Pulmonary Hypertension and Interstitial Disease

Pulmonary hypertension is a haemodynamic state of abnormally raised pressure in the pulmonary arteries that strains the right side of the heart, while interstitial lung diseases are a diverse group of disorders that scar or inflame the lung parenchyma (the interstitium) and impair gas exchange. The two are grouped here because interstitial and other chronic lung diseases are a recognised cause of pulmonary hypertension, and both present respiratory nursing with progressive breathlessness, reduced exercise tolerance, and oxygen needs.

Definition

Pulmonary hypertension is defined by an elevated mean pulmonary arterial pressure measured at right-heart catheterisation, classified into clinical groups by underlying cause (ESC/ERS guidelines; Humbert et al., 2022); interstitial lung diseases are a heterogeneous group of parenchymal disorders classified by clinical, radiological, and pathological features, including the idiopathic interstitial pneumonias (Travis et al., 2013).

Scope

This entry covers pulmonary hypertension and interstitial lung disease as clinical entities within respiratory nursing: their definitions, the mechanisms linking parenchymal and pulmonary-vascular disease, and the society guidelines that frame their diagnosis and classification. It is reference and educational material and does not provide dosing or individualised treatment instructions.

Core questions

• What defines pulmonary hypertension haemodynamically and how is it classified?
• How do interstitial lung diseases impair gas exchange?
• Why are interstitial and chronic lung diseases linked to pulmonary hypertension?
• How do the ESC/ERS and ATS/ERS frameworks structure diagnosis and classification?

Key concepts

• Elevated pulmonary arterial pressure
• Right ventricular strain
• Pulmonary vascular remodelling
• Interstitial (parenchymal) lung disease
• Pulmonary fibrosis
• Idiopathic interstitial pneumonias
• Progressive dyspnoea and reduced exercise tolerance
• Clinical classification groups

Mechanisms

In pulmonary hypertension, narrowing and remodelling of the pulmonary vasculature — or elevated pressures transmitted from left-heart disease, chronic lung disease and hypoxia, or chronic thromboembolism — raise pulmonary arterial pressure and impose a pressure load on the right ventricle, which can progress to right-heart failure (Hassoun, 2021). In interstitial lung disease, inflammation and/or fibrosis thicken and scar the alveolar walls and interstitium, reducing lung compliance and the efficiency of gas exchange; chronic parenchymal disease and the accompanying hypoxia are themselves a recognised cause of pulmonary hypertension, which is why the two conditions are considered together (Travis et al., 2013; Humbert et al., 2022).

Clinical relevance

Patients with pulmonary hypertension or interstitial lung disease present respiratory nursing with progressive breathlessness, fatigue, reduced exercise tolerance, and oxygen requirements, often in the context of complex specialist follow-up. The entry describes these conditions and their guideline context for orientation and education; it is not a basis for prescribing or titrating treatment.

Epidemiology

Pulmonary hypertension and interstitial lung diseases are individually less common than obstructive airway disease but carry high morbidity and, for several forms such as idiopathic pulmonary fibrosis, a poor prognosis; the ESC/ERS pulmonary hypertension guidelines and the ATS/ERS interstitial pneumonia classification summarise how these conditions are categorised and characterised across populations (Humbert et al., 2022; Travis et al., 2013).

Evidence & guidelines

The 2022 ESC/ERS guidelines provide the international framework for defining, classifying, and diagnosing pulmonary hypertension (Humbert et al., 2022). For interstitial lung disease, the ATS/ERS/JRS/ALAT guideline on the diagnosis of idiopathic pulmonary fibrosis (Raghu et al., 2018) and the ATS/ERS multidisciplinary classification of the idiopathic interstitial pneumonias (Travis et al., 2013) are the principal reference documents. These describe diagnosis and classification at a specialist and population level rather than individualised orders.

Seminal works

• humbert-2022-esc-ers-ph
• raghu-2018-ipf
• travis-2013-iip-classification

Frequently asked questions

Why are pulmonary hypertension and interstitial lung disease discussed together?

Chronic interstitial and other lung diseases, along with the hypoxia they cause, are a recognised cause of pulmonary hypertension, so the two frequently coexist and are framed together in respiratory care.

How is pulmonary hypertension confirmed?

It is defined haemodynamically by an elevated mean pulmonary arterial pressure measured at right-heart catheterisation and is then classified by its underlying cause, per the ESC/ERS guidelines.