Thromboembolism Risk in Patients with Mitral Stenosis.

Abstract

SUMMARYA total of 168 consecutive patients with predominant rheumatic mitral stenosis were evaluated by transthoracic (TTE) and transesophageal echocardiography (TEE). Of the 168 patients, 35 had previous embolic events (group I) and 133 had no emboli (group II). A total of 77 (45.8%) patients had atrial fibrillation. The frequency of atrial fibrillation was higher in group I than group II (68.6% vs 39.8%, p<0.001). The incidence of left atrial enlargement was greater in group I (p<0.001). Mitral valve area was found to be smaller in group I compared to group II (p<0.001). In group I 83.3% and 29.2% of the patients with atrial fibrillation had left atrial spontaneous echo contrast (SEC) and left atrial thrombus, respectively, and 72.7% of the patients with sinus rhythm had left atrial SEC. In group II 79.2% and 20.8% of the patients with atrial fibrillation had left atrial SEC and left atrial thrombus whereas 28.6% and 2.6% of the patients with sinus rhythm had left atrial SEC and left atrial thrombus, respectively. The incidence of left atrial thrombus was significantly different in those patients with compared to those without embolic events (20% vs 9.7%, p<0.01). In groups I and II, 28 of 35 (80%) and 64 of 133 (48.1%) patients had left atrial SEC (p<0.01). Patients with left atrial SEC had a greater left atrial size (p<0.01) and smaller mitral valve area (p<0.01). Left atrial size was normal in 2 patients with left atrial SEC and SEC was not found in 55 patients with enlarged left atrium. Multiple logistic regression analysis showed that atrial fibrillation, mitral valve area and left atrial enlargement were independent predictors of the SEC (p<0.001) and left atrial SEC was the principal determinant of thromboembolism.These data suggest that regardless of rhythm and atrial size, left atrial SEC is a principal determinant of thromboembolic risk in mitral stenosis. TEE may be able to detect those patients with mitral stenosis at risk for emboli and guide appropriate therapy. (Jpn Heart J 1997; 38: 669-675)

Annular Systolic Velocity Predicts the Presence of Spontaneous Echo Contrast in Mitral Stenosis Patients with Sinus Rhythm

“…4 The presence of SEC has been associated with thromboembolic risk and this risk increases with the density of SEC. 1,2,4,5,15 In our study, 47.4% of the patients with dense SEC had thromboembolism. Diagnosis of dense SEC and initiation of anticoagulant therapy are crucial for such patients.…”

The Factors Causing Left Atrial Appendage Clot Formation in Patients With Severe Rheumatic Mitral Stenosis

“…9 Left Atrial Appendage (LAA) is the common site for thrombus formation. 10 Increasing age and severity ofmitral stenosis (MS) also increase the risk of thrombus formation. 4,10 De-pressed LAA function has also shown to be one of the predictor of LAA clot formation.…”

“…10 Increasing age and severity ofmitral stenosis (MS) also increase the risk of thrombus formation. 4,10 De-pressed LAA function has also shown to be one of the predictor of LAA clot formation. 11 Left atrial thrombus can be defined as echo dense mass of any size with independent motion relative to chamber wall found in left atrial cavity or LAA.…”

Management of rheumatic atrial fibrillation

“…Other echocardiographic predictors of thromboemboli include the presence of spontaneous echo contrast and a reduced LAA emptying flow velocity. (18,19) In a recent prospective study of MS and sinus rhythm, transient subclinical AF detected by a single Holter monitor was detected in 27% of cases and was an independent predictor of systemic embolism with a crude embolic rate of 5.3% per year. (16) It is likely that subclinical AF is higher in clinical practice as monitoring for AF was limited to 24 hours in this study.…”