I’m Aware That I’m Rare: Victor Test, MD (Part 1 of 2)
Victor J. Test, MD is a professor of medicine at Duke University School of Medicine. He treats patients with pulmonary vascular diseases including high blood pressure of the lungs (pulmonary hypertension) and unresolved blood clots in the lungs (pulmonary embolism). His research specifically focuses on chronic thromboembolic pulmonary hypertension. In this episode, Dr. Test discusses the importance of a thorough diagnostic evaluation and the types of tests that are done to evaluate people with suspected pulmonary hypertension.
I’m Victor Test. I am the director of The Pulmonary Vascular Disease Center at Duke University. I have an interest in unexplained shortness of breath, Chronic thromboembolic pulmonary hypertension (CTEPH), pulmonary embolism, and pulmonary vascular diseases of all sorts.
Today I’d like to talk with you about the importance of a thorough diagnostic evaluation and the types of tests that we do to evaluate people with suspected pulmonary hypertension.
One of the things that’s changed in the world of pulmonary hypertension since I began to develop an interest and expertise in it is the way the approach has been in the general public for pulmonary arterial hypertension or really any form of pulmonary hypertension.
When I first started in this disease process management and managing patients with pulmonary hypertension, I was a resident and at that time, there was only one approved therapy for PAH and that was an IV agent known as prostacyclin. But that was not widely available, so when we would see patients outside of a pulmonary hypertension center who were diagnosed with pulmonary hypertension, we would go to great lengths to try to figure out why they had the pulmonary hypertension because what we were able to treat at that time was the underlying disease process.
For example, if a patient had interstitial lung disease, we would try to treat the interstitial lung disease. If they had thromboembolism, we would treat the thromboembolism. If they had a COPD or sleep apnea or a left heart failure or lupus, we would treat the underlying process. As such, we would get a very thorough diagnostic evaluation once the diagnosis of pulmonary hypertension was entertained.
One of the things that’s changed since I began to take of pulmonary hypertension patients is an explosion of other kinds of therapies. Really for the last 15 years or so, we’ve seen a shift from a problem where doctors would not look for pulmonary hypertension because they didn’t feel there was a way to treat it to a period where we have a delay in diagnosis still, but one of the things that we see now is that patients will be given a diagnosis of pulmonary hypertension but really have no evaluation for that disease.
There is a general increase in awareness for the diagnosis of pulmonary hypertension because of the increased number of agents and drugs that we can use to treat pulmonary hypertension. But I think where the problem comes is once the diagnosis of pulmonary hypertension is entertained, the evaluation of the patient ofttimes is not as thorough as it used to be.
There’s a general misconception among patients and healthcare providers that pulmonary hypertension is a diagnosis when in fact it’s not. It’s a syndrome, which means that it’s caused by multiple different kinds of diagnoses. In general, we divide them into five big groups. There’s [Group 1] pulmonary arterial hypertension, which is what we treat with the various specific medicines that we referred to earlier. Group 2, which is pulmonary hypertension due to left heart failure or cardiac dysfunction and that’s actually the most common thing we see in pulmonary hypertension clinic. There’s Group 3, which is intrinsic lung diseases so patients with pulmonary fibrosis, COPD, obstructive sleep apnea or if you live in the mountains, altitude associated disease. That’s treated very differently than Group 1 and Group 2. Then the fourth group [Group 4], which is in many ways is one of our favorites because it’s potentially curable, is pulmonary hypertension due to old blood clots. Then there’s the fifth group [Group 5], which is a group of diseases that causes it through a variety of different mechanisms or what we call multifactorial causes, multiple causes. We treat each of those different groups differently.
There’s been a general misconception that once you’re given a diagnosis of pulmonary hypertension, it’s all the same thing. For us, as pulmonary hypertension specialists, nothing could be further from the truth. That’s why the evaluation of patients with pulmonary hypertension is one, very extensive, but it’s also very, very important so that we can find the right treatment for a given patient.
In general, when we talk about the evaluation of pulmonary hypertension, there are a basic set of tests, which we use to evaluate heart and lung disease and/or shortness of breath, which are common to most every disease. For many patients, that would start with an EKG or an electrocardiogram where we look at the electrical waves of the heart. The EKG in pulmonary hypertension is not a very sensitive test, which means it will miss pulmonary hypertension when it’s present sometimes and it’s not very specific either. If it has the abnormalities consistent with pulmonary hypertension, it doesn’t tell you the type of pulmonary hypertension.
Another really common test is a chest x-ray. Like the EKG, it’s used to help us look for other things. For example, it can show some specific findings that we would see in pulmonary hypertension: enlargement of the heart, enlargement of the pulmonary arteries. But it helps us to look for other things like lung disease, emphysema, fibrosis of the lungs, or congestive heart failure. But it’s not again, by itself, not a good enough test to say that the disease is present or what the cause is.
After that, we typically do a good deal of blood work when we’re assessing someone for shortness of breath for common things that make people short of breath, such as anemia and liver disease and kidney disease. Once you have those tests, they help sort of filter out some of the other things that are more common than pulmonary hypertension.
Most of our patients undergo an echocardiogram and that’s the common pathway where most patients, the diagnosis of pulmonary hypertension is suggested. An echocardiogram is an ultrasound of the heart. It’s really good at looking at the structures of the heart although it can be made less effective by things like lung disease and obesity. But that echocardiogram is where most patients get the original thought that they might have pulmonary hypertension because they either have enlargement of the heart or the estimated blood pressure in the lungs is elevated.
Once we have that piece of information in a patient with the appropriate symptoms, i.e. shortness of breath or fatigue or swelling, fainting, then the testing for pulmonary hypertension becomes a little more specific. We can divide those really into a couple of different groups. There’s blood tests and we look for the common causes of pulmonary hypertension or pulmonary arterial hypertension that we can detect by a blood test for things, for example, like HIV, liver disease including hepatitis, connective tissue diseases by using tests like the antinuclear antibody, which is a test for lupus or a more specific test for diseases like scleroderma. We also at that time typically will get blood tests that help us to follow the patient if they do in fact have pulmonary hypertension, things like a hormone called the proBNP or the BNP which is a hormone that goes up when your heart is struggling or is not meeting your demand that you have. We also often check for thyroid testing as well because thyroid disease is associated with pulmonary hypertension to some degree.
Then there’s x-rays and the types of x-rays that people typically get include a CAT scan of the chest, which is a really good test to look at the structures of the chest. It shows us the size of the pulmonary artery. It shows us the spaces between the lungs and are the lymph nodes enlarged? What do the blood vessels coming out of the heart look like? Are they enlarged? Is the heart size normal or enlarged? Is the sac around the heart normal. Then it’s probably the best way to look at the actual lung tissue and say there’s an underlying lung process, like scarring of the lung or pulmonary fibrosis or emphysema from COPD.
One of the most important x-ray tests that we can get is called a V/Q scan. Now a CAT scan can be used to look for blood clots and it’s a very good test to look for new blood clots or blood clots that have just occurred. It’s not quite as good at detecting old blood clots, which are more like scarred tissue. So the V/Q scan is often done as a test to look for evidence of old blood clots. What a V/Q scan is is an x-ray where you breathe in a gas that we can detect with a camera and we see where the air goes. Everywhere air goes blood should follow. If there are areas where there’s air but no blood, that suggests that something’s blocking the blood flow like a blood clot. When we see that, then we’ll then move to the next test. If the V/Q scan and/or CAT scan suggests old blot clots, then often patients will get something called a pulmonary angiogram where we directly squirt dye into the pulmonary arteries to assess for the location of blockages and is a minimal to a surgery that might fix pulmonary hypertension.
This test, this V/Q scan, is a very simple test, but it’s one of the more common tests that’s not done in patients with suspected pulmonary hypertension. Sometimes it’s because people aren’t thinking about blood clots as a cause. Sometimes it’s because a CAT scan’s been done and it didn’t show evidence of clots. But usually what I ask patients, I said, “If you had the choice, if you were diagnosed with a disease and you said there’s one kind of disease that is potentially curable, we can usually detect it with a simple x-ray that has very little risk to you, would you want that test?” I think most patients would say, “Sign me up. I want that test right now.” But in our world, the V/Q scan, which is that test looking for old blood clots is very often left off of the diagnostic evaluation. We hope to change that.
Then the most important test to confirm a diagnosis of pulmonary hypertension, not to detect it but to confirm that it’s there, is called a right heart catheterization. A right heart catheterization is a test where either a lung doctor or a cardiologist will take a plastic tube with a balloon on the end of it and using an x-ray, we will go in through one of the larger veins in the arm or the neck or the leg to go up and measure the blood pressure in the lungs. That’s really important because all of our other mechanisms for determining whether someone has high blood pressure in the lungs, they’re just estimates. They’re not actual measurements of the blood pressure and they may be spot on or they may be very far off. The right heart catheterization enables us to measure the pressures directly.
It’s a crucial step in the diagnosis because one, we want to absolutely know that the patient has pulmonary hypertension and two, it also is the best way that we have at present to separate out the Group 1 patients, patients with pulmonary arterial hypertension and patients with Group 2 or left heart failure associated pulmonary hypertension. The right heart catheterization is able to do that for us. It also gives us really important information to help us pick the right kind of therapy for an individual patient. It can give us really good information about prognosis. Now sometimes when you have the right heart catheterization, it’s not completely clear and we may do maneuvers like fluid challenges or exercise challenge or a medication challenge to see what the best approach to your particular disease would be. But it’s still absolutely required in the evaluation of pulmonary hypertension.
Really the last test that we do, and it’s not routinely done but is often done, is an MRI of the heart or blood vessels. The MRI of the heart is a really good way to look at the structures of the heart. We usually do that in one of two circumstances. Either we’re looking for an abnormality of the structures of the heart, such as a hole in the heart either in the top chambers, called an atrial septal defect or in the bottom chambers, called a ventricular septal defect. Or we sometimes use it to help us quantify or estimate or determine how efficiently the heart is working. It can give us really important information about how the heart functions and gives us guidance about how to intervene to help the patient do better.
I’m Victor Test and I’m Aware That I’m Rare.
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