What is the management for a patient with aneurysm (an abnormal dilation) of the atrial septum with a left to right shunt?

Management of Atrial Septal Aneurysm with Left-to-Right Shunt

For an atrial septal aneurysm (ASA) with left-to-right shunt causing right ventricular enlargement and hemodynamically significant shunting (Qp:Qs ≥1.5:1), closure is recommended via transcatheter or surgical approach, provided pulmonary artery systolic pressure is less than 50% of systemic pressure and pulmonary vascular resistance is less than one-third systemic resistance. 1

Initial Diagnostic Evaluation

Confirm the diagnosis and assess hemodynamic significance through:

• Transesophageal echocardiography (TEE) is the gold standard for visualizing ASA and associated atrial septal defects, offering superior sensitivity compared to transthoracic imaging and providing en-face views of the septum 1, 2
• Assess for interatrial shunting using saline contrast echocardiography with Valsalva maneuver to detect right-to-left flow, which occurs in 70-75% of ASA cases 2
• Evaluate right heart chambers for evidence of right atrial and right ventricular enlargement, which indicates hemodynamically significant shunting 1
• Pulse oximetry at rest and during exercise to determine shunt direction and magnitude, particularly to identify exercise-induced desaturation 1
• Cardiac MRI or CT can quantify shunt magnitude (Qp:Qs ratio) and provide detailed anatomical assessment 1

Hemodynamic Assessment

Invasive catheterization is indicated when:

• Pulmonary artery pressures are elevated on echocardiography to directly measure pulmonary artery pressure, pulmonary vascular resistance, and confirm shunt magnitude 1
• Adult patients being considered for closure require precise hemodynamic data, especially if there is concern for pulmonary hypertension 1
• Calculate Qp:Qs ratio to confirm hemodynamically significant shunting (≥1.5:1) 1

Indications for Closure

Class I (Recommended) - Proceed with closure if:

• Symptomatic patients with impaired functional capacity AND right atrial/RV enlargement AND Qp:Qs ≥1.5:1 without cyanosis at rest or exercise, provided PA systolic pressure <50% systemic and PVR <1/3 systemic 1
• Paradoxical embolism has occurred, regardless of symptoms 1
• Documented orthodeoxia-platypnea syndrome is present 1

Class IIa (Reasonable) - Consider closure if:

• Asymptomatic patients with right atrial and RV enlargement AND Qp:Qs ≥1.5:1 without cyanosis, meeting the same pressure criteria as above 1
• Concomitant cardiac surgery is planned for another indication and hemodynamically significant shunting is present 1

Class IIb (May be considered) - Individualized decision if:

• Borderline pulmonary pressures exist (PA systolic pressure 50% or more of systemic and/or PVR >1/3 systemic) with net left-to-right shunt 1
• These patients require consultation with pulmonary hypertension specialists and may benefit from test occlusion or vasodilator responsiveness testing 1

Contraindications to Closure (Class III - Harm)

Do NOT close if:

• PA systolic pressure >2/3 systemic OR PVR >2/3 systemic OR net right-to-left shunt is present 1
• Severe irreversible pulmonary arterial hypertension (Eisenmenger physiology) without evidence of left-to-right shunt 1

Closure Method Selection

Percutaneous device closure is preferred when:

• Secundum-type defects with adequate rims for device placement are present 1
• However, ASA with large septal aneurysm or multifenestrated septum requires careful evaluation by interventional cardiologists before device closure, as anatomy may not be suitable 1

Surgical closure is required for:

• Sinus venosus, coronary sinus, or primum defects, which are not amenable to device closure 1
• Unsuitable anatomy for percutaneous approach 1
• Concomitant cardiac procedures requiring surgical intervention 1

Post-Closure Follow-Up

Mandatory surveillance includes:

• Clinical evaluation at 3 months to 1 year post-device closure for device migration, erosion (which may present with chest pain or syncope), thrombus formation, or pericardial effusion 1
• Annual follow-up if closure was performed in adulthood and any of the following persist: pulmonary hypertension, atrial arrhythmias, RV or LV dysfunction, or coexisting valvular lesions 1
• Echocardiographic assessment for residual shunting, device position, and complications 1
• ECG surveillance for new or recurrent atrial arrhythmias 1

Critical Pitfalls to Avoid

Common errors in management:

• Closing defects in patients with established Eisenmenger syndrome leads to clinical deterioration and is contraindicated 1
• Underestimating pulmonary pressures on echocardiography alone—always confirm with catheterization when pressures appear elevated 1
• Missing device erosion complications in early post-procedure period—maintain high suspicion for chest pain or syncope up to several weeks after closure 1
• Assuming all ASAs require closure—small defects (<5mm) without RV volume overload do not impact natural history unless paradoxical embolism occurs 1
• Overlooking associated anomalies such as anomalous pulmonary venous connections, which require identification before closure planning 1

Special Considerations

Atrial septal aneurysm-specific concerns:

• ASA is associated with increased risk of paradoxical embolism through right-to-left shunting, particularly during Valsalva or conditions that transiently increase right atrial pressure 2, 3
• Anticoagulation decisions for ASA with patent foramen ovale and cryptogenic stroke should follow stroke prevention guidelines, with closure being reasonable for secondary prevention 1
• ASA can cause bidirectional shunting depending on respiratory cycle and relative atrial pressures, making hemodynamic assessment more complex 4, 5