An update and current expert opinions on percutaneous left atrial appendage occlusion for stroke prevention in atrial fibrillation

[Fermeture de l'oreillette gauche - une alternative à l'anticoagulation permanente en cas de fibrillation auriculaire?]

Left Atrial Appendage Closure- An Alternative to Continuous Anticoagulation for Atrial Fibrillation? Abstract. Approximately 25% of all ischemic insults are caused by cardiac emboli in atrial fibrillation. Therefore, in patients with atrial fibrillation, oral anticoagulation is initiated or transesophageal echocardiography is performed before electroconversion to exclude blood clots in the heart. This shows that virtually all cardiac thrombi (>90%) are localized in the atrial ear. Therefore, for many decades surgeons have been removing the atrial tube during open heart surgery to eliminate it as a source of emboli. As a minimally invasive alternative, various screens for percutaneous closure of the atrial ear have been developed in the past 10-20 years. The requirements, techniques, and results will be discussed in the following article.

Left atrial appendage occlusion in recurrent ischaemic stroke, a multicentre experience

BACKGROUND

Oral anticoagulation therapy (OAC) remains the gold standard for ischaemic stroke prevention in patients with non-valvular atrial fibrillation (NVAF) and elevated stroke risk. Percutaneous left atrial appendage occlusion (LAAO) has emerged as a potential alternative for stroke prevention in patients who cannot tolerate OAC. Although no randomized data is available, recurrent stroke in NVAF-patients, while on adequate OAC, is regarded as a treatment failure and therefore is considered as a potential indication for LAAO, based upon expert opinion.

METHODS/OBJECTIVES

A multicentre retrospective cohort study evaluating efficacy, safety and mortality of LAAO in NVAF-patients presenting with recurrent ischaemic stroke, after excluding other plausible causes.

RESULTS

Fifteen LAAO have been performed in NVAF-patients with recurrent stroke despite ongoing OAC, after exclusion of other plausible causes. Mean age was 78.1 ± 5.8 years, mean CHA2DS2-VASc-score = 6 ± 1.2 and mean HAS-BLED-score = 5 ± 1.2. Successful implantation was achieved in all patients (73% Amplatzer device and 27% Watchman device), without any access-related complications and only one procedure/device-related complication (device embolization) was reported. In all but four patients, OAC was continued at long term after LAAO. No haemorrhagic strokes and only two ischaemic strokes were observed. During follow-up three patients died, all due to non-atrial fibrillation or non-device-related causes.

CONCLUSIONS

In NVAF-patients at high risk for stroke presenting with recurrent stroke despite adequate OAC, LAAO may be considered an adjunctive, but not alternative treatment to OAC with high feasibility and safety.

Abbreviations: AF: atrial fibrillation; ESC: European Society of Cardiology; INR: international normalized ratio; LAA: left atrial appendage; LAAO: left atrial appendage occlusion; NOAC: non-vitamin K oral anticoagulants; NVAF: non-valvular atrial fibrillation; OAC: oral anticoagulation; RS: recurrent (ischaemic) stroke; SD: standard deviation; TIA: transient ischaemic attack; TOE: transoesophageal echocardiography; TTE: transthoracic echocardiography; VKA: vitamin K antagonists.

Modification of Serum Natriuretic Peptide Profile and Echocardiographic Parameters After Surgical Left Atrial Appendage Exclusion/Resection During Mitral Valve Surgery

BACKGROUND

Being a well-recognised source of cardiac embolism, the left atrial (LA) appendage (LAA) is frequently excluded during mitral valve (MV) surgery. However, the LAA is also a source of cardiac hormones and a new drug (sacubitril), which beneficially interferes with hormonal imbalance during heart failure, leads to re-evaluation of the LAA for the maintenance of adequate hormone production in the heart. We compared the effects of LAA surgical resection/exclusion in patients with MV replacement (MVR) on natriuretic peptides (NPs) and related enzymes versus similar patients, in whom the LAA was preserved. A comparison of clinical response was also carried out.

METHOD

Haemodynamically stable patients scheduled for MV surgery with or without elimination of the LAA were studied before and 3 months after surgery. Serum NPs, furin, corin, and neprilysin were determined. A transthoracic echocardiogram was also performed before and after surgery.

RESULTS

Patients in the LAA intervention group exhibited lower levels of atrial natriuretic peptide (ANP) 3 months after surgery than patients with intact LAAs. There were no differences in NP and related enzyme levels pre- or postsurgery. The echocardiograms indicated a similar decrease in the diameters and volumes of the LA, and normal pulmonary arterial pressure values, in both groups. The indexed LA volume showed a positive correlation with postoperative brain natriuretic peptide.

CONCLUSIONS

Surgical resection or exclusion of the LAA in patients with MVR promotes a decrease in ANP production at 3 months postsurgery. Echocardiography is useful when evaluating surgical replacement of the MV with elimination of the LAA.

Device-Related Thrombus After Left Atrial Appendage Occlusion With the Amulet Device

BACKGROUND

Left atrial appendage occlusion (LAAO) is increasingly used for stroke prevention in patients with atrial fibrillation who are considered unsuitable for a lifelong oral anticoagulant regimen. Recently, a single-centre study reported device-related thrombus formation in 16.7% of patients treated with the second-generation Amulet device (St. Jude Medical, St. Paul, MN, USA), presenting a potential major safety concern. As "real-world" data on device-related thrombus formation following LAAO with the Amulet occluder are scarce, we aimed to evaluate this outcome in a retrospective registry.

METHODS

Clinical and tranosesophageal echocardiography data after LAAO with the Amulet in consecutive patients from three centres were collated.

RESULTS

Among 38 patients (mean age 75.8 years), mean (standard deviation) CHA₂DS₂-VASc and HAS-BLED scores were 4.4 (1.2) and 3.4 (0.9), respectively. All patients underwent successful device placement without procedure-related adverse events. The antithrombotic regimen at discharge consisted of dual antiplatelet therapy (DAPT) in 27 patients (71.1%), single antiplatelet therapy in 10 patients (26.3%), and no antithrombotic therapy in one patient (2.6%). Device-related thrombus was observed in one patient (2.6%) despite DAPT regimen. The outcome of this patient was uncomplicated after adjustment of oral anticoagulant therapy. No patients presented with a thromboembolic event following LAAO during a mean (standard deviation) follow-up of 15 (5) months.

CONCLUSIONS

In this retrospective study, device-related thrombus formation with the second-generation Amulet device was rare and occurred at a rate similar to that of the previous device. Importantly, no patient experienced a device-related thromboembolic event during follow-up. Larger real-life studies are required to confirm the safety profile of this increasingly used device.

Percutaneous left atrial appendage occlusion: the Munich consensus document on definitions, endpoints, and data collection requirements for clinical studies

The increasing interest in left atrial appendage occlusion (LAAO) for ischaemic stroke prevention in atrial fibrillation (AF) fuels the need for more clinical data on the safety and effectiveness of this therapy. Besides an assessment of the effectiveness of the therapy in specific patients groups, comparisons with pharmacological stroke prophylaxis, surgical approaches, and other device-based therapies are warranted. This paper documents the consensus reached among clinical experts in relevant disciplines from Europe and North America, European cardiology professional societies, and representatives from the medical device industry regarding definitions for parameters and endpoints to be assessed in clinical studies. Adherence to these definitions is proposed in order to achieve a consistent approach across clinical studies on LAAO among the involved stakeholders and various clinical disciplines and thereby facilitate continued evaluation of therapeutic strategies available.

Initial experience with the WATCHMAN™ left atrial appendage system for stroke prevention in atrial fibrillation: A single-centre registry

BACKGROUND

Left atrial appendage (LAA) closure using the WATCHMAN™ device (WM) may be considered in patients with non-valvular atrial fibrillation (AF) and a high-risk of stroke who are ineligible for long-term oral anticoagulation (OAC).

AIM

To report our single-centre preliminary experience, focusing on feasibility, safety and short-term efficacy of this procedure.

METHODS

Patients implanted from December 2013 to February 2014 were included. The procedure, performed under general anaesthesia, was guided by fluoroscopy and transoesophageal echocardiography (TOE). Efficacy was defined as the ability to implant the WM with no peridevice leak; safety was defined as the occurrence of in-hospital and 45-day events, including stroke, pericardial effusion and device migration.

RESULTS

Twenty-three patients (mean age: 77.6 years; 16 men [69.6%]; mean CHA₂DS₂-VASc score: 5) underwent WM implantation. The indication was gastrointestinal bleeding in 14 (60.9%) patients, cerebral haemorrhage in eight (34.8%) and need for long-term ticagrelor after stent thrombosis on clopidgrel in one (4.3%). Procedural success was 95.7% (95% confidence interval: 77.3-100.0); efficacy was 90.9% (95% confidence interval: 71.0-98.7). The size of the implanted WATCHMAN™ device was in agreement with the prespecified size, based on measurement of the LAA, in 56.5% of cases. In five cases, the criteria were not met, but the device was successfully implanted in four of these, with a good result (80.0%). Treatment at discharge was a reduced dose of anticoagulant plus aspirin in three cases (13.0%) or antiplatelet therapy alone in 20 cases (90.9%). No adverse event occurred during the index hospitalization or at 45 days. At 45 days, the LAA was sealed in 18/19 patients (94.7%) on TOE, with no difference between those who did or did not have an implanted device of the prespecified size.

CONCLUSION

When performed by an operator trained in the procedure, WM implantation appears to be safe and effective. This procedure may be considered in patients at high-risk of stroke who are ineligible for long-term OAC.

The evolving landscape of oral anti-arrhythmic prescriptions for atrial fibrillation in England: 1998-2014

AIMS

An important decision in the management of patients with atrial fibrillation is whether to adopt a rate or rhythm control strategy. Options for the latter include oral membrane-active anti-arrhythmic drugs (AADs) or catheter ablation. Recent prescription trends may have been affected by the introduction of dronedarone and an increasing number of reports suggesting increased mortality in those taking AADs. We describe the trend in oral AAD prescriptions in England in the period 1998-2014.

METHODS AND RESULTS

We conducted a retrospective study using data from the Prescription Cost Analysis system, which holds information on every prescription dispensed in the community in England. We obtained data from 1998 to October 2014 for all Class Ia, Ic, and III AADs. Amiodarone and sotalol remain the most commonly prescribed AADs in England, though the use of both is decreasing. There has been a linear increase in the uptake of flecainide. Dronedarone prescriptions peaked in 2011, and our most recent data show that amiodarone prescriptions are 25-fold those of dronedarone.

CONCLUSION

There is a decline in the use of amiodarone and sotalol consistent with the growing safety concerns with these drugs along with neutral results from landmark trials comparing rate and rhythm control. Dronedarone has failed to make an impact on AAD prescribing. In contrast, flecainide has seen an increase in use during the study period.

Stroke prevention following modified endoscopic ablation and appendectomy for atrial fibrillation

We reported the results of stroke prevention following modified endoscopic procedure for atrial fibrillation. 82 patients underwent modified endoscopic procedure for atrial fibrillation (AF), in whom 47 had paroxysmal, 28 had persistent, and 7 had long-standing atrial fibrillation. CHA2DS2VASC median score was 3 (range from 0 to 8). The procedure was performed on the beating heart, through 3 ports on the left chest wall. Pulmonary vein isolation and ablation of the left atrium were achieved by bipolar radiofrequency ablation. Left atrial appendage (LAA) was excluded by stapler. Brain CT, cardiac CT and 24-h Holter monitoring were performed following the procedure. The procedure was successfully completed for all patients. The mean duration was 122 ± 40.1 min. LAA was excluded after appendectomy and checked by intraoperative transesophageal echocardiography. The mean follow-up duration was 24.3 ± 3.5 months. No patients showed signs and symptoms of transient ischemic attack or stroke. No new positive findings were demonstrated by recurring brain CT scan performed after the procedure. Cardiac CT confirmed the absence of LAA and thrombosis in the left atrium. 87.8 % (72/82) of all patients were in sinus rhythm. Our results demonstrate that the modified endoscopic procedure is a safe, effective, and appropriate treatment for AF, which restores sinus rhythm and may be associated with the prevention of AF-related stroke.

Left Atrial Appendage: Physiology, Pathology, and Role as a Therapeutic Target

Atrial fibrillation (AF) is the most common clinically relevant cardiac arrhythmia. AF poses patients at increased risk of thromboembolism, in particular ischemic stroke. The CHADS2 and CHA2DS2-VASc scores are useful in the assessment of thromboembolic risk in nonvalvular AF and are utilized in decision-making about treatment with oral anticoagulation (OAC). However, OAC is underutilized due to poor patient compliance and contraindications, especially major bleedings. The Virchow triad synthesizes the pathogenesis of thrombogenesis in AF: endocardial dysfunction, abnormal blood stasis, and altered hemostasis. This is especially prominent in the left atrial appendage (LAA), where the low flow reaches its minimum. The LAA is the remnant of the embryonic left atrium, with a complex and variable morphology predisposing to stasis, especially during AF. In patients with nonvalvular AF, 90% of thrombi are located in the LAA. So, left atrial appendage occlusion could be an interesting and effective procedure in thromboembolism prevention in AF. After exclusion of LAA as an embolic source, the remaining risk of thromboembolism does not longer justify the use of oral anticoagulants. Various surgical and catheter-based methods have been developed to exclude the LAA. This paper reviews the physiological and pathophysiological role of the LAA and catheter-based methods of LAA exclusion.

Total endoscopic ablation of atrial fibrillation

Total endoscopic ablation of atrial fibrillation is a treatment option in symptomatic patients after unsuccessful catheter ablation or when catheter ablation is considered inappropriate. We describe a technique of endoscopic ablation of the left atrium using temperature-controlled unipolar or bipolar radiofrequency. A left atrial box lesion encircling the pulmonary veins is created using three ports in the right hemithorax. The technical aspects and preliminary results of the procedure are discussed.

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.

Percutaneous left atrial appendage occlusion for stroke prevention in atrial fibrillation: an update

Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia encountered in clinical practice. One of its most devastating complications is the development of thromboembolism leading to fatal or disabling stroke. Oral anticoagulation (OAC, warfarin) is the standard treatment for stroke prevention in patients with AF with an increased stroke risk. However, there are several obstacles to long-term OAC therapy, including the risk of serious bleeding, several drug–drug interactions and the need for frequent blood testing. Although newer oral anticoagulants have been developed, these drugs also face issues of major bleeding and non-compliance. Therefore, alternative treatment options for stroke prevention in patients with AF with a high stroke risk are needed. Percutaneous left atrial appendage (LAA) occlusion is an evolving therapy, which should be taken into consideration in those patients with non-valvular AF with a high stroke risk and contraindications for OAC. This article aims to discuss the rationale for LAA closure, the available LAA occlusion devices and their clinical evidence until now. Moreover, we discuss the importance of proper patient selection, the role of various imaging techniques and the need for a more tailored postprocedural antithrombotic therapy.

Atrial fibrillation in heart failure: The sword of Damocles revisited

Heart failure (HF) and atrial fibrillation (AF) frequently coexist and have emerged as major cardiovascular epidemics. There is growing evidence that AF is an independent prognostic marker in HF and affects patients with both reduced as well as preserved LV systolic function. There has been a general move in clinical practice from a rhythm control to a rate control strategy in HF patients with AF, although recent data suggests that rhythm control strategies may provide better outcomes in selected subgroups of HF patients. Furthermore, various therapeutic modalities including pace and ablate strategies with cardiac resynchronisation or radiofrequency ablation have become increasingly adopted, although their role in the management of AF in patients with HF remains uncertain. This article presents an overview of the multidimensional impact of AF in patients with HF. Relevant literature is highlighted and the effect of various therapeutic modalities on prognosis is discussed. Finally, while novel anticoagulants usher in a new era in thromboprophylaxis, research continues in a variety of new pathways including selective atrial anti-arrhythmic agents and genomic polymorphisms in AF with HF.