Ventilatory Efficiency During Exercise in CTEPH and PAH Pre- and Post-Treatment.

Area of Science:

• Cardiopulmonary medicine
• Pulmonary hypertension research
• Exercise physiology

Background:

• Ventilatory inefficiency, measured by VE/VCO2 slope, is a key marker in cardiopulmonary exercise testing (CPET).
• Characterizing differences in ventilatory efficiency between chronic thromboembolic pulmonary hypertension (CTEPH) and pulmonary arterial hypertension (PAH) and their treatment responses is crucial.

Purpose of the Study:

• To compare ventilatory efficiency between CTEPH and PAH patients using CPET.
• To identify predictors of ventilatory efficiency in these conditions.
• To evaluate the impact of treatment on ventilatory efficiency in CTEPH and PAH.

Main Methods:

• Retrospective analysis of CPET data from 92 CTEPH and 91 PAH patients.
• Comparison of VE/VCO2 slope and peak oxygen uptake (peak VO2) at baseline and in treatment-naïve subgroups.
• Regression analyses for predictor identification and evaluation of longitudinal changes post-treatment.

Main Results:

• CTEPH patients exhibited significantly worse ventilatory efficiency (higher VE/VCO2 slope) than PAH patients at baseline, despite less severe hemodynamics.
• Pulmonary vascular resistance, mean pulmonary artery pressure, and peak VO2 independently predicted VE/VCO2 slope in both groups.
• Treatment led to significant improvement in ventilatory efficiency in CTEPH, most notably after pulmonary endarterectomy, with less pronounced changes observed in PAH patients receiving targeted therapy.

Conclusions:

• Ventilatory inefficiency is more severe in CTEPH compared to PAH, irrespective of resting hemodynamics.
• CPET-derived ventilatory efficiency demonstrates substantial improvement post-treatment in CTEPH, particularly after pulmonary endarterectomy.
• VE/VCO2 slope serves as a valuable non-invasive indicator of treatment response in pulmonary hypertension, especially in CTEPH.