Classification and course of pulmonary hypertension associated with end-stage COPD.

Background: Pulmonary hypertension (PH) associated with COPD contributes to morbidity and mortality. Further characterisation to improve management is warranted. The aim of the study was to apply the recently proposed PH classification and to assess the association of lung volume involvement and PH over the course of disease in patients with advanced COPD. Methods: Patients with COPD undergoing transplant evaluation, including right heart catheterisation were included irrespective of the likelihood of having PH. Spirometry, plethysmography and computed tomography were used to assess the degree of parenchymal and vascular involvement. Follow-up investigation was performed for 18±12 months. The 2022 European Society of Cardiology/European Respiratory Society guidelines were used for classification of PH. Results: In total, 340 patients were included and 639 right heart catheters were assessed. The majority of patients were classified as no PH (n=131, 38%) or nonsevere PH (n=133, 39%), whereas severe COPD-PH was present in 26 patients (8%). Patients with severe COPD-PH had similar degrees of airflow obstruction but lower lung volumes. Further, pulmonary vascular resistance (PVR) correlated negatively with residual volume. Interstitial lung abnormalities were present in 11 patients (3%) and scattered across all PH groups. Follow-up (n=141, 41.5%) demonstrated a low rate of deterioration to severe COPD-PH (4%). However, an increase of PVR was common and was associated with a decrease of total lung capacity. Conclusion: Unbiased longitudinal invasive follow-up and assessment of lung volumes by plethysmography provided evidence of an association of lung volume and PVR.