Left Atrial Appendage Morphology and Correlation With Stroke: A Narrative and Three-Dimensional Transesophageal...

The left atrial appendage (LAA) is the predominant site of thrombus formation in patients with non-valvular atrial fibrillation (AF). Accurate evaluation of LAA anatomy is therefore essential for both stroke risk stratification and procedural planning in LAA occlusion (LAAO). Although clinical scores such as CHA₂DS₂-VA guide anticoagulation strategies, they do not fully capture individual thromboembolic risk. Growing evidence indicates that LAA morphology and geometry provide incremental prognostic information beyond traditional clinical factors. Multiple studies have consistently demonstrated a lower stroke risk associated with the chicken wing (CW) morphology, whereas cauliflower, cactus, and windsock configurations are linked to higher thromboembolic risk. More recent investigations suggest that specific anatomical features-such as bend angle, ostium-to-bend distance, ostial shape, and LAA volume-may be stronger determinants of blood stasis and thrombogenesis than qualitative shape classification alone, with improved reproducibility. Most data on LAA morphology derive from cardiac computed tomography or magnetic resonance imaging. However, advances in three-dimensional transesophageal echocardiography (3D TEE), including en face visualization, multiplanar reconstruction, and glass rendering, now enable detailed, real-time, radiation-free assessment of LAA anatomy. This review summarizes current evidence linking LAA morphology to thromboembolic risk and provides a practical overview of advanced 3D TEE techniques for comprehensive LAA evaluation, with step-by-step guidance approach. The LAA is the primary site of thrombus formation in AF, and the chicken-wing morphology is associated with a lower risk of ischemic stroke compared with non-chicken-wing types. Advanced 3D TEE assessment is crucial for detailed morphological evaluation and for planning LAAO procedures. This review outlines how to evaluate the LAA using advanced 3D TEE techniques.