HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Abstract Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Add to Personal Folders Download to citation manager Author home page(s): Christian Hagl Klaus Kallenbach Axel Haverich Matthias Karck Permission Requests Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Baraki, H. Articles by Karck, M. Search for Related Content PubMed PubMed Citation Articles by Baraki, H. Articles by Karck, M. Related Collections Great vessels

Ann Thorac Surg 2007;83:S819-S823
© 2007 The Society of Thoracic Surgeons

---

Supplement

The Frozen Elephant Trunk Technique for Treatment of Thoracic Aortic Aneurysms

^a Department of Thoracic and Cardiovascular Surgery, Hannover Medical School, Hannover, Germany
^b Department of Radiology, Hannover Medical School, Hannover, Germany

Accepted for publication October 17, 2006.

^_* Address correspondence to Dr Baraki, Hannover Medical School, Department of Thoracic and Cardiovascular Surgery, Carl-Neuberg-Strasse 1, 30625 Hannover, Germany. (Email: hassinabaraki{at}yahoo.com).

Presented at Aortic Surgery Symposium X, New York, NY, April 27–28, 2006.

	Abstract

Top Abstract Introduction Material and Methods Results Comment References

 
BACKGROUND: The frozen elephant trunk technique allows for single-stage repair of combined aortic arch and descending aortic aneurysms using a hybrid prosthesis with a stented and a nonstented end. This report summarizes the operative and follow-up data (mean follow-up: 20 months) with this new treatment.

METHODS: Between September 2001 and March 2006, 39 patients (15 women; mean age, 62 years) were operated on after approval by the local Institutional Review Board. Indications for operation were aneurysms in 18 patients and aortic dissections in 21. The stented end of the hybrid prosthesis was placed through the opened aortic arch under fluoroscopic control using hypothermic circulatory arrest and selective antegrade cerebral perfusion.

RESULTS: All patients survived the procedure. Five patients (12.8%) died early postoperatively, with two deaths directly related to the procedure. Symptoms of neurologic dysfunction developed in 5 patients and resolved completely in 2. In 1 patient, the descending aorta was perforated owing to misplacement of the stented end of the hybrid prosthesis. In 23 of 25 patients with postoperative computed tomography imaging (>6 months postoperatively), complete thrombus formation around the frozen elephant trunk was observed.

CONCLUSIONS: This procedure is performed through a median sternotomy and combines the concepts of the elephant trunk principle and endovascular stenting of descending aortic aneurysms. Favorable intraoperative and postoperative results in the follow-up with thrombus formation around the stented descending aortic segment has encouraged us to evaluate all patients with thoracic aneurysms extending proximal and distal of the left subclavian artery for this treatment.

	Introduction

Top Abstract Introduction Material and Methods Results Comment References

 
Patients with extensive aortic aneurysms involving the ascending aorta, aortic arch, and the descending aorta are still considered to be a challenge for many cardiovascular surgeons [1]. In this context, major concerns include the adequate protection of the heart, the management of the aortic valve, the protection of the brain, the avoidance of respiratory compromise, and the minimization of spinal cord injury and organ failure caused by prolonged circulatory arrest times.

In 1983, Borst and colleagues [2] introduced the elephant trunk procedure to facilitate staged surgery for the aortic arch and the distal aortic segments. The procedure involves the prosthetic replacement of the ascending aorta and the aortic arch with an elephant trunk extension of the arch graft into the descending aorta through a median sternotomy. In a second-stage operation, the elephant trunk can be extended to the desired level through a lateral thoracotomy; however, the cumulative risk for early mortality adds up to 15% after a stage-two repair. Furthermore, many patients fail to return for the second operation; they die owing to aortic rupture during the time interval between the procedures, or comorbidities preclude another procedure through a lateral thoracotomy [3, 4].

To complete the surgical treatment during a single operation through a median sternotomy, we introduced the "frozen elephant trunk" procedure [5]. A prototype, hybrid prosthesis stent graft (Chavan-Haverich endograft, Curative Medical Devices GmbH, Dresden, Germany) is placed into the descending aorta in an antegrade fashion though the opened aortic arch, and the ascending aorta and the aortic arch are replaced conventionally [5]. In this article we briefly report our surgical experience with this novel combined surgical and interventional approach.

	Material and Methods

Top Abstract Introduction Material and Methods Results Comment References

 
Patients
The frozen elephant trunk procedure was approved by the Institutional Review Board of Hannover Medical School. Between September 2001 and March 2006, 39 patients with combined pathologies of the aortic arch and the descending aorta were operated on using the hybrid prosthesis. Informed consent was required in each case. Mean patient age was 62 years (range, 37 to 78 years), and 11 patients were older than 70 years; 15 (38.5%) were women.

Most patients presented with aortic dissection: 4 (10.3%) with an acute type A aortic dissection, 11 (28.2%) with a chronic type A dissection, 3 (7.7%) had an acute type B aortic dissection, and 3 (7.7%) had a chronic type B aortic dissection. The indication for intervention in patients with chronic dissections was aortic dilatation of 70 ± 18 mm (range, 50 to 113 mm) in chronic type A dissection and 60 ± 5 mm (range, 55 to 65 mm) in chronic type B dissection.

The second most frequent pathology, present in 18 (46.2%), was an aortic aneurysm proximal and distal to the left subclavian artery. The maximal aortic diameter in these patients was 59 ± 8 mm (range, 47 to 73 mm). Additional cardiac pathology included severe coronary artery disease in 11 patients (28.2%) and aortic valve disease in 11 (28.2%). Comorbidities are summarized in Table 1.

View larger version (27K): [in this window] [in a new window]   Fig 1. The hybrid prosthesis (Chavan-Haverich endograft, Curative GmbH, Dresden, Germany) made of a woven vascular prosthesis with stainless stents affixed to the inner aspects at the distal end. The proximal end consists of a Dacron sleeve (DuPont, Wilmington, DE) ready for conventional surgical handling. (L = length.)

In each patient, spiral computed tomography angiography of the thoracic aorta was performed preoperatively to assess the extent of the aneurysm or dissection and to determine the appropriate size of the endograft.

Surgery
Cardiopulmonary bypass was used in all patients. Central cannulation of the ascending aorta and the right atrium was preferred. In 4 patients (10.3%) who underwent resternotomy, the groin vessels were cannulated before because the ascending aortic aneurysm encroached upon the sternum. Core cooling was accomplished to 26 ± 2°C rectal temperature. After induction of cardioplegic cardiac arrest, cardiopulmonary bypass was discontinued.

The aortic arch was then opened longitudinally. Selective antegrade cerebral perfusion with cold blood at a temperature of 15°C and a volume of 250 to 450 mL/min was initiated after ostial cannulation of the left common carotid artery and the brachiocephalic trunk. Afterwards, the stented portion of the hybrid prosthesis was deployed in the descending aorta. In the first 5 patients, the implantation was over an antegrade-placed superstiff guidewire. Prompted by perforation of the aortic wall with the introducer system in a patient with a tortuous descending aorta, a through-and-through transfemoral guidewire technique was used in all subsequent patients.

The distal ending site of the stent graft was at or above the tenth thoracic vertebra in all patients. After deployment, the stented portion of the prosthesis was modulated onto the aortic wall with the help of an appropriately sized balloon catheter (Medtronic, Minneapolis, MN). The nonstented Dacron graft segment was sutured circumferentially to the aorta distal to the origin of the left subclavian artery. The supraaortic branches were then reimplanted en bloc into an appropriately sized window of the graft. A proximal graft-to-aortic anastomosis at any desired level of the ascending aorta completed the repair.

In 23 patients (59%), the entire aortic arch and the proximal segment of the descending aorta were replaced, and in 11 (28.2%), the ascending aorta was also replaced. In 5 (12.8%) other patients whose aneurysms were limited to the proximal descending aorta, implantation of the hybrid prosthesis into the descending aorta was enabled by a limited, 3-cm to 4-cm longitudinal T-shaped incision of the aortic arch. The nonstented endograft segment was sutured circumferentially distal to the level of the left subclavian artery before closure of the aortotomy. Two of the 5 patients required additional complete myocardial revascularization. In 21 patients, additional procedures were required, including aortic valve reconstruction with David procedure in 7 (17.9%), aortic valve replacement as a composite in 4 (10.3%), and myocardial revascularization in 12 (30.8%) (Table 2).

	Results

Top Abstract Introduction Material and Methods Results Comment References

In one patient with chronic aortic dissection type A, the aortic wall of the false lumen directly distal to the origin of the left subclavian artery was accidentally injured during surgical preparation. Even though this laceration was sutured and the further course of the operation was uneventful, the patient died from hemorrhage into the left hemithorax 2 days postoperatively. Autopsy revealed that exsanguination resulted from a reopening of the repaired segment.

A 72-year-old patient who sustained a medial artery cerebral infarction died of hemorrhage during elective tracheotomy on postoperative day 7. A further patient died of multiorgan failure after cerebral infarction, and another from retroperitoneal hemorrhage after perforation of the iliac artery. The final patient died of respiratory failure on postoperative day 31. Among the five deaths, 2 patients had an aortic aneurysm and 3 had chronic type A aortic dissection. Three of the five were redo cases, and 3 patients needed additional coronary artery bypass grafts owing to coronary artery disease.

Cardiopulmonary bypass time was 222 ± 67 minutes, aortic cross-clamp time was 133 ± 49 minutes, circulatory arrest time was 69 ± 19 minutes, and time of selective antegrade brain perfusion during circulatory arrest was 56 ± 15 minutes. Vocal cord paralysis occurred in 5 patients (12.8%), 3 of whom were redo cases. Five patients (12.8%) showed central neurologic dysfunction, and in two the symptoms resolved completely before discharge. Two of the 5 patients had a history of stroke, with correlates in the preoperative CT scan of the brain. Reexploration for bleeding was necessary in 5 patients (12.8%).

Follow-Up
Median follow-up was 22 ± 17 months, with an overall survival of 87% (Fig 2). Two patients were lost to follow-up. Postoperative CT scans were obtained in 25 (73.5%) of 34 patients, and in 23 (92%), complete thrombus formation was observed in the perigraft space around the stented segment of the hybrid prosthesis. The average diameter of the stented descending thoracic aorta decreased over time from 63 ± 14 mm (range, 47 to 113 mm) to 54 ± 11 mm (range, 39 to 74 mm; Fig 3).

View larger version (9K): [in this window] [in a new window]   Fig 2. Actuarial survival in months after implantation of hybrid prosthesis. Numbers in parenthesis show the patients remaining at risk at each relevant time point.

View larger version (36K): [in this window] [in a new window]   Fig 3. The maximal diameter of the descending thoracic aorta at the level of the tracheal bifurcation before (clear bars) and after (striped bars) the implantation of the hybrid prosthesis. (AADA = acute aortic dissection type A; CADA = chronic aortic dissection type A; CADB = chronic aortic dissection type B.)

In the other patient with chronic aortic dissection type A, the stented segment of the graft could not be anchored successfully in a previously implanted thoracoabdominal aortic stent graft. The stent slipped proximally during and after release, giving rise to a distal endoleak. This was treated 2 weeks later by placing a commercially available endograft (Talent, Medtronic Inc) transfemorally, thus extending the hybrid endograft distally into the thoracoabdominal graft. A type III endoleak, which was reduced to a tiny contrast extravasation, was found at 6 month follow-up. Initially the patient was treated conservatively, but his thoracoabdominal aneurysm was progressive, causing conventional open repair after an interval of 3.85 years.

Another patient with chronic aortic dissection type A, who was 55 years old, needed a reoperation after an interval of 2.8 years. He underwent an aortic valve replacement and replacement of the ascending aorta with a composite graft. Eleven years later, his aortic arch and his descending aorta were replaced with a hybrid prosthesis. Follow-up CT imaging showed an anastomotic aneurysm up to 58 mm, causing a re-replacement of the ascending aorta and proximal aortic arch. The patient did well and was discharged home on postoperative day 9.

	Comment

Top Abstract Introduction Material and Methods Results Comment References

 
The development of the elephant trunk procedure for aneurysm of the ascending, arch, and descending thoracic aorta has improved the repair of complex aortic lesions by facilitating the proximal anastomosis at the time of the second-stage descending aneurysm repair [2, 6, 7]. Sometimes complications with the first operation render the completion of the second operation unfeasible. The second intervention carries the cumulative risk of two major procedures, an additional risk for mortality up to 5% [8], and a spinal cord injury risk of 3% to 10% [9]. Accordingly, we have developed a single-stage transmediastinal approach with the hybrid prosthesis for patients with ascending, arch, and descending aneurysms [5].

In the conventional elephant trunk operation, the perigraft space around the elephant trunk remains perfused, thereby promoting further aneurysmatic dilatation of the aortic segment [3, 10]. In contrast, the hybrid prosthesis technique allows for progressive thrombus formation in the perigraft space in the descending aorta up to the level of the stent. Widening of the descending aorta has not been observed in our patients, regardless of complete or incomplete thrombus formation. This phenomenon suggests that the stents within the distal segment of the hybrid prosthesis are effective in preventing retrograde flow into the aneurysm.

To mount the hybrid prosthesis into an adequately flexible and thin delivery system, we used thin Dacron (0.36 mm in width), which is thinner than the Dacron used in conventional aortic surgery. The hybrid prosthesis is pretreated with collagen during fabrication. In some instances, extra sealing with fibrin glue was necessary to render the graft completely hemostatic.

The initial learning curve and the high incidence of concomitant procedures (Table 2) may explain the perioperative mortality rate of 12.8% [7, 11, 12]. However, groups describing one-stage surgical replacement of the thoracic aorta have also reported mortality rates of between 14% and 16% [11, 13]. A major technical improvement over time was the introduction of a guidewire through the femoral artery that helps to discriminate the true and the false lumen.

The 12.8% incidence of stroke remains a concern because it is higher than expected [12]. In 2 of the 5 patients, however, symptoms resolved completely before discharge, and 2 were at higher risk owing to previous cerebrovascular incidents. Three of the 5 patients who developed recurrent nerve paralysis were redo cases.

The position of the distal anastomosis is quite close to the recurrent nerve. Special attention should be paid to the preparation of the aortic arch to save the nerve. Recurrent nerve paralysis not only reduces the patient’s quality of life but also survival by leading to disorders including aspiration pneumonia. Rehabilitation should therefore be performed consistently and at an early stage.

No paraplegia caused by spinal cord injury developed in patients in our series. This rate is quite low compared with the significant paraplegia rates reported with similar open surgical approaches, but it correlates with endovascular stent graft reports of the descending aorta [14–16]. The main reason for the reduced spinal cord injury frequency in our series might be in the indication for hybrid prosthesis, which was limited to patients with an aneurysm that involved only the first half of the descending aorta, regardless of its size. Furthermore, stent graft fabrication was adjusted specifically to each patient’s individual pathology. The proximal extent of the aneurysm with regard to arch involvement was not critical because the quality of the anastomosis distal to the origin of the subclavian artery is rather dependent on the condition of the aortic tissue than on the actual aortic diameter at that segment.

The use of the hybrid prosthesis enables safe anchoring of its proximal vascular graft segment by a circumferential, hand-sewn anastomosis distal to the origin of the left subclavian artery. This is at the expense of a probably somewhat extended circulatory arrest time compared with the time required for antegrade implantation of a conventional stent graft with or without its fixation by internal stay sutures.

Similar to observations during follow-up after endovascular stent grafting, we observed either advanced or completed thrombus formation around the frozen elephant trunk after a mean follow-up time of 22 months so far (Fig 4) [17]. In some cases, we found additional shrinkage of the thrombosed aneurysms, which is also a common finding after endovascular stent grafting [18]. Thrombus formation in the perigraft space and shrinkage of the excluded aneurysm are indicative of a reduction of aortic wall stress, thereby reducing the risk of rupture of the stented aortic segment. This finding supports the therapeutic concept of a single-stage antegrade combined open and endovascular repair of complex thoracic aortic aneurysm using a hybrid prosthesis, despite the currently relatively high mortality and morbidity rates. We believe the morbidity and mortality rates of this procedure will decrease with increased experience, making it the treatment of choice for complex aortic diseases.

View larger version (49K): [in this window] [in a new window]   Fig 4. Contrast computed tomography reformation of a patient with aortic aneurysm after implantation of a hybrid prosthesis 26 months postoperatively. Perigraft space around the stented segment of the hybrid prosthesis is completely thrombosed.

	References

Top Abstract Introduction Material and Methods Results Comment References

 

1. Svensson LG. The elephant trunk procedure: uses in complex aortic diseases Curr Opin Cardiol 2005;20:491-495.[Medline]
2. Borst HG, Walterbusch G, Schaps D. Extensive aortic replacement using "elephant trunk" prosthesis Thorac Cardiovasc Surg 1983;31:37-40.[Medline]
3. Estrera AL, Miller CC, Porat EE, Huynh TT, Winnerkvist A, Safi HJ. Staged repair of extensive aortic aneurysms Ann Thorac Surg 2002;74:S1803-S1805discussion S1825–32.[Abstract/Free Full Text]
4. Schepens MA, Dossche KM, Morshuis WJ. The elephant trunk technique: operative results in 100 consecutive patients Eur J Cardiothorac Surg 2002;21:276-281.[Abstract/Free Full Text]
5. Karck M, Chavan A, Hagl C, Friedrich H, Galanski M, Haverich A. The frozen elephant trunk technique: a new treatment for thoracic aortic aneurysms J Thorac Cardiovasc Surg 2003;125:1550-1553.[Free Full Text]
6. Borst HG, Frank G, Schaps D. Treatment of extensive aortic aneurysms by a new multiple-stage approach J Thorac Cardiovasc Surg 1988;95:11-13.[Abstract]
7. Heinemann MK, Buehner B, Jurmann MJ, et al. Use of the "elephant trunk technique" in aortic surgery Ann Thorac Surg 1995;60:2-6discussion 7.[Abstract/Free Full Text]
8. Svensson LG, Crawford ES, Hess KR. Deep hypothermia with circulatory arrestDeterminants of stroke and early mortality in 656 patients. J Thorac Cardiovasc Surg 1993;106:19-28discussion 28–31.[Abstract]
9. Williams GM, Perler BA, Burdick JF. Angiographic localization of spinal cord blood supply and its relationship to postoperative paraplegia J Vasc Surg 1991;13:23-33discussion 33–5.[Medline]
10. Kouchoukos NT, Masetti P, Rokkas CK. Single-stage reoperative repair of chronic type A aortic dissection by means of the arch-first technique J Thorac Cardiovasc Surg 2001;122:578-582.[Abstract/Free Full Text]
11. Bachet J, Guilmet D, Goudot B. Antegrade cerebral perfusion with cold blood: a 13-year experience Ann Thorac Surg 1999;67:1874-1878discussion 1891–4.[Abstract/Free Full Text]
12. Svensson LG, Kim KH, Blackstone EH, et al. Elephant trunk procedure: newer indications and uses Ann Thorac Surg 2004;78:109-116discussion 109–16.[Abstract/Free Full Text]
13. Minale C, Splittgerber FH, Reifschneider HJ. Replacement of the entire thoracic aorta in a single stage Ann Thorac Surg 1994;57:850-855.[Abstract]
14. Won JY, Lee DY, Shim WH. Elective endovascular treatment of descending thoracic aortic aneurysms and chronic dissections with stent-grafts J Vasc Interv Radiol 2001;12:575-582.[Medline]
15. Usui A, Fujimoto K, Ishiguchi T, Yoshikawa M, Akita T, Ueda Y. Cerebrospinal dysfunction after endovascular stent-grafting via a median sternotomy: the frozen elephant trunk procedure Ann Thorac Surg 2002;74:1821-1824discussion 1825–32.
16. Mizuno T, Toyama M, Tabuchi N, Wu H, Sunamori M. Stented elephant trunk procedure combined with ascending aorta and arch replacement for acute type A aortic dissection Eur J Cardiothorac Surg 2002;22:504-509.[Abstract/Free Full Text]
17. Chavan A, Lotz J, Oelert F, Galanski M, Haverich A, Karck M. Endoluminal treatment of aortic dissection Eur Radiol 2003;13:2521-2534.[Medline]
18. Yamazaki I, Imoto K, Suzuki S, et al. Midterm results of stent-graft repair for thoracic aortic aneurysms: computed tomographic evaluation Artif Organs 2001;25:223-227.[Medline]

This article has been cited by other articles:

				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]

				D. Pacini, A. Armaro, L. Di Marco, V. Russo, and R. Di Bartolomeo Stent graft coarctation after frozen elephant trunk procedure: An unusual complication J. Thorac. Cardiovasc. Surg., April 1, 2009; 137(4): 1027 - 1029. [Full Text] [PDF]

				T. Kim, T. D. Martin, W. A. Lee, P. J. Hess Jr., C. T. Klodell, C. G. Tribble, R. J. Feezor, and T. M. Beaver Evolution in the management of the total thoracic aorta. J. Thorac. Cardiovasc. Surg., March 1, 2009; 137(3): 627 - 634. [Abstract] [Full Text] [PDF]

				M. A. Pichlmaier, O. E. Teebken, N. Khaladj, J. Weidemann, M. Galanski, and A. Haverich Distal aortic surgery following arch replacement with a frozen elephant trunk Eur. J. Cardiothorac. Surg., September 1, 2008; 34(3): 600 - 604. [Abstract] [Full Text] [PDF]

				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]

				N. Khaladj, M. Shrestha, S. Meck, S. Peterss, H. Kamiya, K. Kallenbach, M. Winterhalter, L. Hoy, A. Haverich, and C. Hagl Hypothermic circulatory arrest with selective antegrade cerebral perfusion in ascending aortic and aortic arch surgery: A risk factor analysis for adverse outcome in 501 patients. J. Thorac. Cardiovasc. Surg., April 1, 2008; 135(4): 908 - 914. [Abstract] [Full Text] [PDF]

				M. Gorlitzer, G. Weiss, M. Thalmann, G. Mertikian, W. Wislocki, J. Meinhart, F. Waldenberger, and M. Grabenwoger Combined Surgical and Endovascular Repair of Complex Aortic Pathologies With a New Hybrid Prosthesis Ann. Thorac. Surg., December 1, 2007; 84(6): 1971 - 1976. [Abstract] [Full Text] [PDF]

This Article Abstract Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Add to Personal Folders Download to citation manager Author home page(s): Christian Hagl Klaus Kallenbach Axel Haverich Matthias Karck Permission Requests Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Baraki, H. Articles by Karck, M. Search for Related Content PubMed PubMed Citation Articles by Baraki, H. Articles by Karck, M. Related Collections Great vessels