When should an atrial septal defect (ASD) be closed?

From the Guidelines

Atrial septal defects (ASDs) should be closed when they are hemodynamically significant, typically defined as having a pulmonary-to-systemic flow ratio (Qp:Qs) greater than 1.5:1, or when they cause symptoms such as exercise intolerance, fatigue, palpitations, or shortness of breath, as recommended by the 2019 AHA/ACC guideline for the management of adults with congenital heart disease 1. The decision to close an ASD is based on several factors, including the size of the defect, the presence of symptoms, and the risk of long-term complications.

• Hemodynamically significant ASDs, typically defined as those with a Qp:Qs ratio greater than 1.5:1, should be closed to prevent long-term complications such as right heart enlargement, pulmonary hypertension, arrhythmias, and heart failure 1.
• Symptomatic patients, regardless of age, should undergo ASD closure to improve exercise tolerance and reduce symptoms 1.
• Asymptomatic patients with significant shunts (Qp:Qs ratio greater than 1.5:1) may also benefit from closure to prevent long-term complications, provided that systolic PA pressure is less than 50% of systolic systemic pressure and pulmonary vascular resistance is less than one third of the systemic vascular resistance 1.
• Small ASDs (less than 5-8 mm) with minimal shunting and no cardiac enlargement may be monitored without intervention, as they are unlikely to cause significant hemodynamic effects or long-term complications 1. The procedure for ASD closure can be performed via catheter-based device closure for secundum ASDs with adequate rims or surgical repair for primum ASDs, sinus venosus defects, or large secundum defects unsuitable for device closure 1.
• Percutaneous or surgical closure may be considered for adults with ASD when net left-to-right shunt (Qp:Qs) is 1.5:1 or greater, PA systolic pressure is 50% or more of systemic arterial systolic pressure, and/or pulmonary vascular resistance is greater than one third of the systemic resistance 1.
• However, ASD closure should not be performed in adults with PA systolic pressure greater than two thirds systemic, pulmonary vascular resistance greater than two thirds systemic, and/or a net right-to-left shunt 1. Following closure, patients typically require antiplatelet therapy with aspirin 81-325 mg daily for at least six months after device placement, and endocarditis prophylaxis for six months after device closure or lifelong after surgical repair with prosthetic material 1.

From the Research

Indications for Atrial Septal Defect (ASD) Closure

• ASD closure is recommended in patients with right heart enlargement or paradoxical embolism 2
• Indications for ASD closure include a history of thromboembolism, decreased exercise tolerance, atrial arrhythmias, evidence of pulmonary hypertension or right heart overload 3
• Patients with anatomically large ASD and a high probability of reversible pulmonary vascular disease may benefit from ASD closure despite severe pulmonary hypertension 4

Contraindications for ASD Closure

• Large ASDs (>38 mm) and defects with deficient rims are usually not offered transcatheter closure but are referred for surgical closure 5
• Transcatheter closure may be controversial for complicated ASDs with comorbidities, additional cardiac features, and in small children 5

Considerations for ASD Closure

• The decision-making process for ASD closure in adults can be complex, especially in patients with advanced age, concomitant diseases, poor LV function, pulmonary hypertension, concomitant arrhythmias, or multiple defects 2
• Available data are predominantly focused on imaging endpoints and short-term morbidity and mortality rather than long-term outcomes 2
• The clinical experience in diagnosing and treating ASD patients can be inhomogeneous between individual physicians and centers 2

Outcomes of ASD Closure

• Percutaneous ASD closure using the Amplatzer Septal Occluder is safe and mid-term results compare favorably with those reported with surgical ASD closure 3
• The MemoPart ASD occluder is a safe and effective device for ASD closure, even in wide ASDs and complicated cases 6
• Patients with severe pulmonary hypertension may benefit from ASD closure and pulmonary vasodilators, despite significantly elevated pulmonary artery pressure and pulmonary vascular resistance 4