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Catheter Ablation in Combination With Left Atrial Appendage Closure for Atrial Fibrillation
Published on: February 26, 2013
Left Atrial Appendage: Physiology, Pathology, and Role as a Therapeutic Target
Damiano Regazzoli1, Francesco Ancona1, Nicola Trevisi2
1Non-Invasive Cardiology, Cardio-Thoracic-Vascular Department, San Raffaele Scientific Institute, Via Olgettina 60, 20132 Milano, Italy.
Insights
Atrial fibrillation (AF) increases stroke risk, but oral anticoagulation is often underused. Left atrial appendage occlusion offers an alternative to prevent thromboembolism in AF patients.
Area of Science:
- Cardiology
- Vascular Medicine
Background:
- Atrial fibrillation (AF) is a common arrhythmia increasing thromboembolic risk, particularly ischemic stroke.
- Risk assessment scores (CHADS2, CHA2DS2-VASc) guide oral anticoagulation (OAC) but OAC is underutilized due to compliance issues and bleeding risks.
- The Virchow triad (endocardial dysfunction, stasis, altered hemostasis) explains thrombogenesis, especially in the left atrial appendage (LAA), a common site for thrombi in AF.
Purpose of the Study:
- To review the physiological and pathophysiological role of the left atrial appendage (LAA) in atrial fibrillation.
- To explore catheter-based methods for LAA occlusion as a strategy for thromboembolism prevention.
- To discuss the efficacy of LAA exclusion in reducing the need for oral anticoagulation.
Main Methods:
- Review of existing literature on atrial fibrillation, thromboembolism, and left atrial appendage function.
- Analysis of the pathophysiology of thrombus formation in the LAA during AF.
- Examination of current surgical and catheter-based LAA occlusion techniques.
Main Results:
- The LAA, due to its morphology and low flow, is a primary site for thrombus formation in 90% of nonvalvular AF patients.
- LAA occlusion effectively excludes the main source of emboli, potentially negating the need for OAC.
- Various catheter-based LAA exclusion methods have been developed and reviewed.
Conclusions:
- Left atrial appendage occlusion is a promising alternative for thromboembolism prevention in AF patients.
- Excluding the LAA can mitigate stroke risk without the complications associated with long-term oral anticoagulation.
- Catheter-based LAA occlusion represents an important advancement in managing AF-related stroke risk.
Abstract:
Atrial fibrillation (AF) is the most common clinically relevant cardiac arrhythmia. AF poses patients at increased risk of thromboembolism, in particular ischemic stroke. The CHADS2 and CHA2DS2-VASc scores are useful in the assessment of thromboembolic risk in nonvalvular AF and are utilized in decision-making about treatment with oral anticoagulation (OAC). However, OAC is underutilized due to poor patient compliance and contraindications, especially major bleedings. The Virchow triad synthesizes the pathogenesis of thrombogenesis in AF: endocardial dysfunction, abnormal blood stasis, and altered hemostasis. This is especially prominent in the left atrial appendage (LAA), where the low flow reaches its minimum. The LAA is the remnant of the embryonic left atrium, with a complex and variable morphology predisposing to stasis, especially during AF. In patients with nonvalvular AF, 90% of thrombi are located in the LAA. So, left atrial appendage occlusion could be an interesting and effective procedure in thromboembolism prevention in AF. After exclusion of LAA as an embolic source, the remaining risk of thromboembolism does not longer justify the use of oral anticoagulants. Various surgical and catheter-based methods have been developed to exclude the LAA. This paper reviews the physiological and pathophysiological role of the LAA and catheter-based methods of LAA exclusion.
