Left atrial appendage closure for stroke prevention in non-valvular atrial fibrillation: rationale, devices in clinical development and insights into implantation techniques

Transseptal puncture in left atrial appendage closure guided by 3D printing and multiplanar CT reconstruction

BACKGROUND

The presented study investigates the application of bi-arterial 3D printed models to guide transseptal puncture (TSP) in left atrial appendage closure (LAAC).

AIMS

The objectives are to (1) test the feasibility of 3D printing (3DP) for TSP guidance, (2) analyse the distribution of the optimal TSP locations, and (3) define a CT-derived 2D parameter suitable for predicting the optimal TSP locations.

METHODS

Preprocedural planning included multiplanar CT reconstruction, 3D segmentation, and 3DP. TSP was preprocedurally simulated in vitro at six defined sites. Based on the position of the sheath, TSP sites were classified as optimal, suboptimal, or nonoptimal. The aim was to target the TSP in the recommended position during the procedure. Procedure progress was assessed post hoc by the operator.

RESULTS

Of 68 screened patients, 60 patients in five centers (mean age of 74.68 ± 7.64 years, 71.66% males) were prospectively analyzed (3DP failed in one case, and seven patients did not finally undergo the procedure). In 55 patients (91.66%), TSP was performed in the optimal location as recommended by the 3DP. The optimal locations for TSP were postero-inferior in 45.3%, mid-inferior in 45.3%, and antero-inferior in 37.7%, with a mean number of optimal segments of 1.34 ± 0.51 per patient. When the optimal TSP location was achieved, the procedure was considered difficult in only two (3.6%) patients (but in both due to complicated LAA anatomy). Comparing anterior versus posterior TSP in 2D CCT, two parameters differed significantly: (1) the angle supplementary to the LAA ostium and the interatrial septum angle (160.83° ± 9.42° vs. 146.49° ± 8.67°; p = 0.001), and (2) the angle between the LAA ostium and the mitral annulus (95.02° ± 3.73° vs. 107.38° ± 6.76°; p < 0.001), both in the sagittal plane.

CONCLUSIONS

In vitro TSP simulation accurately determined the optimal TSP locations for LAAC and facilitated the procedure. More than one-third of the optimal TSP sites were anterior.

Neurologic complications of atrial fibrillation: Pharmacologic and interventional approaches to stroke prevention

Atrial fibrillation is a common cardiac arrhythmia that carries a risk of stroke. This is commonly stratified with the CHA₂DS₂-VASc score. Stroke risk can be reduced with anticoagulants or with interventions to close the left atrial appendage, the most common source of left atrial thrombi. While warfarin has been traditionally used as the only oral anticoagulant available, there are several direct oral anticoagulants that compare favorably with respect to both stroke and bleeding risk in randomized controlled trials. Multiple interventional options exist to close the left atrial appendage, but the Watchman device is the only one that compares favorably with warfarin in randomized controlled trials.

Plugs for left atrial appendage occlusion: an overview of available devices

INTRODUCTION

Approximately one-third of all ischemic strokes and the ensuing health and economic burden can be attributed to the presence of atrial fibrillation (AF). The global prevalence of AF continues to rise, thus making it by far the most common diagnosed cardiac arrhythmia. Percutaneous left atrial appendage (LAA) occlusion or obliteration has been developed to protect from the occurrence of stroke in patients with nonvalvular AF.

AREAS COVERED

We address the characteristics and techniques for implantation as well as some clinical registries and randomized trials of the various catheter-based devices for the occlusion of the LAA that are either currently available or in the clinical evaluation stage.

EXPERT OPINION

Over less than 2 decades, LAA occlusion progressed from being a concept applied in a few specialized centers to a globally recognized procedure implemented in numerous hospitals as part of daily interventional practice. The respective devices are to date safer and easier to deploy than initially. Periprocedural and postprocedural complications will continue to decrease as already evident from prospective randomized trials and registries. Although current indications focus on patients with nonvalvular AF and contraindications for oral anticoagulation, it is all but certain that the future will bring a widening in the spectrum of indications, applicability, and usage of these devices.

Cerebral protection in left atrial appendage closure in the presence of appendage thrombosis

BACKGROUND

Presence of thrombus in the left atrial appendage (LAA) remains a severe contraindication to the percutaneous left atrial appendage closure procedure (LAAC), due to increased embolic risk. Recently, the experience developed in cerebral protection device in transcatheter aortic valve implantation (TAVI) procedure was translated in LAAC to address this issue.

AIM

To evaluate efficacy and safety of Sentinel cerebral protection system (CPS) in supporting LAAC in real-world patient with persistent LAA thrombus.

METHODS AND RESULTS

The study retrospectively enrolled consecutive patients with non-valvular atrial fibrillation (NVAF) and thrombus in LAA who underwent LAAC supported by Sentinel CPS in seven European high-volume centres. Twenty-seven patients were included with a median age of 69.1 ± 9.7 years old, with median CHA₂ DS₂ -VASc and HAS-BLEED scores 3 [2-5] and 3 [2.75-4], respectively. Technical and procedural success was achieved in all patients. No periprocedural TIA, stroke, or supra-aortic trunks dissection was recorded.

CONCLUSIONS

In this multicenter registry, LAAC supported by Sentinel CPS in patients with LAA persistent thrombus seems to be a safe and efficacious treatment.

[Left atrial appendage occlusion in patients with nonvalvular atrial fibrillation : Present evidence, ongoing studies, open questions]

About every fifth ischemic stroke is caused by atrial fibrillation. Oral anticoagulation is highly effective in secondary stroke prevention, but a relevant portion of patients with atrial fibrillation is not (permanently) anticoagulated for a variety of reasons. Based on present evidence, no general recommendation can be given for left atrial appendage occlusion in patients with nonvalvular atrial fibrillation. However, left atrial appendage occlusion is a treatment option after severe anticoagulation-related bleeding, if the cause of bleeding is not treatable. Left atrial appendage occlusion is critical in patients with a relative contraindication for oral anticoagulation or lack of adherence to given medication. It seems to be important that further randomized studies confirm a benefit of left atrial appendage occlusion in selected patients with nonvalvular atrial fibrillation. In addition, it is vital to clarify whether discontinuation of antiplatelets is feasible after catheter-based left atrial appendage occlusion, as antiplatelets are associated with a risk of bleeding. Within this review article, we discuss present evidence, gaps of knowledge and provide an overview on ongoing clinical studies. In addition, we summarize the design of the CLOSURE-AF study. This randomized multicenter study will start recruitment soon and is funded by the German Center for Cardiovascular Research e. V.

[Left atrial appendage closure in non-valvular atrial fibrillation]

Atrial fibrillation is the most frequent cardiac arrhythmia worldwide, causing approximately 20% of all ischemic strokes. Therefore, oral anticoagulation is recommended in patients with atrial fibrillation with at least a moderate risk of stroke; however, there is a significant proportion of patients who cannot undergo long-term oral anticoagulation. As the left atrial appendage is of major relevance for atrial fibrillation-induced thrombus formation, catheter-based or surgical closure of the left atrial appendage appears to be a promising therapeutic option. Large registry studies including patients with catheter-based left atrial appendage closure have proven its effectiveness and a decreasing procedure-related complication rate. This review article summarizes the current knowledge and introduces major ongoing randomized studies, which will investigate the impact of left atrial appendage closure on stroke prevention. The authors hope that the results of the randomized CLOSURE AF trial, which is funded by the German Center for Cardiovascular Research e. V. and is now recruiting patients in Germany, will help to solve many of the currently prevalent clinical questions.

Technical aspects of a successful transvascular retrieval of an acutely dislodged WaveCrest® left atrial appendage occluder

Percutaneous left atrial appendage (LAA) closure is an alternative therapy in patients with atrial fibrillation who are not suitable for anticoagulation. However, device embolization is one of the notable complications which inevitably requires catheter or surgical retrieval. In addition to previously reported Watchman® or AMULET® occluder embolization, here we report the first case of a WaveCrest® occluder dislodgement which was successfully removed by transcatheter technique. Instead of using the well-known snaring technique, we used a "wiring and ballooning technique" for retrieval. Considering its specific architecture without having hooks or feet where suitable for grasping, this technique is an option for retrieving WaveCrest® devices.

Role of real time-three dimensional transesophageal echocardiography in left atrial appendage closure with LACBES® devices

Catheter-based left atrial appendage closure (LAAC) has recently become an innovative strategy for preventing embolic events in patients with nonvalvular atrial fibrillation (AF). There is limited information on optimal sizing for LAAC with the recently developed LACBES^® device. The aim of the present study was to assess the role of real time-three dimensional transesophageal echocardiography (RT-3D TEE) for LACBES^® device selection during LAAC. A total of 22 patients with nonvalvular AF and indications for LAAC were enrolled in the study. All patients underwent LAAC with LACBES^® devices. TEE was performed in all patients 3 days prior to the procedure, during the procedure, and 3 months and 1 year following the procedure. Interatrial septal puncture, exchange of the sheath and release of the device were performed under the guidance of RT-3D TEE. The LAA ostium and landing zone dimensions measured by RT-3D TEE were better correlated with the device size used for occlusion (r=0.60, P=0.003) than those measured with two dimensional TEE or LAA contrast angiography. There were no clinically significant residual shunts, pericardial effusion or tamponade following occlusion. All patients had the device well-seated and presented no evidence of closure-associated complications during the follow-up. No cases of peri-procedural stroke or mortality were observed during a mean follow-up period of 12 months. In conclusion, RT-3D TEE is a reliable and effective imaging modality to guide LAAC using LACBES^® devices in patients with nonvalvular AF at high risk of cardioembolic events.

Left atrial appendage angiography is associated with the incidence and number of magnetic resonance imaging-detected brain lesions after percutaneous catheter-based left atrial appendage closure

BACKGROUND

Percutaneous catheter-based left atrial appendage closure (LAAC) is a procedure being increasingly performed in patients with atrial fibrillation and high bleeding risk.

OBJECTIVE

The purpose of this study was to evaluate the incidence of magnetic resonance imaging (MRI)-detected acute brain lesions (ABLs) as well as potential changes in neurocognitive function after percutaneous LAAC in patients with atrial fibrillation.

METHODS

Brain MRI at 3 T was performed within 24 hours before and after LAAC along with neurologic (National Institutes of Health Stroke Scale [NIHSS] score) and cognitive (Montreal Cognitive Assessment [MoCA] test) assessment. Acquired MRI sequences included high-resolution diffusion-weighted imaging as well as fluid-attenuated inversion recovery.

RESULTS

Successful device implantation was achieved in all 23 patients (age 74.1 ± 10.5 years; 16 male) using the Amulet (n = 18), Occlutech (n = 3), or LAmbre (n = 2) device. Thirty-seven ABLs were detected by MRI in 12 of 23 patients (52%) after LAAC. The number of periprocedural LAA angiographies was significantly higher in patients with ABL than in those without ABL (1.67 ± 0.65 vs 1.18 ± 0.41; P = .048) and was associated with a higher number of ABL (ρ = 0.615; P = .033). Compared to pre-LAAC assessment, post-LAAC MoCA and NIHSS scores revealed similar results. After LAAC, MoCA test (mean 24.1 ± 4.6 vs 23.2 ± 4.6; P = .09) and NIHSS score (mean 1.0 ± 1.7 vs 1.2 ± 1.8; P = .1) were similar between patients with and those without ABL, respectively.

CONCLUSION

MRI-detected ABLs are commonly observed after percutaneous LAAC. The number of LAA angiographies is significantly associated with the number of ABLs; however, the clinical implications of ABL have yet to be determined.

Percutaneous Left Atrial Appendage Occlusion for the Prevention of Stroke in Patients with Atrial Fibrillation: Review and Critical Appraisal

The authors review the current status of percutaneous left atrial appendage (LAA) occlusion therapy in patients with atrial fibrillation with the goal to prevent ischemic stroke and systemic embolism and to reduce oral anticoagulation associated bleeding. While we cover the historical and also surgical background, and all tested devices, the main focus rests on the single currently U.S. Food and Drug Administration (FDA) approved LAA occluder, the WATCHMAN device, and its approval process. The authors also give a critical appraisal beyond the review of mere facts, trying to put the current data into perspective.

Safety and efficacy of early anticoagulation drug regimens after WATCHMAN left atrial appendage closure: three-month data from the EWOLUTION prospective, multicentre, monitored international WATCHMAN LAA closure registry

AIMS

While LAA closure has recently been incorporated into both European and US guidelines for stroke prevention, uncertainties regarding post-procedural drug therapy so far limit its adoption. The aim of this analysis is to compare real-world outcome data stratified for the post-procedural drug regimen employed.

METHODS AND RESULTS

One thousand and five patients were implanted with a WATCHMAN device in the prospective EWOLUTION study at 47 centres; 73.5% of the patients were deemed contraindicated for long-term OAC therapy. Here we report on three-month data including the first follow-up TOE exam for 94% of the study population. Following LAA closure, patients received DAPT, VKA, NOAC, single antiplatelet or no therapy (60.3%, 15.4%, 10.9%, 7% and 6.5%, respectively). Device thrombus (2.6%), stroke (0.4%) and major bleeding SAE (2.6%) rates were low overall and did not vary by post-implantation medication strategy. Patients on NOAC had the lowest bleeding rate, without an increase in device thrombus or stroke rates.

CONCLUSIONS

LAA closure with the WATCHMAN device is feasible in patients with a relative or absolute contraindication to oral anticoagulation. Neither DAPT nor NOAC therapy leads to a significant increase in device thrombus, stroke or bleeding compared to the standard VKA regimen. Numerically, NOAC therapy had the lowest event rate.

First results of the Brazilian Registry of Percutaneous Left Atrial Appendage Closure

Background

Left atrial appendage closure (LAAC) is an effective alternative to oral anticoagulation (OA) for the prevention of stroke in patients with non-valvular atrial fibrillation (NVAF).

Objective

To present the immediate results and late outcomes of patients submitted to LAAC and included in the Brazilian Registry of Percutaneous Left Atrial Appendage Closure.

Methods

91 patients with NVAF, high stroke risk (CHA₂DS₂VASc score = 4.5 ± 1.5) and restrictions to OAC (HAS-BLED score = 3.6 ± 1.0) underwent 92 LAAC procedures using either the Amplatzer cardiac plug or the Watchman device in 11 centers in Brazil, between late 2010 and mid 2016.

Results

Ninety-six devices were used (1.04 device/procedure, including an additional non-dedicated device), with a procedural success rate of 97.8%. Associated procedures were performed in 8.7% of the patients. Complete LAAC was obtained in 93.3% of the successful cases. In cases of incomplete closure, no residual leak was larger than 2.5 mm. One patient needed simultaneous implantation of 2 devices. There were 7 periprocedural major (5 pericardial effusions requiring pericardiocentesis, 1 non-dedicated device embolization and 1 coronary air embolism without sequelae) and 4 minor complications. After 128.6 patient-years of follow-up there were 3 deaths unrelated to the procedure, 2 major bleedings (one of them in a patient with an unsuccessful LAAC), thrombus formation over the device in 2 cases (both resolved after resuming OAC for 3 months) and 2 strokes (2.2%).

Conclusions

In this multicenter, real world registry, that included patients with NVAF and high thromboembolic and bleeding risks, LAAC effectively prevented stroke and bleeding when compared to the expected rates based on CHA₂DS₂VASc and HASBLED scores for this population. Complications rate of the procedure was acceptable considering the beginning of the learning curve of most of the involved operators.

Percutaneous Closure of Left Atrial Appendage affects Mid-Term Release of MR-proANP

The left atrial appendage (LAA) represents both a predisposing source of thrombus formation and of neuro-humoral haemostasis. This study aims to evaluate changes of biomarker expression before and after successful percutaneous closure of the LAA. Patients with atrial fibrillation and contraindication for oral anticoagulant therapy were enrolled. Blood samples were taken within 24 hours before (T1) and at least 6 months (mid-term) (T2) after successful implantation of LAA occlusion devices. Blood levels of high sensitivity troponin I and T (hsTnI, hsTnT), aminoterminal pro-brain natriuretic peptide (NT-proBNP) and mid-regional pro-atrial natriuretic peptide (MR-proANP) were evaluated at both time points. A total of 42 patients with successful percutaneous LAA closure were included. Median mid-term follow-up was of 183 days. HsTnT, hsTnI and NT-proBNP did not show any significant differences over time. Serum levels of MR-proANP increased significantly between immediate pre-intervention (T1: median = 245.7 pmol/l, IQR 155.8–361.3 pmol/l) and at mid-term follow-up (T2: median = 254 pmol/l, IQR 183.4–396.4 pmol/l) (p = 0.037). These results indicate, that percutaneous LAA closure affects neuro-humoral haemostasis by increasing MR-proANP serum levels at mid-term follow-up.

LAA occluder device for stroke prevention: Data on WATCHMAN and other LAA occluders

NOAC therapy has become the standard for stroke prevention in patients with atrial fibrillation. Yet some patients suffer extracranial bleeding events or have other reasons to seek non-pharmacologic stroke protection. LAA occlusion with the WATCHMAN device has been proven safe and effective for such patients and is now recommended in current guidelines for this patient group; other devices also seek approval.

Rationale of cerebral protection devices in left atrial appendage occlusion

AIMS

Aims of this case-series were to assess the feasibility of cerebral protection devices in interventional left atrial appendage occlusion (iLAAO) procedures and to yield insight into the pathomorphological correlate of early, procedural cerebral embolization during iLAAO.

METHODS AND RESULTS

Five consecutive patients underwent iLLO flanked by the Sentinel CPS® (Claret Medical, Inc., Santa Rosa, CA) cerebral protection system. Placement and recapture of the Sentinel^® device as well as the iLAAO were successful and safe in all cases. Histomorphometric analysis of the collected filters showed embolized debris in all patients. Acute thrombus was found in three patients, organizing thrombus in four. Interestingly, two patients had endocardial or myocardial tissue in their filters.

CONCLUSIONS

Cerebral protection during iLAAO with the Sentinel CPS^® device is feasible. Furthermore, this dataset identifies the formation and embolization of thrombus and cardiac tissue as emboligeneic sources and potential future targets to reduce procedural complications. © 2016 Wiley Periodicals, Inc.

Left Atrial Appendage and Closure

Patients with nonvalvular atrial fibrillation have a 4- to 5-fold increase in strokes and that rhythm may be responsible for 15% to 20% of all strokes, particularly in the elderly. In this setting, thrombus in the left atrial appendage has been found to be the source of stroke in 90% of cases. Although oral anticoagulants have been found effective in reducing stroke rates, for a variety of issues, they may only be used in 40% to 50% of patients at increased risk for stroke. Given pathophysiology of stroke, site-specific therapy directed at left atrial appendage occlusion has been now studied for stroke prevention, and one device is FDA approved (Watchman). A meta-analysis of 2 randomized clinical trials and 2 registries with this device documented the following: (1) patients receiving the device had significantly fewer hemorrhagic strokes (hazard ratio 0.22, P =0.004); (2) a significant reduction in cardiovascular or unexplained death (hazard ratio 0.48, P =0.004); (3) more ischemic strokes in the device group; however, when periprocedural events were excluded, the difference was not significant; and (4) a significant reduction in nonprocedural bleeding with the device (hazard ratio 0.51, P =0.006) versus control. At present, the only device approved in the United States is indicated in patients with nonvalvular atrial fibrillation with acceptable anatomy who are at increased risk for stroke and would be candidates for anticoagulation in whom there is concern about the risk/benefit ratio for chronic anticoagulation. Unresolved issues include optimal patient selection criteria, the role of devices in patients in whom anticoagulation is contraindicated, and the relative role of novel oral anticoagulants versus the device which has not been tested in randomized trials.

--LAA Occluder View for post-implantation Evaluation (LOVE)--standardized imaging proposal evaluating implanted left atrial appendage occlusion devices by cardiac computed tomography

Background

A standardized imaging proposal evaluating implanted left atrial appendage (LAA) occlusion devices by cardiac computed tomography angiography (cCTA) has never been investigated.

Methods

cCTA datasets were acquired on a 3^rd generation dual-source CT system and reconstructed with a slice thickness of 0.5 mm. An interdisciplinary evaluation was performed by two interventional cardiologists and one radiologist on a 3D multi-planar workstation. A standardized multi-planar reconstruction algorithm was developed in order to assess relevant clinical aspects of implanted LAA occlusion devices being outlined within a pictorial essay.

Results

The following clinical aspects of implanted LAA occlusion devices were evaluated within the most appropriate cCTA multi-planar reconstruction: (1) topography to neighboring structures, (2) peri-device leaks, (3) coverage of LAA lobes, (4) indirect signs of neo-endothelialization. These are illustrated within concise CT imaging examples emphasizing the potential value of the proposed cCTA imaging algorithm: Starting from anatomical cCTA planes and stepwise angulation planes perpendicular to the base of the LAA devices generates an optimal LAA Occluder View for post-implantation Evaluation (LOVE). Aligned true axial, sagittal and coronal LOVE planes offer a standardized and detailed evaluation of LAA occlusion devices after percutaneous implantation.

Conclusions

This pictorial essay presents a standardized imaging proposal by cCTA using multi-planar reconstructions that enables systematical follow-up and comparison of patients after LAA occlusion device implantation.

Electronic supplementary material

The online version of this article (doi:10.1186/s12880-016-0127-y) contains supplementary material, which is available to authorized users.

Safety and Efficacy of Left Atrial Appendage Closure with the Amplatzer Cardiac Plug in Very High Stroke and Bleeding Risk Patients with Non-Valvular Atrial Fibrillation

Introduction

Limited data exist on the outcomes after left atrial appendage closure (LAAC) with the Amplatzer™ Cardiac Plug (ACP; St. Jude Medical, Minneapolis, MN, USA) in patients with atrial fibrillation (AF) with very high stroke and bleeding risks, the subset expected to benefit most from this procedure. The objective of this study was to report clinical outcomes after LAAC with the ACP device in a very high stroke and bleeding risk cohort of patients with non-valvular AF and contraindications to oral anticoagulation (OAC).

Methods

LAAC using the ACP device was performed in 96 patients with AF who had median CHA₂DS₂-VASc and HAS-BLED scores of 5 and 3, respectively. Post-procedure, patients received dual antiplatelet therapy for 6 months. A transesophageal echocardiography (TEE) was scheduled at 6 months.

Results

Procedural success was 100%. Procedural-related complications occurred in 7.3% (pericardial effusion, 4.2%; thromboembolic events, 2.1%; device embolization, 1.0%). Additional thromboembolic events occurred in three patients during follow-up (92.7% follow-up). After 93.4 patient-years of follow-up, the annual rates of thromboembolic and major bleeding events were 3.2% and 1.1%, respectively. In those with TEE follow-up (70%), complete LAAC with no leaks was observed. Thrombus formation on the device was noted on TEE in two patients.

Conclusion

LAAC using the ACP device was associated with an acceptable low rate of embolic and bleeding events after a median follow-up of 9 months in a cohort of patients with AF who were amongst the highest stroke and bleeding risks reported so far in LAAC trials.

Electronic supplementary material

The online version of this article (doi:10.1007/s40119-015-0053-z) contains supplementary material, which is available to authorized users.

Initial Experience With Novel Oral Anticoagulants During the First 45 Days After Left Atrial Appendage Closure With the Watchman Device

BACKGROUND

The use of oral anticoagulation or dual antiplatelet therapy (DAPT) is recommended within the first 45 days after left atrial appendage (LAA) closure using the Watchman device because of incomplete device endothelialization. This study reports for the first time the feasibility of novel oral anticoagulants (NOAC) in these patients.

HYPOTHESIS

NOAC therapy is safe and effective after LAA closure.

METHODS

Interventional LAA closure was performed successfully in 45 patients. Of these, 18 patients received NOAC during the first 45 days after implantation and 27 patients received DAPT. Transesophageal echocardiography was conducted 45 days after implantation. The primary study endpoint was abnormal thrombus apposition 45 days after implantation. Secondary study endpoints were death from any cause, major adverse cardiac and cerebrovascular events (MACCE), and major bleedings.

RESULTS

After 45 days, transesophageal echocardiography revealed no abnormal thrombus apposition. During a follow-up of 417 ± 323 days, 7 patients died. No stroke or transient ischemic attack occurred. Nonfatal myocardial infarction occurred in 1 patient. There was a nonsignificant trend for lower all-cause mortality (P = 0.159) and occurrence of MACCE (P = 0.096) in the NOAC group compared with the DAPT group. Overall, 6 patients suffered from a major bleeding (NOAC, n = 3; DAPT, n = 3). In NOAC group, major bleedings (at day 205, 688, and 736) occurred long after termination of NOAC therapy. There was no significant difference in the frequency of major bleedings in different groups.

CONCLUSIONS

Our pilot study suggests that NOAC therapy within the first 45 days after interventional LAA closure is safe and effective.

Real World Outcomes of Left Atrial Appendage Occlusion

Percutaneous left atrial appendage occlusion (LAAO) is a device-based therapy for the prevention of stroke in patients with non-valvular atrial fibrillation (AF). Recently, the Watchman device (Boston Scientific, St Paul, MN, US) was approved in the US by the Food and Drug Administration (FDA) based on the results of two randomised clinical trials that evaluated LAAO in patients eligible for oral anticoagulation (OAC) therapy. However, in real-word clinical practice LAAO is typically offered to patients ineligible for OAC therapy, as they appear to have limited treatment options and consequently worse prognosis. Although LAAO has shown favourable clinical outcomes in OAC-ineligible patients in single or multicentre observational studies, these results need to be confirmed in randomised clinical trials.

Cardiac Plug I and Amulet Devices: Left Atrial Appendage Closure for Stroke Prophylaxis in Atrial Fibrillation

Percutaneous left atrial appendage (LAA) occlusion has emerged as an exciting and effective modality for stroke prophylaxis in patients with non-valvular atrial fibrillation who are deemed too high risk for anticoagulation with warfarin or newer anticoagulants. The Amplatzer devices have been used in LAA occlusion for more than a decade, starting with off label use of an atrial septal occluder device for LAA occlusion. This was followed by introduction of a dedicated Amplatzer cardiac plug (ACP) 1 for LAA occlusion, and more recently, the second generation Amulet device, with reported better stability enhancing features, has been introduced. Both these devices are widely used outside the United States, however in the US only the WATCHMAN device has been FDA approved. Unlike the WATCHMAN device, where the evidence is continuously building as the data from two pivotal randomized controlled trials are emerging, most of the evidence for ACP devices is from pooled multicenter registry data. In this article, we review the device design, implantation techniques and the most recently published evidence for both the Amplatzer cardiac plug 1 and the newer Amulet device. Our goal is to summarize the most recent literature and discuss the current role of the Amplatzer devices in the exciting and rapidly growing field of percutaneous LAA occlusion.

The WATCHMAN device for stroke prophylaxis in atrial fibrillation: an evolving niche

Atrial fibrillation is associated with a markedly increased risk of thromboembolic stroke. At present, lifelong antithrombotic therapy with warfarin or a novel oral anticoagulant is indicated for prophylaxis in the majority of patients. Left atrial appendage occlusion devices have been developed as an alternative to these agents, aiming to avoid issues around consistency of anticoagulation, bleeding risk, and drug-related side effects. The best evidence is available for Boston Scientific's WATCHMAN device. The safety and efficacy of WATCHMAN and other similar devices have been questioned, although the increasing body of evidence supports a role in selected settings. A recently updated randomized controlled trial of WATCHMAN (WATCHMAN Left Atrial Appendage System for Embolic PROTECTion in Patients with Atrial Fibrillation [PROTECT-AF]) demonstrates its noninferiority to warfarin and suggests an advantage in terms of functional outcome for patients, with superior net clinical benefit 6 to 9 months after starting treatment. The procedural risk associated with device implantation remains substantial, although improving device design and increasing operator experience means that this should decrease in the future. As the body of data and overall experience around WATCHMAN grow, it may come to be recognized as the best option in selected patients.