Transcatheter left atrial appendage closure for stroke prevention among atrial fibrillation patients

Left atrial appendage occlusion: A better alternative to anticoagulation?

Non-valvular atrial fibrillation is associated with a significantly increased risk of embolic stroke due to blood clot forming predominantly in the left atrial appendage (LAA). Preventive measures to avoid embolic events are permanent administration of anticoagulants or surgical closure of the LAA. Various clinical trials provide evidence about safety, effectiveness and therapeutic success of LAA occlusion using various cardiac occluder devices. The use of such implants for interventional closure of the LAA is likely to become a valuable alternative for stroke prevention, especially in patients with contraindication for oral anticoagulation as safety, clinical benefit and cost-effectiveness of LAA occlusion has recently been demonstrated.

Left Atrial Appendage Parameters Assessed by Real-Time Three-Dimensional Transesophageal Echocardiography Predict Thromboembolic Risk in Patients With Nonvalvular Atrial Fibrillation

OBJECTIVES

In nonvalvular atrial fibrillation (NVAF) patients, the effect of left atrial appendage (LAA) morphology, structure, and hemodynamic characteristics evaluated by real-time 3D transesophageal echocardiography (RT3D-TEE) on thromboembolic risk has not been elucidated.

METHODS

A total of 444 NVAF patients who underwent clinically indicated RT3D-TEE were enrolled in the study. The orifice size, orifice area, depth, and volume measurements of the LAA were assessed using Philips QLAB 9.0. The LAA characteristics were compared among different CHA₂ DS₂ -VASc thromboembolic risk subgroups, as well as between the thromboembolic event and nonevent groups.

RESULTS

The orifice size, orifice area, and end-diastolic volumes of the LAA were increased with an increasing CHA₂ DS₂ -VASc risk score in the NVAF patients, whereas the emptying rate was decreased. The NVAF patients with LAA thrombus exhibited a significantly increased end-diastolic volume (7.39 ± 3.47 versus 5.21 ± 2.59 mL, P = .003) and higher prevalence of the cauliflower shaped LAA (64.3% versus 25%, P = .004) compared with those without thrombus. Logistic regression indicated that the LAA end-diastolic volume (P = .002; odds ratio 1.556; 95% confidence interval 1.176-2.057) and cauliflower shape (P = .001; odds ratio, 10.177; 95% confidence interval, 2.458-42.140) were independent predictors of thromboembolic events in patients with NVAF following adjustment for the CHA₂ DS₂ -VASc score.

CONCLUSIONS

The LAA end-diastolic volume and cauliflower phenotype predict thromboembolic events independent of the CHA₂ DS₂ -VASc score, and these data improve stroke prediction in NVAF patients.

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.