Successful Surgical Treatment of a Right Atrial Myxoma Complicated by Pulmonary Embolism
A 76-year-old woman with hypertension was admitted to the hospital with complaints of chest pain and dyspnea. Arterial blood gas analysis revealed the following findings of hypoxemia and hypocapnia: PO2, 36.7 mmHg; and PCO2, 30.4 mmHg. The chest radiographs exhibited findings suggestive of pulmonary edema. The patient's cardiac enzyme values were: creatine kinase-MB, 105 ng/mL; and troponin I, 0.38 ng/mL. The B-type nitriuretic peptide test result was 64. A diagnosis of recent myocardial infarction was made based on the following electrocardiographic findings: T-wave inversions and Q waves in leads II and III and a VF, and T-wave inversions in leads V1 to V4. Transthoracic echocardiography revealed akinesia in the apex free wall of the right ventricle, moderate pulmonary hypertension (right ventricular systolic pressure [RVSP], 55 mmHg), and a 2.7×2.8 cm mobile mass in the free wall of the right atrium. Pulmonary computed tomography (CT) angiography revealed pulmonary emboli occluding the pulmonary arteries in the upper and lower lobes on both sides, and a suspicious intra-atrial cardiac tumor with pulmonary thromboembolism was revealed according to the radiologic findings (). We initiated systemic administration of heparin. To detect other possible causes of the pulmonary embolism, abdominal CT and tumor marker tests were performed, the results of which were all normal. The patient was diagnosed with pulmonary embolism due to the mass in the right atrium based on the result that the patient's D-dimer was <0.35. However, the patient refused surgical treatment. The patient was discharged from the hospital and received coumadin drug therapy. After 26 months, she was intubated due to severe dyspnea and was then referred to Ajou University Hospital. Transthoracic echocardiography revealed: 1) hypokinesia in the right ventricle, 2) a dilated right ventricle, 3) mild pulmonary hypertension, 4) a 3.5×2.8 cm mass in the free wall of the right atrium, which had grown compared to previous findings, and 5) tricuspid regurgitation.\nPulmonary CT angiography revealed emboli occluding the right pulmonary artery and segmental arteries in the upper, middle, and lower lobes with a right atrial mass. The radiological characteristics were similar to that of a previous study (an intra-atrial cardiac tumor with pulmonary thromboembolism) (). Pulmonary perfusion imaging showed decreased perfusion in the majority of the upper and lower right lobes, in part of the anterior segment of the left upper lobe, and in part of the superior and posterior basal segments of the left lower lobe (). Transesophageal echocardiography revealed a 4.8×2.6 cm hypermobile mass with multilobular heterogeneous echogenicity in the upper lateral aspect of the free wall of the right atrium, which was not affecting the blood flow in the superior vena cava, inferior vena cava, or tricuspid valves (). Coronary angiography showed findings of moderate coronary artery disease, which was treated with drug therapy alone. We decided to perform removal of the right pulmonary arterial emboli and the mass in the right atrium. The emboli in the left pulmonary artery decreased in size compared to the previous CT findings, and it was not considered a critical lesion because it was confined to the inferior lingular segmental artery. A standard sternotomy incision was made. The patient's body temperature was lowered to 23℃ (moderate hypothermia) through cardiopulmonary bypass, and then the myxoma with a 2 to 3 mm pedicle on the free wall of the right atrium was excised along with adjacent normal tissue. At 23℃, we opened the right pulmonary artery, which revealed that the myxoma segment was not adhered to the intima of the artery (). An embolus within the right pulmonary artery was removed en bloc in a bloodless surgical field (). After we confirmed that there were no further masses in the arteries supplying each segment, the right pulmonary artery and atrium were closed. Histopathological examination revealed that both the mass resected from the right atrium (4.3×3.5×3 cm) (, white arrow) and the embolus removed from the right pulmonary artery (7×2×1.5 cm) (, black arrow) were myxomas. On transthoracic echocardiography, we found that there were no residual masses. In addition, the size of the right atrium had decreased and the pulmonary artery pressure had slightly decreased to 35 mmHg. However, tricuspid regurgitation remained stationary (grade 2/4). Pulmonary CT angiography showed no further findings of pulmonary embolism. In the pulmonary perfusion imaging studies, the right lung had improved, but the left lung showed no changes. The patient was uneventfully discharged from the hospital on postoperative day 17. The patient is currently on out-patient follow-up without any significant symptoms. According to the echocardiography performed in December 2010, there was no evidence of pulmonary embolism, and the RVSP was 35 mmHg.