PAH Today: Beyond the Basics - phaware® interview 351

Nov 25, 2020

SPECIAL EDITION: Beyond the Basics

The PAH Initiative and United Therapeutics are excited to bring you the PAH Today National Broadcast Series. This series of virtual events is intended for adult patients with pulmonary arterial hypertension (PAH) and their caregivers.

Advancements in the care and treatment of PAH are improving the lives of those impacted by this life-threatening disease. The National Broadcast Series will include insights and perspectives on today’s approaches to managing PAH from nationally recognized PAH healthcare providers. Join patients and caregivers across the nation to hear current considerations in the care of PAH.

This is the first of 4 PAH Today broadcasts to learn more about your symptoms and how your healthcare provider can use them to monitor your PAH. Presented by Dr. Lana Melendres-Groves the Director of the Pulmonary Hypertension Program at the University of New Mexico and Dr. George Ruiz Chief of Cardiology at MedStar Union Memorial Hospital. Learn more at: www.pahinitiative.com 

Lana Melendres-Groves, MD:
Good afternoon, and welcome to the PAH Today National Broadcast: Beyond the Basics. My name is Lana Melendres-Groves, and I work at the University of New Mexico as an associate professor and medical director for the pulmonary hypertension program. On behalf of United Therapeutics, myself, and everyone joining us today, I want to welcome you and thank you for being here. Whether you're on your own PAH journey or here to support someone you love, we appreciate you being here and the time that you're taking out of your day to join us. As our disclaimer, this presentation is sponsored by and made on behalf of the United Therapeutics. Healthcare professional speakers such as myself are compensated by UT. Not all drugs are appropriate for all patients. Speak with your healthcare professional to determine which treatment plan is right for you. Patient experiences relayed during this program may not represent the experience of a typical patient.

Well, I'm excited to get started, and first I'd just like to go through a bit of an overview for the presentation today. We have three separate areas. The first is going to be about PAH and the disease state overview. This will talk about how the changes in your heart and lungs cause the symptoms that people experience from PAH. The second section is going to delve just a little bit deeper into the science behind your symptoms. Don't get scared. I promise it's not going to be too bad. The third is going to be keeping track of your symptoms and why that becomes so important for you and for your healthcare providers information.

All right, so let's get into it. Here's the overview for PAH. Now, when I talk to my patients, I find that it's really important for them to really understand what we're doing together and why they feel the way they feel. So to start with, we talk about how the heart and the lungs, they work as a team. They're a pretty complex team, but nonetheless, they're equally as important. I think that what I'd like to do today is start with the heart. And we'll talk about how that may be affected by PAH, and how that may lead to the symptoms that each person may feel. So first, the heart has four chambers. I'm sure many of you already know that. Sometimes we talk about it as the right side or the left side, sometimes we talk about it as the upper chambers which are smaller, or the lower chambers which are larger. I think that no matter how you talk about it, you just have to understand what the job of each side of the heart is.

In this illustration, you can see that a portion of the heart, one of the larger chambers, a ventricle, is on the left side. It's depicted in red, because typically we indicate oxygen rich, or blood that's filled with oxygen as being red. On the left side of the heart, you have the left atrium, which is the smaller chamber that receives blood from the lungs. This blood entering the left atrium is going to then pump that blood through to the left ventricle. The left ventricle will then pump that blood out to the body to distribute oxygen to the tissues, the organs. It keeps us going, keeps us alive. Most of the time we hear about heart disease or heart attacks, and really what people are talking about is a disease of the left side of the heart or the left ventricle. This isn't what the problem is in pulmonary arterial hypertension. It's actually the right side of the heart. So why don't we jump over to the right side of the heart and see what's going on there?

In the right ventricle, depicted in this illustration as blue because it's low in oxygen. It's called oxygen poor blood. The right ventricle is what becomes affected in pulmonary arterial hypertension, and just starts to not work the way we need it to. Overall, the body is dependent on oxygen to survive. When the blood is distributed to the rest of the body and gives that oxygen off to the tissues and organs, it then needs to return to the heart to be pumped into the lungs. That's where the right side of the heart comes into play. The blood returns to the right atrium, which is the smaller chamber, and that right atrium then squeezes and pushes the blood into the right ventricle. The right ventricle then is able to contract or squeeze and push the blood out into the blood vessels of the lungs, where oxygen is waiting, and those red blood cells are able to absorb the oxygen and now become oxygen rich and head over to the left side of the heart, where the entire process goes on again and again.

In patients with PAH, things change a little bit. What we know is that the blood vessels of the lungs become affected. They start to narrow, they start to thicken. So now those tubes or vessels that blood easily flowed through to pick up oxygen are very small, narrow, and unable to do that job as well. What happens is that the right ventricle, being a muscle, says, "I'm just going to increase the pressure. I'm going to send that blood through those smaller blood vessels, because that's what my body needs." Unfortunately, what happens is that over time, that right ventricle having to work overtime day in and day out, I always describe it like running a marathon, which I could never do, but at least I could have a time point that I could rest. The right ventricle is in a situation that it continues to run this marathon without an end in sight, and over time starts to become enlarged and not work as well.

This is where patients begin to have symptoms. They start to feel that shortness of breath and they start to feel the other fatiguing symptoms that often take them to a physician in the first place. But before we get there, I think sometimes trying to talk about the teamwork of the heart and lung may better be explained by a good friend of mine, Dr. George Ruiz. He has a really interesting take on something that we actually see day in and day out, and is applicable to our heart and lungs. So at this point, I would love to turn it over to Dr. Ruiz.

George Ruiz, MD:
Hello, my name is George Ruiz. I'm the chief of cardiology at MedStar Union Memorial Good Samaritan and Harbor Hospitals. And more importantly, I'm a heart failure physician that specializes in the care of patients with pulmonary arterial hypertension. Today, we're going to talk about something really important to not just cardiologists, but to the patients they treat. Flow.

Blood flow is a very important component in being alive. It is the currency of life. You need blood flow to get around your house. You need blood flow to walk your daughter down the aisle. You need blood flow to do those things that make life meaningful. As long as we're living, there is blood flow. The analogy of a highway really can help us understand. The heart pumps blood to the lungs through a series of arteries, which we can think of as highways. These highways in the lung have a large number of lanes. As a result, the blood flow between the right side of the heart and the lungs generally flows under low resistance.

The analogy here is imagine that you were going to work in the morning during rush hour and the highway you took had not four lanes, not five, but 11, 12, 15 lanes. That traffic would flow a lot easier. There would be very little resistance to flow. That's what the normal lung blood vessels look like. They're generally low resistance blood vessels, and there's a lot of flow. The reason why that's important is because we need that flow to the lungs, because in the lungs is where you take in oxygen, and where that oxygen gets connected to the blood, and then ultimately delivered to all your tissues. As a result of any one of a number of insults, the blood vessels shift, and they remodel. This is a medical term, remodeling.

If we go back to our highway analogy, what remodeling looks like is imagine that there's an accident on the side of that same highway. What happens when you have an accident is that you get lanes closed. The police show up, they start closing lanes. So now imagine that same commute that you have in the morning, and instead of 15 lanes because of accidents, now you have 10, or eight, or five, or two. As you close more lanes on the highway, the resistance to flow increases. As you increase the resistance to flow, you create a backup behind where the accident is. This is stuff that intuitively we've all been on a highway where there was an accident, and what do you do? You sit there. The flow gets reduced. Sometimes the flow gets reduced to a very slow trickle. Sometimes the flow gets reduced to a standstill. As a result of this, there is less flow. And as a result of there being less flow, to patients that means there's less go. Flow equals go. You need the flow to do the things that you want.

So as the flow reduces, the patients get less. They do less, they walk around less. They go to the supermarket less. Things that they used to be able to do become very challenging, because they have limited flow. So what we do is we try to assess what the resistance is in the blood vessels in the lung. We attempt to assess how much flow there is. A lot of that, we can get initial glimpses of it when we do the transthoracic echocardiogram, the pictures of the heart. We get an idea for the backup of the traffic, the right ventricle, which is the main pump to the lungs can sometimes become very dilated and distended, and that can often be a sign that the flow is being limited by resistance. Then ultimately, we send patients for a right heart catheterization, where we can actually measure the flow. By looking at the pressures in the lung and the flow, we can calculate the resistance.

Now these numbers are incredibly important to me as a heart failure specialist, because they helped me understand the severity of the disease, they help me understand how limited your circulation is, how limited is your flow? It also is important to you, because it helps guide how I choose how aggressive to be with regards to medications, whether we make changes. But the most important reason why it matters is because it tells us a story about you. It tells us about where you are. It tells us about where you are with your disease. It gives us an indication about how aggressive we have to be. I hope that helps you understand a little bit better how all the plumbing is connected inside of you and how that's related to the way that you feel. Also to how I think about your disease and how I use this to help guide what we do for you.

Lana Melendres-Groves, MD:
Well, thanks, George. I think we'll all agree that sometimes traffic jams are definitely a mess, but I think it really is a good depiction of what potentially is going on in our heart and lungs, and why all of us can be very frustrated at times in trying to deal with it. Speaking of some of those difficulties and frustrations, that often comes to talking about symptoms. For me, this is where I tend to have conversations in great detail with my patients, because for them, they may experience things such as shortness of breath or limitations in what they can do. They may describe hard or fast or irregular heartbeats. They may find that they have swelling in their abdomen or swelling in their ankles. For them, that is most important. For me, that is something that I really need to take into consideration. It becomes important as we move forward in not just diagnosing somebody, but in how we follow them further into their treatment plan.

Many of these symptoms are simply a result of the right side of the heart not being able to keep up with the job that's being asked to do. Unfortunately, because PAH is a progressive disease, we expect things to worsen over time. So, many things that we would take for granted, such as doing our laundry or going shopping, are things that we can no longer do with ease. These are opportunities for us to consider what it is we may need. It helps our providers to make decisions and recommendations on your behalf. Overall, it's important to keep track of these symptoms. Because whether they're improving or worsening, that may affect how we recommend treating you. On the other hand, maybe your symptoms are staying the same. That doesn't necessarily mean that there aren't opportunities to improve the way you feel. So it is extremely important to try to monitor those symptoms and activities that you're able to do.

All right, we made it through section one. So that brings us into section two, a little bit deeper dive into the science behind your symptoms. Now I know that many of you, science may not have been your favorite subject in school. So we're going to do our best to try and make this something that is applicable to you and why certain treatments may be the right options for you, or why others may be more appropriate. All right, let's get into it. So first we need to talk about what normal is, because only when we know what normal is, can we then talk about the abnormal. In this situation with PAH and with everybody, we have three substances that the body produces. Nitric oxide, prostacyclin, and endothelium. These are all produced in normal, healthy lungs, and when working properly are produced in just the right amount. These substances keep everything moving and flowing easily through the blood vessels.

So what do they actually do? Well, let's talk a little bit about that. For nitric oxide, this is a substance that is produced in the inner lining of the blood vessels of the lungs, and it helps to keep the blood vessels open or dilated. Prostacyclin is another substance that's produced in the blood vessels of the lungs, and once again helps to keep those blood vessels open so that blood can move freely and easily through the blood vessel. Prostacyclin also has a few other jobs. It helps to prevent blood clotting, it also will prevent thickening of the blood vessels of the lungs.

So that brings us to endothelium. This is sort of the counterpart to these. I always describe these substances as sort of a teeter-totter. It's not a very fun teeter-totter if they're working normally, because nitric oxide and prostacyclin would sit on one side, and the endothelium would sit on the other, and they weigh the exact same and nobody gets to go up or down. That's okay when we're talking about the body. We like things to be just in balance. So what actually happens then if that isn't the case? Well, that brings us to PAH. This the time that we see these substances becoming out of balance. We see that there's a decrease in the production of nitric oxide and prostacyclin, so there's just not enough around. We're not able to hold those blood vessels open, there may be thickening of the blood vessels and endothelium, on the other side, there's too much of it. So now we start to see thickening of the blood vessels, narrowing of those blood vessels, and now all of a sudden our teeter-totter is a really large adult who has two little children sitting on the other side, and now we've tottered over to the side of constriction and narrowing of those blood vessels that puts that extra strain on the right side of the heart.

These substances are also opportunities for us, because researchers over the past 25 years have worked so hard to try and improve the lives of our PAH patients. We now know that although they don't work appropriately in our PAH patients, these are also the areas that we're able to treat patients, and with medications potentially affect the amount of each of those substances. Now today, we're not planning on talking about those medications. That will actually be in our third installment of PAH Today, our National Broadcast Series. So I'm hopeful that you're able to join us again to discuss the medications at that time.

Instead, I think we should get into tracking of symptoms, and why it's so important. Before we get to it, I know, my patients, they're frustrated. I'm asking them to come in. They have appointments. They have tests. Now here I am about to ask you to do one more thing when you already don't necessarily feel at your best. But I think it's important to understand why tracking these symptoms can be so helpful. Not just for you, but also for your healthcare provider. When we talk about symptoms, your providers is thinking about it in terms of your functional class or what you can do. So in order to understand my patient, I need to know what their daily life is like. Do they get tired when they're walking to the mailbox, or maybe after we've started therapy those things have improved.

This can all be related back to a functional class. Many of you may have already discussed with your providers and know exactly what your functional class is. Others of you maybe haven't had that opportunity yet. But in order to understand what it means to be classified as a functional class 1 or 3, I'd like to go into the 4 groups. For our class 1, these are individuals who realistically maybe aren't effective at all. They have PAH, but they're able to go on bike rides or long walks. They're able to do all their activities and not feel as though they become breathless.

Our patients who are in our functional class 2, they tend to need to pause during their activities that are a little bit more strenuous, such as climbing stairs or shopping. By the time someone is in class 3, what we find is that they're really having to stop frequently. They may actually have stopped doing some of the things that they normally would have done because of their breathlessness or symptoms that they develop. In class 4, our patients are feeling short of breath or having problems even while they're at rest.

By knowing what functional class you are, it can help in terms of long-term prognosis, how you will do, and what you might need to discuss with your healthcare provider. One way that you might track your symptoms is with a form that the PAH Initiative has created. This allows you to keep track of the date and what symptom you may be feeling. I have to be honest, sometimes I can barely remember from day to day. So to be asked what I could do three months ago, that's so far away from what I'm doing right now I'm not sure I'd remember it. But if I had a quick reference, I could think, "Wow, I could do a lot more back then," or, "Look how far I've come." So I think being able to keep track of this for you, it really helps your trajectory of how you're doing in terms of your PAH.

Well, thank you all for being here and joining us today. I would love it if you would join us next time, and we're going to be talking about how decisions today can shape the future. You can register today or any day at www.pahtoday.net. And please consider joining the PAH initiative at pahinitiative.com, where you can stay informed, stay motivated, and stay focused on your future. Thanks for joining us.

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