SPECIAL REPORT For reprint orders, please contact: [email protected]
The Bologna experience with the Thoraflex™ hybrid frozen elephant trunk device Roberto Di Bartolomeo*,1, Luca Di Marco1, Mariano Cefarelli1, Alessandro Leone1, Antonio Pantaleo1, Marco Di Eusanio1, Giuseppe Barberio1 & Davide Pacini1 ABSTRACT Background: We present our initial experience with the frozen elephant trunk using a Thoraflex™ hybrid device for the treatment of the complex thoracic aorta lesions. Materials & methods: Between March 2013 and March 2014, ten patients underwent thoracic aorta surgery using the frozen elephant trunk approach with the Thoraflex hybrid device. Indications for surgery were: residual type A chronic dissection (eight patients), degenerative aneurysm (one patient) and type B chronic aortic dissection (one patient). Selective antegrade cerebral perfusion and moderate hypothermia were used in all cases. Results: In-hospital mortality was 0% and no patients presented with paraplegia, paraparesis or major neurological events. One patient experienced transient ischemic attack. Two patients underwent reoperation for bleeding. All postoperative angiography CT scans confirmed the desired results. Conclusion: Our initial experience demonstrated excellent early results. The Thoraflex hybrid prosthesis with the four-branched arch graft increases the spectrum of techniques available for the surgeon in the treatment of complex diseases of the thoracic aorta. The surgical treatment of diffuse pathologies of the thoracic aorta remains a challenging issue in aortic surgery. Classically, they are treated with a two-step approach known as the ‘elephant trunk procedure’ [1] . Recently, a hybrid repair combining endovascular treatment with conventional surgery, the so-called ‘frozen elephant trunk’ (FET) technique [2–5] , has been described as a single-stage procedure. Various authors reported encouraging results with this technique in acute and chronic aortic diseases [6–14] . Two such hybrid prosthesis are available: the E-vita open plus (Jotec, Inc., Germany) and the Thoraflex™ (Vascutek Ltd, UK) hybrid grafts. Our early experience with the FET technique using the Thoraflex hybrid prosthesis is presented in this article.
KEYWORDS
• aortic dissection • cerebral protection • endovascular prosthesis • hybrid surgery
Materials & methods ●●Patient profile
Between January 2007 and March 2014, a total of 148 patients with complex pathology of the thoracic aorta were treated with the FET procedure in our Institution. Appropriate Institutional Review Board approval has been obtained. In ten patients (7%) between March 2013 and March 2014, a Thoraflex hybrid device was used. Most of them were male (80%) and two (20%) were female. The mean age was 63 ± 9 years (range: 51–78 years). Arterial hypertension (nine patients; 90%), previous aortic surgery (eight patients; 80%) and smoking history (three patients; 30%) were the main risk factors. There were no patients with preoperative chronic renal insufficiency. Indications for surgery included: residual type A aortic dissection in eight patients (80%); chronic aneurysm of the distal arch in one patients; and chronic type B dissection in one patient. Department of Cardiac Surgery, S Orsola-Malpighi Hospital, Via Massarenti 9, 40138 Bologna, Italy *Author for correspondence: Tel.: +39 51 6363361; Fax: +39 51 345990; [email protected] 1
10.2217/FCA.14.56 © 2015 Future Medicine Ltd
Future Cardiol. (2015) 11(1), 39–43
part of
ISSN 1479-6678
39
Special Report Di Bartolomeo, Di Marco, Cefarelli et al. ●●Hybrid endovascular device
The Vascutek Thoraflex hybrid device is composed of a proximal four-branched precoated woven polyester prosthesis sealed to a distal covered stent graft. The stented portion of the graft is a self-expanding endoprosthesis made with polyester and nitinol ring stents, which are attached to a fabric with braided polyester sutures. The graft is available in diameters of 28–40 mm (for the stented portion) and the length of the stent graft is either 100 or 150 mm. Moreover, the proximal and distal parts are available in different sizes. ●●Operative technique
Our technique was been previously described [14,15] . Median sternotomy was used in all patients as well as a guidewire that was inserted through the right femoral artery in the descending thoracic aorta under transesophageal echocardiographic control. Cardiopulmonary bypass was instituted using the right axillary artery, femoral artery, innominate artery or ascending aorta when necessary. In all patients, cerebrospinal fluid drainage was used. Antegrade-selective cerebral perfusion (ASCP) and mild hypothermia were used as cerebral protection methods, as previously described in greater detail [16,17] . At the target nasopharyngeal temperature of 26°C, cardiopulmonary bypass flow was reduced to 1 l/min, the innominate artery was clamped and unilateral brain perfusion was maintained. Special catheters for ASCP connected to the oxygenator with a separate single roller pump head were positioned, during circulatory arrest, into the left common carotid and left subclavian arteries in order to perfuse the left hemisphere. Myocardial protection was achieved with the infusion of cold crystalloid cardioplegia (Custodiol®; Koehler Chemie, Germany). In all patients, the arch was completely resected, the proximal descending aorta was trimmed and some (usually four) internal pledgeted U-stitches externally fixed with Teflon® (Bard Peripheral Vascular, Inc., AZ, USA) felt were positioned. In patients with aortic dissection, the false lumen was surgically obliterated at the level of the distal stump. The stent graft system was then introduced in an antegrade fashion in the descending aorta over the previously positioned stiff guidewire and released. The sheath was pulled back and the splitter was removed from the device. Then, the release clip
40
Future Cardiol. (2015) 11(1)
and the wire were pulled in order to fully release the device. Once the device was fully released, the distal anastomosis was performed between the incorporating sewing collar of the Thoraflex device and the previously prepared descending aorta. The fourth branch of the graft was cannulated and the lower body perfusion was reinitiated. The supraortic vessels were reimplanted to the side branches of the graft starting from the left subclavian artery. At this point, rewarming was initiated and the proximal repair was finally performed. The complete aortic arch and the proximal part of the descending aorta were replaced in all patients, and the ascending aorta was additionally replaced in six patients (60%). Associated procedures included Bentall operations in three patients (30%), an aortic valve sparing operation in one patient and coronary artery bypass grafting in one patient. Results The mean duration of ASCP was 81.4 ± 29.5 min (range: 37–129 min) with a mean cardiopulmonary bypass time of 226.9 ± 98.4 min (range: 139–463 min). The myocardial ischemic times and the visceral ischemic times were 121.2 ± 56.6 min (range: 74–215 min) and 41.8 ± 5.8 min (range: 36–53 min), respectively. The overall in-hospital mortality was 0%. Neither stroke nor ischemic spinal cord injury (SCI) occurred. One patient (10%) had renal failure (dialysis) and one patient (10%) had pulmonary complications requiring prolonged mechanical ventilation. Rethoracotomy for surgical bleeding was required in two patients (20%). The mean hospital stay was 12.7 ± 4 days. All patients underwent predischarge CT scans in which a complete thrombosis of the perigraft space around the stented segment was demonstrated. Discussion Diffuse aneurysmal disease of the thoracic aorta is traditionally treated with the ‘elephant trunk technique’ described by Borst and colleagues in 1983 [1] . This technique facilitates the construction of the distal anastomosis during the initial operation and avoids hazardous dissection of the distal aortic arch during the second step. A relatively new approach – the ‘FET technique’ [5] – combines endovascular treatment with conventional surgery, enabling the single-stage treatment of the combined lesions of the thoracic aorta. The experience with the FET technique is increasing
future science group
The Bologna experience with the Thoraflex™ hybrid frozen elephant trunk device and early as well as midterm results [6–14] are encouraging. However, these operations are very complex and require long operative times. Good results can be obtained only if good methods of myocardial, cerebral and visceral protection are employed. We have had very good experience with Custodiol cardioplegia, which allows for long periods of myocardial ischemia (a single dose of 20–25 ml/kg guarantees 3 h of myocardial protection) [18] . The best available method of brain protection during aortic arch surgery is represented by ASCP [16,17,19–22] and it is highly advocated in this kind of operation, even if there are surgeons who still propose deep hypothermic circulatory arrest as the sole cerebral protection method [23] . FET is associated with a not negligible incidence of SCI and various etiological factors have been advocated. Extensive coverage of the descending aorta with excessive sacrifice of the intercostal arteries represents a strong risk factor for SCI in patients undergoing this surgery [24] . The same authors suggested that thromboembolism could be another possible mechanism in the presence of severe atherosclerosis at the distal landing zone, which was associated with SCI in 36% of such patients. In our limited series of ten patients treated with the Thoraflex prosthesis, we have not had any cases of SCI. All patients received a short stent graft (100 mm) and the mean visceral ischemic time was 41 min. SCI during FET surgery is multifactorial and by shortening the length of the descending aorta coverage and reducing the time of spinal cord ischemia, its incidence can probably be reduced. Cerebrospinal fluid drainage, even in isolated endovascular surgery, has been demonstrated to be an effective means of preventing SCI [25,26] and its use is always recommended during this kind of surgery. We found the FET procedure to be very useful, especially in chronic dissection after acute type A aortic dissection repair or in the case of type B dissection associated with ascending or arch aneurysms. In type B aortic dissection, sealing of the primary tear is the goal of the endovascular procedure in order to restore the flow into the true lumen, leading to thrombosis of the false lumen. This is the same objective we would like to obtain with the FET technique. Meticulous evaluation of the thoracoabdominal aorta has to be conducted before surgery in order to determine the relashionship between the true and the false lumen, the presence and the number of re-entries in the descending and abdominal aorta and the origin of the abdominal arteries. Visceral
future science group
Special Report
ischemia can occur after complete sealing of the false lumen if the abdominal arteries arise from the false lumen itself and no re-entry is present in the distal aorta. Since we introduced the FET in our department, we have not observed any cases of visceral malperfusion due to false lumen occlusion because of the known presence of re-entry sites in the distal aorta. However, we contraindicate the FET procedure if the preoperative CT scan does not visualize re-entry sites in the distal descending thoracic and/or abdominal aorta and the visceral arteries arise from the false lumen. The correct positioning of the hybrid graft can be achieved using a guidewire positioned in the true lumen under transesophageal echocardiography before starting the cardiopulmonary bypass. Moreover, transesophageal echocardiography provides useful informations about the correct opening of the stent. Incomplete sealing of the primary tear is not uncommon; however, in these cases, a complete or partial thrombosis of the false lumen can occur later, justifying a wait-and-see policy [27] . For these patients, a close follow-up is necessary. In case of a persistent perfused false lumen, a further repair can be easily performed. The present study presents some limitations, the main one of which being related to the very limited number of the patients that were studied. Conclusion The FET represents an effective surgical option for the treatment of complex disease of the thoracic aorta. Patients have to be carefully followed up due to a possible evolution of the aortic lesion, which can require a prompt endovascular or surgical treatment. The Thoraflex hybrid prosthesis facilitates the distal anastomosis and allows separate supraortic vessel reimplantation. However, long-term follow-up is required. Future perspective The FET represents the evolution of the classic elephant trunk technique and it has made the single-stage treatment of complex and diffuse diseases of the thoracic aorta possible. In the coming years, the FET will be applied to even more complicated cases. In patients with acute dissection, the FET will positively affect the prognosis, reducing the need of further distal aortic operations in the long term. Moreover, the development of new materials will provide greater conformability and adaptability of the stent portion to the fragile aortic tissues.
www.futuremedicine.com
41
Special Report Di Bartolomeo, Di Marco, Cefarelli et al. Financial & competing interests disclosure The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes
employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties. No writing assistance was utilized in the production of this manuscript.
EXECUTIVE SUMMARY ●●
Diffuse pathologies of the thoracic aorta remain challenging for cardiac surgeons.
●●
Classically, they are treated with a two-step approach known as the ‘elephant trunk procedure’.
●●
The ‘frozen elephant trunk technique’ combines endovascular treatment with conventional surgery, enabling the single-stage treatment of the combined lesions of the thoracic aorta.
●●
The Thoraflex™ hybrid prosthesis with a four-branched arch graft increases the spectrum of techniques available for the surgeon in the treatment of complex diseases of the thoracic aorta.
References 1
2
3
4
5
6
7
42
8
Borst HG, Walterbusch G, Schaps D. Extensive aortic replacement using the elephant trunk prosthesis. J. Thorac. Cadiovasc. Surg. 31(1), 37–40 (1983). Kato M, Ohnishi K, Kaneko M et al. New graft-implanting method for thoracic aortic aneurysm or dissection with a stented graft. Circulation 94(9 Suppl.), II188–II193 (1996). Suto Y, Yasuda K, Shiiya N et al. Stented elephant trunk procedure for an extensive aneurysm involving distal aortic arch and descending aorta. J. Thorac. Cardiovasc. Surg. 112(5), 1389–1390 (1996). 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. 74(5), S1821–S1824 (2002). Karck M, Chavan A, Hagl C, Holger F, Galanski M, Haverich A. The frozen elephant technique: a new treatment for thoracic aortic aneurysm. J. Thorac. Cardiovasc. 125(6), 1550–1553 (2003). Schoenhoff FS, Schmidli J, Eckstein FS, Berdat PA, Immer FF, Carrel TP. The frozen elephant trunk: an interesting hybrid endovascular–surgical technique to treat complex pathologies of the thoracic aorta. J. Vasc. Surg. 45(3), 597–599 (2007). Weiss G, Tsagakis K, Jakob H et al. The frozen elephant trunk technique for the treatment of complicated type B aortic dissection with involvement of the aortic arch: multicentre early experience. Eur. J. Cardiothorac. Surg. doi:10.1093/ejcts/ ezu067 (2014) (Epub ahead of print).
9
Pacini D, Tsagakis K, Jakob H et al. The frozen elephant trunk for the treatment of chronic dissection of the thoracic aorta: a multicenter experience. Ann. Thorac. Surg. 92(5), 1663–1670 (2011). Tsagakis K, Pacini D, Di Bartolomeo R et al. Multicenter early experience with extended aortic repair in acute aortic dissection: is simultaneous descending stent grafting justified? J. Thorac. Cardiovasc. Surg. 140(6 Suppl.), S116–S120 (2010).
10 Roselli EE, Rafael A, Soltesz EG, Canale L,
Lytle BW. Simplified frozen elephant trunk repair for acute DeBakey type I dissection. J. Thorac. Cardiovasc. Surg. 145(3 Suppl.), S197–S201 (2013). 11 Ius F, Fleissner F, Pichlmaier M et al. Total
aortic arch replacement with the frozen elephant trunk technique: 10-year follow-up single-centre experience. Eur. J. Cardiothorac. Surg. 44(5), 949–957 (2013). 12 Sun L, Qi R, Zhu J, Liu Y, Zheng J. Total arch
replacement combined with stented elephant trunk implantation: a new ‘standard’ therapy for type a dissection involving repair of the aortic arch? Circulation 123(9), 971–978 (2011). 13 Di Eusanio M, Armaro A, Di Marco L et al.
Short- and midterm results after hybrid treatment of chronic aortic dissection with the frozen elephant trunk technique. Eur. J.Cardiothorac. Surg. 40(4), 875–880 (2011). 14 Di Bartolomeo R, Pacini D, Savini C et al.
Complex thoracic aortic disease: single-stage procedure with the frozen elephant trunk technique. J. Thorac. Cardiovasc. Surg. 140(6 Supp.l), S81–S85 (2010). 15 Di Bartolomeo R, Di Marco L, Armaro A et al.
Treatment of complex disease of the thoracic
Future Cardiol. (2015) 11(1)
aorta: the frozen elephant trunk technique with the E-vita open prosthesis. Eur. J. Cardiothorac. Surg. 35(4), 671–675 (2009). 16 Di Bartolomeo R, Pacini D, Di Eusanio M,
Pierangeli A. Antegrade selective cerebral perfusion during operations on the thoracic aorta: our experience. Ann. Thorac. Surg. 70(1), 10–15 (2000). 17 Pacini D, Leone A, Di Marco L et al.
Antegrade selective cerebral perfusion in thoracic aorta surgery: safety of moderate hypothermia. Eur. J. Cardiothorac. Surg. 31(4), 618–622 (2007). 18 Ackemann J, Gross W, Mory M, Schaefer M,
Gebhard MM. Celsior versus custodiol: early postischemic recovery after cardioplegia and ischemia at 5 degrees C. Ann. Thorac. Surg. 74(2), 522–529 (2002). 19 Bachet J, Guilmet D, Goudot B et al.
Antegrade cerebral perfusion with cold blood: a 13-year experience. Ann. Thorac. Surg. 67(6), 1874–1878; discussion 1891–1874 (1999). 20 Griepp RB. Cerebral protection during aortic
arch surgery. J. Thorac. Cardiovasc. Surg. 121(3), 425–427 (2001). 21 Kazui T, Yamashita K, Washiyama N et al.
Aortic arch replacement using selective cerebral perfusion. Ann. Thorac. Surg. 83(2), S796–S798; discussion S824–S831 (2007). 22 Harrington DK, Walker AS, Kaukuntla H
et al. Selective antegrade cerebral perfusion attenuates brain metabolic deficit in aortic arch surgery: a prospective randomized trial. Circulation 110(11 Suppl. 1), II231–II236 (2004). 23 Gega A, Rizzo JA, Johnson MH,
Tranquilli M, Farkas EA, Elefteriades JA.
future science group
The Bologna experience with the Thoraflex™ hybrid frozen elephant trunk device Straight deep hypothermic arrest: experience in 394 patients supports its effectiveness as a sole means of brain preservation. Ann. Thorac. Surg. 84(3), 759–767 (2007). 24 Flores J, Kunihara T, Shiiya N et al. Extensive
deployment of the stented elephant trunk is associated with an increased risk of spinal
future science group
cord injury. J. Thorac. Cardiovasc. Surg. 131(2), 336–342 (2006). 25 Safi HJ, Miller CC 3rd. Spinal cord
protection in descending thoracic and thoracoabdominal aortic repair. Ann. Thorac. Surg. 67(6), 1937–1939 (1999).
Special Report
in the post-FDA approval era. J. Thorac. Cardiovasc. Surg. 137(1), 117–123 (2009). 27 Xu SD, Huang FJ, Yang F et al. Endovascular
repair of acute type B aortic dissection: early and mid-term results. J. Vasc. Surg. 43(6), 1090–1095 (2006).
26 Adams JD, Angle JF, Matsumoto AH et al.
Endovascular repair of the thoracic aorta
www.futuremedicine.com
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The Bologna experience with the Thoraflex™ hybrid frozen elephant trunk device Roberto Di Bartolomeo*,1, Luca Di Marco1, Mariano Cefarelli1, Alessandro Leone1, Antonio Pantaleo1, Marco Di Eusanio1, Giuseppe Barberio1 & Davide Pacini1 ABSTRACT Background: We present our initial experience with the frozen elephant trunk using a Thoraflex™ hybrid device for the treatment of the complex thoracic aorta lesions. Materials & methods: Between March 2013 and March 2014, ten patients underwent thoracic aorta surgery using the frozen elephant trunk approach with the Thoraflex hybrid device. Indications for surgery were: residual type A chronic dissection (eight patients), degenerative aneurysm (one patient) and type B chronic aortic dissection (one patient). Selective antegrade cerebral perfusion and moderate hypothermia were used in all cases. Results: In-hospital mortality was 0% and no patients presented with paraplegia, paraparesis or major neurological events. One patient experienced transient ischemic attack. Two patients underwent reoperation for bleeding. All postoperative angiography CT scans confirmed the desired results. Conclusion: Our initial experience demonstrated excellent early results. The Thoraflex hybrid prosthesis with the four-branched arch graft increases the spectrum of techniques available for the surgeon in the treatment of complex diseases of the thoracic aorta. The surgical treatment of diffuse pathologies of the thoracic aorta remains a challenging issue in aortic surgery. Classically, they are treated with a two-step approach known as the ‘elephant trunk procedure’ [1] . Recently, a hybrid repair combining endovascular treatment with conventional surgery, the so-called ‘frozen elephant trunk’ (FET) technique [2–5] , has been described as a single-stage procedure. Various authors reported encouraging results with this technique in acute and chronic aortic diseases [6–14] . Two such hybrid prosthesis are available: the E-vita open plus (Jotec, Inc., Germany) and the Thoraflex™ (Vascutek Ltd, UK) hybrid grafts. Our early experience with the FET technique using the Thoraflex hybrid prosthesis is presented in this article.
KEYWORDS
• aortic dissection • cerebral protection • endovascular prosthesis • hybrid surgery
Materials & methods ●●Patient profile
Between January 2007 and March 2014, a total of 148 patients with complex pathology of the thoracic aorta were treated with the FET procedure in our Institution. Appropriate Institutional Review Board approval has been obtained. In ten patients (7%) between March 2013 and March 2014, a Thoraflex hybrid device was used. Most of them were male (80%) and two (20%) were female. The mean age was 63 ± 9 years (range: 51–78 years). Arterial hypertension (nine patients; 90%), previous aortic surgery (eight patients; 80%) and smoking history (three patients; 30%) were the main risk factors. There were no patients with preoperative chronic renal insufficiency. Indications for surgery included: residual type A aortic dissection in eight patients (80%); chronic aneurysm of the distal arch in one patients; and chronic type B dissection in one patient. Department of Cardiac Surgery, S Orsola-Malpighi Hospital, Via Massarenti 9, 40138 Bologna, Italy *Author for correspondence: Tel.: +39 51 6363361; Fax: +39 51 345990; [email protected] 1
10.2217/FCA.14.56 © 2015 Future Medicine Ltd
Future Cardiol. (2015) 11(1), 39–43
part of
ISSN 1479-6678
39
Special Report Di Bartolomeo, Di Marco, Cefarelli et al. ●●Hybrid endovascular device
The Vascutek Thoraflex hybrid device is composed of a proximal four-branched precoated woven polyester prosthesis sealed to a distal covered stent graft. The stented portion of the graft is a self-expanding endoprosthesis made with polyester and nitinol ring stents, which are attached to a fabric with braided polyester sutures. The graft is available in diameters of 28–40 mm (for the stented portion) and the length of the stent graft is either 100 or 150 mm. Moreover, the proximal and distal parts are available in different sizes. ●●Operative technique
Our technique was been previously described [14,15] . Median sternotomy was used in all patients as well as a guidewire that was inserted through the right femoral artery in the descending thoracic aorta under transesophageal echocardiographic control. Cardiopulmonary bypass was instituted using the right axillary artery, femoral artery, innominate artery or ascending aorta when necessary. In all patients, cerebrospinal fluid drainage was used. Antegrade-selective cerebral perfusion (ASCP) and mild hypothermia were used as cerebral protection methods, as previously described in greater detail [16,17] . At the target nasopharyngeal temperature of 26°C, cardiopulmonary bypass flow was reduced to 1 l/min, the innominate artery was clamped and unilateral brain perfusion was maintained. Special catheters for ASCP connected to the oxygenator with a separate single roller pump head were positioned, during circulatory arrest, into the left common carotid and left subclavian arteries in order to perfuse the left hemisphere. Myocardial protection was achieved with the infusion of cold crystalloid cardioplegia (Custodiol®; Koehler Chemie, Germany). In all patients, the arch was completely resected, the proximal descending aorta was trimmed and some (usually four) internal pledgeted U-stitches externally fixed with Teflon® (Bard Peripheral Vascular, Inc., AZ, USA) felt were positioned. In patients with aortic dissection, the false lumen was surgically obliterated at the level of the distal stump. The stent graft system was then introduced in an antegrade fashion in the descending aorta over the previously positioned stiff guidewire and released. The sheath was pulled back and the splitter was removed from the device. Then, the release clip
40
Future Cardiol. (2015) 11(1)
and the wire were pulled in order to fully release the device. Once the device was fully released, the distal anastomosis was performed between the incorporating sewing collar of the Thoraflex device and the previously prepared descending aorta. The fourth branch of the graft was cannulated and the lower body perfusion was reinitiated. The supraortic vessels were reimplanted to the side branches of the graft starting from the left subclavian artery. At this point, rewarming was initiated and the proximal repair was finally performed. The complete aortic arch and the proximal part of the descending aorta were replaced in all patients, and the ascending aorta was additionally replaced in six patients (60%). Associated procedures included Bentall operations in three patients (30%), an aortic valve sparing operation in one patient and coronary artery bypass grafting in one patient. Results The mean duration of ASCP was 81.4 ± 29.5 min (range: 37–129 min) with a mean cardiopulmonary bypass time of 226.9 ± 98.4 min (range: 139–463 min). The myocardial ischemic times and the visceral ischemic times were 121.2 ± 56.6 min (range: 74–215 min) and 41.8 ± 5.8 min (range: 36–53 min), respectively. The overall in-hospital mortality was 0%. Neither stroke nor ischemic spinal cord injury (SCI) occurred. One patient (10%) had renal failure (dialysis) and one patient (10%) had pulmonary complications requiring prolonged mechanical ventilation. Rethoracotomy for surgical bleeding was required in two patients (20%). The mean hospital stay was 12.7 ± 4 days. All patients underwent predischarge CT scans in which a complete thrombosis of the perigraft space around the stented segment was demonstrated. Discussion Diffuse aneurysmal disease of the thoracic aorta is traditionally treated with the ‘elephant trunk technique’ described by Borst and colleagues in 1983 [1] . This technique facilitates the construction of the distal anastomosis during the initial operation and avoids hazardous dissection of the distal aortic arch during the second step. A relatively new approach – the ‘FET technique’ [5] – combines endovascular treatment with conventional surgery, enabling the single-stage treatment of the combined lesions of the thoracic aorta. The experience with the FET technique is increasing
future science group
The Bologna experience with the Thoraflex™ hybrid frozen elephant trunk device and early as well as midterm results [6–14] are encouraging. However, these operations are very complex and require long operative times. Good results can be obtained only if good methods of myocardial, cerebral and visceral protection are employed. We have had very good experience with Custodiol cardioplegia, which allows for long periods of myocardial ischemia (a single dose of 20–25 ml/kg guarantees 3 h of myocardial protection) [18] . The best available method of brain protection during aortic arch surgery is represented by ASCP [16,17,19–22] and it is highly advocated in this kind of operation, even if there are surgeons who still propose deep hypothermic circulatory arrest as the sole cerebral protection method [23] . FET is associated with a not negligible incidence of SCI and various etiological factors have been advocated. Extensive coverage of the descending aorta with excessive sacrifice of the intercostal arteries represents a strong risk factor for SCI in patients undergoing this surgery [24] . The same authors suggested that thromboembolism could be another possible mechanism in the presence of severe atherosclerosis at the distal landing zone, which was associated with SCI in 36% of such patients. In our limited series of ten patients treated with the Thoraflex prosthesis, we have not had any cases of SCI. All patients received a short stent graft (100 mm) and the mean visceral ischemic time was 41 min. SCI during FET surgery is multifactorial and by shortening the length of the descending aorta coverage and reducing the time of spinal cord ischemia, its incidence can probably be reduced. Cerebrospinal fluid drainage, even in isolated endovascular surgery, has been demonstrated to be an effective means of preventing SCI [25,26] and its use is always recommended during this kind of surgery. We found the FET procedure to be very useful, especially in chronic dissection after acute type A aortic dissection repair or in the case of type B dissection associated with ascending or arch aneurysms. In type B aortic dissection, sealing of the primary tear is the goal of the endovascular procedure in order to restore the flow into the true lumen, leading to thrombosis of the false lumen. This is the same objective we would like to obtain with the FET technique. Meticulous evaluation of the thoracoabdominal aorta has to be conducted before surgery in order to determine the relashionship between the true and the false lumen, the presence and the number of re-entries in the descending and abdominal aorta and the origin of the abdominal arteries. Visceral
future science group
Special Report
ischemia can occur after complete sealing of the false lumen if the abdominal arteries arise from the false lumen itself and no re-entry is present in the distal aorta. Since we introduced the FET in our department, we have not observed any cases of visceral malperfusion due to false lumen occlusion because of the known presence of re-entry sites in the distal aorta. However, we contraindicate the FET procedure if the preoperative CT scan does not visualize re-entry sites in the distal descending thoracic and/or abdominal aorta and the visceral arteries arise from the false lumen. The correct positioning of the hybrid graft can be achieved using a guidewire positioned in the true lumen under transesophageal echocardiography before starting the cardiopulmonary bypass. Moreover, transesophageal echocardiography provides useful informations about the correct opening of the stent. Incomplete sealing of the primary tear is not uncommon; however, in these cases, a complete or partial thrombosis of the false lumen can occur later, justifying a wait-and-see policy [27] . For these patients, a close follow-up is necessary. In case of a persistent perfused false lumen, a further repair can be easily performed. The present study presents some limitations, the main one of which being related to the very limited number of the patients that were studied. Conclusion The FET represents an effective surgical option for the treatment of complex disease of the thoracic aorta. Patients have to be carefully followed up due to a possible evolution of the aortic lesion, which can require a prompt endovascular or surgical treatment. The Thoraflex hybrid prosthesis facilitates the distal anastomosis and allows separate supraortic vessel reimplantation. However, long-term follow-up is required. Future perspective The FET represents the evolution of the classic elephant trunk technique and it has made the single-stage treatment of complex and diffuse diseases of the thoracic aorta possible. In the coming years, the FET will be applied to even more complicated cases. In patients with acute dissection, the FET will positively affect the prognosis, reducing the need of further distal aortic operations in the long term. Moreover, the development of new materials will provide greater conformability and adaptability of the stent portion to the fragile aortic tissues.
www.futuremedicine.com
41
Special Report Di Bartolomeo, Di Marco, Cefarelli et al. Financial & competing interests disclosure The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes
employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties. No writing assistance was utilized in the production of this manuscript.
EXECUTIVE SUMMARY ●●
Diffuse pathologies of the thoracic aorta remain challenging for cardiac surgeons.
●●
Classically, they are treated with a two-step approach known as the ‘elephant trunk procedure’.
●●
The ‘frozen elephant trunk technique’ combines endovascular treatment with conventional surgery, enabling the single-stage treatment of the combined lesions of the thoracic aorta.
●●
The Thoraflex™ hybrid prosthesis with a four-branched arch graft increases the spectrum of techniques available for the surgeon in the treatment of complex diseases of the thoracic aorta.
References 1
2
3
4
5
6
7
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