Left ventricular (LV) thrombus formation is a known complication associated with acute myocardial infarction and other conditions that impair LV function, carrying a risk for systemic embolization.^1,2 In this report, we describe a case in which an emergent aortic cross-clamp was applied in an attempt to prevent a thrombus, which had dislodged from the LV apex into the LV outflow tract (LVOT), from migrating into the systemic circulation. However, it was later discovered that the thrombus had already migrated into the systemic circulation as an embolus before the aortic cross-clamp. It is believed that stopping cardiopulmonary bypass (CPB) while the heart was still beating, followed by cross-clamping the aorta, contributed to the thrombus migration. Our findings suggest that for a free-floating LV thrombus, the aortic cross-clamp should be applied with adjustments to CPB flow to keep the aortic valve closed or by optimizing venous drainage to empty the cardiac chambers and prevent ejection of the thrombus.

A 53-year-old male patient presented with continuous chest pain for approximately 3 hours before visiting a nearby clinic. The patient was then transported by an ambulance to our hospital, arriving 4 hours after symptom onset. The patient was diagnosed with an acute ST-segment elevation myocardial infarction (STEMI), with severe anteroseptal hypokinesis and an LV ejection fraction of approximately 40%. The patient immediately underwent percutaneous coronary intervention for total occlusion of the mid left anterior descending coronary artery, successfully achieving recanalization with a drug-eluting stent. On the 13th day after onset, because of an elevated D-dimer level of 3.5 μg/mL, transthoracic echocardiography (TTE) and contrast-enhanced computed tomography (CT) were performed, revealing an intraventricular thrombus at the apex of the left ventricle (Figures 1 and 2, Video 1). Continuous heparin infusion was immediately initiated, and warfarin therapy was started the following day. On the 15th day after the onset of STEMI, the patient reported left-sided hemiparesis, prompting an emergency magnetic resonance imaging scan. The scan revealed high signal intensity on diffusion-weighted imaging in the right middle cerebral artery territory; however, magnetic resonance angiography confirmed that there was no occlusion in the major cerebral arteries. The left-sided hemiparesis symptoms completely resolved within 2 hours of stroke onset. A consultation with a neurologist confirmed the diagnosis of a cardioembolic stroke caused by an LV thrombus. Consequently, surgical LV thrombectomy was scheduled for the following day.