Which left atrial appendage shape has the lowest risk of thromboembolism?

• A. Windsock
• B. Cauliflower
• C. Cactus
• D. Chicken wing

Answer: (D)

The left atrial appendage shape affects how blood flows within it, which in turn influences the likelihood of clot formation in atrial fibrillation. The chicken wing morphology, with a sharp bend in the dominant lobe, tends to promote more organized and faster flow and reduces stagnant pockets. This favorable flow pattern means clots are less likely to form, so thromboembolism risk is lower compared with the other shapes.

In contrast, windsock, cauliflower, and cactus shapes create more complex and irregular cavities with potential areas of low velocity and stasis, which are more prone to thrombus formation and thus higher thromboembolism risk.