Abstract
The revised definition of pulmonary hypertension (PH) reclassifies patients previously diagnosed with chronic thromboembolic pulmonary disease (CTEPD) without pre-capillary PH as having chronic thromboembolic pulmonary hypertension (CTEPH). Reclassified CTEPH patients demonstrated oxygen desaturation during exercise and reduced ventilatory efficiency, as patients with more severe CTEPH, indicating impaired exercise physiology. These findings support the data of prior studies and the clinical relevance of the newly defined hemodynamic thresholds in patients with CTEPH.