Left atrial appendage occlusion for stroke prevention in atrial fibrillation: multicentre experience with the AMPLATZER Cardiac Plug

Five years of keeping a watch on the left atrial appendage-how has the WATCHMAN fared?

Left atrial appendage closure (LAAC) is a promising site-directed therapy for stroke prevention in patients with non-valvular atrial fibrillation (AF) who are ineligible or contraindicated for long-term oral anticoagulation. A variety of LAAC modalities are available, including percutaneous endocardial occluder devices such as WATCHMAN^TM (Boston Scientific Corp., Marlborough, MA, USA), and an ever-increasing body of evidence is helping to define the optimal use of each technique. Similarly increased experience with LAAC has revealed challenges such as device-related thrombi and peri-device leaks for which the long-term significance and appropriate management are areas of active investigation. We review the evolution and long-term outcomes with the WATCHMAN^TM device with particular emphasis on the nuances of its use and its role in the broader landscape of appendageology.

Device-associated thrombus formation after left atrial appendage occlusion: A systematic review of events reported with the Watchman, the Amplatzer Cardiac Plug and the Amulet

OBJECTIVES

This study aimed to provide a systematic review of device-associated thrombosis (DAT) after left atrial appendage occlusion (LAAO) with the Watchman, Amplatzer Cardiac Plug, and Amulet devices.

BACKGROUND

DAT is known as a complication of LAAO but data about its clinical impact is scarce.

METHODS

A systematic review of studies evaluating the incidence, treatment and clinical implications of DAT from January 2008 to September 2015 was conducted.

RESULTS

A total of 30 studies describing DAT events were included in the analysis. The overall incidence of DAT was 3.9% (82 DAT for 2118 implanted devices). The median time from procedure to diagnosis of DAT was 1.5 months (IQR: 0-2.9). Most cases were diagnosed with transesophageal echocardiogram (TEE). The treatment consisted of low molecular weight heparin (LMWH) in 45.5% of cases, and oral anticoagulation (OAC) or other treatment modalities in 54.5%. Complete thrombus resolution was achieved in 95.0% of cases (100% with LMWH and 89.5% with OAC). Treatment duration varied greatly with a median treatment duration of 45 days (IQR: 14-135). Clinical events related to DAT consisted of neurologic events namely two transient ischemic attacks (2.4%) and four ischemic strokes (4.9%).

CONCLUSIONS

DAT is an infrequent complication of percutaneous LAAO. It occurs mainly early after the procedure and is associated with a low rate of neurological complications. In the majority of cases, diagnosis is made during follow-up imaging with TEE. Anticoagulation treatment seems to be safe and highly effective. Further studies are needed to evaluate the optimal management of DAT. © 2017 Wiley Periodicals, Inc.

Cardiac CT Angiography (CCTA) predicts left atrial appendage occluder device size and procedure outcome

AIM

To investigate the role of cardiac CT angiography (CCTA) in predicting optimal left atrial appendage (LAA) occluder size and procedure outcome.

METHODS AND RESULTS

Thirty-six patients underwent pre-procedural CCTA. CCTA and TEE LAA orifice diameters and perimeters were compared with the implanted device size. CCTA 3D configuration was correlated with procedure outcome. Watchman™ device (N = 18): diameters were 21 ± 4, 26 ± 5 and 25 ± 3 mm for TEE, CCTA and inserted device, respectively. Average perimeters were 61 ± 10, 74 ± 8 and 78 ± 11 mm for TEE, CCTA and inserted device, respectively. Better agreement with the device size was found for CCTA compared to TEE (Bland-Altman). ACP™ device (N = 15): diameters were 20 ± 5, 25 ± 4 and 23 ± 4 for TEE, CCTA and inserted device, respectively. Average perimeters were 58 ± 11, 72 ± 15 and 72 ± 13 mm for TEE, CCTA and inserted device, respectively. Excellent correlation and agreement with the device size was found for CCTA compared to TEE. CCTA perimeter >100 mm and "cactus" 3D configuration had a specificity of 96 and 81% respectively for procedure failure.

CONCLUSIONS

CCTA LAA ostial perimeter predicted better the optimal occluder size as compared with the currently used LAA TEE diameter. Moreover, CCTA 3D data may help in predicting potential complications.

Interventional left atrial appendage closure vs novel anticoagulation agents in patients with atrial fibrillation indicated for long-term anticoagulation (PRAGUE-17 study)

Atrial fibrillation (AF), with a prevalence of 1% to 2%, is the most common cardiac arrhythmia. Without antithrombotic treatment, the annual risk of a cardioembolic event is 5% to 6%. The source of a cardioembolic event is a thrombus, which is usually formed in the left atrial appendage (LAA). Prevention of cardioembolic events involves treatment with anticoagulant drugs: either vitamin K antagonists or, recently, novel oral anticoagulants (NOAC). The other (nonpharmacologic) option for the prevention of a cardioembolic event involves interventional occlusion of the LAA.

OBJECTIVE

To determine whether percutaneous LAA occlusion is noninferior to treatment with NOAC in AF patients indicated for long-term systemic anticoagulation.

STUDY DESIGN

The trial will be a prospective, multicenter, randomized noninferiority trial comparing 2 treatment strategies in moderate to high-risk AF patients (ie, patients with history of significant bleeding, or history of cardiovascular event(s), or a with CHA₂DS₂VASc ≥3 and HAS-BLED score ≥2). Patients will be randomized into a percutaneous LAA occlusion (group A) or a NOAC treatment (group B) in a 1:1 ratio; the randomization was done using Web-based randomization software. A total of 396 study participants (198 patients in each group) will be enrolled in the study. The primary end point will be the occurrence of any of the following events within 24months after randomization: stroke or transient ischemic attack (any type), systemic cardioembolic event, clinically significant bleeding, cardiovascular death, or a significant periprocedural or device-related complications.

CONCLUSION

The PRAGUE-17 trial will determine if LAA occlusion is noninferior to treatment with NOAC in moderate- to high-risk AF patients.

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.

Recent advances in the understanding and management of atrial fibrillation: a focus on stroke prevention

Atrial fibrillation (AF) is associated with an increased risk of stroke compared with the general population. It is anticipated that by 2030 an estimated 14-17 million patients will be diagnosed with this most prevalent arrhythmia within the European Union. AF-related stroke confers a higher mortality and morbidity risk, and thus early detection and assessment for the initiation of effective stroke prevention with oral anticoagulation (OAC) is crucial. Recent guidelines point to the use of non-vitamin K antagonist OACs (NOACs) where appropriate in stroke prevention of patients with non-valvular AF. At present, there are four NOACS available, with no direct head-to-head comparisons to suggest the superiority of one drug over another. Simple and practical risk assessment tools have evolved over the years to facilitate stroke and bleeding risk assessment in busy clinics and wards to aid decision-making. At present, the CHA ₂DS ₂VASc (congestive heart failure, hypertension, age 65-74/>75, diabetes mellitus, stroke/transient ischemic attack/thromboembolism, vascular disease, female sex) score is recommended by many international guidelines as a simple and practical method of assessing stroke risk in such patients. Alongside this, use of the HAS BLED (hypertension systolic blood pressure >160 mmHg, abnormal liver/renal function [with creatinine ≥200 μmol/L], stroke, bleeding history or predisposition, labile international normalized ratio [range <60% of the time], elderly [>65], concomitant drugs/alcohol) score aims to identify patients at high risk of bleeding for more regular review and follow-up and draws attention to potentially reversible bleeding risk factors. The aim of this review article is to provide an overview of recent advances in the understanding and management of AF with a focus on stroke prevention.

Characterization of Cerebrovascular Events After Left Atrial Appendage Occlusion

Cardioembolic strokes are generally more lethal and disabling than other source of strokes. Data from PROTECT AF (Watchman Left Atrial Appendage Closure Technology for Embolic Protection in Patients With Atrial Fibrillation) suggest that strokes after left atrial appendage occlusion (LAAO) with the Watchman device are less disabling than those in the warfarin group. No data assessing the severity of strokes after LAAO with the AMPLATZER Cardiac Plug (ACP) are available. The objective of the study was to evaluate the severity of cerebrovascular events after LAAO with the ACP in a population mostly characterized by an absolute or relative contraindication to oral anticoagulation. Data from the ACP multicenter registry were analyzed. Disabling strokes were defined as those with a modified Rankin score of 3 to 6 at 90 days after the event. A total of 1,047 subjects were included. The mean age and CHADS₂ score were 75 ± 8 years and 2.8 ± 1.3, respectively. Procedural success was achieved in 97.3% and 4.9% of the patients presented procedural major adverse events. Clinical follow-up was complete in 98.2% of patients with a median of 13 months. There were 9 strokes (0.9%), 9 transient ischemic attacks (0.9%), and no intracranial hemorrhages (0%) at follow-up. After excluding 2 patients with pre-LAAO disability, functional assessment showed disabling events in 3 (19%) of the remaining 16 patients. The median time of presentation was 420 days (interquartile range 234 to 671) after LAAO, and 17 patients (94%) were on single-antiplatelet therapy when the event occurred. According to our results, cerebrovascular events after LAAO with the ACP system were infrequent and mostly nondisabling.

Left atrial appendage closure: outcomes and challenges

Whereas the left atrial appendage plays a rather minor role under physiological circumstances, it gains an importance in patients with atrial fibrillation. Compelling evidence has revealed that the left atrial appendage is implicated as the source of thrombus in the vast majority of strokes in atrial fibrillation. Oral anticoagulation remains the standard of care for stroke prevention in atrial fibrillation; nevertheless, this treatment has several limitations and is often contraindicated, particularly in the elderly population in whom the risk of stroke is high. Therefore, occluding the left atrial appendage is a logical approach to prevent thrombus formation and subsequent cardioembolic events in these patients. We present a review of clinical outcomes of patients with atrial fibrillation undergoing left atrial appendage closure and the challenges faced in this field.

Outcomes and costs of left atrial appendage closure from randomized controlled trial and real-world experience relative to oral anticoagulation

AIMS

The aim of this study was to analyse randomized controlled study and real-world outcomes of patients with non-valvular atrial fibrillation (NVAF) undergoing left atrial appendage closure (LAAC) with the Watchman device and to compare costs with available antithrombotic therapies.

METHODS AND RESULTS

Registry data of LAAC from two centres were prospectively collected from 110 patients with NVAF at risk of stroke, suitable and unsuitable for long-term anticoagulation (age 71.3 ± 9.2 years, CHADS2 2.8 ± 1.2, CHA2DS2-VASc 4.5 ± 1.6, and HAS-BLED 3.8 ± 1.1). Outcomes from PROTECT AF and registry study LAAC were compared with warfarin, dabigatran, rivaroxaban, apixaban, aspirin, and no treatment using a network meta-analysis. Costs were estimated over a 10-year horizon. Uncertainty was assessed using sensitivity analyses. The procedural success rate was 92% (103/112). Follow-up was 24.1 ± 4.6 months, during which annual rates of stroke, major bleeding, and all-cause mortality were 0.9% (2/223 patient-years), 0.9% (2/223 patient-years), and 1.8% (4/223 patient-years), respectively. Anticoagulant therapy was successfully stopped in 91.2% (93/102) of implanted patients by 12 months. Registry study LAAC stroke and major bleeding rates were significantly lower than PROTECT AF results: mean absolute difference of stroke, 0.89% (P = 0.02) and major bleeding, 5.48% (P < 0.001). Left atrial appendage closure achieved cost parity between 4.9 years vs. dabigatran 110 mg and 8.4 years vs. warfarin. At 10 years, LAAC was cost-saving against all therapies (range £1162-£7194).

CONCLUSION

Left atrial appendage closure in NVAF in a real-world setting may result in lower stroke and major bleeding rates than reported in LAAC clinical trials. Left atrial appendage closure in both settings achieves cost parity in a relatively short period of time and may offer substantial savings compared with current therapies. Savings are most pronounced among higher risk patients and those unsuitable for anticoagulation.

The impact of surgical left atrial appendage amputation/ligation on stroke prevention in patients undergoing off-pump coronary artery bypass grafting

Stroke is a major adverse event in patients developing atrial fibrillation (AF) after cardiac surgery. Surgical left atrial appendage amputation/ligation (LAA-A/L) during off-pump coronary artery bypass grafting (OPCAB) is routinely performed in our institution. We analyzed 578 consecutive patients (mean age 69 years, male 82%) undergoing OPCAB with or without concomitant LAA-A/L from 2011 to 2014 at our institution in a prospective observational manner. The safety and efficacy of the concomitant LAA-A/L on preventing early (<30 days) and overall postoperative stroke were examined. A total of 193 patients (33.4%) underwent LAA-A/L, consisting of amputation in 154 and ligation in 39 patients (80 and 20% of the cases, respectively). Preoperative characteristics, operative time, requirement of blood transfusion, and 30-day mortality were not significantly different between those with and without LAA-A/L. The incidences of postoperative AF and early and overall stroke were not significantly different between the groups in the analysis based on a total cohort. In a subanalysis of patients without LAA-A/L, early and overall stroke occurred more frequently in those developing postoperative AF than those without AF (2.8 vs. 0%; p = 0.005, 6.2 vs. 1.5%; p = 0.017, respectively), while in patients receiving LAA-A/L, stroke incidences did not differ between those with and without AF. Multivariate logistic regression showed postoperative AF without LAA-A/L as the only independent positive predictor of overall stroke (OR 3.69, p = 0.03). Concomitant LAA-A/L with OPCAB can safely prevent postoperative stroke occurrence in case patients develop AF, the most common arrhythmia associated with stroke.

Post-Approval U.S. Experience With Left Atrial Appendage Closure for Stroke Prevention in Atrial Fibrillation

BACKGROUND

Left atrial appendage closure (LAAC) was approved by the U.S. Food and Drug Administration (FDA) as a stroke prevention alternative to warfarin for patients with nonvalvular atrial fibrillation. However, clinical decision-making is confounded by the fact that although LAAC attenuates the anticoagulant-related lifetime risk of bleeding, implantation is associated with upfront complications. Thus, enthusiasm for LAAC as a treatment option has been appropriately tempered, particularly as the therapy is introduced beyond the clinical trial sites into general clinical practice.

OBJECTIVES

This study evaluated the acute procedural performance and complication rates for all cases performed in the United States since FDA approval.

METHODS

In the absence of a formal national clinical registry since regulatory approval in March 2015, we obtained procedural data on implantation procedures. Every LAAC procedure requires the presence of a manufacturer clinical specialist and for procedural parameter and periprocedural complication data to be collected using a standardized process and forms.

RESULTS

In 3,822 consecutive cases, implantation was successful in 3,653 (95.6%), with a median procedure time of 50 min (range 10 to 210 min). Implanting physicians performing these procedures (n = 382) included 71% new, nonclinical trial implanters, who performed 50% of the procedures. Procedural complication rates included 39 pericardial tamponades (1.02%) (24 treated percutaneously, 12 surgically, and 3 fatal); 3 procedure-related strokes (0.078%); 9 device embolizations (0.24%) (6 requiring surgical removal); and 3 procedure-related deaths (0.078%).

CONCLUSIONS

Despite a large fraction of previously inexperienced operators, in the real-world post-FDA approval experience of LAAC, procedural success was high and complication rates were low.

Percutaneous left atrial appendage occlusion using different technologies in the United Kingdom: A multicenter registry

OBJECTIVES

This study aimed at assessing the feasibility and long-term efficacy of left atrial appendage occlusion (LAAO) in a "real world" setting.

BACKGROUND

Although LAAO has recently emerged as an alternative to oral anticoagulants in patients with atrial fibrillation for the prevention of thromboembolic stroke, "real world" data about the procedure with different devices are lacking.

METHODS

Eight centers in the United Kingdom contributed to a retrospective registry for LAAO procedures undertaken between July 2009 and November 2014.

RESULTS

A total of 371 patients (72.9 ± 8.3 years old, 88.9% males) were enrolled. The overall procedure success was 92.5%, with major events in 3.5% of cases. The device choice was Watchman in 63% of cases, Amplatzer Cardiac Plug in 34.7%, Lariat in 1.7%, and Coherex WaveCrest in 0.6%. A significant improvement in procedure success (from 89.2% to 95.7%; P = 0.018) and reduction of acute major complications (from 6.5% to 0.5%; P = 0.001) were observed between procedures in the first and the second half of the recruitment time. An annual 90.1% relative risk reduction (RRR) for ischemic stroke, an 87.2% thromboembolic events RRR, and a 92.9% major bleeding RRR were observed, if compared with the predicted annual risks based on CHADS2, CHA2DS2-Vasc, and HAS-BLED scores, respectively, over a follow-up period of 24.7 ± 16.07 months.

CONCLUSIONS

LAAO can be performed safely in a real world setting with good implant success rates and procedural outcomes. The long-term benefits of the procedure are reassuring in terms of both ischemic events and avoidance of severe bleeding associated with anticoagulation in this patient group. © 2016 Wiley Periodicals, Inc.

Percutaneous left atrial appendage closure devices: safety, efficacy, and clinical utility

Atrial fibrillation (AF) is the most common arrhythmia treated in the clinical practice. One of the major complications of AF is a thromboembolic cerebral ischemic event. Up to 20% of all strokes are caused by AF. Thromboembolic cerebral ischemic event in patients with AF occurs due to atrial thrombi, mainly from the left atrial appendage (LAA). Prevention of clot formation with antiplatelet agents and especially oral anticoagulants (vitamin K antagonists or newer oral anticoagulants) has been shown to be effective in reducing the stroke risk in patients with AF but has several drawbacks with (major) bleedings as the most important disadvantage. Therefore, physical elimination of the LAA, which excludes the site of clot formation by surgical or percutaneous techniques, might be a good alternative. In this review, we discuss the safety, efficacy, and clinical utility of the Watchman™ LAA closure device.

Left atrial appendage closure: A single center experience and comparison of two contemporary devices

OBJECTIVES

To compare indications and clinical outcomes of two contemporary left atrial appendage (LAA) percutaneous closure systems in a "real-world" population.

BACKGROUND

Percutaneous LAA occlusion is an emerging therapeutic option for stroke prevention in atrial fibrillation. Some questions however remain unanswered, such as the applicability of results of randomized trials to current clinical practice. Moreover, currently available devices have never been directly compared.

METHODS

We retrospectively analyzed consecutive patients who underwent LAA closure at San Raffaele Hospital, Milan, Italy between 2009 and 2015. Clinical indications and device selection were left to operators' decision; routine clinical and transesophageal echocardiography (TEE) follow-up was performed.

RESULTS

One-hundred and sixty-five patients were included in the study, of which 99 were treated with the Amplatzer Cardiac Plug (ACP) and 66 with the Watchman system. During the follow-up period (median 15 months, interquartile range 6-26 months) five patients died. The incidence of ischemic events was low, with one patient suffering a transient ischemic attack and no episodes recorded of definitive strokes. Twenty-six leaks ≥1 mm were detected (23%); leaks were less common with the ACP and with periprocedural three-dimensional TEE evaluation, but were not found to correlate with clinical events. Clinical outcomes were comparable between the two devices.

CONCLUSIONS

Our data show excellent safety and efficacy of LAA closure, irrespectively of the device utilized, in a population at high ischemic and hemorrhagic risk. The use of ACP and 3D-TEE minimized the incidence of residual leaks; however, the clinical relevance of small peri-device flow warrants further investigation. © 2016 Wiley Periodicals, Inc.

Thrombus Formation After Left Atrial Appendage Occlusion With the Amplatzer Amulet Device

OBJECTIVES

This study sought to define the ideal post-procedural anticoagulant regime and to systematically study the incidence of device-related thrombus.

BACKGROUND

Left atrial appendage occlusion (LAAo) is an alternative to life-long oral anticoagulation in selected patients with atrial fibrillation.

METHODS

This study included 24 atrial fibrillation patients (ages 79 ± 8 years; 75% male, CHA₂DS₂VASc [Congestive Heart Failure, Hypertension, Age ≥75 Years, Diabetes Mellitus, Previous Stroke or Transient Ischemic Attack or Thromboembolism, Vascular Disease, Age 65 to 74 Years. Sex] score: 4.3 ± 1.5, HAS-BLED [Hypertension, Abnormal Renal and Liver Function, Stroke, Bleeding, Labile International Normalized Ratio, Elderly, Drugs or Alcohol] score: 3.6 ± 0.8) after LAAo with the use of the Amplatzer Amulet system. Dual antiplatelet therapy for 3 months was prescribed in 95.6% of the cases.

RESULTS

Transesophageal echocardiography identified a high rate of device adherent thrombi (16.7%, n = 4 of 23) after a mean of 11.0 ± 8.2 weeks. Thrombus formation occurred under dual antiplatelet therapy (3 of 4) or clopidogrel monotherapy (1 of 4). When compared with patients without thrombi, echocardiography showed higher degrees of spontaneous echo contrast grades within the LAA (3.0 ± 1.0 vs. 1.3 ± 1.1), lower LAA peak emptying velocities (17.5 ± 5.0 cm/s vs. 48.3 ± 21.1 cm/s), and decreased left ventricular function (39 ± 10% vs. 50 ± 13%) in patients with device-related thrombus. All thrombi were observed within the untrabeculated region of the LAA ostium between the left upper pulmonary vein ridge and the occluder disc, indicating suboptimal LAA occlusion.

CONCLUSIONS

Device-related thrombus is a frequent finding after LAAo with the Amplatzer Amulet device (St. Jude Medical, St. Paul, Minnesota). Our results emphasize the need for an optimized post-LAAo anticoagulation regimen, a revised implantation strategy, and possibly modified patient selection criteria.

Left atrial appendage and pulmonary artery anatomic relationship by cardiac-gated computed tomography: Implications for late pulmonary artery perforation by left atrial appendage closure devices

BACKGROUND

Delayed pulmonary artery (PA) perforation and tamponade caused by implantable left atrial appendage (LAA) closure devices has been reported in patients with close proximity between these structures. The LAA and PA anatomic relationship (LAA-PAar) has not been analyzed systematically.

OBJECTIVE

The purpose of this study was to identify LAA-PAar variants potentially susceptible to this complication using cardiac-gated computed tomography angiography.

METHODS

We studied 100 consecutive patients with atrial fibrillation undergoing cardiac-gated computed tomography angiography of the left atrium. The LAA-PAar was classified into 3 types on the basis of the location, length, and thickness of the segment of contact between the PA and/or its branches and the LAA: type 1, no contact; type 2, contact involving the proximal LAA (defined as the proximal 15 mm extending into the LAA from its ostium, or the LAA proximal to the first major bend arising <15 mm from the ostium); and type 3, contact limited to the distal LAA.

RESULTS

LAA-PAar types 1, 2, and 3 were present in 7 (7%), 28 (28%), and 65 (65%) patients, respectively. For LAA-PAar type 2, the mean contact segment thickness and length were 0.6 ± 0.3 and 18.1 ± 10.6 mm, respectively. For LAA-PAar type 3, the distance between the LAA orifice and the segment of contact was <30 mm in 52 patients (80%).

CONCLUSION

In this series, the LAA came in direct contact with the main PA in the majority of patients. Contact involved the proximal LAA (where the fixation components of most LAA closure devices are positioned) in 28% of patients, posing potential vulnerability to PA perforation.

Imaging Techniques in Percutaneous Cardiac Structural Interventions: Atrial Septal Defect Closure and Left Atrial Appendage Occlusion

Because of advances in cardiac structural interventional procedures, imaging techniques are playing an increasingly important role. Imaging studies show sufficient anatomic detail of the heart structure to achieve an excellent outcome in interventional procedures. Up to 98% of atrial septal defects at the ostium secundum can be closed successfully with a percutaneous procedure. Candidates for this type of procedure can be identified through a systematic assessment of atrial septum anatomy, locating and measuring the size and shape of all defects, their rims, and the degree and direction of shunting. Three dimensional echocardiography has significantly improved anatomic assessments and the end result itself. In the future, when combined with other imaging techniques such as cardiac computed tomography and fluoroscopy, 3-dimensional echocardiography will be particularly useful for procedure guidance. Percutaneous closure of the left atrial appendage offers an alternative for treating patients with atrial fibrillation and contraindication for oral anticoagulants. In the future, the clinical focus may well turn to stroke prevention in selected patients. Percutaneous closure is effective and safe; device implantation is successful in 94% to 99% of procedures. However, the procedure requires an experienced cardiac structural interventional team. At present, 3-dimensional echocardiography is the most appropriate imaging technique to assess anatomy suitability, select device type and size, guide the procedure alongside fluoroscopy, and to follow-up the patient afterwards.

Left atrial appendage closure: patient, device and post-procedure drug selection

Left atrial appendage closure (LAAC), a device-based therapy for stroke prevention in patients with atrial fibrillation, is considered an alternative to oral anticoagulation therapy, particularly for patients at high risk of bleeding. Proof of concept has been demonstrated by the PROTECT AF and PREVAIL trials which evaluated the WATCHMAN device (Boston Scientific, Marlborough, MA, USA) versus warfarin, showing favourable outcome for the device group. The most commonly used devices for LAAC are the WATCHMAN and its successor, the WATCHMAN FLX (Boston Scientific) and the AMPLATZER Cardiac Plug and more recently the AMPLATZER Amulet device (both St. Jude Medical, St. Paul, MN, USA). The procedure is typically performed via a transseptal puncture under fluoroscopic and echocardiographic guidance. Technically, it is considered quite demanding due to the anatomic variability and fragility of the appendage. Careful material manipulation, adequate operator training, and good cardiac imaging and device sizing allow a safe, uneventful procedure. Post-procedure antithrombotic drug selection is based on the patient's history, indication and quality of LAAC.

Efficacy and Safety of Percutaneous Left Atrial Appendage Occlusion for Stroke Prevention in Nonvalvular Atrial Fibrillation: A Meta-analysis of Contemporary Studies

BACKGROUND

Percutaneous left atrial appendage (LAA) occlusion has emerged as an important treatment for patients with nonvalvular atrial fibrillation (NVAF) who are at high stroke risk and have contraindications for anticoagulation. However, literature about the efficacy and safety of LAA occlusion is minimal to date. We performed a meta-analysis to assess the rates of stroke events and adverse events for patients treated with occlusion devices.

METHODS

We conducted a comprehensive search on PubMed, Web of Science, OVID, SCOPUS databases and the Cochrane Central Register of Controlled Trials databases from inception to December 31, 2014 for studies of percutaneous LAA occlusion for patients with NVAF. Studies were included in the meta-analysis if at least 10 patients were studied with six months or more of follow-up period and reported at least one outcome of interest.

RESULTS

A total of 2779 patients in 25 studies were included in the meta-analysis. Two were randomised control trials (RCTs), others were cohort studies. The adjusted incidence rate of stroke was 1.2/100 person-years (PY) (95% confidence interval [CI], 0.9-1.6/100 PY). The ischaemic and haemorrhagic stroke rates were 1.1/100 PY (95% CI, 0.8-1.4/100 PY) and 0.2/100 PY (95% CI, 0.1-0.3/100 PY), respectively. The combined efficacy outcomes (stroke or transient ischaemic attacks [TIAs], systemic embolism, or cardiovascular death) was 2.7/100 PY (95% CI, 1.9- 3.4/100 PY). Major bleeding and pericardial effusions were the most commonly observed adverse events at a rate of 2.6% (95% CI, 1.5%-3.6%) and 2.5% (95% CI, 1.8%-3.2%), respectively.

CONCLUSIONS

Percutaneous LAA occlusion is a reasonably efficacious and safe therapeutic option in patients with NVAF who are at high risk for stroke and contraindicated for long-term anticoagulation.

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.

Left Atrial Appendage Closure for Stroke Prevention: Devices, Techniques, and Efficacy

Left atrial appendage closure can be performed either surgically or percutaneously. Surgical approaches include direct suture, excision and suture, stapling, and clipping. Percutaneous approaches include endocardial, epicardial, and hybrid endocardial-epicardial techniques. Left atrial appendage anatomy is highly variable and complex; therefore, preprocedural imaging is crucial to determine device selection and sizing, which contribute to procedural success and reduction of complications. Currently, the WATCHMAN is the only device that is approved for left atrial appendage closure in the United States.

Left Atrial Appendage Occlusion in Non-Valvular Atrial Fibrillation in a Korean Multi-Center Registry

BACKGROUND

The aim of this study was to evaluate clinical outcome after left atrial appendage (LAA) occlusion in real clinical practice and compare between Amplatzer cardiac plug (ACP) and Watchman.

METHODS AND RESULTS

From October 2010 to February 2015, 96 successful LAA occlusion procedures were performed using either ACP (n=50) or Watchman device (n=46) in non-valvular atrial fibrillation (AF) patients (59 male; age, 65.1±9.4 years; CHADS2, 2.5±1.2; CHA2DS2-VASC, 3.9±1.6; HAS-BLED, 2.7±1.3). The procedure success rate was 96.8%. There were serious complications in 4 patients (4.1%; 2 cardiac tamponade, 1 device embolization, and 1 major bleed). The anticoagulation cessation rate after 6 weeks was 92.7%. During mean 21.9-month follow-up, the incidence of death, stroke, systemic embolization and major bleeding was 5.2%, 4.2%, 0% and 1.0%, respectively. On transesophageal echocardiography of 93 patients within 6 months after the procedure, 24 residual leaks were observed (25.8%; 2 mild, 18 moderate, and 4 major). Clinical outcome was similar for the 2 devices, but peridevice leakage was more frequent with the Watchman than the ACP.

CONCLUSIONS

LAA occlusion was feasible in non-valvular AF patients with high risk of stroke and hemorrhage. The ACP and Watchman devices were similar in terms of procedural and clinical outcomes. (Circ J 2016; 80: 1123-1130).

Implant success and safety of left atrial appendage closure with the WATCHMAN device: peri-procedural outcomes from the EWOLUTION registry

Aims  Left atrial appendage closure is a non-pharmacological alternative for stroke prevention in high-risk patients with non-valvular atrial fibrillation. The objective of the multicentre EWOLUTION registry was to obtain clinical data on procedural success and complications, and long-term patient outcomes, including bleeding and incidence of stroke/transient ischaemic attack (TIA). Here, we report on the peri-procedural outcomes of up to 30 days.

Methods and results  Baseline/implant data are available for 1021 subjects. Subjects in the study were at high risk of stroke (average CHADS ₂ score: 2.8 ± 1.3, CHA ₂ DS ₂ -VASc: 4.5 ± 1.6) and moderate-to-high risk of bleeding (average HAS-BLED score: 2.3 ± 1.2). Almost half of the subjects (45.4%) had a history of TIA, ischaemic stroke, or haemorrhagic stroke; 62% of patients were deemed unsuitable for novel oral anticoagulant by their physician. The device was successfully deployed in 98.5% of patients with no flow or minimal residual flow achieved in 99.3% of implanted patients. Twenty-eight subjects experienced 31 serious adverse events (SAEs) within 1 day of the procedure. The overall 30-day mortality rate was 0.7%. The most common SAE occurring within 30 days of the procedure was major bleeding requiring transfusion. Incidence of SAEs within 30 days was significantly lower for subjects deemed to be ineligible for oral anticoagulation therapy (OAT) compared with those eligible for OAT (6.5 vs. 10.2%, P = 0.042).

Conclusion  Left atrial appendage closure with the WATCHMAN device has a high success rate in complete LAAC with low peri-procedural risk, even in a population with a higher risk of stroke and bleeding, and multiple co-morbidities. Improvement in implantation techniques has led to a reduction of peri-procedural complications previously limiting the net clinical benefit of the procedure.

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.

Efficacy and safety of percutaneous left atrial appendage closure to prevent thromboembolic events in atrial fibrillation patients with high stroke and bleeding risk

AIMS

The randomized PROTECT AF trial demonstrated non-inferiority of left atrial appendage (LAA) closure to oral anticoagulation with warfarin. Current guidelines give a class IIb recommendation for LAA closure. We evaluated the efficacy and safety of LAA closure in a consecutive series of non-valvular atrial fibrillation patients with contraindications to long-term oral anticoagulation or at high bleeding risk.

METHODS AND RESULTS

101 consecutive non-valvular atrial fibrillation patients (age 74.7 ± 7.5 years) at high risk for stroke (CHA2DS2-VASc Score 4.4 ± 1.6) and high bleeding risk (HAS-BLED Score 4.2 ± 1.3) received LAA closure with either the Watchman closure device (n = 38) or the Amplatzer cardiac plug (n = 63). Dual antiplatelet therapy with aspirin and clopidogrel was recommended for 3-6 months after device implantation, followed by long-term antiplatelet therapy with aspirin. No anticoagulation was given after device implantation. Mean follow-up was 400 days. One patient (1 %) experienced a transient ischemic attack, and two patients (2 %) suffered from ischemic stroke. While on recommended antiplatelet therapy, bleeding occurred in 12/101 patients (12 %). Bleeding was significantly reduced with 3 compared with 6 months dual antiplatelet therapy (3.0 vs. 16.2 %, p < 0.05) while ischemic or thrombotic events were similar.

CONCLUSION

Left atrial appendage closure in patients with non-valvular atrial fibrillation and high risk for stroke and bleeding events effectively prevented stroke and reduced cerebral ischemic events compared to expected stroke rate according to CHA2DS2-VASc Score. Dual antiplatelet therapy for 3 months reduced the rate of bleeding events compared to 6 months therapy with no increase of thrombotic events.

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.

Cardiac CT angiography for device surveillance after endovascular left atrial appendage closure

AIMS

Left atrial appendage (LAA) device imaging after endovascular closure is important to assess for device thrombus, residual leak, positioning, surrounding structures, and pericardial effusion. Cardiac CT angiography (CCTA) is well suited to assess these non-invasively.

METHODS AND RESULTS

We report our consecutive series of non-valvular atrial fibrillation patients who underwent CCTA post-LAA closure with Amplatzer Cardiac Plug (ACP), Amulet (second generation ACP), or WATCHMAN devices. Patients underwent CCTA typically 1-6 months post-implantation. Prospective cardiac-gated CCTA was performed with Toshiba 320-detector or Siemens 2nd generation 128-slice dual-source scanners, and images interpreted with VitreaWorkstation™. GFR <30 mL/min/1.73 m(2) was an exclusion. We assessed for device thrombus, residual LAA leak, device embolization, position, pericardial effusion, optimal implantation, and device lobe dimensions. Forty-five patients underwent CCTA at median 97 days post-LAA closure (18 ACP, 9 Amulet, 18 WATCHMAN). Average age was 75.5 ± 8.9 years, mean CHADS2 score 3.1 ± 1.3, and CHADS-VASc score 4.9 ± 1.6. All had contraindications to oral anticoagulation. Post-procedure, 41 (91.1%) were discharged on DAPT. There was one device embolization (ACP, successfully retrieved percutaneously) and one thrombus (WATCHMAN, resolved with 3 months of warfarin). There were two pericardial effusions, both pre-existing and not requiring intervention. Residual leak (patency) was seen in 28/44 (63.6%), and the mechanisms of leak were readily identified by CCTA (off-axis device, gaps at orifice, or fabric leak). Mean follow-up was 1.2 ± 1.1year, with no death, stroke, or systemic embolism.

CONCLUSION

CCTA appears to be a feasible alternative to transoesophageal echocardiography for post-LAA device surveillance to evaluate for device thrombus, residual leak, embolization, position, and pericardial effusion.