Definition and classification of pulmonary hypertension

Abstract

Pulmonary hypertension is defined as an increase of mean pulmonary arterial pressure ≤25 mmHg at rest as assessed by right heart catheterization. According to different combinations of values of pulmonary wedge pressure, pulmonary vascular resistance and cardiac output, a hemodynamic classification of pulmonary hypertension has been proposed. Of major importance is the pulmonary wedge pressure which allows to distinguish pre-capillary (pulmonary wedge pressure 15 mmHg) and post-capillary (pulmonary wedge pressure <15 mmHg) pulmonary hypertension. Precapillary pulmonary hypertension includes the clinical groups 1 (pulmonary arterial hypertension), 3 (pulmonary hypertension due to lung diseases and/or hypoxia), 4 (chronic thrombo-embolic pulmonary hypertension) and 5 (pulmonary hypertension with unclear and/ormultifactorial mechanisms). Post-capillary pulmonary hypertension corresponds to the clinical group 2 (pulmonary hypertension due to left heart diseases). © Springer-Verlag Berlin Heidelberg 2013.