Is the Thrombus Truly Free-floating? A Case Report Kenan Demir, MD,1 Ahmet Avci, MD,1 Bulent Behlul Altunkeser,1 Nevzat Serdar Ugras2 1 2
Selcuk University, Selcuklu Faculty of Medicine Cardiology Department, Konya, Turkey Selcuk University, Selcuklu Faculty of Medicine Pathology Department, Konya, Turkey
Received 25 March 2013; accepted 30 August 2013
ABSTRACT: A free-floating thrombus in the left atrium is very rare in mitral stenosis. Such a thrombus can lead to sudden circulatory arrest and syncope or can cause severe cerebral or peripheral thromboembolic events. Clinical diagnosis is difficult, but left atrial thrombus should be suspected if patients with mitral stenosis and atrial fibrillation have intermittent or changing murmurs, emboli, or syncope. We describe the case of a patient with mild mitral stenosis under warfarin therapy, and a left atrial pedunculated thrombus discovered during the investigation C 2013 Wiley Periodicals, Inc. J for syncope attacks. V Clin Ultrasound 42:252–255, 2014; Published online in Wiley Online Library (wileyonlinelibrary.com). DOI: 10.1002/jcu.22102 Keywords: free-floating thrombus; mitral stenosis; atrial fibrillation; transesophageal echocardiography
free-floating thrombus in the left atrium (LA) is very rare in patients with mitral stenosis (MS). It usually occurs in the setting of dilated LA with stagnant flow, commonly the result of severe rheumatic MS and accompanying atrial fibrillation (AF).1 The free-floating thrombus can produce sudden circulatory arrest and syncope by obstructing the mitral orifice or can cause severe cerebral or peripheral thromboembolic events.2,3 Two-dimensional echocardiography is particularly useful for identifying left atrial free-floating thrombus and for demonstrating its behavior through consecutive cardiac cycles.4 Transesophageal echocardiography (TEE) is considered the gold standard modality in detecting left atrial/LA appendage thrombus because it provides superior visualization of posCorrespondence to: A. Avci C 2013 Wiley Periodicals, Inc. V
terior structures such as the LA and LA appendage, when compared with transthoracic echocardiography (TTE; with 100% specificity and 93.3% sensitivity).5 We describe the case of a patient with mild MS and a left atrial pedunculated thrombus, who had syncope attacks under warfarin therapy. TTE showed a floating thrombus, which was later demonstrated by TEE to be pedunculated. CASE REPORT
A 67-year-old woman with mild MS was admitted to our hospital with paroxysmal palpitations and episodes of syncope, which started 3 months before admission. Six months ago, TEE examination had been performed in another clinic, but reported neither left atrial mass nor spontaneous echo-contrast; the electrocardiogram (ECG) showed normal sinus rhythm. At admission, the patient was in AF (heart rate5 110 beats/min). The first heart sound was loud, and there was an opening snap and a loud apical mid-diastolic murmur, changing depending on the patient’s position. The neurologic examination was normal. She regularly received warfarin 27.5 mg per week. The international normalized ratio (INR) was 1.64. TTE showed the stenotic rheumatic mitral valve (mitral valve area 5 1.34 cm2), normal left ventricular dimensions and systolic functions, left atrial dilatation (5.4 cm), and a 3.0 3 2.6-cm mobile floating mass in the LA (Figure 1). This mass caused complete intermittent occlusion of the stenotic mitral valve. TEE examination was performed subsequently and demonstrated that the mobile mass was not really free-floating because it was pedunculated and originated from the JOURNAL OF CLINICAL ULTRASOUND
IS THE THROMBUS TRULY FREE-FLOATING
FIGURE 2. Transesophageal echocardiogram demonstrates the ballshaped thrombus attached by a pedicle to the atrial appendage wall.
FIGURE 1. Transthoracic echocardiogram, apical four-chamber view, demonstrates a ball-shaped thrombus in the left atrium.
atrial appendage wall (Figure 2). The patient underwent urgent cardiac surgery for removal of this pedunculated thrombus from the LA and mitral valve replacement. Macroscopic and histologic examination confirmed that it was a thrombus (Figure 3).
Large population studies on the epidemiology of rheumatic valvular heart diseases in Turkey are scarce. According to the Turkish Adults Risk Factor Study (TEKHARF) published in 2000, the incidence of rheumatic heart disease was 2% in men and 7% in women, but their rates have been decreasing since then.6 AF is a common arrhythmia and a major cause of morbidity and mortality from stroke and thromboembolism, usually due to embolization from thrombi formed within the fibrillating LA and its appendage.7 AF is a frequent complication of MS. A left atrial mural thrombus is a common finding, particularly in the left atrial appendage, in patients with mitral valve disease and AF. Specifically, patients with MS who develop AF increase their risk of cardioembolism by three to seven times.8 Therefore, all patients having MS with AF need long-term anticoagulation therapy. In our case, the patient was receiving warfarin, but the dose was insufficient (INR: 1.64). Six months ago, the thrombus was not seen at the TEE, whereas ECG showed sinus rhythm. The thrombus may have formed in our patient because of the development of AF and inadequate warfarin therapy. VOL. 42, NO. 4, MAY 2014
A free-floating ball-thrombus is a rare occurrence in patients with MS. It is an uncommon finding, which was reported in 1 of 3000 autopsies, but it has potentially fatal effects.7 In the opinion of Hewitt,9 the diagnosis of a freefloating ball-thrombus should be based on two criteria: the thrombus must be larger than the orifice of the valve, and it must have a smooth surface with no signs of attachment to the atrial wall. A free-floating thrombus is thought to originate as a small mural thrombus, usually on the interatrial septum but rarely in the left atrial appendage. The thrombus gradually enlarges and forms a projecting mass that remains attached to the atrial wall by a pedicle. As the bulbous end of the thrombus enlarges, its pedicle lengthens and thins until the thrombus eventually breaks free. Thereafter, as the thrombus spins freely in the atrium, it acquires its characteristic smooth, polished appearance.3 Thus, in our case, the thrombus was still pedunculated and not really free-floating. Clinical diagnosis is difficult, but left atrial thrombus should be suspected if patients with MS and AF have intermittent or changing murmurs, emboli, or syncope. Variations in symptoms have also been associated with changes in the posture or position of the patient; exacerbation of dyspnea can occur when the patient is sitting.3 The clinical course could also be asymptomatic, and the diagnosis made as an incidental echocardiographic finding.7 The mobile mass we detected in the LA closed the mitral valve orifice during diastole, which could explain syncopes. When clinical evidence leads to the suspicion of a free-floating thrombus, echocardiography 253
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FIGURE 3. Macroscopic image of a cut section the pedunculated thrombus, and histologic examination shows the structure consisting of fibrin and blood cells (3400).
should be performed immediately. In most published cases, the free-floating thrombus has been either described by TTE or demonstrated surgically to be spherical or ovoid in shape, but TEE findings were not reported.1,10–13 In the present case, we initially thought that the mass in the LA was a free-floating thrombus, because it appeared to be spherical, like a ball-thrombus, on TTE. Nevertheless, TEE showed it was attached by a pedicle to the atrial appendage wall. The differential diagnoses of LA thrombus are myxoma and other cardiac masses. TEE is considered the gold standard modality in detecting left atrial/LA appendage abnormalities. Nevertheless, TEE also has a few absolute and some relative contraindications. Therefore, other imaging modalities such as cardiac CT and cardiac MRI also may be used for imaging the left atrial thrombus. The presence of a free-floating thrombus suggests a high embolic risk. In our patient, however, we think that her syncopal episodes were caused by intermittent mitral orifice occlusion by pedunculated thrombus rather than by embolisms. To conclude, patients with MS should be followed closely for the development of AF, and 254
their INR should be checked more frequently for adequate anticoagulation. Patients with syncope should be examined as soon as possible with TTE, and TEE if required, especially for the differential diagnosis between free-floating and pedunculated thrombus, although both need emergency surgery.
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tomography in patients with atrial fibrillation a meta-analysis. Circ Cardiovasc Imaging 2013;6:185 Onat A, Sansoy V, Soydan I, et al. T€ urk eriskinlerde lıg ı, risk profili ve kalp sag lıg ı. Ohan, Istankalp sag bul, 2000. Turk Kardiyol Dern Ars 1991;178:185. Espinola JEM, Colman MIA, Centurion OA. Uneventful disappearance of a large left atrial ball thrombus with enoxaparin in a patient with mitral stenosis associated with pregnancy. Open Cardiovasc Med J 2011;5:212. Marmagkiolis K, Nikolaidis IG, Politis T, et al. Approach to and management of the acute stroke patient with atrial fibrillation: a literature review. J Hosp Med 2008;3:326. Hewitt JH. Free thrombi and ball thrombi in the heart. Johns Hopkins Hosp Rep 1915;1:17.
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