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).