What are the guidelines for mitral valve repair and maze procedure with left atrial appendage (LAA) excision?

Guidelines for Mitral Valve Repair with Maze Procedure and Left Atrial Appendage Excision

Primary Recommendation for Concomitant Maze Procedure

For patients with symptomatic paroxysmal or persistent atrial fibrillation undergoing mitral valve repair, a concomitant surgical maze procedure or pulmonary vein isolation is beneficial to reduce symptoms and prevent recurrent arrhythmias, with success rates of 75-95% versus 10-40% without ablation. 1

Patient Selection Criteria

• Symptomatic AF patients: The maze procedure is most strongly indicated when AF causes symptoms or has resulted in prior thromboembolic events despite anticoagulation 1
• Duration considerations: AF duration ≥3 months predicts 80% persistence of AF after mitral valve surgery alone, making the maze procedure particularly valuable 1
• Left atrial size: Preoperative left atrial diameter >60 mm predicts maze failure, though the procedure should still be considered with aggressive atrial reduction 2
• Age and surgical risk: The decision must account for patient age and health status, as the maze adds procedural complexity and potential morbidity 1

Procedural Approach

The full biatrial maze procedure is superior to limited approaches (pulmonary vein isolation alone or left-sided only maze) for patients with persistent AF, though less extensive procedures may suffice for paroxysmal AF. 1

• Full maze achieves 75-95% freedom from AF at 1 year versus 10-40% with limited procedures 1
• When combined with mitral valve repair, the maze adds minimal complexity since the left atrium is already open 1
• The procedure does not increase operative mortality risk in properly selected patients 1
• Less extensive procedures are more appropriate for paroxysmal AF or when combined with non-mitral valve procedures 1

Left Atrial Appendage Management

For patients with AF or atrial flutter undergoing valve surgery, left atrial appendage ligation or excision is reasonable to reduce thromboembolic risk. 1

Critical Safety Warning

For patients WITHOUT atrial arrhythmias undergoing valvular surgery, left atrial appendage occlusion/exclusion/amputation is potentially harmful and should not be performed. 1

Technical Considerations

• LAA excision can be accomplished safely using staple closure techniques during mitral valve surgery 3
• Incomplete LAA closure occurs in 26-57% of cases and increases thromboembolism risk 4, 5
• The majority of thromboembolic events (71%) occur in patients who underwent mitral valve repair, emphasizing the importance of complete closure 6

Mandatory Postoperative Anticoagulation

All patients undergoing maze procedure and/or LAA excision require anticoagulation with warfarin (target INR 2.5-3.5) for at least 3 months postoperatively, regardless of rhythm status. 1, 4

Anticoagulation Rationale

• The maze procedure creates multiple surgical lesions that serve as thrombogenic surfaces in the immediate postoperative period 4
• Blood stasis from loss of atrial contraction post-maze, combined with surgical trauma, creates a prothrombotic state 4
• Patients not prescribed warfarin at discharge have significantly higher thromboembolic event rates (15% vs 10%) 6
• Even with successful maze, patients with preoperative AF ≥3 months have 80% persistence of AF requiring continued anticoagulation 1, 4

Expected Outcomes and Long-Term Results

Rhythm Outcomes

• Sinus rhythm restoration occurs in 81-86% of patients at 6 months 7, 8
• 15-year freedom from AF is 63%, with small-voltage f-wave being an independent predictor of recurrence 7
• Atrial contractility (A-wave on Doppler) returns in 68% of patients 8

Cardiac Function Benefits

• Postoperative left ventricular dimensions are significantly smaller in patients who restore sinus rhythm (48.6±4.6 mm vs 54.6±4.7 mm diastolic diameter) 8
• 15-year freedom from NYHA class ≥III heart failure is 79% 7
• Left ventricular diastolic diameter ≥65 mm is an independent risk factor for recurrent mitral regurgitation 7

Thromboembolic Risk Reduction

• Combined procedure achieves 0.25-0.79% per patient-year thromboembolic event rate 7, 8
• Freedom from stroke or anticoagulant-associated bleeding is 100% at 2 years in maze patients versus 90% in controls 4
• Seven of 11 thromboembolic events occur in patients with recurrent AF, emphasizing the importance of rhythm control 7

Operative Mortality and Morbidity

• Hospital mortality is 1-4.2% for combined procedures 7, 8, 2
• Reopening for bleeding occurs in 7% of cases 8
• 15-year actuarial survival is 71%, with event-free survival of 90% at 8 years 7, 8
• Patients maintaining sinus rhythm have significantly longer survival than those with recurrent AF 2

Critical Pitfalls to Avoid

Incomplete LAA Closure

• Residual peridevice leak occurs in 26-57% of cases and negates the protective benefit 4, 5
• Surgical technique must ensure complete exclusion with staple or suture closure 3

Inadequate Postoperative Anticoagulation

• The immediate postoperative period carries the highest thromboembolism risk due to inadequate anticoagulation, inflammatory state, and atrial stunning 4
• Never attribute neurological deficits to "postoperative delirium" without excluding stroke with brain MRI (not CT, which misses 58-100% of acute lesions) 4, 5

Procedural Time Management

• Cardiopulmonary bypass times exceeding 2 hours and cross-clamp times beyond 120 minutes warrant consideration for conversion to simpler approaches 9
• Full biatrial maze adds significant operative time; surgeons should gain proficiency with simpler procedures first 9

Left Atrial Size Reduction

• Postoperative left atrial diameter >50 mm predicts maze failure 2
• Aggressive atrial reduction to <50 mm improves success rates, particularly in patients with preoperative diameter >60 mm 2
• Posterolateral wall resection is superior to posterior wall reduction alone for large atria 2