What is the recommended treatment for a patient diagnosed with an atrial septal defect?

Treatment of Atrial Septal Defect

For adults with secundum ASD causing right ventricular volume overload (Qp:Qs ≥1.5:1) and favorable pulmonary pressures, percutaneous device closure is recommended as first-line therapy, with surgical closure reserved for anatomically unsuitable defects. 1

Indications for ASD Closure

Class I Recommendations (Must Close)

Closure is mandatory when all of the following criteria are met: 1

• Hemodynamically significant left-to-right shunt (Qp:Qs ≥1.5:1) 1
• Right atrial and/or right ventricular enlargement 1
• PA systolic pressure <50% of systemic pressure 1
• Pulmonary vascular resistance <1/3 systemic resistance 1

Class IIb Recommendations (May Consider Closure)

Closure may be considered in borderline pulmonary hypertension when: 1

• Qp:Qs ≥1.5:1 with net left-to-right shunt 1
• PA systolic pressure is 50-67% of systemic pressure 1
• Pulmonary vascular resistance is 1/3 to 2/3 systemic resistance 1

This represents a gray zone where careful hemodynamic assessment and potentially vasoreactivity testing should guide decision-making. 2

Absolute Contraindications (Class III: Harm)

Never close an ASD when any of the following are present: 1, 2

• PA systolic pressure >2/3 systemic pressure 1
• Pulmonary vascular resistance >2/3 systemic resistance 1
• Net right-to-left shunt (Eisenmenger physiology) 1, 2

The presence of right-to-left shunting indicates severe irreversible pulmonary hypertension; closure would eliminate the "pop-off" mechanism allowing right ventricular decompression and could cause acute right heart failure and death. 2

Diagnostic Workup Before Closure

Essential Pre-Closure Assessments

Perform these evaluations in every patient being considered for closure: 1

• Pulse oximetry at rest and with exercise to detect shunt reversal 1
• Transthoracic echocardiography for initial assessment 1
• Transesophageal echocardiography or cross-sectional imaging (CMR/CCT) to define septal anatomy and pulmonary venous connections 1
• Cardiac catheterization when pulmonary hypertension is suspected to accurately measure PA pressures and calculate pulmonary vascular resistance 1, 2

Specific Shunt Assessment

Measure oxygen saturation in both hands and feet to assess for right-to-left shunting, as this indicates elevated pulmonary vascular resistance and contraindication to closure. 2

Treatment Modality Selection

Percutaneous Device Closure (First-Line)

Transcatheter closure is preferred for secundum ASDs when anatomically suitable because it offers: 3

• Significantly shorter hospital stay (mean difference -4.05 days in adults, -4.78 days in children) 3
• Fewer complications (OR 0.45 in adults, OR 0.26 in children) 3
• Equivalent mortality to surgical closure 3
• High complete closure rates with minimal patient discomfort 4

Anatomic suitability criteria for device closure: 5

• Secundum ASD typically ≤38 mm in diameter 5
• Adequate septal rims for device anchoring 5

Surgical Closure

Surgery is indicated when: 1, 5

• Large ASDs (>38 mm) 5
• Deficient septal rims precluding device placement 5
• Non-secundum defects (primum ASD, sinus venosus defect) 1
• Concomitant cardiac lesions requiring surgical repair 1

Both approaches show no difference in mortality, so anatomic factors should drive the decision. 3

Periprocedural Anticoagulation Protocol

At Time of Device Implantation

Administer unfractionated heparin 100 U/kg (maximum 5000 U) during the procedure (Class I recommendation). 1, 6

Post-Closure Antiplatelet Therapy

All patients require aspirin 100 mg daily for minimum 6 months after device closure (Class I recommendation for children, standard of care for adults). 1, 6

For older children and adults, consider dual antiplatelet therapy (aspirin plus clopidogrel) for 3-6 months (Class IIb recommendation), particularly in higher-risk patients. 1, 6

If complete closure is not achieved (residual shunt), continue thromboprophylaxis beyond 6 months due to ongoing paradoxical embolus risk. 6

High-Risk Patient Modifications

In patients with prior stroke, exclude inherited thrombophilic disorders before device implantation to adapt antithrombotic prophylaxis accordingly. 6

Special Considerations and Pitfalls

Pulmonary Hypertension Management

For patients with elevated pulmonary vascular resistance but not yet Eisenmenger physiology: 2

• Pretreatment with pulmonary arterial hypertension therapies demonstrating >20% reduction in pulmonary arterial resistance may allow safe closure 2
• This requires careful hemodynamic reassessment after medical optimization 2

Critical Pitfalls to Avoid

Do not close ASDs in patients with net right-to-left shunting as this represents Eisenmenger physiology and closure is contraindicated. 1, 2

Do not rely solely on transthoracic echocardiography in adults for defining septal anatomy and pulmonary venous connections; use TEE or cross-sectional imaging. 1

Do not omit exercise pulse oximetry as some patients with resting oxygen saturation >90% may desaturate to <90% with activity, indicating shunt reversal. 1

Do not discontinue aspirin before 6 months post-device closure unless compelling contraindications exist, as complete endothelialization requires this duration. 6

Do not forget procedural anticoagulation with UFH at the time of device implantation—this is a Class I recommendation. 1, 6

Long-Term Follow-Up

Patients require lifelong follow-up at specialized adult congenital heart disease centers due to time-related complications including arrhythmias, thromboembolism, and right heart failure, even after successful closure. 7