Dr. Harold Dauerman, interventional cardiologist and director of cardiovascular services at the UVM Medical Center, tells us about two new and different approaches to cardiology patients – MitraClip and TAVR – that have been saving lives and the continued research we continue to do surrounding these techniques.
Listen to the radio interview below, or read the transcript that follows.
UVM Medical Center: It wasn’t too long ago that the only option to fix major problems with your heart was major surgery. But, more and more, doctors are able to do things like repairing and replacing valves, closing holes in your heart, and preventing the formation of clots using catheters, which are thin flexible tubes that are snaked up into your heart through blood vessels. One of the most significant benefits of this is the ability to treat people who can’t have major surgery for medical reasons. So, I’m not overstating it to say, with some of these procedures, we’re saving lives.
UVM Medical Center has been involved in clinical trials to test some of these devices. We’re going to learn a lot more about this fascinating field of medicine and take a peek at what the future will bring from Dr. Harry Dauerman, an interventional cardiologist and director of cardiovascular services at the UVM Medical Center. He’s also a professor of medicine and surgery at the Larner College of Medicine. He’s been heavily involved in the clinical trials, and recently brought a procedure to our region that repairs leaking valves using a device that looks like a clothes pin and I’m not kidding. Welcome to the program.
Harry Dauerman: Thank you.
UVM Medical Center: You have an interesting job, I would say, in the least. What would you add to that brief overview?
Harry Dauerman: Yeah, I think that this has been an exciting time for the development of technologies to be less invasive and to broaden the population of patients that we can treat with serious heart disease. There’s been a whole other side going on outside of my expertise, which is developing better medical therapies to prevent coronary heart disease. My end is to really focus on those patients who have, for whatever reason, developed problems with their coronary arteries or their valves, and how can we effectively offer these patients a less invasive option that’s safe and effective. The technology has advanced considerably over the last decade, so that we have options that we never had before.
UVM Medical Center: Was there one single breakthrough that made this possible? How do you get these things small enough to fit in a tube that size?
Harry Dauerman: There’s no one moment of breakthrough discovery. This started in 2003 with the first human implant of a percutaneous aortic valve, in France. It was in a patient with no options for surgery, who was going to die from a blocked aortic valve. The caliber of the catheters used for that procedure are twice the size of the current caliber of catheters we use, so a much larger incision in the femoral artery. Still, a fairly miraculous procedure that it worked, but without the iterative developments over the last 14 years, we couldn’t treat little old ladies with much smaller arteries, because the caliber of the catheters were too large for them.
Now, with the miniaturized catheters and valves, we can routinely treat people across a very broad spectrum with percutaneous techniques that involve a three to four millimeter incision in the femoral area to, as you said, snake a catheter up that has a valve on it, and put it in the aortic valve.
UVM Medical Center: And it’s able to expand to a size that fits the opening to replace the old valve and pushes the old valve out of the way. So how is it able to expand to do that?
Harry Dauerman: Aortic stenosis is a blockage of the aortic valve, one of the valves of your heart. It’s basically like a clogged kitchen drain. So we’re able to use two different valves through a pencil-like incision — that’s the diameter of the incision in the femoral artery — to go up using a camera and cross the clogged kitchen drain. These two valves are both like very large stents. They’re made of metal and they have two different ways they expand. One expands like a Slinky, and we just remove a catheter from the outside of the Slinky and it will expand on its own inside the valve and push the old valve to the side.
The other one we expand exactly the way we expand a stent in your heart arteries. There’s a balloon inside it. We inflate the balloon, the stented valve opens and then the mechanics of the valve are so that it doesn’t recoil. So, it will stay locked in whatever position the balloon leaves it in. Then we’re able to withdraw the balloon, the wire, the catheter from the groin, and leave nothing behind but the valve.
UVM Medical Center: So with that valve insertion, when you first started this trial, the population was folks who could die, or were really at high risk for complications of open heart surgery. So are you doing people at lesser risk now?
Harry Dauerman: Where the TAVR program is now compared to 2011, is light years different. For example, just as you said, when we started the program, the idea was to treat people who were at extreme risk for open heart surgery, or not surgical candidates. We know those patients had a 50% chance of dying within a year without therapy, similar to lung cancer. We then offered them the TAVR therapy and we were able to cut their mortality rates in half. That led to approval of the first generation devices, that have since miniaturized and become safer and with that, we’ve been doing subsequent trials in patients who were at high risk for surgery, but still surgical candidates.
Then intermediate risk for surgery, but still surgical candidates, and in those two trials we’ve shown that the TAVR approach is at least as good if not better in terms of saving lives, compared to surgery. For our routine here, is if you’re not low risk for open heart surgery on your aortic valve, you will get TAVR as the first choice. Because the catheters have shrunk in size and diameter, we can offer it to almost every patient who fits the clinical risk profile, and clinically needs it.
A New Clinical Trial Happening at UVM Medical Center
Harry Dauerman: We’re currently doing a trial in two areas: one of them is an area where surgery is definitely the clinically indicated approach, and if you’re low risk for open heart surgery for an aortic valve, we don’t know whether you’re better off getting surgery or TAVR. So we’re currently randomizing patients just like we did back in 2012, but this time they’re low risk patients, they’re patients who are late 60s, early 70s, with limited other medical problems, who happen to have a blocked aortic valve. We’re doing a coin flip and we’re going to follow these patients for two years, and we’ll have an answer if TAVR is an equivalent option, or if it’s not compared to surgery. Until that time, if the patient isn’t wanting to be in a clinical trial and they are low risk for surgery, I recommend open heart surgery.
There’s another area of trial that’s really fascinating, which is, there’s a growing epidemic of congestive heart failure out there. Patients with difficulty breathing due to a variety of problems with the heart muscle, but one of the things that can exacerbate heart failure, is having a valve that’s blocked, but not blocked severely, just on the way to getting blocked. And so we’re doing a trial now, comparing heart failure with medications, to doing TAVR on patients who have moderate blockages of the aortic valve, to see whether fixing these medium blockages prevents the patients coming in with heart failure and needing as many medications.
So the potential to expand the utilization of TAVR over the next five years is very real, and it depends on the outcomes of these trials.
UVM Medical Center: One thing we didn’t mention is the difference in recovery time, which I think for most people would be pretty obvious, but describe just how different it is.
Harry Dauerman: This is a very different conversation today than it was when we started this in 2012. In 2012, if you were getting TAVR, you were in the hospital five to six days, you were going to the surgical intensive care unit. Now, our rule is two midnights, we treat you like a coronary stent patient. You’ll come in, we don’t use general anesthesia anymore, and you will stay two nights in the hospital, and then go home. The surgical aortic valve replacement stay is between five and seven days.
The other difference is, after open heart surgery, there’s a period of four to six weeks of full recovery, before you can return to full exertion. For our patients we recommend a period of say, five to seven days before return to full exertion. It’s a very much quicker recovery without the need for by-pass machine, general anesthesia or a large sternal incision.
I think surgical techniques have improved, there are smaller surgical incisions that can aid the speed of recovery, but there’s no comparing to the rapidity of recovery after the fully percutaneous approach.
UVM Medical Center: You’re listening to Dr. Harry Dauerman, he’s an interventional cardiologist and director of cardiovascular services at the UVM Medical Center, also a professor of surgery and cardiology at the Larner College of Medicine. We’re talking to him today about the expansion of the use of catheters and interventional cardiology to fix a variety of heart problems and real breakthroughs and technologies to do that.
New Development: MitraClip for “Leaking Hearts”
UVM Medical Center: I want to move now to something called the mitral clip, which I mentioned at the beginning, which is a way to repair, not a valve that’s completely not functioning, but leaking.
Harry Dauerman: That’s right, so this has been approved for about four years now. It’s the use of a clothes pin to go up through a one centimeter incision in the groin area to reach this leaky valve. What you have to imagine is that you have a door that’s supposed to shut, but instead the door is swinging wide open. That’s what happening with people who have a leaky mitral valve. This wide open swinging of the door can flood the lungs with fluid when someone is exerting themselves and give them congestive heart failure.
One treatment option if the door is broken, is to do open heart surgery. And that’s certainly the proven option, and for sure the best way to fix the heart valve with the least amount of leakiness, is to do open heart surgery, but this is similar to 2011, when we knew that there was a large population of patients out there who really weren’t good candidates for open heart surgery, due to frailty and age. And so the FDA has approved in patients who are at high to extreme risk for open heart surgery and have a leaky valve due to a broken door, this idea of MitraClip, or putting this clothes pin up on the mitral valve.
The good part about this is that it works; that we are able to decrease the leakiness of the valve, though there are a couple of caveats that go along with both TAVR and MitraClip. It is still an invasive procedure, and there definitely is risk, so we need to always weigh the idea of, is medical therapy the best option versus an invasive approach for all our procedures? And the patient needs to be aware there is still going to be a risk of bleeding complications, a risk of stroke, even a risk of death for many invasive procedures we do.
The other risk with MitraClip is that it doesn’t completely cure the leakiness of the mitral valve to the extent of surgery. Surgery’s definitely better, so if you have a severely broken door, it’ll take you to a mildly broken door.
Now for most of these patients, that will significantly improve their symptoms and keep them from coming in and out of the hospital with shortness of breath and heart failure, so it’s been remarkably successful. We’ve been doing it here since January of 2017, and we’ve seen very clear benefit in this high risk patient group. This procedure is done with general anesthesia, and I work with my colleague Dr. Johannes Steiner who’s one of our heart failure specialists, to get the exact right images so we can do the clipping well, and again, the same rule applies, these patients are in the hospital usually two midnights, two nights and then they are home, and they are allowed to fully ambulate very rapidly after that.
So the recovery is very rapid, and that’s certainly different than an open heart procedure, which is important in this elderly patient population.
Looking Toward the Future of Heart Health Treatments and Procedures
UVM Medical Center: Looking ahead, what do you see coming down the pike, and what are people doing, including yourself, to help develop some of these?
Harry Dauerman: I think that the biggest thing that’s coming down the pike is figuring out when to use these devices. We’re very actively involved, for example, in the clinical trials in TAVR, of the next generation devices in patients that we’ve never used in before. Like the patients with moderate aortic stenosis. With that, if we can find the selected patient populations beyond the ones we’re using now, for these devices, I think we’ll be able to improve the need for hospitalization for heart failure, which is a major issue in our community.
The second thing is the next generation devices, there are 25 companies generating new devices to clip the mitral valve, and there are rapid progressions occurring in the TAVR world, of both new devices, but also even shrinking them further and further, so that the recoveries are quicker. One of the dreaded complications we have with all of our invasive procedures, but especially TAVR, is a 2% to 3% risk of stroke that can occur. Now with open heart surgery it’s exactly the same risk, but we’re hopeful we can find new technologies that can capture debris that’s released during this procedure, and try and take that stroke risk down to the same risk that we have when we stent your heart arteries, which is around three in a thousand.
So there are definitely areas that we need to improve upon, we’ve come a long way in just five years, but I think that we here at the Medical Center are going to continue to look for new indications, new technologies as part of clinical trials, so that we can figure out what is the cutting edge of the field.
UVM Medical Center: It’s just amazing, and as all this progresses we’ll certainly check back with you, but for now I want to thank my guest, Dr. Harry Dauerman, interventional cardiologist at the UVM Medical Center, also director of cardiovascular services, and a professor of surgery and cardiology at the Larner College of Medicine.
Thanks very much for joining us.
Harry Dauerman: Thanks for having me.
UVM Medical Center: For more information on cardiology care at the UVM Medical Center, you can visit our website and just search on cardiology in the box on the top right, or call (802) 847-0000.