What is left atrial appendage (LAA) ligation and when is it indicated for adults with non‑valvular atrial fibrillation at moderate‑to‑high stroke risk who cannot tolerate anticoagulation?

What is Left Atrial Appendage (LAA) Ligation?

LAA ligation is a surgical or percutaneous procedure that mechanically closes off the left atrial appendage—the primary site of thrombus formation in atrial fibrillation—using sutures, clips, or devices to prevent stroke in patients who cannot tolerate long-term anticoagulation. 1

Anatomic Rationale

• The left atrial appendage is responsible for approximately 90% of cardioembolic strokes in non-valvular atrial fibrillation, making it the critical therapeutic target for stroke prevention 2
• Thrombus formation occurs in the LAA due to blood stasis during atrial fibrillation, particularly in patients with LAA size >34 cm³, cauliflower morphology, or low-velocity flow 2

Types of LAA Ligation Techniques

Surgical Approaches (During Open Heart Surgery)

• Excision technique: Complete removal of the LAA with oversewing of the base—achieves 73% success rate 1, 3
• Suture exclusion: Oversewing the LAA base without excision—achieves only 23% success rate 1, 3
• Surgical stapling: Mechanical stapling of the LAA—achieves 0% success rate and should be avoided 1, 3
• Atrial clip devices (e.g., Gillinov-Cosgrove clip): Mechanical clip closure achieving >90% complete occlusion with no device-related adverse events 1, 3

Percutaneous Approaches

• LARIAT device: Uses an epicardial snare via combined endo-epicardial approach to place a suture around the LAA base, achieving 90-99% acute closure but with 20% incomplete occlusion in inexperienced operators 1, 4, 5
• WATCHMAN device: Endocardial plug device (not technically "ligation" but occlusion) requiring dual antiplatelet therapy for 6 weeks post-procedure 1

Clinical Indications Based on Guidelines

Strong Recommendation (Class I)

• Surgical LAA closure during concomitant cardiac surgery in patients with atrial fibrillation as adjunctive therapy to anticoagulation—reduces stroke risk by 33% (HR 0.67) based on LAAOS III trial 2, 3

Weak Recommendation (Class IIb)

• Percutaneous LAA occlusion only for patients with absolute contraindications to long-term oral anticoagulation who are at high stroke risk 1, 3
• The 2018 CHEST guidelines suggest LAA occlusion for high-risk patients with absolute contraindications to anticoagulation (weak recommendation, low quality evidence) 1

Critical Clinical Pitfalls

Incomplete Occlusion is Dangerous

• Incomplete LAA occlusion occurs in 50-60% of surgical attempts overall and paradoxically increases stroke risk due to thrombus formation in the residual LAA stump 1, 3
• Thrombus is identified in approximately 25% of patients with unsuccessful LAA occlusion, particularly with suture exclusion or stapled remnants 1
• All patients must continue anticoagulation after attempted surgical LAA closure unless complete occlusion is confirmed by transesophageal echocardiography 3

Device-Related Complications

• LARIAT device has 11.5% periprocedural adverse event rate, including cardiac perforation, pericarditis, and procedure-related stroke 4, 5
• Incomplete occlusion with LARIAT occurs in 10-20% of cases, with leaks of 2-4 mm detected at 30-45 day follow-up 4, 6, 5
• Device-related thrombus formation occurs in 1.7-7.2% per year and is associated with increased ischemic stroke risk 1, 2

Anticoagulation Cannot Be Eliminated

• LAA ligation does not eliminate the need for anticoagulation in most patients because the LAA is not the only left atrial region where thrombi can originate 2, 3
• The LAAOS III trial showed benefit when LAA occlusion was added to anticoagulation (77% of patients continued anticoagulation), not as a replacement for it 2, 3
• Post-procedure antithrombotic treatment (dual antiplatelet therapy for WATCHMAN, aspirin for LARIAT) still exposes patients to bleeding risks potentially equivalent to direct oral anticoagulants 1, 2

No Comparison with Modern Anticoagulation

• No randomized trials compare LAA occlusion devices with direct oral anticoagulants (NOACs)—only with warfarin, which is no longer standard of care 1, 3
• This represents a critical evidence gap since NOACs are safer and more effective than warfarin 3

When LAA Ligation is Appropriate

For patients already undergoing cardiac surgery for other indications: Add surgical LAA closure (preferably excision or clip) as adjunctive therapy to anticoagulation 1, 2, 3

For patients with true absolute contraindications to anticoagulation: Consider percutaneous LAA occlusion only after exhausting all anticoagulation options, including NOACs 1, 3

Never appropriate: As an elective alternative to anticoagulation in patients who can tolerate oral anticoagulation 3

Verification of Successful Closure

• Transesophageal echocardiography at 30-45 days post-procedure is mandatory to confirm complete occlusion 4, 5
• Complete closure is defined as no color Doppler flow from the left atrium into the appendage and no residual stump >1.0 cm 1
• Incomplete closure requires continuation or resumption of anticoagulation 1, 3