Clinical and Echocardiographic Parameters and Score for the Left Atrial Thrombus Formation Prediction in the Patients with Mitral Stenosis
Thananya Boonyasirinant MD*, Rewat Phankinthongkum MD*, Chulaluk Komoltri DrPH**
Affiliation : * Division of Cardiology, Department of Medicine, Department of Research Development, Faculty of Medicine, Siriraj Hospital, Bangkok **Division of Clinical Epidemiology, Department of Research Development, Faculty of Medicine, Siriraj Hospital, Bangkok
Background : Rheumatic mitral stenosis is one of the important health problems, especially in Thailand.
Thromboembolic complications from this disease remain the major problem in these patients. These complica-
tions are usually related to the left atrial thrombus formation.
Objective : To determine the parameters that can predict the presence of left atrial thrombus in these patients.
Materials and Methods : Two hundred and sixty Thai patients with mitral stenosis from Siriraj Hospital were
prospectively recruited in the study. The baseline clinical characteristics of these patients which were related
to thrombus formation were properly collected. All patients underwent the transthoracic and transesophageal
echocardiography with the standard technique to detect the mitral valve area, mitral valve score, left atrial
size, LV ejection fraction, right ventricular systolic pressure, spontaneous echo contrast (SEC) and associated
valvular lesions. Transesophageal echocardiography was used as the gold standard for evaluation of left
atrial thrombus. These parameters were analyzed to demonstrate association with the presence of left atrial
thrombus by univariate and multiple logistic regression analysis. Equation with score for prediction of left
atrial thrombus was also purposed.
Results : There were 77 men and 183 women in the present study. Left atrial thrombus was detected in 26% and
previous thromboembolic complications occurred in 16.5%. Atrial fibrillation presented in 52.5%. From
univariate analysis, atrial fibrillation (81.2% vs 42.9%, p < 0.001), male sex (37.7% vs 25.6%, p < 0.050), left
atrial enlargement by electrocardiogram (45.5% vs 15.4%, p < 0.001), left atrial diameter (7.26 vs 6.97 cm, p
< 0.030), left atrial volume (132.7 vs 113.5 cm2, p < 0.001), EF by Teich method (58.9 vs 62.5%, p < 0.011), EF
by MOD-bp (60.7 vs 64.6%, p < 0.005), tricuspid regurgitation (46.4% vs 28.8%, p < 0.008), mitral regurgi-
tation (10.1 vs 3.1%, p < 0.022), and RVSP (57.0 vs 49.7 mmHg, p < 0.005) can predict the presence of left
atrial thrombus formation with statistical significance. Using multiple logistic regression model, only atrial
fibrillation (OR 5.95, 95% CI 1.21-29.3, p < 0.02 ) and RVSP (OR 1.02, 95%CI 1.01-1.04, p < 0.04) were
independent predictors. The authors proposed score for predicting probability of left atrial thrombus forma-
tion that equal to -3.61 + 1.79 AF + 0.03 RVSP with AUC of 0.764. The best cut-off point for this score was -
1.49, which gave a sensitivity of 91%, specificity of 56%, PPV of 48%, and NPV of 90%.
Conclusion : Prevalence of thromboembolic complications and thrombus formation is high in patients with
mitral stenosis in Thailand. From the present study, the predictors for left atrial thrombus formation in the
patients with mitral stenosis were atrial fibrillation and RVSP. The model for predicting left trial thrombus
formation was also proposed with high sensitivity and NPV.
Keywords : Echocardiographic Parameters, Left Atrial Thrombus Formation, Predication, Mitral Stenosis
