What are the indications for atrial septal defect (ASD) closure in symptomatic adults?

Indications for ASD Closure in Adults

ASD closure (percutaneous or surgical) is indicated in adults with right atrial and right ventricular enlargement, with or without symptoms, to prevent premature mortality and progressive morbidity. 1

Class I Indications (Definitive - Should Be Done)

The primary indication is right heart enlargement regardless of symptom status:

• Closure is indicated when right atrial and/or RV enlargement is present, typically with Qp:Qs ≥1.5:1, even in asymptomatic patients. 1, 2, 3 This is the cornerstone indication because symptoms lag behind objective cardiopulmonary dysfunction and cannot reliably guide therapy. 3

Critical hemodynamic requirements must be met:

• Pulmonary artery systolic pressure must be <50% of systemic pressure 2, 3
• Pulmonary vascular resistance must be <1/3 systemic vascular resistance (<5 Wood units) 2, 3
• Net left-to-right shunt must be present (no cyanosis) 2

Defect-specific surgical requirements:

• Sinus venosus, coronary sinus, and primum ASDs must be repaired surgically rather than percutaneously 1, 3
• Surgeons with training and expertise in congenital heart disease should perform these operations 1

Class IIa Indications (Reasonable - Should Probably Be Done)

Special clinical scenarios where closure is reasonable:

• Paradoxical embolism: Closure is reasonable when paradoxical embolism has occurred, after excluding other embolic sources 1, 3
• Orthodeoxia-platypnea syndrome: Documented cases warrant closure 1
• Concomitant cardiac surgery: When another cardiac procedure is being performed and Qp:Qs ≥1.5:1 with RV enlargement exists, closure should be performed even if the ASD was not the primary surgical indication 2, 3
• Tricuspid valve pathology: Surgical closure is reasonable when concomitant tricuspid valve repair/replacement is needed 1

Class IIb Indications (May Be Considered - Requires Expert Evaluation)

Borderline pulmonary hypertension cases require careful assessment:

• Closure may be considered when PA systolic pressure is 50-67% of systemic pressure AND/OR PVR is 1/3 to 2/3 of systemic resistance, provided there is still a net left-to-right shunt and evidence of pulmonary vascular reactivity 1, 2
• These patients must be evaluated by pulmonary hypertension specialists before proceeding 1, 2, 3
• Test occlusion or vasodilator responsiveness testing may guide decision-making 1

Arrhythmia management:

• Concomitant Maze procedure may be considered for intermittent or chronic atrial tachyarrhythmias 1

Class III Indications (Should NOT Be Done - Contraindicated)

Absolute contraindications to closure:

• Severe irreversible pulmonary arterial hypertension with no evidence of left-to-right shunt (Eisenmenger physiology) 1, 2
• PA systolic pressure >2/3 systemic pressure 2, 4
• PVR >2/3 systemic vascular resistance 2, 4
• Net right-to-left shunt present 2, 4

Closure in these circumstances causes acute right ventricular failure and death. 2

Defects That Do NOT Require Closure

Small ASDs without hemodynamic significance:

• Defects <5 mm diameter without RV volume overload do not require closure 1, 2, 3
• These patients should be monitored with echocardiography every 2-3 years to assess RV size, function, and pulmonary pressure 1
• Exception: Even small defects should be closed if paradoxical embolism has occurred 2, 3

Critical Pitfalls to Avoid

Do not delay closure based on absence of symptoms:

• Symptoms are an unreliable guide because they lag behind objective cardiac dysfunction 3
• Unoperated ASDs result in 25% mortality before age 27 and 90% mortality by age 60 2, 3, 4
• Surgery after age 25 results in reduced survival compared to age-matched controls 3

Do not assume small shunts remain benign in older adults:

• Acquired conditions (hypertension, coronary disease, valvular disease) reduce LV compliance and increase left-to-right shunting over time 1, 2
• Previously insignificant ASDs can become hemodynamically relevant with aging 2

Do not close ASDs without excluding severe pulmonary hypertension:

• This is the most critical assessment before closure 2
• Closure with established severe pulmonary vascular disease is contraindicated and fatal 2, 4

Preferred Closure Method

Percutaneous device closure is preferred for secundum ASDs when anatomically suitable:

• Stretched diameter <38 mm with adequate rim ≥5 mm in most locations 3, 4
• Device closure has comparable efficacy to surgery with lower morbidity, shorter hospital stay, no sternotomy, and faster recovery 5, 6, 7
• Serious complications occur in ≤1% of patients with device closure 3
• Early mortality is approximately 1% in the absence of PAH or major comorbidities 1, 3