Ann Thorac Surg 2007;83:329-330
© 2007 The Society of Thoracic Surgeons
How To Do It
Cardiac Luxation to Facilitate Off-Pump Bilateral Lung Transplantation
Hester T. Visser, MD,
Michiel E. Erasmus, MD, PhD,
Tjark Ebels, MD, PhD*
Department of Cardiothoracic Surgery, University Medical Centre Groningen, University of Groningen, Groningen, the Netherlands
Accepted for publication May 15, 2006.
* Address correspondence to Dr Ebels, Department of Cardiothoracic Surgery, University Medical Centre Groningen, P. O. Box 30001, 9700 RB Groningen, the Netherlands (Email: t.ebels{at}thorax.umcg.nl).
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Abstract
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To facilitate access to the left hilum during off-pump bilateral lung transplantation we used the Xpose 4TM apical suction device (Guidant Corp., Indianapolis, IN), an off-pump coronary bypass device to luxate the heart out of the pericardium. The effects on circulation and possible myocardial injury were studied in retrospect. We found the device to provide us with an elegant and nondamaging method to visualize the left hilum.
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Introduction
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Bilateral lung transplantation is a routine procedure in which the lungs are transplanted sequentially, usually starting with the right lung. The right lung is almost always easily accessible through a bilateral thoracotomy without having to manipulate the heart for access to the pulmonary hilum. In contrast, to access the hilum of the left lung, particularly the pulmonary veins, the heart has to be lifted up and pulled rightward because of its position anterior to the left hilum. With this maneuver the circulation is easily compromised.
We have totally luxated the heart out of its pericardium using off-pump coronary surgery equipment to simplify access to the left hilum without compromise to the circulation.
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Technique
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The need for patient consent was waived by the chairperson of the Institutional Ethics Committee, because individual patients were not identified.
We started by transplanting the right lung in routine fashion through the right side of the routine bilateral clamshell thoracotomy. The pericardium is opened with an inverted T-shape incision to prevent any compression of the heart during the procedure. In the 6 study patients, before starting dissection of the left hilum, the apex of the heart was elevated anteriorly with a suction device designed for off pump coronary surgery (Xpose 4TM, Guidant Corp., Indianapolis, IN). This device is mounted on the sternal retractor for which it is designed, but in this case it was used for retraction of the transversely divided sternum (Acrobat, same company) (Fig 1). Rightward turning of the operating table further facilitates the procedure.
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Fig 1. Cardiac luxation using the Xpose device (Guidant Corp, Indianapolis, IN) giving a clear view of the left pulmonary hilum. (I = inferior; L = left; LAS = left atrial suture line; LPA = left pulmonary artery; LPV = left pulmonary vein; R = right; S = superior.)
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We used as much as 400 mm Hg of suction on the pressure regulator (Ohmeda Medical, Laurel, MD), depending on the weight and size of the heart, so that the heart could be luxated out of the pericardium with only the use of the Xpose. No additional sutures were used. We have calibrated the pressure regulator, which proved to be accurate within 2%.
To be sure about the negative pressure exerted by the suction cup of the device, we have measured the pressure existing within the cup at different regulator settings using an accurate manometer (QA-PT2H, Metron AS, Norway).
During the procedure, the systolic and diastolic arterial pressures were monitored invasively. Mean systolic and diastolic arterial pressures in our 6 patients were measured during cardiac luxation (ie, the period of transplanting the left lung) and were compared with the mean pressures during transplantation of the right lung. The difference in mean arterial pressures between the 2 periods was analyzed using the paired Student’s t test. We considered a drop of mean arterial pressure of 25% or more to be hemodynamically relevant.
After the procedure we measured the level of troponin I, a specific enzyme for myocardial injury. This measurement was done approximately 1 hour after the patient arrived in our thoracic intensive care unit. For comparison measurement of troponin I level was also performed in six matched patients who underwent bilateral lung transplantation without the use of the suction device. Differences in troponin I level between the two groups were analysed by the Mann-Whitney U test. This method was chosen because troponin I level was not normally distributed.
The actual negative pressure exerted on the epicardium in the cusp was 20% less than was set on the regulator. The source of the pressure difference was located between the stopcock that connects the braided tubing to the fluid collection container and the suction cup.
Cardiac luxation using the suction device was used in 6 of a total of 21 bilateral sequential lung transplantations performed from February 26 to November 17, 2005. The choice of technique was at the discretion of the surgeon. The six transplantations were done for cystic fibrosis (n = 2), other fibrosis (n = 2), and toxic inhalation trauma (n = 2). Two of the patients were children (ages 8 and 12 years, weighing 29 kg and 30 kg, respectively), and 4 patients were adults. In no case was cardiopulmonary bypass needed. Cardiac luxation lasted for a median of 77 minutes with a range of 46 to 175 minutes.
We found a difference in both systolic and diastolic arterial pressures between the period of transplantation of the right versus the left lung in 3 of 6 patients (p value < 0.05). In 1 patient there was a significant and relevant lowering of arterial pressures. In the other 2 patients there was a significant difference in arterial pressures that we considered not to be relevant (4%–14%).
Troponin I had been sampled in 5 of our 6 patients and had a mean value of 5.06 g/L (normal values: 0.00–0.04), indicating minor myocardial injury. Our control group consisted of 6 adult patients (ie, five bilateral lung transplantations and one unilateral transplantation of the right lung were performed in the same period of time without the use of cardiopulmonary bypass). Troponin I sampled in our control patients had a mean value of 4.00 g/L.
Comparing the troponin I levels of our two groups using the Mann-Whitney U test, we found a p value of 0.361, indicating that the difference in troponin I release between the two groups is likely due to chance.
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Comment
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Bilateral lung transplantation usually starts with transplantation of the right lung because this interferes in a minor way with the hemodynamic situation. For implantation of the left lung graft, the heart has to be manipulated so as to facilitate access to the left pulmonary hilum. In particular, access to the inferior pulmonary vein can be suboptimal in some cases. The operation is preferentially performed without cardiopulmonary bypass to keep the operation as simple as is possible, particularly considering the potential adverse effects such as hemorrhage, complement activation, endothelial damage, and pulmonary edema. This can make manipulation of the heart a delicate problem. With the use of the Xpose 4TM device we found a gentle way to luxate the heart outside the thoracic cavity, thus providing an easy access and clear view of the left pulmonary hilum (Fig 1). Hemodynamic compromise was minimal. Myocardial damage by the suction device was also minimal. The source of the troponin is probably located in the left atrial clamping and suture cuff [1].
When the hemodynamic situation does require usage of cardiopulmonary bypass, we have also used this method in 2 patients, in which it was our experience that this device exposes the left hilum more effectively and with less compromise of the cardiac function than a retractor or an assistant’s hand [2].
In conclusion, we found that the Xpose 4TM device provides us with an elegant and nondamaging manner to get a clear view of the left pulmonary hilum during bilateral lung transplantation.
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Acknowledgments
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We want to acknowledge technical support by Henk J. I. Janssen for execution of the measurements. We thank Inez J. den Hamer, MD for letting us include her patient in this series. We thank Fred A. de Geus for his calculations on hemodynamic pressures.
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References
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- Swaanenburg JC, Visser-van Brummen PJ, De Jongste MJ, Tiebosch AT. The content and distribution of troponin I, troponin T, myoglobin, alpha-hydroxybutyric acid dehydrogenase in the human heart Am J Clin Pathol 2001;115:770-777.[Abstract/Free Full Text]
- Sepic J, Wee JO, Soltesz EG, et al. Cardiac positioning using an apical suction device maintains beating heart hemodynamics Heart Surg Forum 2002;5:279-284.[Medline]
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Abstract
Introduction
