What is the recommended management for a patient with a secundum-type atrial septal defect?

Management of Secundum Atrial Septal Defect

Primary Recommendation

Closure is recommended for all secundum ASDs causing right atrial and right ventricular enlargement, regardless of symptoms, to prevent premature death—with 25% mortality before age 27 and 90% mortality by age 60 if left unoperated. 1, 2

---

Treatment Algorithm Based on Hemodynamics and Anatomy

Step 1: Assess Hemodynamic Criteria for Closure

Proceed with closure if ALL of the following are met:

• Qp:Qs ≥1.5:1 with evidence of RV volume overload 3, 1, 2
• PA systolic pressure <50% of systemic pressure 3, 1, 2
• Pulmonary vascular resistance <1/3 systemic resistance (<5 Wood units) 3, 1, 2
• Net left-to-right shunt present (no cyanosis) 1, 2

Critical timing consideration: Surgery performed after age 25 results in reduced survival compared to age-matched controls, making earlier intervention essential even in asymptomatic patients. 1 Delaying closure based on absence of symptoms is a key pitfall, as symptoms lag behind objective cardiopulmonary dysfunction. 1

Step 2: Select Closure Method Based on Anatomy

Percutaneous Device Closure (Preferred First-Line)

Use device closure when anatomically suitable: 1, 2

• Secundum ASD with stretched diameter <38 mm 1, 2
• Adequate rim ≥5 mm in most locations (smaller rim acceptable toward aorta) 1, 2
• No associated anomalous pulmonary venous drainage 1

Device closure advantages: Lower mortality (RR 0.66), lower total complications (RR 0.48), lower major complications (RR 0.57), and shorter hospital stay compared to surgery. 4 Serious complications occur in ≤1% of patients. 1

Device closure disadvantages: Higher rate of residual shunting (RR 3.35) compared to surgery. 4

Surgical Closure (Required for Specific Scenarios)

Mandatory surgical approach for: 1, 2

• Sinus venosus defects 1, 2
• Coronary sinus defects 1, 2
• Primum ASDs 1, 2
• ASDs with anomalous pulmonary venous drainage 1
• Secundum ASDs not anatomically suitable for device (stretched diameter >38 mm or inadequate rims) 1, 2
• Concomitant need for tricuspid valve repair/replacement 2
• When another cardiac procedure is being performed and Qp:Qs ≥1.5:1 with RV enlargement 2

Surgical outcomes: Early mortality approximately 1% in absence of PAH or major comorbidities. 1

---

Special Clinical Scenarios

Small ASDs (<5 mm)

Do not close unless: 1

• Evidence of RV volume overload present 1
• Paradoxical embolism suspected (after excluding other causes) 1, 2

Borderline Pulmonary Hypertension

Consider closure with caution when: 3

• PA systolic pressure is 50% or more of systemic pressure AND/OR 3
• PVR is greater than 1/3 systemic resistance 3
• Net left-to-right shunt (Qp:Qs ≥1.5:1) still present 3

Require evaluation by pulmonary hypertension experts before proceeding. 1

Absolute Contraindications to Closure

Do NOT close when: 2

• PA systolic pressure >2/3 systemic pressure 2
• PVR >2/3 systemic resistance 2
• Net right-to-left shunt present (Eisenmenger physiology) 2
• Severe irreversible PAH with no evidence of left-to-right shunt 2

---

Post-Closure Monitoring and Complications

Immediate Post-Procedure Assessment

Perform echocardiography to assess: 1

• Device position and stability 1
• Residual shunting 1
• Pericardial effusion 1
• Right ventricular function 1

Monitor for Postpericardiotomy Syndrome

Watch for symptoms indicating potential tamponade: 1, 2

• Undue fever 1, 2
• Fatigue 1, 2
• Vomiting 1, 2
• Chest pain 1, 2
• Abdominal pain 1, 2

Perform immediate echocardiography if these symptoms develop. 2

Long-Term Complications (Device Closure)

Rare but potentially life-threatening delayed complications include: 5

• Cardiac erosion (most severe) 5
• Device thrombosis 5
• Atrial arrhythmias (most common) 5
• Nickel allergy 5
• Cardiac conduction abnormalities 5
• Valvular damage 5
• Device endocarditis 5

---

Expected Clinical Outcomes

Closure improves: 1, 2

• NYHA functional class 1, 2
• Right ventricular systolic pressure 1, 2
• Right ventricular volumes and dimensions 1, 2
• Exercise tolerance 1, 2
• Adjusted mortality rate (weak protective effect) 1

Best outcomes achieved with repair before age 25 years. 1, 2

---

Key Pitfalls to Avoid

Do not assume asymptomatic status means no intervention needed—objective RV enlargement mandates closure regardless of symptoms, as functional decline occurs before symptom onset. 1, 2

Do not delay closure waiting for symptoms to develop—this results in irreversible pulmonary vascular changes and worse long-term survival. 1

Meticulous air bubble elimination from all IV lines is mandatory during any procedure in ASD patients due to paradoxical embolism risk. 6