The who classification of pulmonary hypertension: A case-based imaging compendium

John J. Ryan, Thenappan Thenappan, Nancy Luo, Thanh Ha, Amit R. Patel, Stuart Rich, Stephen L. Archer

Research output: Contribution to journalArticlepeer-review

44 Scopus citations


Pulmonary hypertension (PH) is defined as a resting mean pulmonary artery pressure greater than 25 mmHg. The World Health Organization (WHO) classifies PH into five categories. The WHO nomenclature assumes shared histology and pathophysiology within categories and implies category-specific treatment. Imaging of the heart and pulmonary vasculature is critical to assigning a patient’s PH syndrome to the correct WHO category and is also important in predicting outcomes. Imaging studies often reveal that the etiology of PH in a patient reflects contributions from several categories. Overlap between Categories 2 and 3 (left heart disease and lung disease) is particularly common, reflecting shared risk factors. Correct classification of PH patients requires the combination of standard imaging (chest roentgenograms, ventilation-perfusion scans, echocardiography, and the 12-lead electrocardiogram) and advanced imaging (computed tomography, cardiac magnetic resonance imaging, and positron emission tomography). Despite the value of imaging, cardiac catheterization remains the gold standard for quantification of hemodynamics and is required before initiation of PH-specific therapy. These cases illustrate the use of imaging in classifying patients into WHO PH Categories 1-5.

Original languageEnglish (US)
Pages (from-to)107-121
Number of pages15
JournalPulmonary Circulation
Issue number1
StatePublished - Jan 2012

Bibliographical note

Publisher Copyright:
© 2012, Taylor and Francis Inc. All rights reserved.


  • Eisenmenger’s syndrome
  • Late gadolinium enhancement
  • Pulmonary artery acceleration time
  • Pulmonary capillary hemangiomatosis
  • Pulmonary veno-occlusive disease
  • Right ventricular hypertrophy


Dive into the research topics of 'The who classification of pulmonary hypertension: A case-based imaging compendium'. Together they form a unique fingerprint.

Cite this