Free-floating thrombus in stroke patients with nonstenotic internal carotid artery-an ultrasonographic study

There are multiple causes of free-floating thrombus (FFT) formation in carotid arteries. The purpose of this study was to evaluate the incidence and natural history of FFT in nonstenotic internal carotid arteries of patients with acute ischemic stroke.

During a 50-month period, 3,200 consecutive patients with acute ischemic stroke were evaluated for internal carotid artery stenosis and the presence of FFT by color-coded duplex ultrasonography. Diagnostic workup included brain CT, transthoracic echocardiography, Holter electrocardiogram, and hypercoagulability state evaluation.

We found an FFT in 5 (0.18%) of 2,757 patients with acute stroke and nonstenotic internal carotid artery (mean age 44 years). The underlying pathology was hypercoagulable state in active pulmonary tuberculosis (n = 1), essential thrombocythemia (n = 1), thrombotic complications of nonstenotic plaques (n = 1), unknown (n = 2). All patients clinically improved under antiplatelet therapy. Follow-up color-coded duplex ultrasonography showed complete dissolution of FFT in all cases. There was no stroke recurrence.

Internal carotid artery FFT could be found in young stroke patients without identifiable arterial disease and could be resolved with antithrombotic treatment.