Daniel Lustgarten, MD, introduces us to the WATCHMAN Device, an alternative to traditional blood thinners to be used as a way to prevent clots from forming. Listen to the interview or read the transcript below.
UVM Medical Center: It turns out the appendix has a little competition when it comes to being a part of the body that doesn’t do much good but can do a lot of harm. I’m talking about the small pouch attached to the upper left chamber of your heart. For most people it isn’t anything to worry about, but if you’re one of the six million Americans with an irregular heartbeat, blood can collect in this pouch, form clots, and potentially travel to your brain causing a very bad stroke. What can be done about it? Well the common treatment is blood thinners, but they can be complicated to use, and come with a high risk of bleeding. Many patients simply can’t use them at all.
Fortunately the FDA has approved a device that closes off the pouch, eliminating the need for thinners. Researchers at The UVM Medical Center and Larner College of Medicine participated in the clinical trial of what’s known as the WATCHMAN Device, and I recently spoke to the leader of that team, Dr. Daniel Lustgarten to learn more about this new option. He’s an electrophysiologist at the UVM Medical Center and a professor at the Larner College of Medicine. I started by asking him to describe who will benefit most from the WATCHMAN Device.
Dr. Lustgarten: The patients who are affected and who are potentially candidates for this approach to preventing strokes are patients with an arrhythmia, which means an abnormal heartbeat called atrial fibrillation. There are several different types of arrhythmias that affect the heart. By far atrial fibrillation is the most common. It is a problem that each of us, as we get older and older, are at higher and higher risk to develop. In essence what it is, is normally the two top chambers of the heart need to be coordinated with the two bottom chambers. That coordination is lost in patients that have AFib due to the fact that when they are in atrial fibrillation, the atrial chambers are beating chaotically and continuously.
Instead of there being a nice organized little beat, an impulse that begins and goes through the heart and resets itself, there is no resetting in the atria, so there’s continuous electrical activity. The reason why patients are at risk for stroke who have atrial fibrillation is due to the fact that during atrial fibrillation, the atrial chambers no longer contract. They are in essence just quivering. The pouch of tissue that you just referred to, the left atrial appendage is an extension of tissue, a little walled off room, if you will, that communicates with the larger body of the left atrium that during AFib becomes a place where blood can essentially pool. Pooling blood can allow a clot to form.
UVM Medical Center: That’s because the heart isn’t squeezing the right way, so there’s blood left in there, and that’s what gets into the appendage.
Dr. Lustgarten: Correct. The appendage is continuously filling with blood and along with the rest of the atrium, squeezing. In addition to that, when the appendage in the left atrium is no longer contracting, and blood is just sitting in there, it’s no longer flowing with the main body of the left atrium. Hence a blood clot can form where that blood is pooling inside that pouch.
Blood thinners, drugs like Coumadin, also called Warfarin, or some of the newer drugs that are very similar in terms of their ability to prevent clots from forming – like Rivaroxaban or Eliquis – these are drugs that inhibit the ability of the blood to clot, the advantage of which is that it lessens the likelihood of a clot forming in that pouch. The disadvantage, the tradeoff of these drugs is that it impairs your ability to clot, which means by definition your risk of bleeding is now higher. It is a known, well established tradeoff between the stroke associated with AFib versus the potential of bleeding because of the drug that’s trying to prevent that stroke.
In most instances, that’s a reasonable trade off. It is reasonable because most bleeding is fairly readily fixable. Most of the strokes that are caused by AFib are very bad strokes, very difficult to treat, and often lethal, actually. The WATCHMAN Device is in essence a mechanical alternative to those blood thinners at trying to prevent those clots from forming, and getting out into the main body of the left atrium. It literally is a parachute shaped plug that seals off the appendage so that it no longer communicates with the main body of the left atrium.
The key thing to appreciate in this is that the device is no better at preventing strokes than the standard of care, which is blood thinners like Coumadin. It’s as good in terms of preventing the strokes from occurring. It is clearly better at preventing or limiting the bleeding risks of the drugs that we use over the long term. The key point here is that a potential candidate for this device has to be somebody who can tolerate at least some period of time on a blood thinner.
UVM Medical Center: Blood thinners as I mentioned are kind of a pain, right? I mean there’s a lot of calibration you have to have, the right dosage, the side effects and so forth. In your view for patients this is preferable?
Dr. Lustgarten: It is true that blood thinners have significant negatives associated with them. The gold standard of drug therapy has been this drug Coumadin or Warfarin which was actually originally designed as a rat poison. The first patient who actually took Warfarin was President Dwight Eisenhower, the very first person to be treated with this method.
UVM Medical Center: No kidding, wow.
Dr. Lustgarten: It’s true. The issue with Coumadin is that it’s a drug that has to be tailored to the given patient. Everybody responds to it differently. They require different dosing patterns. Whether or not the level is too high or too low varies all the time. It’s very complicated and kind of messes with people’s quality of life because of that, on top of which they’re at high risk for bleeding. The newer agents that are to some extent replacing Coumadin are much easier to take. You don’t have to get tested. The biological effect is much more consistent from person to person, but you still are left with the problem of bleeding, and there’s also a problem of expense. Those drugs are very expensive. Often that is an issue.
In terms of the ability to prevent a stroke, the WATCHMAN Device is just as good as those, as I think we already mentioned, but not better than. It is an expensive device, and procedure, and hospitalization. The patient has to stay one night in the hospital. Because of those expenses and also because now it’s a procedure – and there are risks associated with procedures – Medicare has mandated that the patient population that we’re targeting are people who for one reason or another can’t tolerate long-term blood thinner as a strategy. Most commonly those are people who have problems with bleeding when they take these drugs. It can also include for example patients who are maybe elderly, who are unsteady on their feet, and at risk for falling, who are at particularly high risk for bleeding because of blood thinners.
Related to that is the fact that you know if you take 100 patients with AFib who should be on a blood thinner in the United States today only 40 to 50 of those patients are actually on a blood thinner, so there is a huge percentage of patients who are not getting appropriate therapy, and very likely a large chunk of that patient population are patients who could be well served by this device. There are other patients who are remaining on these drugs who have problems with bleeding, and they are also excellent candidates for this device. There has to be a compelling reason to switch or offer this as an alternative therapy to blood thinners.
UVM Medical Center: You’re listening to Dr. Daniel Lustgarten. He’s an electrophysiologist at the UVM Medical Center, and a professor at the Larner College of Medicine. We’re talking about a new device to help prevent strokes called the WATCHMAN Device, and it is something that we participated in doing clinical trials on, and I want to touch on that. What was that whole process like, and how do we get involved in all that?
Dr. Lustgarten: Back in 2012, I was approached by the company that was making this device to participate in a controlled randomized trial with at least part of the intention of that study being looking at the safety of this device in a new program’s hands. Prior to our getting involved there had already been a study done called PROTECT AF, and that study demonstrated that the device did at least as well, in fact did a little bit better than, blood thinners at preventing strokes. The problem with that study is that there are many complications associated with the procedure itself.
Most of those complications were relatively trivial, meaning that compared to a stroke they weren’t so bad. That being said, some of those complications were strokes. Most of them were due to bleeding around the outside of the heart which is a risk whenever we do any kind of procedure inside of the heart, you can get bleeding called a paracardial infusion. The FDA wasn’t happy with the safety signal of that study. Now interestingly, if you look at that study, most of the events occurred when the study was just starting. There was a learning curve that was evident even within that context, or even within that trial. The FDA still was concerned, and they wanted another study proving that people who are just starting to do this could learn it quickly and safely.
That was called PREVAIL and that’s when we got involved. I believe our first implant was February or March of 2012. We were actually the highest new enrolling center in PREVAIL, so we played a very significant role in helping the FDA determine whether or not a new center like ours could learn to do this safely. Indeed, our Center did very well in that regard, but in addition to that, following that there was a period of time that the FDA allowed more patients to get the device. It was called a Continued Access Registry. We participated in that, and in the course of all of this there were subsequent meetings that the FDA called down in Bethesda, Maryland, and at both of those meetings, patients of ours actually presented their experience. At the third and final meeting I actually joined one of our patients and also presented to the committee. We played a pretty significant role in helping to get this thing across the finish line.
UVM Medical Center: I don’t think we mentioned that this is all done through a catheter, which is amazing because this is a fairly sizable device, and somehow you guys have figured out how to shrink it inside a little catheter tube. This leads me to ask you if there’s been an expanded use of catheters, and not just in cardiology, in other ways. Are you expecting that to continue?
Dr. Lustgarten: That’s a good question, because I think it is very expensive, and it’s an arduous process to take these devices, design them, engineer them, get funding for all of that, and then get funding for the studies, which are enormous studies that have many, many millions of dollars of costs associated with them. There is an arduous process, and that process is, if anything, getting more and more difficult. On the other hand there is higher and higher demand for us to leverage the technologies that we have at our disposal to do more and more, in a safer and safer fashion, and in a more effective fashion.
There are all sorts of things that feed into how this will evolve. If we start backing away from supporting medical research and biological technology development, well then we will sort of reach a glass ceiling if you will with this. It really depends on how much money our society decides to allocate to do this. That being said, there’s no question that in all of our fields, our respective fields, we are doing things on a smaller and smaller scale, and a less and less invasive scale. Yes, I would see the future of medicine really is miniaturization, and minimizing the invasiveness required to do this or that.
Whatever the case is in other fields, there’s no question that right now in cardiology with respect to heart valves and in my field with respect to cardiac devices for pacing, and defibrillation, and for preventing strokes like the WATCHMAN, you know there’s enormous gobs and gobs of new technologies that are right on the cusp.
UVM Medical Center: Do you guys expect to be involved here at the UVM Medical Center with trialing some of that?
Dr. Lustgarten: For sure. By virtue of the fact that we played such a significant role with WATCHMAN – and in parallel with Dr. Dauerman and his program with the aortic valve replacement which I’m sure you guys have discussed – our Center has identified itself as one that is very capable at participating in these studies and driving these technologies forward. I’ve already been approached by other companies for looking at alternatives to WATCHMAN and things like that. For certain we are going to continue to participate in this process, I would anticipate at an accelerated rate, in fact.
UVM Medical Center: Well I’m sorry to say we got to leave it there, but congratulations on your involvement with WATCHMAN. We’ll be back to talk to you about other devices and what you’re up to, to treat these diseases in the future, I’m sure.
Dr. Lustgarten: Great. Thank you very much Michael. I appreciate the opportunity.
UVM Medical Center: My guest today has been Dr. Daniel Lustgarten, an electrophysiologist at the UVM Medical Center and a professor at the Larner College of Medicine.