[Pulmonary hypertension associated with lung disease]

Pulmonary hypertension (PH) is a multifactorial pulmonary vascular disease. PH associated with pre-existing lung disease is common and classified as group 3 in the clinical classification. Patients with chronic obstructive or interstitial lung disease are most likely to develop PH, with up to 20% of patients showing signs of PH. Distinguishing between the symptoms of the underlying lung disease and concomitant PH can be difficult. Clinical assessment, lung function tests, laboratory tests, and echocardiography can be helpful. The hemodynamic definition of PH has recently been changed. PH associated with lung disease is a pre-capillary form by definition. A special sub-stratification in group 3 is the differentiation of hemodynamic severity. Severe PH in group 3 is defined as a pulmonary vascular resistance (PVR) greater than 5 Wood units (WU). This pulmonary vascular phenotype is characterized by rather mild to moderate impairment of lung function or lung parenchymal destruction but with severe pulmonary vascular disease or right heart strain. Currently, there are no specific PH medications approved for group 3. However, the use of specific PH medications for the pulmonary vascular phenotype is being discussed in studies or on a case-by-case basis, while in patients with a PVR below 5 WU treatment focuses on the underlying disease.