Left Atrial Appendage Closure: Preventing Strokes in Patients with Atrial Fibrillation
Oussama Wazni, MD, Section Head, Cardiac Electrophysiology and Pacing and electrophysiologist Walid Saliba MD discuss atrial fibrillation stroke prevention, and the role of left atrial appendage occlusion: outcomes noted at Cleveland Clinic, what to do in patients that are unable to take Coumadin due to risk of bleeding, FDA indications, new technology available and the role of LAA occlusion in light of the newer anticoagulants.
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Left Atrial Appendage Closure: Preventing Strokes in Patients with Atrial Fibrillation
Podcast Transcript
Announcer: Welcome to Cleveland Clinic Cardiac Consult, brought to you by the Sydell and Arnold Miller Family Heart and Vascular Institute at Cleveland Clinic. In each podcast, we aim to provide relevant and helpful information for health care professionals involved in cardiac, vascular, and thoracic specialties. Enjoy.
Dr. Oussama Wazni: Hello, I'm Oussama Wazni. I'm the section head of electrophysiologists at the Cleveland Clinic. Here with me today is Dr. Walid Saliba. He's the Director of the EP lab and also co-director of the AFib Stroke Prevention Center that we founded here at the Cleveland Clinic a few years ago. And, we're here to talk to you about left atrial appendage closure device. Without further ado, we'll start.
Dr. Saliba, can you just tell us a little bit about the background of why you think this technology or this aspect of patient care is as important as we found it to be?
Dr. Walid Saliba: Sure. As you know, atrial fibrillation increases the risk of stroke significantly, around five times increased risk of stroke with patients who have atrial fibrillation. We also know that most strokes that occur in patients with atrial fibrillation, the clot is attributed to a clot in the left atrial appendage, and therefore, it is very reasonable to think that if there is some kind of technology that allows us to block the left atrial appendage, that we would presumably decrease the risk of stroke. The studies that were actually done previously in the surgical literature, even though they were not a randomized studies, there were some points that this might be true. And finally, with the advent of the left atrial appendage occlusion device, the Watchman device, there were several studies that were done that actually proved that theory to be somehow right.
We have, at our disposal so far, several studies that took patients with atrial fibrillation, at high risk of stroke, as judged by certain characteristics that they have, based on the CHADS VASc score or the CHADS score. And these patients were randomized into two, two, one fashion to either receive the Watchman device, left atrial appendage occlusion, versus Warfarin. So, therefore, these patients had to be able to take oral anti-coagulation, which is very important for our discussion later.
All the studies showed that the Watchman device was not inferior to Warfarin in terms of its efficacy in decreasing the combined endpoint of stroke or systemic embolization. And also, if you take the totality of the trials that was done, you can see that there was a significant, actually, reduction, not only in the all cause of stroke but also in cardiovascular mortality, which was mainly driven by a reduction of risk of bleeding and bleeding events.
And then, which is essentially logical to think about, because if patients have the Watchman device to decrease the risk of ischemic stroke, therefore will not need to take long term anti-coagulation, which is the taboo of the old anti-coagulants. Then they will have a reduction in the risk of hemorrhage.
Dr. Wazni: So, who are the indicated patients today? FDA indication today?
Dr. Saliba: So, the FDA indication, which I think is a reasonable wording because they had to base their indication on the kind of patients that were enrolled in the studies. Patients who have atrial fibrillation, who are at increased risk of stroke based on their CHADS VASc score, which is two or more, who are able or judged by their physicians to be able to take oral anti-coagulation. And, this is also subject for some controversy here. But, they have an appropriate rationale to seek non-pharmalogical alternative to that reduction of risk of stroke, taking into account the risk and benefits of these alternatives.
Dr. Wazni: Can you tell us a little bit about how you developed the program at the Cleveland Clinic, specifically for stroke prevention and atrial fibrillation patients.
Dr. Saliba: We realized early on, during the development of such a center, that most of the patients who will be seeking this kind of a therapy are the patients who do not or cannot take oral anti-coagulation. These are the patients who have had a history of bleeding yet they are at a high risk of stroke and they need to have some kind of a prevention for stroke. These are the patients who are potentially bleeders, who because of certain characteristics, being their job, their occupation, or certain medical conditions that they have, are at an increased risk of bleeding, but they haven't bled yet.
With this in mind, we knew that those kind of patients that are of concern in these situations are the patients who had either bleeding in their head, bleeding in their gastrointestinal system, bleeding in the genitourinary system, and therefore we went ahead and partnered with our colleagues in the neurovascular institute, in the gastrointestinal institute, because we wanted to build more of a collaborate, multidisciplinary approach to this kind of a problem. So that when a patient comes to us, instead of having flip flopping from one clinic to another, we'll have a streamlined one stop approach. So that when they come to us, they see us, we determine the risk of bleeding, we determine the risk of stroke. Based on the risk of bleeding, we send them to that clinic so that our colleagues will help us in determining what is the appropriateness and the risk of initiating anti-coagulation on the short term for these patients. Because, in order for us to put that device in, these patients need to be on anti-coagulation around 45 days after the procedure.
Dr. Wazni: Those are the patients, basically, who were contraindicated or were not included in the studies. Those are patients who already had a bleeding episode or are at very high risk for having bleeding. Can you tell us about our experience, or your experience, and those kinds of patients?
Dr. Saliba: That is a very important question, because if you look at that group of patients, you can see that these are not the patients that typically were enrolled in the studies. But, these are the patients who we think would have the most benefit, or would have the most benefit, from a left atrial appendage occlusion device. So, most of the patients that we have considered in our practice here, are patients who actually have had either an intracranial bleed or subdural hematoma, or patients who had GI bleeding. So, these are patients at high risk of bleeding, definitely. And then, we asked our colleagues, "Is it okay to anti-coagulate these patients for six to seven weeks, only to be able to put that device in?" And, there was a lot of talk, and there was a lot of give and take. It's an experience for them as much as an experience for us.
To our surprise, and very pleasantly so, those patients, we were able to give them intermediate anti-coagulation. We have approximately now 50 patients and we published our data on 30 or 40 of these patients. We were able to get them on anti-coagulation, put the device in, get them off anti-coagulation, with successful device implant in all of them. Most importantly, we have not had any problems with bleeding in any of these patients except for one patient who actually had a traumatic bleeding after he stopped anti-coagulation.
Dr. Wazni: Yeah.
Dr. Saliba: That was an eye-opener for us, that this is something actually that is feasible, that this is something that we will have to reproduce in larger clinical trials.
Dr. Wazni: This is very reassuring. I just want to emphasize that these are the patients who probably get the most benefit from left atrial appendage closure, because we're able to close the appendage, decrease the risk of stroke, while at the same time not putting them at high risk for long term anti-coagulation and bleeding in the future.
Dr. Saliba: Because, the alternative is that if you're not going to give them anti-coagulation and you're going to deprive them the luxury of having that device in, then their risk of stroke is quite significant.
Dr. Wazni: I think, actually, that our group has been the major leader in this kind of approach for these patients. How about the patient ... So, the problem with the studies, and that's why people are ... I don't want to say resistant, but hesitant to implant the device as primary therapy, and not in bleeders, is because the device was not superior to Warfarin in terms of decreasing the risk of cerebral ischemic stroke or embolism. But, I know that you just shared with me that you have some data on some very high risk patients with a high CHADS VASc, so can you tell us about that group of patients?
Dr. Saliba: We looked at ... We have, so far for the past few years, we've implanted in excess of 300 such devices. So, if we pull out the patients who have a high risk of stroke, these are patients who have a CHADS VASc score of 5 and above. And, you look at ... Two thirds of these patients have had a history of stroke or TIA, so we're talking secondary prevention now of stroke.
If you look at what happened to those patients after we've implanted that Watchman device ... First of all, we were able to implant the Watchman device in all of them, and then when you follow them up, their risk of stroke, after they had gone through the 45 days of going through the anti-coagulation and stopping them, is only 2.8%. If you compare that to a historical control with the CHADS VASc of five to six, their risk of stroke or systemic embolization is in excess of 12%. With Coumadin Warfarin alone, assuming it's 70-80% reduction risk of stroke, that risk was down only to 4%.
So, those patients who've had a stroke before, high CHADS VASc, very high risk, who have had also probably bleeding problems, instead of feeding the lamb and leaving them alone, we were able to get them down to a 2.8% risk of stroke, with the Watchman device.
Dr. Wazni: This is very reassuring, meaning and showing that actually the therapy works in decreasing the risk of ischemic stroke or embolization. That was the concern we had from PROTECT and PREVAIL, because in those studies, it was just equivalent to Warfarin without being superior to Warfarin in decreasing ischemic stroke. But, based on the very high risk patients, our cohort, it looks like it does work even better in the higher risk patients.
Dr. Saliba: Exactly, and if you look at the sum of the subgroup analysis in PROTECT, looking at patients who've had prior history of stroke, so those secondary prevention patients, it did, even though it was not a pre-specified end point. But, it did decrease, actually, the risk of ischemic stroke in those patients, which is very important. Now, one more thing that we have to add for those very high risk patients, who also have high risk of bleeding because these are the kind of patients that we have implanted, these patients in the community might be left alone.
Dr. Wazni: Yes.
Dr. Saliba: And, when you are faced with the risk of bleeding with intermediate term anti-coagulation, which is very low in our experience, versus the risk of stroke if you are not taking anti-coagulation, it becomes a no brainer that this is the way that things need to be actually moving.
Dr. Wazni: I know also that there was a new iteration of the Watchman device that has been in clinical trials. Can you tell us a little bit about it and how is it different from the original Watchman?
Dr. Saliba: The original Watchman device has its own limitations, mostly size limitations. If the appendage is too small, the current available older Watchman devices cannot actually be used for these appendages. Or, if the anatomy of the left atrial appendage, whereby the os is too large and the appendage is too short, the currently available Watchman device, approved Watchman device, cannot be used. And therefore, there's a new iteration of the Watchman device where there are certain changes, such as now you can use that newer device for smaller appendages or for short appendages or for larger os appendages.
And also, the technique to put it in place is probably more comfortable for physicians to use because it doesn't have those feet at the tip. It has a closed end at its tip, and therefore you can form a little bit of a ball and push it. It gives you also more flexibility in terms of implant technique. With the older device, if you put it proximal and you're not happy with that, then you'll have to retract the device, throw it away, get a new device in its place, whereas, that new device allows you to partial retract it and then push it forward. So, more flexibility in terms of the implant procedure for the implanting physician.
Dr. Wazni: Excellent, and how about the Amulet device? I know it's in studies. Where is that going, you think?
Dr. Saliba: Well, there are a lot of other devices that are going to be in clinical trials. And now that the Watchman is approved, it's easier to get those devices on the market. All they have to do is actually compare it to the available Watchman de jour. It is in clinical trial. We are part of this clinical trial. It does have its advantages in terms of implantation, ease of implantation. We'll have to wait for the major clinical trial in the US to see what is the outcome going to be, but we know from clinical experience in Europe that there is the efficacy and the safety of that device might be comparable to the available Watchman, but this is something that we will need to actually establish here in the US.
Dr. Wazni: And how about the safety profile of our own experience with Watchman at the clinic so far?
Dr. Saliba: We are very excited about our experience because we have had an excess of 300 implants. Most importantly, because there was a concern with the initial experience with the PROTECT AFib, that there might be a high risk of adverse outcome at the time or periprocedurally. We have not had any device embolization with the Watchman.
Dr. Wazni: That's...
Dr. Saliba: We have not had any peri device implantation strokes. We have had one case of delayed pericardial effusion without tamponade that we elected to drain percutaneously. And, our experience, despite the fact that we have probably four of us who do these kind of implantations, have had very good experience and not had any major problems.
Dr. Wazni: That is actually impressive, because even comparing to the control studies, the risk of effusion was much higher than one in 300. It was probably more around 1 to 2%, in the later iterations, actually, of the studies. So, basically what we're saying is that it is very effective in decreasing the risk of ischemic stroke and definitely decreasing the risk of bleeding, and it has a very good safety profile. So, what would it take for you, in your mind, for us to start offering left atrial appendage closure as first line therapy without having the patient having to have an intercranial hemorrhage before we've offered them this device?
Dr. Saliba: That is a very important question. We have always to remember that the major clinical trials that were done with the Watchman device were against Warfarin. And, Warfarin has its potential problems, in terms of time and therapeutic range, in terms of patient not discontinuing the medication. So, with the new kids on the block, which are the newer anti-coagulants, which have proven, actually, some superiority in certain respects to Warfarin. The question is, what is it going to take for us to suggest the device therapy versus newer anti-coagulant therapy? So, we'll have to see how these two actually compare, because I think that the main alternative treatment option now that is available for stroke prevention, is with the increasing use of the newer anti-coagulant versus the Watchman.
Also, we have to keep in mind what kind of patient population was included in the study for the Watchman. These are patients who their highest risk of stroke is really from the left atrial appendage, so these are patients who do not have aortic arch atheromas, do not have carotid disease. LV function is actually more than 30%. They do not have LV thrombus. So-
Dr. Wazni: Valvular...
Dr. Saliba: They do not have valvular heart disease. There's still a large patient population who are at the increased risk of stroke, who do not fit, necessarily, the Watchman inclusion criteria. So, how much do we extrapolate and how many patients do we include just by clinical practice? It's something that real fine data is going to be able to-
Dr. Wazni: It seems to me that we may need randomized study of Watchman versus the new oral anti-coagulant at some point.
Dr. Saliba: So, I think that it's very important to think now about a Watchman in two different environments. One is, where is the place of the Watchman in the arena of newer anti-coagulant, and more importantly, where's the place of the Watchman with the growing atrial fibrillation ablation population?
Dr. Wazni: Very good. Any final thoughts on this therapy?
Dr. Saliba: We are very excited about the availability of this therapy. I think it is definitely a practice changing therapy, and it gives us a lot of room for future research. There's going to be a lot of newer devices that are going to be on the market that we're also going to be involved in evaluating, and I think the future is bright and exciting, to see how things are going to lead us.
Dr. Wazni: And, in my practice, I have to say the patients are very comfortable with the therapy, and very satisfied with it. They come back and thank me for the improvement in quality of life because now they don't have to worry about taking an anti-coagulant that may cause bleeding and repeated visits to the emergency department. So, I think it's a new era in stroke prevention, and I think it gives us a lot of new options to treat those very high risk patients, whether it's ischemic stroke or with bleeding.
And at that, I thank you very much for joining me, Walid, at this-
Dr. Saliba: Thank you, it's a pleasure.
Dr. Wazni: ... Podcast. Thank you very much.
Dr. Saliba: Thank you.
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