What is a left atrial appendage (LAA) clip and what are the potential drawbacks of this procedure during open heart surgery?

Left Atrial Appendage Clip During Open Heart Surgery: Purpose and Potential Drawbacks

What is a Left Atrial Appendage (LAA) Clip?

A left atrial appendage clip is a surgical device applied during open heart surgery to occlude the left atrial appendage, primarily to reduce stroke risk in patients with atrial fibrillation by eliminating this common source of thrombus formation. 1

• The LAA is considered the main site of thrombus formation in patients with atrial fibrillation, responsible for approximately 90% of cardioembolic strokes in non-valvular AF 1
• Surgical LAA closure is recommended as an adjunct to oral anticoagulation in patients with AF undergoing cardiac surgery to prevent ischemic stroke and thromboembolism (Class I, Level B recommendation) 2
• The AtriClip is a commonly used epicardial clip device that is applied externally to the base of the LAA during cardiac surgery, completely excluding it from circulation 3, 4

Clinical Benefits of LAA Clipping

• In the LAAOS III trial, surgical LAA occlusion during cardiac surgery reduced the risk of ischemic stroke or systemic embolism (4.8% vs 7.0% in the control group) with a hazard ratio of 0.67 2
• Studies have shown high success rates (95-100%) for LAA exclusion with clip devices during open cardiac surgery 3, 5
• Long-term follow-up has demonstrated durability of LAA occlusion with the AtriClip device with no signs of reperfusion or significant LAA stumps up to 8 years post-implantation 4

Potential Drawbacks and Complications

Procedural Risks

• Major bleeding can occur during surgical manipulation of the LAA 2
• Damage to the circumflex coronary artery is a risk due to its proximity to the base of the LAA 2
• Incomplete occlusion remains a significant concern, with some surgical techniques showing success rates as low as 23% for suture exclusion and 0% for stapling 2

Post-Procedural Concerns

• Device-related thrombus formation can occur with an incidence of 1.7%-7.2% and is associated with higher risk of ischemic stroke 2, 6
• Peri-device leaks (0-5 mm) are present in approximately 25% of cases after LAA closure 2, 1
• Incomplete LAA occlusion can lead to a paradoxical increase in stroke risk, as thrombus has been identified in approximately 25% of patients with unsuccessful LAA occlusion 2

Anticoagulation Considerations

• LAA occlusion does not eliminate the need for anticoagulation in many patients, as the LAA is not the only left atrial region where thrombi can originate 2
• The LAAOS III trial showed benefit when LAA occlusion was added to anticoagulation, not as a replacement for it 2
• Post-procedure antithrombotic treatment may still expose patients to bleeding risks that could be equivalent to those of direct oral anticoagulants 2

Clinical Application Considerations

• Surgical LAA exclusion techniques show variable success rates depending on the technique used: excision (73% success), suture exclusion (23%), and stapling (0%) 2
• The variable anatomy of the LAA can make consistent and complete occlusion technically challenging 2
• Despite high technical success rates with modern clip devices (96-100%), follow-up imaging is essential to confirm complete closure 3, 7
• The procedure should be performed by experienced operators to minimize complications and ensure complete occlusion 6, 7

Conclusion on Clinical Utility

• LAA clipping during open heart surgery is most beneficial for patients with atrial fibrillation who are already undergoing cardiac surgery for other indications 2
• The procedure should be considered an adjunct to, rather than a replacement for, anticoagulation therapy in most patients 2
• Long-term studies have shown promising results for stroke prevention, with a relative risk reduction of up to 87.5% in selected patients 4