Pulmonary hypertension in interstitial lung disease and in chronic obstructive pulmonary disease: different entities?

Purpose of review Pulmonary hypertension (PH) is a common complication of both chronic obstructive pulmonary disease (COPD) and interstitial lung disease (ILD), classified as Group 3 PH. To which extent PH presents and behaves similarly in COPD and ILD is unclear. This review examines the similarities and differences in pathogenesis, clinical presentation, natural history and treatment response of PH in COPD and ILD. Recent findings The latest studies on PH in chronic lung disease have re-evaluated the role of traditionally held etiopathogenetic factors such as tobacco exposure and hypoxia, although new ones such as airborne pollutant and genetic mutations are increasingly recognized. We examine common and diverging factors involved in PH development in COPD and ILD, as well as common and diverging clinical features of presentation, natural history and response to treatment and highlight areas for future research. Summary The development of PH in lung disease significantly worsens the morbidity and mortality of patients with COPD and ILD. However, recent findings show importance of recognizing distinct patterns and behaviors of pulmonary vascular disease, taking into account the specific underlying lung disease and severity of the hemodynamic involvement. Further studies are needed to build evidence on these aspects, especially in early disease.