What are the WHO clinical classifications of pulmonary hypertension?

Updated: Apr 25, 2018
  • Author: Kristin E Schwab, MD; Chief Editor: Zab Mosenifar, MD, FACP, FCCP  more...
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Answer

The World Health Organization (WHO) has divided pulmonary hypertension into five groups on the basis of similarities in pathophysiology, clinical presentation, and therapeutic options. [1] These groups include the following:

  • Group 1 - Pulmonary arterial hypertension (PAH)
  • Group 2 - Pulmonary hypertension due to left-sided heart disease
  • Group 3 - Pulmonary hypertension due to lung diseases and/or hypoxia
  • Group 4 - Chronic thromboembolic pulmonary hypertension (CTEPH)
  • Group 5 - Pulmonary hypertension with unclear or multifactorial etiologies, including hematologic disorders (eg, myeloproliferative disorders), systemic disorders (eg, sarcoidosis, pulmonary Langerhans cell histiocytosis, lymphangioleiomyomatosis, neurofibromatosis, vasculitis), metabolic disorders (eg, glycogen storage disease, Gaucher disease, thyroid disorders), and miscellaneous conditions (eg, tumor obstruction, mediastinal fibrosis, chronic renal failure on dialysis)

Recognition of fetal causes and developmental abnormalities has also led to a pediatric-specific classification. [2]

This review focuses on group 1 pulmonary hypertension, which is also referred to as pulmonary arterial hypertension.

Note the gross pathology images of PAH below.

Gross pathology on patient who died of severe pulm Gross pathology on patient who died of severe pulmonary arterial hypertension secondary to persistent patent ductus arteriosus.
Close-up view of gross pathology on patient who di Close-up view of gross pathology on patient who died of severe arterial pulmonary hypertension secondary to persistent patent ductus arteriosus.

For patient education resources, see the Lung and Airway Center.


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