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
A 53-year-old female with atrial fibrillation underwent transesophageal echocardiography for a suspected cardiac source of a thromboembolic episode. A thrombus was identified in the left atrial appendage. During the transesophageal echocardiography, the thrombus disappeared, under direct visualization, from the left atrial appendage. Four hours later, the patient developed a stroke. We believe that this is the first case describing direct visualization of left atrial thrombus migration in the English-language literature. Sequential frames are shown in the Figure.
The development of neurological symptoms 4 hours (rather than immediately) after visualized thrombus migration is of interest. The luminal diameter of the internal carotid artery is highly variable, but it is unlikely that a 2×1-cm thrombus entered the carotid artery system. We hypothesize that the observed clot migration was not the culprit event but that there were subsequent emboli, despite a therapeutic activated partial thromboplastin time level of intravenous unfractionated heparin, resulting in the stroke. Data from carotid artery stenting studies1,2 suggest that this time interval is somewhere in the range of a few minutes to a few hours, which is consistent with the time line of events seen in our patient.
Dr Van Decker has received grants from GE Healthcare Nuclear Imaging and Oncology Chemotherapeutic Protocols and has served on the speakers bureau for and received honoraria from Molecular insights. The other authors report no conflicts.