What's idiopathic pulmonary arterial hypertension?
Idiopathic pulmonary arterial hypertension (IPAH) is Group 1 pulmonary hypertension with no identified cause. It is a diagnosis of exclusion, confirmed by right heart catheterization showing raised pulmonary artery pressure and pulmonary vascular resistance after other causes of pulmonary hypertension have been ruled out. By definition it is idiopathic; BMPR2 and related gene mutations belong to the separate heritable form of PAH, not to IPAH.
| Also indexed as | ORPHA:275766, MONDO:0001999 |
|---|---|
| Features mapped | 11 |
| Treatments mapped | 5 |
| Published sources | 11 |
| Last reviewed | 2026-08-04 |
Signs and symptoms
Ankle swelling
Swelling in the lower legs, along with fainting and near-fainting, tends to appear in more advanced pulmonary arterial hypertension rather than at the start.
Pedal edema
Swelling in the feet, along with fainting and near-fainting, tends to appear in more advanced pulmonary arterial hypertension rather than at the start.
Syncope
Fainting, along with near-fainting and leg swelling, tends to appear in more advanced pulmonary arterial hypertension rather than at the start.
Congestive heart failure
As pulmonary arterial hypertension progresses, the steady rise in resistance in the lung arteries strains the right side of the heart and can lead to right heart failure.
Elevated pulmonary artery pressure
Pulmonary arterial hypertension is characterized by raised average pressure in the pulmonary artery, the vessel carrying blood from the heart to the lungs, caused by disease of the small lung arterioles.
Pulmonary arterial hypertension
Pulmonary arterial hypertension leads to a cluster of symptoms that can include shortness of breath, fatigue, fainting, chest discomfort, and swelling in the body's tissues.
Palpitations
Palpitations, an awareness of a rapid or irregular heartbeat, can be an early symptom of pulmonary arterial hypertension as the strained right side of the heart works harder.
Increased pulmonary vascular resistance
Pulmonary arterial hypertension is marked by a progressive rise in the resistance the blood meets in the lung arteries, which over time strains the right side of the heart and can lead to right heart failure.
Right ventricular hypertrophy
The right ventricle thickens (hypertrophies) as it works harder against the high pressure. Effective treatment can reverse some of this remodeling.
Dyspnea
The most common symptom is progressive breathlessness on exertion. Because it overlaps with far more common heart and lung conditions, the diagnosis is often delayed.
Chest pain
Chest pain can occur in pulmonary arterial hypertension, often during exertion, and tends to appear as the disease progresses.
How it is diagnosed
Idiopathic pulmonary arterial hypertension
Diagnosed using: right heart catheterization.
“Definitive diagnosis, however, requires right heart catheterization, preferably at an accredited pulmonary hypertension (PH)…”
Idiopathic pulmonary arterial hypertension
Diagnosed using: transthoracic echocardiography.
“Transthoracic echocardiography is the most helpful initial imaging modality for estimating pulmonary artery pressures and assessing right ventricular structure and function.”
Treatment and management
What the research describes, not a recommendation. Treatment decisions belong with your clinician.
This covers treatments that appear in the published research mapped here. Investigational and experimental therapies are not included, so their absence is a boundary of this map, not a sign they do not exist.
endothelin receptor antagonist
Endothelin receptor antagonists are a standard class of medicine for pulmonary arterial hypertension, often combined with phosphodiesterase-5 inhibitors as initial therapy.
Used to help with: Idiopathic pulmonary arterial hypertension.
“Macitentan is an oral, dual ETA/ETB endothelin receptor antagonist, currently approved in adults for the treatment of pulmonary arterial hypertension…”
phosphodiesterase-5 inhibitors
Phosphodiesterase-5 inhibitors are a standard class of medicine for pulmonary arterial hypertension, often combined with endothelin receptor antagonists as initial therapy.
Used to help with: Idiopathic pulmonary arterial hypertension.
“Phosphodiesterase-5 inhibitors (PDE-5is) are fundamental in pulmonary arterial hypertension (PAH)…”
prostacyclins
Prostacyclin therapies (such as epoprostenol, treprostinil, and the oral agent selexipag) act on the prostacyclin pathway to dilate lung vessels. Parenteral (infused) prostacyclins are reserved for high-risk, severe disease.
Used to help with: Idiopathic pulmonary arterial hypertension.
“Parenteral prostacyclins are recommended for high-risk…”
soluble guanylate cyclase stimulator
Riociguat, a soluble guanylate cyclase stimulator, also works through the nitric-oxide pathway to relax lung vessels. It must not be combined with phosphodiesterase-5 inhibitors because of the risk of dangerously low blood pressure.
Used to help with: Idiopathic pulmonary arterial hypertension.
“Riociguat (a soluble guanylate cyclase…”
sotatercept
Sotatercept is a newer fusion-protein therapy that targets the activin signaling pathway involved in the abnormal vessel growth, addressing a mechanism the older vasodilator drugs do not. It is a recent addition shown to improve exercise capacity and hemodynamics.
Used to help with: Idiopathic pulmonary arterial hypertension.
“…the new fusion protein named…”
What changes how it shows up
The diagnosis is not the whole story. The factors and open questions below are described in the research mapped here as shaping whether, or how strongly, the condition shows up, or as points the field has not yet settled. They are not, on their own, its cause or its cure.
female predominance
Idiopathic pulmonary arterial hypertension occurs more often in women; in a cohort of adults with Group 1 pulmonary arterial hypertension, most participants were female.
Described as modulating: Idiopathic pulmonary arterial hypertension.
“…mostly female…”
acute vasoreactivity
A minority of people with pulmonary arterial hypertension show vasoreactivity, meaning their lung arteries respond to a vasodilator during testing; this response affects which treatments are appropriate.
Described as modulating: Idiopathic pulmonary arterial hypertension.
“104 (19%) were ineligible at baseline, mainly due to non-permitted PAH subtypes (71%) or vasoreactivity…”
How to read the evidence labels
Where this comes from
This guide is built from 11 published source(s). Every claim above links back to one of them. Click any source ID to read the original on PubMed.
Take it further
Printed, source-linked documents built from this condition's graph — ready to bring to an appointment or attach to a coverage request. Every claim carries its published source, the same as this guide.