Valve Disease: When is the right time to intervene?
Steven Nissen, MD, sits down with Marc Gillinov, MD, Chairman of the Department of Thoracic and Cardiovascular Surgery and Brian Griffin, MD, Section Head Cardiovascular Imaging to discuss timing of heart surgery, one valve at a time – the differences between aortic and mitral valves and regurgitation and stenosis. Changes in diagnostic imaging techniques, surgical and interventional options, as well as looking at outcomes data have changed the way we look at these patients and timing of intervention.
Valve Disease: When is the right time to intervene?
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Dr. Steve Nissen: I'm Steve Nissen, and I'm here with two extraordinary experts in valvular heart disease, Dr. Brian Griffin, who is a cardiologist, and Dr. Mark Gillinov, who is a cardiac surgeon. We're going to talk about timing for valve surgery. So, let's take it one valve at a time. Let's talk about the aortic valve. How do you make a decision in the contemporary era when somebody is ready to have an operation? It used to be a little easier than it is now. We didn't have so many tools. We've got a lot of tools now Brian. Maybe you can start that off.
Dr. Brian Griffin: So, I think it really depends on what the underlying problem is, but let's start with aortic stenosis. It used to be that we waited and waited and waited because results weren't that good. In fact, Gene Braunwald said many years ago that the leading cause of sudden death in aortic stenosis was unnecessary surgery. That's not true anymore. The results with surgery have gotten so much better. Results with TAVR have got so much better, and there's increasing evidence that waiting too long may lead to irreversible changes in ventricular function. So, I would say that our threshold to intervene is still symptoms, but also looking at left ventricular function, not just ejection fraction, but things like strain, B-natriuretic peptide and we start to see that there's a blip. The strain is going down, say below minus 16%. BNP is going up. That's something that I look at in terms of making a decision.
Dr. Brian Griffin: If I have somebody who's younger, and I'm a bit worried about that they have really severe aortic stenosis and claim they're asymptomatic, I will put them on a treadmill. And again, we've seen and we've shown that if they can't achieve their age and gender matched cohort, if they can't do as well as somebody of their age and gender in terms of exercise testing, they're at risk longterm if they don't have surgery. Surgery is, or valve replacement, is quite protective over the long haul, even in people who have evidence of impaired LV function to start with.
Dr. Steve Nissen: The valves gotten better Mark?
Dr. Mark Gillinov: The valves are definitely better. We have two broad categories of valve replacements, and aortic stenosis is always a valve replacement, not a repair. The two broad categories are biological or bioprosthetic valves, those tend to be cow or pig, and mechanical valves. The current generation of the biological valves is very durable. People over the age of 65 will usually get one valve, and it will more often than not last a lifetime.
Dr. Steve Nissen: Last a lifetime.
Dr. Mark Gillinov: And the mechanical valves are good. The issue with mechanical valves is most people don't want to be on longterm anticoagulants.
Dr. Steve Nissen: And they have to take warfarin. They can't take these newer anticoagulants, so that requires all the monitoring and so on. So Brian, does this improvement in valve technology, and I'm going to ask you a little bit later about surgical technique, but has this had any influence on timing?
Dr. Brian Griffin: It has. I think we're ... even the guidelines, which tend to lag practice a little bit, but even now suggest that it's reasonable to go ahead and intervene in aortic stenosis in somebody who has very severe aortic stenosis if you assume that ... if the center where you're going to do the surgery, or the procedure has a mortality of 1% or less. I'm happy to say that our mortality for AVR in all comers, isolated AVR, is about 0.5%. So, in somebody who has critical aortic stenosis, who isn't symptomatic, it's now considered reasonable to proceed to an intervention, whereas before it was not. So, I think it really has changed how we approach things. Now, we didn't talk about aortic regurgitation, which is actually in some ways more interesting, and we have had some recent data that suggests that the data that was available for the guidelines before was from the 1980s. We have looked at about 1300 patients, which is about four of five times the magnitude of data that was previously available, and there is certainly a suggestion that waiting until the ventricle gets really big and dilated may not be such a good thing in the current era.
Dr. Brian Griffin: Again, I think we're beginning to see the same thing. Interventions are safer than they used to be, and waiting and waiting and waiting until you get these massive changes in ventricular size and function, structural changes in the heart, which may be very slow to resolve, even after a very successful procedure. So, I think if I were to take the global picture of everything in valve disease, as the procedures have gotten better, mortality has gone down. We've gotten better valves. The threshold to intervene keeps on lowering. And so if you had an absolutely perfect valve, why wait, I suppose? We don't have absolutely perfect valves, but they've gotten very good, and as Mark points out, in older people, biological valves are very durable and are very successful. So, waiting until somebody's kind of just one inch away from falling over the cliff may not be the way to go, and the guidelines are beginning to reflect that view point.
Dr. Steve Nissen: So, what are the surgical innovations that have kind of moved the needle in terms of lower mortality, better outcome, I presume shorter hospital stay? What are you doing that you didn't do a decade, or two decades ago?
Dr. Mark Gillinov: For aortic stenosis, of course, it's almost always, virtually always, a valve replacement and our techniques for cardiopulmonary bypass, and the operative conduct have improved, so risk has gone down. Aortic regurgitation though, is special. The person with aortic regurgitation needs a cardiac surgeon who is capable of repairing the valve. If the person, patient, has aortic regurgitation, and the valve is not calcified, we have experts who can repair those valves, and we are talking about biological valves and mechanical valves, pig valves, cow valves. What I really want is my human valve.
Dr. Steve Nissen: There's no valve like your own valve.
Dr. Mark Gillinov: There's no valve ... there's no place like home. There's no valve like your own valve. So, if you've got pure aortic regurgitation, or a patient with that, and no calcium on the valve, you need a surgeon who has the likelihood of repairing that valve. That's your best option.
Dr. Steve Nissen: So, what fraction of the valves, now that you're operating on the aortic valves for aortic regurgitation, are you able to repair?
Dr. Mark Gillinov: It's probably going to be about 20%, 25%.
Dr. Steve Nissen: So, it's not a majority?
Dr. Mark Gillinov: Not a majority, but I think the majority of those that could be repaired are replaced because few surgeons have the experience and expertise to repair these valves.
Dr. Steve Nissen: So, let's turn for a moment then to the mitral valve, because both of you, and currently you Mark obviously spend a lot of your life fixing mitral valves. The timing considerations for mitral valve disease, how have they evolved in recent years?
Dr. Brian Griffin: So, similarly I would say that there's an increasing realization that there's a price to pay for waiting. In some ways, it's more problematic with the mitral valve in that symptoms are quite late, and they ventricle has remodeled, often compensates very well, but there are subtle changes that are occurring at a molecular level that we don't necessarily detect with our current imaging techniques. What are beginning to see is, again, that some changes in left ventricular strain, some changes in BNP, and we found that those are predictive of poor longterm survival, even despite surgical intervention. So, waiting until bad things have started to happen may not be such a good idea.
Dr. Brian Griffin: So, the simple way to consider mitral regurgitation is if it's a primary problem, that's so much as a prolapsing valve, and the regurgitation is really severe, and it looks like the valve has a high likelihood of being repaired, and with Mark's kind of abilities, that's in virtually everybody these days, which I'm happy to say, as long as they don't have a lot of calcium on the valve then waiting is probably not such a good idea. Now, patients may opt to wait, but there isn't a reason to hold off doing an intervention.
Dr. Brian Griffin: It's different though, or maybe I'll turn this to Mark because he did some of the clinical trials in this area in ischemic MR, where how we approach ischemic MR is different than it was say five, seven years ago, often really based on the information that Mark and his colleagues gleaned in those clinical trials.
Dr. Steve Nissen: So, let's take first things first then. First of all, obviously this rationale for operating earlier in part is due to the fact that you now do most of these patients minimally invasively. Any sense of what fraction of the ... assuming it's isolated mitral valve disease, what fraction of these patients are you able to repair?
Dr. Mark Gillinov: For isolated mitral valve disease, say prolapse, we can repair about 99% of them, and of course the goal is to get that valve back to normal. Just like aortic valve, your own valve is the best valve, but the mitral valve is fundamentally different because we can almost always repair the mitral valve. Not everyone is a candidate for a robotic or minimally invasive approach.
Dr. Steve Nissen: I was going to ask you that next. So, who gets these minimally invasive, robotic procedures and who doesn't?
Dr. Mark Gillinov: The people who are qualified for that go through an algorithm, or we put them through an algorithm, where we look at their CT scan, their echo, their cardiac cath, make sure that they're good candidates, meaning that they don't have calcium in the valve, as you brought up. They have a valve we can repair. They only need a mitral valve operation. We can put them on a heart/lung machine through the femoral artery and vein.
Dr. Steve Nissen: So, they have to have not so severe peripheral vascular disease?
Dr. Mark Gillinov: Right. Peripheral vascular disease would be a nonstarter, and better just to have a regular procedure. Our algorithm is very selective. It leads us to do maybe a couple hundred robotic mitral valve operations per year. But, the results validate the algorithm. Our operative mortality is 1:2000.
Dr. Steve Nissen: Yes, and they go home quickly?
Dr. Mark Gillinov: Today is Friday? People I operated on Monday are on their way out today, so four days there about.
Dr. Steve Nissen: Yeah. It's really come a long way. Listen, I'm old enough to remember the era of cardiac surgery when it was quite an ordeal for patients, for any valvular operation, and I hate to tell you this, but I'm old enough to remember when there were a lot of Starr Edwards ball and socket valves.
Dr. Mark Gillinov: Those worked.
Dr. Steve Nissen: They worked, but they were pretty crude by comparison to now.
Dr. Brian Griffin: Some of them are still in.
Dr. Mark Gillinov: Yes.
Dr. Steve Nissen: Yes, some of them are still in. Now, let's turn to this issue that Brian raised about ischemic MR. Tell us what the thinking now is about what to do, when to do it, timing particularly.
Dr. Mark Gillinov: The surgical role in ischemic MR is likely extremely limited. If you are operating for ischemic MR, the repair is unreliable and we would tend to favor replacement with a bioprosthesis, biological valve. But of course, the COAPT trial suggests a remarkable benefit to reducing the MR with a clip.
Steve Nissen: Yeah. And so you think that's really been a game-changer?
Dr. Mark Gillinov: Yes, surgically we recognize that these were relatively high-risk patients, repairs for whatever reason were not durable, and if they can get a less invasive procedure that appears to have a surprisingly large benefit, but it's there in a randomized controlled trial, that's the way to go.
Dr. Steve Nissen: You ever stage these things? You ever have somebody who has this and you say, "They're kind of pretty sick right now, but I'm going to go ahead and do something like a mitral clip," and then bring them back when they're a little bit more stable and then maybe do something more definitive? Does that happen?
Dr. Mark Gillinov: Uncommonly. Uncommonly. We had a patient last weekend in the CC though with mitral valve prolapse, unstable, and recommended a clip for that.
Steve Nissen: Yeah, but you might go back later and do something else?
Dr. Mark Gillinov: If necessary, yes.
Dr. Steve Nissen: Yeah. Okay. Well, this has been great. You know, I really had a great opportunity to talk to two people who spend much of their waking hours thinking about who to operate on, what operation to do, and I have to say that I'm very proud of the fact that as a result of the collaboration, good decision-making upfront by the cardiologist and terrific surgery, we just have amazing outcomes for these patients. It's a huge advance.
Dr. Mark Gillinov: Yes.
Dr. Steve Nissen: Thank you for watching. I'm Steve Nissen for the department of cardiology.
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