Inhibition of SA Node at Supine Position in Right Atrial Thrombus Complicating Behçet’s Disease – From Cardiac Surgical Point of View

Background

Intra-cardiac thrombus (ICT) complicating Behçet’s disease (BD) is extremely rare; only 50 cases have been registered worldwide [1–5]. In general, cardiac manifestations in BD include cardiomegaly, pericarditis, endocarditis, and rarely myocardial infarction and myocarditis [6,7].These cardiac manifestations, which are indication of poor prognosis, have been reported to occur in about 1–5% of cases [8]. CT scan and echocardiogram are excellent modalities for diagnosis and patient assessment. Cardiac surgical intervention can be done safely using on-pump or off-pump techniques when medical management fails.

Case Report

SURGICAL PROCEDURE:

Classical on-pump open-heart surgery with cross clamp could not be carried out because the subclavian, femoral veins, and superior and inferior vena cavas were thrombosed. We instead used on-pump beating heart technique. The HR was 32 bpm on the operating table.

The sternum was opened, heparinization was as usual for the possibility of cannulation on-pump techniques. Unfortunately, the superior and inferior vena cavas were thrombosed and cord like, the right atrium was small due to thickened wall and organized thrombus (Figure 3). Aortic cannula was inserted, but the venous cannula failed to fit inside the atrium down to inferior vena cava due to a small right atrial cavity and thrombosed inferior vena cava, so the venous cannula was taken out and two pump suctions were used to return the venous blood from inside the right atrium and from outside (mediastinum) to the heart-lung machine. This enabled us to look at the inside of the atrium, however, we could not see the thrombus (Figure 4). We then used an on-pump beating heart technique for as short a procedures as possible; a forefinger was inserted into the right atrium through the opened right atrial appendage, which was controlled by an appendage bursting suture. The thrombus was mobilized and floated up to the opening of the appendage, becoming visible at this stage, and preventing the atrial venous blood from coming outside when the bursting suture was released. The thrombus was extracted using ovum forceps through the right atrium opened appendage (Figures 5, 6). Immediately the HR went to 72 bpm (Figure 7). Post-operative, the patient was hemodynamic stable with no inotrope administered in the cardiac intensive care unit, and the patient was discharged home on the seventh day. A CT scan done one-week post-surgery showed absence of the previous mass (Figure 8). The histopathology report noted organized thrombus.

During follow up at 4, 8, and 12 weeks post-surgery, the patient was seen in the cardiology clinic where her BD was stable, with BP 130/80 mmHg, and HR was stable between 70–85 bpm. The patient was asymptomatic regarding positional dizziness and shortness of breath.

Discussion

Intra-cardiac thrombus (ICT) usually is located in the right side of the heart, and most commonly affects the right ventricle, but ICT located in the left ventricle or affecting both ventricles has also been described [1,9–12].

It is believed that the pathogenesis of the thrombotic formation in patients with BD is due to endothelial cell ischemia or disruption that leads to enhancement of platelet aggregation; other possible pathogenic mechanisms, which affect approximately 18% of cases, is due to the presence of anti-phospholipid antibodies [13–15].

ICT has also been frequently associated with superficial thrombophlebitis and deep venous thrombosis [3,16,17] or thrombosis of vena cava [9].

It has been speculated that pulmonary embolism or pulmonary infarction might have originated from deep vein thrombosis or right ventricular thrombi [12,18–20]. Pulmonary vascular manifestations are a result of in situ pulmonary pathology rather than embolization from systemic veins [1].

In our case, the complication of BD was diagnosed by echocardiography and CT scan followed by an intraoperative excisional biopsy removing the mechanical complication.

While conformation of the diagnosis is determined either at necropsy or after surgery, CT scan and MRI are considered an important tool in the diagnosis and assessment of a patient condition and might show vascular complications and give more information about lung parenchyma [21].

Although medical management has been associated with a better outcome, surgical removal has the advantage of providing material for histological examination [21].

Both anticoagulants and thrombolytic are considered first-line medical treatment of ICT [1], but in the presence of pulmonary aneurysms this therapy might lead to fatal hemoptysis, especially in bilateral and large aneurysms.

Right atrial thrombus is extremely rare, and our review the literature did not find reported case of right atrial thrombus that comprised the SA node causing positional bradycardia.

Conclusions

We conclude that thrombi in the right atrium of the heart can be present as an extremely rare case in BD, causing compression of SA node or a mechanical filling defect. Echocardiogram and CT scan are considered important tools in the diagnosis of these condition.

Cardiac surgical intervention should be considered in cases where medical treatment has failed to dissolve the thrombus, and surgery can be done safely using on-pump technique with cross clamp and cardiac arrest or on-pump technique with beating heart. This intervention can provide material for histological examination and confirmation of diagnosis.