What is the appropriate management for a patient presenting with an aneurysmal septum?

Management of Aneurysmal Atrial Septum

An atrial septal aneurysm (ASA) with evidence of paradoxical embolism or documented thromboembolic events warrants closure (either percutaneously or surgically) combined with long-term anticoagulation, while isolated ASA without complications requires careful evaluation by interventional cardiology before deciding on device closure versus conservative management with anticoagulation.

Initial Risk Stratification and Evaluation

The primary concern with atrial septal aneurysm is its thromboembolic potential, particularly when associated with patent foramen ovale (PFO) or multiple fenestrations 1.

Key diagnostic considerations:

• Transesophageal echocardiography is superior to transthoracic imaging for detecting ASA, identifying multiple fenestrations, visualizing thrombus within the aneurysm, and detecting interatrial shunting (83% detection rate vs 41% with transthoracic approach) 2

• Membrane thickness ≥5 mm is a significant risk factor for cerebrovascular events, present in 75% of patients with stroke versus 27% without (p<0.05) 2

• Assess for associated defects: PFO is present in the majority of cases, and multiple fenestrations can exist within the redundant septum 2, 3

Indications for Closure

Class I (Definitive) Indications 1:

• Paradoxical embolism - documented or strongly suspected thromboembolic events (Level of Evidence: C)
• Documented orthodeoxia-platypnea (Level of Evidence: B)

Important caveat: ASA with large septal aneurysm or multifenestrated atrial septum requires careful evaluation and consultation with interventional cardiologists before device closure is selected 1. This is critical because the anatomy may not be suitable for standard percutaneous devices.

Management Algorithm

For ASA with Thromboembolic Events:

1. Immediate anticoagulation is mandatory when thrombus is present within the aneurysm or when embolic events have occurred 2

2. Closure should be performed (Class I indication for paradoxical embolism) 1

   • Percutaneous device closure is preferred when anatomically feasible
   • Single occluder devices can successfully close ASA with PFO and multiple fenestrations 3
   • Surgical closure is indicated when percutaneous approach is not feasible due to anatomy 1

3. Long-term anticoagulation is indicated in patients with ASA and history of embolic events, as the mechanism involves both primary thrombus formation within the aneurysm and paradoxical embolization through interatrial communications 2

For ASA without Complications:

Small defects (<5 mm) without RV volume overload do not require closure unless associated with paradoxical embolism 1

Larger defects with RV volume overload warrant closure to prevent long-term complications including atrial arrhythmias, reduced exercise tolerance, hemodynamically significant tricuspid regurgitation, and right-to-left shunting 1

Post-Closure Surveillance

Mandatory follow-up includes 1:

• Evaluation at 3 months to 1 year after device closure for possible device migration, erosion, or other complications (Class I, Level C)
• Echocardiographic surveillance at 24 hours, 1 month, 6 months, and 1 year, then at regular intervals for device position, residual shunting, thrombus formation, or pericardial effusion 1
• Device erosion (presenting with chest pain or syncope) warrants urgent evaluation (Class I, Level C) 1

Critical Pitfalls to Avoid

Do not rely solely on transthoracic echocardiography - transesophageal approach is essential for complete characterization and may be the only method to diagnose ASA in some patients 2

Do not assume all ASAs are suitable for percutaneous closure - large aneurysms and multifenestrated septa require expert interventional cardiology consultation before device selection 1

Do not overlook associated complications - ASA can be associated with mitral valve prolapse, and careful evaluation for other potential embolic sources is necessary 2

Recognize the high recurrence risk - patients with ASA and cerebrovascular events have a 67% rate of repeated cerebral events, emphasizing the importance of definitive treatment 2

Special Considerations

Annual clinical follow-up is recommended if closure was performed in adulthood and any of the following persist: pulmonary hypertension, atrial arrhythmias, RV or LV dysfunction, or coexisting valvular lesions (Class I, Level C) 1

Conservative management with anticoagulation alone may be considered in patients with high surgical/procedural risk, though this represents a compromise approach given the thromboembolic potential 4