Incidence and predictors of left atrial thrombus in patients with rheumatic mitral stenosis and sinus rhythm: a transesophageal echocardiographic study.

BACKGROUND

Rheumatic mitral stenosis (MS) predisposes to left atrial (LA) thrombus formation. The reported incidence of LA clot formation in sinus rhythm (SR) is 2.4-13.5% in small studies.

AIM: To determine the incidence of LA thrombus in MS in SR in a large cohort of patients and to determine the factors that predict its development.

METHODS

Total of 848 consecutive patients with MS in SR who were being evaluated for percutaneous transvenous mitral commisurotomy were included in the study. Both transthoracic (TTE) and transesophageal echocardiograms (TEE) were performed to identify clot and other hemodynamic parameters.

RESULTS

The mean age of the study population was 34 ± 9 years and the mean mitral orifice area was 0.78 ± 0.18 cm(2). Out of 848 patients 56 (6.6%) had LA thrombus on TEE. On univariate analysis there was a trend toward thrombus formation in individuals with age >44 years, LA inferosuperior dimension >6.9 cm, mean mitral gradient >18 mmHg and dense spontaneous echo contrast (SEC). On multivariate analysis none of the factors predicted clot formation.

CONCLUSION

The incidence of LA thrombus in MS in SR is 6.6%. TEE is warranted in MS patients in SR when they are >44 years, LA inferosuperior dimension >6.9 cm and mean mitral gradient >18 mmHg. When SEC is absent on TEE, thrombus formation is unlikely.