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Table of Contents    
Year : 2021  |  Volume : 69  |  Issue : 3  |  Page : 770-771

Bilateral Symptomatic Carotid Free Floating Thrombi

1 Department of Neurology, Yashoda Hospital, Secunderabad, Telangana, India
2 Department of Neurology, National University Hospital, Lower Kent Ridge Rd, Singapore

Date of Submission13-Aug-2018
Date of Decision25-Sep-2018
Date of Acceptance01-Dec-2019
Date of Web Publication24-Jun-2021

Correspondence Address:
Dr. Suresh Giragani
Department of Neuroradiology and Interventional Radiology, Yashoda Hospitals, Alexander Road, Secunderabad - 500 003, Telangana
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/0028-3886.319231

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How to cite this article:
Giragani S, Komal R N, Potluri A, Sharma VK. Bilateral Symptomatic Carotid Free Floating Thrombi. Neurol India 2021;69:770-1

How to cite this URL:
Giragani S, Komal R N, Potluri A, Sharma VK. Bilateral Symptomatic Carotid Free Floating Thrombi. Neurol India [serial online] 2021 [cited 2021 Jul 25];69:770-1. Available from:


Free Free-floating carotid thrombus is an uncommon entity. The incidence of bilateral free free-floating carotid thrombosis is even rare.[1] A 62-year-old woman presented to our tertiary center with right-sided weakness of sudden-onset for six days and clumsiness of left hand for four days. Mild weakness was noted in the right upper and lower limbs (power Medical Research Council grade 4/5). Examination of the left extremities revealed mild dysmetria of the upper limb. Diffusion weighted imaging (DWI) of the brain [Figure 1]a and [Figure 1]b showed areas of diffusion restriction in bilateral centrum semiovale, right fronto-parietal region and corresponding hyperintensity in fluid attenuation inversion recovery (FLAIR) image [Figure 1]c. Computed tomographic angiography (CTA) revealed eccentric filling defects in the right common carotid [Figure 1]e and left internal carotid artery (ICA) [Figure 1]f. Carotid duplex ultrasonography [Figure 2]a and [Figure 3]a revealed a subacute thrombus attached to the near wall of right CCA and an acute thrombus in left carotid bulb and proximal ICA, with circumferential blood flow at the distal aspect and cyclical motion with each cardiac cycle. Her procoagulant work up demonstrated the very low activity of Protein C [12%(67–195%)] while the levels of protein S and Anti-Thrombin III were normal. Prothrombin gene 20210 mutation and MTHFR gene mutations were negative. Hemoglobin, platelet count, coagulation screen, and homocysteine were within normal limits. Anti B2 glycoprotein antibodies and lupus anticoagulant were not detected. Patient was started on subcutaneous low molecular weight heparin (LMWH) and duplex scan performed after 4 days [Figure 2]c and [Figure 3]c showed a significant reduction in the thrombus burden in both carotid arteries, accompanied by complete neurological recovery. LMWH was converted to warfarin, and cervical duplex sonography on day 32 showed complete resolution of right CCA thrombus [Figure 2]d. Left ICA showed a complete resolution of thrombus on day 45 [Figure 3]d. She was kept on long-term oral anticoagulation and has remained asymptomatic for the past one year.
Figure 1: MRI DWI images (a and b) showing diffusion bright foci in bilateral centrum semiovale and right frontoparietal region. FLAIR image (c) showing right fronto-parietal hyperintensity. MRA image (d) showing normal intracranial vessels. CTA images (e and f) showing eccentric hypodensity in right CCA anterior wall (thin arrow) and a central hypodensity with circumferential contrast around it in left ICA (thick arrow)

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Figure 2: Duplex (a) and grayscale ultrasound (b) of right CCA showing isoechoic thrombus (arrows) on the anterior wall of CCA with increased peak systolic velocities in the CCA segment. Note the cranial end of the thrombus free-floating component (arrowheads). Follow-up scans on day 4 (c) and on day 32 (d and e) showing interval gradual resolution of the thrombus

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Figure 3: Duplex (a) and grayscale ultrasound (b) of left ICA showing iso to hyperechoic thrombus in the left ICA with circumferential flow around the tip of the thrombus. Follow up scans on day 4 (c) and on day 45 (d and e) showing interval gradual resolution of the thrombus

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Free-floating thrombus of the carotid artery is defined as an elongated thrombus attached to the arterial wall with circumferential blood flow in a cyclic motion at its distal end.[2] The reported incidence of floating carotid thrombus ranges from 0.4% to 1.5% in patients with ischemic cerebrovascular disease.[2] We could find only one previous report describing bilateral carotid thrombi, demonstrated on conventional angiography.[1] The presence of carotid mural thrombi without underlying atherosclerotic changes is relatively uncommon.[3] The thrombi commonly occurred in the setting of underlying atherosclerotic plaque or cardiac pathology.[2],[3],[4] On the contrary, our patient did not show any atherosclerosis in the carotid arteries or cardiac thrombi. A very low level of protein C was the only identifiable cause of arterial thrombi in our patient. Although all routinely used imaging methods (catheter angiography, CTA, MRA, and duplex sonography) can demonstrate a carotid artery thrombus,[2],[4] duplex sonography retains its important place due to its portability and direct visualization.[5] Urgent anticoagulation remains the mainstay in the treatment of free-floating carotid thrombi. Urgent thrombo-endarterectomy or endovascular clot extraction is employed in highly selected patients.[4],[6] Interestingly, the clinical outcomes from various treatment modalities are reported to be similar.[2] We did not consider acute intervention for clot removal in our patient due to the stable neurological deficits and absence of radiological blood flow limitation in the distal carotid artery and in the intracranial circulation.

We present a rare occurrence of simultaneous bilateral free free-floating carotid thrombi. Early diagnosis and timely initiation of anticoagulation resulted in rapid recovery and prevented potentially catastrophic complications. Our report highlights the role of ultrasound imaging in diagnosis and longitudinal follow-up of patients with carotid thrombi.

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Conflicts of interest

There are no conflicts of interest.

  References Top

Buscaglia LC, Macbeth A. Bilateral carotid artery thrombosis in a young man. J Vasc Surg 1993;17:790-3.  Back to cited text no. 1
Bhatti AF, Leon LR Jr, Labropoulos N, Rubinas TL, Rodriguez H, Kalman PG, et al. Free- floating thrombus of the carotid artery: Literature review and case reports. J Vasc Surg 2007;45:199-205.  Back to cited text no. 2
Delgado MG, Vega P, Roger R, Bogousslavsky J. Floating thrombus as a marker of unstable atheromatous carotid plaque. Ann Vasc Surg 2011;25:1142.e11-7.  Back to cited text no. 3
Ferrero E, Ferri M, Viazzo A, Labate C, Pecchio A, Berardi G, et al. Free-floating thrombus in the internal carotid artery: Diagnosis and treatment of 16 cases in a single center. Ann Vasc Surg 2011;25:805-12.  Back to cited text no. 4
Chua HC, Lim T, Teo BC, Phua Z, Eng J. Free-floating thrombus of the carotid artery detected on carotid ultrasound in patients with cerebral infarcts: A 10-year study. Ann Acad Med Singapore 2012;41:420-4.  Back to cited text no. 5
Parodi JC, Rubin BG, Azizzadeh A, Bartoli M, Sicard GA. Endovascular treatment of an internal carotid artery thrombus using reversal of flow: A case report. J Vasc Surg 2005;41:146-50.  Back to cited text no. 6


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