Ann Thorac Surg 2006;81:383-385
© 2006 The Society of Thoracic Surgeons
How to do it
Wrapping of the Left Internal Thoracic Artery With an Expanded Polytetrafluoroethylene Membrane
Eric Bezon, MD
*
,
Yasser A. Maguid, MD,
Gildas Gueret, MD,
Jean N. Choplain, MD,
Ahmed A. Aziz, MD,
Jean A. Barra, MD
Department of Cardiovascular and Thoracic Surgery, C.H.U. La Cavale Blanche, Brest, France
Accepted for publication October 4, 2004.
* Address correspondence to Dr Bezon, Service de Chirurgie Cardiaque, Thoracique et Vasculaire, C.H.U. La Cavale Blanche, Brest, Cedex 29609 France. (Email: eric.bezon{at}chu-brest.fr).
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Abstract
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We describe the wrapping of the proximal segment of the left internal thoracic artery graft in a polytetrafluoroethylene membrane. Two groups of patients were compared (99 patients with wrapping, 70 patients as controls). There were no statistical differences between the two groups regarding the postoperative course. Three patients in the polytetrafluoroethylene group and 2 in the control group underwent reoperation for valve surgery. Exposure of the wrapped graft segment for clamping was safer and more rapid than in the control group.
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Introduction
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With improved long-term results of coronary artery bypass grafts and the widespread use of internal thoracic artery (ITA) grafts, a growing number of older patients are likely to require reoperative cardiac surgery in the setting of a patent ITA graft [1]. In reoperation, a patent ITA graft can be severely damaged [2]. The use of expanded polytetrafluoroethylene (PTFE) membrane reduces adhesions [3], but authors wrapped the ITA throughout its whole length with a long PTFE vascular prosthesis [3–5]. We propose a simpler approach by wrapping only the first 3 cm of the ITA pedicle with a PTFE membrane in order to locate and clamp the ITA in case of reoperation
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Technique
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The proximal segment of the left ITA pedicle is wrapped more than 3 cm in a PTFE membrane (Preclude Pericardial Membrane [WL Gore & Associates, Flagstaff, AZ]), sized 3 by 4 cm, just before closing the sternum (Fig 1). The patch is transformed in a tube with an edge-to-edge clipping, without tightening the ITA pedicle that should be freely mobile inside the tube. Then the PTFE tube is fixed to the surrounding mediastinal tissue in order to avoid further displacements. In case of bilateral ITA grafts, we use the "Y" procedure (reimplantation of the right ITA into the left in situ ITA) to avoid crossing the midline by the right ITA. In this case, only the proximal segment of the left ITA is wrapped, which is located above the reimplantation of the right ITA.
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Fig 1. Proximal wrapping of the left internal thoracic artery pedicle with a polytetrafluoroethylene membrane.
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From 1998 to 1999, 169 consecutive patients were divided in two groups and underwent coronary artery bypass grafts (group 1, 99 patients with wrapping; group 2, 70 patients as controls). Preoperative and intraoperative characteristics (Table 1) were similar in these groups.
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Results
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There were no significant differences between the two groups in the postoperative course (Table 2). The re-exploration for bleeding in group 1 was not related to the PTFE membrane that was left in place. The sternal wound infections in group 1 were treated without removing the PTFE membrane. Three-year freedom from recurrence of major cardiac events was 96% in group 1 and 97% in group 2.
In group 1, 3 patients underwent late reoperation (2 aortic valve replacements and 1 mitral valve repair at 6 months, 3 years, and 3 years of follow-up, respectively). In group 2, 2 patients underwent late reoperation (aortic valve replacements at 2 years and 3 years of follow-up).
In group 1, the localization and the surgical dissection of the PTFE tube were easy (Fig 2). There were slight adhesions between the PTFE membrane and the surrounding tissues, although the surgical dissection was guided by the stiffness and the white surgical aspect of the PTFE membrane. It took 10, 12, and 9 minutes, respectively in the first, second, and third patient, after re-sternotomy, to control the wrapped ITA, keeping in mind that we search the wrapped ITA before starting the dissection of the heart. The wrapped graft was clamped without removing the PTFE tube, just after clamping the aorta. Then continuous 20°C retrograde blood cardioplegia was delivered. At the end of the operation, the PTFE membrane was left in place. The postoperative follow-up was simple in the three cases. In group 2, the dissection was quite difficult due to the presence of severe adhesions. In one case the external muscular layers of the ITA wall were damaged, but fortunately without compromising the ITA patency, which was assessed by intraoperative Doppler. Twenty-nine minutes were required in the first case to control the ITA pedicle and 38 in the second case after re-sternotomy. The postoperative follow-up was simple.
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Comment
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In case of reoperation, temporary occlusion of the ITA graft reduces cardioplegia washout in the ITA grafted territory but requires graft dissection with the risk of ITA injury, which could be fatal [2]. Systemic deep hypothermia allows leaving the ITA unclamped [6], but deep hypothermia has potential deleterious side effects [7]. We have chosen to clamp the ITA to secure the retrograde cardioplegia, which is a good myocardial protection in reoperation.
In the reported studies, all the length of the ITA pedicle was passed inside a ringed PTFE vascular prosthesis before performing the distal coronary anastomoses [4, 5]. In case of bleeding with this technique, the hemostasis of the ITA pedicle is impossible without removing the vascular prosthesis. It is also difficult to eliminate twisting or kinking of the graft inside it. In our technique, proximal wrapping performed after protamine perfusion and safe hemostasis avoids these disadvantages. In addition, less synthetic material is implanted.
Our results show that the proximal wrapping does not increase surgical risks during the primary intervention and allows ITA clamping without tedious ITA dissection during the reoperation. Operative time is saved without risk of ITA injury.
For economic reasons, we use the proximal wrapping in patients who are younger than 60 years of age and when there is a foreseeable risk of late reoperation.
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References
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- Smith IV TW, Ferguson Jr B, Ryan T, Landolfo CK, Peterson ED. Should coronary artery bypass graft surgery patients with mild or moderate aortic stenosis undergo concomitant aortic valve replacement? A decision analysis approach to the surgical dilemma J Am Col Cardiol 2004;44:1241-1247.[Abstract/Free Full Text]
- Gillinov AM, Casselman FP, Lytle BW, et al. Injury to a patent left internal thoracic artery graft at coronary re-operation Ann Thorac Surg 1999;67:382-386.[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;8:650-655.[Medline]
- 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]
- Vaughn CC. Protective wrapping of the internal thoracic artery Ann Thorac Surg 1999;67:567-568.[Abstract/Free Full Text]
- Byrne John G, Karavas Alexandros N, Farzan F. Aortic valve surgery after previous coronary artery bypass grafting with functioning internal mammary artery grafts Ann Thorac Surg 2002;73:779-785.[Abstract/Free Full Text]
- Tonz M, Mihaljevic T, Von Segesser LK, et al. Normothermia versus hypothermia during cardiopulmonary bypass. A randomized controlled trial Ann Thorac Surg 1995;59:137-143.[Abstract/Free Full Text]
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Abstract
Introduction
