Michael Keller, MD - phaware® interview 295

Michael Keller, MD is a Pulmonologist and Pulmonary Hypertension specialist with Suburban Lung Associates in Elk Grove Village, IL. He is medical director of the AMITA Health Pulmonary Hypertension
program.

In this episode, Dr. Keller discusses the importance of exercise in Pulmonary Hypertension.

His clinical interests include the full spectrum of pulmonary vascular diseases with a focus on pulmonary hypertension in chronic lung disease. He serves as medical director of the Alexian Brothers
Pulmonary Rehabilitation Program.

I am Michael Keller. I am a pulmonologist with Suburban Lung Associates with AMITA Health in the northwest suburbs of Chicago.

Today, I'd like to spend some time talking about the role of exercise in pulmonary hypertension.

We know the benefits of regular physical activity are tremendous for all people. We all recognize that there's a significant cardiovascular benefit. Regular exercise can reduce the risk of stroke, of developing diabetes, of developing high blood pressure. There's also significant benefit in reducing the risk of certain cancers like colon cancer. We know regular exercise can help improve people's mood and reduce feelings of depression and anxiety. So there's many benefits for healthy patients and patients with different cardiovascular diseases.

When we look at the body's response to exercise in the setting of a normal heart, we see that that heart squeezes out up to four to five times as much blood during a state of exercise compared to when it's at rest. The reason it needs to do that is to deliver extra oxygen to the exercising skeletal muscles. We know that the blood pressure increases to help facilitate this, as well. When you look at the blood flow through the pulmonary arteries in the lung, when the heart is pushing out more blood to accommodate the exercising muscles, the resistance to blood flow in those arteries in the lungs actually decreases to help facilitate that, and it leads to only a mild increase in blood pressure in the lungs during exercise.

When you look at a patient with pulmonary arterial hypertension, the underlying problem is an increased resistance to blood flow in the arteries in the lungs. When you begin to exercise, and your muscles demand more oxygen, and your heart wants to pump out more blood, you become limited by that increased resistance to blood flow through the lungs. The right side of the heart is not able to get as much blood through the lungs to the left side of the heart, and to allow the left side of the heart to then pump that blood out to your muscles, which leads to the symptoms of shortness of breath with activity or with exercise. At a more advanced state, can even lead to symptoms of lightheadedness with exercise or chest pain.

So there is another limitation in patients with pulmonary arterial hypertension, in that we know their muscles, their skeletal muscles, the big muscles in their legs, in their arms, do not function as well as somebody without pulmonary arterial hypertension. This has been looked at by taking small biopsies of those muscles. When you compare them, the muscles in a patient with pulmonary arterial hypertension are generally more atrophied and smaller. Their contractile strength is not as strong. There's a lower number of the muscle fibers that we use for endurance activities. We also know that these muscles tend to change the way they process energy, and they start making acid that builds up in your blood sooner than a patient without pulmonary arterial hypertension.

If we look at our current recommended treatment algorithm for patients with pulmonary arterial hypertension, a supervised exercise training is a recommendation for all patients. There used to be concern years ago that exercise for patients with pulmonary arterial hypertension could potentially be dangerous. It's really been over the recent years that we've recognized it's not only safe, but has significant clinical benefit as well.

There've been a number of small studies, usually only 20 to 30 patients, looking at the role of exercise in pulmonary arterial hypertension or in patients with CTEPH. There was a group that took all of these small studies and put them together in a systematic review, and [they] came to the conclusion that in patients who are stable on their current medication, a supervised exercise training protocol leads to a significant improvement in their six-minute walk distance. The amount that that walk distance improved is actually greater than nearly every single trial of a drug that led to an approved new therapy. It showed that the muscles were able to uptake more oxygen after an exercise training program. What patients care about most is that it led to an improved quality of life. Importantly, there were no major adverse events. In a stable patient undergoing a supervised program, we've learned that it's safe, that exercise is not dangerous.

There was also another study done, in which they actually measured the function of the heart and the resistance to blood flow through the lungs before exercise and after a supervised exercise program. This protocol was fairly intense, and that the patients were in the hospital for the first three weeks, and then followed at home with a continued exercise program for another 12 weeks. Again, all of these patients were stable on their therapies, between one to three different drugs. What they showed was that at the end of that exercise training program that the heart was able to pump out a significant more amount of blood. The resistance to blood flow through the arteries in the lungs had reduced. This led to a reduction in the mean pulmonary artery pressure in the lungs as well. Additional evidence of the significant benefits of exercising and improving the condition of the skeletal muscles, not only on how patients feel and their quality of life, but actually on how the heart and lung function. Although we've shown over recent years that exercise can be safe and effective adjunctive therapy on pulmonary arterial hypertension, we do still approach each patient individually and with caution.

Again, before anyone begins any type of exercise routine, they really need to talk with their PH care team to understand what is safe for them and what sort of limitations they should have in place. Some general limitations that we talk about are not over exerting yourself. I often tell my patients to follow, they listen to their bodies. We recommend sort of a symptom limited exercise program. Then if any of these concerning symptoms, such as lightheadedness, chest pain, racing heart, or excessive shortness of breath develop that that's a little too intense of a regimen. They need to take a break and slow it down. We generally recommend avoiding very strenuous exercise, such as heavy lifting, that requires you to really bear down, or again, anything that involves a very intense aerobic exercise routine.

One other caution that we often bring up is to avoid exercises that involve significant movement of both your arms and your legs at the same time, because the amount of extra demand on the heart that that will create. I generally recommend an aerobic exercise training program that can involve simple walking, working on a treadmill, exercise bike, an elliptical, other forms of exercise such as yoga, Pilates. Swimming can be safe and effective as well, as well as light resistance training. Again, we recommend avoiding heavy lifting that results in you really holding your breath and bearing down, but light resistance training can help improve your muscle strength and endurance, as well.

How this can be accomplished is coming up with a program that you can do on your own, or if you have access to a fitness center, or a gym where you can exercise. There are some formal exercise programs, as well, that can be offered through a hospital setting, which is a pulmonary rehab or a cardiac rehab program. The limitation for pulmonary hypertension patients is that pulmonary hypertension is currently not a diagnosis that is covered by Medicare and many private insurances for completing a pulmonary rehabilitation program. Some of our patients who have comorbid or other lung diseases, such as COPD, we may be able to qualify. Some of our patients have abnormalities on their pulmonary function test that will allow them to qualify under their Medicare guidelines, although they don't have a diagnosis of COPD or another lung disease. These formal pulmonary rehabilitation programs are nice because they are supervised by trained nurses and therapists. In addition to the exercise routine, they generally include some group education as well, which focuses on nutrition, oxygen therapy. You're meeting other patients with pulmonary hypertension, other lung diseases, and it ends up being a good support group, as well.

In summary, we know now that exercise is safe for pulmonary arterial hypertension patients when done with certain limitations in place. They can lead to significant benefit in how patients feel, even in improvements in the function of their heart. Again, I'll stress the importance of being sure that everyone talk with their treating care team before beginning an exercise routine, so they do know what is safe for them and what sort of limitations they should include in their exercise program.

My name is Dr. Michael Keller, and I'm aware that I'm rare.

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