Pulmonary Stenosis
When the valve to the lungs is narrowed — what it means, how we detect it, and how it is treated.
What Is It
Understanding Pulmonary Stenosis
The pulmonary valve sits between the right ventricle and the pulmonary artery — the vessel that carries blood from the heart to the lungs. In pulmonary stenosis (PS), this valve is abnormally narrowed (stenotic), forcing the right ventricle to work harder to push blood through the tight opening.
PS is the second most common right-sided congenital heart defect, accounting for 8–10% of all CHD. It exists on a spectrum from trivial narrowing requiring no treatment to critical PS in newborns that requires urgent intervention.
Types of Pulmonary Stenosis
| Type | Location | Frequency | Notes |
|---|---|---|---|
| Valvar PS | At the pulmonary valve itself | ~90% | Dome-shaped, fused leaflets; most amenable to balloon dilation |
| Subvalvar (Infundibular) | Below the valve in the right ventricle | ~5% | Often seen with VSD (as in Tetralogy of Fallot) |
| Supravalvar | Above the valve in the pulmonary artery | ~5% | Associated with Noonan syndrome, Williams syndrome, rubella |
| Peripheral | Branch pulmonary arteries | Rare | Bilateral narrowings; may need stent placement |
Severity Classification
Severity is measured by the pressure gradient across the pulmonary valve on echocardiography — the higher the gradient, the tighter the valve and the harder the right ventricle must work.
| Severity | Peak Gradient | Symptoms | Management |
|---|---|---|---|
| Mild | <36 mmHg | None — usually found incidentally | Observe; echo every 3–5 years |
| Moderate | 36–64 mmHg | Possible exertional breathlessness | Monitor closely; consider intervention if symptoms develop |
| Severe | >64 mmHg | Breathlessness, fatigue, right heart strain | Balloon pulmonary valvuloplasty (BPV) |
| Critical (Neonatal) | Very high / right heart failure | Cyanosis, shock in the newborn | Urgent BPV or surgical valvotomy; prostaglandin to maintain PDA |
Signs, Symptoms & the Classic Murmur
Most children with mild PS are completely asymptomatic — the condition is discovered only when a doctor hears a murmur during a routine check. With more severe stenosis, children may tire easily during exercise, appear breathless, or — rarely — have a blue tinge around the lips from low oxygen in the blood.
The classic murmur of PS: A crescendo-decrescendo (ejection systolic) murmur heard best at the upper left sternal border (pulmonary area), often preceded by a click — the “ejection click” caused by the dome-shaped valve snapping open. The click is softer on inspiration. Louder and longer murmurs suggest more severe stenosis.
Diagnosis
Echocardiography is the cornerstone of diagnosis. It defines the valve morphology, measures the gradient across the valve, assesses right ventricular size and function, and looks for associated defects. Most children with PS need nothing more than a good echo.
Cardiac catheterisation was historically used for diagnosis but is now reserved primarily for treatment (balloon valvuloplasty).
Treatment: Balloon Pulmonary Valvuloplasty (BPV)
BPV is the treatment of choice for moderate-to-severe valvar PS. A thin catheter is passed through the groin vein, guided to the heart, and a balloon is inflated across the narrowed valve — splitting the fused leaflets and dramatically widening the opening.
Success rates exceed 95% in appropriately selected patients. Most children go home the next day. Some degree of pulmonary regurgitation (the valve not closing perfectly) is a common after-effect and is usually well tolerated, though severe regurgitation may require valve replacement years later.
Surgery is reserved for cases where balloon dilation fails, for infundibular (subvalvar) PS, or for severely dysplastic valves (as in Noonan syndrome) where the thickened leaflets do not respond to ballooning.
No — mild PS (gradient <36 mmHg) in an asymptomatic child is managed with periodic echocardiographic monitoring, typically every three to five years. The vast majority of mild cases never progress to the point requiring intervention. Your child can participate in all normal activities unless a cardiologist specifically advises otherwise.
No. Balloon valvuloplasty (BPV) is a catheter-based procedure performed through a small tube inserted into the groin vein — no surgical incision is made and no general anaesthesia is usually needed for older children. It is much less invasive than open-heart surgery. The procedure typically takes 60–90 minutes and most children go home the following day.
Mild PS is usually stable and may even improve as the child grows. However, moderate and severe PS can worsen over time, and regular echocardiographic follow-up is important to catch any progression before symptoms develop. This is why your cardiologist schedules regular review appointments even when your child seems perfectly well.
Yes — though infrequent. Even after successful treatment, a small number of patients develop significant pulmonary regurgitation (a leaky valve) years later that may eventually require a replacement pulmonary valve. Annual or biennial echocardiograms are usually recommended to monitor valve function long-term. The great majority of children live completely normal lives.
Children with mild PS can participate in all sports without restriction. Children with moderate or severe untreated PS should have an activity assessment by their cardiologist before engaging in competitive or strenuous sport. After successful BPV with a good result, most children are cleared for all activities within a few weeks.
Key Takeaways
- Pulmonary stenosis is a narrowing of the valve between the right ventricle and the lungs — the most common right-sided CHD after VSD.
- Severity ranges from trivial (observation only) to critical neonatal PS (medical emergency).
- The classic finding is an ejection systolic murmur at the upper left sternal border with an ejection click.
- Balloon pulmonary valvuloplasty (BPV) is the treatment of choice with >95% success rates.
- Most children with mild PS need only periodic monitoring and live completely normal lives.
- Noonan syndrome is the most important associated condition — dysplastic valves respond poorly to ballooning and may need surgery.
Sources
Allen HD et al. Moss and Adams’ Heart Disease in Infants, Children, and Adolescents, 10th Ed. Wolters Kluwer, 2021. Chapter on Pulmonary Stenosis.
Rudolph AM. Congenital Diseases of the Heart, 3rd Ed. Wiley-Blackwell, 2009.
Educational purposes only. Not a substitute for professional medical advice.
