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On-line version ISSN 1806-907X
Rev. Bras. Anestesiol. vol.58 no.1 Campinas Jan./Feb. 2008
Right atrial myxoma associated with acute cor pulmonale. Case report*
Mixoma de atrio derecho asociado a cor pulmonale agudo. Relato de caso
Michelle Nacur Lorentz, TSAI; Ektor Corrêa VrandecicII; Leonardo Ferber DrumondII; Raquel Reis Soares, TSAI
do Hospital Biocor
IICirurgião Cardiovascular do Hospital Biocor
OBJECTIVES: Atrial myxomas are the most common type of primary intracardiac
tumors. Although they are benign, it is recommended its immediate removal as
soon as the diagnosis is confirmed, since they are associated with tumor embolization
and their harmful consequences. The objective of this report was to present
the case of an intracardiac tumor of rare location (right atrium) that developed
intraoperative embolization and to alert anesthesiologists for the possibility
of this complication, besides discussing the anesthetic conduct.
CASE REPORT: A male patient, 42 years old, presented with a large mass in the right atrium, being scheduled for removal of the tumor. Anesthetic induction consisted of ethomidate, fentanyl and rocuronium bromide and it was maintained with isoflurane and fentanyl. Intraoperatively, the patient developed acute cor pulmonale secondary to tumor embolization, with the immediate institution of support measures and cardiopulmonary bypass. The remaining of the surgery was uneventful and the patient was discharged on the 7th postoperative day in good conditions.
CONCLUSIONS: Although intracardiac myxoma is a benign tumor, it can be associated with severe and even fatal complications. Knowledge of the disease is important for the proper management of those patients by the anesthesiologist, as well as to diagnose and treat possible intraoperative complications.
Key Words: COMPLICATIONS: pulmonary embolism, right ventricular outflow obstruction; Diseases: intracardiac myxoma.
Y OBJETIVOS: Los mixomas atriales son la forma más común de
tumor intracardiaco primario. A pesar de ser tumores de comportamiento benigno,
se recomienda que sean retirados en cuanto sean diagnosticados debido a la posibilidad
de embolización del tumor con sus nefastas consecuencias. El objetivo
de este relato de caso fue presentar un caso de tumor intracardiaco con localización
rara (intra-atrial derecho) que presentó embolización intraoperatoria
de parte del tumor y avisar a los anestesiólogos para la posibilidad
de esta complicación, además de discutir la conducta anestésica.
RELATO DEL CASO: Paciente del sexo masculino, 42 años, portador de gran masa en atrio derecho, sometido a la retirada del tumor. La inducción de la anestesia fue hecha con etomidato, fentanil y bromuro de rocuronio y el mantenimiento con isoflurano y fentanil. En el intraoperatorio el paciente presentó un cuadro de cor pulmonale agudo debido a la embolización de parte del tumor siendo realizadas medidas de soporte e iniciada rápidamente la circulación extra-corpórea. El resto de la operación transcurrió bien y el paciente tuvo alta al 7º día del postoperatorio en buenas condiciones.
CONCLUSIONES: A pesar del mixoma intracardiaco ser un tumor de características benignas, puede estar asociado a complicaciones graves y a veces fatales. El conocimiento de la enfermedad es importante para que el anestesiólogo pueda manosear adecuadamente esos pacientes, y diagnosticar y tratar las posibles complicaciones intraoperatorias.
Intracardiac masses are usually benign tumors that might be associated with significant morbidity and mortality, such as ventricular outflow obstruction, arrhythmias and embolization. Tumors in the right cardiac chambers can present with cardiac and extra-cardiac manifestations like congestive heart failure, syncope, fatigue, peripheral edema, jugular venous distention and ascitis 1. Although non-mobile myxomas do occur, its most important characteristic is the presence of a narrow, mobile and distensible pedicle 2. Due to this characteristic the tumor should be removed whenever it is diagnosed because it could lead to sudden death.
This is a 42-year old male patient, weighing 70 kg, with a history of mild hypertension who developed recent onset of dyspnea and peripheral edema. He was admitted to the hospital with atrial flutter with high ventricular response. During hospitalization he was managed clinically and a CT scan revealed the presence of a large mass in the right atrium. Tumor removal was indicated. Anesthetic induction consisted of fentanyl (10 µg.kg-1), rocuronium bromide (0.6 mg.kg-1) and ethomidate (0.3 µg.kg-1) and it was maintained with 1% to 2% isoflurane and additional doses of fentanyl for a total of 25 µg.kg-1. Monitoring consisted of electrocardiogram (ECG), pulse oximetry (SpO2), capnography (PETCO2), temperature, invasive blood pressure (IBP) and central venous pressure (CVP). Both anesthetic induction and the beginning of surgery were uneventful, with the patient hemodynamically stable, with a CVP of about 10 mmHg, SpO2 99% and PETCO2 30 mmHg. Thirty minutes after the beginning of the surgery, SpO2 suddenly dropped to 78%, PETCO2 to 9 mmHg, CVP increased to 18 mmHg and the patient became mildly hypotensive. At this moment, distention of the right ventricle (RV) was observed raising the possibility of a tumor embolization; ventilatory pattern was modified with an increase in respiratory rate to 16 rpm and the tidal volume (TV) was reduced to 7 mL.kg-1. Heparin was administered immediately for arterial and venous catheterization and early cardiopulmonary bypass (CPB) was instituted. When the right cardiac chambers were opened, two large tumoral masses were observed, one in the right atrium (which was fragmented) and the other had embolized to the RV, stopping in the pulmonary valve and causing ventricular outflow obstruction and acute cor pulmonale. Both tumors were removed and CPB and closure of the aorta lasted 58 and 37 minutes, respectively. Removal of the CPB was uneventful and the patient remained hemodynamically stable without the need of inotropic agents. He was extubated in the operating room after the surgery, when he had an adequate level of consciousness, normal temperature and adequate analgesia and hemostasis, was hemodynamically stable and could hold his head elevated for more than five seconds. Arterial blood gases just before extubation with FiO2 of 40% showed pO2= 130 mmHg and pCO2 = 38 mmHg. Arterial blood gases 10 minutes after extubation revealed pO2 = 98 mmHg and pCO2 = 42 mmHg. The patient was transferred to the ICU awake, calm, with 2 L.min-1 of oxygen through a nasal cannula and without any complaints of pain. The pathologic examination of the tumor revealed to be a myxoma. The patient was discharged from the hospital on the 7th postoperative day in good condition.
Intracardiac tumors are rare, with an incidence of 0.0017% to 0.19% in autopsies performed on random patients 3. Among primary cardiac tumors, myxomas are the most common. Approximately 85% of them are located in the left atrium 4, 15% in the right atrium, and intraventricular myxomas are even rarer (2% to 4%). Embolization caused by tumor fragments is a common and potentially fatal complication indicating the importance of an early diagnosis to avoid complications and lead to the cure of the patient since the surgical treatment is usually effective and recurrence is very rare. On the other hand, misdiagnosis or late diagnosis do occur because the initial clinical presentation is extra-cardiac and non-specific 5. Most cardiac tumors are benign, but can cause sudden death, both due to hemodynamic changes and conduction defects and, for those reasons, they are considered by some surgeons a medical emergency. The main particularity of the present case was the intraoperative embolization of part of tumor fragments, which, otherwise, would have probably led to the death of the patient. Karagounies and Sarsam 6 reported the case of a RV myxoma with intermittent right ventricular outflow obstruction; another case of RV myxoma with partial outflow obstruction was reported by Van der Heusen et al., and they suggested intraoperative monitoring with transesophageal echocardiogram 7.
Pulmonary embolism can cause profound hypoxemia as a consequence of two mechanisms: an increase in dead space and in shunting, which releases chemical mediators that cause bronchoconstriction and pulmonary vasoconstriction. The reduction in pulmonary vascular bed increases pulmonary vascular resistance, which can cause a reduction in cardiac output. When it happens, a ventilator pattern that improves hypoxemia and decreases RV post-load should be instituted. According to Vieillar-Baron et al., a tidal volume of 6 to 9 mL.kg-1, respiratory rate of 12 to 16 bpm, associated with positive end-expiratory pressure (PEEP) of 7 ± 3 cmH2O can improve ventilation without the need of hemodynamic support 8.
Acute cor pulmonale is defined as an increase in the RV resulting from disorders that affect pulmonary structure and/or function. However, isolated dilation of the RV does not mean ventricular dysfunction; it manifests in the presence of pressure overload in the RV. Based on the echocardiographic definition, massive pulmonary emboli and adult respiratory distress syndrome are the two main causes of acute cor pulmonale in adults 9. Occlusion of the pulmonary vascular bed can cause severe repercussions that depend on the affected area, capability of the RV to overcome the increase in post-load and pulmonary vasoconstriction. If a large area is occluded, it leads to pulmonary hypertension. This increase in post-load causes dilation of the RV, shifts the interventricular septum to the left and decreases left ventricular (LV) systolic volume, which can cause biventricular failure with reduction in blood pressure, perpetuating the disorder 10. In the present case, the patient developed mild hypotension (less than 10% of baseline values) and CPB was instituted immediately and, therefore, it was not necessary to use inotropic agents. Extubation in the operating room is another aspect that should be discussed, since CPB lasted 58 minutes and 25 µg.kg-1 of fentanyl were used; but since the patient awakened promptly at the end of the procedure and was ventilating properly, it was decided to carry out the extubation based on clinical and gasometric criteria.
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Dra. Michelle Nacur Lorentz
Rua Marquês de Maricá, 181/1.502 Santo Antônio
30350-070 Belo Horizonte, MG
Submitted em 5
de janeiro de 2007
Accepted para publicação em 25 de setembro de 2007
* Received from Biocor Instituto: Hospital de Doenças Cardiovasculares, Nova Lima, MG