Cardiopulmonary Exercise Testing for Diagnosing and Managing PH

In this podcast, Aaron Waxman, MD, PhD, discusses the role of exercise hemodynamics in the diagnosis and treatment of pulmonary hypertension and the types of exercise that are best for patients with pulmonary hypertension.

Aaron B. Waxman, MD, PhD, is the executive director of the Center for Pulmonary Heart Disease and the director of the Pulmonary Vascular Disease Program at Brigham and Women’s Hospital and is associate professor of medicine at Harvard Medical School in Boston, Massachusetts.

Additional Resource:

• Waxman A. The role of exercise hemodynamics in the diagnosis and treatment of pulmonary hypertension. Talk presented at: 4th Annual Advances in Pulmonary Hypertension; August 2, 2019: Chicago, IL. https://bit.ly/2KtC2f6. 

TRANSCRIPT:

Aaron Waxman:  Hi, my name is Aaron Waxman. I am the executive director of the Center for Pulmonary Heart Disease and the director of the Pulmonary Vascular Disease Program at the Brigham and Women's Hospital in Harvard Medical School in Boston, Massachusetts.

I'm going to be talking about my session at the Fourth Annual Advances in Pulmonary Hypertension Meeting to be held in Washington, DC. The focus of my discussion is going to be about using cardiopulmonary exercise testing in the evaluation and management of patients with pulmonary hypertension.

Exercise testing in general has a broad application to patients with pulmonary hypertension. Importantly, with any form of exercise testing, one has to understand what you can gain from that but also what the limits of the testing are. With invasive hemodynamics during exercise it gives us a window into basic physiology of what's happening in patients with especially early forms of disease. It allows us to accurately detail what limitations there are from a cardiac, cardiopulmonary, pulmonary vascular, neuromuscular, and metabolic influences on patients' ability to exercise.

One of the fundamental things we have been focusing on in our Pulmonary Vascular Program at the Brigham is the earlier diagnosis of disease. In many cases, patients start to complain of shortness of breath, or fatigue, or some form of exercise limitation before there's obvious findings on standard testing like echocardiography, even right‑heart catheterization.

When we exercise patients with hemodynamic assessment at the same time, the goal is to reproduce the symptoms the patient is having and evaluate their physiological response to that exercise. With that, we've been able to detail the earliest phases of disease, and have shown in previous work that if we treat patients at that earliest phase, we can actually see improvement in their hemodynamic abnormalities and improvement in their exercise tolerance.

There's also approaches to using non‑invasive exercise to get a sense of how a patient is progressing or how a patient is responding to treatment. What we've made use of is maximal exercise as well as submaximal exercise testing as routine measures of patient response to treatment, which can often be much more informative than the traditional six‑minute walk test or asking a patient how they're doing.

Something we didn't touch on was exercise prescriptions for patients. We encourage all patients with pulmonary vascular disease that once they're in a program of medical management, there should also be exercise or rehabilitation for them to build not only strength but also endurance.

A well‑prescribed exercise program should include resistance training as well as aerobic training. There are a growing number of studies that suggest that those applications can be just as effective as medications. When we combine the two, medication and exercise, patients tend to do much better.

There are a couple of key take home points. One, the main question of why consider invasive cardiopulmonary exercise testing. Importantly, hemodynamic assessments are often done at rest with the patient in a supine position and that's not how they actually live. All of us live in an upright position. The goal of doing invasive hemodynamics is to mimic the activities of daily living when our patients are likely symptomatic.

The other key thing is that there are limits to non‑invasive exercise testing as far as being able to make accurate diagnoses, but they're very powerful as far as making accurate assessments of how patients are doing.

I want to thank you all for listening to what I had to say today. If there's additional interest or a need for additional information, please review the links below.