Ann Thorac Surg 2009;88:779-780. doi:10.1016/j.athoracsur.2009.07.011
© 2009 The Society of Thoracic Surgeons
Original Articles: Adult Cardiac
Invited Commentary
John A. Elefteriades, MD
Section of Cardiac Surgery, Yale University School of Medicine, Boardman 2, 333 Cedar St, New Haven, CT 06510
(Email: john.elefteriades{at}yale.edu).
This article presents further experience with the "frozen elephant trunk" technique for ascending aortic dissection [1]. The authors are to be commended for their development of this technique and the pertinent specialized hybrid endograft–conventional graft. (We should note that one of the authors has disclosed a financial interest regarding the manufacturer of this device.) The authors are to be congratulated for their excellent clinical results.
There are several weaknesses of this study. The analyses of these patients really should have been confined only to those with acute type A aortic dissection. The contamination with chronic cases, degenerative aneurysms, descending pathology, and penetrating ulcers makes interpretation difficult. The follow-up is short, as is obligatory with the new technology. Also, it is unclear how this technology can be applied without a total arch replacement, which the authors indicated was the case in nearly half their patients.
We must also keep in mind several other important points as follows:
- 1 Is there truly a need for adjunctive descending stenting? The incidence of significant dilatation of the descending aorta in the long term after conventional ascending aortic replacement for type A dissection appears to be relatively low. At our institution, we have needed to reoperate late for descending aortic enlargement in only a very small proportion of our patients [2]. In another recent report, only 12 of 221 patients required late reoperation for thoracoabdominal aneurysm [3]. Thus, it is unclear that any additional measures need to be taken at the time of initial repair.
- 2 Does adjunctive descending aortic stenting really improve long-term survival after type A repair? Follow-up, understandably, is short at this stage in the technologic development. Surgeons experienced in aortic repair will recognize that the intimal flap has no strength. It can not hold sutures. So, it is difficult to envision how applying an endograft against this layer can produce any substantive, durable anatomical impact.
- 3 There is a good surgical alternative: extended resection at the time of original type A repair. If it is believed that there is a need to do more at the time of initial repair of type A dissection, then a resection and conventional elephant trunk placement should be considered. We put the elephant trunk between the left carotid and the left subclavian arteries. The elephant trunk, invaginated into the descending aorta during the distal anastomosis, confers inner strength in a manner similar to an inner strip of cloth felt. The distal anastomosis is easily and quickly performed at this level, where the aorta is smaller in circumference and quite accessible. A single patch of innominate and left carotid arteries is then applied to the main graft after the graft is evaginated. This procedure extirpates not only the ascending aorta, but also most of the aortic arch. This procedure leaves an elephant trunk for future use, in case this patient turns out to be one of the few who later needs descending surgery. This is becoming a preferred technique at our institution (Fig 1).
- 4 General concerns about endografts in the medium term. The recent International Aortic Symposium in Liege, Belgium, after thorough presentation of all available major mid-term studies of stent therapy in the abdomen or chest, concluded that stent therapy was essentially a "sham" intervention with little up-front morbidity but no long-term benefit. By the 2-year point, patients did better, by DREAM and EVAR-2 results, with conventional surgical therapy or with sole medical therapy, than they did with stent grafting. Also, the results of the INSTEAD trial of stent therapy for uncomplicated type B aortic dissection were very discouraging; these were never published, but were presented at multiple forums. If a stent in a dissected descending aorta is a good thing, it would have been expected to have improved outcomes in the INSTEAD trial [4, 5].
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Fig 1. Technique of arch replacement with anastomosis between left carotid and left subclarian arteries.
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Therefore, the authors are to be congratulated for developing new endovascular technology appropriate for aortic dissection application and for demonstrating its safety in the short term. It is unclear whether this therapy will indeed improve long-term prognosis or lead to lower rates of late surgical reintervention. This therapy can not be recommended at this time, except on an investigational basis.
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References
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- Tsagakis K, Kamler M, Kuehl H, et al. Avoidance of proximal endoleak using a hybrid stent graft in arch replacement and descending aorta stenting Ann Thorac Surg 2009;88:773-780.[Abstract/Free Full Text]
- Dobrilovic N, Elefteriades JA. Stenting the descending aorta during repair of type A dissection: technology looking for an application? J Thorac Cardiovasc Surg 2006;131:777-778.[Free Full Text]
- Geirsson A, Bavaria JE, Swarr D, et al. Fate of the residual distal and proximal aorta after acute type A dissection repair using a contemporary surgical reconstruction algorithm Ann Thorac Surg 2007;84:1955-1964.[Abstract/Free Full Text]
- EVAR trial participants Endovascular aneurysm repair and outcome in patients unfit for open repair of abdominal aortic aneurysm (EVAR trial 2): randomized controlled trial Lancet 2005;365:2187-2192.[Medline]
- Blankensteijn J. Late results of endovascular aneurysm repair versus open aneurysm repair. International Meeting on Aortic Aneurysms: New insights into an old problem. Palais des Congres, September 19–20, 2008; Liege, Belgium.
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