What are Primary and Secondary Pulmonary Hypertension?

In the conventional classification, Pulmonary Hypertension, which is also called Pulmonary Arterial Hypertension, is divided into two main categories; 1) Primary Pulmonary Hypertension (PPH) (not caused by any other disease or condition); and 2) Secondary Pulmonary Hypertension (caused by another underlying condition). Secondary Pulmonary Hypertension is much more common than primary pulmonary hypertension.

A newer classification of this condition is based on the main underlying cause of pulmonary hypertension. This system classifies the condition based on whether it is due to:

  • left sided heart disease

  • lung disease

  • blood clots

  • constriction of arteries due to any reasons (including Primary Pulmonary Hypertension (PPH)), and

  • obstruction from outside of blood vessel (for example from diseases of the chest wall compressing the blood vessels).