Spectrum of Left Atrium or Left Atrial Appendage Thrombus in Patients with Mitral Stenosis

Abstract

Objectives: The presence of thrombus in the left atrium (LA) or left atrial appendage (LAA) is a frequent contraindication for percutaneous mitral balloon valvotomy (PMBV). However, previous studies have indicated that PMBV may be feasible in selected thrombus types without increasing the risk of thromboembolic complications. This study aimed to classify LA/LAA thrombi based on their location and extension. Methodology: This study included 100 patients with rheumatic mitral stenosis (MS) and documented thrombus in the LA or LAA. All patients underwent transthoracic echocardiography (TTE), followed by transesophageal echocardiography (TEE) in cases where TTE did not reveal thrombus. Thrombi were categorized into seven types as described in previous literature: type Ia (confined to appendage), Ib (protruding into LA cavity), IIa (above the plane of fossa ovalis), IIb (below the plane of fossa ovalis), III (over the interatrial septum), IV (mobile clot attached to the LA free wall, roof, or interatrial septum), and V (free floating). Results: Of the 100 patients, 70% were female, with a mean age of 46.1 ± 12.2 years. Atrial fibrillation was present in 84% of cases. Thrombus was detected on TTE in 15% of patients, while 85% were diagnosed via TEE. The most common thrombus type was Ia (69%), followed by type Ib (21%), both of which are considered suitable for PMBV. The "chicken wing" morphology was the most prevalent LAA shape (46%), followed by the "windsock" (26%) and "cactus" (6%) shapes. Conclusion: Thrombus types Ia, Ib, and IIa were the most frequently observed and are considered feasible for PMBV. The chicken wing morphology was the most common LAA shape in this cohort. These findings may support the potential role of PMBV in selected patients with LA/LAA thrombi.