Amplatzer Amulet Left Atrial Appendage Occluder Versus Watchman Device for Stroke Prophylaxis (Amulet IDE): A Randomized, Controlled Trial

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

BACKGROUND

The 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.

OBJECTIVES

This 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.

METHODS

The 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.

RESULTS

The 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.

CONCLUSIONS

The preclinical and early clinical results demonstrate a promising safety and efficacy profile for the Laminar LAA exclusion device.

Impact of Preprocedural Computed Tomography on Left Atrial Appendage Closure Success: A Swiss-Apero Trial Subanalysis

BACKGROUND

The benefit related to the use of preprocedural computed tomography angiography (CCTA) on top of periprocedural echocardiography to plan percutaneous left atrial appendage closure (LAAC) procedures is still unclear.

OBJECTIVES

The authors sought to evaluate the impact of preprocedural CCTA on LAAC procedural success.

METHODS

In the investigator-initiated SWISS-APERO (Comparison of Amplatzer Amulet and Watchman Device in Patients Undergoing Left Atrial Appendage Closure) trial, patients undergoing echocardiography-guided LAAC were randomly assigned to receive the Amulet (Abbott) or Watchman 2.5/FLX (Boston Scientific) device across 8 European centers. According to the study protocol ongoing at the time of the procedure, the first operators had (CCTA unblinded group) or did not have (CCTA blinded group) access to preprocedural CCTA images. In this post hoc analysis, we compared blinded vs unblinded procedures in terms of procedural success defined as complete left atrial appendage occlusion as evaluated at the end of LAAC (short-term) or at the 45-day follow-up (long-term) without procedural-related complications.

RESULTS

Among 219 LAACs preceded by CCTA, 92 (42.1%) and 127 (57.9%) were assigned to the CCTA unblinded and blinded group, respectively. After adjusting for confounders, operator unblinding to preprocedural CCTA remained associated with a higher rate of short-term procedural success (93.5% vs 81.1%; P = 0.009; adjusted OR: 2.76; 95% CI: 1.05-7.29; P = 0.040) and long-term procedural success (83.7% vs 72.4%; P = 0.050; adjusted OR: 2.12; 95% CI: 1.03-4.35; P = 0.041).

CONCLUSIONS

In a prospective multicenter cohort of clinically indicated echocardiography-guided LAACs, unblinding of the first operators to preprocedural CCTA images was independently associated with a higher rate of both short- and long-term procedural success. Further studies are needed to better evaluate the impact of preprocedural CCTA on clinical outcomes.

SCAI/HRS Expert Consensus Statement on Transcatheter Left Atrial Appendage Closure

Exclusion of the left atrial appendage to reduce thromboembolic risk related to atrial fibrillation was first performed surgically in 1949. Over the past 2 decades, the field of transcatheter endovascular left atrial appendage closure (LAAC) has rapidly expanded, with a myriad of devices approved or in clinical development. The number of LAAC procedures performed in the United States and worldwide has increased exponentially since the Food and Drug Administration approval of the WATCHMAN (Boston Scientific) device in 2015. The Society for Cardiovascular Angiography & Interventions (SCAI) has previously published statements in 2015 and 2016 providing societal overview of the technology and institutional and operator requirements for LAAC. Since then, results from several important clinical trials and registries have been published, technical expertise and clinical practice have matured over time, and the device and imaging technologies have evolved. Therefore, SCAI prioritized the development of an updated consensus statement to provide recommendations on contemporary, evidence-based best practices for transcatheter LAAC focusing on endovascular devices.

Impact of left atrial appendage occlusion device position on potential determinants of device-related thrombus: a patient-specific in silico study

BACKGROUND

Device-related thrombus (DRT) after left atrial appendage occlusion (LAAO) is potentially linked to adverse events. Although clinical reports suggest an effect of the device type and position on the DRT risk, in-depth studies of its mechanistic basis are needed. This in silico study aimed to assess the impact of the position of non-pacifier (Watchman) and pacifier (Amulet) LAAO devices on surrogate markers of DRT risk.

METHODS

The LAAO devices were modeled with precise geometry and virtually implanted in different positions into a patient-specific left atrium. Using computational fluid dynamics, the following values were quantified: residual blood, wall shear stress (WSS) and endothelial cell activation potential (ECAP).

RESULTS

In comparison to an ostium-fitted device position, deep implantation led to more residual blood, lower average WSS and higher ECAP surrounding the device, especially on the device's atrial surface and the surrounding tissue, suggesting increased risk for potential thrombus. For the non-pacifier device, an off-axis device orientation resulted in even more residual blood, higher ECAP and similar average WSS as compared to an ostium-fitted device position. Overall, the pacifier device showed less residual blood, higher average WSS and lower ECAP, compared to the non-pacifier device.

CONCLUSIONS

In this in silico study, both LAAO device type and implant position showed an impact on potential markers of DRT in terms of blood stasis, platelet adhesion and endothelial dysfunction. Our results present a mechanistic basis for clinically observed risk factors of DRT and the proposed in silico model may aid in the optimization of device development and procedural aspects.

Left Atrial Appendage Occlusion Strengths and Weaknesses of the Lobe-Only Occluder Concept in Theory and in Practice

Left atrial appendage closure aims to eliminate the stasis component of Virchow triad by eliminating a cul-de-sac that favors thrombosis, particularly when atrial contractility becomes inefficient, such as in atrial fibrillation. Left atrial appendage closure devices have a common objective of sealing the appendage completely, with device stability and avoidance of device thrombosis. Two main device designs have been used to perform left atrial appendage closure: those that use a pacifier design (lobe + disk) and those that use a plug (single lobe) design. This review highlights the potential features and benefits of the single-lobe devices.

Are Ischemic Strokes the Same? The Special Case Argument of Atrial Fibrillation

A comprehensive evaluation is necessary to identify the etiologic factors in order to select optimal stroke-prevention measures. Atrial fibrillation is one of the most important stroke causes. Although anticoagulant therapy is the treatment of choice for patients with nonvalvular atrial fibrillation, it should not be considered uniformly to treat all patients given the high mortality associated with anticoagulant-related hemorrhages. The authors propose a risk-stratified individualized approach for stroke prevention in patients with nonvalvular atrial fibrillation by considering nonpharmacologic approaches for patients at high hemorrhage risk or otherwise unsuitable for lifelong anticoagulation.

The Future of LAAC-In 5, 10, and 20 Years

Early experience with percutaneous LAA closure documented complication rates of ∼10%, with failure to implant devices in ∼10% of patients. These numbers are unrecognizable in contemporary practice due to the iterative changes made largely in the last 10 years. Here we look forward to ask what might change, and when, to bring percutaneous LAA closure out of the niche early adopter centers into routine use. We consider the opportunity to incorporate different technologies into LAAc devices in the context of managing patient with atrial fibrillation. Finally, we consider how to make the procedure safer and more effective.

The Strengths and Weaknesses of the LAA Covering Disc Occluders-Conceptually and in Practice

Endocardial left atrial appendage (LAA) occluders with a covering disc encompass a wide range of devices that share the common feature of a distal anchoring "body" and proximal covering "disc" design. This unique design feature has potential advantages in certain complex LAA anatomies and challenging clinical scenarios. The current review article summarizes the different features of established and novel devices, preprocedural imaging updates, intraprocedural technical considerations, and postprocedural follow-up issues specific to this category of LAA occluders.

Leap or lag: left atrial appendage closure and guidelines

Atrial fibrillation (AF) is associated with life-threatening thromboembolism. Most emboli stem from thrombosis in the left atrial appendage (LAA). The current treatment of choice is oral anticoagulants (OACs), but a small proportion of patients cannot take OACs predominantly because of the so-called unacceptable bleeding risks. However, many who initially accept OACs subsequently stop therapy or reduce the OAC treatment to a potentially non-effective dose leaving them exposed to thromboembolic risk. A relatively simple alternative therapy involves the catheter-based insertion of a LAA closure (LAAC) device to prevent thromboembolism from the LAA. There is a considerable evidence base for this therapy consisting of clinical trials and observational data which suggests comparable therapeutic efficacy with a possible small excess of ischaemic strokes. Although LAAC has been very closely examined by regulators and approved for market release, guidelines from most professional societies give only weak recommendations for use of this device which may be the only known effective therapy available to some at-risk AF patients. Guidance materials from the same societies more enthusiastically endorse LAAC. Clinical practice is running well ahead of the guidelines because equipoise has been lost by physicians faced with patients for whom they have no other effective therapy. Guideline writers are correct in providing recommendations which are less strong for LAAC than for OACs, for those who are able and willing to take OAC treatment, but for those who are not, a stronger recommendation is needed. But, should the guidelines lag behind or leap ahead of the available evidence?

The WATCHMAN Device Review: A New Era for Stroke Prophylaxis

Atrial fibrillation (AF) is a major risk factor for ischemic stroke, accounting for more than 37 million cases worldwide. In AF, the left atrial appendage (LAA) is the most common site of thrombus formation, and its ligation/closure with the WATCHMAN device is a good alternative to long-term oral anticoagulation, especially in patients with contraindications to warfarin. However, the implantation procedure is associated with various risks and complications. A short-term anticoagulant and antithrombotic administration are essential after implantation. However, no consensus has been reached on the optimal regimen. The WATCHMAN device is non-inferior to warfarin and is a safe alternative for the prevention of stroke and systemic embolization related to non-valvular atrial fibrillation (NVAF). Important procedure-related complications include pericardial effusion (PE), device embolization, procedure-related ischemic stroke, and device-related thrombosis (DRT) formation. It is essential to optimize post-implantation therapy according to individual patient bleeding risk, DRT formation, and contraindication to direct oral anticoagulants (DOACs). Recent studies have also shown that DOACs are a convenient and non-inferior substitute for warfarin. Furthermore, patients with absolute contraindications to OACs/DOACs can only be managed with dual antiplatelet therapy (DAPT). Transesophageal echocardiography (TEE) should be used to assess residual peridevice flow and possible DRT formation at days 45 and 12 months. Low molecular weight heparin (LMWH) and OAC are excellent choices for DRT treatment if detected. This review summarizes the most important complications of the WATCHMAN device in the existing literature and discusses various anticoagulation strategies and challenges post-implementation.

SCAI/HRS Expert Consensus Statement on Transcatheter Left Atrial Appendage Closure

Exclusion of the left atrial appendage to reduce thromboembolic risk related to atrial fibrillation was first performed surgically in 1949. Over the past 2 decades, the field of transcatheter endovascular left atrial appendage closure (LAAC) has rapidly expanded, with a myriad of devices approved or in clinical development. The number of LAAC procedures performed in the United States and worldwide has increased exponentially since the Food and Drug Administration approval of the WATCHMAN (Boston Scientific) device in 2015. The Society for Cardiovascular Angiography & Interventions (SCAI) has previously published statements in 2015 and 2016 providing societal overview of the technology and institutional and operator requirements for LAAC. Since then, results from several important clinical trials and registries have been published, technical expertise and clinical practice have matured over time, and the device and imaging technologies have evolved. Therefore, SCAI prioritized the development of an updated consensus statement to provide recommendations on contemporary, evidence-based best practices for transcatheter LAAC focusing on endovascular devices.

Appropriate Use Criteria of Left Atrial Appendage Closure Devices: Latest Evidences

Atrial fibrillation is the most common arrythmia and it is linked to an increased risk of stroke. Even if anticoagulation therapy reduces the rate of stroke the benefits of this therapy have to been balanced with the increased risk of hemorrhagic event. Left atrial appendage closure is a valid alternative to long term anticoagulation in patients with atrial fibrillation and high hemorrhagic risk. Actually new devices with different features have been tested and introduced progressively in the clinical practice. Improvements preprocedural imaging evaluation and the learning curve of the operators led to percutaneous left atrial appendage closure a safe and effective procedure. A good knowledge of different devices and the technique of implant is necessary for optimization percutaneous left atrial appendage closure and the reduction of complications during the acute phase and follow up.

Antithrombotic Management After Left Atrial Appendage Closure: Current Evidence and Future Perspectives

Left atrial appendage closure is an alternative to chronic oral anticoagulation to prevent embolic events related to nonvalvular atrial fibrillation. After device implantation, antithrombotic treatment is prescribed to prevent device-related thrombosis, a dreadful complication associated with an increased risk of ischemic events. However, the optimal antithrombotic treatment after left atrial appendage closure, effective on both device-related thrombus prevention and bleeding risk mitigation, remains to be determined. In more than 10 years experience with left atrial appendage closure, a wide range of antithrombotic treatments have been used, mostly in observational studies. In this review, we analyzed the body of evidence for each antithrombotic regimen after left atrial appendage closure to provide tools to guide the physician choice and describe future perspectives in the field.

SCAI/HRS expert consensus statement on transcatheter left atrial appendage closure

Exclusion of the left atrial appendage to reduce thromboembolic risk related to atrial fibrillation was first performed surgically in 1949. Over the past 2 decades, the field of transcatheter endovascular left atrial appendage closure (LAAC) has rapidly expanded, with a myriad of devices approved or in clinical development. The number of LAAC procedures performed in the United States and worldwide has increased exponentially since the Food and Drug Administration approval of the WATCHMAN (Boston Scientific) device in 2015. The Society for Cardiovascular Angiography & Interventions (SCAI) has previously published statements in 2015 and 2016 providing societal overview of the technology and institutional and operator requirements for LAAC. Since then, results from several important clinical trials and registries have been published, technical expertise and clinical practice have matured over time, and the device and imaging technologies have evolved. Therefore, SCAI prioritized the development of an updated consensus statement to provide recommendations on contemporary, evidence-based best practices for transcatheter LAAC focusing on endovascular devices.

Indications, evidence, and controversy in the closure of the left atrial appendage

Closure of the left atrial appendage (LAAO) represents a valid option for the prevention of cardio-embolic stroke in patients with atrial fibrillation (AF) at high bleeding risk. Previous studies had shown that the atrial appendage represents the site of atrial thrombus formation in about 90% of cases in the presence of non-valvular AF. In all patients with AF and higher thromboembolic risk (in particular with CHA2DS2VASc score ≥2 in women and ≥1 in men) there is an indication for thromboembolic prophylaxis with AOC (oral anti-coagulants). The main guidelines and international consensus documents place the indication for the LAAO in patients with the need for thromboembolic prophylaxis who have contraindications to oral anticoagulant therapy (class of recommendation IIb).

Diagnosis and Management of Cardioembolic Stroke

OBJECTIVE

Cardioembolic stroke accounts for nearly 30% of ischemic strokes. Prompt diagnosis of the underlying mechanism may improve secondary prevention strategies. This article reviews recent randomized trials, observational studies, case reports, and guidelines on the diagnosis and treatment of cardioembolic stroke.

LATEST DEVELOPMENTS

Several pathologies can lead to cardioembolic stroke, including atrial fibrillation, aortic arch atheroma, patent foramen ovale, left ventricular dysfunction, and many others. Secondary stroke prevention strategies differ across these heterogeneous mechanisms. In addition to medical treatment advances such as the use of direct oral anticoagulants in patients with atrial fibrillation, surgical treatments such as closure of patent foramen ovale have been shown to reduce the risk of recurrent stroke in select patients. Furthermore, left atrial appendage occlusion is a promising strategy for patients with atrial fibrillation who are candidates for short-term oral anticoagulation therapy but not long-term oral anticoagulation therapy.

ESSENTIAL POINTS

A thorough diagnostic evaluation is essential to determine cardioembolic causes of stroke. In addition to risk factor management and lifestyle modifications, identification and targeting of the underlying cardioembolic stroke mechanisms will lead to improved stroke prevention strategies in patients with cardioembolic stroke.

Pediatric Ischemic Stroke

OBJECTIVE

Pediatric cerebrovascular disease is one of the leading causes of death and disability in children. Survivors of childhood stroke and their families are often left to cope with long-lasting sequelae, such as barriers to school reentry and long-term challenges in attaining independence as adults. Because childhood stroke is rare and providers may not be familiar with the disorder, this article reviews the risk factors, acute management, and sequelae of ischemic stroke in children.

LATEST DEVELOPMENTS

High-quality evidence has resulted in an organized approach to emergent treatment of ischemic stroke in adults, but most front-line providers are less prepared for emergent stroke management in children. The level of evidence for reperfusion therapies in children remains low but is growing. Thrombolysis and thrombectomy are sometimes considered for hyperacute treatment of stroke in children. Readiness for pediatric stroke at regional centers should include an organized approach to pediatric stroke triage and management based on extrapolation from adult stroke trials, expert consensus, and emerging pediatric studies.

ESSENTIAL POINTS

This review provides up-to-date information about ischemic stroke risk factors and management in children. Preparation for rapid stroke diagnosis and management in children may improve outcomes.

Peridevice Leak After Left Atrial Appendage Occlusion: Incidence, Mechanisms, Clinical Impact, and Management

Left atrial appendage occlusion is an increasingly adopted stroke prevention strategy in patients with atrial fibrillation. However, peridevice leaks after the procedure are not infrequent and have recently been shown to confer a higher risk for subsequent ischemic events. In this paper, the authors review the available research on the frequency, mechanisms, clinical significance, and management of peridevice leak after percutaneous left atrial appendage occlusion.

Atrial fibrillation: Primary prevention, secondary prevention, and prevention of thromboembolic complications: Part 2

Atrial fibrillation (AF), the most common sustained cardiac arrhythmia, once thought to be benign as long as the ventricular rate was controlled, is associated with significant cardiac morbidity and mortality. Increasing life expectancy driven by improved health care and decreased fertility rates has, in most of the world, resulted in the population aged ≥65 years growing more rapidly than the overall population. As the population ages, projections suggest that the burden of AF may increase more than 60% by 2050. Although considerable progress has been made in the treatment and management of AF, primary prevention, secondary prevention, and prevention of thromboembolic complications remain a work in progress. This narrative review was facilitated by a search of MEDLINE to identify peer-reviewed clinical trials, randomized controlled trials, meta-analyses, and other clinically relevant studies. The search was limited to English-language reports published between 1950 and 2021. Atrial fibrillation was searched using the terms primary prevention, hyperthyroidism, Wolff-Parkinson-White syndrome, catheter ablation, surgical ablation, hybrid ablation, stroke prevention, anticoagulation, left atrial occlusion and atrial excision. Google and Google scholar as well as bibliographies of identified articles were reviewed for additional references. In these two manuscripts, we discuss the current strategies available to prevent AF, then compare non-invasive and invasive treatment strategies to diminish AF recurrence. In addition, we examine the pharmacological, percutaneous device and surgical approaches to prevent stroke as well as other types of thromboembolic events.

Left atrial appendage sealing performance of the Amplatzer Amulet and Watchman FLX device

BACKGROUND

The left atrial appendage (LAA) sealing properties of the Amplatzer Amulet and Watchman FLX devices were compared using cardiac computed tomography (CT) follow-up.

METHODS

Single-center cohort study of patients undergoing LAAO between 2017 and 2020. Two consecutive cohorts were enrolled, one treated with the Amplatzer Amulet (n = 150) up till 2019, and a second cohort treated with the Watchman FLX (n = 150) device from 2019. Cardiac CT was performed 2 months postprocedure. The primary outcome was complete LAA occlusion defined as no visible peri-device leak (PDL) and absence of contrast patency in the distal LAA. Secondary outcomes included PDL, contrast patency without visible PDL, PDL area, and periprocedural complications.

RESULTS

Complete occlusion was achieved in 39 (30.5%) of the Amulet group, compared to 89 (71.8%) of the FLX group, p < 0.001. A PDL at the Amulet disc was present in 65 (50.8%), at the lobe in 16 (12.5%), and at both the disc and lobe in 13 (10.2%). For FLX, a PDL was present in 20 (16.1%). Contrast patency without visible PDL was observed in 24 (18.8%) and 15 (12.1%) of the Amulet and FLX group, respectively. The PDL area at the Amulet mid-lobe was 92 mm² (59-158) and 32 mm² (IQR 28-96) for FLX, p = 0.019. Device-related thrombosis occurred in 1 (0.7%) and 2 (1.3%), respectively (p = 0.99), with periprocedural adverse events occurring in 6 (4%) and 8 (5.3%) of the Amulet and FLX group (p = 0.79).

CONCLUSION

Complete LAA occlusion was achieved in a significantly higher proportion treated with the Watchman FLX compared to the Amulet device. PDL was smaller with the FLX than the Amulet. Conceptual device design differences make interpretation of results complex, and additional studies with clinical outcomes are needed.

'Just the two of us': single-operator interventional left atrial appendage closure-a case report

Background

Different procedural strategies have been published targeting to facilitate transcatheter left atrial appendage closure (LAAc). We demonstrate feasibility of a procedural set-up allowing single-operator LAAc in a selected patient.

Case summary

A 87-year-old male with persistent Afib (CHA²DS²VASc, five; HASBLED, three) was referred to our hospital for LAAc. Pre-procedural planning and device sizing with three-dimensional transesophageal echocardiography (3DTEE) confirmed a non-complex anatomy of the essential anatomical structures predicting suitability for LAAc. Therefore, the procedure was performed with a simplified single-operator interventional approach. Intraprocedural TEE guidance, device preparation, and LAAc were accomplished by the interventionalist himself. For procedural guidance, the TEE probe was arranged and handled in a technique comparable to the use of intracardiac echocardiography (ICE). Procedure time (skin-to-skin) was 21 min, left atrial access time 9 min, and fluoroscopy time was 4:28 min without the use of contrast dye. The patient was discharged the following day in good medical conditions.

Discussion

To the best of our knowledge, this is the first report on successful single-operator LAAc in a selected patient. The intervention, pre-procedural screening, and intraprocedural 3D TEE were performed by one single experienced interventionalist. This simplified technique is based on a standardized pre-procedural imaging-protocol with 3D echocardiography. According to our experience, this streamlined approach is a valuable option in non-complex LAAc cases. In the growing field of structural cardiac interventions, this approach might be an interesting option for centres with limited personal and technical resources.

Foam-based Left Atrial Appendage Closure (CLAAS) Device: Evaluation in a Chronic Canine Model

Background

The Conformal Left Atrial Appendage System (CLAAS) is a transcatheter implant designed to occlude the left atrial appendage to prevent stroke in patients with nonvalvular atrial fibrillation. The implant incorporates a novel polyurethane polycarbonate-urea foam matrix to enhance device performance. The objective of this study was to characterize the thrombogenicity, sealing, implant integrity, local tissue response, and systemic toxicity of the implant in a healthy canine model.

Methods

Devices were evaluated in a chronic canine model using echocardiographic and fluoroscopic guidance (n = 8). Postprocedural echocardiographic evaluation was performed at case completion and at 2, 45, 90, and 150 days. Animals were sacrificed at 90 (n = 4) and 150 (n = 4) days. Necropsy included gross, x-ray, and histologic examination.

Results

CLAAS implants were implanted in all animals successfully on the basis of fluoroscopic, intracardiac echo, and transthoracic echo criteria. Although 2 animals were noted to have leaks (1 at implantation and 1 at day 90 post procedure before sacrifice), both were of <5 mm. All left atrial appendages were completely sealed on gross examination. No device-related thrombus, pericardial effusion, or evidence of distal organ emboli was observed. All implants maintained their structural integrity and were well integrated within the tissue. There was no histologic evidence of toxicity noted in the downstream organs or tissues.

Conclusions

The CLAAS implant can be deployed providing a good seal for up to 150 days without signs of local or systemic toxicity in a canine model.

Left atrial appendage occlusion

Prevention of stroke represents a goal of primary importance in health systems due to its associated morbidity and mortality. As several patient groups with increased stroke rates have been identified, multiple approaches have been developed and implemented: oral anticoagulation (OAC) for patients with atrial fibrillation, surgical and percutaneous revascularisation in patients with carotid disease, device closure for patients with patent foramen ovale, and now, left atrial appendage occlusion (LAAO) for selected patients with non-valvular atrial fibrillation (NVAF). The latter group of patients are the focus of this review which evaluates the pathophysiology, selection of patients, procedural performance, outcomes of treatment both during and post-procedure, adjunctive therapy, complications, and longer-term outcomes.

Real-world clinical outcomes with a next-generation left atrial appendage closure device: the FLXibility Post-Approval Study

AIMS

The FLXibility Post-Approval Study collected data on unselected patients implanted with a WATCHMAN FLX in a commercial clinical setting.

METHODS AND RESULTS

Patients were implanted with a WATCHMAN FLX per local standard of care, with a subsequent first follow-up visit from 45 to 120 days post-implant and a final follow-up at 1-year post-procedure. A Clinical Event Committee adjudicated all major adverse events and TEE/CT imaging results were adjudicated by a core laboratory. Among 300 patients enrolled at 17 centres in Europe, the mean age was 74.6 ± 8.0 years, mean CHA2DS2-VASc score was 4.3 ± 1.6, and 62.1% were male. The device was successfully implanted in 99.0% (297/300) of patients. The post-implant medication regimen was DAPT for 87.3% (262/300). At first follow-up, core-lab adjudicated complete seal was 88.2% (149/169), 9.5% (16/169) had leak <3 mm, 2.4 (4/169) had leak ≥3 mm to ≤5 mm, and 0% had >5 mm leak. At 1 year, 93.3% (280/300) had final follow-up; 60.5% of patients were on a single antiplatelet medication, 21.4% were on DAPT, 5.6% were on direct oral anticoagulation, and 12.1% were not taking any antiplatelet/anticoagulation medication. Adverse event rates through 1 year were: all-cause death 10.8% (32/295); CV/unexplained death 5.1% (15/295); disabling and non-disabling stroke each 1.0% (3/295, all non-fatal); pericardial effusion requiring surgery or pericardiocentesis 1.0% (3/295); and device-related thrombus 2.4% (7/295).

CONCLUSION

The WATCHMAN FLX device had excellent procedural success rates, high LAA seal rates, and low rates of thromboembolic events in everyday clinical practice.

Impact of Computational Modeling on Transcatheter Left Atrial Appendage Closure Efficiency and Outcomes

BACKGROUND

When performing transcatheter left atrial appendage (LAA) closure, peridevice leaks and device-related thrombus (DRT) have been associated with worse clinical outcomes-hence, their risk should be mitigated.

OBJECTIVES

The authors sought to assess whether use of preprocedural computational modeling impacts procedural efficiency and outcomes of transcatheter LAA closure.

METHODS

The PREDICT-LAA trial (NCT04180605) is a prospective, multicenter, randomized trial in which 200 patients were 1:1 randomized to standard planning vs cardiac computed tomography (CT) simulation-based planning of LAA closure with Amplatzer Amulet. The artificial intelligence-enabled CT-based anatomical analyses and computer simulations were provided by FEops (Belgium).

RESULTS

All patients had a preprocedural cardiac CT, 197 patients underwent LAA closure, and 181 of these patients had a postprocedural CT scan (standard, n = 91; CT + simulation, n = 90). The composite primary endpoint, defined as contrast leakage distal of the Amulet lobe and/or presence of DRT, was observed in 41.8% in the standard group vs 28.9% in the CT + simulation group (relative risk [RR]: 0.69; 95% CI: 0.46-1.04; P = 0.08). Complete LAA closure with no residual leak and no disc retraction into the LAA was observed in 44.0% vs 61.1%, respectively (RR: 1.44; 95% CI: 1.05-1.98; P = 0.03). In addition, use of computer simulations resulted in improved procedural efficiency with use of fewer Amulet devices (103 vs 118; P < 0.001) and fewer device repositionings (104 vs 195; P < 0.001) in the CT + simulation group.

CONCLUSIONS

The PREDICT-LAA trial demonstrates the possible added value of artificial intelligence-enabled, CT-based computational modeling when planning for transcatheter LAA closure, leading to improved procedural efficiency and a trend toward better procedural outcomes.

Left atrial appendage closure in patients with reversed chicken-wing morphology: Anatomical features and procedural strategy

Background

Left atrial appendage (LAA) closure (LAAC) in atrial fibrillation (AF) patients with the reversed chicken-wing (RCW) LAA is challenging.

Aims

To elucidate the LAAC strategy of the RCW-LAA.

Methods

A total of 802 AF patients who were enrolled in the LAACablation registry for LAAC procedure were included, 55 of whom presented with the RCW-LAA. The WATCHMAN device was implanted using the standard protocol when the sheath depth was no less than the device depth (the simple group). For those with a sheath depth of less than the device depth (the complex group), device deployment was attempted with acceptable protrusion or after a repeated atrial transseptal puncture (re-ATP) at a more inferior and anterior position. The anatomical and procedural features were compared between groups and before and after the re-ATP.

Results

The success rate of LAAC was significantly lower in patients with the RCW-LAA than with the other morphologies (92.7% vs. 98.8%, p = 0.001). Compared with the simple group, the complex group had shorter root depth and shorter neck length, and more LAAs in the complex group were at lower position (all p < 0.05). The sheath depth after the re-ATP was significantly greater than that before the re-ATP (18.8 ± 3.4 mm vs. 14.7 ± 2.6 mm, p < 0.001). For the patients who underwent re-ATP, the sheath went significantly deeper in successful procedures than in aborted procedures (19.7 ± 3.3 mm vs. 15.8 ± 1.8 mm, p = 0.040).

Conclusions

The anatomical features of the RCW-LAA were related to the complexity of the LAAC procedure. The re-ATP at an inferior and anterior location could increase the success rate of LAAC.

ClinicalTrialsgov

NCT03788941.

Transcatheter Left Atrial Appendage Closure

Atrial fibrillation is the most common arrhythmia worldwide, placing a large population at risk for potentially disabling ischemic strokes, yet an estimated 50% of eligible patients cannot tolerate or are contraindicated to receive oral anticoagulation. Within the last 15 years, transcatheter options for left atrial appendage closure (LAAC) have provided a valuable alternative to chronic oral anticoagulation for reducing risk of stroke and systemic embolism in patients with nonvalvular atrial fibrillation. With newer generation devices such as Watchman FLX and Amulet gaining approval from the US Food and Drug Administration in recent years, several large clinical trials have demonstrated the safety and efficacy of transcatheter LAAC in a population intolerant to systemic anticoagulation. In this contemporary review, we discuss the indications for transcatheter LAAC and the evidence evaluating the use of various device therapies currently available or in development. We also examine current unmet challenges in intraprocedural imaging and controversies in postimplantation antithrombotic regimens. Several ongoing seminal trials are hoping to clarify the role of transcatheter LAAC as a safe, first-line option for all patients with nonvalvular atrial fibrillation.

Incidence, Predictors, and Clinical Outcomes of Device-Related Thrombus in the Amulet IDE Trial

BACKGROUND

Device-related thrombus (DRT) following left atrial appendage occlusion (LAAO) can lead to adverse clinical outcomes. DRT rates and outcomes from randomized trials are limited.

OBJECTIVES

This analysis investigated the incidence, predictors, and clinical outcomes of DRT following LAAO in the Amulet IDE (AMPLATZER Amulet LAA Occluder Trial) trial.

METHODS

Successful implants occurred in 903 patients with an Amulet occluder (dual occlusive mechanism device) and 885 patients with a Watchman device (single occlusive mechanism device). These patients were then followed through 18 months and DRT was assessed by transesophageal echocardiography.

RESULTS

The overall incidence of DRT was 3.9% (n = 70) with 3.4% (n = 30) in dual occlusive mechanism device patients and 4.8% (n = 40) in single occlusive mechanism device patients. Most DRTs (n = 19 of 31) were identified early (≤45 days) on the dual occlusive mechanism device, whereas most of the DRTs (n = 31 of 42) were identified late (>45 days) on the single occlusive mechanism device. Strong predictors of DRT included atrial fibrillation at time of procedure (HR: 2.44; 95% CI: 1.42-4.22; P < 0.01), female sex (HR: 1.65; 95% CI: 1.01-2.71; P = 0.04), and older age (HR: 1.04; 95% CI: 1.01-1.08; P = 0.02). There were no stroke events following DRT in the dual occlusive mechanism device group and 3 stroke events following DRT in the single occlusive mechanism device group. Patients with DRT were at a greater risk for cardiovascular mortality compared with non-DRT patients (8.7% vs 3.9%; HR: 2.33; 95% CI: 1.01-5.39; P = 0.04).

CONCLUSIONS

Incidence of DRT following LAAO was low. Early DRTs are seen with the dual occlusive mechanism device and late DRTs are seen with the single occlusive mechanism device. Increased cardiovascular mortality risk in patients with DRT should be further investigated. (AMPLATZER Amulet LAA Occluder Trial; NCT02879448).

Impact and predictors of device-related thrombus after percutaneous left atrial appendage closure

Device-related thrombus (DRT) is a known complication occurring in up to 7% of patients undergoing percutaneous left atrial appendage closure (LAAC). Since the target population of LAAC is generally ineligible for oral anticoagulant therapies, DRT raises important concerns. The aim of this review will be to summarize available evidence on DRT after LAAC focusing on its possible impact on outcomes. Recent findings showed a tighter association between DRT and neurological ischemic events. Antithrombotic regimen adopted after LAAC may have a protective effect against DRT. Many patient-related and procedural factors have been identified as possible predictors of DRT. A tailored approach, which takes into account DRT, is needed in the patient selection for LAAC and in the postprocedural follow-up.

A fully biodegradable polydioxanone occluder for ventricle septal defect closure

Ventricular septal defect (VSD) is one of the commonest congenital heart diseases (CHDs). Current occluders for VSD treatment are mainly made of nitinol, which has the risk of nickel allergy, persistent myocardial abrasion and fatal arrythmia. Herein, a fully biodegradable polydioxanone (PDO) occluder equipped with a shape line and poly-l-lactic acid PLLA membranes is developed for VSD closure without the addition of metal marker. PDO occluder showed great mechanical strength, fatigue resistance, geometry fitness, biocompatibility and degradability. In a rat subcutaneous implantation model, PDO filaments significantly alleviated inflammation response, mitigated fibrosis and promoted endothelialization compared with nitinol. The safety and efficacy of PDO occluder were confirmed in a canine VSD model with 3-year follow-up, demonstrating the biodegradable PDO occluder could not only effectively repair VSD, induce cardiac remodeling but also address the complications associated with metal occluders. Furthermore, a pilot clinical trial with five VSD patients indicated that all the occluders were successfully implanted under the guidance of echocardiography and no adverse events occurred during the 3-month follow-up. Collectively, the fully bioresorbable PDO occluder is safe and effective for clinical VSD closure and holds great promise for the treatment of structural CHDs.

An updated meta-analysis of device related thrombus following left atrial appendage closure in patients with atrial fibrillation

Aims

Device related thrombus (DRT) is a known complication of left atrial appendage closure (LAAC). However, the relation between DRT and elevated risk of ischemic events remains controversial. This study is sought to reassessed the incidence of DRT following LAAC and the relation between DRT and elevated risk of ischemic stroke and systemic embolism (SE) with latest clinical trials included.

Methods

The PubMed, Embase, and Cochrane Library databases were systematically searched from their inception until April 2022 for studies that reported the incidence of DRT and compared the incidence of both stroke and SE between DRT patients and non-DRT patients.

Results

In 59 eligible studies, the incidence of DRT was 366/12,845 (2.8%, ranging from 0 to 11%, I ² = 64%). The incidence of DRT was not statistically different between single-seal device (SS) and dual-seal device (DS) in subgroup analysis [171/6,190 (2.8%) vs. 78/3,023 (3.6%); p = 0.93]. The pooled incidence of stroke (26 studies, 7,827 patients) in patients with and without DRT was 11.5% in DRT patients and 2.9% among non-DRT patients (OR: 5.08; 95% CI = 3.47-7.44). In the sensitivity analysis, DRT was associated with higher rate of stroke (12.1 vs. 3.2%; OR: 4.14; 95% CI = 2.69-6.38) and SE (16.0 vs. 3.8%; OR: 4.48; 95% CI = 3.04-6.62).

Conclusion

The incidence of DRT was low and similar between SS and DS devices. DRT was associated with increased rates of ischemic events. The occurrence rate of ischemic events associated DRT was comparable between two occlusion mechanism devices.

Systematic review registration

[https://www.crd.york.ac.uk/], identifier [CRD42022326179].

Left Atrial Appendage Occlusion: Current Advances and Remaining Challenges

The field of left atrial appendage occlusion is rapidly evolving. However, several issues remain including the limited randomized efficacy data, peri-device leak, device-related thrombus, and the ongoing refinement of procedural techniques. In this article, we provide a contemporary overview of left atrial appendage occlusion focusing on 4 key remaining challenges: efficacy data, peri-device leak, device-related thrombus, and procedural optimization.

Device-Sizing and Associated Complications With Left Atrial Appendage Occlusion: Findings From the NCDR LAAO Registry

BACKGROUND

Left atrial appendage occlusion is an important alternative to anticoagulation in select patients with nonvalvular atrial fibrillation. Trends in real-world device sizing and associated short-term complications have not been characterized.

METHODS

Using the National Cardiovascular Data Left Atrial Appendage Occlusion (NCDR LAAO) Registry, patients who underwent left atrial appendage occlusion with a Watchman 2.5 device from January 1, 2016, to June 30, 2020, were identified. Patients were stratified by device size based on left atrial appendage orifice size, and categorized as receiving a device that was undersized, oversized, or per manufacturer recommendation. Relationships between device sizing and short-term outcomes, including pericardial effusion, device embolism, and significant leak, were assessed.

RESULTS

Of the 68 456 patients, 6539 (10.5%) of patients received undersized devices, 17 791 (26.0%) according to manufacturer recommendations, and 44 126 (64.4%) received an oversized device. The 27-mm device was most commonly deployed [21 736 (31.8%)], whereas the smallest and largest devices (21 and 33 mm) were least commonly deployed [7695 (11.2%) and 9077 (13.3%), respectively]. Compared with manufacturer recommended sizing, there was no difference in the odds of pericardial effusion for either undersized (1.048 [95% CI' 0.801-1.372]; P=0.733) or oversized (1.101 [95% CI' 0.933-1.298]; P=0.254) devices. Similarly, relative to manufacturer recommended sizing, the odds of a composite adverse outcome of device migration or embolization and significant peridevice leak at 45 days were similar among undersized devices (1.030 [95% CI' 0.735-1.444]; P=0.863) and favorable for oversized devices (0.701 [95% CI' 0.561-0.876]; P=0.002) devices, primarily driven by lower odds of leak. Selection of oversized devices increased significantly over the study period (from 60.3% in 2016 to 66.0% in 2020; P<0.001).

CONCLUSIONS

Among patients undergoing left atrial appendage occlusion with the first-generation Watchman device, receipt of oversized devices was common and increased over time. The high prevalence of oversizing was associated with lower odds of significant leak or device embolization without increased odds of other adverse events.

Der interventionelle Vorhofohrverschluss: eine Alternative zur oralen Antikoagulation

Die orale Antikoagulation ist der Standard zur Prävention von Embolien bei Patienten mit Vorhofflimmern. Der interventionelle Vorhofohrverschluss ist eine Alternative zur oralen Antikoagulation bei Patienten mit Vorhofflimmern und Kontraindikationen oder Unverträglichkeiten einer oralen Antikoagulation, insbesondere bei klinisch relevanten Blutungen. Die Sicherheit des Verfahrens hat in den letzten Jahren erheblich zugenommen. Mehrere große randomisierte Studien vergleichen aktuell die Effektivität und Sicherheit der oralen Antikoagulation und des interventionellen Vorhofohrverschlusses.

Clinical efficacy and safety comparison of Watchman device versus ACP/Amulet device for percutaneous left atrial appendage closure in patients with nonvalvular atrial fibrillation: A study-level meta-analysis of clinical trials

Left atrial appendage occlusion is not inferior to oral anticoagulants in the prevention of stroke in several randomized controlled trials. However, the clinical efficacy and safety comparison of the Watchman and amplatzer cardiac plug (ACP)/Amulet devices for percutaneous left atrial appendage closure (LAAC) in patients with non-valvular atrial fibrillation was controversial. A database search was conducted using PubMed, EMBASE, Cochrane Library, and Clinicaltrials.gov for trials that compared Watchman device vs ACP/Amulet device. The effective outcomes were stroke and systemic embolism. Safety outcomes were all-cause death, cardiovascular death, and major bleeding. Device-related complications included device-related thrombus (DRT), peri-device leaks (PDL > 5 mm). A total of 19 articles involving 6224 patients were included in the present study. The Watchman and ACP/Amulet groups comprised 3267 and 2957 patients, respectively. No statistically significant differences were detected in the stroke (odd ratio [OR]:1.24, 95% confidence interval [CI]: 0.92-1.67, p = .17, I²  = 0), systemic embolism (OR:1.10, 95% CI: 0.51-2.35, p = .81, I²  = 0%), all-cause death (OR:0.97, 95% CI: 0.80-1.18, p = .77, I²  = 1%), cardiogenic death (OR:0.99, 95% CI: 0.77-1.29, p = .96, I²  = 0%), major bleeding (OR:1.18, 95% CI: 0.98-1.43, p = .08, I²  = 25%). DRT (OR:1.48, 95% CI: 1.06-2.06, p = .02, I²  = 0%) and PDL > 5 mm (OR:2.57, 95% CI: 1.63-4.04, p < .0001, I²  = 0%) were significantly lower in ACP/Amulet group compared to Watchman group. The effective and safety outcomes were comparable between two groups. ACP/Amulet group had significantly lower rates of DRT and PDL > 5 mm than Watchman group.

Cardiac computed tomography following Watchman FLX implantation: device-related thrombus or device healing?

AIMS

Cardiac computed tomography (CT) is increasingly utilized during follow-up after left atrial appendage closure (LAAC). Hypoattenuated thickening (HAT) is a common finding and might represent either benign device healing or device-related thrombosis (DRT). The appearance and characteristics of HAT associated with the Watchman FLX have not been previously described. Therefore, we sought to investigate cardiac CT findings during follow-up after Watchman FLX implantation with a focus on HAT and DRT.

METHODS AND RESULTS

Retrospective single-centre, observational study including all patients with successful Watchman FLX implantation and follow-up cardiac CT between March 2019 and September 2021 (n = 244). Blinded analysis of CT images was performed describing the localization, extent, and morphology of HAT and correlated to imaging and histology findings in a canine model. Relevant clinical and preclinical ethical approvals were obtained.Overall, HAT was present in 156 cases (64%) and could be classified as either subfabric hypoattenuation (n = 59), flat sessile HAT (n = 78), protruding sessile HAT (n = 16), or pedunculated HAT (n = 3). All cases of pedunculated HAT and five cases of protruding sessile HAT were considered as high-grade HAT (n = 7). Subfabric hypoattenuation and flat sessile HAT correlated with device healing and endothelialization in histological analysis of explanted devices.

CONCLUSION

Subfabric hypoattenuation and flat sessile HAT are frequent CT findings for Watchman FLX, likely representing benign device healing and endothelialization. Pedunculated HAT and protruding HAT are infrequent CT findings that might represent DRT.

Not to Rush-Laboratory Parameters and Procedural Complications in Patients Undergoing Left Atrial Appendage Closure

Background: As a preventive procedure, minimizing periprocedural risk is crucially important during left atrial appendage closure (LAAC). Methods: We included consecutive patients receiving LAAC at nine centres and assessed the relationship between baseline characteristics and the acute procedural outcome. Major procedural complications were defined as all complications requiring immediate invasive intervention or causing irreversible damage. Logistic regression was performed and included age and left-ventricular function. Furthermore, the association between acute complications and long-term outcomes was evaluated. Results: A total of 405 consecutive patients with a median age of 75 years (37% female) were included. 47% had a history of stroke. Median CHA2DS2-VASc score was 4 (interquartile range, 3−5) and the median HAS-BLED score was 3 (2−4). Major procedural complications occurred in 7% of cases. Low haemoglobin (OR 0.8, 95% CI 0.65−0.99 per g/dL, p = 0.040) and end-stage kidney disease (OR 13.0, CI 2.5−68.5, p = 0.002) remained significant in multivariate analysis. Anaemia (haemoglobin < 12 and < 13 g/dL in female and male patients) increased the risk of complications 2.2-fold. Conclusions: The major complication rate was low in this high-risk patient population undergoing LAAC. End-stage kidney disease and low baseline haemoglobin were independently associated with a higher major complication rate.

Combined atrial fibrillation ablation and left atrial appendage closure: Watchman vs. LAmbre devices

BACKGROUND

Left atrial appendage closure (LAAC) combined with radiofrequency catheter ablation is an emerging one-stop hybrid procedure for non-valvular atrial fibrillation (AF). This study was performed to compare the efficacy and safety of the Watchman device vs. the LAmbre device for this combined procedure.

METHODS

Two hundred and thirty two patients with AF who underwent the combined procedure were enrolled and divided into two subgroups depending on the device choice: the Watchman-combined group (n = 118) and the LAmbre-combined group (n = 114). The periprocedural and follow-up adverse events in both groups were documented.

RESULTS

The mean CHA2DS2-VASc score and HAS-BLED score in the Watchman-combined group and LAmbre-combined group were 3.7 ± 1.5 vs. 3.8 ± 1.5 and 2.5 ± 1.1 vs. 2.3 ± 1.1, respectively (all P > 0.05). Successful LAAC was achieved in all patients. The rate of major periprocedural complications and AF recurrence at 6 months post-procedure were similar between the Watchman-combined group and LAmbre-combined group (0.8 vs. 0.9%, P = 1.00; 22.0 vs. 15.8%, P = 0.23). During 2.6 ±0 .7 vs.1.6 ± 1.6 years follow-up, the rate of major clinical adverse events, including stroke and major bleeding, were comparable between the Watchman-combined group and the LAmbre-combined group (2.6 vs. 1.1% per 100 patient-years, P = 0.33). The intraprocedural peri-device leakage (PDL) rate was similar between the Watchman-combined group and the LAmbre-combined group (5.1 vs. 6.1%, P = 0.73), but the PDL rate was significantly higher at 3-6 months transesophageal echocardiography (TEE) follow-up than the intraprocedural PDL rate in both groups (21.6 vs. 5.1%; 36.6 vs. 6.1%, respectively), with a more obvious increase in minimal PDL rate in the LAmbre-combined group than the Watchman-combined group (36.6 vs. 21.6%, P < 0.05).

CONCLUSION

The Watchman and LAmbre devices were comparable in efficacy and safety for the combined procedure. The minimal PDL rate at short-term TEE follow-up was higher in the LAmbre-combined group than the Watchman-combined group.

Stroke Prevention in Atrial Fibrillation

PURPOSE OF REVIEW

Atrial fibrillation is associated with a significant increase in stroke and systemic embolism. This review explores the areas of stroke prevention.

RECENT FINDINGS

In the last decade, NOAC has overtaken warfarin as the anticoagulant of choice for stroke prevention in AF. For patients unable to take anticoagulation, LAA closure has proven to be a valid option. The use of digital devices has led to widespread consumer-directed AF screening. It remains to be determined if all device detect AF pose the same amount of risk as recent studies have shown that short and infrequent episodes of AF may not benefit from anticoagulation. Stroke prevention is paramount in the management of AF. In this review we describe the risk factors contributing to stroke, recent advances in antithrombotic therapies, and the increasing role of digital health in guiding AF detection and stroke prevention.

Percutaneous left atrial appendage occlusion discrepancy between randomised trials and clinical practice

In patients with atrial fibrillation and previous episodes of bleeding on oral anticoagulant treatment, left atrial appendage occlusion (LAAO) has emerged as an alternative way to decrease the risk of stroke.

The use of the procedure has been on the rise, and the news coverage has been dominated by an uncritical acceptance of the benefit of this procedure, which probably have contributed to the increasing number of procedures.

This commentary is a presentation and critical appraisal of the available evidence on the efficacy and safety of left atrial appendage closure as stroke prophylaxis.

We illustrate that LAAO is supported by limited randomised data risk of serious complications, which we do not believe supports the current widespread use.