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A 41-year-old woman at 17 weeks gestation was referred for resting dyspnea. On physical examination, she had a faint diastolic murmur. ECG revealed mitral stenosis with dilated left atrium and a normal ejection fraction. She had two prior documented strokes and is noncompliant with her anticoagulant medication. She is not responding to the current medical management.
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Invisible left atrial thrombus
The patient was known to have rheumatic mitral stenosis since 1992. Her first two pregnancies were uneventful. Prior to this pregnancy, she was noncompliant with her anticoagulant medication and had two documented strokes.
A transthoracic echocardiogram (TTE) revealed severe mitral stenosis, depressed left ventricular ejection fraction, elevated filling pressures, and severe pulmonary hypertension. No intracardiac thrombus was detected. Due to a high index of suspicion for an intracardiac clot, a plan was made for her to have a transesophageal echocardiogram (TEE).
She underwent a 2D and 3D TEE to assess her mitral valve suitability for transcutaneous balloon valvuloplasty. Severe mitral stenosis with mean gradient of 12 mm Hg and a mitral valve area of 0.6 cm1 was noted (Fig 1). Also revealed was a large organized left atrial (LA) thrombus extending from the LA appendage to the LA anterolateral and posterior walls, with significant spontaneous echo contrast within the cavity (Fig 2).
Due to unfavorable prognosis of mitral stenosis with the symptom of severe dyspnea, the patient was advised to have the pregnancy terminated and opted to do so. A week after a successful and uncomplicated induction, she underwent surgical mitral valve replacement with a St. Jude mitral prosthesis (size 31 mm), thrombus evacuation, left atrial appendage ligation, and a maze procedure. At surgery, the presence of an LA thrombus in the anterolateral and posterior septal surfaces was confirmed. Her postoperative course was uneventful, and she was discharged receiving coumadin and with an international normalized ratio within therapeutic range.
At the time of open heart surgery, the TEE findings were confirmed. TTE, however, fails to identify LA thrombi in up to 50% of cases.1, 2, 3, 4 TEE, in contrast, provides higher resolution images of the LA appendage and body. It is more accurate in identifying, localizing, and quantifying LA thrombi. 3D TEE provides vivid details of complex spatial intracardiac anatomy, as noted in this case (Figs 3-5).
References
Bansal RC, Heywood JT, Applegate PM, et al. Detection of left atrial thrombi by two-dimensional echocardiography and surgical correlation in 148 patients with mitral valve disease. Am J Cardiol 1989; 15; 64:243-246
Okyay K, Cengel A, Tavil Y. Images in cardiology: a giant left atrium with two huge thrombi without embolic complications. Can J Cardiol 2007; 23:1088
Parekh A, Jaladi R, Sharma S, et al. Images in cardiovascular medicine: the case of a disappearing left atrial appendage thrombus--direct visualization of left atrial thrombus migration, captured by echocardiography, in a patient with atrial fibrillation, resulting in a stroke. Circulation 2006; 114:e513-e514
Agoston I, Xie T, Tiller FL, et al. Assessment of left atrial appendage by live three-dimensional echocardiography: early experience and comparison with transesophageal echocardiography. Echocardiography 2006; 23:127-132
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Contact information: jchiong@llu.edu
