FIGURE 1.

Major components of the updated classification of group 3 pulmonary hypertension (PH). Chronic lung diseases (CLDs) encompass a wide range of parenchymal processes which often have unique pathogenetic mechanisms and clinical presentations. Recent literature demonstrates that there are important pathogenic differences contributing to PH complicating different CLDs, which is likely to impact how these entities respond to therapy. These considerations led to a change in classification of group 3 PH that placed COPD, interstitial lung disease (ILD), combined pulmonary fibrosis emphysema (CPFE) and other parenchymal lung diseases in different categories, in addition to developmental lung diseases, nonparenchymal restriction and hypoxia without lung disease (which are not represented on the figure). Making a diagnosis of CLD-PH requires a multimodal approach, with particular emphasis on a high-quality radiographic assessment.