What are the current management guidelines for patients with atrial septal defects?

Management Guidelines for Atrial Septal Defects

Closure of atrial septal defects (ASDs) is recommended in adults with evidence of right ventricular volume overload when there is a net left-to-right shunt (Qp:Qs ≥1.5:1), pulmonary artery systolic pressure less than 50% systemic, and pulmonary vascular resistance less than one-third systemic. 1

Types of ASDs and Diagnostic Evaluation

ASDs are classified into four main types:

• Secundum ASD (most common)
• Primum ASD
• Sinus venosus defect
• Coronary sinus defect

Diagnostic Workup

1. Pulse oximetry at rest and with exercise to define shunt direction 1

   • Identifies patients with increased pulmonary arterial resistance
   • Detects exercise-induced desaturation (<90%)

2. Imaging studies:

   • TTE (transthoracic echocardiography): First-line imaging to assess defect size, shunt direction, and right heart enlargement
   • TEE (transesophageal echocardiography): Superior for visualization of entire atrial septum and pulmonary venous connections 1
   • CMR/CCT: Ideal for delineating pulmonary venous connections and anomalous pulmonary veins 1

3. Cardiac catheterization:

   • Useful when pulmonary hypertension is suspected
   • Determines pulmonary vascular resistance and shunt magnitude (Qp:Qs ratio) 1

Management Guidelines

Indications for ASD Closure

1. Strong indications for closure (Class I):

   • Right atrial and RV enlargement with net left-to-right shunt (Qp:Qs ≥1.5:1)
   • PA systolic pressure <50% systemic
   • Pulmonary vascular resistance <1/3 systemic 1

2. Reasonable to consider closure (Class IIa):

   • Paradoxical embolism
   • Documented orthodeoxia-platypnea
   • Small shunt (Qp:Qs <1.5:1) in presence of symptoms 1

3. May consider closure (Class IIb):

   • Net left-to-right shunt (Qp:Qs ≥1.5:1) with PA systolic pressure ≥50% systemic
   • Pulmonary vascular resistance >1/3 but <2/3 systemic 1

4. Contraindications to closure (Class III: Harm):

   • PA systolic pressure >2/3 systemic
   • Pulmonary vascular resistance >2/3 systemic
   • Net right-to-left shunt 1

Closure Methods

1. Percutaneous device closure:

   • Preferred for secundum ASDs when anatomically suitable
   • Benefits: shorter hospital stay, avoidance of sternotomy, lower cost, rapid recovery 2
   • Devices include Amplatzer® Septal Occluder (most common), Amplatzer® Cribriform device (for fenestrated ASDs), and Gore HELEX® device (for small-medium defects) 2

2. Surgical closure:

   • Required for primum ASDs, sinus venosus defects, and coronary sinus defects
   • Indicated for secundum ASDs with unsuitable anatomy for device closure
   • Recommended when concomitant cardiac surgery is being performed 1

Special Considerations

Age-Related Factors

• While historically controversial, current evidence supports ASD closure at the time of presentation in adults 2
• Studies show improvement in functional status and right ventricular size/function after closure in adults >40 years 3
• Without repair, adults with ASDs experience higher rates of exercise intolerance, atrial arrhythmias, right ventricular dysfunction, and reduced life expectancy 4

Pulmonary Hypertension

• Careful assessment of pulmonary pressures is essential before closure
• Patients with borderline elevated pulmonary pressures require expert evaluation
• Management by a team with expertise in both ACHD and pulmonary hypertension is recommended 1

Post-Closure Follow-Up

• Monitor for residual shunts, device complications, and arrhythmias
• Follow-up echocardiography at 24 hours, 6 months, and yearly thereafter 3
• Most patients show decreased right ventricular dimensions and improved symptoms after closure 3, 5

Pitfalls and Caveats

1. Misdiagnosis: Poor visualization of superior/posterior atrial septum by TTE may miss sinus venosus defects; always consider TEE, CMR, or CCT when clinical suspicion is high 1

2. Inappropriate closure: Closing ASDs in patients with severe pulmonary hypertension can worsen outcomes; thorough hemodynamic assessment is crucial 1

3. Associated lesions: ASDs may occur with other congenital defects (e.g., Ebstein anomaly, pulmonary stenosis); in these cases, ASD closure could cause clinical deterioration 1

4. Arrhythmias: Atrial arrhythmias may persist or develop even after closure, particularly in older patients 6

By following these guidelines, clinicians can optimize outcomes for patients with atrial septal defects while minimizing morbidity and mortality associated with untreated defects or inappropriate interventions.