Valerie McLaughlin, MD - phaware® interview 219

Feb 8, 2019

Vallerie McLaughlin, MD from Michigan Medicine's Cardiovascular Center discusses what a pulmonary hypertension patients should expect in their first visit to an expert PH Center. Dr. McLaughlin is the Director of the Pulmonary Hypertension Program at the University of Michigan in Ann Arbor. She is a Fellow of the American College of Cardiology, American College of Chest Physicians, and American Heart Association (AHA). Dr. McLaughlin has been the Principal Investigator of several major clinical trials of drug therapies for pulmonary arterial hypertension and has published numerous papers in this field.

Hi. I'm Vallerie McLaughlin from the University of Michigan. I direct the pulmonary hypertension program there and today it's my pleasure to talk to you a little bit about what to expect once you get to an expert [pulmonary hypertension] center.

Most patients get referred to us often after having seen a number of physicians for shortness of breath, often with an echocardiogram that shows an elevated pulmonary artery pressure. Now, one thing that's really important to remember is that the echocardiogram is just an estimate of pulmonary artery pressure and there's much more to an echo than just the pulmonary artery pressure. We look at the size and function of the right ventricle.

It's very often that the symptoms of pulmonary hypertension are nonspecific and that means those symptoms could occur in many different diseases; shortness of breath, fatigue, chest discomfort and the like. It's important for us to look for other causes of such symptoms; things like lung disease, COPD, and pulmonary fibrosis. Oftentimes a patient get testing on their lungs like pulmonary function tests or a chest CT scan or a study for obstructive sleep apnea. That's really important to look for.

Sometimes patients have other heart problems; their left heart, their ventricles don't squeeze well or don't relax well or there's a problem with the valves on the left side of the heart. That's actually a very common cause of pulmonary hypertension. Sometimes patients have blood clots in the lungs that cause pulmonary hypertension and so doing a ventilation/perfusion scan to rule that out is important.

After we've looked for all of these other causes, and there are many more besides the ones I mentioned, we want to confirm a diagnosis of pulmonary hypertension. That requires a right heart catheterization. A right heart catheterization is a study that is done usually in a cardiac catheterization lab during which we put a small catheter in a blood vessel, often in the neck or in the groin area. We thread that catheter to the heart and we measure the pressure in the different chambers of the heart and lungs and how the blood flow goes through the lungs.

Sometimes when we do this, we learn that the problem is on the left side of the heart, that the patient has pulmonary hypertension because the left heart is sending too much pressure back to the lungs. Sometimes we learn that the patient has what we call pulmonary arterial hypertension. PAH is high pressure in the lungs with an elevated pressure and elevated resistance across that vascular bed in the lungs and no other heart or lung disease. That can be idiopathic. It can be hereditary, or it can be due to some other diseases such as connective tissue diseases like scleroderma or lupus. Occasionally, it's due to liver disease. Sometimes it's due to holes in the heart. Occasionally, it's due to different drugs and toxins like diet pills or methamphetamines. But the right heart catheterization is absolutely required for the diagnosis.

Oftentimes, we'll try to get an assessment of how sick a patient is; what their risk level is. Not just from the numbers we measure on the catheterization, but also things like BNP, a blood test to determine stress on the heart, and how far the patient can walk in some sort of exercise tolerance test, often a six-minute hall walk. So once the diagnosis is complete, let's say that we have ruled out the other heart diseases that can do this, the other lung diseases that can do this, and we're calling the patient Group I pulmonary arterial hypertension; we decide what treatment is best for them based on their risk status and again, that involves a number of different factors.

There are medications that generally belong to three different groups that are now FDA approved to treat pulmonary hypertension. The prostacyclin pathway and medications in this pathway come in oral, inhaled and subcutaneous (under the skin), and IV into the vein forms. There is the nitric oxide pathway. In this pathway, are the PDE5 inhibitors and the sGC stimulators. These are oral therapies. {Also, there's} the endothelin receptor pathway. These are oral therapies, as well.

In the very sickest of the sick patients, the patients who come to us with very advanced symptoms who have heart catheterization numbers signifying advanced disease with a high right atrial pressure and a low cardiac index, we often go straight to the parenteral prostacyclin therapies. {These are] the IV therapies and the under-the-skin therapies, often in combination with oral agents, as well. We feel those patients are at such high risk that we really need to be very aggressive with their therapy. In our experience at the University of Michigan, I would say that's probably about 10% of the new PAH patients that we see. So it's not the majority, but there are certainly patients that fall into that category.

I would say the majority of newly diagnosed patients that we see now start on dual oral therapy and that's usually the combination of an endothelin receptor antagonist and a PDE5 inhibitor based on clinical trials. It's very remarkable the improvement that patients have with up-front oral combination therapy compared to just one medication at a time. I would say that has now become the standard when we see patients that are newly diagnosed who are in either the low or the moderate risk range. There are some opportunities to use just one medication and those are few and far between. In fact, my approach now is there needs to be a really good reason to start with only one medication as opposed to use two at the time of diagnosis.

This first treatment [information] is really just that, just the first step. After you make the first treatment decision, it's really important to continue to monitor the patient to see how they do and continue to adjust their medications to try to get them into that very lowest risk status.

This is Vallerie McLaughlin from the University of Michigan and that's a little summary of what might happen to a patient after they've been referred to a pulmonary hypertension center.

Learn more about pulmonary hypertension at www.phaware.global Never miss an episode with the phaware® podcast app. Follow us @phaware on Facebook, Twitter, Instagram, YouTube & Linkedin Engage for a cure: www.phaware.global/donate @umichmedicine @umichCVC @antidote_me @accpchest  #phaware #phawareMD