What are the clinical findings and management strategies for pulmonary stenosis?

Pulmonary Stenosis: Clinical Findings and Management

Pulmonary stenosis is primarily a congenital condition characterized by fusion of valve leaflets, with clinical manifestations and management determined by stenosis severity as measured by right ventricle to pulmonary artery pressure gradients. 1

Clinical Findings

Pathophysiology

• Primarily congenital in origin (rarely acquired)
• Most common form: dome-shaped pulmonary valve with fused leaflets
• Less common: dysplastic valve with thickened, poorly mobile cusps (15-20% of cases) 1
• May occur at different levels:
  • Valvular (most common)
  • Subvalvular/infundibular
  • Supravalvular (main pulmonary trunk or branches) 1

Symptoms

• Mild to moderate stenosis: Usually asymptomatic
• Severe stenosis: Dyspnea, fatigue, reduced exercise capacity
• Advanced cases: Exertional syncope, light-headedness (especially with dehydration or pregnancy)
• Long-standing untreated cases: Tricuspid regurgitation and right ventricular failure 1

Physical Examination

• Harsh systolic murmur across the obstruction
• Wide splitting of the second heart sound
• In peripheral pulmonary stenosis: Systolic murmurs heard over lung fields 1
• Pulmonary vascular bruits (may increase with inspiration) in peripheral stenosis 1

Complications

• Right ventricular hypertrophy
• Right ventricular failure
• Tricuspid regurgitation
• Right-to-left shunting and cyanosis if patent foramen ovale present
• Increased risk of paradoxical emboli 1

Diagnostic Evaluation

Initial Assessment

• ECG: Right ventricular hypertrophy, right-axis deviation (in moderate to severe cases)
• Chest X-ray: Possible calcification of pulmonary valve, dilatation of pulmonary trunk and left pulmonary artery, right heart enlargement 1

Echocardiography

• First-line diagnostic technique
• Visualizes level of obstruction, valve anatomy, RV hypertrophy
• Doppler assessment provides gradient across obstruction
• Severity classification based on peak gradient:
  • Trivial: <25 mm Hg
  • Mild: 25-49 mm Hg
  • Moderate: 50-79 mm Hg
  • Severe: >80 mm Hg 1, 2

Cardiac Catheterization

• Indicated when Doppler peak jet velocity >3 m/second (estimated peak gradient >36 mm Hg)
• Provides definitive measurement of pressure gradient
• Allows for therapeutic intervention (balloon valvotomy) if indicated 1, 2

Management

Observation

• Asymptomatic patients with peak-to-peak gradient <30 mm Hg: Observation only 1, 2

Balloon Valvotomy

• Class I recommendation (strongly indicated):
  • Symptomatic patients (dyspnea, angina, syncope, presyncope) with gradient >30 mm Hg
  • Asymptomatic patients with gradient >40 mm Hg 1, 2
• Class IIb recommendation (may be reasonable):
  • Asymptomatic patients with gradient 30-39 mm Hg 1, 2
• Class III recommendation (not recommended):
  • Asymptomatic patients with gradient <30 mm Hg 1, 2

Surgical Intervention

• Reserved for cases where balloon valvotomy is unsuccessful or contraindicated
• May be needed for complex forms of stenosis (supravalvular, infundibular)
• 5-10% of patients may require surgical relief of residual valve or subvalvular stenosis 3

Management of Peripheral Pulmonary Stenosis

• Balloon pulmonary angioplasty for distal stenoses or those at branching points
• Stent implantation (>90% success rate) for central or proximal stenoses
• Surgical approach for supravalvar pulmonary stenosis or stenosis at branch pulmonary arteries bifurcation 4, 5

Follow-up and Monitoring

• Regular echocardiography every 5-10 years for stable cases
• More frequent monitoring for:
  • Children <2 years old
  • Initial gradients >40 mm Hg
  • Symptomatic patients 2

Common Pitfalls

• Misdiagnosing peripheral pulmonary stenosis as primary pulmonary arterial hypertension
• Underestimating progression risk in young children and those with higher gradients
• Delaying intervention in severe cases even when asymptomatic
• Overlooking associated cardiac defects
• Misinterpreting Doppler gradients (may overestimate severity in tubular stenosis) 1, 2