Exercise intolerance after pulmonary endarterectomy common in CTEPH

Exercise intolerance was common among patients with chronic thromboembolic pulmonary hypertension, or CTEPH, after undergoing pulmonary endarterectomy, despite hemodynamic normalization, according to researchers.

“While mortality and residual pulmonary hypertension at rest are the most commonly reported outcome measures after pulmonary endarterectomy, few studies have focused on exercise capacity,” Dieuwertje Ruigrok, MD, of the department of pulmonary medicine at the University of Amsterdam, and colleagues wrote in a study published in European Respiratory Journal.

Researchers conducted a prospective cohort study of 68 patients who underwent cardiopulmonary exercise testing, right heart catheterization and cardiac MRI before and 6 months after pulmonary endarterectomy. Exercise intolerance was defined as peak oxygen consumption of 80% or more predicted. The researchers evaluated cardiopulmonary exercise testing parameters to determine the cause of patients’ exercise limitation, and also analyzed associations between exercise intolerance, resting hemodynamics and cardiac MRI-derived right ventricular function.

Of 68 patients, 45 (66%) had exercise intolerance 6 months after pulmonary endarterectomy, with exercise intolerance primarily caused by a cardiovascular limitation in 20 of these patients. Patients with persistent exercise intolerance had higher incidence of residual pulmonary hypertension (P = .001). Of 45 patients with persistent exercise intolerance, 27 had no evidence of residual pulmonary hypertension, according to the results.

Multivariate analysis showed that preoperative transfer factor of the lung for carbon monoxide was the sole predictor of exercise intolerance in patients after pulmonary endarterectomy.

According to the researchers, cardiopulmonary exercise testing provides clinically meaningful outcome parameters in patients with CTEPH after undergoing pulmonary endarterectomy.

“While persistent exercise intolerance was mainly determined by a cardiovascular limitation, not all exercise intolerance could be explained by the presence of residual pulmonary hypertension,” the researchers wrote. “A lower preoperative transfer factor of the lung for carbon monoxide serves as a strong predictor of persistent exercise intolerance after pulmonary endarterectomy. Transfer factor of the lung for carbon monoxide, thereby, provides an easily accessible marker to predict the functional response to pulmonary endarterectomy in CTEPH.”