40% of the patients in that study that got both had it done at the same time. So, it was a good proof-of-concept study, but it doesn't preclude the option of doing them in a staged manner, which might happen to some of these hospitals. 

Christopher Ellis, MD: I bring that up a lot. I really try to drive it home that these never have to be done at the same time, it can always be staged. So, if you're having a bad day and this ablation is not going well, bring them back for their appendage closure later. Or, if the anatomy is really swirly and you want to think about a different device, you don't have to try to force the issue. I think that's a very important point. 

Bradley Knight, MD: After doing appendage closure now for 15 to 20 years, it's really interesting to see where we are right now. The devices are far better, the procedure is better, and everybody is more experienced. But if you have to sit down and write recommendations, you realize all the unanswered questions. 

Christopher Ellis, MD: Yes, and there are probably many more that we didn't touch. 

Bradley Knight, MD: Well, thank you for doing this. I appreciate it. Good luck. 

Christopher Ellis, MD: Thanks.

The transcripts have been edited for clarity and length.