What is Left Atrial Appendage (LAA) ligation?

Left Atrial Appendage (LAA) Ligation: Definition and Clinical Applications

Left atrial appendage (LAA) ligation is a surgical or percutaneous procedure that closes off the LAA to prevent thrombus formation and reduce stroke risk in patients with atrial fibrillation, particularly those who cannot tolerate long-term anticoagulation therapy. 1

Anatomical and Procedural Considerations

The LAA is a small, ear-shaped muscular pouch connected to the left atrium of the heart. In patients with atrial fibrillation, this structure is the source of thrombi in approximately 90% of cases, making it a critical target for stroke prevention strategies.

Techniques for LAA Ligation

LAA ligation can be performed using several approaches:

1. Surgical techniques (during cardiac surgery):

   • Excision - Complete surgical removal of the LAA (73% success rate)
   • Suture exclusion - Oversewing the base without excision (23% success rate)
   • Stapling and excision - Using surgical staples to close the LAA before removal (lower success rates)
   • Epicardial clip application - Using devices like the Gillinov-Cosgrove clip LAA exclusion system 1

2. Percutaneous techniques:

   • Endocardial occlusion devices - Placement of devices like WATCHMAN through a transseptal approach
   • Epicardial ligation - Using devices like the LARIAT snare device for closed-chest ligation 2
   • Combined approaches - Hybrid procedures that may include catheter ablation with LAA closure 3

Efficacy and Success Rates

The success of LAA ligation varies significantly by technique:

• Surgical excision: Highest success rate at 73%
• Suture exclusion: Lower success rate at 23%
• Stapling alone: Very low success rates (near 0%) 1

Incomplete closure is a significant concern, with echocardiographic follow-up suggesting incomplete occlusion in approximately 50% of surgical cases. This is particularly concerning as thrombus has been identified in about 25% of patients with unsuccessful LAA occlusion. 1

Clinical Indications

LAA ligation is primarily indicated for:

1. Patients with atrial fibrillation undergoing cardiac surgery (Class IIb recommendation) 1, 4
2. Patients with contraindications to long-term oral anticoagulation who remain at high stroke risk 1, 4
3. As an adjunct to oral anticoagulation in patients undergoing endoscopic or hybrid AF ablation (Class IIa recommendation) 1, 4

Post-Procedure Management

• Anticoagulation: Typically required for at least 45 days post-procedure, followed by dual antiplatelet therapy for 6 months, then long-term aspirin monotherapy 4
• Imaging follow-up: Transesophageal echocardiography (TEE) is essential to confirm successful closure and monitor for complications 1, 4

Complications and Pitfalls

• Incomplete closure: Occurs in approximately 50% of surgical cases 1
• Device-related thrombus: Occurs in 1.7-7.2% of cases, can appear as late as 1 year post-implantation 1, 4
• Peri-device leaks: Present in approximately 25% of cases 1
• Procedural complications: Include cardiac tamponade, pericardial effusion, and vascular complications 1, 3

Important Considerations for Clinical Practice

1. Continued anticoagulation may be necessary after surgical LAA ligation due to high rates of incomplete closure 1
2. Institutional experience matters - Complication rates are significantly higher in centers performing fewer procedures (9.5% in centers with 5-15 cases/year vs. 5.6% in centers with 32-211 cases/year) 1
3. Multidisciplinary approach is essential - LAA occlusion programs should involve collaboration between electrophysiologists, interventional cardiologists, imaging specialists, and cardiac surgeons 1
4. Regular imaging follow-up is critical to detect late complications such as device-related thrombus 1, 4

LAA ligation represents an important alternative for stroke prevention in patients with atrial fibrillation, particularly when long-term anticoagulation is contraindicated or problematic. However, the variable success rates and potential complications underscore the importance of proper patient selection, procedural expertise, and diligent follow-up.