Left Atrial Appendage Closure: Purpose and Applications
Left atrial appendage closure (LAAC) is a procedure to seal off the left atrial appendage to prevent stroke in patients with atrial fibrillation who have contraindications to oral anticoagulation therapy. This intervention addresses the fact that over 90% of thrombi in non-valvular atrial fibrillation form in the left atrial appendage 1.
What is the Left Atrial Appendage?
The left atrial appendage (LAA) is a small, ear-shaped pouch connected to the left atrium of the heart. In patients with atrial fibrillation:
- It becomes a site of blood stasis
- This stagnant blood can form clots
- These clots may dislodge and travel to the brain, causing stroke
Types of LAA Closure
1. Surgical LAA Closure
- Performed during cardiac surgery
- Recommended as an adjunct to oral anticoagulation in patients with AF undergoing cardiac surgery (Class I, Level B) 2
- Can be performed during endoscopic or hybrid AF ablation (Class IIa, Level C) 2, 3
- Techniques include:
- Complete excision (preferred when feasible)
- Closure with double-layer suturing
- Use of dedicated LAA occlusion devices
2. Percutaneous LAA Occlusion
- Minimally invasive catheter-based procedure
- Performed via transseptal puncture under fluoroscopic and echocardiographic guidance 4
- Common devices:
- WATCHMAN and WATCHMAN FLX (Boston Scientific)
- AMPLATZER Cardiac Plug and Amulet (St. Jude Medical) 4
Primary Indications
LAAC is primarily indicated for:
Patients with AF at high risk of stroke (CHA₂DS₂-VASc score ≥2 in women, ≥1 in men) who have contraindications to long-term oral anticoagulation 2, 1
- Severe bleeding or anemia
- High bleeding risk
- Labile INR
- Recurrent embolic events despite anticoagulation
As an adjunct to oral anticoagulation in patients with AF undergoing cardiac surgery 2, 3
Procedural Considerations
The procedure is technically demanding due to:
- Anatomic variability of the appendage
- Fragility of the appendage tissue
- Need for precise device sizing and placement
Key procedural elements include:
- General anesthesia
- Guidance by fluoroscopy and transesophageal echocardiography (TEE) or intracardiac echocardiography (ICE) 5
- Careful material manipulation
- Adequate operator training
Post-Procedure Management
After LAAC, antithrombotic therapy typically follows this regimen:
- 45 days of oral anticoagulation plus aspirin
- 6 months of dual antiplatelet therapy
- Long-term aspirin monotherapy 2, 3
However, emerging evidence suggests minimal antithrombotic therapy may be sufficient in very high bleeding risk patients 2.
Efficacy and Complications
Efficacy:
- LAAOS III trial: 33% reduction in stroke risk with LAAC during cardiac surgery 3
- PROTECT AF trial: Non-inferiority of WATCHMAN device compared to warfarin 3
Potential Complications:
- Device-related thrombus (1.7%-7.2% of cases)
- Peri-device leaks (approximately 25% of cases)
- Stroke
- Major bleeding
- Pericardial effusion
- Vascular complications 2
Follow-up Protocol
Regular monitoring is essential:
- TEE at 45 days to confirm device position and LAA closure
- Ongoing imaging to detect device-related thrombi (which can occur up to 1 year post-implantation)
- Continued monitoring for stroke symptoms 2, 3
Institutional Requirements
The 2016 SCAI/ACC/HRS guidelines emphasize that LAAC should be performed in centers with:
- Multidisciplinary teams including electrophysiologists, interventional cardiologists, imaging specialists, and others
- Adequate procedural volume to maintain proficiency
- Comprehensive patient-centered care approach 2
LAAC represents an important alternative to oral anticoagulation for stroke prevention in carefully selected patients with atrial fibrillation, particularly those with contraindications to long-term anticoagulation therapy.