Is surgical closure of a 5-6 mm secundum atrial septal defect (ASD) recommended in a 4-year-old patient with Noonan syndrome, without hypertrophic cardiomyopathy?

Management of Secundum Atrial Septal Defect in a 4-Year-Old with Noonan Syndrome Without Hypertrophic Cardiomyopathy

Surgical closure is recommended for this 5-6 mm secundum atrial septal defect in a 4-year-old with Noonan syndrome, even without hypertrophic cardiomyopathy. 1, 2

Rationale for Surgical Closure

Size and Age Considerations

• The ASD is 5-6 mm, which is at the borderline of what guidelines consider potentially significant
• According to ACC/AHA guidelines, ASDs smaller than 5 mm with no evidence of right ventricular volume overload may not require closure 1
• However, in this case:
  • The defect is 5-6 mm, which exceeds the lower threshold
  • Elective ASD closure is typically recommended around 4 years of age 2
  • The patient has Noonan syndrome, which increases risk factors for complications

Noonan Syndrome Considerations

• Noonan syndrome is the second most common syndromic cause of congenital heart disease 3
• Even without hypertrophic cardiomyopathy, patients with Noonan syndrome may have:
  • Atypical septal anatomy that can complicate device closure
  • Higher risk of arrhythmias
  • Potential for other cardiac abnormalities that may develop over time

Surgical vs. Device Closure

Why Surgical Closure is Preferred in This Case

• Surgical closure is considered the "gold standard" for ASD repair, with excellent long-term outcomes and a mortality rate of approximately 1% in the absence of pulmonary hypertension 1
• For patients with syndromic conditions like Noonan syndrome, surgical closure offers:
  • Direct visualization of the defect and surrounding anatomy
  • Ability to address any unexpected anatomical variations
  • Lower risk of complications compared to device closure in patients with atypical anatomy 2

Device Closure Limitations

• Device closure has a 7.2% overall complication rate 1
• Complications include:
  • Device migration/embolization
  • Cardiac erosion/perforation leading to tamponade
  • Arrhythmias
  • Thrombus formation
• Patients with syndromic conditions like Noonan syndrome have higher risk of device-related complications 2

Surgical Approach

• Primary surgical options include:
  • Pericardial patch closure
  • Direct suture closure
• Minimally invasive approaches can be considered:
  • Ministernotomy
  • Thoracoscopic approach 1

Postoperative Care and Follow-up

• Annual clinical follow-up is recommended after ASD repair to monitor for:
  • Pulmonary arterial hypertension
  • Atrial arrhythmias
  • RV or LV dysfunction 1
• Early postoperative symptoms requiring immediate evaluation include:
  • Undue fever
  • Fatigue
  • Vomiting
  • Chest pain
  • Abdominal pain 1

Potential Benefits of Closure

• Prevention of long-term complications:
  • Atrial arrhythmias
  • Reduced exercise tolerance
  • Hemodynamically significant tricuspid regurgitation
  • Right-to-left shunting during pregnancy
  • Congestive cardiac failure
  • Pulmonary vascular disease 1
• Early surgical closure has been shown to improve clinical status in symptomatic young children with underlying pulmonary abnormalities 4

Pitfalls to Avoid

• Delaying closure may lead to:
  • Progressive right heart enlargement
  • Development of arrhythmias
  • Eventual pulmonary hypertension
• In patients with Noonan syndrome, careful evaluation for other cardiac anomalies is essential, as they may have multiple cardiac defects 3, 5
• Careful monitoring for complete heart block is necessary post-surgery, especially if any septal reconstruction is required 6

By proceeding with surgical closure at this age, the patient has the best opportunity for normal cardiac development and prevention of long-term complications associated with unrepaired ASDs.