Management of Secundum Atrial Septal Defect (ASD)

Indications for Closure

The American College of Cardiology recommends closure of secundum ASD for patients with right atrial and right ventricular enlargement, with or without symptoms, to prevent long-term complications such as atrial arrhythmias, reduced exercise tolerance, and pulmonary vascular disease 1, 2
Closure is indicated for patients with right atrial and right ventricular enlargement with or without symptoms, as recommended by the American Heart Association 1, 2
Percutaneous device closure is preferred for secundum ASD when anatomically suitable, according to the American College of Cardiology 1, 3

Closure Methods

Surgical closure is indicated for sinus venosus, coronary sinus, or primum ASD, as these are not amenable to device closure, as stated by the American Heart Association 1, 3

Post-Procedure Management

The American College of Cardiology recommends monitoring for symptoms of undue fever, fatigue, vomiting, chest pain, or abdominal pain which may indicate postpericardiotomy syndrome with tamponade after ASD closure 4, 3, 5
Echocardiography should be performed to assess device position and stability, residual shunting, pericardial effusion, and right ventricular function after ASD closure, as recommended by the American Society of Echocardiography 3, 5

Clinical Outcomes

Closure of ASD is associated with improvement in New York Heart Association functional class, right ventricular systolic pressure, volumes, and dimensions, according to the American College of Cardiology 6, 7
The American College of Cardiology states that closure is associated with a weak protective effect on adjusted mortality rate 6, 7
Early mortality is approximately 1% in the absence of PAH or other major comorbidities, as reported by the American Heart Association 1, 3

Special Considerations

Small ASDs (<5 mm) without evidence of RV volume overload generally do not require closure unless associated with paradoxical embolism, as stated by the American College of Cardiology 4, 1, 3
Patients with severe pulmonary hypertension require careful evaluation by providers with expertise in pulmonary hypertensive syndromes before considering closure, according to the American Thoracic Society 4, 1

Atrial Septal Defect Management Goals

Primary Mortality and Morbidity Prevention

Nearly 25% of patients with unoperated atrial septal defects die before age 27, and 90% by age 60, making closure essential to prevent premature death, as recommended by the American College of Cardiology and American Heart Association 8, 9
The left-to-right shunt causes progressive right ventricular volume overload leading to right heart failure with fatigue and exercise intolerance, according to the American College of Cardiology 9
Atrial enlargement from volume overload leads to age-related atrial arrhythmias with increased thromboembolic risk, even after repair, as noted by the American College of Cardiology 9
Long-term shunting can lead to severe pulmonary hypertension with significant morbidity, as reported in Circulation 8

Specific Hemodynamic Goals

Closure aims to restore functional capacity, particularly in patients over 40 years of age, with improvement in exercise tolerance, as recommended by the American College of Cardiology and American Heart Association 8, 9

Functional Status Improvement

Pooled analysis shows a protective effect on functional status after closure, with improvement in NYHA functional class, according to the American College of Cardiology 9
Objective echocardiographic improvements in right heart parameters, including reduction in right ventricular systolic pressure, volumes, and dimensions, are expected after closure, as noted by the American College of Cardiology 9

Critical Timing Considerations

Surgery performed after age 25 years results in reduced survival compared to age-matched controls, emphasizing the importance of earlier intervention, as reported in Circulation 8, 9
Delaying closure based on absence of symptoms is a key pitfall, as symptoms lag behind objective cardiopulmonary dysfunction and cannot guide therapy, according to Circulation 8, 10

ASD Secundum Mortality Risk and Treatment

Introduction to ASD Secundum

The American College of Cardiology states that a stable uncomplicated secundum ASD is not immediately life-threatening, but it carries significant long-term mortality risk if left untreated, with nearly 25% of patients dying before age 27 and 90% by age 60 11

Understanding the Natural History

Patients with small defects (<10 mm) may remain asymptomatic well into their fourth and fifth decades of life, according to the American Heart Association 12, 13
The term "stable and uncomplicated" typically means no current pulmonary hypertension, no right heart failure, and no significant arrhythmias, as defined by the European Society of Cardiology 12
The European Society of Cardiology recommends that patients with right atrial and right ventricular enlargement should undergo closure regardless of symptoms (Class I, Level B) 14

Long-Term Mortality Risk

Unoperated ASDs have reduced life expectancy with 25% mortality before age 27 and 90% mortality by age 60, as reported by the American College of Cardiology 11
Even when surgery is performed after age 25 years, survival remains reduced compared to age- and sex-matched controls, according to the American College of Cardiology 11

Clinical Implications

Closure prevents the progressive mortality seen in natural history studies, and outcome is best with repair before age 25 years, as stated by the European Heart Journal 11, 14
Patients benefit from closure at any age regarding morbidity (exercise capacity, shortness of breath, right heart failure), according to the European Society of Cardiology 14
Device closure has become the first choice for secundum defects when feasible (stretched diameter <38 mm with sufficient rim), as recommended by the European Heart Journal 14
Serious complications occur in ≤1% of patients with device closure, as reported by the European Society of Cardiology 14

Current Recommendations for ASD Closure Eligible by Device Criteria

Primary Indications for Device Closure

The American College of Cardiology recommends device closure for adults with isolated secundum ASD causing impaired functional capacity, right atrial and/or RV enlargement, and Qp:Qs ≥1.5:1 without cyanosis, when PA systolic pressure <50% systemic and PVR <1/3 systemic resistance, with a Class I Recommendation 15
The goal of device closure is to reduce RV volume overload and improve exercise tolerance, with a Class I Recommendation 15

Critical Hemodynamic Thresholds

The American College of Cardiology recommends proceeding with device closure when PA systolic pressure <50% of systemic pressure 16, 15
The European Heart Journal suggests proceeding with device closure when PVR <1/3 systemic vascular resistance (<5 Wood units) 17
Device closure is recommended when Qp:Qs ≥1.5:1 with evidence of RV volume overload, with a Class I Recommendation 16, 15, 17

Device-Specific Anatomic Criteria

The European Heart Journal suggests that secundum ASD with stretched diameter <38mm is favorable for device closure 17
Adequate rim of ≥5mm in most locations (except toward the aorta where smaller rim acceptable) is recommended for device closure, with a Class I Recommendation 17

Special Clinical Scenarios

The European Heart Journal recommends device closure for ASDs of any size when paradoxical embolism is suspected after excluding other causes 17, 18
The American College of Cardiology suggests surgical closure when another cardiac procedure is being performed and Qp:Qs ≥1.5:1 with RV enlargement, even if ASD was not the primary indication, with a Class IIa Recommendation 16, 15

Defects NOT Eligible for Device Closure

The American College of Cardiology and the European Heart Journal suggest that sinus venosus defects, coronary sinus defects, primum ASDs, and ASDs with anomalous pulmonary venous drainage require surgical repair rather than device closure 15, 17, 18

Expected Outcomes

The European Heart Journal reports that serious complications occur in ≤1% of patients undergoing device closure 17
The Circulation journal reports that early mortality is approximately 1% in the absence of PAH or major comorbidities 18

Management of Secundum Atrial Septal Defect

Primary Recommendation

The American College of Cardiology recommends proceeding with closure if all of the following are met: Qp:Qs ≥1.5:1 with evidence of RV volume overload, PA systolic pressure <50% of systemic pressure, pulmonary vascular resistance <1/3 systemic resistance (<5 Wood units), and net left-to-right shunt present, to prevent premature death 19

Treatment Algorithm Based on Hemodynamics and Anatomy

The American College of Cardiology suggests considering closure with caution when PA systolic pressure is 50% or more of systemic pressure AND/OR PVR is greater than 1/3 systemic resistance, and net left-to-right shunt (Qp:Qs ≥1.5:1) is still present, with evaluation by pulmonary hypertension experts before proceeding 19, 20

Percutaneous Device Closure of Secundum Atrial Septal Defects – Evidence‑Based Recommendations

Device Selection and Anatomic Criteria

The defect must have a stretched (balloon‑sized) diameter < 38 mm to be eligible for percutaneous closure 21.
Patients weighing ≥ 15 kg experience technical advantages during device deployment 21.
The Amplatzer Septal Occluder is approved for defects up to 38 mm, constructed of nitinol wire mesh with Dacron fabric, and can be repositioned before release [21][22].
The HELEX Septal Occluder is indicated for small‑to‑moderate defects (≤ 18 mm), made of nitinol covered with expanded polytetrafluoroethylene, and remains repositionable even after partial release [21][22].

Pre‑Procedural Imaging

Transesophageal echocardiography (TEE) or intracardiac echocardiography (ICE) should be performed to determine defect size, rim adequacy, and to guide device deployment [21][23].

Intra‑Procedural Guidance

Device deployment must be performed under real‑time echocardiographic guidance with assessment of position and stability before release 21.

Complication Profile – Major Events

The overall major complication rate with the Amplatzer device is 1.6 % [21][22].
Device embolization requiring surgical retrieval occurs as a serious immediate risk 22.
Cardiac erosion or perforation leading to tamponade and possible death has been reported 21.
Significant cardiac arrhythmias that necessitate major therapeutic intervention have been observed 23.
Cerebral embolic events with neurologic sequelae have been documented 22.
Atrioventricular (AV) block is another reported major adverse event 21.

Complication Profile – Minor Events

Minor complications occur in 6.1 % of cases 22.
The most frequent minor issue is transient arrhythmia 21.
Thrombus formation on the device surface has been reported 22.
With the HELEX device, wire‑frame fracture is seen in 5–7 % of implants, usually without clinical consequence 22.