Pulmonary valve stenosis !

The valve between the right ventricle and the lung artery is narrow, so the heart works harder. Usually present at birth and treated with a balloon.

Updated 2026-11-01

Structures involved

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Why it happens

What it is

Pulmonary valve stenosis is narrowing of the pulmonary valve that obstructs flow from the right ventricle to the pulmonary trunk. It is almost always congenital: most often a thin, dome-shaped valve with fused commissures, less often a thick, dysplastic valve. Obstruction can also lie below the valve (subvalvular, as in tetralogy of Fallot) or above it (supravalvular or branch pulmonary artery stenosis).

Who gets it

Isolated pulmonary valve stenosis accounts for roughly 8–10% of congenital heart disease and is often found as a murmur in an otherwise well child. Acquired forms are rare (carcinoid heart disease, rheumatic disease). Many mild cases are first detected at routine child or school check-ups.

Causes

Congenital fusion of the valve commissures (dome-shaped valve)
Dysplastic, thickened valve, typical of Noonan syndrome
Part of complex defects such as tetralogy of Fallot
Congenital rubella (mainly peripheral pulmonary artery stenosis) and Williams or Alagille syndrome (supravalvular and branch stenosis)
Acquired: carcinoid heart disease, rarely rheumatic disease or external compression

Risk factors

Noonan syndrome and other RASopathies
Maternal rubella in pregnancy
Family history of congenital heart disease

Pathophysiology

The narrowed valve creates a pressure gradient between the right ventricle and the pulmonary trunk. The right ventricle compensates by concentric hypertrophy, and jet flow causes post-stenotic dilation of the pulmonary trunk. Mild stenosis rarely progresses, while severe stenosis eventually reduces right ventricular compliance and output, raises right atrial pressure and may open a patent foramen ovale with right-to-left shunting and cyanosis. In critical neonatal stenosis, lung blood flow depends on the ductus arteriosus.

Classification

By level: valvular (most common), subvalvular, supravalvular, branch pulmonary artery stenosis
By valve type: dome-shaped (thin, fused commissures) vs dysplastic
By peak Doppler gradient: mild, moderate, severe
Critical pulmonary stenosis of the newborn (ductus-dependent pulmonary blood flow)

Symptoms and signs

Most mild and moderate cases are asymptomatic and found because of a murmur
Exertional dyspnoea and fatigue in severe stenosis
Exertional chest pain or syncope (fixed right ventricular output)
Right-heart failure signs (oedema, hepatomegaly) in long-standing severe disease
Cyanosis and poor feeding in critical neonatal stenosis

Diagnosis

Clinical: Crescendo-decrescendo systolic ejection murmur at the left upper sternal border, preceded by an ejection click that softens with inspiration (the only right-sided sound that does so); widely split S2 with a soft P2; right ventricular heave in severe cases. Look for features of Noonan syndrome (short stature, webbed neck, hypertelorism).
Tests: ECG: normal when mild; right axis deviation and right ventricular hypertrophy when severe. Pulse oximetry in newborns.
Imaging: Echocardiography confirms the level and morphology of obstruction and measures the peak gradient, right ventricular size and function and any atrial shunt. Chest X-ray may show a prominent pulmonary trunk (post-stenotic dilation) with normal or reduced lung markings. Cardiac MRI or CT for branch pulmonary artery stenosis.

Differential diagnosis

Atrial septal defect (flow murmur, fixed split S2)
Innocent pulmonary flow murmur in children
Tetralogy of Fallot
Ventricular septal defect
Aortic stenosis (murmur radiates to the carotids)

Goal of treatment

Relieve significant obstruction early, before right ventricular hypertrophy and failure develop, and keep pulmonary blood flow adequate in critical neonatal disease.

Treatment

Acute: Critical neonatal stenosis: prostaglandin E1 infusion to keep the ductus arteriosus open until the valve is opened.
Procedure: Percutaneous balloon pulmonary valvuloplasty is the first-line treatment for moderate to severe valvular stenosis with a dome-shaped valve.
Surgical: Surgical valvotomy, partial valvectomy or valve replacement for dysplastic valves, subvalvular or supravalvular obstruction, or failed balloon dilation.
Follow-up: Mild stenosis: periodic clinical review and echocardiography; after intervention, follow-up for pulmonary regurgitation and restenosis. Nursing after catheterisation: puncture site, distal pulses and rhythm monitoring.

Complications

Right ventricular hypertrophy and failure
Pulmonary regurgitation after valvuloplasty or surgery
Arrhythmias and, rarely, sudden death in severe disease
Infective endocarditis (uncommon)
Right-to-left shunt through a patent foramen ovale with cyanosis

Prognosis

Mild stenosis has an excellent outlook and seldom progresses. After balloon valvuloplasty long-term results are very good; some patients later need treatment of pulmonary regurgitation.

Prevention

Rubella vaccination before pregnancy
Prenatal ultrasound and newborn pulse oximetry screening for critical disease

Test yourself

Think of the answer, then tap the question to see it.

Which genetic syndrome is classically associated with a dysplastic pulmonary valve?

Noonan syndrome.

How does the pulmonary ejection click change with inspiration?

It becomes softer, unlike other right-sided sounds.

What is first-line treatment for a dome-shaped stenotic pulmonary valve?

Percutaneous balloon valvuloplasty.

What chest X-ray finding results from jet flow through the valve?

Post-stenotic dilation of the pulmonary trunk.

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Educational information, not medical advice. For any symptom, see a health professional.

Sources: Pulmonic valve stenosis (MedlinePlus, US National Library of Medicine, 2026).

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Representative model, for educational purposes only.

Pulmonary anterior cusp highlighted on the Durgical 3D model