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Background: Left atrial appendage occlusion (LAAO) represents a treatment alternative to anticoagulation in patients with atrial fibrillation. We evaluate a novel device for epicardial LAAO in a translational canine model., Methods: Nine hounds (n = 9) were used to assess usability, safety, and efficacy of the TigerPaw Pro (TPP) device for epicardial LAAO. Following baseline imaging (intra-cardiac echocardiography (ICE) and angiography) and intraoperative visual inspection, usability was tested via a ``closure/re-opening`` maneuver followed by deployment of a total of twenty TPP devices (n = 20) on the left and right atrial appendages respectively. Procedural safety was evaluated by assessing for adverse-events via direct Epicardial inspection and endocardial imaging. Efficacy evaluation included assessment of device positioning, presence of residual stumps and completeness of closure. Post-mortem evaluation was performed to confirm safety and efficacy., Results: Usability testing of all TPP devices was successful (n = 20;100%, delivery-time range 22-120 s) without any procedural adverse-events (tissue damage or tears, bleeding, vessel-impingement, structural impact). All devices fully traversed the ostium (n = 18) or appendage body (n = 2), and conformed smoothly to adjacent cardiac anatomy. In nineteen deployments (n = 19;95%), all device connector pairs were fully engaged, while in one TPP device the most distal pair remained unengaged. ICE and post-mortem inspections revealed complete closure of all appendage ostia (n = 18;100%) and only in one case a small residual stump was detected. Intraoperative safety findings were further confirmed post-mortem. Devices created a nearly smooth line of closure via symmetric endocardial tissue-coaptation., Conclusions: In this preclinical model, the TPP demonstrated good ease of use for ostial access, ability to re-position (after engagement) and rapid deployment, while achieving safe and effective LAAO.

Background: Percutaneous left atrial appendage exclusion (LAAE) has evolved as an alternative strategy for stroke prevention in atrial fibrillation (AF). Recent observational data have suggested that epicardial LAAE can have substantial impact on arrhythmia burden and hemodynamic profile., Objectives: The authors aimed to study the impact of epicardial versus endocardial LAAE on systemic blood pressure in hypertensive AF patients., Methods: This was a prospective, nonrandomized study comparing 247 patients who underwent epicardial LAAE with 124 patients with endocardial exclusion. Clinical outcomes were measured at 3 months and 1 year. Primary outcome was improvement in systolic blood pressure (SBP) between both groups compared with baseline. Secondary outcome included changes in diastolic pressures (DBP), serum electrolytes, and creatinine., Results: There was no significant difference in baseline SBP between epicardial and endocardial groups. SBP was significantly lower in the epicardial group both at 3 months (122 ± 11.8 mm Hg vs. 129.7 ± 8.2 mm Hg; p < 0.001) and 1 year (123 ± 11.6 mm Hg vs. 132.2 ± 8.8 mm Hg; p < 0.001) compared with the endocardial group. An adjusted multivariate linear mixed effects model demonstrated that epicardial LAAE significantly decreased SBP by 7.4 mm Hg at 3 months and by 8.9 mm Hg at 1 year (p < 0.0001). There was a trend toward lower DBP with epicardial LAAE at 3 months by 1.3 mm Hg (p = 0.2) and at 1 year by 1.8 mm Hg (p = 0.09). There was no significant difference in serum electrolytes and creatinine between both groups., Conclusions: In hypertensive AF patients, epicardial LAAE significantly decreases SBP both at 3 and 12 months compared with endocardial exclusion., (Copyright © 2018 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Aims: Left atrial appendage (LAA) occlusion has emerged as an interesting alternative to oral anticoagulation (OAC) for stroke prevention in patients with atrial fibrillation (AF). We report the safety, efficacy, and durability of concomitant device-enabled epicardial LAA occlusion during open-heart surgery. In addition to long-term follow-up, we evaluate the impact on stroke risk in this selected population., Methods and Results: A total of 291 AtriClip devices were deployed epicardially in patients (mean CHA2DS2-VASc-Score: 3.1 ± 1.5) undergoing open-heart surgery (including isolated coronary artery bypass grafting, valve, or combined procedures) comprising of forty patients from a first-in-man device trial (NCT00567515) and 251 patients from a consecutive institutional registry thereafter. In all patients (n = 291), the LAA was successfully excluded and overall mean follow-up (FU) was 36 ± 23months (range: 1-97 months). No device-related complications were detected throughout the FU period. Long-term imaging work-up (computed tomography) in selected patients ≥5years post-implant (range: 5.1-8.1 years) displayed complete LAA occlusion with no signs of residual reperfusion or significant LAA stumps. Subgroup analysis of patients with discontinued OAC during FU (n = 166) revealed a relative risk reduction of 87.5% with an observed ischaemic stroke-rate of 0.5/100 patient-years compared with what would have been expected in a group of patients with similar CHA2DS2-VASc scores (expected rate of 4.0/100 patient-years). No strokes occurred in the subgroup with OAC., Conclusion: The long-term results from our first-in-man prospective human trial plus our institutional registry of epicardial LAA occlusion with the AtriClip in patients with AF undergoing cardiac surgery demonstrate the safety and durability of the procedure. In addition, our data are suggestive for the potential efficacy of LAA occlusion in reducing the incidence of stroke. If validated in future large randomized trials, routine LAA occlusion in patients undergoing cardiac surgery (with contraindications to treatment with oral anticoagulants) may represent a reasonable adjunct procedure to reduce the risk of future stroke., Clinical Trial Registration: URL: http://www.clinicaltrials.gov. Unique identifier: NCT00567515.

The increasing prevalence of atrial fibrillation with the aging population and its associated major morbidity and mortality due to thromboembolic stroke have resulted in intensive research on stroke prevention or stroke risk reduction strategies. Several surgical techniques for left atrial appendage (LAA) occlusion have evolved over the past decades. Surgeons have been using different techniques leading to highly variable and, in particular, poor data on outcomes. LAA closure is performed either as a concomitant procedure during open-heart surgery or as a stand-alone surgical procedure as part of minimally invasive (mini-thoracotomy or thoracoscopy) arrhythmia surgery. Data on the safety and feasibility of surgical LAA occlusion are derived mainly from nonrandomized case series, observational and cohort studies, or registries with mostly inconclusive and conflicting results. Increased awareness of the high failure rates in attaining complete LAA occlusion, thus avoiding poor surgical techniques (e. g., simple suture ligation, endocardial suturing etc.), and the availability of newer devices (e. g., AtriClip device) have recently led to improved surgical results in the literature. If further validated in large-scale studies, these recent promising developments in the field of surgical LAA treatment seem to offer alternatives for patients ineligible for oral anticoagulation therapy with vitamin K antagonists or newer non-vitamin-K-dependent oral anticoagulants.

With a steadily increasing prevalence, atrial fibrillation (AF) is the most common sustained cardiac arrhythmia worldwide and an independent risk factor for stroke caused by thromboembolic events. The left atrial appendage (LAA) is the primary source of thromboemboli in patients with nonvalvular AF who have a stroke. Novel strategies (such as mechanical and nonpharmacological intervention) targeting the LAA in patients with AF for stroke prevention have become a major focus during the past decade. Some devices for percutaneous LAA occlusion are supported by robust clinical data obtained from randomized trials or large registries, and are a valid alternative to pharmacological stroke prevention. However, the incidence of periprocedural complications and the presence of device-related thrombi or residual LAA leaks, whose long-term clinical implications are still unknown, are limiting factors in wider acceptability of these techniques. In this Review, we discuss the available techniques for LAA occlusion in patients with nonvalvular AF at high risk of stroke. We describe the pharmacological and mechanical approaches to LAA occlusion, and provide the current clinical evidence for various strategies. We particularly focus on the current management of the LAA, and discuss the challenges and future implications of the available approaches to LAA occlusion.

Objectives: The aim of the study was to examine frequency, size, and localization of peri-device leaks after percutaneous left atrial appendage (LAA)-closure with the AMPLATZER-Cardiac-Plug (ACP) by using a multimodal imaging approach, i.e. combined cardiac-CT and TEE follow-up., Background: Catheter-based LAA-occlusion using ACP aims to reduce the risk of stroke in patients with atrial fibrillation. Detection of peri-device leaks after ACP implantation by TEE is challenging, the few available data are inconsistent and the frequency of LAA leaks after ACP implantation remains therefore unclear., Methods: Cardiac-CT using a multi-phase protocol and a second-generation dual-source-CT-system was performed in 24 patients with non-valvular atrial fibrillation starting 3 months after LAA-closure by ACP. Color Doppler multiplane TEE was used to evaluate peri-device flow., Results: Cardiac-CT follow-up detected any persistent LAA contrast filling in 62% of patients (n = 15), but leak-sizes were small (1.5 ± 1.4 mm). Peri-device leaks were almost exclusively localized at the posterior portion of the LAA-orifice (>90%). TEE follow-up revealed peri-device flow in 36% of patients (jet-sizes: ≤ 4 mm). ACP-lobe compression (>10%) and perpendicular ACP-lobe orientation to the LAA-neck axis, that was also dependent on LAA anatomy, were substantially more frequent in patients with complete LAA closure., Conclusion: The present study evaluates for the first time peri-device flow after LAA closure by ACP using a combined cardiac-CT and TEE follow-up. Persistent LAA-perfusion was frequently detected, leak-sizes were small and were less frequent when lobe compression was >10% and lobe orientation was perpendicular to the LAA-neck axis, that was also related to the LAA anatomy. The clinical significance of these small leaks after LAA-closure using ACP needs to be further evaluated in future studies., (© 2014 Wiley Periodicals, Inc.)

Objectives: The exclusion of the left atrial appendage (LAA) has been used to reduce the risk of stroke associated with atrial fibrillation (AF). While LAA exclusion has been associated with a reduced risk of stroke, the effect on the electrical activity of the LAA (a potential source of AF) remains unknown. As such, we sought to demonstrate whether surgical epicardial clip occlusion leads to the electrical isolation of the LAA., Methods: From December 2010 until August 2011, 10 patients with paroxysmal AF underwent off-pump coronary artery bypass surgery with bilateral pulmonary vein isolation and an LAA clip occlusion with a new epicardial clip. Before and after the clip was placed, pacing manoeuvres were performed to assess the electrical exit and entry blocks from the LAA., Results: All clips were applied successfully. The mean procedure time for the clip application was 4 ± 1 min. No complications occurred related to clip application. Prior to the pericardial closure, 18 ± 3 min after the clip placement, the LAA stimulation and pacing manoeuvres demonstrated complete electrical isolation of the LAA in all cases., Conclusions: Epicardial LAA clip occlusion leads to the acute electrical isolation of the LAA and may not only provide stroke prevention but also reduce the recurrence of AF.

Objective: Atrial fibrillation puts patients at significant risk for embolic stroke originating from the left atrial appendage. Few means are available for safe, effective, and durable left atrial appendage occlusion. A new clip device was evaluated with regard to safety and effectiveness for epicardial left atrial appendage occlusion., Methods: Patients with atrial fibrillation undergoing elective cardiac surgery through a median sternotomy were enrolled for concomitant epicardial clip placement. Early postoperative and 3-month follow-up computed tomography studies were used to assess clip stability and left atrial appendage perfusion., Results: From September 2007 to December 2008, 34 patients underwent successful clip placement. No device-related complications occurred. Operative mortality was 8.8% and not study or device related. Deployment was rapid, and left atrial appendage occlusion was confirmed by intraoperative transesophageal echocardiography in all patients. In addition to excellent clinical outcomes (no stroke/transient ischemic attack), serial computed tomography demonstrated stable clip location and appendage perfusion at 3 months in all patients., Conclusion: Safe, effective, and durable left atrial appendage occlusion can easily be achieved with this new clip. Further trials are necessary to evaluate the role of the left atrial appendage occlusion in stroke prevention., (2010 The American Association for Thoracic Surgery. Published by Mosby, Inc. All rights reserved.)

Objective: Management of the left atrial appendage (LAA) is considered an important adjunct to ablation in cardiac surgical patients with atrial fibrillation (AF). However, current surgical techniques, both cut-and-sew and stapling, have been associated with incomplete LAA occlusion and complications. Using cardiac magnetic resonance imaging (MRI), we studied the safety and effectiveness of a new device for LAA occlusion in a primate model., Methods: Seven adult baboons underwent off-pump placement of an LAA clip (AtriCure Inc., Westchester, Ohio). LAA occlusion was confirmed intraoperatively by direct incision. All animals had MRI before and after clip placement to assess LAA perfusion, architecture, and overall cardiac function. Pathologic and histological studies were performed at 7, 30 and 180 days., Results: Clip placement was successful in all (n=7) without any clip related complications. Complete LAA occlusion was demonstrated intraoperatively in all subjects. LAA occlusion was confirmed on pre-sacrifice MRI, and left and right ventricular function were unchanged from preoperative studies; however, clip placement caused small reductions in left ventricular end-diastolic, end-systolic, and stroke volumes. At sacrifice, direct inspection confirmed stable location, persistent LAA exclusion, tissue in-growth and homogenous epithelialization without damage to adjacent structures. Histological analysis revealed a regular in-growth pattern in all studied specimens., Conclusion: We demonstrated a safe, straightforward, persistent and effective method for LAA occlusion with this new LAA clip. MRI effectively demonstrated LAA occlusion and only minor changes in left ventricular volumes.