Ann Thorac Surg 2009;88:e69-e71. doi:10.1016/j.athoracsur.2009.09.024
© 2009 The Society of Thoracic Surgeons
How To Do It
Staged Repair of a Chronic Dissecting Aneurysm With the Two Elephant Trunks Technique
Chul-Hyun Park, MD*,
Chang-Hu Choi, MD,
Yang-Bin Jeon, MD,
Jae-Ik Lee, MD,
Sung-Youl Hyun, MD,
Kook-Yang Park, MD
Department of Thoracic and Cardiovascular Surgery, Gil Hospital, Gachon University of Medicine and Science, Incheon, Republic of Korea
Accepted for publication September 10, 2009.
* Address correspondence to Dr Park, Department of Thoracic and Cardiovascular Surgery, Gil Hospital, Gachon University of Medicine and Science, 1198, Kuwol-Dong, Namdong-Ku, Incheon, 405-760, Republic of Korea (Email: cdgpch{at}gilhospital.com).
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Abstract
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The elephant trunk technique is a novel staged procedure for the treatment of an extensive thoracic aortic aneurysm. Occasionally, entrapment or obstruction in the smaller lumen occurs with the use of the elephant trunk technique in aortic dissection. The general procedure is to excise a generous portion of the dissecting septum distally for a chronic dissecting aneurysm of the descending thoracic aorta. We present the "two elephant trunks" technique. In this procedure, a single side-branched graft is placed in the descending aorta without excising the dissecting septum during a first-stage operation. This modification is simple to perform and has the possibility to prevent interval rupture for a chronic dissecting aneurysm.
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Introduction
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The elephant trunk technique is an innovative staged procedure for the treatment of an extensive thoracic aortic aneurysm. Use of a two-staged elephant trunk technique has resulted in lower mortality with recent surgical advancements. The general procedure is to excise a generous portion of the dissecting septum distally in the chronic dissecting aneurysm of the descending thoracic aorta. Occasionally, entrapment or obstruction in the smaller lumen occurs with the use of the elephant trunk technique for an aortic dissection, and interval rupture would be disastrous after a first-stage operation. It is recommended that a second-staged operation be performed at 4 or 6 weeks after first-stage repair [1, 2]. The dissecting septum should be resected distally to prevent graft complications and both the true and false lumens are perfused with chronic dissection [3].
In this report, we describe the "two elephant trunks technique," in which a single side-branched graft is placed in the descending aorta without excising the dissecting septum.
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Technique
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A 53-year-old man was admitted to our department with a chronic Stanford type A dissecting aneurysm. A chest computed tomographic scan showed an extensive aortic aneurysm where the ascending aorta, descending thoracic aorta, and aortic arch were dilated to 6 cm.
A first-stage operation was performed by the use of a median sternotomy and hypothermic circulatory arrest (to 25 °C). We monitored the perfusion pressure and flow rate with measurement of the right radial arterial pressure by placement of an arterial cannula in a side-grafted right axillary artery.
At first, the proximal dissected aneurysm was excised, and the dilated sinotubular junction was reduced according to the annulus size after cross clamping the proximal aorta. Next, the aortic arch was opened. Selective antegrade cerebral perfusion was delivered through the right axillary artery after clamping the innominate artery and by selectively inserting an auto-inflatable balloon cannula into the left common carotid artery.
The remaining ascending aorta and aortic arch aneurysm were resected. Thereafter, we modified the general elephant trunk technique. At first, we did not resect the dissecting septum at all, even though the original procedure was designed to excise a generous portion of the dissecting septum distally for a chronic dissecting aneurysm of the descending thoracic aorta. Second, we made two elephant trunks by using a side-branched graft instead of a single tube graft. The graft was beveled proximal to the inlet of the side branch, so as to prevent the formation of a small-sized graft kink. The limbs of the two elephant trunks were approximately 10 cm along.
The main graft was inserted into the larger false lumen, and the side-branched graft was inserted into the smaller true lumen (Fig 1A). The proximal part of the trunks was sutured to the remaining descending thoracic aorta. The distal end of a commercial quadrifurcated arch graft was anastomosed to the stump of the descending aorta. Systemic perfusion was started to the distal half of the body after clamping the arch graft proximal to the fourth branch. The proximal portion of the arch graft was anastomosed to the previously repaired ascending aortic stump. Coronary perfusion was started after declamping the aortic arch graft.
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Fig 1. The ascending aorta and aortic arch were replaced with the branched graft by the two elephant trunks technique (A). The chest CT scan showed that the side-branched graft (solid arrow) was inserted in the smaller true lumen and the main graft (dashed arrow) was suspended in the false lumen and the dissecting septum was intact (B, C) before the second stage operation.
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The neck vessels were separately anastomosed to the four branched arch grafts in series for the left subclavian, left common carotid, and innominate arteries during systemic warming. The fourth branch, used for antegrade systemic perfusion, was resected after weaning from cardiopulmonary bypass.
A computed tomographic scan was performed 4 weeks after surgery. The size of the descending aorta was similar to that of the immediately postoperative state. We determined that the two grafts were suspended in both the true and false lumens (Figs 1B and 1C). The second-stage operation was similar to a standard repair for a descending aortic aneurysm. A small graft was removed at the origin site after opening the aorta and the thoracic aortic graft was replaced in a routine manner (Fig 2).
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Fig 2. The descending aortic aneurysm was visible after thoracotomy (A). The side-branched graft (solid arrow) and the main graft (dashed arrow) were clamped separately in both true and false lumens after opening the aorta (B). The chest CT scan showed the thoracic aortic graft and arch graft were replaced totally (C, D).
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Comment
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Staged repair with the elephant trunk technique has become the standard procedure for management of an extensive thoracic aortic aneurysm. However, there is a critical dilemma to select an appropriate interval between staged operations. Estrera and colleagues [1] and Safi and colleagues [4] have reported that the mortality rate during the interval between 31 days and 6 weeks after the proximal operation was 2.9% to 8%, and rupture caused 70% of the deaths that occurred during the short period. These investigators currently recommend performing second-stage repair 4 weeks after the first stage if the condition of the patient permits. LeMaire and colleagues [2] advocated a 6-week recovery period between operations. These investigators reported that 7 patients had distal aortic rupture after first stage repair.
Kouchoukos and colleagues [5] advocated single-stage repairs of extensive thoracic aortic aneurysms, as patients do not have to return for a second-stage repair. Furthermore, aortic rupture is the most common cause of death after a first-stage operation.
For chronic aortic dissection, it has been recommended to excise a generous portion of the dissecting membrane where the length should exceed that of the elephant trunk to ascertain equal perfusion of both distal lumens and to prevent entrapment or obstruction [2, 6]. As long elephant trunks would occlude the intercostal arteries and a spinal cord injury can develop, it has been recommended that a distal elephant trunk graft should be no longer than 10 to 15 cm [3].
The premise for which we based this modification to the standard elephant trunk procedure is that a generous resection of the septum between the true and false lumen predisposes the patient to aneurysmal changes within the chronically dissected portion of the aorta (with the attendant risk of rupture). Although there is no objective evidence of the validity of this assumption, it is supposed that resection of the septum would result in reduced transverse support of the dissected wall. Assuming that it would be better to preserve the septum in the descending thoracic aorta without excising the distal portion, to prevent rupture in the chronic dissecting aneurysm and to maintain forward flow to both lumens, we placed two trunks in the descending aorta instead of one trunk.
The diameter of the proximal descending thoracic aorta was similar as that of the immediately postoperative state 4 weeks after the first-stage operation. At the second stage, there were no difficulties to remove the small side graft in the true lumen.
In conclusion, this modification may be an alternative to prevent interval rupture for a chronic dissecting aneurysm.
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References
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- Estrera AL, Miller III CC, Porat EE, Huynh TTT, Winnerkvist A, Safi HJ. Staged repair of extensive aortic aneurysms Ann Thorac Surg 2002;74:S1803-S1805.[Abstract/Free Full Text]
- LeMaire SA, Carter SA, Coselli JS. The elephant trunk technique for staged repair of complex aneurysms of the entire thoracic aorta Ann Thorac Surg 2006;81:1561-1569.[Abstract/Free Full Text]
- Svensson LG, Kim KH, Blackstone EH, et al. Elephant trunk procedure: newer indications and uses Ann Thorac Surg 2004;78:109-116.[Abstract/Free Full Text]
- Safi HJ, Miller III CC, Estrera AL, et al. Staged repair of extensive aortic aneurysms: long-term experience with the elephant trunk technique Ann Thorac Surg 2007;83:S815-S818.[Abstract/Free Full Text]
- Kouchoukos NT, Mauney MC, Masetti P, Castner CF. Single stage repair of extensive thoracic aortic aneurysms: experience with the arch-first technique and bilateral anterior thoracotomy J Thorac Cardiovasc Surg 2004;128:669-676.[Abstract/Free Full Text]
- Heinemann MK, Buehner B, Jurmann MJ, Borst HG. Use of the "elephant trunk technique" in aortic surgery Ann Thorac Surg 1995;60:2-7.[Abstract/Free Full Text]
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Abstract
Introduction
