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Key Features

Essentials of Diagnosis

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

  • Dyspnea, chest pain, exertional syncope

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

  • Enlarged central pulmonary arteries on chest radiograph

  • Electrocardiographic 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

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

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

General Considerations

  • The normal pulmonary circulation has low pressure and resistance, but high flow

  • Normal PA systolic pressure at rest is 15 to 30 mm Hg, with a mean pressure between 10 and 18 mm Hg

  • In PH, there is an increase in pulmonary vascular resistance which leads to an increase in PA systolic pressure > 30 mm Hg or mean PA pressure > 25 mm Hg

  • PH is self-perpetuating, inducing changes in pulmonary vessels that further narrow the vascular bed, increasing pressure

  • The World Health Organization classification of PH includes the following 5 groups:

    • Group 1 PH is PA hypertension from idiopathic (formerly primary) PA hypertension, heritable PA hypertension, HIV infection, portal hypertension, drugs and toxins, connective tissue disorders, congenital heart disease, schistosomiasis, primary veno-occlusive disease, and pulmonary capillary hemangiomatosis

    • Group 2 PH is pulmonary venous hypertension secondary to left heart disease, including left ventricular (LV) systolic or diastolic dysfunction, and valvular heart disease

    • Group 3 PH is PH secondary to lung disease or hypoxemia, caused by advanced obstructive and restrictive lung disease including chronic obstructive pulmonary disease, interstitial lung disease, pulmonary fibrosis, bronchiectasis, sleep-disordered breathing, alveolar hypoventilation syndromes, and high altitude exposure

    • Group 4 PH is PH secondary to chronic thromboembolism

    • Group 5 PH is PA hypertension secondary to hematologic disorders (eg, chronic hemolytic 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 disease) and miscellaneous causes (tumor embolization, external compression of the pulmonary vasculature, end-stage renal disease on dialysis)

  • Clinical severity of PH is classified according to the New York Heart Association classification

    • Class I: PH without limitation of physical activity. No dyspnea, fatigue, chest pain or near syncope with exertion

    • Class II: PH resulting in slight limitation of physical activity. No symptoms at rest but ordinary physical activity causes dyspnea, fatigue, chest pain or near syncope

    • Class III: PH resulting in marked limitation of physical activity. No symptoms at rest but less than ordinary activity causes dyspnea, fatigue, chest pain or near syncope

    • Class IV: PH with inability to perform any physical activity without symptoms. Evidence of right heart failure. Dyspnea and fatigue at rest and worsening of symptoms with any activity

Clinical Findings

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