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J Thorac Cardiovasc Surg 2003;125:1550-1553
© 2003 The American Association for Thoracic Surgery
Brief Communications |
From the Divisions of Thoracic and Cardiovascular Surgerya and Radiology,b Hannover Medical School, Hannover, Germany.
Received for publication June 26, 2002. Accepted for publication July 7, 2002. Address for reprints: Matthias Karck, MD, Division of Thoracic and Cardiovascular Surgery, Hannover Medical School, Carl-Neuberg-Strasse 1, Hannover 30625, Germany (E-mail: Karck{at}thg.mh-hannover.de).
Combined diseases of the aortic arch and the descending aorta remain among the great challenges facing cardiothoracic surgeons. In 1983, Borst and associates
1 introduced the two-stage elephant trunk principle into cardiovascular surgery, which has greatly facilitated surgical treatment of this special pathologic entity. This approach is based on the prosthetic replacement of the ascending aorta and aortic arch with an elephant trunk extension of the arch graft inserted into the descending aorta during the first-stage operation performed through a median sternotomy. However, the graft segment forming the elephant trunk is floating freely in the descending aortic lumen, thus impeding thrombus formation between the graft and the aneurysmal vessel wall. Because thrombotic occlusion of this space is a prerequisite for reduction of wall stress of the aneurysmal vessel—thereby preventing subsequent growth of the aortic diameter 2—the elephant trunk prosthesis either has to be connected directly to the distal descending portion of the aorta or needs to be extended to the desired level requiring the second-stage operation through a left thoracotomy.
It is evident that comorbidity is a relevant issue in patients with aneurysmal diseases of the aorta, so new therapies to reduce the surgical trauma and risk are desirable. We describe a new approach that allows complete surgical treatment of such combined lesions during a single operation (through a median sternotomy) by using a prototype stent graft that can be placed into the descending aorta in an antegrade fashion through the opened aortic arch.
Methods
Between September and November 2001, a total of 4 patients were operated on after approval was obtained from the institutional review board of Hannover Medical School. Informed consent was obtained in each case.
In each case spiral computed tomographic angiography of the thoracic aorta was performed before the operation to demonstrate the extent of aortic pathologic process and to determine the correct stent graft size. A custom-made, prototype Chavan-Haverich (CH) stent graft was used for the procedure. The CH stent graft (Curative Medical Devices Gmbh, Dresden, Germany) consisted of a Dacron polyester fabric vascular prosthesis with stainless steel stents affixed on the inner aspect at its distal end with the help of polypropylene sutures. All stents were fully covered with the Dacron prosthesis. The proximal portion of the CH stent graft was composed merely of a Dacron tube. The length of the stent graft was at least 5 cm greater than the estimated length of the aortic segment to be bridged. The redundant proximal portion of the Dacron tube was trimmed to an appropriate length and surgically sutured to the aortic wall or to a proximal aortic vascular prosthesis. The total lengths of the stent grafts varied between 200 and 286 mm. The diameter of the proximal end of the CH stent graft was chosen to match the diameter of the proximal aorta or of the proximal surgical graft in the aortic arch to which the CH stent graft had to be sutured. These diameters were 36 mm in 3 cases and 30 mm in 1 case.
The distal stents had a length of 22 mm each; a gap of 5 mm between adjacent stents provided flexibility of the system. The distance between the stents was maintained with the help of two longitudinally oriented stainless steel wires. Depending on individual patient anatomy, the number of stents varied between three and four. To determine the diameters of the distal stents, the diameter of the descending aorta at the site of intended distal docking was used. The diameters of the distal stents were 36 mm in 2 cases and 44 and 46 mm in 1 case each.
The delivery system for the CH stent graft was flexible and could be advanced into the descending aorta over a 0.035-inch super-stiff guide wire (Back-up Meier; Boston Scientific Corporation, Boston, Mass), and possessed a "sheath in sheath" design. It consisted of an outer 30F sheath, an inner 25F sheath, and a central pusher. Withdrawal of the 30F sheath while the inner sheath and the pusher were held steady released the stented portion of the CH stent graft. The proximal Dacron tube could then be released by pulling back both the sheaths simultaneously while holding the pusher steady. After deployment, the stented portion of the CH endograft was modulated onto the aortic wall with the help of an appropriately sized balloon catheter (Medtronic, Inc, Minneapolis, Minn). The individual surgical procedures are described in detail in the clinical summaries.
Clinical summaries
PATIENT 1. Patient 1 was a 71-year-old woman with an aneurysm of the descending aorta (maximum diameter 6 cm) starting at the origin of the left subclavian artery, combined with coronary artery disease. She underwent open antegrade stent graft implantation into the descending aorta and double coronary artery bypass grafting. After median sternotomy, extracorporeal circulation (ECC) was established after cannulation of the ascending aorta and the right atrium. During core cooling to 20°C, double coronary artery bypass grafting was performed. After the target core temperature was reached, ECC was discontinued and selective antegrade cold blood brain perfusion was initiated. Then the stent graft was delivered through the opened aortic arch, and its distal end was anchored at the level of the 10th thoracic vertebra under radiographic control. The proximal, nonstented Dacron graft segment was sutured circumferentially directly distal to the origin of the left subclavian artery; the aortotomy was then closed, and the operation was continued in the usual fashion.
PATIENT 2. Patient 2 was a 50-year-old man with chronic type A aortic dissection. He had critical aortic dilatation proximal to a previously implanted ascending aortic prosthesis as well as the aortic arch and the proximal descending aorta. After resternotomy, ECC was established after cannulation of the aortic arch and the right atrium. After the target temperature of 24°C was reached, ECC was discontinued. After administration of cold blood cardioplegia, opening of the aortic arch to the level of the left subclavian artery, and institution of selective antegrade cold blood brain perfusion, the stent graft was delivered into the true lumen to the level of the 9th vertebra under radiographic control. The proximal nonstented part of the prosthesis was sutured directly into the aortic orifice distal to the left subclavian artery. Then a second precoated graft was implanted to replace the aortic arch and the previously implanted ascending aortic prosthesis.
PATIENTS 3 AND 4. Patients 3 (Figure 1) and 4 were 63- and 65-year-old women with aneurysms of the ascending aorta, the aortic arch, and the proximal descending aorta. In addition, patient 3 had single-vessel coronary artery disease. ECC was established by cannulation of the aortic arch and the right atrium. After core cooling to 26°C, ECC was discontinued. After administration of blood cardioplegia, opening of the arch to the level of the left subclavian artery, and institution of selective antegrade cold blood brain perfusion, the stent graft was delivered into the descending aorta down to level of the 8th thoracic vertebra under radiographic control, with the proximal, nonstented part of the prosthesis subsequently sutured inside the aorta directly distal to the left subclavian artery. Then a second precoated nonstented vascular graft was implanted to replace both the aortic arch and ascending aorta. After cannulation of the prosthesis and reconstitution of ECC, a single venous graft to the left anterior descending coronary artery was implanted in patient 3.
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There were no intraoperative or postoperative deaths. Mean cardiopulmonary bypass time was 234 ± 58 minutes, aortic crossclamp time was 130 ± 41 minutes, circulatory arrest time was 87 ± 39 minutes, and time of selective antegrade brain perfusion during circulatory arrest was 69 ± 43 minutes. Patients 1, 2, and 4 were weaned from the respirator within 48 hours after the operation. Their further courses were uneventful, with no neurologic complications. Patient 3 had a temporary postoperative neurologic dysfunction, as indicated by prolonged intubation followed by moderate confusion and agitation. Two postoperative cerebral computed tomographic scans yielded negative results, and clinical symptoms had resolved completely by discharge on postoperative day 29.
In the 3 patients with aneurysms of the descending aorta, the follow-up computed tomographic scans revealed complete exclusion of the aneurysms. In the patient with the aortic dissection, initiation of thrombus formation in the false lumen in the cranial sections of the descending aorta was noted at 3 months of follow-up. Below the level of the stents, however, persistent perfusion of the false lumen was noted. The diameter of the descending aorta did not increase at the end of follow-up (2-5 months).
Discussion
Thoracic aortic aneurysms are still a challenge for the surgeon, particularly when critical dilatation of the ascending aorta and arch extends beyond the level of the left subclavian artery. Treatment either requires a two-stage approach with the elephant trunk principle or an extensive and traumatic single-stage procedure, generally performed through a clamshell incision. 3-5
Here we have described our early experience with a new approach that allows definitive treatment of such combined lesions during a single-stage procedure that includes antegrade placement of a stented graft into the descending aorta through the opened aortic arch during hypothermic circulatory arrest. This procedure can be performed through a conventional median sternotomy and combines the concepts of the elephant trunk principle and endovascular stenting of descending aortic aneurysms. 1,6 Its advantage lies in the fact that the stented graft, unlike a conventional elephant trunk prosthesis, can be securely anchored at the desired level distal to the descending aortic aneurysm, thereby allowing thrombus formation within the space between the graft and the wall of the aneurysm. The inventor of the elephant trunk technique, Hans G. Borst, has named this approach the "frozen elephant trunk" (unpublished data). The proximal, nonstented portion of the graft is sutured circumferentially into the aorta directly distal to the left subclavian artery with a similar technique to that suggested by Palma for treatment of acute type B aortic dissection. 7 Orihashi and colleagues 8 have also used this approach, under debatable circumstances, however, considering the relatively small and circumscribed aneurysms being excluded. Unlike in their study, most of our patients had to undergo simultaneous replacement of the aneurysmal upstream aorta by implantation of a second vascular prosthesis. This procedure allows single-stage treatment of extensive thoracic aneurysms that otherwise would require either a two-stage procedure or a much more complex single-stage operation.
Except for a fully reversible temporary neurologic dysfunction in patient 3, there was no postoperative morbidity that could be attributed to the fact that stent graft placement currently requires an additional 20 minutes of circulatory arrest. However, we believe that antegrade selective cold blood brain perfusion 9 is an essential tool to protect the brain from ischemic neuronal cell damage. 10,11
Encouraged by the favorable results of this limited series, we evaluate all patients with thoracic aortic aneurysms extending proximal and distal of the left subclavian artery for this new treatment modality, the frozen elephant trunk technique.
References
This article has been cited by other articles:
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  K. Tsagakis, M. Kamler, H. Kuehl, W. Kowalczyk, P. Tossios, M. Thielmann, B. Osswald, R. Erbel, H. Eggebrecht, and H. Jakob Avoidance of proximal endoleak using a hybrid stent graft in arch replacement and descending aorta stenting. Ann. Thorac. Surg., September 1, 2009; 88(3): 773 - 779. [Abstract] [Full Text] [PDF]
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 P. Akhyari, H. Kamiya, T. Heye, A. Lichtenberg, and M. Karck Aortic dissection type A after supra-aortic debranching and implantation of an endovascular stent-graft for type B dissection: A word of caution. J. Thorac. Cardiovasc. Surg., May 1, 2009; 137(5): 1290 - 1292. [Full Text] [PDF]
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 R. Di Bartolomeo, L. Di Marco, A. Armaro, D. Marsilli, A. Leone, E. Pilato, and D. Pacini Treatment of complex disease of the thoracic aorta: the frozen elephant trunk technique with the E-vita open prosthesis Eur. J. Cardiothorac. Surg., April 1, 2009; 35(4): 671 - 676. [Abstract] [Full Text] [PDF]
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M. Karck and H. Kamiya Progress of the treatment for extended aortic aneurysms; is the frozen elephant trunk technique the next standard in the treatment of complex aortic disease including the arch? Eur. J. Cardiothorac. Surg., June 1, 2008; 33(6): 1007 - 1013. [Abstract] [Full Text] [PDF]
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 W. K. Baek, Y. Han Yoon, J. Taek Kim, and K. Ho Kim Recurrent type B intramural hematoma progressed into type A acute aortic dissection in a young otherwise healthy woman: are there unknown background factors? Interactive CardioVascular and Thoracic Surgery, April 1, 2007; 6(2): 255 - 256. [Abstract] [Full Text] [PDF]
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 M. A. Pichlmaier, O. E. Teebken, H. Baraki, and A. Haverich The frozen elephant trunk technique MMCTS, March 29, 2007; 2007(0329): 1990. [Abstract] [Full Text] [PDF]
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H. Baraki, C. Hagl, N. Khaladj, K. Kallenbach, J. Weidemann, A. Haverich, and M. Karck The Frozen Elephant Trunk Technique for Treatment of Thoracic Aortic Aneurysms Ann. Thorac. Surg., February 1, 2007; 83(2): S819 - S823. [Abstract] [Full Text] [PDF]
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 R. K. Greenberg, F. Haddad, L. Svensson, S. O'Neill, E. Walker, S. P. Lyden, D. Clair, and B. Lytle Hybrid Approaches to Thoracic Aortic Aneurysms: The Role of Endovascular Elephant Trunk Completion Circulation, October 25, 2005; 112(17): 2619 - 2626. [Abstract] [Full Text] [PDF]
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M. Karck, A. Chavan, N. Khaladj, H. Friedrich, C. Hagl, and A. Haverich The frozen elephant trunk technique for the treatment of extensive thoracic aortic aneurysms: operative results and follow-up Eur. J. Cardiothorac. Surg., August 1, 2005; 28(2): 286 - 290. [Abstract] [Full Text] [PDF]
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H. Matsuda, Y. Tsuji, K. Sugimoto, and Y. Okita Secondary elephant trunk fixation with endovascular stent grafting for extensive/multiple thoracic aortic aneurysm Eur. J. Cardiothorac. Surg., August 1, 2005; 28(2): 335 - 336. [Abstract] [Full Text] [PDF]
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M. Grabenwoger, T. Fleck, M. Ehrlich, M. Czerny, D. Hutschala, M. Schoder, J. Lammer, and E. Wolner Secondary surgical interventions after endovascular stent-grafting of the thoracic aorta Eur. J. Cardiothorac. Surg., September 1, 2004; 26(3): 608 - 613. [Abstract] [Full Text] [PDF]
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