Pulmonary Valve Stenosis

Key Features

Essentials of Diagnosis

• No symptoms in mild or moderate stenosis

• Cyanosis and a high incidence of right-sided heart failure (HF) in ductal-dependent lesions

• Right ventricular (RV) lift with systolic ejection click heard at the third left intercostal space

• S₂ widely split with soft to inaudible P₂; grade I–VI/VI systolic ejection murmur, maximal at the pulmonary area

• Dilated pulmonary artery on chest radiograph

General Considerations

• Accounts for 10% of all congenital heart disease

• The pulmonary valve annulus is usually small with moderate to marked poststenotic dilation of the main pulmonary artery

• Obstruction to blood flow across the pulmonary valve causes an increase in RV pressure

• Pressures greater than systemic are potentially life-threatening and are associated with critical obstruction

• Because of the increased RV strain, severe right ventricular hypertrophy (RVH) and eventual RV failure can occur

• When obstruction is severe and the ventricular septum is intact, a right-to-left shunt often occurs at the atrial level through a patent foramen ovale (PFO)

• In neonates with severe obstruction and minimal antegrade pulmonary blood flow (critical PS),

  • Left-to-right flow through the ductus is essential

  • Prostaglandin is a necessary intervention at the time of birth

  • Infants are cyanotic at presentation

Clinical Findings

• Mild to moderate obstruction

  • Patients are

    • Acyanotic and asymptomatic

    • Well developed and well nourished

    • Not prone to pulmonary infections

  • Pulses are normal

  • Precordium may be prominent, often with palpable RV heave

  • A systolic thrill is often present in the pulmonary area

  • Prominent ejection click of pulmonary origin

    • Heard at the third left intercostal space

    • Varies with respiration, being more prominent during expiration than inspiration

• Severe obstruction

  • Cyanosis may develop early

  • Click tends to merge with S1

• S2 varies with the degree of stenosis

  • Normal in mild pulmonic stenosis

  • More widely split and the pulmonary component is softer in moderate pulmonic stenosis

  • Single because the pulmonary component cannot be heard in severe pulmonary stenosis

• Rough systolic ejection murmur

  • Best heard at the second left interspace

  • Radiates well to the back

  • Usually short in severe pulmonary valve obstruction

• No diastolic murmurs are audible

Diagnosis

Imaging

• Radiography

  • Heart size is normal

  • Poststenotic dilation of the main pulmonary artery and the left pulmonary artery often occurs

• Echocardiography

  • Confirms the diagnosis

  • Defines the anatomy

  • Identifies any associated lesions

  • Pulmonary valve has thickened leaflets with reduced valve leaflet excursion

  • Transvalvular pressure gradient can be estimated accurately by Doppler, which

    • Provides an estimate of RV pressure

    • Can assist in determining the appropriate time to intervene

Diagnostic Procedures

• Electrocardiography

  • Usually normal with mild obstruction

  • Right axis deviation occurs in moderate to severe stenosis

  • In severe obstruction

    • RVH with an RV strain pattern (deep inversion of the T wave) occurs in the right precordial leads (V3R, V1, V2)

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