What are the Left Atrial Appendage (LAA) ligation and maze procedure, their indications, and why are they performed?

Left Atrial Appendage (LAA) Ligation and Maze Procedure: Indications and Clinical Applications

The LAA ligation and maze procedure are surgical interventions primarily performed to reduce stroke risk in patients with atrial fibrillation (AF), with LAA ligation targeting thrombus formation in the appendage and the maze procedure aiming to restore normal sinus rhythm.

Left Atrial Appendage (LAA) Ligation

What Is LAA Ligation?

• A surgical procedure that involves closing off or removing the left atrial appendage, a small, ear-shaped sac in the muscle wall of the left atrium
• Can be performed through:
  • Surgical excision/amputation (complete removal)
  • Surgical ligation (tying off with sutures)
  • Occlusion using specialized devices

Why LAA Ligation Is Performed

• The LAA is the source of >90% of thrombi in patients with non-valvular AF 1
• LAA ligation reduces the risk of thromboembolic events, particularly stroke, in patients with AF 2
• Provides an alternative stroke prevention strategy for patients who cannot tolerate long-term oral anticoagulation

Indications for LAA Ligation

1. Primary indication: Patients with AF or atrial flutter who are undergoing valve surgery 2
2. Patients with AF at high risk of stroke who have absolute contraindications for oral anticoagulation therapy 2
3. As an adjunct to surgical ablation procedures for AF 2

Important Considerations for LAA Ligation

• Despite LAA ligation, anticoagulation therapy is still recommended for at least 3 months after the procedure 2
• LAA ligation/excision should NOT be performed in patients without atrial arrhythmias who are undergoing valvular surgery (Class 3: Harm) 2
• Incomplete LAA occlusion can occur in up to 60% of cases with some surgical techniques 2
• LAA ligation alone does not eliminate the need for anticoagulation in most patients 2

Maze Procedure

What Is the Maze Procedure?

• A surgical procedure designed to treat AF by creating a pattern of scar tissue (maze) in the atria
• The original "cut-and-sew" technique has evolved to include various energy sources (cryoenergy, radiofrequency) to create lesions
• Creates a controlled pathway for electrical signals, preventing the chaotic electrical activity that causes AF

Components of the Full Maze Procedure 2

• Bi-atrial lesion set that includes:
  • Encircling lesions around all pulmonary veins
  • Incision/lesion to the mitral annulus
  • Lesion to the stump of ligated/amputated LAA
  • Right atrial lesions extending from superior to inferior vena cava
  • Lesions across right atrial appendage to tricuspid annulus

Why the Maze Procedure Is Performed

• To restore normal sinus rhythm in patients with symptomatic AF
• To reduce AF-related symptoms
• To potentially reduce stroke risk when combined with LAA ligation

Indications for the Maze Procedure

1. Primary indication: Symptomatic patients with paroxysmal or persistent AF who are undergoing valvular surgery 2
2. Patients with recurrent AF who are undergoing surgical correction of mitral regurgitation 2
3. Patients with AF that is symptomatic or associated with a history of embolism despite anticoagulation 2

Efficacy of the Maze Procedure

• Success rates range from 75% to 95% for freedom from AF at 1 year (versus 10% to 40% without ablation) 2
• More effective than catheter ablation for AF in patients with rheumatic mitral valve disease (82% versus 55% conversion to sinus rhythm) 2
• Less extensive procedures (pulmonary vein isolation or left-sided-only maze) are less successful than the full maze procedure 2

Combined Approach and Outcomes

Benefits of Combined LAA Ligation and Maze Procedure

• Addresses both mechanisms of stroke risk in AF: abnormal rhythm and LAA thrombus formation
• The LAAOS III trial demonstrated a 33% reduction in stroke risk when LAAO was performed during cardiac surgery 3
• Dramatic decrease in stroke risk has been observed in long-term follow-up studies 4

Potential Complications

• Longer procedure times
• Higher risk of operative complications
• Increased risk of permanent pacemaker implantation 2
• Incomplete LAA occlusion (up to 20% with some techniques) 2
• Thrombus formation on LAA occlusion devices (up to 7.2% per year) 2

Post-Procedure Management

• Anticoagulation for at least 3 months after the procedure is recommended 2
• Long-term anticoagulation decisions should be based on:
  • Evaluation of arrhythmia recurrence
  • Patient's CHA₂DS₂-VASc score
  • Bleeding risk factors

Clinical Decision Algorithm

1. For patients with AF undergoing valve surgery:

   • Discuss benefits/risks of adjunctive AF procedure
   • If symptomatic AF: Perform surgical pulmonary vein isolation or maze procedure
   • Add LAA ligation/excision to reduce thromboembolic risk
   • Provide anticoagulation for at least 3 months post-procedure

2. For patients with AF not undergoing other cardiac surgery:

   • If high stroke risk with contraindication to anticoagulation: Consider standalone LAA occlusion
   • If symptomatic AF despite medical therapy: Consider catheter ablation or surgical maze based on patient factors

3. For patients without AF undergoing valve surgery:

   • Do NOT perform LAA ligation/excision (potentially harmful)

The evidence strongly supports using these procedures in appropriate patients to reduce stroke risk and improve quality of life, but patient selection and proper technique are critical to achieving optimal outcomes.