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.     

Surgical clip closure of the left atrial appendage

Atrial fibrillation (AF) is the most common atrial arrhythmia, but it is not a benign disease. AF is an important risk factor for thromboembolic events, causing significant morbidity and mortality. The left atrial appendage (LAA) plays an important role in thrombus formation, but the ideal management of the LAA remains a topic of debate. The increasing popularity of surgical epicardial ablation and hybrid endoepicardial ablation approaches, especially in patients with a more advanced diseased substrate, has increased interest in epicardial LAA management. Minimally invasive treatment options for the LAA offer a unique opportunity to close the LAA with a clip device. This review highlights morphologic, electrophysiologic, and surgical aspects of the LAA with regard to AF surgery, and aims to illustrate the importance of surgical clip closure of the LAA.     

Morphological changes of the left atrial appendage after catheter ablation of atrial fibrillation

Introduction: The left atrial appendage (LAA) has been proven to be the most important site of thrombus formation in patients with atrial fibrillation (AF). However, the information regarding the morphometric alteration of the LAA related to the outcome of AF ablation is still lacking. Thus, we evaluated the long-term changes of the LAA morphology in patients undergoing catheter ablation of AF using magnetic resonance angiography (MRA).
Methods and Results: Group 1 included 15 controls without any AF history. Group 2 included 40 patients with drug-refractory paroxysmal AF. They were divided into two subgroups: group 2a included 30 patients without AF recurrence after pulmonary vein (PV) ablation. Group 2b included 10 patients with late recurrence of AF. The LAA morphology before and after (20 ± 11 months) ablation was evaluated by three-dimensional MRA. The group 2 patients had a larger baseline LAA size (including the LAA orifice, neck, and length) and less eccentric LAA orifice and neck. After the AF ablation, there was a significant reduction in the LAA size in the group 2a patients, and the morphology of the LAA neck became more eccentric during the follow-up period. In group 2b, the LAA size increased and no significant change in the eccentricity of the orifice and neck could be noted.
Conclusions: The morphometric remodeling of the LAA in the AF patients could be reversed after a successful ablation of the AF. Progressive dilation of the LAA was noted in the patients with AF recurrence. These structural changes in the LAA may play a role in reducing the potential risk of cerebrovascular accidents.     

Serious complications from dislocation of a Watchman left atrial appendage occluder

Left atrial appendage (LAA) elimination is regarded to protect patients with atrial fibrillation (AF) from stroke or embolism. The Watchman occluder is a device for percutaneous LAA occlusion and is at present investigated in the PROTECT AF trial. In a 78-year-old man, embolization of the Watchman device occurred 10 minutes after implantation. At emergency cardiac surgery, the device was removed from the aortic valve and an aortic bioprosthesis and a pacemaker had to be implanted. One year postoperatively, he still suffers from heart failure. This case shows that percutaneous LAA occlusion may result in serious complications.     

Changes in fibrinolytic activity and coagulation factors after epicardial left atrial appendage closure in patients with atrial fibrillation

BackgroundThe left atrial appendage (LAA) is known to be the primary source of thrombus formation in atrial fibrillation (AF). We investigate whether epicardial LAA occlusion (LAAO) from the cardiovascular system has an effect on coagulation and prothrombotic status in AF.MethodsTwenty-two patients with nonvalvular AF, who were not currently receiving oral anticoagulation (OAC) therapy, participated in a single-center prospective study. We measured fibrinogen and plasminogen levels along with plasma fibrin clot permeability, clot lysis time (CLT) and endogenous thrombin potential (ETP) before the LAAO procedure, at discharge and 1 month afterward.ResultsOne month after the LAAO procedure, plasma fibrin clot permeability improved by 39.3% as measured by clots prepared from peripheral blood (P=0.019) and also after adjustment for fibrinogen (P=0.027). Higher plasma fibrin clot permeability was associated with improved clot susceptibility to lysis (r=−0.67, P=0.013). CLT was reduced by 10.3% (P=0.0020), plasminogen activator inhibitor-1 antigen levels were reduced by 52% (P=0.023) and plasminogen activity was increased by 8.9% (P=0.0077). A trend toward decreased thrombin generation, reflected by a decreased ETP and peak thrombin generated was also observed 1 month after LAAO procedure (P=0.072 and P=0.087, respectively). No differences were observed in tissue-type plasminogen activator and thrombin-activatable fibrinolysis inhibitor plasma levels (both P>0.05).ConclusionsObtained results seem to confirm that LAA plays a key role in thrombogenesis. Elimination of LAA from the circulatory system may improve fibrin clot permeability and susceptibility to fibrinolysis in peripheral blood.     

射频消融联合左心耳封堵术治疗心房纤颤17例回顾性分析

目的探讨心房颤动"一站式"手术的有效性和安全性。方法回顾性分析临床17例心房纤颤患者通过射频消融联合左心耳封堵"一站式"手术治疗后的临床资料。结果手术后出现肺部感染2例(11.76%),一过性交界性逸搏心律2例(11.76%),食管瘘1例(5.89%),术后3个月经食道超声心动图复查发现,封堵器表面血栓形成1例(5.89%),术后6个月随访无卒中、出血及死亡患者,1例患者心房颤动复发,继续抗凝治疗,其他患者均改为阿司匹林或氯吡格雷单联抗栓治疗。结论对于卒中高危且有抗凝禁忌的非瓣膜性心房颤动患者,射频消融联合左心耳封堵"一站式"手术是可行的、安全的、有效的。     

左心耳电隔离在持续性心房颤动治疗中的研究进展

肺静脉隔离是心房颤动(房颤)导管消融的基石,对于阵发性房颤有良好效果,但在持续性房颤中的效果则不尽人意.肺静脉隔离以外的辅助消融策略有助于提高持续性房颤的手术成功率.左心耳不仅是心腔内血栓的常见起源,还是导致快速性房性心律失常发生或维持的因素,因而左心耳电隔离成为持续性房颤辅助消融策略之一,研究表明其可能有助于提高持续...     

Role for the left atrial appendage occlusion device in managing thromboembolic risk in atrial fibrillation

Only 50% of patients who would benefit from warfarin therapy for atrial fibrillation (AF) receive treatment because of clinical concerns regarding chronic anti-coagulation. Percutaneous strategies to treat AF, including pulmonary vein isolation with a curative intent or atrioventricular nodal ablation and implantation of a permanent pacemaker for palliative rate control, have not eliminated the need to manage thromboembolic risk. With the development of a percutaneous left atrial appendage (LAA) occlusion device (the WATCHMAN percutaneous left atrial appendage occluder - Atritech Inc., Plymouth, MN, USA) for thromboembolic protection in non-valvular AF a significant therapeutic option for select patients may be available. We present the first case performed in Australia (24 November 2009) and explore this new methodology.     

Transcatheter left atrial appendage occlusion with Amplatzer devices to obviate anticoagulation in patients with atrial fibrillation.

It is assumed that over 90% of clinically apparent embolisms in atrial fibrillation originate from the left atrial appendage. Recently, a percutaneous method (PLAATO technique) to occlude the left atrial appendage to the end of preventing thromboembolic complications of atrial fibrillation has been introduced into clinical practice. This technique is quite intricate and requires general anesthesia. The Amplatzer atrial septal occluder lends itself for a more simple approach to this intervention. The first 16 patients treated at four centers are described. Their age varied from 58 to 83 years. All suffered from atrial fibrillation but eight of them were in sinus rhythm at the time of implantation. All but two procedures were done under local anesthesia of the groin only. There was one technical failure (device embolization) requiring surgery. All other patients left the hospital a day after the procedure without complications. There were no problems or embolic events during an overall follow-up of 5 patient-years and all left atrial appendages were completely occluded without evidence of thrombosis at the atrial side of the device at the latest follow-up echocardiography. With the Amplatzer technique, the left atrial appendage can be percutaneously occluded with a venous puncture under local anesthesia, without echocardiographic guidance, and at a reasonable risk. It remains to be evaluated in larger series or randomized trials how the simpler Amplatzer technique compares with the complex PLAATO technique, and whether left atrial appendage closure is competitive with oral anticoagulation with warfarin or the novel ximelagatran to prevent thromboembolism in atrial fibrillation.     

Comparison of multiple imaging modalities for measuring orifice diameter and selecting occluder size in patients undergoing left atrial appendage closure

BackgroundLeft atrial appendage (LAA) closure (LAAC) can safely and effectively prevent stroke events caused by atrial fibrillation. However, the structure of the LAA is highly variable among individuals, and the optimal method for obtaining measurements remains unknown.HypothesisWe aimed to study the accuracy of left atrial computed tomography angiography (CTA), three‐dimensional (3D) reconstruction using CTA, two‐dimensional transesophageal echocardiography (2D‐TEE), and digital subtraction angiography (DSA) for measuring the diameter of the LAA and compare their value for selecting occluder size.MethodsWe retrospectively evaluated data for 148 patients with nonvalvular atrial fibrillation who underwent successful LAAC. CTA and 2D‐TEE of the left atrium and pulmonary vein were performed before LAAC. We performed 3D reconstruction of the left atrium and LAA using Mimics and 3‐matics software. DSA of the LAA was performed during surgery.ResultsValues measured via CTA 3D reconstruction were significantly higher than those measured using other methods. DSA‐measured values were significantly lower than those measured via CTA and CTA 3D reconstruction. Occluder size was positively correlated with LAA orifice diameter. The differences between occluder size and DSA, 2D‐TEE, CTA, CTA 3D reconstruction measurements were 4.96 ± 2.58, 4.64 ± 2.50, 4.04 ± 1.37, and 2.92 ± 1.38 mm, respectively. Intraclass correlation coefficients for these methods were −.067, .006, .241, and .519, respectively.ConclusionCTA 3D reconstruction provides the best correlation and consistency between the measured LAA orifice diameter and occluder size. Adding 2–4 mm to the maximum LAA orifice diameter based on 3D‐CTA may aid in selecting the appropriate WATCHMAN device.