TEE-Guided Versus CCTA-Guided Preprocedural Imaging for Left Atrial Appendage Closure

Eligible participants will be adults with nonvalvular atrial fibrillation for whom LAAC is planned for stroke prevention. After written informed consent and confirmation of eligibility, participants will be randomized in a 1:1 ratio through a centralized electronic system using center-stratified, variable-block randomization.

In the TEE-guided group, preprocedural planning will be based primarily on TEE measurements of left atrial appendage morphology, ostial dimensions, depth, and adjacent structures. In the CCTA-guided group, planning will be based primarily on CCTA assessment of morphology, three-dimensional anatomy, ostial area, depth, and adjacent structures. In both groups, the assigned modality will guide occluder type and size selection. Use of the nonassigned modality when clinically necessary will be documented. The indication for LAAC, the procedure itself, intraprocedural imaging, and postprocedural management will follow standardized routine care.

The trial has two linked components. The randomized strategy comparison evaluates procedural performance and early clinical safety. An embedded paired-imaging study will compare TEE and CCTA within the same participant at 3 months after LAAC. Clinical events will be adjudicated by an independent clinical event committee blinded to randomized assignment. Prespecified imaging outcomes will be assessed by a blinded imaging core laboratory. Follow-up visits are planned before discharge and at 3, 6, and 12 months after LAAC.

Inclusion criteria

• 1. Age 18 years or older. 2. Diagnosis of nonvalvular atrial fibrillation, including paroxysmal, persistent, or permanent atrial fibrillation.

• Planned percutaneous left atrial appendage closure for stroke prevention and considered by the investigator to meet an accepted indication for LAAC.

• Able to complete randomization and the assigned preprocedural imaging assessment.

• Expected to be able to complete paired TEE and CCTA follow-up at 3 months after LAAC.

• Able to complete protocol-specified clinical follow-up. 7. Written informed consent provided by the participant.

Exclusion criteria

• 1. Atrial fibrillation with moderate or severe mitral stenosis or a history of mechanical valve replacement.

• Contraindication to TEE, such as severe esophageal disease or inability to tolerate the procedure.

• Contraindication to CCTA, such as severe renal dysfunction or a known allergy to iodinated contrast that cannot be adequately premedicated.

• Another established indication for long-term full-dose anticoagulation, such as a mechanical valve or active venous thromboembolism.

• Life expectancy shorter than 1 year or a severe noncardiovascular disease that may prevent completion of follow-up or reliable assessment of clinical events.

• Pregnancy or breastfeeding. 7. Any other condition that, in the investigator's judgment, makes participation inappropriate.