Right atrial myxoma associated with acute cor pulmonale: case report

Abstracts

JUSTIFICATIVA E OBJETIVOS: Os mixomas atriais são a forma mais comum de tumor intracardíaco primário. Apesar de serem tumores de comportamento benigno, recomenda-se que sejam retirados tão logo diagnosticados devido à possibilidade de embolização do tumor com suas nefastas conseqüências. O objetivo do presente relato foi apresentar um caso de tumor intracardíaco com localização rara (intra-atrial direito) que apresentou embolização intra-operatória de parte do tumor e alertar os anestesiologistas para a possibilidade dessa complicação, além de discutir a conduta anestésica. RELATO DO CASO: Paciente do sexo masculino, 42 anos, portador de grande massa em átrio direito, submetido à retirada do tumor. A indução da anestesia foi feita com etomidato, fentanil e brometo de rocurônio e a manutenção, com isoflurano e fentanil. No intra-operatório o paciente apresentou quadro de cor pulmonale agudo em virtude da embolização de parte do tumor, sendo realizadas medidas de suporte e iniciada rapidamente a circulação extracorpórea. O restante da operação transcorreu bem e o paciente recebeu alta no sétimo dia pós-operatório em boas condições. CONCLUSÕES: Apesar do mixoma intracardíaco ser um tumor de características benignas, ele pode estar associado a complicações graves e às vezes fatais. O conhecimento da doença é importante para que o anestesiologista possa manusear de modo adequado esses pacientes, bem como diagnosticar e tratar as possíveis complicações intra-operatórias.

COMPLICAÇÕES; COMPLICAÇÕES; DOENÇAS

CLINICAL REPORT

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, TSA^I; Ektor Corrêa Vrandecic^II; Leonardo Ferber Drumond^II; Raquel Reis Soares, TSA^I

^IAnestesiologista do Hospital Biocor

^IICirurgião Cardiovascular do Hospital Biocor

^{Correspondence to}

SUMMARY

BACKGROUND AND 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 7^th 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.

RESUMEN

JUSTIFICATIVA 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.

INTRODUCTION

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.

CASE REPORT

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 (P_ETCO₂), 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 P_ETCO₂ 30 mmHg. Thirty minutes after the beginning of the surgery, SpO₂ suddenly dropped to 78%, P_ETCO₂ 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 7^th postoperative day in good condition.

DISCUSSION

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.

REFERENCES

Submitted em 5 de janeiro de 2007

Accepted para publicação em 25 de setembro de 2007

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*

Received from Biocor Instituto: Hospital de Doenças Cardiovasculares, Nova Lima, MG

Publication Dates

• Publication in this collection
  17 Jan 2008
• Date of issue
  Feb 2008

History

• Accepted
  25 Sept 2007
• Received
  01 May 2007