Left Atrial Appendage Exclusion Devices Research Articles

Transcatheter Left Atrial Appendage Exclusion: Preclinical and Early Clinical Results With the Laminar Device

BackgroundThe Laminar device rotates and closes the left atrial appendage (LAA) using an integrated ball and lock that excludes and eliminates the LAA pouch. There is a low device surface area, minimizing the risk of peridevice leak (PDL) and device-related thrombus (DRT) formation. ObjectivesThis study evaluates the safety and efficacy of the Laminar LAA exclusion device in healthy animals and human subjects with nonvalvular atrial fibrillation at risk of ischemic stroke and systemic thromboembolism. MethodsThe preclinical study implanted the Laminar device into canine subjects that underwent transesophageal echocardiography (TEE) and fluoroscopic evaluation, followed by necropsy and histological assessment at 45 and 150-days post-implant. The early clinical study implanted the device in human subjects, followed to 12 months postimplantation. Procedural success was defined as device implantation in the intended location without residual LAA leak >5 mm as seen by TEE. Safety endpoints included freedom from stroke, systemic embolism, pericardial effusion, or tamponade, life-threatening/major bleeding, or death. ResultsThe Laminar device was successfully implanted in 10 canines. In all animals at 45 days and 150 days, no PDL or DRT was found, and histological examination showed fully closed LAAs covered with neo-endocardium. The device was successfully implanted in 15 human subjects with no safety events out to 12 months postimplantation. All subjects had successful protocol-defined LAA closure without DRT at 45 days by TEE and computed tomography, which remained stable through 12 months’ follow-up. ConclusionsThe preclinical and early clinical results demonstrate a promising safety and efficacy profile for the Laminar LAA exclusion device.

Evaluation of Local Tissue Reaction After the Application of a 3D Printed Novel Holdfast Device for Left Atrial Appendage Exclusion

The left atrial appendage (LAA) is a small, finger-like extension of the left atrium and its exclusion is used as a treatment strategy to prevent ischemic stroke. Existing holdfast devices may damage the tissue, are unisized and not adjustable. A novel holdfast device for LAA exclusion devoid of these shortcomings was designed and 3D-printed using the Selective Laser Sintering (SLS) technology with polyamide powder and tested it on animal model. We selected the SLS 3D printing technology due to its wid14e availability and low production costs which could provide on-site 3D printing for specific patient. The purpose of this study was to evaluate the biocompatibility of the reported holdfast device and compare the histological results obtained for local tissue reactions to those obtained for an established grafting material. Thirty swine subdivided into two groups were examined. The LAA exclusion device was implanted and was either coated with a polyester vascular implant or not coated at all and the histological response to the device’s presence was evaluated which is a standard approach to test the device biocompatibility. In all cases, complete occlusion was seen without any pathological findings during the incubation time. In both groups, the surface of the atrium under a holdfast device was smooth and shiny and had no clots. The foreign body reaction of the LAA holdfast device made of polyamide powder was insignificantly lower compared to the polyester graft. Thus, it fulfils the parameters of biocompatibility at the highest degree, and makes it suitable material for the manufacturing of LAA holdfast devices.

Evolution of left atrial appendage exclusion

Atrial fibrillation is independently associated with an increased risk of thromboembolic stroke. While anticoagulants decrease this risk, they also carry a substantial risk of bleeding. Most left atrial thrombi arise from the left atrial appendage (LAA), which has led to several investigations into surgical and percutaneous methods of LAA exclusion for stroke reduction. The PubMed database was queried, and over 400 articles were considered for inclusion in this review. Of the surgical methods of LAA exclusion, complete excision is the most effective. Other methods, including ligation and stapling, may be incomplete and associated with left atrial thrombus formation. Surgical LAA exclusion has been commonly performed during mitral valve surgery although it has not been shown to prevent stroke in many retrospective studies. In patients unable to take warfarin, several percutaneous LAA exclusion devices have been studied, including the PLAATO system, Amplatzer Cardiac Plug (ACP), Watchman device, and Lariat. Both the ACP and Watchman have shown a significant stroke reduction and improved procedural safety with greater experience. The Lariat ligates the LAA using a combined endocardial and epicardial approach but is currently associated with substantial procedural risks. With better patient selection for the different options of LAA exclusion, thromboembolic stroke protection can be maximized with fewer complication risks.

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.

A review of the LARIAT device: insights from the cumulative clinical experience.

Atrial fibrillation (AF) is the most common arrhythmic disorder world-wide, accounting for 15 % of all strokes. Management of stroke risk in AF is complicated by intolerance of anti-coagulation (AC) therapy and difficulty maintaining therapeutic range in patients treated with warfarin. The left atrial appendage (LAA) is a source of thrombus in AFrelated thrombo-embolic events and surgical LAA exclusion (LAAO) is commonly performed during cardiac surgery in AF patients. Surgical approaches are limited by a high incidence of incomplete closure with a potential for consequent thrombo-embolic events as well as the morbidity of an open-heart procedure. More recently, percutaneous approaches to LAAO have been developed. The LARIAT device is an epicardial LAA exclusion system that enables percutaneous suture ligation of the LAA via combined, pericardial and trans-septal access. The device has 510k Federal Drug Administration (FDA) clearance for soft-tissue ligation and has been studied in canine models in pre-clinical studies as well as published series of clinical experience with LARIAT LAAO. The history, patient selection, procedural technique and complications of LARIAT LAAO are reviewed here. Additionally, insights and procedural improvements that have been elucidated from clinical series and outcomes from the collective experience are discussed. The LARIAT’s epicardial approach to LAA ligation is unique compared with other percutaneous LAA exclusion devices, however more data regarding device safety and efficacy is needed for the LARIAT to emerge as an established therapy for stroke prevention in AF.

Simultaneous Right and Left Atrial Appendage Thrombus in a Patient with Atrial Fibrillation: A Lesson to Remember

We report a case of simultaneous right and left atrial appendage thrombi in a 76-year-old-man with atrial fibrillation. Although transesophageal echocardiography is considered a routine diagnostic procedure, complete and comprehensive visualization of both atrial appendages is of paramount importance, particularly with the introduction of new therapeutic options like left atrial appendage exclusion devices. We expect to raise awareness among clinicians of the prevalence and implications of bilateral atrial appendage thrombi in common clinical practice.

Safety and Procedural Success of Left Atrial Appendage Exclusion With the Lariat Device: A Systematic Review of Published Reports and Analytic Review of the FDA MAUDE Database.

The Lariat device has received US Food and Drug Administration (FDA) 510(k) clearance for soft-tissue approximation and is being widely used off-label for left atrial appendage (LAA) exclusion. A comprehensive analysis of safety and effectiveness has not been reported. To perform a systematic review of published literature to assess safety and procedural success, defined as successful closure of the LAA during the index procedure, of the Lariat device. We performed a formal analytic review of the FDA MAUDE (Manufacturer and User Facility Device Experience) database to compile adverse event reports from real-world practice with the Lariat. For the systematic review, PubMed, EMBASE, CINAHL, and the Cochrane Library were searched from January 2007 through August 2014 to identify all studies reporting use of the Lariat device in 3 or more patients. The FDA MAUDE database was queried for adverse events reports related to Lariat use. Data were abstracted in duplicate by 2 physician reviewers. Events from published literature were pooled using a generic inverse variance weighting with a random effects model. Cumulative and individual adverse events were also reported using the FDA MAUDE data set. Procedural adverse events and procedural success. In the systematic review, 5 reports of Lariat device use in 309 participants were identified. Specific complications weighted for inverse of variance of individual studies were urgent need for cardiac surgery (2.3%; 7 of 309 procedures) and death (0.3%; 1 of 309 procedures). Procedural success was 90.3% (279 of 309 procedures). In the FDA MAUDE database, there were 35 unique reports of adverse events with use of the Lariat device. Among these, we identified 5 adverse event reports that noted pericardial effusion and death and an additional 23 reported urgent cardiac surgery without mention of death. This review of published reports and case reports identified risks of adverse events with off-label use of the Lariat device for LAA exclusion. Formal, controlled investigations into the safety and efficacy of the device for this indication are warranted.

Left atrial appendage exclusion-Where do we stand?

Atrial fibrillation (AF) is consider to be the most common cardiac arrhythmia with an increasingly prevalence. It is postulated that the source of thromboembolism in 90% of patients with non-valvular AF arises from the left atrial appendage (LAA). Stroke is the most feared and life threatening consequence of thromboembolism. Oral anticoagulation (OAC) with vitamin-K-antagonists is the standard medical therapy for stroke prevention in patients with AF. Unfortunately, chronic therapy with vitamin-K-antagonists is contraindicated in 14% to 44% of patients with AF who are at risk for stroke, and its benefits are limited by underutilization, narrow therapeutic window and increased risk for bleeding, making it often undesired. Therefore, mechanical LAA exclusion is a means of preventing thrombus formation in the appendage and subsequent thromboembolic events in these patients. The LAA can be excluded from the systemic circulation via surgical, percutaneous, or thoracoscopic approaches. Several studies of percutaneous transcatheter delivery of dedicated LAA exclusion devices, such as the percutaneous left atrial appendage transcatheter occlusion (PLAATO) device, Watchman device and the Amplatzer cardiac plug, have shown encouraging results as an alternative to vitamin-K-antagonists therapy for selected patients, good feasibility and efficacy, with a high rate of successful implantation. We discuss the current evidence for LAA exclusion in patients and review their results.

Initial Experience With a Novel Percutaneous Left Atrial Appendage Exclusion Device in Patients With Atrial Fibrillation, Increased Stroke Risk, and Contraindications to Anticoagulation

Atrial fibrillation (AF) increases by fivefold a patient's risk for thromboembolic stroke. The main source of emboli in AF is the left atrial appendage (LAA). Therefore, LAA closure could reduce the risk for thromboembolic events in AF. The investigators report the first United States experience with a novel percutaneous LAA closure device, the Lariat snare device, and its outcomes in 21 patients with AF, CHADS2 scores ≥2, and contraindications to anticoagulation. The LAA was closed with a snare containing suture from within the pericardial space. The intraoperative success of the procedure was confirmed by left atrial angiography and transesophageal echocardiographic color Doppler flow. The effectiveness of the procedure was evaluated by follow-up transesophageal echocardiography. The incidence of periprocedural and short-term complications was assessed by reviewing medical records. Twenty patients (100%) had successful LAA exclusion that was preserved at 96 ± 77 days. No patient had a stroke during an average of 352 ± 143 days of follow-up. One patient had right ventricular perforation and tamponade that required surgical exploration and repair. Two patients required prolonged hospitalization: 1 because of pericardial effusion that required repeat pericardiocentesis and 1 because of noncardiac co-morbidities. Three patients developed pericarditis <1 month after the procedure, of whom 1had associated pericardial effusion that required drainage. In conclusion, percutaneous LAA exclusion can be achieved successfully and with an acceptable incidence of periprocedural and short-term complications. Further studies are needed to determine whether LAA exclusion lowers the long-term risk for thromboembolic events in patients with AF and contraindications to anticoagulation.

Prospective Clinical Study of a Novel Left Atrial Appendage Occlusion Device

This Food and Drug Administration-approved investigational device exempt trial assessed the safety and efficacy of a novel device for external left atrial appendage (LAA) exclusion. Delivery tool and implant consisting of connectors imbedded in a compliant, soft silicone applied to the base of the LAA flush with the external wall was assessed. Patients in this prospective, multicenter trial were undergoing elective, nonendoscopic cardiac operations. A core laboratory independently assessed all intraprocedural and 90-day transesophageal echocardiograms. Sixty patients (37 men), aged 33 to 86 years, enrolled. The mean LAA application time was 27 seconds. Transesophageal echocardiograms at 90 days were available in 54 patients, and no leaks were detected. The residual LAA cavity exceeded 6 mm in 5 patients. One delivery device failed to close, and an adjunctive suture was required to complete LAA exclusion. One patient required adjunct sutures at a small tear site related to manual manipulation after fastener application. The study demonstrated safety and efficacy of this LAA exclusion device, offering an alternative to manual suturing or staples with or without reinforcement.

Left atrial appendage exclusion: State‐of‐the‐art

It is postulated that the source of thromboembolism in 90% of patients with non-valvular atrial fibrillation (AF) arises from the left atrial appendage (LAA). Anticoagulation with warfarin is the standard medical therapy for stroke prevention in patients with AF. However, chronic warfarin therapy is contraindicated in 14 to 44% of patients with AF who are at risk for stroke. Mechanical exclusion of the LAA may prevent thrombus formation in the appendage and hence reduce the risk of stroke. Recently, several studies of percutaneous transcatheter delivery of dedicated LAA exclusion devices such as the PLAATO device, Watchman device and the Amplatzer cardiac plug, have shown encouraging results as an alternative to warfarin therapy for selected patients. This article aims to review the current evidence for LAA exclusion in patients with AF.

P2-43: Pre-procedural 3D CT imaging of the left atrial appendage: Implications for the selection and deployment of left atrial appendage exclusion devices

Left atrial appendage exclusion devices may offer an alternative to standard therapy in AF patients with contraindications to anticoagulation. Currently, intra-procedural trans-esophageal echocardiography (TEE) and fluoroscopy are used to visualize the anatomy of the left atrial appendage and guide selection and placement of the device. This technique is limited in that the 2D representation of these structures may introduce error into the estimation of the orifice size and that TEE often requires general anesthesia.