Cardiopulmonary exercise testing appears safe in high-risk patients with established cardiovascular diagnoses

Cardiopulmonary exercise testing appears to be safe in patients with high-risk cardiovascular diseases, according to a new study.

Researchers performed a single-center retrospective review of cardiopulmonary exercise testing in a heterogeneous cohort of high-risk patients to determine its safety in this population. A total of 5,060 exercise tests in 4,250 unique patients were included. The primary end point of the study was occurrence of major adverse events during exercise testing. Results were published online Oct. 22 by Circulation.

Of the 4,250 patients, 1,748 (35%) were women and 686 (14%) were age 75 or older, with a mean age of 57.0 ± 15.9 years. High-risk cardiac diseases included congestive heart failure (n=1,289, 25.5%), hypertropic cardiomyopathy (n=598, 11.8%), pulmonary hypertension (n=194, 3.8%) and aortic stenosis (n=212, 4.2%).

Symptom-limited exercise testing was completed in most patients (94.5%), who stopped because of fatigue, dyspnea or chest pain. Testing was stopped in the remaining 5.5% because of patient request, electrocardiogram changes, abnormal blood pressure response or major adverse event.

A total of 1,192 patients (24%) were found to have a peak VO₂ below 14 mL/kg/min, indicating severe functional impairment. The rate of adverse events during cardiopulmonary testing was 0.16%, most commonly ventricular tachycardia (six of eight events). No patients died during testing.

The authors noted that although many of the disorders present in their study population are usually considered contraindications to exercise testing, adverse event rates were low, and none occurred in patients with hypertrophic cardiomyopathy, pulmonary hypertension or aortic stenosis.

They also said that cardiopulmonary exercise testing is the recommended method for determining cardiovascular disability but is usually not done in high-risk patients because of safety concerns. Their study, they said, should help change that practice.

The results have limited generalizability because the study was performed at only one center, and data on disease severity were not available for all study participants, among other limitations, the authors wrote.

They also stressed that all of the patients in their study had established cardiovascular diagnoses, that tests were carefully performed at an experienced tertiary care center, and that some patients with severe forms of cardiac disease should never undergo exercise testing.

However, they wrote, “for other patients with these disorders, [cardiopulmonary exercise testing] appears to be reasonably safe and can serve as a helpful aid in the management of these patients.” Further study in a larger population is needed to determine which patients have the greatest risk of an adverse event during testing, they concluded.