<prompt> Pulmonary Hypertension is defined as Pulmonary Artery Pressure-15mm Hg18mm Hg20mm Hg25mm Hg  <response>: Ans. is d i.e., 25 mmHg Link; Documenisguidelines-PH-FTpdfo PH has been defined as an increase in mean pulmonary arterial pressure PAP 25 mmHg at rest as assessed by right heart catheterization RHC.DefinitionCharacteristicsClinical groupsPulmonary- hypertension PHo Mean PAP 25mmHgo AllPre-capillary PHo Mean PAP 25mmHgo PWP ISmmHgo CO normal or reducedo Pulmonary arterial hypertensiono PH due to lung diseaseso Chronic thromboembolic PHo PH with under andfar multifactorial mechanismsPost-capillary PHo Mean PAP ISmmHgo PWP ISmmHgo CO normal or reducedo PH due to left heart diseaseNote; High CO can be present in cases of hyperkinetic conditions such as systemic to-pulmonarv shunts only in the pulmonary circulation. Anaemia, Hyperthyroidism, etc.CO cardiac output; PAP pulmonary arterial pressure; PH pulmonary hypertension; PWP pulmonary wedge pressure. 