||What Is It?
Pulmonary Hypertension is high blood pressure in the vessels that carry blood from the heart to the lungs (the pulmonary artery and its branches).
By definition, Pulmonary Hypertension is diagnosed when the blood pressure in the heart to lung circulation exceeds 25 mm Hg at rest or 30 mm Hg with exercise.
Two kinds of Pulmonary Hypertension are recognized: Secondary, in which the cause of the high blood pressure is known; and Primary, in which the cause is unknown. Primary Pulmonary Hypertension (PPH) is a rare condition, affecting females more frequently than males (2.4 to 1), and is likely a genetic defect and can be inherited.
Secondary Pulmonary Hypertension may be caused by congenital blockages of the pulmonary (heart to lung) circulation. Pressure builds in the pulmonary artery (or its branches) or the pulmonary veins, which carry blood from the lungs to the heart, as the blood backs up because of resistance to blood flow.
Secondary Pulmonary Hypertension may also be caused by late or unrepaired congenital heart disease in which a long standing increase in blood flow to the pulmonary arteries eventually results in permanent and progressive stiffening of the pulmonary arteries.
Other factors that may result in Pulmonary Hypertension include chronic lung disease or sleep apnea which results in low oxygen concentration in the blood (chronic hypoxemia).