Impaired Pulmonary Vascular Adaptation to Exercise in Emphysema without Pulmonary Hypertension – A Proof-of-Concept Study

Abstract Background: Chronic obstructive pulmonary disease with emphysema lead to respiratory disability beyond bronchial obstruction. The functional impact of pulmonary vascular lesions in emphysema remains unknown. We investigated pulmonary vascular adaptation to exercise in patients with extended emphysema.Methods: Chest magnetic resonance imaging was used to quantitatively assess right-heart function, pulmonary artery and distal pulmonary blood flow. This was performed at rest and during cycling exercise with a magnetic resonance imaging-compatible cyclo-ergometer. Seven emphysematous patients without pulmonary hypertension were compared to 7 healthy non-smokers matched in gender and age.Results: At rest, cardio-pulmonary hemodynamics and distal pulmonary vascular parameters were similar in both groups. Intrasubject adaptation to exercise in emphysematous patients was characterized by a higher increase in right-ventricular ejection fraction (ΔRVEF +8.1 vs. -2.4 %, P=0.046) though a lower right-cardiac output (4.41 vs. 5.79 L/min, P=0.04) at exercise. Accounting for right-cardiac output variation, the distal pulmonary vascular yield index trended to be decreased in patients (ΔPBF/ΔQf -0.78 vs. +18.83 %, P=0.18).Conclusions: Pulmonary vascular adaptation to exercise is impaired in emphysematous patients without identified pulmonary hypertension.Clinical trial registration NCT 04126616.