Left Atrial Appendage Device Research Articles

Effectiveness of Left Atrial Appendage Exclusion Procedures to Reduce the Risk of Stroke: A Systematic Review of the Evidence.

Atrial fibrillation is an important cause of cardioembolic stroke. Oral anticoagulants (OAC) reduce stroke risk but increase the risk of serious bleeding. Left atrial appendage (LAA) procedures have been developed to isolate the LAA from circulating blood flow, as an alternative to OAC. We conducted a systematic review of the benefits and harms of surgical and percutaneous LAA exclusion procedures. We searched multiple data sources, including Ovid MEDLINE, Cochrane, and Embase, through January 7, 2015. Of 2567 citations, 20 primary studies met prespecified inclusion criteria. We abstracted data on patient characteristics, stroke, mortality, and adverse effects. We assessed study quality and graded the strength of evidence using published criteria. Trials found low-strength evidence that percutaneous LAA exclusion confers similar risks of stroke and mortality as continued OAC, but this evidence was limited to the Watchman device in patients eligible for long-term OAC. Observational studies found moderate-strength evidence of serious harms with a variety of percutaneous LAA procedures. There is low-strength evidence that surgical LAA exclusion does not add significant harm during heart surgery for another indication, but evidence on stroke reduction is insufficient. There is limited evidence that the Watchman device may be noninferior to long-term OAC in selected patients. Data on effectiveness of LAA exclusion devices is lacking in patients ineligible for long-term OAC. Percutaneous LAA devices are associated with high rates of procedure-related harms. Although surgical LAA exclusion during heart surgery does not seem to add incremental harm, there is insufficient evidence of benefit.

The New 3D Printed Left Atrial Appendage Closure with a Novel Holdfast Device: A Pre-Clinical Feasibility Animal Study.

IntroductionMany patients undergoing cardiac surgery have risk factors for both atrial fibrillation (AF) and stroke. The left atrial appendage (LAA) is the primary site for thrombi formation. The most severe complication of emboli derived from LAA is stroke, which is associated with a 12-month mortality rate of 38% and a 12-month recurrence rate of 17%. The most common form of treatment for atrial fibrillation and stroke prevention is the pharmacological therapy with anticoagulants. Nonetheless this form of therapy is associated with high risk of major bleeding. Therefore LAA occlusion devices should be tested for their ability to reduce future cerebral ischemic events in patients with high-risk of haemorrhage.AimThe aim of this study was to evaluate the safety and feasibility of a novel left atrial appendage exclusion device with a minimally invasive introducer in a swine model.Materials and MethodsA completely novel LAA device, which is composed of two tubes connected together using a specially created bail, was designed using finite element modelling (FEM) to obtain an optimal support force of 36 N at the closure line. The monolithic form of the occluder was obtained by using additive manufacturing of granular PA2200 powder with the technology of selective laser sintering (SLS). Fifteen swine were included in the feasibility tests, with 10 animals undergoing fourteen days of follow-up and 5 animals undergoing long-term observation of 3 months. For one animal, the follow-up was further prolonged to 6 months. The device was placed via minithoracotomy. After the observation period, all of the animals were euthanized, and their hearts were tested for LAA closure and local inflammatory and tissue response.ResultsAfter the defined observation period, all fifteen hearts were explanted. In all cases the full closure of the LAA was achieved. The macroscopic and microscopic evaluation of the explanted hearts showed that all devices were securely integrated in the surrounding tissues. No pericarditis or macroscopic signs of inflammation at the site of the device were found. All pigs were in good condition with normal weight gain and no other clinical symptoms.ConclusionThis novel 3D printed left atrial appendage closure technique with a novel holdfast device was proven to be safe and feasible in all pigs. A benign healing process without inflammation and damage to the surrounding structures or evidence of new thrombi formation was observed. Moreover, the uncomplicated survival and full LAA exclusion in all animals demonstrate the efficacy of this novel and relatively cheap device. Further clinical evaluation and implementation studies should be performed to introduce this new technology into clinical practice.

TCT-729 Percutaneous left atrial appendage closure in patients with non-valvular atrial fibrillation with Watchman® left atrial appendage device: single center experience and results up to three years follow-up

Percutaneous left atrial appendage closure (LAAC) has been although recognized as a new interventional routine, but the clinical experience with large number of patients from single hospital without cardiac surgery was worldwide very little. We evaluate patient selection, safety, feasibility, and

Evaluación de las características morfológicas de la aurícula izquierda por tomografía computarizada multicorte

ObjectiveDescribe the anatomical characteristics of the left atrium and pulmonary veins in patients with paroxysmal or persistent atrial fibrillation using computed tomography images and the possible impact these might have on pulmonary vein ablation and percutaneous left atrial appendage occlusion. MethodsEvaluation of computed tomography images from adult patients with paroxysmal or persistent atrial fibrillation who were treated with pulmonary vein ablation from January 1st, 2011 to June 30th 2012. Patients with previous cardiac surgery, pulmonary vein ablation or permanent atrial fibrillation were excluded. Multiplanar reconstrucion was performed in all patients, with three dimensional and endoluminal reconstruction performed in select patients. ResultsForty six patients (37 male, 80.5%) with a mean age of 59.7±11.1 years (range: 22-81 years) were included. Accessory veins were common, most of them on the right side with only one case of left sided accessory vein. A larger size of the venous ostia and a longer distance from the ostia to the first bifurcation than previously described was found. A total of 11 patients (24%) had a left atrial appendage ostium diameter larger than 28.5mm and 9 patients (19.5%) had a diameter larger than 30mm, which is the maximum limit for the use of left atrial appendage devices. ConclusionsAnatomical characteristics of the left atrium and pulmonary veins have variations in different populations which should be taken into account prior to pulmonary vein ablation and left atrial appendage occlusion.

Left atrial catheter ablation subsequent to Watchman® left atrial appendage device implantation: a single centre experience.

Left atrial appendage device occlusion is an increasingly accepted therapy for stroke prevention in atrial fibrillation. The feasibility and safety of left atrial catheter ablation procedures in the presence of a left atrial appendage device implant is unclear. We report on 10 cases of successful left atrial catheter ablation therapy for atrial fibrillation in patients with an implanted Watchman® device. Consecutive patients with an existing Watchman® left atrial appendage implant and symptomatic antiarrhythmic-drug refractory atrial fibrillation or atrial tachycardias requiring left atrial catheter ablation therapy were included. Open irrigated tip ablation and circular mapping catheters were positioned in the left atrium via double transseptal access. Ten patients underwent successful left atrial geometry creation and complex atrial arrhythmia mapping and ablation in the presence of a chronically implanted Watchman® device. Arrhythmia targets included left atrial flutters, a focal tachycardia, left atrial CFAE zones, and pulmonary vein electrical isolation. The appearances of the Watchman® device position and device integrity were confirmed to be satisfactory in all patients at the end of the procedure based on fluoroscopy and intracardiac echocardiography imaging. There were no procedural complications. Left atrial catheter ablation therapy in the presence of an implanted Watchman® left atrial appendage occlusion device was efficacious and uncomplicated in our small single centre experience.

Cardiac CT angiography for device surveillance after endovascular left atrial appendage closure.

Left atrial appendage (LAA) device imaging after endovascular closure is important to assess for device thrombus, residual leak, positioning, surrounding structures, and pericardial effusion. Cardiac CT angiography (CCTA) is well suited to assess these non-invasively. We report our consecutive series of non-valvular atrial fibrillation patients who underwent CCTA post-LAA closure with Amplatzer Cardiac Plug (ACP), Amulet (second generation ACP), or WATCHMAN devices. Patients underwent CCTA typically 1-6 months post-implantation. Prospective cardiac-gated CCTA was performed with Toshiba 320-detector or Siemens 2nd generation 128-slice dual-source scanners, and images interpreted with VitreaWorkstation™. GFR <30 mL/min/1.73 m(2) was an exclusion. We assessed for device thrombus, residual LAA leak, device embolization, position, pericardial effusion, optimal implantation, and device lobe dimensions. Forty-five patients underwent CCTA at median 97 days post-LAA closure (18 ACP, 9 Amulet, 18 WATCHMAN). Average age was 75.5 ± 8.9 years, mean CHADS2 score 3.1 ± 1.3, and CHADS-VASc score 4.9 ± 1.6. All had contraindications to oral anticoagulation. Post-procedure, 41 (91.1%) were discharged on DAPT. There was one device embolization (ACP, successfully retrieved percutaneously) and one thrombus (WATCHMAN, resolved with 3 months of warfarin). There were two pericardial effusions, both pre-existing and not requiring intervention. Residual leak (patency) was seen in 28/44 (63.6%), and the mechanisms of leak were readily identified by CCTA (off-axis device, gaps at orifice, or fabric leak). Mean follow-up was 1.2 ± 1.1year, with no death, stroke, or systemic embolism. CCTA appears to be a feasible alternative to transoesophageal echocardiography for post-LAA device surveillance to evaluate for device thrombus, residual leak, embolization, position, and pericardial effusion.

How Could Pre-Procedural Imaging Guide Successful Left Atrial Appendage Closure?

REFER TO THE PAGE 211-218 Atrial fibrillation (AF) is the most common sustained arrhythmia and strongly associated with ischemic stroke.1) In patients with AF, the main site of thrombus formation is the left atrial appendage (LAA).2) Autopsy and surgical data have suggested that about 90% of atrial thrombi in AF patients originate from the LAA.3) There are two reasonable ways to prevent ischemic stroke events in patients with AF. The first is maintenance of anticoagulation. The second is to isolate the LAA as a major embolic source from the systemic circulation. Multiple randomized, controlled trials have suggested that oral anticoagulation (OAC) decrease the risk of stroke in patients with AF.4) However, long-term OAC is contraindicated in 14% to 44% of AF patients with risk of stroke.5) Because there are various barriers against maintenance of long-term OAC such as the risk of bleeding, inconvenience of dose adjustments, drug interactions, and restrictions on diet.6) Other novel anticoagulants are also limited by the side effects, and the risk of bleeding from systemic administration of these agents.7) Because the LAA is a separate anatomic structure, it may be relatively easily isolated from systemic circulation by excision or ligation. Recently, less invasive technique using percutaneous transcatheter have been introduced for LAA isolation by occlusion of this anatomical structure with implantable devices.8) The PROTECT AF (Watchman Left Atrial Appendage System for Embolic Protection in Patients with Atrial Fibrillation) trial was planned to determine whether systemic anticoagulation with warfarin, the most commonly used anticoagulant, could be replaced by LAA closure with a percutaneously positioned device. This final results of the PROTECT AF trial followed up for an accumulated exposure of 1588 patient-years revealed LAA closure with the Watchman device to be non-inferior to systemic anticoagulation with warfarin regarding prevention of stroke, systemic embolism, and cardiovascular death.9) On the basis of these data, LAA closure has been decided a class IIb recommendation in the 2014 ACC/ASA guideline as an alternative strategy to prevent stroke. For this procedure to be accepted as an alternative, there must be a high success rate. Although success rate of the LAA closure is generally high, peri-device leakage of LAA persists due to incomplete closure.9),10) During percutaneous LAA closure for stroke prophylaxis, the geometric variability of the LAA ostium may result in an incomplete seal of the LAA. To understand the technical limitations of LAA closure, it is important to consider the anatomical variations of the LA and LAA geometry. The geometry of LA and LAA, a detailed knowledge of its anatomical characteristics and relationship might be very useful when planning the procedure. As LA and LAA geometry is complex, there are limited available data about the predictors of successful procedure. The anatomical relationship of LAA and interatrial septum (IAS) may affects the success rate of device implantation.11) In this issue, Chung et al.12) introduced 3-dimensional anatomical relation of IAS and LAA orifice as a predictor of peri-device leakage after LAA closure. One of the novel and interesting aspects of this study is that they use new novel analysis program for accurate measurement of 3-dimensional relationship between IAS and LAA orifice and found that 3-dimensional angulation between IAS and LAA significantly associated with development of peri-device leakage after LAA occlusion. In this study, the angle between the IAS plane and the line linking the LAA orifice midline and foramen ovale was measured using 3-dimensional geometric cardiac CT analysis. Measurement of this new parameter can provide more detail geometric information and predict success of the procedure. In addition, it might be helpful to select catheter and to decide the direction of IAS puncture site. This study is the first study that anatomical relationship of IAS and LAA orifice might affect peri-device leakage. However, clinical implication of peri-device leakage after LAA occlusion is unclear. Despite some previous studies suggested that the incomplete LAA occlusion was not associated with cardioembolic stroke event,10) understanding the clinical impact of peri-device leakage would be critical. As the authors commented in the limitation, larger sample size, prospective and long-term follow up data are needed to determine the clinical implication of peri-device leak after LAA occlusion. Despite some limitations, this study results suggested that novel anatomical parameter could be measured by their new software and this parameter is useful to predict peri-device leakage after LAA device closure.

Predicting Peri-Device Leakage of Left Atrial Appendage Device Closure Using Novel Three-Dimensional Geometric CT Analysis.

BackgroundAfter left atrial appendage (LAA) device closure, peri-device leakage into the LAA persists due to incomplete occlusion. We hypothesized that pre-procedural three-dimensional (3D) geometric analysis of the interatrial septum (IAS) and LAA orifice can predict this leakage. We investigated the predictive parameters of LAA device closure obtained from baseline cardiac computerized tomography (CT) using a novel 3D analysis system.MethodsWe conducted a retrospective study of 22 patients who underwent LAA device closure. We defined peri-device leakage as the presence of a Doppler signal inside the LAA after device deployment (group 2, n = 5) compared with patients without peri-device leakage (group 1, n = 17). Conventional parameters were measured by cardiac CT. Angles θ and φ were defined between the IAS plane and the line, linking the LAA orifice center and foramen ovale.ResultsGroup 2 exhibited significantly better left atrial (LA) function than group 1 (p = 0.031). Pre-procedural θ was also larger in this group (41.9° vs. 52.3°, p = 0.019). The LAA cauliflower-type morphology was more common in group 2. Overall, the patients' LA reserve significantly decreased after the procedure (21.7 mm3 vs. 17.8 mm3, p = 0.035). However, we observed no significant interval changes in pre- and post-procedural values of θ and φ in either group (all p > 0.05).ConclusionAngles between the IAS and LAA orifice might be a novel anatomical parameter for predicting peri-device leakage after LAA device closure. In addition, 3D CT analysis of the LA and LAA orifice could be used to identify clinically favorable candidates for LAA device closure.

Left atrial appendage device closure as non-pharmacological prevention of thromboembolism in atrial fibrillation

Left atrial appendage device closure as non-pharmacological prevention of thromboembolism in atrial fibrillation

Watchman LAA Closure Device in Patients with AF

This article presents the results from the Watchman Left Atrial Appendage System for Embolic Protection in Patients With Atrial Fibrillation trial [PROTECT AF; NCT00129545] that compared the Watchman left atrial appendage device with warfarin therapy for patients with atrial fibrillation.

Evaluation of the WATCHMAN left atrial appendage closure device

Left atrial appendage device occlusion for the preventions of systemic thromboembolism and stroke represents a major breakthrough in the field of cardiovascular disease. The wide prevalence of atrial fibrillation with devastating consequences of thromboembolic stroke as a result of thrombus arising from the left atrial appendage has led to the development of transcatheter and surgical based occlusion devices. Though this device is yet to be formally approved for a clinical indication in the USA, the WATCHMAN appendage occlusion device remains the most rigorously examined and studied of all transcatheter-based devices in this space. This review will focus on the needs assessment in this space, the technology of the current WATCHMAN device, trials and studies looking at safety and efficacy, specific patient populations who might benefit as well as future perspectives.

Left atrial appendage devices for stroke prevention in atrial fibrillation.

Atrial fibrillation (AF) is the most commonly encountered clinical arrhythmia, and stroke prevention remains an integral part of management of AF. Long-term therapy with oral anticoagulants, though effective, has many limitations, and these limitations have encouraged the search for device-based alternatives. In patients with non-valvular AF, approximately 90% of thrombi are thought to arise from the left atrial appendage (LAA). The LAA can be obliterated surgically or percutaneously, and this should reduce the incidence of systemic thromboembolic events in AF, ideally without the need for further anticoagulation. We explore the currently available LAA occlusion devices and the evidence behind these devices. Although additional evidence from randomized trials is required to fully characterize the safety and efficacy of all of these devices, LAA occlusion has the potential to offer an attractive alternative for those at high stroke risk but are under-protected because of contraindications to anticoagulant therapy.

TCT-798 Anatomical Effect on Left Atrial After Transcatheter Left Atrial Appendage Devices: Watchman and Amplatzer Cardiac Plug in a Canine Model

TCT-798 Anatomical Effect on Left Atrial After Transcatheter Left Atrial Appendage Devices: Watchman and Amplatzer Cardiac Plug in a Canine Model

Tools and Techniques Clinical: Transcatheter closure of left atrial appendage using the Amplatzer™ Cardiac Plug

Background Since chronic oral anticoagulation cannot be administered in a substantial proportion of patients with atrial fibrillation, the endovascular exclusion of the left atrial appendage (LAA), which represents the source of atrial-derived emboli in the majority of cases, has been proposed as a valuable alternative in selected patients. In this article we briefly summarise the basic steps to perform an effective and safe implantation procedure using the AmplatzerTM Cardiac Plug (ACP; St. Jude Medical, Plymouth, MN, USA). Methods First, both cardiac computed tomography and transoesophageal echocardiography should be complementarily performed to study LAA anatomy and size accurately (Figure 1). LAA dimensions must be validated and confirmed during the procedure either by TEE or intracardiac echo (ICE) and angiographic measurements. It is recommended that the AmplatzerTM Cardiac Plug be oversized by about 2 to 3 mm with respect to the LAA measurements. Second, a transseptal puncture, using either the Mullins sheath (Medtronic AVE, Galway, Ireland) or the SL1 sheath (St. Jude Medical, Plymouth, MN, USA), should be performed in the lower part of the fossa ovalis. Third, after the advancement of a marker pigtail catheter (5 Fr, 100 cm long) through the transseptal sheath and the localisation of the pigtail catheter inside the LAA, perform an LAA angiogram to size the LAA ostium and “neck” angiographically. Fourth, prepare the LAA device accurately in

Current and Evolving Clinical Applications of Multidetector Cardiac CT in Assessment of Structural Heart Disease

Multidetector computed tomography (CT) has an established role in the evaluation of selected patients suspected of having coronary disease; however, in addition to coronary assessment, multidetector CT can be used to evaluate numerous noncoronary structures in the same examination. In particular, the use of multidetector CT to provide pulmonary and cardiac venous anatomic information prior to electrophysiology procedures is well established, and its important role in the periprocedural evaluation of patients undergoing percutaneous procedures, such as transcatheter aortic valve replacement and left atrial appendage device occlusion, is being increasingly recognized. Such advances have resulted in multidetector CT being increasingly used as a complementary imaging technique to echocardiography and magnetic resonance imaging for the comprehensive evaluation of cardiac structure and function in particular clinical situations. This review provides an overview of the noncoronary cardiac structures that can be evaluated with multidetector CT, and outlines the established appropriate clinical uses of multidetector CT in the assessment of structural heart disease, as well as evolving periprocedural clinical applications.

Percutaneous left atrial appendage closure for stroke prevention in atrial fibrillation

Percutaneous left atrial appendage (LAA) closure can be an alternative to coumadin treatment in patients with atrial fibrillation (AF) at high risk for thromboembolic events and/or bleeding complications. We report the initial experience with this new technique. Patients were eligible if they had AF with a high stroke risk (CHADS(2) score >1), and/or contraindication for coumadin therapy. The procedure was performed under general anaesthesia, using biplane fluoroscopy and (3D) transoesophageal echocardiography (TEE) guidance. Patients were discharged on coumadin until a TEE was repeated at 45days after closure to evaluate LAA occlusion. If LAA occlusion was achieved, oral anticoagulation was discontinued and aspirin started. Percutaneous LAA closure was performed in 10 patients (50% male, age 61.6 ± 9.6years). The median CHADS(2) score was 3 (range 2-4), median CHA(2)DS(2)-VASc score 3.5 (range 2-6) and HAS-BLED score 1.5 (range 1-4). Nine patients had a history of stroke and 2 patients had a history of major bleeding while on coumadin. Concomitant pulmonary vein isolation was performed in 9 patients. The device was successfully placed in all patients within a median of 56min (38-137min). Asymptomatic catheter thrombus occurred in one patient. At 45-day follow-up, no thromboembolic events occurred, TEE showed minimal residual flow in the LAA in three patients. In one patient the LAA device was dislocated, requiring successful percutaneous retrieval. Device closure of the LAA may provide an alternative strategy to chronic coumadin therapy in patients with AF and high risk of stroke and/or bleeding complications using coumadin.

Left Atrial Appendage Obliteration: Mechanisms of Healing and Intracardiac Integration

The objectives of this study were: 1) to delineate the temporal course of histopathologic healing as the left atrial appendage (LAA) is obliterated by a mechanical device; and 2) to compare this process with other intravascular and intracardiac implanted technologies. Intracardiac device healing is incompletely understood. We thus studied the histopathology of device-based LAA obliteration. Nine dog hearts were examined over time after LAA device placement and results were compared with human hearts with prior LAA obliteration using the same device. At 3 days in dogs, atrial surfaces were covered by fibrin, which sealed gaps between the LA wall and the device and filled the LA appendage cavity. At 45 days, endothelial cells covered the endocardial surface with underlying smooth muscle cells that sealed the device-LA interface. Regions with prior thrombus were replaced by endocardium surrounding the device membrane. Disorganized thrombus remained in the LAA body and at the periphery near the appendage walls. Mild inflammation was observed as thrombus resorbed. By 90 days, a complete endocardial lining covered the former LAA ostium. Organizing thrombus had become connective tissue, with no residual inflammation. The human necropsy hearts had similar findings. In these 4 hearts (139, 200, 480, and 852 days after implant), the ostial fabric membrane was covered with endocardium. The appendage surface contained organizing thrombus with minimal inflammation. Organizing fibrous tissue was inside the LAA cavity, prominent near the atrial wall. The LAA interior contained organizing thrombus. This intracardiac device integration study delineated healing stages of early thrombus deposition, thrombus organization, inflammation and granulation tissue, final healing by connective tissue, and endocardialization without inflammation. These observations may yield insight into cellular healing processes in other cardiac devices.