What is the perioperative stroke risk for an adult patient with a history of atrial fibrillation and mitral valve disease undergoing a combined maze procedure, left auricle excision, and mitral valve repair?

Perioperative Stroke Risk with Combined Maze, Left Atrial Appendage Excision, and Mitral Valve Repair

The perioperative stroke risk for combined maze procedure, left atrial appendage excision, and mitral valve repair is approximately 0-2% based on contemporary series, with no documented increase in perioperative morbidity or mortality when the maze procedure is added to mitral valve surgery. 1, 2, 3

Quantified Stroke Risk Data

The combined endpoint of thromboembolic events is 0.25% per patient-year in patients undergoing mitral valve repair plus maze procedure, with freedom from stroke or anticoagulant-associated bleeding reaching 100% at 2 years. 4

• Multiple studies demonstrate that the maze procedure does not increase perioperative mortality or stroke risk when properly performed 1, 2
• In a series of 53 patients undergoing combined mitral valve surgery and maze III procedure, there were no hospital deaths and only 2 patients (5%) experienced minor cerebral infarction 3
• A larger series of 521 patients showed superior freedom from stroke in patients with successful maze procedures compared to failed procedures 5

Key Risk Factors That Increase Stroke Risk

Three specific factors predict failed maze procedures and higher stroke risk:

• Left atrium >70mm (hazard ratio 2.6 for maze failure) 5
• Preoperative atrial fibrillation duration >10 years (hazard ratio 8.2 for maze failure) 5
• F-wave voltage in V1 <0.1mV (hazard ratio 6.2 for maze failure) 5

Patients with these risk factors have 3-fold higher stroke rates (hazard ratio 3.0) compared to those with successful maze procedures 5.

Critical Perioperative Thrombogenic Mechanisms

The immediate postoperative period (first 40 hours) carries the highest stroke risk due to multiple prothrombotic factors:

• The maze procedure creates multiple surgical lesions that serve as thrombogenic surfaces in the immediate postoperative period 4, 6
• Incomplete left atrial appendage closure occurs in 26-57% of cases and directly increases thromboembolism risk 4, 6
• Air embolization during valve repair is a well-documented stroke mechanism, particularly with inadequate de-airing techniques 4, 7
• Blood stasis from loss of atrial contraction post-maze, combined with surgical trauma, creates a prothrombotic state 4
• 40% of strokes occur intraoperatively, with 60% occurring postoperatively, peaking at 40 hours after surgery 7

Mandatory Anticoagulation Protocol

All patients require warfarin with target INR 2.5-3.5 for at least 3 months postoperatively, regardless of rhythm status. 4, 6, 7

• This applies even if the maze procedure successfully converts the patient to sinus rhythm 6
• Patients with preoperative atrial fibrillation ≥3 months have 80% persistence of atrial fibrillation after surgery, necessitating prolonged anticoagulation 8, 6
• The maze procedure does not eliminate the need for anticoagulation in the immediate postoperative period 4, 7

Critical Diagnostic Pitfall to Avoid

Standard CT scans miss 58-100% of new brain lesions following cardiac valve procedures and have poor sensitivity for acute ischemic stroke within the first 6-24 hours. 4, 7

• Brain MRI with diffusion-weighted imaging (DWI) must be obtained immediately if any neurological symptoms develop 4, 7
• Do not attribute neurological deficits to "postoperative delirium" without excluding stroke with MRI 4
• CT angiography should be obtained immediately to identify large vessel occlusion, which occurs in 10.9% of post-cardiac surgery strokes 7

Procedural Complexity Considerations

Adding the maze procedure increases cardiopulmonary bypass time by approximately 24 minutes and aortic cross-clamp time by 27 minutes, but does not increase ICU stay, intubation period, or blood loss. 3

• Cardiopulmonary bypass times exceeding 2 hours and cross-clamp times beyond 120 minutes warrant consideration for conversion to simpler approaches 6
• The full biatrial maze procedure achieves 75-95% freedom from atrial fibrillation at 1 year versus 10-40% with limited procedures 6, 9

Long-Term Stroke Prevention Benefit

Successful maze procedures result in superior freedom from stroke compared to failed procedures (hazard ratio 3.0 for stroke in failed maze group). 5

• Freedom from atrial fibrillation recurrence is 98.4% at 5 years and 81.0% at 12 years in patients with successful maze procedures 5
• The maze procedure partially nullifies the advantage of mitral repair by potentially eliminating the need for long-term anticoagulation, but only if sinus rhythm is maintained 8