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Predictors of left atrial appendage clot: a transesophageal echocardiographic study of left atrial appendage function
Kewal C Goswami1, Rakesh Yadav, Vinay K Bahl
1Department of Cardiology, Cardiothoracic Sciences Centre, All India Institute of Medical Sciences, New Delhi.
Insights
Patients with severe mitral stenosis and reduced left atrial appendage function, even in normal sinus rhythm, face a higher risk of clot formation. Routine anticoagulation is recommended for those with left atrial appendage ejection fraction ≤25% to prevent clots.
Area of Science:
- Cardiology
- Echocardiography
- Thrombosis
Background:
- Severe rheumatic mitral stenosis poses risks for clot formation.
- Left atrial appendage (LAA) function is crucial in preventing thrombus.
- Understanding LAA function in non-anticoagulated patients is vital.
Purpose of the Study:
- To evaluate LAA function in non-anticoagulated patients with severe mitral stenosis.
- To analyze the relationship between LAA function, LAA clot, and spontaneous echo contrast.
- To identify predictors of LAA clot formation.
Main Methods:
- Prospective study of 200 consecutive patients with severe mitral stenosis.
- Transesophageal echocardiography to assess LAA function and flow patterns.
- Correlation analysis with LAA clot and spontaneous echo contrast.
Main Results:
- LAA clot found in 25% of patients; spontaneous echo contrast in 56.5%.
- Reduced LAA ejection fraction (≤25%) and atrial fibrillation were independent predictors of clot.
- Patients with clot or spontaneous echo contrast showed significantly impaired LAA filling and emptying velocities.
Conclusions:
- Depressed LAA function (LAA ejection fraction ≤25%), even in normal sinus rhythm, increases clot risk in mitral stenosis.
- Routine anticoagulation is advised for these high-risk patients to prevent LAA clot formation.
Background:
The purpose of this study was to prospectively evaluate a large group of consecutive, non-anticoagulated patients with severe rheumatic mitral stenosis and to analyze the left atrial appendage function in relation to left atrial appendage clot and spontaneous echo contrast formation.
Methods And Results:
We prospectively studied left atrial appendage function in 200 consecutive patients with severe mitral stenosis who underwent transesophageal echocardiography and correlated it with spontaneous echo contrast and left atrial appendage clot. The mean age was 30.2 +/- 9.4 years. Fifty-five (27.5%) patients were in atrial fibrillation. Left atrial appendage clot was present in 50 (25%) patients and 113 (56.5%) had spontaneous echo contrast. The older age, increased duration of symptoms, atrial fibrillation, spontaneous echo contrast, larger left atrium, depressed left atrial appendage function and type II and III left atrial appendage flow patterns correlated significantly (p<0.05) with the left atrial appendage clot. Left atrial appendage ejection fraction was significantly less in patients with clot (21.8 +/- 12.8% v. 39.1 +/- 13.2%, p<0.0001) and in those with spontaneous echo contrast (30.3 +/- 16.2 % v. 40.3 +/- 11.8%, p<0.001). Left atrial appendage filling (18.0 +/- 11.7 v. 27.6 +/- 11.8 cm/s, p <0.0001) and emptying velocities (15.4 +/- 7.0 v. 21.5 +/- 9.6 cm/s, p<0.001) and filling (1.4 +/- 1.0 v. 2.5 +/- 1.4 cm, p<0.0001) and emptying (1.5 +/- 1.2 v. 2.1 +/- 1.2 cm, p <0.05) velocity time integrals were also significantly lower in patients with clot as compared to those without clot. On multivariate regression analysis, atrial fibrillation (odds ratio 6.68, 95% CI 1.85-24.19, p=0.003) and left atrial appendage ejection fraction (odds ratio 1.06, 95% CI 1.00 - 1.11, p=0.04) were the only two independent predictors of clot formation. Incidence of clot was 62.59% in patients with left atrial appendage ejection fraction < or = 25% as compared to 10.4% in those having left atrial appendage ejection fraction >25%. Similarly patients with spontaneous echo contrasthadlower filling (21.7 +/- 11.5 v. 29.4 +/- 12.7 cm/s, p<0.0001) and emptying (17.0 +/- 8.1 v. 23.9 +/- 10.9 cm/s, p<0.0001) velocities, as well as filling (1.9 +/- 1.3 v. 2.7 +/- 1.3 cm, p<0.01) and emptying (1.7 +/- 1.0 v. 2.3 +/- 1.4 cm, p<0.01) velocity time integrals as compared to patients without spontaneous echo contrast. In a subgroup of the patients with normal sinus rhythm, the left atrial appendage ejection fraction was significantly less in patients with clot compared to those without clot (31.2 +/- 13.2 v. 41.3 +/- 11.5 %, p<0.01).
Conclusions:
In the patients with severe mitral stenosis, besides atrial fibrillation, a subgroup of patients in normal sinus rhythm with depressed left atrial appendage function (left atrial appendage ejection fraction < or = 25%) had a higher risk of clot formation in left atrial appendage and these patients should be routinely anticoagulated for prevention of clot formation.
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