Interactive Cardiovascular and Thoracic Surgery 3:516-518(2004)
© 2004 European Association of Cardio-Thoracic Surgery
Does wrapping of the right internal thoracic artery to the left anterior descending artery always protect?
Calin Vicola,*,
Sandra Eiferta,
Bernd J. Winterspergerb and
Bruno Reicharta
a Department of Cardiac Surgery, Großhadern Medical Center, Marchioninistr. 15, Munich 81377, Germany
b Institute for Diagnostic Radiology of the Ludwig-Maximilians-University Munich, Großhadern Medical Center, Marchioninistr. 15, 81377 Munich, Germany
* Corresponding author. Address: Klinik und Poliklinik für Herzchirurgie, Klinikum Großhadern der Ludwig-Maximilians-Universität Mänchen, Marchioninistr. 15, Munich 81377, Germany. Tel.: +49-89-7095-2358
cvicol{at}helios.med.uni-muenchen.de
Received November 25, 2003;
received in revised form February 25, 2004;
accepted March 15, 2004
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Abstract
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We report about a 72-year-old woman with coronary artery disease. Surgical revascularization was performed using three grafts. One of them was the right internal thoracic artery (RITA) to left anterior descending. This graft was covered by a PRECLUDE® IMA Sleeve. Wound healing was impaired and became to a chronic sternal osteomyelitis and mediastinitis. Thirty-three months after the primary operation, the PRECLUDE® IMA Sleeve was explanted, the sternum was partially resected and the resulting cavity reconstructed with an omentum flap. During that operation, the RITA bypass was damaged. Interposition of a venous segment was necessary to reconstitute the graft.
Key Words: Internal thoracic artery; Wrapping; Expanded polytetrafluoroethylene; Redo
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1. Introduction
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Multiple arterial conduits, especially both internal thoracic arteries (ITAs) combined, lead to better long-term results after myocardial revascularization [1]. However, the injury of a non-occluded ITA bypass increases the morbidity and early mortality in the frame of reoperation [2]. Especially prone to such events is the retrosternal right internal thoracic artery (RITA) to left anterior descending (LAD). To prevent lesion of this bypass graft during reoperation, it has been recommended to wrap the RITA with an expanded polytetrafluoroethylene sleeve [3]. We report our experience during the removal of a PRECLUDE® IMA Sleeve (W.L. Gore and Associates, Inc., Flagstaff, AZ, USA) 33 months after implantation.
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2. Case report
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A 72-year-old female with coronary artery three vessel disease and New York Heart Association functional class IV underwent myocardial revascularization outside of our department. Due to severe varicose veins, total arterial revascularization was carried out. Surgery consisted of RITA to LAD, left internal thoracic artery (LITA) to first marginal branch and left radial artery to right coronary artery. To protect the retrosternal part, RITA was wrapped by a 10 cm long PRECLUDE® IMA Sleeve. The intra- and postoperative course was uneventful. The patient was discharged 10 days after surgery.
The patient had to be rehospitalized two months later with a dehiscent sternal wound. Bacteriology showed Oxacillin-(Methicillin) resistent Staphylococcus aureus (MRSA). The antibiotic treatment consisted of Vancomycine, Rifampicine und Fosfomycine. Two sternal steel wires were removed and the wound closed. Two weeks later, a new revision for recurrent dehiscence was necessary. Drainage for rinsing and suction was installed. At discharge three weeks later the wound was intact.
Eight months later, the patient suffered from a fistula in the medial sternal scar. The fistula was resected and all remaining steel wires were removed. The wound smear demonstrated MRSA again. Vancomycine and Rifampicine were given again. The wound healing was uneventful and the patient could be discharged after two weeks.
One year later, the patient was readmitted to the hospital. This time she had a fistula in the area of the upper third of the sternal scar. Bacteriology contained MRSA. Beside an antibiotic treatment, newly built fistula was excised. The intervention remained unsuccessful.
At this time, the patient was admitted to our department. Decision was taken to carry out an extended resection including removal of PRECLUDE® IMA Sleeve, sternal resection and omentum plasty. To get precise knowledge, angiography was carried out showing patent grafts. An electron beam computed tomography demonstrated accurately the course of wrapped RITA bypass. The graft started at a heights of the right sterno-clavicular joint, followed by a retrosternal course from right to left and up to downwards, respectively (Fig. 1). Resternotomy was uneventful. The PRECLUDE® IMA Sleeve was identified directly behind the sternum. In this region we found an abscess cavity directly connected to the cutaneous fistula (Fig. 2). During explantation of the sleeve despite meticulous dissection, RITA was injured. Extracorporeal circulation was established via femoral vessels. The sleeve was completely resected. A 4 cm long RITA segment had to be sacrificed. A venous interponate was anastomosed end-to-end to restore the graft. The fistula and large parts of the manubrium and corpus sterni were resected. The resulting cavity was filled with an omentum flap. The postoperative course was uneventful and the wound healing was normal. The patient could be discharged after two weeks. The wound is intact 11 months after the operation.
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Fig. 1 Electron beam computed tomography at the level of the upper mediastinum: Manubrium sterni with substantial defects and signs of osteomyelitis. Directly retrosternal PRECLUDE® IMA Sleeve walled by inflammatory tissue.
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Fig. 2 Retrosternally located PRECLUDE® IMA Sleeve, directly connected to the superficial cutaneous fistula. The scissors is showing the way of the fistula from skin to sleeve.
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3. Comment
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LITA to LAD is the gold standard of myocardial revascularization. Operative results in multi vessel coronary artery disease improve by use of both internal thoracic arteries [1]. Most frequently ITAs are deployed in situ or as T-shaped composite graft. Three combinations are possible using ITAs in situ: (1) guide the RITA through the transverse sinus and connect it to a posterior wall vessel and connect LITA to LAD; (2) connect RITA to the right coronary artery and LITA to LAD and (3) connect RITA to LAD and LITA to a posterior wall vessel. Last opportunity has two disadvantages. First, the excellent results of LITA to LAD are disregarded and second, there is a considerable risk of injury to the RITA during reoperation. The Cleveland Clinic group could demonstrate that retrosternal LITA is leading to a higher incidence of myocardial infarction and higher mortality through damage in the frame of reoperation compared to conduits passing through a pericardial incision lateral to the pulmonary artery and distal to the sternotomy [2]. To prevent injury to the retrosternally located RITA, a synthetic cover sleeve was taken into consideration. For that reason, Zacharias et al. utilized a 12 mm ring enhanced expanded polytetrafluoroethylene vascular prosthesis in 28 patients [3]. The protective effect of a coverage by means of a Gore-Tex surgical membrane was proven in animal experiments with promising results by Zehr [4]. Vicol reported his experience with the PRECLUDE® IMA Sleeve for wrapping LITA to LAD and showed evidence that wrapping of LITA bypass did not evoke complications [5]. After careful review of the literature, our report is the first case of reoperation long time after implantation of a PRECLUDE® IMA Sleeve. The exposure of the wrapped graft led to a RITA lesion despite careful preparation. Already in 1997 Zacharias doubted the protective potential of PRECLUDE® IMA Sleeve and wanted to supply arguments in favour of a stronger material such as ring enhanced vascular prosthesis [6]. Another aspect worth discussing is the risk of infection after PRECLUDE® IMA Sleeve had been applied to a RITA with direct retrosternal course. Experience has shown, the more superficial a foreign material is related to the operative access, the higher is the risk of infection. In our case, we postulate an early contamination of the sleeve, which could be completely excluded only by removal.
In this particular case, the implantation of PRECLUDE® IMA Sleeve for protection of RITA to LAD led from a superficial wound healing disorder to chronic sternal osteomyelitis and mediastinitis. We did not prove in our patient the protective effect of wrapping the bypass graft such as provided by PRECLUDE® IMA Sleeve in reoperations. In our opinion, that preference to supply LAD should be given to LITA when quality of ITAs is comparable.
doi:10.1016/j.icvts.2004.03.009
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References
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- Gillinov AM, Casselman FP, Lytle BW, Blackstone EH, Parsons EM, Loop FD, Cosgrove DM 3rd. Injury to a patent left internal thoracic artery graft at coronary reoperation. Ann Thorac Surg. 1999;67:382–386[Abstract/Free Full Text]
- Zacharias A. Protection of the right internal mammary artery in the retrosternal position with stented grafts. Ann Thorac Surg. 1995;60:1826–1828[Abstract/Free Full Text]
- Zehr KJ, Lee PC, Poston RS, Gillinov AM, Hruban RH, Cameron DE. Protection of the internal mammary artery pedicle with polytetrafluoroethylene membrane. J Card Surg. 1993;8(6):650–655[Medline]
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- Zacharias A. Reply to Zehr KJ. Ann Thorac Surg. 1997;63:297–298[Free Full Text]
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Abstract
1. Introduction