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Heart Online First, published on December 17, 2014 as 10.1136/heartjnl-2014-306255 Review

Left atrial appendage occlusion Oluseun Alli, David Holmes Jr 1

The Division of Cardiovascular Diseases and Department of Internal Medicine, University of Alabama, Birmingham, Alabama, USA 2 The Division of Cardiovascular Diseases and Department of Internal Medicine, Mayo Clinic and Mayo Foundation, Rochester, Minnesota, USA Correspondence to Dr Oluseun Alli, Division of Cardiovascular Diseases, Department of Medicine, University of Alabama at Birmingham, 1720 2nd Avenue South, Birmingham, AL 35294, USA; [email protected] Received 2 September 2014 Revised 19 October 2014 Accepted 14 November 2014

ABSTRACT Left atrial appendage (LAA) occlusion for stroke and thromboembolism prevention in patients with atrial fibrillation (AF) represents a significant advancement in the field of cardiovascular disease. Prevention and avoidance of the devastating consequences of thromboembolic complications from AF continues to be central in the management of these patients. The role of LAA as a nidus for thrombus formation is well documented. Multiple approaches to exclude the LAA from the circulation either percutaneously or surgically have been described and are undergoing testing. Although pharmacological therapy for stroke prevention remains the cornerstone of treatment, device and surgical exclusion of the LAA have proven to be viable alternatives in carefully selected patients. Even though current evidence show that LAA occlusion is safe and effective, approval and adoption of this strategy has been quite difficult due to paucity of randomised clinical trial data on the risk and benefit ratio, cost effectiveness and the issues of procedural risk as well as longer-term outcome. This review aims to provide an update on the current status of LAA occlusion, specifically looking at interpretation of current clinical data, available techniques and devices, issues with current devices and future direction.

INTRODUCTION Thromboembolism in patients with atrial fibrillation (AF) most commonly leads to stroke, and by virtue of its endemic nature and devastating consequences, approaches to reduce thrombus formation in patients with AF remain a major cardiovascular issue, a great clinical need and a fertile field of investigation.1 The left atrial appendage (LAA) has been implicated in 90% of thrombus formation in patients with non-valvular AF,2 3 and approaches aimed at reducing thrombus formation in LAA continue to be explored.4–7 In recent years, mechanical approaches for the exclusion of LAA from the circulation using surgical or percutaneous means have been developed and have been found to be a viable alternative to antithrombotic therapy using oral anticoagulants for stroke prevention. This review will focus on the latest developments in the field and areas of controversy regarding this technique.


To cite: Alli O, Holmes D. Heart Published Online First: [please include Day Month Year] doi:10.1136/heartjnl2014-306255

LAA has long been recognised as the site of clot formation in a majority of patients with nonvalvular AF. Weiss and colleagues proposed the theory that clot formation occurs in LAA in patients with rheumatic mitral stenosis.8 Madden then reported the first two cases of surgical LAA removal in patients with rheumatic mitral stenosis and AF.2 Blackshear and Odell, in their review of 23 studies in which LAA was examined, found that

222 (17%) of 1288 non-valvular patients with AF had LAA thrombus and 201 (91%) of these were localised to LAA.9

STROKE AND BLEEDING RISK PREDICTION MODELS Given the risk of stroke versus the issue of bleeding, a variety of risk stratification scores have been developed and tested. The CHADS2 score is the most widely used risk stratification scheme that has been validated to provide significant risk discrimination for evaluation of stroke risk in patients with AF.10 It assigns one point for heart failure, hypertension, age ≥75 years, and diabetes mellitus and two points for prior stroke or transient ischaemic attack. A more recent update that is now more widely used is the CHA2DS2-VASc score, which includes three additional risk factors for ischaemic stroke; age 65–74 years, female sex and vascular disease have supplanted the CHADS2 score and have been validated in several cohorts of patients with AF providing significant discrimination of stroke risk.11 12 In terms of bleeding risk prediction, the Hypertension, Abnormal Renal/Liver Function, Stroke, Bleeding History or Predisposition, Labile INR, Elderly, Drugs/Alcohol Concomitantly (HAS-BLED) score has been validated and shown to offer useful predictive capacity for assessment of bleeding risk compared with other risk tools.13 A recent study compared the HAS-BLED score with two other bleeding risk prediction scores,14 ATRIA (anticoagulation and risk factors in AF) and HEMORR2HAGES (hepatic or renal disease, ethanol abuse, malignancy, older age, reduced platelet count or function, rebleeding, hypertension, anaemia, genetic factors, excessive fall risk and stroke), with the HAS-BLED score performing best in predicting clinically relevant bleeds.

IMAGING LAA In recent years, an important advance has been the use of multimodality imaging techniques (cardiac CT, cardiac MRI and transesophageal echocardiography (TEE)) to accurately characterise the anatomy of LAA. The use of cardiac CT imaging has led to detailed assessment of LAA. Although the orifice of LAA was initially thought to be circular in shape, it has now been defined as being irregular. The anatomic variability of LAA has important implications for endovascular device closure; the LAA orifice is oval or irregular and current devices are circular, accordingly placement may leave behind residual leaks. The length and angulation of LAA may also make device closure difficult, as all current endovascular devices require a definite but variable length for safe deployment. The Amplatzer cardiac plug (ACP) device is anchored in the neck

Alli O, et al. Heart 2014;0:1–8. doi:10.1136/heartjnl-2014-306255


Copyright Article author (or their employer) 2014. Produced by BMJ Publishing Group Ltd (& BCS) under licence.

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Review of LAA while the WATCHMAN device is anchored in the ostium of LAA. The LARIAT device, which is an epicardial suture device, also requires specific LAA anatomy for appropriate device use; the LAA width must be

Left atrial appendage occlusion.

Left atrial appendage (LAA) occlusion for stroke and thromboembolism prevention in patients with atrial fibrillation (AF) represents a significant adv...
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