Use of mechanical devices to reduce stroke in atrial fibrillation

Abstract

Atrial fibrillation is common, and its incidence is increasing. The preponderance of strokes occurring in non-valvular atrial fibrillation is attributable to thromboembolism from clot formed within the left atrial appendage (LAA). Current standard of care involves long-term oral anticoagulation to decrease the risk of clot formation; however, this strategy is complicated by a narrow therapeutic window with a significant incidence of bleeding complications. Early evidence suggests that surgical obliteration of the left atrial appendage reduces stroke risk, and more recently several percutaneous approaches to left atrial appendage treatment have been developed aimed at eliminating the appendage cavity to reduce stroke risk through plugging or ligation. The most studied device, the Watchman device (Boston Scientific, Marlborough, MA), has been shown to be non-inferior to adjusted-dose warfarin in non-valvular atrial fibrillation at reducing the risk of stroke. Unanswered questions surround optimal patient selection criteria for device occlusion of the left atrial appendage and comparison with novel oral anticoagulants. Moreover, multiple devices are in development and early stages of evaluation. Device-based occlusion of the left atrial appendage is a promising alternative to long-term oral anticoagulation to reduce stroke risk in patients with non-valvular atrial fibrillation.This chapter describes the role of the left atrial appendage in cardioembolic stroke in patients with atrial fibrillation and the basis of appendage closure to reduce stroke risk. We review the procedurally relevant anatomy of the left atrial appendage and discuss the surgical and percutaneous approaches and devices used to close the left atrial appendage.