CASE REPORTS
Embolization of a Left Atrial Ball Thrombus during Transesophageal Echocardiography Ian W. Black, MBBS, FRACP, Gregory B. Cranney, MBBS, FRACP, Warren F. Walsh, MBBS, FRACP, FACC, and David Brender, MD, FRACP, FACC, Sydney) Australia
We report a case of systemic embolization of a left atrial ball thrombus during transesophageal echocardiography (TEE). A 49-year-old man with rheumatic mitral stenosis and atrial fibrillation underwent TEE to evaluate a transient cerebral ischemic attack. TEE demonstrated a free-floating left atrial thrombus. Disappearance of the thrombus during the study occurred after tachycardia and was associated with acute hemiplegic stroke and an absent radial pulse. The possible mechanism of embolization and the implications for the selection and management of patients undergoing TEE are discussed. (JAM Soc EcHOCARDIOGR 1992;5:271-3.)
Transesophageal echocardiography (TEE) provides
high-resolution, dose-range imaging of the left atrial cavity and appendage and is more sensitive than transthoracic echocardiography for detecing left atrial thrombil·2 and left atrial myxoma. 3 Complications of the technique have been rare. 4 We report a case of systemic embolization of a mobile left atrial thrombus during TEE. CASE HISTORY
A 49-year-old man with known rheumatic mitral stenosis presented with transient right hemiplegia and dysphasia. Warfarin (Coumadin) had been prescribed for the patient after he suffered a cerebrovascular accident with mild left hemiplegia at age 26 years, but he had not complied with the drug regimen and was not anticoagulated at the time of admission (prothrombin ratio 1.0). Physical examination revealed atrial fibrillation, accentuation of the first heart sound, no opening snap, and a rumbling middiastolic murmur at the apex that did not vary in intensity. There were no carotid bruits and the peripheral pulses were normal. Cerebral computed tomography showed right parietal infarction. Intravenous heparin and digoxin were commenced and the patient was From the Department of Cardiovascular Medicine, The Prince Henry Hospital. Reprint requests: Dr. W.F. Walsh, Department of Cardiovascular Medicine, The Prince Henry Hospital, Anzac Parade Little Bay, NSW 2036, Australia. 27/l/37220
referred for TEE to determine the presence of left atrial thrombi. Transthoracic two-dimensional and Doppler echocardiography performed immediately before TEE showed severe mitral stenosis (mitral valve area 0.7 cm2 ) and a severely dilated left atrium (M-mode dimension, 85 mm) that contained a 3 em-diameter mass freely mobile within the atrial cavity. TEE was done to define any attachment of the mass to the left atrial wall and to exclude left atrial appendage thrombi. After the patient was sedated with intravenous midazolam and fentanyl and lidocaine was applied for pharyngeal anesthesia, a 5 MHz biplane TEE transducer (HP 21363A, Hewlett Packard, Andover, Massachusetts) was inserted without difficulty. The left atrial mass was seen to consist of an internal echo-dense core with a less dense surface layer, consistent with laminated thrombus. No attachment of the thombus to the atrial wall could be detected. At times the thrombus rested transiently against the mitral valve orifice in diastole, appearing to occlude the orifice (Figure 1), before careening off during systole with a ping-pong ball appearance. Left atrial spontaneous echo contrast was present, and the left atrial appendage was free of thrombus. Several minutes after the commencement of the study the patient became restless and tachycardia developed (atrial fibrillation with ventricular rate 130/min), and he required further sedation. Pulse oximetry did not reveal hypoxia, and the appearance of the thrombus was unchanged. Two minutes later the patient's level of consciousness became depressed and he was found to have left hemiplegia and an absent right radial pulse. The previously noted 271
272 Black et al.
Journal of the American Society of Echocardiography
Figure 1 Transesophageal echocardiographic four-chamber view showing the laminated thrombus in the left atrium (LA). LV, Left ventricle; RA, right atrium; SEC, spontaneous echo contrast.
thrombus could no longer be visualized except for a 0.5-cm diameter mobile remnant that was observed transiently. The mitral valve orifice was not being imaged at the presumed time of embolization. An urgent cerebral computed tomogram was unchanged from the previous scan. Intravenous heparin was continued, and the right radial pulse returned several hours later. There was little improvement in the left hemiplegia and left-sided sensory deficit. After a repeat TEE confirming the absence of residual thrombus, the patient subsequently underwent successful percutaneous mitral valvuloplasty with an increase in mitral valve area to 2.1 cm2 • DISCUSSION
Free-floating thrombus within the left atrium, known as left atrial ball thrombus, is a rare complication of rheumatic mitral stenosis. Previous studies, recently reviewed by Wrisley et al., 5 have highlighted the importance of accurate diagnosis and prompt surgical removal of such thrombi because of the frequent and unpredictable occurrence of systemic embolism or sudden death caused by mitral valve occlusion.
The present patient was referred for TEE to evaluate suspected left atrial thrombus as the cause of a cerebral embolic episode. Although transthoracic echocardiography demonstrated a mobile atrial mass, TEE was able to define the internal characteristics of the thrombus, exclude other thrombi, and confirm the lack of attachment to the atrial wall. However, cerebral and limb embolism occurred during the procedure and were associated with disappearance of the thrombus. Although the occurrence of embolism may have been coincidental, the mechanisms by which TEE may have precipitated this event should be considered. Sherman et al. 6 postulated that embolization of free-floating left atrial thrombi might result from detachment of the entire thrombus, fragmentation of the thrombus as it is traumatized by the mitral valve in systole, or embolization of a second atrial thrombus. The actual moment of embolism of left atrial thrombus was not visualized in the present case and has not been visualized in any previous report. Embolization in the present case occurred several minutes after the onset of tachycardia associated with restlessness. Embolization to both the right brachial and right carotid arteries may have resulted from
Volume 5 Number 3 May-June 1992
fragmentation of the thrombus in the braciocephalic artery. However, the transient presence of a thrombus remnant and the large size of the thrombus compared with the mitral orifice imply that the thrombus became fragmented before or during passage through the mitral valve. Tachycardia may have elevated the transmittal gradiene and increased the frequency and force of thrombus collision with the mitral valve, resulting in passage of the thrombus through the mitral orifice. However, tachycardia as a consequence of an otherwise occult initial embolism cannot be excluded. There are no previous reports of embolism during TEE_ However, a recent report of rupture of an aortic dissection associated with retching during TEE 8 highlights the potential danger of hemodynamic and mechanical changes during the procedure. The present case may also be relevant to cases of mobile left atrial myxoma, in which tachycardia during TEE may increase the likelihood of fragmentation and subsequent embolization. This case illustrates the potential risk of TEE in patients with mobile left atrial masses and should be performed only if transthoracic echocardiography is nondiagnostic. IfTEE is considered necessary, maximum effort must be made to maintain hemodynamic stability during the procedure.
Embolization of LA thrombus during TEE 273
REFERENCES l. Bleifeld W. Transesophageal two-dimensional echocardiography for the detection of left atrial appendage thrombus. J Am
Coli Cardiol1986;7:163-6. 2. Acar J, Cormier B, Grimberg D, et a!. Diagnosis of left atrial thrombi in mitral stenosis-usefulness of ultrasound techniques compared with other methods. Eur Heart J 1991;12(suppl B):70-6. 3. Obeid Al, Marvasti M, Parker F, Rosenberg J. Comparison of transthoracic and transesophageal echocardiography in diagnosis of left atrial myxoma. Am J Cardiol 1989;63: 1006-8. 4. Daniel WG, Erbel R, Kasper W, eta!. Safety of transesophageal echocardiography. A multicenter survey of 10,419 examinations. Circulation 1991;83:817-21. 5. Wrisley D, Giambartolomei A, Lee I, Brownlee W. Left atrial ball thrombus: review of clinical and echocardiographic manifestations with suggestions for management. Am Heart J 1991;121:1784-90. 6. Sherman W, Nozad SE, Stoian A, Madias JE. Free-floating left atrial thrombus and systemic embolization. Chest 1985;87:694-5. 7. Arani DT, Carleton RA. The deleterious role of tachycardia in mitral stenosis. Circulation 1967;36:511-6. 8. Silvey SV, Stoughton TL, Pearl W, Collazo WA, Belbel RJ. Ruprure of the outer partition of aortic dissection during transesophageal echocardiography. Am J Cardiol 1991;68: 286-7.
Embolization of a Left Atrial Ball Thrombus during Transesophageal Echocardiography Ian W. Black, MBBS, FRACP, Gregory B. Cranney, MBBS, FRACP, Warren F. Walsh, MBBS, FRACP, FACC, and David Brender, MD, FRACP, FACC, Sydney) Australia
We report a case of systemic embolization of a left atrial ball thrombus during transesophageal echocardiography (TEE). A 49-year-old man with rheumatic mitral stenosis and atrial fibrillation underwent TEE to evaluate a transient cerebral ischemic attack. TEE demonstrated a free-floating left atrial thrombus. Disappearance of the thrombus during the study occurred after tachycardia and was associated with acute hemiplegic stroke and an absent radial pulse. The possible mechanism of embolization and the implications for the selection and management of patients undergoing TEE are discussed. (JAM Soc EcHOCARDIOGR 1992;5:271-3.)
Transesophageal echocardiography (TEE) provides
high-resolution, dose-range imaging of the left atrial cavity and appendage and is more sensitive than transthoracic echocardiography for detecing left atrial thrombil·2 and left atrial myxoma. 3 Complications of the technique have been rare. 4 We report a case of systemic embolization of a mobile left atrial thrombus during TEE. CASE HISTORY
A 49-year-old man with known rheumatic mitral stenosis presented with transient right hemiplegia and dysphasia. Warfarin (Coumadin) had been prescribed for the patient after he suffered a cerebrovascular accident with mild left hemiplegia at age 26 years, but he had not complied with the drug regimen and was not anticoagulated at the time of admission (prothrombin ratio 1.0). Physical examination revealed atrial fibrillation, accentuation of the first heart sound, no opening snap, and a rumbling middiastolic murmur at the apex that did not vary in intensity. There were no carotid bruits and the peripheral pulses were normal. Cerebral computed tomography showed right parietal infarction. Intravenous heparin and digoxin were commenced and the patient was From the Department of Cardiovascular Medicine, The Prince Henry Hospital. Reprint requests: Dr. W.F. Walsh, Department of Cardiovascular Medicine, The Prince Henry Hospital, Anzac Parade Little Bay, NSW 2036, Australia. 27/l/37220
referred for TEE to determine the presence of left atrial thrombi. Transthoracic two-dimensional and Doppler echocardiography performed immediately before TEE showed severe mitral stenosis (mitral valve area 0.7 cm2 ) and a severely dilated left atrium (M-mode dimension, 85 mm) that contained a 3 em-diameter mass freely mobile within the atrial cavity. TEE was done to define any attachment of the mass to the left atrial wall and to exclude left atrial appendage thrombi. After the patient was sedated with intravenous midazolam and fentanyl and lidocaine was applied for pharyngeal anesthesia, a 5 MHz biplane TEE transducer (HP 21363A, Hewlett Packard, Andover, Massachusetts) was inserted without difficulty. The left atrial mass was seen to consist of an internal echo-dense core with a less dense surface layer, consistent with laminated thrombus. No attachment of the thombus to the atrial wall could be detected. At times the thrombus rested transiently against the mitral valve orifice in diastole, appearing to occlude the orifice (Figure 1), before careening off during systole with a ping-pong ball appearance. Left atrial spontaneous echo contrast was present, and the left atrial appendage was free of thrombus. Several minutes after the commencement of the study the patient became restless and tachycardia developed (atrial fibrillation with ventricular rate 130/min), and he required further sedation. Pulse oximetry did not reveal hypoxia, and the appearance of the thrombus was unchanged. Two minutes later the patient's level of consciousness became depressed and he was found to have left hemiplegia and an absent right radial pulse. The previously noted 271
272 Black et al.
Journal of the American Society of Echocardiography
Figure 1 Transesophageal echocardiographic four-chamber view showing the laminated thrombus in the left atrium (LA). LV, Left ventricle; RA, right atrium; SEC, spontaneous echo contrast.
thrombus could no longer be visualized except for a 0.5-cm diameter mobile remnant that was observed transiently. The mitral valve orifice was not being imaged at the presumed time of embolization. An urgent cerebral computed tomogram was unchanged from the previous scan. Intravenous heparin was continued, and the right radial pulse returned several hours later. There was little improvement in the left hemiplegia and left-sided sensory deficit. After a repeat TEE confirming the absence of residual thrombus, the patient subsequently underwent successful percutaneous mitral valvuloplasty with an increase in mitral valve area to 2.1 cm2 • DISCUSSION
Free-floating thrombus within the left atrium, known as left atrial ball thrombus, is a rare complication of rheumatic mitral stenosis. Previous studies, recently reviewed by Wrisley et al., 5 have highlighted the importance of accurate diagnosis and prompt surgical removal of such thrombi because of the frequent and unpredictable occurrence of systemic embolism or sudden death caused by mitral valve occlusion.
The present patient was referred for TEE to evaluate suspected left atrial thrombus as the cause of a cerebral embolic episode. Although transthoracic echocardiography demonstrated a mobile atrial mass, TEE was able to define the internal characteristics of the thrombus, exclude other thrombi, and confirm the lack of attachment to the atrial wall. However, cerebral and limb embolism occurred during the procedure and were associated with disappearance of the thrombus. Although the occurrence of embolism may have been coincidental, the mechanisms by which TEE may have precipitated this event should be considered. Sherman et al. 6 postulated that embolization of free-floating left atrial thrombi might result from detachment of the entire thrombus, fragmentation of the thrombus as it is traumatized by the mitral valve in systole, or embolization of a second atrial thrombus. The actual moment of embolism of left atrial thrombus was not visualized in the present case and has not been visualized in any previous report. Embolization in the present case occurred several minutes after the onset of tachycardia associated with restlessness. Embolization to both the right brachial and right carotid arteries may have resulted from
Volume 5 Number 3 May-June 1992
fragmentation of the thrombus in the braciocephalic artery. However, the transient presence of a thrombus remnant and the large size of the thrombus compared with the mitral orifice imply that the thrombus became fragmented before or during passage through the mitral valve. Tachycardia may have elevated the transmittal gradiene and increased the frequency and force of thrombus collision with the mitral valve, resulting in passage of the thrombus through the mitral orifice. However, tachycardia as a consequence of an otherwise occult initial embolism cannot be excluded. There are no previous reports of embolism during TEE_ However, a recent report of rupture of an aortic dissection associated with retching during TEE 8 highlights the potential danger of hemodynamic and mechanical changes during the procedure. The present case may also be relevant to cases of mobile left atrial myxoma, in which tachycardia during TEE may increase the likelihood of fragmentation and subsequent embolization. This case illustrates the potential risk of TEE in patients with mobile left atrial masses and should be performed only if transthoracic echocardiography is nondiagnostic. IfTEE is considered necessary, maximum effort must be made to maintain hemodynamic stability during the procedure.
Embolization of LA thrombus during TEE 273
REFERENCES l. Bleifeld W. Transesophageal two-dimensional echocardiography for the detection of left atrial appendage thrombus. J Am
Coli Cardiol1986;7:163-6. 2. Acar J, Cormier B, Grimberg D, et a!. Diagnosis of left atrial thrombi in mitral stenosis-usefulness of ultrasound techniques compared with other methods. Eur Heart J 1991;12(suppl B):70-6. 3. Obeid Al, Marvasti M, Parker F, Rosenberg J. Comparison of transthoracic and transesophageal echocardiography in diagnosis of left atrial myxoma. Am J Cardiol 1989;63: 1006-8. 4. Daniel WG, Erbel R, Kasper W, eta!. Safety of transesophageal echocardiography. A multicenter survey of 10,419 examinations. Circulation 1991;83:817-21. 5. Wrisley D, Giambartolomei A, Lee I, Brownlee W. Left atrial ball thrombus: review of clinical and echocardiographic manifestations with suggestions for management. Am Heart J 1991;121:1784-90. 6. Sherman W, Nozad SE, Stoian A, Madias JE. Free-floating left atrial thrombus and systemic embolization. Chest 1985;87:694-5. 7. Arani DT, Carleton RA. The deleterious role of tachycardia in mitral stenosis. Circulation 1967;36:511-6. 8. Silvey SV, Stoughton TL, Pearl W, Collazo WA, Belbel RJ. Ruprure of the outer partition of aortic dissection during transesophageal echocardiography. Am J Cardiol 1991;68: 286-7.
