Real time 3-dimensional transesophageal echocardiography is more specific than 2-dimensional TEE in the assessment of left atrial appendage thrombosis

Preprocedural Planning of Left Atrial Appendage Occlusion: A Review of the Use of Additive Manufacturing

Stroke is a significant public health problem, with non-valvular atrial fibrillation (NVAF) being one of its main causes. This cardiovascular arrhythmia predisposes to the production of intracardiac thrombi, mostly formed in the left atrial appendage (LAA). When there are contraindications to treatment with oral anticoagulants, another therapeutic option to reduce the possibility of thrombus formation in the LAA is the implantation of an occlusion device by cardiac catheterization. The effectiveness of LAA occlusion is dependent on accurate preprocedural device sizing and proper device positioning at the LAA ostium, to ensure sufficient device anchoring and avoid peri-device leaks. Additive manufacturing, commonly known as three-dimensional printing (3DP), of LAA models is beginning to emerge in the scientific literature to address these challenges through procedural simulation. This review aims at clarifying the impact of 3DP on preprocedural planning of LAA occlusion, specifically in the training of cardiac surgeons and in the assessment of the perfect adjustment between the LAA and the biomedical implant.

Periprocedural Imaging for Left Atrial Appendage Closure: Computed Tomography, Transesophageal Echocardiography, and Intracardiac Echocardiography

Percutaneous left atrial appendage closure is increasingly performed for stroke prevention for patients with nonvalvular atrial fibrillation with contraindications to oral anticoagulation. The success and complication rates with left atrial appendage closure have dramatically improved with maturing experience, growing procedural familiarity, and preprocedural planning. Multimodality imaging involving cardiac computer tomography angiography, transesophageal echocardiography, or intracardiac echocardiography in conjunction with fluoroscopy has improved the efficacy, procedural success, and safety of left atrial appendage closure in recent years. Proceduralists need to familiarize themselves with the various modalities and understand their complimentary roles and their limitations.

Transesophageal echocardiography for the assessment of left atrial appendage thrombus: Study of the additional value of systematic real time 3D imaging after regular 2D evaluation

BACKGROUND

Two-dimensional transesophageal echocardiography (2DTEE) is currently validated for left atrial appendage (LAA) thrombus assessment but has some limitations.

AIMS

To evaluate the performance and interest of systematic real time three-dimensional transesophageal echocardiography (3DTEE) for LAA thrombus assessment, when performed after 2DTEE.

METHODS AND RESULTS

Consecutive patients undergoing TEE were prospectively included. LAA was first evaluated using 2DTEE, and patients were classified as "2D-NT" if no thrombus was found, "2D-T" in case of clear thrombus, or "2D-EQ" if equivocal. Then, 3DTEE of the LAA was performed and patients were similarly classified as "3D-NT," "3D-T," or "3D-EQ." Additional LAA CT scan was only performed if LAA thrombus was not clearly ruled out or confirmed by TEE. Additional value of 3DTEE after 2DTEE LAA evaluation was then assessed. We included 104 patients undergoing TEE. Agreement between 2DTEE and 3DTEE was very good for thrombus diagnosis (k = 0.936), but moderate for vacant LAA (k = 0.562) due to more frequent 2D-EQ than 3D-EQ (11.5% vs 2.9%; P = .016). 3DTEE allowed to refine the LAA status in 11 of 12 (91.7%) 2D-EQ patients: 10 3D-NT, 1 3D-T, and 1 3D-EQ. Coupling 3DTEE to 2DTEE permitted a definite LAA diagnosis in 103 of 104 (99%) vs 92 of 104 (88.5%) patients when 2DTEE was used alone (P = .002). Nine (8.7%) LAA thrombi were diagnosed, and 3 CT scan were performed.

CONCLUSION

3DTEE of the LAA is more effective for thrombus assessment than 2DTEE. 3DTEE should be particularly considered in case of equivocal 2DTEE, as it allows to reach a definite LAA diagnosis in almost all of the patients.

Percutaneous interventions for left atrial appendage exclusion: options, assessment, and imaging using 2D and 3D echocardiography

Percutaneous left atrial appendage (LAA) exclusion is an evolving treatment to prevent embolic events in patients with nonvalvular atrial fibrillation. In the past few years multiple percutaneous devices have been developed to exclude the LAA from the body of the left atrium and thus from the systemic circulation. Two- and 3-dimensional transesophageal echocardiography (TEE) is used to assess the LAA anatomy and its suitability for percutaneous closure to select the type and size of the closure device and to guide the device implantation procedure in conjunction with fluoroscopy. In addition, 2- and 3-dimensional TEE is also used to assess the effectiveness of device implantation acutely and on subsequent follow-up examination. Knowledge of the implantation options that are currently available along with their specific characteristics is essential for choosing the appropriate device for a given patient with a specific LAA anatomy. We present the currently available LAA exclusion devices and the echocardiographic imaging approaches for evaluation of the LAA before, during, and after LAA occlusion.

The left atrial appendage: anatomy, function, and noninvasive evaluation

The left atrial appendage (LAA) is a finger-like extension originating from the main body of the left atrium. Atrial fibrillation (AF) is the most common clinically important cardiac arrhythmia, occurring in approximately 0.4% to 1% of the general population and increasing with age to >8% in those >80 years of age. In the presence of AF thrombus, formation often occurs within the LAA because of reduced contractility and stasis; thus, attention should be given to the LAA when evaluating and assessing patients with AF to determine the risk for cardioembolic complications. It is clinically important to understand LAA anatomy and function. It is also critical to choose the optimal imaging techniques to identify or exclude LAA thrombi in the setting of AF, before cardioversion, and with current and emerging transcatheter therapies, which include mitral balloon valvuloplasty, pulmonary vein isolation, MitraClip (Abbott Laboratories, Abbott Park, Illinois) valve repair, and the implantation of LAA occlusion and exclusion devices. In this review, we present the current data regarding LAA anatomy, LAA function, and LAA imaging using the currently available noninvasive imaging modalities.

Transcatheter left atrial appendage occlusion

Occlusion of the left atrial appendage (LAA) may reduce the risk of stroke in patients with atrial fibrillation (AF). Trials comparing LAA occlusion to warfarin anticoagulation in patients with nonvalvular AF showed a reduction in hemorrhagic stroke, although an increase in safety events due to procedural complications. Long-term follow-up suggests possible superiority of LAA occlusion due to fewer strokes and bleeding events. The superior dosing and safety profiles of the novel oral anticoagulants raise the accepted threshold for safety and efficacy of LAA occlusion procedures, and underscore the need for randomized studies comparing LAA occlusion with these newer anticoagulants.