HeartBeats Episode 3: Impella/Aortic Balloon Pump

Welcome to HeartBeats. I’m Cathy Murtagh-Schaffer and I am your host for this episode of HeartBeats. This podcast is brought to you by Shipley Cardiothoracic Center - an educational series dedicated to providing our patients and the community with information and education about our Cardiothoracic Surgery program.

Today we have with us Dr. Randall Buss, one of Shipley’s founding surgeons to talk to us about a very special device in heart surgery called an impella. Welcome Dr. Buss and thank you for being with us today.

Perhaps we can start off this discussion with a little bit of history. Can you tell us exactly what is an impella and some of the history behind its evolution?

Well the original pump device that's been used for decades probably since the 1970s is the intra-aortic balloon pump. That name is kind of a misnomer because the intra-aortic balloon pump is actually not a pump, the intra-aortic balloon pump is a catheter that goes on through your artery in your groin and on the end of the pump is a basically a sausage shaped balloon and it inflates and deflates with the heart cycle to take the load off the heart. For example, when the heart is beating the balloon is down so the blood is practically sucked out of the heart into the aorta, the artery of the body and then when the heart is not beating the balloon goes up but it doesn't actually deliver flow. It just beats with the heart cycle to make it to do two things number one take the load off the heart and #2 to increase the circulation through the heart's arteries, the coronary arteries. (host) So in essence it's kind of facilitating the pumping action of the heart. That is correct the intra-aortic balloon pump doesn't pump but it helps the heart to pump it takes the load off the heart but it does have its limitations since it's not really providing blood flow. (host) mhmm, it's not it's not providing that push that goes makes blood flow through the artery. That’s correct.

so how has this impella device come about, what's the history behind all of that?

This device was developed approximately 15 years ago and it has a coaxial screw in the device that is based off the Archimedes screw from Egyptian history 25 hundred years ago, where it's on a micro axial device that then can deliver flow through the catheter up to about five to five and a half liter. Now I will tell you every minute the normal heart pumps about 5 to 5 and a half liter, so, it can deliver full flow for the left side of the heart. It's amazing because the device is not big, it’s about the size of a pencil in diameter but it can give tremendous flow of 5 liters through that device about every minute bases, it's rather an amazing device.

And I'm looking at this device Dr. Buss has in his hands and he's right it's not much bigger than a pencil and it's pretty interesting to think that this little thin cord could actually send that much blood flow through the body. Does it facilitate the other side of the heart and he returned?

The basic device is used for the left side of the heart, there is a second device for the right side but for the left side of the heart when you unload the left side of the heart it makes it easier on the right side of the heart but there are some patients that once we fix the left side of the heart we realized the right side of the heart also needs work and we put in a right sided impella device.

Has the impella gone through randomized clinical trials and what did those trials show?

This all started about 15 years ago, initial approval was about 10 years ago. The initial devices only delivered about 2 1/2 liters and then there's one that got 3 1/2 liters of flow and there's one last couple years at 5 liters of flow. Let's start with what is the device used for? It’s used basically in two places. Number one in the cardiac catheterization laboratory and number two in the heart surgery operating room. The indications are usually one of two. Number one if a cardiologist is doing percutaneous intervention or stent with balloon on a high risk patient lot of times they're worried about the risk of that procedure and they will put in the 2 1/2 or 3 1/2 device to make it easier for the heart during that procedure and that's used quite commonly now these days for the high risk percutaneous interventions now the second group of patients are the patients in shock. Basically they've had a huge heart attack and came into the hospital and they're dying of a heart attack (host)cause their hearts just not pumping and those patients are always initially taken to the cardiac catheterization laboratory, where they look at the coronary arteries and but if the patients in shock they will put one of the 3 ½ devices into the patient. They are limited if they come up through the groin arteries, where they can only put in a 2 1/2-liter device but if the patients in shock they can put a 3 that powers 3.5 devices which gets about 2/3 of blood flow and they could do the catheterization, maybe try to do stents or maybe they give the heart surgeon call and say this guy needs more work than a stent.

when the patient goes to the operating room the impella stays in that's been inserted?

that is correct the device if you can imagine the device goes up through your groin artery circles around the aorta and then it the device actually fits through the aortic valve into your left ventricle which is a main pumping chamber of the heart and when it's inside the left ventricle it sucks the blood out of the left ventricle inside the heart and goes through the micro axial screw and then it's delivered to the aorta, 2 ½, 3 ½ , 5 liters of flow but yes the device actually goes through the aortic valve.

And I'm assuming this device on the outside is connected to a machine of some sort. yeah there's a machine that runs it and if the electronics are unbelievable because now they could be monitored from home or or let's say you need monitoring in a different country, the company can help you monitor the device because it's all electronics now (host) that's amazing that is amazing

Please explain to our listeners why you would use an impella versus an intra-aortic balloon pump? Do they have different purposes?

There's basically two groups of patients that we see in the operating number are the patient who comes in with shock and we have to take the patient to the operating room because they're dying unless we do something. In those patients we recognize that when we do the surgery after the surgery the heart usually won't function really well for a few days and they have to be on high doses of drugs which are detrimental to other parts of the body for example the kidneys, the brain and the lungs, and that patient is in terrible shock, we will bring them to the operating do the bypass surgery and then we will generally put in a five or five and a half liter device, so basically the heart can rest while it recovers and that's the patient who's in shock. The second group of patients which we see much more frequently recently is patients who have chronic heart failure, these are the sort of patients who are at home, they can't walk from one room to the other because they get so short of breath because their hearts not function correctly and they need major surgery, generally they need valve surgery sometimes more than one valve maybe two or three valve surgery. They may also need bypass surgery but the mortality of that surgery maybe 50% and so in the past we've not been able to offer that surgery because, as I said we would lose half the patients and that's just not a reasonable thing to do. But unfortunately the patients are sitting at home and their suffering. I mean they just can't walk they can’t lift and now with this device and we've used the device in about 20 patients and we planned to put the device in at the time of surgery we have a 95% survival with only 5% mortality so that's a dramatic improvement and certainly the patients will take a 5% risk as they're just suffering at home. We will put the device in and we’ll do the heart surgery, now this is a temporary device so we’ll use them for five or six days and then remove the device. The permanent VAD devices or something completely separate and are not like this but these are temporary devices that we can use.

Which brings up an interesting question how is that removed?

Well it depends where it's put in if it's put into the groin it's just remove from the groin it just pull it out and add pressure or the cardiologist will take it out at the end of his procedure in elective procedure in the Cath lab. Generally we put them in either through the artery going to the arm, that's one way we can do that and what we can do is just cut down, there's a Dacron graft sewn to that artery in the arm and we’ll pull out the device and staple off the graft. But more and more we've been directly putting them in to the aorta through a Dacron graft and that's what we generally do in the operating room. (host) so once you've opened up the chest. that's correctly. So what we do is we at the end of the first operation the device is brought out just above the chest incision on the side of the neck and that makes it equally easy for us to come back let's say five days later we take it back to the operating room put them back to sleep but just make a small incision on the neck we extract the device and staple off the Dacron graft so we don't even open their chest and so the patients think it’s just rather amazing. The one thing I find most amazing, and I've been doing heart surgery for over 30 years and so we see we've seen the patient for years we've taken to the operating room it's just a huge operation and we came through the surgery but they're on very high doses epinephrine and norepinephrine and they're just suffering there sitting on the ventilator now when we do the zone planned procedures in patients it's frequently the next morning they're up sitting eating breakfast as you walk to see him at 7:00 AM they've got this device coming out the side of the deck flowing at 5 liters a minute but they just sit there talking to you, they feel great feel fine. They’re generally on no drugs or very few drugs and so the important thing is all the other organs are getting normal blood flow, the kidneys, the brain, the lungs, the liver and they're not suffering at all. In the past a lot of times the heart got better after three or four days but the patients other organs suffered so much that they died of multisystem organ failure and now we're protecting all the other organs with the device and we just wait until the hearts fully recovered to remove the devise.

What are risks inherent in the use of an Impella?

The risk of the Impella, we have not seen problems ourselves. Now if you go in through the artery in the groin and the patient already has blockages in the arteries of the groin, that can be a problem with the blood flow to the leg for example that's one thing. We have not seen trouble with placing it directly into the aorta we have not seen for example, have not seen it puncture the heart, we have not seen that, now what we have seen is sometimes the device will move a little bit and we have to come in using echocardiogram which is ultrasound evaluation of the heart that can see device, and we may have to adjust the location of device but we've not seen complications of the device itself

Any issues with clotting around the device?

No, we put them on a low dose blood thinner, Heparin, generally later that day we've not seen the device clot in the patients we have done and there's some patients who at other locations have had the device for several weeks and they've not had major problems either it's a rather remarkable device. (host) I know that one of the big concerns with some of the earlier L VADs was the problem of clotting and so I was curious about this. That's not been a problem that we've seen I think one of my partners had one that stopped stop functioning a couple days later and he just took the patient back the operating room and took that one out and put another one back in and the patient did just fine and had that one taken out a few days later. (host)amazing just amazing

I think that it's very impressive the data that you just presented as far as your surgical outcomes are concerned do you have a feel for what nationally the data looks like?

There's two groups of patients, both in the Cath Lab and in the operating room. The patients that you plan to put the device in, generally do very well in both the operating room and Cath Lab. The patients who are in shock when they come in with a bad heart attack and they're put in the Cath Lab, their mortality is much higher because they're dying of heart attack or in the patients who at the end of heart surgery are doing very poorly, and then we try to put the devise in, we have not seen good results for that obviously. I think mortality is probably at about 50% but the ones we plan to put it in advance involve well at least the vast majority of them extremely well

So there's this criteria that you use for evaluating patients who come in who you know need heart surgery and you have to make a decision about whether or not you're going to put this device in and that includes patients who have either massive heart attack and the heart isn't pumping well or patients who have been in persistent what we call heart failure that got water on their lungs, they have swelling in their ankles and have had a chronic problem with this. Am I saying this correctly? (Dr.Buss) I agree I agree completely Great, do you feel that this device has any futuristic potentials?

Well they upgrade the device every few years, the flows have gone initially from you know 2 1/2 to that 5 ½ liters and as I was saying now in just the last few years they've got one for the right side of the heart which comes up through your vein in your leg instead of the artery in your leg and that's been quite effective but the interesting thing is as technology improves one wonders that they're getting smaller and smaller and it's amazing what they've already done but there's always amazing in what they're going to do so one would hope that devices would get smaller and smaller and be used in a less invasive way and they're already very good but we're always hoping for something that's better.

any application for this device in our covid related heart issues?

Now usually the covid related issues or lung issues, although, clotting has been a problem in some patients. We have not used this device if we've had patients with COVID pneumonia, particularly younger patients who just cannot oxionate, literally their lungs don't work so they're not absorbing oxygen into the blood, what we will generally put them on is what's called ECMO which is basically a heart lung machine and that way we can deliver the oxygen to them. We do that very rarely because if they need that they’re profoundly ill and they're literally dying and we use them for the very young patients. I did one just a few weeks ago with hopes we can make him pull through but this device would not make the lungs work better just makes the heart work better.

Lastly, I think our listeners would like to hear if Shipley has any outcome data to share with our listeners regarding the use of the impella in our cardiac surgery program? How does that compare to other sites?

The times I've used this device it's just a leap forward because I've been doing hardship over 30 years and I've done patients just like this over the years and had patients who some we struggle to get them through or they lost their kidneys or on dialysis or with just barely made it through and this device gives you a safety it gives you a large margin safety that it's really kind of a leap forward and it's just a pleasure to actually use the device (host) I was going to say it must be such a relief. It's a relief and see the patient the next morning talking to you instead of laying there on the ventilator or maybe even on dialysis for goodness sake it's just it's just a pleasure to use. (host) It’s big amount of satisfaction that I can imagine

Dr. Randall Buss, thank you so much for being willing to share your knowledge and experience with our listeners. I know I learned a lot today.

Join us again for an upcoming podcast when Dr. Buss will be speaking to us about coronary artery bypass surgery, the most common type of heart surgery.

Until then, I’m Cathy Murtagh Schaffer and this has been HeartBeats, Shipley Cardiothoracic Center’s podcast dedicated to bringing research, innovation and education to our patients and the community.