Learn about pulmonary hypertension (PH), a condition that causes high blood pressure in the pulmonary arteries. Find out the causes, types, symptoms, diagnosis and treatment options for PH. Pulmonary hypertension encompasses a diverse group of conditions characterized by high pulmonary pressures. The World Health Organization classifies pulmonary hypertension into 5 clinical groups based on pathophysiology, hemodynamic characteristics, clinical features, and management (see Table 1. Clinical Classification of Pulmonary Hypertension ).[1] Pulmonary hypertension is the most serious and common complication of pulmonary vascular disease, which encompasses any condition or disease that affects the lungs' blood vessels. Pulmonary hypertension (PH) is a form of high blood pressure affecting the pulmonary artery, the vessel that carries deoxygenated blood into the lungs to pick up oxygen. It can lead to difficulty breathing and a reduction in usually performed activities, taking a physical and emotional toll on an ...