Central Journal of Cardiology & Clinical Research

Cite this article: Kim JG, Lee SJ (2015) Two Cases with Free-Floating Thrombus in the Common Carotid Artery. J Cardiol Clin Res 3(2): 1047.

*Corresponding author

Soo Joo Lee, Department of Neurology, University Hospital, Eulji University, School of Medicine, 95 Dunsanseoro, Seo-gu, Daejeon, 35233, Republic of Korea, Tel: 82-42-611-3430; Fax: 82-42-611-3858; Email:

Submitted: 02 October 2015

Accepted: 19 November 2015

Published: 21 November 2015

Copyright© 2015 Lee et al.

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Keywords•Carotid artery•Free-floatingthrombosis•Duplex ultrasonography

Case Report

Two Cases with Free-Floating Thrombus in the Common Carotid ArteryJae Guk Kim and Soo Joo Lee*Department of Neurology, Eulji University, Korea

Abstract

Two patients had multiple embolic infarctions in the middle cerebral artery territory. Free-floating thrombi adherent to plaques were detected in the common carotid artery near the bifurcation using duplex ultrasonography. Further strokes did not occur under anticoagulation. The free-floating thrombi disappeared on follow-up sonography. Carotid duplex ultrasonography is useful for recognizing free-floating arterial thrombi and for monitoring dynamic changes. Treatment of these thrombi remains controversial; however anticoagulation alone may be sufficient to prevent further strokes.

INTRODUCTIONAtheromatous lesions in the extracranial carotid artery may

cause local thrombus formation and may be a source of migrating clots. The pathogenesis of such artery-to-artery emboli is based more on the plaque morphology than on the severity of stenosis in the affected artery [1]. Ulcerated plaques with dislodged debris and intraplaque hemorrhage are believed to be responsible for emboli production [1]. Floating thrombi has been more frequently detected by echocardiography in the aorta and heart than in the carotid artery [2,3]. Free-floating thrombiin the extracranial internal carotid artery (ICA) and carotid bifurcation have occasionally been described before [4-6]. Free-floating thrombus in the common carotid artery (CCA) has been reported in a few studies [7-9]. The CCA is a less common atheromatous site than the carotid artery bifurcation and adjacent ICA portion. In order to detect such atherosclerotic lesions, real-time B-mode duplex ultrasonography has been applied at the carotid bifurcation. Carotid duplex scans are posited to be a useful method to disclose these floating thrombi. We recently encountered these uncommon findings in two patients that we now describe.

CASE PRESENTATION

Case 1

A seventy-year-old man was admitted to our hospital because he developed a sudden right hemiparesis and aphasia. He had a history of diabetes mellitus and cigarette smoking for fifty years. On examination, he had a right hemiparesis with Babinski’s sign in the right side. He had a transcortical sensory aphasia. MRI (1.5T Scanner, Magnetom Sonata, Siemens, Germany) one day after symptom onset showed multiple infarctions involving the left middle cerebral artery territory (Figure 1a). MR angiography (MRA) showed slightly decreased flow signal in the left CCA, but no

definite stenotic lesion was seen at the carotid artery bifurcation level (Figure 1b). The initial carotid duplex using ATL Ultramark 9 system (Advanced Technology Laboratories, Bothell, WA), which contains a 4-7 MHz real-time B-mode imaging’s, showed a 3 cm mural free-floating thrombus adherent to an atheromatous plaque in the left CCA about 1 cm below carotid bifurcation (Figure 2a). This was considered to be a floating thrombus due to oscillation of its free end in the blood stream. Both transthoracic and transesophageal echocardiograms showed no potential source of embolism in the heart and aorta. Routine biochemical

Figure 1 (a) Multifocal high signal intensities on diffusion weighted image at the left insula, subinsula, fronto-parietal cortex and white matter area demonstrate multiple embolic infarctions involving the left middle cerebral artery territory. (b) MR angiography shows slightly decreased flow signal in the left CCA (arrow), but no definite stenotic lesion was seen at the carotid artery bifurcation level.

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and hematological tests, including prothrombin time, partial thromboplastin time, and platelet count, were normal. Anticoagulation was started one day after stroke onset. Follow-up duplex sonography on the 5th day after stroke onset showed disappearance of the floating thrombus (Figure 2b). No further clinical events occurred during anticoagulation over a follow-up period of one year.

Case 2

A 57-year-old man was admitted to our hospital because of sudden right side weakness. He had a history of cigarette smoking for thirty years. Five days before admission, he noted sudden weakness of right upper extremity. On admission, weakness of the right lower extremity newly developed. On neurological examination, he showed right hemiplegia with Babinski’s sign. MRI showed infarctions involving the left front parietal cortex with slight hemorrhagic conversion. Neck MRA was normal. Electrocardiograph and transthoracic echocardiograms were normal. Routine biochemical and hematological tests were normal except for increased GOT/GPT level. Antiplatelet agents were administered initially. Duplex scans of the left CCA showed mural

small 5-mm-sized floating thrombus adherent to an atheromatous plaque in middle portion of the CCA below the bifurcation (Figure 2c). Also, it showed focal small plaque extending to the origin of the left ICA, causing a moderate 40-50% stenosis. We started anticoagulation immediately after identifying this lesion on the fourth hospital day. A follow-up duplex scan on the 7th day after anticoagulation showed consolidation of the floating thrombus. No further clinical events occurred under anticoagulation during 8-month follow-up.

DISCUSSION Floating or mobile thrombi in the extracranial carotid artery

are rarely discovered in angiography or duplex sonography [4-9]. In one study this uncommon lesion was found in one among more than 2000 patients examined. The morphology and characteristics of plaque are routinely examined on duplex ultrasonography of the carotid artery. Unstable carotid artery plaques play an important role in embolic infarction. Plaque ulceration and intraplaque hemorrhage are common finding in patients with ischemic stroke [1]. However; floating thrombi have only occasionally been described before. They developed because of disruption of plaque surface (ulceration) resulting in adherence of pedunculated debris to the plaque. Free-floating thrombus was defined as an elongated thrombus attached to the arterial wall with circumferential blood flow at its distal most aspect [4].

Since previously dislodged floating plaques or emboli from an ulcerated plaque might cause infarction or TIA, the detection of these lesions is very important. Sometime large floating thrombi at the carotid bifurcation are visualized on angiography [10]. Angiography may fail to visualize small clots and distinguish laminated thrombi from atheromatous deposits. High-resolution B-mode ultrasonography has allowed direct visualization of changes in the arterial wall that can be distinguished by their echo pattern. Organized, old thrombi are usually better recognized than recent red thrombi by B-mode ultrasonography [11]. The floating thrombi in our two patients were better visualized by duplex ultrasonography than by MR angiography. We followed up these lesions by duplex ultrasonography, and were easily able to identify disappearance of these floating thrombi.

Our two patients were treated with anticoagulation, and there was neither further stroke nor complication. Treatment of control thrombi remains controversial [5]. Emergent endartectomy may be beneficial, but potentially carries a high risk of neurologic complication, either by iatrogenic embolism from friable plaque or by possibly aggravation of brain ischemia from carotid artery clamping. Thrombolytic therapy may be effective, but carries a risk of breaking of unstable segments of plaque or thrombi with subsequent embolization [12]. Anticoagulation has been reported to be effective in treating free-floating intra-luminal thrombi [7], but some recommend withholding treatment during the first few days in the patients with severe neurologic deficits and large infarct. The potential mechanisms of disappearance of floating thrombi under anticoagulation may be red clot lysis, distal embolization, and spontaneous fibrinolysis.

In summary, carotid duplex ultrasonography with high-resolution real time B-mode system in acute stroke is useful for

Figure 2 (a) The sagittal view of duplex sonography at left CCA shows large free-floating thrombus (arrow) adherent to plaque. (b) The large free-floating thrombus disappears on follow-up duplex sonography on the fifth day after anticoagulation. (c) Duplex scans of the left CCA reveals mural small 5-mm-sized floating thrombus (arrow) adherent to an atheromatous plaque in middle portion of the CCA below the bifurcation.

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Kim JG, Lee SJ (2015) Two Cases with Free-Floating Thrombus in the Common Carotid Artery. J Cardiol Clin Res 3(2): 1047.

Cite this article

recognizing free-floating thrombi and for monitoring dynamic changes. Treatment of infarction associated with carotid floating or mobile thrombi remains controversial, however, anticoagulation was sufficient to prevent further stroke in our patients without surgical intervention.

REFERENCES1. Fisher M, Blumenfeld AM, Smith TW. The importance of carotid artery

plaque disruption and hemorrhage. Arch Neurol. 1987; 44: 1086-1089.

2. Glikson M, Agranat O, Ziskind Z, Kaplinski E, Vered Z. From swirling to a mobile, pedunculated mass-the evolution of left ventricular thrombus despite full anticoagulation. Echocadiographic demonstration. Chest 1993; 103: 281-283.

3. Kalangos A, Baldovinos A, Vuille C, Montessuit M, Faidutti B. Floating thrombus in the ascending aorta: a rare cause of peripheral emboli. J Vasc Surg. 1997; 26: 150-154.

4. 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.

5. 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: 805-812.

6. 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: 420-424.

7. Alurkar A, Karanam LS, Nayak S, Oak S. Idiopathic thrombus in the common carotid artery on digital subtraction angiography. J Clin Imaging Sci. 2012; 2: 20.

8. Taguchi E, Nishigami K, Kamio T, Honda T, Nakao K. Free-floating thrombus in the right common carotid artery. J Cardiol. 2009; 54: 304-306.

9. Silver B, Gulka I, Nicolle M, Sahjpaul R, Hachinski V. Idiopathic free-floating thrombus of the common carotid artery. Can J Neurol Sci. 2002; 29: 97-99.

10. Chiras J, Bories J, Barth MO, Aymard A, Poirier B. Cerebral angiography in ischemic strokes. Neuroradiology. 1985; 27: 521-538.

11. Wetzner SM, Kiser LC, Bezreh JS. Duplex ultrasound imaging: vascular applications. Radiology. 1984; 150: 507-514.

12. Yasaka M, Yamaguchi T, Yonehara T, Moriyasu H. Recurrent embolization during intravenous administration of tissue plasminogen activator in acute cardioembolic stroke. A case report. Angiology 1994; 45: 481-484.