What is pulmonary arterial hypertension?

Pulmonary arterial hypertension (PAH) is a condition where the blood vessels in the lungs become abnormally narrow and stiff. The heart's right ventricle has to work harder to push blood through, and over time it weakens. Without treatment, PAH is progressive and life-threatening.

Symptoms. Shortness of breath on exertion is the most common early symptom, often dismissed as deconditioning. Fatigue, dizziness on standing, and chest discomfort appear as the disease progresses. Diagnosis usually requires right-heart catheterisation to confirm, which is why specialty referral is essential.

The therapy classes. Four medication classes target different aspects of the abnormal lung-vessel biology. Endothelin receptor antagonists block a vessel-constricting signal. Phosphodiesterase-5 inhibitors enhance a vessel-relaxing signal. Prostacyclin pathway agents directly relax lung vessels. Sotatercept, a newer mechanism, targets an activin signalling pathway involved in vessel stiffness.

Combination therapy. Most PAH patients now receive combination therapy from the start rather than sequential escalation. Triple-class combinations are common in higher-risk patients.

Where care happens. PAH care is typically delivered at specialised centres with experience managing the condition. The combination therapy and monitoring requirements are too complex for routine community pulmonology in most cases.