Pulmonary Valve Stenosis (PVS)

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Pulmonary Valve Stenosis (PVS)

Description

Pulmonary valve stenosis is a valvular heart disease in which narrowing of the pulmonary valve impedes blood flow from the right ventricle (RV) into the pulmonary artery during systole. The obstruction creates resistance against which the RV must pump, resulting in pressure overload and compensatory hypertrophy of the RV wall.


Epidemiology

  • Accounts for about 10% of all congenital heart defects (CHDs), making it one of the more common CHDs.

  • Usually congenital:

    • The valve leaflets may be dysplastic (thickened, fused, or dome-shaped).

    • Rarely acquired causes: rheumatic heart disease, carcinoid syndrome, or post-surgical changes.

  • Genetic associations: Strongly associated with Noonan syndrome, where dysplastic pulmonary valves are part of the phenotype.

Pathophysiology

  1. Valve narrowing → obstruction of RV outflow during systole.

  2. Increased RV pressure is required to overcome this obstruction.

  3. Chronic pressure overload → right ventricular hypertrophy (RVH).

  4. Over time:

    • If severe, RV function declines → right-sided heart failure.

    • Hypertrophy can also cause arrhythmias.

    • Post-stenotic dilation of the pulmonary artery may occur due to high-velocity jet flow striking the vessel wall.

Clinical Features

The severity of stenosis determines presentation:

  • Mild PVS: often asymptomatic, discovered incidentally on auscultation.

  • Moderate-to-severe PVS:

    • Dyspnea on exertion.

    • Fatigue, reduced exercise tolerance.

    • Signs of right-sided heart failure in advanced cases (hepatomegaly, peripheral edema, ascites).

Characteristic auscultatory findings:

  • Systolic ejection murmur: crescendo–decrescendo murmur best heard at the second left intercostal space, parasternal.

  • Wide splitting of S2: caused by prolonged RV ejection.

  • Systolic thrill may be palpable in the left upper sternal border in severe cases.

Diagnostics

  • Echocardiography (gold standard):

    • Direct visualization of the pulmonary valve.

    • Measures pressure gradient across the valve (severity grading).

    • Detects post-stenotic dilation of the pulmonary artery.


  • Chest X-ray:

    • May show enlarged pulmonary artery segment (post-stenotic dilatation).

    • Right ventricular enlargement in advanced disease.


  • ECG:

    • Evidence of RVH (tall R waves in V1, right axis deviation).

    • Right atrial enlargement may also be seen.


Treatment

Critical pulmonary valve stenosis in neonates

  • These infants rely on a patent ductus arteriosus (PDA) to maintain pulmonary blood flow.

  • Immediate management: prostaglandin E₁ infusion to keep the PDA open until definitive intervention.

  • Without this, profound hypoxemia and circulatory collapse can occur.

Noncritical pulmonary valve stenosis

  • Indications for intervention:

    • Symptomatic patients (heart failure, exercise intolerance).

    • Moderate to severe gradient (>40–50 mmHg peak gradient).

  • Preferred procedure: balloon valvuloplasty (catheter-based, dilates the valve).

  • Surgical options:

    • Pulmonary valvotomy or valve replacement (in cases of severely dysplastic valves or failed balloon procedure).

✅ Key clinical pearls:

  • PVS is often well tolerated if mild and may go undetected until adulthood.

  • Severe forms in neonates are life-threatening and require ductal patency.

  • Balloon valvuloplasty has revolutionized management, reducing the need for open surgery in most cases.

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