Pulmonary hypertension classifications

, Richard Channick, M.D.; Assistant Editor(s)-in-Chief: Ralph Matar, Lisa Prior, Ann Slater, R.N.

Dana Point clinical classification
Updated Clinical Classification of Pulmonary Hypertension(Dana Point, 2008)

'''1'. Pulmonary veno-occlusive disease (PVOD) and/or pulmonary capillary hemangiomatosis (PCH)'''
 * 1. Pulmonary arterial hypertension (PAH)
 * 1.1. Idiopathic PAH
 * 1.2. Heritable
 * 1.2.1. BMPR2
 * 1.2.2. ALK1, endoglin (with or without hereditary hemorrhagic telangiectasia)
 * 1.2.3. Unknown
 * 1.3. Drug- and toxin-induced
 * 1.4. Associated with
 * 1.4.1. Connective tissue diseases
 * 1.4.2. HIV infection
 * 1.4.3. Portal hypertension
 * 1.4.4. Congenital heart diseases
 * 1.4.5. Schistosomiasis
 * 1.4.6. Chronic hemolytic anemia
 * 1.5 Persistent pulmonary hypertension of the newborn
 * 2. Pulmonary hypertension owing to left heart disease
 * 2.1. Systolic dysfunction
 * 2.2. Diastolic dysfunction
 * 2.3. Valvular disease
 * 3. Pulmonary hypertension owing to lung diseases and/or hypoxia
 * 3.1. Chronic obstructive pulmonary disease
 * 3.2. Interstitial lung disease
 * 3.3. Other pulmonary diseases with mixed restrictive and obstructive pattern
 * 3.4. Sleep-disordered breathing
 * 3.5. Alveolar hypoventilation disorders
 * 3.6. Chronic exposure to high altitude
 * 3.7. Developmental abnormalities
 * 4. Chronic thromboembolic pulmonary hypertension (CTEPH)
 * 5. Pulmonary hypertension with unclear multifactorial mechanisms
 * 5.1. Hematologic disorders: myeloproliferative disorders, splenectomy
 * 5.2. Systemic disorders: sarcoidosis, pulmonary Langerhans cell histiocytosis: lymphangioleiomyomatosis, neurofibromatosis, vasculitis
 * 5.3. Metabolic disorders: glycogen storage disease, Gaucher disease, thyroid disorders
 * 5.4. Others: tumoral obstruction, fibrosing mediastinitis, chronic renal failure on dialysis

The Venice 2003 Revised Classification system
In 2003, the 3rd World Symposium on Pulmonary Arterial Hypertension was convened in Venice to modify the classification based on the new understanding of disease mechanisms. The revised system developed by this group provides the current framework for understanding pulmonary hypertension.

The system includes several improvements over the former 1998 Evian Classification system. Risk factor descriptions were updated, and the classification of congenital systemic-to pulmonary shunts was revised. A new classification of genetic factors in PH was recommended, but not implemented because available data were judged to be inadequate.

The Venice 2003 Revised Classification system can be summarized as follows:
 * WHO Group I - Pulmonary arterial hypertension (PAH)
 * WHO Group II - Pulmonary hypertension associated with left heart disease
 * WHO Group III - Pulmonary hypertension associated with lung diseases and/or hypoxemia
 * WHO Group IV - Pulmonary hypertension due to chronic thrombotic and/or embolic disease
 * WHO Group V - Miscellaneous

Venice Clinical Classification of Pulmonary Hypertension (2003) Sarcoidosis, histiocytosis X, lymphangiomatosis, compression of pulmonary vessels (adenopathy, tumor, fibrosing mediastinitis
 * 1. Pulmonary arterial hypertension (PAH)
 * 1.1. Idiopathic (IPAH)
 * 1.2. Familial (FPAH)
 * 1.3. Associated with (APAH)
 * 1.3.1. Collagen vascular disease
 * 1.3.2. Congenital systemic-to-pulmonary shunts
 * 1.3.3. Portal hypertension
 * 1.3.4. HIV infection
 * 1.3.5. Drugs and toxins
 * 1.3.6. Other (thyroid disorders, glycogen storage disease, Gaucher disease, hereditary hemorrhagic telangiectasia, hemoglobinopathies, myeloproliferative disorders, splenectomy)
 * 1.4. Associated with significant venous or capillary involvement
 * 1.4.1. Pulmonary veno-occlusive disease (PVOD)
 * 1.4.2. Pulmonary capillary hemangiomatosis (PCH)
 * 1.5. Persistent pulmonary hypertension of the newborn
 * 2. Pulmonary hypertension with left heart disease
 * 2.1. Left-sided atrial or ventricular heart disease
 * 2.2. Left-sided valvular heart disease
 * 3. Pulmonary hypertension associated with lung diseases and/or hypoxemia
 * 3.1. Chronic obstructive pulmonary disease
 * 3.2. Interstitial lung disease
 * 3.3. Sleep-disordered breathing
 * 3.4. Alveolar hypoventilation disorders
 * 3.5. Chronic exposure to high altitude
 * 3.6. Developmental abnormalities
 * 4. Pulmonary hypertension owing to chronic thrombotic and/or embolic disease
 * 4.1. Thromboembolic obstruction of proximal pulmonary arteries
 * 4.2. Thromboembolic obstruction of distal pulmonary arteries
 * 4.3. Nonthrombotic pulmonary embolism (tumor, parasites, foreign material)
 * 5. Miscellaneous

Previous terminology
The terms primary and secondary pulmonary hypertension (PPH and SPH) were formerly used to classify the disease. This led to the assumption that only the primary disease should be treated, and the secondary variety should be ignored in favor of treating only the underlying illness. In fact all forms of pulmonary arterial hypertension are treatable. Unfortunately, this classification system still persists in the minds of many physicians, and probably leads to many patients with being denied treatment. This approach to pulmonary arterial hypertension may also contribute to underdiagnosis. It is estimated that there are about 100,000 patients with PAH in the US, but only 15-20,000 have been diagnosed. Many others have been misdiagnosed as COPD, asthma, or congestive heart failure.

The term primary pulmonary hypertension (PPH) has now been replaced with idiopathic pulmonary arterial hypertension (IPAH) in much of the medical literature. However, some physicians continue to use the older classification inappropriately.