Asian Cardiovasc Thorac Ann 2006;14:e93-e95
© 2006 Asia Publishing EXchange Ltd
Successful in situ Treatment of Infected Aortic Arch Prosthesis by Omental Wrapping
Yoshiharu Nishimura, MD,
Yoshitaka Okamura, MD,
Takeshi Hiramatsu, MD,
Hideaki Mori, MD,
Hiroki Hayashi, MD,
Shigeru Komori, MD
Department of Thoracic and Cardiovascular Surgerys, Wakayama Medical University, Wakayama, Japan
For reprint information contact: Yoshiharu Nishimura, MD Tel: 81 73 441 0615 Fax: 81 73 446 4761 Email: nishim-y{at}wakayama-med.ac.jp, Department of Thoracic and Cardiovascular Surgery, Wakayama Medical University, 811-1, Kimiidera, Wakayama 641-0012, Japan.
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ABSTRACT
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A 67-year-old man who underwent total aortic arch graft replacement with coronary artery bypass grafting developed postoperative Serratia mediastinitis. Re-operative debridement and irrigation were carried out. An infected aortic arch prosthesis was successfully treated by in situ disinfection followed by complete omental wrapping.
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INTRODUCTION
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Infection of an aortic arch prosthesis is a serious complication with high mortality. Removal of an infected aortic prosthesis and extra-anatomic bypass are almost impossible in such cases due to inherent anatomical complications. We report the successful treatment of this fatal complication following complete omental wrapping of an aortic arch prosthesis.
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CASE REPORT
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A 67-year-old man underwent aortic arch replacement and coronary artery bypass grafting due to distal arch aneurysm and old myocardial infarction. Aortic arch replacement was performed using a 26 mm branched arch graft (Hemashield Gold; Boston Scientific, NJ, USA) under deep hypothermic circulatory arrest with selective antegrade cerebral perfusion. The orifice of the left subclavian artery was not suitable for anastomosis. Therefore, the left axillary artery was exposed through infraclavicular incision and a branch of the prosthesis was bypassed through the left thoracic cavity to the left axillary artery. Saphenous vein grafts were used for aortocoronary bypass to the left anterior descending artery and posterolateral artery. The patient received perioperative cefazolin sodium for prophylaxis.
He remained well until postoperative day (POD) 4 when turbid effusion from the pericardial drainage tube and sternal instability were recognized. Leukocyte count was 19000 mUL–1 and C-reactive protein was 30.8 mg·dL–1.
Both pericardial drainage and left chest drainage culture grew Serratia marcescens, however blood culture was negative. As the patient did not need prolonged intensive care treatment it was not possible to determine if the cause of the infection by Serratia marcescens was attributed to postoperative management. Antibiotic therapy was broadened to imipenem + cilastatin sodium according to resistogram typing of the positive culture. Computed tomographic (CT) scan demonstrated pericardial effusion and left pleural effusion (Figure 1
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Figure 1. Contrast enhanced CT scan showing mediastinitis with periprosthetic collection surrounding the aortic arch prosthesis.
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On POD 7 surgical exploration of the mediastinum demonstrated sternal dehiscence and massive turbid effusion with which the aortic arch prosthesis was flooded. After copious irrigation with 3 liters of 5% povidone-iodine solution and debridement of the infected tissue around the prosthetic graft and pericardial cavity, the omentum was mobilized as a vascularized pedicle and transferred into the mediastinum up to the fossa jugularis. Omental wrapping of the heart, aortic arch prosthesis, and anastomotic sites was performed. We attempted to extirpate the branched graft to the left axillary artery in order to separate the mediastinal infection from the left pleural cavity, however, the left radial artery pressure diminished after clamping of the branched graft. Therefore, we trimmed the omental flap and pulled it through into the infraclavicular space across the pleural cavity to cover the branched graft. The omentum was fixed with multiple interrupted sutures after covering the heart and aortic arch prosthesis completely. There were no sign of osteomyelitis recognized in the sternum, and the sternum was refixed with sternal wires. Drainage tubes were placed in the retrosternal space and pericardial space. Antibiotic therapy consisted of ciprofloxacin.
On POD 23 a second re-fixation of the sternum was performed using a sternal band. At this surgery, investigations showed that the mediastinum was compactly covered by viable omentum. Irrigation with physiological saline through the irrigation-drainage system was continued for one additional week, and then stopped after negative findings of Serratia in the effusion drainage. The last CT scan demonstrated successful omental wrapping around the branched aortic arch prosthesis and the absence of any evidence indicating mediastinal fluid collection or false aneurysm (Figure 2). The patient was treated with intravenous ciprofloxacin for one month followed by a long course of oral levofloxacin after dischage. More than 6 months after the initial surgery, the patient remained well without any signs of infection.
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Figure 2. Contrast enhanced CT scan showing mediastinitis; (A) shows the irregular cavity around the branched graft was compactly filled by the omentum; (B) shows the main portion of the prosthesis wrapped by bulky omentum.
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DISCUSSION
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Infectious mediastinitis after thoracic aortic surgery is a potentially lethal complication and such an occurrence is of great concern to cardiovascular surgeons.1,2,3 Successful treatment of acute mediastinitis after aortic arch graft replacement, as achieved in our case, is very rare. In such a case, removal of the infected graft and replacement by another prosthetic graft or homograft, or extra-anatomical bypass are almost always impossible considering the anatomic or physiologic aspects of the patient. Therefore, prompt conservative therapy including irrigation and debridement of the mediastinal tissue and in situ disinfection of the aortic arch prosthesis by omental wrapping was performed.
A possible mechanism for the success of vascularized omental wrapping is provision of a higher oxygen supply to the infected tissue which intensifies the immunologic process and enhances antibiotic concentration. By filling the retrosternal space, the omentum absorbs wound discharge to remove the medium of bacterial growth.1 Moreover, the amorphous shape of the omentum eliminates the dead space and fills the irregular cavities of the branched graft.4
We consider that complete omental wrapping of the prosthesis was necessary. A branched arch prosthesis has a more complex structure than a straight graft, which is more commonly used for ascending aortic replacement. In our case, one of the branches of the arch prosthesis was bypassed to the left axillary artery through the left thoracic cavity. Therefore, we trimmed the omental flap to allow extension to the left infraclavicular portion of the branch of the prosthesis. In our case, it was advantageous that the blood culture at omental wrapping was negative and Serratia marcescens proved to be sensitive to the antibiotics administered. Moreover, the size of the omentum was sufficient to fill the space around the branched arch prosthesis.
In conclusion, by applying irrigation and debridement, prolonged anitibiotic disinfection and complete omental wrapping, we were able to salvage an infected aortic arch prosthesis. However, close surveillance for infection recurrence or formation of a false aneurysm remains mandatory.
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REFERENCES
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- Luciani N, Lapenna E, De Bonis M, Possati GF. Mediastinitis following graft replacement of the ascending aorta: conservative approach by omental transposition. Eur J Cardiothorac Surg 2001;20:418–20.[Abstract/Free Full Text]
- Mathes DW, Yaremchuk MJ, Isselbacher EM, Madsen JC. Successful in situ treatment of an infected ascending aortic graft. Ann Thorac Surg 2000;70:1410–12.[Abstract/Free Full Text]
- Coselli JS, Crawford ES, Williams TW Jr, Bradshaw MW, Wiemer DR, Harris RL, et al. Treatment of postoperative infection of ascending aorta and transverse aortic arch, including use of viable omentum and muscle flaps. Ann Thorac Surg 1990;50:868–81.[Abstract]
- Shrager JB, Wain JC, Wright CD, Donahue DM, Vlahakes GJ, Moncure AC, et al. Omentum is highly effective in the management of complex cardiothoracic surgical problems. J Thorac Cardiovasc Surg 2003;125:526–32.[Abstract/Free Full Text]
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ABSTRACT
INTRODUCTION
