Jim Cissel: Before we talk about the traditional open heart surgery procedure and the new TAVR procedure, let's talk about the valve disease itself. What does it involve? What are the symptoms? What are the problems?
Dr. Rizik: Aortic valve stenosis is a closing off of the aortic valve. If you look at some of the images we have, the aortic valve is a one way door out of the heart. You can see hear a normal aortic valve that opens wide open and it is a very thin structure. You can see that with aortic valve stenosis the valve leaflets begin to thicken and they become immobile, in other words they don't open all the way. This can lead to a lot of symptoms such as chest pain, shortness of breath and fatigue for patients. The older you are the more likely you are to develop aortic valve stenosis. Traditionally, the therapy for aortic valve replacement has been surgical. It is still the gold standard, and what it requires is for the surgeon, the open heart surgeon, to saw the chest open, spread the ribs and the muscles, and what the surgeon does is he cuts out, or removes, he extracts the old aortic valve and can sew in a metal valve or a tissue valve, an aortic valve prosthesis. In the latest procedure, TAVR, we can create a minimally invasive incision into the groin area. We can then pass a transcatheter valve, mounted on a balloon, up to the diseased valve, and once the valve, mounted on the balloon, is dilated into place the balloon is then deflated and removed leaving a new valve prosthesis, a new aortic valve in position. Looking at a more complete assessment, we make an incision through the leg and through the femoral artery, a wire is passed up the aorta and then the next portion of the procedure is to actually place a balloon, similar to what is placed in balloon angioplasty of coronary arteries. Then that balloon is dilated and dilates the valve to create an opening if you will to place the transcatheter valve, or to place the new valve prosthesis. The transcatheter valve, which is mounted on a balloon, is then passed through the old valve or the native valve as we call it. The valve is then dilated on the balloon, the balloon is then deflated and retrieved, and left in place is this new valve prosthesis. Again this is very different, and far less invasive than tradition valve replacement surgery
Jim Cissel: What are the symptoms someone might experience if they had this disease?
Dr. Rizik: The most common symptoms with aortic valve stenosis are symptoms as such as shortness of breath, or short windiness. Some patients might experience light headiness and dizziness. Other patients might have chest discomfort or chest pressure. The patient we saw several weeks ago actually experienced all of those symptoms, and had a degree of fatigue which limited her mobility.
Jim Cissel: Now you say fatigue and shortness of breath, but is it dangerous. Can it be fatal?
Dr. Rizik: Generally, genetic aortic valve stenosis is considered a disease of plateaus, in other words a patient will worsen, symptoms will worsen. They may grow short of breath, light headed and dizzy, and that will persist for some time, and then after a period of time it will worsen, it will go to the next plateau or the next stair step in terms of symptoms. Eventually, a patient can die from the complications from aortic valve stenosis because the heart begins to fail, the strength of the heart begins to diminish, and they could accumulate fluids in their body.
Jim Cissel: So it is not opening fully so they have to work harder to pump, it is not getting sufficient flow, it's wearing out in other ways.
Dr. Rizik: That is exactly right. The heart eventually wears out, the heart eventually dilates, and the efficiency for which the heart pumps blood to the rest of the body begins to fall off.
Jim Cissel: So you have eluded before that TAVRs really only applied to the toughest cases. I mean and yet it has pretty good results in terms of the success ration and how long people live and the kind of life's people live. Do you ever see the procedure being applied to a younger, healthier patient?
Dr. Rizik: Well, I think that is all of our goals. It is to make TAVR so successful and to advance the technology so far that it is being applied to younger, healthier patients, in other words making valve replacements for younger patients less invasive as well.
Jim Cissel : What are the advantages, what are the benefits to the patients?
Dr. Rizik: The benefits to our patients that undergo TAVR are really simple, number one they feel better and number two they live longer. Feeling better and living longer becomes a great motivation for advancing this technology, and remember these are very elderly patients; all of the patients are generally over the age of eighty and many over the age of ninety. Your patient selection is very important because you are talking about extending the life of a very elderly patient, and making them feel better, quality of life. And that is a very important aspect that you have to consider when are considering who the ideal candidate for TAVR might be.
Jim Cissel: So great benefits, let's talk candidly about the risks. What are some of the risks of the procedure?
Dr. Rizik: Any procedure such as TAVR is not without risk. I think from the studies and a lot of the research that has been done, the biggest risk we worry about would be that these patients are at risk for a stroke. We always worry in elderly patients in whom we implant a new device, albeit minimally invasively, we worry about strokes in these patients. These patients are at risk, not only for stroke, but for vascular complications. We can tare or perforate the artery even if you are very careful there is the risk of vascular complications, so we have to proceed with great caution.
Jim Cissel: What about the downsides. Are there any complicated medications you have to be on for the rest of your life, any procedures or limitations that are imposed because of it?
Dr. Rizik: I think most of the downsides of transcatheter valve replacement is really upfront downsides. There aren’t necessarily specialized medications. We use blood thinners in these patients. We are not really certain how much blood thinners contribute to the overall durability of the valve or the procedure. There are no special limitations, in fact we say to these patients we want you to take this for a test drive, to baby yourself, do the things you want to do. This really opens up a lot of possibilities for these patients and there are few restrictions after. Most patients really feel so much more better that it is hard to slow them down.
Jim Cissel: I think that there is also some complications with leakage from the valve post-surgery.
Dr. Rizik: There is no question about that. One of our concerns is once the valve is implanted, is it implanted crisply so that the valve is up against the wall of the blood vessel, which is implanted. If it is not perfectly implanted there can be leakage around the valve. Remember that these patients have fibrous tissue and calcium at the level of the valve where it is implanted. So there may not be a great seal, so there could be a perivalvular leak. Perivalvular leak is one of the things we worry about the most because the more leakage that there may be around the valve where that valve should be sealed to the surrounding tissue, the worst outcomes for these patient. So we look very carefully, we have an echocardiographer at the head of the table, who is giving us real time feedback, so that we can see if there is a good seal between that new valve and the surrounding tissue or not. If there is not a good seal and if there is perivalvular leak, the TAVR procedure will not be as durable, these patients will not perform well over the next several years. However, when there is a very good seal there and there is little if any perivalvular leak, these patients tend to do very well.
Jim Cissel: Now with the traditional sowing, the valve in place, that probably makes for a pretty secure fitting, you don't have the…
Dr. Rizik: Right, there is usually very little perivalvular leak with traditional surgical valve replacement because you are sowing it, you are not just ballooning the valve into place, but you are actually sowing it into place, and therefore there is an ability to control the amount of perivalvular leak by the way you sow that, or anastomose that the surrounding tissue.
Jim Cissel: It is a long way from the growing to your heart, and you are kind of flying in the dark.
Dr. Rizik: It is a long way between the growing and the heart, but you are not really flying in the dark because we use x-ray or fluoroscopy, real time x-rays images or fluoroscopy, to guide us up to the disease the valve. So we can see pretty well. There is a lot of potential complications along the way, not the least of which in an elderly individual, remember most of these patients are over eighty years of age. One of the more common complications we can experience will be vascular complications, going from the thyroid growing area all the way up to the heart. These are eighty year old arteries, they too can be diseased, they can have fibrous tissue and calcium, there can actually be blockages in these arteries. So we are taking this transcatheter valve along the way up from the groin all the way up to the heart to implant it. And there can be vascular complications along the way.
Jim Cissel: And through the echocardiography and the images you are watching, how accurately can you place that replacement valve?
Dr. Rizik: Actually very accurately. When we move the valve up through the artery we reach a point where we will get to the god given or native valve, and then we will place the transcatheter valve through that disease valve. And then using echocardiography or ultrasounds, we can move this, a matter of millimeters, to get it in just the perfect position, so that the valve implants perfectly and so that the valve functions perfectly. So really when you ask how exact the science is it, we have to move it millimeters either direction towards the heart or towards the aorta to approximate the perfect position so that it function perfectly.
Jim Cissel: How long will these valves last, do we know that?
Dr. Rizik: Well, when you talk about how long these valves last, we obviously compare to the mechanical valves, which were developed in the 1970s. They did accelerated valve testing on the valves, on the metal valves that were developed in the 1970s, and demonstrated that these would work for hundreds if not thousands of years. So when you ask the questions how long these valves last, obviously we want try to achieve that golden standard. We don't know how long these TAVR valves will last, we have patients that were planted seven or eight years ago, and those valves seem to be doing well. I think again that it is a work in progress, determining first how long the current valves will last, and then developing new TAVR technologies valves that will give us longevity, that will allow these valves to work for a long time in these people. Only when we can develop minimally invasive valves or valve techniques, which are durable for decades, will this be applied to younger healthier patients.
Jim Cissel: And how do the biovalves or the biological materials, in this case was bovine material was implanted right?
Dr. Rizik: Right the TAVR valve is a bovine pericardial tissue, which is sown onto a metal cage.
Jim Cissel: And how do they hold up to compared to the old mechanical, purely mechanical valves?
Dr. Rizik: We really don't have all of that information just yet. Again, that is a work in progress.
Jim Cissel: We first went into the operating room you couldn't help but be impressed on how many people there were, how many medical, well you had film crew too, but all the medical personal, all the equipment there, and constantly they were always doing something. It wasn't like there were people doing catheter and valve were waiting for you to do the echocardiography, everybody was doing their procedure, and it was like you were some conductor or quarterback relative than a soloist out there. It was a team effort, but that's got to be expensive?
Dr. Rizik: It is expensive, and it is important. The team approaches are very important. First it is very interdisciplinary. There is an anesthesiologist and an echocardiographer, a noninvasive cardiologist, at the head of the table. There is a number of nurses and technicians, x-ray techs, there is an open heart surgeon, and several intervention cardiologist doing the work on the balloon and the TAVR device. There is a number of people, but I think that the important part to this interdisciplinary approach, everyone is working in parallel, not working in sequence. Everybody is actively doing something for the benefit of the patient. I haven't seen a technique that is so depended on interdisciplinary communication such as TAVR.
Can the transcatheter valve come loose in the heart?
Jim Cissel: Is there any chance that that could come loose in there?
Dr. Rizik: Most of the concern about the valve coming loose is when you first implant it. There generally is not a great concern after it is implanted successfully that it is going to move one direction or the other. Once it is implanted it generally doesn’t move.
What is the typical hospital stay and recovery time?
Jim Cissel: Typically…hospital stay… recovery time?
Dr. Rizik: Well I think in her case, had she not needed the hip replacement surgery, we would have sent her home the next day. Traditionally we are seeing about forty-eight hours these patients are generally ready to go home.
Jim Cissel: Let’s talk little bit about cost, it got to be an expensive operation. Ball park figure on what a typical TAVR procedure would cost?
Dr. Rizik: Well the device itself, in the $30000 to $40000 range, if that tells you anything, and so much of the cost associated with heart procedure today is the length of stay in the hospital bed, medication, etc. That is where a lot of the cost comes; the beauty about TAVR is that we abbreviate the hospital stay. So while the device itself might be expensive, by limiting the hospital stay to just a day or two, that is one way we are going to be able to cut cost of treating the sickest patients with aortic stenosis.
Jim Cissel: So are these operations covered by insurance for the most cases?
Dr. Rizik: For the most part, we at our institution have been able to accomplish medical reimbursement for this, but that is still in initiative that is in flux. Who Medicaid is going to cover, or who insurances are going to cover, that is still a work in progress.
Jim Cissel: What about the critics that might argue that you know, that is a lot of money for surgery for people that are pretty old and don't have that many years possibly left?
Dr. Rizik: TAVR or Transcatheter Aortic Valve Replacement has had its share of critics. A decade ago when these procedures were just being developed, and the technology was just being developed, people called proponents of TAVR cowboys, they said you’re crazy. They said it will never work. Some of the critics also said, why are you applying such an expensive technology to vary elderly patients who may not have many years left to live. I got to say, we are applying this technology to what I consider to be a great generation of individuals who lived through world wars and depression. These are individuals who while they are elderly; they are still enjoying their lives. We help to prolong their lives and help to improve the quality of their life. I can't think of a better reason than for trying to promote TAVR and this technology than that alone.
Why is there a slightly higher risk of stroke with TAVR?
Jim Cissel: So you are suggesting that there is a slightly higher risk of stroke for the patients that do this procedure. Why is that, what's that to do?
Dr. Rizik: There is no question that there is a higher risk to stroke. If you compare TAVR to what is now the golden standard, transitional open heart surgery, TAVR patients can have a higher rate of stroke. However, the mortality rate, the number of patients that will die of the results of the disease or as a results of the procedure, that will be lower with the TAVR patients. So there is a tradeoff. Something’s have a higher risk associated with this, such as stroke, other things such as mortality or dying has a lower rate associated with TAVR.
Jim Cissel: So is it because with the open heart surgery you actually cut the old valve and the calcified is out, were in this one you are replacing it and maybe some of that calcium got loose in there and that went someplace else?
Dr. Rizik: There is no question about it. When you place a balloon in place in this disease calcified aortic valve and then you inflate that balloon, there can be debris that goes to a distant sight. We called that embolization. There can be debris that can embolize to a distant sight, such as the brain, and that can lead to a stroke. There is no question that with ballooning the aortic valve and implanting the valve on a balloon, that there can be embolization of debris or debris that moves from that calcified aortic valve to the brain and that can cause a stroke.
Dr. David Rizik utilizes medical illustrations in The Latest Procedure: Transcatheter Aortic Valve Replacement to show anatomy and surgical entry approaches. Those images, along with his explanation for each, are provided here as an additional resource. The caption information is from the television program.
Medical Illustrations: Mike Austin
Dr. David Rizik explains the transcather aortic valve replacement procedure with the assistance of an animated video.
Animated Video courtesy of Edwards Lifesciences
Traditionally, the therapy for aortic valve stenosis has been surgical. It’s still the gold standard. What it requires is for the surgeon, the open heart surgeon, to saw the chest open and spread the ribs and the muscles.
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