Professional Statements and Societal Positions Guidelines
The World Health Organization (WHO) classifies pulmonary hypertension (PH) into five (5) categories based on the disease etiology. These diagnostic classifications include:
- Group I pulmonary arterial hypertension
- Group II pulmonary hypertension with left heart disease
- Group III pulmonary hypertension associated with lung disease and/or hypoxemia
- Group IV pulmonary hypertension due to chronic thromboembolic disease
- Group V pulmonary hypertension with unclear multifactorial mechanisms.
Functional assessment of patients with Pulmonary Arterial Hypertension (PAH) is based on the severity of the disease, which is classified according to the clinical symptoms on a scale of I to IV. Categorization is based on the WHO classification system, which has been modified for PAH from the New York Heart Association (NYHA) functional classifications of patients with cardiac disease.
WHO Functional Classification for Pulmonary Arterial Hypertension (PAH):
Class I | No limitation of clinical activity; ordinary physical activity does not cause dyspnea or fatigue. |
Class II | Slight limitation in physical activity; ordinary physical activity produces dyspnea, fatigue, chest pain, or near-syncope; no symptoms at rest. |
Class III | Marked limitation of physical activity; less than ordinary physical activity produces dyspnea, fatigue, chest pain, or near-syncope; no symptoms at rest. |
Class IV | Unable to perform any physical activity without symptoms; dyspnea and/or fatigue present at rest; discomfort increased by any physical activity. |
New York Heart Association (NYHA) Functional Classifications:
Class I | Patients with no limitation of activities; they suffer no symptoms from ordinary activities |
Class II | Patients with slight, mild limitation of activity; they are comfortable with rest or mild exertion. |
Class III | Patients with marked limitation of activity; they are comfortable only at rest. |
Class IV | Patients who should be at complete rest, confined to bed or chair; any physical activity brings on discomfort and symptoms occur at rest. |
American College of Chest Physicians
In 2014, the American College of Chest Physicians published guidelines on pharmacologic therapy for PAH in adults. Relevant recommendations include:
- For patients with PAH who are treatment-naive, have WHO functional class II or class III symptoms and have failed or are not candidates for CCB therapy, monotherapy with an approved medication is recommended (e.g., endothelin receptor antagonist, phosphodiesterase type 5 inhibitor, riociguat).
- For patients with PAH in WHO functional class III who have evidence of disease progression or poor clinical prognosis despite treatment with 1 or 2 classes of oral agents, consideration of the addition of a parenteral or inhaled prostanoid is recommended.
For patients with PAH who are treatment-naive and have WHO functional class IV symptoms, initial monotherapy with a parental prostanoid agent is recommended. If patients are unable or unwilling to manage parenteral therapy, combination treatment with an inhaled prostanoid and an endothelin receptor antagonist is recommended.
