What are the indications and management strategies for left atrial appendage closure in patients with atrial fibrillation?

Left Atrial Appendage Closure in Atrial Fibrillation

Left atrial appendage closure (LAAC) is primarily indicated for patients with atrial fibrillation who have contraindications to long-term oral anticoagulation therapy, and should not be used simply as an alternative to anticoagulation in patients who can tolerate it. 1

Indications for LAAC

Primary Indications

• Patients with AF at high risk for stroke (CHA₂DS₂-VASc score ≥2) who have:
  • Contraindications to long-term oral anticoagulation therapy 1
  • History of life-threatening bleeding while on anticoagulation
  • Recurrent falls or high fall risk with significant bleeding consequences

Secondary Indications

• As an adjunct procedure during:
  • Cardiac surgery in patients with AF 1
  • Endoscopic or hybrid AF ablation 1
  • Stand-alone endoscopic surgical closure in patients with contraindications to anticoagulation 1

Types of LAAC Procedures

1. Surgical LAAC:

   • Performed during open heart surgery
   • Techniques include excision, suturing, or stapling
   • Recommended as Class I (Level B) for patients with AF undergoing cardiac surgery 1
   • Should be considered (Class IIa, Level C) as an adjunct to oral anticoagulation in patients undergoing endoscopic or hybrid AF ablation 1

2. Percutaneous LAAC:

   • Minimally invasive catheter-based approach
   • Devices include WATCHMAN and Amplatzer Cardiac Plug
   • May be considered (Class IIb) in patients with high stroke risk and contraindications for long-term oral anticoagulation 1
   • Not indicated simply as an alternative to oral anticoagulation therapy 1

Procedural Considerations

Pre-procedure Assessment

• Comprehensive thromboembolic risk assessment (CHA₂DS₂-VASc score)
• Bleeding risk assessment (HAS-BLED score)
• Transesophageal echocardiography (TEE) to rule out LAA thrombus
• Assessment of LAA anatomy for device sizing

Procedure Details

• Typically performed under general anesthesia
• Guided by fluoroscopy and TEE (often 3D)
• Transseptal puncture to access left atrium
• Device deployment in LAA

Post-procedure Management

• Antithrombotic regimen typically includes:
  • Short-term oral anticoagulation (45 days) followed by
  • Dual antiplatelet therapy (6 months) followed by
  • Long-term aspirin monotherapy 1
• Follow-up TEE at 45 days to confirm adequate LAA closure 2

Efficacy and Safety Considerations

Efficacy

• LAAC can reduce stroke risk in appropriate patients
• The PROTECT AF trial showed non-inferiority of WATCHMAN device compared to warfarin for the composite endpoint of stroke, cardiovascular death, and systemic embolism 1

Safety Concerns and Complications

• Procedural complications include:
  • Pericardial effusion/cardiac tamponade
  • Device embolization
  • Air embolism
  • Catheter-related thrombus formation 3
• Device-related thrombus can occur in 1.7%-7.2% of cases 1
• Peri-device leaks (0-5mm) occur in approximately 25% of cases 1

Important Caveats

1. Residual Stroke Risk: Patients with previous OAC failure (stroke/TIA while on anticoagulation) may have high residual stroke risk after LAAC (only 14% reduction from predicted rate vs. 77% in those with OAC contraindications) 4

2. Learning Curve Effect: Complication rates decrease with operator experience, as demonstrated in the Continued Access to PROTECT AF registry 1

3. Need for Follow-up Imaging: Regular imaging is required to detect device-related thrombi, which can occur as late as 1 year post-implantation 1

4. Not All Strokes Are LAA-Related: The LAA is not the only source of thrombi in AF patients, suggesting potential need for continued antithrombotic therapy in some patients even after LAAC 1

Clinical Decision Algorithm

1. Assess stroke risk using CHA₂DS₂-VASc score

   • If score ≥2 in men or ≥3 in women → anticoagulation recommended

2. Evaluate for anticoagulation contraindications or failures:

   • History of life-threatening bleeding on anticoagulation
   • High fall risk with significant bleeding consequences
   • Recurrent stroke/TIA despite adequate anticoagulation
   • Inability to maintain therapeutic anticoagulation levels

3. If contraindications exist:

   • Consider LAAC as alternative stroke prevention strategy
   • For patients undergoing cardiac surgery → surgical LAAC
   • For patients not undergoing surgery → percutaneous LAAC

4. Post-LAAC antithrombotic regimen:

   • Standard approach: OAC (45 days) → DAPT (6 months) → ASA (indefinitely)
   • For patients with prior OAC failure and low bleeding risk: Consider extended DAPT or continued OAC due to high residual stroke risk 4

5. Follow-up protocol:

   • TEE at 45 days to confirm device position and LAA closure
   • Regular imaging to detect device-related thrombus
   • Continued monitoring for stroke symptoms

The decision to perform LAAC must carefully balance the risks of the procedure against the benefits of stroke prevention, particularly in patients who cannot tolerate long-term anticoagulation.