Nonpharmacologic therapy to prevent embolization in patients with atrial fibrillation
- Ziyad M Hijazi, MD, MPH, FAAP, FACC, MSCAI, FAHA
Ziyad M Hijazi, MD, MPH, FAAP, FACC, MSCAI, FAHA
- Professor of Pediatrics, Weill Cornell Medicine
- Chairman, Department of Pediatrics & Director, Cardiac Program
- Sidra Medical & Research Center
- Doha, Qatar
- Jacqueline Saw, MD, FRCPC, FACC
Jacqueline Saw, MD, FRCPC, FACC
- Clinical Associate Professor
- University of British Columbia
- Vancouver General Hospital
Most patients with atrial fibrillation should receive anticoagulant therapy to reduce the risk of systemic embolization. However, there are varying degrees of bleeding risk associated with anticoagulation and not all individuals are candidates for this therapy . (See "Warfarin and other VKAs: Dosing and adverse effects" and "Risk of intracerebral bleeding in patients treated with anticoagulants".)
The optimal approach to reducing the risk of embolization in patients for whom long-term anticoagulation is indicated but who are unable to take it is not clear. Some nonpharmacologic strategies to prevent recurrent atrial fibrillation, such as radiofrequency catheter ablation, have not been proven to reduce the risk of embolic stroke. (See "Catheter ablation to prevent recurrent atrial fibrillation: Clinical applications".)
The left atrial appendage (LAA) is the usual source for clot that embolizes. (See 'Rationale' below.) Percutaneous approaches, often referred to as LAA exclusion procedures, that mechanically prevent embolization of LAA thrombi have been developed and tested and are discussed in this topic. In addition, some patients undergoing cardiac surgery for reasons such as valve replacement or repair or coronary artery bypass graft surgery are candidates for LAA exclusion at the time of surgery. (See 'Patients undergoing cardiac surgery' below.)
Among patients with nonvalvular atrial fibrillation (AF), the vast majority of thrombus material is located within or involves the left atrial appendage (LAA). The intense fibrosis and inflammation seen in the left atrium of patients with AF, which are likely predisposing factors to thrombus formation, are particularly intense in the LAA. In addition, the fibrillating LAA is the only area within the left atrium that is comprised of pectinate muscle and can create an appropriate milieu for blood stasis and thrombus formation. It is estimated that 90 percent of left atrial thrombi are located in the LAA . (See "Atrial fibrillation: Anticoagulant therapy to prevent embolization", section on 'Decide on anticoagulation'.)
The importance of the LAA in thromboembolic risk among patients with AF provides the rationale for ligation, amputation, or occlusion of the LAA, especially in patients who are candidates for but cannot receive oral anticoagulation, or those at high risk of bleeding with oral anticoagulation.
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