Interpretation:recommendations of the 6st World Symposium on Pulmonary Hypertension（Ⅱ）——haemodynamic definitions and updated clinical classification of pulmonary hypertension / 中国实用内科杂志

Pulmonary hypertension(PH)has been defined as mean pulmonary arterial pressure(mPAP）≥25 mmHg at rest,measured by right heart catheterisation. The 6 th WSPH suggested a new pressure level to define an abnormal elevation as the mPAP>20 mmHg and the need for PVR≥3 WU to define the presence of pre-capillary PH. Regarding clinical classification,the main changes were the inclusion in group 1 of a subgroup“pulmonary arterial hypertension(PAH)long-term responders to calcium channel blockers”and a subgroup“PAH with overt features of venous/capillaries involvement“.