Classifying severity of Pulmonary Arterial Hypertension

Once Pulmonary arterial hypertension (PAH) has been diagnosed, it is usually classified according to a system adapted for Pulmonary Arterial Hypertension (PAH) by the World Health Organization (WHO).

Functional class is one way of describing the severity of Pulmonary Arterial Hypertension (PAH) and reflects the impact the condition has on a patient's life in terms of physical activity and symptoms. There are four classes, with class I being the least severe and class IV being the most advanced.¹ For example, patients with Class I Pulmonary Arterial Hypertension (PAH) are not limited in terms of physical activity, whereas those with class IV cannot carry out any physical activity without symptoms and may even experience symptoms when they are at rest.

References
1. Rich S (Ed). World Health Organisation: primary pulmonary hypertension - executive summary, World Symposium, Primary Pulmonary Hypertension 1998