What is left atrial appendage exclusion using an atrial clip?

Left Atrial Appendage Exclusion Using an Atrial Clip

Left atrial appendage (LAA) exclusion using an atrial clip is a surgical technique performed during open cardiac surgery that mechanically closes off the LAA—the source of approximately 90% of embolic strokes in patients with atrial fibrillation—using an epicardial clipping device such as the AtriClip (Gillinov-Cosgrove clip system), which has FDA approval and achieves complete LAA occlusion in over 90% of cases. 1, 2, 3

Mechanism and Technique

The atrial clip is an epicardial device applied directly to the outside of the heart during cardiac surgery to mechanically exclude the LAA from the circulation. 1, 3

Key technical features include:

• The device is placed on the beating heart, either on or off cardiopulmonary bypass, at any point after sternotomy 3
• Available in multiple sizes (35,40,45, and 50 mm) to accommodate varying LAA anatomy 3
• Mean application time is approximately 4 minutes, making it a quick adjunctive procedure 4
• The clip achieves both mechanical occlusion and complete electrical isolation of the LAA within 18 minutes of placement 4

Clinical Efficacy and Success Rates

The atrial clip demonstrates superior success rates compared to traditional surgical LAA exclusion techniques. 1, 2, 3

• Procedural success rates range from 92-100% for complete LAA exclusion, confirmed by imaging 2, 3, 5
• This contrasts sharply with traditional surgical techniques: excision (73% success), suture exclusion (23%), and stapling (0%) 1, 6
• At 3-month follow-up, 98.4% of patients maintained complete LAA exclusion by imaging 3
• In minimally invasive cardiac surgery settings, complete exclusion was achieved in 92.2% of patients 5

Guideline-Based Indications

The 2024 European Society of Cardiology guidelines recommend surgical LAA closure as adjunctive therapy during concomitant cardiac surgery in patients with atrial fibrillation (Class I, Level B recommendation). 1, 6, 7

Appropriate patient populations include:

• Patients with atrial fibrillation undergoing cardiac surgery for other indications 1, 7
• Patients with history or suspicion of atrial arrhythmia 2
• Patients with CHADS2-VASc score greater than 2 3
• Patients with left ventricular dilatation or history of transient ischemic attacks 2

Stroke Prevention Benefit

The LAAOS III trial demonstrated that surgical LAA occlusion during cardiac surgery reduced ischemic stroke or systemic embolism from 7.0% to 4.8% over 3.8 years (hazard ratio 0.67,95% CI 0.53-0.85, P=0.001), representing a 33% reduction in stroke risk. 1, 6, 7

Critical consideration: This benefit occurred despite 77% of patients continuing oral anticoagulation, establishing LAA clip occlusion as an adjunct to—not a replacement for—anticoagulation therapy. 1, 6, 7

Safety Profile

The atrial clip demonstrates an excellent safety profile with no device-related adverse events or perioperative mortality in multiple studies. 2, 3

• No device-related complications at 30-day follow-up 3
• No late device-related complications on follow-up imaging 2
• No thromboembolic events during median follow-up of 19 months 5
• No damage to the circumflex coronary artery, a major concern with other surgical LAA exclusion techniques 1, 3

Critical Clinical Pitfalls

Incomplete LAA occlusion is the most dangerous complication of surgical LAA exclusion, occurring in approximately 50% of cases with traditional techniques, and is associated with paradoxically increased stroke risk due to thrombus formation in the residual LAA stump. 1, 6, 7

• Thrombus is identified in approximately 25% of patients with unsuccessful LAA occlusion using suture or stapling techniques 1, 6
• The atrial clip specifically addresses this problem with >90% complete occlusion rates 2, 3, 5
• Post-procedure imaging confirmation with transesophageal echocardiography or cardiac CT is mandatory to verify complete occlusion 3, 5

Anticoagulation must be continued after LAA clip placement unless complete occlusion is confirmed by imaging, as the LAA is not the only left atrial region where thrombi can originate. 6, 7

Post-Procedure Management

All patients require imaging confirmation of complete LAA exclusion at 3 months using either cardiac CT angiography or transesophageal echocardiography. 3, 5

• Complete exclusion is defined as distance from circumflex artery to device <10 mm without contrast leakage 5
• Patients should continue oral anticoagulation as indicated by their CHADS2-VASc score, as LAA occlusion is adjunctive therapy 1, 6, 7
• No specific device-related monitoring is required beyond standard post-cardiac surgery care 2, 8

Comparison to Percutaneous LAA Occlusion

The atrial clip is fundamentally different from percutaneous LAA occlusion devices (WATCHMAN, Amplatzer) in that it is applied surgically during open cardiac surgery, not via catheter-based intervention. 1

• Percutaneous devices are deployed via transseptal puncture and sit inside the LAA 1
• The atrial clip is applied epicardially from outside the heart during surgery 3, 4
• Percutaneous LAAO carries a Class IIb recommendation only for patients with absolute contraindications to anticoagulation 1, 6
• Surgical LAA clip occlusion during cardiac surgery carries a Class I recommendation as adjunctive therapy 1, 6