Frozen Elephant Trunk Technique for Extensive Chronic Thoracic Aortic Dissection: Is it the Final Answer?

Abstract

The optimal method of management of extensive chronic aortic dissection involving most, or all, of the thoracic aorta has not been determined. Most patients who present with this condition have had previous graft replacement of the ascending aorta for acute type A dissection and present with enlargement of the dissected aortic arch and descending thoracic aorta. A commonly used approach has been a staged one, replacing the aortic arch at the first stage, and the descending thoracic or thoracoabdominal aorta at the second stage. In 1983, Borst and colleagues [1Borst H.G. Walterbusch G. Schaps D. Extensive aortic replacement using “elephant trunk” prosthesis.Thorac Cardiovasc Surg. 1983; 31: 37-40Crossref PubMed Scopus (540) Google Scholar] introduced the elephant trunk technique as a method to facilitate the second stage, and it has been applied to patients with extensive chronic dissection and degenerative disease [2Crawford E.S. Coselli J.S. Svensson L.G. Safi H.J. Hess K.R. Diffuse aneurysmal disease (chronic aortic dissection, marfan, and mega aorta syndromes) and multiple aneurysm Treatment by subtotal and total aortic replacement emphasizing the elephant trunk operation.Ann Surg. 1990; 211: 521-537Crossref PubMed Scopus (193) Google Scholar]. Subsequent studies that have included patients with chronic aortic dissection have documented that the cumulative mortality and major morbidity associated with the staged procedures is not insignificant, and that a substantial number of patients either died in the interval between the 2 procedures, or did not undergo the second procedure [3Schepens M.A. Dossche K.M. Morshuis W.J. van den Barselaar P.J. Heijmen R.H. Vermeulen F.E. The elephant trunk technique: operative results in 100 consecutive patients.Eur J Cardiothorac Surg. 2002; 21: 276-281Crossref PubMed Scopus (117) Google Scholar, 4Safi H.J. Miller III, C.C. Estrera A.L. et al.Staged repair of extensive aortic aneurysms: long-term experience with elephant trunk technique.Ann Surg. 2004; 240: 677-685PubMed Google Scholar, 5Svensson L.G. Kim K.H. Blackstone E.H. et al.Elephant trunk procedure: newer indications and uses.Ann Thorac Surg. 2004; 78: 109-116Abstract Full Text Full Text PDF PubMed Scopus (186) Google Scholar, 6LeMairé S.A. Carter S.A. Coselli J.S. The elephant trunk technique for staged repair of complex aneurysms of the entire thoracic aorta.Ann Thorac Surg. 2006; 81: 1561-1569Abstract Full Text Full Text PDF PubMed Scopus (146) Google Scholar]. As a consequence, alternative surgical techniques have been explored. One of the methods proposed is the stented or “frozen” elephant trunk procedure, which involves placement of a stented endovascular graft into the descending thoracic aorta through the opened aorticFor related article, see page 1663 arch, and replacement of the ascending aorta and arch with a conventional polyester tube or branched graft [7Kato M. Ohnishi K. Kaneko M. et al.New graft-implanting method for thoracic aortic aneurysm or dissection with a stented graft.Circulation. 1996; 94: II188-II193PubMed Google Scholar]. A rationale for this approach is to promote thrombosis of the false lumen and eliminate or substantially reduce the need for a second-stage procedure.In this issue of The Annals, Pacini and colleagues [8Pacini D. Tsagakis K. Jakob H. The frozen elephant trunk for the treatment of chronic dissection of the thoracic aorta: a multicenter experience.Ann Thorac Surg. 2011; 92: 1663-1670Abstract Full Text Full Text PDF PubMed Scopus (98) Google Scholar] report a multicenter experience with a commercially prepared graft (E-vita; Jotec, Hechingen, Germany), composed of a 15-cm self-expandable, nitinol-covered stent graft with an integrated proximal nonstented vascular prosthesis for the treatment of chronic aortic dissection in 90 patients. The majority of patients had type A dissection (77%) and the remainder had type B dissection. No standard protocol for insertion of the device was utilized. Hospital mortality was 12.2%, major spinal cord ischemic injury occurred in 8 patients (8.9%), and stroke in 1 patient. Acute renal failure requiring dialysis occurred in 18 patients (20%) and 28 patients (31%) required ventilator support for more than 72 hours. Follow-up imaging, obtained at a mean of 20 ± 16 months in approximately 80% of the hospital survivors, demonstrated complete thrombosis of the false lumen surrounding the stent graft in 92% of patients. Complete thrombosis of the false lumen at the distal thoracic aortic level was noted in 48% of the patients, and at the abdominal aortic level in 19%. The overall dimension of the descending thoracic aorta did not decrease significantly. Secondary aortic repair was required in 20 (22.5%) of the operative survivors (18 endovascular and 2 open).The role of endovascular stent grafting for patients with chronic aortic dissection involving the descending thoracic aorta remains unsettled [9Swee W. Dake M.D. Endovascular management of thoracic dissections.Circulation. 2008; 117: 1460-1473Crossref PubMed Scopus (71) Google Scholar, 10Svensson L.G. Kouchoukos N.T. Miller D.C. et al.Expert consensus document on the treatment of descending thoracic aortic disease using endovascular stent-grafts.Ann Thorac Surg. 2008; 85: S1-S41Abstract Full Text Full Text PDF PubMed Scopus (708) Google Scholar]. Previous studies of stent grafting, including those employing a stented elephant trunk, have consistently shown that partial or complete patency of the false lumen beyond the stent graft persists in over 50% to 60% of patients [11Shimono T. Kato N. Yasuda F. et al.Transluminal stent-graft placements for the treatments of acute onset and chronic aortic dissections.Circulation. 2002; 106: I241-I247PubMed Google Scholar, 12Kusagawa H. Shimono T. Ishida M. et al.Changes in false lumen after transluminal stent-graft placement in aortic dissections: six years' experience.Circulation. 2005; 111: 2951-2957Crossref PubMed Scopus (131) Google Scholar, 13Pichlmaier M. Teebken O.E. Khaladj N. Weidemann J. Galanski M. Haverich A. Distal aortic surgery following arch replacement with a frozen elephant trunk.Eur J Cardiothorac Surg. 2008; 34: 600-604Crossref PubMed Scopus (35) Google Scholar, 14Di Bartolomeo R. Di Marco L. Armaro A. et al.Treatment of complex disease of the thoracic aorta: the frozen elephant trunk technique with the E-vita prosthesis.Eur J Cardiothorac Surg. 2009; 35: 671-675Crossref PubMed Scopus (74) Google Scholar, 15Li B. Sun L. Chang Q. et al.Total arch replacement with stented elephant trunk technique: a proposed treatment for complicated Stanford type B aortic dissection.J Card Surg. 2009; 24: 704-709Crossref PubMed Scopus (11) Google Scholar, 16Kouchoukos N.T. The stented elephant trunk: is it an optimal strategy?.J Card Surg. 2009; 24: 702-703Crossref PubMed Scopus (3) Google Scholar, 17Ius F. Hagl C. Haverich A. Pichlmaier M. Elephant trunk procedure 27 years after Borst: what remains and what is new?.Eur J Cardio Thorac Surg. 2011; 40: 1-11Crossref PubMed Scopus (65) Google Scholar] and this was confirmed in the study by Pacini and colleagues [8Pacini D. Tsagakis K. Jakob H. The frozen elephant trunk for the treatment of chronic dissection of the thoracic aorta: a multicenter experience.Ann Thorac Surg. 2011; 92: 1663-1670Abstract Full Text Full Text PDF PubMed Scopus (98) Google Scholar]. A number of these patients have undergone subsequent open or interventional procedures on the remaining aorta [11Shimono T. Kato N. Yasuda F. et al.Transluminal stent-graft placements for the treatments of acute onset and chronic aortic dissections.Circulation. 2002; 106: I241-I247PubMed Google Scholar, 12Kusagawa H. Shimono T. Ishida M. et al.Changes in false lumen after transluminal stent-graft placement in aortic dissections: six years' experience.Circulation. 2005; 111: 2951-2957Crossref PubMed Scopus (131) Google Scholar, 13Pichlmaier M. Teebken O.E. Khaladj N. Weidemann J. Galanski M. Haverich A. Distal aortic surgery following arch replacement with a frozen elephant trunk.Eur J Cardiothorac Surg. 2008; 34: 600-604Crossref PubMed Scopus (35) Google Scholar, 14Di Bartolomeo R. Di Marco L. Armaro A. et al.Treatment of complex disease of the thoracic aorta: the frozen elephant trunk technique with the E-vita prosthesis.Eur J Cardiothorac Surg. 2009; 35: 671-675Crossref PubMed Scopus (74) Google Scholar, 15Li B. Sun L. Chang Q. et al.Total arch replacement with stented elephant trunk technique: a proposed treatment for complicated Stanford type B aortic dissection.J Card Surg. 2009; 24: 704-709Crossref PubMed Scopus (11) Google Scholar, 16Kouchoukos N.T. The stented elephant trunk: is it an optimal strategy?.J Card Surg. 2009; 24: 702-703Crossref PubMed Scopus (3) Google Scholar, 17Ius F. Hagl C. Haverich A. Pichlmaier M. Elephant trunk procedure 27 years after Borst: what remains and what is new?.Eur J Cardio Thorac Surg. 2011; 40: 1-11Crossref PubMed Scopus (65) Google Scholar].Are the results with the stented elephant trunk reported in this multiinstitutional study, as well as reports from single institutions, sufficiently favorable, when compared with other techniques, to consider it the method of choice [18Karck M. Kamiya H. 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. 2008; 33: 1007-1013Crossref PubMed Scopus (72) Google Scholar]? The available data would suggest otherwise. Hospital mortality and major morbidity with this procedure have not been insignificant. In the report of Pacini and colleagues [8Pacini D. Tsagakis K. Jakob H. The frozen elephant trunk for the treatment of chronic dissection of the thoracic aorta: a multicenter experience.Ann Thorac Surg. 2011; 92: 1663-1670Abstract Full Text Full Text PDF PubMed Scopus (98) Google Scholar] the duration of cardiopulmonary bypass exceeded 4 hours and was associated with lengthy intervals of myocardial ischemia (145 minutes) and cerebral perfusion (84 minutes). This has been noted in other series [13Pichlmaier M. Teebken O.E. Khaladj N. Weidemann J. Galanski M. Haverich A. Distal aortic surgery following arch replacement with a frozen elephant trunk.Eur J Cardiothorac Surg. 2008; 34: 600-604Crossref PubMed Scopus (35) Google Scholar, 14Di Bartolomeo R. Di Marco L. Armaro A. et al.Treatment of complex disease of the thoracic aorta: the frozen elephant trunk technique with the E-vita prosthesis.Eur J Cardiothorac Surg. 2009; 35: 671-675Crossref PubMed Scopus (74) Google Scholar, 15Li B. Sun L. Chang Q. et al.Total arch replacement with stented elephant trunk technique: a proposed treatment for complicated Stanford type B aortic dissection.J Card Surg. 2009; 24: 704-709Crossref PubMed Scopus (11) Google Scholar, 19Kato M. Kurantani T. Kaneko M. Kyo S. Ohnishi K. The results of total arch graft implantation with open stent-graft placement for type A aortic dissection.J Thorac Cardiovasc Surg. 2002; 124: 531-540Abstract Full Text Full Text PDF PubMed Scopus (104) Google Scholar, 20Baraki H. Hagl C. Khaladj N. et al.The frozen elephant trunk technique for treatment of thoracic aortic aneurysms.Ann Thorac Surg. 2007; 83: S819-S823Abstract Full Text Full Text PDF PubMed Scopus (88) Google Scholar]. The prevalence of major spinal cord ischemic injury is also of concern. The length of the elephant trunk has been shown in several series to be correlated with the development of spinal cord ischemic injury [2Crawford E.S. Coselli J.S. Svensson L.G. Safi H.J. Hess K.R. Diffuse aneurysmal disease (chronic aortic dissection, marfan, and mega aorta syndromes) and multiple aneurysm Treatment by subtotal and total aortic replacement emphasizing the elephant trunk operation.Ann Surg. 1990; 211: 521-537Crossref PubMed Scopus (193) Google Scholar, 17Ius F. Hagl C. Haverich A. Pichlmaier M. Elephant trunk procedure 27 years after Borst: what remains and what is new?.Eur J Cardio Thorac Surg. 2011; 40: 1-11Crossref PubMed Scopus (65) Google Scholar]. Although a similar correlation was not observed in their study, Pacini and colleagues recommend shortening of the elephant trunk from 15 cm to 12 cm. This will reduce the extent of thrombosis of the false lumen and may thus further limit the effectiveness of the stent graft. The prolonged duration of distal aortic ischemia (75 ± 22 minutes) may be another factor that contributed to the development of spinal cord ischemic injury.Interruption of communications between fenestrations proximal and distal to the stent graft that occurs from fixation of the graft to the aortic wall increases the probability of thrombosis in the false lumen distal to the stent graft, and the risk of impaired perfusion of intercostal, renal, and visceral arteries that originate from the false lumen. The occurrence of paralysis, cholecystitis, pancreatitis, and renal and multiple organ failure noted by Pacini and colleagues [8Pacini D. Tsagakis K. Jakob H. The frozen elephant trunk for the treatment of chronic dissection of the thoracic aorta: a multicenter experience.Ann Thorac Surg. 2011; 92: 1663-1670Abstract Full Text Full Text PDF PubMed Scopus (98) Google Scholar] could be explained by this phenomenon. Thus, obliteration of the false lumen distal to a stent graft may not be a desirable objective. The authors rightly point out the importance of determining preoperatively the presence of distal reentry sites, and imply that their technique may not be advisable if distal fenestrations are not present or the visceral and renal arteries arise from the false lumen. It is not stated whether routine screening for such fenestrations was carried out in the 90 patients. It is worth noting that open surgical repair with fenestration of the distal aorta assures continued patency of the false lumen and eliminates these risks. When the aneurysmal proximal and mid-descending thoracic aortic segments are treated by graft replacement and distal fenestration, progressive dilatation of the remaining aorta and reoperation have been infrequent [21Kouchoukos N.T. Masetti P. Mauney M.C. Murphy M.C. Castner C.F. One-stage repair of extensive chronic aortic dissection using the arch-first technique and bilateral anterior thoracotomy.Ann Thorac Surg. 2008; 86: 1502-1509Abstract Full Text Full Text PDF PubMed Scopus (54) Google Scholar].Clearly, uncertainties remain regarding the relative effectiveness of the frozen elephant trunk technique when compared with two-stage and one-stage procedures for the management of extensive chronic aortic dissection. Longer follow-up to assess the fate of the patent false lumen and the need for subsequent procedures on the remaining thoracic and abdominal aorta is essential before this procedure is widely applied. The optimal method of management of extensive chronic aortic dissection involving most, or all, of the thoracic aorta has not been determined. Most patients who present with this condition have had previous graft replacement of the ascending aorta for acute type A dissection and present with enlargement of the dissected aortic arch and descending thoracic aorta. A commonly used approach has been a staged one, replacing the aortic arch at the first stage, and the descending thoracic or thoracoabdominal aorta at the second stage. In 1983, Borst and colleagues [1Borst H.G. Walterbusch G. Schaps D. Extensive aortic replacement using “elephant trunk” prosthesis.Thorac Cardiovasc Surg. 1983; 31: 37-40Crossref PubMed Scopus (540) Google Scholar] introduced the elephant trunk technique as a method to facilitate the second stage, and it has been applied to patients with extensive chronic dissection and degenerative disease [2Crawford E.S. Coselli J.S. Svensson L.G. Safi H.J. Hess K.R. Diffuse aneurysmal disease (chronic aortic dissection, marfan, and mega aorta syndromes) and multiple aneurysm Treatment by subtotal and total aortic replacement emphasizing the elephant trunk operation.Ann Surg. 1990; 211: 521-537Crossref PubMed Scopus (193) Google Scholar]. Subsequent studies that have included patients with chronic aortic dissection have documented that the cumulative mortality and major morbidity associated with the staged procedures is not insignificant, and that a substantial number of patients either died in the interval between the 2 procedures, or did not undergo the second procedure [3Schepens M.A. Dossche K.M. Morshuis W.J. van den Barselaar P.J. Heijmen R.H. Vermeulen F.E. The elephant trunk technique: operative results in 100 consecutive patients.Eur J Cardiothorac Surg. 2002; 21: 276-281Crossref PubMed Scopus (117) Google Scholar, 4Safi H.J. Miller III, C.C. Estrera A.L. et al.Staged repair of extensive aortic aneurysms: long-term experience with elephant trunk technique.Ann Surg. 2004; 240: 677-685PubMed Google Scholar, 5Svensson L.G. Kim K.H. Blackstone E.H. et al.Elephant trunk procedure: newer indications and uses.Ann Thorac Surg. 2004; 78: 109-116Abstract Full Text Full Text PDF PubMed Scopus (186) Google Scholar, 6LeMairé S.A. Carter S.A. Coselli J.S. The elephant trunk technique for staged repair of complex aneurysms of the entire thoracic aorta.Ann Thorac Surg. 2006; 81: 1561-1569Abstract Full Text Full Text PDF PubMed Scopus (146) Google Scholar]. As a consequence, alternative surgical techniques have been explored. One of the methods proposed is the stented or “frozen” elephant trunk procedure, which involves placement of a stented endovascular graft into the descending thoracic aorta through the opened aorticFor related article, see page 1663 arch, and replacement of the ascending aorta and arch with a conventional polyester tube or branched graft [7Kato M. Ohnishi K. Kaneko M. et al.New graft-implanting method for thoracic aortic aneurysm or dissection with a stented graft.Circulation. 1996; 94: II188-II193PubMed Google Scholar]. A rationale for this approach is to promote thrombosis of the false lumen and eliminate or substantially reduce the need for a second-stage procedure. For related article, see page 1663 For related article, see page 1663 In this issue of The Annals, Pacini and colleagues [8Pacini D. Tsagakis K. Jakob H. The frozen elephant trunk for the treatment of chronic dissection of the thoracic aorta: a multicenter experience.Ann Thorac Surg. 2011; 92: 1663-1670Abstract Full Text Full Text PDF PubMed Scopus (98) Google Scholar] report a multicenter experience with a commercially prepared graft (E-vita; Jotec, Hechingen, Germany), composed of a 15-cm self-expandable, nitinol-covered stent graft with an integrated proximal nonstented vascular prosthesis for the treatment of chronic aortic dissection in 90 patients. The majority of patients had type A dissection (77%) and the remainder had type B dissection. No standard protocol for insertion of the device was utilized. Hospital mortality was 12.2%, major spinal cord ischemic injury occurred in 8 patients (8.9%), and stroke in 1 patient. Acute renal failure requiring dialysis occurred in 18 patients (20%) and 28 patients (31%) required ventilator support for more than 72 hours. Follow-up imaging, obtained at a mean of 20 ± 16 months in approximately 80% of the hospital survivors, demonstrated complete thrombosis of the false lumen surrounding the stent graft in 92% of patients. Complete thrombosis of the false lumen at the distal thoracic aortic level was noted in 48% of the patients, and at the abdominal aortic level in 19%. The overall dimension of the descending thoracic aorta did not decrease significantly. Secondary aortic repair was required in 20 (22.5%) of the operative survivors (18 endovascular and 2 open). The role of endovascular stent grafting for patients with chronic aortic dissection involving the descending thoracic aorta remains unsettled [9Swee W. Dake M.D. Endovascular management of thoracic dissections.Circulation. 2008; 117: 1460-1473Crossref PubMed Scopus (71) Google Scholar, 10Svensson L.G. Kouchoukos N.T. Miller D.C. et al.Expert consensus document on the treatment of descending thoracic aortic disease using endovascular stent-grafts.Ann Thorac Surg. 2008; 85: S1-S41Abstract Full Text Full Text PDF PubMed Scopus (708) Google Scholar]. Previous studies of stent grafting, including those employing a stented elephant trunk, have consistently shown that partial or complete patency of the false lumen beyond the stent graft persists in over 50% to 60% of patients [11Shimono T. Kato N. Yasuda F. et al.Transluminal stent-graft placements for the treatments of acute onset and chronic aortic dissections.Circulation. 2002; 106: I241-I247PubMed Google Scholar, 12Kusagawa H. Shimono T. Ishida M. et al.Changes in false lumen after transluminal stent-graft placement in aortic dissections: six years' experience.Circulation. 2005; 111: 2951-2957Crossref PubMed Scopus (131) Google Scholar, 13Pichlmaier M. Teebken O.E. Khaladj N. Weidemann J. Galanski M. Haverich A. Distal aortic surgery following arch replacement with a frozen elephant trunk.Eur J Cardiothorac Surg. 2008; 34: 600-604Crossref PubMed Scopus (35) Google Scholar, 14Di Bartolomeo R. Di Marco L. Armaro A. et al.Treatment of complex disease of the thoracic aorta: the frozen elephant trunk technique with the E-vita prosthesis.Eur J Cardiothorac Surg. 2009; 35: 671-675Crossref PubMed Scopus (74) Google Scholar, 15Li B. Sun L. Chang Q. et al.Total arch replacement with stented elephant trunk technique: a proposed treatment for complicated Stanford type B aortic dissection.J Card Surg. 2009; 24: 704-709Crossref PubMed Scopus (11) Google Scholar, 16Kouchoukos N.T. The stented elephant trunk: is it an optimal strategy?.J Card Surg. 2009; 24: 702-703Crossref PubMed Scopus (3) Google Scholar, 17Ius F. Hagl C. Haverich A. Pichlmaier M. Elephant trunk procedure 27 years after Borst: what remains and what is new?.Eur J Cardio Thorac Surg. 2011; 40: 1-11Crossref PubMed Scopus (65) Google Scholar] and this was confirmed in the study by Pacini and colleagues [8Pacini D. Tsagakis K. Jakob H. The frozen elephant trunk for the treatment of chronic dissection of the thoracic aorta: a multicenter experience.Ann Thorac Surg. 2011; 92: 1663-1670Abstract Full Text Full Text PDF PubMed Scopus (98) Google Scholar]. A number of these patients have undergone subsequent open or interventional procedures on the remaining aorta [11Shimono T. Kato N. Yasuda F. et al.Transluminal stent-graft placements for the treatments of acute onset and chronic aortic dissections.Circulation. 2002; 106: I241-I247PubMed Google Scholar, 12Kusagawa H. Shimono T. Ishida M. et al.Changes in false lumen after transluminal stent-graft placement in aortic dissections: six years' experience.Circulation. 2005; 111: 2951-2957Crossref PubMed Scopus (131) Google Scholar, 13Pichlmaier M. Teebken O.E. Khaladj N. Weidemann J. Galanski M. Haverich A. Distal aortic surgery following arch replacement with a frozen elephant trunk.Eur J Cardiothorac Surg. 2008; 34: 600-604Crossref PubMed Scopus (35) Google Scholar, 14Di Bartolomeo R. Di Marco L. Armaro A. et al.Treatment of complex disease of the thoracic aorta: the frozen elephant trunk technique with the E-vita prosthesis.Eur J Cardiothorac Surg. 2009; 35: 671-675Crossref PubMed Scopus (74) Google Scholar, 15Li B. Sun L. Chang Q. et al.Total arch replacement with stented elephant trunk technique: a proposed treatment for complicated Stanford type B aortic dissection.J Card Surg. 2009; 24: 704-709Crossref PubMed Scopus (11) Google Scholar, 16Kouchoukos N.T. The stented elephant trunk: is it an optimal strategy?.J Card Surg. 2009; 24: 702-703Crossref PubMed Scopus (3) Google Scholar, 17Ius F. Hagl C. Haverich A. Pichlmaier M. Elephant trunk procedure 27 years after Borst: what remains and what is new?.Eur J Cardio Thorac Surg. 2011; 40: 1-11Crossref PubMed Scopus (65) Google Scholar]. Are the results with the stented elephant trunk reported in this multiinstitutional study, as well as reports from single institutions, sufficiently favorable, when compared with other techniques, to consider it the method of choice [18Karck M. Kamiya H. 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. 2008; 33: 1007-1013Crossref PubMed Scopus (72) Google Scholar]? The available data would suggest otherwise. Hospital mortality and major morbidity with this procedure have not been insignificant. In the report of Pacini and colleagues [8Pacini D. Tsagakis K. Jakob H. The frozen elephant trunk for the treatment of chronic dissection of the thoracic aorta: a multicenter experience.Ann Thorac Surg. 2011; 92: 1663-1670Abstract Full Text Full Text PDF PubMed Scopus (98) Google Scholar] the duration of cardiopulmonary bypass exceeded 4 hours and was associated with lengthy intervals of myocardial ischemia (145 minutes) and cerebral perfusion (84 minutes). This has been noted in other series [13Pichlmaier M. Teebken O.E. Khaladj N. Weidemann J. Galanski M. Haverich A. Distal aortic surgery following arch replacement with a frozen elephant trunk.Eur J Cardiothorac Surg. 2008; 34: 600-604Crossref PubMed Scopus (35) Google Scholar, 14Di Bartolomeo R. Di Marco L. Armaro A. et al.Treatment of complex disease of the thoracic aorta: the frozen elephant trunk technique with the E-vita prosthesis.Eur J Cardiothorac Surg. 2009; 35: 671-675Crossref PubMed Scopus (74) Google Scholar, 15Li B. Sun L. Chang Q. et al.Total arch replacement with stented elephant trunk technique: a proposed treatment for complicated Stanford type B aortic dissection.J Card Surg. 2009; 24: 704-709Crossref PubMed Scopus (11) Google Scholar, 19Kato M. Kurantani T. Kaneko M. Kyo S. Ohnishi K. The results of total arch graft implantation with open stent-graft placement for type A aortic dissection.J Thorac Cardiovasc Surg. 2002; 124: 531-540Abstract Full Text Full Text PDF PubMed Scopus (104) Google Scholar, 20Baraki H. Hagl C. Khaladj N. et al.The frozen elephant trunk technique for treatment of thoracic aortic aneurysms.Ann Thorac Surg. 2007; 83: S819-S823Abstract Full Text Full Text PDF PubMed Scopus (88) Google Scholar]. The prevalence of major spinal cord ischemic injury is also of concern. The length of the elephant trunk has been shown in several series to be correlated with the development of spinal cord ischemic injury [2Crawford E.S. Coselli J.S. Svensson L.G. Safi H.J. Hess K.R. Diffuse aneurysmal disease (chronic aortic dissection, marfan, and mega aorta syndromes) and multiple aneurysm Treatment by subtotal and total aortic replacement emphasizing the elephant trunk operation.Ann Surg. 1990; 211: 521-537Crossref PubMed Scopus (193) Google Scholar, 17Ius F. Hagl C. Haverich A. Pichlmaier M. Elephant trunk procedure 27 years after Borst: what remains and what is new?.Eur J Cardio Thorac Surg. 2011; 40: 1-11Crossref PubMed Scopus (65) Google Scholar]. Although a similar correlation was not observed in their study, Pacini and colleagues recommend shortening of the elephant trunk from 15 cm to 12 cm. This will reduce the extent of thrombosis of the false lumen and may thus further limit the effectiveness of the stent graft. The prolonged duration of distal aortic ischemia (75 ± 22 minutes) may be another factor that contributed to the development of spinal cord ischemic injury. Interruption of communications between fenestrations proximal and distal to the stent graft that occurs from fixation of the graft to the aortic wall increases the probability of thrombosis in the false lumen distal to the stent graft, and the risk of impaired perfusion of intercostal, renal, and visceral arteries that originate from the false lumen. The occurrence of paralysis, cholecystitis, pancreatitis, and renal and multiple organ failure noted by Pacini and colleagues [8Pacini D. Tsagakis K. Jakob H. The frozen elephant trunk for the treatment of chronic dissection of the thoracic aorta: a multicenter experience.Ann Thorac Surg. 2011; 92: 1663-1670Abstract Full Text Full Text PDF PubMed Scopus (98) Google Scholar] could be explained by this phenomenon. Thus, obliteration of the false lumen distal to a stent graft may not be a desirable objective. The authors rightly point out the importance of determining preoperatively the presence of distal reentry sites, and imply that their technique may not be advisable if distal fenestrations are not present or the visceral and renal arteries arise from the false lumen. It is not stated whether routine screening for such fenestrations was carried out in the 90 patients. It is worth noting that open surgical repair with fenestration of the distal aorta assures continued patency of the false lumen and eliminates these risks. When the aneurysmal proximal and mid-descending thoracic aortic segments are treated by graft replacement and distal fenestration, progressive dilatation of the remaining aorta and reoperation have been infrequent [21Kouchoukos N.T. Masetti P. Mauney M.C. Murphy M.C. Castner C.F. One-stage repair of extensive chronic aortic dissection using the arch-first technique and bilateral anterior thoracotomy.Ann Thorac Surg. 2008; 86: 1502-1509Abstract Full Text Full Text PDF PubMed Scopus (54) Google Scholar]. Clearly, uncertainties remain regarding the relative effectiveness of the frozen elephant trunk technique when compared with two-stage and one-stage procedures for the management of extensive chronic aortic dissection. Longer follow-up to assess the fate of the patent false lumen and the need for subsequent procedures on the remaining thoracic and abdominal aorta is essential before this procedure is widely applied. The Frozen Elephant Trunk for the Treatment of Chronic Dissection of the Thoracic Aorta: A Multicenter ExperienceThe Annals of Thoracic SurgeryVol. 92Issue 5PreviewBecause of the extensive involvement of the aorta, surgical treatment of its chronic dissection continues to represent a surgical challenge. We conducted a study of a multicenter experience to describe a multicenter experience in the treatment of this complex pathology, using the frozen elephant trunk (FET) technique. Full-Text PDF