What is the recommended treatment for a pediatric patient with an Atrial Septal Defect (ASD)?

Treatment of Pediatric Atrial Septal Defect

For pediatric patients with hemodynamically significant secundum ASD and suitable anatomy, transcatheter device closure is the indicated treatment of choice, offering comparable outcomes to surgery with lower morbidity. 1

Treatment Algorithm Based on ASD Type and Hemodynamic Significance

Secundum ASD (Most Common - 7% of all congenital heart defects)

Class I Indication (Must Do):

• Transcatheter device closure is indicated for hemodynamically significant secundum ASD with suitable anatomic features 1
• Hemodynamic significance is defined as evidence of right-sided heart volume overload, right-sided heart failure, and/or elevation of right-sided heart pressures secondary to left-to-right shunting 1

Class IIa Indications (Should Do):

• Transcatheter closure is reasonable for patients with transient right-to-left shunting who have experienced paradoxical emboli (stroke or recurrent TIA) 1
• Transcatheter closure is reasonable for patients with transient right-to-left shunting who are symptomatic from cyanosis and don't require the communication for adequate cardiac output 1

Class IIb Indication (May Consider):

• Transcatheter closure may be considered for small secundum ASD in patients at risk of thromboembolic events (e.g., transvenous pacing systems, chronically indwelling IV catheters, hypercoagulable states) 1

Class III (Do Not Do):

• Transcatheter closure is NOT indicated for small secundum ASD with no hemodynamic significance and no other risk factors 1
• Transcatheter closure is contraindicated in patients with secundum ASD and advanced pulmonary vascular obstructive disease 1

Non-Secundum ASDs (Septum Primum, Sinus Venosus, Unroofed Coronary Sinus)

All non-secundum ASDs require surgical repair - transcatheter devices are not approved for these anatomic subtypes 1

Device Selection for Transcatheter Closure

Two FDA-approved devices are available in the United States 1:

AMPLATZER Septal Occluder:

• Suitable for all subtypes of secundum ASD 1
• Successfully closes defects up to 38 mm in diameter 1
• Composed of nitinol wire mesh encasing Dacron fabric 1
• Major complication rate: 1.6% (device embolism requiring surgery, cardiac arrhythmia requiring major treatment, cerebral embolism) 1
• Overall complication rate: 7.2% 1
• No patient deaths reported in the pivotal trial 1

HELEX Septal Occluder:

• Suitable for small to moderate defects (≤18 mm diameter) 1
• Composed of single nitinol strand bonded to microporous expanded polytetrafluoroethylene 1
• Not associated with device erosion 1
• Wire-frame fracture occurs in 5-7% of cases, though typically without clinical sequelae 1

Timing and Patient Selection

Age and Weight Considerations:

• Both devices can be implanted successfully in children ≥2 years of age 1
• Weight of 15 kg offers technical advantages and simplifies the procedure, though not an absolute requirement 1
• Percutaneous closure can be performed safely in low-weight infants (<15 kg) with comparable complication rates to larger children 2

Anatomic Requirements:

• Suitable anatomic defects require enough septal rim surrounding the defect to ensure device stability 1
• Defects with deficiencies of inferior, posterior, and superior rims can still be successfully closed with newer devices 1
• Device seating must not interfere with atrioventricular valves or pulmonary veins 1

Procedural Anticoagulation Protocol

At Time of Implantation:

• Administer at least 100 U/kg UFH (up to 5000-U maximum dose) 1

Post-Procedure:

• Low-dose aspirin for at least 6 months after implantation 1
• For older children and adults, another anticoagulant may be considered in addition to aspirin for 3-6 months 1
• If complete defect closure is not achieved (residual shunt), continue thromboprophylaxis beyond 6 months due to ongoing paradoxical embolus risk 1

Critical Complications to Monitor

Life-Threatening Complications:

• Cardiac erosion/perforation leading to tamponade and death 1
• Device migration/embolization requiring surgical removal 1
• Cerebral embolism 1

Common Complications:

• Cardiac arrhythmias (most common delayed complication) 1
• Atrioventricular block 1
• Device thrombosis 1

Surgical Closure Indications

Surgery remains the treatment of choice for:

• Neonates, infants, and children <3 years of age with large defects 1
• All non-secundum ASD types 1
• Secundum ASDs with unsuitable anatomy for device closure 1
• Complex cases in children with aneurysmal, multi-fenestrated, or malaligned septum 3

Surgical closure is safe, effective, and time-tested but requires open heart surgery, cardiopulmonary bypass, and longer hospitalization 1

Follow-Up and Imaging

Echocardiography (TTE) is preferred for:

• Routine surveillance within the first year after device closure 4
• Monitoring at 1 week, 1 month, 3-6 months, and 1 year post-device 4

Cardiac MRI:

• May be appropriate for routine surveillance after the first year following surgical closure 4
• Appropriate for evaluation due to change in clinical status or new symptoms after closure 4
• Generally wait at least 6 weeks after device implantation before MRI to allow complete endothelialization 4
• Both AMPLATZER and HELEX devices are MRI compatible (nitinol composition) 4

Key Clinical Pitfall

Do not delay closure in hemodynamically significant ASDs - untreated defects result in right-sided heart failure, arrhythmia, and pulmonary hypertension 1. Early repair prevents hemodynamic complications including development of pulmonary hypertension and cardiac arrhythmias 5. Patients benefit from closure regardless of age, but earlier intervention prevents long-term complications 5.