Should a 5-6 mm secundum atrial septal defect (ASD) with left to right shunt in a 4-year-old Noonan syndrome patient be closed via catheter lab device placement or open heart surgery?

Management of Secundum Atrial Septal Defect in a 4-Year-Old with Noonan Syndrome

For a 4-year-old with Noonan syndrome and a 5-6 mm secundum atrial septal defect with left-to-right shunt, surgical closure is the preferred approach over catheter lab device placement due to the increased risks associated with device closure in Noonan syndrome patients.

Rationale for Surgical Approach in This Patient

Anatomical Considerations

• The AHA/ACC guidelines classify secundum ASDs as potentially amenable to device closure 1
• However, patients with Noonan syndrome often have:
  • Atypical septal anatomy that may complicate device placement 2
  • Higher risk of associated hypertrophic cardiomyopathy, which increases device-related complications 2, 3
  • Potential deficient rims that make device closure technically challenging 2

Size Considerations

• The 5-6 mm defect size is at the borderline of hemodynamic significance
• Guidelines state that ASDs smaller than 5 mm with no evidence of RV volume overload may not require closure 1
• However, even moderate increases in pulmonary blood flow from ASDs can have negative clinical impacts in certain populations 4

Age-Related Factors

• At 4 years of age, the patient is at an appropriate age for elective ASD closure
• While device closure can be performed in children as young as 2 years (or 15 kg), surgical closure remains the gold standard with excellent outcomes 1

Comparison of Closure Methods

Device Closure Considerations

• Advantages:

  • Less invasive approach with quicker recovery 5
  • Reduced physical and psychological impact 5

• Risks/Complications (7.2% overall complication rate) 1:

  • Device migration/embolization
  • Cardiac erosion/perforation leading to tamponade
  • Arrhythmias
  • Thrombus formation
  • Potential for device-related complications in Noonan syndrome patients with atypical anatomy 2

Surgical Closure Considerations

• Advantages:

  • "Gold standard" with excellent late outcomes 1
  • More appropriate for patients with syndromic conditions that may affect septal anatomy 2
  • Allows direct visualization of the defect and any associated anomalies
  • Mortality approximately 1% in absence of pulmonary hypertension 1

• Risks:

  • More invasive procedure requiring sternotomy or thoracotomy
  • Longer recovery time
  • Postpericardiotomy syndrome (rare)

Decision Algorithm

1. Assess defect type: Confirm secundum ASD (already established)
2. Evaluate hemodynamic significance:
   • Presence of left-to-right shunt (confirmed)
   • Assess for RV enlargement
3. Consider patient-specific factors:
   • Noonan syndrome increases risk with device closure
   • Evaluate for hypertrophic cardiomyopathy (common in Noonan syndrome)
4. Choose closure method:
   • If standard secundum ASD with no complicating factors: Consider device closure
   • If Noonan syndrome with potential anatomical variations: Surgical closure preferred

Post-Procedure Management

• Annual clinical follow-up is recommended after ASD repair 1
• Monitor for:
  • Pulmonary arterial hypertension
  • Atrial arrhythmias
  • RV or LV dysfunction
  • Early postoperative symptoms that may indicate postpericardiotomy syndrome 1

Conclusion

Given the patient's young age, Noonan syndrome diagnosis, and the potential for atypical septal anatomy or associated cardiac abnormalities, surgical closure represents the safest and most effective approach for this 4-year-old with a 5-6 mm secundum ASD.