Clinical and Echocardiographic Predictors of Left Atrial Thrombus in Rheumatic Mitral Stenosis

Objectives: To evaluate various clinical and echocardiographic predictors of left atrial (LA) thrombus in patients with severe mitral stenosis and to determine the utility of transesophageal (TEE ) as compared to transthoracic echocardiography (TTE) in detection of thrombus in LA. Place and Duration of Study: Department of Echocardiography and Out Patient Department of Punjab Institute of Cardiology, Lahore from January 2007 to April 2007. Study Design: It was an observational analytical study. Patients and Methods: In this study left atrial (LA) thrombus and spontaneous echo contrast were evaluated by both TTE and subsequent TEE in 100 patients with rheumatic mitral stenosis. The study population was divided into two groups: Group I consisted of 38 (15.2%) patients having thrombus in LA and Group II consisting of 212 (84.8%) patients with no thrombus in LA. Various clinical and echocardiographic variables were compared in these two groups. Results: Two hundred and fifty consecutive patients having tight rheumatic mitral stenosis were studied. The mean age of the study population was 26.9 ± 7.5 years. There were more female 128 (51.2%) patients than males 122 (48.8%). Atrial fibrillation (AF) was present less frequently in the study as 33 (13.2%) patients had AF as compared to 217 (86.8%) patients having sinus rhythm. AF was more significantly associated with thrombus formation with 23 (60.5%) patients having thrombus as compared to 15 (39.5%) patients in sinus rhythm having thrombus p < 0.0001. Thrombus in LA was more commonly visualized on TEE as compared to TTE (X2=242.3, p=0.0001) and was mostly detected in left atrial appendage (X2=211.2, p=0.0001). Spontaneous echo contrast was visualized more frequently on TEE as compared to TTE in both the groups p<0.001. Conclusion: TEE is better than conventional TTE in detecting left atrial thrombi in patients with severe mitral stenosis having AF. Patients with rheumatic mitral stenosis having atrial fibrillation, large left atrial size and old age are more prone to have LA thrombus.