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Coronary artery bypass grafting with unanticipated fibrosing mediastinitis
Coronary Artery Bypass Grafting With Unanticipated Fibrosing Mediastinitis W. L. Holman, MD, G. K. Sethi, MD, and S. M. Scott, MD Department of Surgery, Duke University Medical Center, Durham, North Carolina, and Division of Cardiothoracic Surgery, The University of Alabama at Birmingham, Birmingham, Alabama
Coronary artery bypass grafting in the setting of superior vena caval obstruction due to unanticipated fibrosing mediastinitis is described. Intraoperative decisions regarding the management of this unusual patient are discussed. (Ann Thoruc Surg 1990;49:321-2)
A
lthough fibrosing mediastinitis is a nonmalignant condition, the proliferation of fibrous tissue within the mediastinum can impinge upon bronchi, cavae, pulmonary arteries, or the esophagus [14]. Histoplasma is considered to be the most common cause of fibrosing mediastinitis, although mycobacterial infections, sarcoidosis, nocardiosis, actinomycosis, aspergillosis, syphilis, and idiopathic systemic fibrosis [3-51 have also been implicated. The present case report describes the management of fibrosing mediastinitis and superior vena caval obstruction discovered at the time of elective coronary artery bypass grafting. A 57-year-old man with unstable class IV angina was referred to the Asheville VA Medical Center for consideration of coronary artery bypass grafting. The patient’s history dated to 1981 when he had an acute myocardial infarction. The patient later showed typical anginal symptoms that rapidly worsened over the 6 weeks before admission. Cardiac catheterization showed occlusion of the proximal left anterior descending coronary artery, 95% proximal stenosis of the right coronary artery, and 60% stenosis in the distal circumflex artery. His left ventricular ejection fraction was 78%. The patient also had chronic pulmonary disease. A right pulmonary nodule and surrounding fibrosis were apparent on chest roentgenogram (Fig 1). This finding had remained unchanged for several years. The arterial blood gas on room air showed a pH of 7.46, carbon dioxide tension of 30 mm Hg, and oxygen tension of 60 mm Hg. On pulmonary function testing, the forced vital capacity was 2.45 L and the forced expiratory volume in one second, 1.02 L. The remainder of the patient’s history, physical examination, and review of systems was Accepted for publication Aug 8, 1989. Address reprint requests to Dr Holman, Department of Surgery, University of Alabama at Birmingham, UAB Station, Birmingham, AL 35294. 0
1990 by The Society of Thoracic Surgeons
unremarkable. The patient did not have any symptoms suggesting superior vena caval obstruction. On physical examination, the patient had a ruddy complexion; however, pathological jugular venous distention was not present and the presence of superficial venous collateral vessels over the chest wall was masked by obesity. At operation, a right internal jugular sheath was placed without difficulty; however, a Swan-Ganz catheter could not be passed into the heart despite multiple attempts. Eventually, the catheter was passed from the femoral vein into the pulmonary artery. Measurements of venous pressure taken from the internal jugular catheter ranged from 3 to 6 mm Hg. Vigorous venous bleeding was encountered after the skin incision, and upon opening the pericardium, a dense fibrotic mass was seen constricting the superior vena cava. Multiple biopsy specimens of this tissue showed fibrosis and chronic inflammation. No tumor or organisms were seen on multiple sections or with special stains. There was no growth on subsequent culture of the material. The decision was made to proceed with coronary grafting. The pressure in the internal jugular vein was continuously monitored while the patient was perfused for 60 minutes at a temperature of 25°C. Saphenous vein grafts were constructed to the left anterior descending, first diagonal, and right coronary artery during a 22-minute period of cardioplegic arrest. The patient had an uneventful convalescence without neurological sequelae and has remained angina-free for more than 2 years.
Comment This patient had no symptoms of superior vena caval obstruction, and his chest wall collaterals were masked by obesity so that the presence of fibrosing mediastinitis compressing the superior vena cava was not diagnosed until the time of operation. Upon diagnosing the obstruction, an effort was made to determine the cause. Examination for fungal and mycobacterial organisms was included in the cultures, and histopathological examination included inspection of multiple sections and the use of a Gomori silver methenamine stain to identify Histoplusma cupsdatum. Malignancy and mycobacterial infection would require further therapy; however, antifungal drugs have no beneficial effect on established mediastinal fibrosis [6]. In managing a case similar to this, the venous pressure 0003-4975/90/@.50
322
CASE REPORT HOLMAN ET AL CABG IN FIBROSING MEDIASTINITIS
A
Ann Thorac Surg 1990;49:321-2
in the internal jugular system should be measured before cardiopulmonary bypass is initiated. Presumably, most asymptomatic patients will have well-established venous collaterals and low internal jugular pressure; however, the surgeon must be aware of the potential for impaired cerebral blood flow and brain edema if the patient is perfused with high cerebral venous pressure while in the supine position. If the internal jugular venous pressure is elevated, one can proceed with coronary grafting using an additional venous return catheter placed in the internal jugular vein through a separate cervical incision. However, if the grafting procedure could be safely deferred until a later date, further development of collaterals might make this additional cannulation unnecessary and would, at a minimum, allow optimal positioning and draping of the patient for internal jugular cannulation at the subsequent operation. Attempts to directly release the superior vena cava from fibrotic encasement are strongly discouraged, although the caseous contents of a large granuloma compressing the cava can be safely evacuated [5].Other maneuvers to help in maintaining a low internal jugular pressure during bypass would include raising the patient's upper body or conducting perfusion at a sufficiently low temperature to safely allow low perfusion flow during bypass. If the venous pressure is elevated, a decision regarding permanent bypass of the obstructed superior vena cava must be made. The spiral saphenous vein graft technique as described by Doty [7] is recommended for such a bypass based on previously published results [2, 3, 81. An aggressive surgical attitude to coronary grafting in the setting of mediastinal fibrosis and superior venal caval obstruction is recommended based not only on the successful outcome in this 1 patient but also on the possible need for other operations in the future [l,41.
References
B Fig 1 . (A) Preoperative chest roentgenogram showing the right pulm o n a y nodule with surrounding fibrosis. ( B ) Detail of right lung mass and surrounding fibrosis.
1. Scully RE, Mark EJ, McNeely WF, McNeely BU. Case records of the Massachusetts General Hospital: Case 6-1989. N Engl J Med 1989;320:380-9. 2. Miller RE, Sullivan FJ. Superior vena caval obstruction secondary to fibrosing mediastinitis. Ann Thorac Surg 1973;15: 48S92. 3. Mitchell IM, Saunders NR, Maher 0, Lennox SC, Walker DR. Surgical treatment of idiopathic mediastinal fibrosis: report of five cases. Thorax 1986;41:21&4. 4. Herse 8, Dalichau H, Mennicken U. Idiopathic mediastinal fibrosis: a case report on its surgical treatment. Thorac Cardiovasc Surg 1984;3235-40. 5. Scott SM, Sethi GK, Takaro T, Enright TJ. Thoracic surgical infections. In: Howard RJ, Simmons RL, eds. Surgical infectious diseases. Nonvalk, Connecticut: Appleton and Lange, 1988: 6. Gryboski WA, Crutcher RR, Holloway JB, Mayo, ' l Segnitz RH, Eiseman B. Surgical aspects of histoplasmosis. Arch Surg 1963;87:590-9. 7. Doty DB. Bypass of the superior vena cava. J Thorac Cardiovasc Surg 1982;83:32&38. 8. Garrett HE, Roper CL. Surgical intervention in histoplasmosis. Ann Thorac Surg 1986;42:711-22.
Coronary artery bypass grafting in the setting of superior vena caval obstruction due to unanticipated fibrosing mediastinitis is described. Intraoperative decisions regarding the management of this unusual patient are discussed. (Ann Thoruc Surg 1990;49:321-2)
A
lthough fibrosing mediastinitis is a nonmalignant condition, the proliferation of fibrous tissue within the mediastinum can impinge upon bronchi, cavae, pulmonary arteries, or the esophagus [14]. Histoplasma is considered to be the most common cause of fibrosing mediastinitis, although mycobacterial infections, sarcoidosis, nocardiosis, actinomycosis, aspergillosis, syphilis, and idiopathic systemic fibrosis [3-51 have also been implicated. The present case report describes the management of fibrosing mediastinitis and superior vena caval obstruction discovered at the time of elective coronary artery bypass grafting. A 57-year-old man with unstable class IV angina was referred to the Asheville VA Medical Center for consideration of coronary artery bypass grafting. The patient’s history dated to 1981 when he had an acute myocardial infarction. The patient later showed typical anginal symptoms that rapidly worsened over the 6 weeks before admission. Cardiac catheterization showed occlusion of the proximal left anterior descending coronary artery, 95% proximal stenosis of the right coronary artery, and 60% stenosis in the distal circumflex artery. His left ventricular ejection fraction was 78%. The patient also had chronic pulmonary disease. A right pulmonary nodule and surrounding fibrosis were apparent on chest roentgenogram (Fig 1). This finding had remained unchanged for several years. The arterial blood gas on room air showed a pH of 7.46, carbon dioxide tension of 30 mm Hg, and oxygen tension of 60 mm Hg. On pulmonary function testing, the forced vital capacity was 2.45 L and the forced expiratory volume in one second, 1.02 L. The remainder of the patient’s history, physical examination, and review of systems was Accepted for publication Aug 8, 1989. Address reprint requests to Dr Holman, Department of Surgery, University of Alabama at Birmingham, UAB Station, Birmingham, AL 35294. 0
1990 by The Society of Thoracic Surgeons
unremarkable. The patient did not have any symptoms suggesting superior vena caval obstruction. On physical examination, the patient had a ruddy complexion; however, pathological jugular venous distention was not present and the presence of superficial venous collateral vessels over the chest wall was masked by obesity. At operation, a right internal jugular sheath was placed without difficulty; however, a Swan-Ganz catheter could not be passed into the heart despite multiple attempts. Eventually, the catheter was passed from the femoral vein into the pulmonary artery. Measurements of venous pressure taken from the internal jugular catheter ranged from 3 to 6 mm Hg. Vigorous venous bleeding was encountered after the skin incision, and upon opening the pericardium, a dense fibrotic mass was seen constricting the superior vena cava. Multiple biopsy specimens of this tissue showed fibrosis and chronic inflammation. No tumor or organisms were seen on multiple sections or with special stains. There was no growth on subsequent culture of the material. The decision was made to proceed with coronary grafting. The pressure in the internal jugular vein was continuously monitored while the patient was perfused for 60 minutes at a temperature of 25°C. Saphenous vein grafts were constructed to the left anterior descending, first diagonal, and right coronary artery during a 22-minute period of cardioplegic arrest. The patient had an uneventful convalescence without neurological sequelae and has remained angina-free for more than 2 years.
Comment This patient had no symptoms of superior vena caval obstruction, and his chest wall collaterals were masked by obesity so that the presence of fibrosing mediastinitis compressing the superior vena cava was not diagnosed until the time of operation. Upon diagnosing the obstruction, an effort was made to determine the cause. Examination for fungal and mycobacterial organisms was included in the cultures, and histopathological examination included inspection of multiple sections and the use of a Gomori silver methenamine stain to identify Histoplusma cupsdatum. Malignancy and mycobacterial infection would require further therapy; however, antifungal drugs have no beneficial effect on established mediastinal fibrosis [6]. In managing a case similar to this, the venous pressure 0003-4975/90/@.50
322
CASE REPORT HOLMAN ET AL CABG IN FIBROSING MEDIASTINITIS
A
Ann Thorac Surg 1990;49:321-2
in the internal jugular system should be measured before cardiopulmonary bypass is initiated. Presumably, most asymptomatic patients will have well-established venous collaterals and low internal jugular pressure; however, the surgeon must be aware of the potential for impaired cerebral blood flow and brain edema if the patient is perfused with high cerebral venous pressure while in the supine position. If the internal jugular venous pressure is elevated, one can proceed with coronary grafting using an additional venous return catheter placed in the internal jugular vein through a separate cervical incision. However, if the grafting procedure could be safely deferred until a later date, further development of collaterals might make this additional cannulation unnecessary and would, at a minimum, allow optimal positioning and draping of the patient for internal jugular cannulation at the subsequent operation. Attempts to directly release the superior vena cava from fibrotic encasement are strongly discouraged, although the caseous contents of a large granuloma compressing the cava can be safely evacuated [5].Other maneuvers to help in maintaining a low internal jugular pressure during bypass would include raising the patient's upper body or conducting perfusion at a sufficiently low temperature to safely allow low perfusion flow during bypass. If the venous pressure is elevated, a decision regarding permanent bypass of the obstructed superior vena cava must be made. The spiral saphenous vein graft technique as described by Doty [7] is recommended for such a bypass based on previously published results [2, 3, 81. An aggressive surgical attitude to coronary grafting in the setting of mediastinal fibrosis and superior venal caval obstruction is recommended based not only on the successful outcome in this 1 patient but also on the possible need for other operations in the future [l,41.
References
B Fig 1 . (A) Preoperative chest roentgenogram showing the right pulm o n a y nodule with surrounding fibrosis. ( B ) Detail of right lung mass and surrounding fibrosis.
1. Scully RE, Mark EJ, McNeely WF, McNeely BU. Case records of the Massachusetts General Hospital: Case 6-1989. N Engl J Med 1989;320:380-9. 2. Miller RE, Sullivan FJ. Superior vena caval obstruction secondary to fibrosing mediastinitis. Ann Thorac Surg 1973;15: 48S92. 3. Mitchell IM, Saunders NR, Maher 0, Lennox SC, Walker DR. Surgical treatment of idiopathic mediastinal fibrosis: report of five cases. Thorax 1986;41:21&4. 4. Herse 8, Dalichau H, Mennicken U. Idiopathic mediastinal fibrosis: a case report on its surgical treatment. Thorac Cardiovasc Surg 1984;3235-40. 5. Scott SM, Sethi GK, Takaro T, Enright TJ. Thoracic surgical infections. In: Howard RJ, Simmons RL, eds. Surgical infectious diseases. Nonvalk, Connecticut: Appleton and Lange, 1988: 6. Gryboski WA, Crutcher RR, Holloway JB, Mayo, ' l Segnitz RH, Eiseman B. Surgical aspects of histoplasmosis. Arch Surg 1963;87:590-9. 7. Doty DB. Bypass of the superior vena cava. J Thorac Cardiovasc Surg 1982;83:32&38. 8. Garrett HE, Roper CL. Surgical intervention in histoplasmosis. Ann Thorac Surg 1986;42:711-22.