New study will explore impact of exercise on pulmonary hypertension

Aug. 26, 2011

For sufferers of pulmonary arterial hypertension (PAH), maintaining healthy heart function isn't as simple as going for a jog every morning. Patients need to do all they can to slow damage to their heart, and exercise can potentially improve their quality of life.

On the other hand, the demands of pumping blood into stiff, large arteries and narrowed small arteries means that many PAH patients bear an increased risk of overexertion, which makes prescribing the correct amount of physical activity difficult.

Now, a University of Wisconsin-Madison biomedical engineer and colleagues hope to clear up that uncertainty in a new study seeking to quantify the impact of exercise on PAH patients.

Funded by a four-year, $2.5 million grant from the National Institutes of Health, Naomi Chesler, an associate professor of biomedical engineering at UW-Madison, will investigate the relationships between small artery narrowing, large artery stiffening and their interactions with the right side of the heart in patients with PAH.

"Most patients with pulmonary hypertension die from right heart failure, so even though the disease may be initiated in the small arteries of the lung, the impact on heart function is what's really critical," says Chesler.

Establishing how these factors relate to one another will allow Chesler and her team to develop a way of identifying PAH patients who can most benefit from regular exercise.

The objective will be finding identifiers that separate PAH patients who will benefit from exercise from those whose condition will worsen from it.

"We're trying to differentiate those people who have sufficiently good interactions between the heart and the lungs from those where the heart and lungs are not working well together," Chesler explains.

The study also builds upon Chesler's work on a previous NIH grant in which she researched how the presence of excess collagen, a fibrous protein found in connective tissues throughout the body, might contribute to pulmonary hypertension. "We're dovetailing our previous work on the role of collagen in large artery stiffening with new work on the impact of large artery stiffening on heart function. An important patient population in our new study is those with a collagen disorder," Chesler says.

Of particular interest in the study will be patients with scleroderma, or systemic sclerosis (SSc),a disease caused by excess collagen accumulation throughout the body, including blood vessels. Patients with SSc-related PAH don't have a lot of effective treatment options, but focusing on such patients in the study might identify their best treatment options.

Chesler's UW-Madison collaborators include Heidi Kellihan, clinical assistant professor in the School of Veterinary Medicine; Jim Runo, assistant professor of pulmonary medicine; Chris Francois, assistant professor of radiology; and Jens Eickhoff, biostatistics and medical informatics senior scientist. Mardi Gomberg-Maitland, an expert in pulmonary hypertension from the University of Chicago, is a consultant on the study, and Sanjiv Shah at Northwestern University will be conducting many of the patient studies, due to the large PAH patient population in Chicago.

– Mark Riechers