Background

Floating right heart thrombi are uncommon but their true prevalence is unknown [₁]. In most cases, they are transit from the legs to pulmonary arteries and thus are a form of venous thromboembolic disease [₂]. They can embolize at any moment and emergency treatment is required especially in view of their documented dismal prognosis [₃].

Malignant disease is an independent predisposing factor for hypercoagulability. Breast cancer and use of tamoxifen have already been suspected for hpercoagulability abnormalities and thrombi formation [₄].

A case of a 67-year-old female with a history of breast cancer and a free-floating thrombus in the right atrium is presented.

Case presentation

A 67-year-old woman presented to our department with dyspnea, chest pain and occasional dizzy spells. Her past medical history revealed that she underwent modified radical mastectomy for breast cancer 5 years ago. Postoperatively she treated with adjuvant chemoradiotherapy and tamoxifen. Clinical examination revealed cyanosis, hepatomegaly and pretibial oedema. Laboratory data was normal except for leukocytosis (14000/mm³) and elevated erythrocyte sedimentation rate (62mm/1h). Electrocardiogram showed sinus tachycardia and right bundle branch block. Chest x-ray revealed cardiomegaly. Transthoracic echocardiography showed a large mobile thrombus within the right atrium which sometimes prolapsed through the tricuspid valve into the right ventricle (Figure 1).

Figure 1

Figure 1: A large mobile thrombus within the right atrium which sometimes prolapsed through the tricuspid valve into the right ventricle.

No thrombosis was detected at venous doppler ultrasound examination. Abdominal ultrasound showed prominent inferior vena cava and dilated hepatic veins with minimal ascites. Additional investigation (thorax an abdominal computed tomography) was normal.

Because of the risk of pulmonary thromboembolism and acute obstruction of the tricuspid valve, emergency surgery was performed. The patient underwent surgical embolectomy with exploration of the right chambers and pulmonary arteries under full cardiopulmonary by pass. A lage free serpentine right atrial thrombus was removed (Figure 2).

Figure 2

Figure 2: A large free serpentine right atrial thrombus was removed.

The patient had an uneventful recovery. Her postoperative transthoracic echocardiogram showed good right ventricular contractility with no residual thrombus in the right atrium.

Screening tests for hypercoagulability included normal levels of serum fibrinogen , d-dimers, protein C and S, antithrombin III but positive antiphospholipid antibodies.

After a period of subcutaneous low molecular weight heparin, the patient was discharged on oral anticoagulation (acenocoumarol), adjusted to maintain an international normalized ratio (INR) between 2 and 3 times control. Eighteen months later, the patient is free of symptoms and with no recurrence of malignant disease.

Discussion

Free floating right heart thrombi are a rare phenomenon, generally diagnosed when echocardiography is performed in patients with suspected or proven pulmonary embolism and have a dismal prognosis. Severe pulmonary embolism usually coexists with floating right heart thrombi [₅].

Sometimes the differential diagnosis of a floating right heart thrombus may be difficult. Congenital structures such as Chiari network, persistent eustachian or thebesian valves, atrial septal aneurysms or acquired conditions such as intracardiac tumors, devices and vegetations need to be considered [₆,₇,₈]. Any doubt should lead to the performance of transesophageal echocardiogram which is rapid, semi-invasive bedside investigation. According to most authors, diagnosis of floating right heart thrombus by echography allows immediate treatment and additional investigations (lung scintigraphy, computed tomography scan, pulmonary angiography) may be performed after treatment [₁,₃]. Floating right heart thrombi are an extreme therapeutic emergency and any delay to treatment could be lethal [₉,₁₀]. Twenty one percent of the patients die within the first day of admission [₉].

The role of surgery for severe pulmonary embolism with or without concomitant floating right heart thrombus has been widely discussed [₁₁]. Thrombolysis may be advocated first [₁₂,₁₃]. Thrombolysis has the advantage of acting in the intracavitary thrombus, on the pulmonary pole and at least partially on deep vein thrombosis which is usually seen in association [₁₄]. The potential risks are the migration of fragments following clot lysis in patients with an unstable hemodynamic ondition or a recurrence of embolism following partial dissolution of the venous thrombus [₁₀].

In our case, due to the risk of pulmonary thromboembolism and acute obstruction of the tricuspid valve, emergency surgery was performed altough thrombolysis could be the first line treatment. In fact only a prospective multicenter rndomized trial will be enable to determine the real incidence of mobile heart thrombus in acute pulmonary embolism and the codification the respective indication for medical or surgical treatment.