Usefulness of ventilatory gas analysis for the non-invasive evaluation of the severity of chronic thromboembolic pulmonary hypertension

Abstract Background Chronic thromboembolic pulmonary hypertension (CTEPH) is characterized by organic thrombotic obstructions in the pulmonary arteries with reduced pulmonary vascular reserve. This study aimed to examine whether postural changes in ventilatory gas analysis parameters are useful for assessing pulmonary hemodynamics in patients with CTEPH. Methods A total of 44 patients with newly diagnosed CTEPH (CTEPH group), 33 patients with improved CTEPH (mean pulmonary arterial pressure [mPAP] Results Patients with CTEPH had significantly lower supine end-tidal carbon dioxide pressure (P ET CO 2 ) and ΔP ET CO 2 than controls (both P 2  = 0.507, P 2  = 0.470, P ET CO 2 and ΔP ET CO 2 were significantly lower in patients with improved CTEPH than in controls (both P ET CO 2 by BPA was noted (R 2  = 0.478, P Conclusion These results indicate that postural changes in ventilatory gas analysis parameters are useful and non-invasive method for the evaluation of mPAP, which is one of the hemodynamic parameters of CTEPH severity.