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For further information, see CMDT Part 9-26: Pulmonary Hypertension

For further information, see CMDT Part 10-53: Pulmonary Hypertension & Pulmonary Heart Disease

Key Features

Essentials of Diagnosis

  • Defined as pulmonary artery (PA) systolic pressure > 30 mm Hg or mean PA pressure > 25 mm Hg

  • Multiple potential etiologies must be considered, including both pulmonary and cardiac

  • Idiopathic (primary) pulmonary hypertension (PH) most frequently occurs in younger women

  • Dyspnea, chest pain, exertional syncope

  • Narrow splitting of second heart sound with loud pulmonary component; findings of right ventricular (RV) hypertrophy and heart failure in advanced disease

  • Enlarged central pulmonary arteries on chest radiograph

  • ECG evidence of RV strain or hypertrophy and right atrial (RA) enlargement

  • Two-dimensional echocardiography with Doppler flow echocardiography is often diagnostic, showing elevated RV systolic pressure; right heart catheterization is confirmatory

General Considerations

  • During the 2019 Sixth World Symposium on Pulmonary Hypertension, the definition of PH was changed

  • PH was defined by a mean PA pressure of 20 mm Hg with a pulmonary vascular resistance (PVR) of ≥ 3 Wood units and then categorized into three groupings:

    • Precapillary PH: Mean pulmonary arterial pressure (PAP) > 20 mm Hg, PVR ≥ 3.0 Wood units, pulmonary capillary wedge pressure (PCWP) ≤ 15 mm Hg

    • Isolated post-capillary PH: Mean PAP > 20 mm Hg, PVR < 3.0 Wood units, PCWP > 15 mm Hg

    • Combined pre- and post PH: Mean PAP > 20 mm Hg, PVR ≥ 3.0 Wood units, PCWP > 15 mm Hg

  • The World Health Organization (WHO)/New York Heart Association (NYHA) functional class classification of PH includes the following 5 groups:

    • Group I (pulmonary arterial hypertension [PAH]) with pulmonary vasculopathy, PH, and elevated PVR in the absence of other diseases of the lungs or heart

    • This group includes

      • Idiopathic (formerly primary) PAH

      • Heritable PAH

      • Drugs and toxins-induced PAH (anorexigenic agents (aminorex fumarate, fenfluramine, dexfenfluramine), rapeseed oil, L-tryptophan, amphetamines and cocaine)

      • PAH associated with HIV infection, portal hypertension, connective tissue disorders (most commonly systemic sclerosis), congenital heart disease (Eisenmenger syndrome), schistosomiasis, sickle cell disease

      • Obstruction of the pulmonary venous circulation (pulmonary veno-occlusive disease and capillary hemangiomatosis)

    • Group II (pulmonary venous hypertension due to left heart disease): Includes

      • Left ventricular (LV) systolic or diastolic dysfunction

      • Valvular heart disease

    • Group III (PH due to lung disease or hypoxemia): Causes include

      • Advanced obstructive and restrictive lung disease including chronic obstructive pulmonary disease (COPD)

      • Interstitial lung disease

      • Pulmonary fibrosis

      • Sleep-disordered breathing

      • Alveolar hypoventilation syndromes

      • High altitude exposure

    • Group IV (PH due to pulmonary arterial obstruction): This group includes

      • Chronic thromboembolic PH (primarily)

      • Other causes of pulmonary arterial obstructions, such as sarcoma, metastatic malignancies, and congenital pulmonary artery stenosis

    • Group V (PH secondary with unclear or multifactorial mechanisms): These patients have PH secondary to

      • Hematologic disorders (eg, chronic hemolytic anemia, sickle cell anemia, myeloproliferative disorders, splenectomy)

      • Systemic disorders (eg, sarcoidosis, vasculitis, pulmonary Langerhans cell histiocytosis, neurofibromatosis type 1)

      • Metabolic disorders (eg, glycogen storage disease, Gaucher disease, thyroid ...

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