CASE REPORT. Mycotic Aneurysm of Ascending Aorta Due to Sarcina Lutea. G. A. Lopez, M.D., and A. R. C. Dobell, M.D.

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1 CASE REPORT Mycotic Aneurysm of Ascending Aorta Due to Sarcina Lutea G. A. Lopez, M.D., and A. R. C. Dobell, M.D. ABSTRACT A patient developed a mycotic aneurysm of the aortic suture line after aortic valvulotomy. The aneurysm was resected, but it recurred; it was again resected, but with more debridement of the neighboring aortic tissue. The technical steps to avoid premature rupture during sternotomy and dissection of the aorta are described. To our knowledge, this is the first clinical infection with Sarcina lutea, formerly not considered to be a pathogen. A mycotic aneurysm presents a formidable problem wherever it is located because successful treatment requires both eradication of the aneurysm and elimination of the infection. Repair generally involves the use of prosthetic fabric and always involves the use of sutures, so there is a strong possibility of recurrent infection and aneurysm after operation. When such aneurysms involve the ascending aorta, there are additional technical hazards related to the possibility of premature rupture during sternotomy or during opening of the pericardium. This case report presents a technique which enabled us to avoid premature rupture in repairing a mycotic aneurysm. It also documents, apparently for the first time, a life-threatening infection by Sarcina Zutea. A 12-year-old boy underwent aortic valvulotomy for congenital valvular stenosis. The aortic valve was exposed through a transverse incision in the aorta, and the incision was repaired with a running suture of fine silk. He received ampicillin prophylactically for six days and was dismissed from the hospital eight days after operation without apparent complications. He was readmitted one month after operation with persistent fever, nausea, and occasional vomiting and diarrhea, having been treated at home with penicillin for seven days without improvement. In the hospital, penicillin was stopped and seven blood cultures were drawn over the next few From the Department of Cardiovascular Surgery, The Montreal Children s Hospital, Montreal, Que., Canada. Accepted for publication June 21, Address reprint requests to Dr. Dobell, The Montreal Children s Hospital, 2300 Tupper St., Montreal 108, Que., Canada. VOL. 13, NO. 6, JUNE,

2 LOPEZ AND DOBELL days. In two weeks the blood cultures were growing S. Zutea, which was considered to be a contaminant. Bacterial endocarditis was nevertheless considered to be the diagnosis, and intravenous penicillin, 2 1 million units daily, was begun together with 250 mg. of streptomycin twice daily. Three weeks later the fever had not subsided, and penicillin was replaced with erythromycin, 250 mg. every four hours. A month after readmission three blood cultures were growing S. Zutea, and this organism was accepted as the cause of the endocarditis. The original sensitivity studies showed that the S. Zutea was susceptible to both penicillin and erythromycin, although the dosage required would be much higher than normal therapeutic levels. Chest radiographs were taken regularly, and two months after admission an aneurysm arising from the right anterior aspect of the ascending aorta was suspected (Fig. 1). This was confirmed by tomography and fluoroscopy. Three months after the aortic valvulotomy, operation was again performed with the diagnosis of a mycotic aneurysm of the suture line in the ascending aorta (Fig. 2). The patient's left external iliac artery and vein were cannulated, and he was attached to a pump-oxygenator by these conduits. The venous cannula, 6 mm. in internal diameter, was passed up to the level of the diaphragm. The blood temperature was reduced to 25 C. with a heat exchanger. When the esophageal temperature was 27"C., the previously made sternotomy was reincised and the sternal edges were separated. We had planned to institute total circulatory arrest by stopping the pumpoxygenator if hemorrhage occurred. However, the sternal edges could be separated and the right atrium exposed without opening the aneurysm. A second venous drainage line was passed into the atrium. Blood temperature was further reduced until ventricular fibrillation occurred. The extracorporeal flow was then stopped, and the aneurysm, which measured 6 cm. in diameter, was incised. The base of the aneurysm was the suture line closing the aortotomy, which was completely open. The silk suture was removed and sent for bacteriological culture. The margins of the aorta were trimmed, FIG. 1. Chest radiograph showing the mycotic aneurysm three months after aortic valvulotomy. 608 THE ANNALS OF THORACIC SURGERY

3 CASE REPORT: Mycotic Aneurysm of Aorta OR1 GI NAL OPERATIVE RESULT FZG. 2. (Above) Representation of the result following aortic valuulotonzy. (Below) The infected aneurysm filling the retrosternal space. and most of the wall of the false aneurysm was removed. The aorta above the aneurysm was isolated and cross-clamped, and body perfusion was reinstituted. The aortic defect was repaired with a single running suture of Mersilene, and the operation was terminated uneventfully. Specimens of the silk suture and the aortic wall both showed a heavy growth of S. Zutea. Penicillin was given intravenously in a dose of 20 million units per day, but the patient continued to have a daily fever. One month after resection of the mycotic aneurysm the radiological signs of an aneurysm reappeared. Operation was again performed. The same technique was employed, with peripheral cannulations and hypothermia induced by bloodstream cooling. Again inadvertent opening of the aneurysm was avoided, and it was incised under conditions of total circulatory arrest. This time the entire aneurysm was excised together with 1 cm. of aorta on each side of the incision (Fig. 3). A large patch of woven Teflon fabric was sutured into the aortic defect with Mersilene sutures. Hemostasis required considerable time, but when it had been achieved the operation was terminated successfully. A blood culture obtained just before this operation grew S. Zuteu, as did the aortic wall removed at operation. Postoperatively vancomycin was given intravenously in a dosage of 1,200 mg. daily. In addition, 500 mg. of VOL. 13, NO. 6, JUNE,

4 LOPEZ AND DOBELL WITH ANEURYSM SCAR TISSUE REMOVED FROM AORTA WINDOW CUT FIG. 3. The second reoperation is depicted. The same technique was used as in the first reoperation, but debridement was radical and a patch of woven Teflon was interposed to fill the aortic defect. kanamycin was given daily. The latter was discontinued after four days because sensitivity studies indicated that the vancomycin would suffice. The patient continued to have a daily fever spike for four weeks. Chloramphenicol, 2,400 mg. daily, was given for four days, but the white blood cell count was low (3,600) and, since we were concerned about the toxicity of both chloramphenicol and vancomycin, we decided to stop all antibiotics. His temperature came down to normal immediately, and his white blood count and hemoglobin returned to normal. The sedimentation rate dropped from 40 to 20 mm. per hour. He was released from the hospital six weeks after the second aneurysm resection. A week later he was readmitted with fever, and a left thoracocentesis yielded sterile fluid. His temperature returned to normal, and after observation for ten days he was discharged home. His sedimentation rate at that time was 24 mm. per hour, the white blood cell count was 6,700 per cubic millimeter with a normal differential count, and the hemoglobin was 12.2 gm. per 100 milliliters. Blood cultures were repeatedly negative. Two years after the last operation he remains asymptomatic and is actively participating in sports at school. Comment The technique used in the management of this patient has been thoroughly reviewed by Lillehei and his associates [31. Like them and others 610 THE ANNALS OF THORACIC SURGERY

5 CASE REPORT: Mycotic Aneurysm of Aorta [l, 2, 41, we have used total circulatory arrest in taking down aorta-to-pulmonary artery anastomoses before total correction of tetralogy of Fallot and in certain stages of repair of other forms of cyanotic heart disease. The case reported here is similar in many respects to the dramatic first case of Lillehei and associates. Total circulatory arrest is essential for two reasons. The first is to have a manageable situation should the aneurysm of the ascending aorta rupture in dividing and separating the sternum. The second is to allow the aneurysm to be opened and decompressed before isolating the aorta above it. Conventional bypass would require such isolation in order that the aorta could be cross-clamped proximal to the innominate artery; such a dissection would be extremely tedious at best and often impossible because of the overlying aneurysm. The recurrence of infection in the suture line was undoubtedly due to inadequate debridement the first time around. On that occasion we avoided the use of a prosthetic patch to repair the aortic defect in the belief that such a patch would almost certainly become infected. On the contrary, adequate removal of infected tissue at the second operation permitted healing without infection despite the interposition of a sizeable patch of fabric. Sarcina Zutea is a gram-positive micrococcus found in air, soil, and water. Under favorable conditions cell division occurs in three planes, so that cubical pockets are formed [5]. The bacterium is considered nonpathogenic to man and animals and is so notoriously penicillin sensitive that cultures are often used to evaluate the potency of penicillin. We have not found a previous report incriminating S. Zutea as a cause of disease in man. Possibly our routine short-term preoperative antibiotic regimen permitted the development of a penicillin-resistant strain, although the prophylactic antibiotic (ampicillin) was given in therapeutic doses. The penicillin given blindly to treat the patient s fever when he was home was obviously ineffective and may have been harmful. References 1. Gross, R. E., Bernhard, W. F., and Litwin, S. B. Closure of Potts anastomoses in the total repair of tetralogy of Fallot. J. Thorac. Cardiovasc. Surg. 57:72, Kirklin, J. W., Dawson, B., Devloo, R. A., and Theye, R. A. Open intracardiac operations: Use of circulatory arrest during hypothermia induced by blood cooling. Ann. Surg. 154:769, Lillehei, C. W., Todd, D. B., Jr., Levy, M. J., and Ellis, R. J. Partial cardiopulmonary bypass, hypothermia, and total circulatory arrest: A life-saving technique for ruptured aortic aneurysms, ruptured left ventricle and other complicated cardiac pathology. J. Thorac. Cardiovasc. Surg. 58: 530, Sealy, W. C., Brown, I. W., and Young, W. C., Jr. A report of the use of both extracorporeal circulation and hypothermia for open heart surgery. Ann. Surg. 147:603, Wilson, G. S., and Miles, A. A. Topley and Wilson s Principles of Bacteriology and Zrnrnunity (3d ed.). London: Arnold, P VOL. 13, NO. 6, JUNE,