Non-surgical left atrial appendage closure for stroke prevention in atrial fibrillation

Non-Surgical Left Atrial Appendage Closure for Stroke Prevention in Atrial Fibrillation. The most feared complication associated with atrial fibrillation (AF) is stroke, the risk of which increases with advanced age. Because of its complex anatomy and diminished blood flow during AF, the left atrial appendage (LAA) has been a common site of left atrial thrombi and presumed source of thromboembolism. Systemic anticoagulation to treat what may be largely a localized phenomenon is associated with significant complications. Newer anticoagulation agents hold great promise in facilitating dosing and eliminating drug and food interactions, but do not eliminate bleeding risk. These challenges have led to interest in mechanical exclusion of the LAA as a means of preventing thromboembolism in AF. Although surgery permits greater visualization and management of complications, the potential morbidity has limited adoption in often-frail elderly patients. In this paper, we review the current state of percutaneous left atrial exclusion for stroke prevention in AF, and the strengths and limitations of each of these strategies. The nonsurgical approaches to excluding the LAA from the central circulation can be divided into 3 broad categories: transseptally placed devices, percutaneous epicardial approach, and hybrid approaches. The availability of several approaches will allow physician selection of the optimal approach for a given patient based on clinical, physiological, and anatomical considerations. LAA exclusion stands to become an increasingly attractive option for patients with nonvalvular AF because it can be offered to elderly AF patients, and eliminates the long-term cumulative bleeding risks and adherence challenge of anticoagulants.     

Percutaneous left atrial appendage transcatheter occlusion for patients with atrial fibrillation unable to take warfarin

Anticoagulation with warfarin for atrial fibrillation is frequently difficult. A transcatheter method to exclude the left atrial appendage from the circulation could be an advantage for selected patients. Percutaneous left atrial appendage transcatheter occlusion is a catheter-based delivery of an occlusive nitinol cage to the neck of the left atrial appendage. The device obliterates the left atrial appendage, eliminating a major source of thromboembolism. Animal studies have confirmed device coverage with an endocardial layer within 6 months and distal atrial appendage fibrosis. A standard transseptal approach from the right femoral vein is used. Patients leave the hospital within 1 day. Six-month follow-up of European and US safety and efficacy trials has shown favorable outcomes in minimizing thromboembolic events and few complications related to placement or healing of the device. Further clinical studies will be needed to establish which patients will be best treated with this device.     

Predictors of left atrial appendage clot: a transesophageal echocardiographic study of left atrial appendage function in patients with severe mitral stenosis

BACKGROUND: The purpose of this study was to prospectively evaluate a large group of consecutive, non-anticoagulated patients with severe rheumatic mitral stenosis and to analyze the left atrial appendage function in relation to left atrial appendage clot and spontaneous echo contrast formation. METHODS AND RESULTS: We prospectively studied left atrial appendage function in 200 consecutive patients with severe mitral stenosis who underwent transesophageal echocardiography and correlated it with spontaneous echo contrast and left atrial appendage clot. The mean age was 30.2 +/- 9.4 years. Fifty-five (27.5%) patients were in atrial fibrillation. Left atrial appendage clot was present in 50 (25%) patients and 113 (56.5%) had spontaneous echo contrast. The older age, increased duration of symptoms, atrial fibrillation, spontaneous echo contrast, larger left atrium, depressed left atrial appendage function and type II and III left atrial appendage flow patterns correlated significantly (p<0.05) with the left atrial appendage clot. Left atrial appendage ejection fraction was significantly less in patients with clot (21.8 +/- 12.8% v. 39.1 +/- 13.2%, p<0.0001) and in those with spontaneous echo contrast (30.3 +/- 16.2 % v. 40.3 +/- 11.8%, p<0.001). Left atrial appendage filling (18.0 +/- 11.7 v. 27.6 +/- 11.8 cm/s, p <0.0001) and emptying velocities (15.4 +/- 7.0 v. 21.5 +/- 9.6 cm/s, p<0.001) and filling (1.4 +/- 1.0 v. 2.5 +/- 1.4 cm, p<0.0001) and emptying (1.5 +/- 1.2 v. 2.1 +/- 1.2 cm, p <0.05) velocity time integrals were also significantly lower in patients with clot as compared to those without clot. On multivariate regression analysis, atrial fibrillation (odds ratio 6.68, 95% CI 1.85-24.19, p=0.003) and left atrial appendage ejection fraction (odds ratio 1.06, 95% CI 1.00 - 1.11, p=0.04) were the only two independent predictors of clot formation. Incidence of clot was 62.59% in patients with left atrial appendage ejection fraction < or = 25% as compared to 10.4% in those having left atrial appendage ejection fraction >25%. Similarly patients with spontaneous echo contrasthadlower filling (21.7 +/- 11.5 v. 29.4 +/- 12.7 cm/s, p<0.0001) and emptying (17.0 +/- 8.1 v. 23.9 +/- 10.9 cm/s, p<0.0001) velocities, as well as filling (1.9 +/- 1.3 v. 2.7 +/- 1.3 cm, p<0.01) and emptying (1.7 +/- 1.0 v. 2.3 +/- 1.4 cm, p<0.01) velocity time integrals as compared to patients without spontaneous echo contrast. In a subgroup of the patients with normal sinus rhythm, the left atrial appendage ejection fraction was significantly less in patients with clot compared to those without clot (31.2 +/- 13.2 v. 41.3 +/- 11.5 %, p<0.01). CONCLUSIONS: In the patients with severe mitral stenosis, besides atrial fibrillation, a subgroup of patients in normal sinus rhythm with depressed left atrial appendage function (left atrial appendage ejection fraction < or = 25%) had a higher risk of clot formation in left atrial appendage and these patients should be routinely anticoagulated for prevention of clot formation.     

Is left atrial appendage occlusion useful for prevention of stroke or embolism in atrial fibrillation?

Since in atrial fibrillation more than 90% of the thrombi are located in the left atrial appendage, an “elimination” of the left atrial appendage, either by resection or occlusion, seems an attractive alternative to oral anticoagulation. Although frequently regarded as an useless appendage, data from animal and human investigations show that the left atrial appendage may play an important role in the maintenance and regulation of the cardiac function, especially in arterial hypertension, atrial fibrillation, coronary heart disease, valvular heart disease and heart failure. Elimination of the left atrial appendage may impede thirst in hypovolemia, deteriorate hemodynamic responses to volume or pressure overload, decrease cardiac output and promote heart failure. Instead of preventing stroke, the consequences of left atrial appendage elimination may create new risk factors for stroke and thus might induce more harm than benefit to patients with atrial fibrillation. As long as the physiologic and pathophysiologic role of the left atrial appendage is not fully understood, left atrial appendage elimination should not be an alternative to oral anticoagulation.     

经皮左心耳封堵术在非瓣膜性心房颤动患者卒中预防中的应用

心房颤动(atrial fibrillation,AF)导致的卒中很常见,而且常常是灾难性的.尽管口服抗凝药是预防栓塞性卒中的基石,但它们也存在许多局限性,而且并非所有患者均能长期耐受.左心耳已被认定为非瓣膜性AF患者血栓形成的来源.目前已研发出多种左心耳封堵装置,并成功用于非瓣膜性AF患者的卒中预防,且围手术期并发症较少.文章对经皮左心耳封堵术在非瓣膜性AF患者卒中预防方面的应用进行了综述.     

Percutaneous transcatheter left atrial appendage exclusion in atrial fibrillation

Stroke is one of the leading causes of mortality, morbidity and serious disability in the developed world. Atrial fibrillation (AF), one of the most common cardiac arrhythmias, is a well-known predisposing factor for stroke, raising the risk significantly. Oral anticoagulation with warfarin is currently the most effective therapy for stroke risk reduction; however, this therapy increases the risk of bleeding and is often underutilized, contraindicated, or when administered, often subtherapeutic. It has been documented that the left atrial appendage (LAA) is the main source of left atrial thrombus, especially in non-rheumatic AF. Therefore, LAA exclusion may reduce the risk of stroke in AF, and retrospective surgical data have demonstrated a reduced risk of embolic events if surgical LAA exclusion was also performed during mitral valve replacement. Recently, several less invasive percutaneous transcatheter techniques of LAA exclusion - the PLAATO device, the Watchman device, and the Amplatzer Septal Occluder - have been employed with initially encouraging results. There is currently an ongoing randomized trial comparing percutaneous LAA exclusion to long-term oral anticoagulation therapy. Until such data are available, however, oral anticoagulation should remain the standard of care for stroke prevention in patients with AF.     

心房颤动电转复后左心耳顿抑的预测因子

目的研究非瓣膜病心房颤动(房颤)患者中,心脏电转复后左心耳顿抑的危险因素与预测因子.方法 68例房颤电转复成功患者,分为左心耳顿抑组与对照组,通过单因素及多元逐步逻辑回归分析,将临床和超声影像学指标作为待选变量,对电转复后左心耳顿抑的危险因素进行研究.结果单因素分析发现,左心耳顿抑组与对照组间差异有统计学意义的指标有房颤持续时间[(10.6±15.6)周vs(22.0±20.1)周,P＜0.05]、左心房内径[(43.8±7.7)mm vs(48.5±6.2)mm,P＜0.01)]、左心房排空分数[(0.32±0.08)vs(0.27±0.09),P＜0.05]、左心室射血分数[(0.50±0.06)vs(0.46±0.06),P＜0.01]、最大复律能量[(96.8±65.8)J vs(156.8±100.8)J,P＜0.01]、累积转复能量[(146.8±142.6)J vs(290.5±242.1)J,P＜0.01]和电转复次数[(1.7±0.9)次vs(2.4±1.2)次,P＜0.05].多元逐步逻辑回归分析发现,房颤持续时间(β＝0.105,P＜0.01)、左心房内径(β＝0.196,P＜0.01)、左心室射血分数(β＝-20.549,P＜0.01)、转复累积能量(β＝0.004,P＜0.05)是左心耳顿抑的独立危险因素.结论房颤持续时间、左心房内径、左心室射血分数和累积复律能量是房颤电转复后左心耳顿抑的独立预测因子.     

Initial worldwide experience with the WATCHMAN left atrial appendage system for stroke prevention in atrial fibrillation.

OBJECTIVES: This study assessed the feasibility of implanting a device in the left atrial appendage (LAA) in patients with atrial fibrillation (AF) to prevent thromboembolic stroke. BACKGROUND: Meta-analyses confirmed that in cases of left atrial thrombus in nonrheumatic AF patients approximately 90% of them are in the LAA. METHODS: The WATCHMAN Left Atrial Appendage System (Atritech Inc., Plymouth, Minnesota) is a nitinol device implanted percutaneously to seal the LAA. Patients were followed by clinical and transesophageal echocardiography at 45 days and 6 months with annual clinical follow-up thereafter. RESULTS: Sixty-six patients underwent device implantation. Mean follow-up was 740 +/- 341 days. At 45 days, 93% (54 of 58) devices showed successful sealing of LAA according to protocol. Two patients experienced device embolization, both successfully retrieved percutaneously. No embolizations occurred in 53 patients enrolled after modification of fixation barbs. There were 2 cardiac tamponades, 1 air embolism, and 1 delivery wire fracture (first generation) with surgical explantation but no long-term sequelae for the patient. Four patients developed a flat thrombus layer on the device at 6 months that resolved with additional anticoagulation. Two patients experienced transient ischemic attack, 1 without visible thrombus. There were 2 deaths, neither device related. Autopsy documented a stable, fully endothelialized device 9 months after implantation. No strokes occurred during follow-up despite >90% of patients with discontinuation of anticoagulation. CONCLUSIONS: Preliminary data suggest LAA occlusion with the WATCHMAN System to be safe and feasible. A randomized study is ongoing comparing oral anticoagulation with percutaneous closure.     

A new left atrial appendage occluder (Lifetech LAmbreTM Device) for stroke prevention in atrial fibrillation

Non-valvular atrial fibrillation (AF) is the commonest cardiac arrhythmia which causes ischemic stroke. Percutaneous left atrial appendage (LAA) closure is increasingly performed in AF patients with high stroke and bleeding risks. WATCHMAN and Amplatzer Cardiac Plug are the two mostly implanted devices worldwide with good clinical results. However, the need for relatively large delivery sheaths (9–14 French) and limited recapture and repositioning capabilities remains problematic for both devices. LAmbre? is a new; self-expanding LAA occluder constructed from a nitinol mesh and polyester membranes. It consists of an umbrella and a cover connected by a short central waist. The device is delivered by an 8-10 French sheath and has full recapture and repositioning capabilities. This report discussed in detail the novel features andprocedural steps for LAmbre? device.     

ECG-gated dual-source CT for detection of left atrial appendage thrombus in patients undergoing catheter ablation for atrial fibrillation

Purpose  

Left atrial ablation is increasingly used to treat patients with symptomatic atrial fibrillation (AF). Prior to ablation, exclusion of left atrial appendage (LAA) thrombus is important. Whether ECG-gated dual-source computed tomography (DSCT) provides a sensitive means of detecting LAA thrombus in patients undergoing percutaneous AF ablation is unknown. Thus, we sought to determine the utility of ECG-gated DSCT in detecting LAA thrombus in patients with AF.     

Left atrial appendage occlusion for stroke prevention in patients with atrial fibrillation

Atrial fibrillation (AF) is a commonly sustained atrial arrhythmia with associated morbidity and mortality. AF is associated with increased risk of thromboembolism and stroke, requiring use of anticoagulation. Anticoagulation decreases the risk of stroke but is associated with a higher risk of bleeding, necessitating discontinuation in some patients. The left atrial appendage is the likely source of thrombus in the majority of patients with AF. This has led to the development of left atrial appendage occlusion as a means to reduce stroke risk in patients who have a contraindication to long‐term anticoagulation. Multiple implantable devices have surfaced in the last few years, with some promising prospects. The main purpose of this review is to highlight the indications and use of these devices for left atrial appendage occlusion.     

Prediction of left atrial appendage thrombi in non-valvular atrial fibrillation.

AIMS: There is little knowledge about the predictors of left atrial appendage (LAA) thrombi in non-valvular atrial fibrillation (NVAF). We investigated the ability of D-dimer to predict LAA thrombi. METHODS AND RESULTS: In this study, 925 patients with NVAF were enrolled. At the time of transoesophageal echocardiography (TEE), D-dimer levels were measured simultaneously. Significant independent predictors of LAA thrombi were the presence of congestive heart failure [odds ratio (OR) 3.10, 95% confidence interval (CI) 1.77-5.50, P < 0.0001), a history of recent embolic events (OR 3.39, 95% CI 1.90-6.04, P < 0.0001), and D-dimer levels (OR 97.6, 95% CI 17.3-595.8, P < 0.0001). Receiver operating characteristic analysis yielded an optimal cutoff value of 1.15 microg/mL for D-dimer to detect LAA thrombi. LAA thrombi were detected in 21.8% of patients with higher D-dimer values, whereas it was detected in only 3.1% of patients with lower D-dimer values. D-dimer cutoff level of 1.15 microg/mL had a negative predictive value of 97% for identifying LAA thrombi. CONCLUSION: In patients with NVAF, D-dimer may be helpful for predicting the absence of LAA thrombi. D-dimer level was clinically useful to guide the management of patients with NVAF, especially for those complicated with congestive heart failure and/or recent embolic events.     

Disconnection of the left atrial appendage for elimination of foci maintaining atrial fibrillation

We report a case with paroxysmal atrial fibrillation, in whom multiple foci were identified in the left atrial appendage after pulmonary vein isolation. The patient was successfully treated by catheter ablation to disconnect this structure.