Migration of Large Thrombus From the Left Atrial Appendage During Transesophageal Echocardiography in a Stroke Patient

A 79-year old man visited hospital with a 6-h history of left-sided motor weakness via another hospital. He did not have any medical history including arrhythmic heart disease, and initially had normal sinus rhythm on electrocardiogram. Brain magnetic resonance imaging (MRI) showed a large embolic infarction of the right middle cerebral artery territory. Thrombolytic therapy with Actylase^® (alteplase [recombinant tissue-type plasminogen activator]; Boehringer Ingelheim, Basel, Switzerland) 0.9 mg/kg body weight was given according to the guidelines for acute ischemic stroke.¹ Dual antiplatelet therapy with aspirin 100 mg and clopidogrel 75 mg was also started and he was admitted to the intensive care unit.

After 5 days his condition stabilized and the patient underwent transesophageal echocardiography (TEE) to locate the source of the intracardiac embolism. Remarkably, a 2.8-cm×1.4-cm, highly mobile, wriggling tadpole-like thrombus with an echolucent center was observed in the left atrial appendage (LAA) with a dense spontaneous echo contrast. During TEE, the thrombus travelled out of the appendage, leaving only a small remnant (0.5×0.8 cm), and we were able to catch the exact moment of thrombus detachment (Figure 1; Movie S1). As soon as it moved out of view, a thorough neurological examination was carried out, but there were no newly developed neurologic symptoms or signs due to the thrombus. Anticoagulation therapy was started immediately with i.v. unfractionated heparin and subsequent warfarin within the target therapeutic range (target activated partial thromboplastin time range for heparin, 1.5–2.5-fold the control value; target international normalized ratio range for warfarin, 2–3), and dual antiplatelet therapy with aspirin and clopidogrel was stopped. The next day, follow-up brain MRI showed a new small lesion in the left cerebellum besides the existing large infarcted lesion, as compared with the previous images (Figure 2). The new lesion, however, was regarded as an insignificant nidus. On hospital day 16, his condition had gradually improved, and he was discharged without any other significant neurologic complications. After 3 months of follow-up under warfarin therapy, there were no further visible thrombi or spontaneous echo contrast on TEE.

Figure 1.

Transesophageal echocardiography arranged in chronological order, showing the movement of a left atrial appendage (LAA) thrombus over a few seconds. (A) A 2.8×1.4-cm large thrombus (white hollow arrow) in the LAA. (B–E) The thrombus migrates into the left atrium (LA). (F) A small remnant thrombus (white thick arrow) attached to the LAA wall. LV, left ventricle.

Figure 2.

(A,B) Initial diffusion-weighted brain magnetic resonance imaging, showing a right middle cerebral artery infarction. (C,D) Diffusion-weighted brain magnetic resonance imaging of the next day, showing a newly developed small lesion (arrow) in the right cerebellum.

There have been very few cases of visualization of the exact moment of thrombus detachment and embolization on TEE,^2,3 and even fewer studies on the characteristics of LAA thrombus with higher embolic risk.⁴ LAA thrombus is an important source of embolic stroke. Understanding of its complex and extremely variable structure and careful observation of the echocardiographic appearance of the thrombus formation, may provide valuable supplementary information for the evaluation and management of thromboembolic events. Hence, we would like to share this uncommon case.

Disclosures

The authors declare no conflict of interest.

Supplementary Files

Supplementary File 1

Movie S1. This transesophageal echocardiography movie shows the exact moment of highly mobile, large thrombus running away from the left atrial appendage into left atrium.

Please find supplementary file(s);

http://dx.doi.org/10.1253/circj.CJ-16-1301

References

• 1.   Jauch EC, Saver JL, Adams HP Jr, Bruno A, Connors JJ, Demaerschalk BM, et al. Guidelines for the early management of patients with acute ischemic stroke: A guideline for healthcare professionals from the American Heart Association/American Stroke Association. Stroke 2013; 44: 870–947.
• 2.   Parekh A, Jaladi R, Sharma S, Van Decker WA, Ezekowitz MD. 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.
• 3.   Hernandez Gonzalez I, Navas Lobato MA, Muncharaz JF. Dislodgement and embolization of a left atrial appendage thrombus. Rev Esp Cardiol (Engl Ed) 2014; 67: 1054.
• 4.   Abe Y, Asakura T, Sakamoto N, Ishikawa S, Muroi S, Saitoh F, et al. Embolic attack in patients with atrial fibrillation and atrial thrombus depends on the character of the thrombus. Circ J 2003; 67: 203–208.