Mechanisms of hypoxaemia in severe pulmonary hypertension associated with COPD.

Pulmonary hypertension (PH) is a frequent complication of chronic obstructive pulmonary disease (COPD) with poor prognosis, especially in its severe form [1]. Accordingly, current guidelines distinguish patients with severe PH from those with moderate PH [2]. Patients with COPD and severe PH often present with worse hypoxaemia than those with moderate PH, despite having milder airflow obstruction [3–5]. The mechanisms underlying severe hypoxaemia in these patients have not been elucidated. This study aimed to analyse the determinants of hypoxaemia in severe PH associated with COPD by assessing ventilation-perfusion (VA/Q) relationships with the multiple inert gas elimination technique (MIGET). Footnotes This manuscript has recently been accepted for publication in the European Respiratory Journal . It is published here in its accepted form prior to copyediting and typesetting by our production team. After these production processes are complete and the authors have approved the resulting proofs, the article will move to the latest issue of the ERJ online. Please open or download the PDF to view this article. Conflict of interest: Lucilla Piccari has received research funding from and served as a speaker for Janssen-Cilag and Ferrer International, participated in advisory boards for Janssen-Cilag, Ferrer International and United Therapeuthics as well as received support for attending congresses from Janssen-Cilag, Merck Sharp & Dome and Ferrer International, all of which not related to this manuscript. Conflict of interest: Isabel Blanco reports lecture honoraria from Janssen, MSD and Ferrer; outside the submitted work. Yolanda Torralba reports lecture honoraria from TEVA; outside the submitted work. Conflict of interest: Felip Burgos reports consulting fees from Scientific Advisory Board Medical Graphics Diagnostics, outside the submitted work. Conflict of interest: Roberto Rodríguez-Roisín reports grants from CHIESI Spain, outside the submitted work. Conflict of interest: Joan Albert Barberà reports consulting fees from Merck Sharp & Dome, Janssen-Cilag, Acceleron Pharma; lecture honoraria from Ferrer International, Janssen-Cilag, Merck Sharp & Dome; travel support from Merck Sharp & Dome, Janssen-Cilag; outside the submitted work. All other authors have nothing to disclose.