In patients with mitral stenosis, thrombus formation is most commonly found in which locations?

• A. Left atrium and left atrial appendage
• B. Left ventricle
• C. Right atrium
• D. Pulmonary veins

Answer: (A)

Mitral stenosis causes obstruction of flow into the left ventricle, which raises left atrial pressure and leads to dilation and sluggish, pooling blood in the left atrium. The left atrial appendage is a particular site where blood can become stagnant due to its shape and limited flow, making it a prime location for thrombus formation. Atrial fibrillation, which is common in mitral stenosis, further reduces atrial contraction and enhances stasis, increasing the risk of clotting in the left atrium and its appendage. Because of these factors, thrombi most often form in the left atrium and left atrial appendage, rather than in the left ventricle, right atrium, or pulmonary veins.